JPH10161105A - Liquid crystal device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce transmission light in a dark state and to improve the performance of a liquid crystal device by reducing scattered light caused by that a linear polarization incident on a color filter layer is polarization canceled. SOLUTION: A color ferroelectric liquid crystal device is provided with ferroelectric liquid crystal material 2 between two sheets of glass substrates 3, 4 arranged at a fixed interval through a speaker. Then color filter layer 5 is provided on the glass substrate 3, and the surface of the color filter layer 5 is covered by a faltering layer 6 consisting of material flattening the surface. Electrode structures 7, 8, barrier layers 9, 10 and oriented layers 11, 12 are provided on the inside surfaces of the glass substrates 3, 4. Further, a polarizing layer 16 is provided between the color filter layer 5 and the liquid crystal material 2 for suppressing that the light linearly polarized by a polarizer 14 is polarization canceled by the color filter layer 5 and reducing the transmission light in the dark state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal device, and more particularly, but not exclusively, to a ferroelectric liquid crystal device.

[0002]

2. Description of the Related Art A conventional surface-stable ferroelectric liquid crystal display device (hereinafter referred to as FLCD) is composed of two glass substrates in which a layer made of a chiral smectic phase ferroelectric liquid crystal material is arranged in parallel. It is a configuration sandwiched between. 2 above
Row electrodes and column electrodes are formed on the inner surface of the glass substrates so as to cross each other. The pixels corresponding to the intersections of the row electrodes and the column electrodes form an addressable matrix array.

Conventionally, in a selected pixel, a driving method of applying a strobe pulse and a data pulse to a row electrode and a column electrode has been used in order to switch liquid crystal molecules between bipolar states in which molecular orientations are different from each other. Since the above-mentioned bipolar state has different light transmission characteristics due to a difference in molecular orientation, if two polarizers are arranged so that their polarization axes are substantially orthogonal to each other and a liquid crystal material is arranged between them, a display in a display may be produced. Each pixel has a dark state or a bright state, depending on the state in which the molecule was previously switched.

Color F used for color display
In the case of an LCD, a color filter layer having blue, green, and red regions for each pixel of the cell may be provided on one of the two substrates.

[0005]

However, it is known that the above-mentioned conventional color filter layer has a property of depolarizing linearly polarized light incident on the color filter layer. In this case, the depolarized light is scattered, the transmitted light in the dark state increases, and the performance of the device is greatly deteriorated. As a result, there arises a problem that the display quality in the dark state is deteriorated and the contrast ratio is significantly lowered.

It is an object of the present invention to provide a means for substantially eliminating the scattering of depolarized light to reduce transmitted light in the dark.

[0007]

According to a first aspect of the present invention, there is provided a liquid crystal device, comprising: a liquid crystal material layer disposed between two substrates; and a liquid crystal material layer disposed between at least one of the two substrates. And a polarizing layer disposed between the color filter layer and the liquid crystal material layer to compensate for depolarization of linearly polarized light in the color filter layer, wherein the polarizing layer is aligned and polymerized. Characterized by comprising a molecular coating.

[0008] According to the above arrangement, the polarizing layer comprising the oriented and polymerized molecular coating and disposed between the color filter layer and the liquid crystal material layer compensates for depolarization of linearly polarized light in the color filter layer. . This reduces the scattering of the depolarized light, reduces the transmitted light in the dark state, and improves the performance of the device.

A liquid crystal device according to a second aspect is the liquid crystal device according to the first aspect, wherein the molecular coating is aligned by exposure to linearly polarized light.

According to a third aspect of the present invention, in the liquid crystal device according to the first or second aspect, the molecular film includes a carrier medium mixed with dye molecules, which is applied to at least one of the substrates. Features.

According to a fourth aspect of the present invention, in the liquid crystal device according to any one of the first to third aspects, a flattening layer is provided on the color filter layer. Is characterized by having a uniform thickness.

According to a fifth aspect of the present invention, in the liquid crystal device according to the fourth aspect, the refractive index of the flattening layer is substantially equal to the refractive index of the color filter layer.

