JPH1152351A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the liquid crystal display device having a color filter substrate where trouble in terms of display such as the reflection of external light is not caused, a resin black matrix advantageous in terms of cost is adopted and the high flatness of the substrate is made compatible with the high light shielding performance of the black matrix. SOLUTION: One layer of black matrix 33D1 is formed in the display area 65 of a liquid crystal display element 62, and two layers of black matrices 33D1 and 33D2 are formed in the peripheral part 66, then they are formed so that the sum of the film thickness of the black matices 33D1 and 33D2 in the peripheral part 66 may be nearly equal to the film thickness of color filters 33R, 33G and 33B in the display area 65.

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 having a liquid crystal display element in which liquid crystal is sealed between two upper and lower substrates, and more particularly to a resin black matrix and a color filter on one substrate. The present invention relates to a liquid crystal display device provided.

[0002]

2. Description of the Related Art A conventional liquid crystal display element called a twisted nematic type has a 90 ° twisted helical structure formed by a nematic liquid crystal having a positive dielectric anisotropy between two electrode substrates. Outside the electrode substrate, a pair of polarizing plates are arranged such that their polarization axes (or absorption axes) are orthogonal or parallel to the axes of the liquid crystal molecules adjacent to the electrode substrate (Japanese Patent Publication No. 51-1979). 13666
No.).

[0003] Such a liquid crystal display element having a twist angle of 90 ° has problems in the steepness γ of the change in the transmittance of the liquid crystal layer with respect to the voltage applied to the liquid crystal layer and the viewing angle characteristics. 64 corresponding to the number of electrodes) was the practical limit. However, in order to cope with recent demands for improving the image quality and increasing the amount of display information for liquid crystal display elements, the twist angle α of the liquid crystal molecules sandwiched between a pair of polarizing plates is set to be larger than 180 °, and the voltage applied to this liquid crystal layer is increased. Applied physics letter is to improve the time-sharing drive characteristics and increase the number of time-sharing by detecting the change in the birefringence effect of the liquid crystal layer due to
45, No. 10, 1021, 1984 (Applied Physics Letter,
T. J. Scheffer, J .; Nehring: “A new, highly multip
lexable liquid crystal display "), and a super twisted birefringence effect (SBE) liquid crystal display device has been proposed.

[0004] A liquid crystal display device (ie, a liquid crystal display module) is separated from each other by a predetermined distance such that the surfaces on which various layers such as pixel electrodes and alignment films are laminated face each other.
A pair of substrates made of transparent glass or the like are overlapped, and both substrates are bonded together with a sealing material provided in a frame shape (substantially “b” shape) around the edge between the two substrates, and both inner surfaces of the sealing material are bonded together. A liquid crystal display element (ie, a liquid crystal display panel; an LCD (liquid crystal display)) comprising a liquid crystal sealed between substrates and a polarizing plate provided outside each of the substrates, and a liquid crystal display element disposed below the liquid crystal display element. A backlight for supplying light to the liquid crystal display element, a circuit board for driving the liquid crystal arranged outside the outer peripheral portion of the liquid crystal display element, and a frame-shaped body made of a plastic molded product holding these members; And a metal shield case (metal frame) having an opening for covering the periphery of the liquid crystal display element and exposing the display area.

There are various driving systems in a liquid crystal display device. For example, in a simple matrix type liquid crystal display device,
A large number of strip-shaped transparent electrodes for display are wired in parallel with each other on the opposing surfaces of the two transparent insulating substrates, and the transparent electrodes of both substrates cross each other (orthogonal) when viewed from the direction perpendicular to the substrate surfaces.
To assemble them with a predetermined gap therebetween. Pixels are respectively formed by the intersections of the transparent electrodes on both substrates. A black matrix (light-shielding film) is formed, for example, in a lattice shape in a region other than the pixels on the facing surface of the one substrate, and a color filter is formed in accordance with the intersection region. The black matrix has a function of shielding light, sharpening the outline of each pixel, and improving contrast.

[0006] Liquid crystal display elements, especially STN (Super
Main characteristics required of a so-called color filter substrate on the side where a black matrix and a color filter of a twisted nematic) liquid crystal display element are provided include high flatness of the substrate surface and high light shielding properties of the black matrix.

[0007] The flatness affects the display uniformity of the display screen of the liquid crystal display device. In a color filter substrate, usually, after a black matrix is formed on the surface of the substrate, color filters of, for example, three primary colors of red, green, and blue are partially formed on the black matrix and formed sequentially. Therefore, when the thickness of the black matrix serving as the base increases, a step occurs in the color filter, and the flatness decreases. Therefore, the thickness of the black matrix is desirably small.

