JP2003075829A - Reflection type liquid crystal device and electronic instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflection type liquid crystal device with which bright display can be realized and which has excellent contrast and display quality. SOLUTION: A reflection type liquid crystal device 10 displays images by switching a liquid crystal layer into a uniform state or a focal conic state. A reflection type hologram color filter 22 provided with hologram elements 22R, 22G and 22B which transmit light made incident from the direction nearly equal to the incidence direction of light made incident on an element substrate 30 and which reflect light of a specific wavelength made incident to the liquid crystal layer and diffracted by the liquid crystal layer when the liquid crystal layer is in the focal conic state is formed on the liquid crystal layer side of a counter substrate 20 positioned on the side opposite to a light incident side among a pair of substrates disposed opposite to each other having the liquid crystal layer interposed there between, and a light absorbing body 24 is formed on the side opposite to the light incident side of the reflection type hologram color filter 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflective liquid crystal device capable of realizing a bright display, excellent in contrast and excellent in display quality, and an electronic apparatus equipped with the reflective liquid crystal device. .

[0002]

2. Description of the Related Art Conventionally, as a liquid crystal device, external light such as sunlight enters the liquid crystal device from the observer side, is reflected in the liquid crystal device, and then is emitted to the observer side to perform display. Type liquid crystal devices are known. However, in the conventional reflection type liquid crystal device, about 55% of the light incident on the liquid crystal device is absorbed by the polarizer provided on the observer side of the liquid crystal device, so that a backlight is built in and emitted from the backlight. There is a problem in that the brightness of the display is inferior to that of a transmissive liquid crystal device that displays by the generated light. Also,
In a conventional reflective liquid crystal device equipped with a polarizer, the birefringence of the liquid crystal was used to control the light that passed through the polarizer and the light that did not pass through it. In some cases, the light was emitted to the side, and pure black display could not be obtained.

Therefore, in recent years, a liquid crystal layer is switched between a light-scattering state and a light-transmitting state as a reflection type liquid crystal device capable of displaying without using a polarizer and improving the brightness of the display. Thus, a reflective liquid crystal device that performs display (hereinafter, referred to as "scattering reflective liquid crystal device").
Has been proposed, for example, polymer dispersed liquid crystal (PDL)
A polymer dispersion type reflective liquid crystal device having a liquid crystal layer composed of C) is known.

In such a scattering type reflection type liquid crystal device, white display can be performed when the liquid crystal layer is in the light scattering state, and black display can be performed when the liquid crystal layer is in the light transmitting state. That is, when the liquid crystal layer is in the light-scattering state, light incident from various directions is scattered in the liquid crystal layer and is emitted in various directions. Therefore, a large amount of light is emitted in the observation direction of the observer, and white light is emitted. The display can be done. On the other hand, in order to perform black display when the liquid crystal layer is in a light transmitting state, a structure is provided in which a light absorber that absorbs light that has passed through the liquid crystal layer is provided, or a light reflector that reflects light that has passed through the liquid crystal layer is provided. Uses either configuration. According to the former configuration, since there is no light emitted to the observer side, black display can be performed. On the other hand, according to the latter configuration, only the light whose reflection direction matches the observation direction of the observer can be visually recognized, and the amount of light visually recognized by the observer is small, so that black display can be performed. .

[0005]

In a scattering type reflection type liquid crystal device for providing a black display by providing a light absorber, when the liquid crystal layer is in the light transmitting state, light is not emitted to the observer side, so that the brightness is low. Although black display can be realized, when the liquid crystal layer is in a light-scattering state, the light scattered by the liquid crystal layer on the side opposite to the observer is absorbed by the light absorber, so the brightness of white display decreases. As a result, there is a problem that the brightness and contrast of the display are lowered.

Further, in a scattering type reflection type liquid crystal device for providing a black display by providing a light reflector, when the liquid crystal layer is in a light scattering state,
The light scattered by the liquid crystal layer on the side opposite to the viewer side is reflected by the light reflector and emitted to the viewer side, so that white display with high brightness (brightness), so-called paper white, can be realized. Although it is possible, even when the liquid crystal layer is in the light transmitting state, a part of the light transmitted through the liquid crystal layer is reflected by the light reflector and is emitted to the observer side. However, there is a problem in that the contrast is lowered as a result. Further, when the liquid crystal layer is in the light transmitting state, if the brightness of the external light is high, the face of the observer may be reflected on the light reflector, and the display quality may be deteriorated.

Therefore, the present invention has been made in view of the above circumstances, and it is possible to realize a bright display and to provide a reflective liquid crystal device which is excellent in contrast and display quality, and this reflective liquid crystal device. It is an object of the present invention to provide an electronic device equipped with.

[0008]

As a result of studies to solve the above problems, the present inventor has invented the following reflective liquid crystal device of the present invention. The reflection type liquid crystal device of the present invention is a reflection type liquid crystal device including a first substrate and a second substrate which are arranged to face each other, and a liquid crystal layer sandwiched between the pair of substrates. It is possible to switch between a conic state and a uniform state, and the first substrate side is a light incident side, and the light incident on the first substrate is incident on the liquid crystal layer side of the second substrate. A plurality of types of reflection that transmits light that is incident from substantially the same direction as that of the light that is transmitted, and that is incident on the liquid crystal layer when the liquid crystal layer is in the focal conic state and that reflects light of a specific wavelength diffracted by the liquid crystal layer. A reflective color filter is provided, wherein different types of reflective elements reflect light of different wavelengths, and a light absorber is formed on the side opposite to the light incident side of the reflective color filter. And wherein the are.

In the present specification, "the liquid crystal layer is in the focal conic state" means that the liquid crystal molecules are helically twisted and aligned throughout the entire liquid crystal layer, and the helical axes of all the liquid crystal molecules are arranged. Are aligned in substantially the same direction, and that direction is a direction that is non-parallel to the normal direction of the surface of the first substrate (second substrate). Further, "the liquid crystal layer is in a uniform state" means a state in which the major axis directions of all liquid crystal molecules in the liquid crystal layer are aligned in substantially the same direction.

FIG. 6 schematically shows a plan view of the liquid crystal layer in the focal conic state when the spiral axis is parallel to the substrate surface, as seen from the light incident side. Based on this figure, the focal conic state is shown. The properties of the liquid crystal layer in the state will be described. 6 is a diagram showing a state in which the liquid crystal molecules 100 are twisted and arranged in a spiral shape from the left direction in the drawing toward the right direction in the drawing, and reference numerals 100a and 100b respectively denote the liquid crystal molecules 10.
0, liquid crystal molecules whose major axis direction is horizontal to the substrate surface,
Shows vertical liquid crystal molecules.

