JP3297385B2 - Liquid crystal display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device capable of absorbing bending deformation and plane distortion caused by a difference in heat resistance between an array substrate and a counter substrate.

[0002]

2. Description of the Related Art In general, a flat-type liquid crystal display device in which a light modulation layer is sandwiched between a liquid crystal material and an FL material in a space formed by two plane substrates called an array substrate and a counter substrate has an upper and lower plane. The display is performed by generating an electric field from the electrodes formed on each of the substrates to emit light or by partially changing the optical characteristics by the electric field. Usually, in this liquid crystal display device, in order to ensure transparency with respect to visible light, these array substrates and counter substrates are formed by using a material such as glass or plastic. The electrodes formed on one substrate are a plurality of partial electrodes, each of which is electrically insulated (hereinafter, referred to as a pixel portion or a pixel electrode as necessary)
So that a voltage can be selectively applied to each pixel portion.
It has a switching element such as Thin Film Transistor-).

In recent years, thin film transistors using amorphous silicon (amorphous silicon, hereinafter abbreviated as a-Si as necessary) or polycrystalline silicon (polysilicon, hereinafter abbreviated as p-Si as necessary) An active matrix type liquid crystal display device using as a switching element has attracted attention. The reason is that, by forming a TFT array using an a-Si film that can be formed at a low temperature using an inexpensive amorphous glass substrate, a large area, high definition and high image quality can be displayed. This is because there is a possibility that a reflective panel display (flat television) whose production cost is low can be realized.

When this type of display device is used in a portable device, the weight can be reduced by using plastic for the substrate. However, some of the processes for manufacturing the liquid crystal display device are performed at a high temperature, so that there is a problem that the substrate is likely to be thermally deformed. However, in particular, in an active matrix type LCD (Liquid Crystal Display), it is necessary to form a pattern with high alignment accuracy, so that a plastic substrate having a large thermal expansion coefficient cannot be used. On the other hand, in the counter substrate, only a process of forming a transparent pixel electrode and an alignment layer is required,
The necessity of making the counter substrate heat-resistant was reduced. However, when different materials are used for the active matrix array substrate and the opposing substrate, a difference occurs between the lengths of the two substrates due to different thermal expansion coefficients of the respective materials.
There is a problem that the display quality is impaired because the gap between the liquid crystals becomes non-uniform.

In the case of manufacturing this type of liquid crystal display device, a TFT array substrate and an opposing substrate for a cell are formed of a substrate such as glass, and liquid crystal is sealed between the TFT array substrate and a connection terminal of the liquid crystal cell. After connecting the PC board with the flexible substrate, mounting components such as a liquid crystal cell driving element, a power supply element, and a video memory are formed on the PC board. When such a liquid crystal display element is used for portable equipment, it is preferable that the liquid crystal display element be lightweight.
It is preferable to reduce the number of components such as the C board. In addition, a connection area is required to connect to the flexible substrate, which has determined the size of the frame outside the screen. In addition, since connection is required, a connection failure occurs at this location, which may cause a problem in reliability.

In such a display device, in particular, as the display screen becomes larger, there is a demand for reducing the storage space by, for example, folding the screen when the display device is not used. Also, there has been a demand that the display be performed with the screen appropriately bent even during the display operation. For this purpose, for example, as shown in FIG. 14 (a), there has been proposed a device in which a surface of a substrate 1 is covered with a flexible sheet 2 and a pixel portion (not shown) is formed thereon. A switching element (not shown) such as a thin film transistor capable of selectively applying a voltage to these pixel portions is formed in a pixel portion formed on the flexible substrate 2.
In addition, a circuit (not shown) such as wiring is formed, and finally a plurality of parallel cuts 3 reaching the flexible sheet 2 from the back surface of the substrate 1 are formed. Thus, the substrate 1 can be bent right and left.

Here, if the cut is formed at right angles to the surface as shown in FIG. 14A, both ends can be bent upward as shown in FIG. 14C.
If the cuts 3 are formed in a wedge shape so that the width gradually increases as the distance from the flexible sheet 2 increases as shown in FIG. 14B, both ends are bent upward as shown in FIG. 14C. Figure 1
As shown in FIG. 4 (d), both ends can be bent considerably downward. If such cuts 3 are formed not only in the front-rear direction in the figure but also in the left-right direction so as to be perpendicular to this, the substrate 1 can cope with bending deformation in all directions by the cuts in two orthogonal directions. Can be.

[0008] Further, as shown in FIG.
A hard substrate 4 made of glass or plastic;
An elastic part 5 formed of an elastic body on a part of the hard substrate 4
And a circuit such as a pixel unit, a switching element, and a wiring (not shown) are formed thereon. With such a configuration, as shown in FIGS. 15 (b) and 15 (c), the substrate 1 is bent in both V-shaped and inverted V-shaped directions at a portion of the elastic portion 5 made of an elastic body. Becomes possible.

As described above, in a conventional display device, a liquid crystal material or an EL material is sandwiched between two substantially parallel substrates, and an electric field is applied to these materials from electrodes formed on the upper and lower substrates. The display is performed by applying the voltage, but in order to maintain the uniformity of the display screen, the space between the two substrates must be kept uniform during the display. Also, even when the display device is not used,
Deformation that impairs the uniformity of the substrate spacing must be avoided. For this purpose, a spacer having a uniform particle size is used to secure an interval, and two parallel substrates are not independently deformed, and the other substrate follows the deformation of one substrate. It needs to be transformed.

