JP3004534B2 - Liquid crystal display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an OA device or a 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 a screen of a liquid crystal display device or the like so that the screen is easy to see. Specific examples thereof are disclosed in, for example, JP-A-5-264983 and JP-A-6-11613.

For example, a black mask 72 of a 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, black materials having low diffuse reflectance such as bismuth sulfide, carbon black, titanium black, and graphite are used. The transparent electrode 73 is formed by depositing and etching ITO (indium tin oxide) after the formation of the black mask 72. In addition, the liquid crystal 77 is
4 and a glass plate 76 on which a transparent electrode 75 is formed, and then injected and sealed. The above-described paint is 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 provided between the pixels as described above
Light leakage from an adjacent pixel and reflection of external light can be suppressed, which is useful for increasing the contrast ratio of a display screen.

On the other hand, a prior art in which a metal light-shielding film and a light-scattering film are provided between pixels is disclosed in Japanese Patent Application Laid-Open No. 6-18714. According to this disclosure, a light scattering film is formed by applying a dispersion of zirconium oxide fine particles dispersed in a photosensitive binder on a transparent substrate and developing the dispersion. The metal light-shielding film is formed by sputtering a Cr film on the light scattering film. Accordingly, the light incident from the observer side of the display screen and reflected by the metal light-shielding film is scattered by the light scattering film, so that a decrease in the contrast ratio of the display screen due to the reflected light can be suppressed. However, a two-layer structure of a light scattering film and a metal light shielding film is adopted, and the light scattering film itself does not have both functions of the reflection film and the light shielding film.

Further, in a 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, the conventional liquid crystal display device having a light-shielding film such as a black mask formed between pixels uses a material having a small surface reflectivity to light, such as a black pigment, so that the liquid crystal display device has a low transmittance. Can only be used for type display only. 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 deteriorates.

Further, in a conventional reflective / transmissive liquid crystal display device having no light-shielding film between pixels, when used in transmissive display, light leakage occurs between the pixels during black display, resulting in sharpness. There is a problem that the display becomes a low-contrast display without any problem.

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 high in contrast in transmissive display.

[0010]

According to the invention of claim 1, there is provided an anti-skid device.
In order to solve the above-mentioned problems , the transmissive / transmissive liquid crystal display device is provided with a semi-transparent liquid crystal display on the side opposite to the display surface of the liquid crystal display panel.
A reflective / transmissive liquid crystal display device with a transflector
In the above, between the pixels of the liquid crystal display panel, a single-layer film having both a diffuse reflection property and light blocking property for light is formed ,
The film has a diffuse reflectance of 50 in the visible light region with respect to light.
% And the transmittance is 5% or less in the visible light range.
As described above, when the above film is made of a white pigment having a particle size of 1 μm or less (eg,
For example, titanium oxide, zinc oxide, antimony oxide) or
Add pearl pigment in a binder (for example, photocurable resin)
It is formed of a material dispersed in a ratio of 0 to 90% by weight.
It is characterized in that that.

[0011]

According to a second aspect of the present invention, there is provided a reflection / transmission type liquid crystal display device, wherein the film according to the first aspect is opposed to the liquid crystal display device via a liquid crystal layer. Is formed on one of the transparent substrates in a pattern corresponding to the shape between pixels.

According to a third aspect of the present invention, there is provided a reflection / transmission type liquid crystal display device, wherein two transparent substrates opposed to each other with a liquid crystal layer interposed therebetween are provided. A transparent electrode formed in a stripe shape in a direction orthogonal to each other on a facing surface of the transparent substrate, wherein the film according to claim 1 is on the facing surface of each transparent substrate and between the transparent electrodes. Is formed in the gap portion of the second.

According to a fourth aspect of the present invention, there is provided a reflection / transmission type liquid crystal display device for solving the above problems.
3. The film according to item 3 , wherein the film is formed of a material (for example, a photocurable resin) having a specific resistance greater than the specific resistance (for example, 1 × 10 ⁸ Ωcm) of the liquid crystal material forming the liquid crystal layer. Features.

