JP2004077861A - Liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display wherein damage of an alignment layer and breakage of a spacer are prevented by solving a conventional problem that since a use of a current liquid crystal display is restricted because of its style formed in a solid state, it has begun to make trial of a liquid crystal display having flexibility by adopting a thin type glass substrate to an array substrate and a counter substrate as the glass substrate is recently made thin, and in this case, if the substrate having flexibility is used, opposing force operates to both substrates by curvature of the substrates, spacers are dragged to a curvature direction and the alignment layer is damaged by the dragged spacers and spacers themselves are broken. <P>SOLUTION: One end of a columnar spacer element 15a which constitutes the spacer 15 disposed between an array substrate 20 and a counter substrate 21 is fixed to the array substrate 20, a sliding part 15b is provided on a tip free end side of the spacer element 15a and the sliding part 15b is made to abut against the surface of the counter substrate 21 to relax stress by sliding operation of the spacer 15 when flexural stress is generated between the both substrates 20 and 21. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a liquid crystal display device in which a liquid crystal member is sandwiched between a flexible array substrate and a counter substrate, and in particular, a tip of a columnar spacer element having one end fixed to one substrate side is brought into contact with the other substrate side. The present invention relates to a liquid crystal display device configured to define a distance between two substrates by a spacer provided with a sliding portion that is in contact with the liquid crystal display device.
[0002]
[Prior art]
As a current color liquid crystal display device, an active matrix type color liquid crystal display device is predominant because there is no crosstalk between adjacent pixels and a good display image can be realized. As shown in FIG. 5, this active matrix type color liquid crystal display device has a thin film transistor using amorphous silicon as a semiconductor layer on a substrate 51 made of a transparent glass material having a thickness of about 0.5 to 1 mm. (TFT) 52 is provided, and a plurality of colored layers 53B, 53G, 53R forming a three-color filter 53 of blue, green, and red made of an acrylic material or the like are provided so as to cover at least a part of the TFT 52. . Through holes 54B, 54G, and 54R are formed in the colored layers 53B, 53G, and 53R, respectively, and a plurality of transparent pixel electrodes 55 connected to the TFT 52 are arranged on the color filter 53. And an array substrate 57 on which an alignment film 56 made of polyimide or the like is formed.
[0003]
An opposing substrate 58 disposed opposite to the array substrate 57 has a substrate 59 similarly formed of a transparent glass material having a thickness of about 0.5 to 1 mm. A transparent opposing electrode 60 made of ITO or the like is provided on the opposing surface opposing the. On the counter electrode 60, an alignment film 61 made of polyimide or the like is provided.
[0004]
In addition, a silver paste (not shown) or the like is disposed around the screen as an electrode transfer material for applying a voltage from above the array substrate 57 to the counter substrate 58, and the electrode transfer material causes a gap between the array substrate 57 and the counter substrate 58. The connection is made electrically.
[0005]
The array substrate 57 and the opposing substrate 58 are opposed to each other with a predetermined gap defined by a plurality of spacers 62 interposed between the substrates 57 and 58, and the peripheral portion is a heat or ultraviolet curable type. A liquid crystal member 64 is sealed in this gap, and a frame layer 65 is formed on the surface of the substrate 51 or the like, if necessary, through a sealing material 63 made of an acrylic or epoxy adhesive. The liquid crystal panel 66 is arranged above.
[0006]
A polarizing plate 67 is attached to both outer surfaces of the liquid crystal panel 66 with an adhesive, and a backlight or a reflecting plate (not shown) is provided outside the polarizing plate 67 on the array substrate 57 side as necessary. ) Are arranged to constitute a color liquid crystal display device.
[0007]
In the color liquid crystal display device configured as described above, for example, the backlight serving as a light source is turned on, and the TFT 52 is driven to control the switching of the pixel electrode 55 to be supplied to the counter electrode 60 facing the voltage of the pixel electrode 55. A predetermined color image is displayed by controlling the liquid crystal member 64 on each pixel electrode 55 to perform the function of an optical shutter based on a potential difference from the applied voltage. This color liquid crystal display device can display a color image with sufficient display quality such as luminance and contrast even in this configuration.
[0008]
However, this color liquid crystal display device has no flexibility because both substrates 51 and 59 are made of a glass material having a thickness of about 0.5 to 1 mm, so that the color television is exclusively used. It is used as a solid-state display device such as a John receiver, a color terminal display, or a monitor screen of a mobile phone. In the solidified liquid crystal display device, an attempt to give flexibility to the liquid crystal display device itself has been promoted in order to specify an intended use.