[0010]

As described above, in the conventional liquid crystal display device, the array substrate on which the switching element layers and the cells of the pixel electrodes are formed and the flexible substrate on which the mounting parts are mounted are separately provided. Because it was formed, not only the number of components increased but also the weight increased, and when joining the array substrate and the opposing substrate, there was a non-uniform part in the joining gap due to the difference in the coefficient of thermal expansion between the two substrates. And the like.

In order to solve the above problems, the present invention prevents the nonuniformity of the gap of the liquid crystal cell due to the difference in thermal expansion coefficient and the like even if different materials are used for the array substrate and the opposite substrate of the liquid crystal display device. It is an object of the present invention to provide a liquid crystal display device capable of preventing display unevenness and image quality deterioration. In addition, the space between the upper and lower substrates can be kept uniform by deforming the other substrate by following the deformation of one substrate with the counter substrate, thereby maintaining the uniformity of the display screen. It is an object of the present invention to provide a bendable liquid crystal display device.

Further, by integrally forming a cell and a mounted component on an array substrate, it is possible to suppress an increase in the number of components and weight and to provide a highly reliable liquid crystal display device with a reduced number of contacts. Also aim. It is still another object of the present invention to provide a liquid crystal display device which does not require a region for connecting a cell substrate and a flexible substrate, suppresses an increase in a region other than the display of the display, and can secure an effective display area. Further, the present invention provides a liquid crystal display device which can prevent the occurrence of non-uniform cell gaps by making the thermal expansion coefficients of the array substrate and the counter substrate of different materials uniform even when a high-temperature process which is an essential step in an active matrix liquid crystal display device is performed. The purpose is to:

[0013] Furthermore, there is a demand for reducing the storage space by folding the screen when the apparatus is not in use, which has been caused by the enlargement of the display screen, and even when the screen is being folded even during the display operation. A plastic substrate that satisfies the demand for proper display and realizes a plastic substrate that can be easily deformed by weighing, has no cracks in the substrate when bent, and has a high heat-resistant temperature in response to processes such as annealing. It is another object of the present invention to provide a liquid crystal display device which can easily fold and store a plastic substrate having a high hardness and a low elastic modulus even when using the same.

[0014]

According to a first aspect of the present invention, there is provided a liquid crystal display device comprising: an array substrate on which a switching element for controlling a driving voltage and pixel electrodes are arranged in an array; A counter substrate provided with
A liquid crystal layer sandwiched between an array substrate and a counter substrate, wherein the counter substrate is formed of a hard material having a low coefficient of thermal expansion into a non-planar predetermined shape;
A soft portion integrally formed of a soft material having a high thermal expansion coefficient on at least one surface side of the hard portion as a core,
It is characterized by having.

According to a second aspect of the present invention, there is provided the liquid crystal display device according to the first aspect, wherein a mounting component including a mounting wiring and a driving circuit is provided around the area of the switching elements arranged in an array. The liquid crystal display device according to claim 1, further comprising an array substrate formed integrally and formed so that a region around the switching element can be folded back. In the above, the mounting wiring is formed around the area of the switching elements arranged in the array, and the area around the switching element is joined to the folded substrate formed so as to be able to be folded, and to the folded portion of the folded board. And a mounting board on which a mounting component including a drive circuit to which the mounting wiring is connected is provided. It is characterized in that.

According to a fourth aspect of the present invention, there is provided a liquid crystal display device according to any one of the first to third aspects.
The array substrate includes a hard portion formed of a hard material having a low thermal expansion coefficient in a predetermined shape, and a soft portion integrally formed of a soft material having a high thermal expansion coefficient on at least one surface of the hard portion as a core. It is characterized by:

According to a fifth aspect of the present invention, there is provided a liquid crystal display device comprising: an array substrate in which switching elements for controlling a driving voltage are arrayed; a counter substrate on which counter electrodes are provided; and a closed space between the two substrates. And a liquid crystal layer, wherein the array substrate is formed by forming a hard material having a low coefficient of thermal expansion in a planar shape on the liquid crystal layer side, and the hard portion is joined to the opposite side of the liquid crystal layer of the hard portion. A hard portion and a soft portion formed with a plurality of cuts extending from the plane opposite to the hard portion to the hard portion, and the array substrate and the counter substrate are spacers having a uniform particle size dispersed between the substrates. It is characterized in that it is adhered via a.

According to the present invention, since the mounting substrate is integrally formed with the array substrate, the overall weight is reduced, the number of contacts is reduced, the reliability is increased, and the mounting substrate is bent just outside the screen. The frame part can be made smaller. In addition, it is possible to prevent the image quality from deteriorating due to non-uniform gap due to the difference in thermal expansion between the array substrate and the opposing substrate. Further, with the above configuration, it is possible to prevent the gap between the cells from becoming non-uniform due to the deformation of the opposing substrate in accordance with the stress with the array substrate, and to realize good image quality. Further, according to the present invention, since the counter substrate is deformed in accordance with the deformation of the array substrate, there is no difference in substrate length, so that deformation such as warpage of the substrate is eliminated, and a uniform cell gap can be maintained, and image quality can be maintained. Does not deteriorate.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a liquid crystal display device according to the present invention will be described below in detail with reference to the accompanying drawings. First, a liquid crystal display device according to a first embodiment will be described with reference to FIGS. In the liquid crystal display device according to the first embodiment, a TFT layer, a wiring layer, an electronic circuit, and the like are integrally formed on one surface of a substrate made of a heat-resistant synthetic resin and bent, and the counter electrode is made of a soft synthetic resin. It is formed by a composite with a hard synthetic resin.