[0015]

According to the first aspect of the present invention, a diffuse reflection film is first provided between the pixels, so that the light incident on the liquid crystal display device from the observer side during the reflective display is diffused and reflected. Is also diffusely reflected, so that the reflective display can be brightened. Second, since the diffusely reflective film also has a light-shielding property, for example, in the case of black display by transmissive display using a backlight, light leakage from between pixels is suppressed, and high-contrast display with sharpness is achieved. Can be obtained. Further, since only a single-layer film needs to be provided between pixels, fabrication of a liquid crystal display device is easy.

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

Further, if the particle diameter of the white pigment or pearl pigment is at 1μm or less, the diffuse reflectance for the light of the above film in the visible light region can be 50% or more. Thereby, the brightness of the white display required for the reflective display can be obtained, and the display with good visibility can be obtained. However, if the proportion of the pigment dispersed in the binder is less than 50% by weight, the visible light transmittance exceeds 5%, and it is sufficient to prevent light leakage from occurring between pixels during black display by transmission display. Can not be suppressed. On the other hand, if the content exceeds 90% by weight, the resin cannot be sufficiently cured when a resin is used as a binder, and it becomes difficult to form a film. Therefore, particle size 1
5 μm or less of white pigment or pearl pigment in binder
It is important to disperse at a rate of 0 to 90% by weight.

According to the second aspect of the present invention, since the film is formed in a pattern corresponding to the shape between pixels, the film is formed without gaps between all pixels. At the time of display, light leakage from between pixels can be sufficiently suppressed.

According to the third aspect of the present invention, since the gap between the transparent electrodes corresponds to between the pixels, the film is formed in the gap between the respective transparent electrodes so that there is no gap between all the pixels. Therefore, light leakage from between pixels can be sufficiently suppressed during black display by transmissive display.

According to the structure of the fourth aspect , when the film is formed in the gap between the transparent electrodes, it is possible to prevent a leak from occurring between the adjacent transparent electrodes. This is because if the above film is formed of a material having a specific resistance smaller than the specific resistance of the liquid crystal material, the current will flow to the lower resistance, so it will not flow to the liquid crystal layer, but to the next transparent electrode through the film. This is because it will leak.
Therefore, such a leak can be prevented by forming the above-mentioned film with a material having a specific resistance higher than the specific resistance of the liquid crystal material.

[0021]

【Example】

[Embodiment 1] An embodiment of the present invention will be described below with reference to FIGS.

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,
2, retardation plate 13, liquid crystal display panel 11, lower polarizing plate 1
4 and the transflective plate 15 are laminated in order, and a backlight 16 is arranged below the transflective plate 15.

The upper polarizer 12 has a single transmittance of 44.5%,
This is a neutral gray type polarizing plate having a polarization degree of 97.8%. For example, F1225DUN manufactured by Nitto Denko Corporation can be used. The phase difference plate 13 includes the first phase difference 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.
For a film of about m, the retardation value is 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.
Is formed by applying a resin dispersed in the ratio of As this pigment, a white pigment such as titanium oxide, zinc oxide, antimony oxide or the like having a particle size of 1 μm or less, or a pearl pigment can be used. As a resin as a binder for dispersing the pigment, a photocurable resin is used. Thereby, the reflection film 2 has a large diffuse reflectance and a light shielding property.

Here, "diffuse reflection" means the reflection of diffuse light excluding specular reflection in accordance with the law of reflection, and "diffuse reflectance" means the ratio of the amount of diffusely reflected light to the amount of incident light. Further, the ratio of the pigment dispersed in the photocurable resin is 5%.
When the content is less than 0% by weight, the visible light transmittance of the reflective film 2 is 5%.
When it exceeds 90%, the light-shielding property becomes insufficient. When it exceeds 90% by weight, the photocurable resin is not sufficiently cured.

Further, the reflection film 2 is provided 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 interval.
That is, as shown in FIG. 2, the reflection film 2 is formed on the back surface of the upper transparent substrate 1 in a lattice shape. However, the reflection film 2 is
It may be similarly formed on the surface of the lower transparent substrate 9 instead of the rear surface of the upper transparent substrate 1. When the reflection 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 is composed of 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 on which SiO ₂ or the like is deposited or a rubbed polymer thin film, and are provided for the purpose of easily obtaining necessary alignment of liquid crystal molecules.

