JPH07294896A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To make a reflection display bright and to make a transmission display high in contrast by forming a single-layered film, which has both diffuse reflection and light shielding properties to light between pixels of a liquid crystal display panel. CONSTITUTION:The liquid crystal display device 17 operates in super-twisted nematic(STN) mode and is constituted by laminating an upper polarizing plate 12, a phase difference plate 13, a liquid crystal display panel 11, a lower polarizing plate 14, and a translucent reflecting plate 15 in order and arranging a back light 16 below the translucent reflecting plate 15. Further, the reflecting films 2 which are hatched are formed by coating the upper transparent substrate 1 with resin wherein pigment is dispersed. Namely, the reflecting films 2 are positioned between electrodes of transparent electrodes 4 formed in stripes and correspond to the parts between the upper transparent electrodes 8. Thus, the reflecting films 2 are formed on the rear surface of the upper transparent substrate 1 in a grid shape.

Description

Detailed Description of the Invention

[0001]

The present invention relates to an OA device or PD
The present invention relates to a liquid crystal display device mounted on a portable device such as A.

[0002]

2. Description of the Related Art Conventionally, there is a method of providing a light-shielding film between pixels which are non-pixel portions in order to increase the contrast ratio of the screen of a liquid crystal display device or the like and make the screen easy to see. Specific examples thereof are disclosed in, for example, JP-A-5-264984 and JP-A-6-11613.

For example, the black mask 72 of the negative display type liquid crystal display cell 78 shown in FIG. 13 is formed in a desired pattern by offset printing a paint containing a light absorbing material on a transparent substrate 71. As the light absorbing material, bismuth sulfide, carbon black, titanium black, graphite and the like, which are black materials having low diffuse reflectance, are used. The transparent electrode 73 is formed by depositing and etching ITO (indium tin oxide) after forming the black mask 72. In addition, the liquid crystal 77 is the seal film 7.
4 and the glass plate 76 on which the transparent electrode 75 is formed are provided and then injected and sealed. The above coating material is also used for the seal film 74, but a glass spacer is added and mixed. The light 79 is provided below the transparent substrate 71.

The light-shielding film thus provided between the pixels is
Light leakage from adjacent pixels and reflection of external light can be suppressed, which is useful for increasing the contrast ratio of the display screen.

On the other hand, a conventional technique of providing a metal light-shielding film and a light-scattering film between pixels is disclosed in JP-A-6-18714. According to this disclosure, a light-scattering film is formed by applying a dispersion liquid in which zirconium oxide fine particles are dispersed in a photosensitive binder onto a transparent substrate and developing the dispersion liquid. The metal light-shielding film is formed by sputtering a Cr film on the light-scattering film. As a result, the light that enters from the viewer side of the display screen and is reflected by the metal light-shielding film is scattered by the light-scattering film, so that it is possible to suppress a decrease in the contrast ratio of the display screen due to the reflected light. However, the two-layer structure of the light scattering film and the metal light shielding film is adopted, and the light scattering film itself does not have both the functions of the reflection film and the light shielding film.

Further, in the conventional liquid crystal display panel for both reflective and transmissive display, no film such as a light shielding film or a reflective film is formed between pixels.

[0007]

However, in the conventional liquid crystal display device in which a light-shielding film such as a black mask is formed between pixels, a material having a small surface reflectance with respect to light such as a black pigment is used. It can only be used for type display. That is, when this type of liquid crystal display device is used for reflective display or for both reflective and transmissive display, there is a problem that the reflective display is dark and visibility is poor.

Further, in the conventional reflective / transmissive liquid crystal display device having no light-shielding film between pixels, when used in transmissive display, light leakage occurs between pixels during black display, resulting in sharp contrast. There is a problem that a low-contrast display is obtained.

An object of the present invention is to solve the above two problems at the same time, and to provide a liquid crystal display device which is bright in reflective display and has high contrast in transmissive display.

[0010]

In order to solve the above-mentioned problems, the liquid crystal display device according to the invention of claim 1 has a diffuse reflection property and a light blocking property for light between the pixels of the liquid crystal display panel. The feature is that a single layer film is formed.