In FIG. 1A, the liquid crystal display device according to the first embodiment has an array substrate 10 on which switching elements and liquid crystal cells (not shown) are formed, and one surface of the array substrate 10 (the upper surface in FIG. ), And a liquid crystal layer 7 formed by enclosing a liquid crystal material in a space sealed by the seal 6 and the substrates 10 and 30. I have. The array substrate 10 has a glass substrate 11 as a base material, and is bent to the back side outside the bending frame 12 which is slightly larger than the counter substrate 30, and is bent to be positioned on the back side. A mounting component 13 in which a driving circuit, a video signal processing circuit, and the like are configured by a large-scale integrated circuit (LSI) is provided in the portion.

The detailed structure of the array substrate 10 having the above-described schematic structure will be described with reference to FIG. An array of the switching elements 16 and the pixel electrodes 17 as shown in FIG. 2 is formed in the array formation region 15 of the array substrate 10 by the following steps. First,
On a Kapton 200 μm thick glass substrate 11, MoT
a, Ta, TaN, Ta / TaNx, Al, Al alloy,
A material such as Cu, MoW or the like was deposited in a thickness of 3000 angstroms, and etching was performed to form patterns of wirings 14 such as gate lines, auxiliary capacitance (Cs) lines, and address lines (not shown). The substrate is not limited to Kapton, but may be any heat-resistant plastic such as Vectra between liquid crystal poly, aramid, and PES. At the same time, an LSI for driving and video signal processing around the screen and wiring for the mounting element were formed at the same time. Next, plasma CVD (Chemical Vapou)
r Deposition (chemical vapor phase)
3000 angstroms of iOx, 500 of SiNx
Angstrom laminated, undoped amorphous silicon (a-Si) 500 Å, stopper S
iNx was sequentially deposited at 2000 angstrom, and finally, a stopper SiNx of the TFT portion was patterned along with the gate using backside exposure.

Next, after depositing 500 nm of "n + a-Si 531", the n + a-Si, aS
i was etched to form a-Si islands. Next, IT
A pixel electrode was formed by laminating O at 1000 angstroms. Next, the SiNx / Si of the contact portion
A contact hole was formed by etching Ox. A signal line was formed by sequentially sputtering Mo500 Å / Al (aluminum) 3500 Å / Mo500 Å or Mo2000 Å thereon. At the same time, an LSI for driving and video signal processing around the screen and a wiring 14 for a mounting component 13 such as a mounting element were simultaneously formed.
Next, SiNx was deposited to a thickness of 2000 Å to form a protective film. Next, the TFT array was completed by etching the SiNx of the pixel portion and the peripheral contact portion. As shown in FIG. 2, this TFT array includes a predetermined number of TFTs 16 and pixel electrodes (cells) 17 formed in the array area 15 in the vertical and horizontal directions.
And a signal line 18 formed in the vertical direction in the figure, a gate line 19 formed in the horizontal direction, a capacitor and the like.

In the case of a reflection type liquid crystal display device, an Al electrode is used for the pixel electrode 17, and in this case, an acrylic resin HR is used.
A protective film is formed on the substrate 11 by C3 μm, and a contact hole is formed in a source portion of the TFT. Aluminum (Al) is sputtered thereon to a thickness of 2000 angstroms to form a pixel electrode, which is connected to a TFT source. Next, a protective film of SiO ₂ is deposited on a plastic substrate as a counter electrode substrate to a thickness of 1000 Å, and a red, blue, green color filter and an acrylic organic protective film are formed thereon with a pigment. 1000 Å of ITO is deposited thereon to form a counter electrode.

On these two substrates, 5
Coat with 00 angstrom and orient by rubbing. After the spacers are scattered on these substrates, the periphery of the pixels is sealed with an adhesive to form a seal 12, into which liquid crystal is injected to form a TFT-LCD. Note that the spacer may be of an adhesive type instead of an applied type.

As shown in FIG. 1 (a), the counter substrate 30 has a hard portion 31 having a quadrangular pyramid made of acrylic or the like to facilitate deformation due to thermal expansion. A soft portion 32 in which the front and back surfaces are coated with polypropylene to form flat front and back surfaces. The irregularities of the hard portion 31 such as acrylic can be easily formed by extruding a quadrangular pyramid on an acrylic plate. FIG. 1A shows a cross section of the array substrate 10 and the counter substrate 30. For example, when a plastic having a larger thermal expansion coefficient than glass by heating is used as the hard portion 31 of the counter substrate 30, Since the plastic substrate expands due to heating and becomes longer than the glass substrate as the array substrate 10, the plastic substrate receives more compressive stress than the glass substrate when slightly plastically deformed.

In this case, the acrylic having a higher elastic expansion coefficient receives a stronger compressive stress, and the bending angle is further increased. The soft portion 32 formed of polypropylene having a large breaking elongation and a small tensile elastic modulus is compression-deformed, shortens the length of the plate as a whole, slightly increases the plate thickness, and finally deforms to match the glass. Therefore, the longitudinal stress can be absorbed. Thereby, since the cell gap can be kept uniform, there is no problem of coloring due to a change in optical rotation caused by a change in the cell gap. When the array substrate 10 is transparent, the same transparent substrate may be used as the counter substrate 30. The acrylic unevenness is not limited to a quadrangular pyramid, and may be formed by a curved surface. The curved surface may be convex inward or concave. Also in this case, deterioration of the image quality could be prevented by the same effect as described above.

