JPH11119206A - Reflection type color liquid crystal display device and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a reflection layer possible to adjacent to a liquid crystal layer, to eliminate a doubly seen display and to enable bright color display, by irradiating a light molecule- dispersed liquid crystal layer with UV rays from the front surface substrate side, then arranging a transparent sustrate opposite to the front surface substrate via an air layer. SOLUTION: Transparent electrodes 4 for display are formed on the front surface of the front surface substrate 1 and pixel electrodes 5 for display in common use as the reflection layer are formed on the surface of the rear surface substrate 2. The high molecular material dispersed liquid crystal layer 3 held between the substrates is formed by irradiating a soln. mixture composed of liquid crystals and a high molecule precursor, such as acryl monomer, with UV rays to cause a phase sepn., and to fill the liquid crystals in the network spacings of the high-polymer resin. The front surface of the transparent substrate 6 is provided with the red, green and blue color filters 7r, 7g, 7b as the color filters according to the positions of the transparent electrodes 4 for display and the pixel electrodes 5 for display. The color filter forming surface and the front surface substrate 1 face each other via the air layer 8. The pixel electrodes 5 for display in common use as the light reflection layer are disposed adjacently behind the high molecular material-dispersed liquid crystal layer 3 so that the display is not visible in double and the bright display is obtd. even when the display is viewed from a diagonal direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a reflective color liquid crystal display device and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, as a display device for a portable information device,
A light-scattering type liquid crystal display device is being developed aiming at a reflective and bright display device. Above all, Japanese Patent Application Laid-Open No. 8-1848
As shown in FIG. 6, a reflective type color liquid crystal display device disclosed in Japanese Patent Application Publication No.
3 and a color filter 104 disposed on the front side thereof
r, 104g, 104b, and a light reflecting plate 106 provided behind the rear substrate 102.
The conventional reflection type color liquid crystal display device performs color display by such a combination, and has been proposed as a method capable of low voltage driving and low power consumption, and capable of bright display because no polarizing plate is used. . In the figure, 101 and 102 are substrates, and 105 and 107 are transparent electrodes.

[0003]

In such a polymer-dispersed liquid crystal display device, since ultraviolet light must be irradiated to separate the liquid crystal and the polymer resin, a light reflection layer is formed on the outside of the rear substrate. Is provided. That is, after irradiating ultraviolet light from the rear substrate side, the light reflection layer is formed.

Therefore, as shown in FIG. 6, an interval corresponding to the thickness of the rear substrate 102 is generated between the polymer dispersed liquid crystal 103 and the light reflecting plate 106, and the pixel interval is different from that of a display device for a portable information device. In the case of a small size, there is a problem that when viewed from an oblique direction, the display becomes double and it becomes difficult to see. In addition, when used in a dark place such as at night, the display becomes dark, so illumination is required. If a backlight generally used in the configuration shown in FIG. 6 is to be used as illumination, the light reflecting plate 106 must be a translucent mirror such as a half mirror. In this case, when the light is used in the reflection type in which the illumination is not turned on, the reflection efficiency is deteriorated as compared with the case where the light reflection plate is used as shown in FIG. Further, even when the backlight is used, the diffused light is incident, and almost no contrast can be obtained.

[0005] A method of irradiating light from the side of a light scattering type liquid crystal display device without using a backlight is also conceivable.
However, in this case, since the irradiated light is absorbed by the color filter, there is a problem that the light incident from the side does not reach the center of the display surface and the entire display surface cannot be illuminated brightly.

[0006]

According to the present invention, a transparent substrate having a color filter is provided separately from the front substrate. Therefore, after irradiating the polymer-dispersed liquid crystal layer with ultraviolet rays from the front substrate side, the transparent substrate is exposed to air. The display device can be configured to be arranged to face the front substrate via the layer. That is, since it is not necessary to irradiate ultraviolet rays from the rear substrate side, the reflection layer can be adjacent to the liquid crystal layer, and double reflection can be eliminated. Therefore,
Clear color display is possible.

