JPH1124063A - Reflection type liquid crystal display device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate parallax and to improve contrast and color reproducibility by making each color filter possess function for transmitting ultraviolet rays whose wavelength is specified and making the transmissivity of the ultraviolet rays between mutual color filters within specific times. SOLUTION: An optical modulation layer 2 is a liquid crystal layer presenting a light scattering condition in the case of voltage non-impressing and a transparent condition in the case of voltage impressing condition, and is polymer dispersed liquid crystal layer having three-dimensional mesh-like photosetting resin in consecutive layers formed of liquid crystal. The color filter 3 is patterned on the areas of two or more kinds transmitting visible rays which are different each other on the same plane, and the also the transmissivity of the ultraviolet rays of the specified wavelength range of each patterned filter 3 is <=2.5 times between mutual color filters. Thus, even when one pixel is divided by the color filter of plural colors and color display is performed, the light scattering degree and the dispersion of voltage characteristic of the layer 2 corresponding to each color filter inside one pixel are restrained low; so that better scattering condition can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflection type liquid crystal display device using a light scattering type liquid crystal display element, and is used for watches, portable telephones, portable information terminals and the like.
More specifically, the present invention relates to a reflection type liquid crystal display device capable of performing clear color display with high luminance and capable of driving at a low voltage and at a low current.

[0002]

2. Description of the Related Art A liquid crystal display device has many excellent features, such as thinness and low power consumption, and is therefore frequently used as a display panel of equipment for various uses. In recent years, reflection type liquid crystal display devices that do not use a backlight have been vigorously developed. Among them, a light scattering mode reflection type liquid crystal display using a polymer dispersion type liquid crystal that does not require a polarizing plate and can provide a bright display. The device is getting attention.

As a means for coloring these light scattering mode liquid crystal panels, a color filter is arranged in front of a polymer dispersed liquid crystal layer inside an upper substrate, and a mirror reflection characteristic is provided behind the polymer dispersed liquid crystal layer. JP-A-8-184815 in which a reflective layer is disposed, and JP-A-7-184815 in which a color filter is disposed in front of a polymer dispersed liquid crystal layer and an interference filter and a scattering reflective layer are disposed behind the polymer dispersed liquid crystal layer. -1
No. 52029 is disclosed.

[0004]

However, the conventional technique for colorizing a reflective polymer dispersed liquid crystal display device has the following disadvantages. First, in the case where a pixel electrode having specular reflection characteristics is formed on the lower substrate and a color filter is formed on the upper substrate, irradiation of ultraviolet rays is performed through the color filter. Since the ultraviolet rays do not reach the liquid crystal / polymer precursor sufficiently enclosed in the polymer and the polymer precursor cannot be sufficiently polymerized, the light scattering degree and voltage characteristics (threshold voltage, saturation voltage, etc.) of the liquid crystal
However, there is a problem that practical display quality cannot be obtained.

As a method for solving this problem, the use of a color filter that transmits ultraviolet light has been studied.
A display quality satisfying a practical level could not be obtained. Specifically, in the case of a configuration in which one pixel is divided into three by color filters of three primary colors of RGB, ultraviolet light is irradiated through these color filters to separate a liquid crystal and a polymer to form a light modulating layer. Light scattering properties and voltage characteristics (threshold voltage, saturation voltage, and the like) of the light modulation layer were significantly different depending on the filter, and a color tone and contrast that could withstand practical use were not obtained. Furthermore, the color tone of each pixel greatly changes depending on the viewing direction, causing a problem that the color balance is shifted, and the display quality is very poor.

Further, as another solution, a method has been proposed in which a color filter and a reflection layer having specular reflection properties are formed adjacent to each other on the surface of the lower substrate in contact with the liquid crystal.
In this method, since no color filter is formed on the upper substrate, it is possible to uniformly and sufficiently polymerize the polymer precursor by irradiating ultraviolet rays from the upper substrate side. However, in this method, since the color filter is located behind the polymer-dispersed liquid crystal layer, the backscattering characteristics of the polymer-dispersed liquid crystal layer cause the polymer-dispersed liquid crystal layer in front of the color filter of the incident light. The proportion of light scattered and reflected increases. As a result, there is a fundamental problem that the color purity of the display color is greatly reduced.

Second, as a method for solving the above-mentioned problem, Japanese Patent Application Laid-Open No. Hei 8-184815 discloses a configuration and a manufacturing method of a reflection type liquid crystal display device. In this disclosed example, ultraviolet light is irradiated from the lower substrate side where the color filter is not formed to separate the liquid crystal and the polymer, and then the reflective layer ( (Mirror surface). Accordingly, the ultraviolet light reaches the polymer precursor uniformly and sufficiently, and the polymerization of the polymer precursor is uniformly and sufficiently performed. For this reason, the phase separation state between the liquid crystal and the polymer of each color filter is uniform and good. As a result, the light scattering degree and voltage characteristics (threshold voltage, saturation voltage, etc.) of the polymer dispersed liquid crystal layer corresponding to each color filter are uniform and stable, and color reproduction and contrast are improved. However, this method takes a structure in which the reflective layer (mirror surface) is externally arranged on the lower substrate, and thus causes a serious problem in display quality called "parallax (or double reflection)". "Parallax" is a double reflection phenomenon in which a shadow (virtual image) appears to overlap an original image (real image).
When there is glass between the two, there is a distance proportional to the thickness of the glass (that is, the distance between the real image and the virtual image by the mirror surface), and parallax (double reflection) occurs.

When designing a reflective type color liquid crystal display device, the most important thing to pay attention to is the existence of “parallax”. The presence of “parallax” causes not only the problem of double reflection but also the problem that emitted light passes through a color filter of a color different from that of incident light. When at least glass exists between the color filter and the light modulation layer and the reflection layer, there is a distance proportional to the thickness of the glass (that is, a distance between a real image and a virtual image by a mirror surface). The light reflected and returned does not always pass through the same color filter, and may pass through another color filter depending on the incident angle of the incident light. In this case, light in a wavelength range corresponding to a predetermined color is absorbed by each color filter, so that brightness and color purity are reduced. Therefore, a reflective type color liquid crystal display device having "parallax" is not preferable because not only the visibility of the display is greatly deteriorated due to the double reflection, but also the brightness and the color purity are considerably deteriorated.

Third, there is a problem in a conventional liquid crystal display device using a light scattering mode liquid crystal such as a dynamic scattering mode (DSM), a phase transition mode (PCM), or a polymer dispersion mode as a light scattering mode display element. The points will be described. With respect to the liquid crystal display element in the dynamic scattering mode, it is current driven,
The current consumption is 10 to 100 times that of a general TN mode or STN mode, and there is a problem in the reliability of the dynamic scattering mode itself. Therefore, it has been difficult for the conventional dynamic scattering mode liquid crystal display device to be mounted on a device such as a timepiece or a small portable device in which battery life is particularly important.

With respect to a liquid crystal display element in a phase transition mode,
Thermal turbidity may be used in the scattering state. This heat cloudiness
There has been a problem that deterioration is remarkable due to the influence of external stress, heat cycle, and the like. Therefore, it has been difficult for the conventional phase change mode liquid crystal display device to be mounted on a small portable device such as a timepiece and put to practical use. As for the polymer dispersion mode liquid crystal display device, a liquid crystal display device having a microencapsulated structure in which a low molecular nematic liquid crystal is contained in a polymer microcapsule as disclosed in Japanese Patent Application Laid-Open No. 7-152029. There is a liquid crystal display device with a polymer matrix structure in which a low molecular nematic liquid crystal is contained in a porous polymer matrix, but a polymer dispersed liquid crystal with a structure in which liquid crystal droplets are arranged in these polymers. In a display element, liquid crystal molecules are arranged along a polymer wall surface of a liquid crystal droplet, and liquid crystal molecules near the polymer wall surface are strongly affected by the polymer wall surface. For this reason, even if a voltage is applied, it is difficult to arrange in the direction of the electric field, and the array is arranged at a certain angle. Inconsistencies in rates and some clutter remained inevitable. As a result, there is a problem that a good transparent state cannot be obtained even when a high voltage is applied. In addition, when the cell gap is thickened to increase the scattering property, when the voltage is applied, the light is apt to be scattered with respect to the obliquely incident light. . In a droplet-type polymer-dispersed liquid crystal display device, as one method for lowering the driving voltage, there is a method of reducing the cell gap.
If the thickness is less than μm, the scattering state deteriorates considerably, and the scattering state does not reach a practical level. Therefore, it has been difficult for a droplet-type polymer-dispersed liquid crystal display element to achieve both a sufficient scattering state and a transparent state, and to realize good contrast. Therefore, it has been difficult for the conventional droplet-type polymer-dispersed liquid crystal display element to be mounted on a low-voltage, low-power-consumption type small portable device such as a timepiece and put into practical use.

Fourth, in the case of the reflection type liquid crystal display device, unnecessary reflection of external light on the surface of the liquid crystal panel causes a problem that display contents are difficult to visually recognize, and a problem that the use efficiency of external light is reduced. there were. Further, the external light contains ultraviolet light, and in the case of the above-described conventional light scattering mode liquid crystal display element which is relatively weak to ultraviolet light, there is a problem of deterioration of the light modulation layer due to ultraviolet light.

Fifth, if a two-terminal MSI element (metal-semi-insulating film-metal) is used as an active element, it can be driven by a normal voltage averaging method. In this case, the drive voltage Vop of the MSI element and the effective voltage Vlc applied to the liquid crystal (selection voltage Von and non-selection voltage Voff)
(See FIG. 11), the selection voltage Von has a characteristic of changing from a relatively sharp increase state to a rather gradual increase state from a certain region as a logistic curve. Therefore, the drive voltage Vo of the MSI element
Even if p is considerably increased, the effective voltage Vlc applied to the liquid crystal
Becomes almost saturated at a certain level. Therefore, when the saturation voltage (Vsat) of the liquid crystal is large, there is a problem that the practical drive voltage Vop of the MSI element cannot cope with it.

Sixth, when one pixel is driven by a passive matrix type time-division driving (multiplex driving) in which a display element having a structure divided into three by RGB primary color filters is driven by a voltage averaging method, When the light modulation layer is formed by irradiating ultraviolet rays through these color filters to separate the liquid crystal and the polymer into phases, the voltage characteristics of the light modulation layer corresponding to each color filter (threshold voltage: Vth
And saturation voltage: Vsat) greatly varied, and the operation margin (Von / Voff) was considerably deteriorated. Specifically, the minimum threshold voltage (Vth-min) in the variation range of the voltage characteristics becomes lower than the non-selection voltage (Voff) of the time-division driving, causing crosstalk or the maximum saturation voltage. (Vsat-max) becomes higher than the selection voltage (Von) of the time-division driving, and there is a problem that the liquid crystal molecules are not sufficiently arranged in the direction of the electric field and the contrast and color reproduction are deteriorated.

[0014]

Therefore, a reflection type liquid crystal display device of the present invention has been made in order to solve such a problem, and has a light corresponding to each color filter constituted by dividing one pixel. It is an object of the present invention to provide a reflective liquid crystal display device capable of suppressing variations in light scattering degree and voltage characteristics (threshold voltage, saturation voltage, and the like) of a modulation layer and achieving a favorable scattering state, and a method of manufacturing the same. Things.

