JP2003248219A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a reflective liquid crystal device excellent in display characteristics. <P>SOLUTION: The reflective liquid crystal display device comprises a liquid crystal 38 sandwiched between a pair of substrates placed opposite to each other and is provided with coloring regions 36a', 36b', 36c' with respectively different colors and corresponding to a plurality of pixels. The coloring regions have coloring layers formed thereon. The coloring layers are characterized by being provided with thick parts 36a-1', 36b-1', 36c-1' and thin parts 36a-2', 36b-2', 36c-2' with respectively different thickness so as to form a plurality of reflection compartments with respectively different reflectance per pixel region inside thereof. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to a technique for improving visibility by improving a display mode caused by reflected light.

[0002]

2. Description of the Related Art Conventionally, TN (T
Wisted Nematic) type liquid crystal display device, ST
There are various types of devices such as an N (Super Twisted Nematic) type liquid crystal display element and a ferroelectric liquid crystal display element. Among them, there are those that use a polarizing plate to switch the display by utilizing the change in the polarization state of light based on the electric field effect of the liquid crystal, and those that do not use a polarizing plate and the phase change and alignment state of the liquid crystal. In some cases, it is possible to switch between the light transmission state and the light scattering state by the change of the above.

In the latter liquid crystal display device, since no polarizing plate is used, there are advantages that light utilization efficiency is high and bright display can be obtained. The display characteristics in this case are substantially determined by the transparency in the light transmitting state and the scattering intensity or reflectance in the light scattering state.

As an example of a liquid crystal display device which does not use a polarizing plate which has been conventionally used, there is a polymer dispersion type liquid crystal display device shown in FIG. In this device, an electrode 3 made of ITO (Indium Tin Oxide) or the like is formed on the inner surface of the substrate 1, and a metal electrode 4 also serving as a reflective layer made of Al, Cr or the like is formed on the inner surface of the substrate 2. Has been formed. An alignment film 5 made of polyimide, polyvinyl alcohol, or the like is formed on the surfaces of the substrate 1 and the transparent electrode 3, and a similar alignment film 6 is formed on the surfaces of the substrate 2 and the metal electrode 4. A rubbing treatment is applied to these alignment films 5 and 6 in the a direction indicated by the arrow in the figure.

The substrates 1 and 2 are held in a state of facing each other with a predetermined distance (for example, 5 to 10 μm) therebetween by a sealing material, a spacer or the like, and a liquid crystal polymer composite layer 7 is enclosed between both substrates. There is. The liquid crystal polymer composite layer 7 is composed of liquid crystal 7A and particles of polymer 7B dispersed therein.
Both the liquid crystal 7A and the polymer 7B are aligned in the rubbing direction applied to the alignment films 5 and 6.

In the state in which no voltage is applied between the transparent electrode 3 and the metal electrode 4, no electric field is applied, the liquid crystal 7A and the polymer 7B whose alignment directions are aligned are almost the same as shown in FIG. 10 (a). Since it has a refractive index, the liquid crystal polymer composite layer 7 is in a light transmitting state, and the incident light is reflected as it is by the metal electrode 4 which is a reflecting layer. On the other hand, when a predetermined voltage is applied between the transparent electrode 3 and the metal electrode 4, the liquid crystal 7A having dielectric anisotropy is oriented in the electric field direction b as shown in FIG. Liquid crystal 7A and polymer 7 exhibiting directionality
A difference in refractive index occurs between B and B, the liquid crystal polymer composite layer 7 is in a light scattering state, and incident light is scattered.

Various structures and manufacturing methods of the polymer dispersion type liquid crystal display device as described above are disclosed in US Pat.
No. 060 and Japanese Patent Application Laid-Open No. 5-119302.

On the other hand, some liquid crystal display devices have a color filter formed to enable color display. As a liquid crystal display device capable of such color display, there is, for example, one having a sectional structure shown in FIG. This liquid crystal display device is a reflection type, in which a transparent electrode 13 is deposited on the inner surface of a transparent substrate 11 which is one substrate, an alignment film 14 is applied on the transparent electrode 13 and a rubbing treatment is performed in a predetermined direction. A metal electrode 15 made of a metal such as Cr or Al is formed on the inner surface of the transparent substrate 12, which is the other substrate,
A color filter 16 having colored layers (red part) 16a, (blue part) 16b, and (green part) 16c arranged by a predetermined arrangement method is formed on the surface of the metal electrode 15. An alignment film 17 similar to the one described above is deposited on the surface of the color filter 16.

The transparent substrate 11 and the transparent substrate 12 are adhered to each other via a sealing material (not shown) in the same manner as above, and a liquid crystal is enclosed in a region surrounded by the sealing material to form a liquid crystal layer 18. To be done.

