JP2003222856A - Reflector, liquid crystal display device and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reflecttor provided with cholesteric liquid crystals having a configuration for realizing film thinning, and to provide a transflective liquid crystal display device provided with the reflector. <P>SOLUTION: In a transflective layer 18, respective areas 18R, 18G and 18B for respective pitches are formed within the plane of 1 dot and the color filters 30R, 30G and 30B of respective colors are formed for the respective dots to constitute one pixel. Thus, the transflective layer 18 can be formed into a thin layer and white light can be reflected by the color mixture of the reflected light of the respective areas 18R, 18G and 18B for the respective pitches within 1 dot. Also, color light to be the complementary color of the respective colors can be transmitted in the respective areas 18R, 18G and 18B for the respective pitches and the white light can be transmitted within 1 dot by the color mixture as well. Thus, on the basis of the reflected light and transmitted light close to white, color display is performed for each pixel through a color filter layer 30. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflector, a liquid crystal display device and an electronic apparatus, and more particularly to a reflector having a cholesteric liquid crystal layer, and a liquid crystal display device having the reflector.
In addition, the present invention relates to an electronic device including the liquid crystal display device.

[0002]

2. Description of the Related Art In recent years, cholesteric reflectors using cholesteric liquid crystals have been proposed. Cholesteric liquid crystals have a structure in which the liquid crystal molecules have a periodic spiral structure with a constant pitch, and have the property of selectively reflecting light of a wavelength that matches the pitch of this spiral and transmitting other light. There is. Therefore, by using a reflection plate including such a cholesteric liquid crystal, a semi-transmissive reflection type liquid crystal display device that selectively reflects light of a specific wavelength and transmits other light is provided. Is possible.

[0003]

In a reflector using such a cholesteric liquid crystal, a cholesteric reflector which has a cholesteric liquid crystal layer having a different pitch and is capable of a reflective display close to white with little coloring in the visible light region. Is getting Therefore, the layer thickness of the cholesteric liquid crystal layer is 1
When the thickness of the liquid crystal layer becomes as thick as about 0 μm, and it is difficult to uniformly control the thickness (about 5 μm) of the liquid crystal layer when the reflector is formed on the inner surface of the device as a transflective display element of the liquid crystal display device as described above. was there. When the thickness of the liquid crystal layer is not uniform in this way, display defects such as reduction in contrast may occur.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a reflection plate including a cholesteric liquid crystal having a structure for realizing thinning, and further, An object of the present invention is to provide a semi-transmissive reflection type liquid crystal display device including the reflection plate, and an electronic device including the liquid crystal display device.

[0005]

In order to achieve the above object, the reflector of the present invention is a reflector including a cholesteric liquid crystal layer and capable of reflecting colored light having a wavelength corresponding to the helical pitch of the cholesteric liquid crystal. Thus, the cholesteric liquid crystal layer includes in the plane a plurality of pitch-based regions having different helical pitches of the liquid crystal molecules, and the plurality of pitch-based regions are provided with different colored lights of different wavelengths according to the respective helical pitches. It is characterized by being reflected. In this case, since a plurality of pitch-based areas are supposed to reflect color light of different wavelengths corresponding to the respective spiral pitches for each area, each R corresponding to the three primary colors of light depending on the spiral pitch,
The G and B color lights can be reflected and the complementary colors thereof can be transmitted, and the reflection plate of the present invention can realize a semi-transmissive reflective display with less coloring that is close to white. Further, in the cholesteric liquid crystal layer, since a plurality of pitch-based regions are formed in a plane, it is possible to provide a reflector with one cholesteric liquid crystal layer without stacking the pitch-based regions. Therefore, according to the reflection plate of the present invention, it is possible to provide a reflection plate for semi-transmissive reflection display with a thin film, which is suitable for application to an electro-optical device that is desired to be downsized. Further, for example, when the reflection plate having the above-mentioned configuration is applied to a liquid crystal display device as a semi-transmissive reflection display element, the thickness of the liquid crystal layer as an electro-optical element can be made uniform. In the present invention, for example, when the reflection spectrum is measured for each position in the plane direction of the cholesteric liquid crystal layer, the position where the reflection has a minimum value, or the position where the change rate of the reflection is discontinuous is defined as a pitch-based region. It can be a boundary.

The cholesteric liquid crystal layer may reflect a part of circularly polarized light having a predetermined rotation direction and transmit a part thereof. That is, since the cholesteric liquid crystal layer reflects color light having a wavelength corresponding to the spiral pitch and transmits its complementary color, the reflector of the present invention functions as a semi-transmissive reflector. .

