JP2001154180A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device by which bright display can be obtained without influence of the external light. SOLUTION: The transmission type liquid crystal display device is equipped with a liquid crystal layer, first and second circularly polarizing layers disposed above and below the liquid crystal layer to interpose the liquid crystal layer, an optically selecting layer which selectively reflects light of a specified polarization component and transmits other light components, and an absorbing layer which absorbs the reflected light in a specified wavelength region. The liquid crystal layer satisfies the condition n+1/2 λ and n λ (wherein n is 0, 1, 2, and λis the all wavelengths of light entering the liquid crystal layer) according to the input signal. The optically selecting layer is disposed between the liquid crystal layer and the second circularly polarizing layer.

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, and more particularly, to a transmission type liquid crystal display.

[0002]

2. Description of the Related Art Conventionally, for a liquid crystal display device using cholesteric liquid crystal, Merck Ltd. of the United Kingdom has been working on IDW'96 to improve the efficiency of using light emitted from a backlight.
(Vol. 2, pp. 309-312) "Advances In Reflective Polar"
isers ”, SID'96 APPLICATIONS DIGEST (pages 67-70)
A4.3 "High-Perfomance Wide-Bandwidth Refl
ective Cholesteric Polarizers.

The principle of this liquid crystal display device will be described with reference to FIG. Referring to FIG. 5, the left side shows the case where a voltage is applied to the liquid crystal layer 75, and the right side shows the case where no voltage is applied to the liquid crystal layer 75. In this liquid crystal display device,
When the unpolarized light emitted from the backlight 100 enters the cholesteric layer 90, 50% of the right circularly polarized light component is transmitted, and the remaining 50% of the left circularly polarized light component is reflected. The transmitted right circularly polarized light component is converted into linearly polarized light by the next ４λ plate. The reflected left circularly polarized light component returns to the backlight,
Since the light is diffused and reflected by a scattering plate, a prism sheet, a reflection plate, and the like, which are components of the backlight, the phase is lost and becomes unpolarized light, and most of the light enters the cholesteric layer 90 again. By repeating this, the use efficiency of light emitted from the backlight 100 is improved.

[0004] The converted linearly polarized light is supplied to a polarizing plate 80,
When the light passes through the liquid crystal layer 75 and no voltage is applied to the liquid crystal layer 75, the light is emitted from the polarizing plate 70. When a voltage is applied to the liquid crystal layer 75, the light is not emitted from the polarizing plate 70. However, when performing color display, since an absorption type color filter layer is further used for the liquid crystal layer 75, the polarizing plate 70 is used.
From the light is reduced to 1/3.

When a voltage is applied to the liquid crystal layer 75, the light from the external light 71 is absorbed by the polarizing plate 80, and when no voltage is applied to the liquid crystal layer 75, the light is transmitted to the backlight 100 and the backlight 100 is transmitted. It is mixed with the unpolarized light emitted from 100.

That is, in this liquid crystal display device,
Although display can be performed without being affected by external light, a decrease in brightness has been a problem in the case of performing color display because an absorption type color filter layer is used.

As for a liquid crystal display device using cholesteric liquid crystal, Seiko Epson discloses the structure as a transflective LCD structure in Japanese Patent Application Laid-Open No. Hei 10-333175. Such a transflective type uses a complementary color of a color displayed in the transmissive mode for display in the reflective mode. Therefore, when used in the transmission mode, the display is such that the transmission color and the complementary color are mixed due to the influence of external light, and the display becomes difficult to see.

Further, regarding a liquid crystal display device using a cholesteric liquid crystal, CLCEO of the United States has issued SID'99 (1063-106).
51.3) 51.3 “Cholesteric Color Filters: Optical
Characteristics, Light Recycling, and Brightness E
nhancement].

The principle of the liquid crystal display will be described with reference to FIG. Referring to FIG. 6, the left side shows the case where a voltage is applied to the liquid crystal layer 120, and the right side shows the case where no voltage is applied to the liquid crystal layer 120. In this liquid crystal display device, the clockwise Broadband cholesteric film 150, counterclockwise cholesteric CF (color filter) layer 1 that reflects only a specific wavelength
40, 1 / 4λ plate 130, TN liquid crystal layer 120, polarizing plate 1
The layers are stacked in the order of 10.

