JP2002082352A - Liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display element having high reliability, at a low cost. SOLUTION: The liquid crystal display element is constructed, by laminating three liquid crystal display cells 50B, 50G, 50R reflecting or absorbing blue, green, red respectively. The liquid crystal cells 50B, 50G, 50R respectively consist of two sheets of substrates 11B, 12B; 11G, 12G; 11R, 12R having transparent electrodes 21B, 22B; 21G, 22G; 21R, 22R arranged thereon and holding liquid crystals 30B, 30G, 30R in-between. The between the cells are stuck with adhesive layers 71, 72. A background layer 41 is provided on the rear side of the cell 50R, placed at the lowermost layer of the liquid crystal display element, as seen from the observer's side. A gas barrier layer 81B is arranged on the observer's side surface of the cell 50B, and a gas barrier layer 81R is arranged on a surface of the cell 50R which lies opposite to the observer's side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display element used as a display panel or an image recording / display medium of electronic equipment, and more particularly to a liquid crystal display element formed by stacking liquid crystal display cells using a resin substrate. Things.

[0002]

2. Description of the Related Art A liquid crystal display device using a resin substrate is used for portable information equipment and the like because it is thin and lightweight and hard to break. As a method of multicoloring such a liquid crystal display element, a liquid crystal display element in which a plurality of liquid crystal display cells having different display colors are stacked is known. As the liquid crystal, a guest-host liquid crystal, a cholesteric liquid crystal having selective reflection in a visible wavelength range, a polymer-dispersed liquid crystal that is optically separated by using a hologram method, and the like are used. The liquid crystal display element has a method of stacking liquid crystal cells that absorb blue, green, and red color light, respectively, to achieve multicolor by subtractive color mixing, and a method of stacking liquid crystal cells, each of which reflects blue, green, and red, and adding and mixing them. There is a method to colorize. Here, blue, green, and red mean 400 to 500 nm, 500 to 600 nm, and 600, respectively.
It means colored light belonging to the wavelength band of ~ 700 nm.

A resin substrate has a higher moisture and oxygen permeability coefficient than a glass substrate. For this reason, in the resin substrate for a liquid crystal display element, in order to ensure reliability, it is preferable to provide the gas barrier layer 81 on one surface of the substrate 11 and the transparent electrode 21 on the other surface, as shown in FIG. General. As the gas barrier layer, a deposited film of an inorganic material such as SiO ₂ or a high gas barrier resin such as an ethylene-vinyl alcohol copolymer is used. FIG. 4 shows a liquid crystal display element for multicolor display using a resin substrate of this type. This liquid crystal display element has liquid crystal display cells 51B, 51B for blue, green, and red.
It is manufactured by bonding G and 51R with adhesive layers 71 and 72. Each of the liquid crystal display cells 51B, 51G, 51R is
On both surfaces of the liquid crystal 30, a resin substrate including the substrates 11, 12 gas barrier layers 81 and the transparent electrodes 21, 22 is provided, respectively, and the background layer 41 is formed on the opposite side of the liquid crystal display cell 51R from the adhesive layer 72 side.

[0004]

However, the above-mentioned gas barrier layer has low productivity and causes an increase in the manufacturing cost of the liquid crystal display device. In particular, in a multicolor liquid crystal display element in which a plurality of liquid crystal display cells are stacked, there is a problem in that the cost is high because six resin substrates each having such an expensive gas barrier layer are used.

Accordingly, an object of the present invention is to provide a low-cost and highly reliable liquid crystal display device.

[0006]

The above object has been achieved by a liquid crystal display device comprising a liquid crystal cell laminate formed by laminating a plurality of liquid crystal display cells, and a pair of gas barrier layers sandwiching the liquid crystal cell laminate. Is done. Here, a face plate can be provided on the side of the one gas barrier layer opposite to the liquid crystal cell stack side. Further, a light absorbing layer can be provided between the other gas barrier layer and the liquid crystal cell laminate. In this case, a metal foil can be used as the other gas barrier layer.

Further, a liquid crystal display device according to the present invention comprises a liquid crystal cell laminate formed by laminating a plurality of liquid crystal display cells, and a pair of liquid crystal cells laminated so as to sandwich all the liquid crystal layers in the liquid crystal cell laminate. And a gas barrier layer.

Further, the liquid crystal display element according to the present invention comprises a liquid crystal display cell in which liquid crystal is sealed between resin substrates each having a transparent electrode, and is provided on one side of the liquid crystal display cell. A gas barrier layer provided, a metal foil provided on the other side of the liquid crystal display cell, and a light absorbing layer provided between the metal foil and the liquid crystal display cell. Here, the metal foil has a function as a gas barrier layer. Further, the liquid crystal display cell may include a cholesteric liquid crystal, and in this case, the light absorption layer is used as a background layer.

With this configuration, the number of gas barrier layers can be reduced from six to two, and the cost can be reduced. Further, by providing the face plate on the gas barrier layer provided on the viewer's side surface of the liquid crystal display element, the vapor deposition film on the resin substrate becomes unnecessary, and the cost can be reduced.

Further, by using a metal foil, which is less expensive than a vapor-deposited film, as the gas barrier layer on the surface of the liquid crystal display element opposite to the viewer side, the cost can be further reduced. Also,
Since this metal foil has flexibility, it does not impair the impact resistance of the resin substrate, and because of its excellent thermal conductivity, heat conduction from the finger when holding the liquid crystal display element by hand or from peripheral circuits etc. This is effective in reducing display unevenness caused by temperature distribution due to heat conduction.

