JP2002116439A - Liquid crystal display element - Google Patents

Abstract

(57) [PROBLEMS] To improve the contrast of a liquid crystal display device and a device in a mode such as an OCB type liquid crystal display device which performs display by controlling the birefringence of a liquid crystal layer. SOLUTION: The reflection of light inside an element is reduced. The reflected light is reduced based on the difference in the refractive index of the material of the boundary surface of each element. Internal light such as backlight light is made to be orthogonal to the substrate surface as much as possible. Specifically, for example, the material on the liquid crystal layer side of the black matrix, active element, and wiring formed on at least one of the substrates is a light absorber.

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 used for a liquid crystal television receiver, a portable OA device and the like.

[0002]

2. Description of the Related Art A liquid crystal display element generally used is a display element using a TN (twisted nematic) liquid crystal. In recent years, various display devices (including those called π cells) using an OCB (optically compensated bend mode) liquid crystal have been variously reported, which provide a high-speed response and a wide viewing angle. There are benefits.

The OCB type liquid crystal and the display element and display device using the same are described in, for example, "IEICE Technical Report EDI98-144, p. 199", JP-A-7-84254 and JP-A-9-84254. Since it is a well-known technique described in -96790 or the like, detailed description thereof will be omitted.

A general OCB type liquid crystal display device has a structure as shown in FIG. That is, the backlight unit 103, which is a white light source, is disposed on the back surface of the liquid crystal panel 113, similarly to the elements using many types of liquid crystal. The backlight unit includes a light guide plate 101, side lights 102, and the like. Then, a liquid crystal (material) 114 having a predetermined thickness is held between two upper and lower substrates (111, 107) (sandwiched if there are two substrates).
A color filter 112 for each color (red R, green G, blue B) is formed on one substrate 111 corresponding to the pixel. The other substrate is an active matrix substrate on which active elements such as the TFT 108 are formed. Furthermore, so-called black matrices 201 and 202 are formed between the color filters of each color.
The material of this black matrix is the substrate side 202
Is chromium oxide, and the liquid crystal side 201 is metallic chromium. Furthermore, transparent electrodes 109 made of ITO are formed on the upper and lower liquid crystal panels as means for applying a voltage.

[0005] However, since these are well-known techniques, further detailed description will be omitted, and portions related to the present invention will be described below.

Incidentally, the OCB type liquid crystal element performs display by changing the birefringence of the liquid crystal layer by applying a voltage and changing the retardation (optical phase difference). For this reason, in the above-described TN type liquid crystal element, the rubbing for determining the alignment direction of the liquid crystal is in a twisted state in which the direction is different by 90 ° between the upper and lower substrates. It is rubbing.

Further, optical compensation films 106 and 105 are arranged outside the upper and lower substrates. As the film, for example, an optical compensation film 106 in which discotic liquid crystals are hybrid-aligned and an optical compensation film 105 stretched in a biaxial direction are used. Furthermore, a polarizing plate 104 is disposed on the outermost side. The polarization axis of this polarizing plate is at 45 ° with respect to the rubbing direction for aligning the liquid crystal.
Often, they are staggered. At this time, for example, the upper polarizing plate is shifted by + 45 ° and the lower polarizing axis is shifted by −45 °. At this time, the angle between the upper and lower polarizing plates is 90 °.

The above is a so-called transmission type case mainly used for a liquid crystal television display device, a word processor and the like. In the reflection type, which is often used in portable devices, a reflection plate is provided instead of the backlight unit, and there are some differences also in the lower retardation film and the like. However, these differences are also so-called well-known technologies, and thus description thereof is omitted.

[0009]

However, in the OCB type liquid crystal display device having the above-mentioned structure, first of all, in recent years, as the demand for the display characteristics has been enhanced, the contrast (luminance at the time of bright display / dark display) has been increased. Is not necessarily sufficient.

Second, in the case of black display, the crossing angle of the polarizing plate differs depending on the viewing angle, so that a bluish tint occurs.
This cannot be ignored even under the recent demand for the display characteristics not to be deteriorated depending on the viewing angle of the user.

Third, it is desirable that the brightness of the display surface and the like be further improved.

[0012] For this reason, there has been a demand for the development of a technique for achieving a higher contrast ratio, no coloring depending on the viewing angle, and other favorable display characteristics.

[0013]

SUMMARY OF THE INVENTION The present invention has been made as a result of research for solving the above problems. A liquid crystal display element (including a liquid crystal switch or a liquid crystal logic) including, in principle, a liquid crystal of a mode for displaying figures and calculation results by controlling the amount of birefringence, as well as the OCB type, is sandwiched between two substrates. In the element), items that could hinder achievement of the above-mentioned problems were found and eliminated one by one, and as a result, the above-mentioned problems were solved. Specifically, it is performed as follows.