[0009]
In order to realize flexibility in this liquid crystal display device, it is essential that both substrates 51 and 59 have flexibility. Therefore, the glass substrate is formed into an ultra-thin plate having a thickness of 0.1 mm or less, and is applied to the array substrate 57 and the counter substrate 58 of the liquid crystal display device so that the weight is reduced and the glass substrate is not broken even when bent. It can be configured as a flexible liquid crystal display device with improved strength, and in the future it may be possible to expand into new fields such as electronic books, electronic organizers, advertising media of various forms with different shapes, etc. is there.
[0010]
[Problems to be solved by the invention]
However, it has been found that even if such a flexible glass substrate is simply employed as the array substrate 57 and the counter substrate 58 of the liquid crystal display device, it cannot be configured as a liquid crystal display device having good image quality. did.
[0011]
That is, as shown in FIG. 6, in the liquid crystal display device having flexibility, the array substrate 57 and the opposing substrate 58 are frequently bent and used inevitably. Therefore, both substrates 57 and 58 receive stresses in opposite directions. For this reason, the spacer 62 interposed between the two substrates 57 and 58 to keep the distance therebetween is constant in the spherical spacer 62 every time a stress is applied, and the position of the spacer 62 is deviated, so that a cell gap is not generated. In order to improve the uniformity, a columnar spacer 62 is used, and at least one end of the spacer 62 is fixed to one of the array substrate 57 and the counter substrate 58 side and fixed. There is a need. For example, when both ends of the spacer 62 are fixed to both the array substrate 57 and the opposing substrate 58 as illustrated, the spacer 62 may be broken without being able to withstand the stress.
[0012]
In order to avoid such an accident, for example, it is conceivable to fix one end of the spacer 62 to the array substrate 57 and make the other end a free end to abut on the surface of the counter substrate 58. However, even in this case, as shown in FIG. 7, the free end of the spacer 62 is forcibly pulled in the bending direction of the counter substrate 58 with which the spacer 62 is in contact, and is shown by a solid line in the figure from a broken line state in the figure. As a result, a state occurs in which the substrate is forcibly dragged on the surface of the counter substrate 58 in the bending direction.
[0013]
On the free end side of the spacer 62, when the degree of the bending is weak, the spacer 62 is only deformed according to the stress, but when the degree of the bending is further increased, the spacer 62 resists the stress. The surface of the alignment film 61 formed on the counter substrate 58 can be dragged without being completely removed. As a result, at the free end of the spacer 62 abutting on the surface of the counter substrate 58, the alignment film 61, or even the counter electrode 60 together with the alignment film 61, may be damaged, or the spacer 62 itself may be destroyed. In addition to being unable to exhibit good liquid crystal display functions, once damaged or destroyed, it cannot be restored to the current state, so it appears on the screen as defects in display images or uneven display. Not only significantly lowers the image quality, but also negates the commercial value itself.
[0014]
The present invention has been made in view of such problems, and has one end of a columnar spacer element fixed to one substrate side and a sliding portion formed at the other free end side tip portion, and An object of the present invention is to provide a liquid crystal display device having good display quality by preventing the alignment film and the like from being damaged by the spacer and destruction of the spacer itself by bringing the sliding portion into contact with the other substrate surface.
[0015]
[Means for Solving the Problems]
The present invention relates to a flexible array substrate provided with pixel electrodes, a flexible opposing substrate disposed opposite to the array substrate and provided with opposing electrodes on an opposing surface, the opposing substrate and the array substrate In a liquid crystal display device including a spacer that defines a gap between the substrate and a liquid crystal member sandwiched between the opposing array substrate and the opposing substrate, one end of the spacer is fixed to one of the array substrate and the opposing substrate. It is composed of a columnar spacer element and a sliding portion that comes into contact with the other substrate at the tip of the spacer element.
[0016]
With this configuration, even when the liquid crystal display device is curved and a stress in the opposite direction is applied between the array substrate and the opposing substrate, the liquid crystal display device does not cover the surface of the substrate contacted by the sliding portion provided on the spacer element. By sliding the substrate, it is possible to alleviate the stress due to the curvature of the substrate, to prevent the alignment film and the like from being damaged by the spacer and to prevent the spacer itself from being broken, and to obtain a liquid crystal display device with good display quality. be able to.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0018]
In the color liquid crystal display device according to the present invention, as shown in FIG. 1, an electrode wiring and a TFT 12 are formed on a main surface of a substrate 11 made of a transparent glass material by making use of fine techniques such as film formation and patterning. Provided. The TFT 12 and the electrode wiring are configured as follows, for example.