First, the non-polarized light 1 from the backlight 160
62 is a clockwise broadband cholesteric film 15
0, right-handed circularly polarized light is reflected back to the backlight 160, diffused, reflected, converted into unpolarized light, and again clockwise broadband cholesteric film 15
Incident at 0.

The transmitted counterclockwise circularly polarized light is reflected by the counterclockwise cholesteric CF layer 140 reflecting only a specific wavelength.
In a layer that transmits, for example, counterclockwise red (R) circularly polarized light, counterclockwise cyan (C) circularly polarized light is reflected and transmitted through the clockwise broadband cholesteric film 150. Then, the light returns to the backlight 160, is diffused and reflected, is converted into cyan (C) non-polarized light, and is incident on the clockwise broadband cholesteric film 150 again.
When the transmitted counterclockwise cyan (C) circularly polarized light is then incident on a layer that transmits counterclockwise green (G) circularly polarized light, the counterclockwise blue (B) circularly polarized light is transmitted. Is reflected and transmitted through the clockwise wideband cholesteric film 150, returns to the backlight 160, diffuses and reflects, is converted into blue (B) unpolarized light, and is incident on the clockwise wideband cholesteric film 150 again. I do. When the transmitted counterclockwise blue (B) circularly polarized light is then incident on a layer that transmits the counterclockwise blue (B) circularly polarized light, it can transmit all counterclockwise circularly polarized light. it can.

The transmitted left-handed circularly polarized lights of R, G, and B are incident on the １ ／ λ plate 130, and are transmitted to the R, G, and B lights.
The light is converted into each linearly polarized light and enters the TN liquid crystal layer 120. When no voltage is applied to the TN liquid crystal layer 120, the linearly polarized light is applied to the TN liquid crystal layer 120,
The light is emitted from the polarizing plate 110. When a voltage is applied to the TN liquid crystal layer 120, the light passes through the TN liquid crystal layer 120 and is absorbed by the polarizing plate 110.

The external light 111 is transmitted by the polarizing plate 110 through only one linearly polarized light. When no voltage is applied to the TN liquid crystal layer 120, the light is applied by the TN liquid crystal layer 120, converted into counterclockwise circularly polarized light by the ４λ plate 130, and counterclockwise cholesteric reflecting only a specific wavelength. The light enters the CF layer 140. In the cholesteric CF layer 140, for example,
If the layer emits R, the left-handed circularly polarized C light is reflected, converted to linearly polarized light by the ４λ plate 130, applied to the TN liquid crystal layer 120, and emitted from the polarizing plate 110 (M , Y).

When a voltage is applied to the TN liquid crystal layer 120, the light passes through the TN liquid crystal layer 120, is converted into right-handed circularly polarized light by the ４λ plate 130, and passes through the left-handed cholesteric CF layer 140. Then, the light enters the clockwise broadband cholesteric film 150. The right-handed circularly-polarized light reflected by the cholesteric film 150 passes through the left-handed cholesteric CF layer 140 and becomes 1 / 4λ.
The light is converted into linearly polarized light by the plate 130, passes through the TN liquid crystal layer 120, and is emitted from the polarizing plate 110.

[0015]

As described above, in the conventional transmission type liquid crystal display device, when performing color display, the surface reflection due to external light and the reduction of the display contrast have been problems.

Accordingly, an object of the present invention is to provide a transmission type liquid crystal device using a cholesteric filter, which is not affected by external light and can provide a bright display.

[0017]

In order to achieve the above object, a liquid crystal display device according to the present invention is directed to a transmission type liquid crystal display device, wherein a liquid crystal layer is disposed above and below the liquid crystal layer with the liquid crystal layer interposed therebetween. , A first and second circularly polarizing layer, an optical selection layer that selectively reflects only light of a specific polarization component and transmits other light, and absorbs reflected light of a specific wavelength range. An absorption layer, wherein the liquid crystal layer is in a condition of n + 1 / 2λ and nλ (n = 0, 1, 2,..., Λ is the total wavelength of light incident on the liquid crystal layer) according to an input signal; The optical selection layer is disposed between the liquid crystal layer and the second circularly polarizing layer.