Next, as shown in FIG. 1 (b), a mounting component 13 composed of an electronic circuit such as an LSI and a capacitor is mounted on an electrode pad formed in a peripheral portion of the screen. Circuit functions include video processing circuits, array drive circuits, image memories,
CPU, power supply circuit and the like. Solder may be formed on the pad portion and thermocompression-bonded or another method may be used. After that, it is bent along the bending line shown by the broken line in FIG. 1B, and the mounting substrate is stored under the screen as shown in the sectional view. At this time, in order to ensure the bending, a rectangular bent frame 12 of a hardened plastic or metal having a size slightly larger than the screen is formed at the upper or lower part of the mounting substrate and used as a guide at the time of bending, whereby the bending can be surely performed. . In the case of a transmissive type, the backlight can be accommodated in a display area substantially by installing the backlight inside the bent array substrate. As shown in FIG. 1B, the area of the array substrate 10 can be reduced by notching one or more sides. FIG.
FIG. 3A is an enlarged cross-sectional view of the liquid crystal display device according to the first embodiment shown in FIG. 1A, and FIG.
FIG. 2B shows the array configuration in FIG. 2 in the array formation region 15.

In the liquid crystal display device according to the first embodiment described above, the array substrate 10 forms an array of the switching elements 16 and the pixel electrodes 17 in the array region 15 of the single substrate 11, and forms an electron around the array. Components 13 and wiring 14
However, the present invention is not limited to this, and the array substrate 10 may be configured as in the liquid crystal display device according to the second embodiment shown in FIG. The wiring layer 14 is formed on the front end side of the substrate 11 to be bent from the bending frame 12, and the mounting component 1 is formed on the surface side of the wiring layer 14.
3 as well as the mounting component 1 facing the mounting component 13 on the front side also on the front end side of the folded inside of the substrate 11.
3 may be provided. At this time, as shown in FIG. 4 (a), a plurality of through holes 8 penetrating both the front and back surfaces are formed on the front end side of the substrate 11, and the wiring layer 14 on the front side is formed through these through holes 8 through the through holes 8. By providing connection wiring, electrical connection in the liquid crystal display device can be secured. FIG. 4B is a plan view in which the array substrate 11 is developed. The configuration other than the mounting components 13 that are located inside the substrate 11 when folded and the method of manufacturing the liquid crystal display device are the same as those in the first embodiment. Since it is substantially the same as that of such a liquid crystal display device, a duplicate description will be omitted.

Next, a liquid crystal display device according to a third embodiment of the present invention will be described with reference to FIG. In the liquid crystal display device according to the third embodiment, FIG.
As shown in FIG. 1, the array substrate 10 is composed of a substrate 11 and a mounting component substrate 20, an array and wiring are formed on the substrate 11, and mounting components 13 are formed on one surface side of the substrate 20. 20 may be joined. The second embodiment having such a configuration is particularly effective in a transmission type liquid crystal device in which the light source 9 is provided on the back surface of the array substrate 10, and a power supply line may be integrally formed as the wiring 14. The power supply line is preferably formed to be thick because low resistance is required. However, it is easier to form a wiring layer by providing a separate substrate 20 and forming the power supply line thicker.

In the liquid crystal display device according to the third embodiment shown in FIG. 5, the mounting component 13 is provided only on one surface (the upper surface in the drawing) of the separate substrate 20 constituting the array substrate 10. However, the present invention is not limited to this. For example, a configuration in which the liquid crystal display devices according to the second and third embodiments are combined as in the liquid crystal display device according to the fourth embodiment shown in FIG. 6 may be employed. . That is, as shown in FIG. 6A, the liquid crystal display device according to the fourth embodiment includes an array substrate 10 composed of a substrate 11 and a separate eaves board 20, and both surfaces of the separate substrate 20 A mounting component 13 is provided. Further, a through hole 8 penetrating the upper and lower surfaces of the separate substrate 20 is provided, and a light source 9 is provided at an opening of the separate substrate 20. FIG. 6B also shows the liquid crystal display device according to the fourth embodiment having such a configuration.
As shown in the developed plan view of FIG. 1, the array configuration of the switching elements 16, the pixel electrodes 17, the video signal lines 18, the scanning signal lines 19, etc., formed on the array formation surface 15, Is formed on one surface side of the substrate 11, and then the end side is turned back along the broken line, whereby the substrate 11 on one side of the array substrate 10 can be formed, thereby saving the substrate material and facilitating the formation. Of the present invention can be sufficiently achieved.

The present invention is not limited to the above-described first to fourth embodiments. The array substrate 10 is not limited to Kapton (polyimide), but may be a liquid crystal polymer such as Vectra or Aramid if it is a heat-resistant plastic. Of course, or a transparent resin such as PES, acrylic, or Arton may be used. Further, the TFT is not limited to a-Si but may be formed of p-Si, CdS, or CdSe. In addition, the structure of the transistor may be either below the gate or above the gate. The display mode may be a transmission type or a reflection type, and the display mode of the liquid crystal is not limited to TN, but may be a guest host or a ferroelectric liquid crystal.

Further, the liquid crystal display devices according to the first to fourth embodiments described above have described a novel structure only for the array substrate 10 of the array substrate 10 and the counter substrate 30. Without being limited to this, FIG.
Various aspects of the configuration of the opposing substrate 30 shown in (a) are conceivable as in the embodiments described below. First, the liquid crystal display device according to the fifth embodiment shown in FIG.
As shown in the plan view of (a), in the liquid crystal display device, a counter substrate 30 in which divided quadrangular pyramid-shaped ridge lines 33 of a hard substrate 31 are alternately formed on an array substrate 10 is joined. . The manufacturing process of the liquid crystal display device according to the fifth embodiment will be described with reference to FIG. MoTa, Ta, TaN, Ta on an array substrate 10 such as a glass substrate.
/ TaNx, Al, Al alloy, Cu, MoW, etc.
Etching is performed by depositing 0 angstrom to form a pattern of a gate line, a Cs line, and an address line (not shown). Next, 3000 angstroms of SiOx and 500 angstroms of SiNx are stacked as an insulating film by a plasma CVD method, and undoped a-Si is
00 angstrom and 2000 angstrom of stopper SiNx were deposited.