The plurality of pitch-based areas may include primary color reflection pitch-based areas capable of reflecting any of the three primary colors of light for each color. That is, a plurality of pitch-based areas, a red reflection pitch-based area capable of reflecting red, a green reflection pitch-based area capable of reflecting green, and a blue reflection pitch capable of reflecting blue. It may be configured to include another area. With such a configuration, a semi-transmissive reflective display with a little color and a nearly white color is realized with a thin film reflector. The spiral pitch is about 600 to 650 nm (the maximum reflection wavelength is provided in the vicinity of this wavelength. The same applies hereinafter) in the red reflection pitch-based region, and the spiral pitch is about 550 n in the green reflection pitch-based region.
The spiral pitch is about 400 to 500 nm in the m and blue reflection pitch regions. Here, when such a reflector is used as a color filter for a display device,
Realizing a color filter in which one dot is formed of at least 3 dots, and each dot is composed of a red reflection pitch-specific area, a green reflection pitch-specific area, and a blue reflection pitch-specific area (each primary color reflection pitch-specific area). can do.

On the other hand, the plurality of pitch-based areas serve as a selected-color reflection pitch-based area capable of reflecting any color selected from the three primary colors of light and a complementary color of the selected color. It is possible to include a complementary color reflection pitch-based region capable of reflecting colors. That is, a plurality of pitch-based areas reflect a selected color reflection pitch-based area capable of reflecting one color selected from red, green, and blue, and a color that is a complementary color of the selected color. It is possible to include a complementary color reflection pitch area. In this case as well, a semi-transmissive reflective display that is close to white with little coloring is realized by the thin film reflector. In addition, as a mode of forming the complementary color reflection pitch region, in addition to a mode of forming by a cholesteric liquid crystal layer having a spiral pitch corresponding to the wavelength of the complementary color, two types of spirals corresponding to two primary colors different from the above selected color An example is a mode in which cholesteric liquid crystal layers having a pitch are laminated and formed.

Next, the liquid crystal display device of the present invention is a liquid crystal in which a liquid crystal layer (also referred to as a phase modulation liquid crystal layer) is sandwiched between an upper substrate and a lower substrate which are translucent substrates and are arranged to face each other. A liquid crystal display device having a cell, wherein upper substrate side circularly polarized light incidence means for making circularly polarized light incident on the liquid crystal layer from the upper substrate side, and circularly polarized light in the same rotation direction as circularly polarized light from the lower substrate side to the upper substrate side. A lower substrate side circularly polarized light incident means for making polarized light incident and an illuminating device for making light incident on the liquid crystal cell from the lower substrate side are provided, and the liquid crystal layer is in a selective electric field applied state or a non-selective electric field applied state. Inverts the polarity of circularly polarized light that has entered in one state and does not invert the polarity in the other state, and a semi-transmissive reflective layer having the above-described reflective plate is provided on the inner surface side of the lower substrate. It is characterized by

According to such a display device, the external light incident from the upper substrate side in the circularly polarized state by the upper substrate side circularly polarized light incident means is converted into circularly polarized light in either the left or right rotation direction in the phase modulation liquid crystal layer. Modulated light, of which circularly polarized light in a specific rotation direction (for example, right) is reflected by the semi-transmissive reflective layer and provided for display. On the other hand, the illumination light incident from the lower substrate side is incident in a circularly polarized state by the lower substrate side circularly polarized light incident means, of which a circle of a specific rotation direction (for example, the left (a rotation direction different from the above-mentioned reflected rotation direction)). The polarized light is transmitted by the semi-transmissive reflective layer and provided for display. Further, in the present invention, since the reflecting plate having the above-mentioned configuration is adopted as the semi-transmissive reflective layer, the semi-transmissive reflective layer can realize a display close to white with little coloring, and as described above. Since the cholesteric liquid crystal layer is formed of a thin film without being laminated, the entire device can be made thin, and in particular, the phase modulation liquid crystal layer of It is possible to make the thickness more uniform. In the present specification, a liquid crystal display device that performs display based on such transmission and reflection may be referred to as a “semi-transmissive reflection type” liquid crystal display device, and unless otherwise specified, In the specification, the surface of the substrate on the liquid crystal side is called the inner surface, and the surface on the opposite side is called the outer surface.