When the spiral axis is parallel to the substrate surface,
In the liquid crystal layer, the region 110 in which the angle between the long axis direction of the liquid crystal molecule 100 and the substrate surface is 0 to 45 °, and the angle between the long axis direction of the liquid crystal molecule 100 and the substrate surface is 45 to 90 °. A certain area 120 is alternately repeated. Since the liquid crystal molecule 100 has birefringence exhibiting different refractive indices on the major axis side and the minor axis side, the effective refractive index of the liquid crystal layer is
The region 110 in which the angle between the long axis direction of 00 and the substrate surface is 0 to 45 ° and the region 120 in which the angle between the long axis direction of the liquid crystal molecules 100 and the substrate surface is 45 to 90 ° are different. The values n1 and n2 are shown. As described above, in the state where the spiral axis is parallel to the substrate surface, the liquid crystal layer is in a state in which the regions 110 and 120 having different effective refractive indices are alternately repeated at a fine pitch. Function. Therefore, the light incident on the liquid crystal layer is diffracted by the liquid crystal layer and emitted in a direction different from the incident direction. The above phenomenon occurs not only when the spiral axis is parallel to the substrate surface but also when the spiral axis is in a direction not parallel to the normal line direction of the substrate surface.

On the other hand, when the liquid crystal layer is in the uniform state, the major axis directions of all the liquid crystal molecules in the liquid crystal layer are aligned in substantially the same direction, so that the effective refractive index of the liquid crystal layer is within the layer. The light incident on the liquid crystal layer is emitted without being diffracted. Therefore, the light incident on the liquid crystal layer is emitted in the substantially same direction as the incident direction.

Thus, the reflection type liquid crystal device of the present invention is as follows.
Black and white display and color display can be performed by switching the liquid crystal layer between the focal conic state and the uniform state.

Focusing on one dot, when the liquid crystal layer is in a uniform state, the light incident on the liquid crystal layer from the first substrate is not diffracted by the liquid crystal layer and is emitted in the same direction as the incident direction. On the liquid crystal layer side of the second substrate, a reflection type color filter having a reflection element that transmits the light incident from the same direction as the incident direction of the light incident on the first substrate is provided. Light incident on the reflective element of the mold color filter is transmitted through the reflective element regardless of its wavelength and is absorbed by a light absorber provided on the side opposite to the light incident side of the reflective element. Therefore, when the liquid crystal layer is in a uniform state, there is no light emitted to the observer side, so that black can be displayed.

Similarly, when focusing on one dot, when the liquid crystal layer is in the focal conic state, the light incident on the liquid crystal layer is diffracted by the liquid crystal layer and emitted in a direction different from the incident direction, and reflected by the reflection type color filter. It is incident on the element. Here, the reflective element of the reflective color filter enters the liquid crystal layer when the liquid crystal layer is in the focal conic state,
It is configured to reflect light of a specific wavelength diffracted by the liquid crystal layer. Therefore, when the liquid crystal layer is in the focal conic state, the light of the specific wavelength diffracted by the liquid crystal layer is reflected by the reflective element and emitted to the observer side,
The color can be displayed.

Although the above description has focused on one dot, a plurality of types of reflective elements that reflect different colored lights (lights of different wavelengths) are provided for each dot, and the liquid crystal layer is set to the focal conic state for each dot. By switching to the uniform state and displaying one pixel with a plurality of dots, monochrome display and color display are possible. For example, three types of reflective elements that reflect red light, green light, and blue light are provided for each dot, and the liquid crystal layer is switched between the focal conic state and the uniform state for each dot.
When displaying 1 pixel with 3 dots, of 3 dots,
Black display is possible by setting the liquid crystal layer of all dots to the uniform state, and color display is possible by setting the liquid crystal layer of 1 dot or 2 dots to the focal conic state, and the liquid crystal layer of all dots is focal. White display is possible by setting the conic state.

As described above, according to the reflective liquid crystal device of the present invention, display can be performed without using a polarizer that absorbs light, so that bright (high brightness) color display and white display are realized. be able to. Further, in the reflection type liquid crystal device of the present invention, since light of a specific wavelength is reflected by the reflection type color filter to perform color display, compared with the case of using a conventional pigment dispersion type color filter which is a light absorption type. It is possible to obtain a vivid color display with high color purity. On the other hand, when the liquid crystal layer is in a uniform state, light incident on the liquid crystal layer is absorbed by the light absorber and no light is emitted to the observer side, so that it is possible to obtain pure black display with low brightness. . Further, since the light incident on the liquid crystal layer is not reflected by the reflective color filter, there is no fear that the face of an observer is reflected on the display surface.

Therefore, according to the present invention, a bright display can be realized, and the contrast is excellent.
It is possible to provide a reflective liquid crystal device which is excellent in display quality and can perform monochrome display and color display.

In the reflective liquid crystal device of the present invention,
The liquid crystal layer can be switched between the focal conic state and the uniform state by configuring the liquid crystal layer with a chiral nematic liquid crystal or a cholesteric liquid crystal in which a chiral agent is added to the nematic liquid crystal. When a positive chiral nematic liquid crystal or cholesteric liquid crystal whose molecular long axis is easily polarized is used, when no voltage is applied, the liquid crystal molecules are twisted and arranged in a spiral shape, so a focal conic state can be obtained. When applied,
Since the alignment of liquid crystal molecules is changed along the vertical electric field generated between the first substrate and the second substrate, a uniform state can be obtained, and the liquid crystal layer can be easily switched between the focal conic state and the uniform state. can do.

As described above, since the liquid crystal layer can be easily switched between the focal conic state and the uniform state, it is preferable to use the positive chiral nematic liquid crystal or the cholesteric liquid crystal.
A negative chiral nematic liquid crystal or cholesteric liquid crystal in which the minor axis side is easily polarized can also be used. In this case, by appropriately designing the alignment film and electrodes, it is possible to make the uniform state when no voltage is applied and the focal conic state when voltage is applied, and to switch the liquid crystal layer between the focal conic state and the uniform state. You can

In the present specification, "when no voltage is applied" and "when voltage is applied" mean "when the voltage applied to the liquid crystal layer is less than the threshold voltage of the liquid crystal" and "when the voltage is applied to the liquid crystal layer", respectively. When the applied voltage is greater than or equal to the threshold voltage of the liquid crystal ”.

In the reflective liquid crystal device of the present invention,
When the liquid crystal layer is in the focal conic state, the liquid crystal has a pretilt angle of 20 to 85 ° and a chiral pitch of 0.1.
It is preferably 10 μm. Hereinafter, FIG.
(D) schematically shows cross-sectional views of the liquid crystal layer near the substrate cut in the direction perpendicular to the substrate surface. Based on these drawings, when the liquid crystal layer is in the focal conic state, The reason why it is preferable to set the pretilt angle to 20 to 85 ° will be described. 7, liquid crystal molecules are denoted by reference numeral 100 as in FIG. 6, and in the liquid crystal molecules 100, liquid crystal molecules whose major axis direction is horizontal to the cutting plane and vertical liquid crystal molecules are respectively , Reference numerals 100a, 100b
It shows with. In addition, the spiral axis is denoted by A and the substrate is denoted by 20.
It is indicated by 0.