In order to solve the above-mentioned problems, a liquid crystal display device according to a second aspect of the present invention has a diffuse reflectance of light of 50% or more in the visible light region and a transmittance of the film according to the first aspect. Is 5% or less in the visible light range, the film has a binder (for example, a photocurable resin) containing a white pigment (for example, titanium oxide, zinc oxide, antimony oxide) or a pearl pigment having a particle diameter of 1 μm or less. It is characterized in that it is formed of a material dispersed in a ratio of 50 to 90% by weight.

In order to solve the above-mentioned problems, a liquid crystal display device according to a third aspect of the present invention has a film according to the first aspect, in which one of the transparent substrates facing each other with a liquid crystal layer interposed therebetween is provided between the pixels. It is characterized in that it is formed in a pattern corresponding to the shape.

In order to solve the above-mentioned problems, a liquid crystal display device according to a fourth aspect of the present invention has two transparent substrates facing each other with a liquid crystal layer interposed therebetween, and the facing surfaces of the respective transparent substrates are orthogonal to each other. And a transparent electrode formed in a stripe shape in each direction, wherein the film according to claim 1 is formed on a facing surface of each transparent substrate and in a gap portion between the respective transparent electrodes. It has a feature.

In a liquid crystal display device according to a fifth aspect of the present invention, in order to solve the above problems, the film according to the fourth aspect has a specific resistance (for example, 1 × 1) of a liquid crystal material forming the liquid crystal layer.
Material with a specific resistance greater than 0 ⁸ Ωcm) (eg,
It is characterized by being formed of a photocurable resin.

[0015]

According to the structure of the first aspect, firstly, by providing the diffuse reflective film between the pixels, the light incident on the liquid crystal display device from the observer side during the reflective display is a diffuse reflective film. Since it is also diffusely reflected, the reflective display can be made brighter. Secondly, since the diffuse reflective film also has a light-shielding property, light leakage between pixels is suppressed when displaying black by transmissive display using a backlight, for example, and high contrast display with sharpness is achieved. Can be obtained. Further, since it is sufficient to provide a single layer film between the pixels, the liquid crystal display device can be easily manufactured.

As described above, according to the structure of the first aspect, it is possible to provide a liquid crystal display device which is bright in reflective display and high in contrast in transmissive display, which is suitable for both reflective and transmissive types.

According to the second aspect of the present invention, when the particle diameter of the white pigment or pearl pigment is 1 μm or less, the diffuse reflectance of the above film with respect to light can be 50% or more in the visible light range. As a result, the brightness of white display required for reflective display can be obtained, and display with good visibility can be obtained. However, the proportion of the pigment dispersed in the binder is 50
If it is less than 5% by weight, the visible light transmittance exceeds 5%, and it becomes impossible to sufficiently suppress light leakage from between pixels during black display by transmissive display. Also,
If it exceeds 90% by weight, it will not be sufficiently cured when a resin is used as a binder, making it difficult to form a film. Therefore, it is important to disperse a white pigment or pearl pigment having a particle diameter of 1 μm or less in the binder at a ratio of 50 to 90% by weight.

According to the structure of claim 3, by forming the film in a pattern corresponding to the shape between the pixels, the film can be formed without gaps between all pixels. At the time of display, light leakage between pixels can be sufficiently suppressed.

According to the structure of claim 4, since the gap between the transparent electrodes corresponds to the pixel, the above-mentioned film is formed in the gap between the respective transparent electrodes so that there is no gap between all the pixels. Since this film is formed, it is possible to sufficiently suppress light leakage from between pixels during black display by transmissive display.

According to the structure of claim 5, when the above-mentioned film is formed in the gap portion between the respective transparent electrodes, it is possible to prevent the leakage from occurring between the adjacent transparent electrodes. This is because if the above film is made of a material having a specific resistance smaller than that of the liquid crystal material, the current does not flow to the liquid crystal layer because the current flows to the side with the smaller resistance, and the current flows to the next transparent electrode through the film. Because it will leak.
Therefore, by forming the above film with a material having a specific resistance larger than that of the liquid crystal material, it is possible to prevent such a leak from occurring.