Specifically, the semi-transmissive reflective layer includes, in a plane, a plurality of pitch-based regions partitioned within each dot by the helical pitch of the liquid crystal molecules. It is possible to make it possible to reflect colored light of different wavelengths according to the spiral pitch for each region. In this case, in the semi-transmissive reflective layer, a plurality of pitch-based regions are assumed to reflect colored light of different wavelengths corresponding to the respective spiral pitches in each region. The corresponding R, G, and B color lights can be reflected, and a semi-transmissive reflective display that is closer to white can be realized. As a more specific configuration, each color may include a region for each primary color reflection pitch capable of reflecting any of the three primary colors of light in the above-mentioned one dot. In this case, at least 3 dots are formed in one pixel in the semi-transmissive reflection layer, and each dot is formed from a red reflection pitch-based area, a green reflection pitch-based area, and a blue reflection pitch-based area (each primary color reflection pitch-based area). Composed.

The primary color reflection pitch regions may be formed to have substantially the same area. In this case, since each primary color reflection pitch area having the same area area for each of the three primary colors is provided within one dot, it is possible to display each dot closer to white, and in each primary color reflection pitch area The display ratio of the reflective display and the transmissive display is approximately 1: 2 in each region, and the area is the same in each region.
In the liquid crystal display device, (reflective display: transmissive display) can substantially realize a display of (1: 2). In this case, the display ratio of reflection and transmission of about 1: 2 means that about 1/3 of the amount of light incident on the semi-transmissive reflection layer is reflected and about 2/3 is transmitted. I mean.

Further, it is possible to maximize the area of the area for each green color reflection pitch corresponding to the green color among the areas for each primary color reflection pitch. In this case, the reflectance of green becomes relatively large, and green has the highest luminosity, so that the reflectance of the liquid crystal display device becomes relatively large. Therefore,
It is possible to provide a display device that emphasizes reflective display. On the other hand, when the area of the green reflection pitch-based region corresponding to the green color in each primary color reflection pitch-based region is minimized, it is possible to provide a display device that emphasizes transmissive display.

Further, within one dot, a selected color reflection area capable of reflecting any color selected from the three primary colors of light and a color complementary to the selected color are reflected. And a complementary color reflection region capable of forming the same can be formed. In this case as well, the semi-transmissive reflection display closer to white can be performed by the selected color and its complementary color. The selective reflection area and the complementary color reflection area may be formed to have substantially the same area. In this case, (reflective display: transmissive display) is approximately (1: 2) in the selective reflective region, while color light other than the selected color is reflected in the complementary color reflective region (reflective display: transmissive display). 2: 1), and assuming that the areas are the same in each region, it is possible to realize a display of (reflective display: transmissive display) of approximately (1: 1) in the liquid crystal display device. As described above, in the liquid crystal display device of the present invention, it is possible to arbitrarily set the display ratio of transmission and reflection based on each area of the pitch-based regions in the semi-transmissive reflection layer.

As a method of forming a plurality of liquid crystal molecules having different spiral pitches for each dot as described above, that is, a method of forming pitch-based regions, there is, for example, the following method. First, a cholesteric liquid crystal layer is uniformly applied to a predetermined substrate surface, and this is irradiated with ultraviolet rays. Here, if exposure is performed with an intensity distribution such that the intensity of ultraviolet rays in the dots is different, the helical pitch of the liquid crystal molecules will be different depending on the intensity (photoisomerization reaction), and the pitch will be divided for each pitch of the liquid crystal molecules. A cholesteric liquid crystal layer including another region is formed. In addition, instead of UV intensity,
It is possible to change the helical pitch of liquid crystal molecules by giving ultraviolet rays wavelength, heat, etc. to each dot. Here, each of the plurality of pitch-based regions may be formed in a rectangular shape, and in this case, the efficiency is improved during the exposure, and the area of each region is easily set, That is, it becomes easy to arbitrarily set the display ratio of transmission and reflection.

On the other hand, a color filter layer having a plurality of dye layers each containing a pigment of a different color may be formed on the inner surface side of the semi-transmissive reflective layer. In this case, since the light close to white reflected or transmitted by the semi-transmissive reflective layer passes through the color filter layer, the liquid crystal display device can perform color display.

Next, the electronic equipment of the present invention is characterized by including the liquid crystal display device having the above-mentioned configuration. According to this configuration, it is possible to provide a thin electronic device, while providing an electronic device in which the display ratio of transmission and reflection can be easily set arbitrarily.

[0018]

DETAILED DESCRIPTION OF THE INVENTION [Liquid Crystal Display Device] A first embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a partial cross-sectional structure of the liquid crystal display device of the present embodiment, and in this case, it is an example of a passive matrix type transflective color liquid crystal display device. In all of the following drawings, in order to make the drawings easy to see, the film thicknesses, the dimensional ratios, and the like of the respective constituent elements are appropriately changed.