According to a sixth aspect of the invention, there is provided a method of manufacturing a liquid crystal device.
A method for manufacturing a liquid crystal device, comprising: a liquid crystal material layer disposed between two substrates; and a color filter layer formed on at least one of the two substrates, wherein the color filter layer includes a liquid crystal material layer and a liquid crystal material layer. The method is characterized by including a step of forming a molecular film on a surface in contact with the film, and a step of orienting and polymerizing the molecular film to have a polarizing ability.

According to the above-described manufacturing method, a molecular film for compensating for depolarization of linearly polarized light in the color filter layer can be formed, and scattering of depolarized light can be prevented. As a result, a high-performance liquid crystal device with little transmitted light in a dark state can be provided.

According to a seventh aspect of the present invention, there is provided a method of manufacturing a liquid crystal device according to the sixth aspect, wherein the alignment treatment of the molecular film is performed by exposing with a linearly polarized light.

According to a eighth aspect of the present invention, in the method of the sixth or seventh aspect, in the step of forming the molecular film, a carrier medium containing a dye molecule is provided on at least one of the substrates. It is characterized by being applied.

According to a ninth aspect of the present invention, there is provided a method of manufacturing a liquid crystal device, comprising the steps of:
Forming a film having a uniform thickness composed of the color filter layer and the flattening layer by forming a flattening layer having a refractive index substantially equal to the refractive index of the color filter layer on the color filter layer. It is characterized by the following.

According to a tenth aspect of the present invention, there is provided a method of manufacturing a liquid crystal device.
The method according to any one of claims 6 to 8, further comprising a step of subjecting the color filter layer to a polishing treatment for planarizing the surface.

A liquid crystal device according to claim 11, further comprising a liquid crystal material layer disposed between two substrates, and a color filter layer formed on at least one of the two substrates, wherein the color filter layer Include molecules arranged so as to have a polarization ability, and the polarization ability of the molecules compensates for depolarization of the linearly polarized light incident on the color filter layer in the color filter layer.

According to the above configuration, depolarization of linearly polarized light in the color filter layer is prevented, and scattering of depolarized light can be reduced. As a result, a high-performance liquid crystal device with little transmitted light in a dark state can be provided.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG. FIG.
1 is a schematic sectional view of one pixel of an FLCD cell.

A color display device (liquid crystal device) provided with the FLCD cell 1 has a smectic between two glass substrates 3.4 (substrates) arranged at intervals by a spacer (not shown) so as to be parallel to each other. In this configuration, a phase ferroelectric liquid crystal material 2 (liquid crystal material layer) is sandwiched. The thickness of the glass substrates 3.4 is usually 1.1 mm, and the distance d between the glass substrates 3.4 is usually 1.5 μm.

The color filter layer 5 formed on the glass substrate 3 has three regions of blue (B), green (G) and red (R) per pixel of the cell. Further, by covering the color filter layer 5 with a flattening layer 6 made of a material for flattening irregularities, a substantially flat surface is formed. The overall thickness of the layer including the color filter layer 5 and the flattening layer 6 is generally 1 μm.

Electrode structures 7, 8 made of transparent ITO (Indium tin oxide), barrier layers 9, 10, and alignment layers 11
12 are provided in this order on the surfaces facing the inside of the glass substrates 3 and 4. Electrode structure 7, barrier layer 9,
And three layers stacked in the order of the alignment layer 11 and the electrode structure 8,
The three layers that are stacked in the order of the barrier layer 10 and the alignment layer 12 generally have a thickness of 0.4 μm, respectively.

Each of the electrode structures 7 and 8 has a configuration in which a plurality of electrode tracks are arranged in parallel with each other. The electrode structure 7 forms a row and the electrode structure 8 forms a column orthogonal to the row, and the intersection of the row and the column becomes a pixel. When addressing a pixel, appropriate strobe and data pulses may be applied to appropriate electrodes that intersect at the pixel in the electrode structures 7,8.

The electrode structure is not limited to the above-described matrix-like structure. In addition, for example, in the case of an (r, θ) display, the electrode structure may be formed in a radially curved track shape. In the case of an alphanumeric display, it may be formed in a segment shape.