[0019]
That is, a molybdenum-tungsten (MoW) film is deposited on the main surface of the substrate 11 having an initial plate thickness of 0.7 mm by using a sputtering method and then patterned to form a gate electrode constituting the TFT 12 and a scanning signal. The scanning lines to be supplied are arranged. A gate insulating film made of silicon oxide or silicon nitride is provided on the substrate 11 so as to cover the gate electrodes and the scanning lines, and the surface of the gate insulating film on which the gate electrodes are arranged is formed by CVD. After depositing an amorphous silicon film, patterning is performed, and a semiconductor layer forming the TFT 12 is disposed. Further, molybdenum (Mo) / aluminum (Al) / molybdenum (Mo) is sequentially deposited and patterned on this semiconductor layer, so that a source electrode, a drain electrode and a video signal constituting the TFT 12 having a three-layer structure are formed. It is configured to form a signal line to be supplied.
[0020]
Around the TFT 12, RGB colored layers 13R, 13G, and 13B serving as color filters 13 that are color-coded into red (R), blue (B), and green (G) so as to cover at least a part thereof. A stripe is provided for each color. For example, when the first color is formed of red, the colored layers 13R, 13G, and 13B are formed by uniformly coating the entire surface of the substrate 11 with a UV-curable acrylic resin resist in which a red pigment is dispersed by using a spinner. Then, the substrate is exposed to ultraviolet light having a wavelength of 365 nm and an intensity of 100 mJ / cm ² through a photomask pattern that irradiates light to a portion to be colored red. The photomask pattern includes a stripe-shaped pattern portion corresponding to the first color, a square-shaped pattern portion of a through-hole portion for connection between a pixel electrode and a TFT 12, which will be described later, and a square shape for a stacked spacer element. And a pattern part having a shape.
[0021]
Thereafter, development is performed with a 1% aqueous solution of KOH for 20 seconds to form a 3.2 μm-thick red colored layer 13R and a through-hole portion 14R in the pattern portion. Subsequently, the green coloring layer 13G and the blue coloring layer 13B, and the respective through-hole portions 14G, 14B are formed in the same manner.
[0022]
Next, one end of a columnar spacer element 15a is fixed to the color filter 13 at a predetermined portion located in the non-display area of the color filter 13, and a plurality of spacers 15 provided with a sliding portion 15b at the free end of the other end. Is arranged. The position where the spacer 15 is located is provided between pixel patterns other than the display area of the pixel cell at least one per one or a plurality of pixel cells.
[0023]
Further, a frame layer 16 made of a black light-shielding film is provided by a photolithography method on an outer peripheral portion of a display region which is an outer peripheral portion of the color filter 13.
[0024]
Furthermore, a transparent pixel electrode 17 is formed on the color filter 13 by depositing ITO or the like to a thickness of 1500 ° by a sputtering method and patterning the film by a photolithography method. It is connected to the source / drain passage of the TFT 12 via each through-hole portion 14R, 14B, 14G. The TFTs 12 are arranged at intersections of signal lines and scanning lines arranged in a matrix. On the pixel electrodes 17, an alignment film 18 formed by applying polyimide or the like to a thickness of 600 mm is arranged. To form an array substrate 20.
[0025]
On the other hand, a counter substrate 21 is arranged to face the array substrate 20. The opposing substrate 21 has a transparent opposing electrode 23 made of ITO or the like on the opposing surface of a substrate 22 also made of a transparent glass material having an initial thickness of 0.7 mm, and a polyimide on the opposing electrode 23. The counter substrate 21 is formed by sequentially arranging and arranging alignment films 24 each having a thickness of 600 ° and the like.
[0026]
The opposing substrate 21 and the array substrate 20 are heated by a sealing member 26 made of, for example, a thermosetting epoxy adhesive, except for an injection port, while maintaining a predetermined gap by the spacer 15 having the sliding portion 15b. An electrode transfer material for applying a voltage from the array substrate 20 to the counter substrate 21 is formed on an electrode transfer electrode (not shown) around the seal member 26. Then, in this state, the surfaces of the substrates 11 and 22 are mechanically polished or chemically polished, or a combination thereof, or the like, so that the thickness of each of the substrates 11 and 22 is 0.1 mm, and the substrates 11 and 22 are made flexible. Then, flexible reinforcing plates 19 and 25 made of a transparent resin plate or the like for preventing damage are attached to the outer surfaces of the substrates 11 and 22. Then, a liquid crystal member 27 made of, for example, a fluorine-based liquid crystal compound is injected into a gap between the array substrate 20 and the counter substrate 21, and then the injection port is sealed with an ultraviolet curing resin to form a liquid crystal panel 28. .