The liquid crystal display device 10 of this embodiment is shown in FIG.
As shown in, the liquid crystal cell 11 and the backlight 12 (illumination device) are provided. In the liquid crystal cell 11, a lower substrate 13 and an upper substrate 14 are arranged to face each other with a sealing material (not shown) interposed therebetween, and an STN (Super Twisted Nematic) is provided in a space surrounded by the upper substrate 14, the lower substrate 13 and the sealing material. A liquid crystal layer (liquid crystal layer for phase modulation) 16 made of liquid crystal is enclosed, and the backlight 12 is arranged on the rear surface side of the liquid crystal cell 11 (outer surface side of the lower substrate 13).

The lower substrate 13 and the upper substrate 14 are mainly composed of a translucent material such as glass or plastic, and are on the outer surface side of the lower substrate 13 (on the side opposite to where the liquid crystal layer 16 is formed). Includes a retardation plate (1/4 wavelength plate) 27,
The lower polarizing plate 28 is provided in this order from the lower substrate 13. On the other hand, also on the outer surface side of the upper substrate 14 (on the side opposite to where the liquid crystal layer 16 is formed), a retardation plate (1/4 wavelength plate)
35 and an upper polarizing plate 36 are provided in this order from the upper substrate 14.

A semi-transmissive reflective layer 18 having a cholesteric liquid crystal layer is provided on the inner surface side (liquid crystal layer 16 side) of the lower substrate 13, and an R layer is provided on the semi-transmissive reflective layer 18 as an upper layer.
(Red), G (green), B (blue) dye layers 30R, 30
A color filter layer 30 in which G and 30B are repeatedly formed in the substrate surface direction is provided, and a flat surface for flattening a step formed by the semi-transmissive reflective layer 18 or the color filter layer 30 (dye layer) is provided thereon. A chemical film (overcoat) 31 is laminated. Then, on the flattening film 31, stripe-shaped signal electrodes 25 made of a transparent conductive film such as ITO extend in a direction perpendicular to the paper surface. On the other hand, on the inner surface side (the liquid crystal layer 16 side) of the upper substrate 14, stripe-shaped scanning electrodes 32 made of a transparent conductive film such as ITO extend in the lateral direction in the drawing. The backlight 12 includes a light source 37, a reflection plate 38, and a light guide plate 39, and the light guide plate 3
On the lower surface side of 9 (the side opposite to the liquid crystal cell 11), the light guide plate 39
A reflection plate 40 is provided for emitting light passing through the liquid crystal cell 11 toward the liquid crystal cell 11.

The upper polarizing plate 36 transmits only linearly polarized light in one direction (horizontal direction in the present embodiment), and the phase difference plate 3
Reference numeral 5 converts the linearly polarized light transmitted through the upper polarizing plate 36 into circularly polarized light. Therefore, the upper polarizing plate 36 and the phase difference plate 35 function as an upper substrate side circularly polarized light incident means. The lower polarizing plate 28 transmits only linearly polarized light in one direction (horizontal direction in the present embodiment), and the phase difference plate 27 converts the linearly polarized light transmitted through the lower polarizing plate 28 into circularly polarized light. Therefore, the lower polarizing plate 28 and the phase difference plate 27 function as a lower substrate side circularly polarized light incident means.

In the liquid crystal layer 16, a voltage is applied between the scanning electrode 25 and the signal electrode 32 (when a selection electric field is applied).
In the paper, the paper is oriented in the vertical direction of the paper surface (vertical direction), and is aligned in the horizontal direction (horizontal direction) of the paper surface when no voltage is applied (when no selective electric field is applied). Note that "when no applied electric field is applied" and "when applied electric field is selected" refer to "when the applied voltage to the liquid crystal layer is less than the threshold voltage of the liquid crystal" and "when the applied voltage to the liquid crystal layer is When the voltage is equal to or higher than the threshold voltage ”. In such a liquid crystal layer 16, it is possible to modulate the phase of incident light according to application of a selective electric field. That is, in the present embodiment, circularly polarized light that is incident when a selective electric field is applied is passed through as circularly polarized light that has the same rotation as when incident, without modulating its phase,
It is possible to modulate the phase of circularly polarized light that has entered when no selective electric field is applied, convert it into circularly polarized light that has a reverse rotation to that when incident, and allow it to pass.