The stopper SiNx of the TFT portion 15 is patterned along with the gate by using backside exposure, and “n + aS
i ”is deposited for 500 Å and then the TFT portion 1
The n + a-Si and a-Si of No. 5 were etched to form a-Si islands. Next, a pixel electrode was formed by depositing 1000 Å of ITO. Next, a contact hole was formed by etching the SiNx / SiOx of the contact portion. On top of this, Mo500 Å / Al (aluminum) 3500 Å / Mo500 Å or Mo20
00 angstrom was sputtered to form a signal line. Next, a protective film was formed by stacking 2000 Å of SiNx. The SiNx of the pixel portion and the peripheral contact portion is etched to form the TFT array 15
Was completed.

When the pixel electrode is of a reflection type, an Al electrode is used. In this case, a protective film is formed on the substrate using the acrylic photosensitive resin HRC 3 μm, and a contact hole is formed in the source portion of the TFT. On this, Al was sputtered at 2,000 Å to form a pixel electrode, and a TFT was formed.
Connect to the source.

Next, a SiO 2 protective film of 1000 Å is deposited on a plastic substrate as the counter electrode substrate 30, and red, blue, and green color filters and an acrylic organic protective film are formed thereon by using a pigment. 1000 Å of ITO is deposited thereon to form a counter electrode. Polyimide is placed on these two substrates by 50
0 angstrom coat and orientation by rubbing. After the spacers are scattered on these substrates, the periphery of the pixels is sealed with an adhesive seal 6, and liquid crystal 7 is injected therein to form a TFT-LCD. The spacer may be of a type to be bonded.

As shown in FIG. 7, the plastic used for the opposing substrate is easily deformed by forming irregularities of a quadrangular pyramid by a hard portion 31 made of an acrylic resin or the like, as shown in FIG. Upper and lower surfaces of the hard portion 31 were coated with a soft portion 32 such as a polypropylene resin to flatten the surface. The irregularities of the hard portion 31 such as acrylic can be easily formed by extruding a quadrangular pyramid on an acrylic plate. FIG. 7 (b) shows a cross section of the substrate. For example, when a plastic having a larger coefficient of thermal expansion than glass expands and becomes longer due to heating, and the plastic is slightly plastically deformed, the plastic substrate compresses more than the glass substrate. Subject to stress. In this case, the acrylic having a higher elastic expansion coefficient receives a compressive stress, and the bending angle of the rigid portion 31 of the rigid plastic that has been bent in advance increases. Polypropylene having a large elongation at break and a small tensile modulus is compression-deformed, shortening the length of the plate as a whole, slightly increasing the plate thickness, and finally deforming according to the array substrate 10 such as glass. Longitudinal stress can be absorbed. This allows
Since the cell gap can be kept uniform, there was no problem of coloring due to a change in optical rotation due to a change in the cell gap.

In the liquid crystal display device according to the fifth embodiment, a region divided for each pixel or switching element is set only on the counter substrate 30, and the hard substrate 3 is provided for each region.
Although the first pyramid ridge line 33 is formed, the present invention is not limited to this. For example, as in the liquid crystal display device according to the sixth embodiment shown in FIG. The hard portion 41 may be constituted by a soft portion 42 made of a soft plastic coated on both upper and lower surfaces of the hard portion 41. In this case, as shown in the plan view of FIG. 8A, the ridge line 4 similar to the ridge line 33 of the counter substrate 30 is also provided on the hard portion 41 of the array substrate 40.
3 will be formed.

In the liquid crystal display device according to the sixth embodiment configured as described above, the tensile strength of the hard portion 41 made of rigid plastic is preferably 30% or more greater than the tensile strength of the soft portion 42 made of soft plastic. preferable. Still preferably, the breaking elongation of the soft plastic is 50% or more. The difference in the refractive index is 0.15 in order to suppress the change in the optical path of the display light to such an extent that it cannot be seen.
The following is preferred. The tensile strength of ARTON and polypropylene is 7.5E2 and 3.0E2kg, respectively.
/ Cm2. Refractive index is 1.51 and 1.50 respectively
It is.

It should be noted that the present invention is not limited to the liquid crystal display device according to the sixth embodiment, but includes a rigid plastic and a soft plastic in a multilayer structure to suppress the deformation due to the expansion of the substrate and maintain the cell thickness. Anything is fine. It can be applied to both reflection type and transmission type. It is particularly effective for an active matrix type, but can also be applied to a simple matrix. The opposite substrate may be dyed R, G, B to form a color filter, and the black matrix may be formed by dyeing the substrate in a black furnace. TFT is a-Si
The present invention is not limited to this, and may be formed of p-Si, CdS, or CdSe. The display mode may be a transmission type, and the display mode of the liquid crystal is not limited to TN, but may be a guest host or a ferroelectric liquid crystal.
The LCD substrate is not limited to acrylic and polypropylene, and other plastic combinations may be used. The strength ratio between the rigid plastic and the soft plastic is preferably 1.3 times or more for the rigid plastic, and the difference in refractive index is preferably 0.15 or less, since the reflection and scattering of light are small. As the rigid plastic, acrylic, PES, or soft plastic may be a combination of polyethylene, PSF, and polybutylene. In addition, as the rigid plastic, Arton and the soft plastic may be a combination of polyethylene. Also, bent glass may be used instead of rigid plastic.

