US20230034546A1 - Display device and hand-held electronic device - Google Patents

Abstract

An electronic device includes a liquid crystal display device having a first substrate, a second substrate bonded to the first substrate, with liquid crystal material held between the first substrate and the second substrate, and an upper polarizing plate affixed to the second substrate. A protective member is disposed over the upper polarizing plate, and an adhesive member is disposed between the protective member and the upper polarizing plate without an air layer between the protective member and the upper polarizing plate. The protective member is configured as a protective cover of the electronic device.

Description

CROSS REFERENCE TO RELATED APPLICATION
• This application is a continuation of U.S. application Ser. No. 13/446,331, filed Apr. 13, 2013, which is a continuation of U.S. application Ser. No. 13/279,587, filed Oct. 24, 2011, now U.S. Pat. No. 8,164,717, which is a continuation of U.S. application Ser. No. 12/437,218, filed May 7, 2009, now U.S. Pat. No. 8,045,101, which is a continuation application of U.S. application Ser. No. 11/644,872, filed Dec. 26, 2006, now U.S. Pat. No. 7,532,274, the contents of which are incorporated herein by reference.
CLAIM OF PRIORITY
• The present application claims priority from Japanese Application JP 2005-372185 filed on Dec. 26, 2005, the content of which is hereby incorporated by reference into this application.
BACKGROUND OF THE INVENTIONField of the Invention
• The present invention relates to a liquid crystal display and a display. In particular, the present invention is concerned with a technique applicable effectively to a liquid crystal display (module) used in a hand-held electronic device such as a mobile telephone terminal.
Description of the Related Art
• A thin display such as a liquid crystal display has been conventionally used for a display used in a hand-held electronic device such as a mobile telephone terminal or a PDA (Personal Digital Assistant).
• The liquid crystal display is a display having a liquid crystal display panel comprising a pair of substrates and a liquid crystal material held therebetween. One of the paired substrates is generally called a TFT substrate and, for example, comprises a glass substrate, as well as TFTs (Thin Film Transistor) and pixel electrodes formed on the substrate. The other substrate is generally called a counter substrate and, for example, comprises a glass substrate and a color filter, etc. formed thereon. In the case where the liquid crystal material driving method is a longitudinal electric field type, common electrodes (also called counter electrodes) opposed to the pixel electrodes are formed on the counter substrate side. In the case where the liquid crystal material driving method is a lateral electric field type, the common electrodes are formed on the TFT substrate side.
• With the recent tendency toward the reduction in thickness of the hand-held electronic device, the liquid crystal display used therein has also been becoming more and more thin. For example, as a method of reducing the thickness of a liquid crystal panel, the method of reducing the thickness of the liquid crystal display is known.
• For example, a method of polishing the glass substrate used in the TFT substrate or the counter substrate is known as the method of reducing the thickness of the liquid crystal display panel.
• Also, as a method of reducing the thickness of a liquid crystal display panel, the method of using a plastic substrate for either one of the TFT substrate or the counter substrate instead of the glass substrate (see, for example, Japanese Patent Laid-Open No. 8-006039 (Patent Document 1)) is known.
SUMMARY OF THE INVENTION
• In the liquid crystal display, when the thickness of the glass substrate used in the TFT substrate or the counter substrate is reduced by polishing in order to reduce the thickness of the liquid crystal display panel, the strength of the glass substrate is deteriorated and the strength of the liquid crystal display panel is also deteriorated. Thus, the method of polishing the glass substrate to reduce the substrate thickness poses the problem that it is difficult to attain both thickness reduction and ensuring of a sufficient strength.
• Moreover, the method of using a plastic substrate instead of the glass substrate poses the problem that the heat resistance and solvent resistance (chemicals resistance) of the plastic substrate are low in comparison with the glass substrate and that therefore the handling of the plastic substrate is difficult for example in the step of forming TFT onto the glass substrate. Further, in the case of a liquid crystal display panel using a glass substrate as the TFT substrate and a plastic substrate as the counter substrate, unevenness in display easily occurs because the substrates differ in the amount of deformation caused by changes of environmental conditions such as temperature and humidity.
• It is an object of the present invention to provide a technique able to attain both thickness reduction of a liquid crystal display panel and ensuring of a sufficient strength of the panel.
• It is another object of the present invention to provide a technique able to reduce the thickness of a hand-held electronic device such as a liquid crystal display (module).
• The above and other objects and novel features of the present invention will become apparent from the following description and the accompanying drawings.
• The following is an outline of typical modes of the present invention as disclosed herein.
• (1) A liquid crystal display comprising a liquid crystal display panel, the liquid crystal display panel having a first substrate, a second substrate disposed on the side of an observer with respect to the first substrate and opposed to the first substrate, a liquid crystal held between the first substrate and the second substrate, an upper polarizing plate disposed on the observer side with respect to the second substrate, and a resin film disposed on the observer side with respect to the upper polarizing plate and affixed in contact with the upper polarizing plate, the resin film being higher in surface hardness than the upper polarizing plate.
• (2) The liquid crystal display according to the above (1), wherein the resin film has a surface hardness of 3 H or harder in terms of surface pencil hardness.
• (3) The liquid crystal display according to the above (1) or (2), wherein the resin film has a thickness of 0.2 mm or more.
• (4) The liquid crystal display according to the above (1) or (2), wherein the resin film has a thickness of 0.2 mm or more and 1 mm or less.
• (5) The liquid crystal display according to any one of the above (1) to (4), wherein the material of the resin film is an acrylic resin or an epoxy resin.
• (6) The liquid crystal display according to any one of the above (1) to (5), wherein the first substrate has a thickness of 0.5 mm or less.
• (7) The liquid crystal display according to any one of the above (1) to (6), wherein the second substrate has a thickness of 0.5 mm or less.
• (8) The liquid crystal display according to any one of the above (1) to (7), wherein the thickness of the first substrate and that of the second substrate are almost equal to each other.
• (9) The liquid crystal display according to any one of the above (1) to (7), wherein the thickness of the second substrate is smaller than that of the first substrate.
• (10) The liquid crystal display according to any one of the above (1) to (7), wherein the thickness of the second substrate is larger than that of the first substrate.
• (11) The liquid crystal display according to any one of the above (1) to (10), wherein the total thickness of the liquid crystal display panel is 2 mm or less.
• (12) The liquid crystal display according to any one of the above (1) to (11), further comprising an upper phase difference plate disposed between the upper polarizing plate and the second substrate.
• (13) The liquid crystal display according to any one of the above (1) to (12), wherein when the liquid crystal display panel is viewed from a front side thereof, an outline of the resin film is smaller than that of the upper polarizing plate.
• (14) The liquid crystal display according to any one of the above (1) to (12), wherein the liquid crystal display panel further comprises a lower polarizing plate disposed on a back surface side of the first substrate, and when the liquid crystal display panel is viewed from the front side thereof, an outline of the resin film and that of the upper polarizing plate are smaller than an outline of the lower polarizing plate.
• (15) The liquid crystal display according to the above (14), further comprising a lower phase difference plate disposed between the lower polarizing plate and the first substrate.
• (16) The liquid crystal display according to any one of the above (1) to (15), wherein the first substrate and the second substrate are glass substrates.
• (17) A liquid crystal display comprising a liquid crystal display panel, the liquid crystal display panel having a first substrate, a second substrate disposed on an observer side with respect to the first substrate and opposed to the first substrate, a liquid crystal held between the first substrate and the second substrate, an upper polarizing plate disposed on the observer side with respect to the second substrate, and a resin film disposed between the upper polarizing plate and the second substrate, the resin film having a thickness of 0.2 mm or more, the upper polarizing plate having a surface hardness of 3 H or harder in terms of surface pencil hardness.
• (18) The liquid crystal display according to the above (17), wherein the resin film has a thickness of 1 mm or less.
• (19) The liquid crystal display according to the above (17) or (18), wherein the thickness of the first substrate and that of the second substrate are almost equal to each other.
• (20) The liquid crystal display according to the above (17) or (18), wherein the thickness of the second substrate is smaller than that of the first substrate.
• (21) The liquid crystal display according to the above (17) or (18), wherein the thickness of the second substrate is larger than that of the first substrate.
• (22) The liquid crystal display according to any one of the above (17) to (21), further comprising an upper phase difference plate disposed between the upper polarizing plate and the second substrate.
• (23) The liquid crystal display according to any one of the above (17) to (22), wherein when the liquid crystal display panel is viewed from a front side thereof, an outline of the upper polarizing plate is smaller than that of the resin film.
• (24) The liquid crystal display according to any one of the above (17) to (23), wherein the liquid crystal display panel further comprises a lower polarizing plate disposed on a back surface side of the first substrate, and when the liquid crystal display panel is viewed from the front side thereof, an outline of the upper polarizing plate is smaller than that of the lower polarizing plate.
• (25) The liquid crystal display according to the above (24), wherein when the liquid crystal display panel is viewed from the front side thereof, an outline of the resin film is smaller than that of the lower polarizing plate.