The black matrix has the advantage that the higher the light blocking ratio, the higher the display contrast of the display screen. Further, the black matrix provided in the peripheral portion between the display region of the liquid crystal display element and the sealing material has a role of preventing light leakage from the backlight, and is particularly required to have high light shielding. Among the currently used black matrix materials, the ones with the highest light shielding are Cr (chrome) and A
It is a metal film such as l (aluminum). In the case of a resin black matrix made of an organic resin such as an acrylic resin to which a black organic pigment or the like is added, the film thickness must be increased in order to obtain high light shielding.

Therefore, as a color filter substrate having both high flatness of the substrate and high light-shielding properties of the black matrix, a substrate employing a metal black matrix made of a Cr film or the like is widely used at present. For example, Cr
In the case of a black matrix composed of a film, usually, a Cr film is deposited on a surface of a transparent glass substrate by sputtering and then patterned, so that the thickness of the Cr film is 0.1 to
Very thin, about 0.2 μm. On such a thin, C
The light transmittance of the black matrix of the r film is 0.1% or less.

FIG. 13 is a schematic cross-sectional view of a liquid crystal display device provided with a conventional resin black matrix in the vicinity of a sealing material (that is, in the vicinity of a peripheral portion including a display region of the liquid crystal display device).

In FIG. 13, reference numeral 62 denotes a liquid crystal display element;
1 is a transparent glass substrate (color filter substrate), 12 is a transparent glass substrate, 15 and 16 are polarizing plates, 40 is a retardation plate,
33D is a resin black matrix, 33R, 33G,
33B is a red, green and blue color filter, 23 is a protective film for the color filter, 31 and 32 are transparent electrodes, 21, 2
2 is an alignment film, 52 is a sealing material, 50 is a liquid crystal layer, 65 is a display area, and 66 is a peripheral portion between the display area 65 and the sealing material 52 (that is, a light-shielding area outside the display area).

When a resin black matrix is used, the peripheral portion 66 of the liquid crystal display element 62 is increased in light shielding rate without increasing the film thickness as shown in FIG. Black matrix 33D made of resin
Is formed in a solid pattern, and one or a plurality of sets of predetermined one color or RGB color filters are arranged thereon (only the color filters 33G and 33B are shown in FIG. 13), and the resin black matrix 33D is formed. It compensates for the disadvantage of low light-shielding properties.

[0013]

The metal black matrix is advantageous in terms of the high flatness of the substrate and the high light shielding property of the black matrix, but has a high reflectance. Therefore, when the transparent glass substrate provided with the black matrix occupying a large area in the display area is the display screen side (observation side), external light on the display screen side is directed outward (observation side) by the black matrix. There is a problem that the light is reflected, the screen becomes difficult to see (it looks like a mirror), the contrast is reduced, and the display quality is reduced. Further, the metal black matrix is very expensive and inferior in cost.

In order to solve this problem, the use of a resin black matrix can be considered. However, when the thickness of the resin black matrix is reduced in order to obtain high flatness, the light blocking ratio decreases. On the other hand, if the film thickness is increased in order to obtain high light-shielding properties, it is difficult to achieve both high flatness and a high light-shielding ratio, such as a decrease in flatness. In order to compensate for this, as shown in FIG.
Solid resin black matrix 33D at the peripheral portion 66
The pattern of the color filters 33G and 33B is formed on the upper part. By this, the peripheral part 66 of the liquid crystal display element 62 becomes thicker than the display area 65, and a step occurs.
The difference in the thickness of the liquid crystal layer 50 causes a difference in the display quality between the display area 65 and the peripheral portion 66, which causes a reduction in display quality such as uneven display.

An object of the present invention is to adopt a resin black matrix which is advantageous in terms of cost and has no display problem of reflection of external light, and has a high flatness of a substrate and a high light shielding property of a black matrix. An object of the present invention is to provide a liquid crystal display device having a compatible color filter substrate.

[0016]

According to the present invention, in forming a black matrix pattern using a resin-made black matrix, the present invention aims at increasing the light blocking ratio in the peripheral portion of a liquid crystal display element. The thickness of the black matrix pattern is increased only in the peripheral portion. For this purpose, a resin black matrix is formed twice, for example, in the peripheral portion. Further, the total film thickness of the two-layer black matrix in the peripheral portion and the film thickness of the color filter in the display region are made substantially the same so that no step is formed between the peripheral portion and the display region.

That is, according to the present invention, two insulating substrates are overlapped with a predetermined gap therebetween so that the surfaces on which the alignment films are provided face each other, outside the display area and around the edge between the two substrates. The two substrates are adhered to each other by a sealing material provided in a frame shape, a liquid crystal is sealed between the two substrates inside the sealing material, and a resin black matrix and a color filter are mounted on one of the substrates. In a liquid crystal display device having a liquid crystal display element provided with, the film thickness of the black matrix in the peripheral portion between the display region and the sealant is substantially the same as the film thickness of the color filter in the display region. It is characterized by having been formed.