[0027]
Further, a polarizing plate 29 is adhered and fixed to the outer surfaces of the reinforcing members 19 and 25 of the array substrate 20 and the counter substrate 21 of the liquid crystal panel 28, respectively. A color liquid crystal display device is configured by appropriately disposing a backlight, a reflection plate (not shown), and the like.
[0028]
When the color liquid crystal display device is configured as described above, when the color liquid crystal display device is curved, the side surface of the counter substrate 21 with which the sliding portion 15b formed at the free end portion contact portion of the distal end of the spacer element 15a contacts. The sliding portion 15 b slides on the surface of the counter substrate 21, thereby alleviating the stress caused by the curvature of the array substrate 20 and the counter substrate 21. A situation such as scratching the film 24 or the like or destruction of the spacer 15 itself can be prevented. As a result, it is possible to prevent the alignment film 24, the counter electrode 23, the spacer 15 and the like from being damaged. The display quality can be maintained.
[0029]
In addition, by setting the configuration on the counter substrate 21 side to include only the counter electrode 23 and the alignment film 24, the surface of the counter substrate 23 with which the sliding portion 15b contacts is flat, so that the sliding operation of the sliding portion 15b is performed. Since the smoothing can be performed, the damage of the alignment film 24 and the damage of the spacer 15 can be more effectively prevented.
[0030]
As shown in FIG. 2, the spacer 15 is formed by applying a lubricating member that easily slides to a free end portion of a spacer element 15a having one end fixed to form a sliding portion 15b. As this lubricating member, it is possible to reduce the coefficient of kinetic friction by selecting a member which is sticky so that the member is not scattered by sliding, and which is excellent in sliding property with respect to the counter substrate 21 to be brought into contact. In addition, it is possible to freely select a member in consideration of the alignment film 24 and the liquid crystal member 27, which is excellent in versatility.
[0031]
In addition, as shown in FIG. 3, if the tip of the spacer element 15a is formed in a spherical shape and this spherical tip is used as the sliding portion 15b, the spacer element 15a can be formed simultaneously with the formation of the spacer element 15a. Further, in this case, when the frame layer 16 is formed on the array substrate 20, the spacer 15 can be formed together using the frame layer 16 material.
[0032]
That is, a black light-shielding film for forming the frame layer 16 is formed by photolithography on the outer peripheral portion of the display region, which is the outer peripheral portion of the array substrate 20, so as to hide the non-display region. Is used to form the spacers 15 at the positions on the array substrate 20 where the spacers 15 are to be formed. If the spacer 15 is formed using the same material as the material of the frame layer 16 constituting the frame layer 16 in this manner, the spacer 15 can be formed simultaneously using the same material when the frame layer 16 is formed. Thus, the number of steps can be reduced.
[0033]
Further, as shown in FIG. 4, it is also possible to form the spacers 15 by using the colored layers 13B, 13G, and 13R when forming the color filter 13. That is, when patterning the material of the color filter 13, the coloring layers 13R, 13G, and 13B constituting the color filter 13 are sequentially laminated to form the spacer element 15a, and the spacer element 15a is used for the first and second colors. The color layers 13R, 13G, and 13B are formed at the same time as the color layers 13R, 13G, and 13B so as to be arranged between the pixel patterns, between the third color and the first color pixel pattern, and between the second color and the third color pixel pattern.
[0034]
At this time, of the colored layers 13B, 13G, and 13R forming the spacer element 15a, the colored layer having the lowest pigment concentration is laminated and located on the uppermost layer, and the uppermost colored layer functions as the sliding portion 15b. The configuration is as follows. Now, the pigment concentrations of the colored layers 13B, 13G, and 13R of the respective colors are set to about 11% by weight in the colored layer 13R for red, to about 10% by weight for the colored layer 13B for blue, and to the colored layer 13G for green. Is arranged to be about 9% by weight, a green coloring layer 13G material having a pigment concentration of about 9% by weight is disposed on the uppermost layer, and the green coloring layer 13G is disposed. The uppermost layer portion made of a material is used as the sliding portion 15B.