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

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

Liquid crystal display panel 1 provided with the above components
The manufacturing method of No. 1 is as follows.

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

Next, the upper transparent substrate 1 on which the reflection film 2 is formed
The overcoat layer 3 is laminated thereon using a thermosetting resin. Furthermore, after the stripe-shaped upper transparent electrode 4 is laminated by an existing method, for example, vapor deposition and etching of ITO (indium tin oxide), the alignment film 5 is sequentially laminated. Similarly, the lower transparent electrode 8 and the alignment film 7 are laminated on the opposing lower transparent substrate 9. Finally, the upper and lower substrates are adhered to each other with the sealing material 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 according to the above procedure.

FIG. 3 shows an arrangement relationship of each component of the liquid crystal display device 17. Arrow P among the arrows shown in FIG.
Reference numeral 1 denotes an alignment axis of liquid crystal molecules on the surface of the alignment film 5 located on the upper transparent substrate 1 side, and an arrow P2 indicates a lower transparent substrate 9
The arrow P3 indicates the absorption axis of the upper polarizer 12, the arrow P4 indicates the absorption axis of the lower polarizer 14, and the arrow P5 indicates the first axis. Represents the slow axis of the phase difference layer 13a, and the arrow P6 represents the slow axis of the second phase difference layer 13b.

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

Embodiment 2 Another embodiment of the present invention will be described below 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 a super twisted nematic (STN) mode. The upper transparent substrate 18, the liquid crystal layer 22, and the alignment films 20 and 2 included in the liquid crystal display device 33.
3. The lower transparent substrate 25, the upper polarizer 28, the retarder 29 including the first retardation layer 29a and the second retardation layer 29b, the lower polarizer 30, and the transflector 31 Upper transparent substrate 1, liquid crystal layer 6, alignment film 5 in Example 1
7, a retardation plate 1 including a lower transparent substrate 9, an upper polarizing plate 12, a first retardation layer 13a, and a second retardation layer 13b.
3, the same configuration as the lower polarizer 14 and the transflector 15 may be used.

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

First, a resin in which a pigment is dispersed is applied on the upper transparent substrate 18. However, in this embodiment, the reflection films 21 indicated by hatching in FIG. 4 are 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, a resin as a binder for dispersing the pigment includes:
A material having a specific resistance of 1 × 10 ⁸ Ωcm, which is a general value of a liquid crystal material, is used. As such a resin, a photocurable resin such as Photolec 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 reflection film 21 is formed in a stripe shape at a position filling the gap between the upper transparent electrodes 19 to be formed next.

As shown in FIG. 5, the upper transparent substrate 1
The reflection film 21 is also formed on the lower transparent substrate 25 in the same manner as the formation of the reflection film 21 on the lower transparent substrate 25. However, the reflection film 21 on the lower transparent substrate 25 is formed in a stripe shape at a position filling the gap between the lower transparent electrodes 24 to be formed subsequently. Thereby, the reflection film 21 is formed on each transparent substrate 1.
8 and 25 so as to extend in a direction crossing 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, and after a photoresist is applied, exposure, development and etching are performed through a photomask. After that, the transparent electrode 19 is formed. Subsequently, the alignment film 20 is formed by a conventional method.
To form

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

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

The arrangement relation of the components constituting the liquid crystal display panel 27 is set in the same manner as the arrangement relation described in the first embodiment with reference to FIG.

[Comparative Example 1] A liquid crystal display device 48 as 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 structures of Examples 1 and 2.

As shown in FIG. 6, the liquid crystal display device 48
Sealing material 26, liquid crystal display panel 27, upper polarizing plate 28, first retardation layer 2 in liquid crystal display device 33 of Example 2
Retardation plate 2 including 9a and second retardation layer 29b
9, the lower polarizing plate 30, the transflective plate 31, and the backlight 32 are respectively formed by 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. , A lower polarizing plate 45, a transflective plate 46, and a backlight 47. Also, 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 a 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 the components constituting the liquid crystal display panel 42 is set in the same manner as the arrangement relation described in the first embodiment with reference to FIG.