Further, a reflection type liquid crystal display device capable of driving at a significantly low voltage, having no parallax (double reflection), and realizing high quality display quality with high contrast and excellent color reproducibility, and its manufacture. It is intended to provide a method. Further, it is possible to improve the visibility of display contents due to the reflection of external light and to prevent the light modulation layer from deteriorating due to ultraviolet rays. It is intended to provide.

Still another object of the present invention is to provide a reflective liquid crystal display device capable of displaying a good color even in a dark place such as at night and a method of manufacturing the same. It is another object of the present invention to provide a low-cost reflective liquid crystal display device that enables use of the same color filter manufacturing method and equipment as in the past, and a method of manufacturing the same. Another object of the present invention is to provide a low-cost reflective liquid crystal display device in which a flattening process and an alignment process for a color filter are unnecessary and the manufacturing process is simplified, and a method for manufacturing the same.

Further, a MIS element as an active element,
It is an object of the present invention to provide a reflective color liquid crystal display device which is bright, has excellent color reproduction, and has good contrast display quality by using an active matrix such as a MIM element or a TFT element. In addition, even when time-division driving (multiplex driving) is performed using a passive matrix (simple matrix), no crosstalk occurs when non-selection (Voff) and bright when selection (Von), and color reproduction is performed. It is an object of the present invention to provide a reflective color liquid crystal display device having excellent display quality and excellent contrast. In order to achieve the above object, the reflection type liquid crystal display device of the present invention includes: a transparent substrate on which a transparent electrode is formed; a counter substrate provided to face the transparent substrate; and the pair of substrates facing each other. The light modulating layer provided between the light modulating layer provided on the transparent substrate and the light modulating layer provided on the surface of the transparent substrate in contact with the light modulating layer. A color filter having a spectral characteristic of transmitting ultraviolet light, and a reflective layer provided on a surface of the counter substrate that is in contact with the light modulation layer, and the light modulation layer changes a light scattering state when no voltage is applied. A liquid crystal layer that exhibits a transparent state when applied, and is a polymer-dispersed liquid crystal layer having a three-dimensional network-like photocurable resin in a continuous layer formed by liquid crystals. The color filters are different on the same plane. Two or more types that transmit visible light The ultraviolet transmittance in the specific wavelength range of each of the patterned color filters as well as being patterned in the region is 2.5 times or less between the color filters.

Further, at least one of the following items is provided. a) The color filter is composed of a combination of red, green, blue and transparent, or a combination of yellow, magenta, cyan and transparent. b) The color filter is composed of a combination of red, green, and blue, or yellow, magenta, and cyan, and at least one color filter includes a transparent portion in a region of the color filter.

C) The structure is such that the ends of the color filters overlap with each other with a predetermined width. d) The color filter has an average particle size of 0.1 when the pigment is dispersed.
It is a color filter using a colored photosensitive resist or a dye having a size of not more than μm as a coloring material. e) The reflective layer is made of aluminum, silver, nickel, chrome,
It is a metal or dielectric multilayer film containing at least one of a metal such as palladium and rhodium, an alloy thereof, and an oxide thereof.

F) The electrode has the function of a reflective layer. g) An active element and a pixel electrode connected to the active element are formed on a lower substrate of the reflective liquid crystal display device, and a reflective layer is formed behind the pixel electrode. h) The active element is MSI (metal-semi-insulating film-metal)
It is. i) An anti-reflection layer and an ultraviolet blocking layer that absorbs or reflects ultraviolet light harmful to the liquid crystal are disposed on the surface of the pair of electrode surfaces closest to the observer.

J) In a reflection type liquid crystal display device having a light modulation layer sandwiched between a pair of substrates having at least one transparent electrode, the light modulation layer exhibits a light scattering state when no voltage is applied, A polymer-dispersed liquid crystal layer that exhibits a transparent state when a voltage is applied. In the polymer-dispersed liquid crystal layer, a liquid crystal material forms a continuous layer, and the continuous layer has a three-dimensional network-like photocurable resin. A color filter is formed on a surface of the upper substrate of the reflective liquid crystal display device that contacts the light modulation layer, and a reflective layer is formed on a surface of the lower substrate of the reflection liquid crystal display device that contacts the light modulation layer; A light source unit is provided for making light incident from an end face between the upper substrate and the reflective layer.

K) A light guide plate made of a transparent member is provided in close contact with the outside of the upper substrate, and a light source unit for allowing light to enter from an end face of the light guide plate is provided. Further, the method of manufacturing a reflective liquid crystal display device according to the present invention,
A color filter manufacturing process in which a color filter having a spectral characteristic that transmits light in a specific wavelength range in the visible light range and ultraviolet light in a specific wavelength range required for curing of the polymer-dispersed liquid crystal is formed on a transparent substrate; A step of forming on a substrate, a step of bonding a transparent substrate and a counter substrate to a certain gap with a sealant, a step of injecting a mixture of liquid crystal and a polymer precursor into the gap, and polymerizing the polymer precursor to form a liquid crystal. And a polymer to phase-separate, to form a light modulation layer, an ultraviolet irradiation step of irradiating ultraviolet light from the transparent substrate side at an ultraviolet irradiation intensity at which a threshold voltage greater than the inflection point of the threshold voltage of the liquid crystal is obtained, Is included.

Further, at least one of the following items is provided. 1) When the color filters are patterned on the same plane into two or more types of regions that transmit different visible lights, the ultraviolet transmittance of a specific wavelength range of each of the patterned color filters is determined by the ultraviolet light irradiated in the ultraviolet irradiation step. The thickness of each color filter was determined to be 2.5 times or less the irradiation intensity.

M) Each color filter is formed in such a structure that the ends of each color filter overlap each other with a predetermined width. n) The color filter is formed using a colored photosensitive resist or a dye having an average particle size of 0.1 μm or less when the pigment is dispersed. o) In the step of separating the mixture of the liquid crystal and the polymer precursor by the irradiation of ultraviolet rays, the mixture is maintained at a temperature exhibiting an isotropic phase.

P) The temperature at which the isotropic phase is exhibited is in a temperature range higher by 1 ° C. to 3 ° C. than the nematic isotropic phase transition temperature (NI point) of the mixture of the liquid crystal and the polymer precursor. did. q) In the ultraviolet irradiation step for polymerizing the polymer precursor, ultraviolet light is applied to the polymer precursor through a filter having light scattering properties.

R) Irradiation of ultraviolet rays to phase-separate the liquid crystal and the polymer to form a light modulation layer, and then, on the electrode surface closest to the observer, an antireflection layer and an ultraviolet ray absorbing or reflecting ultraviolet rays harmful to the liquid crystal. It was decided to arrange a barrier layer. According to the reflective liquid crystal display device having the above configuration, even when one pixel is divided by a plurality of color filters to perform color display, the light scattering degree and the voltage of the light modulation layer corresponding to each color filter in one pixel. Variations in characteristics (such as threshold voltage and saturation voltage) can be kept low, and a good scattering state can be achieved.

Further, driving at a significantly low voltage becomes possible, and the problem of double reflection can be solved. Also, high-quality display quality with high contrast and excellent color reproducibility is realized. In addition, a highly reliable reflective liquid crystal display device can be realized by improving the poor visibility of display contents due to reflection of external light and preventing deterioration of the light modulation layer due to ultraviolet rays.

Further, it is possible to provide a reflection type liquid crystal display device capable of performing a good color display even in a dark place such as at night. Further, the same color filter manufacturing method and equipment as those of the related art can be used, and a low-cost reflective liquid crystal display device can be realized. Further, the flattening process and the alignment process of the color filter are not required, the manufacturing process is simplified, and a low-cost reflective liquid crystal display device can be realized.

Also, a MIS element as an active element,
By using an active matrix such as a MIM element or a TFT element, it is possible to provide a reflective color liquid crystal display device which is bright, has excellent color reproduction, and realizes display quality with good contrast. In addition, even when time-division driving (multiplex driving) is performed using a passive matrix (simple matrix), no crosstalk occurs when non-selection (Voff) and bright when selection (Von), and color reproduction is performed. A reflective color liquid crystal display device which is excellent in display quality and realizes a display quality with good contrast can be provided.

[0030]

Embodiments of the present invention will be described below. In a reflective color liquid crystal display device, "brightness" is the most important factor. At present, a transmissive color liquid crystal display device performs color display by a three primary color filter system in which one pixel is divided into red (R), green (G), and blue (B) using a backlight. . Accordingly, since the color filter for the transmission type color liquid crystal display device has a very high density, if it is applied to the reflection type as it is, the efficiency of use of light is poor and a very dark display is obtained. Therefore, a color filter used in a reflection type color liquid crystal display device must be a color filter that is excellent in transparency, bright, and has high color purity than a color filter for a transmission type color liquid crystal display device.

The use of a color filter that is excellent in light transmittance and high in color purity, even when incident light and reflected light pass through color filters of different colors, is more effective than when a conventional color filter is used. , Light loss is reduced. Also, the brightness is reduced to 1/3 by the color filter.
The fundamental problem that the number decreases to a certain extent can be solved to some extent. Therefore, if the transmittance and color purity of the color filter are improved to increase the average transmittance, light loss is reduced, and a color display that is brighter and has higher color purity can be expected. But,
If the average transmittance of the color filter is increased unnecessarily, a light color tone is obtained, and the ability of color reproducibility is reduced. Therefore, it is very important to optimize the average transmittance of the color filter.

As one countermeasure for ensuring brightness, the present invention does not provide a black matrix in the color filter. Therefore, there is a possibility that light leaks from gaps between the color filters. The light leakage from the gap between the color filters contributes to the brightness of the display, but deteriorates the contrast and the color purity. In order to prevent light leakage from the gap between the color filters, a structure in which the ends of the color filters overlap each other with a predetermined width (see FIG.
) To form each color filter.

Here, the overlapping portion of the end portion of the color filter has a concavo-convex structure in which the thickness of the color filter is increased by one layer as compared with other portions. Since the polymer network type polymer-dispersed liquid crystal layer which does not require the alignment treatment is used, there is no problem of display defects such as alignment defects or alignment disorder of the liquid crystal due to the unevenness of the substrate surface. Therefore, a flattening process for preventing a liquid crystal alignment defect due to a step of each film thickness of an RGB color filter required for a TN mode liquid crystal display element or the like is unnecessary.

As described above, the overlapping structure of the end portions of the color filters prevents light from leaking into the gaps between the color filters without using the black matrix, so that they are bright, have excellent color purity, and have high contrast. An excellent reflective color liquid crystal display device can be realized. Furthermore, since a polymer network type liquid crystal layer of a polymer network type is used for the light modulation layer, flattening processing and alignment processing of the color filters are not required, and display appearance defects such as alignment disorder due to steps between the RGB color filters also occur. As a result, good display quality can be obtained, manufacturing cost and manufacturing time can be reduced, and the yield can be improved at the same time.

Here, when color display is performed by a color filter method, a combination of three primary color filters of yellow, magenta and cyan is displayed in addition to a combination of three primary color filters of red, green and blue as a display unit. It is good also as a unit. Further, a combination of two or more different colors may be configured as a display unit. Further, the color filter may be configured with a combination of four colors of red, green, blue and transparent as a basic unit. In this case, a brighter display is obtained, but color reproduction is slightly reduced. Further, the color filter may be configured such that a combination of three primary colors of red, green, and blue is used as a basic unit, and at least one color filter includes a transparent portion in the same region. In this case, a brighter display can be obtained without increasing the number of divided pixel electrodes. However, color reproduction is slightly reduced.