In the reflection type liquid crystal display body thus formed, the light incident from the transparent substrate 11 side is reflected by the liquid crystal layer 1.
8. The transparent electrode 13 and the metal electrode 15 are configured to be sequentially transmitted through the color filter 16, reflected by the metal electrode 15, and emitted again from the transparent substrate 11 via the color filter 16 and the liquid crystal layer 18. The orientation of the liquid crystal layer 18 is controlled by applying a predetermined voltage between the liquid crystal layer 15 and the liquid crystal layer 15, and a desired color display can be performed by changing the optical characteristics of the liquid crystal layer 18.

In the reflective liquid crystal display device, in addition to forming the reflective layer made of metal inside the transparent substrate as described above, a reflective layer is formed outside the transparent substrate or the substrate itself. There is a case where is composed of a reflective material.

[0012]

As described above, various types of liquid crystal display devices for displaying images in various formats using liquid crystals have been developed and put into practical use. In this case, the reflective liquid crystal display device does not require a light source such as a backlight and can reduce power consumption, and thus is suitable for use in a portable device or the like. On the other hand, in the case of the reflection type, there is a problem that the display is generally dark and it is difficult to sufficiently enhance the display contrast.

Therefore, in the reflection type liquid crystal display device, it is the most important technical problem to improve the brightness and contrast of display, and various technical problems are solved in order to solve the technical problems. Is being developed. The display element of the type that displays by light scattering as described above is also one of the achievements of the development, and a display element having a bright display and a good contrast can be manufactured.

However, in the case of improving the brightness and contrast of the display in the reflective liquid crystal display device, there is a problem that the light reflected by the metal electrode impairs the visibility of the display. This is because the reflective layer formed by metal electrodes, etc. to improve the brightness and contrast of the display is formed so as to exhibit a high reflectance almost like a mirror. If it is high, the surrounding scenery may be reflected on the display screen, or the direct light emitted from the lighting may enter the eyes of the user and dazzle it.

The visibility of such a reflection type liquid crystal display device is improved to some extent by attaching a non-glare plate or other filters, but these filters may reduce the display brightness or the contrast. Even so, it was not possible to change the basic characteristics of display quality such as the reflection of the background, and it was difficult to significantly improve the visibility.

Further, in the case of the display element utilizing the above-mentioned light scattering, there is an improvement in that the brightness of the display is secured and the contrast is improved by improving the transmittance in the light transmitting state. However, there is a problem that the more the improvement is made, the more the background reflection and the illusion caused by the direct light become more remarkable.

Therefore, the present invention is to solve the above-mentioned problems, and an object thereof is to provide a novel technique for preventing the deterioration of the visibility due to the light reflection of the reflective layer in the reflective liquid crystal display element. is there.

[0018]

Means for Solving the Problems The means taken by the present invention to solve the above-mentioned problems are obtained by sandwiching a liquid crystal layer between a pair of substrates having electrodes on opposite inner surfaces and reflecting on one of the substrates. A layer in which a polymer is dispersed in liquid crystal molecules, a plurality of pixel regions are formed by the electrodes facing each other, and the reflective layer includes a plurality of pixel regions. It is characterized in that a plurality of reflection sections having different reflectances are formed.

According to this means, since a plurality of reflection sections having different reflectances are formed in each pixel area, the light incident from one of the substrates has a different reflectance in each reflection section, and thus is reflected in each pixel area. Since each is modulated, the background is not reflected and the direct light does not enter the eyes even when the liquid crystal layer is in a transparent state, which affects the display formed by the pixel area. The visibility of the liquid crystal display device can be improved without giving

Here, the optical characteristic between the light transmitting state and the light scattering state is controlled by the application state of the voltage applied to the liquid crystal layer. Further, it is preferable that the plurality of reflective sections are formed as back surface side electrodes for applying a potential to the liquid crystal layer.
In this case, since the reflection section is composed of the back surface side electrode, it is not necessary to separately provide the reflection layer, and the reflection section can be formed at the same time in the electrode forming step.

Further, it is preferable that the plurality of reflection sections are made of different kinds of materials or are formed under different conditions. By changing the type or composition of metal or other reflective material or the forming conditions, it is possible to easily form reflective sections having different reflectances.

Further, it is preferable that each of the plurality of reflection sections has a laminated structure in which another reflection film is partially overlapped on the surface of one reflection film. In this case, the reflectance can be changed by partially changing the thickness of the reflective film, or the reflectance can be partially changed by the material exposed on the surface. It can be changed easily. In particular, when the reflective layer is formed as a metal electrode, mutual conduction between the reflective sections can be easily and surely achieved, so that a reflective section having a complicated shape can be easily formed without impairing the function as an electrode. It can be formed and it is also possible to provide multiple reflective sections.

Next, as another means according to the present invention, a liquid crystal is sandwiched between a pair of substrates having electrodes on the inner surfaces facing each other, the one substrate is provided with a reflection layer, and the reflection layer is provided with respect to the reflection layer. A color filter composed of a plurality of color elements formed on the side of the other substrate is arranged, a plurality of pixel regions are formed by the electrodes facing each other, and a liquid crystal is formed by applying a voltage applied to the liquid crystal layer. Control the layers,
The color filter is formed corresponding to the pixel region, and the color filter is selectively formed in a predetermined plane pattern in the pixel region.