Next, the semi-transmissive reflective layer 18 having a cholesteric liquid crystal layer is configured to transmit a predetermined amount of light out of circularly polarized light in a specific rotation direction and reflect the remaining amount of light. In the present embodiment, about 67% of right-handed circularly polarized light is transmitted and about 33% is reflected (ratio of transmission and reflection is approximately 2: 1), and left-handed circularly polarized light is transmitted 100%. It is said that. This is based on the fact that the cholesteric liquid crystal reflects color light having a wavelength corresponding to the helical pitch, and the cholesteric liquid crystal layer is divided into a plurality of helical pitches of the liquid crystal molecules as shown in FIG.

FIG. 2 shows the semi-transmissive reflective layer 18 of FIG.
As viewed from the rotated direction, the area includes a red reflection pitch area 18R, a green reflection pitch area 18G, and a blue reflection pitch area 18B in a plane, and the plurality of pitch areas are provided for each area. In addition, it is configured as a reflection plate that reflects color light of different wavelengths depending on the spiral pitch. Specifically, the cholesteric liquid crystal having a reflection maximum at a spiral pitch of about 600 nm is provided in the red reflection pitch-specific region 18R, the cholesteric liquid crystal has a reflection maximum at about 550 nm in the green reflection pitch-specific region 18G, and about 450 nm in the blue reflection pitch-specific region 18B. It is composed of cholesteric liquid crystal, and color light of that wavelength is reflected in each region.

Further, FIG. 3 is a plan view of the color filter layer 30 and the semi-transmissive reflective layer 18, wherein the front side of the paper is the color filter layer 30 and the rear side of the paper is the semi-transmissive reflective layer 18.
Is. In the color filter layer 30, the black matrix BM is formed at the boundary of each color. In this way, in the semi-transmissive reflective layer 18, each pitch-based region 1
8R, 18G, and 18B are formed within a plane of one dot, and the color filters 30R and 30 of each color are formed for each dot.
G and 30B are formed to form one pixel. In this case, in the semi-transmissive reflective layer 18, it is possible to reflect light close to white by the color mixture of the reflected light of each pitch region 18R, 18G, 18B within one dot, and for each pixel based on the reflected light. The color filter layer 30 enables color display. Further, the pitch-based regions 18R, 18
It is possible to transmit the complementary colored light in G and 18B,
Even with the color mixture, light close to white can be transmitted within one dot, and color display can be performed by the color filter layer 30 for each pixel based on the transmitted light.

Further, the pitch-specific regions 18R, 18G, 1
In 8B, while the light corresponding to the pitch is reflected while the complementary color is transmitted, the ratio of transmission to reflection is approximately 2: 1. Then, as shown in FIG. 3, in the present embodiment, each pitch region 18R,
Since 18G and 18B are formed so that their respective area areas are substantially equal to each other, the transmission / reflection ratio is approximately 2: 1 for each pixel.

Next, in the liquid crystal display device 10 of the present embodiment, the light incident from the external light passes through the upper polarizing plate 36 and the phase difference plate 35 to become clockwise circularly polarized light, and the clockwise circular The polarized light is incident on the liquid crystal layer 16. Here, when a voltage is applied between the scanning electrode 25 and the signal electrode 32 (when a selective electric field is applied), the liquid crystal layer 16 is turned on and the right-handed circularly polarized light is directly transmitted as the right-handed circularly polarized light. It is supposed to be. When no voltage is applied between the scanning electrode 25 and the signal electrode 32 (when no selective electric field is applied), the liquid crystal layer 16 is turned off to convert the clockwise circularly polarized light into the counterclockwise circularly polarized light. It is supposed to pass.

The right-handed circularly polarized light emitted from the liquid crystal layer 16 is absorbed by the color filter layer 30 at a predetermined wavelength. For example,
In the dye layer 30R corresponding to R (red), the wavelength of color light that is a complementary color of the wavelength corresponding to R (red) is absorbed, and G (green)
In the dye layer 30G corresponding to, the wavelength of the color light that is a complementary color of the wavelength corresponding to G (green) is absorbed, and in the dye layer 30B corresponding to B (blue), the complementary color of the wavelength corresponding to B (blue) The wavelength of the colored light is absorbed. Thus, for example, R
The wavelength of the clockwise circularly polarized light transmitted through the dye layer 30R corresponding to (red) is about 600 to 650 nm.

The right-handed circularly polarized light that has passed through the color filter layer 30 and becomes color light in a specific wavelength range is incident on the semi-transmissive reflective layer 18, and about 67 of the right-handed circularly polarized light that is incident on the semi-transmissive reflective layer 18. % Light is transmitted and about 33% is reflected. About 33% of the reflected right-handed circularly polarized light is again passed through the color filter layer 30, the liquid crystal layer 16, the upper substrate 14, the retardation plate 35, and the upper polarizing plate 36, and is used for display. When the liquid crystal layer 16 is not applied with a selective electric field, the left-handed circularly polarized light is incident on the semi-transmissive reflective layer 18, and the semi-transmissive reflective layer 18 does not reflect the left-handed circularly polarized light and is used for display. It is supposed not to be done.