More preferably, the absorption layer transmits light in the same wavelength range as the optical selection layer, and the optical selection layer and the absorption layer are pixelated. .

Preferably, a polarization splitting layer is disposed between the second circularly polarizing layer and a backlight light source, wherein the first and second circularly polarizing layers are
It is characterized by comprising a polarizing plate and at least one retardation film.

Further, preferably, the optically selective layer contains a cholesteric liquid crystal, a chiral nematic liquid crystal or a chiral smectic liquid crystal, and uses a liquid crystal or a liquid crystalline polymer in which the material is formed into a film or microencapsulated. .

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the principle of the present invention will be described with reference to FIGS. FIG. 1 is an explanatory diagram when a voltage is applied to the liquid crystal layer in the liquid crystal display device according to the present invention, and FIG. 2 is an explanatory diagram when no voltage is applied to the liquid crystal layer of the same display device.

In the liquid crystal display device shown in FIG. 1, an absorption type color filter layer 30, a liquid crystal layer 20 (voltage application) and a first circularly polarizing layer 10 are provided in this order on the upper side of the cholesteric color filter layer 40. Has a second circularly polarizing layer 50 and a backlight 60 in this order.

First circularly polarizing layer 10 and second circularly polarizing layer 5
0 has a polarizing plate and a quarter-wave plate, respectively.
In these circularly polarizing layers 10 and 50, the absorption axis of the polarizing plate and the slow axis of the quarter-wave plate are arranged so as to be left-handed circularly polarized light, respectively.

A cholesteric liquid crystal has the property of reflecting light having the same wavelength as the pitch of the liquid crystal, circularly polarized light in the same rotation direction as the liquid crystal, and transmitting other light. Therefore, for example, when a cholesteric liquid crystal layer having a pitch of 500 nm and counterclockwise is used for the cholesteric liquid crystal layer, left circularly polarized light having a wavelength of 500 nm is reflected, and right circularly polarized light and left circularly polarized light having other wavelengths are transmitted. It becomes a liquid crystal element.

Further, by using a left-handed cholesteric liquid crystal and changing the pitch in the cholesteric liquid crystal over the wavelength range of the cyan color component, the left-handed circularly polarized light of cyan is reflected, and the right-handed circularly polarized light is reflected. And a layer that transmits the left circularly polarized light of the red and red color components.

Similarly, C (cyan), M (magenta), and Y of left circularly polarized light are changed in the cholesteric liquid crystal over the respective wavelength ranges of magenta and yellow.
(Yellow) light, right circularly polarized light and left circularly polarized R
A cholesteric color filter layer 40 that transmits (red), G (green), and B (blue) light is obtained.
When the light from the backlight 60 is transmitted, the absorption type color filter layer 30 is separated into R, G, B and three lights. The liquid crystal layer 20 has a half wavelength condition when no voltage is applied.

Next, light from a light source of the liquid crystal display device will be described. The scattered light 62 from the BL (backlight) light source 61 is incident on the second circularly polarizing layer 50 and transmits only left circularly polarized light (light use efficiency from the backlight 50%). The transmitted left circularly polarized light is incident on the left-handed cholesteric color filter layer 40. For example, in a region where the left-handed red (R) circularly-polarized light is transmitted, the left (R) left circularly-polarized light is transmitted. Transmits only light. The left circularly polarized light of cyan (C) reflected by the left-handed cholesteric color filter layer 40 passes through the second circularly polarized light layer 50, is converted into linearly polarized light, is scattered by the backlight 60, and is It becomes the scattered light of (C). The scattered light of cyan (C) again enters the second circularly polarizing layer 50, transmits only the left-handed circularly polarized cyan (C) light, and enters the left-handed cholesteric color filter layer 40. Next, when the light enters a region that transmits green (G) circularly polarized light, only green (G) left circularly polarized light is transmitted. The left circularly polarized light of blue (B) reflected by this region is transmitted through the second circularly polarized light layer 50, is converted into linearly polarized light, and is
The light is scattered at 0 and becomes scattered light of blue (B). The blue (B) scattered light enters the second circularly polarizing layer 50 again, transmits only the left-handed blue (B) circularly polarized light, and enters the left-handed cholesteric color filter layer 40.
Next, when the light enters a region that transmits blue (B) circularly polarized light, only blue (B) left circularly polarized light is transmitted.