According to this means, since the color filter is selectively formed in a predetermined plane pattern in the pixel area, the light incident from one of the substrates is transmitted through the color filter to each pixel. Since the color tone is modulated by the portion where the color filter is formed and the portion where the color filter is not formed in the area, even if the liquid crystal layer is in the transparent state, the background is reflected or the direct light is left as it is. Because it will not get in your eyes in the state,
The visibility of the liquid crystal display device can be improved without affecting the display formed by the pixel region and without sacrificing the display brightness. In addition, since there is a part where the color filter is not formed,
Since the electric field of the electrodes can be directly applied to the liquid crystal without passing through the color filter, it is possible to reduce the driving voltage and increase the driving voltage margin.

Here, the liquid crystal layer has a structure in which polymers are dispersed in liquid crystal molecules, and the light transmission state and the light scattering state are controlled by the voltage application state. Further, the color filter is composed of red, blue and green color elements, or yellow, magenta and cyan color elements. It is preferable that the ratio of the formation area of the color filter in the pixel region is different for at least two of the color elements. According to this means, by making the ratio of the formation area of the color filter different for each color element,
The color tones can be mutually adjusted according to the ratio of the forming area, and the color tone characteristics of the color filter can be adjusted without changing the color tone of the color element itself, so that high-quality color display can be realized.

Further, it is preferable that the plane pattern of the color filter is formed in a single island shape in the pixel region. In this case, since the color filter is formed in a single island shape, it can be dealt with only by making a slight change such as changing the size of the mask pattern. can do.

Further, it is preferable that the plane pattern of the color filter is composed of a plurality of divided pattern portions dispersedly arranged in the pixel region. According to this means, since the color filter including the plurality of division pattern portions is formed in the pixel region, incident light or reflected light can be sufficiently modulated, and the display quality can be surely improved. it can.

Next, as still another means according to the present invention, a liquid crystal is sandwiched between a pair of substrates having electrodes on the inner surfaces facing each other, and a reflective layer is provided on the one substrate, and the reflective layer is provided on the reflective layer. On the other hand, a color filter composed of a plurality of color elements formed on the side of the other substrate is arranged, a plurality of pixel regions are constituted by the electrodes facing each other, and a voltage applied to the liquid crystal layer is applied. The liquid crystal layer is controlled, the color filter is formed corresponding to the pixel region, and the color filter has a light and shade pattern having a predetermined dark region and a light region in the pixel region. It is characterized by

According to this means, since the color filter is provided with the light and shade pattern in the pixel area, the light or reflected light is modulated by the light and shade pattern, so that even if the liquid crystal layer is in the transparent state, the background The liquid crystal display does not affect the display formed by the pixel area and does not impair the brightness of the display, because The visibility of the device can be improved.

Here, the liquid crystal layer has a structure in which a polymer is dispersed in liquid crystal molecules, and the light transmission state and the light scattering state are controlled by the voltage application state. In addition, the color filter is a red, blue, green color element, or yellow,
It consists of magenta and cyan color elements.

In the light and shade pattern, the color filter may have a thin portion and a thick portion having different thicknesses,
Alternatively, it may be formed by partially changing the color tone of the color filter.

Further, it is preferable that the gradation pattern of the color filter in the pixel area is different from each other for at least two of the color elements. According to this means, the average thickness of the color filter can be changed by changing the density difference between the dark and light portions in the light and dark pattern, the ratio of the pattern area, and the like, so that the color tones of the color elements are mutually adjusted. Therefore, high quality color display can be realized.

In each of the above means, for example, the liquid crystal layer is
It can be applied to a polymer-dispersed liquid crystal display device, which is a liquid crystal polymer composite layer in which a liquid crystal and a polymer are compatible with each other and the liquid crystal and the polymer are phase-separated.

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of a liquid crystal display device according to the present invention will be described with reference to the accompanying drawings.

(First Reference Example) FIG. 1 shows a structure of a liquid crystal cell of a liquid crystal display device of a first reference example according to the present invention. Similar to the display device of FIG. 10 described above, the transparent substrates 1, 2
, A transparent electrode 3 and a metal electrode 4, and a liquid crystal polymer composed of a liquid crystal 7A and a polymer 7B aligned between the transparent substrates 1 and 2 in a predetermined direction by alignment films 5 and 6. The composite layer 7 is enclosed.

As in the conventional example, the liquid crystal polymer composite layer 7 becomes transparent and becomes transparent when the liquid crystal molecules 7A and the polymer 7B have almost the same refractive index for incident light and reflected light. The alignment state of the liquid crystal molecules 7A having the dielectric anisotropy changes according to the change of the electric field applied state, which causes a difference in the effective refractive index between the liquid crystal molecules 7A having the refractive index anisotropy and the polymer 7B. When it occurs, it becomes a light scattering state and becomes cloudy. For example, the liquid crystal polymer composite layer 7 can be made cloudy when no electric field is applied and made transparent when an electric field is applied, or made transparent when no electric field is applied and made cloudy when an electric field is applied. The light transmission state and the light scattering state of the liquid crystal polymer composite layer 7 are appropriately realized by adjusting the mutual relation of the refractive index between the liquid crystal molecules and the polymer particles.

