US20030179341A1 - Cassette for liquid crystal panel inspection and method of inspecting liquid crystal panel - Google Patents

Abstract

A cassette facilitates the inspection of liquid crystal panels and prevents breakage of the liquid crystal panels. The cassette includes a frame, plates arranged substantially parallel at top and bottom portions of the frame, and slots secured to the plates so as to secure the liquid crystal panels arranged within the cassette.

Description

• This application claims the benefit of the Korean Application No. P2002-15963 filed on Mar. 25, 2002, which is hereby incorporated by reference for all purposes as if fully set forth herein.[0001]
BACKGROUND OF THE INVENTION
• 1. Field of the Invention[0002]
• The present invention relates to a cassette containing at least one liquid crystal panel, and more particularly, to a cassette facilitating the inspection of at least one liquid crystal panel and a method of inspecting at least one liquid crystal panel.[0003]
• 2. Disscussion of the Related Art[0004]
• Generally, recent developments in technology have increased the demand for various types of display devices. In response to this increased demand, numerous types of flat panel displays (e.g., liquid crystal displays (LCDs), plasma display panels (PDPs), electro-luminescent displays (ELDs), vacuum fluorescent displays (VFDs), FED(field emission display), etc.) have been developed.[0005]
• Owing to their large contrast ratio, low power consumption, and their ability to display gray levels and moving pictures, LCDs are ideal in for use in notebook personal computers, desk-top monitors, and televisions, and the like.[0006]
• LCDs are fabricated using a series of fabricating processes including a substrate fabricating process, a liquid crystal panel fabricating process, and a module fabricating process.[0007]
• The substrate fabricating process includes steps of forming an array of thin film transistors (TFTs) and pixel electrodes on a first substrate (i.e., a TFT substrate) and forming a black matrix, a color filter layer, etc., on a second substrate (i.e., a color filter substrate).[0008]
• The liquid crystal panel fabricating process includes a step of bonding the TFT substrate and the color filter substrate together such that they are spaced apart at a uniform distance by a cell gap. The liquid crystal panel fabricating process further includes a step of injecting liquid crystal material into the cell gap.[0009]
• The module fabricating process generally includes steps required to fabricate an operational LCD module after a signal processing circuit is fabricated.[0010]
• A typical liquid crystal panel fabricating process will now be described in greater detail.[0011]
• A first cassette (not shown), housing a first plurality of TFT substrates, and a second cassette (not shown), housing a second plurality of color filter substrates, are mounted into respective ports via loaders.[0012]
• A plurality of gate lines are formed at fixed intervals along a first direction and a plurality of data lines are formed along a second direction, perpendicular to the first direction, on the TFT substrate. Accordingly, a plurality of pixel regions may be formed in a matrix pattern at the crossing of each of the gate and data lines. A plurality of pixel electrodes and a plurality of thin film transistors (TFTs) are formed at the pixel regions. A black matrix layer, color filters, and a common electrode are sequentially formed on the color filter substrate.[0013]
• Next, each of the TFT and color filter substrates are unloaded from the first and second cassettes, respectively, using a robot arm programmed to select each of the TFT and color filter substrates one at a time.[0014]
• Referring to FIG. 1, after an alignment material has been coated on the unloaded TFT and color filter substrates, an alignment process ([0015]1S) is performed on the coated alignment material to uniformly align liquid crystal material that is to be injected into the cell gap.
• After the alignment process is completed, the TFT and color filter substrates are cleaned ([0016]2S), spacers are dispensed on the TFT substrate so as to ensure that the cell gap is uniform (3S), sealant is coated on an edge of the color filter substrate such that a liquid crystal injection inlet is formed (4S), and the TFT and color filter substrates are then bonded to each other (5S).
• The bonded TFT and color filter substrates are then cut and processed into a liquid crystal panel ([0017]6S).
• Subsequently, liquid crystal material is injected through the liquid crystal injection inlet into the cell gap of each of the liquid crystal panels and the liquid crystal injection inlet is then sealed ([0018]7S).
• Lastly, the liquid crystal panel is inspected to determine the presence of any electrical failures and to evaluate the thermal stability of the injected liquid crystal material ([0019]8S).
• The electrical failure inspection is performed by performing a lighting test on each of the liquid crystal panels using an A/P station. Inspection to evaluate the thermal stability of the injected liquid crystal material is performed by storing a plurality of liquid crystal panels in a substantially vertical position for a predetermined amount time at a constant, elevated temperature, (e.g., greater than room temperature).[0020]
• A cassette, facilitating the transport and storage of a plurality liquid crystal panels, is therefore required in inspecting a plurality of the liquid crystal panels. The cassette is not only used in transporting, storing, and inspecting the plurality of liquid crystal panels, but is also used during the substrate, liquid crystal panel, and module fabricating processes.[0021]
• FIG. 2 illustrates a perspective view of a cassette used in inspecting liquid crystal panels.[0022]
• Referring to FIG. 2, a cassette used in inspecting liquid crystal panels includes a pair of[0023]side plates17 having slots for supporting opposing edges of a plurality ofliquid crystal panels11, aframe13 for supporting theside plates17, andbars15 for adjusting a distance between theside plates17 in accordance with sizes of various theliquid crystal panels11.