In each of the above-described embodiments, the hard portion 3 of the counter substrate 30 and / or the array substrate 40 is used.
1, 41 are formed in a bent shape, and the soft portions 3
However, the present invention is not limited to this, and the hard portion 3 made of a rigid plastic is used as in the liquid crystal display device according to the seventh embodiment shown in FIG.
It is also possible to form the wedge shape on one surface side of the first and first members 41, and to provide the soft parts 32 and 42 made of soft plastic so as to be bonded to the one side. In this case, the members of the counter substrate 30 and the array substrate 40 on the side where the liquid crystal layer 7 is injected are the hard portions 31 and 41, respectively.

A method for manufacturing the liquid crystal display device according to the seventh embodiment shown in FIG. 9 will be described. Wedge-shaped hard portions 31 and 41 are made of rigid plastic having high tensile strength and high tensile elasticity such as Arton manufactured by Nippon Gosei.
A soft plastic having a small tensile strength such as polypropylene and a large breaking elongation is applied and pressed onto the wedge-shaped surface to form the soft portions 32 and 42 having flat surfaces on the other surfaces. This makes it possible to form a substrate that is strong and can be bent and deformed. In the case of the array substrate 40, a TFT array is formed on the flat surface side of the hard portion 41. The strength is maintained to such an extent as to endure the process of forming the TFT by the rigid substrate, and the flexibility to deform by nearly 180 degrees can be realized. Next, a color filter, a counter electrode, and the like are formed on the counter substrate 30 having the same laminated structure. A spacer is arranged between the two substrates. An ultraviolet curable adhesive, a thermosetting resin, an epoxy adhesive, or the like is applied to the surface of the spacer, and is placed. After sealing, the adhesive is cured by ultraviolet irradiation, heat treatment, or the like.

Next, liquid crystal is injected to manufacture a liquid crystal display device. The wedge may be formed two-dimensionally as in the seventh embodiment shown in FIG. 9, or may be formed one-dimensionally as in the liquid crystal display device according to the eighth embodiment shown in FIG. . As shown in FIG. 10A, the one-dimensional wedge has a ridge line 33 or 43 that is linear in one direction when viewed two-dimensionally.

In addition, the unevenness of the hard portion 31 such as acryl of the counter substrate in the present invention is not limited to a quadrangular pyramid or a straight chevron, but may be a liquid crystal display according to a ninth embodiment shown in FIG. Like a device, it may be formed in a curved shape. In FIG. 11, a counter substrate 30 joined to a glass substrate 11 via a liquid crystal layer 7 sealed by a seal 6 has a hard portion 31 having a folded surface shape and upper and lower portions of the folded surface of the hard portion 31. And a soft portion 32 that is bonded to both surfaces and has both upper and lower surfaces formed on a plane. As described above, the hard portion 31 and the soft portion 3
Even if the bonding surface of No. 2 is a folded surface, deterioration of image quality can be prevented by the same effect as that of the above-described counter substrate having the pyramidal or chevron-shaped uneven surface in response to thermal changes in the manufacturing process. did it. Note that the line in the plan view shown in FIG. 11 indicates a ridge line at which the curvature of the folded surface is maximum.

Further, the present invention is not limited to the configuration in which the opposed substrate 30 has the fold-shaped hard portion 31 shown in the ninth embodiment, and the periphery of the opposed substrate 30 as in the tenth embodiment shown in FIG. A curved surface portion 35 for absorbing thermal expansion may be provided in the portion, and a flat surface 36 may be formed near the center of the counter substrate 30. In the tenth embodiment, the screen portion of the hard plastic of the counter substrate 30 is a flat surface 36, and the curved portion 35 is formed on the peripheral portion near the seal 6, so that the curved portion 35 thermally deforms. Will be absorbed. Also, T
As the FT array substrate 10, instead of glass, polyimide, Kepler, or Vectra having good heat resistance and chemical resistance may be used. Since these heat-resistant plastics have better heat resistance than glass, the weight of the LCD can be reduced.

It should be noted that the present invention is not limited to the above-described embodiments, but can be applied to any of the reflection type and the transmission type. Especially effective for active matrix type,
It is also applicable to simple matrices. The counter substrate is R,
The color filter may be formed by dyeing G and B, and the black matrix may be formed by dyeing the substrate black. Further, the TFT is not limited to a TFT formed of a-Si, but may be formed of p-Si, CdS, or CdSe. The display mode may be a transmission type or a reflection type, and the display mode of the liquid crystal is not limited to TN, but may be a guest host or a ferroelectric liquid crystal. The LCD substrate is not limited to acrylic and polypropylene, and other plastic combinations may be used. The strength ratio of the rigid plastic to the soft plastic is preferably 1.3 times or more, and the rigid plastic is preferably large, and the difference in refractive index is preferably 0.15 or less because light reflection and scattering are small. Acrylic, PE as rigid plastic
S and the soft plastic may be a combination of polyethylene, PSF and polybutylene.

Finally, a liquid crystal display according to an eleventh embodiment of the present invention will be described with reference to FIG. The liquid crystal display device according to the eleventh embodiment has the structure shown in FIG.
And an array substrate 50 having a soft portion 52 made of a flexible acrylic sheet or the like and a hard portion 51 made of an acrylic substrate or the like bonded to the soft portion 52, and a seal (not shown) And a counter substrate 30 such as a flexible sheet that sandwiches the liquid crystal layer 7 sealed by the liquid crystal layer 7. Cut portions 53 are formed at a predetermined pitch in the hard portion 51 of the array substrate 50, and the cut portions 53 allow the array substrate 50 to change in shape due to thermal expansion together with the counter substrate 30 made of a flexible sheet and the soft portion 52. It has become available.