• (26) The liquid crystal display according to the above (24), wherein when the liquid crystal display panel is viewed from the front side thereof, an outline of the resin film is larger than that of the lower polarizing plate.
• (27) The liquid crystal display according to any one of the above (24) to (26), further comprising a lower phase difference plate disposed between the lower polarizing plate and the first substrate.
• (28) The liquid crystal display according to any one of the above (17) to (27), wherein the first substrate and the second substrate are glass substrates.
• (29) A liquid crystal display comprising a liquid crystal display panel, the liquid crystal display panel having a first substrate, a second substrate disposed on an observer side with respect to the first substrate and opposed to the first substrate, a liquid crystal held between the first substrate and the second substrate, an upper polarizing plate disposed on the observer side with respect to the second substrate, a lower polarizing plate disposed on a back surface side of the first substrate, and a resin film affixed in contact with a back surface side of the lower polarizing plate, wherein the total thickness of the first substrate and the second substrate is 0.5 mm or less.
• (30) The liquid crystal display according to the above (29), wherein the resin film has a thickness of 0.1 mm or more and 0.3 mm or less.
• (31) The liquid crystal display according to the above (29) or (30), wherein the thickness of the first substrate and that of the second substrate are almost equal to each other.
• (32) The liquid crystal display according to the above (29) or (30), wherein the thickness of the second substrate is smaller than that of the first substrate.
• (33) The liquid crystal display according to the above (29) or (30), wherein the thickness of the second substrate is larger than that of the first substrate.
• (34) The liquid crystal display according to any one of the above (29) to (33), wherein the first substrate and the second substrate are glass substrates.
• (35) A liquid crystal display comprising a liquid crystal display panel, the liquid crystal display panel having a first substrate, a second substrate disposed on an observer side with respect to the first substrate and opposed to the first substrate, a liquid crystal held between the first substrate and the second substrate, an upper polarizing plate disposed on the observer side with respect to the second substrate, a lower polarizing plate disposed on a back surface side of the first substrate, and a resin film disposed between the lower polarizing plate and the first substrate, wherein the total thickness of the first substrate and the second substrate is 0.5 mm or less.
• (36) The liquid crystal display according to the above (35), wherein the resin film has a thickness of 0.1 mm or more and 0.3 mm or less.
• (37) The liquid crystal display according to the above (35) or (36), wherein the thickness of the first substrate and that of the second substrate are almost equal to each other.
• (38) The liquid crystal display according to the above (35) or (36), wherein the thickness of the second substrate is smaller than that of the first substrate.
• (39) The liquid crystal display according to the above (35) or (36), wherein the thickness of the second substrate is larger than that of the first substrate.
• (40) The liquid crystal display according to any of the above (35) to (39), wherein the first substrate and the second substrate are glass substrates.
• (41) A display comprising a display panel, the display panel comprising a first substrate, a second substrate disposed on an observer side with respect to the first substrate and opposed to the first substrate, and an upper polarizing plate disposed on the observer side with respect to the second substrate, wherein the first substrate and the second substrate are glass substrates and there is provided a resin film disposed on the observer side with respect to the upper polarizing plate and affixed in contact with the upper polarizing plate, the resin film having a surface hardness of 3 H or harder in terms of surface pencil hardness.
• In connection with the liquid crystal display according to the present invention, in the liquid crystal display of the first invention (1), a resin film is affixed in contact with the upper polarizing plate of the liquid crystal display panel, the resin film having a surface hardness higher than that of the upper polarizing plate. In the liquid crystal display panel having such a resin film, the resin film functions as a reinforcing member, whereby the strength of the liquid crystal display panel is enhanced. Therefore, even if one or both of the first and second substrates are reduced in thickness, it is possible to ensure a sufficient strength of the liquid crystal display panel. With the resin film having the surface pencil hardness of 3 H or harder, the liquid crystal display panel becomes difficult to be damaged. Consequently, when the liquid crystal display (module) having this liquid crystal display panel is installed into a mobile telephone terminal, a protective cover for protecting the liquid crystal display panel is not necessary to be attached to the outer surface of the mobile telephone terminal. As a result, a display unit of the mobile telephone terminal can be made thin.
• It is preferable that the thickness of the resin film be, for example, 0.2 mm or more and 1 mm or less. It is preferable that the resin film be formed of a material high in light transmittance, especially a colorless, transparent material. As an example of such a material there is an acrylic resin or an epoxy resin. In the case of using an acrylic resin or an epoxy resin as the material of the resin film, the surface of the resin is subjected to a hard coating treatment so as to give a surface pencil hardness of 3 H or harder. the surface pencil hardness is meant a hardness with which the material surface is damaged when a line is drawn on the material surface with a pencil. That is, the surface pencil hardness of 3 H means that the film surface gets not damaged when a line is drawn on the film surface with a pencil with a pencil hardness of 3 H or softer.
• It is preferable that the first and second substrates each have a thickness of 0.5 mm or less. The thickness of the first substrate and that of the second substrate may be almost equal to or different from each other. In particular, the second substrate with the resin film affixed thereto is reinforced by the resin film and therefore, even if it is thinner than the first substrate, it is possible to ensure a sufficient strength. For example, in the case where the liquid crystal display panel is of a lateral electric field driving type called IPS (In Plane Switching), a conductor film for the prevention of electric charging may be provided on the surface to which the upper polarizing plate is affixed. In this case, for example, it is impossible to reduce the thickness of the second substrate by polishing. Therefore, in the case where the aforesaid conductor film is provided on the second substrate, the first substrate is made thinner than the second substrate to reduce the thickness of the liquid crystal display panel. In this case, it is preferable that the thickness of the resin film, that of the first substrate and that of the second substrate be set so as to give a liquid crystal display panel thickness of 2 mm or less.
• In such a liquid crystal display panel, it is preferable that an outline of the resin film be smaller than that of the upper polarizing plate for example when the panel is viewed from the front side thereof. For example, when the liquid crystal display having the liquid crystal display panel is installed into a mobile telephone terminal, there usually is formed a slight gap between the sheath of the mobile telephone terminal and the liquid crystal display panel, and water gets into the inside of the mobile telephone terminal from the outside through the gap. In this case, the outline of the resin film is made smaller than that of the upper polarizing plate, whereby the upper polarizing plate and the sheath of the mobile telephone terminal can be affixed together between the outer periphery of the resin film and that of the upper polarizing plate using a pressure-sensitive adhesive or the like to fill up the gap. In this way it is possible to prevent the entry of water into the inside of the sheath.
• In such a liquid crystal panel, for example, the lower polarizing plate may be disposed on the back surface side of the first substrate. In this case, for example when the liquid crystal display panel is viewed from the front side, it is preferable that the outline of the resin film and that of the upper polarizing plate be smaller than the outline of the lower polarizing plate.
• In such a liquid crystal display panel, for example, an upper phase difference plate may be disposed between the upper polarizing plate and the second substrate. Likewise, a lower phase difference plate may be disposed between the lower polarizing plate and the first substrate.
• In such a liquid crystal display panel it is preferable that both first and second substrates be glass substrates. Even in the case of using glass substrates as the first and second substrates, it is possible to reduce the thickness of each glass substrate because a sufficient strength can be ensured by the resin film. Thus, it is possible to attain both the reduction in thickness of the liquid crystal display panel and ensuring of a sufficient strength.
• In connection with the liquid crystal display according to the present invention, in the liquid crystal display of the second invention (17), the resin film is disposed between the second substrate and the upper polarizing plate of the liquid crystal display panel. Also in this case it is preferable that the thickness of the resin film be, for example, 0.2 mm or more and 1 mm or less. In such a liquid crystal display panel, since the upper polarizing plate is disposed most closely to the observer, the surface pencil hardness of the resin film is not required to be 3 H or harder. Instead, in the liquid crystal display of the second invention it is preferable that the surface of the upper polarizing plate be subjected to a hard coating treatment so as to become 3 H or harder in surface pencil hardness. With this configuration, it is possible to obtain the same effect as in the liquid crystal display (liquid crystal display panel) of the first invention.
• Also in the liquid crystal display of the second invention, the thickness of the first substrate and that of the second substrate may be almost equal to each other or either one of the first or second substrates may be reduced in thickness.
• Also in the liquid crystal display of the second invention it is preferable that the outline of the resin film be smaller than that of the upper polarizing plate for example when the liquid crystal display panel is viewed from the front side thereof.
• In the liquid crystal display of the second invention, for example, a lower polarizing plate may be disposed on the back surface side of the first substrate. In this case, it is preferable that the outline of the resin film and that of the upper polarizing plate be smaller than the outline of the lower polarizing plate for example when the liquid crystal display panel is viewed from the front side thereof.