That is, the counterclockwise cholesteric color filter layer can recycle the left circularly polarized light of C, M, and Y reflected in each area, and can reduce the light use efficiency by the conventional liquid crystal display device. Can be further improved.

Here, if an optical member that transmits left-polarized light and reflects right-polarized light is provided below the second circularly-polarized layer 50, the right-polarized light is also effectively used. The light use efficiency is further improved.

The transmitted R, G, B left circularly polarized light passes through the absorption type color filter layer 30 and the liquid crystal layer 20 as it is and enters the first circularly polarized light layer 10. The left circularly polarized light of R, G, and B incident on the first circularly polarized light is converted into linearly polarized light and emitted. That is, light from the backlight 60 is emitted to the surface of the liquid crystal display device.

The external light 11 is incident on the first circularly polarized light layer 10 and transmits only left circularly polarized light. The left circularly polarized light passes through the liquid crystal layer 20 as it is, enters the absorption type color filter layer 30, and is separated into R, G, and B left circularly polarized light. For example, the light separated into red (R) left-handed circularly-polarized light is directed to the counterclockwise cholesteric color filter layer 40.
Is transmitted as it is, and is incident on the second circularly polarizing layer 50, where it is converted into red (R) linearly polarized light. The red (R) linearly polarized light is scattered and reflected by the backlight 60 to become red (R) scattered light.
Is incident on the circularly polarizing layer 50. This second circularly polarizing layer 50
The left-handed circularly-polarized light of red (R) transmitted through the cholesteric color filter layer 40 of the left-handed cholesteric color filter layer 40
When the light is incident on a region that transmits light, the counterclockwise cholesteric color filter layer 40, the absorption type color filter layer 30,
The light passes through the liquid crystal layer 20 and enters the first circularly polarizing layer 10.
The red (R) left-handed circularly polarized light incident on the first circularly polarizing layer 10 is converted into red (R) linearly polarized light and emitted. (The same applies to G and B.) That is, the light from the external light 11 is also emitted to the surface of the liquid crystal display device without color inversion. Therefore, when a voltage is applied to the liquid crystal layer 20, a sufficiently bright display that is not affected by external light can be made.

Next, referring to FIG. 2, the liquid crystal display device is the same as that of FIG. The light from the light source of the liquid crystal display will be described. The scattered light from the backlight 60 is converted and separated as in FIG. When the R, G, and B left circularly polarized light incident on the liquid crystal layer 20 passes through the liquid crystal layer 20 (1 / 2λ condition),
The light is converted to right circularly polarized light of R, G, and B. This R, G,
Since the right circularly polarized light B enters the first circularly polarized light layer and is absorbed there, the light from the backlight 60 is not emitted to the surface of the liquid crystal display device.

External light 11 enters the first circularly polarizing layer,
Transmits only left circularly polarized light. The left circularly polarized light is incident on the liquid crystal layer 20 (1 / 2λ condition) and is converted into right circularly polarized light. The right circularly polarized light is incident on the second circularly polarized light layer 50 by the absorption type color filter layer as in the case of FIG. R, G, and R incident on the second circularly polarizing layer 50
Since the right circularly polarized light of B is absorbed there, external light is not emitted to the surface of the liquid crystal display device.

From the above, when no voltage is applied to the liquid crystal layer 20 (1 / 2λ condition), the liquid crystal layer 20 is not affected by external light,
A sufficiently dark display becomes possible. That is, this liquid crystal display device can provide a bright liquid crystal display device which is not affected by external light and can perform high-contrast display.

Next, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment> FIG. 3 is an exploded sectional view of a liquid crystal display device according to a first embodiment, in which a liquid crystal panel 245 (1 / 2λ condition) is used. Above the liquid crystal panel 245, an absorption filter 250 is provided. Above the liquid crystal panel 245, a λλ plate 220 and a polarizing plate 210 are provided.
Are arranged so as to transmit left circularly polarized light, and are provided in this order. On the lower side of the liquid crystal panel 245, a counterclockwise cholesteric color filter layer 266, a λλ plate 270, a polarizing plate 280, and a backlight 290 are provided in this order. The 1 / 4λ plate 270 and the polarizing plate 280
Are arranged to transmit the left circularly polarized light.