As a method for manufacturing a color filter, there are manufacturing methods such as a pigment dispersion method, a dyeing method, a printing method, and an electrodeposition method. In the case of the present invention, a pigment dispersion method or a dyeing method is preferably used in order to produce a color filter which is excellent in transparency, bright and has high color purity. The color characteristics and transmission characteristics of the color filter by the pigment dispersion method are determined by the type of the pigment, the fineness of the pigment, the method of dispersing in the photosensitive resin, and the like, and the coating film thickness.
The pigments forming the R, G, and B color layers have spectral transmittance characteristics,
The selection is made in consideration of heat resistance, weather resistance, dispersibility in resin, and stability. There are various types of pigments, such as monoazo type, diazo type, anthraquinone type, phthalocyanine type, etc., each having different characteristics, considering the LCD product function, process aspect, etc. Is common. The selected pigment is initially a crystal or an agglomerate (secondary particle) of a couple of firmly bound particles (primary particles). Therefore, the secondary particles (agglomerates) must be dispersed in the state of primary particles and kept in a stable state. Factors that affect this stable dispersion state include the properties of the primary particles of the pigment, the degree of refining, the bonding strength, the type of binder solvent, additives, and polishing. The average particle size of the finely divided pigment in the finally obtained dispersion state has a great influence on the spectral transmittance. Therefore,
The fineness and dispersion of the pigment greatly affect the transparency and color purity of the color filter, and in order to achieve good transparency and color purity, the average particle size of the pigment when dispersed is 0.09 μm or less. It is necessary.

As a method of manufacturing a color filter having high transparency and excellent color purity, there is another dyeing method using a dye. Using this manufacturing method, the color filter of this embodiment is manufactured. Is also good. In the present invention, a polymer network type polymer dispersed liquid crystal layer (PN-LC
Layer). The PN-LC layer as a light modulating layer irradiates ultraviolet rays to a mixed solution in which a liquid crystal and a polymer precursor are uniformly mixed and dissolved, thereby polymerizing the polymer precursor and phase-separating the liquid crystal and the polymer. Produced by

The characteristics of the PN-LC layer used in the present invention are as follows:
It is greatly affected by ultraviolet irradiation conditions (ultraviolet irradiation intensity, time, temperature, etc.). In particular, the magnitude of the ultraviolet irradiation intensity has a very large effect on the polymer network structure of the PN-LC layer. The pore size distribution and the average pore size of the polymer network directly affect light scattering.

Among the properties of the PN-LC layer, the property directly related to the light scattering property is the turbidity. The cloudiness refers to the transmittance of the light modulation layer in a state where no voltage is applied. Deterioration of the light scattering property means that the turbidity is degraded, in other words, that the transmittance in the state where no voltage is applied is increased. FIG. 9 shows the PN- used in the present invention.
The light scattering property (white turbidity) of the LC layer and the specific wavelength (in this case, 3
5 is a graph showing the relationship with the UV irradiation intensity (65 nm). As is clear from FIG. 9, the turbidity worsens exponentially as the intensity of ultraviolet irradiation decreases. It should be noted that such light scattering (white turbidity) and specific wavelength (in this case, 365 n
m) is related to the UV irradiation intensity as follows: R, G, B, Y, M
The same holds true when the mixture of the liquid crystal / polymer precursor is irradiated with ultraviolet rays through a color filter such as C. That is, when irradiating the mixture of the liquid crystal / polymer precursor with ultraviolet light of a specific wavelength (for example, 365 nm) through color filters of different colors, if the intensity of the ultraviolet light transmitted through the color filters is set to the same magnitude, , The same cloudiness is obtained regardless of the color.

In order to realize a good light scattering property (white turbidity), the pore size of the polymer network (three-dimensional network structure) should be a pore size distribution with little variation at about the wavelength of visible light, that is, a uniform pore size. The average pore diameter of the polymer network (three-dimensional network structure) is preferably in the range of 0.4 μm to 3.5 μm. More preferably, it is in the range of 0.5 μm to 1.8 μm, and when the average pore diameter is in this range, the best light scattering state (white turbidity) can be realized. The average pore diameter of the three-dimensional network structure is 0.4 μm.
If it is out of the range of m to 3.5 μm, the light scattering state (white turbidity) is deteriorated, and the contrast is significantly reduced.

The light scattering state (white turbidity) of the light modulating layer is determined by the light scattering mode of the reflection type liquid crystal color display device.
This is one of the factors that contributes most to the “brightness of the display.” If the light scattering degree of the light modulation layer is sufficient, the luminance is improved and the contrast is good. If it is too high, on the contrary, light reflected by the reflective layer cannot be partially emitted from the surface of the liquid crystal panel, and the reflection efficiency decreases,
The display tends to be dark. The reason for this is that when light reflected by the reflective layer is emitted from a high-refractive-index material such as a light modulation layer and glass to a low-refractive-index material such as air, light that has become larger than the critical angle is This is because the light is returned to the inside of the light modulation layer again by the total reflection and cannot be emitted from the liquid crystal panel. Therefore, if the light scattering degree of the light modulating layer is too high, the result is that the range of attenuation of luminance due to the viewing angle is increased, which is not preferable.

The voltage characteristics of the PN-LC layer (Vth,
Vsat, steepness, etc.) and response speed have a strong correlation with white turbidity (transmittance when no voltage is applied). Response speed (especially, response speed at the time of falling) and steepness (γ = Vs
at / Vth) tends to worsen in proportion to the decrease in turbidity. In addition, when the opacity is low, the contrast ratio tends to deteriorate, and the degree of color shift due to the viewing angle tends to increase.

On the other hand, the saturation voltage (Vsat) and the threshold voltage (Vth) tend to decrease in proportion to the decrease in turbidity. That is, the voltage decreases. Therefore, the light scattering state (white turbidity) of the light modulation layer depends on the display brightness and the voltage characteristics (Vth, Vsat,
Such characteristics greatly affect various characteristics such as steepness, response speed, and contrast ratio. Therefore, the optimum value of the degree of white turbidity must be set in consideration of these various characteristics. In other words, in the ultraviolet irradiation step, the irradiation intensity of the ultraviolet light applied to the liquid crystal / polymer precursor must be set to an optimum value.

Next, the PN- used in the light modulating layer of the present invention.
UV irradiation intensity of LC layer and voltage characteristics of liquid crystal (Vth, Vth
(sat) will be described. FIG. 10 is a graph showing the relationship between the ultraviolet irradiation intensity and the voltage characteristics (Vth, Vsat) of the liquid crystal. As is apparent from this figure, the voltage characteristics (Vth, Vsat) of the liquid crystal increase in proportion to the ultraviolet irradiation intensity. Further, the saturation voltage of the liquid crystal (Vsa
t) and the threshold voltage (Vth) have the point F as an inflection point. That is, when the ultraviolet irradiation intensity is higher than the point F, the saturation voltage (Vsa
t) and the threshold voltage (Vth) monotonically increase with almost the same slope, but when the ultraviolet irradiation intensity is below the point F, the slope of the saturation voltage (Vsat) and the threshold voltage (Vth) becomes the slope above the point F. Greater than. In particular, the slope of the threshold voltage (Vth) is considerably larger than the slope of the saturation voltage (Vsat).

As a result, the sharpness of the liquid crystal (γ = Vs
(at / Vth) changes rapidly from the point F. Specifically, when the ultraviolet irradiation intensity is higher than the point F, the steepness (γ) is good, but when the intensity is smaller than the point F, the steepness (γ) is significantly deteriorated. Therefore, in order to obtain good steepness (γ), the UV irradiation intensity needs to be larger than point F. In order to realize time-division driving (multiplex driving) in a reflection type liquid crystal display device, this good steepness (γ) is a very important required characteristic.

The point F (inflection point) of the ultraviolet irradiation intensity shown in FIG. 10 is also shown in FIG. 9 described above. As is clear from FIG. 9, the point F also corresponds to a region where the white turbidity starts to deteriorate exponentially rapidly. As described above, in order to obtain a good turbidity, it is necessary to set the ultraviolet irradiation intensity to a value larger than the point F. As described above, the turbidity of the liquid crystal, the voltage characteristics (Vth, Vsat), and the steepness (γ = Vsat / Vt)
h), various characteristics such as the response speed (especially the response speed at the time of falling) are as follows.
It changes drastically.

Next, the condition of the RBG color filter for obtaining the characteristics of the liquid crystal corresponding to the time-division driving (multiplex driving) in the reflection type liquid crystal display device of the passive matrix type, and the relationship between the liquid crystal / polymer precursor. The UV irradiation intensity for phase separation will be described. Here, the passive matrix type time-division driving (multiplex driving) method is a voltage averaging method, and Voff described below represents an effective voltage when not selected, and Von represents an effective voltage when selected.

In order to realize a passive matrix type time-division driving (multiplex driving) capable of producing a bright, high-contrast display quality without crosstalk, the threshold voltage of the liquid crystal of the PN-LC layer ( Vth) is higher than the non-selection voltage (Voff) of the time division driving, and PN−
The saturation voltage (Vsat) of the liquid crystal in the LC layer must be lower than the selection voltage (Von) for the time division driving. That is,
Steepness of liquid crystal in PN-LC layer (γ = Vsat / Vth)
Must be smaller than the value of the operation margin (Von / Voff) of the time division driving. Furthermore, the voltage characteristics (Vth, Vth) of the liquid crystal of the light modulation layer corresponding to each color filter
It is necessary to make the variation range of (sat) smaller than the value of the operation margin (Von / Voff) of the time-division driving.

More specifically, the minimum threshold voltage (V) of the voltage characteristics (Vth, Vsat) of each of the RGB color filters is
th-min) is the non-selection voltage (Voff) of the time-division driving.
It must be higher and the maximum saturation voltage (Vsat-max) must be lower than the selection voltage (Von) for time division driving. That is, the sharpness of the liquid crystal of the PN-LC layer (γ = Vsat
−max / Vth−min) must be smaller than the value of the operation margin (Von / Voff) of the time-division driving. Therefore, in order to satisfy these characteristics of the liquid crystal, it is very important that the ultraviolet irradiation intensity for phase-separating the liquid crystal and the polymer has a value larger than the point F (inflection point). It is also very important to keep the variation in the ultraviolet transmittance of each color filter within a predetermined range.

Therefore, according to the present invention, a reflection type color liquid crystal display device compatible with time-division driving (multiplex driving) of a passive matrix type, which does not generate crosstalk, and which can provide a bright, high-contrast display quality, is realized. Therefore, the UV transmittance of each color filter in a specific wavelength range is determined to be within 2.5 times between the color filters. Therefore, each color filter is manufactured by relatively adjusting the film thickness of each color filter, the average particle size of the color material (0.09 μm or less) or the density of the color material.