• Moreover, in the liquid crystal display of the second invention, for example, an upper phase difference plate may be disposed between the upper polarizing plate and the second substrate. Likewise, a lower phase difference plate may be disposed between the lower polarizing plate and the first substrate. The upper phase difference plate may be disposed between the second substrate and the resin film or may be disposed between the resin film and the upper polarizing plate.
• Further, in the liquid crystal display of the second invention it is preferable that both first and second substrates be glass substrates. Even in the case of using glass substrates as the first and second substrates, the glass substrates can be made thin because a sufficient strength can be ensured by the resin film. Thus, it is possible to attain both the reduction in thickness of the liquid crystal display panel and ensuring of a sufficient strength.
• In connection with the liquid crystal display according to the present invention, in the liquid crystal display of the third invention (29), a resin film is affixed in contact with the back surface side of the lower polarizing plate of the liquid crystal display panel and the total thickness of both first and second substrates is 0.5 mm or less. In such a liquid crystal panel it is preferable that the thickness of the resin film be, for example, 0.1 mm or less and 0.3 mm or more. With such a thickness, when a pressing force is applied to the liquid crystal display panel from the upper polarizing plate side, the resin film can bear the force, the resin film being affixed to the back surface side of the display panel. Thus, even if the first and second substrates are made thin, it is possible to ensure a sufficient strength of the liquid crystal display panel.
• Also in the liquid crystal display of the third invention, the thickness of the first substrate and that of the second substrate may be almost equal to each other, or either one of the first or second substrates may be reduced in thickness.
• Moreover, in the liquid crystal display of the third invention, it is preferable that both first and second substrates be glass substrates. Even in the case of using glass substrates as the first and second substrates, it is possible to reduce the thickness of each glass substrate because a sufficient strength can be ensured by the resin film. Thus, it is possible to attain both the reduction in thickness of the liquid crystal display panel and ensuring of a sufficient strength.
• In connection with the liquid crystal display according to the present invention, in the liquid crystal display of the fourth invention (35), the resin film is disposed between the first substrate and the lower polarizing plate of the liquid crystal display panel and the total thickness of the first and second substrates is 0.5 mm or less. Also in this case it is preferable that the thickness of the resin film be, for example, 0.1 mm or more and 0.3 mm or less. According to this construction, the same effect can be obtained as in the liquid crystal display of the third invention.
• Also in the liquid crystal display of the fourth invention, the thickness of the first substrate and that of the second substrate may be almost equal to each other, or either one of the first or second substrates may be reduced in thickness.
• Moreover, in the liquid crystal display of the fourth invention it is preferable that both first and second substrates be glass substrates. Even in the case of using glass substrates as the first and second substrates it is possible to reduce the thickness of each glass substrate because a sufficient strength can be ensured by the resin film. Thus, it is possible to attain both thinning of the liquid crystal display panel and ensuring of a sufficient strength.
• In the case of installing the liquid crystal display of the third or the fourth invention into a mobile telephone terminal, it is preferable that a protective cover for protecting the liquid crystal display panel be affixed to a sheath of the mobile telephone terminal as in the conventional liquid crystal display. However, in the liquid crystal displays of third and fourth inventions, the total thickness of the first and second substrates is not larger than 0.5 mm and the thickness of the resin film is 0.1 mm or more and 0.3 mm or less. That is, in each of the liquid crystal displays of the third and fourth inventions, since the liquid crystal display panel is thinner than the conventional liquid crystal display panel, the thickness of the liquid crystal display can be so much reduced. Consequently, even if the protective cover for protecting the liquid crystal display panel is affixed to the sheath of the mobile telephone terminal, it is possible to reduce the thickness of the display unit of the mobile telephone terminal in comparison with the conventional counterpart.
• Although the first invention is concerned with a liquid crystal display, the same construction as the first invention is applicable to any display insofar as the display has a liquid crystal panel of a construction similar to the construction of the liquid crystal display panel used in the liquid crystal display. For example, even in the case of a display panel with a liquid crystal material not held between the first and second substrates, if an upper polarizing plate is disposed on the observer side with respect to the second substrate, both thinning of the liquid crystal panel and ensuring of a sufficient strength can be attained by affixing the resin film in contact with the upper polarizing plate. In this connection, if the surface pencil hardness of the resin film is 3 H or harder, then as is the case with the liquid crystal display of the first invention, for example when the liquid crystal display in question is installed into a mobile telephone terminal, it is no longer required to use a liquid crystal display panel protecting cover and hence it is possible to reduce the thickness of the display unit of the mobile telephone terminal. As an example of a display panel having a configuration similar to that of the liquid crystal display panel and not using any liquid crystal material, there is known a self-light emission type display panel using an organic EL.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG.1 is a schematic plan view showing a schematic configuration of a liquid crystal display panel according to a first embodiment of the present invention;
• FIG.2 is a sectional view taken along the line A-A′ ofFIG.1;
• FIGS.3A and3B are schematic sectional views for explaining a function and effect of the liquid crystal display panel of the first embodiment;
• FIG.4 is a schematic front view showing a schematic configuration of a display unit of a conventional mobile telephone terminal;
• FIG.5 is a sectional view taken along the line B-B′ ofFIG.4;
• FIG.6 is a schematic front view showing a schematic configuration of a display unit of a mobile telephone terminal using the liquid crystal display panel of the first embodiment;
• FIG.7 is a sectional view taken along the line C-C′ ofFIG.6;
• FIGS.8A and8B are schematic sectional views showing modified configurations of the display unit of the mobile telephone terminal using the liquid crystal display panel of the first embodiment;
• FIG.9 is a schematic front view for explaining an application example of the liquid crystal display panel of the first embodiment;
• FIG.10 is a sectional view taken along the line D-D′ ofFIG.9;
• FIGS.11A to11C are schematic sectional views showing structural examples of a display unit of a mobile telephone terminal using the liquid crystal display panel shown inFIGS.9 and10;
• FIG.12 is a schematic sectional view showing a schematic configuration of a liquid crystal display panel according to a second embodiment of the present invention;
• FIGS.13A to13C are schematic sectional views showing structural examples of a display unit of a mobile telephone terminal using the liquid crystal display panel of the second embodiment;
• FIG.14 is a schematic sectional view for explaining an application example of the liquid crystal display panel of the second embodiment;
• FIGS.15A to15C are schematic sectional views showing structural examples of a display unit of a mobile telephone terminal using the liquid crystal display panel shown inFIG.14;
• FIG.16 is a schematic sectional view showing a schematic configuration of a liquid crystal display panel according to a third embodiment of the present invention;
• FIG.17 is a schematic sectional view for explaining a modification of the liquid crystal display panel of the third embodiment;
• FIG.18 is a schematic sectional view showing a schematic configuration of a reflection type liquid crystal display panel to which the present invention is applied; and
• FIG.19 is a schematic sectional view showing a schematic configuration of an organic EL panel to which the present invention is applied.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
• The present invention will be described in detail by way of embodiments thereof and with reference to the accompanying drawings. In all of the drawings for illustration of the embodiments, portions having the same functions are identified by the same reference numerals, and repeated explanations thereof will be omitted.
First Embodiment
• FIG.1 is a schematic plan view showing a schematic configuration of a liquid crystal display panel according to a first embodiment of the present invention,FIG.2 is a sectional view taken along the line A-A′ ofFIG.1, andFIG.3 is a schematic sectional view for explaining a function and effect of the liquid crystal display panel of the first embodiment. InFIG.3 there are shown two sectional views asFIG.3A andFIG.3B, both of which correspond to the sectional configuration taken along the line A-A′ inFIG.1.
• In the first embodiment, a reference will be made to a transmission type liquid crystal display as an example of a display to which the present invention is applied, and a description will be given below about the configuration, as well as function and effect, of a liquid crystal display panel used in the transmission type liquid crystal display.
• As shown inFIG.1, the liquid crystal display panel of the first embodiment includes aTFT substrate1, acounter substrate2, aliquid crystal material3 held between theTFT substrate1 and thecounter substrate2, a pair ofpolarizing plates4,5 disposed between the TFT substrate and thecounter substrate2 both holding theliquid crystal material3, and aresin film6 affixed in contact with thepolarizing plate5 which is located on thecounter substrate2 side.
• TheTFT substrate1 and thecounter substrate2 are bonded together through anannular sealing member7 and theliquid crystal material3 is sealed and held within the space enclosed by theTFT substrate1,counter substrate2 and sealingmember7.