Comparative Example 2 A liquid crystal display device 64 as another comparative example 2 was manufactured in order to compare the display characteristics between 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
Sealing material 26, liquid crystal display panel 27, upper polarizing plate 28, first retardation layer 2 in liquid crystal display device 33 of Example 2
Retardation plate 2 including 9a and second retardation layer 29b
9, the lower polarizer 30, the semi-transmissive reflector 31, and the backlight 32 are respectively replaced with a sealing material 57, a liquid crystal display panel 58, an upper polarizer 59, a first retardation layer 60a and a second retardation layer 60b. , A lower polarizing plate 61, a transflective plate 62, and a backlight 63. Also, 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 have 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 a 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 with reference to FIG.

[Comparison Results] FIG. 8 shows the reflection film 2 of the liquid crystal display panel 11 of the first embodiment and the liquid crystal display panel 27 of the second embodiment.
7 shows the spectral characteristics of the diffuse reflectance in the visible light region of the reflection film 21 of the liquid crystal display panel 58 of Comparative Example 2 and the light-shielding film 52 of the liquid crystal display panel 58 of Comparative Example 2. Examples of diffuse reflectance measuring instruments include Minolta C
M1000 can be used. The measurement device includes a diffusion sphere having a diffuse reflection surface on an inner wall and a light source. The measurement sample is irradiated with the light of the light source diffusely reflected in the diffusion sphere, and the light reflected on the measurement sample surface is received in the same diffusion sphere, thereby obtaining the diffuse reflectance. At this time, one of the diffusion spheres
Calibrate by placing a standard white plate on the measurement sample surface 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 about 100%.

The reflecting films 2 and 21 of the first and second embodiments both show the same spectral characteristic 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 reflection film 2 of the liquid crystal display panel 11 of the first embodiment and the reflection 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
2 shows the spectral characteristics of transmittance in the visible light range. Each of Example 1, Example 2, and Comparative Example 2 shows the same spectral characteristic shown by the curve 67, and the transmittance in the visible light region is 5
% 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 * when no voltage is applied in reflective display. During the reflective display, the backlight 16.32.4
7.63 was turned off.

[0057]

[Table 1]

In Table 1, the measurement of the contrast ratio was performed under the following conditions.

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

FIG. 10 is a schematic diagram showing the state of the pixels and the state between the pixels in the 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 reflective display (backlight extinguishing), the contrast ratio is low in black display because of the brightness between pixels, but in white display, the diffusion of the reflective films 2 and 21 between pixels is low. Since the reflectance is high, both the pixels and the pixels become bright.

In transmissive display (lighting of the backlight), the reflective films 2.21 between the pixels block the light of the backlight, so that a sharp black-and-white display is obtained and the contrast ratio is increased.

FIG. 11 shows Comparative Example 1 in which no reflective film was provided.
FIG. 6 is a schematic diagram showing a state between pixels and a state between pixels in a 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 black display because the pixels are bright, but in the white display, the transflective plate 46 is used for both pixels and pixels. Has a high diffuse reflectance, and is therefore as bright as Examples 1 and 2.

FIG. 12 is a schematic diagram showing the state between pixels in a black and white 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 extinguishing), the contrast ratio is high because both pixels are dark during black display, but the light-shielding film 52 between pixels during white display is dark. Since it is dark because of low diffuse reflectance (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 a sharp black-and-white display is obtained and the contrast ratio is increased.

As shown in Table 1, in both Examples 1 and 2, Comparative Example 1 in which a reflective film was not provided between pixels was used.
It can be seen that the contrast ratio in the transmissive display is 10 times as large as that in the case of FIG.

In each of the first and second embodiments, compared to 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 has increased.

[0070]

According to the first aspect of the present invention, the reflection / transmission type is used.
As described above, a liquid crystal display device of the type described above forms a single-layer film having both a diffuse reflection property and a light blocking property for light between pixels of a liquid crystal display panel, and the film has a diffuse reflectance for light.
50% or more in the visible light range and transmittance in the visible light range
The above film has a particle size of 1 μm
The following white pigment or pearl pigment is added to the binder in an amount of 50 to
The structure is made of a material dispersed at a ratio of 90% by weight .

Therefore, since the above-mentioned film has a diffuse reflection property, the reflective display becomes bright, and since the above-mentioned film has a light-shielding property, the transmissive display has a high contrast. There is an effect that an appropriate liquid crystal display device can be provided as a reflection / transmission type.