When the pretilt angle of the liquid crystal is 0 °,
As shown in FIG. 7A, since the spiral axis A is substantially parallel to the normal line direction of the substrate surface, the focal conic state cannot be obtained. Further, the present inventor has found that even when the pretilt angle of the liquid crystal is more than 0 ° and less than 20 °, the pretilt angle of the liquid crystal is small and the TN (Twisted Nematic)
Mode and STN (Super Twisted Nematic) mode are displayed, the spiral axis becomes almost parallel to the normal direction of the substrate surface, and there are cases where the focal conic state cannot be obtained, and it stabilizes. It has been found that it is difficult to obtain a focal conic state.

On the other hand, when the pretilt angle of the liquid crystal is 90 °, the liquid crystal molecules 100 are twisted and aligned in a direction substantially parallel to the substrate surface, so that a focal conic state can be obtained. For example, as shown in FIG.
The liquid crystal molecules 100 are arranged by twisting from the left side in the drawing toward the right side in the drawing. However, the pretilt angle of the liquid crystal is 90
In the case of °, as shown in FIG.
0 is twisted from the back side of the paper to the front side and arranged,
The liquid crystal molecules 100 can be twisted and arranged in any direction as long as they are in a direction substantially parallel to the substrate surface. As described above, since the twisting direction of the liquid crystal molecules 100 cannot be controlled, the spiral axis A of all the liquid crystal molecules 100 can be controlled.
Is difficult to align in the desired direction. Further, the present inventor has found that the liquid crystal molecule 100 has a pretilt angle of more than 85 °.
It has been found that it is difficult to align the spiral axes A of all the liquid crystal molecules 100 in a desired direction even when the pretilt angle is less than 90, as in the case where the pretilt angle is 90 °.

On the other hand, as shown in FIG.
When the pretilt angle of the liquid crystal is 20 to 85 °,
The liquid crystal molecules 100 can be arranged in a spiral shape, and the spiral axis A can be defined in a direction substantially perpendicular to the long axis direction of the liquid crystal molecules 100 tilted by 20 to 85 ° with respect to the substrate surface. Since the spiral axes A of all the liquid crystal molecules 100 can be aligned in a desired direction, a good focal conic state can be obtained.

In order to obtain a pretilt angle of 20 to 85 °, an inorganic material such as silicon oxide is obliquely vapor-deposited on the outermost surface of the substrate on the liquid crystal layer side, and the inorganic material is tilted with respect to the substrate surface. The crystal may be grown to form the orientation film made of the inorganic oblique vapor deposition film. Thus, when the alignment film is formed by the oblique evaporation method, as shown in FIG. 7D, liquid crystal molecules near the alignment film are formed along the shape of the crystal 300 of the inorganic material forming the alignment film. 100 liquid crystal molecules are arranged.
Since the other liquid crystal molecules 100 are twisted and arranged with respect to
The spiral axes A of all the liquid crystal molecules 100 can be aligned in a desired direction.

Next, based on FIG. 6, when the liquid crystal layer is in the focal conic state, the chiral pitch of the liquid crystal is set to 0.1.
The reason why it is preferable to set the thickness to 10 μm will be described.
The chiral pitch means the distance until the liquid crystal molecules 100 are twisted by 0 to 360 °, and corresponds to the distance indicated by the symbol P in FIG. As described above, when the liquid crystal layer is in the focal conic state, the liquid crystal layer has a region 110 having a different effective refractive index.
And 120 are alternately repeated to function as a diffraction grating, but as shown in the figure, the pitch d of this diffraction grating corresponds to 1/4 of the chiral pitch P. Therefore, setting the chiral pitch of the liquid crystal to 0.1 to 10 μm means that the grating pitch d of the liquid crystal layer functioning as a diffraction grating is 2
It will be 5 nm to 2.5 μm.

The inventor of the present invention has found that when the chiral pitch P of the liquid crystal in the focal conic state is less than 0.1 μm, the grating pitch d of the liquid crystal layer functioning as a diffraction grating is the wavelength of light incident on the liquid crystal layer (380 to 780 nm). It has been found that the light incident on the liquid crystal layer may not be diffracted by the liquid crystal layer because the light becomes too small as compared with the above. In addition, the chiral pitch P of the liquid crystal in the focal conic state is 10
If it exceeds μm, the grating pitch d of the liquid crystal layer functioning as a diffraction grating becomes too large compared to the wavelength of the light incident on the liquid crystal layer, and the light incident on the liquid crystal layer may not be diffracted by the liquid crystal layer. I found it. When the light incident on the liquid crystal layer is not diffracted by the liquid crystal layer when the liquid crystal layer is in the focal conic state, even if the liquid crystal layer is switched between the focal conic state and the uniform state, the traveling direction of the light transmitted through the liquid crystal layer Cannot be displayed because they are in almost the same direction.

On the other hand, the inventors of the present invention set the chiral pitch P of the liquid crystal in the focal conic state to 0.1 to 0.1.
It has been found that when the thickness is 10 μm, when the liquid crystal layer is in the focal conic state, the light incident on the liquid crystal layer can be diffracted stably and display can be performed.

Further, it is preferable to provide an illuminating means (front light) on the light incident side of the first substrate. In this case, display can be performed even in a dark place where the brightness of external light is insufficient. Therefore, it is preferable. Further, when the illuminating means is provided on the light incident side of the first substrate, the emission direction of the light emitted from the illuminating means can be specified. Therefore, when the liquid crystal layer is in the uniform state, it is emitted from the illuminating means. It is possible to perform black display by arranging such that light that passes through the reflective element of the reflective color filter is transmitted.

In the reflective liquid crystal device of the present invention,
It is preferable that the light reflection direction of each reflection element of the reflection type color filter is set to the observation direction of the observer. In a reflective liquid crystal device provided in a portable electronic device such as a mobile phone or a portable information processing device, an observation direction of an observer is almost specified with respect to a display surface. Therefore, by setting the light reflection direction of each reflection element of the reflection type color filter to the observation direction of the observer, it is possible to increase the amount of light visually recognized by the observer when the liquid crystal layer is in the focal conic state. The brightness and contrast in color display and white display can be further improved. In the present specification, the “light reflecting direction of the reflective element” is “the traveling direction of the light reflected by the reflective element”.
Is meant.

In the reflective liquid crystal device of the present invention,
It is preferable that the liquid crystal layer can be changed stepwise between the focal conic state and the uniform state. By adopting such a configuration, gradation display is possible and full color display is realized. can do. In the reflection type liquid crystal device of the present invention, as the reflection type color filter, a reflection type hologram color filter having a hologram element as the reflection element can be exemplified. Since the hologram element has a light-condensing function, by forming the hologram element as the reflecting element, it is possible to further improve the display brightness and the contrast.

By providing the above-described reflective liquid crystal device of the present invention, bright display can be realized, and
An electronic device with excellent contrast and display quality can be provided.