Further, the thickness of the black matrix in a peripheral portion between the display region and the sealing material is larger than the thickness of the black matrix in the display region.

Further, the black matrix in the display area is formed by one layer, and the black matrix in the peripheral portion is formed by two layers.

Further, the thickness of the black matrix in the peripheral portion is substantially the same as the thickness of the color filter in the display area.

Further, the black matrix in the peripheral portion is formed by one layer, and the film thickness of the black matrix in the peripheral portion and the film thickness of the color filter in the display region are substantially the same. And

In the present invention, by increasing the film thickness of the resin black matrix pattern in the peripheral portion of the liquid crystal display element, the light blocking ratio in the peripheral portion can be increased. Further, by making the thickness of the black matrix in the peripheral portion substantially equal to the thickness of the color filter in the display region, no step is generated between the peripheral portion and the display region, thereby suppressing display unevenness. it can.

[0023]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the drawings described below, those having the same functions are denoted by the same reference numerals, and the repeated description thereof will be omitted.

FIG. 1A is a schematic sectional view of the vicinity of a sealing material of a liquid crystal display element provided with a resin black matrix according to an embodiment of the present invention (that is, the vicinity of a peripheral portion including a display area of the liquid crystal display element). FIG. 1B is a cross-sectional view taken along line AA of FIG. 1B, and FIG. 1B is an overall schematic plan view of the liquid crystal display element.

Reference numeral 62 denotes a liquid crystal display element, 11 denotes a transparent glass substrate (color filter substrate), 12 denotes a transparent glass substrate, 1
5, 16 are polarizing plates, 40 is a retardation plate, 33D1 is a first layer resin black matrix, 33D2 is a second layer resin black matrix, 33R, 33G, and 33B are red, green, and blue color filters, and 23 is a color filter. Protective film of filter, 31 and 32 are transparent electrodes, 21 and 22 are alignment films, 52
Is a sealing material, 50 is a liquid crystal layer, 65 is a display area, 66 is a peripheral portion between the display area 65 and the sealing material 52 (that is,
(Light shielding area outside the display area).

In the present embodiment, as shown in FIG. 1A, in order to increase the light blocking ratio of the peripheral portion 66 of the liquid crystal display element 62, the resin black matrices 33D1, 33D2 are formed in the peripheral portion 66. Are formed in a solid pattern to compensate for the low light-shielding property of the resin black matrix. The first-layer resin black matrix 33 is used.
D1 is formed in the same layer as the black matrix 33D1 in the display area 65, that is, in the same material, the same thickness, and the same process. The black matrix 33D2 of the second layer is
It is made of the same material as the first-layer black matrix 33D1, but the total thickness of the first-layer black matrix 33D1 and the second-layer black matrix 33D2, and the color filters 33R, 33G, and 33 in the display area 65.
B is formed to have substantially the same thickness.

That is, in this embodiment, when a black matrix pattern is formed using a resin black matrix, only two layers of the peripheral portion 66 of the liquid crystal display element 62 are formed in order to increase the light blocking ratio. The two-layer black matrix 33D of the peripheral portion 66 is configured so as to prevent the step from being generated between the peripheral portion 66 and the display area 65.
The total thickness of the color filters 1 and 33D2 and the thickness of the color filters 33R, 33G, and 33B in the display area 65 were substantially the same.

FIGS. 2A to 2E are cross-sectional views illustrating the steps of manufacturing the color filter substrate shown in FIG.

First, as shown in FIG. 3A, a first-layer black matrix 33D1 is formed to a thickness of, for example, 1 μm on the display region 65 and the peripheral portion 66 on the transparent glass substrate 11. That is, after a film made of an organic resin such as acryl, epoxy, or polyimide resin to which carbon black, a black pigment or the like is added is formed on the substrate 11, a predetermined pattern such as a lattice pattern is formed by photolithography. The black matrix 33D1 is formed.

Next, as shown in (B), only the peripheral portion 66 is formed in the same manner as the first-layer black matrix 33D1.
A second-layer black matrix 33D2 is formed and patterned. At this time, the sum of the film thicknesses of the two layers of the black matrixes 33D1 and 33D2 in the peripheral portion 66 and the display area 6
5 is formed so that the film thickness of a color filter to be formed thereafter is substantially the same, and a step is not formed between them. Here, the thickness of the color filter is 1.2 μm, and the thickness of the first layer black matrix 33D1 is 1 μm, so that the thickness of the second layer black matrix 33D2 is 0.2 μm. The thickness of the black matrix is adjusted when the black matrix is applied by, for example, rod coating, by adjusting the wire diameter.
In the case of spin coating, adjustment is performed by adjusting the application amount, spin conditions, and the like. Also, the second-layer black matrix 33
D2 is formed before the color filter to prevent the residue when the second-layer black matrix 33D2 is formed on the color filter from remaining.