If the reflection layer also serves as the counter electrode formed on the rear substrate, the structure can be simplified, and the size and cost of the structure can be reduced. If red, blue, and green color filters are used as color filters, and the color filters of those colors are arranged in a vertical stripe having the same color in the vertical direction of the display surface of the reflective color liquid crystal display device,
The color blur in the vertical direction of the display surface can be reduced.

[0008] The transparent substrate may also serve as a part of the components of the touch panel type input device. In this case, since a part of the transparent substrate used for the touch panel and the transparent substrate provided with the color filter can be shared, the configuration can be simplified, and the configuration can be reduced in size and the cost can be reduced. Furthermore, by providing an illuminating device that allows light to enter from the side surface of the front substrate, the illuminating light is not absorbed by the color filter while traveling while reflecting between the air layer and the reflective layer, and the entire display surface is prevented. Can be brightly illuminated.
Therefore, it can be used in a dark place such as at night. further,
Even if illumination is performed in a bright place, the external light and the illumination light work in cooperation with each other, so that the brightness can be further increased and an easy-to-view display can be performed.

If the rear substrate and the lighting device are provided on the same circuit board, a conductor for electrically connecting the circuit board and the lighting device is not required, and the size can be reduced. Further, a lighting device may be provided on a holding member for holding the liquid crystal panel on the circuit board. In addition, a step of injecting a liquid mixture of a liquid crystal and a polymer precursor into a gap between the front substrate and the rear substrate where the respective electrodes are arranged so as to face each other, and irradiating ultraviolet light from outside the front substrate with the liquid crystal A step of phase-separating the polymer resin;
A step of arranging a transparent substrate having a color filter and a front substrate to face each other via an air layer after the phase separation, so that even after forming the reflective layer inside the rear substrate in advance, the front substrate The dispersion liquid crystal can be formed by irradiating ultraviolet light from the side to phase-separate the liquid crystal and the polymer precursor. Therefore, the distance between the liquid crystal layer and the reflective layer can be eliminated, and the display does not look double even when viewed from an oblique direction, and a bright and clear reflective color display can be achieved.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a display device according to the present invention, a liquid crystal layer provided between electrodes formed on a front substrate and a rear substrate, a reflective layer provided between the rear substrate and the liquid crystal layer, A transparent substrate provided with a color filter is provided, and the transparent substrate and the front substrate face each other via an air layer. Therefore, double reflection can be eliminated, and a clear color display can be realized.

[0011] In the manufacturing method, the front substrate on which the first electrode is formed and the rear substrate on which the second electrode and the reflective layer are formed are opposed to each other by the electrodes formed on the respective substrates. Holding the liquid crystal and the polymer precursor in the gap between the substrates, and irradiating ultraviolet rays from outside the front substrate to separate the liquid crystal and the polymer resin. And a step of, after the phase separation, arranging the transparent substrate provided with the color filter so as to face the front substrate via an air layer.
That is, even after the reflection layer is formed inside the back substrate in advance, the dispersion type liquid crystal can be formed by irradiating ultraviolet light from the front substrate side. Therefore, the distance between the liquid crystal layer and the reflective layer can be eliminated, and the display does not look double even when viewed from an oblique direction, and a liquid crystal device with bright and clear color display can be manufactured.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. (Embodiment 1) FIG. 1 is a sectional view showing a schematic configuration of a reflection type color liquid crystal display device according to an embodiment of the present invention.

As shown in FIG. 1, a display transparent electrode 4 is formed on the surface of a front substrate 1 which is a transparent substrate made of glass or the like, and a reflective electrode 4 is formed on the surface of a rear substrate 2 which is a transparent substrate made of glass or the like. A display pixel electrode 5 also serving as a layer is formed. The display pixel electrode 5 also serves as a reflective layer and an electrode, and is formed of a conductive metal having high reflectivity such as aluminum or silver.