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described in detail. [Reflective Liquid Crystal Device] The structure and display mechanism of the reflective liquid crystal device according to the embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an exploded schematic perspective view of the reflective liquid crystal device of this embodiment, and FIG. 2 is a schematic cross-sectional view of the reflective liquid crystal device of this embodiment. 3 and 4 are views for explaining the display mechanism of the reflective liquid crystal device of this embodiment.
FIG. 3 is a partial schematic cross-sectional view showing an enlarged view of the reflective liquid crystal device shown in FIG. 2 to 4 are cross-sectional views when the reflective liquid crystal device shown in FIG. 1 is cut in a direction perpendicular to the display surface (the outermost surface of the reflective liquid crystal device on the observer side). In the present embodiment, an active matrix reflective liquid crystal device using a TFT (Thin-Film Transistor) element as a switching element will be taken up and described. Also, in each figure,
In order to make each layer and each member recognizable in the drawing, the scale is different for each layer and each member.

As shown in FIGS. 1 and 2A, the reflection type liquid crystal device 10 of the present embodiment has an element substrate (first substrate) which is opposed to the liquid crystal layer 40 (not shown in FIG. 1). substrate)
2 and a counter substrate (second substrate) 20. As shown in FIG. 2A, among these substrates,
The element substrate 30 side is arranged so as to be the observer side.

In the reflection type liquid crystal device 10 of the present embodiment, the element substrate 30 side is the light incident side, and the light source 51 and the light emitted from the light source 51 are provided on the liquid crystal layer 40 on the observer side of the element substrate 30. A front light (illumination means) 50 (not shown in FIG. 1) is provided, which is roughly configured by a light guide plate 52 that guides light to the side. The front light 50 is used as an auxiliary illuminating means. When the outside light is sufficiently bright, the front light 50 is not turned on and the display is performed using only the outside light incident from the observer side. The light is turned on only when the brightness of the light is insufficient, and it functions as a lighting unit.

As shown in FIG. 2B, when the reflective liquid crystal device 10 of the present embodiment is provided in a portable electronic device such as a mobile phone or a portable information processing device, an observer generally uses an electronic device. In order to make the display surface of the device easy to see, the electronic device (reflective liquid crystal device 10) is tilted with respect to the ground, and the display is observed from the direction substantially normal to the display surface. In FIG. 2B, the normal line direction of the display surface of the reflective liquid crystal device 10 is indicated by the symbol H.

On the other hand, outside light specifically means light emitted from a lighting device provided on the ceiling or the like indoors, and light emitted from sunlight, street lights, etc. outdoors. However, these external lights enter the display surface of the reflective liquid crystal device 10 from a position higher than the viewer. Therefore, the incident direction L1 of the external light entering the reflective liquid crystal device 10
Is almost perpendicular to the ground, and the normal direction H of the display surface
The angle deviates from the angle θ by. When observing a reflective liquid crystal device mounted on a portable electronic device, this angle θ is
Generally, within a range of 10 to 30 °, it is almost specified by the size of the electronic device.

Then, in the present embodiment, FIG.
As shown in (a), when the front light 50 is turned on, the incident direction L2 of light incident on the liquid crystal layer 40 from the front light 50 is set to be substantially the same as the incident direction L1 of external light. There is. That is, the incident direction L2 of the light that enters the liquid crystal layer 40 from the front light 50 is set to a direction that is deviated from the normal direction H of the display surface of the reflective liquid crystal device 10 (the surface on the light incident side of the element substrate 30) by an angle θ. Has been done. The incident direction of the light incident from the front light 50 to the liquid crystal layer 50 side can be controlled by devising the shape of the light guide plate 52 of the front light 50.

As shown in FIG. 1, an element substrate 30 which constitutes the reflection type liquid crystal device 10 of the present embodiment includes a substrate body 31 having a light transmitting property and a TFT element 3 formed on the surface thereof.
2, mainly composed of the pixel electrode 33 and the like. More specifically, a large number of data lines 34 and a large number of scanning lines 35 are provided in a grid pattern on the surface of the substrate body 31 on the liquid crystal layer 40 side so as to intersect each other. A TFT element 32 is formed near the intersection of each data line 34 and each scanning line 35, and a pixel electrode 33 made of a transparent conductive material such as indium tin oxide (ITO) is provided via each TFT element 32.
Are connected. Looking at the entire surface of the element substrate 30 on the liquid crystal layer 40 side, a large number of pixel electrodes 33 are arranged in a matrix, and in the reflective liquid crystal device 10, each pixel electrode 33 and each pixel electrode 33 are arranged so as to surround each pixel electrode 33. The area where the data line 34, the scanning line 35, and the like are formed is the dot 1. In addition, as shown in FIG.
0 on the liquid crystal layer 40 side outermost surface is the liquid crystal layer 4 when no voltage is applied.
An alignment film 36 (not shown in FIG. 1) for controlling the alignment of the liquid crystal molecules in 0 is formed.

On the other hand, as shown in FIGS. 1 and 2A, the counter substrate 20 includes a substrate main body 21 and a reflective hologram color filter (reflective color filter) sequentially laminated on the liquid crystal layer 40 side surface thereof. ) 22, the common electrode 23, and the light absorber 2 formed on the opposite side of the substrate body 21 from the liquid crystal layer 40.
4 and the main components. The reflective hologram color filter 22, the common electrode 23, and the light absorber 24
Is formed on the surface of the substrate body 21 in at least the region (display region) where the pixel electrode 33 and the like are formed. In addition, the common electrode 23, like the pixel electrode 33,
It is made of a transparent conductive material such as TO. Also, FIG.
As shown in (a), an alignment film 25 (not shown in FIG. 1) for controlling the alignment of liquid crystal molecules in the liquid crystal layer 40 when no voltage is applied is provided on the outermost surface of the counter substrate 20 on the liquid crystal layer 40 side. Has been formed.

As shown in FIG. 1, the reflection type hologram color filter 22 is composed of three types of hologram elements (reflection elements) 22R, 22G and 22B and a light shielding layer 22A formed between adjacent hologram elements. ing.
Here, the hologram elements 22R, 22G, and 22B are periodically provided in a predetermined pattern corresponding to each dot 1. However, the patterns of the hologram elements 22R to 22B are not limited to the illustrated ones.

The hologram elements 22R to 22B are elements having a property of transmitting light incident from a specific direction and reflecting light of a specific wavelength incident from a specific direction. Also, the hologram elements 22R, 22G, and 22B differ only in the wavelength of the reflected light, and are respectively red light, green light, and
It is configured to reflect blue light. The hologram elements 22R and 22R will be described in detail later.
The dot 1 on which G and 22B are formed can display red (R), green (G), and blue (B), respectively, and the adjacent three dots on which these hologram elements 22R, 22G, and 22B are formed. It is possible to display one pixel. In addition, in the present embodiment, the hologram element 22R
The light reflection directions of ~ 22B are set so as to be the observation direction of the observer, that is, a direction substantially normal to the surface of the element substrate 30 on the light incident side.