On the other hand, the illumination light incident on the liquid crystal cell 11 from the illumination device 12 passes through the lower polarizing plate 28 and the phase difference plate 27 to become clockwise circularly polarized light, and is incident on the semi-transmissive reflective layer 18 from below. . Here, as in the case of outside light, about 33% of the incident right-handed circularly polarized light is reflected, and about 67% is reflected.
Of light is transmitted. In this case, about 67% of the right-handed circularly polarized light transmitted through the color filter layer 30, the liquid crystal layer 16,
The display is provided through the upper substrate 14, the retardation plate 35, and the upper polarizing plate 36.

As described above, in the liquid crystal display device 10 of the present embodiment, the semi-transmissive reflective layer 18 is arranged in the plane by pitch areas divided into cholesteric liquid crystal layers each having a spiral pitch corresponding to each of the three primary colors of light. 18R, 18G, 1
8B is included, it becomes possible to form the semi-transmissive reflective layer 18 thinly as compared with the case of obtaining a color mixture by stacking regions for each pitch, and thus the liquid crystal display device 10 is provided.
It is possible to reduce the size of the liquid crystal layer 16 and
It becomes possible to make the film thickness of the film relatively uniform. In addition,
In the present embodiment, the semi-transmissive reflective layer 18 has a thickness of about 1-2 μm.
The layer thickness is about m.

The semi-transmissive reflective layer 1 shown in this embodiment is used.
8 can be formed by the following method. For example, apply cholesteric liquid crystal evenly to a given substrate surface,
This is irradiated with ultraviolet rays. Here, it is assumed that the exposure is performed with an intensity distribution so that the ultraviolet intensities are different within the dots,
The helical pitch of the liquid crystal molecules can be different for each predetermined region depending on the strength, and the predetermined region is configured as the pitch-based region. It should be noted that instead of the intensity of ultraviolet rays, the wavelength of ultraviolet rays, heat, etc. are distributed in each dot,
It is also possible to change the helical pitch of liquid crystal molecules for each predetermined region. As shown in FIG. 3, since the pitch regions 18R, 18G, and 18B are each formed in a rectangular shape in plan view, the efficiency is improved during the exposure, and the area ratio of each region is designed. It will be easier.

Some examples of modifications of the semi-transmissive reflective layer 18 will be described below.

(First Modification) FIG. 4 is a plan view of the color filter layer 30 and the semi-transmissive reflective layer 18, similar to FIG. 3, in which the front side of the paper is the color filter layer 30 and the rear side of the paper is the semi-transparent. It is the reflective layer 18. In this modification, a region (selective color reflection region) 18R for each red reflection pitch capable of reflecting red color among the three primary colors of light within one dot
And a cyan reflection pitch area (complementary color reflection area) 18C capable of reflecting cyan, which is a complementary color of red, are formed. Also in this case, semi-transmissive reflection display close to white is possible by using red (selected color) and cyan (complementary color).

The ratio of reflection and transmission is approximately 1: 2 in the red reflection pitch-based region 18R, while the ratio of reflection and transmission is approximately in the cyan reflection pitch-based region 18C because it reflects color light other than red. It becomes 2: 1. As shown in the drawing, the red reflection pitch-based area 18R and the cyan reflection pitch-based area 18C are formed to have substantially the same area area, and the ratio of reflection to transmission is approximately 1: 1 for each pixel. Become. As shown in FIG. 5, the red reflection pitch-based regions 18R and the cyan reflection pitch-based regions 18C are each pitch-based regions 18R and 18C in the cholesteric liquid crystal layer having a pitch of a wavelength corresponding to each color.
It is possible to obtain C by forming it in a plane.

As shown in FIG. 6, it is also possible to obtain a cyan reflection pitch-specific region 18C by stacking a green reflection pitch-specific region 18G and a blue reflection pitch-specific region 18B corresponding to green and blue, respectively. In this case, the layer thickness of the semi-transmissive reflective layer 18 is larger than that of FIG. 5 due to the lamination of the green reflection pitch-based area 18G and the blue reflection pitch-based area 18B. In the case where white light is obtained by stacking layers, it is necessary to stack, for example, three layers, preferably six layers.
In this example, the semi-transmissive reflective layer 18 can be formed as a thin layer.