The polymer-dispersed liquid crystal layer 3 sandwiched between these substrates is irradiated with ultraviolet light to irradiate a mixed solution of a liquid crystal and a polymer precursor such as an acrylic monomer with ultraviolet light to form a network of polymer resin. Is filled with liquid crystal. In this example, the thickness of the liquid crystal layer is about 8 microns, and the transparent state and the scattering state are controlled by applying an electric field. As the polymer-dispersed liquid crystal, either a liquid crystal which is scattered when no electric field is applied and becomes transparent when an electrolysis is applied, or a liquid crystal which is transparent when no electric field is applied and becomes a scattered state when an electrolysis is applied, and there is no particular limitation.

On the surface of a transparent substrate 6 made of glass or the like,
As the color filter 7, a red color filter 7r, a green color filter 7g, and a blue color filter 7b are provided in accordance with the positions of the display transparent electrode 4 and the display pixel electrode 5. The surface of the transparent substrate 6 on which the color filters 7 are formed and the front substrate 1 are arranged to face each other with an air layer 8 interposed therebetween. The color filter 7 is red,
The vertical stripes are arranged so that each color of green and blue becomes the same color in the vertical direction of the display surface.

As described above, since the display pixel electrode 5 which also functions as a light reflection layer is provided adjacent to the rear of the polymer dispersed liquid crystal layer 3, the display can be seen double even when viewed from an oblique direction. There is no clear display. Further, since the reflective layer also serves as a display pixel electrode, the configuration can be simplified, and the configuration can be reduced in size and cost can be reduced.

Since the front substrate and the air layer are provided between the liquid crystal layer and the color filter, there is a space between the liquid crystal layer and the color filter. This causes a problem that bleeding easily occurs. In general, for personal information terminal display applications, display is rarely viewed from the left and right directions (horizontal direction) of the display surface, and a vertical viewing angle is required. Therefore, in the above example, by arranging the color filters of each color in the vertical stripe so as to be the same color in the vertical direction of the display surface, the color blur in the vertical direction of the display surface is reduced, and the user can actually To prevent the display quality from deteriorating. That is, the color bleeding problem is solved by the arrangement of the color filters 7r, 7g, 7b.

Further, since the color filter is not adjacent to the liquid crystal layer, restrictions on the color filter, for example, restrictions on the surface roughness of the color filter are reduced, and inexpensive materials such as printing and color filters formed by a manufacturing method are used. Can be used. Instead of the display pixel electrode 5 also serving as the light reflection layer, the light reflection layer and the display pixel electrode may be separately laminated and provided on the rear substrate.

Hereinafter, the manufacturing method will be described. First, the front substrate 1 on which the display transparent electrodes 4 are formed in a pattern
And a back substrate 2 in which a conductive metal electrode having high reflectivity such as aluminum or silver is patterned as a light reflection layer and display pixel electrode 5 with the electrodes 4 and 5 facing each other,
A spacer (not shown) is arranged in the meantime, and the outer periphery of the substrate is adhered with a sealing material 10 described later, leaving an injection port (not shown), thereby creating an empty cell with a gap of 8 microns.

Next, a mixed solution of liquid crystal and a polymer precursor such as an acrylic monomer is vacuum-injected into the empty cell from the injection port, and the injection port is sealed. Then, while controlling the whole at a constant temperature (preferably about 1.5 ° C. of the liquid crystal phase transition temperature), 75 mW / cm 2 UV light is irradiated from outside of the front substrate 1 with a metal halide lamp for 20 seconds. The liquid crystal and the polymer resin are phase-separated to form a polymer-dispersed liquid crystal. Note that the ultraviolet irradiation conditions are not limited to these, and may be changed as appropriate.

Thereafter, the color filter 7 includes a transparent substrate 6 in which a red color filter 7r, a green color filter 7g, and a blue color filter 7b are arranged in a vertical stripe so as to have the same color in the vertical direction of the display surface. The formed surface is opposed to the front substrate 1, and a spacer (not shown) for providing an air layer 8 is disposed between them, and the color filters 7 of each color are used as the display transparent electrode 4 and the reflection layer / display. The outer periphery is adhered to the position corresponding to the position of the pixel electrode 5 with an adhesive 11 or an adhesive tape described later.