The reflective liquid crystal device 10 of this embodiment is also used.
The display can be performed by switching the liquid crystal layer 40 between the focal conic state and the uniform state. In the reflective liquid crystal device 10,
The liquid crystal layer 40 is made of a positive chiral nematic liquid crystal or a cholesteric liquid crystal whose molecular long axis side is easily polarized,
When no voltage is applied, the liquid crystal molecules in the liquid crystal layer 40 are arranged to be twisted and arranged in a spiral shape. In addition, when no voltage is applied, the pretilt angle of the liquid crystal is 20 to 8
The chiral pitch is 5 ° and the pitch is 0.1 to 10 μm.

The pretilt angle of the liquid crystal when no voltage is applied is 5 ° in the conventional active matrix type liquid crystal device.
It is about 10 ° even in the conventional passive matrix type liquid crystal device of STN mode. Therefore, in the reflective liquid crystal device 10 of the present embodiment, the pretilt angle of the liquid crystal when no voltage is applied is more than double that of the conventional liquid crystal device.

In order to obtain such a high pre-tilt angle, an inorganic material such as silicon oxide is obliquely vapor-deposited on the base on which the alignment film is formed, and the inorganic material is crystal-grown in a direction inclined with respect to the substrate surface. Thus, the alignment films 25 and 36 made of the inorganic oblique vapor deposition film may be formed. In the orientation film composed of the inorganic oblique deposition film, the alignment of liquid crystal molecules when no voltage is applied can be regulated by the surface shape, but by controlling the deposition direction, the formed crystal and the substrate surface The angle can be controlled, and the pretilt angle of liquid crystal molecules when no voltage is applied can be controlled. In addition, the chiral pitch of the liquid crystal is the addition amount of the chiral agent,
It can be controlled by the surface shape of the alignment films 25 and 36.

As described above, the liquid crystal layer 40 is constituted by the chiral nematic liquid crystal or the cholesteric liquid crystal, and the pretilt angle and the chiral pitch of the liquid crystal when no voltage is applied are defined, whereby the "means for solving the problem" is obtained. As described in the section, the liquid crystal layer can be stably brought into the focal conic state when no voltage is applied. On the other hand, when a voltage is applied, between the element substrate 30 and the counter substrate 20 (the pixel electrode 33 and the common electrode 23
Since the alignment of the liquid crystal molecules is changed along the vertical electric field generated in (between), the liquid crystal layer 40 can be in a uniform state.

As described above, in the reflective liquid crystal device 10, the liquid crystal layer 40 can be switched between the focal conic state and the uniform state, and as described in the section "Means for solving the problem". When the liquid crystal layer 40 is in the focal conic state, the liquid crystal layer 40 functions as a diffraction grating, and light incident on the liquid crystal layer 40 is diffracted by the liquid crystal layer 40 and emitted in a direction different from the incident direction. When the layers are in a uniform state, light incident on the liquid crystal layer is not diffracted but is emitted in substantially the same direction as the incident direction, so that display can be performed.

The hologram elements 22R to 22B forming the hologram color filter 22 are the element substrate 30.
The light incident on the liquid crystal layer 40 in the direction substantially the same as the incident direction of the light is transmitted, and when the liquid crystal layer 40 is in the focal conic state, the light incident on the liquid crystal layer 40 and diffracted by the liquid crystal layer 40 has a specific wavelength. It is configured to reflect.

The reflection type liquid crystal device 10 of the present embodiment is configured as described above, and according to the present embodiment, it is possible to provide the reflection type liquid crystal device 10 capable of monochrome display and color display. The display mechanism of the reflective liquid crystal device 10 of the present embodiment will be described below with reference to FIGS. 3 and 4. 3 and 4 are partial schematic cross-sectional views showing enlarged regions (three dots) in which a total of three adjacent hologram elements 22R to 22B are formed in the reflective liquid crystal device 10 of the present embodiment. 3 and 4 show the liquid crystal layer 40 in the uniform state and the focal conic state, respectively. 3 and 4, the front light 50, the TF
The T element 32, the pixel electrode 33, the alignment film 36, the light shielding layer 22A of the reflective hologram color filter 22, and the like are omitted from the illustration.

As described above, in the reflection type liquid crystal device 10 of this embodiment, when the outside light is used, the front light 5 is used.
In any case where the light emitted from 0 is used, the light is incident on the element substrate 30 from a direction deviated by an angle θ from the normal line direction of the light incident side surface of the element substrate 30. In FIG. 3 and FIG. 4, the external light and the light emitted from the front light 50 are collectively denoted by L.

Further, the reflection type hologram color filter 2
Although the light-shielding layer 22A is formed between two adjacent hologram elements, the area of the light-shielding layer 22A in each dot is extremely small compared to the area of the hologram elements 22R to 22G, so the description will be given below. For simplification, it is assumed that all the light entering the reflective hologram color filter 22 from the liquid crystal layer 40 enters the hologram elements 22R to 22B. Further, in reality, refraction or the like of light occurs at the interface of each layer, and therefore the traveling direction of the light slightly shifts each time the light passes through the layer. However, in order to simplify the description, the interface of layers other than the liquid crystal layer 40 Then, let's go straight ahead.

As shown in FIG. 3, when the liquid crystal layer 40 is in a uniform state, the light L incident on the element substrate 30 is refracted at the interface between the element substrate 30 and the liquid crystal layer 40, and the liquid crystal layer 4
It goes straight in 0, is refracted again at the interface between the liquid crystal layer 40 and the counter substrate 20, and is emitted in the same direction as the incident direction. That is, both the incident angle and the outgoing angle of the light incident on the liquid crystal layer 40 are substantially equal to θ.

As described above, hologram elements 22R-2
2B is configured to transmit light that is incident in a direction substantially the same as the direction that is deviated from the normal direction of the light incident side surface of the element substrate 30 by an angle θ, so that the light that is incident on the reflective hologram color filter 22 is transmitted. Irrespective of its wavelength, the light passes through the hologram elements 22R to 22B as it is, enters the light absorber 24 formed on the opposite side of the counter substrate 20 from the light incident side, and is absorbed. As described above, when the liquid crystal layer 40 is in the uniform state, there is no light emitted to the viewer side, and thus black is displayed.

On the other hand, as shown in FIG. 4, when the liquid crystal layer 40 is in the focal conic state, since the liquid crystal layer 40 functions as a diffraction grating, the light L incident on the element substrate 30 is diffracted by the liquid crystal layer 40. At this time, when the liquid crystal layer 40 is in a uniform state, it is diffracted more than it is refracted at the interface between the element substrate 30 and the liquid crystal layer 40. Therefore, while the incident angle of light incident on the liquid crystal layer 40 is θ, the emission angle is α, which is smaller than θ. For example, the element substrate 30
When the incident angle θ of the light that is incident on is 20 °, the outgoing angle α of the light that is emitted from the liquid crystal layer 40 is 5 to 10 °.

The light diffracted by the liquid crystal layer 40 is reflected by the hologram element 22R of the reflective hologram color filter 22.
-22B. Hologram elements 22R to 22B
Reflects the red light, the green light, and the blue light that are incident from a specific direction, but the hologram elements 22R to 22B are configured to reflect the light diffracted by the liquid crystal layer 40. Of the light diffracted by 40, the red light, the green light, and the blue light are respectively hologram element 22R,
It is reflected by 22G and 22B.