The liquid crystal panel 245 (cell thickness: 3 μm, liquid crystal Δn 0.09) is manufactured so as to have a retardation of 270 nm. 7059 manufactured by Corning Incorporated was used for the glass substrate holding the liquid crystal. Transparent electrodes 231 and 235 made of ITO (Indium Tin Oxide) or tin oxide are provided on the lower surface of the glass substrate 230 and the upper surface of the glass substrate 240 of the liquid crystal panel 245. This time, SiO ₂ was formed as a base film on the glass substrates 230 and 240 by 200 ° sputtering, and ITO was continuously formed on the film by 1000 ° sputtering.
Was patterned using bromoic acid (48%).

The lower surface of the transparent electrode 231 and the transparent electrode 23
5 was provided with polyimide alignment films 232 and 234, and rubbing treatment was performed. The glass substrates 230 and 2
And 40 are fixed so that the rubbing direction is parallel (anti-parallel), and a sealing material (containing 3 μm particles) is used.
Laminated, Merck's nematic liquid crystal 233 (ML
C-6221 Δn = 0.091), and sealed.

As a material of the cholesteric liquid crystal polymer layer 265, a photopolymerizable Wacker-Chemie is used.
TC3951L manufactured by GmbH is used. This TC
3951L can change the reflection spectrum at a specific temperature by the thermochromic effect of the cholesteric phase due to the temperature dependence of the helical twist power of the chiral material.

First, TC395 is placed on a glass substrate 252.
A 1 L film is formed. The temperature of the glass substrate 252 is set at 76 ° C. (corresponding to the reflection of green light), and UV irradiation is performed to fix the green reflection filter layer. Subsequently, the temperature of the glass substrate 252 is set to 105 ° C. (corresponding to the reflection of blue light), and UV irradiation is performed to fix the blue reflection filter layer.
As described above, the cholesteric filter 266 of the cyan light reflection type is formed. In the present embodiment, it is set so as to reflect counterclockwise circularly polarized light.

In the liquid crystal display device of the first embodiment, a cholesteric color filter 266 is attached below the liquid crystal panel 245, and a left circularly polarized light is provided above the liquid crystal panel 245 and below the cholesteric color filter 266. Λλ plates 220 and 270 and polarizing plates 210 and 280 set so as to transmit light of. The backlight 290 emits light emitted from the backlight light source 291 upward by a light guide.

In a conventional transmission type liquid crystal display device using a cholesteric reflection layer, since no absorption layer is used, when external light is incident, a complementary color is reflected, display is difficult to see (double reflection), and black display is possible. There were problems such as no (low contrast). However, in the liquid crystal display device manufactured in (First Embodiment), the structure is not affected by external light when a voltage is applied to the liquid crystal layer 233 and when the voltage is not applied. It was confirmed that display was possible (high contrast display).

<Second Embodiment> FIG. 4 is an exploded sectional view of a liquid crystal display device according to a second embodiment. The difference between the liquid crystal display device of the present embodiment and the first embodiment is that an absorption color filter 255 that is made into pixels is provided on the glass substrate 230 side of the liquid crystal layer 233 and that a pixel is provided below the color liquid crystal panel 246. That the cholesteric color filter 260 is
The point is that the polarization separation layer 285 is disposed below the broadband λλ plate 220 and the polarizing plate 210 set so as to transmit the left circularly polarized light from the 0 side.

Color liquid crystal panel 246 (cell thickness: 3 μm)
m, Δn 0.09 of the liquid crystal), a retardation of 270 nm was produced in the same manner as in the first embodiment, and a color filter 255 with high brightness was arranged. Then, as an example of the light absorption type color filter 255, a pigment dispersion type color filter was produced as follows.

