Disclosure of Invention
The technical problem underlying the present invention is to provide an optical film for a light guide plate, which reduces or avoids the aforementioned problems.
Specifically, the technical problem to be solved by the present invention is to provide an optical film for a light guide plate, which can make the emergent light uniform by attaching the optical film on the surface of the light guide plate without changing the structure of the existing light guide plate without patterns, thereby eliminating the defect of uneven brightness of the liquid crystal display, saving the production and assembly costs, and improving the display effect.
the optical film sheet is attached to the side face of a non-pattern light guide plate of a backlight module of a liquid crystal display and comprises a transparent base material film, a plurality of prism columns which are arranged in parallel and have isosceles trapezoid cross sections are formed on the base material film, an LED light source is arranged on at least one side edge of the non-pattern light guide plate perpendicular to the length direction of the prism columns, the side length of the isosceles trapezoid cross section of each prism column, which is adjacent to the upper bottom edge of the base material film, is a, the side length of the isosceles trapezoid cross section of each prism column, which is far away from the lower bottom edge of the base material film, is b, wherein a is larger than b, the optical film sheet is bonded to the side face of the non-pattern light guide plate through an adhesive layer, the adhesive layer is composed of a thermosetting polymer or an ultraviolet curing polymer, the thermal expansion coefficient of the non-pattern light guide plate is smaller than that of the prism columns, the thermal expansion coefficient of the prism columns is smaller than that of the adhesive layer, the interval between adjacent prism columns close to the LED light source is larger than the interval between adjacent prism columns far away from the LED light source, the ultraviolet curing polymer, the included angle between the isosceles prism columns and the straight line perpendicular to the upper edge of.
The optical film for the light guide plate with the structure of the invention provides a backlight which can make the brightness of the whole display uniform and eliminate the defect of non-uniform brightness of the liquid crystal display by attaching the optical film with the specific pattern structure of the invention on the surface of the light guide plate without changing the structure of the existing light guide plate without patterns.
Detailed Description
In order to more clearly understand the technical features, objects, and effects of the present invention, embodiments of the present invention will now be described with reference to the accompanying drawings. Wherein like parts are given like reference numerals.
Based on the defects that the scheme of patterning the surface of the light guide plate by adopting a printing or laser forming mode in the prior art has high production and assembly cost, cannot provide a high-quality light guide plate, and is easy to cause the cost rise of a display and the reduction of the display effect due to the poor light guide plate, the invention provides the optical membrane suitable for the non-pattern light guide plate, and the emergent light rays can be homogenized by attaching the optical membrane on the surface of the non-pattern light guide plate on the premise of not changing the structure of the existing non-pattern light guide plate.
Fig. 1 is a schematic structural diagram of an optical film for a light guide plate according to an embodiment of the present invention, wherein the optical film 1 is attached to a side surface of a non-pattern light guide plate 2 of a backlight module (not shown) of a liquid crystal display, for example, in an embodiment shown in fig. 1, the optical film 1 is bonded to the side surface of the non-pattern light guide plate 2 by an adhesive layer 3. Of course, it should be understood by those skilled in the art that the optical film 1 may be attached to the light exit surface of the unpatterned light guide plate 2 as shown in the figure, may be attached to the light entrance surface of the unpatterned light guide plate 2, or may be attached to both side surfaces (the light entrance surface and the light exit surface) of the unpatterned light guide plate 2.
The optical film 1 comprises a transparent substrate film 11, a plurality of prism columns 12 which are arranged in parallel and have isosceles trapezoid-shaped cross sections are formed on the substrate film 11, the LED light source 4 is arranged on at least one side edge of the unpatterned light guide plate 2, which is perpendicular to the length direction of the prism columns 12, wherein the distance between the adjacent prism columns 12 close to the LED light source 4 is larger than the distance between the adjacent prism columns 12 far away from the LED light source 4. Further, the isosceles trapezoid of the cross section of the prism columns 12 has a side length a adjacent to the upper bottom side of the base material film 11 and a side length b distant from the lower bottom side of the base material film 11, where a > b, that is, the top surface of the prism columns 12 on the side close to the unpatterned light guide plate 2 is small and the top surface on the side close to the base material film 11 is large.