[0021]

【Example】

[Embodiment 1] The following will describe one embodiment of the present invention with reference to FIGS. 1 to 3.

As shown in FIG. 1, the liquid crystal display device 17 according to the first embodiment of the present invention operates in a super twisted nematic (STN) mode, and has an upper polarizing plate 1 described later.
2, retardation plate 13, liquid crystal display panel 11, lower polarizing plate 1
4 and the semi-transmissive reflection plate 15 are sequentially laminated, and the backlight 16 is arranged below the semi-transmission reflection plate 15.

The upper polarizing plate 12 has a single transmittance of 44.5%,
It is a neutral gray type polarizing plate having a polarization degree of 97.8%, and for example, F1225DUN manufactured by Nitto Denko Corporation can be used. The retardation plate 13 is the first retardation layer 1
3a and the second retardation layer 13b.
Each of the retardation layers 13a and 13b is made of a uniaxially stretched polymer film (for example, polycarbonate) and has a thickness of 50 μm.
A film having a thickness of about m has a retardation value of 430 nm.

The material of the upper transparent substrate 1 and the lower transparent substrate 9 may be glass or plastic. The reflection film 2 shown by hatching in FIG. 1 contains 50 to 90% by weight of pigment.
It is formed by applying the resin dispersed in the above ratio on the upper transparent substrate 1. As the pigment, a white pigment such as titanium oxide, zinc oxide or antimony oxide having a particle diameter of 1 μm or less, or a pearl pigment can be used. A photo-curable resin is used as the binder resin for dispersing the pigment. As a result, the reflective film 2 has a large diffuse reflectance and a light shielding property.

Here, the diffuse reflection means the diffuse reflection of light excluding specular reflection according to the law of reflection, and the diffuse reflectance means the ratio of the diffuse reflection light quantity to the incident light quantity. Further, the proportion of the pigment dispersed in the photocurable resin is 5
When it is less than 0% by weight, the visible light transmittance of the reflective film 2 is 5%.
If the amount exceeds 90% by weight, the light-curing resin will not be sufficiently cured.

Further, the reflection film 2 is formed between the electrodes of the upper transparent electrode 4 formed in a stripe shape, and the electrode of the lower transparent electrode 8 formed in a stripe shape orthogonal to the upper transparent electrode 4. It is formed so as to correspond to the space.
That is, as shown in FIG. 2, the reflective film 2 is formed on the back surface of the upper transparent substrate 1 in a grid pattern. However, the reflective film 2
It may be similarly formed on the surface of the lower transparent substrate 9 instead of the back surface of the upper transparent substrate 1. When the reflective film 2 is formed on the surface of the lower transparent substrate 9, the overcoat layer 3 is also formed on the lower transparent substrate 9 side.

The overcoat layer 3 is made of a thermosetting resin, and includes an insulating film between the reflective film 2 and the upper transparent electrode 4, a base film for providing flatness for forming the upper transparent electrode 4, and a liquid crystal layer 6. It is provided for the purpose of a protective film for preventing the reflective film 2 from being contaminated by ionic impurities. The alignment films 5 and 7 are made of an inorganic thin film formed by vapor-depositing SiO ₂ or the like or a polymer thin film subjected to a rubbing treatment, and are provided for the purpose of easily obtaining the necessary alignment of liquid crystal molecules.

The liquid crystal layer 6 has a twist angle of 24 for liquid crystal molecules.
0 °, the thickness of the liquid crystal layer was set to 6 μm, the refractive index anisotropy of liquid crystal molecules Δn = 0.140, and the elastic constant ratio K ₃₃ / K
A liquid crystal material with a chiral dopant added was used at ₁₁ = 1.7.

The lower polarizing plate 14 is, like the upper polarizing plate 12, a neutral gray type polarizing plate having a single transmittance of 44.5% and a polarization degree of 97.8%. For example, F1225DUN manufactured by Nitto Denko Corporation is used. Can be used. The semi-transmissive reflector 15 is an omnidirectional semi-transmissive reflector having a transmittance of 2.5%.