The metal electrode 4 is formed by depositing Cr entirely on a predetermined pixel region by vapor deposition or sputtering. The surface reflectance of the metal electrode 4 is adjusted to a range of about 50 to 70% depending on the thickness of the Cr layer, film forming conditions, and the like. On a half region on the surface of the metal electrode 4, a dissimilar metal layer 8 in which Al is deposited to a predetermined thickness by a vapor deposition method or a sputtering method is formed.

In the liquid crystal display device formed as described above, the first reflection in which the incident light is reflected by the metal electrode 4 is in the predetermined pixel region D defined by the transparent electrode 3 and the metal electrode 4. A section A and a second reflection section B in which incident light is reflected by the dissimilar metal layer 8 are formed.

The structure of the reflection layer corresponding to each pixel region D of the liquid crystal display device thus formed is shown in FIG.
As shown in (a) to (c), the first reflection section A and the second reflection section B are arranged vertically or horizontally. As shown in (a), (b) and (c) of FIG. 2, various arrangement methods of the first reflective section A and the second reflective section B are considered in relation to other adjacent pixel regions D, Is determined in such a manner that there is no bias as much as possible over the pixel area.
The three types of arrangement methods shown in FIG. 2 each show a case where each pixel region D is divided into two vertically or horizontally, but for example, two vertically.
The divided pixel areas and the horizontally divided two pixel areas may be arranged alternately or appropriately dispersed.

FIG. 3 conceptually shows the structure of a liquid crystal display device having pixel regions D of different modes. As shown in FIG. 3A, the first reflection section A is arranged at the center of each pixel area D, and the second reflection section B is arranged around the first reflection section A. In addition, as shown in FIG. 3B, each pixel region D is divided into four, and two first reflection sections E and two second reflection sections F are provided. Figure 3 (c)
Is a first reflection section E and a second reflection section F similar to FIG.
6 and 7 are provided in each pixel region D, but the case where the partition arrangements in the adjacent pixel regions D are different from each other is shown.

As described above, by forming a plurality of reflective sections on the reflective layer in each pixel area D, each pixel area is divided into a plurality of sections having different reflectances, and the specularity of the reflective layer is obtained. Therefore, even when the liquid crystal polymer composite layer 7 is in a light transmitting state, it is less likely that the background will be projected and direct light will not enter the eyes, and the visibility will be greatly improved. In addition, in order to improve visibility, a plurality of types of reflective sections are arranged in a mosaic pattern,
When arrayed in a pattern, it is effective to set the array period finely, and in some cases it may be arrayed randomly.

When the first and second reflecting sections are formed using Cr and Al as described above, the first and second reflecting sections are formed.
The reflectance of the reflective section can be set to about 50 to 70%, and the reflectance of the second reflective section can be set to about 90 to 100%.
By sufficiently taking the difference in reflectance between the reflective section and the second reflective section, the above effect can be enhanced. On the other hand, the reflectance of the entire pixel area is 70 to 8 as the average of the two.
Since it can be maintained as high as about 5%, the brightness of the display is hardly sacrificed.

In the above-mentioned reference example, the structure of the polymer dispersion type liquid crystal display device (FIG. 1) was described as an example, but the same thing can be said that the light transmission using other light scattering and coloring properties. Liquid crystal display method for displaying by a state transition between a state and a light scattering state or a colored state, for example, a phase transition type display method utilizing a phase transition between a cholesteric phase and a nematic phase, and a dynamic scattering mode of liquid crystal It is also effective when applied to liquid crystal display elements and devices that perform display by various methods that do not use a polarizing plate, such as the above-described method, a display method by orientation dispersion, or other formats. , For example,
The present invention can be applied to a liquid crystal display device using STN liquid crystal and a liquid crystal display device using TN liquid crystal to improve the display quality. Furthermore, the same effect can be obtained by applying the configuration of the present application to a liquid crystal display device in which the pixel electrodes are controlled by active elements and a simple matrix type liquid crystal display device.

In the above-mentioned reference example, since a plurality of reflection sections having different reflectances are formed by partially forming another metal layer on the surface of the metal electrode 4, conduction between the reflection sections is formed. Can be easily obtained, and the conduction state is stabilized, but without overlapping in this manner, different metal layers are formed adjacent to each other, and both are directly conductively connected at the peripheral portion, or It can also be formed by conducting connection through a wiring layer. It is obvious that the reflective layer itself does not have to serve as the electrode, and may be provided separately from the electrode, for example, it may be provided together with the transparent electrode.