Further, as a method of manufacturing a liquid crystal display element, the UV irradiation intensity for separating a liquid crystal and a polymer from each other has an UV irradiation intensity at which a threshold voltage higher than the inflection point of the threshold voltage of the liquid crystal is obtained, that is, , The irradiation intensity of the ultraviolet rays at the point F or higher, and the variation of the irradiation intensity of the ultraviolet light between the color filters is specified to be within 2.5 times. Next, as a reflection type color liquid crystal display element of the present invention, an active element M
The UV irradiation intensity in the case of an RGB color filter system using an SI element (metal-semi-insulator-metal) and using a PN-LC layer as a light modulation layer will be described.

FIG. 11 is a graph showing the relationship between the driving voltage Vop of the MSI element and the liquid crystal effective voltage Vlc. MS
When driving the I element, a driving method based on a normal voltage averaging method is used. As is apparent from FIG.
The value of the non-selection voltage Voff related to h is fairly low, and the curve of Voff gradually increases gradually. On the other hand, the selection voltage Von related to Vsat of the liquid crystal changes from a relatively sharp increase state to a gradual increase state with a certain region as a boundary, eventually reaches a peak (maximum value), and thereafter becomes a decreasing curve.

Here, when the UV transmittance of the RGB color filters is significantly different from each other, the UV irradiation intensity of the liquid crystal / polymer precursor mixed solution in the light modulating layer significantly fluctuates. Assuming that the variation range of the ultraviolet irradiation intensity is a variation range from the point F to the point G, from FIG. 10, the threshold voltage (Vth) of the liquid crystal varies in the range from Vth1 to Vth2, and the saturation voltage (Vsat) varies from Vsat1 to Vsat2.
Range.

As shown in FIG. 11, regarding the threshold voltage (Vth) of the liquid crystal, the value of the threshold voltage (Vth) of the liquid crystal when the ultraviolet irradiation intensity fluctuates in the range from the point F to the point G is Vth1.
To Vth2 and the non-selection voltage Voff of the MSI element.
Is much higher than the value of, there is no problem of liquid crystal crosstalk. On the other hand, regarding the saturation voltage (Vsat), the value of the saturation voltage (Vsat) of the liquid crystal when the ultraviolet irradiation intensity fluctuates in the range from the point F to the point G is from Vsat1 to Vsat2. Therefore, in order to sufficiently arrange the liquid crystals in the direction of the electric field, a minimum liquid crystal effective voltage Vlc of Vsat1 to Vsat2 is required.

However, as is clear from FIG.
The curve of the selection voltage Von has a peak value (maximum value). And the peak value (maximum value) of this selection voltage Von
Represents the variation range of the saturation voltage of the liquid crystal (Vsat1 to Vsat).
Only part of 2) can be satisfied. Than this,
In order for the liquid crystal to be sufficiently aligned in the direction of the electric field, the Vs
It is necessary at least that the variation range of at be equal to or less than the peak value (maximum value) of the selection voltage Von of the MSI element. In other words, it is necessary to limit the variation range of the ultraviolet irradiation intensity within a predetermined range. That is, RG
This means that it is necessary to limit the ultraviolet transmittance of the B3 primary color filters to within a predetermined range between the color filters.

In the present invention, in order to solve the above-mentioned problems, the range of the set value of the UV irradiation intensity for irradiating the mixed solution of the liquid crystal / polymer precursor of the light modulation layer in the UV irradiation step is as shown in FIG.
The UV irradiation intensity at point F of 0 is the lower limit, and the UV irradiation intensity at point F is 2.5 times or 50 m.
The range of the UV irradiation intensity was set with the smaller value as the upper limit among the values to which W was added.

Further, the RGB color filters are manufactured so that the UV transmittance in a specific wavelength range is 2.5 times or less between the color filters. More preferably,
Point L, which is a value obtained by adding α [mW / cm ² ] to the ultraviolet irradiation intensity at point F in FIG. Is the range (L point to M point) of the ultraviolet irradiation intensity with the smaller value as the upper limit (hereinafter, referred to as point M) among the values obtained by adding.

The reason that the point L (point F + α) is set as the lower limit of the ultraviolet irradiation intensity is that the point F is an inflection point, and the voltage characteristics of the liquid crystal (Vth, Vsa
Since t) changes abruptly and is unstable, point L is set as the lower limit of the ultraviolet irradiation intensity as an ultraviolet irradiation region where more stable voltage characteristics and opacity can be obtained. 10 and FIG.
1, the Vsat at the point L (lower limit) of the ultraviolet irradiation intensity
Is represented as Vsat-L, and Vsat at the ultraviolet irradiation intensity at the point M (upper limit) is represented as Vsat-M.

As described above, when one pixel is constituted by being divided by a plurality of color filters of different colors, the ultraviolet transmittance of a specific wavelength (in this case, 365 nm) of each color filter is set between the color filters. It was determined to be within 2.5 times. Therefore, each color filter is manufactured by relatively adjusting the film thickness of each color filter, the average particle size of the color material (0.09 μm or less) or the density of the color material.

Further, as a method of manufacturing a liquid crystal display element, the UV irradiation intensity for separating a liquid crystal and a polymer from each other is determined by the UV irradiation intensity at which a threshold voltage higher than the inflection point of the threshold voltage of the liquid crystal is obtained, that is, F The UV irradiation intensity was not less than the point, and the variation of the UV irradiation intensity between the color filters was specified to be within 2.5 times. Therefore, under these manufacturing conditions, the ultraviolet irradiation intensity is in a predetermined optimized range (FIG. 10).
And the light modulation layer corresponding to each color filter, such as white turbidity, voltage characteristics (threshold voltage, saturation voltage, steepness, etc.), and response speed. It has become possible to realize good values with optimized characteristic values.

The light-scattering mode reflection type color liquid crystal display device having the above-mentioned structure, for example, a light-scattering mode reflection type color liquid crystal display device corresponding to a passive matrix type time division drive (multiplex drive), and A light-scattering mode reflective color liquid crystal display device using an MSI element as an active element, etc., was able to realize a high-brightness color tone, color balance, and good contrast that can be used practically.

[0062]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below using embodiments. (Embodiment 1) FIG. 1 is a sectional view showing the structure of a reflective type color liquid crystal display device of this embodiment. In this embodiment, a substrate on which an MSI element (metal-semi-insulator-metal) is formed as an active element array is used as a lower substrate.

As shown in FIG. 1, the liquid crystal display element 1 has a column electrode 13 extending in the column direction provided by a transparent electrode, an upper substrate 11A, and a pixel electrode 17 made of a transparent conductive film such as ITO. The lower substrate 11B provided with the MSI element 19 on the portion is provided. The MSI element 19 includes a second electrode 14 made of an opaque conductive film provided on a pixel electrode, a semi-insulating film 15, and a row electrode 16. The row electrode 16 is formed on the semi-insulating film 15 and extends in the row direction. Further, the light modulating layer 2 is sandwiched between the upper substrate 11A and the lower substrate 11B, and the three primary color filters 3 of red, green, and blue are formed on the upper substrate in contact with the light modulating layer. The reflective layer 4 and the insulating layer 5 are formed between the pixel electrode and the pixel electrode. The two substrates are held so that the cell gap is 10 μm.

The semi-insulating film 15 is formed of SiOx, SiNx, or the like, contains a Si component in a larger amount than the stoichiometric composition, has a resistivity of 10 ⁸ to 10 ¹³ Ω-cm, and has a resistance as the electric field increases. Decrease. In this embodiment, the row electrode 16 and the second electrode 1
4 opaque conductive films are provided. The second electrode 14 and the row electrode 16 are made of a metal having a high melting point such as chromium (Cr), molybdenum (Mo), tantalum (Ta), and tungsten (W), a silicide thereof, and aluminum (Al).
A multilayer film of a metal such as gold (Au) or nickel (Ni) and a high melting point metal is preferable.

In this embodiment, a smooth and transparent glass plate is used for the substrates 11A and 11B. In addition, a transparent polymer film may be used in addition to the smooth and transparent glass plate. In this embodiment, the column electrode 13 and the pixel electrode 17 of the transparent conductive film are used.
In2 formed by sputtering or vacuum evaporation
A transparent conductive film made of an O3-SnO2 film (ITO film) patterned by photolithography was used. Although the resistance value of the ITO can be freely adjusted as needed, in this embodiment, the sheet resistance of both the column electrode 13 and the pixel electrode 17 is set to 10Ω / □. As the reflection layer 4, an aluminum thin film was formed while adjusting the film thickness by a sputtering device so as to have specular reflection characteristics. In this embodiment, a film having a thickness of about 2000 Å was formed by a sputtering apparatus. In the present embodiment, since a conductive metal thin film (aluminum thin film) is used as the reflection layer 4, the insulating layer 5 is required between the transparent electrode 12B and the reflection layer 4. In order not to attenuate the spectral reflectance of the reflective layer 4, the insulating layer 5 has a spectral transmittance of more than 90% and a material having high transparency in the visible light region (for example, V.2 manufactured by Nippon Steel Chemical Co., Ltd.).
59-PA) was used. The film thickness of the insulating film 6 was formed by a spinner of about 2 μm so as not to be affected by the metal thin film of the reflective layer 4 when a voltage was applied to the display device. Here, the reflection layer 4 is not limited to aluminum, and can be widely used as long as the material has specular reflection characteristics by sputtering or vapor deposition. In addition to aluminum, a metal such as silver or nickel, an alloy thereof, or an oxide thereof may be used.

The reflection layer 4 may be formed by a dielectric multilayer thin film. Si, SiO2, G as dielectric
e, Y2O3, Al2O3, MgF2, Na3AlF
6, TiO2, ZrO2, Ta2O5, ZnS, ZnS
The material, film thickness, and number of layers of the film of e, ZnTe, etc. are set according to the required reflectance and transmittance. Further, the reflective layer 4 may be formed by a combination of a metal thin film and a dielectric multilayer thin film. When the reflection layer 4 is formed only of the metal thin film, the absorption of the reflection layer is very small. This absorption can be reduced by using a dielectric multilayer thin film in combination.

When the reflection layer 4 is a dielectric multilayer thin film,
Since the dielectric multilayer thin film itself is an insulating material, the insulating layer 5 in FIG. 1 becomes unnecessary. Therefore, it is possible to dispose electrodes directly on the reflective layer 5. In the present embodiment, a polymer network type polymer dispersed liquid crystal layer was used as the light modulation layer 2. The polymer-dispersed liquid crystal layer is formed by uniformly mixing and dissolving a polymer resin such as an acrylate monomer that undergoes a cross-linking reaction and polymerization with ultraviolet light (UV), a nematic liquid crystal having positive dielectric anisotropy, and an ultraviolet curing initiator. The solution,
It is manufactured by injecting into an empty liquid crystal panel, curing only the polymer resin by UV exposure, and phase-separating nematic liquid crystal having positive dielectric anisotropy. At this time, when the ratio of the blending amount of the polymer resin and the nematic liquid crystal is large, the ratio of the polymer resin is large, and independent liquid crystal droplets (liquid crystal droplets) are formed. On the other hand, when the proportion of the polymer resin is small, the polymer resin forms a network-like (network-like) structure, and the liquid crystal is included in the network structure (three-dimensional network-like structure) of the polymer resin. It exists as a continuous phase.