A liquid crystal display panel 1 having the above components
The manufacturing method of 1 is as follows.

First, the resin in which the above pigment is dispersed is applied onto the upper transparent substrate 1. After applying the resin in which the pigment is dispersed,
Irradiate light through a photomask. As a result, the portion of the photocurable resin that has been irradiated with light is cured, and the portion that has not been irradiated with light remains uncured, so the reflection film 2 is formed by removing the uncured portion.

Next, the upper transparent substrate 1 on which the reflective film 2 is formed
An overcoat layer 3 is laminated on the top using a thermosetting resin. Further, the stripe-shaped upper transparent electrode 4 is laminated by an existing method, for example, vapor deposition and etching of ITO (indium tin oxide), and then the alignment film 5 is sequentially laminated. Similarly, the lower transparent electrode 8 and the alignment film 7 are laminated also on the lower transparent substrate 9 facing each other. Finally, the upper and lower substrates are bonded together with the sealant 10 via the in-cell spacer, and a liquid crystal material is injected to form the liquid crystal layer 6. The liquid crystal display panel 11 is manufactured by the above procedure.

FIG. 3 shows an arrangement relationship of each component of the liquid crystal display device 17. Of the arrows shown in FIG. 3, arrow P
Reference numeral 1 represents the alignment axis of liquid crystal molecules on the surface of the alignment film 5 located on the upper transparent substrate 1 side, and arrow P2 is the lower transparent substrate 9
The alignment axis of liquid crystal molecules on the surface of the alignment film 7 located on the side is represented by an arrow P3, the absorption axis of the upper polarizing plate 12 is shown, the arrow P4 is the absorption axis of the lower polarizing plate 14, and the arrow P5 is the first. Represents the slow axis of the retardation layer 13a, and the arrow P6 represents the slow axis of the second retardation layer 13b.

The angle α1 is the angle formed by the arrows P1 and P3, the angle β1 is the angle formed by the arrows P2 and P4, the angle θ1 is the angle formed by the arrows P1 and P6, and the angle γ1 is the arrow P1. The angle formed by the arrow P5 and the angle φ1 represent the twist angle of the liquid crystal molecule. In the first embodiment, α1 = 55 °, β1 = 50 °, θ1 = 80 °, γ1
Each constituent member was set and arranged so that the angle was 125 °. Further, the twist angle φ1 of the liquid crystal molecules was set to 240 °.

[Second Embodiment] The following will describe another embodiment of the present invention with reference to FIGS. 4 and 5.

As shown in FIG. 4, the liquid crystal display device 33 according to the second embodiment of the present invention operates in the super twisted nematic (STN) mode. The upper transparent substrate 18, the liquid crystal layer 22, and the alignment films 20 and 2 provided in the liquid crystal display device 33.
3, the lower transparent substrate 25, the upper polarizing plate 28, the retardation plate 29 including the first retardation layer 29a and the second retardation layer 29b, the lower polarizing plate 30, and the semi-transmissive reflection plate 31 are implemented. Upper transparent substrate 1, liquid crystal layer 6, alignment film 5 in Example 1
7, a lower transparent substrate 9, an upper polarizing plate 12, a retardation plate 1 including a first retardation layer 13a and a second retardation layer 13b.
3, the lower polarizing plate 14 and the semi-transmissive reflection plate 15 may have the same configuration.

The manufacturing method of the liquid crystal display panel 27 is as follows.

First, a resin in which a pigment is dispersed is applied onto the upper transparent substrate 18. However, in this embodiment, the reflection film 21 shown by hatching in FIG. 4 is provided between the adjacent upper transparent electrodes 19 and between the adjacent lower transparent electrodes 24.
Therefore, in order to avoid the occurrence of leakage between the patterns of the transparent electrode, the resin as the binder for dispersing the pigment,
A material having a specific resistance of 1 × 10 ⁸ Ωcm, which is a general value of liquid crystal materials, is used. As such a resin, a photocurable resin such as Photorec A704 may be used.
The pigment is as described in Example 1.