Further, the number and shape of the reflection sections provided in the pixel region are arbitrary, but it is desirable to form more reflection sections in a complicated shape and arrangement in order to improve the visibility. Further, as the material of the reflection layer for forming the reflection section, Ag, Ni, Ta, and
Other metals such as other alloys may be appropriately used to provide the difference in reflectance, or resin materials or other materials other than metals may be used.

As a method of making the reflectances different from each other in the plurality of reflection sections, there is a method of changing the thickness of the reflection layer in addition to the method of changing the material of the reflection layer. For example,
The reflectance can be increased by making one reflective section thicker than the other reflective section. In this case, as described above, the first layer is formed on the entire surface, and only one reflective section is provided with the second layer again. It is also possible to form a reflective layer having reflective sections having different thicknesses by a method of forming layers or a method of forming layers in reverse order.

Further, the substantial reflectance can be mutually changed by mutually changing the surface state (surface roughness etc.) of the reflecting surface in the reflecting section. For example, to increase the substantial reflectance by making one reflective section an optical mirror surface, to roughen the surface of the other reflective section, or to form irregularities on the reflective layer surface to increase scattered light. It is also possible to reduce the substantial reflectance.

(Second Reference Example) Next, a second reference example according to the present invention will be described. In this reference example, as shown in FIG. 4, between a substrate 31 and a substrate 32 made of transparent glass,
A liquid crystal display body in which a liquid crystal layer 38 is enclosed.

On the inner surface of the substrate 31, for example, a plurality of stripe-shaped transparent electrodes 33 made of ITO (indium tin oxide) or the like are formed in parallel. An alignment film 34 made of polyimide resin or the like is applied and formed on the surfaces of the electrodes 33 and the transparent substrate 31. The alignment film 34 is rubbed in a predetermined direction.

On the other hand, on the inner surface of the transparent substrate 32, a metal electrode 35 also serving as a reflection layer is formed by depositing a metal such as Cr or Al by a sputtering method or the like. The metal electrode 35 is formed, for example, in a shape divided for each pixel region, and each is connected to a wiring layer (not shown).

The metal electrode 35 may be connected to the wiring layer via an active element such as a MIM (metal-insulator-metal) element or a TFT (thin film transistor). When the metal electrode 35 is connected to the wiring layer via the MIM element, for example, the wiring layer is Ta, the MIM element is a laminated structure of Ta (metal), tantalum oxide (insulator), and Cr (metal), The metal electrode 35 is made of Cr.

A color filter 36 is formed on the surface of the metal electrode 35. The color filter 36 is
For example, it is formed as follows. First, a photosensitive pigment-dispersed resin is applied by a spin coating method, a roll coating method, a flexographic printing method or the like to form a film having a thickness of about 3000 to 15000Å. Next, pre-baking is performed under conditions of a temperature of 50 to 150 ° C. and a time of 5 to 60 minutes, and a plurality of color elements, for example, red, blue, and green colored regions 36a, 36b, and 36c of the three primary colors are made to correspond to the pixel regions. To form sequentially. The colored layer is exposed to light using a mask having a desired shape, developed, and patterned into a desired shape. Then, the temperature is 75 to 20.
Post bake is performed at 0 ° C for 10 to 20 minutes,
Completely cure each colored layer. A protective film (not shown) is formed on the surface of the color filter.

Each of the color filters (colored areas) 36a, 36b, 36c composed of a plurality of color elements is composed of red, blue, and green color elements, and each is formed in a predetermined plane pattern formed by the above manufacturing method. . That is, in each pixel area, the colored pattern portions 36a-1, 36b-1, 36c-1 remaining after the patterning and the missing portions 36a-2, 36b- where the coloring pattern does not exist.
2, 36c-2 are present.

FIG. 6 shows the color filter 3 in this reference example.
It is a top view which shows the plane pattern of FIG. As shown in this figure, a colored layer is usually formed on the entire surface of the colored region corresponding to each pixel region, but in the present reference example, the colored layer formed in the region corresponding to each pixel region is formed. Is a plurality of rectangular colored pattern portions 36a-1, 36b-1, 36c-.
1 is patterned in a state in which a large number of 1s are dispersedly arranged, and the peripheral portions thereof are absent portions 36a-2, 3 in which colored portions are not formed.
6b-2 and 36c-2.

In this reference example, since the colored layers 36a, 36b and 36c are selectively formed in the above-mentioned plane pattern in each pixel region, the incident light incident from the transparent substrate 31 is directly reflected by the metal electrode 35. And again one substrate 31
When the light is emitted from the device, the incident light and the reflected light are modulated such that a color pattern is formed or refracted by the colored pattern portion formed in each pixel region. As a result, on the display surface of the liquid crystal display, the effect of reducing the reflection of the background and the direct reflection of illumination light can be obtained.

In this reference example, the color elements of the color filter are composed of the three color elements of red, blue and green, but the color elements are composed of the three color elements of yellow, magenta and cyan. It may be configured. When a color filter composed of yellow, magenta, and cyan is used, the color filter has high transmission characteristics, and when used as a reflective liquid crystal display device, bright display is obtained.