• In the display having such a liquid crystal display panel, when seen from an observer side, thecounter substrate2 is usually disposed on the observer side with respect to the TFT substrate. That is, when the liquid crystal display panel of the first embodiment is viewed from the observer side, theresin film6, polarizingplate5,counter substrate2,liquid crystal material3,TFT substrate1 andpolarizing plate4 are disposed in this order from the observer side. Therefore, in the following description, thepolarizing plate5 disposed on the observer side (front side) with respect to thecounter substrate2 when seen from the observer side will be designated the upper polarizing plate, while thepolarizing plate4 disposed on the back surface side (back side) of the TFT substrate will be designated the lower polarizing plate.
• TheTFT substrate1 includes aglass substrate101 and amulti-thin film layer102. Though detailed descriptions are omitted, themulti-thin film layer102 is a laminate of plural insulating layers, conductive layer, semiconductor layer and the like. For example, a scanning signal line (also called a gate signal line), a video signal line (also called a drain signal line), TFT and pixel electrodes are formed in themulti-thin film layer102.
• Thecounter substrate2 includes aglass substrate201 and amulti-thin film layer202. Though detailed descriptions are omitted, themulti-thin film layer202 is a laminate of plural insulating layers and conductive layer, forming a color filter for example.
• In the case where the driving method for the liquid crystal display panel is of a longitudinal electric field type, common electrodes are also formed in themulti-thin film layer202 of thecounter substrate2 and opposed to the pixel electrodes of theTFT substrate1. Where the driving method for the liquid crystal display panel is of a lateral electric field type, the common electrodes are formed in themulti-thin film layer102 of theTFT substrate1.
• Any of various combinations applied to conventional liquid crystal display panels may be adopted for the combination of the configuration of themulti-thin film layer102 of the TFT substrate and themulti-thin film layer202 of thecounter substrate2. Therefore, detailed descriptions on concrete structural examples of the multi-thin film layers102 and202 will be here omitted.
• The lowerpolarizing plate4 is affixed in contact with theglass substrate101 in theTFT substrate1 through a pressure-sensitive adhesive for example. Likewise, the upperpolarizing plate5 is also affixed in contact with theglass substrate201 of thecounter substrate2 through a pressure-sensitive adhesive for example. In this case, the upperpolarizing plate4 and the lowerpolarizing plate5 are affixed to the glass substrates in such a manner that their transmission axes (also called polarization axes) intersect each other perpendicularly or are parallel to each other. For the lowerpolarizing plate4 and the upperpolarizing plate5, for example, film-like polarizing plates used in conventional liquid crystal display panels may be used. Detailed descriptions on concrete structural examples of the material, etc. will be here omitted.
• In the liquid crystal display panel of the first embodiment, though not shown, a phase difference plate may be disposed between the glass substrate of theTFT substrate1 and the lowerpolarizing plate4 and also between theglass substrate201 of thecounter substrate2 and the upperpolarizing plate5.
• Theresin film6 is a film member disposed on the most front side when viewed from the observer side. Therefore, it is preferable that a film with a high light transmittance, especially a colorless, transparent film be used as theresin film6. For example, an acrylic resin film or an epoxy resin film may be used as theresin film6. Theresin film6 is affixed in contact with the upper polarizing plate through a pressure-sensitive adhesive for example.
• In the liquid crystal display panel of the first embodiment it is preferable that theresin film6 have a thickness, T6, of 0.2 mm or more and 1.0 mm or less. If the thickness T6 of theresin film6 is 0.2 mm or more, a sufficient strength of the liquid crystal panel can be ensured even if theglass substrate101 of the TFT substrate and theglass substrate201 of thecounter electrode2 are each made as thin as 0.5 mm or less. Therefore, in the liquid crystal display panel of the first embodiment, a sufficient strength can be ensured even if the total panel thickness, TP, is 2 mm or less. In the liquid crystal display panel of this embodiment it is preferable that the total panel thickness TP be not larger than 2 mm and the panel thickness, TP-T6, exclusive of the resin film be not larger than 1.3 mm.
• Since theresin film6 exhibits a function as a reinforcing member for the liquid crystal display panel, for example, as shown inFIG.3A, the thickness T2 of theglass substrate201 of thecounter substrate2 with theresin film6 affixed thereto can be made thinner than the thickness T1 of theglass substrate101 of theTFT substrate1. Consequently, the total panel thickness TP can be further reduced.
• In the case where the driving method for the liquid crystal display panel is of a lateral electric field type called IPS (In Plane Switching), for example, aconductor film203 for the prevention of electric charging may be provided on a back surface of theglass substrate201 of thecounter substrate2, in other words, on the surface to which the upperpolarizing plate5 is affixed, as shown inFIG.3B. In this case, the back surface of theglass substrate201 in thecounter substrate2 cannot be subjected to polishing for the reduction of thickness. When theconductor film203 is thus formed on the counter substrate, as shown inFIG.3B, a back surface of theglass substrate101 in the TFT substrate, in other words, the surface to which the lowerpolarizing plate4 is affixed, is ground to make the thickness T1 of theglass substrate101 in theTFT substrate1 smaller than the thickness T2 of theglass substrate201 in thecounter substrate2, whereby the total panel thickness TP can be reduced.
• Further, it is preferable that the surface hardness of theresin film6 be harder than that of the upperpolarizing plate5. More specifically, it is preferable for theresin film6 to have a surface pencil hardness of 3 H or harder. The surface pencil hardness is meant a hardness with which the material surface is damaged when a line is drawn on the material surface with a pencil. That is, the surface pencil hardness of 3 H means that the material surface is not damaged when a line is drawn on theresin film6 with a pencil having a hardness of 3 H or softer.
• To make theresin film6 with a surface pencil hardness of 3 H or harder, there may be used a film obtained by forming a material having a pencil hardness of 3 H or harder into a film shape, or there may be adopted a method wherein a material having an arbitrary pencil hardness is formed into a film and then the surface of the film is subjected to a hard coating treatment so as to give a surface pencil hardness of 3 H or harder. In the case of using an acrylic resin or epoxy resin as the material of theresin film6, the resin surface is subjected to a hard coating treatment as in the latter method just referred to above to give a surface pencil hardness of 3 H or harder.
• FIGS.4 to7 are schematic diagrams for explaining an example and functional effects of a hand-held electronic device for which the use of the liquid crystal display panel of the first embodiment is preferred.
• FIG.4 is a schematic front view showing a schematic configuration of a display unit of a conventional mobile telephone terminal,FIG.5 is a sectional view taken along the line B-B′ ofFIG.4,FIG.6 is a schematic front view showing a schematic configuration of a display unit of a mobile telephone terminal using the liquid crystal display panel of the first embodiment, andFIG.7 is a sectional view taken along the line C-C′ ofFIG.6.
• The liquid crystal display panel of the first embodiment is a display panel which is preferably applied to a display of a hand-held electronic device such as, for example, a mobile telephone terminal.
• The liquid crystal display used in the display unit of the mobile telephone terminal includes, in addition to the liquid crystal display panel, a data driver which outputs a video signal to a video signal line (drain line) in the liquid crystal display panel, a gate driver which outputs a scanning signal to a scanning signal line (gate line) in the liquid crystal display panel, and a timing controller for controlling the timing at which the video signal and the scanning signal are to be outputted. In the case of a transmission type or semi-transmission type liquid crystal display, the liquid crystal display has a back light (light source). These parts are held integrally by a frame member called a display mold for example.
• A liquid crystal display panel used in a conventional mobile telephone terminal includes, for example as shown inFIGS.4 and5, aTFT substrate1, acounter substrate2, a lowerpolarizing plate4, an upperpolarizing plate5, and a sealingmember7. When the liquid crystal display panel is seen by the observer, the upperpolarizing plate5,counter substrate2,liquid crystal material3,TFT substrate1 and lowerpolarizing plate4 are disposed in this order from the observer. If the liquid crystal display concerned is a transmission type display, aback light8 is disposed further behind the lowerpolarizing plate4 when seen from the observer side. The liquid crystal display panel and theback light8 are held by aconcave display mold9 so that a back surface side of theback light8 is a bottom surface.
• Such a liquid crystal display is accommodated within a sheath (case)10 having an opening of the mobile telephone terminal so that a display area DA of the liquid crystal display panel can be seen. In the conventional mobile telephone terminal, a transparentprotective cover11 constituted by an acrylic plate or the like is usually disposed at a position closer to the observer compared with the liquid crystal display panel. In many cases, theprotective cover11 is fitted in a depression formed in the surface of thesheath10 and is affixed to thesheath10 through a pressure-sensitive adhesive12. For example, theprotective cover11 functions to prevent the surface (upper polarizing plate5) of the liquid crystal display panel from being damaged or prevent the liquid crystal display panel from being cracked upon exertion of pressure on the liquid crystal display panel.
• In the conventional mobile telephone terminal using the liquid crystal display, it is necessary to use theprotective cover11 for protecting the liquid crystal display panel. Thus, the thickness of the display unit is increased.
• On the other hand, in the liquid crystal display panel of the first embodiment, theresin film6 is affixed to the upperpolarizing plate5 to enhance the strength of the liquid crystal display panel, and theresin film6 with a surface pencil hardness of 3 H or harder makes it difficult to damage the surface of theresin film6. That is, in the liquid crystal display panel of the first embodiment, theresin film6 is endowed with the function of the conventionalprotective cover11. Therefore, for example as shown inFIGS.6 and7, if the liquid crystal display wherein the liquid crystal display panel is disposed so that theresin film6 is positioned closest to the observer is accommodated inside thesheath10 of the liquid crystal display, the liquid crystal display panel can be protected from being damaged and cracked due to pressure even in the absence of theprotective cover11. As a result, the display unit of the mobile telephone terminal can be made thinner than the conventional counterpart.