According to this manufacturing method, uniform ultraviolet light can be irradiated over the entire surface, so that variations in display characteristics can be reduced. Further, in the case of the conventional example as shown in FIG. 6, since the light absorption type color filter and the light reflection layer cannot transmit the ultraviolet light, the light reflection layer must be provided on the back surface of the substrate. There was a problem that it looked double. However, in this embodiment, the light reflection layer can be provided inside the cell, and a clear display can be achieved without a double display.

Further, since the color filter is not adjacent to the liquid crystal layer, restrictions on the color filter, for example, restrictions on the surface roughness of the color filter are reduced, and inexpensive materials such as printing and a color filter formed by a manufacturing method are used. Can be used. (Embodiment 2) FIG. 2 shows an example in which an illuminating means for internal illumination is provided in Embodiment 1.

Light is incident on the side surface of the front substrate 1 using an illumination device 9 constituted by a white chip LED or the like. The light that has entered the front substrate 1 travels while repeating reflection at the interface between the front substrate 1 and the air layer 8 and between the display pixel electrodes 5 also serving as a reflection layer. At this time, since the color filter 7 does not exist on the optical path, light is not absorbed by the color filter 7 and illumination light can be used effectively. Therefore,
It can be used in dark places such as at night. Further, even when lighting is performed in a bright place, the external light and the illuminating light work in cooperation with each other, so that the brightness can be further increased and an easy-to-view display can be performed. Therefore, the lighting may be always turned on, or may be turned on as needed.

The front substrate 1 on which the lighting device 9 is provided
If a light reflection surface is provided on the opposite side of the side surface, illumination light can be used more effectively, so the brightness can be further increased,
Easy-to-read display can be performed. In the figure, reference numeral 10 denotes a sealant, 11 denotes an adhesive, and the same components as those in FIG.

(Embodiment 3) FIG. 3 is a diagram showing an example in which the configuration of Embodiment 2 is provided on a circuit board. As shown in FIG. 3, the rear substrate 2 side is disposed on the circuit board 12, and the chip LED is mounted on the circuit board 12 so that the light emitting portion of the chip LED of the lighting device 9 is located at a position corresponding to the side surface of the front substrate 1. Surface mount on top. Specifically, the height from the bottom of the chip LED to the light-emitting portion is matched with the height from the back substrate 2 to the center of the front substrate 1 of the liquid crystal panel, and this is set to the same circuit board 1
2 is provided. In the figure, the same reference numerals as those in FIGS.

If the rear substrate 2 and the chip LED are provided on the same circuit board 12 as described above, the circuit board 12 and the chip L
A conductor for electrically connecting to the ED is not required, and downsizing can be realized. Further, if a plurality of chip LEDs are appropriately arranged on both sides of the liquid crystal panel according to the size of the display surface, a brighter display can be achieved. Further, in this case, if a light reflecting surface is provided at a portion other than the light incident portion of the chip LED on the side surface of the liquid crystal panel, and the chip LEDs on both sides are arranged to be shifted from each other so as not to face each other, the illumination light can be used effectively, so that it is more visible Display can be performed.

(Embodiment 4) FIG. 4 shows an example in which the configuration of the embodiment 2 is arranged on a circuit board as in FIG. In FIG. 3, the chip LED 9 is formed on the circuit board 12, but in this embodiment, the chip LED, which is the lighting device 9, is connected via the flexible circuit board 14 to the front substrate 1, the rear substrate 2, the liquid crystal layer 3, A liquid crystal panel including a transparent electrode 4 and a display pixel electrode 5 also serving as a reflective layer is provided on a holding member 13 that holds the liquid crystal panel on a circuit board 12. The holding member 13 is fixed to the circuit board 12 by screws or the like, and covers the outer peripheral portion of the liquid crystal panel. Also in this example, similarly to the third embodiment, a plurality of chip LEDs may be appropriately arranged on both sides of the liquid crystal panel according to the size of the display surface. In this case, a plurality of chip LEDs are provided in advance on a flexible circuit board 14 formed in accordance with the size of the surface of the holding member 13 facing the side surface of the liquid crystal panel, and the plurality of chip LEDs are mounted on the holding member 1.
If the third liquid crystal panel is provided on the surface facing the side surface, the production becomes easy. Further, if a light reflecting surface is provided on the surface of the holding member 13 facing the side surface of the liquid crystal panel, brighter display is possible. In the figure, the same reference numerals as those in FIGS.