Next, as shown in (C) and (D), a red color filter 33R, a green color filter 33G, and a blue color filter 33B are sequentially formed for each color. That is, first, a dyeing base material such as an acrylic resin is formed on the surface of the display region 65 of the substrate 11 on which the black matrix 33D1 is formed, and the dyeing base material other than the red color filter forming region is removed by photolithography. Thereafter, the dyed base material is dyed with a red dye and subjected to a fixing treatment to form a red color filter 33R. Next, by performing similar steps, a green color filter 33G and a blue color filter 33B are sequentially formed. After forming the dyed base material, instead of dyeing with a dye, patterning may be performed sequentially by photolithography using, for example, a photocurable negative resist to which an organic pigment adapted to each color tone is added.

Finally, as shown in (E), in order to prevent elution of impurities from the colored resin and to secure flatness, acrylic, epoxy resin or the like is applied by spin coating, roll coating, transfer printing, or the like. Then, heat treatment was performed to cure the film, thereby forming a protective film (flattening film) 23 for the color filter. Next, a transparent conductive film containing indium oxide as a main component is formed thereon by a sputtering method to form a transparent electrode 31, and one of two substrates on which a liquid crystal display element is formed is completed. did. Thereafter, an alignment film 21 is formed on the transparent electrode 31 of the substrate 11,
The alignment film 21 was subjected to an alignment process.

The other substrate is formed by forming a transparent electrode and an alignment film on a transparent glass substrate. These two substrates are bonded together via a sealing material 52 as shown in FIG. The liquid crystal 5 is provided inside the sealing material 52 between the substrates 11 and 12.
0 is enclosed.

FIG. 1 assembled in this manner
In the liquid crystal display element 62 shown in (A) and (B), the black matrix 33D1
Since two layers of 33D2 are provided, the light shielding rate of the peripheral portion 66 is high. That is, the light from the backlight (see FIG. 10) that supplies light from the back of the liquid crystal display element 62
, And light leakage can be prevented by the two layers of black matrices 33D1 and 33D2, and a high contrast between the display region 65 and the peripheral portion 66 can be obtained.
Display quality has been improved. By improving the light-shielding property of the peripheral portion 66, the width of the so-called frame portion of the liquid crystal display element 62 can be reduced, which is advantageous in reducing the outer dimensions of the liquid crystal display module. Furthermore, since the total thickness of the black matrices 33D1 and 33D2 in the peripheral portion 66 is substantially the same as the thickness of the color filters 33R, 33G, and 33B in the display region 65, there is no step in the peripheral portion of the color filter substrate 11. As is clear from the comparison between FIG. 1A and FIG. 13, there is no difference in the thickness of the liquid crystal layer 50 inside the liquid crystal display element 62 in which the two substrates 11 and 12 are bonded to each other, and display unevenness occurs. Did not occur.

In this embodiment, in the peripheral portion 66, a resin black matrix 33D1 having a thickness of 1 μm is formed.
And resin black matrix 33D2 having a thickness of 0.2 μm
, The color filter 33R of the display area 65,
Although the film thickness was substantially the same as the film thickness of 1.2 μm of 33G and 33B, two layers were not necessarily formed, but one layer of a resin black matrix having the same film thickness as the color filter was formed only in the peripheral portion 66. You may.

Hereinafter, a simple matrix type liquid crystal display device and a liquid crystal display module to which the present invention can be applied will be described with reference to FIGS.

FIG. 3 shows a liquid crystal display element 6 to which the present invention can be applied.
2 when viewed from above, the alignment direction of liquid crystal molecules on the electrode substrate (eg, rubbing direction), the twist direction of liquid crystal molecules, the polarization axis (or absorption axis) direction of the polarizing plate, and the optics of a member that provides a birefringence effect. FIG. 3 is a perspective view of a main part of the liquid crystal display element 62.

The twist direction 10 and the twist angle θ of the liquid crystal molecules
Are the rubbing direction 6 of the alignment film 21 on the upper electrode substrate 11, the rubbing direction 7 of the alignment film 22 on the lower electrode substrate 12, and the positive dielectric anisotropic material sandwiched between the upper electrode substrate 11 and the lower electrode substrate 12. It is determined by the type and amount of the optical rotatory substance added to the nematic liquid crystal layer 50 having the property.

