JP2004077860A - 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 is 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, 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: Spacer elements 15a and 15b are provided at both the array substrate 19 and the counter substrate 20 so as to be opposed to each other, the tips of the spacer elements 15a and 15b opposed to each other are made to abut against each other to form the spacer 15 and stress is absorbed by sliding operation between the spacer elements 15a and 15b. <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 spacer element facing each substrate is formed, and the tips of the spacer elements are brought into contact with each other. And a liquid crystal display device serving as a spacer for defining an interval between the two substrates.
[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. 6, the active matrix type color liquid crystal display device has a thin film transistor using amorphous silicon as a semiconductor layer in a matrix on a substrate 61 made of a transparent glass material having a thickness of about 0.5 to 1 mm. (TFT) 62 is provided, and a plurality of coloring layers 63B, 63G, 63R forming three color filters 63 of blue, green and red made of acrylic material or the like are provided so as to cover at least a part of the TFT 62. . Through holes 64B, 64G, 64R are formed in the colored layers 63B, 63G, 63R, respectively, and a plurality of transparent pixel electrodes 65 connected to the TFT 62 are arranged on the color filter 63. And an array substrate 67 on which an alignment film 66 made of polyimide or the like is formed.
[0003]
A counter substrate 68 disposed opposite to the array substrate 67 similarly has a substrate 69 formed of a transparent glass material having a thickness of about 0.5 to 1 mm. A transparent opposing electrode 70 made of ITO or the like is provided on the opposing surface opposing the. On the counter electrode 70, an alignment film 71 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 67 to the opposing substrate 68, and the electrode transfer material causes a gap between the array substrate 67 and the opposing substrate 68. The connection is made electrically.
[0005]
The array substrate 67 and the opposing substrate 68 are opposed to each other with a predetermined gap defined by a plurality of spacers 72 interposed between the substrates 67 and 68, and the peripheral portion is a heat or ultraviolet curing type. A liquid crystal member 74 is sealed in the gap, and a frame layer 75 is formed on the surface of the substrate 61 or the like, if necessary, by sealing the liquid crystal member 74 with a sealing material 73 made of an acrylic or epoxy adhesive. The liquid crystal panel 76 is configured by being disposed on the upper side.
[0006]
A polarizing plate 77 is adhered to both outer surfaces of the liquid crystal panel 76 with an adhesive, and a backlight or a reflecting plate (not shown) is provided outside the polarizing plate 77 on the array substrate 67 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 62 is driven to control the switching of the pixel electrode 65 so that the pixel electrode 65 is supplied to the counter electrode 70 facing the voltage. A predetermined color image is displayed by controlling the liquid crystal member 74 on each pixel electrode 65 to perform the role of an optical shutter based on the 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 at all because a glass material having a thickness of about 0.5 to 1 mm is used for both substrates 61 and 69, and 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 61 and 69 have flexibility. Therefore, the glass substrate is formed into an ultrathin plate having a thickness of 0.1 mm or less, and this substrate is applied to the array substrate 67 and the counter substrate 68 of the liquid crystal display device so that the weight is reduced and the 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 67 and the counter substrate 68 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. 7, in the liquid crystal display device having flexibility, the array substrate 67 and the opposing substrate 68 are frequently bent and used inevitably. Therefore, both substrates 67 and 68 receive stress in opposite directions. For this reason, the spacer 72 interposed between the two substrates 67 and 68 to keep the distance therebetween is moved by the spherical spacer 72, so that at least one end is attached to one of the two substrates 61 and 69. It must be fixed and fixed in position. Even in this case, a phenomenon occurs in which the free end of the spacer 72 is forcibly pulled in the bending direction. One end of the spacer 72 is fixed to, for example, the array substrate 67 in order to position the spacer 72 so as to be set in the non-display area. In the direction, and is deformed as shown by the broken line in the figure. When the degree of curvature is weak, the spacer 72 is only deformed in accordance with the stress, but when the degree of curvature is further increased, the spacer 72 is formed on the counter substrate 68 without being able to withstand the stress. It can be dragged on the alignment film 71 surface. As a result, at the free end of the spacer 72, the alignment film 71 or even the counter electrode 70 together with the alignment film 71 may be damaged, or the spacer 72 itself may be broken, and a good liquid crystal display function may be exhibited. Not only will it not be possible, but once it is damaged or destroyed, it will not be possible to return to the current state, so it will appear on the screen as a defect in the displayed image or display unevenness, and the image quality will be greatly reduced. The product value itself.