In one invention group, the amount of reflected light at each part constituting the liquid crystal display element is reduced. That is,
In principle, a liquid crystal (layer) in a mode for displaying by controlling the amount of birefringence is sandwiched between two substrates. In a special case, a liquid crystal (layer) and an upper boundary resin film are provided on one substrate. In the liquid crystal display element, at least one of the substrates has
A so-called black matrix and a light-shielding layer as a light-shielding part (a part that does not allow light to pass) around the display part are formed.
At least a part of the light-shielding layer (a part may be left for manufacturing reasons or the like, but preferably all of the light-shielding layer is preferably used) is not a material having a simple light-shielding property, and at least the liquid crystal layer side is used as a light absorber. I have.

As a result, backlight light and the like from the back side of the substrate as viewed from the user are reflected toward the lower substrate side on the liquid crystal surface side surface of the light-shielding layer provided on the upper substrate, and are reflected on the upper substrate side on the lower substrate side. Is reflected again to escape to the display surface side, and thus, even though the display is dark, the reflected light enters the user's eyes, thereby preventing the contrast from being adversely affected.

On at least one of the substrates of the liquid crystal display element, in particular, on the lower side on the side opposite to the user, an active element made of a white or highly reflective material such as polycrystalline silicon or a metal wiring with good reflection is formed. An active matrix substrate. For this reason, at least one part of the wiring on the at least one active matrix substrate (if both are the active matrix substrates, in principle, both substrates) and at least a part of the upper surface of the active element (partly due to manufacturing reasons). However, it is possible that a light absorber layer or a thin film band made of a light absorber is formed on the liquid crystal side.

This prevents the light from the opposite substrate side, particularly the reflected light, from being reflected on the reflection side substrate and finally entering the user's eyes, thereby preventing the contrast from being lowered.

In one invention group, in a similar liquid crystal display device, reduction of interfacial reflection occurring at a boundary surface (especially in a region where light passes) of a substrate, a transparent electrode, a retardation film, etc. is intended. In particular, attention is paid to the fact that reflected light reaches the user's eyes at the time of dark display, reduces contrast, prevents or reduces coloring in dark display, and focuses on these. Light is reduced. That is, a transparent electrode is formed on at least one of the substrates, and a film having an intermediate refractive index between the substrate and the transparent electrode is formed on the surface of the transparent electrode, or an anti-reflection film is formed. Anti-reflection treatment is performed.

In addition, at least one (in principle, both)
At least one retardation film on the substrate (in principle, 2
The retardation film has an interface reflectance of 1% or less. In addition, the properties of the retardation film are devised.

In one invention group, in a similar liquid crystal display element, a light absorber and a color filter are formed on an active matrix substrate on which active elements and wirings are formed. ) Is also provided over the active elements and wiring formed outside the pixel, thereby absorbing the complementary color light of the color filter and reducing the reflected light without forming the light absorber layer composed of the resin matrix. ing.

Also, an antireflection film is formed on the interface between the upper and lower substrates and the air layer.

In one invention group, in a similar liquid crystal display element, the backlight light is condensed in the vicinity of the front or in the direction facing the user, or the light is condensed and reflected as such. Means and light collecting (reflecting) means.
This minimizes the light that should not reach the user's eyes and goes to the light-impermeable portion, such as the back side of the black matrix of the substrate, the active element of the active matrix substrate, and the liquid crystal side of the wiring, etc. Thus, the light use efficiency is improved while preventing the light from being finally reflected by the user or the like to the user's eyes and causing a decrease in contrast.

In one invention group, the retardation of the liquid crystal in black display is not zero.

In one invention group, the liquid crystal is of the OCB mode.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on its embodiments.

(First Embodiment) The present embodiment relates to the prevention of reflection on the outer surface of a black matrix.

FIG. 2 is a sectional view of the liquid crystal display device of the present embodiment. As shown in this figure, this liquid crystal display element
A liquid crystal panel having liquid crystal sandwiched between substrates, the liquid crystal panel has a retardation film on its outside, a color filter is formed on one of the substrates, and the other substrate is a TFT.
The basic structure in which elements and the like are formed and a backlight unit is disposed on the back surface of the liquid crystal panel is the same as the conventional structure shown in FIG. However, the resin BM is applied to the black matrix 200 formed as a light shielding layer on the color filter substrate on the upper (user side) substrate in the figure.
(A black matrix made of resin).
Here, the resin BM is an acrylic resin containing a black pigment.

According to the study of the present inventor, in a liquid crystal display device, a black matrix in the form of a lattice (a so-called mosaic) is provided between pixels in order to clarify colors between pixels, shield light from a TFT silicon film, and the like. However, it has been found that backlight light is reflected on the back surface of the black matrix (light-shielding layer), and this causes a significant decrease in contrast.