In the second to fourth embodiments, the illumination light is directly incident on the side surface of the front substrate 1. However, a reflection plate having an inclined surface is disposed on the side surface of the front substrate 1, and light is irradiated from below. Alternatively, the light may be reflected by the reflection plate to make the light incident on the side surface of the front substrate 1. (Embodiment 5) FIG. 5 shows another embodiment having no illumination combined with an active element. In FIG. 5, the same reference numerals as those in FIG. 1 denote the same elements. Back substrate 2
Are provided with active elements 15 such as MIM, MSI, and TFT. By including the active element, the display capacity of a portable information display device or the like can be increased. The active element may be provided on the front substrate 1 side. Further, the illumination as described in the second embodiment may be performed on this.

In each of the embodiments shown in FIGS.
The transparent substrate 6 may also serve as a part of a component of the touch panel type input device. In this case, the entire thickness including the touch panel type input device can be reduced, the configuration can be simplified, and the cost can be reduced. Further, the transparent substrate 6 may be configured to also serve as the transparent opening of the case of the portable device, whereby the overall thickness can be reduced, the configuration can be simplified, and the cost can be reduced.

[0031]

According to the present invention, the reflection layer can be configured to be adjacent to the liquid crystal layer, and double reflection can be eliminated. Therefore, clear color display is possible. further,
Since the color filter is not adjacent to the liquid crystal layer, restrictions on the color filter, for example, restrictions on surface roughness and the like are reduced, and a color filter formed by an inexpensive material such as printing or a manufacturing method can be used.

If the liquid crystal layer is a polymer-dispersed liquid crystal layer, a bright display can be achieved. If the reflection layer also serves as the counter electrode formed on the rear substrate, the configuration can be simplified,
The structure can be reduced in size and cost can be reduced. Using red, blue and green color filters as color filters,
By arranging the color filters of the respective colors in the vertical stripes of the same color in the vertical direction of the display surface of the reflection type color liquid crystal display device, it is possible to reduce the color blur in the vertical direction of the display surface.

The transparent substrate may also serve as a part of the configuration of the touch panel type input device. In this case, since a part of the transparent substrate used for the touch panel and the transparent substrate provided with the color filter can be shared, the configuration can be simplified, and the configuration including the touch panel type input device can be reduced in size and cost can be reduced. . A liquid crystal layer is interposed between the counter electrodes formed on the front substrate and the rear substrate, a reflective layer is provided between the rear substrate and the liquid crystal layer, and a transparent electrode having a color filter is provided on the front substrate via an air layer. Light is incident on the side of the front substrate in the liquid crystal panel arranged opposite to the light source by the illumination means, so that the illumination light is not absorbed by the color filter while traveling while reflecting between the air layer and the reflective layer. The whole display surface can be brightly illuminated. Therefore, it can be used in a dark place such as at night. Further, even when lighting is performed in a bright place, the external light and the illuminating light work in cooperation with each other, so that the brightness can be further increased and an easy-to-view display can be performed.

If the rear substrate and the illuminating means are formed on the same circuit board, a conductive wire for electrically connecting the circuit board and the illuminating means is not required, and the size can be reduced. Even after the reflective layer is formed inside the substrate in advance, the dispersed liquid crystal can be formed by irradiating ultraviolet light from the front substrate side to phase-separate the liquid crystal and the polymer precursor, so that the liquid crystal layer and the reflective layer can be formed. The gap can be eliminated, and the display does not look double even when viewed from an oblique direction, and a bright and clear reflective color display can be performed.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is a sectional view of another embodiment of the present invention.