[0012]
The present invention has been made in view of such a problem, and a spacer is constituted by a pair of spacer elements formed on both surfaces of an array substrate and a counter substrate, and both spacer elements are formed on a contact surface of the spacer element. An object of the present invention is to provide a liquid crystal display device with good display quality by preventing the spacer from damaging the alignment film and the like by being configured to slide.
[0013]
[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 defining a gap between the two, and a liquid crystal member sandwiched between the opposing array substrate and the opposing substrate, the spacer includes a pair of spacer elements formed on both the array substrate and the opposing substrate. In addition, the tips of the spacer elements are brought into contact with each other.
[0014]
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 spacer absorbs the stress fluctuation by sliding between the spacer elements. This makes it possible to prevent damage to the alignment film and the like due to the spacer and to prevent the spacer itself from being broken, and to obtain a liquid crystal display device with good display quality.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0016]
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.
[0017]
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.
[0018]
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.
[0019]
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. When patterning the color filter 13 material, the spacer element 15a formed by sequentially laminating the coloring layers 13R, 13G, and 13B constituting the color filter 13 is formed between the first and second color pixel patterns and the third color. 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 of the first color and the pixel patterns of the second color and the third color, respectively. The location where the spacer element 15a 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.
[0020]
In addition, a transparent pixel electrode 16 is formed on the color filter 13 by depositing ITO or the like to a thickness of 1500 ° by a sputtering method, and patterning by a photolithography method to form a transparent pixel electrode 16. It is connected to the source / drain passage of the TFT 12 via each through-hole portion 14R, 14B, 14G. These TFTs 12 are arranged at intersections of signal lines and scanning lines arranged in a matrix. Further, an alignment film 17 formed by applying polyimide or the like to a thickness of 600 mm is arranged on the pixel electrodes 16. Thus, an array substrate 19 is formed.
[0021]
On the other hand, a counter substrate 20 is arranged to face the array substrate 19. The opposing substrate 20 has a transparent opposing electrode 22 made of ITO or the like on the opposing surface of a substrate 21 made of a transparent glass material having an initial thickness of 0.7 mm, and a polyimide on the opposing electrode 22. An alignment film 23 having a thickness of 600 ° is sequentially stacked and formed on the alignment film 23. Further, a spacer element 15b is provided on the alignment film 23 at a position facing the spacer element 15a so that the tip thereof contacts the spacer element 15a. To form the counter substrate 20.
[0022]
The opposing substrate 20 and the array substrate 19 are, for example, heated while maintaining a predetermined gap by a spacer 15 composed of a pair of a spacer element 15a of a stacked type and a spacer element 15b having the ends abutting on the spacer element 15a. The periphery except for the injection port is fixed by heat bonding with a sealing material 25 made of a hardening type epoxy adhesive, and an electrode transfer material for applying a voltage from the array substrate 19 to the counter substrate 20 is used as a sealing material. It is formed on an electrode transfer electrode (not shown) around 25. In this state, the surfaces of the substrate 11 and the substrate 21 are mechanically polished or chemically polished or a combination of both, and the like, so that the thickness of each of the substrates 11 and 21 is 0.1 mm, and the substrates 11 and 21 have flexibility. Further, flexible reinforcing plates 18 and 24 made of a transparent resin plate or the like for preventing damage are attached to the outer surfaces of the substrates 11 and 21. A liquid crystal member 26 made of, for example, a fluorine-based liquid crystal compound is injected into the gap between the array substrate 19 and the counter substrate 20, and then the injection port is sealed with an ultraviolet curing resin to form a liquid crystal panel 27. .
[0023]
Further, a polarizing plate 28 is bonded and fixed to the outer surfaces of the reinforcing members 18 and 24 of the array substrate 19 and the counter substrate 20 of the liquid crystal panel 27, respectively. A backlight, a reflection plate (not shown), and the like are arranged accordingly, and a frame layer 29 is arranged around the color filter 13 to constitute a color liquid crystal display device.