Hereinafter, this will be conceptually described with reference to FIG. For the reasons described above, generally the black matrix 60
1 is made of a laminated structure of chromium oxide and chromium.
Then, black chromium oxide 202 having excellent color clarity is deposited on the inner surface (liquid crystal side) on the upper substrate side, and chromium 201 having good metallic luster with good light-shielding properties is laminated thereunder. For this reason, the surface of the black matrix that is in contact with the liquid crystal layer has metallic luster, and inevitably reflects light going upward from inside to the inside.

In the original design, light incident on the liquid crystal panel from the backlight passes through the lower polarizing plate 104, the lower retardation films 105 and 106, and then passes through the liquid crystal layer only once. Further upper retardation films 106, 1
05, it is designed to pass through the upper polarizing plate 104 and go out. This is schematically shown in FIG. 3 (1). By the way, in a mode using birefringence such as an OCB type liquid crystal element, the total amount of retardation received by light when the light passes is controlled.

When black display is performed in this embodiment,
The condition is such that the retardation of the liquid crystal layer in the state where the voltage for black display is applied is offset by the retardation of the retardation film disposed on the upper and lower sides of the substrate. Here, the upper and lower polarizers are in a crossed Nicols state that are orthogonal to each other.

However, when the back surface 201 of the black matrix has metallic luster as shown in FIGS. 1 and 3, light is reflected here. In the lower substrate in the figure, there are also portions having white or metallic luster such as TFTs and wirings.
There is a small amount of reflection on the surface of the TO transparent electrode.

For this reason, the light reflected downward on the back surface of the black matrix on the upper substrate and further reflected on the TFTs, wirings, etc. on the lower substrate goes upward again, and a considerable proportion (amount) of the light passes directly to the front. Into the eyes of the observer or user. This is shown in FIG. 3 (2).
That is, since this light passes through the liquid crystal layer 114 three times, it receives three times the normal retardation. As a result, the retardation cannot be completely compensated for by the upper and lower retardation films, and light leaks upward.

In the case of a liquid crystal display device, the ratio of the projected area of the black matrix, active elements and wirings to the display surface is quite large, and their reflectance is also large. This was one of the causes of the decrease in the contrast of the display surface. Specifically, in the present embodiment, the retardation of the upper and lower retardation films is 30 nm,
The retardation of the liquid crystal layer is 60 nm. By the way, usually, the retardation of the film and the liquid crystal cancel each other,
When the light passes through the liquid crystal layer three times, the retardation of the liquid crystal layer becomes 180 nm (= 60 nm × 3), and the retardation of 120 nm remains even after passing through the film. This acts as a λ / 4 plate, and the transmittance of this component reaches as high as 50% of the maximum white.

Incidentally, the phenomenon or problem that the reflected light lowers the contrast is remarkable in a mode in which the liquid crystal layer has birefringence in a black state and the retardation of the liquid crystal layer is not zero. If the retardation value is 0, no problem occurs even when the light passes through the liquid crystal layer a plurality of times. OC
In the B-type liquid crystal display element, there is retardation of the liquid crystal layer at a black voltage, and the retardation of the film is adjusted to compensate for this. In such an element, it is desirable to consider interface reflection. Further, in the case of such a configuration, a retardation film is attached to the upper and lower sides of the panel, and the retardation in the front direction of the retardation film is not zero. For example, a vertical alignment type liquid crystal display element performs black display in a vertical alignment state. At this time, there is almost no birefringence of the liquid crystal layer, and no retardation film having retardation is attached to the outside of the panel. Therefore, in the vertical alignment type liquid crystal, the problem of a decrease in contrast due to the reflected light described above does not substantially occur.

In a TN (twisted nematic) type liquid crystal element, which has conventionally been the mainstream, an optical wavefront propagates along the twist direction of liquid crystal molecules using optical rotation instead of adjusting birefringence. For this reason, the decrease in contrast due to the reflected light described above does not substantially occur.

As described above, in the liquid crystal display device of the present embodiment, as shown in FIG. 2, the black matrix is made of a resin in which a black pigment is dispersed (hereinafter, the material forming the black matrix is also referred to as a resin BM). Although formed, unlike the conventional black matrix, this resin BM is black not only on the upper surface but also on the back surface. Therefore, there is almost no reflection of light going upward from the inside. As a result, in the case of black display, the backlight is hardly reflected on the back surface of the black matrix, reflected on the upper surface of the lower substrate again, and directed toward the user, and the contrast is greatly improved.

With the liquid crystal display device of the present embodiment, a contrast of 200 was obtained.