After applying the resin in which the pigment is dispersed, light is irradiated through a photomask. As a result, the portion of the photocurable resin that has been irradiated with light is cured, and the portion that has not been irradiated with light remains uncured. Thus, the reflection film 21 is formed by removing the uncured portion. The reflective film 21 is formed in a stripe shape at a position to fill the gap between the upper transparent electrodes 19 to be formed next.

Further, as shown in FIG. 5, the upper transparent substrate 1
The reflective film 21 is formed on the lower transparent substrate 25 in the same manner as the reflective film 21 is formed on the lower transparent substrate 25. However, the reflective film 21 on the lower transparent substrate 25 is formed in a stripe shape at a position to fill the gap between the lower transparent electrodes 24 that are subsequently formed. As a result, the reflective film 21 is formed on each transparent substrate 1
8 and 25 are provided so as to extend in a direction intersecting with each other.

Next, a transparent conductive film made of, for example, ITO (Indium Tin Oxide) is formed on the reflective film 21 by vapor deposition, a photoresist is further applied, and then exposure, development and etching processes are performed through a photomask. Then, the transparent electrode 19 is formed. Then, the alignment film 20 is formed by a conventional method.
To form.

Finally, the upper and lower substrates are bonded together by the sealant 26 via the in-cell spacer, and the liquid crystal material added with the chiral dopant is injected to form the liquid crystal layer 22. The liquid crystal display panel 27 is manufactured by the above procedure.

The liquid crystal layer 22 has a twist angle 24 of liquid crystal molecules.
The liquid crystal layer thickness was set to 0 ° and the liquid crystal layer thickness was set to 6 μm, the refractive index anisotropy of liquid crystal molecules was Δn = 0.140, and the elastic constant ratio was K ₃₃ / K ₁₁ = 1.7.
The liquid crystal material of was used.

The arrangement relation of each element constituting the liquid crystal display panel 27 is set in the same manner as the arrangement relation described in the first embodiment based on FIG.

[Comparative Example 1] A liquid crystal display device 48 as a comparative example 1 was manufactured in order to compare the display characteristics of the screen with the liquid crystal display devices 17 and 33 having the configurations of the first and second embodiments.

As shown in FIG. 6, the liquid crystal display device 48 is
The sealing material 26, the liquid crystal display panel 27, the upper polarizing plate 28, and the first retardation layer 2 in the liquid crystal display device 33 of the second embodiment.
Retardation plate 2 including 9a and the second retardation layer 29b
9, the lower polarizing plate 30, the semi-transmissive reflecting plate 31, and the backlight 32 are respectively provided with a sealing material 41, a liquid crystal display panel 42, an upper polarizing plate 43, a first retardation layer 44a and a second retardation layer 44b. The phase difference plate 44, the lower polarizing plate 45, the semi-transmissive reflection plate 46, and the backlight 47 are replaced. In addition, the liquid crystal display panel 27
Upper transparent substrate 18, upper transparent electrode 19, liquid crystal layer 22,
Similarly, the alignment films 20 and 23, the lower transparent electrode 24, and the lower transparent substrate 25 also include the upper transparent substrate 34 and the upper transparent electrode 3.
5, liquid crystal layer 37, alignment films 36 and 38, lower transparent electrode 3
9 and the lower transparent substrate 40.

The difference between the liquid crystal display device 48 and the liquid crystal display device 33 is that no reflective film is provided between the patterns of the upper transparent electrode 35 and between the patterns of the lower transparent electrode 39.

The arrangement relation of each element constituting the liquid crystal display panel 42 is set in the same manner as the arrangement relation described in the first embodiment based on FIG.

[Comparative Example 2] A liquid crystal display device 64 as another comparative example 2 was manufactured in order to compare the display characteristics of the liquid crystal display devices 17 and 33 having the structures of Examples 1 and 2 and the screen. .