• In the display unit of the conventional mobile telephone terminal there is an air layer between the liquid crystal display panel and theprotective cover11, but the air layer can be eliminated by using the liquid crystal display panel of the first embodiment. Consequently, the display efficiency can also be improved over conventional displays.
• In the liquid crystal display panel of the first embodiment, the TFT substrate and thecounter substrate2 can be fabricated usingglass substrates101 and201. Therefore, themultiple wiring layers102 and202 can be formed more easily than in the liquid crystal display panel using plastic substrates which is described inPatent Document 1. Besides, by forming theTFT substrate1 and thecounter substrate2 with use of theglass substrates101 and201, it is also possible to prevent the occurrence of unevenness in display caused by a change in environment.
• FIGS.8A and8B is schematic sectional views showing modified configurations of the display unit of the mobile telephone terminal using the liquid crystal display panel of the first embodiment. InFIG.8, as such modified configurations, there are shown two sectional views which areFIG.8A andFIG.8B. These two sectional views correspond to the sectional configuration taken along the line C-C′ ofFIG.6.
• When the liquid crystal display having the liquid crystal panel of the first embodiment is applied to a mobile telephone terminal, it is not necessary to affix theprotective cover11 to the surface of thesheath10, as shown inFIG.7.
• However, when the liquid crystal display is accommodated in such a state as shown inFIG.7, water or the like is apt to get into the inside of the sheath through a gap formed between anouter periphery10A of the opening area of thesheath10 and the liquid crystal display panel (resin film6). As a result, wiring formed on theTFT substrate1 of the liquid crystal display panel and wiring formed on another circuit board are apt to be corroded.
• Therefore, in the case of using the liquid crystal display panel of the first embodiment, for example as shown inFIG.8A, it is preferable that the outline of both upperpolarizing plate5 andresin film6 affixed to thecounter substrate2 be made smaller than that of the lowerpolarizing plate4 and that thecounter substrate2 and thesheath10 be fixed together by bonding with use of a pressure-sensitive adhesive13. In this case, if the pressure-sensitive adhesive13 is formed in an annular shape which surrounds the upperpolarizing plate5 and theresin film6, the pressure-sensitive adhesive13 serves as a wall and it is possible to prevent the entry of water or the like into the inside of the sheath. Of course, an adhesive may be used instead of the pressure-sensitive adhesive13.
• For example as shown inFIG.8B, if a projecting portion projecting toward thecounter substrate2 is formed on theouter periphery10A of the opening area of thesheath10, the effect of preventing the entry of water or the line to the inside of the sheath is further enhanced.
• FIG.9 is a schematic front view for explaining an application of the liquid crystal display panel of the first embodiment andFIG.10 is a sectional view taken along the line D-D′ ofFIG.9.
• In the liquid crystal display panel of the first embodiment, both reduction in thickness of the panel and ensuring of a sufficient strength thereof are attained by affixing theresin film6 to the upperpolarizing plate5 affixed to thecounter substrate2. Further, by using such a liquid crystal display panel it is made possible to reduce the thickness of a hand-held electronic device such as a mobile telephone terminal.
• However, in the case where the outer periphery of the upperpolarizing plate5 and that of theresin film6 are coincident with each other when seen from the front side for example as is the case with the liquid crystal display panel shown inFIGS.1 and2, the outer periphery end face of the upperpolarizing plate5 comes into contact with the outside air for example as shown inFIG.7 andFIGS.8A and8B. Consequently, the upperpolarizing plate5 is corroded and deteriorated due to moisture contained in the outside air and there is a possibility that the upperpolarizing plate5 may be peeled off from thecounter substrate2 or unevenness in display may result.
• The occurrence of such a problem can be prevented by diminishing the outline of theresin film6 so that the outer periphery of theresin film6 lies inside the outer periphery of the upperpolarizing plate5 when the liquid crystal display panel is viewed from the front side for example as shown inFIGS.9 and10. Of course, the outline of theresin film6 should be diminished in such a manner that the outer periphery thereof lies outside the display area DA.
• FIGS.11A to11C are schematic sectional views showing structural examples of a display unit of a mobile telephone terminal using the liquid crystal display panel shown inFIGS.9 and10. InFIG.11, there are shown three sectional views11A,11B and11C as structural examples, which sectional views correspond to the sectional configuration taken along the line C-C′ ofFIG.6.
• Also in the case where the liquid crystal display having the liquid crystal display panel shown inFIGS.9 and10 is applied to a mobile telephone terminal, it is not necessary to affix theprotective cover11 to the surface of thesheath10 for example as shown inFIG.11A. Consequently, the display unit of the mobile telephone terminal can be made thinner than the conventional counterpart.
• Besides, since the outer periphery of theresin film6 in the liquid crystal display panel lies inside the outer periphery of the upperpolarizing plate5, theouter periphery10A of the opening area of thesheath10 can be positioned inside the outer periphery of the upperpolarizing plate5. Therefore, for example in comparison with the case ofFIG.7, the path from the outside of thesheath10 up to a side face of the outer periphery of the upperpolarizing plate5 becomes long and complicated and the entry of moisture, etc. becomes difficult. As a result, the side face of the outer periphery of the upperpolarizing plate5 becomes difficult to be corroded and deteriorated and it is possible to diminish the possibility of the upperpolarizing plate5 being peeled off from thecounter substrate2 or causing unevenness in display.
• For example as shown inFIG.11B, it is preferable that the upperpolarizing plate5 and thesheath10 be bonded and fixed together using a pressure-sensitive adhesive13. In this case, if the shape of the pressure-sensitive adhesive13 is made an annular shape which surrounds theresin film6, the pressure-sensitive adhesive13 serves as a wall and it is thereby possible to prevent the entry of moisture, etc. into inside of the sheath. As a result, the side face of the outer periphery of the upperpolarizing plate5 becomes more difficult to be deteriorated and it is possible to further diminish the possibility of the upperpolarizing plate5 being peeled off from thecounter substrate2 or causing unevenness in display.
• Moreover, for example as shown inFIG.11C, if theouter periphery10A of the opening area of thesheath10 is formed with a projecting portion projecting toward the upperpolarizing plate5, the effect of preventing the entry of moisture, etc. into the inside of the sheath is more enhanced.
• According to the liquid crystal display panel of the first embodiment, as set forth above, a required strength of the liquid crystal display panel can be ensured by affixing theresin film6 in contact with the upperpolarizing plate5. As a result, the thickness of theglass substrate10 in theTFT substrate1 and that of theglass substrate201 in thecounter substrate2 can be reduced by polishing. Consequently, it is possible to reduce the thickness of the liquid crystal display panel. That is, in the liquid crystal display panel of the first embodiment it is possible to attain both reduction of thickness and ensuring of a sufficient strength.
• Further, since theTFT substrate1 and thecounter substrate2 can each be formed using a glass substrate, there is little difference in the amount of deformation caused by an environmental change. Therefore, it is also possible to prevent the occurrence of unevenness in display caused by an environmental change.
• Additionally, by applying the liquid crystal display (module) having the liquid crystal display panel of the first embodiment to a hand-held electronic device such as a mobile telephone terminal it is possible to reduce the thickness of a display unit of the hand-held electronic device.
• In the first embodiment, a reference is made to an example in which the surface pencil hardness of theresin film6 is set to 3 H or harder, whereby for example the use of the conventionalprotective cover11 is made unnecessary when installing the liquid crystal display into the mobile telephone terminal and the thickness of the display unit is thereby reduced. However, the application of the liquid crystal display panel of the first embodiment is not limited to such an example. For example, it goes without saying that the liquid crystal display panel of the first embodiment may be installed into a mobile telephone terminal using theprotective cover11. In the case of using theprotective cover11, the surface pencil hardness of theresin film6 may be 3 H or softer. In this case, however, it is preferable the total thickness TP of the liquid crystal display panel including theresin film6 be set to a value of 1.3 mm or less.
Second Embodiment
• FIG.12 is a schematic sectional view showing a schematic configuration of a liquid crystal display panel according to a second embodiment of the present invention. The sectional view ofFIG.12 corresponds to the sectional configuration taken along the line A-A′ ofFIG.1.
• The liquid crystal display panel of the second embodiment is basically of the same configuration as the liquid crystal display panel of the first embodiment. In the second embodiment, therefore, a description will be given below about only the difference from the first embodiment.
• For example as shown inFIG.12, the liquid crystal display panel of the second embodiment includes aTFT substrate1, acounter substrate2, aliquid crystal material3 held between theTFT substrate1 and thecounter substrate2, a pair of polarizing plates (a lowerpolarizing plate4 and an upper polarizing plate5) disposed between theTFT substrate1 and thecounter substrate2 both holding theliquid crystal material3, and aresin film6 disposed on thecounter substrate2 side.
• Also in the liquid crystal display panel of the second embodiment, though not shown, a phase difference plate may be disposed between aglass substrate101 in theTFT substrate1 and the lowerpolarizing plate4 and also between aglass substrate201 in thecounter substrate2 and the upperpolarizing plate5.
• In this case, unlike the first embodiment, theresin film6 is disposed between thecounter substrate2 and the upperpolarizing plate5. For example, theresin film6 is affixed in contact with theglass substrate201 in thecounter substrate2 through a pressure-sensitive adhesive or the like. Further, the upperpolarizing plate5 is affixed in contact with theresin film6 through a pressure-sensitive adhesive for example.