It should be noted that, as a reminder, it goes without saying that the vividness and the like of each color did not deteriorate during color display or the like. Also, unlike the prior art, it is not necessary to form the black matrix in two separate steps, which does not lead to an increase in cost and also does not cause a shift between the upper and lower layers, which is preferable from these aspects.

Next, as understood from the above description, the point of this embodiment is to reduce the reflection on the back surface of the black matrix. Therefore, the black matrix is not limited to the resin BM. Not something. In other words, instead of a general chromium oxide-chromium laminated structure, the process becomes somewhat troublesome, but a triple laminated structure of chromium oxide-chromium-chromium oxide may be used. Although it is necessary to form the chromium oxide layer to be somewhat thicker, a chromium oxide single layer structure may be used.

In addition, the resin BM may be made of a material other than black as a pigment, and may be mixed with a material of each color to absorb light as a result.

Other materials may be used as long as the resin does not adversely affect the liquid crystal and is easy to form.

In the above description, the black matrix in the display area has been described. However, the reflected light that adversely affects the contrast of the liquid crystal is not limited to that from the black matrix. That is, a black frame having a width of about 2 to 5 mm is generally formed around the display area of the liquid crystal display element by the light shielding layer in many cases. However, conventionally, the black frame has been formed of the same material as the black matrix for the convenience of the manufacturing process and the like, so that the back surface of the black frame also has a metallic luster. For this reason, light leakage also occurs around the black frame. Therefore, light leakage around the display can be reduced by making the back surface of the black frame a material that absorbs light.

The liquid crystal to be used is not limited to the OCB mode liquid crystal. That is, any liquid crystal in a mode of displaying using birefringence or a display element using such a liquid crystal may be used. For example, an ASV (advanced super buoy) mode rubbed in a parallel direction may be used.

In this embodiment, a transmissive display element has been described, but a reflective display element may be used. In this case, the problematic reflected light passes through the liquid crystal layer four times.

In the present invention, since the influence of subtle reflected light is a problem, the higher the contrast, the more the problem. A display element having a contrast of 100 or more is effective, and a contrast of 200 or more has a clear effect. Although the effect was observed with the STN-type display element, the effect was not so great because the STN-type liquid crystal element basically has low contrast.

(Second Embodiment) This embodiment relates to a measure for preventing reflection on the array substrate side.

In the above embodiment, the back surface of the black matrix is made of a light absorbing material as a measure for preventing reflection from the upper substrate. However, an ITO transparent electrode is formed on the upper substrate, and both the liquid crystal-ITO interface and the ITO-substrate interface will be described in detail in a later embodiment. While reflection occurs. Therefore, even if the resin BM is used for the black matrix portion or the like of the upper substrate, it is not possible to completely eliminate the reflection of light from the upper substrate to the lower substrate. Then, when the reflected light from the liquid crystal-ITO interface or the like is reflected again on the lower substrate, the reflected light causes a decrease in contrast due to the above-described reason, although the degree of the difference may be different.

By the way, the present invention is not limited to this embodiment, but in a liquid crystal display device, the lower substrate is generally an active matrix substrate. Therefore, a large number of TFT transistors, metal wirings, and the like are considerably large on the substrate relative to the display portion. They are formed so as to occupy a certain area, and they reflect this reflected light upward again for the reasons described above. (Note that, for reference, the wiring is larger than the active element in terms of area.) In addition, light that has entered from the upper substrate side is also reflected to the upper substrate side.

Therefore, in this embodiment, as shown in FIG. 4, a resin layer in which a light-absorbing pigment is dispersed above the TFTs and wirings 108 of the lower substrate 107, the resin BM referred to in the present invention.
301 was formed. As a result, reflection of light to the upper part on the lower substrate was reduced, the contrast was improved, and a contrast 250 could be obtained.

In this embodiment, the light absorbing material may be a material other than the resin BM.

(Third Embodiment) In the present embodiment,
Only an ITO transparent electrode is formed on the upper substrate, and an array of TFTs, electrodes, and wirings and a color filter are formed on the lower substrate. FIG. 5 conceptually shows a main part of the liquid crystal display device of the present embodiment. As shown in the center of the figure, green (G) as a resin BM is provided on the lower substrate 107.
Was formed slightly larger than the pixel size. For this reason, this color filter has an overhang portion 1121 also on the array of the lower substrate and the metal wiring 108.

In the present embodiment, first, the upper substrate 11
Since only the transparent electrode 109 is formed on the substrate 1, the number of members contributing to reflection is small, the contrast can be further improved as compared with the second embodiment, and the contrast 300 can be obtained. .

Next, in the lower substrate, since the material is metal, reflection of the wiring becomes a problem in particular.
Although not all of the reflected light is absorbed, practically sufficient effects were obtained only by forming a green color filter on the metal wiring. That is, the color filter absorbs reflected light of a complementary color which affects the sensitivity of human eyes.