The cell 1 has a structure for polarizing transmitted light. Generally, a polarizer 14 and an analyzer 15 are arranged on both sides of the cell 1. Alternatively, a polarizer may be provided on one side of the cell 1 and a polarizing dye may be mixed into the liquid crystal material.

However, in such a configuration,
It is known that the quality of the dark state is particularly deteriorated because the linearly polarized light incident on the color filter layer 5 is easily depolarized in the color filter layer 5. this is,
The minute irregularities on the surface of the color filter layer 5 cause a minute change in the thickness of the color filter layer 5 on the order of 10 μm, and as a result, the transmission characteristics of light passing through the color filter layer 5 become non-uniform, By the reflection and refraction of light at the interface between the color filter layer 5 and the flattening layer 6,
It is believed that light scattering is very significant.

When depolarization occurs in the color filter layer 5 as described above, the transmitted light in the pixel in the dark state increases as compared with the case where there is little or no depolarization, and the performance of the device deteriorates. Would.

Therefore, in order to improve the performance of the device,
Some examples for reducing the linearly polarized light from being depolarized in the color filter layer 5 to reduce the transmitted light in the dark state of the device are given below.

The first example has a configuration in which a polarizing layer having both functions of a color filter and a polarizer is provided on the color filter layer 5. Such a polarizing layer can be realized, for example, as a flat colored Polaroid (registered trademark) layer. Since the incident light is polarized when passing through the polaroid layer (polarizing layer), depolarization in the color filter layer 5 is compensated. In this case, since the color polaroid layer has a polarization characteristic, it is not necessary to separately provide a polarizer. When the polaroid layer is formed sufficiently flat, the flattening layer 6 is formed.
Can be omitted. First, a polaroid layer is formed on a glass substrate. Then, in order to form a plurality of color filters of different colors on the polaroid layer, the photoresist is selectively removed by a method similar to a conventional color filter. Can also be deposited.

In the second example, in order to ensure that the light incident on the liquid crystal material 2 is linearly polarized, the liquid crystal material 2 is placed between the color filter layer 5 and the liquid crystal material 2. Layer 16 that linearly polarizes the light transmitted toward
Is inserted. By providing such a polarizing layer 16, the depolarized light is not scattered, so that the transmitted light in the dark state is reduced, and the performance in the dark state is improved.

The polarizing layer 16 for polarizing the light transmitted through the color filter layer 5 is formed by first coating a carrier medium containing dye molecules on the color filter layer 5 by spin coating. It is formed by orienting the molecules in one direction by exposure to linearly polarized light.

The dye molecules of the molecular coating may be organic dye molecules such as azo dyes and polyiodine compound salts. Further, in order to give the dye molecules a polarizing ability, in addition to the linearly polarized light exposure as described above, it is also possible to use a method such as performing a rubbing treatment to orient the molecules in a predetermined direction. .

The polarizing layer 16 is formed of a semi-solid liquid crystal material such as a smectic A phase or a smectic B phase, and the molecules of the liquid crystal material are oriented in a desired direction by, for example, rubbing. It may have a polarization ability. After such a polarization treatment, the molecules of the polarization layer 16 may be polymerized by, for example, ultraviolet irradiation or heat treatment.

As a third example, the color filter layer 5 may be polished in order to flatten the rough surface of the color filter layer 5 and reduce the depolarization characteristics of the color filter layer 5.

If the color filter layer 5 is sufficiently flat, the flattening layer 6 can be omitted. When the flattening layer 6 is provided, the color filter layer 5
In order to prevent the incident light to be depolarized, and to realize a uniform thick film having a single refractive index, the refractive index of the flattening layer 6 is substantially the same as that of the color filter layer 5. The rate may be good.

As described above, by reducing the depolarization caused by the color filter layer 5, the performance of a wide range of devices including such a color filter layer 5 can be improved.

Although the present invention has been described with reference to an example in which the present invention is applied to a color display device including an FLCD cell, the present invention relates to an arbitrary color liquid crystal display device having a configuration in which polarized light is analyzed after passing through a color filter. It is possible to apply to. Further, the present invention can be applied not only to a conventional color display device employing a combination of a polarizer and an analyzer, but also to a device using a polarizing dye or a mirror instead of the analyzer. It is possible to apply.