In the embodiments of the present invention, the polymer-dispersed liquid crystal layer used as the light modulating layer is formed by microencapsulating nematic liquid crystal having positive dielectric anisotropy or by forming liquid crystal droplets ( Liquid crystal droplet is not dispersed, but a liquid crystal forms a continuous layer, and a polymer network type polymer dispersed liquid crystal layer having a structure having a three-dimensional network photocurable resin in the continuous layer. It is. For the polymer network type polymer dispersed liquid crystal layer, the ratio of the liquid crystal to the photocurable resin is 60%.
The range of ~ 99% is good. Preferably, the range is 75% to 95%. Further, in order to realize a good light scattering state, the pore size of the polymer network (three-dimensional network structure) has a pore size distribution with little variation at about the wavelength of visible light, that is, a uniform pore size. The average pore diameter of the polymer network (three-dimensional network structure) is preferably 0.4 μm to 2.5 μm. More preferably, the average pore size of the polymer network (three-dimensional network structure) is preferably in the range of 0.4 μm to 1.8 μm. The most favorable light scattering state (white turbidity) can be realized when the average pore diameter is in this range. In addition, polymer network (three-dimensional network structure)
When the average pore diameter of the sample is out of the range of 0.4 μm to 3.5 μm, the light scattering state is deteriorated and the contrast is significantly reduced.

A structure in which a liquid crystal forms a continuous phase by a polymer network (three-dimensional network structure) achieves lower voltage and lower hysteresis than an independent liquid crystal droplet (liquid crystal droplet) structure. Easy to do. Therefore, the ratio of the liquid crystal to the photocurable resin is more preferably in the range of 75 to 99%. As a result, the light scattering characteristics are much better than those of micro-encapsulated nematic liquid crystals or light modulation layers in which liquid crystal droplets are dispersed in a resin matrix. A light modulation layer of a scattering mode having characteristics can be realized.

In this embodiment, "PNM-156" manufactured by Roddick Co., Ltd. was used as a mixed solution of a polymer network type liquid crystal / polymer precursor. The red, green, and blue primary color filters 3 were produced by patterning each color of red, green, and blue by photolithography using a pigment dispersion method in a one-to-one correspondence with the electrodes of each pixel. In a color filter by a pigment dispersion method, a so-called colored photosensitive resist in which a pigment dye and a photosensitive resin are dispersed and mixed in advance is formed into a desired pixel pattern by a photolithography process. Normally, after forming a light-shielding film pattern with a metal film such as chrome, the photolithography process for forming the three primary color filters of red, green, and blue is repeated three times. By carrying out, the color filter is completed. However, in this embodiment, in order to improve the brightness, a black matrix that blocks light is not provided.

The fineness and dispersion of the pigment greatly affect the transparency and color purity of the color filter. Therefore, in order to realize a color filter having good transparency and color purity, the colored photosensitive resist was adjusted so that the average particle size when the pigment was dispersed was 0.1 μm or less. As a method of manufacturing a color filter having high transparency and excellent color purity,
The color filter of this embodiment may be manufactured using a dyeing method using a dye.

Factors that determine the color tone such as the average transmittance (brightness) and saturation of the color filter are the dispersibility and the film thickness of the pigment. In the pigment dispersion method, once the pigment is determined, the color tone (average transmittance [brightness], saturation, etc.) is almost determined by the coating thickness of the colored photosensitive resist. That is, if the thickness of the color filter is reduced, the average transmittance (brightness) of the color filter can be increased, light loss is reduced, and display brightness can be improved. However, on the other hand, the ability of color reproducibility is reduced. Therefore, it is very important to optimize the thickness of the color filter, in other words, the average transmittance (brightness).

In this embodiment, three kinds of colored photosensitive resists of red, green and blue are used as CR7001-12CP, CG7001-12CP,
B7001-12CP was used. Color balance by three primary color filters of red, green and blue, brightness of display,
The film thickness of each color filter was set as shown in Table 1 after comprehensively examining the color purity and the like. That is, the film thickness is set such that red = about 3400 °, green = about 4100 °, and blue = about 2200 °, and the three primary color filters 3 of red, green, and blue are pigmented on the surface of the upper substrate 11A in contact with the light modulation layer. It was formed by a dispersion method. The color filter 3 was manufactured in the order of green, red, and blue. The transmittance of each color filter 3 having these film thicknesses at a specific wavelength (365 nm) is 48% for red and 2 for green.
0%, blue = about 32%. The end portions of the color filters 3 of the three primary colors of red, green, and blue are configured to overlap each other with a predetermined width (about 4 μm in this embodiment) in order to prevent light leakage. An example of this overlapping filter structure is shown in FIGS.

The empty liquid crystal display device thus manufactured,
That is, an empty liquid crystal in which an upper substrate 11A in which red, green, and blue primary color filters 3 are formed on the inner surface and a lower substrate 11B in which a reflective layer 4 of the silver mirror is formed on the inner surface are opposed to each other with a fixed gap. The liquid crystal / polymer precursor mixed solution of the polymer network type “PNM-1” manufactured by Roddick was used for the display element.
56 "(phase transition temperature: NI point = 24.1 ° C.) was vacuum-injected while maintaining the temperature of 30 ° C. to maintain the isotropic state. While maintaining this at a temperature of 25.5 ° C., which is 1.4 ° C. higher than the NI point, 200 mW / c with a metal halide lamp.
m ² ultraviolet rays (365 nm) are irradiated through the color filter 3 for 60 seconds to phase-separate the liquid crystal and the polymer to form the light modulating layer 2, thereby producing a polymer network type polymer dispersed liquid crystal display element 1. did. At this time, a filter that absorbs ultraviolet light having a wavelength of 350 nm or less is used.

Incidentally, the polymer network structure of the light modulation layer 2 (average pore size and pore size distribution of the polymer network, etc.) greatly affects the intensity of ultraviolet irradiation. Therefore, the average pore size of the polymer network is about 1 μm.
In order to form a very sharp hole diameter distribution around m, it is important to use an ultraviolet irradiation method that can start irradiation instantaneously at a predetermined ultraviolet intensity (200 mW / cm ² in this embodiment) using a shutter. Further, the temperature during vacuum injection and the temperature during ultraviolet irradiation need to be higher than the phase transition temperature of the liquid crystal material (NI point = 24.1 ° C. in this embodiment). In particular, it is very important to set the temperature at the time of ultraviolet irradiation for polymerizing the polymer precursor in a temperature range of 1 ° C. to 3 ° C. higher than the phase transition temperature. In this embodiment,
The temperature was set 1.5 ° C. higher than the phase transition temperature.

Further, like the liquid crystal display element 1 of this embodiment,
When a reflection layer of a silver mirror having a specular reflection property is formed on the inner surface of the liquid crystal display element, when the ultraviolet ray irradiated from the ultraviolet lamp is directly irradiated on the liquid crystal / polymer precursor mixed liquid layer, the white turbidity unevenness defect occurs. Easy to occur. This is because
If the ultraviolet light emitted from the ultraviolet lamp is used as it is, since the luminous flux of the ultraviolet light is relatively uniform, interference occurs during repeated reflection between the silver mirror and the glass substrate, and the region where the ultraviolet light is weakened and the region where the ultraviolet light is strengthened are generated. It is presumed that white turbidity unevenness occurs.

As a measure for preventing the occurrence of the white turbidity unevenness, a filter having an ultraviolet scattering property is disposed between the ultraviolet lamp and the liquid crystal display element. Through, as diffused UV light without a uniform luminous flux
The mixture layer of the liquid crystal / polymer precursor is irradiated. By using this measure, uneven white turbidity is greatly reduced, uniform opacity can be obtained over the entire surface of the liquid crystal display element 1, and display quality is greatly improved.

The light modulation layer 2 corresponding to the red, green and blue color filters 3 of the polymer network type polymer dispersion type color liquid crystal display device 1 thus manufactured was observed using a scanning electron microscope. A three-dimensional network structure (polymer network structure) composed of a polymer was confirmed. The three-dimensional network has an average pore size of about 1.
It was around 0 μm. The electro-optical characteristics of the light modulation layer 2 corresponding to the red, green, and blue color filters 3 were measured using a Canon photometer. Table 1 shows the measurement results.

[0079]

[Table 1]

Here, the degree of white turbidity is the transmittance T (0 V) when no voltage is applied. Further, the saturation voltage (Vsat) is an applied voltage that indicates 90% transmittance when the transmittance is 100% when the transmittance is saturated as the applied voltage increases. The threshold voltage (Vth) is an applied voltage indicating a transmittance of 10%. VH50 is a hysteresis characteristic when the transmittance is 50%. VH50 is defined by the following equation.

VH50 = VUP50-VDW50 VUP50 is an applied voltage indicating 50% transmittance when the applied voltage is increased, and VDW50 is an applied voltage indicating 50% transmittance when the applied voltage is decreased. Voltage. From the above measurement results, it was found that the polymer network type polymer-dispersed color liquid crystal display element 1 produced in this example had red, green,
The light modulating layers 2 corresponding to the blue color filters 3 have good light scattering characteristics, and achieve a significant reduction in voltage.
Furthermore, it was confirmed that the light modulation layer was a scattering mode light modulation layer having low hysteresis characteristics.

Further, since a color filter and a reflective layer are formed on the inner surface of the color liquid crystal display element 1, no parallax (double reflection) is generated, and accordingly, a decrease in brightness or color purity due to parallax is caused. There is no problem such as worsening. Therefore, it was confirmed that a bright, clear display with good visibility was obtained, and that the color display quality was good with good contrast, vivid color reproduction and good color balance. The reflective color liquid crystal display device displays a color by a color filter when no voltage is applied, and displays black when a voltage is applied. The contrast is
1: 6. The color purity is (x, y) = (0.47, 0.
33), green (x, y) = (0.30, 0.47), and blue (x, y) = (0.21, 0.23).

Next, a reflective color liquid crystal display device using the three primary color filters 3 of yellow (Y), magenta (M), and cyan (C) was manufactured in the same manner as described above. The three types of colored photosensitive resists of yellow (Y), magenta (M), and cyan (C) are CY7001-12CP, CM7001-12CP, and CM7001-12CP manufactured by Fuji Film Ohlin Co., Ltd.
C7001-12CP was used. The thickness of each color filter 3 is as follows: yellow = about 3900 °, magenta = about 34
00 ° and cyan = about 2800 °.

The light modulating layers 2 corresponding to the YMC color filters 3 of the liquid crystal display element 1 have a good light scattering characteristic, a large voltage reduction, and a scattering mode having a low hysteresis characteristic. It was confirmed that the layer was a light modulation layer. Further, since the color filter and the reflection layer are formed on the inner surface of the liquid crystal display element 1, no parallax (double reflection) is generated, and accordingly, there is a problem that the parallax lowers brightness and deteriorates color purity. Does not occur at all. Therefore, it was confirmed that a bright, clear display with good visibility was obtained, and that the color display quality was good with good contrast, vivid color reproduction and good color balance.

It should be noted that the reflective color liquid crystal display device using the YMC three primary color filters can realize a brighter display as a whole than the reflective color liquid crystal display device using the RGB three primary color filters. However, the color purity tended to be slightly inferior. Therefore, depending on the application, a reflective color liquid crystal display device with a YMC three primary color filter may be more suitable than a reflective color liquid crystal display device with an RGB three primary color filter. (Embodiment 2) FIG. 2 is a sectional view showing the structure of a reflection type color liquid crystal display device of this embodiment. In this embodiment, an antireflection layer and an ultraviolet blocking layer are disposed outside the upper substrate.