• [0024]Slots19 are arranged vertically along theside plates17 for supporting theliquid crystal panels11 arranged within the cassette. Dimensions of theslots19 are maintained such that the area of theliquid crystal panels11 contacting theslots19 is minimized.
• When the[0025]liquid crystal panels11 are inserted into thecassette30 as illustrated in FIG. 2, however, the productivity of an inspection of liquid crystal material for thermal stability and failure is minimized, as will be described in greater detail below.
• FIG. 3 illustrates a diagram of a liquid crystal panel inspecting method and FIG. 4 illustrates a perspective view of a problem encountered during inspection when using cassettes such as those illustrated in FIG. 2.[0026]
• Referring to FIG. 3, a plurality of[0027]liquid crystal panels11 containing liquid crystal material that are to be inspected for thermal stability, are oriented substantially vertically within acassette30. Thecassette30 is then loaded into anoven10 via a manually guided vehicle (MGV)20.
• After being heated for a predetermined amount of time, the[0028]cassette30 is unloaded from theoven10. Upon inspection, the thermal stability of the liquid crystal material within each of theliquid crystal panels11 is evaluated. If it is determined that bubbles are present at an upper portion of theliquid crystal panels11, the thermal stability of the liquid crystal material is determined to be insufficient and the liquid crystal panel is considered a failure. When theliquid crystal panels11 are arranged within thecassette30 in substantially vertical orientation, performing the thermal stability inspection may be facilitated as bubbles are generally easier to detect in liquid crystal panels oriented substantially vertically compared to liquid crystal panels oriented substantially horizontally.
• The horizontal lengths of both the[0029]cassette30 and the oven opening10Aillustrated in FIGS. 2 and 3, respectively, are greater than their respective vertical lengths. Accordingly, and referring to FIG. 4,liquid crystal panels11 must be loaded vertically into cassettes such as those illustrated in FIG. 2 when thecassette30 is loaded into theoven10.
• The liquid crystal panel arrangement illustrated in FIG. 4, however, is disadvantageous for the following reasons.[0030]
• First, when the plurality of the[0031]liquid crystal panels11 are inserted into thecassette30 illustrated in FIG. 4, theliquid crystal panels11 have a tendency to contact bothside plates17 and associatedslots19. Accordingly, theliquid crystal panels11 provided in the arrangement described above may be scratched or broken when the cassette is loaded and unloaded into and out of theoven10.
• Second, when the plurality of[0032]liquid crystal panels11 are inserted into thecassette30, as illustrated in FIG. 4, they are generally inclined and thus remove space within thecassette30 that would otherwise be available for otherliquid crystal panels11. Accordingly, space within the cassette is inefficiently managed.
SUMMARY OF THE INVENTION
• Accordingly, the present invention is directed to a cassette facilitating the inspection of liquid crystal panels and a method of inspecting liquid crystal panels that substantially obviates one or more problems due to limitations and disadvantages of the related art.[0033]
• An advantage of the present invention provides a cassette used in inspecting liquid crystal panels and a method of inspecting liquid crystal panels.[0034]
• In one aspect of the present invention, liquid crystal panels to be inspected may be arranged within the cassette while minimizing the risk of being broken.[0035]
• Additional advantages and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. These and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.[0036]
• To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a cassette facilitating the inspection of liquid crystal panels may include a frame, substantially parallel plates arranged at top and bottom portions of the frame, and slots coupled to the plates so as to secure liquid crystal panels arranged within the cassette.[0037]
• In one aspect of the present invention, the frame may have a horizontal length greater than a vertical length.[0038]
• In another aspect of the present invention, the frame may have a horizontal length less than a vertical length.[0039]
• In yet another aspect of the present invention, the frame have a horizontal length substantially equal to a vertical length.[0040]
• In still another aspect of the present invention, a width of the slots corresponds with a thickness of liquid crystal panels.[0041]
• Further, in another aspect of the present invention, the slots may be formed such that they contact at least a portion of the edges of each of the liquid crystal panels.[0042]
• In yet another aspect of the present invention, a method of inspecting liquid crystal panels may include the steps of inserting a plurality of liquid crystal panels into a substantially vertically oriented cassette, wherein the plurality of liquid crystal panels are arranged such that they are substantially parallel to each other, arranging the cassette such that the liquid crystal panels are substantially vertically oriented, loading the cassette into an oven, and maintaining the oven at a constant temperature (e.g., about 60˜120° C.).[0043]
• In still another aspect of the present invention, the method may further include the steps of unloading the cassette from the oven and inspecting each of the liquid crystal panels while they are oriented substantially vertically to evaluate the thermal stability of the liquid crystal material.[0044]
• In a further aspect of the present invention, at least one cassette may be loaded into the oven.[0045]
• It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.[0046]