As shown in FIG. 7, the liquid crystal display device 64 is
The sealing material 26, the liquid crystal display panel 27, the upper polarizing plate 28, and the first retardation layer 2 in the liquid crystal display device 33 of the second embodiment.
Retardation plate 2 including 9a and the second retardation layer 29b
9, the lower polarizing plate 30, the semi-transmissive reflecting plate 31, and the backlight 32 are respectively provided with a sealing material 57, a liquid crystal display panel 58, an upper polarizing plate 59, a first retardation layer 60a and a second retardation layer 60b. The phase difference plate 60 is composed of a lower polarizing plate 61, a semi-transmissive reflection plate 62, and a backlight 63. In addition, the liquid crystal display panel 27
Upper transparent substrate 18, upper transparent electrode 19, liquid crystal layer 22,
Similarly, the alignment films 20 and 23, the lower transparent electrode 24, and the lower transparent substrate 25 also include the upper transparent substrate 49 and the upper transparent electrode 5.
0, liquid crystal layer 53, alignment films 51 and 54, lower transparent electrode 5
5 and the lower transparent substrate 56.

The difference between the liquid crystal display device 64 and the liquid crystal display device 33 is that the light-shielding film 5 having a low diffuse reflectance is provided between the patterns of the upper transparent electrode 50 and between the patterns of the lower transparent electrode 55.
2 (shown by hatching in FIG. 7). The light shielding film 52 is formed of carbon black or the like.

The arrangement relation of each element constituting the liquid crystal display panel 58 is set in the same manner as the arrangement relation described in the first embodiment based on FIG.

[Comparison Results] FIG. 8 shows the reflective film 2 of the liquid crystal display panel 11 of the first embodiment and the liquid crystal display panel 27 of the second embodiment.
9 shows the spectral characteristics of the diffuse reflectance in the visible light region of the reflective film 21 and the light shielding film 52 of the liquid crystal display panel 58 of Comparative Example 2. The diffuse reflectance measuring device is, for example, Minolta C
M1000 can be used. The measuring device includes a light source and a diffusing sphere having a diffuse reflection surface on the inner wall. The diffuse reflectance is obtained by irradiating the measurement sample with the light of the light source diffused and reflected in the diffusing sphere and receiving the light reflected by the surface of the measuring sample in the same diffusing sphere. At this time, 1 of the diffusion sphere
Calibrate by placing a standard white plate on the surface of the measurement sample that is open at the location. The diffuse reflectance of the measurement sample surface is calculated as a relative value when the reflectance of the standard white plate is set to about 100%.

Both the reflection films 2 and 21 of Examples 1 and 2 exhibit the same spectral characteristics shown by the curve 65, and the diffuse reflectance in the visible light region is 50% or more. Further, the light-shielding film 52 of Comparative Example 2 exhibited the spectral characteristic indicated by the curve 66, and the diffuse reflectance in the visible light region was a low value of 50% or less.

FIG. 9 shows the reflective film 2 of the liquid crystal display panel 11 of the first embodiment and the reflective film 2 of the liquid crystal display panel 27 of the second embodiment.
1 and the light shielding film 52 of the liquid crystal display panel 58 of Comparative Example 2
The spectral characteristic of the transmittance in the visible light region of is shown. In each of Example 1, Example 2, and Comparative Example 2, the same spectral characteristic indicated by the curve 67 is exhibited, and the transmittance in the visible light region is 5 each.
% Or less.

Table 1 below shows the contrast ratios of the liquid crystal display devices of Example 1, Example 2, Comparative Example 1, and Comparative Example 2 and the brightness L * in the reflective display when no voltage is applied. During the reflective display, the backlight 16, 32.4
Turn off the 7/63.

[0057]

[Table 1]

In Table 1, the contrast ratio was measured under the following conditions.

Contrast measurement condition: drive 1/240 DUTY, 1/13 Bias environment temperature 25 ° C. measurement spot diameter 10 mmφ Further, the brightness L * is defined by CIE1976L * a * b * color system (JIS Z8729- (1980)). It was done.

FIG. 10 is a schematic diagram showing pixels and a state between the pixels in monochrome display of the liquid crystal display device 17 of the first embodiment and the liquid crystal display device 33 of the second embodiment.