Further, in the example of FIG. 4, in one dot, the red reflection pitch-specific area 18R is set as the selection color reflection area.
And a cyan reflection pitch area 18C as a complementary color reflection area.
And are formed in a plane, a combination of a green reflection pitch area as a selection color reflection area and a magenta reflection pitch area as a complementary color reflection area, or a blue reflection pitch area as a selection color reflection area It is also possible to employ a combination of the above and the area for each yellow reflection pitch as the complementary color reflection area.

(Second Modification) Next, FIG. 7 is a plan view of the color filter layer 30 and the semi-transmissive reflective layer 18, as in FIG. 3, and the front side of the paper is the color filter layer 30,
The transflective layer 18 is on the rear side of the paper surface. In this modification,
Within one dot, each pitch area 18R, 18G,
Area 1 for each green reflection pitch corresponding to the green color of 18B
The maximum area is 8G. In this case, the reflectance of green becomes relatively large, and green has the highest visibility, so
The reflectance of the liquid crystal display device becomes relatively large. Therefore, it is possible to provide a display device that emphasizes reflective display. Specifically, within one dot, the pitch regions 18R, 18G, 18
The area ratio of B is approximately 1: 2: 1 in this order.

(Third Modification) Similar to FIG. 3, FIG. 8 is a plan view of the color filter layer 30 and the semi-transmissive reflective layer 18, in which the front side of the paper is the color filter layer 30 and the rear side of the paper is semi-transmissive. It is the reflective layer 18. In this case, of the pitch-specific regions 18R, 18G, and 18B, the area of the green reflection-pitch-specific region 18G corresponding to green is minimized. Therefore, it becomes possible to provide a display device with an emphasis on transmissive display, and in this modification, the area ratio of the pitch regions 18R, 18G, and 18B within one dot is approximately 2: 1: 2 in this order. Has been done.

[Electronic Equipment] Examples of electronic equipment equipped with the liquid crystal display device of the above embodiment will be described.

FIG. 9 is a perspective view showing an example of a mobile phone. In FIG. 9, reference numeral 1000 indicates a mobile phone main body, and reference numeral 1001 indicates a liquid crystal display unit using the above liquid crystal display device.

FIG. 10 is a perspective view showing an example of a wrist watch type electronic device. In FIG. 10, reference numeral 1100 indicates a watch body, and reference numeral 1101 indicates a liquid crystal display unit using the above liquid crystal display device.

FIG. 11 is a perspective view showing an example of a portable information processing device such as a word processor and a personal computer. In FIG. 11, reference numeral 1200 is an information processing apparatus, reference numeral 1202 is an input unit such as a keyboard, reference numeral 1204 is the information processing apparatus main body, and reference numeral 1206 is a liquid crystal display unit using the above liquid crystal display device.

Since the electronic equipment shown in FIGS. 9 to 11 uses the liquid crystal display device of the above embodiment, the display portion is formed thin. Further, since the liquid crystal layer has a relatively uniform film thickness, it is possible to realize an electronic device having high contrast and few display defects.

The technical scope of the present invention is not limited to the above-mentioned embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the above-described embodiments are not limited to the passive matrix type transflective color liquid crystal display device, but can be applied to an active matrix type liquid crystal display device of monochrome display. Further, in the above embodiment, the color filter layer is provided on the inner surface side of the lower substrate, but it may be provided on the inner surface of the upper substrate side.

[0048]

As described above in detail, according to the present invention, a semi-transmissive reflection of a liquid crystal display device is realized by a reflection plate including a pitch-based area in which a cholesteric liquid crystal layer is divided for each spiral pitch in a plane. The layer thickness is 1-2 μm because the layers are configured.
It is possible to form a cholesteric semi-transmissive reflective layer that is as thin as possible, and to realize a liquid crystal display device in which the liquid crystal layer has a uniform thickness. Further, in the liquid crystal display device of the present invention, it is possible to arbitrarily set the display ratio of transmission and reflection based on each area of the pitch-based regions in the semi-transmissive reflection layer.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a partial cross-sectional structure of a liquid crystal display device as an embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view showing an enlarged semi-transmissive reflective layer of the liquid crystal display device of FIG.

3 is a schematic plan view of a color filter layer and a semi-transmissive reflective layer of the liquid crystal display device of FIG.

FIG. 4 is a schematic plan view for explaining a modification of the semi-transmissive reflective layer.

5 is a partially enlarged cross-sectional view showing an enlarged view of the semi-transmissive reflective layer in FIG.

6 is a partially enlarged cross-sectional view showing a modified example of FIG.