In FIG. 4, in order to align the liquid crystal molecules in a twisted helical structure between the two upper and lower electrode substrates 11 and 12 sandwiching the liquid crystal layer 50, for example, a transparent upper layer made of glass is used. A method of rubbing the surfaces of the alignment films 21 and 22 made of, for example, an organic polymer resin made of polyimide on the lower electrode substrates 11 and 12 in contact with the liquid crystal in one direction with a cloth, for example, is called a rubbing method. ing. The rubbing direction at this time, that is, the rubbing direction, the rubbing direction 6 for the upper electrode substrate 11, and the rubbing direction 7 for the lower electrode substrate 12 are the alignment directions of the liquid crystal molecules. The two upper and lower electrode substrates 1 thus oriented are treated.
The _first and second electrode substrates 11 and 12 are notched for injecting a liquid crystal, with the gaps d1 therebetween so that the rubbing directions 6 and 7 intersect each other at approximately 180 degrees to 360 degrees. When a nematic liquid crystal having a positive dielectric anisotropy and a predetermined amount of an optical rotatory substance is sealed in the gap between them, a liquid crystal molecule is adhered. Has a helical molecular arrangement with a twist angle θ in the figure between the electrode substrates. 31 and 32 are, for example, indium oxide or ITO, respectively.
(Indium Tin Oxide) transparent upper and lower electrodes. A member that provides a birefringence effect above the upper electrode substrate 11 of the liquid crystal cell 60 configured as described above (hereinafter, referred to as a birefringent member. Fujimura et al., "Phase Difference Film for STN-LCD", Magazine Electronic Materials, 1991, Feb. Monthly Pages 37-41)
The upper and lower polarizing plates 15 and 16 are provided with the member 40 and the liquid crystal cell 60 interposed therebetween.

The twist angle θ of the liquid crystal molecules in the liquid crystal 50 can take a value in the range of 180 ° to 360 °, and is preferably 200 ° to 300 °. From the practical viewpoint of avoiding the state in which the state becomes an orientation that scatters light and maintaining excellent time division characteristics, the range of 230 to 270 degrees is more preferable. This condition basically acts to make the response of the liquid crystal molecules to the voltage more sensitive and to realize excellent time division characteristics. In order to obtain excellent display quality and the refractive index anisotropy [Delta] n ₁ of the liquid crystal layer 50 a product [Delta] n ₁ of the thickness d ₁
D ₁ is preferably set in the range of 0.5 μm to 1.0 μm, and more preferably in the range of 0.6 μm to 0.9 μm.

The birefringent member 40 functions to modulate the polarization state of the light transmitted through the liquid crystal cell 60, and converts the liquid crystal cell 60, which could only display in a colored state, into a monochrome display. Thus the birefringent member 40 refractive index anisotropy [Delta] n ₂ and is extremely important product [Delta] n ₂ · d ₂ of a thickness d _2, preferably 0.8μm from 0.4 .mu.m, more preferably 0.5μm To a range of 0.7 μm.

Further, since the liquid crystal display element 62 uses elliptically polarized light due to birefringence, the axes of the polarizing plates 15 and 16 and the optical axis thereof when a uniaxial transparent birefringent plate is used as the birefringent member 40. And the electrode substrate 11 of the liquid crystal cell 60,
The relationship between the twelve liquid crystal alignment directions 6 and 7 is extremely important.

The operation and effect of the above relationship will be described with reference to FIG. FIG. 3 shows an axis of a polarizing plate, an optical axis of a uniaxial transparent birefringent member when the liquid crystal display device having the configuration of FIG. 4 is viewed from above,
FIG. 3 shows a relationship between a liquid crystal molecular axis arrangement direction of an electrode substrate of a liquid crystal cell.

In FIG. 4, 5 is the optical axis of the uniaxial transparent birefringent member 40, 6 is the liquid crystal molecular axis arrangement direction of the birefringent member 40 and the adjacent upper electrode substrate 11, and 7 is the lower electrode substrate 12 The liquid crystal alignment direction, 8 is the absorption axis or polarization axis of the upper polarizer 15, 9 is the absorption axis or polarization axis of the lower polarizer 16, and the angle α is uniaxial birefringence with the liquid crystal alignment direction 6 of the upper electrode substrate 11. The angle between the optical axis 5 of the member 40 and the angle β is the angle between the absorption axis or the polarization axis 8 of the upper polarizer 15 and the optical axis 5 of the uniaxial transparent birefringent member 40, and the angle γ is the lower polarizer 16 Between the absorption axis or polarization axis 9 and the liquid crystal alignment direction 7 of the lower electrode substrate 12.