[0035]
With such a configuration, the kinetic friction coefficient of each of the coloring layers 13B, 13G, and 13R is substantially determined by the pigment concentration. Therefore, when the pigment concentration is high, the surface becomes more rough and kinetic. Becomes larger. Therefore, by arranging a portion formed of the green colored layer 13G material having the lowest pigment concentration as the uppermost layer, the surface thereof can be formed smoothly and the dynamic friction coefficient can be reduced. As a result, the coefficient of dynamic friction between the sliding portion 15b of the spacer 15 in contact with the surface of the counter substrate 21 and the counter substrate 21 can be reduced, and the stress between the spacer 15 and the counter substrate 21 can be reduced. It is possible to prevent breakage of the alignment film 24 and breakage of the spacer 15 itself, and it is not necessary to prepare a new member to form the sliding portion 15b. Is possible only by selecting and using a small member, so that the material cost can be reduced, and the formation of the spacer 15 can be performed simultaneously with the formation of the colored layers 13B, 13G, and 13R. Reduction can be achieved.
[0036]
In this case, the case where the green coloring layer 13G is used as the sliding portion 15b has been described, but this can be changed according to the pigment concentration, and the pigment concentration for each color used can be changed. Of these, the colored layer having the lowest pigment concentration may be disposed on the uppermost layer to form the sliding portion 15b, and the present invention is not limited to this example.
[0037]
The present invention is not limited to those described in these embodiments, but can be applied or modified in various ways. For example, the present invention can be configured such that the color filter 13 is provided on the opposing substrate 21 or the frame layer 16 Can be formed on the counter substrate 21 side, and it is needless to say that the present invention can be applied not only to a color liquid crystal display device but also to a black and white liquid crystal display device.
[0038]
【The invention's effect】
As described above, according to the present invention, even when the liquid crystal display device is curved and a stress in the opposite direction is applied between the array substrate and the opposing substrate, the spacer faces the substrate surface contacted by the sliding portion. A liquid crystal display device with good display quality can be obtained because the stress can be alleviated by smoothly sliding on the upper side, and damage to the alignment film and the like by the spacer and destruction of the spacer itself can be prevented. Can be.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a liquid crystal display device according to the present invention.
FIG. 2 is a cross-sectional view showing a spacer constituting the liquid crystal display device.
FIG. 3 is a sectional view showing another example of the configuration of the spacer.
FIG. 4 is a cross-sectional view showing still another configuration example of the spacer.
FIG. 5 is a cross-sectional view showing a conventional liquid crystal display device.
FIG. 6 is an explanatory diagram for explaining a destruction state of a spacer due to bending stress of the liquid crystal display device.
FIG. 7 is an explanatory diagram for explaining a state in which a counter substrate is damaged by bending stress of the liquid crystal display device.
[Explanation of symbols]
13: color filters 13B, 13G, 13R: coloring layer 15: spacer 15a: spacer element 15b: sliding portion 17: pixel electrode 20: array substrate 21: counter substrate 23: counter electrode 27: liquid crystal member

Claims (6)

A flexible array substrate with pixel electrodes,
A flexible counter substrate that is disposed to face the array substrate and includes a counter electrode on a counter surface;
A spacer defining a gap between the counter substrate and the array substrate;
In a liquid crystal display device comprising the opposed array substrate and a liquid crystal member sandwiched between the opposed substrates,
The spacer is composed of a columnar spacer element having one end fixed to one of the array substrate and the counter substrate, and a sliding portion that comes into contact with the other substrate at the tip of the spacer element. Liquid crystal display device. 2. The liquid crystal display device according to claim 1, wherein a lubricating layer is provided at a tip end of the spacer element of the spacer to form a sliding portion. 2. The liquid crystal display device according to claim 1, wherein the sliding portion is formed by making the tip of the spacer element of the spacer spherical. A color filter composed of a colored layer is formed on one of the array substrate and the counter substrate, a spacer element is formed by sequentially laminating the colored layer materials, and a colored layer having a minimum dynamic friction coefficient is arranged on the uppermost layer. The liquid crystal display device according to claim 1, wherein the sliding portion is formed by a sliding member. A color filter composed of a colored layer is formed on one of the array substrate and the counter substrate, a spacer element is formed by sequentially laminating the colored layer materials, and a colored layer having a minimum dynamic friction coefficient is arranged on the uppermost layer. 2. A liquid crystal display device according to claim 1, wherein a sliding portion is formed by a sliding member, and a counter electrode is arranged on a surface of the counter substrate contacting the sliding layer. 2. The liquid crystal display device according to claim 1, wherein a frame layer made of a black light-shielding film is formed on one of the array substrate and the counter substrate, and a spacer element is formed by the frame layer material.

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