Further, it is possible to display a clear color by using a white filter as a color filter composed of these three color elements.

In the present reference example, the MIM element is used, but the same effect can be obtained by applying the above-mentioned structure to the pixel electrode using the TFT element. Further, the same effect can be obtained in a simple matrix type liquid crystal display device.

(Third Reference Example) FIG. 7 is a plan view showing a plane pattern of a color filter in a third reference example of the present invention. This reference example is a liquid crystal display body having a structure similar to the vertical cross-sectional structure shown in FIG. 4, similar to the second reference example, description of similar parts is omitted, and similar parts are designated by the same reference numerals. Attach.

In this reference example, the color filter 3
The colored pattern portion 36a formed in a single island shape inside the colored regions 36a, 36b, 36c of the three colors that form 6
-3, 36b-3, 36c-3 are formed. In addition, around these colored pattern portions, the missing portions 36a-4, 36b-4, 36c-4 similar to those of the second reference example are provided.
Exists.

In this reference example, since each colored pattern portion is formed in a single island shape, the mask pattern in the patterning step does not need to be so fine, and can be formed accurately and easily. Also, the mask pattern can be easily changed by simply reducing the pattern size of each colored region while keeping the pattern shape.

In the second reference example and the third reference example,
The size and shape of the colored pattern in each colored region can be appropriately changed. In this case, the ratio of the occupied area (formed area) of the colored pattern portion to the entire colored region can be appropriately adjusted according to the desired color tone of the colored pattern. Further, as shown in FIG. 7, in order to optimize the color tone obtained on the display screen for each type of color tone of the colored region, that is, for each color tone of red, blue and green in the above case. The area ratio of each can be set. Therefore, the ratio of the occupied area is different for each color tone. By doing this, the color tone of the material itself constituting each colored layer can be adjusted by the material and the pigment concentration,
Alternatively, since it is not necessary to make adjustments depending on the film thickness or the like, adjustment of the color tone becomes easy, and management of the manufacturing process of the color filter and quality control become easy.

Further, since the colored pattern is selectively formed in the colored region rather than the entire area, there is always a lack portion without the coloring layer as described above. Since the electric field can be directly applied to the liquid crystal layer 38 from the underlying metal electrode 35 without passing through the colored layer which is a dielectric, the drive voltage can be reduced and the drive voltage margin can be increased. It is also possible to take.

In this reference example, the switching element (TFT,
It can also be applied to a liquid crystal display device using MIM) or a simple matrix type liquid crystal display device.

(First Embodiment) Next, a first embodiment according to the present invention
An embodiment will be described. As shown in FIG. 5, in the present embodiment, the colored layers are formed over the respective colored regions 36a ', 36b', 36c ', but this colored layer is
Thick portions 36a-1 ', 36b-1', 36c-1 ',
It is characterized in that thin portions 36a-2 ', 36b-2', 36c-2 'are formed. FIG. 8 shows the planar shape of the color filter of this embodiment.

Such a colored layer is formed, for example, by subjecting the colored layer formed over the entire surface to an etching treatment or the like to form an uneven shape on the surface or over the first layer formed over the entire surface. In addition, the second layer is partially formed, the second layer is entirely formed on the selectively formed first layer, and the thick portion and the thin portion are separately formed. It can be formed by various methods such as

In this embodiment, the thickness of the colored layer is partially varied to form a shade pattern in each colored region, and the transmitted light can be modulated in color tone. Similar to the second and third reference examples, it is possible to reduce the reflection of the background and the illusion caused by the illumination and improve the display quality.

In this case, the color tone of the color filter can be easily adjusted without changing the color tone of the material itself constituting the colored layer by adjusting the uneven shape of the colored layer itself or the shapes of the thick and thin portions. Can be changed. Here, adjusting the shape of the colored layer means, for example, the depth of unevenness (the height difference between the bottom surface of the concave portion and the top surface of the convex portion) or the difference in the thickness between the thick portion and the thin portion, and / or the concave portion or It is to adjust the ratio of the formation area of the thin portion and the convex portion or the thick portion. These can be controlled more easily than the method of changing the average thickness of the colored layer itself, and the accuracy can be secured.

Further, in order to optimize the mutual color tone relation of the above three color layers, it is necessary to adjust the average thickness of the color layers, but in this case as well, the average thickness of each color layer is simply adjusted. If the average thickness is changed instead of changing the average thickness by changing the concavo-convex shape or the shape of the thick and thin portions, it is possible to easily adjust the color tone relationship between them. It will be possible.

(Second Embodiment) Next, a second embodiment according to the present invention will be described with reference to FIG. In this embodiment, the same parts as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. The color filter 46 is formed on the surface of the transparent electrode 33, and in each of the colored regions 46a, 46b, 46c of the color filter 46, a colored layer having the same uneven shape as that of the first embodiment is formed on the surface. Has been done.