As shown in Table 1, in the reflective display (backlight off), the contrast ratio is low in the black display because the pixels are bright, but in the white display, the diffusion of the reflective films 2.21 between the pixels is diffused. The high reflectance makes both pixels brighter.

In the transmissive display (lighting of the backlight), since the reflection films 2 and 21 between the pixels shield the light of the backlight, clear black and white display is obtained and the contrast ratio becomes high.

FIG. 11 shows a comparative example 1 in which a reflective film is not provided.
9 is a schematic diagram showing pixels and a state between the pixels in monochrome display of the liquid crystal display device 48 of FIG.

As shown in Table 1, in the reflective display (backlight off), the contrast ratio is low in the black display because the pixels are bright, but in the white display, both the pixels and the transflective plate 46 are arranged between the pixels. Is as bright as in Examples 1 and 2 because of its high diffuse reflectance.

FIG. 12 is a schematic view showing pixels and a state between the pixels in monochrome display of the liquid crystal display device 64 of Comparative Example 2 provided with the light shielding film 52.

As shown in Table 1, in the reflective display (backlight off), the contrast ratio is high because both the pixels and the pixels are dark in the black display, but in the white display, the light-shielding film 52 between the pixels is formed. Since it has a low diffuse reflectance and becomes dark (brightness L * = 39), it is not suitable for products.

In the transmissive display (lighting of the backlight), the light-shielding film 52 between the pixels shields the light of the backlight, so that clear black and white display is obtained and the contrast ratio becomes high.

As shown in Table 1, in both Example 1 and Example 2, Comparative Example 1 in which a reflective film was not provided between pixels
It can be seen that the contrast ratio in the transmissive display is 10 times higher than that in.

Further, in each of the first and second embodiments, as compared with the comparative example 2 in which the light shielding film 52 is provided between the pixels,
It can be seen that the brightness L * in the reflective display is large.

[0070]

The liquid crystal display device according to the invention of claim 1
As described above, the single-layer film having both the diffuse reflection property and the light shielding property for light is formed between the pixels of the liquid crystal display panel.

Therefore, since the above-mentioned film has the diffuse reflection property, the reflective display becomes bright, and because the above-mentioned film has the light-shielding property, the transmissive display has a high contrast. The liquid crystal display device suitable for both reflection and transmission can be provided.

As described above, in the liquid crystal display device according to the invention of claim 2, the diffuse reflectance of the film according to claim 1 with respect to light is 50% or more in the visible light region, and the transmittance is in the visible light region. Is 5% or less, the above film is formed of a material in which a white pigment or a pearl pigment having a particle diameter of 1 μm or less is dispersed in a binder at a ratio of 50 to 90% by weight.

Therefore, by setting the particle size of the white pigment or the pearl pigment to 1 μm or less, the diffuse reflectance of the above film with respect to the light can be 50% or more in the visible light region, and as a result, the reflection display can be achieved. Can be made brighter and a display with good visibility can be obtained. Further, by dispersing the white pigment or the pearl pigment in the binder at a ratio of 50% by weight or more, the above film can obtain a sufficient light-shielding property for suppressing light leakage from between pixels. further,
By dispersing the white pigment or the pearl pigment in the binder at a ratio of 90% by weight or less, the above film is easily cured even when a resin is used as the binder, and the film can be easily formed. Play.

In the liquid crystal display device according to the invention of claim 3, as described above, the film according to claim 1 corresponds to the shape between pixels on one of the transparent substrates facing each other with the liquid crystal layer interposed. It is a structure formed by a pattern.

Therefore, since the above-mentioned film is formed without gaps between all the pixels, it is possible to sufficiently suppress light leakage between the pixels during black display by transmissive display. Play.

In the liquid crystal display device according to a fourth aspect of the present invention, as described above, the two transparent substrates facing each other with the liquid crystal layer interposed, and the opposing surfaces of the respective transparent substrates are provided with stripes in directions orthogonal to each other. A transparent electrode formed in a strip shape, wherein the film according to claim 1 is on the facing surface of each transparent substrate,
This is a structure formed in the gap between the respective transparent electrodes.