[0024]
When the color liquid crystal display device is configured as described above, when the color liquid crystal display device is curved, as schematically shown in FIG. 2, the spacer elements 15a, 15a and The contact surfaces of the tips 15b slide as indicated by broken lines in the figure, absorb the stress caused by the curvature of the array substrate 19 and the counter substrate 20, and the spacer 15 becomes the alignment film 17, 23, etc. of the array substrate 19 or the counter substrate 20. Can be prevented, or the spacer 15 itself can be prevented from being damaged. As a result, damage to the alignment films 17, 23, the counter electrode 22, the pixel electrode 16, the spacer 15, and the like can be prevented. And good display quality can be maintained. At this time, the sliding operation can be performed smoothly by flattening the contact surfaces of the spacer elements 15a and 15b.
[0025]
When the frame layer 29 is formed on the opposing substrate 20 as shown in FIGS. 3 and 4, the spacer element 15b can be formed together using the frame layer 29 material.
[0026]
That is, a black light-shielding film that forms the frame layer 29 is formed by photolithography on the outer peripheral portion of the display region that is the outer peripheral portion of the counter substrate 22 so as to hide the non-display region. The spacer element 15b may be formed on the array substrate 19 at a position facing the spacer element 15a.
[0027]
If the spacer element 15b is formed using the same material as the material of the frame layer 29 constituting the frame layer 29 in this manner, the spacer element 15b can be formed simultaneously using the same material when the frame layer 29 is formed. And the number of steps can be reduced. The same can be said for the spacer element 15a configured as a stacked type using the colored layers 13B, 13G, and 13R.
[0028]
Further, as shown in FIG. 5, a concave portion 30 is formed on one spacer element, for example, a front end contact surface of the spacer element 15a, and a front end of the other spacer element 15b is formed as a pointed end 31 such as a quadrangular pyramid or a cone. If the pointed end 31 is formed so as to be engaged in the recess 30, the spacer elements 15a and 15b can be slid without changing the engagement position, and the array substrate 19 and the opposing substrate 20 are curved. Even if the movement occurs, the sliding movement is performed in the recess 30 around the pointed end 31, so that the sliding of the both can be made smoother. The same effect can be obtained even if the tip of the spacer element 15b is formed as a hemisphere or the like fitted into the recess 30.
[0029]
In the above description, the case where the color filter 13 is disposed on the array substrate 19 side is described. However, the color filter 13 may be provided on the opposing substrate 20. It goes without saying that the present invention can be applied to not only a black and white liquid crystal display device.
[0030]
【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 slides between the spacer elements, so that the stress is reduced. Fluctuations can be absorbed, and damage to the alignment film and the like due to the spacer and destruction of the spacer itself can be prevented, so that a liquid crystal display device with good display quality can be obtained.
[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 schematic explanatory diagram for explaining an operation of a spacer which also forms the liquid crystal display device.
FIG. 3 is a sectional view showing another configuration of the liquid crystal display device according to the present invention.
FIG. 4 is a schematic explanatory diagram for explaining an operation of a spacer which also forms the liquid crystal display device.
FIG. 5 is a cross-sectional view showing another configuration of the spacer that similarly configures the liquid crystal display device.
FIG. 6 is a cross-sectional view showing a conventional liquid crystal display device.
FIG. 7 is a schematic explanatory diagram for explaining an operation of a spacer similarly configuring the liquid crystal display device.
[Explanation of symbols]
13: color filters 13b, 13G, 13R: colored layer 15: spacers 15a, 15b: spacer element 16: pixel electrode 19: array substrate 20: counter substrate 22: counter electrode 26: liquid crystal member 29: frame layer 30: recess

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 liquid crystal display device according to claim 1, wherein the spacer includes a pair of spacer elements formed on both the array substrate and the counter substrate, and the spacer elements are configured such that tips of the spacer elements are in contact with each other. 2. A liquid crystal display device according to claim 1, wherein the tip of said spacer element is formed flat. 2. The liquid crystal display device according to claim 1, wherein one end of the spacer element is formed in a concave shape, and the other end is engaged with the concave portion. 2. The liquid crystal display device according to claim 1, wherein a color filter made of a colored layer is formed on one of the array substrate and the counter substrate, and one of the spacer elements is formed by the colored layer material. 2. The liquid crystal display device according to claim 1, wherein a frame layer is formed on one of the array substrate and the counter substrate, and one of the spacer elements is formed by the frame layer material. A color filter composed of a colored layer is formed on one of the array substrate and the counter substrate, and a frame layer is formed on the other, and each spacer element is formed by the frame layer material and the colored layer material. The liquid crystal display device according to claim 1.

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