The structure of the TFT is not limited to the etching stopper type as in the above-described embodiments, but may be a channel etching type TFT structure, and the gate is not limited to that provided below. It may be of an overlying structure. Further, the organic insulating film on the TFT is not limited to the one formed of an acrylic resin, but may be BCB.
The insulating film may be photosensitive or non-photosensitive. Furthermore, the substrate is not limited to a combination of different resins, and may be a combination of a non-organic material such as glass or ceramic and a resin.

The manufacturing process of the liquid crystal display device according to the eleventh embodiment will be described with reference to FIGS. First, as a starting substrate, for example, an acrylic substrate 51 on the surface of which a flexible acrylic sheet 52 is adhered using an adhesive is prepared, and a pixel portion (not shown) is selectively formed thereon, and the pixel portion is selectively formed. A switching element (not shown) such as a thin film transistor for applying a voltage, a wiring circuit (not shown), and the like are formed to form an array substrate 50 as a lower substrate.
(A)｝. Next, after dispersing spacers 55 with an appropriate uniform particle size over the entire surface of the array substrate 50, the array substrate 50 is covered with a counter substrate (upper substrate) 30 made of a flexible sheet made of an elastic material such as polypropylene. The array (lower) substrate 50 is opposed to (upper substrate) 3 by a thermosetting resin or the like previously applied on the spacer 55.
0 (FIG. 13B). Next, from the back surface of the array (lower) substrate 50, the soft portion 52 of the acrylic sheet
Is formed to complete the liquid crystal display device (FIG. 13C).

Thus, as shown in FIG. 13C, in the liquid crystal display device according to the eleventh embodiment, the hard portions 51 divided by the cut portions 53 are connected by the soft portions 52 made of a flexible sheet. The opposing (upper) substrate 30 made of an elastic material is bonded to the array substrate 50 as a lower substrate via a spacer 55 having a uniform particle size. For this reason,
In the liquid crystal display device according to the eleventh embodiment, even when the vicinity of the center is bent downward as shown in FIG. 14C, the vicinity of the peripheral portion is bent downward as shown in FIG. 14D. Even in this case, the upper opposing substrate 30 expands and deforms following the movement of the lower array substrate 50 due to its elasticity, and is sandwiched between the upper and lower substrates by the spacer 55 having a uniform particle size. The thickness of the liquid crystal layer can be kept constant, and the uniformity of the display screen can be ensured.

In the eleventh embodiment, a member made of a homogeneous material is used as a substrate material and a flexible sheet connecting them. For example, a glass substrate is used as the substrate material, and a flexible acrylic material is used. For example, members made of different materials may be combined, such as connecting with a sheet. However, when a member made of a different material is used, the difference in the refractive index due to the material at the interface increases, which may cause a reduction in light use efficiency or image distortion due to reflection. It is desirable to use a member made of the same material as the material of the flexible sheet connecting the two.

In order to apply an electric field to a liquid crystal material, an EL material and the like sandwiched between the upper and lower two sheets, an ITO or the like is used as an opposite electrode to the lower electrode on an upper substrate made of an elastic material. The upper electrode may be formed, and a potential difference may be applied between the upper electrode and the lower electrode. However, an electrode formed by being applied on a substrate having such elasticity often causes cracks, peeling off from the substrate, etc. when the substrate undergoes elastic deformation, thereby increasing the reliability of the device. May be impaired. In such a case, the upper substrate can be formed by using a polymer having conductivity itself, such as polyacetylene to which a small amount of a donor or acceptor component is added, or by using a laminated structure with polypropylene or the like.

In the eleventh embodiment, since the upper substrate made of a stretchable material is directly adhered to the lower substrate via the spacer, the liquid crystal display device has a structure as shown in FIG. When bent downward, the upper substrate 30 is deformed following the movement of the lower substrate 50, and uniformity of the display screen can be ensured. However, when bent upward, it cannot be handled. For this purpose, in the step of FIG. 13B, after the spacers 55 having a uniform particle size are sprayed, the upper substrate 30 is adhered to the lower substrate 50 in a state where the upper substrate 30 is stretched in a desired direction in advance. In the case where the vicinity of the center of the display device is bent upward as shown in FIG.
0 can be dealt with by causing a shrinkage deformation following the movement of the lower substrate 50.

Although the eleventh embodiment has been described using a substrate capable of causing bending deformation by providing a cut surface in the substrate as the lower substrate, the present invention is not limited to this. The method of the present invention can also be applied to a case where a substrate having a portion made of an elastic body in advance as a part of the substrate as shown in FIG. 15 is used as the lower substrate.

[0054]

As described above, in the liquid crystal display device of the present invention, even when the liquid crystal display device is subjected to deformation such as bending, the upper and lower substrates constituting the device are deformed following each other. In addition to being able to cause the deformation, the space formed between these two substrates upon deformation can be sensitized to be uniform, the thickness of the liquid crystal layer can be kept constant, and the uniformity of the display screen can be ensured. .

Further, according to the present invention, since the counter substrate is deformed in accordance with the deformation of the array substrate, there is no difference in substrate length between different materials. Since the cell gap can be maintained, the image quality is not degraded, and the light-weight plastic can be used for the counter substrate.
A CD can be realized.