As shown in FIG. 2, the liquid crystal display element 1 has an upper substrate 11A provided with a column electrode extending in the column direction by a transparent electrode, a pixel electrode 17 made of a transparent conductive film such as ITO, and the like. And a lower substrate on which the MSI element 19 is provided. The MSI element 19 includes a second electrode 14 made of an opaque conductive film and a semi-insulating film 15 on a pixel electrode.
And the row electrodes 16. The row electrode 16 is
It is formed on the semi-insulating film 15 and extends in the row direction.

Further, the light modulating layer 2 is sandwiched between the upper substrate 11A and the lower substrate 11B, and the three primary color filters 3 of red, green and blue are formed on the surface of the upper substrate 11A in contact with the light modulating layer. The reflection layer 4 is provided between the lower substrate 11B and the transparent electrode 12B.
And an insulating layer 5. The liquid crystal display element 1
Was manufactured in the same configuration as in Example 1, and the cell gap was 10
μm. Further, an antireflection layer 61 and an ultraviolet blocking layer 62 are disposed on the upper surface of the liquid crystal panel closest to the observer.

Since a reflection type liquid crystal display device in the light scattering mode does not require a polarizing plate, it is necessary to protect the liquid crystal layer which is vulnerable to ultraviolet rays by some method. Further, unnecessary reflection of external light on the surface of the liquid crystal panel causes a problem that display contents are difficult to visually recognize, and a problem that the use efficiency of external light is reduced. In order to solve these problems, in the reflection type liquid crystal display device of Example 2, the antireflection layer 61 and the ultraviolet blocking layer 62 are arranged on the upper surface of the liquid crystal panel closest to the observer. In addition to the method of separately arranging the two types of films of the ultraviolet shielding layer and the antireflection layer on the liquid crystal panel, there is a method of arranging the integrated film of the ultraviolet shielding layer and the antireflection layer on the liquid crystal panel. . The latter is more preferable than the former because it has a greater effect in practical use.

The antireflection film is made of SiO2, TiO2, ZrO2, Mg
A single-layer or multi-layer interference film made of an inorganic material such as F2, Al2O3, CeF3, or an organic material such as polyimide, or a film having fine irregularities on the surface (the surface on which light is incident); Any film may be used as long as it prevents regular reflection by scattering. Alternatively, a composite of both may be used.

The ultraviolet blocking layer is a transparent glass plate or a transparent plastic sheet formed so as to absorb or reflect ultraviolet light having a short wavelength of 400 nm or less.
In the second embodiment, the TAC containing about 0.1% of a benzotriazole-based UV absorber is used as the UV blocking layer 45.
(Triacetylcellulose) was used to form an antireflection layer 61 on the upper surface of the TAC using a vacuum evaporator. The antireflection layer 461 uses MgF2 (n = 1.38) for the low refractive index film, and TiO2 (n = 2.3) for the high refractive index film,
CeF3 (n = 1.63) was used as the medium refractive index film, and a total of four layers were laminated. Note that a transparent adhesive layer was disposed on the lower surface of TAC (triacetyl cellulose).

The integrated UV-blocking layer and anti-reflection layer thus formed were adhered to the surface of the transparent substrate 11A of the liquid crystal panel 10, and the reflection spectrum was measured.
The measurement result was as shown in FIG. FIG.
(B) in the case where there is no film in which the ultraviolet blocking layer and the antireflection layer are integrated. As is apparent from FIG.
The reflectance is significantly reduced over the range of nm to 700 nm.

For this reason, the reflection type liquid crystal display device provided with the ultraviolet ray blocking layer and the antireflection layer of Example 2 is more effective than the reflection type liquid crystal display device without the ultraviolet ray blocking layer and the antireflection layer.
Poor visibility of display contents due to reflection of external light on the surface of the liquid crystal panel has been greatly improved, and a reflection type color display device with extremely high visibility can be provided. Further, the deterioration of the liquid crystal due to the ultraviolet rays in the light resistance test is remarkably improved, and a highly reliable reflective color liquid crystal display device can be provided.

(Embodiment 3) An embodiment of a reflection type color liquid crystal display device in which one pixel is constituted by four color filters 3 of red, green, blue and transparent is described below. One pixel is red, green,
It was manufactured in the same configuration as that of the first embodiment except that it was composed of four color filters 3 of blue and transparent colors.
0 μm. In the step of irradiating the mixed solution layer of the liquid crystal / polymer precursor with ultraviolet light, there is a large difference between the ultraviolet transmittances of these four colors (red, green, blue, and transparent). A filter having an ultraviolet transmittance corresponding to the average transmittance of the three color filters 3 of green and blue is used as a mask for irradiating an ultraviolet ray in a transparent region. Thereby, the white turbidity of the light modulation layer corresponding to each color filter 3,
Variations in various characteristics such as voltage characteristics (threshold voltage, saturation voltage, etc.) and response speed can be suppressed, and stable display quality can be realized.

FIG. 7 is a configuration diagram (a four-color configuration of red, green, blue, and transparent) of the color filter 3 of this embodiment. As shown in FIG. 7, one pixel 30 is divided into four color filters of red R1, green G1, blue B1 and transparent W1 (four color regions). Therefore, R1, G1, B
1, W1 displays each color by respective voltage application control. Then, one pixel 30 of the liquid crystal display element includes these four pixels.
By combining color voltage application control, conventional RGB
Halftone color display can be performed more effectively than in the case of a three-color filter. In addition, R1, G
The three color filters 1, 1 are formed on the upper substrate such that their areas (planar areas) are substantially equal and the area ratio is 1: 1: 1. For example, R1, G
Each of the color filters 1 and B1 is 100 μm × 3
It is formed in a rectangular shape of 50 μm. On the other hand, the W1 (transparent) color filter is determined in consideration of the improvement of the degree of brightness by providing the W1 (transparent), and on the other hand, the reduction of the color purity and the visibility by human eyes. . It is preferable to set the area smaller than the other three colors (R1, G1, B1). In this embodiment, 50 μm × 20
It was molded into a 0 μm rectangle. That is, W1 (transparent) has a half area of the other three colors (R1, G1, B1).

The red, green, blue and transparent 4 made in this embodiment
The reflective color liquid crystal display device equipped with the color filter 3 having a color configuration can display brighter than in the first embodiment. Although the color purity was slightly lowered, color reproduction that could be sufficiently used for practical purposes was possible. Here, the color filter 3 may be configured such that at least one color filter includes a transparent portion in the same region using a combination of three primary colors of red, green and blue as a basic unit (see FIG. 8). As shown in FIG.
One pixel 30 is divided by three color filters of red R1, green G1, and blue B1 (three color regions), and a transparent portion is formed in a part of the red R1, green G1, and blue B1 color filters. Is provided, a brighter display can be obtained without increasing the number of divided pixel electrodes. Although the color purity was slightly lowered, color reproduction that could be sufficiently used for practical purposes was possible.

(Embodiment 4) An embodiment of a reflection type color liquid crystal display device provided with a light source section for allowing light to enter from an end face between an upper substrate and a reflection layer will be described below. FIG. 3 is a schematic cross-sectional view of a reflective color liquid crystal display device provided with a light source unit using the LED light emitter of this embodiment as a light source. As shown in FIG. 3, the liquid crystal display element 1 is provided with a column electrode extending in the column direction by a transparent electrode, an upper substrate 11A, a pixel electrode 17 made of a transparent conductive film such as ITO, and a part thereof. MSI
And a lower substrate on which the element 19 is provided. The MSI element 19 includes a second electrode 14 made of an opaque conductive film, a semi-insulating film 15 and a row electrode 16 on a pixel electrode. The row electrode 16 is formed on the semi-insulating film 15 and extends in the row direction. Further, the upper substrate 11A and the lower substrate 11
B, the light modulation layer 2 is sandwiched between the lower substrate 11B and the transparent electrode 12B. The three primary color filters 3 of red, green, and blue are formed on the surface of the upper substrate 11A in contact with the light modulation layer. The reflective layer 4 and the insulating layer 5 are formed on the substrate. Note that the liquid crystal display element 1 was manufactured in the same configuration as in Example 1, and the cell gap was 10 μm.

Further, the LED light emitter 91 and the light source light guide 9
The light source unit 9 includes the light source unit 9 and the light from the LED light emitter 91 is efficiently condensed between the upper substrate 11A and the reflective layer 4 via the light source light guide 92. . Note that the upper substrate 11A is a transparent substrate that also serves as a light guide plate. In this embodiment, when external light is dark, the built-in light source unit 9 emits light, and the light is transmitted to the upper substrate 1 of the liquid crystal display element 1.
This is a reflection type color liquid crystal display device of an internally illuminated light scattering mode that realizes a bright display with good color reproduction by guiding light into the light modulation layer 1A and the light modulation layer 2.

Here, the end face of the liquid crystal display element 1 (however, the end face on which the light from the light source section 9 is incident is used so that the light guided through the upper substrate 11A and the light modulation layer 2 is effectively used. Excluding), an end face reflection layer 7 is provided. Next, the illumination effect of the internally illuminated type of this embodiment will be described below. Light emitted from the light source unit 9 is made incident from an end face between the upper substrate 11A and the reflective layer 4. Of the incident light, light forming an angle equal to or larger than the critical angle with the interface of the upper substrate 11A is confined between the reflection layer 4 and guided. When the light modulation layer 2 is in a transparent state, the guided light is
The light is guided as it is. Therefore, the observer cannot perceive light but perceives a dark display. On the other hand, when the light modulating layer 2 is in a transparent state, the guided light is scattered, and scattered light having an angle smaller than the critical angle is emitted from the upper substrate 11A to the outside.
The scattered light emitted to the outside enters the eyes of the observer. Thereby, the observer feels a bright display.

The LED luminous body 91 is a light source.
Whitening is performed by additive color mixing using three blue LED illuminants. This LED light emitter 91 is a light source light guide 92
Built inside. The light source light guide 92 is formed of white polycarbonate, and is optically adhered to one side surface of the present reflection type color liquid crystal display device. The light from the light source is designed so that it does not enter the lower part of the reflection layer 4 but is efficiently condensed and enters the end face of the liquid crystal display element 1.

By the way, since the LED light emitter is generally a colored light emitter, the light source is whitened using a mixture of three colors of red, green and blue in the above description. However, as another means, white light may be obtained by using a blue-violet LED light emitter as a light source and combining it with a fluorescent material having a wavelength conversion function of converting short-wavelength light into long-wavelength light. For example, Nichia
A blue-violet LED luminous body manufactured by NSCB100 and a yellow light-emitting phosphor NP-204 manufactured by Nichia Corporation were used as a white light source. Further, a light source such as a filament lamp, a krypton lamp, and an EL luminous body may be used. At this time, in the case of a filament lamp or a krypton lamp, a method of condensing light with a reflection case, and in the case of an EL luminous body, a method of directly adhering to a light incident surface of a light guide display device, etc., to efficiently use the method. Light is preferably incident on the liquid crystal display element 1.