As shown in this embodiment, the color filter may be formed at any position as long as it is on the surface side of the reflective layer. In this embodiment,
It is possible to mix the color filter 46 with a material having conductivity and form a colored layer on the surface of the electrode 33 to form a colored layer (colored electrode) integrated with the transparent electrode 33. As a result, the manufacturing process and structure can be simplified.

It should be noted that the light modulation by the colored layer may result in that a light and shade pattern is formed inside the portion corresponding to each pixel region of the color filter. It may be configured by separately forming the portion and the light-colored portion.

Further, by appropriately combining the formation of the light and shade pattern of the colored layer and the formation of the selective colored pattern portion as in the second reference example, a color filter capable of obtaining optimum display quality can be constructed. You can also

The pattern shape of the light and shade pattern formed by the structure described in the first and second embodiments and the method of partially changing the color tone is arbitrary. For example, in the reflection layer shown in the first reference example. It may be formed in a plane pattern such as a partition shape, and the second reference example or the third reference example.
The colored pattern portion of the reference example may be adopted as one (that is, either the dark color portion or the light color portion) pattern shape.

In each of the above-described embodiments and reference examples, particularly when the liquid crystal layer is formed as a polymer dispersion type liquid crystal display device in which the polymer and the liquid crystal are phase-separated from each other. The background reflection can be significantly reduced while ensuring the brightness of the screen display. This is because it is not necessary to use a polarizing plate in this type of liquid crystal display, so when the present invention is not applied, when the liquid crystal layer is in a light transmissive state, the reflected light of the reflective layer is visually recognized as it is, and particularly the background. This is because the reflection of light and the reflection of illumination light appear clearly.

In a polymer dispersion type liquid crystal display device, in particular, liquid crystal molecules and polymer monomers that are compatible with each other in a liquid crystal cell are aligned in a predetermined horizontal direction, and the polymer monomer is polymerized and cured. For example, it is preferable that the liquid crystal molecules and the polymer particles are mutually dispersed by photopolymerization and curing. In this case,
For example, when no electric field is applied, the liquid crystal molecule and polymer particles are aligned in the same alignment direction, and the liquid crystal polymer composite layer is in a transparent state, and when an electric field is applied, only the liquid crystal molecules are oriented in the electric field direction, resulting in a cloudy state.

In addition to the above polymer dispersion type liquid crystal display device,
As a liquid crystal display device which does not need to use a polarizing plate, a liquid crystal display method for displaying by a state transition between a light transmission state and a light scattering state or a colored state by utilizing light scattering or coloring property, for example, a cholesteric phase There are various types such as a phase transition type utilizing a phase transition between a nematic phase and a nematic phase, a type utilizing a dynamic scattering mode of liquid crystal, a type utilizing alignment dispersion, and the like. By applying it, a remarkable effect can be obtained.

Also, active elements (MIM, TFT)
The same effect can be obtained in the liquid crystal display device and the simple matrix liquid crystal display device using.

[0079]

As described above, since a plurality of reflective sections having different reflectances are formed in each pixel area, the light incident from one of the substrates is reflected by each pixel due to the difference in the reflectances of the reflective sections. Each is modulated in the area.

Further, even if the liquid crystal layer is in a transparent state, the background is not reflected and direct light does not enter the eyes as it is, so that the display formed by the pixel region is affected. Without increasing the visibility of the liquid crystal display device.

Further, it is possible to control the light transmission state and the light scattering state, and display can be performed in various states.

Further, since the reflection section is composed of the back surface side electrode, it is not necessary to separately provide a reflection layer, and the reflection section can be formed at the same time in the electrode forming step.

By changing the type, composition or forming conditions of the metal or other reflective material, it is possible to easily form the reflective sections having different reflectances.

Further, the reflectance can be changed by partially changing the thickness of the reflection film, or the reflectance can be partially changed by the material exposed on the surface. It can be changed easily. In particular, when the reflective layer is formed as a metal electrode, mutual conduction between the reflective sections can be easily and surely achieved, so that a reflective section having a complicated shape can be easily formed without impairing the function as an electrode. It can be formed and it is also possible to provide multiple reflective sections.

Further, since the color filter is selectively formed in the pixel area in a predetermined plane pattern,
When the light incident from one of the substrates is transmitted through the color filter, it is color-tone-modulated by the portion where the color filter is formed and the portion where the color filter is not formed in each pixel area. Even if is transparent, the background is not reflected and direct light does not enter the eyes as it is, so it does not affect the display formed by the pixel area, and
The visibility of the liquid crystal display device can be improved without sacrificing the display brightness. Further, since there is a portion where the color filter is not formed, the electric field of the electrode can be directly applied to the liquid crystal without passing through the color filter, so that the drive voltage can be reduced and the drive voltage margin can be increased. Is also possible.

Further, the liquid crystal layer has a structure in which a polymer is dispersed in liquid crystal molecules, and the light transmission state and the light scattering state are controlled by controlling the voltage application state. The reflectance can be arbitrarily controlled between them.

Since the color filter is composed of red, blue and green color elements, full color display can be obtained.