First, a photosensitive colored resist in which a red pigment is uniformly dispersed in a transparent photosensitive resin is applied to a glass substrate 2.
Apply on top of 30. Specifically, using CR2000 manufactured by Fuji Hunt Electronics Technology Co., Ltd.
A film having a thickness of 2.0 μm is formed by spin coating at 650 rpm. Thereafter, the film is prebaked at 80 ° C., exposed and developed using a predetermined mask, and finally baked at 220 ° C. for 30 minutes to form a red pattern. Furthermore, Fuji Hunt Electronics Technology Co., Ltd.
G2000, CB2000, and CK2000 are formed in the same process to form green, blue, and black patterns, respectively, to form a color filter layer 255. Further, various methods such as a gelatin dyeing method, an electrodeposition method, and a printing method can be applied to the absorption type color filter used as the color filter layer 255.

Further, as an example of the cholesteric color filter 260 in the form of a pixel, a cholesteric liquid crystal polymer layer 265 was manufactured as in the first embodiment. First, a film made of TC3951 is formed on a glass substrate 252, and a predetermined mask corresponding to a pixel is arranged. In order to create a region through which red light is transmitted, the temperature of the glass substrate is set to 76 ° C. as the first layer of the red region.
(Corresponding to the reflection of green light), a predetermined mask corresponding to the pixel is arranged, and UV irradiation is performed to fix the area of the green reflection filter. Next, as the second layer, TC39 was again used.
A film made of 51L is formed, and the temperature of the glass substrate is set to 105
° C (corresponding to the reflection of blue light), a predetermined mask corresponding to the pixel is arranged, and the area of the blue reflection filter is fixed by irradiating UV, and red is transmitted (cyan light reflection type). Cholesteric regions are formed. Furthermore, in the same process, green (first layer: red, second layer: blue) and blue (first layer: red, second layer: green)
A region through which the light was transmitted was prepared. As described above, the cholesteric color filters 260 of the cyan, magenta, and yellow light reflection types are formed.

The TC3951L film corresponds to red light when the glass substrate is heated to 25 ° C., corresponds to green light when the glass substrate is heated to 76 ° C., and has a glass substrate temperature of 105 ° C. When heated, it corresponds to blue light. In the present embodiment, the counterclockwise circularly polarized light is set to be reflected.

As an example of the polarization separation layer 285, Sumitomo 3M
DBEF manufactured by the company was used. This DBEF was arranged such that the linearly polarized light transmitted from the backlight 290 side and the transmission axis of the polarizing plate 280 were parallel.

When the liquid crystal display layer device of the second embodiment was driven and its luminance was measured by a luminance meter (BM-7), it was found to be about 6 times as bright as that of a conventional absorption type LCD. (Equivalent to the liquid crystal display of CLCEO, USA). Also, when a voltage is applied to the liquid crystal layer and when no voltage is applied,
It was also confirmed that a display not affected by external light was obtained.

<Third Embodiment> In the liquid crystal display device of the third embodiment, a broadband 1 /
Instead of 4λ plate 220 and polarizing plate 210, Merck T
ransmax (broadband cholesteric liquid crystal layer (reflects counterclockwise)). When the manufactured liquid crystal display device is driven and its luminance is measured by a luminance meter (BM-7),
Approximately 6 times the brightness (US CL) compared to the conventional absorption LCD
(Equivalent value to the liquid crystal display device of CEO). Also,
It was also confirmed that a display which was not affected by external light was obtained when a voltage was applied to the liquid crystal layer and when no voltage was applied.

In the first to third embodiments, the NB (normally black) mode is set.
If it is arranged to transmit right circularly polarized light, it can be set to NW (normally white) mode.

Further, in the first to third embodiments, the cholesteric liquid crystal polymer is used for the optically selective layer, but the cholesteric liquid crystal, the chiral nematic liquid crystal, or the chiral smectic liquid crystal is included, and the liquid crystal or the microcapsule is formed from the above liquid crystal or It was confirmed that a similar effect was obtained even when a liquid crystalline polymer was used.

In the above embodiment, the liquid crystal display system in which the amount of birefringence can be controlled by an external field is a parallel-aligned EC.
Although a B-type liquid crystal cell is employed, the same effect can be obtained even when a vertical alignment or STN method is used as a liquid crystal display method having the same effect, and an excellent effect that large-capacity display by simple matrix driving becomes possible. Demonstrate.