[0072]

By setting the particle size of the white pigment or pearl pigment to 1 μm or less, the diffuse reflectance of the above film to light can be 50% or more in the visible light range.
As a result, the reflective display can be made bright, 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 to suppress light leakage from between pixels. Further, by dispersing a white pigment or a pearl pigment in a binder at a ratio of 90% by weight or less, the above film can be easily cured even when a resin is used for the binder, and the film can be easily formed. This has the effect.

In the liquid crystal display device of the reflection / transmission type according to the second aspect of the present invention, as described above, the film of the first aspect is formed of a transparent substrate opposed to the liquid crystal layer. On the other hand, it is configured to be formed in a pattern corresponding to the shape between pixels.

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

The reflection / transmission type liquid crystal display device according to the third aspect of the present invention, as described above, comprises two transparent substrates facing each other with a liquid crystal layer interposed therebetween, and a transparent substrate facing each other. A transparent electrode formed in a stripe shape in a direction orthogonal to each other on the surface, wherein the film according to claim 1 is on a facing surface of each transparent substrate and in a gap between the transparent electrodes. It is a configuration that has been formed.

Therefore, by forming the above-mentioned film in the gap between the transparent electrodes, the above-mentioned film is formed without a gap between all the pixels. This has the effect that light leakage from between pixels can be sufficiently suppressed.

[0078] reflection and transmission compatible type of <br/> liquid crystal display device according to the fourth aspect of the present invention, as described above, the film according to claim 3, the resistivity of the liquid crystal material forming the liquid crystal layer This is a configuration formed of a material having a larger specific resistance.

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

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one configuration example of a liquid crystal display device according to the present invention.

FIG. 2 is a perspective view showing a shape of a reflection 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 longitudinal sectional view showing another configuration example of the liquid crystal display device according to the present invention.

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

FIG. 6 is a longitudinal sectional view showing one configuration example of a liquid crystal display device as a first comparative example.

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

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

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

11 is an explanatory diagram schematically showing a state between pixels in black and white display of the liquid crystal display device shown in FIG. 6;

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

FIG. 13 is a longitudinal sectional view illustrating a configuration example of a conventional liquid crystal display device.

[Explanation of symbols]

 DESCRIPTION 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

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-2-24604 (JP, A) JP-A-6-18714 (JP, A) JP-A-62-247625 (JP, A) JP-A-6-47625 331975 (JP, A) JP-A-7-248405 (JP, A) JP-A-7-270771 (JP, A) JP-A-7-270774 (JP, A) JP-A-7-270772 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G02F 1/1335

Claims (4)

(57) [Claims] 1. A half of a liquid crystal display panel on a side opposite to a display surface.
A reflective / transmission type liquid crystal display device with a transmission / reflection plate
In location, between pixels of the liquid crystal display panel, diffuse reflective to light
And a light-shielding single-layer film, and the film has a diffuse reflectance of 5 to visible light in the visible light region.
The above film is obtained by dispersing a white pigment or a pearl pigment having a particle size of 1 μm or less in a binder at a ratio of 50 to 90% by weight so that the transmittance is 0% or more and the transmittance is 5% or less in a visible light region. and anti, characterized in that the material is formed by
A liquid crystal display device for both emission and transmission . Wherein said film is reflective described one in transparent substrate opposed by interposing a liquid crystal layer, to claim 1, characterized in that it is formed in a pattern corresponding to the shape between pixels
・ Transmissive dual-purpose liquid crystal display device. 3. A transparent substrate comprising: two transparent substrates facing each other with a liquid crystal layer interposed therebetween; and transparent electrodes formed in stripes in directions orthogonal to each other on opposite surfaces of each transparent substrate. 2. The reflection / transmission type liquid crystal display device according to claim 1, wherein the reflection / transmission type liquid crystal display device is formed on a facing surface of each transparent substrate and in a gap between the transparent electrodes. 4. The reflection / transmission system according to claim 3 , wherein said film is formed of a material having a specific resistance higher than that of a liquid crystal material forming said liquid crystal layer.
Type liquid crystal display device.