• Also in the liquid crystal display panel of the second embodiment it is preferable that a film of a high light transmittance, especially a colorless, transparent film, be used as theresin film6. In the liquid crystal panel of the second embodiment theresin film6 is disposed between the upperpolarizing plate5 and the counter substrate2 (lower polarizing plate4). Therefore, it is preferable for theresin film6 to be low, more preferably nearly zero, in optical anisotropy. Therefore, it is preferable to use an epoxy resin as the material of theresin film6. However, in the case where the optical anisotropy is of an allowable magnitude or can be compensated, an acrylic resin for example may be used as the material of theresin film6.
• In the liquid crystal display panel of the second embodiment, the upperpolarizing plate5 is disposed on the observer side (front side) with respect to theresin film6. Therefore, in the second embodiment, unlike the first embodiment, it is not necessary to set the surface pencil hardness of theresin film6 to 3 H or harder. Instead, in the liquid crystal display panel of the second embodiment, the surface pencil hardness of the upperpolarizing plate5 positioned closest to the observer is made 3 H or harder. This can be done for example by applying a hard coating treatment to the surface of a conventional polarizing plate.
• Also in the liquid crystal display panel of the second embodiment it is preferable that the thickness T6 of theresin film6 be set to a value of 0.2 mm or more and 1.0 mm or less. If the thickness T6 of theresin film6 is not smaller than 0.2 mm, it is possible to ensure a sufficient strength of the liquid crystal display panel even if theglass substrate101 in theTFT substrate1 and theglass substrate201 in thecounter substrate2 are made as thin as 0.5 mm or less. In the liquid crystal display panel of the second embodiment, therefore, it is possible to ensure a sufficient strength even if the total panel thickness TP is made 2 mm or less. In the liquid crystal display panel of the second embodiment it is preferable that the total panel thickness TP be 2 mm or less and that the panel thickness TP-T6 exclusive of the resin film be 1.3 mm or less.
• Theresin film6 also functions as a reinforcing member for the liquid crystal display panel and therefore, as in the configuration shown inFIG.3A, the thickness T2 of theglass substrate201 in thecounter substrate2 with theresin film6 affixed thereto can be made smaller than the thickness T1 of theglass substrate101 in theTFT substrate1. Consequently, the total panel thickness TP can be further reduced.
• When the liquid crystal display panel is of the lateral electric field driving type called IPS, for example as in the configuration shown inFIG.3B, there sometimes is a case where aconductor film203 for the prevention of electric charging is provided on the back surface of theglass substrate201 in thecounter substrate2, in other words, the surface with the upperpolarizing plate5 affixed thereto. In this case, theglass substrate201 in thecounter substrate2 cannot be subjected to polishing for the reduction of thickness. Therefore, when theconductor film203 is provided on thecounter substrate2, for example as in the configuration shown inFIG.3B, the back surface of theglass substrate101 in the TFT substrate, in other words, the surface with the lowerpolarizing plate4 affixed thereto, is subjected to polishing to make the thickness T1 of theglass substrate101 in theTFT substrate1 smaller than the thickness T2 of theglass substrate201 in thecounter substrate2, whereby the total panel thickness TP can be reduced.
• FIGS.13A to13C are schematic sectional views showing structural examples of a display unit of a mobile telephone terminal using the liquid crystal display panel of the second embodiment. InFIG.13 there are shown three sectional views13A,13B and13C as structural examples, which correspond to the sectional configuration taken along the line C-C′ ofFIG.6.
• Also in the case of applying the liquid crystal display having the liquid crystal display panel of the second embodiment to a mobile telephone terminal, it is not necessary to affix theprotective cover11 to the surface of asheath10 for example as shown inFIG.13A. Consequently, the display unit of the mobile telephone terminal can be made thinner than the conventional counterpart.
• However, when the liquid crystal display is accommodated inside thesheath10 in such a state as shown inFIG.13A, moisture or the like is apt to get into the inside of thesheath10 through a gap formed between anouter periphery10A of the opening area of thesheath10 and the liquid crystal display panel (upper polarizing plate5), so that wiring formed in theTFT substrate1 of the liquid crystal display panel and wiring formed in another circuit board are apt to be corroded.
• Therefore, also in the case of using the liquid crystal display panel of the second embodiment, for example as shown inFIG.13B, it is preferable that the outline of the upperpolarizing plate5 and theresin film6 both affixed to thecounter substrate2 be made smaller than that of the lowerpolarizing plate4 and that thecounter substrate2 and the sheath be bonded and fixed together through a pressure-sensitive adhesive13. In this case, if the pressure-sensitive adhesive13 is formed in an annular shape which surrounds the upperpolarizing plate5 and theresin film6, the pressure-sensitive adhesive13 serves as a wall, whereby the entry of moisture, etc. into the inside of the sheath can be prevented.
• Moreover, for example as shown inFIG.13C, if theouter periphery10A of the opening area of thesheath10 is formed with a projecting portion projecting toward thecounter substrate2, the effect of preventing the entry of moisture, etc. into the inside of the sheath is further enhanced.
• FIG.14 is a schematic sectional view for explaining an application of the liquid crystal display panel of the second embodiment, which corresponds to the sectional configuration taken along the line D-D′ ofFIG.9.
• Also in the liquid crystal display panel of the second embodiment, theresin film6 and the upperpolarizing plate5 are both affixed to theglass substrate201 of thecounter substrate2, and the outline of the upperpolarizing plate5 may be made small so that the outer periphery thereof lies inside the outer periphery of theresin film6, as shown inFIG.14. In this case, it goes without saying that the outer periphery of the upperpolarizing plate5 should lie outside the display area DA.
• FIGS.15A to15C are schematic sectional views showing structural examples of a display unit of a mobile telephone terminal using the liquid crystal display panel shown inFIG.14. InFIG.15, there are shown three sectional views15A,15B and15C as structural examples, which correspond to the sectional configuration taken along the line C-C′ ofFIG.6.
• Also in the case of applying the liquid crystal display using the liquid crystal display panel shown inFIG.14 to a mobile telephone terminal, for example as shown inFIG.15A, it is not necessary to affix theprotective cover11 to the surface of thesheath10, whereby the display unit of the mobile telephone terminal can be made thinner than the conventional counterpart.
• Moreover, since the outer periphery of the upperpolarizing plate5 of the liquid crystal display panel lies inside the outer periphery of theresin film6, theouter periphery10A of the opening area of thesheath10 can be positioned inside the outer periphery of theresin film6. Consequently, for example in comparison with the case ofFIG.13A, the path from the outside of thesheath10 to the inside thereof becomes long and complicated, making the entry of moisture, etc. difficult.
• In this case, it is preferable that the resin film and thesheath10 be bonded and fixed together using the pressure-sensitive adhesive13, for example as shown inFIG.15B. If the pressure-sensitive adhesive13 is formed for example in an annular shape which surrounds the upper polarizing plate, the pressure-sensitive adhesive13 serves as a wall, whereby it is possible to prevent the entry of moisture, etc. into the inside of the sheath.
• Further, for example as shown inFIG.15C, if theouter periphery10A of the opening area of theouter sheath10 is formed with a projecting portion projecting toward theresin film6, the effect of preventing the entry of moisture, etc. into the inside of the sheath is further enhanced.
• According to the liquid crystal display panel of the second embodiment, since theresin film6 is disposed between and in close contact with theglass substrate101 in theTFT substrate1 and theglass substrate201 in thecounter substrate2, it is possible to ensure a required strength of the liquid crystal display panel. As a result, bothglass substrates101 and201 can be reduced in thickness by polishing and hence it is possible to reduce the thickness of the liquid crystal display panel. That is, also in the liquid crystal display panel of the second embodiment it is possible to attain both reduction of thickness and ensuring of a sufficient strength.
• Further, since theTFT substrate1 and thecounter substrate2 can be formed using glass substrates, there is little difference in the amount of deformation caused by an environmental change. Consequently, it is also possible to prevent the occurrence of unevenness in display caused by an environmental change.
• Additionally, the display unit of a hand-held electronic device such as a mobile telephone terminal can be made thin by applying the liquid crystal display (module) having the liquid crystal display panel of the second embodiment to the hand-held electronic device.
• In the second embodiment reference is made to an example in which the surface pencil hardness of the upperpolarizing plate5 is made 3 H or harder, thereby making the use of the conventionalprotective cover11 unnecessary when installing the liquid crystal display into the mobile telephone terminal to attain the reduction in thickness of the display unit. However, it goes without saying that the application of the liquid crystal display panel of the second embodiment is not limited to this example, and the liquid crystal display panel may be installed into a mobile telephone terminal using theprotective cover11. In the case of using theprotective cover11, the surface pencil hardness of the upperpolarizing plate5 may be 3 H or softer. In this case, however, it is preferable that the total thickness TP of the liquid crystal display panel including theresin film6 be set to a value of 1.3 mm or less.
Third Embodiment
• FIG.16 is a schematic sectional view showing a schematic configuration of a liquid crystal display panel according to a third embodiment of the present invention.
• The liquid crystal display panel of the third embodiment is basically of the same configuration as the liquid crystal display panel of the first embodiment. In the third embodiment, therefore, a description will be given only about points different from the first embodiment.
• For example as shown inFIG.16, the liquid crystal display panel of the third embodiment includes aTFT substrate1, acounter substrate2, aliquid crystal material3 held between the TFT substrate and thecounter substrate2, a pair of polarizing plates (a lowerpolarizing plate4 and an upper polarizing plate5) disposed between theTFT substrate1 and thecounter substrate2 both holding theliquid crystal material3, and aresin film6 affixed in contact with the lowerpolarizing plate4 located on theTFT substrate1 side.