Further, since the color filter is composed of color elements of yellow, magenta and cyan, the transmittance is high and a bright display can be obtained as a reflection type display device.

Further, by making the ratio of the forming area of the color filter different for each color element, the color tone can be mutually adjusted by the ratio of the forming area, and the color tone of the color filter can be changed without changing the color tone of the color element itself. Since the characteristics can be adjusted, high quality color display can be realized.

Further, since the color filter is formed in a single island shape, it can be dealt with only by making a slight change such as changing the size of the mask pattern. Therefore, the conventional manufacturing process is hardly changed. can do.

Further, since the color filter having a plurality of division pattern portions is formed in the pixel area, incident light or reflected light can be sufficiently modulated, and the display quality can be surely improved. .

Further, since the color filter has the light and shade pattern in the pixel area, the light or reflected light is modulated by the light and shade pattern, so that the background is reflected even if the liquid crystal layer becomes transparent. Or, since it will not get in the eyes with the direct light as it is,
The visibility of the liquid crystal display device can be improved without affecting the display formed by the pixel region and without impairing the display brightness.

Further, the liquid crystal layer has a structure in which a polymer is dispersed in liquid crystal molecules, and the light transmission state and the light scattering state are controlled by controlling the voltage application state. The reflectance can be arbitrarily controlled between them.

Also, since the color filter is composed of red, blue and green color elements, full color display can be obtained.

Further, since the color filter is composed of color elements of yellow, magenta and cyan, the transmittance is high and a bright display can be obtained as a reflection type display device.

Further, since the average thickness of the color filter can be changed by changing the density difference between the dark and light portions in the light and shade pattern and the ratio of the pattern area, the color tones of the color elements are mutually adjusted. Because you can
High quality color display can be realized.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a structure of a first reference example of a liquid crystal display device according to the present invention.

2A to 2C are schematic explanatory diagrams (a) to (c) showing an example of the array structure of various pixel regions in the first reference example.

3A to 3C are schematic explanatory diagrams (a) to (c) showing an example of an array structure of various pixel regions in the first reference example.

FIG. 4 is a vertical cross-sectional view showing the structure of a second reference example of the liquid crystal display device according to the present invention.

FIG. 5 is a vertical cross-sectional view showing the structure of the first embodiment of the liquid crystal display device according to the present invention.

FIG. 6 is a plan view showing a planar structure of a color filter of a second reference example of the liquid crystal display device according to the present invention.

FIG. 7 is a plan view showing a planar structure of a color filter of a third reference example of the liquid crystal display device according to the present invention.

FIG. 8 is a plan view showing the planar structure of the color filter of the first embodiment of the liquid crystal display device according to the present invention.

FIG. 9 is a vertical cross-sectional view showing the structure of a second embodiment of the liquid crystal display device according to the present invention.

FIG. 10 is a vertical cross-sectional view showing the structure of a conventional polymer-dispersed reflective liquid crystal display device.

FIG. 11 is a vertical cross-sectional view showing the structure of a reflective liquid crystal display device including a conventional color filter.

[Explanation of symbols]

1,2 transparent substrate 3 transparent electrodes 4 metal electrodes 5,6 Alignment film 7 Liquid crystal polymer composite layer 7A liquid crystal 7B polymer A, E first reflection section B, F second reflection section D pixel area 36, 36 ', 46 color filters 36a, 36b, 36c Colored area 36a-1, 36b-1, 36c-1 Colored pattern portion 36a-1 ', 36b-1', 36c-1 'Thick wall portion 36a-2 ', 36b-2', 36c-2 'Thin portion

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shuhei Yamada             Seiko, 3-3-3 Yamato, Suwa City, Nagano Prefecture             -In Epson Corporation (72) Inventor Masayuki Yazaki             Seiko, 3-3-3 Yamato, Suwa City, Nagano Prefecture             -In Epson Corporation (72) Inventor Yutaka Tsuchiya             Seiko, 3-3-3 Yamato, Suwa City, Nagano Prefecture             -In Epson Corporation (72) Inventor Eiji Chino             Seiko, 3-3-3 Yamato, Suwa City, Nagano Prefecture             -In Epson Corporation F term (reference) 2H048 BB07 BB10 BB42                 2H091 FA02Y FA14Y FB02 FD02                       FD23 FD24 GA02 LA16 LA17                       MA10

Claims (4)

[Claims] 1. A liquid crystal is sandwiched between a pair of opposed substrates, and a plurality of colored regions each having a different color are provided, and a colored layer is formed in each of the colored regions. A liquid crystal device comprising a thin portion and a thick portion having different thicknesses. 2. The liquid crystal device according to claim 1, further comprising a reflective layer provided on one of the pair of substrates. 3. The liquid crystal device according to claim 1, further comprising a pair of electrodes on an inner surface of the pair of substrates, the pair of electrodes forming a pixel region, and the colored region being the pixel region. A liquid crystal device characterized by being compatible with. 4. The liquid crystal display device according to claim 1, wherein the plurality of colored layers include red, blue, and green color elements.