Here, how to measure the angles α, β, and γ in this specification is defined. In FIG. 8, a description will be given by taking an example of an intersection angle between the optical axis 5 of the birefringent member 40 and the liquid crystal alignment direction 6 of the upper electrode substrate. The intersection angle between the optical axis 5 and the liquid crystal alignment direction 6 is shown in FIG.
Can be represented by φ ₁ and φ ₂ as shown in the following, but the smaller angle of φ ₁ and φ ₂ is adopted in this specification. That is, since φ ₁ <φ ₂ in FIG. 8A, φ ₁ is defined as the intersection angle α between the optical axis 5 and the liquid crystal alignment direction 6.
In FIG. 8B, since φ ₁ > φ _2, φ ₂ is the intersection angle α between the optical axis 5 and the liquid crystal alignment direction 6. Of course, either case may be adopted when φ ₁ = φ ₂ .

In a liquid crystal display device, the angles α, β, and γ are extremely important.

The angle α is preferably 50 to 90 degrees, more preferably 70 to 90 degrees, the angle β is preferably 20 to 70 degrees, more preferably 30 to 60 degrees, and the angle γ is preferably It is desirable to set the angle between 0 ° and 70 °, more preferably between 0 ° and 50 °.

If the twist angle θ of the liquid crystal layer 50 of the liquid crystal cell 60 is in the range of 180 degrees to 360 degrees, the above-described angle can be obtained regardless of whether the twist direction 10 is clockwise or counterclockwise. α, β, and γ may be within the above ranges.

In FIG. 4, the birefringent member 40 is provided between the upper polarizing plate 15 and the upper electrode substrate 11, but instead of this position, the lower electrode substrate 12 and the lower polarizing plate 16 are provided.
And may be arranged between them. This case corresponds to a case where the entire configuration of FIG. 4 is inverted.

FIG. 5 is a diagram showing a specific example of the twist angle θ and the like. As shown in the figure, the twist angle θ of the liquid crystal molecules is 240 degrees, and as the uniaxial transparent birefringent member 40, a liquid crystal cell having a parallel orientation (homogeneous orientation), that is, a twist angle of 0 degrees was used. Here, the liquid crystal layer thickness d (μm) and the helical pitch p (μ
The ratio d / p of m) was 0.67. Alignment films 21, 22
Used was formed of a polyimide resin film and rubbed. The tilt angle (pretilt angle) at which the alignment film subjected to the rubbing treatment causes the liquid crystal molecules in contact with the alignment film to be tilt-aligned with respect to the substrate surface is 4 degrees. Δn ₂ · d ₂ of the uniaxial transparent birefringent member 40 is about 0.6 μm. On the other hand, Δn ₁ ·· of the liquid crystal layer 50 having a structure in which the liquid crystal molecules are twisted 240 degrees.
d ₁ is about 0.8 μm.

At this time, by setting the angle α to about 90 degrees, the angle β to about 30 degrees, and the angle γ to about 30 degrees, the voltage applied to the liquid crystal layer 50 via the upper and lower electrodes 31 and 32 is reduced. When the voltage is lower than the threshold value, light opacity, that is, black, and when the voltage exceeds a certain threshold value, light transmission, that is, white black and white display can be realized. Also, the axis of the lower polarizing plate 16 is set at 50 degrees from the above position.
When rotated by 90 degrees from the degree, white when the voltage applied to the liquid crystal layer 50 was equal to or less than the threshold value, and black when the voltage was equal to or more than the threshold value, black and black was displayed in reverse.

FIG. 6 shows a change in contrast during time-division driving at 1/200 duty when the angle α is changed in the configuration of FIG. When the angle α is around 90 degrees, the contrast is extremely high, but the contrast decreases as the angle α deviates from this angle. In addition, when the angle α is small, both the lighted part and the non-lighted part become bluish, and when the angle α is large, the non-lighted part becomes purple and the lighted part becomes yellow. The results are almost the same for the angles β and γ. However, in the case of the angle γ, when the image is rotated from 50 degrees to nearly 90 degrees, a black-and-white display is reversed.

FIG. 7 is a diagram showing another specific example such as the twist angle θ. The basic structure is the same as the specific example shown in FIG.
However, the twist angle of the liquid crystal molecules of the liquid crystal layer 50 is 260 degrees,
The difference is that Δn ₁ · d ₁ is about 0.65 μm to 0.75 μm. Δn ₂ · d ₂ of the parallel alignment liquid crystal layer used as the uniaxial transparent birefringent member 40 is about 0.5
8 μm. The thickness d ₁ (μm) of the liquid crystal layer and the helical pitch p (μm) of the nematic liquid crystal material to which the optically active substance is added
And d / p = 0.72.