• That is, in the liquid crystal display panel of the third embodiment, unlike the first embodiment, theresin film6 is disposed lies on the back surface side of theTFT substrate1 and is most distant from the observer. Theresin film6 is affixed in contact with the lowerpolarizing plate4 with use of a pressure-sensitive adhesive for example.
• Also in the liquid crystal display panel of the third embodiment, though not shown, a phase difference plate may be disposed between aglass substrate101 in the TFT substrate and the lowerpolarizing plate4 and also between aglass substrate201 of thecounter substrate2 and the upperpolarizing plate5.
• Also in the liquid crystal display panel of the third embodiment it is preferable that a film of a high light transmittance, especially a colorless, transparent film, be used as theresin film6. For example, an acrylic resin or an epoxy resin may be used as theresin film6.
• In the liquid crystal display panel of the third embodiment, the lowerpolarizing plate4 and theTFT substrate1 are disposed more closely to (in front of) the observer with respect to theresin film6. Therefore, also in the third embodiment, unlike the liquid crystal display panel of the first embodiment, it is not necessary to set the surface pencil hardness of theresin film6 to 3 H or harder.
• In the liquid crystal display panel of the third embodiment, for example, it is preferable that the total of the thickness T1 of theglass substrate101 in theTFT substrate1 and the thickness T2 of theglass substrate201 in thecounter substrate2 be 0.5 mm or less. The thicknesses T1 and T2 of theglass substrates101 and201 may be approximately equal to each other, or either one of them may be thin and the other thick.
• As a result, when a pressing force is exerted on the liquid crystal display panel from the upperpolarizing plate5 side, the force can be borne by theresin film6 affixed to the back surface of the liquid crystal display panel. Therefore, even if theglass substrates101 and201 are made thin, it is possible to ensure a sufficient strength of the liquid crystal display panel.
• FIG.17 is a schematic sectional view for explaining a modified example of the liquid crystal display panel of the third embodiment.
• In the case of disposing theresin film6 on theTFT substrate1 side as in the third embodiment, the disposed position may be between theglass substrate101 in theTFT substrate1 and the lowerpolarizing plate4 as inFIG.17. In the case of disposing theresin film6 between theTFT substrate1 and the lowerpolarizing plate4, it is preferable that theresin film6 be low, more preferably nearly zero, in optical anisotropy. Therefore, it is preferable to use, for example, an epoxy resin as the material of theresin film6. However, if the optical anisotropy is of an allowable magnitude or can be compensated, for example an acrylic resin may be used as the material of theresin film6.
• Also in the liquid crystal display panel of the third embodiment it is preferable that the thickness T6 of theresin film6 be set to 0.2 mm or more and 1.0 mm or less. If the thickness T6 of theresin film6 is 0.2 mm or more, a sufficient strength of the liquid crystal display panel can be ensured even if theglass substrate101 in theTFT substrate1 and theglass substrate201 in thecounter substrate2 are each made as thin as 0.5 mm or less. Thus, in the liquid crystal display panel of the third embodiment, a sufficient strength can be ensured even if the total panel thickness TP is set to 1.3 mm or less.
• According to the liquid crystal display panel of the third embodiment, as set forth above, a required strength of the liquid crystal display panel can be ensured by disposing theresin film6 in a contact manner on the back surface side of the lowerpolarizing plate4 or between theglass substrate101 in theTFT substrate1 and the lowerpolarizing plate4. Besides, since the required strength can be ensured by theresin film6, theglass substrate101 in theTFT substrate1 and theglass substrate201 in thecounter substrate2 can be reduced in thickness by polishing. Consequently, it is possible to reduce the thickness of the liquid crystal display panel. That is, also in the liquid crystal display panel of the third embodiment it is possible to attain both reduction of thickness and ensuring of a sufficient strength.
• Moreover, since theTFT substrate1 and thecounter substrate2 can be formed using glass substrates, there is little difference in the amount of deformation caused by an environmental change. Therefore, it is possible to prevent the occurrence of unevenness in display caused by an environmental change.
• In the case of installing the liquid crystal display having the liquid crystal display panel of the third embodiment to, for example, a mobile telephone terminal, it is preferable, as in the conventional liquid crystal display, that a protective cover for protecting the liquid crystal display panel be affixed to asheath10 of the mobile telephone terminal. However, in the liquid crystal display having the liquid crystal display panel of the third embodiment, the total of the thickness T1 of theglass substrate101 in theTFT substrate1 and the thickness T2 of theglass substrate201 in thecounter substrate2 is 0.5 mm or less and the thickness of the resin film is 0.1 mm or more and 0.3 mm or less. That is, in the liquid crystal display using the liquid crystal display panel of the third embodiment, the liquid crystal display panel is thinner than the conventional liquid crystal display panel and can be so much reduced in thickness. As a result, even if the protective cover for protecting the liquid crystal display panel is affixed to the sheath of the mobile telephone terminal, the display unit of the mobile telephone terminal can be made thinner than the conventional counterpart.
• Although the present invention has been described concretely on the basis of the above embodiments, it goes without saying that the invention is not limited to the above embodiments, but that various changes may be made within the scope not departing from the gist of the invention.
• For example, in each of the above embodiments, reference is made to a transmission type or semi-transmission type liquid crystal display panel as an example, which has two polarizing plates, i.e., the lowerpolarizing plate2 and the upperpolarizing plate5. However, the present invention is applicable not only to such a transmission or semi-transmission type but also to a reflection type liquid crystal display panel.
• FIG.18 is a schematic sectional view showing a schematic configuration wherein the present invention is applied to a reflection type liquid crystal display panel.
• For example as shown inFIG.18, the reflection type liquid crystal display panel includes aTFT substrate1, acounter substrate2, aliquid crystal material3 held between the TFT substrate and thecounter substrate2, and apolarizing plate5 affixed to aglass substrate201 in thecounter substrate2. In the case of applying the configuration of the first embodiment to this display panel, there is provided aresin film6 affixed in contact with thepolarizing plate5 which is disposed on thecounter substrate2 side.
• When the display having such a liquid crystal display panel is viewed from the observer side, thecounter substrate2 is usually disposed on the observer side with respect to theTFT substrate1. That is, when the observer looks at the liquid crystal display panel shown inFIG.18, theresin film6, polarizingplate5,counter substrate2,liquid crystal material3 andTFT substrate1 are disposed in this order from the observer side.
• In this case, for example a reflective layer is formed in amulti-thin film layer102 of theTFT substrate1 and light incident on the liquid crystal display panel from theresin film6 side is reflected by the reflective layer in themulti-thin film layer102 and is then emitted toward the observer.
• Even in such a reflection type liquid crystal display panel, by affixing theresin film6 formed of, for example, an acrylic resin or an epoxy resin to thepolarizing plate5 in a contact manner, it is possible to ensure a sufficient strength even if theglass substrate101 in theTFT substrate1 and theglass substrate201 in thecounter substrate2 are reduced in thickness by polishing. Thus, it is possible to attain both reduction in thickness of the liquid crystal display panel and ensuring of a sufficient strength.
• FIG.18 shows an example in which theresin film6 is disposed more closely to the observer compared with thepolarizing plate5 However, this configuration is not limited, and theresin film6 may be affixed between theglass substrate201 in thecounter substrate2 and thepolarizing plate5 or to the back surface of theglass substrate101 in theTFT substrate1.
• Although in each of the above embodiments reference is made to an example in which the present invention is applied to a liquid crystal display panel, the present invention is applicable also to other display panels, e.g., a display panel in a self-light emission type display using organic EL (Electro Luminescence).
• FIG.19 is a schematic sectional view showing a schematic configuration in which the present invention is applied to an organic EL panel.
• For example as shown inFIG.19, the organic EL panel includes aTFT substrate1, a counter substrate2 (glass substrate201), as well as aphase difference plate15 and an upperpolarizing plate5 both affixed to thecounter substrate2. In the case of applying the configuration of the first embodiment to this panel, there is provided aresin film6 affixed in contact with the upperpolarizing plate5 which is disposed on thecounter substrate2 side.
• In the organic EL panel, the upperpolarizing plate5 and aphase difference plate15 are combined together to form a circularly polarizing plate, thereby preventing extraneous light from being reflected (preventing extraneous light from entering an image display area in the display panel). For thephase difference plate15, for example, only a quarter-wave phase difference plate may be used, or both a quarter-wave phase difference plate and a half-wave phase difference plate may be used in a stacked fashion. In particular, A combination of the upperpolarizing plate5 with aphase difference plate15 having the quarter-wave phase difference plate and the half-wave phase difference plate stacked makes it possible to form a wide-band circularly polarizing plate.
• In the organic EL panel, for example a light emitting layer using an organic EL material is provided in themulti-thin film layer102 of theTFT substrate1 and the gradation of each pixel is controlled by turning ON and OFF of the light emitting layer and by the luminance of light14 during turning ON of the light emitting layer. Therefore, the space enclosed with theTFT substrate1,counter substrate2 and sealingmember7 is in a vacuum state. Further, unlike the liquid crystal display panel, amulti-thin film layer202 may be absent in thecounter substrate2.
• It goes without saying that the present invention is applicable not only to the liquid crystal display panel and the display panel using organic EL, but also to display panels similar in configuration to those panels.