Therefore, by forming the above film in the gap portion between the respective transparent electrodes, the above film can be formed without any gap between all the pixels, so that at the time of black display by transmissive display. Thus, there is an effect that light leakage from between pixels can be sufficiently suppressed.

As described above, in the liquid crystal display device according to the invention of claim 5, the film according to claim 4 is formed of a material having a specific resistance larger than that of the liquid crystal material forming the liquid crystal layer. It is a configured structure.

Therefore, when the above-mentioned film is formed in the gap between the transparent electrodes, it is possible to prevent the occurrence of leakage between the adjacent transparent electrodes.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing one structural example of a liquid crystal display device according to the present invention.

FIG. 2 is a perspective view showing a shape of a reflective film formed on a transparent substrate of the liquid crystal display device shown in FIG.

FIG. 3 is an explanatory diagram showing an arrangement relationship of each component of the liquid crystal display device shown in FIG.

FIG. 4 is a vertical cross-sectional view showing another configuration example of the liquid crystal display device according to the present invention.

5 is a perspective view showing a shape of reflective films formed on upper and lower transparent substrates of the liquid crystal display device shown in FIG.

FIG. 6 is a vertical cross-sectional view showing a configuration example of a liquid crystal display device as a first comparative example.

FIG. 7 is a vertical cross-sectional view showing one configuration example of a liquid crystal display device as a second comparative example.

FIG. 8 is a graph showing spectral characteristics of diffuse reflectance in the visible light region of the reflective film according to the present invention and the reflective film of the second comparative example.

FIG. 9 is a graph showing spectral characteristics of transmittance of a reflective film according to the present invention and a reflective film of a second comparative example in a visible light region.

10 is an explanatory diagram schematically showing a state between pixels in monochrome display of the liquid crystal display device shown in FIGS. 1 and 4. FIG.

11 is an explanatory diagram schematically showing a state between pixels in monochrome display of the liquid crystal display device shown in FIG.

FIG. 12 is an explanatory diagram schematically showing a state between pixels in monochrome display of the liquid crystal display device shown in FIG. 7.

FIG. 13 is a vertical cross-sectional view showing a configuration example of a conventional liquid crystal display device.

[Explanation of symbols]

 1 Upper Transparent Substrate 2 Reflective Film (Film) 4 Upper Transparent Electrode 6 Liquid Crystal Layer 8 Lower Transparent Electrode 9 Lower Transparent Substrate 17 Liquid Crystal Display 18 Upper Transparent Substrate 19 Upper Transparent Electrode 21 Reflective Film (Film) 22 Liquid Crystal Layer 24 Lower Side transparent electrode 25 Lower transparent substrate 33 Liquid crystal display device

Claims (5)

[Claims] 1. A liquid crystal display device comprising a liquid crystal display panel, in which a single-layer film having both light diffusive reflection property and light shielding property is formed between pixels of a liquid crystal display panel. 2. The above-mentioned film has a particle size of 1 μm or less so that the diffuse reflectance for light of the above film is 50% or more in the visible light region and the transmittance is 5% or less in the visible light region. White pigment or pearl pigment in the binder 50 to 90
The liquid crystal display device according to claim 1, wherein the liquid crystal display device is formed of a material dispersed in a weight percentage. 3. The liquid crystal display according to claim 1, wherein the film is formed on one of transparent substrates facing each other with a liquid crystal layer interposed therebetween in a pattern corresponding to a shape between pixels. apparatus. 4. A transparent substrate comprising two transparent substrates facing each other with a liquid crystal layer interposed therebetween, and transparent electrodes formed in stripes on the facing surfaces of the respective transparent substrates in directions orthogonal to each other. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is formed on a facing surface of each transparent substrate in a gap portion between the respective transparent electrodes. 5. The liquid crystal display device according to claim 4, wherein the film is formed of a material having a specific resistance larger than that of the liquid crystal material forming the liquid crystal layer.