Further, in this embodiment, there is no need to separately form the resin BM, so that there is a merit of cost reduction.

Of course, as shown in FIG. 4, a resin BM that completely absorbs light may be formed above the active element and the wiring. Further, depending on the arrangement of the pixels and the like, a part of the resin BM may be used for a color filter of another color.

If the resin BM that completely absorbs light is formed, the manufacturing process is increased, but the reflected light is completely absorbed.

(Fourth Embodiment) This embodiment focuses on the angle of incidence of the reflected light, and therefore uses a condensing means.

In the above three embodiments, light reflected by the back surface of the black matrix and the array wiring is reduced. By the way, in a normal liquid crystal display device, the black matrix of the opposing substrate and the array wiring of the array substrate are in a direction orthogonal to the substrate surface, which is the direction in which the display surface is viewed when the user actually uses the completed liquid crystal display device. When viewed from above, they are designed to overlap exactly.
Therefore, most of the light incident on the back surface of the black matrix and the array wiring from the vertical direction is reflected on each other and eventually attenuated, so that the contrast is not significantly affected.

That is, the light which has an adverse effect on the contrast due to internal reflection is light which is obliquely incident on the substrate surface. Therefore, as shown in FIG. 6, the prism sheet 2 is disposed between the liquid crystal panel 113 and the light guide plate 101.
By arranging the light condensing means such as 10, it is possible to direct the backlight light as much as possible in the direction perpendicular to the substrate surface, that is, in the front direction, to reduce the light itself in oblique directions, and to reduce the decrease in contrast due to the reflection. It is what you can do. In (1) of this drawing, 210 is a prism sheet, and (2) is a diagram showing the function of the prism sheet.

(Fifth Embodiment) In this embodiment,
Similar to the previous embodiment, as a means for reducing light incident on the substrate surface from an oblique direction, as shown in FIG.
A condensing / reflecting means 211 for reflecting the backlight light toward the front direction is provided on the back (non-front) side of the light source.

In this way, the same effect as in the previous embodiment was obtained.

(Sixth Embodiment) This embodiment is intended to prevent reflection between layers having different refractive indexes.

In the first to third embodiments, the metallic glossy portion on the side facing the liquid crystal layer is covered with the resin BM to prevent a reduction in contrast due to light reflected from the metal surface. However, based on the recent demand for a high contrast ratio, this measure alone is not always sufficient to satisfy the high demands of users. Thus, in the present embodiment, reflection between surfaces having different refractive indices is prevented particularly in a region through which light passes.

The refractive index of ITO used for the transparent electrode is about 1.9 to 2.0, and the refractive indexes of the substrate and the liquid crystal layer in contact therewith are about 1.5. By the way, generally, the amplitude reflectance = {(n ₁ −n ₂ ) / (n ₁ + n ₂ )}.
² (for example, published by Shokabo “Optics” by Kozo Ishiguro), the values of n ₁ and n ₂ are about 1.5 to ₁ and n ₁ and n ₂
Is large, the reflectance becomes large. For this reason, ITO
Approx. 2% at interface between liquid crystal and interface between ITO and substrate
Reflection occurs. Also in this case, similarly to the above-described embodiment, the reflected light passes through the liquid crystal layer three times to lower the contrast. Moreover, in this case, the contact area between the ITO and the liquid crystal layer or the substrate, that is, the area occupied by the pixel portion with respect to the display surface is extremely large, so that the contribution to the reduction in contrast is important.

FIG. 8 conceptually shows a main part of the liquid crystal display device of the present embodiment. In this liquid crystal display device, upper and lower substrates 1
Regarding the ITO layers 109 of both 07 and 111, ITO-
An acrylic resin layer having an intermediate refractive index of 1.7 is applied to the liquid crystal interface and the ITO-substrate interface, and is hardened to reduce unevenness on the array substrate.
20 is inserted. As a result, the reflectance at the ITO interface was reduced, the contrast was further improved, and a contrast of 400 was achieved.

Hereinafter, this will be described. For example, if the incident light is 1
When it is set to 00%, it is particularly effective to make the intensity of the reflected light finally out of the panel 0.03% or less. By the way, for example, when the reflection of the BM or array wiring on both surfaces is completely set to 0 and the film reflection is reduced to a negligible level, only the ITO reflection becomes apparent. And the reflectance is 4% * 4% = 0.16%. Here, since the retardation of the reflected light is excessive by 120 nm, the transmittance in the black state is 10%. The total reflected light intensity at this time is 0.0% when the incident light is 100%.
Assume that it was 16%. Actually, this reflects the reflection of the TFT wiring and the reflection of the back surface of the BM. For this reason, the conventional OCB panel reached 0.05%.