Claims (13)

What is claimed is:

1. A display device used in a hand-held electronic device comprising:

a TFT substrate;

a counter substrate fixed to the TFT substrate with a seal member, the counter substrate including a glass substrate and a multi-thin film layer on the glass substrate;

a first polarizing plate provided on the TFT substrate;

a second polarizing plate provided on the counter substrate;

a protective member provided on the second polarizing plate with an adhesive; and

a back light fixed to the first polarizing plate with a fixing member,

wherein

the protective member is a protective cover of the hand-held electronic device and overlaps at least the seal member and the multi-thin film layer.

2. The display device according toclaim 1, wherein

a thickness of one of the TFT substrate and the counter substrate is no greater than 0.5 mm.

3. The display device according toclaim 1, wherein

the first polarizing plate has a first surface and a second surface, which is opposite to the first surface, and

the first surface of the first polarizing plate is adhered to the TFT substrate.

4. The display device according toclaim 3, wherein

the protective member has a first surface and a second surface opposite the first surface, and the second surface is opposed to the second polarizing plate, and

a thickness from the second surface of the first polarizing plate to the first surface of the protective member is no greater than 2 mm .

5. The display device according toclaim 1, wherein

no air layer is formed between the second polarizing plate and the protective member in a display region.

6. The display device according toclaim 1, wherein

wherein a thickness of the protective member is between 0.2 mm and 1.0 mm.

7. The display device according toclaim 1,

wherein a surface pencil hardness of the protective member is at least 3 H.

8. The display device according toclaim 1, wherein

an edge of the protective member overlaps the seal member and the multi-thin film layer.

9. The display device according toclaim 1, wherein

an edge of the multi-thin film layer coincides with a side of the glass substrate in a plan view.

10. The display device according toclaim 1, wherein

an edge of the second polarizing plate overlaps the seal member and the multi-thin film layer.

11. The display device according toclaim 1, wherein

an edge of the second polarizing plate coincides with an edge of the protective member in a plan view.

12. The display device according toclaim 1, further comprising

a conductor film disposed between the glass substrate and the second polarizing plate.

13. The display device according toclaim 12,

wherein an edge of the conductor film coincides with an edge of the glass substrate in a plan view.

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