BRIEF DESCRIPTION OF THE DRAWINGS
• The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention.[0047]
• In the drawings:[0048]
• FIG. 1 illustrates a flowchart of a liquid crystal panel fabricating method;[0049]
• FIG. 2 illustrates a perspective view of a cassette used in inspecting liquid crystal panels;[0050]
• FIG. 3 illustrates a diagram of a liquid crystal panel inspecting method;[0051]
• FIG. 4 illustrates a perspective view of a problem encountered during inspection when using cassettes such as those illustrated in FIG. 2;[0052]
• FIG. 5 illustrates a perspective view of a cassette facilitating the inspection of liquid crystal panels according to an embodiment of the present invention; and[0053]
• FIG. 6 illustrates a perspective view of a cassette facilitating the inspection of liquid crystal panels according to another embodiment of the present invention.[0054]
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
• Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.[0055]
• FIG. 5 illustrates a perspective view of a cassette facilitating the inspection of liquid crystal panels according to an embodiment of the present invention.[0056]
• Referring to FIG. 5, a cassette facilitating the inspection of liquid crystal panels may, for example, include a[0057]frame103 for holding a plurality ofliquid crystal panels101,plates107 arranged substantially parallel to each other at top and bottom portions of theframe103, andslots109 coupled to the plates for securing at least oneliquid crystal panel101 arranged within the cassette in a substantially vertical orientation.
• The[0058]frame103 may be characterized as having ahorizontal length103alonger than avertical length103b.
• In one aspect of the present invention,[0059]slots109 may be formed such an area of theslots109 contacting the at least oneliquid crystal panel101 is minimized.
• A method of inspecting liquid crystals using the aforementioned cassette will now be explained in detail.[0060]
• After insertion of the plurality of[0061]liquid crystal panels101, the cassette may, for example, be substantially vertically oriented. As shown in FIG. 5A, a plurality of theliquid crystal panels101 may be arranged in the cassette such that they are substantially parallel with each other and substantially horizontally oriented.Plates107 may be arranged at right and left sides of theliquid crystal panels101 and theliquid crystal panels101 may be arranged within theslots109.
• As shown in FIG. 5B, the cassette, having a plurality of liquid crystal panels arranged therein, may then be oriented substantially horizontally and loaded into an[0062]oven10 using an MGV (manually guided vehicle). In one aspect of the present invention, the plurality ofliquid crystal panels101 may be inserted into theoven10 such that they are oriented substantially vertically.
• When the[0063]liquid crystal panels101 are inserted into the cassette,slots109 may support at least a portion of the edges of theliquid crystal panels101. Moreover, the width of each of theslots109 may correspond with a thickness of each of the liquid crystal panels. In one aspect of the present invention, each of theliquid crystal panels101 in theirrespective slots109 may be separated from each other.
• After being heated for a predetermined amount of time at a constant temperature (e.g., about 60˜120° C.), the cassette may be removed from the[0064]oven10. Upon performing an inspection, the thermal stability of the liquid crystal material within each of theliquid crystal panels101 may evaluated. If it is determined that bubbles are found at an upper portion of any of theliquid crystal panels101 inserted into the cassette, theliquid crystal panel101 is determined to be a failure.
• According to the principles of the present invention, the cassette facilitates the vertical insertion and inspection of liquid crystal panels heated in an oven.[0065]
• FIG. 6 illustrates a perspective view of a cassette facilitating the inspection of liquid crystal panels according to another embodiment of the present invention.[0066]
• Referring to FIG. 6, a cassette facilitating the inspection of liquid crystal panels may, for example, include a[0067]frame203 for holding a plurality ofliquid crystal panels101,plates207 arranged substantially parallel to each other at top and bottom portions of theframe203, andslots209 coupled to theplates207 for securing at least oneliquid crystal panel101 arranged within the cassette in a substantially vertical orientation.
• The[0068]frame203 may be characterized as having ahorizontal length203aless than, or substantially equal to, avertical length203b.
• In one aspect of the present invention, the cassette may be smaller in size than cassettes such as those illustrated in FIG. 2. The smaller size facilitates the transport and orientation of cassettes having liquid crystal panels arranged therein. Additionally, the cassette of the present embodiment may be loaded and unloaded into and out from an oven.[0069]
• As similarly described with respect to the embodiment mentioned above,[0070]liquid crystal panels101 may be horizontally arranged within the cassette illustrated in FIG. 6, when the cassette is oriented substantially vertically. Once loaded with at least oneliquid crystal panel101, the cassette may be loaded and unloaded into and out from the oven. In one aspect of the present invention, the cassette may be oriented substantially horizontally within the oven and during inspection such that the liquid crystal panels are oriented substantially vertically.
• According to the principles of the present invention, the cassette may facilitate the inspection and transport of liquid crystal panels.[0071]
• According to the principles of the present invention, at least one liquid crystal panel may be arranged within the cassette. Further, the at least one liquid crystal panel may be prevented from breaking even when the cassette of the present invention is transported.[0072]
• It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.[0073]