The liquid crystal is not limited to liquid crystal as long as it exhibits birefringence and the amount of birefringence can be controlled by an external field.
A similar effect can be obtained by forming a transparent electrode on an optical crystal such as LZT or lithium niobate and applying a voltage to vary the amount of birefringence. Further, in this case, it is possible to operate at a high speed and also exhibit an excellent feature of having a memory property.

[0055]

According to the liquid crystal display device of the present invention, a structure free from the influence of external light can be provided, and a high-contrast display can be achieved. In addition, reflected light or light from a light source can be recycled by the optical selective layer, and light utilization efficiency can be improved.

In a further aspect of the present invention, the transmitted light can be broadened, and the loss of light can be reduced. That is, since the liquid crystal display device according to the present invention is not affected by external light, the display can be easily viewed even in a bright environment.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle when a voltage is applied to a liquid crystal layer of a liquid crystal display device of the present invention.

FIG. 2 is a diagram illustrating the principle when no voltage is applied to the liquid crystal layer of the liquid crystal display device of the present invention.

FIG. 3 is an explanatory diagram of the liquid crystal display device according to the first embodiment.

FIG. 4 is a diagram illustrating a liquid crystal display device according to a second embodiment.

FIG. 5 is an explanatory diagram of a conventional liquid crystal display device.

FIG. 6 is an explanatory view of a conventional liquid crystal display device.

[Explanation of symbols]

10 Circular polarizing layer (counterclockwise) 11, 71, 111 Outside light 20 Liquid crystal layer 30 Absorption type color filter layer 40, 90, 140 Cholesteric liquid crystal layer (reflecting counterclockwise) 50 Circular polarizing layer (counterclockwise) 60, 100 160 BL system 61, 101, 161 BL light source 62, 102, 162 Light from BL light source 70, 80, 110 Polarizer 75, 120 TN liquid crystal layer 85, 130 1/4 λ plate 150 Broadband cholesteric liquid crystal film (reflection clockwise) ) 210, 280 Polarizing plate 220, 270 1/4 λ plate 230, 240, 252 Glass substrate 231, 235 Transparent electrode 232, 234 Alignment film 233 Liquid crystal layer 236 Sealing member 245 Liquid crystal panel 250 Absorption filter 255 Absorption color filter 260 Cholesteric color filter 265 cholesteric liquid Polymer layer 266 cholesteric filter 285 optical film 290 BL system 291 BL source

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shun Ueki 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (72) Inventor Seiichi Mitsui 22-22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka 2H048 AA01 AA06 AA09 AA12 AA18 AA22 AA24 AA25 BA02 BA45 BB02 BB10 BB14 BB42 2H091 FA08X FA08Z FA09Z FA11Z FD06 HA09 HA10 LA03 LA17

Claims (6)

[Claims] 1. A transmissive liquid crystal display device, comprising: a liquid crystal layer; first and second circularly polarizing layers disposed above and below the liquid crystal layer with the liquid crystal layer interposed therebetween; An optical selection layer that selectively reflects only light and transmits the other light, and an absorption layer that absorbs the reflected light in a specific wavelength range, wherein the liquid crystal layer has n + 1 / 2λ according to an input signal.
And nλ (where n = 0, 1, 2,..., Λ is the total wavelength of light incident on the liquid crystal layer), and the optical selective layer is disposed between the liquid crystal layer and the second circularly polarizing layer. A liquid crystal display device characterized by being arranged in a liquid crystal display device. 2. The liquid crystal display device according to claim 1, wherein the absorption layer transmits light in the same wavelength band as the optical selection layer. 3. The liquid crystal display device according to claim 1, wherein the optical selection layer and the absorption layer are pixelated. 4. The liquid crystal display device according to claim 1, wherein a polarization splitting layer is disposed between the second circularly polarizing layer and a backlight light source. 5. The liquid crystal display device according to claim 1, wherein the first and second circularly polarizing layers are formed using a polarizing plate and at least one retardation film. 6. A liquid crystal or liquid crystalline polymer comprising a cholesteric liquid crystal, a chiral nematic liquid crystal, or a chiral smectic liquid crystal as the optically selective layer, wherein the material is formed into a film or microencapsulated. Or the liquid crystal display device according to 3.