At this time, by setting the angle α to about 100 degrees, the angle β to about 35 degrees, and the angle γ to about 15 degrees, the same monochrome display as in the first specific example was realized. As in the first specific example, it is possible to perform the reverse black and white display by rotating the position of the axis of the lower polarizing plate by 50 to 90 degrees from the above value. The tendency of the angles α, β, and γ to shift is almost the same as in the first specific example.

In each of the above embodiments, a parallel alignment liquid crystal cell having no twist of liquid crystal molecules was used as the uniaxial transparent birefringent member 40, but a liquid crystal layer in which liquid crystal molecules were twisted by about 20 to 60 degrees was used. There is less color change due to the angle. This twisted liquid crystal layer is formed by sandwiching the liquid crystal between substrates in which the alignment processing directions of a pair of alignment-processed transparent substrates cross a predetermined twist angle, similarly to the liquid crystal layer 50 described above. You. In this case, the direction of the bisecting angle between the two alignment processing directions sandwiching the twisted structure of the liquid crystal molecules may be treated as the optical axis of the birefringent member. Further, a transparent polymer film may be used as the birefringent member 40 (in this case, a uniaxially stretched one is preferable). In this case, as the polymer film, PET (polyethylene terephthalate), an acrylic resin film, and polycarbonate are effective.

In the above embodiment, the single birefringent member is used. However, in FIG. 4, in addition to the birefringent member 40, another birefringent member is provided between the lower electrode substrate 12 and the lower polarizing plate 16. Refraction members can also be inserted. In this case, Δn ₂ · d ₂ of these birefringent members may be readjusted.

However, as shown in FIG.
Red, green, blue color filters 33R, 33G, 33 on top
B. By providing the light-shielding film 33D between the filters, multi-color display becomes possible. FIG. 7 shows the relationship among the arrangement direction of the liquid crystal molecules, the twist direction of the liquid crystal molecules, the direction of the axis of the polarizing plate, and the optical axis of the birefringent member in the above specific example.

In FIG. 9, each filter 33
On the R, 33G, 33B and the light shielding film 33D, a smooth layer 23 made of an insulator is formed to reduce the influence of these irregularities, and then an upper electrode 31 and an alignment film 21 are formed.

FIG. 10 is an exploded perspective view showing a liquid crystal display element 62, a driving circuit for driving the liquid crystal display element 62, and a liquid crystal display module 63 in which light sources are compactly integrated. IC 34 for driving liquid crystal display element 62
Is mounted on a frame-shaped printed circuit board 35 having a window for fitting the liquid crystal display element 62 in the center. The printed circuit board 35 in which the liquid crystal display element 62 is fitted is fitted in the window of the frame 42 made of plastic mold,
The metal frame 41 is overlaid on this, and the claw 43 is bent into the cutout 44 formed in the frame 42 to fix the frame 41 to the frame 42.

A cold cathode fluorescent lamp 36 disposed at the upper and lower ends of the liquid crystal display element 62; a light guide 37 made of an acrylic plate for uniformly irradiating the liquid crystal display cell 60 with light from the cold cathode fluorescent lamp 36; A reflecting plate 38 formed by applying a white paint to a metal plate and a milky white diffusing plate 39 for diffusing light from the light guide 37 are fitted into the window of the frame 42 from the back side in the order shown in FIG. It is. An inverter power supply circuit (not shown) for lighting the cold cathode fluorescent lamp 36 is provided with a concave portion (not shown) provided on the right rear portion of the frame member 42.
5. ). Diffusing plate 3
9, light guide 37, cold cathode fluorescent lamp 36 and reflector 38
The tongue piece 46 provided on the reflection plate 38 is
Is fixed by folding it into the fore-edge 47 provided in the front end.

FIG. 11 is a block diagram of a laptop personal computer using the liquid crystal display module 63 as a display unit, and FIG. 12 is a diagram showing a state where the liquid crystal display module 63 is mounted on a laptop personal computer 64. In this laptop computer 64, the microprocessor 4
9 is applied to the liquid crystal display module 63 by the liquid crystal driving semiconductor IC 34 via the control LSI 48.
Is to be driven.

Although the present invention has been specifically described based on the embodiments, the present invention is not limited to the above-described embodiments, and it is needless to say that various modifications can be made without departing from the gist of the present invention. It is. For example, the present invention is applicable to a simple matrix type liquid crystal display device, a vertical electric field type or a horizontal electric field type active matrix type liquid crystal display device as long as the liquid crystal display device has a resin black matrix and a color filter. Alternatively, it is needless to say that the present invention can be applied to a COG (chip-on-glass) liquid crystal display device. In addition, the present invention can be applied to a liquid crystal display device having various shapes of black matrices and color filters, for example, a lattice-shaped or band-shaped black matrix, a band-shaped color filter, and the like.