Claims (17)

What is claimed is:

1. A cassette for liquid crystal panel inspection, comprising:

a frame;

two plates arranged substantially parallel to each other at top and bottom portions of the frame; and

slots secured to the plates for securing at least one liquid crystal panel within the cassette.

2. The cassette for liquid crystal panel inspection ofclaim 1, wherein the frame includes a horizontal length and a vertical length, wherein the horizontal length is greater than the vertical length.

3. The cassette for liquid crystal panel inspection ofclaim 1, wherein the frame includes a horizontal length and a vertical length, wherein the horizontal length is less than the vertical length.

4. The cassette for liquid crystal panel inspection ofclaim 1, wherein the frame includes a horizontal length and a vertical length, wherein the horizontal length is substantially equal to the vertical length.

5. The cassette for liquid crystal panel inspection ofclaim 1, wherein a width of the slots corresponds to a thickness of the at least one liquid crystal panel.

6. The cassette for liquid crystal panel inspection ofclaim 1, wherein an area of the slots contacts at least a portion of an edge of the at least one liquid crystal panel.

7. A method of inspecting liquid crystal panels, comprising:

arranging at least one liquid crystal panel within a cassette, wherein the cassette is oriented substantially vertically;

arranging the cassette such that the at least one liquid crystal panel arranged within the cassette is oriented substantially vertically;

loading the cassette into an oven; and

heating the loaded cassette in the oven at a constant temperature.

8. The method ofclaim 7, wherein the constant temperature is about 60˜120° C.

9. The method ofclaim 7, further comprising:

unloading the cassette from the oven; and

determining whether failure within the liquid crystal panels exists while the at least one liquid crystal panel is oriented substantially vertically.

10. The method ofclaim 7, wherein at least one cassette is loaded into the oven.

11. A cassette, comprising:

a frame having a horizontal length and a vertical length;

two opposing plates coupled to the frame; and

slots secured to the plates for securing at least one liquid crystal panel with the cassette, wherein the at least one liquid crystal panel is oriented substantially perpendicular to the two opposing plates.

12. The cassette according toclaim 11, wherein the two opposing plates are arranged substantially parallel to each other.

13. The cassette according toclaim 11, wherein the horizontal length is greater than the vertical length.

14. The cassette according toclaim 11, wherein the horizontal length is substantially equal to the vertical length.

15. The cassette according toclaim 11, wherein the horizontal length is less than the vertical length.

16. The cassette according toclaim 11, wherein a width of the slots corresponds to a thickness of the at least one liquid crystal panel.

17. The cassette according toclaim 11, wherein an area of the slots contacts at least a portion of an edge of the at least one liquid crystal panel.

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