The light reflection direction of the hologram elements 22R to 22B is the observation direction of the observer, that is, the element substrate 3
The light reflected by the hologram elements 22R to 22B is emitted toward the observer's side and is visually recognized because the light is set to be substantially in the normal direction to the light incident side surface of 0. That is, when viewed for each dot on which the hologram elements 22R to 22B are formed, red (R), green (G), and blue (B) are displayed, respectively.

The liquid crystal layer 4 in the focal conic state
As described in the section “Means for Solving the Problems”, 0 is a state in which regions having different effective refractive indices are repeated, so that the light reflected by the hologram elements 22R to 22B is the liquid crystal layer 40. As it passes through, it is scattered a little.
Therefore, even if the observer's observation position is slightly deviated from the direction substantially normal to the display surface, the display can be visually recognized, which is preferable. However, the hologram elements 22R to
The light reflected by 22B is not largely scattered when passing through the liquid crystal layer 40 in the focal conic state, so that the amount of light emitted in the observation direction is reduced and the brightness of the display is not likely to be reduced.

As described above, in FIGS. 3 and 4, the case where all the three dots on which the hologram elements 22R to 22B are formed are in the uniform state or the focal conic state has been described. However, the liquid crystal layer 40 is set to the uniform state for each dot. By switching to the focal conic state and displaying one pixel with three dots on which the hologram elements 22R to 22B are formed, it is possible to obtain a monochrome display and a color display.

That is, black display is possible by setting the liquid crystal layer 40 of all the dots among the three dots to the uniform state, and white display is possible by setting the liquid crystal layer 40 of all the dots to the focal conic state. Become. Further, color display can be performed by setting the liquid crystal layer 40 of 1 dot or 2 dots of the 3 dots to the focal conic state. Specifically, among the three dots, only the liquid crystal layer 40 of the dots on which the hologram elements 22R (22G, 22B) are formed is brought into the focal conic state, whereby red display (green display, blue display) becomes possible. . Further, by setting the liquid crystal layer 40 of 2 dots out of 3 dots to the focal conic state, it is possible to display a color in which two colors of red, green and blue are mixed.

Further, in the present embodiment, the liquid crystal layer 40
It is preferable that the liquid crystal layer 40 be stepwise changed between the uniform state and the focal conic state by gradually changing the voltage applied to the liquid crystal layer 40. By adopting such a configuration, gradation display is possible. Therefore, full-color display can be realized.

The reflective liquid crystal device 10 of the present embodiment can perform display as described above. According to the reflective liquid crystal device 10 of the present embodiment, display is performed without using a polarizer that absorbs light. Therefore, bright (high brightness) color display and white display can be realized.
Further, in the reflective liquid crystal device 10 of the present embodiment, since light of a specific wavelength is reflected by the reflective hologram color filter 22 to perform color display, it is compared with a conventional pigment dispersion type color filter which is a light absorbing type. Thus, a vivid color display with high color purity can be obtained.

On the other hand, when the liquid crystal layer 40 is in the uniform state, the light incident on the liquid crystal layer 40 is absorbed by the light absorber 24 and no light is emitted to the observer side, so that the brightness is low and pure black. You can get the display. In addition, since the light entering the liquid crystal layer 40 is not reflected by the reflective hologram color filter 22, there is no fear that the face of an observer will be reflected on the display surface.

Therefore, according to the present embodiment, it is possible to provide a reflective liquid crystal device 10 which can realize bright display and is excellent in contrast and display quality and capable of monochrome display and color display. it can.

Further, in this embodiment, the pretilt angle of the liquid crystal is set to 20 to 85 ° and the chiral pitch is set to 0.1 to 10 μm when no voltage is applied. Therefore, it will be described in the section “Means for solving the problems”. As described above, a stable focal conic state can be obtained when no voltage is applied,
The display can be performed stably.

Further, in this embodiment, the liquid crystal layer 40 is composed of the positive type chiral nematic liquid crystal or the cholesteric liquid crystal in which the long axis side of the molecule is easily polarized. Therefore, when no voltage is applied, the liquid crystal molecules are spirally twisted and aligned. Then, a focal conic state can be obtained, and when the voltage is applied, the alignment of liquid crystal molecules can be changed so as to follow the vertical electric field generated between the element substrate 30 and the counter substrate 20, and a uniform state can be obtained. The 40 can be easily switched between the focal conic state and the uniform state.

However, the present embodiment is not limited to the case of using the positive type liquid crystal, and a negative type chiral nematic liquid crystal or cholesteric liquid crystal in which the minor axis side of the molecule is easily polarized can be used. In this case, by appropriately designing the alignment film, the electrodes, and the like, the uniform state can be obtained when no voltage is applied and the focal conic state can be obtained when a voltage is applied, and the focal conic state and the uniform state can be switched.

Further, in the present embodiment, the front light 50 is provided on the light incident side of the element substrate 30, but the present invention is not limited to this, and the front light 50 is not provided, and only the external light is provided. It may be configured to display using. However, when the front light 50 is provided as in the present embodiment, the display can be visually recognized even in a dark place, which is preferable. It should be noted that when the front light 50 is provided, the power consumption becomes larger than that when the front light 50 is not provided.
Is turned on only when the brightness of external light is insufficient, and in other cases, the display is performed using only external light, so compared to a transmissive liquid crystal device that needs to always turn on the backlight, Power consumption is extremely low.

In this embodiment, the element substrate 30 side is the light incident side (observer side), but the present invention is not limited to this, and the counter substrate 20 side may be the light incident side. . In this case, the reflective hologram color filter 22 is formed on the surface of the element substrate 30 arranged on the side opposite to the light incident side on the liquid crystal layer 40 side, and the TFT element 32,
The pixel electrode 33 and the like may be formed. However, as in the present embodiment, it is preferable that the element substrate 30 is on the light incident side. In this case, the TFT element 32, the pixel electrode 33, etc. can be directly formed on the substrate body 31, and the reflection can be achieved. Since it is sufficient to form only the common electrode 23 that does not require patterning on the type hologram color filter 22,
The manufacturing process can be simplified.

Further, in the present embodiment, the common electrode 2 is provided on the liquid crystal layer 40 side of the reflective hologram color filter 22.
However, the present invention is not limited to this, and the same effect as the present embodiment can be obtained even if the reflective hologram color filter 22 is formed on the liquid crystal layer 40 side of the common electrode 23. You can

Further, in this embodiment, the light absorber 2
4 is formed on the side of the counter substrate 20 opposite to the light incident side of the substrate body 21, but the present invention is not limited to this.
The light absorber 24 may be provided at any position as long as it is on the side opposite to the light incident side of the reflective hologram color filter 22. However, when the light absorber 24 is formed on the side opposite to the light incident side of the substrate body 21 as in the present embodiment, the light absorber 24 may be finally attached after the liquid crystal panel is manufactured. Therefore, the manufacturing process can be simplified. However, in the case of such a configuration, when the liquid crystal layer 40 is in the uniform state, the light transmitted through the reflective hologram color filter 22 is at the interface between the reflective hologram color filter 22 and the substrate body 21, or the substrate body. There is a possibility that the light will be reflected at the interface between the light absorber 21 and the light absorber 24, returned to the viewer side without being absorbed by the light absorber 24, and the brightness of black display will be increased. Therefore, if there is such a fear,
It is preferable to provide the light absorber 24 directly below the reflective hologram color filter 22.