[0040]

As described above, the liquid crystal device according to the first aspect of the present invention comprises a liquid crystal material layer disposed between two substrates,
A color filter layer formed on at least one of the two substrates, and a polarizing layer disposed between the color filter layer and the liquid crystal material layer to compensate for depolarization of linearly polarized light in the color filter layer; The polarizing layer is composed of an oriented and polymerized molecular film.

Thus, the depolarization of the linearly polarized light in the color filter layer is compensated for by the polarizing layer.
Scattering of the depolarized light is reduced and transmitted light in the dark state is reduced. As a result, there is an effect that the performance of the liquid crystal device can be improved.

The liquid crystal device according to the second aspect has a configuration in which the molecular coating is aligned by exposure to linearly polarized light.

Thus, a polarizing layer that compensates for depolarization of linearly polarized light in the color filter layer can be realized. As a result, there is an effect that the transmitted light in the dark state is reduced and the performance of the liquid crystal device can be improved.

According to a third aspect of the present invention, in the liquid crystal device, the molecular coating is:
This is a configuration including a carrier medium mixed with dye molecules applied to at least one of the substrates.

Thus, a polarizing layer that compensates for depolarization of linearly polarized light in the color filter layer can be realized. As a result, there is an effect that the transmitted light in the dark state is reduced and the performance of the liquid crystal device can be improved.

According to a fourth aspect of the present invention, a flattening layer is provided on the color filter layer, and the film composed of the color filter layer and the flattening layer has a uniform thickness.

Thus, the depolarization of the linearly polarized light in the color filter layer is compensated, and the transmitted light in the dark state can be reduced. As a result, there is an effect that the performance of the liquid crystal device can be improved.

In the liquid crystal device according to the fifth aspect, the refractive index of the flattening layer is substantially equal to the refractive index of the color filter layer.

Thus, the depolarization of the linearly polarized light in the color filter layer is compensated, and the transmitted light in the dark state can be further reduced. As a result, there is an effect that the performance of the liquid crystal device can be improved.

The method for manufacturing a liquid crystal device according to claim 6 is characterized in that
A method for manufacturing a liquid crystal device, comprising: a liquid crystal material layer disposed between two substrates; and a color filter layer formed on at least one of the two substrates, wherein the color filter layer includes a liquid crystal material layer and a liquid crystal material layer. A step of forming a molecular film on the surface in contact with the film, and a step of orienting and polymerizing the molecular film to have a polarizing ability.

Thus, a molecular film for compensating for depolarization of linearly polarized light in the color filter layer can be formed, and scattering of depolarized light can be prevented.
As a result, there is an effect that a high-performance liquid crystal device with little transmitted light in a dark state can be provided.

In the method of manufacturing a liquid crystal device according to the present invention, the alignment treatment of the molecular film is performed by exposing with a linearly polarized light.

Thus, it is possible to realize a molecular film for compensating depolarization of linearly polarized light in the color filter layer. As a result, it is possible to provide a high-performance liquid crystal device in which scattering of depolarized light is small and transmitted light in a dark state is small.

In the method of manufacturing a liquid crystal device according to the present invention, in the step of forming a molecular film, a carrier medium containing a dye molecule is applied to at least one of the substrates.

As a result, a molecular film for compensating for depolarization of linearly polarized light in the color filter layer can be realized. As a result, it is possible to provide a high-performance liquid crystal device in which scattering of depolarized light is small and transmitted light in a dark state is small.

According to a ninth aspect of the present invention, a flattening layer having a refractive index substantially equal to the refractive index of the color filter layer is formed on the color filter layer.
Forming a film having a uniform thickness comprising a color filter layer and a planarizing layer.

Thus, the film having a uniform thickness composed of the color filter layer and the flattening layer can compensate for the depolarization of the linearly polarized light in the color filter layer and reduce the scattering of the depolarized light. As a result, there is an effect that a high-performance liquid crystal device with little transmitted light in a dark state can be provided.

The method for manufacturing a liquid crystal device according to claim 10 is
A step of subjecting the color filter layer to a polishing treatment for flattening the surface.