FIG. 3 is an explanatory view of another embodiment of the present invention.

FIG. 4 is an explanatory view of another embodiment of the present invention.

FIG. 5 is a sectional view of another embodiment of the present invention.

FIG. 6 is a sectional view of a conventional reflective color liquid crystal display device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 front substrate 2 back substrate 3 liquid crystal layer 4 display transparent electrode 5 display pixel electrode also serving as reflective layer 6 transparent substrate 7 color filter 8 air layer 9 lighting device 12 circuit board 13 holding member

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Teruo Ebihara 1-8-8 Nakase, Mihama-ku, Chiba-shi Inside Seiko Instruments Inc. (72) Inventor Kaoru Taniguchi 1-8-chome Nakase, Mihama-ku, Chiba-shi, Chiba Inside Iko Instruments Co., Ltd. (72) Inventor Shigeru Chimotomatsu 1-8-1, Nakase, Mihama-ku, Chiba-shi, Chiba In-house Incorporator (72) Takakazu Fukuchi 1-8-1, Nakase, Nakase, Mihama-ku, Chiba-shi, Seiko In Instruments Co., Ltd. (72) Inventor Hiroshi Sakuma 1-8-1, Nakase, Mihama-ku, Chiba-shi, Seiko Instruments Inc. (72) Inventor Osamu Yamazaki 1-8-8 Nakase, Mihama-ku, Chiba-shi, Chiba Seiko Instruments Inc. In-company (72) Inventor Chiari Pref. 1-8-8 Nakase, Mihama-ku, Chiba City, Chiba Prefecture Inside Seiko Instruments Inc. (72) Inventor Masafumi Hoshino 1-8-1, Nakase, Mihama-ku, Chiba City, Chiba Prefecture Inside Seiko Instruments Inc. (72) Inventor Shuhei Yamamoto Chiba 1-8 Nakase, Mihama-ku, Chiba-shi

Claims (9)

[Claims] 1. A front substrate and a rear substrate each having electrodes formed thereon, a liquid crystal layer sandwiched between the electrodes of the front substrate, the rear substrate and the electrodes, and a liquid crystal layer interposed between the rear substrate and the liquid crystal layer. A reflective color liquid crystal comprising: a reflective layer provided therebetween; and a transparent substrate on which a color filter is formed, wherein the front substrate and the transparent substrate are disposed so as to face each other via an air layer. Display device. 2. The reflection type color liquid crystal display device according to claim 1, further comprising an illuminating unit for receiving light from a side surface of the front substrate. 3. The reflection type color liquid crystal display device according to claim 1, wherein the liquid crystal layer is a polymer dispersed liquid crystal layer. 4. The reflection type color liquid crystal display device according to claim 1, wherein the reflection layer doubles as a counter electrode formed on the back substrate. 5. The reflective color liquid crystal display device according to claim 1, wherein the color filters are arranged in vertical stripes having the same color in the vertical direction of the display surface of the reflective color liquid crystal display device. . 6. The reflective color liquid crystal display device according to claim 1, wherein the transparent substrate also serves as a part of a component of a touch panel type input device. 7. The reflection type color liquid crystal display device according to claim 2, wherein said back substrate and said illuminating means are provided on the same circuit board. 8. The reflection type color liquid crystal display device according to claim 2, wherein said lighting means is provided on a holding member for holding the liquid crystal panel on a circuit board. 9. A predetermined distance between a front substrate on which the first electrode is formed and a rear substrate on which the second electrode and the reflective layer are formed so that the electrodes formed on the respective substrates face each other. And a step of injecting a liquid mixture of the liquid crystal and the polymer precursor into the gap between the substrates, a step of irradiating ultraviolet rays from outside the front substrate to phase-separate the liquid crystal and the polymer resin, and after the phase separation, A step of arranging a transparent substrate having a color filter and the front substrate with an air layer therebetween so as to face each other.