Incidentally, even when the above various light sources are used,
A colored light source may be used by combining it with another emission color or using it as a monochromatic light source. In this case, the color balance and the color reproducibility are lost, but a color expression that enables an original and impressive design can be achieved. Further, a connection part for allowing light from the light source to enter the inside of the liquid crystal display element 1, for example, a light source light guide 92 or the like containing a light storage material may be used. As the light storage material, strontium aluminate SrAl2
A material obtained by adding a rare earth element using O2 as a mother crystal (manufactured by Nemoto Special Chemicals) or a compound obtained by adding a small amount of copper to zinc sulfide ZnS is preferable. Due to the effect of the light storage material, the above-described connection portion functions as an auxiliary light source, and emits light for a certain period of time even when the light source is turned off. In addition, the light-storing material can receive external light and store light energy by adopting a structure in which a portion such as the light source light guide 92 containing the light-storing material can receive external light.
Thereby, when the outside becomes dark, the self-luminous action of the light storage material eliminates the need for a battery and provides a bright display that is visible. Accordingly, a power-saving reflective color liquid crystal display device can be realized.

In this embodiment, the arrangement is such that light for illuminating the light source unit 9 is incident from an end face between the upper substrate 11A of the liquid crystal display element 1 and the reflective layer 4, but the light source itself is located inside the substrate. The structure provided may be sufficient. Also, the lower substrate 11
B is an active matrix type using an MSI element as an active element.
An active matrix type using an active element such as an element may be used. Further, the lower substrate 11B may be a pattern of only a simple matrix type or segment type transparent electrode.

Here, particularly in the case of a simple matrix or an active matrix, since electrodes are laid over almost the entire display screen, the electrodes formed on the lower substrate side are not made of transparent electrodes such as ITO, but are formed of a metal reflective layer. They may be combined. For example, after an aluminum film is formed on a lower substrate, it may be patterned into an electrode and used as an electrode. Of course, in this case, it is not necessary to provide a reflective layer separately.

The reflection type color liquid crystal display device provided with the light source unit for making light incident from the end face between the upper substrate and the reflection layer manufactured as described above has a structure in which the light of the light source is incident from the side. -Realizes a thinner reflective color liquid crystal display device compared to a structure in which a light source unit is installed above the display surface, such as a TN type liquid crystal display device that displays using two polarizing plates such as an LCD. We were able to.

Further, even when the external light is bright, by turning on the light source, the scattering intensity of the scattering portion where no voltage is applied can be increased, so that brighter and more vivid color reproduction can be achieved. Further, a reflection type color liquid crystal display device having high contrast was realized. Furthermore, by including a light storage material in the connection portion for allowing the light from the light source to enter the inside of the liquid crystal display device, the portion functions as an auxiliary light source, and the light source continues to emit light for a certain period of time even when the power of the light source is turned off. As a result, an energy-saving reflective color liquid crystal display device was realized. (Embodiment 5) An embodiment of a portable reflective color liquid crystal display device provided with a light source unit and a light guide plate will be described below.

FIG. 4 is a schematic sectional view of a portable reflective color liquid crystal display device having a light guide plate and a light source. FIG.
As shown in the figure, the liquid crystal display element 1 is provided with a column electrode extending in the column direction by a transparent electrode.
It comprises a pixel electrode 17 made of a transparent conductive film such as O and a lower substrate provided with an MSI element 19 on a part thereof. The MSI element 19 includes a second electrode 14 made of an opaque conductive film, a semi-insulating film 15 and a row electrode 16 on a pixel electrode. The row electrode 16 is formed on the semi-insulating film 15 and extends in the row direction. Further, the light modulation layer 2 is sandwiched between the upper substrate 11A and the lower substrate 11B, and the upper substrate 1
The three primary color filters 3 of red, green, and blue are formed on the side of the surface in contact with the light modulation layer 1A, and the lower substrate 11B and the transparent electrode 12 are formed.
This is a configuration in which a reflective layer 4 and an insulating layer 5 are formed between B. In addition, the liquid crystal display element 1 was prepared such that the cell gap was 10 μm. Note that the liquid crystal display element 1 was manufactured in the same configuration as in Example 1, and the cell gap was 10 μm.

Further, the LED light emitter 91 and the light source light guide 9
The light source unit 9 includes two light sources. The light source unit 9
It is electrically connected to the printed circuit board 83 and is in close optical contact with the light guide plate 93. Accordingly, the light from the LED light emitter 91 is efficiently focused on the light guide plate 93 via the light source light guide 92. Also, an end face of the light guide plate 93 (except an end face on which light from the light source unit 9 is incident) so that light guided in the light guide plate 93, the upper substrate 11A, and the light modulation layer 2 is effectively used. ) And an end face reflection layer 7 on the end face of the liquid crystal display element 1.

The printed circuit board 83 is electrically connected to the liquid crystal display element 1 via conductive rubber or a flat cable. Then, these element members (the liquid crystal display element 1, the printed circuit board 83, the light source unit 9, the light guide plate 93, and the battery (not shown)) are connected to the outer frame 81 and the back cover 82.
It is stored and held. The LED light emitter 91 is a light source,
Whitening is performed by additive color mixture using LED light emitters of three colors of red, green and blue. This LED light emitter 91 is incorporated in the light source light guide 92.

Accordingly, the reflective color liquid crystal display device of the portable type manufactured as described above performs bright and vivid color display when no voltage is applied, and black display when voltage is applied. It was confirmed. Therefore, it is possible to realize a new type of bright, high-contrast, portable color wrist-type reflective color liquid crystal display device with good color reproducibility, rich in information beyond the range of conventional digital watches. did it.

Further, since the light source section is arranged on the side surface of the liquid crystal display element, the thickness of the reflection type color liquid crystal display device including the light source section can be further reduced. Furthermore, even when the external light is bright, by turning on the light source, the scattering intensity of the scattering portion where no voltage is applied can be increased, so that brighter and more vivid color reproduction can be achieved.
In addition, a reflection type color liquid crystal display device having high contrast was realized.

In this embodiment, the light source 9 and the light guide plate 93 are provided.
Are combined to make the light for illumination of the light source unit 9 incident from the end face of the light guide plate 93, but the light source itself may be arranged in the light guide plate 93. here,
As the light modulation layer 2, a light scattering type liquid crystal layer of a reverse mode in which a transparent state occurs when no voltage is applied and a light scattering state occurs when a voltage is applied may be used.

In this case, the area of the scattering portion occupying the entire display screen is determined by the PN-LC layer (that is, the light scattering state when no voltage is applied, and the transparent state when voltage is applied). The area is considerably smaller than that in the case of using. Therefore, when the same irradiation light amount is incident from the light source unit 9, the scattered portion in the reverse mode is significantly brighter than the scattered portion of the normal node.
Therefore, by using the light scattering layer 2 in the reverse mode, the contrast ratio between the scattering portion and the transparent portion becomes much higher than the contrast ratio in the normal mode, and a better display quality can be obtained. (Embodiment 6) In this embodiment, a reflection type liquid crystal display device of a passive matrix type (three-division drive) will be described below. As shown in FIG. 13, the liquid crystal display element 1
A pair of transparent substrates (upper and lower substrates) 11A and 11B having transparent electrodes 12A and 12B patterned for divided driving (1/3 duty, 1/3 bias driving); The light modulating layer 2 is sandwiched between the lower substrate 11B and the transparent electrode 12B. And a reflective layer 4 and an insulating layer 5 formed therebetween. The liquid crystal display element 1 was prepared so that the cell gap was 10 μm.

In this embodiment, a smooth and transparent glass plate was used as the transparent substrates 11A and 11B. The transparent substrate 1
For 1A and 11B, a transparent polymer film other than a smooth and transparent glass plate may be used. Transparent electrode 12A, 1
In this embodiment, an In2O3-SnO2 film (hereinafter referred to as ITO) formed by a sputtering method or a vacuum evaporation method is used as 2B.
A transparent conductive film formed by photolithography was used. Although the resistance value of the ITO can be freely adjusted as needed, in this embodiment, the sheet resistance of both the transparent conductive films 12A and 12B is set to 20Ω / □. The transparent electrodes 12A and 12B may use an SnO2 film in addition to the ITO film.

The reflection layer 4, the light modulation layer 2, and the RGB color filter 3 were manufactured in the same configuration as in the first embodiment. Here, the RGB color filter 3 has a transmittance of a specific wavelength (365 nm) of each color filter of red = 40% and green = 25.
%, Blue = about 35% by adjusting the average particle size when the pigment is dispersed and the film thickness of each color filter. Also,
The light modulating layer 2 has an ultraviolet irradiation intensity for causing phase separation of the liquid crystal / polymer precursor mixed solution at a point F (inflection point) +50.
The liquid crystal / polymer precursor was irradiated with ultraviolet rays at a value of mW / cm ² to form a light modulation layer having a polymer network structure.

By manufacturing in this way, the voltage characteristics (Vth, Vth,
sat, steepness) can sufficiently satisfy the operation margin of the passive matrix type (three-division driving). The red-green-green-dispersion color liquid crystal display element 1 of the polymer network type polymer dispersion mode produced in this way is shown.
When the light modulation layer 2 corresponding to the blue color filter 3 was observed using a scanning electron microscope, a three-dimensional network structure (polymer network structure) composed of a polymer was confirmed. The three-dimensional network has an average pore size of about 1.
It was around 0 μm.

The light modulation layer 2 corresponding to the red, green, and blue color filters 3 of the reflection type color liquid crystal display element is
It was confirmed that each of the light modulating layers was excellent in light scattering characteristics, was significantly reduced in voltage, and was a scattering mode light modulation layer having low hysteresis characteristics. Further, a color filter 3 and a reflection layer 4 are provided on the inner surface of the color liquid crystal display element 1.
Is formed, no parallax (double reflection) is generated, and accordingly, there is no problem such as a decrease in brightness or a deterioration in color purity due to the parallax.

The reflection type color liquid crystal display device is
When driven at 1/3 Duty and 1/3 Bias, no crosstalk occurs when not selected (Voff), and when selected (Von), a bright and clear display with good visibility is obtained. , Practically usable contrast (1:
5), and the color display quality of vivid color reproduction and good color balance was confirmed. The reflective color liquid crystal display device displays a color by a color filter when no voltage is applied, and displays black when a voltage is applied.

[0118]

As described above, according to the reflection type color liquid crystal display device of the present invention, each color filter is used in a color filter system in which one pixel is divided by a plurality of color filters and color is displayed. Has a function of transmitting ultraviolet light of a specific wavelength, and limits the transmittance of the ultraviolet light between the color filters to 2.5 times or less. Variations in basic characteristics such as light scattering state (white turbidity), voltage characteristics (threshold voltage, saturation voltage, steepness, etc.) and response speed of a light modulation layer corresponding to each color filter in a pixel are determined. The range can be kept low. As a result, it is possible to provide a reflective color liquid crystal display device which realizes high-quality display quality, which is brighter than before, and has high contrast and excellent color reproducibility.

Further, since a polymer-dispersed liquid crystal layer having a polymer network structure (three-dimensional network structure) is used as the light modulating layer, good light scattering (white turbidity) and drastic low voltage driving are simultaneously realized. As a result, it has become possible to provide a low-power-consumption type liquid crystal display device of a bright reflective portable information device that has a longer life than the conventional one.