However, by combining this embodiment with each of the other embodiments and reducing it to 0.03% or less, the same level of contrast as TN can be realized. Further, it is possible to reduce the content to 0.02% or less by carefully selecting various materials and the like, thereby achieving higher contrast.

In the present embodiment, the antireflection treatment is performed on both the upper and lower sides of the ITO transparent electrode. However, it is needless to say that a corresponding effect is produced only on the upper side or the lower side.

In place of the acrylic resin, an organic conductive film having a refractive index of about 1.7 may be used. As a result, the electrical resistance of the ITO film can be further reduced.

(Seventh Embodiment) This embodiment relates to a countermeasure against interface reflection in a retardation film.

Although the retardation film has a two-layer structure in the liquid crystal display device of the present embodiment, light reflection occurs at this interface. In particular, since a film in which discotic liquid crystals are hybrid-aligned is formed on a base film having a refractive index of 1.5, the refractive indexes of the upper surface and the lower surface are different due to the difference in the arrangement of liquid crystal molecules.

According to the study of the present inventor, the refractive index of the surface where the discotic liquid crystal is horizontally aligned is 1.7 to 1.7.
It was about 2.0, and the interface between this surface and the base film or glass surface reflected light at a high rate. Therefore, the reflection at the interface was reduced by using an adhesive layer having a refractive index of 1.6 between these interfaces or by providing an adhesive layer having a refractive index of 1.6 to bond the two films. This situation is shown in FIG.
Shown in

In the figure, reference numeral 104 denotes a polarizing plate. 1
Numeral 061 denotes a film in which a discotic liquid crystal having a refractive index of 1.7 is horizontally aligned. 230 is an adhesive layer having a refractive index of 1.6. Reference numeral 1062 denotes a base film having a refractive index of 1.5. 1063 is a film in which discotic liquid crystal having a refractive index of 1.6 is hybrid-aligned. 111 is an upper substrate glass.

At this time, the reflectivity at the interface could be reduced to 0.2%. In the OCB mode liquid crystal display device, the reflectance needs to be 1% or less in order to improve the contrast, but it can be said that the reflectance is sufficient.

(Eighth Embodiment) In the present embodiment, an antireflection treatment is performed on the interface between the outermost polarizing plate of the liquid crystal display element and air. For the above-described reason, light is reflected outside the polarizing plate as it is, that is, when the antireflection treatment is not performed, based on the difference in the refractive index between air and the polarizing plate. By the way, at this time, there is little problem with light in the vertical direction. However, the light in the oblique direction does not completely disappear because the intersections of the polarizing plates are different from those at the front. As a result, internally reflected light having different retardations is generated.
Since the internally reflected light has a bluish tint, it looks bluish when viewed from an oblique direction during black display.

Therefore, in the liquid crystal display device of this embodiment,
An anti-reflection treatment was performed on the polarizing plate surface, thereby reducing internally reflected light with respect to oblique light. The antireflection film is shown at 221 in FIG. As a result, coloring in observing from an oblique direction in black display was also eliminated.

(Ninth Embodiment) This embodiment relates to a reflection type liquid crystal display device. FIG. 10 shows a cross-sectional structure of the liquid crystal display element of the present embodiment. In this figure, 10
Reference numeral 91 denotes a reflective lower electrode film. However, the liquid crystal was of a hybrid orientation in which one side was horizontal and one side was vertical. Generally, it has a structure called ROCB.

In this embodiment, the black matrix on the image side of the upper substrate is entirely made of resin BM200 made of a light absorbing material.

The upper portion may of course be an array substrate.

Further, a color filter may not be provided.

(Tenth Embodiment) This embodiment is directed to
Although it depends on the definition of the substrate, it relates to the case of one substrate.

In recent years, as part of the rationalization of manufacturing, as a means of reducing the weight of a product, a mixed liquid layer of a liquid crystal forming material and a transparent resin film forming material is formed on a substrate on which TFTs and wirings are formed in advance, and irradiation of ultraviolet rays is performed. For example, a transparent resin film serving as a liquid crystal layer at the lower portion and an upper substrate at the upper portion is formed. This is shown in (1) to (3) of FIG. In (1), reference numeral 107 denotes a lower substrate;
Reference numeral 09 denotes a transparent electrode for lower pixels on the upper surface, and 108
Is an array of active elements and wirings. Further, an upper portion 301 is a substantially lattice-like light absorbing material film.
1071 is a side wall portion. Reference numeral 1141 denotes a mixture of a liquid crystal material and a transparent resin film material.

Then, the raw material mixture is separated by irradiating ultraviolet rays as shown in (2), a liquid crystal layer 114 is formed on the lower substrate side as shown in (3), and a transparent resin film 1111 is formed thereon. Are formed.