In addition, for example, in one specific embodiment shown in fig. 1, the two side edges of the unpatterned light guide plate 2 perpendicular to the length direction of the prism columns 12 are provided with the LED light sources 4, and the density of the prism columns 12 is larger, that is, the distance between the adjacent prism columns 12 is larger, and the density of the prism columns 12 is smaller, that is, the distance between the adjacent prism columns 12 is smaller, the closer to the LED light sources 4 from the LED light sources 4 at the two sides, the more the intermediate direction is.
Of course, it should be understood by those skilled in the art that, according to actual needs, the LED light source 4 may be disposed only on one side of the unpatterned light guide plate 2 perpendicular to the length direction of the prism columns 12, in this case, the closer to the LED light source 4 from the LED light source 4 to the far end direction thereof, the greater the density of the prism columns 12, that is, the greater the spacing between adjacent prism columns 12, and the farther from the LED light source 4, the smaller the density of the prism columns 12, that is, the smaller the spacing between adjacent prism columns 12.
The optical film for the light guide plate with the structure of the invention provides a backlight which can make the brightness of the whole display uniform and eliminate the defect of non-uniform brightness of the liquid crystal display by attaching the optical film with the specific pattern structure of the invention on the surface of the light guide plate without changing the structure of the existing light guide plate without patterns.
further, as shown in fig. 2, it shows an enlarged cross-sectional view of the prism column according to an embodiment of the present invention, in this embodiment, the side length a of the isosceles trapezoid of the cross-section of the prism column 12 is less than 100 μm, the side length b is greater than 2 μm, and the included angle α between the waist of the isosceles trapezoid and the straight line perpendicular to the upper base line is 25 to 50 degrees, in this embodiment, the prism column 12 with the isosceles trapezoid cross-section is adopted because the prism column 12 needs to be attached to the unpatterned light guide plate 2, and the side contacting with the unpatterned light guide plate 2 needs to have a certain area to be stably combined with the unpatterned light guide plate 2, so the side length b is set to be at least greater than 2 μm.
The above embodiments of the present invention provide specific parameter relationships of isosceles trapezoids of the cross section of the prism columns 12, and there is no technical teaching in the prior art to obtain the above parameter relationships, and those skilled in the art can obtain better display effects according to the parameter relationships.
In order to further obtain better processing characteristics and display effects, in a preferred embodiment, the optical film 1 is bonded to the side of the unpatterned light guide plate 2 by an adhesive layer 3; the adhesive layer 3 is preferably made of a heat-curable or ultraviolet-curable polymer.
Also for further obtaining better processing characteristics and display effects, in a preferred embodiment the substrate film 11 is made of PET, PP or PC plastic; the prism columns 12 are made of a thermosetting or ultraviolet-curable polymer. In the present embodiment, the prism columns 12 may be formed on the base material film 11 by conventional thermocompression molding or ultraviolet light irradiation molding.
In order to prevent the optical film from being deformed by heat or moisture during bonding, in a preferred embodiment, the thermal expansion coefficient of the unpatterned light guide plate 2 is limited to be smaller than that of the prism columns 12, and the thermal expansion coefficient of the prism columns 12 is smaller than that of the adhesive layer 3, so as to obtain a more stable and firm bonding structure.
In addition, based on the above detailed description, the present invention can also provide a backlight module for a liquid crystal display having the above optical film, specifically, as shown in fig. 1, the backlight module of the present invention can include a non-pattern light guide plate 2 and an optical film 1 in any one or a combination of the above embodiments, wherein the optical film 1 is attached to a side surface of the non-pattern light guide plate 2 of the backlight module of the liquid crystal display.
It should be appreciated by those of skill in the art that while the present invention has been described in terms of several embodiments, not every embodiment includes only a single embodiment. The description is given for clearness of understanding only, and it is to be understood that all matters in the embodiments are to be interpreted as including technical equivalents which are related to the embodiments and which are combined with each other to illustrate the scope of the present invention.
The above description is only an exemplary embodiment of the present invention, and is not intended to limit the scope of the present invention. Any equivalent alterations, modifications and combinations can be made by those skilled in the art without departing from the spirit and principles of the invention.