Further, since the structure in which the color filter and the reflection layer are arranged on the inner surface of the liquid crystal display element is adopted, it is possible to provide a reflection type color liquid crystal display device with good color reproducibility, which eliminates the problem of double reflection. It became. In addition, it is possible to improve the visibility of display contents due to reflection of external light and prevent deterioration of the light modulation layer due to ultraviolet rays, thereby providing a highly reliable reflective color liquid crystal display device. Was.

The light source unit provided inside the reflection type color liquid crystal display device has a structure in which light enters from the end face of the liquid crystal display element, or a light source in which light enters from the end face of a light guide plate closely mounted on a color filter. Because of this structure, the color of the color filter can be faithfully reproduced even in a dark place such as at night, and a thin reflective color liquid crystal display device that is bright and has good contrast can be provided.

The color filter used in the present invention can be manufactured by a general color filter manufacturing method such as a pigment dispersion method or a dyeing method. Therefore, a low-cost color filter can be provided. In addition, since a polymer-dispersed liquid crystal layer having a polymer network structure (three-dimensional network structure) that does not require alignment processing is used as the light modulation layer, flattening processing and alignment processing of a color filter are not required. The process can be simplified and a low-cost liquid crystal display device can be provided.

Further, a MIS element as an active element,
By using an active matrix such as a MIM element or a TFT element, a reflective color liquid crystal display device which is bright, has excellent color reproduction, and realizes display quality with good contrast can be provided. Even when a simple matrix is used as a passive element (transparent electrode) and time-division driving (multiplex driving) is performed, no crosstalk occurs during non-selection (Voff) and bright when selection (Von). ,
It is possible to provide a reflective color liquid crystal display device which is excellent in color reproduction and realizes display quality with good contrast.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic structure of a reflective color liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a schematic structure of a reflective color liquid crystal display device according to a second embodiment of the present invention.

FIG. 3 is a schematic sectional view of a reflective color liquid crystal display device including a light source unit according to a fourth embodiment of the present invention.

FIG. 4 is a schematic sectional view of a portable reflective color liquid crystal display device according to a fifth embodiment of the present invention.

FIG. 5 is a schematic diagram of a color filter end overlapping structure according to the present invention.

FIG. 6 is a schematic diagram of a color filter end overlapping structure according to the present invention.

FIG. 7 is a configuration diagram (a four-color configuration of red, green, blue, and transparent) of a color filter according to a third embodiment of the present invention.

FIG. 8 is a configuration diagram of a color filter according to a third embodiment of the present invention (four-color configuration of red, green, blue, and transparent).

FIG. 9 is a graph showing the relationship between the UV irradiation intensity of the PN-LC layer and the light scattering property (white turbidity).

FIG. 10 is a graph showing the relationship between the UV irradiation intensity of the PN-LC layer and the voltage characteristics of the liquid crystal.

FIG. 11 is a graph showing a relationship between a driving voltage of an MSI element and an effective voltage of a liquid crystal.

FIG. 12 is a reflection spectrum of the surface of a transparent substrate on which an antireflection layer and an ultraviolet blocking layer are arranged in Example 2 of the present invention.

FIG. 13 is a sectional structural view of a reflective color liquid crystal display device according to a sixth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal display element 2 Light modulation layer 3 RGB color filter 4 Reflection layer 5 Insulation layer 61 Antireflection layer 62 Ultraviolet shielding layer

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification code FI G02F 1/136 505 G02F 1/136 505 G09F 9/35 320 G09F 9/35 320 (72) Inventor Naoshi Shino Mihama, Chiba City, Chiba Prefecture 1-8-8 Nakase-ku, Seiko Instruments Inc. (72) The inventor Hiroshi Sakuma 1-8-8 Nakase, Mihama-ku, Chiba-shi, Chiba In-house Seiko Instruments Inc. (72) The inventor Takakazu Fukuchi Mihama-ku, Chiba 1-8-8 Nakase, Seiko Instruments Inc. (72) Inventor Teruo Ebihara 1-8-8 Nakase, Mihama-ku, Chiba-shi, Chiba In-house Seiko Instruments Inc. (72) Inventor Shunichi Monobukuro, Nakase, Mihama-ku, Chiba 1-8-8 Seiko Instruments Inc. (72) Inventor Shigeru Chihonmatsu 1-8 Nakase, Mihama-ku, Chiba-shi, Chiba Seiko Instruments Inc. (72) Inventor Kaoru Taniguchi 1-8-8 Nakase, Mihama-ku, Chiba-shi, Chiba Seiko Instruments Inc. (72 Inventor Shuhei Yamamoto 1-8-8 Nakase, Mihama-ku, Chiba-shi, Chiba Inside Seiko Instruments Inc. (72) Inventor Masanori Fujita 4-9-1, Taihei, Sumida-ku, Tokyo Seiko Precision Co., Ltd.

Claims (19)

[Claims] A transparent substrate on which a transparent electrode is formed; a counter substrate provided to face the transparent substrate; a light modulation layer provided between the pair of substrates facing each other; A color filter provided on the surface side in contact with the light modulation layer, and having a spectral characteristic of transmitting light in a specific wavelength range in the visible light region and ultraviolet light in a specific wavelength range necessary for ultraviolet curing of the polymer-dispersed liquid crystal layer. And a reflective layer provided on the surface of the counter substrate that is in contact with the light modulation layer, and the light modulation layer exhibits a light scattering state when no voltage is applied and a transparent state when a voltage is applied. A polymer-dispersed liquid crystal layer having a three-dimensional network-shaped photocurable resin in a continuous layer formed of liquid crystal, wherein the color filters are two or more types that transmit different visible lights on the same plane. Paternin in the area Together are reflective liquid crystal display device, characterized in that the ultraviolet transmittance in a specific wavelength range of the color filters are patterned is not more than 2.5 times between the color filters from each other. 2. The reflection type liquid crystal display device according to claim 1, wherein the color filter comprises a combination of red, green, blue and transparent, or a combination of yellow, magenta, cyan and transparent. 3. The color filter according to claim 1, wherein the color filter comprises a combination of red, green, and blue, or yellow, magenta, and cyan, and at least one color filter includes a transparent portion in the color filter region. The reflective liquid crystal display device according to claim 1. 4. The reflective liquid crystal display device according to claim 1, wherein the end portions of the color filters overlap each other with a predetermined width. 5. A colored photosensitive resist, wherein the color filter has an average particle size of 0.09 μm or less when the pigment is dispersed,
5. The reflection type liquid crystal display device according to claim 1, wherein the reflection type liquid crystal display device is a color filter using a dye as a coloring material. 6. The reflection layer is a metal or dielectric multilayer film containing at least one of a metal such as aluminum, silver, nickel, chromium, palladium, rhodium, an alloy thereof, and an oxide thereof. 2. The reflective liquid crystal display device according to claim 1, wherein: 7. The reflection type liquid crystal display device according to claim 1, wherein the electrode has a function of a reflection layer. 8. The device according to claim 1, wherein an active element and a pixel electrode connected to the active element are formed on the counter substrate, and a reflective layer is formed behind the pixel electrode. Reflective liquid crystal display device. 9. The reflection type liquid crystal display device according to claim 8, wherein the active element is an MSI element (metal-semi-insulating film-metal). 10. The reflection type liquid crystal display device according to claim 1, wherein an antireflection layer and an ultraviolet blocking layer absorbing or reflecting ultraviolet rays harmful to the liquid crystal are disposed on the electrode surface. 11. A color filter manufacturing step of forming a color filter having a spectral characteristic of transmitting light in a specific wavelength range in a visible light range and ultraviolet light in a specific wavelength range necessary for curing a polymer-dispersed liquid crystal on a transparent substrate. Forming a reflective layer on a counter substrate, bonding the transparent substrate and the counter substrate to a predetermined gap with a sealant, injecting a mixture of liquid crystal and a polymer precursor into the gap, In order to form a light modulation layer by polymerizing the molecular precursor and phase-separating the liquid crystal and the polymer, a UV light is applied from the transparent substrate side at a UV irradiation intensity at which a threshold voltage higher than the inflection point of the threshold voltage of the liquid crystal is obtained. And a UV irradiation step of irradiating the liquid crystal display device. 12. In the color filter manufacturing step, the ultraviolet transmittance of the color filter in a specific wavelength range is:
The thickness of the color filter, the average particle size of the color material, or the concentration of the color material is relatively adjusted between the color filters so that the intensity of the ultraviolet light applied in the ultraviolet irradiation step is 2.5 times or less. 2. The method according to claim 1, wherein
2. The method for manufacturing a reflective liquid crystal display device according to item 1. 13. The reflection type as claimed in claim 11, wherein in the step of producing a color filter, a colored photosensitive resist or a dye having an average particle size of 0.09 μm or less when the pigment is dispersed is used. A method for manufacturing a liquid crystal display device. 14. The method according to claim 11, wherein in the step of irradiating the ultraviolet ray, the mixture of the liquid crystal and the polymer precursor is maintained at a temperature at which the mixture exhibits an isotropic phase. . 15. The temperature at which the isotropic phase is exhibited is maintained at a temperature higher by 1 ° C. to 3 ° C. than the nematic isotropic phase transition temperature (NI point) of the mixture of the liquid crystal and the polymer precursor. The method of manufacturing a reflective liquid crystal display device according to claim 14, wherein: 16. The method as claimed in claim 11, wherein in the step of irradiating the ultraviolet ray, the ultraviolet ray is irradiated through a filter having an ultraviolet scattering property. 17. The reflection type according to claim 11, further comprising a step of disposing an antireflection layer and an ultraviolet blocking layer for absorbing or reflecting ultraviolet rays harmful to the liquid crystal on the transparent substrate after the ultraviolet irradiation step. A method for manufacturing a liquid crystal display device. 18. A reflective liquid crystal display device in which a light modulation layer is sandwiched between a pair of substrates each having at least one transparent electrode, wherein the light modulation layer exhibits a light scattering state when no voltage is applied. ,
A polymer-dispersed liquid crystal layer that exhibits a transparent state when a voltage is applied. The polymer-dispersed liquid crystal layer forms a continuous layer of liquid crystal material, and has a three-dimensional network-like photocurable resin in the continuous layer. A color filter is formed on a surface of the upper substrate of the reflection type liquid crystal display device which is in contact with the light modulation layer, and a reflection layer is formed on a surface side of the lower substrate of the reflection type liquid crystal display device which is in contact with the light modulation layer. A reflection type liquid crystal display device further comprising a light source unit for making light incident from an end face between the upper substrate and the reflection layer. 19. A reflective liquid crystal display device in which a light modulation layer is sandwiched between a pair of substrates at least one of which has a transparent electrode, wherein the light modulation layer exhibits a light scattering state when no voltage is applied. ,
A polymer-dispersed liquid crystal layer that exhibits a transparent state when a voltage is applied. The polymer-dispersed liquid crystal layer forms a continuous layer of liquid crystal material, and has a three-dimensional network-like photocurable resin in the continuous layer. A color filter is formed on a surface of the upper substrate of the reflection type liquid crystal display device which is in contact with the light modulation layer, and a reflection layer is formed on a surface side of the lower substrate of the reflection type liquid crystal display device which is in contact with the light modulation layer. A reflection type liquid crystal display device, comprising: a light guide plate formed of a transparent member in close contact with the outside of the upper substrate; and a light source unit for allowing light to enter from an end face of the light guide plate.