Further, according to the present invention, since the mounting substrate is integrally formed with the array substrate, the overall weight is reduced, the number of contacts is reduced, the reliability is increased, and the mounting substrate is bent just outside the sleeping screen. The frame can be reduced. As a result, cost reduction can be realized, and thereby a lightweight and low-cost TFT-LCD can be realized. Further, it is possible to prevent the deterioration of the image quality due to the non-uniform gap due to the difference in the coefficient of thermal expansion of the substrate.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view showing a configuration of an array substrate and a counter substrate of a liquid crystal display device according to a first embodiment of the present invention, and FIG.

FIG. 2 is a circuit diagram illustrating mounting of an array substrate of the liquid crystal display device according to the first embodiment.

FIGS. 3A and 3B are a cross-sectional view and a developed plan view illustrating a configuration of the liquid crystal display device according to the first embodiment.

FIGS. 4A and 4B are a cross-sectional view and a developed plan view illustrating a configuration of a liquid crystal display device according to a second embodiment of the present invention.

5A is a cross-sectional view illustrating a configuration of a liquid crystal display device according to a third embodiment of the present invention, and FIG.

FIGS. 6A and 6B are a cross-sectional view and a developed plan view illustrating a configuration of a liquid crystal display device according to a fourth embodiment of the present invention.

FIGS. 7A and 7B are a plan view and a cross-sectional view illustrating a configuration of a liquid crystal display device according to a fifth embodiment of the present invention.

FIGS. 8A and 8B are a plan view and a cross-sectional view illustrating a configuration of a liquid crystal display device according to a sixth embodiment of the present invention.

FIGS. 9A and 9B are a plan view and a cross-sectional view illustrating a configuration of a liquid crystal display device according to a seventh embodiment of the present invention.

FIGS. 10A and 10B are a plan view and a cross-sectional view illustrating a configuration of a liquid crystal display device according to an eighth embodiment of the present invention.

FIG. 11 is a sectional view showing a configuration of a liquid crystal display device according to a ninth embodiment of the present invention.

FIG. 12 is a sectional view showing a configuration of a liquid crystal display device according to a tenth embodiment of the present invention. Sectional drawing which shows one structural example of the conventional lower substrate.

FIG. 13 is a sectional view showing the manufacturing process of the liquid crystal display device according to the eleventh embodiment of the present invention.

14A is a cross-sectional view showing a configuration of a conventional array (lower) substrate, FIG. 14B is a cross-sectional view showing another configuration, and FIGS.
Sectional drawing which shows the bending method of the board | substrate corresponding to this.

15A is a cross-sectional view showing a different configuration of a conventional substrate, and FIGS. 15B and 15C are cross-sectional views showing a corresponding borrow shape of the substrate.

[Explanation of symbols]

 Reference Signs List 6 seal member 7 liquid crystal layer 10 array substrate 11 substrate 12 bending frame 13 mounting component 14 wiring layer 16 switching element 17 pixel electrode 30 counter substrate 31 hard portion (rigid plastic) 32 soft portion (soft plastic) 33 ridge 40 array substrate 41 hard Part (rigid plastic) 42 Soft part (soft plastic) 43 Ridge

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-10-232388 (JP, A) JP-A-9-179106 (JP, A) JP-A 8-278489 (JP, A) JP-A-3-27849 264916 (JP, A) JP-A-5-127154 (JP, A) JP-A-9-80406 (JP, A) JP-A-61-32034 (JP, A) JP-A-7-175053 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/1333 500 G09F 9/00 346

Claims (5)

(57) [Claims] An array substrate on which switching elements for controlling a drive voltage and pixel electrodes are arranged in an array; a counter substrate on which a counter electrode is provided; a liquid crystal layer sandwiched between the array substrate and the counter substrate; In the liquid crystal display device, the counter substrate has a hard portion formed of a hard material having a low coefficient of thermal expansion in a non-planar predetermined shape, and the hard portion has a high coefficient of thermal expansion on at least one surface side with the hard portion as a core. And a soft portion integrally formed of a soft material. 2. The array substrate includes a mounting wiring and a driving circuit integrally formed around a region where the switching element and the pixel electrode are formed, and wherein the switching element and the pixel electrode are formed. 2. A portion around a region to be folded is foldable.
3. The liquid crystal display device according to 1. 3. A folded substrate in which mounting wiring is formed around a region where the switching elements and pixel electrodes arranged in the array are formed, and a region around the switching element is formed to be foldable. 2. The liquid crystal display according to claim 1, further comprising: an array substrate including a mounting substrate provided with a mounting component including a drive circuit connected to the folded portion of the folded substrate and connected to the mounting wiring. apparatus. 4. The array substrate is formed by integrally forming a hard portion formed of a hard material having a low coefficient of thermal expansion into a predetermined shape and a soft material having a high coefficient of thermal expansion on at least one surface side of the hard portion as a core. The liquid crystal display device according to claim 1, further comprising a soft part. 5. An array substrate on which switching elements for controlling a driving voltage are arranged in an array, a counter substrate on which a counter electrode is provided, a liquid crystal layer provided in a closed space between the two substrates,
In the liquid crystal display device, the array substrate is formed by forming a hard material having a low coefficient of thermal expansion in a flat shape on the liquid crystal layer side, and the hard portion is joined to the opposite side of the liquid crystal layer of the hard portion. A hard portion and a soft portion formed with a plurality of cuts extending from the plane opposite to the hard portion to the hard portion, and the array substrate and the counter substrate are spacers having a uniform particle size dispersed between the substrates. A liquid crystal display device, wherein the liquid crystal display device is adhered via a liquid crystal display.