FIG. 7 is a schematic plan view for explaining a modification of the semi-transmissive reflective layer.

FIG. 8 is a schematic plan view for explaining a modification of the semi-transmissive reflective layer.

FIG. 9 is a perspective view showing an example of an electronic device according to the invention.

FIG. 10 is a perspective view showing another example of an electronic device according to the present invention.

FIG. 11 is a perspective view showing still another example of an electronic device according to the present invention.

[Explanation of symbols]

10 Liquid crystal display device 11 Liquid crystal cell 12 Backlight (illuminator) 13 Lower substrate 14 Upper substrate 16 Liquid crystal layer 18 Semi-transmissive reflective layer 18R, 18G, 18B Pitch area 30 color filters

Claims (14)

[Claims] 1. A reflector comprising a cholesteric liquid crystal layer, capable of reflecting colored light having a wavelength according to a helical pitch of the cholesteric liquid crystal, wherein the cholesteric liquid crystal layer comprises:
A plurality of pitch-based regions each having a different helical pitch of the liquid crystal molecules are included in a plane, and in each of the plurality of pitch-based regions, colored light having a different wavelength corresponding to each helical pitch is reflected. Reflector. 2. The cholesteric liquid crystal layer is capable of reflecting a part of circularly polarized light having a predetermined rotation direction and transmitting a part thereof. Reflector. 3. The primary color reflection pitch-based region capable of reflecting any of the three primary colors of light for each color, wherein each of the plurality of pitch-based regions includes one of the three primary colors of light. a reflector. 4. The selected color reflection pitch-based area capable of reflecting any color selected from the three primary colors of light, and the plurality of pitch-based areas are complementary colors of the selected color. The reflection plate according to claim 1 or 2, further comprising a complementary color reflection pitch region capable of reflecting colors. 5. A liquid crystal display device having a liquid crystal cell in which a liquid crystal layer is sandwiched between an upper substrate and a lower substrate which are translucent substrates and are arranged to face each other, An upper substrate side circularly polarized light incident means for making circularly polarized light incident from the substrate side, and a lower substrate side circularly polarized light incident means for making circularly polarized light in the same rotation direction as the circularly polarized light from the upper substrate side incident from the lower substrate side; An illumination device that makes light enter the liquid crystal cell from the lower substrate side is provided, and the liquid crystal layer has a polarity of circularly polarized light that is incident in either one of a selective electric field applied state and a non-selective electric field applied state. Inverting and not reversing the polarity in the other state, a semi-transmissive reflective layer is provided on the inner surface side of the lower substrate, and the semi-transmissive reflective layer includes a cholesteric liquid crystal layer, and the spiral pin of the cholesteric liquid crystal is included. The cholesteric liquid crystal layer includes a plurality of pitch-based regions in which the helical pitches of the liquid crystal molecules are different from each other in a plane, and each of the plurality of pitch-based regions has a different pitch. A liquid crystal display device, characterized in that color lights of different wavelengths are reflected according to the respective spiral pitches. 6. The semi-transmissive reflective layer includes, in a plane, a plurality of pitch-based regions partitioned within a dot for each helical pitch of liquid crystal molecules, and the plurality of pitch-based regions are provided for each region. 6. The liquid crystal display device according to claim 5, wherein color lights having different wavelengths depending on the spiral pitch can be reflected. 7. The liquid crystal display device according to claim 6, wherein each color includes a region for each primary color reflection pitch capable of reflecting any one of the three primary colors of light in the one dot. 8. The liquid crystal display device according to claim 7, wherein the areas of the respective primary color reflection pitches corresponding to the respective three primary colors of light are formed to have substantially the same area. 9. The area of each of the primary color reflection pitch regions corresponding to each of the three primary colors of light is maximized in the area of each green reflection pitch region corresponding to green. Liquid crystal display device. 10. The area of each of the primary color reflection pitch regions corresponding to each of the three primary colors of light is minimized in the area of each green reflection pitch region corresponding to green. Liquid crystal display device. 11. A selected color reflection area capable of reflecting any color selected from the three primary colors of light within one dot, and a color complementary to the selected color. 7. The liquid crystal display device according to claim 6, wherein a complementary color reflective region capable of performing the above is formed. 12. The liquid crystal display device according to claim 11, wherein the selective reflection area and the complementary color reflection area are formed to have substantially the same area. 13. The liquid crystal display device according to claim 6, wherein each of the plurality of pitch-based regions is formed in a rectangular shape. 14. An electronic apparatus comprising the liquid crystal display device according to claim 5. Description: