JPH10142593A - Reflection type liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an element which has high reflectivity by including two liquid crystal layers which consist of materials having the same twist direction and selectively reflecting the circularly polarized light in the same direction and a sepn. layer which has optical rotating power, thereby enhancing the utilization efficiency of light. SOLUTION: This liquid crystal display element consists of a first cell 1 and a second cell 2 and a separating member 3 interposed between the first cell 1 and the second cell 2. The first cell 1 is manufactured by injecting a liquid crystal material 18 having a clockwise twisting structure between transparent substrates 11 and 12 formed with electrode layers 13, 14 consisting of conductive materials, such as ITO and Al, and semiconductor materials. Similarly, the second cell 2 is manufactured by injecting a liquid crystal material 28 having a counterclockwise twisting structure between the transparent substrates 21 and 22. A layer formed by holding a glass layer having no optical rotating power or refractive index matching oil (matching oil) with the transparent substrates, etc., are usable for the separating member 3. More particularly the layer consisting of the refractive index matching oil is more preferable as this layer prevents the reflection, etc., between the transparent substrates 12 and 21 holding this layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a reflection type liquid crystal display device.

[0002]

2. Description of the Related Art In general, a liquid crystal display element is enclosed by a pair of substrates arranged opposite to each other at a fixed distance, electrodes provided on mutually opposing surfaces of the substrates, and an alignment film interposed between the substrates. Liquid crystal material. In this liquid crystal display element, the optical characteristics of the liquid crystal are controlled by applying a voltage between opposing electrodes.

In recent years, in particular, an electrode on a substrate is divided into pixels, and a thin film transistor (TFT, Thin Film
An active matrix type liquid crystal display element which applies a voltage to a pixel electrode by providing a switching element such as an nsistor) has been developed and put into practical use.

Among such liquid crystal display elements, a twisted nematic element for switching between a bright state and a dark state using a polarizing plate by utilizing a change in optical properties of a liquid crystal material, SSFL
C and AFLC. However, since the liquid crystal display element having such a display mode uses a polarizing plate as an essential component, its light use efficiency is only about 50% at the maximum.

A display mode called a selective reflection mode of a cholesteric liquid crystal material that selectively reflects light having a specific wavelength due to a complicated twisted structure of the liquid crystal material is described in George H.
Heilmeier, Joel E. Goldmacher, (Appl.phys.Lett., 1
3 (1968)). This mode includes a transparent state involving reflection of light wavelengths outside the visible light region in a planar (Planar) structure state in which the spiral axis is oriented substantially perpendicular to the element substrate surface, and a spiral axis substantially parallel to the substrate surface. Light switching is performed using a scattering (or weak scattering) state in a proper focal conic structure state.

In this mode, since a display is performed in a transparent state in a visible light region in a planar state and a weakly scattered transmission state in a focal conic state, a display with a relatively high contrast is possible, but the reflection efficiency in the planar structure is right. Alternatively, since only a specific wavelength region of left-handed circularly polarized light is reflected, the reflectance is 50% as a limit value. In this mode, a right-handed polymer dispersed cholesteric liquid crystal (PDCLC) layer that selectively reflects only right-handed circularly polarized light and a left-handed light-rotating PDCLC that selectively reflects only left-handed circularly polarized light in order to increase the reflectance to 50% or more. (See Japanese Patent Application Laid-Open No. 7-287).
214). In this method, since the left and right circularly polarized light can be reflected, a reflectance of practically 50% or more can be expected. However, since the polymer dispersion type structure is used, the control of the matrix state for forming the twisted structure is delicate. Further, by forming a mixed state with the polymer, the driving voltage is increased. In particular, there is a problem in that a material having a high threshold value requires a very large voltage for driving due to the twisted structure of the liquid crystal material. Furthermore, in this method, slight scattering occurs at the time of transmission, so there is a limit to the improvement of contrast.
In addition, the problem that the driving voltage is relatively high remains.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a reflective liquid crystal display device having high light utilization efficiency and high reflectance. With the goal. Another object of the present invention is to provide a reflective liquid crystal display device having a low driving voltage.

[0008]

To achieve the above object, the present invention (claim 1) provides a substrate having a pixel electrode formed on a surface thereof and a first liquid crystal layer provided on the substrate. A second liquid crystal layer provided on the first liquid crystal layer, a counter electrode formed on the second liquid crystal layer, and a second liquid crystal layer provided between the first liquid crystal layer and the second liquid crystal layer. A separating member for separating the first liquid crystal layer and the second liquid crystal layer, wherein the first and second liquid crystal layers each have the same twist direction and selectively reflect circularly polarized light in the same direction. The reflective layer is made of a material, and the separation layer has optical rotation.

According to the present invention (claim 2), the first liquid crystal layer has a twist pitch p1 and the second liquid crystal has a twist pitch p2, and the twist directions are the same. The first liquid crystal layer has a mean refractive index n1 and a twist pitch p1.
Λ1 = n1 · p
Wavelength width Δn · p1 (Δn = ne1-no1:
ne1 is a refractive index of the extraordinary light component of the first liquid crystal layer, and no1 is a function that shifts the phases of the ordinary light component of the light of the first liquid crystal layer and the extraordinary light component by approximately a half wavelength. A reflective liquid crystal display device is provided. The present invention (claim 3) provides a substrate having a pixel electrode formed on a surface thereof, a first liquid crystal layer provided on the substrate,
A second liquid crystal layer provided on the second liquid crystal layer, a counter electrode formed on the second liquid crystal layer, and a first liquid crystal layer provided between the first liquid crystal layer and the second liquid crystal layer. And a separating member for separating a second liquid crystal layer, wherein the first and second liquid crystal layers have the same twist direction and are made of a liquid crystal material that selectively reflects circularly polarized light in the same direction. The difference Δλ between the selective reflection center wavelength λ1 of the liquid crystal material of the first liquid crystal layer and the selective reflection wavelength λ2 of the liquid crystal material of the second liquid crystal layer is 30 nm <Δλ <100 nm. Provided is a liquid crystal display device.

The present invention (claim 4) provides a substrate having a pixel electrode formed on a surface thereof, a first liquid crystal layer provided on the substrate, and a first liquid crystal layer provided on the first liquid crystal layer. 2 liquid crystal layer, a counter electrode formed on the second liquid crystal layer, and a first liquid crystal layer and a second liquid crystal layer provided between the first liquid crystal layer and the second liquid crystal layer. A separating member, wherein the first and second liquid crystal layers have different twist directions,
Made of liquid crystal material that selectively reflects circularly polarized light in different directions,
The difference Δλ between the selective reflection center wavelength λ1 of the liquid crystal material of the first liquid crystal layer and the selective reflection wavelength λ2 of the liquid crystal material of the second liquid crystal layer is 30 nm <Δλ <100 nm. A liquid crystal display device is provided. The present invention (claim 5) provides a substrate having a pixel electrode formed on a surface thereof, a first liquid crystal layer provided on the substrate, and a second liquid crystal provided on the first liquid crystal layer. Layers and
A counter electrode formed on the second liquid crystal layer;
A separating member provided between the liquid crystal layer and the second liquid crystal layer for separating the first liquid crystal layer and the second liquid crystal layer, the separating member having a thickness of 1 μm or less, and having a thickness of 400 nm to 650 μm.
Provided is a reflective liquid crystal display device, which is made of a material capable of transmitting light having a wavelength of nm.

The present invention (claim 6) provides a substrate having a pixel electrode formed on a surface thereof, a first liquid crystal layer formed of a chiral nematic liquid crystal material provided on the substrate, and a first liquid crystal layer formed of a chiral nematic liquid crystal material. A second liquid crystal layer made of a chiral nematic liquid crystal provided thereon, a counter electrode formed on the second liquid crystal layer, and a first liquid crystal layer provided between the first liquid crystal layer and the second liquid crystal layer. A separating member for separating the liquid crystal layer and the second liquid crystal layer, a first electrode formed on a surface of the separating member facing the first liquid crystal layer, and a second liquid crystal layer of the separating member. A second electrode formed on an opposing surface, wherein the first electrode and the second electrode are electrically connected via a through hole provided in the separation member, and the pixel electrode and the counter electrode are provided. By applying a voltage in between, the first
A reflective liquid crystal display device characterized by simultaneously driving the liquid crystal layer and the second liquid crystal layer.

The present invention (claim 7) provides a substrate having a pixel electrode formed on a surface thereof, a first liquid crystal layer provided on the substrate, and a first liquid crystal layer provided on the first liquid crystal layer. 2 liquid crystal layer, a counter electrode formed on the second liquid crystal layer, and a first liquid crystal layer and a second liquid crystal layer provided between the first liquid crystal layer and the second liquid crystal layer. A separation member, the separation member having anisotropic conductive properties, and applying a voltage between the pixel electrode and the counter electrode to form the first liquid crystal layer and the second liquid crystal layer. A reflective liquid crystal display element driven simultaneously is provided.

The present invention (claim 8) provides the reflective liquid crystal display device according to claim 7, wherein the first and second liquid crystal layers are made of a chiral nematic liquid crystal material.

Further, according to the present invention (claim 9), the chiral nematic liquid crystal material is a mixed liquid crystal of a nematic liquid crystal and a chiral substance including a cholesteric liquid crystal, and the light having a wavelength of 350 nm to 650 nm is generated by the twisted structure of the liquid crystal. 9. A reflective liquid crystal display device according to claim 6, wherein the reflective liquid crystal display device reflects light.

Further, according to the present invention (claim 10), the twisting direction of the chiral nematic liquid crystal material forming the first liquid crystal layer is the same as the twisting direction of the chiral nematic liquid crystal material forming the second liquid crystal layer. 8. A phase compensating layer for changing the direction of circularly polarized light of light transmitted through the second liquid crystal layer between the first liquid crystal layer and the second liquid crystal layer. 8. A reflective liquid crystal display device according to item 8.

Further, according to the present invention (claim 11), the chiral nematic liquid crystal material constituting the first liquid crystal layer as the phase compensation layer has an average refractive index n1 and a pitch p1 of a twisted structure.
The wavelength width Δn1 · p1 (Δn = ne1-no1: ne1 where n1 is the refractive index of the extraordinary light component of the first liquid crystal layer and no1 is the ordinary light of the first liquid crystal layer) 11. A reflective liquid crystal display device according to claim 10, wherein an optical film capable of shifting the phases of the ordinary light component and the extraordinary light component of the component (refractive index of the component) by approximately half a wavelength is used.

Further, according to the present invention (claim 12), the separating member is formed by bonding a glass substrate, and the optical film is configured to be sandwiched between the glass substrates. Provided is a reflective liquid crystal display device.

Further, according to the present invention (claim 13), the twisting direction of the chiral nematic liquid crystal material forming the first liquid crystal layer is opposite to the twisting direction of the chiral nematic liquid crystal material forming the second liquid crystal layer. 10. The reflective liquid crystal display device according to claim 6, wherein the separation member is made of a film or glass that does not exhibit optical rotation.

Further, according to the present invention (claim 14), the first and second electrodes formed on the separating member are formed for each pixel, and are electrically independent of other pixels to allow charge to enter and exit. 6. A non-floating state.
A reflective liquid crystal display device according to 8, 9, 10, 11, 12, or 13 is provided.

The present invention (claim 15) is characterized in that the first and second electrodes have the same or different surface areas, respectively.
2. A reflective liquid crystal display device according to 2, 13, or 14.

The present invention (claim 16) provides a reflective liquid crystal display device according to claim 15, wherein the surface area of the second electrode is larger than the surface area of the first electrode. I do.

Further, the present invention (claim 17) is characterized in that the first
The difference Δλ between the selective reflection center wavelength λ1 of the chiral nematic liquid crystal material of the liquid crystal layer and the selective reflection center wavelength λ2 of the chiral nematic liquid crystal material of the second liquid crystal layer is 30 nm <Δ.
7. A lens according to claim 6, wherein λ <100 nm is satisfied.
8, 9, 10, 11, 12, 13, 14, 15, or 1
6. A reflective liquid crystal display device according to item 6.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below. However, what is listed here is only an example for explaining the present invention, and the present invention can be variously modified and used. As a liquid crystal material used in the liquid crystal display device of the present invention, chiral nematic liquid crystal which is a mixture of cholesteric liquid crystal and nematic liquid crystal can be mainly used. Further, the chiral nematic liquid crystal used in the present invention is preferably prepared by adding a chiral agent to the nematic liquid crystal preferably in an amount of 30% to
Obtained by adding 50%. At this time, depending on the spontaneous pitch of the chiral agent, a chiral agent of 30% or less can be used. By using these chiral nematic liquid crystals, light having a wavelength of 350 nm to 650 nm can be reflected. Further, when a perfluoroalkyl compound or the like is added to these chiral nematic liquid crystals at a ratio of 1 to 3% by weight, it is effective in widening the selective reflection wavelength range.

As a substrate material used for the liquid crystal display element of the present invention, a glass substrate, a transparent resin substrate, a heat-resistant resin substrate and the like can be mentioned. In the liquid crystal display element of the present invention, as the spacer, a resin ball sprayed on the substrate surface can be used. In addition, when the substrates are combined, there is no possibility that the spacers come close to each other, and the spacers can be uniformly dispersed in the plane. Therefore, it is preferable to use insulating columns formed at predetermined intervals on the substrate surface.

In the present invention, the selective reflection of the circularly polarized light is, specifically, that the light incident parallel to the torsion (helical) axis of the liquid crystal material in the planar structure is split into two circularly polarized lights, right-handed and left-handed. , One transmits light and the other reflects all.

Here, when the polarization direction of the circularly polarized light is defined toward the incident light, the circularly polarized light having the same direction as the twisted direction is selectively scattered and reflected. In the present invention, when the twist directions of the first liquid crystal layer in the first cell and the second liquid crystal layer in the second cell are different from each other, for example, the first liquid crystal layer in the first cell has a right circular shape. When the polarized light is reflected and the second liquid crystal layer in the second cell reflects left-handed circularly polarized light, the separating member disposed between the first cell and the second cell effectively reflects light. In order to preserve circularly polarized light so that it can be performed, it is preferable that it has no optical rotation.

In the present invention, when the twist directions of the first liquid crystal layer in the first cell and the second liquid crystal layer in the second cell are equal, for example, the first and second liquid crystal layers in the first cell When any of the liquid crystal layers selectively reflects right circularly polarized light or selectively reflects left circularly polarized light, the separating member disposed between the first cell and the second cell is used after the first cell has passed through the first cell. In order to convert the circular polarization of light from right to left or from left to right, it is preferable to have optical rotation.

In this case, as the separating member, a wavelength width ・ n · p1 (△ 1) having a selective reflection wavelength center value λ1 = n1 · p1 determined by the average refractive index n1 of the first liquid crystal layer and the twist pitch p1. n = ne1-no1: ne1 is the first
(No1 is the refractive index of the ordinary light component of the first liquid crystal layer), and the optical compensating element has a function of shifting the phases of the ordinary light component and the extraordinary light component of light by approximately half a wavelength. Is preferred.

Further, in any of the above-mentioned cases, the profile of the selectively reflected light of the first liquid crystal layer and the profile of the selectively reflected light of the second liquid crystal layer are different from each other in a certain range, but are whitish as a whole. Color reflection can be expected, and the reflectance is also improved.

FIG. 19 shows a diagram of the overall reflection characteristic obtained by superimposing the selective reflection profile A of the first liquid crystal and the selective reflection profile B of the second liquid crystal. As shown in the figure, when reflection is expected over a wide wavelength range, it is preferable to make the central wavelengths of selective reflection of the respective liquid crystal layers differ by about 30 nm to 100 nm. That is, it is preferable that the difference Δλ between the central selective reflection wavelength λ1 of the first liquid crystal layer and the central selective reflection wavelength λ2 of the second liquid crystal layer is set to 30 nm <Δλ <100 nm.

This is because if the selection Δλ is 30 nm or less, the peak is concentrated at a certain wavelength, and the reflected light becomes, for example, greenish. On the other hand, if △ λ exceeds 100 nm, the peaks are separated as shown in the figure, resulting in a color in which the two colors are mixed. Therefore, by setting the value of △ λ in the above range, it is possible to obtain a whitish and high reflectance as a whole. In the present invention, the material of the thin film used for the separation member is preferably an electrically insulating material that does not allow liquid crystal molecules to permeate or permeate and has no solubility in the liquid crystal material, such as polyimide, polyamide, or polyamic acid. Used. As the material of the film having optical rotation, a high refractive index material such as a polymer liquid crystal material or an inorganic material having a refractive index equivalent thereto can be used. The thin film preferably has flexibility, and is preferably an organic thin film. Further, a material having high gas insulating properties is preferable, and it is preferable to coat an ultrathin film of an inorganic insulating material on an organic thin film. In particular, an inorganic thin film showing flexibility is ideal.

The thickness of the thin film is preferably 1 μm or less in order to eliminate parallax between the two (upper and lower) liquid crystal layers. Further, the thin film having the above thickness, which is made of the above material, can transmit light having a wavelength of 400 nm to 650 nm satisfactorily.

As a method of forming a thin film, a method of forming a water surface spread film (a laminated film of a film having a thickness of about 100 angstroms) or the like can be used. The thin film is
When a cell is assembled with a pair of substrates, two or more regions are formed by being pressed against the substrates by the spacers. That is, a spacer is provided on each of the opposing surfaces of the pair of substrates, and the thin films are inserted so that the respective substrates are arranged to face each other. In this way, the thin film is pressed by the spacer formed on each substrate,
The regions are separated in the cell thickness direction. In this case, the sum of the intervals between the regions (the thickness of the liquid crystal layer) is the substrate interval D. For example, when divided into two regions by a thin film,
Assuming that the distance between the respective regions (the thickness of the liquid crystal layer) is D1 and D2, the thickness of the thin film is small, so that D1 + D2 = D (constant value). For this reason, it is possible to keep the image quality uniform without showing a clear section for each area. Note that these 2
The one or more regions include a region including a liquid crystal material that selectively reflects right circularly polarized light and a region including a liquid crystal material that selectively reflects left circularly polarized light.

In the present invention, unlike the conventional method of manufacturing a liquid crystal display element, cells are assembled by dispersing spacers on both substrates of a pair of substrates. This is intended not only for the purpose of keeping the distance between the substrates constant by the spacers, but also for supporting a thin film partitioned into two or more regions, and for spontaneously forming a space for holding an independent liquid crystal material. Because it is the purpose.

Next, the structure of the liquid crystal display device of the present invention will be specifically described. First, FIG. 1 shows a first embodiment of the present invention. This liquid crystal display element is mainly composed of a first cell 1, a second cell 2, and a separating member 3 interposed between the first cell 1 and the second cell 2.

The first cell 1 includes a pair of transparent substrates 11, 1
2, electrode layers 13 and 14 made of a conductive material such as ITO and Al, a semiconductor material, and the like are formed, respectively.
After the alignment films 15 and 16 are formed on the alignment film 14 and a predetermined alignment process is performed on each of the alignment films 15 and 16 as necessary, spacer balls 17 are sprayed on at least one of the alignment films to form an alignment film 15. , 16 are opposed to each other so that the transparent substrates 11 and 12 are opposed to each other, and a liquid crystal material 18 having a twisted right-handed structure (selective reflection of right circularly polarized light) is injected between the transparent substrates 11 and 12. It is produced by this.

The second cell 2 includes a pair of transparent substrates 2.
Electrode layers 23 and 24 made of a conductive material such as ITO and Al, a semiconductor material and the like are formed on the electrode layers 1 and 22 respectively, and alignment films 25 and 26 are formed on the electrode layers 23 and 24, respectively. , 26 are subjected to a predetermined alignment treatment, and a spacer ball 27 having a density of about 1 is formed on at least one of the alignment films.
00 pieces / mm ² was sparged below, as the alignment films 25 and 26 face each other, the transparent substrates 21, 22 are opposed disposed, structural twisting between the transparent substrates 21, 22 is wound counterclockwise (left-handed circularly polarized light Is produced by injecting a liquid crystal material 28 (selective reflection).

In the first and second cells 1 and 2, when forming the alignment films 15, 16, 25 and 26, columnar spacers may be formed using an alignment film material. As the material of the alignment film, polyimide, polyamic acid, a surfactant and the like which are usually used can be used. Further, it is preferable that the formation density of the spacer balls and the columnar spacers is about 100 pieces / mm ² or less.

As the separating member 3, a glass layer having no optical rotation, a layer in which a refractive index matching oil (matching oil) is sandwiched between transparent substrates, or the like can be used. In particular, the layer made of the refractive index matching oil is formed on the transparent substrates 12 and 21 sandwiching this layer.
This is preferable because reflection between them is prevented. In the liquid crystal display device having the above configuration, the electrode layer 13 of the first cell 1
A voltage is applied to each of the electrode layers 23 and 24 of the second cell 14 and the second cell 2. Further, in this liquid crystal display element, since the right-handed liquid crystal material is injected into the first cell 1, the left circularly polarized component of the incident light is passed and the right circularly polarized component is reflected. Since the left-handed liquid crystal material is injected into the second cell 2, the right circularly polarized component of the incident light passes through and the left circularly polarized component is reflected. Therefore, the left-circularly polarized light component transmitted through the first cell 1 is reflected by the second cell 2. This allows the reflectance,
Reflection luminance and contrast can be improved. Also, the center wavelength of the wavelength of the light selectively reflected from each layer △ λ
Is controlled to be longer than 30 nm and shorter by 100 nm, so that the reflection wavelength width can be widened and whitish.

Next, FIG. 2 shows a second embodiment of the present invention. This liquid crystal display element mainly includes a first cell 1, a second cell 2, and a separating member 4 interposed between the first cell 1 and the second cell 2.

The configuration of the first and second cells 1 and 2 is the same as that shown in FIG. However, the liquid crystal material is the first
In each of the second and first cells 1 and 2, a liquid crystal material 18 whose twisted structure is right-handed (selective reflection of right-handed circularly polarized light) is injected.
As the liquid crystal material, a liquid crystal material 28 having a twisted structure with a left-handed twist (selective reflection of left-handed circularly polarized light) may be injected into both the first and second cells 1 and 2.

As the separating member 4, an optical compensatory element having optical rotation can be used. This optical compensating element
The circular polarization state of the component transmitted through the first cell 1 is changed to a circular polarization state that can be reflected by the second cell 2.
Also in the liquid crystal display device having the above configuration, the electrode layers 13 and 14 of the first cell 1 and the electrode layers 2 and
A voltage is applied to each of the reference numerals 3 and 24.
Further, in this liquid crystal display device, since the right-handed liquid crystal material is injected into the first and second cells 1, the left circularly polarized component of the incident light is passed and the right circularly polarized component is reflected. . The component of the left circularly polarized light transmitted through the first cell 1 is converted into right circularly polarized light by the separation member 4. The component of the right circularly polarized light is reflected by the second cell 2. Thereby, the reflectance, the reflection luminance, and the contrast can be improved. By controlling the wavelength of the reflected light to 30 nm <△ λ <100 nm, as in the first embodiment, the reflection wavelength width can be widened and set to whitish.

In this case, as compared with the case where chiral nematic liquid crystals having different twist directions are stacked and used, the liquid crystal materials having the same twist direction are used, so that the liquid crystal materials can be simultaneously injected and the process can be simplified. Also, cell pitch adjustment and the like can be easily performed. Next, the structure of another liquid crystal display element of the present invention will be specifically described. First, an embodiment of the present invention is shown in FIG. This liquid crystal display device has an IT on a pair of transparent substrates 11 and 12, respectively.
Electrode layers 13 and 14 made of a conductive material such as O and Al, a semiconductor material, and the like are formed, and an alignment film 1 is formed on the electrode layers 13 and 14.
5 and 16 are formed. Next, the respective alignment films 15 and 16
After performing a predetermined alignment treatment as necessary, spacer balls 17 are sprayed on the alignment films of both transparent substrates 11 and 12. Next, the thin film 31 is sandwiched between the transparent substrates 11 and 12 so that the alignment films 15 and 16 face each other.
The first and second regions 32 and 33 are formed by disposing the transparent substrates 11 and 12 so as to face each other. A liquid crystal material 18 having a twisted structure with a right-handed twist (selective reflection of right circularly polarized light) is injected into the first region 32, and a liquid crystal material with a left-handed twisted structure (selective reflection of left circularly polarized light) is injected into the second region 33. 28. When forming the alignment films 15 and 16, a columnar spacer may be formed using an alignment film material. As the material of the alignment film, polyimide, polyamic acid, a surfactant and the like which are usually used can be used. Further, the formation density of the spacer balls or columnar spacers is preferably about 50 / mm ² or less.

In the liquid crystal display device having the above configuration, a voltage is applied to the electrode layers 13 and 14. In this liquid crystal display device, the first region 3
2, a right-handed liquid crystal material 18 is injected.
The left-handed liquid crystal material 28 is injected into the region 33. Therefore, in the first region 32, the left circularly polarized component of the incident light passes through and the right circularly polarized component is reflected. In the second region, the right circularly polarized light component of the incident light passes, and the left circularly polarized light component is reflected. For this reason, the component of the left circularly polarized light transmitted through the first region 32 is
Are reflected in the region 33. This allows the reflectance,
Reflection luminance and contrast can be improved. Since the first region 32 and the second region 33 are defined by the thin film 31 made of a material that does not allow liquid crystal molecules to permeate or permeate, the right-handed liquid crystal material 18 and the left-handed liquid crystal material 28 are mixed. Not done. Further, by adjusting the magnitude of the voltage, the twist pitch changes, the wavelength of the light to be selectively reflected can be controlled, and the reflection wavelength width can be set wide. Next, another embodiment of the present invention is shown in FIG. This liquid crystal display element includes a pair of transparent substrates 1
Electrode layers 13 and 14 made of a conductive material such as ITO and Al, a semiconductor material, and the like are formed on the first and second electrodes 12, 12, respectively. Next, alignment films 15 and 16 are formed on the electrode layers 13 and 14, and the respective alignment films 15 and 16 are subjected to a predetermined alignment treatment as necessary. Pinch it. Next, the transparent substrates 11 and 12 are arranged so as to face each other so that the alignment films 15 and 16 face each other.
And the second regions 32 and 33 are formed. Next, a liquid crystal material 18 having a right-handed twisted structure (reflecting right circularly polarized light) is injected into the first region 32, and a liquid crystal material having a left-handed twisted structure (reflecting left circularly polarized light) is injected into the second region 33. 28. In this case, the spacer pillars 34 are formed when forming the alignment films 15 and 16. As the material of the alignment film, polyimide, polyamic acid, a surfactant and the like which are usually used can be used. Further, it is preferable that the formation density of the spacer columns is about 100 / mm ² or less.

In the liquid crystal display device having the above-described structure, a voltage is applied to the electrode layers 13 and 14. In this liquid crystal display element, the right-handed liquid crystal material 18 is injected into the first region 32, and the left-handed liquid crystal material 2 is injected into the second region 33.
8 have been injected. However, since the first region 32 and the second region 33 are defined by the thin film 31 made of a material that does not allow or allow liquid crystal molecules to permeate, the right-handed liquid crystal material 18 and the left-handed liquid crystal material 28 are not mixed. .

This liquid crystal display element has a first region 32
Through the incident light, the component of the left circularly polarized light passes, and the component of the right circularly polarized light is reflected. In the second region, the right circularly polarized light component of the incident light passes and the left circularly polarized light component is reflected. The left-circularly polarized light component transmitted through the first region 32 is reflected by the second region 33. Thereby, the reflectance, the reflection luminance, and the contrast can be improved. In addition, the wavelength of the reflected light can be controlled, and the reflection wavelength width can be set wide.

FIG. 5 is a sectional view of a reflection type liquid crystal display device according to another embodiment of the present invention. A pixel electrode 106 is formed on the lower substrate 102, and the pixel electrode 106 is connected to a TFT 105 as a switching element. The pixel electrode 106 and the TFT 105 are connected to the black light absorber 11.
0 covers the entire surface, and light incident from the upper surface is completely absorbed in this portion.

The first liquid crystal layer 1 is provided on the lower substrate 106.
17 and a second liquid crystal layer 118 are formed in this order.
An upper substrate 101 on which a common electrode (counter electrode) 104 is formed is provided thereon.

First liquid crystal layer 117 and second liquid crystal layer 118
A separation member 103 for separating the first liquid crystal layer 117 and the second liquid crystal layer 118 is provided between the first liquid crystal layer 117 and the second liquid crystal layer 118.
The separation member 103 has a first electrode 109 and a second electrode 109 on surfaces facing the first liquid crystal layer 117 and the second liquid crystal layer, respectively.
Electrodes 108 are formed. This first electrode 109
The second electrode 108 is electrically connected to the second electrode 108 through a through hole 107 provided in the separation member 103.

The first and second liquid crystal layers 117 and 118 of the lower substrate 102, the upper substrate 101, and the separating member 103, respectively.
In order to stabilize the adsorption of liquid crystal molecules,
The polyimide films 114, 111, 112, and 113 may be uniformly covered, or may be subjected to an alignment treatment depending on the purpose of use.

In the case of forming an alignment film, it is more preferable to form a columnar spacer using the same material as that of the alignment film in order to keep the cell interval constant. Further, resin spacer balls may be dispersed on the substrate surface by spraying.
However, the spacer ball density is preferably 100 balls / mm 2 or less.

The first and second liquid crystal layers 117, 11
In FIG. 8, a left-handed material 116 and a right-handed material 117 having a twisted structure between liquid crystal molecules are sandwiched, and the central wavelength of each reflected light is shifted to reflect and scatter the light.

In this case, the separation layer 103 between the first liquid crystal layer and the second liquid crystal layers 117 and 118 is preferably made of a material such as glass having no optical rotation, but may be a polymer film. .

The first and second liquid crystal layers 117, 118
When liquid crystal materials that reflect circularly polarized light in the same direction are used, at least the first liquid crystal layer 117 and the second liquid crystal layer 1
An optical filter for converting the optical rotation direction of light to the opposite direction is provided as a separating member between the optical filter and the optical filter.

In this manner, light having circularly polarized light in both the left and right directions can be selectively reflected, and the light use efficiency can be improved. In the present invention, the first liquid crystal layer 117 and the second liquid crystal layer 118 are used.
, A separating member 103 is provided, and further, electrodes 109 and 110 are provided on a surface facing the first and second liquid crystal layers, and each is connected by a through hole 107. In this manner, when a voltage is applied between the pixel electrode 106 and the counter electrode 104, a voltage drop at the separation member 103 can be ignored, so that power consumption can be reduced. In the present invention, the separation member 103 can be formed of an anisotropic conductive film as shown in FIG. Here, the same portions as those in FIG. 5 are denoted by the same reference numerals, and detailed description thereof will be omitted. When an anisotropic conductive film is used as the separation member 103 as described above, the electrodes 109 and 108 as shown in FIG. 5 need not be particularly provided. It is preferable to use it because the voltage is uniformly applied.

Further, in FIG. 6, the pixel electrode 106 is also formed on the alignment film 114 via a contact hole. In this way, the pixel electrode can be formed on the TFT 105, so that the driving region of the liquid crystal can be widened.

It is effective to use a conductive polymer or the like as the anisotropic conductive film used for the separation member 103. For example, polysilane, polycopper phthalocyanine, polyvinyl carbazole / trinitrofluorenone, polyacetylene, polythiophene, polypyrrole, polyaniline, polyarylene vinylene, and the like are used. In particular, polysilane and polyarylene vinylene, etc. can have two states of conductivity and insulation due to local exposure to ultraviolet light or local heating with a YAG laser or the like. It is suitable to be applied in a state.

In order to improve the conductive properties, a technique of locally exposing an organic thin film such as a polysilane film to ultraviolet light to form a polysiloxane and then doping a conductive semiconductor such as ITO with the use of a technique is used. It is also possible to actively try to improve the characteristics.

Due to the presence of these anisotropic conductive films, the capacitance component composed of the first liquid crystal layer and the second liquid crystal layer can be considered as a capacitor that is electrically connected almost in series. It is possible to avoid descent.

According to the present invention, the liquid crystal material used for the first liquid crystal layer 117 and the second liquid crystal layer 118 is a mixed liquid crystal material of a nematic liquid crystal and a chiral substance containing a cholesteric liquid crystal. 350 nm to 6
It reflects light having a wavelength of 50 nm. By doing so, the visible light region is selectively reflected.

As the liquid crystal material, chiral nematic liquid crystal which is a mixture of cholesteric liquid crystal and nematic liquid crystal can be mainly used. In order to stabilize the liquid crystal molecular arrangement, it is also effective to use a composite liquid crystal material (Japanese Patent Application No. Hei 7-341185) in which a perfluoroalkyl compound-based material is mixed with 1% to 3% of these chiral nematic liquid crystals. .

The first liquid crystal layer 117 and the second liquid crystal layer 118
When a liquid crystal material that reflects circularly polarized light in different directions is used, the separating member 103 preferably does not exhibit optical rotation. Further, the wavelength profile of light selectively reflected by the first liquid crystal layer 117 and the second liquid crystal layer 118 can be reflected in a wide range by making the central wavelength of selective reflection different between these regions by about 30 nm to 100 nm. A whitish display becomes possible.

On the other hand, when the first liquid crystal layer 117 and the second liquid crystal layer 118 are provided with a liquid crystal material that selectively reflects circularly polarized light in the same direction, it is preferable that the separating member 103 be formed of a material having optical rotation. . In particular, in this case, the center wavelength λ1 of the light selectively reflected by the first liquid crystal layer 117 = n1 · p1 (
n1 is the average refractive index of the first liquid crystal layer 117, p1 is the twist pitch of the liquid crystal material of the first liquid crystal layer 117, and the reflection wavelength width λ1 = Δn1 · p1 (Δn1 is the first liquid crystal layer 117). It is preferable that the optical element is capable of shifting the phase difference between the ordinary light component and the extraordinary light component of the liquid crystal material in the liquid crystal material) by a half wavelength.

As the spacer material for keeping the space (cell gap) constituting the liquid crystal layer at a constant interval, a conventionally used material obtained by scattering resin balls on the substrate surface can be used. A columnar insulator formed at a specific interval is preferable.

(Examples) Embodiments of the present invention will be specifically described below with reference to the drawings. (Example 1) I was placed on two glass substrates having a thickness of 0.7 mm.
TO was sputtered to form a transparent electrode having a thickness of 400 Å. Then, a polyimide (manufactured by Nippon Synthetic Rubber Co., trade name: Optomer A) is formed on each transparent electrode.
L-3046) was applied using a spinner and cured to form an alignment film having a thickness of 70 nm. In addition, an epoxy resin adhesive was applied to the bonded portion of the glass substrate by an ordinary method.

Next, a resin spacer ball having a diameter of 1.5 μm was sprayed on the alignment film so as to have a density of 100 balls / mm ² or less. The cell was produced by combining the adhesive parts by abutting and fixing them. Thus, the first and second cells were manufactured.

Next, 59% by weight of a nematic liquid crystal material (manufactured by Merck, trade name: E-48) and 41% by weight of a chiral substance (manufactured by Merck, trade name: CB-15) were mixed, and the right circle was mixed. A first liquid crystal material that selectively reflects polarized light was manufactured. Also, 65% by weight of the nematic liquid crystal material E-48 was used.
And 35% by weight of a chiral substance (manufactured by Merck, trade name: S-811) and a second material that selectively reflects left circularly polarized light.
Was prepared.

Next, the first and second liquid crystal materials were respectively injected into the first and second cells by a conventional method. Lastly, a separating member 3 is formed by filling a matching oil having a refractive index substantially equal to that of glass between the first cell and the second cell to form an air space (the first cell and the second cell). The light reflection at the glass interface by the layer formed between them is reduced.
Thus, a liquid crystal display device according to the present invention having the configuration shown in FIG. 1 was manufactured.

For this liquid crystal display device, the reflectance and the contrast were examined. The results are shown in Table 1 below.
The reflectivity and the contrast were measured using a luminance meter (trade name: BM-7, manufactured by Topcon Corporation) installed in the normal direction of the element by allowing light from a halogen light source to enter from the front of the cell. The voltage required for driving at this time was about 20V.

Example 2 First and second cells were manufactured in the same manner as in Example 1. Next, 59% by weight of the nematic liquid crystal material E-48 and 41% by weight of the chiral substance CB-15 are mixed to form a first material for selectively reflecting right circularly polarized light.
Was prepared. Further, the nematic liquid crystal material E-
48 and 61% by weight of the chiral substance CB-15 were mixed to prepare a second liquid crystal material that selectively reflects right circularly polarized light.

Next, the first and second liquid crystal materials were respectively injected into the first and second cells by a conventional method. Finally, between the first cell and the second cell, the selective reflection center wavelength (570 nm) of the lower second liquid crystal material and the accompanying light between the ordinary light component and the extraordinary light component in the wavelength region. An optical compensating element capable of shifting the phase difference of about half a wavelength λ / 2 is sandwiched. Thus, a liquid crystal display device of the present invention having the configuration shown in FIG. 2 was manufactured.

With respect to this liquid crystal display device, the reflectance and the contrast were examined in the same manner as in Example 1. The results are shown in Table 1 below. The voltage required for driving at this time was 18V.

Example 3 ITO was sputtered on two glass substrates having a thickness of 0.7 mm to form a transparent electrode having a thickness of 400 Å. Then, a polyimide optomer AL-3046 was placed on each transparent electrode.
Is applied using a spinner and cured to a thickness of 70 n.
m of alignment film was formed. In addition, an epoxy resin adhesive was applied to the bonded portion of the glass substrate by an ordinary method.

Next, resin spacer balls having a diameter of 3 μm were sprayed on the alignment film so as to have a density of 50 balls / mm ² or less. Next, a polyamic acid solution having a concentration of 10% by weight is spread on a water surface to form a thin film having a thickness of 1 μm. The thin film is sandwiched between the thin films, and the epoxy resin of the two glass substrates is arranged such that the alignment films face each other. A cell including the first and second regions was produced by combining the adhesive portions by abutting and fixing them.

Next, the nematic liquid crystal material E-48
9% by weight and 41% by weight of the chiral substance CB-15 were mixed to prepare a first liquid crystal material which selectively reflects right-handed circularly polarized light. A second liquid crystal material that selectively reflects left circularly polarized light was produced by mixing 65% by weight of the nematic liquid crystal material E-48 and 35% by weight of the chiral substance S-811.

Next, the first and second liquid crystal materials were injected into the first and second regions of the cell, respectively, by a conventional method. Thus, a liquid crystal display device according to the present invention having the configuration shown in FIG. 3 was manufactured. With respect to this liquid crystal display element, the reflectance and the contrast were examined in the same manner as in Example 1. The results are shown in Table 1 below.

Example 4 Two glass substrates having transparent electrodes were produced in the same manner as in Example 3. Then, a polyimide optomer AL-30 was placed on each transparent electrode.
46 is applied using a spinner and cured to a thickness of 7
An alignment film having a thickness of 0 nm was formed. Further, a photosensitive polyimide (provimid 412, manufactured by Fuji Hunt Co., Ltd.) is further placed thereon.
Is applied using a spinner and cured to a thickness of 1.5
A resist film having a height of 1.0 nm is formed at a predetermined position by performing exposure and development with a parallel exposure machine using a photomask.
A 5 μm spacer pillar was formed. In addition, an epoxy resin adhesive was applied to the bonded portion of the glass substrate by an ordinary method.

Next, a polyamic acid solution having a concentration of 10% by weight is spread on a water surface to form a thin film having a thickness of 1 μm, and the two thin glass substrates are sandwiched by the thin film so that the alignment films face each other. The cells including the first and second regions were fabricated by bringing the epoxy resin adhesive portions into contact with each other and fixing them.

Next, the nematic liquid crystal material E-48
9% by weight and 41% by weight of the chiral substance CB-15 were mixed to prepare a first liquid crystal material which selectively reflects right-handed circularly polarized light. In addition, a second liquid crystal material that selectively reflects left circularly polarized light was manufactured by mixing 72% by weight of the nematic liquid crystal material E-48 and 28% by weight of the chiral substance S-811.

Next, the first and second liquid crystal materials were respectively injected into the first and second regions of the cell by a conventional method. Thus, a liquid crystal display device according to the present invention having the configuration shown in FIG. 4 was manufactured. With respect to this liquid crystal display element, the reflectance and the contrast were examined in the same manner as in Example 1. The results are shown in Table 1 below.

Comparative Example A cell was fabricated in the same manner as in Example 1, and a liquid crystal material was injected into the cell by a conventional method. In this case, as a liquid crystal material, E-48 is 60% by weight, CB-
A mixture of 15 and 40% by weight was used. Thus, a conventional single-layer liquid crystal display device was manufactured. With respect to this liquid crystal display element, the reflectance and the contrast were examined in the same manner as in Example 1. The results are shown in Table 1 below.

[0082]

[Table 1]

As can be seen from Table 1, the liquid crystal display devices of the present invention (Examples 1 to 4) had high reflectivity and high contrast. On the other hand, the conventional liquid crystal display device (comparative example) had low reflectance and low contrast.

(Example 5) As shown in FIG.
05, a polyimide (Optomer AL-3) as an alignment film 114 is provided on the surface of the glass substrate 102 on which the pixel electrode 106 is formed and the black light absorbing film 110 is formed on the entire surface in contact with the liquid crystal material.
046: Nippon Synthetic Rubber Co., Ltd.) was cast to a thickness of 70 nm by a spinner.

Next, the alignment film 11 is similarly formed on the surface of the substrate 101, on which the common electrode 104 is formed on the entire surface, in contact with the liquid crystal material.
Polyimide (Optomer AL-3046: Nippon Synthetic Rubber (1)
Co., Ltd.) was cast with a spinner to a thickness of 70 nm.

Next, in order to bond the substrates 101 and 102, an epoxy adhesive was applied to predetermined positions of the substrates 101 and 102. Next, as a separating member 3, a glass substrate
Through holes 107 are etched at predetermined positions by etching.
Was formed, and the bumps were melt-filled on the through holes to establish electrical continuity between the front and back surfaces. Then, ITO was formed on both surfaces by sputtering, and the electrodes 108 and 109 were formed by etching.

Next, resin spacer balls having a diameter of 1.5 μm are scattered on the substrate surface so as to have a density of 100 balls / mm ² or less, and the substrate 101 and the separating member 103 are overlapped with the pixel electrodes 106 and the electrodes 109 and 108. And the substrate 102.

The liquid crystal material forming the first liquid crystal layer 117 is a nematic liquid crystal material E48 (manufactured by MERCK) 59
wt%, chiral substance CB15 (manufactured by MERCK) 41
A liquid crystal material mixed with wt% was used. The liquid crystal material forming the second liquid crystal layer 118 is a nematic liquid crystal E48.
72% by weight (manufactured by MERCK), chiral substance S811
A liquid crystal material mixed with 28 wt% (manufactured by MERCK) was used.

At this time, the first liquid crystal layer 117 selectively reflected right circularly polarized light, and the second liquid crystal layer 118 selectively reflected left circularly polarized light. The voltage required for driving at this time was 20V.

(Embodiment 6) As shown in FIG.
05, a polyimide (Optomer AL-3) as an alignment film 114 is provided on the surface of the glass substrate 102 on which the pixel electrode 106 is formed and the black light absorbing film 110 is formed on the entire surface in contact with the liquid crystal material.
046: Nippon Synthetic Rubber Co., Ltd.) was cast to a thickness of 70 nm by a spinner.

Next, the alignment film 11 is similarly formed on the surface of the substrate 101 having the common electrode 104 formed on the entire surface and in contact with the liquid crystal material.
Polyimide (Optomer AL-3046: Nippon Synthetic Rubber (1)
Co., Ltd.) was cast with a spinner to a thickness of 70 nm.

Next, in order to bond the substrates 101 and 102, an epoxy adhesive was applied to predetermined positions of the substrates 101 and 102. Next, as a separating member 103, a through hole 1 is formed on a resin substrate by etching at a predetermined position.
07, and the bumps are melt-filled on the through holes to establish electrical continuity between the front and back surfaces. Then, ITO is formed on both surfaces by sputtering and the electrodes 108 and 109 are etched.
Was formed. At this time, the separation member 103 is set so that the selective reflection center wavelength of the second liquid crystal layer 118 is 570 nm, and the phase of the ordinary light component and the extraordinary light component of the light in the wavelength region accompanying this is approximately λ / 2
A resin substrate that can be shifted was used. In this case, the light passing through the separating member 103 converts right circularly polarized light into left circularly polarized light and converts left circularly polarized light into right circularly polarized light.

Next, a resin spacer ball having a diameter of 1.5 μm is sprayed on the substrate surface so as to have a density of 100 balls / mm ² or less, and the substrate 101 and the separating member 103 are overlapped with the pixel electrodes 106 and the electrodes 109 and 108. And the substrate 102.

The liquid crystal material forming the first liquid crystal layer 117 is a nematic liquid crystal material E48 (manufactured by MERCK) 59
wt%, chiral substance CB15 (manufactured by MERCK) 41
A liquid crystal material mixed with wt% was used. The liquid crystal material forming the second liquid crystal layer 118 is a nematic liquid crystal E48.
(MERCK) 61wt%, Chiral substance CB15
A liquid crystal material mixed with 39 wt% (manufactured by MERCK) was used.

At this time, the first liquid crystal layer 117 selectively reflects the right-handed circularly polarized light, and the second liquid-crystal layer 118 reflects the right-handed circularly polarized light in which the left-handed circularly polarized light is compensated by the phase compensation formed in the separation layer. Was selectively reflected. At this time, the voltage required for driving was 18V.

Table 2 shows the display characteristics of the liquid crystal display devices of Examples 5 and 6 prepared as described above. For comparison, the display characteristics of a display element having a single-layer structure without an independent multilayer structure are also shown.

[0097]

[Table 2]

(Embodiment 7) As shown in FIG.
Photosensitive polyimide (Fluoromit 412: manufactured by Fuji Hunt Co.) was formed to a thickness of 2 μm on the surface of the glass substrate 102 on which the black light absorbing film 110 was formed on the entire surface of the glass substrate 102.

Next, after pre-baking the substrate, exposure was performed through a photomask by a parallel exposure machine (Nikon: PLA-501), and development and rinsing steps were performed to form pillars for spacers.

Next, as an alignment film 114 on this substrate,
Photosensitive polyimide (Optomer AL-3046: Nippon Synthetic Rubber Co., Ltd.)
) Was cast by a spinner to a thickness of 70 nm.
Next, polyimide (Ottomer AL-3046: Nippon Synthetic Rubber Co., Ltd.) is similarly used as the alignment film 111 on the surface of the substrate 101 having the common electrode 104 formed on the entire surface and in contact with the liquid crystal material.
It was cast with a spinner to a thickness of nm.

Next, in order to bond the substrates 101 and 102, an epoxy adhesive was applied to predetermined positions of the substrates 101 and 102. Next, a thin film having anisotropic conductive properties is formed as the separating member 103. Here, it was formed using a polysilane film described below.

[0102]

Embedded image

In the formula, R 1, R 2, R 3 and R 4 are each independently selected from the group consisting of H-substituted or unsubstituted aliphatic hydrocarbon residues, alicyclic hydrocarbon residues, and aromatic hydrocarbon residues. It is a group selected, and n and m are integers.

This polysilane was dissolved in an organic solvent and applied on a suitable substrate to a thickness of 20 μm by spin coating. Ethanol was used as a solvent. Next, a transparent conductive film (ITO) having a thickness of 100 nm was formed on the surface of the polysilane film thus formed by a sol-gel method. Subsequently, using a photomask, at an interval of 5 μm, 5
A μm × 5 μm square pattern was formed on the polysilane film.

At this time, it is preferable that the irradiation amount of the ultraviolet light applied to the polysilane film is about 1 to 10 J / cm ² . The exposed portion changes to a porous polysiloxane by this treatment.

After the exposure, the porous polysiloxane portion is doped with ITO by annealing at 80 to 120 ° C. Next, the anisotropic conductive film can be formed by removing the ITO remaining on the surface by etching. At this time, the difference between the resistance value in the film thickness direction and the film surface direction of the anisotropic conductive film was about 10 ⁶ .

Next, a cell was prepared by combining the substrate 101, the separating member 103 made of the anisotropic conductive film prepared in the above-described process, and the substrate 102. As a liquid crystal material forming the first liquid crystal layer 117, a liquid crystal material obtained by mixing 59 wt% of a nematic liquid crystal material E48 (manufactured by MERCK) and 41 wt% of a chiral substance CB15 (manufactured by MERCK) is used. Also the second
The liquid crystal material forming the liquid crystal layer 118 is 72 wt% of nematic liquid crystal E48 (manufactured by MERCK) and chiral substance S
A liquid crystal material mixed with -811 (manufactured by MERCK) 28 wt% was used.

At this time, the first liquid crystal layer 117 selectively reflected right circularly polarized light, and the second liquid crystal layer 118 selectively reflected left circularly polarized light. The voltage required for driving at this time is about 3
It was 0V.

(Embodiment 8) As shown in FIG.
On a surface of the glass substrate 102 on which the black light absorbing film 110 was formed on the pixel electrode 106 and the entire surface of the glass substrate 102, photosensitive polyimide (Fluoromit 412: manufactured by Fuji Hunt) was formed to a thickness of 1.5 μm.

Next, after pre-baking the substrate, exposure was carried out through a photomask by a parallel exposure machine (Nikon: PLA-501), followed by development and rinsing steps to form pillars for spacers.

Next, as an alignment film 114 on this substrate,
Polyimide (Oppomer AL-3046: Nippon Synthetic Rubber Co., Ltd.)
It was cast with a spinner to a thickness of 0 nm. Next, polyimide (Ottomer AL-3046: Nippon Synthetic Rubber Co., Ltd.) is similarly spin-coated to a thickness of 70 nm on the surface of the substrate 101 having the common electrode 104 formed on the entire surface and in contact with the liquid crystal material. Cast by.

Next, an epoxy adhesive was applied to predetermined positions of the substrates 101 and 102 in order to bond the substrates 101 and 102 together. Next, a thin film having anisotropic conductive properties is formed as the separating member 103. Here, it was formed using a polysilane film represented by the formula (1). The polysilane was dissolved in an organic solvent, and a laminated thin film of a monomolecular film having an orientation was formed on an appropriate water surface with a thickness of 20 μm using an LB method, and developed on an appropriate substrate. Ethanol was used as a solvent.

Next, a transparent conductive film (ITO) having a thickness of 100 nm was formed on the surface of the polysilane film thus formed by a sol-gel method. Subsequently, a 5 μm × 5 μm square pattern was formed on the polysilane film at an interval of 5 μm using a photomask.

At this time, it is preferable that the irradiation amount of the ultraviolet light applied to the polysilane film is about 1 to 10 J / cm ² .
The exposed portion changes to a porous polysiloxane by this treatment.

By the function of the retardation plate, the porous polysiloxane portion is doped with ITO by annealing at 80 ° C. to 120 ° C. after the first exposure. Next, an anisotropic conductive film was formed by removing ITO remaining on the surface by etching.

At this time, the difference between the resistance value in the film thickness direction and the resistance value in the film surface direction of the anisotropic conductive film was about 106. Next, the substrate 101,
Separation member 10 made of anisotropic conductive film prepared in the above step
3. A cell was prepared by combining the substrate 102.

The liquid crystal material forming the first liquid crystal layer 117 is a nematic liquid crystal material E48 (manufactured by MERCK) 59
wt%, chiral substance CB15 (manufactured by MERCK) 41
A liquid crystal material mixed with wt% was used. The liquid crystal material forming the second liquid crystal layer 18 is a nematic liquid crystal E48 (M
ERCK) 72wt%, Chiral substance S-811
A liquid crystal material mixed with 28 wt% (manufactured by MERCK) was used.

Table 2 shows the display characteristics of the liquid crystal display devices of Examples 7 and 8 prepared as described above. For comparison, the display characteristics of a display element having a single-layer structure without an independent multilayer structure are also shown. The voltage required for driving at this time was 32V.

[0119]

[Table 3]

Here, as shown in FIG. 5, the first liquid crystal layer 1
17, if there is a region where the electrode 109 is not formed, for example, a region on the TFT 105, the first liquid crystal layer 1
The liquid crystal molecules existing in this portion 17 do not change direction even when an electric field is applied, and there is a problem that light cannot be controlled. The presence of such a portion is not preferable in terms of display characteristics.

Therefore, as shown in FIG.
The black insulating layer pattern 119 is formed in a portion where no 09 is formed.
Is preferably formed, and this portion is optically hidden. This pattern may be formed between the lower electrodes 109.

Here, in order to form the black insulating layer pattern 119, the space between the electrode 108 and the black insulating layer pattern 119 is completely covered in order to completely cover the space between the adjacent electrodes 108 and to secure a margin for alignment. It is necessary to provide an overlapping portion having a width of several microns on one side. It is better to eliminate the overlap portion as much as possible to reduce the pixel area. Preferably, the black insulating layer pattern 119 is formed between the electrodes without this overlap.

Accordingly, the black insulating layer pattern 1 is described below.
The method of forming the electrodes 19 in a self-aligned manner between the electrodes 108 will be described. 8 to 16 are cross-sectional views of the intermediate layer 103 in each step in the method of forming the above-described black insulating layer pattern 119 in a self-aligned manner.

First, an insulating transparent substrate 103 made of glass having a contact hole 107 filled with a conductive material
Is prepared, and a black insulating layer is deposited on the substrate 103 by using a CVD method or a spin coating method, and is patterned to form a black insulating layer pattern 119 (FIG. 8).

Next, a positive photoresist film 20 is applied on the substrate 103 on the side where the black insulating layer pattern 119 is formed, and exposure is performed from the back surface (FIG. 9). Next, by developing the exposed substrate 103, the photoresist film 120 is left only on the black insulating layer pattern 119 (FIG. 10).

Next, 100
A transparent conductive material 108 having a thickness of about nm is deposited by, for example, an ITO film (FIG. 11). Next, by dissolving and removing the pattern of the photoresist film 120 in this state, the ITO film 108 on the photoresist film 120 is simultaneously removed, and the black insulating layer pattern 119 and the electrode 108 are removed.
Are formed in a self-aligned manner (FIG. 12).

Next, a positive photoresist film 121 is applied to the surface of the substrate 103 opposite to the surface on which the black insulating layer pattern 119 is formed, and exposure is performed from the surface (FIG. 13).

Next, this substrate is developed to form a pattern of the photoresist film 121 (FIG. 14). next,
Subsequently, a transparent conductive material 109 serving as an electrode having a thickness of about 100 nm is formed of, for example, an ITO film by a sputtering method or the like (FIG. 15).

Next, in this state, the photoresist film 121 is formed.
The transparent conductive material 109 on the photoresist film 121 is also removed by dissolving and removing the pattern of
The black insulating layer pattern 119 and the electrode 109 can be formed in a self-aligned manner (FIG. 16).

In this manner, the intermediate electrodes 108 and 109 made of a transparent conductive material and the black insulating layer pattern 119 can be formed on the upper and lower surfaces of the insulating transparent substrate 103 in alignment. At this time, the intermediate electrodes 108 and 109 are electrically connected together by the contact hole 107 filled with the conductive material. Although the photoresist film pattern 120 is formed using the black insulating layer pattern 119 as a mask as shown in FIGS. 8 to 10, it may be formed by another method. 17 and 18 show examples. First, after a black insulating layer 119 is deposited on the insulating transparent substrate 103, a photoresist film 120 is applied (FIG. 17). Next, the photoresist film 120 is patterned using a normal PEP method. Using the pattern of the photoresist film 120 as a mask, the black insulating film 119 is patterned (FIG. 18). Subsequent steps may be performed in the same manner as described above.

In the above-described method of forming the separating member, the transparent electrode layer pattern on the side where the black insulating layer pattern 119 is formed, of the transparent electrode layer patterns 8 and 9 formed on the upper surface and the lower surface of the insulating transparent substrate 103, is used. However, it is needless to say that a similar structure can be obtained by first forming the transparent electrode layer pattern on the side opposite to the side on which the black insulating layer pattern 119 is formed. Absent.

By using the above method, a separating member having electrodes made of a transparent conductive material on the upper and lower surfaces of the insulating transparent substrate can be formed in a self-aligned manner with a black insulating layer pattern between the electrodes.

As described above, by providing the separation member having the through hole between the first liquid crystal layer and the second liquid crystal layer, the electrodes formed on both surfaces of the separation member can be electrically connected. No voltage drop is involved. A similar effect can be obtained by forming this separating member with an anisotropic conductive film.

[0134]

According to the present invention, a reflection type liquid crystal display device having a high reflectance can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of a reflective liquid crystal display device of the present invention.

FIG. 2 is a sectional view of a reflective liquid crystal display device of the present invention.

FIG. 3 is a sectional view of a reflective liquid crystal display device of the present invention.

FIG. 4 is a sectional view of a reflective liquid crystal display device of the present invention.

FIG. 5 is a sectional view of a reflective liquid crystal display device of the present invention.

FIG. 6 is a sectional view of a reflective liquid crystal display device of the present invention.

FIGS. 7A and 7B are cross-sectional views in each step for explaining a step of forming a separation member used in the reflection type liquid crystal display element of the present invention.

FIG. 8 is a cross-sectional view in each step for explaining a step of forming a separation member used in the reflective liquid crystal display element of the present invention.

FIG. 9 is a cross-sectional view in each step for explaining a step of forming a separation member used in the reflective liquid crystal display element of the present invention.

FIG. 10 is a cross-sectional view of each step for explaining a step of forming a separation member used in the reflective liquid crystal display element of the present invention.

FIG. 11 is a cross-sectional view in each step for explaining a step of forming a separation member used in the reflective liquid crystal display element of the present invention.

FIG. 12 is a cross-sectional view in each step for explaining a step of forming a separation member used in the reflective liquid crystal display element of the present invention.

FIG. 13 is a cross-sectional view in each step for describing a step of forming a separation member used in the reflective liquid crystal display element of the present invention.

FIG. 14 is a cross-sectional view in each step for explaining a step of forming a separation member used in the reflective liquid crystal display element of the present invention.

FIG. 15 is a cross-sectional view in each step for describing a step of forming a separation member used in the reflective liquid crystal display element of the present invention.

FIG. 16 is a cross-sectional view in each step for describing a step of forming a separation member used in the reflective liquid crystal display element of the present invention.

FIG. 17 is a cross-sectional view in each step for explaining a step of forming a separation member used in the reflective liquid crystal display element of the present invention.

FIG. 18 is a cross-sectional view in each step for describing a step of forming a separation member used in the reflective liquid crystal display element of the present invention.

FIG. 19 is a diagram showing the relationship between the central wavelengths of selective reflection in the upper layer and the lower layer of the reflective liquid crystal display device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... 1st cell 2 ... 2nd cell 3 ... Separation member which does not have optical rotation 4 ... Separation member which has optical rotation 11, 12, 21, 22 ... Transparent substrate 13 , 14, 23, 24 ... electrode layer 15, 16, 25, 26 ... alignment film 17, 27 ... spacer ball 18, 28 ... liquid crystal material 31 ... thin film 32 ... first Area 33 ... second area 34 ... spacer pillar 101 ... substrate 102 ... substrate 103 ... separation member 104 ... common electrode 105 ... TFT 106 ... pixel electrode 107 ... through-hole 108 ... upper electrode of separation member 109 ... lower electrode of separation member 110 ... black absorption layer 111, 112, 113, 114 ... alignment film 115, 116 ... liquid crystal Material 117: First liquid crystal layer 118 ... second liquid crystal layer 119 ... black insulating film 120 and 121 ... photoresist

 ──────────────────────────────────────────────────続 き Continued on front page (72) Inventor Miki Mori 33 Shinisogocho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside Toshiba Production Technology Research Institute (72) Inventor Yoshihisa Mizutani 33, Shinisogocho, Isogo-ku, Yokohama-shi, Kanagawa Address: Toshiba Production Technology Laboratory Co., Ltd. (72) Inventor: Seizaburo Shimizu 33, Shinisogo-cho, Isogo-ku, Yokohama-shi, Kanagawa Pref.

Claims (17)

[Claims] A first liquid crystal layer provided on the substrate; a second liquid crystal layer provided on the first liquid crystal layer; a first liquid crystal layer provided on the substrate; A second liquid crystal layer, and a separating member provided between the first liquid crystal layer and the second liquid crystal layer to separate the first liquid crystal layer and the second liquid crystal layer;
The first and second liquid crystal layers are formed of a liquid crystal material that has the same twist direction and selectively reflects circularly polarized light in the same direction, and the separation layer has optical rotation. Display element. 2. The reflection type liquid crystal display device according to claim 1, wherein said first and second liquid crystal layers have a twist pitch p1 and a second pitch.
The liquid crystal has a twist pitch p2, and is formed of a liquid crystal material in which the twist direction is the same direction.
A wavelength width Δn · p1 (Δn =
ne1-no1: ne1 is the refractive index of the extraordinary light component of the first liquid crystal layer; A reflective liquid crystal display device comprising: A substrate having a pixel electrode formed on a surface thereof; a first liquid crystal layer provided on the substrate; a second liquid crystal layer provided on the first liquid crystal layer; A second liquid crystal layer, and a separating member provided between the first liquid crystal layer and the second liquid crystal layer to separate the first liquid crystal layer and the second liquid crystal layer;
The first and second liquid crystal layers have the same twist direction,
The liquid crystal material is made of a liquid crystal material that selectively reflects circularly polarized light in the same direction.
A reflection type liquid crystal display device, wherein λ is 30 nm <３０λ <100 nm. 4. A substrate having a pixel electrode formed on a surface thereof; a first liquid crystal layer provided on the substrate; a second liquid crystal layer provided on the first liquid crystal layer; A second liquid crystal layer, and a separating member provided between the first liquid crystal layer and the second liquid crystal layer to separate the first liquid crystal layer and the second liquid crystal layer;
The first and second liquid crystal layers have a different twist direction and are made of a liquid crystal material that selectively reflects circularly polarized light in different directions, and have a selective reflection center wavelength λ of the liquid crystal material of the first liquid crystal layer.
A reflection type liquid crystal display device characterized in that a difference Δλ between 1 and a selective reflection wavelength λ2 of the liquid crystal material of the second liquid crystal layer is 30 nm <Δλ <100 nm. 5. A substrate having a pixel electrode formed on a surface thereof; a first liquid crystal layer provided on the substrate; a second liquid crystal layer provided on the first liquid crystal layer; A second liquid crystal layer, and a separating member provided between the first liquid crystal layer and the second liquid crystal layer to separate the first liquid crystal layer and the second liquid crystal layer;
The separation member has a thickness of 1 μm or less, and has a thickness of 400 nm.
A reflective liquid crystal display device comprising a material capable of transmitting light having a wavelength of 650 nm. 6. A substrate having a pixel electrode formed on a surface thereof, a first liquid crystal layer made of a chiral nematic liquid crystal material provided on the substrate, and a chiral nematic liquid crystal provided on the first liquid crystal layer. A second liquid crystal layer formed of: a counter electrode formed on the second liquid crystal layer;
A separating member provided between the first liquid crystal layer and the second liquid crystal layer for separating the first liquid crystal layer and the second liquid crystal layer, and a first member formed on a surface of the separating member facing the first liquid crystal layer. And a second electrode formed on a surface of the separation member facing the second liquid crystal layer. The first electrode and the second electrode
Are electrically connected through through holes provided in the separation member, and simultaneously drive the first liquid crystal layer and the second liquid crystal layer by applying a voltage between the pixel electrode and the counter electrode. A reflective liquid crystal display device. 7. A substrate having a pixel electrode formed on a surface thereof; a first liquid crystal layer provided on the substrate; a second liquid crystal layer provided on the first liquid crystal layer; A counter electrode formed on the second liquid crystal layer, and a separating member provided between the first liquid crystal layer and the second liquid crystal layer to separate the first liquid crystal layer and the second liquid crystal layer; The separating member has anisotropic conductive properties, and the first liquid crystal layer and the second liquid crystal layer are simultaneously driven by applying a voltage between the pixel electrode and the counter electrode. Reflective liquid crystal display device. 8. The reflection type liquid crystal display device according to claim 7, wherein said first and second liquid crystal layers are made of a chiral nematic liquid crystal material. 9. The chiral nematic liquid crystal material is a mixed liquid crystal of a nematic liquid crystal and a chiral substance including a cholesteric liquid crystal, and has a twisted structure of 350 n.
9. The reflective liquid crystal display device according to claim 6, wherein the reflective liquid crystal display device reflects light having a wavelength of m to 650 nm. 10. A twisting direction of a chiral nematic liquid crystal material forming the first liquid crystal layer and a twisting direction of a chiral nematic liquid crystal material forming the second liquid crystal layer are the same direction. A second liquid crystal layer between the liquid crystal layer and the second liquid crystal layer;
9. A phase compensating layer for changing the circularly polarized light of light transmitted through the liquid crystal layer in the opposite direction.
The reflective liquid crystal display element as described in the above. 11. An average refractive index n of a chiral nematic liquid crystal material constituting said first liquid crystal layer as said phase compensation layer.
1 and a wavelength width Δn · p1 (Δn = ne1-) having a selective reflection wavelength center value λ1 determined by the pitch p1 of the twisted structure.
no1 +: ne1 is the refractive index of the extraordinary light component of the first liquid crystal layer, and no1 is the phase of the ordinary light component of the light of the first liquid crystal layer and the extraordinary light component, which are shifted by about a half wavelength. The reflective liquid crystal display device according to claim 10, wherein a possible optical film is used. 12. The reflection type liquid crystal display device according to claim 11, wherein said separation member is formed by bonding a glass substrate, and said optical film is sandwiched between said glass substrates. 13. A twisting direction of a chiral nematic liquid crystal material forming the first liquid crystal layer and a twisting direction of a chiral nematic liquid crystal material forming the second liquid crystal layer are opposite to each other. 10. The reflective liquid crystal display device according to claim 6, wherein the reflective liquid crystal display device is made of a film or glass that does not optically show optical rotation. 14. A first and a second member formed on the separating member.
13. The electrode of claim 6, which is formed for each pixel, is electrically independent of other pixels, and is in a floating state in which no charge enters and exits. Alternatively, the reflective liquid crystal display device according to item 13. 15. The device according to claim 6, wherein the first and second electrodes have the same or different surface areas.
8. The reflective liquid crystal display device according to 8, 9, 10, 11, 12, 13 or 14. 16. The second electrode may be larger than the surface area of the first electrode.
2. The electrode according to claim 1, wherein the surface area of the electrode is larger.
6. The reflective liquid crystal display device according to 5. 17. The difference Δλ between the selective reflection center wavelength λ1 of the chiral nematic liquid crystal material of the first liquid crystal layer and the selective reflection center wavelength λ2 of the chiral nematic liquid crystal material of the second liquid crystal layer is 30 nm <Δλ <100 nm. 6. The method of claim 6, 8, 9, 10, 11, 12, 1,
17. The reflective liquid crystal display device according to 3, 14, 15 or 16.