(4) shows a completed state, and 1091
Is an upper transparent electrode made of an organic conductive resin. 2201
Is the refractive index between the air and the organic conductive resin film (about 1.
An anti-reflection film and an insulating film made of a transparent resin having 3).

In this embodiment, it is needless to say that the separated transparent resin film may have conductivity, and an antireflection film and an insulating film may be formed on the upper surface.

(Eleventh Embodiment) The present invention relates to a liquid crystal logic element.

In recent years, as shown in FIG. 12, an optical logic element 42 has been developed which outputs the calculation result of incident light 40 as passing light 41. This requires a high contrast ratio when applied to an optical computer. Also in this case, a high contrast ratio was obtained by reducing the internal reflection in the element employing the OCB liquid crystal having high response by combining the techniques described in the above embodiments.

Although the present invention has been described based on some embodiments thereof, the present invention reduces various interface reflections and the like to thereby provide an OCB type liquid crystal having a very excellent contrast ratio. A display device is provided. For this reason, reflected light may be reduced by combining some of the above embodiments.

In addition to the above, for example, the following is performed. 1) An organic conductive film is used instead of or in addition to the ITO film. 2) In the third embodiment, the peripheral projections of the three color filters are laminated to not only serve as a more effective black matrix, but also as a wall for blocking oblique light rays. 3) The arrangement of pixels of each color is delta or stripe.

[0091]

As can be seen from the above description, according to the present invention, it is possible to provide a liquid crystal display device having excellent display characteristics such as high contrast, especially when OCB mode liquid crystal is used.

[Brief description of the drawings]

FIG. 1 is a sectional structural view of a conventional OCB type liquid crystal display device.

FIG. 2 is a diagram showing a cross-sectional structure of the liquid crystal display element according to the first embodiment of the present invention.

FIG. 3 is a diagram for explaining a concept showing a cause of a decrease in contrast in a conventional OCB type liquid crystal display element.

FIG. 4 is a diagram showing a cross-sectional structure of a liquid crystal display device according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a cross-sectional structure of a liquid crystal display device according to a third embodiment of the present invention.

FIG. 6 is a diagram showing a cross-sectional structure of a liquid crystal display device according to a fourth embodiment of the present invention.

FIG. 7 is a diagram showing a cross-sectional structure of a liquid crystal display device according to a fifth embodiment of the present invention.

FIG. 8 is a diagram showing a cross-sectional structure of a liquid crystal display device according to sixth and eighth embodiments of the present invention.

FIG. 9 is a diagram showing an adhesive layer and an interfacial antireflection film between two retardation films according to a seventh embodiment of the present invention.

FIG. 10 is a diagram showing a cross-sectional structure of a liquid crystal display device according to a ninth embodiment of the present invention.

FIG. 11 is a diagram showing a state of manufacturing a liquid crystal display device according to a tenth embodiment of the present invention and a cross section of a finished product;

FIG. 12 is a system configuration diagram of a liquid crystal display device according to an eleventh embodiment of the present invention.

[Explanation of symbols]

REFERENCE SIGNS LIST 101 light guide plate 102 side light 103 backlight 104 polarizing plate 105 biaxially stretched optical compensation film 106 hybrid discotic optical compensation film 107 lower substrate 108 TFT, wiring 109 transparent electrode 1091 reflective electrode 110 resin black matrix 111 upper substrate 1111 upper transparent Resin film / substrate 112 Color filter 1121 Color filter overhang 113 Liquid crystal panel (transmission type) 1131 Liquid crystal panel (reflection type) 114 Liquid crystal 1141 Liquid crystal and resin film raw material 200 Resin black matrix 201 Chromium 202 Chromium oxide 210 Prism sheet 211 Collection Light reflection means 220 Antireflection layer 2201 Antireflection film 221 Antireflection film (air, polarizing plate) 230 Adhesive layer (film) 301 Light absorbing material layer, band 42 Optical logic Child

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) G02F 1/139 G02F 1/139 (72) Inventor Masaichi Ishihara 1006 Kazuma Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Inside (72) Inventor Katsuharu Hattori 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Yoshiki Tanaka 1006 Okadoma Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. 2H049 BA02 BA06 BB65 BC22 2H088 HA02 HA08 HA12 HA14 HA15 HA21 HA28 JA04 KA07 MA02 MA07 2H091 FA02Y FA08Y FA11Y FA14Y FA34Y FA35Y FA37Y FA41Z HA05 KA02 LA17 LA19

Claims (24)