[0063]

As described above, according to the present invention,
It is possible to improve the light blocking ratio in the peripheral portion of the liquid crystal display element, prevent light leakage of the backlight in the peripheral portion, and improve the display quality. Further, since there is no step between the display area of the liquid crystal display element and the peripheral portion, it is possible to prevent display deterioration such as uneven display on the display screen. Further, since a resin black matrix is employed, costs can be reduced as compared with the case where a metal black matrix is employed.

[Brief description of the drawings]

FIG. 1A is a schematic sectional view of the vicinity of a display region and a peripheral portion of a liquid crystal display element according to an embodiment of the present invention (A in FIG. 1B);
-B is a schematic plan view of the entire liquid crystal display element.

2 (A) to 2 (E) are cross-sectional views showing a manufacturing process of the color filter substrate shown in FIG.

FIG. 3 shows an example of the relationship among the arrangement direction of liquid crystal molecules, the twist direction of liquid crystal molecules, the direction of the axis of a polarizing plate, and the optical axis of a birefringent member in a simple matrix type liquid crystal display device to which the present invention can be applied. FIG.

FIG. 4 is an exploded perspective view of a main part of an example of a liquid crystal display element.

FIG. 5 is an explanatory view showing a relationship among a twist direction of liquid crystal molecules, a direction of an axis of a polarizing plate, and an optical axis of a birefringent member in another example of a liquid crystal display device.

6 is a graph showing contrast and transmitted light color-intersection angle α characteristics of the example of FIG. 3 of the liquid crystal display element.

FIG. 7 is an explanatory view showing the relationship among the alignment direction of liquid crystal molecules, the twist direction of liquid crystal molecules, the direction of the axis of a polarizing plate, and the optical axis of a birefringent member in a liquid crystal display element of yet another example.

FIG. 8 is a diagram for explaining how to measure the intersection angles α, β, and γ.

FIG. 9 is a partially cutaway perspective view of an example of an upper electrode substrate portion of a liquid crystal display element.

FIG. 10 is an exploded perspective view of an example of a liquid crystal display module.

FIG. 11 is a block diagram of an example of a laptop personal computer.

FIG. 12 is a perspective view of an example of a laptop personal computer.

FIG. 13 is a schematic cross-sectional view showing a display region and a vicinity of a peripheral portion of a conventional liquid crystal display element.

[Explanation of symbols]

11 ... Transparent glass substrate (color filter substrate), 12 ...
Transparent glass substrate, 15, 16: polarizing plate, 21, 22, alignment film, 23: protective film, 31, 32: transparent electrode, 33D1
... First-layer resin black matrix, 33D2... Second-layer resin black matrix, 33R, 33G, 33B.
Red, green, blue color filters, 40 ... retarder, 5
0: liquid crystal layer, 52: sealing material, 62: liquid crystal display element, 6
5: display area, 66: peripheral area.

Claims (5)

[Claims] An insulating substrate is overlapped with a predetermined gap so that surfaces on which alignment films are provided face each other, and is formed in a frame shape outside a display area and around an edge between the two substrates. A liquid crystal in which the two substrates are adhered to each other with a sealing material provided, a liquid crystal is sealed between the two substrates inside the sealing material, and a resin black matrix and a color filter are provided on one of the substrates. In a liquid crystal display device having a display element, a thickness of the black matrix in a peripheral portion between the display region and the sealant is substantially equal to a thickness of the color filter in the display region. Characteristic liquid crystal display device. 2. An insulating substrate according to claim 1, wherein the two insulating substrates are overlapped with a predetermined gap therebetween so that the surfaces on which the alignment films are provided face each other, and formed in a frame shape outside the display area and around the edge between the two substrates. A liquid crystal in which the two substrates are adhered to each other with a sealing material provided, a liquid crystal is sealed between the two substrates inside the sealing material, and a resin black matrix and a color filter are provided on one of the substrates. In the liquid crystal display device having a display element, a thickness of the black matrix in a peripheral portion between the display region and the seal material is formed to be thicker than a thickness of the black matrix in the display region. Liquid crystal display device. 3. The black matrix in the display area is formed by one layer, and the black matrix in the peripheral portion is formed by two layers.
The liquid crystal display device as described in the above. 4. The liquid crystal display device according to claim 2, wherein the thickness of the black matrix in the peripheral portion is substantially equal to the thickness of the color filter in the display area. 5. The black matrix in the peripheral portion is formed in one layer, and the thickness of the black matrix in the peripheral portion and the thickness of the color filter in the display area are formed to be substantially the same. The liquid crystal display device according to claim 2, wherein