In this embodiment, the reflection hologram color filter 22 is formed as the color filter. However, the present invention is not limited to this, and the light incident from a specific direction is transmitted, A color filter having any structure may be formed as long as it is a reflective color filter having a plurality of types of reflective elements having a function of reflecting light of a specific wavelength incident from a specific direction. The reflective hologram color filter 2 described in this embodiment is used.
As a reflective color filter other than 2, a reflective color filter having a reflective element made of cholesteric liquid crystal having selective reflectivity can be exemplified. However, since the hologram element has a light condensing function, it is preferable to form the hologram element as the reflecting element as in the present embodiment because the display brightness and contrast can be further improved.

Further, in the present embodiment, the active matrix type reflective liquid crystal device 10 using the TFT element as the switching element has been described, but the present invention is not limited to this, and TFD (Thin-Thin- Film Diod
e) The present invention can be applied to any type of reflective liquid crystal device such as an active matrix type or a passive matrix type using an element as a switching element.

[Electronic Equipment] Next, specific examples of electronic equipment provided with the reflective liquid crystal device 10 according to the above-described embodiment of the present invention will be described. FIG. 5A is a perspective view showing an example of a mobile phone. In FIG. 5A, reference numeral 500 denotes a mobile phone main body, and 501 denotes a liquid crystal display unit including the reflective liquid crystal device 10. FIG. 5B is a perspective view showing an example of a portable information processing device such as a word processor and a personal computer. In FIG. 5B, 600 is an information processing device,
Reference numeral 601 denotes an input unit such as a keyboard, 603 denotes an information processing main body, and 602 denotes a liquid crystal display unit including the reflective liquid crystal device 10. FIG. 5C is a perspective view showing an example of a wrist watch type electronic device. In FIG. 5C, 70
Reference numeral 0 denotes a watch body, and 701 denotes the reflective liquid crystal device 1 described above.
0 shows a liquid crystal display section with 0. FIG. 5 (a)-
Since the electronic device shown in (c) includes the reflective liquid crystal device according to the above-described embodiment, it is possible to realize a bright display, excellent contrast, and excellent display quality.

[0075]

EXAMPLES Next, examples according to the present invention and conventional examples will be described. (Example 1) By changing the surface shape of the alignment film and the material of the alignment film, the pretilt angle of the liquid crystal when no voltage is applied is set to 0 to 0.
An active matrix reflective liquid crystal device using a TFT element was manufactured in the same manner as in the above-described embodiment under the same conditions except that the change was made within the range of 90 °. However, no front light was provided. Further, a liquid crystal layer was constituted by a chiral nematic liquid crystal, the cell thickness was 7.5 μm, and the chiral pitch of the liquid crystal when no voltage was applied was 7.0 μm. Five reflective liquid crystal devices of the same type were manufactured, and the liquid crystal layer when no voltage was applied was observed with a microscope from the light incident side to determine whether a focal conic state occurred and whether the direction of the spiral axis could be controlled. The evaluation was performed based on the following criteria.

When the focal conic state occurs, regions having different effective refractive indices are alternately repeated, so that it is observed that dark-colored portions and light-colored portions are repeated in stripes. . The direction of the spiral axis corresponds to a direction substantially perpendicular to the extending direction of the dark and light portions. Further, in this example, a liquid crystal layer in which at least a focal conic state was generated was evaluated as “a focal conic state was generated”.

<Presence or Absence of Focal Conic State> Criteria O: Focal conic state occurred in all reflective liquid crystal devices. Δ: Some had a focal conic state, but some did not. X: The focal conic state did not occur in all reflective liquid crystal devices.

<Possibility of Controlling Direction of Helical Axis> Judgment Criteria ◯: The entire liquid crystal layer of each reflection type liquid crystal device,
The spiral axes were aligned in substantially the same direction, and the liquid crystal spiral axes of all reflective liquid crystal devices were aligned in the same direction. X: A plurality of focal conic states having different spiral axis directions were generated in the liquid crystal layer of each reflective liquid crystal device. Alternatively, the spiral axes of the liquid crystal layers of the individual reflective liquid crystal devices are aligned in substantially the same direction, but the spiral axes of the liquid crystals of all the reflective liquid crystal devices cannot be aligned.

<Results> Table 1 shows the evaluation results obtained in Example 1. As shown in Table 1, when the pretilt angle of the liquid crystal was 0 °, the focal conic state did not occur in all reflective liquid crystal devices. Also, when the pretilt angle of the liquid crystal was 5 °, some of the focal conic states occurred, but some did not.
It was not possible to stably generate the focal conic state. On the other hand, the pretilt angle of the liquid crystal is 2
At 0 to 90 °, the focal conic state occurred at least partially in all the reflective liquid crystal devices.

As described above, the pretilt angle of the liquid crystal is 5 to
At 90 °, a focal conic state could be obtained at least partially, but the pretilt angle of the liquid crystal was 5 °.
Alternatively, at 90 °, the directions of the spiral axes cannot be controlled in substantially the same direction, and the pretilt angle of the liquid crystal is 20 to 85.
By setting the angle to °, it is possible to align the spiral axes in substantially the same direction over the entire liquid crystal layer of each reflective liquid crystal device, and at the same time, set the spiral axes of the liquid crystal in all reflective liquid crystal devices in substantially the same direction. And the direction of the spiral axis could be well controlled. From the above results, it was found that by setting the pretilt angle of the liquid crystal to 20 to 85 °, the focal conic state can be stably generated and the spiral axis of the liquid crystal can be well controlled.

[0081]

[Table 1]

Example 2 The same TFT as in the above-described embodiment was used under the same conditions except that the chiral pitch of the liquid crystal when no voltage was applied was changed in the range of 0.05 to 15.0 μm.
An active matrix reflective liquid crystal device using the device was manufactured. However, no front light was provided. In addition, the liquid crystal layer is composed of chiral nematic liquid crystal,
The cell thickness was 7.5 μm, and the pretilt angle of the liquid crystal when no voltage was applied was 70 °. The obtained reflective liquid crystal device was irradiated with light from a direction deviated from the normal direction of the substrate surface of the element substrate by 20 °, and the presence or absence of the diffraction phenomenon was evaluated based on the following criteria.

<Presence or Absence of Diffraction Phenomenon> Judgment Criteria ◯: The incident angle (20 °) of the light incident on the element substrate and the emission angle of the light emitted from the counter substrate side are not equal, and the diffraction phenomenon occurs. did. X: The incident angle (20 °) of the light incident on the element substrate and the emission angle of the light emitted from the counter substrate side were substantially equal to each other, and the diffraction phenomenon did not occur. The deviation between the incident angle (20 °) of the light incident on the element substrate and the emission angle of the light emitted from the counter substrate side is 2.0 °.
When it is less than, it is considered to be almost equal, and when it is more than that, it is not considered to be equal.

<Results> Table 2 shows the evaluation results obtained in Example 2. As shown in Table 2, no diffraction phenomenon occurs when the liquid crystal chiral pitch is 0.05 μm and 15.0 μm when no voltage is applied, and the liquid crystal chiral pitch when no voltage is applied is 0.1 to 10.0 μm. By
It has been found that a diffraction phenomenon can be generated.

[0085]

[Table 2]

Example 3 The same TF as in the above embodiment
An active matrix reflective liquid crystal device using a T element was manufactured. However, no front light was provided.
The liquid crystal layer is composed of chiral nematic liquid crystal, and the pretilt angle of the liquid crystal is 60 when no voltage is applied.
And the chiral pitch was 4.0 μm.

(Conventional Example) A conventional pigment dispersion type color filter, a light reflecting plate formed on the side opposite to the light incident side of the color filter, and a polarizer formed on the outer side of the substrate on the light incident side. An active matrix reflection type liquid crystal device using a conventional TFT element, which is provided with a retardation plate, was manufactured.

<Evaluation and Results> A light source was installed in a direction displaced by 20 ° from the normal line direction of the display surface of the reflection type liquid crystal device obtained in the above Example 3, and the display brightness and contrast of the reflection type liquid crystal device were adjusted. When measured, the brightness is 80%,
The contrast was 30, and vivid color display could be obtained. On the other hand, when the brightness and contrast of the reflection type liquid crystal device obtained in the conventional example were measured in the same manner, the brightness was 30% and the contrast was 20. The brightness indicates a relative value when the brightness of the standard white plate is 100%. As described above, according to the present invention, the brightness can be more than doubled as compared with the conventional reflective liquid crystal device using the polarizer, high contrast can be obtained, and vivid color display can be achieved. It turns out that you can get.

[0089]

As described above in detail, according to the present invention, the light incident from a specific direction is transmitted to the liquid crystal layer side of the substrate located on the side opposite to the light incident side and is incident from the specific direction. In addition to providing a reflective color filter that is equipped with multiple types of reflective elements that reflect light of the specified wavelength, a light absorber is formed on the opposite side of the reflective color filter from the light incident side, and the liquid crystal layer is in a uniform state. Since the configuration is adopted in which the display is performed by switching to the focal conic state, it is possible to realize a bright display, and it is possible to provide a reflective liquid crystal device having excellent contrast and excellent display quality. In addition, by providing the reflective liquid crystal device of the present invention, it is possible to provide an electronic device that can realize a bright display and has excellent contrast and display quality.

[Brief description of drawings]

FIG. 1 is an exploded schematic perspective view of a reflective liquid crystal device according to an embodiment of the present invention.

2A and 2B are schematic cross-sectional views of a reflective liquid crystal device according to an embodiment of the present invention.

FIG. 3 is a diagram for explaining a display mechanism of a reflective liquid crystal device according to an embodiment of the present invention.

FIG. 4 is a diagram for explaining a display mechanism of the reflective liquid crystal device according to the embodiment of the present invention.

5A is a diagram showing an example of a mobile phone provided with the reflective liquid crystal device of the above embodiment, and FIG. 5B is a portable device provided with the reflective liquid crystal device of the above embodiment. FIG. 5C is a diagram showing an example of the information processing device, and FIG. 5C is a diagram showing an example of a wristwatch type electronic device including the reflection type liquid crystal device of the embodiment.

FIG. 6 is a diagram schematically showing a plan view of a liquid crystal layer in a focal conic state when the spiral axis is parallel to the substrate surface, as seen from the light incident side.

7 (a) to 7 (d) show that the liquid crystal layer has a pretilt angle of 20 to 8 when the liquid crystal layer is in the focal conic state.
It is a figure for demonstrating the reason why it is suitable to set it as 5 degrees.

[Explanation of symbols]

10 Reflective Liquid Crystal Device 30 Element Substrate (First Substrate) 20 Counter Substrate (Second Substrate) 21, 31 Substrate Body 22 Reflective Hologram Color Filter (Reflective Color Filter) 22R, 22G, 22B Hologram Element (Reflective Element) ) 22A light-shielding layer 24 light absorber 40 liquid crystal layers 25 and 36 alignment film 1 dot 50 front light (illuminating means)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G02B 5/32 G02B 5/32 F term (reference) 2H042 AA09 AA26 2H048 BA04 BA64 BB02 BB10 BB44 2H049 AA02 AA06 AA12 AA25 AA33 AA60 AA61 AA65 CA01 CA05 CA08 CA09 CA15 CA22 2H091 FA02Y FA14Y FA19Y FA34Z KA03 KA05 LA17

Claims (8)

[Claims] 1. A reflection type liquid crystal device comprising a first substrate and a second substrate which are arranged to face each other, and a liquid crystal layer sandwiched between the pair of substrates, wherein the liquid crystal layer is in a focal conic state and a uniform state. The first substrate side is the light incident side, and the liquid crystal layer side of the second substrate is substantially the same as the incident direction of the light incident on the first substrate. The light incident from the direction is transmitted, and when the liquid crystal layer is in the focal conic state,
A reflective color that includes a plurality of types of reflective elements that reflect light of a specific wavelength that is incident on the liquid crystal layer and diffracted by the liquid crystal layer, and different types of reflective elements reflect light of different wavelengths. A reflective liquid crystal device, wherein a filter is formed, and a light absorber is formed on a side opposite to a light incident side of the reflective color filter. 2. The reflective liquid crystal device according to claim 1, wherein the liquid crystal layer is made of chiral nematic liquid crystal or cholesteric liquid crystal. 3. The liquid crystal layer according to claim 1, wherein the liquid crystal layer has a pretilt angle of 20 to 85 ° and a chiral pitch of 0.1 to 10 μm when the liquid crystal layer is in the focal conic state. Reflective liquid crystal device. 4. The reflection according to any one of claims 1 to 3, further comprising illumination means for emitting light in a specific direction on a light incident side of the first substrate. Type liquid crystal device. 5. The light reflection direction of each reflection element of the reflection type color filter is set to an observation direction of an observer.
A reflective liquid crystal device according to item. 6. The liquid crystal layer according to claim 1, wherein the liquid crystal layer can be changed stepwise between a focal conic state and a uniform state. Reflective liquid crystal device. 7. The reflection according to claim 1, wherein the reflection-type color filter is a reflection-type hologram color filter including a hologram element as the reflection element. Type liquid crystal device. 8. Any one of claims 1 to 7
An electronic device comprising the reflective liquid crystal device according to the item 1.