Thus, depolarization of linearly polarized light in the color filter layer is prevented, and scattering of depolarized light can be reduced. As a result, there is an effect that a high-performance liquid crystal device with little transmitted light in a dark state can be provided.

A liquid crystal device according to claim 11, comprising a liquid crystal material layer disposed between two substrates, and a color filter layer formed on at least one of the two substrates, wherein the color filter layer Contains molecules arranged so as to have a polarization ability, and the polarization ability of the molecules compensates for depolarization of the linearly polarized light incident on the color filter layer in the color filter layer.

Thus, the depolarization of the linearly polarized light in the color filter layer is prevented, and the scattering of the depolarized light can be reduced. As a result, there is an effect that a high-performance liquid crystal device with little transmitted light in a dark state can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a schematic configuration of an FLCD cell according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 FLCD cell 2 Ferroelectric liquid crystal material (liquid crystal material layer) 3.4 Glass substrate 5 Color filter layer 6 Flattening layer 16 Polarization layer 14 Polarizer 15 Analyzer

──────────────────────────────────────────────────の Continuation of front page (51) Int.Cl. ⁶ Identification code FIG09F 9/35 321 G09F 9/35 321 (71) Applicant 390040604 United Kingdom GOVERNMENT OF THE UNITED KINGDOM OF GREAT BRITAIN BRAND AND AND NORTHERN IRELAND Hampshire GU 140 UK Elx Farnborough Iveley Road (No Address) Defence Evaluation and Researchers UK 72 , Us Tarsier W. 135 E.D., Malvern, Ray Sington, Crowcroft, The Old Granary (no address) (72) Inventor Paul Edward Dunn, Worcestershire W. R. 144 H.F., Malvern, Wells Road 217, Flat 5 (72) Inventor Simon David Haslam Gwent N.P. 53 N.F. (No address)

Claims (11)

[Claims] 1. A liquid crystal material layer disposed between two substrates, a color filter layer formed on at least one of the two substrates, and a liquid crystal material layer disposed between the color filter layer and the liquid crystal material layer. A polarizing layer for compensating depolarization of linearly polarized light in the color filter layer, wherein the polarizing layer is made of an oriented and polymerized molecular film. 2. The liquid crystal device according to claim 1, wherein the molecular coating is aligned by exposure to linearly polarized light. 3. The liquid crystal device according to claim 1, wherein the molecular film includes a carrier medium mixed with dye molecules, which is applied to the at least one substrate. 4. The color filter layer according to claim 1, wherein a flattening layer is provided on the color filter layer, and the film composed of the color filter layer and the flattening layer has a uniform thickness. The liquid crystal device according to claim 1. 5. The liquid crystal device according to claim 4, wherein the refractive index of the flattening layer is substantially equal to the refractive index of the color filter layer. 6. A method for manufacturing a liquid crystal device, comprising: a liquid crystal material layer disposed between two substrates; and a color filter layer formed on at least one of the two substrates. A method for manufacturing a liquid crystal device, comprising: a step of forming a molecular film on a surface of a layer in contact with a liquid crystal material layer; and a step of aligning and polymerizing the molecular film to have a polarizing ability. 7. The method for manufacturing a liquid crystal device according to claim 6, wherein the alignment treatment of the molecular film is performed by exposing with a linearly polarized light. 8. The method according to claim 6, wherein in the step of forming the molecular film, a carrier medium containing a dye molecule is applied to at least one of the substrates. 9. A flat layer having a refractive index substantially equal to the refractive index of the color filter layer is formed on the color filter layer to form a film having a uniform thickness comprising the color filter layer and the flat layer. The method for manufacturing a liquid crystal device according to claim 6, further comprising a step of forming. 10. The method for manufacturing a liquid crystal device according to claim 6, further comprising a step of subjecting the color filter layer to a polishing treatment for flattening the surface. 11. A liquid crystal material layer disposed between two substrates, and a color filter layer formed on at least one of the two substrates, wherein the color filter layer has a polarizing ability. A liquid crystal device comprising: molecules arranged in a color filter layer, wherein depolarization of the linearly polarized light incident on the color filter layer in the color filter layer is compensated for by the polarization ability of the molecule.