[Claims] 1. A liquid crystal display device in which a liquid crystal in a mode in which display is performed by controlling the amount of birefringence is held on a substrate portion, wherein the liquid crystal display device has reflection reducing means for reducing reflection of each portion inside the liquid crystal display device. Characteristic liquid crystal display element. 2. A liquid crystal display device in which liquid crystal of a mode in which display is performed by controlling the amount of birefringence is held on a substrate portion, wherein at least a portion of at least one of the light non-passing portions of the substrate or the two substrates is provided. A liquid crystal display device, characterized in that a light-shielding portion is formed on the liquid crystal layer side as a light absorber. 3. A liquid crystal display device in which a liquid crystal of a mode in which display is performed by controlling the amount of birefringence is held on a substrate portion, wherein at least a part of at least a portion of a liquid crystal layer formed on a black matrix portion on the substrate is light. A liquid crystal display device having a light-shielding portion as an absorber. 4. A liquid crystal display device in which a liquid crystal of a mode in which display is performed by controlling the amount of birefringence is held on a substrate portion, wherein at least a part of an active element on an active matrix substrate or at least a part of wiring has a light absorbing portion. A liquid crystal display device comprising: 5. A liquid crystal display device in which a liquid crystal of a mode for performing display by controlling a birefringence amount is held between two substrates, wherein a light absorbing portion is provided at least partially on both of the two substrates. A liquid crystal display element comprising: 6. A liquid crystal display device in which liquid crystal of a mode in which display is controlled by controlling the amount of birefringence is held in a substrate portion, wherein a light absorbing portion is provided in at least a part of an active element on an active matrix substrate and at least a part of wiring. The liquid crystal display device according to claim 3, wherein: 7. The liquid crystal display device according to claim 1, wherein the light shielding portion is a light absorbing light shielding portion made of a light absorbing material. 8. The liquid crystal display element according to claim 7, wherein the light absorbing material is a light absorbing portion made of a resin in which the light absorbing material is dispersed and made of a resin. 9. A liquid crystal display device in which a liquid crystal of a mode in which display is performed by controlling a birefringence amount is held in a substrate portion, wherein light absorption formed in at least a part of an active element on an active matrix substrate and at least a part of wiring is provided. And a color filter. 10. A liquid crystal display device in which a liquid crystal of a mode in which display is performed by controlling the amount of birefringence is held on a substrate portion, wherein at least one color filter is formed on an active element on an active matrix substrate or on a wiring portion. A liquid crystal display device characterized in that it is a color filter formed at least in part. 11. The color filter according to claim 7, wherein the color filter of at least one color is a color filter formed on at least a part of an active element on an active matrix substrate or a wiring portion. Item 10. A liquid crystal display device according to item 8. 12. A liquid crystal display device in which liquid crystal of a mode in which display is performed by controlling the amount of birefringence is held on a substrate portion, wherein at least one of the transparent electrodes has an antireflection portion on the surface thereof. Characteristic liquid crystal display element. 13. A liquid crystal display device in which liquid crystal of a mode in which display is performed by controlling the amount of birefringence is held on a substrate portion, wherein at least one side of the substrate or two substrates is subjected to an antireflection treatment at an interface. A liquid crystal display device comprising at least one retardation film. 14. A liquid crystal display device in which a liquid crystal of a mode in which display is performed by controlling the amount of birefringence is held on a substrate portion, wherein at least one of the substrate and the two substrates is subjected to an antireflection treatment at an interface. 13. The liquid crystal display device according to claim 1, comprising at least one retardation film. 15. A retardation film having an interface reflectance of 1% or less on at least one of a substrate and two substrates in a liquid crystal display element in which a liquid crystal in a mode of performing display by controlling a birefringence amount is held on a substrate portion. A liquid crystal display device comprising at least one sheet of 16. The liquid crystal display device according to claim 1, wherein the retardation film is a retardation film having a non-zero retardation value at the front. 17. The method according to claim 1, wherein the retardation film has a plurality of laminated structures, and at least one of the laminated portions has an antireflection processing portion. The liquid crystal display element as described in the above. 18. The liquid crystal display device according to claim 1, further comprising an antireflection processing unit at least at one air layer interface of the liquid crystal display device unit. 19. The liquid crystal display device according to claim 1, further comprising a light condensing means for condensing light in a front direction. 20. The liquid crystal display device according to claim 1, wherein the light guide plate has a light condensing means for condensing light in a front direction. 21. The liquid crystal display device according to claim 1, wherein the liquid crystal is a liquid crystal having a non-zero retardation when performing black display. 22. The liquid crystal display device according to claim 1, wherein the liquid crystal is an OCB type display mode liquid crystal. 23. The liquid crystal display device according to claim 1, wherein a contrast value is 100 or more. 24. The liquid crystal display according to claim 1, wherein light emitted through reflection inside the liquid crystal display element is 0.03% or less of total incident light. element.