[0011]

FIG. 1 is a view showing one embodiment of a liquid crystal display device according to the present invention. The liquid crystal display element in the present embodiment has three liquid crystal display cells 50B, 50G, which reflect or absorb blue, green, and red.
50R are laminated. Liquid crystal cell 50B; 50
G; 50R are transparent electrodes 21B, 22B;
G, 22G; two substrates 11 provided with 21R, 22R
B, 12B; 11G, 12G; liquid crystals 30B, 30G, 30R are sandwiched between 11R, 12R, and the cells are bonded with adhesive layers 71, 72 between the cells. A background layer 41 is provided on the back surface side of the cell 50R located at the lowermost layer when viewed from the viewer side of the liquid crystal display element. The background layer 41 can be a light absorbing layer. Further, a gas barrier layer 81B is provided on the side of the observer of the cell 50B, and a gas barrier layer 81R is provided on the surface of the cell 50R opposite to the observer.

As the gas barrier layers 81B and 81R, S
a deposited film formed by depositing an inorganic material such as iO ₂ or SiNx by an evaporation method, a sputtering method, an ion plating method, or the like;
Alternatively, a light-transmitting gas barrier material such as a high gas barrier resin such as an ethylene-vinyl alcohol copolymer can be used. The gas barrier layers 81B and 81R correspond to the liquid crystal layers 30B, 30G, and 3 of the liquid crystal cells 50B, 50G, and 50R.
0R, for example, the gas barrier layer 81
B may be provided between the liquid crystal layer 30B and the substrate 11B.
Similarly, the gas barrier layer 81R is connected to the liquid crystal layer 30R and the substrate 12R.
And may be provided between them.

The display modes used in the liquid crystal display device include a guest-host mode, a mode using selective reflection and optical rotation dispersion of a cholesteric liquid crystal, a polymer dispersed liquid crystal mode manufactured using a hologram optical phase separation method, and a twisted nematic mode. Mode, super twisted nematic mode, surface stabilized ferroelectric liquid crystal mode, and the like. According to these display modes, cells 50B, 50B
A polarizing plate or a retardation plate may be added to G and 50R.

The liquid crystals 30B, 30G and 30R include liquid crystal compositions such as cyanobiphenyl, phenylcyclohexyl, phenylbenzoate, cyclohexylbenzoate, azomethine, azobenzene, pyrimidine, dioxane, cyclohexylcyclohexane, and tolane. Use things. As the liquid crystal phase, a nematic phase, a cholesteric phase, a smectic phase, a chiral smectic phase, or the like is used according to the display mode. If necessary, an additive such as a chiral agent or a dichroic dye may be added to the liquid crystal composition. Further, the liquid crystal composition may be dispersed in a polymer matrix, polymerized into a gel, or encapsulated. Also, polymer liquid crystal,
Either a medium molecular liquid crystal or a low molecular liquid crystal may be used, or a mixture thereof may be used.

Substrates 11B, 12B; 11G, 12G; 1
As 1R and 12R, translucent resins such as polycarbonate, polyethylene terephthalate, polyether sulfone, and polyolefin are used. These thicknesses are used in the range of several tens μm to several hundreds μ.

Transparent electrodes 21B, 22B; 21G, 22
G; 21R and 22R are ITO (Indium)
A light-transmitting conductive member such as a conductive oxide such as Tin Oxide, SnO ₂ , or ZnO: Al, or a conductive resin such as polypyrrole or polyaniline is used. These can be formed into a film by an evaporation method, a sputtering method, an ion plating method, a sol-gel method, a coating method, a printing method, an electrodeposition method, or the like. After the film formation, it may be processed into a desired shape by using a lithography method or the like.

The liquid crystals 30B, 30G, 30R and the transparent electrode 2
1B, 22B; 21G, 22G; 21R, 22R, a resin such as polyimide, an inorganic vapor-deposited film such as SiO,
A silane-based or ammonia-based surface modifier may be provided as an alignment film. The adhesive layers 71 and 72 have the function of fixing the relative positions of the cells, preventing the entry of air or moisture, and reducing the decrease in contrast caused by the reflection on the cell surface. As the adhesive layers 71 and 72, a light-transmitting substrate 11
B, 12B; 11G, 12G; It is preferable to use an adhesive or a pressure-sensitive adhesive having a refractive index close to that of 11R, 12R. As the material, a resin such as acryl, epoxy, urethane, or polyester can be used. As the curing mode of the adhesive, an ultraviolet curing type, a thermosetting type, a hot melt type or the like can be used.

In the case of a display mode that reflects blue, green and red, such as a selective reflection mode of cholesteric liquid crystal, the background layer 41 is used as a light absorbing layer that absorbs these reflected wavelength bands. The color tone can be appropriately selected in view of the display effect, but a black background is used for full-color display. Its materials include paints containing dyes and pigments,
Alternatively, a deposited film such as a metal or metal oxide film can be used. On the other hand, in the case of a display mode that reflects blue, green, and red, such as a guest host mode, the background layer 41 that reflects these reflection wavelength bands is used. The color tone can be appropriately selected in view of the display effect, but a white background is used for full-color display. As the material, a vapor-deposited film or foil of a high-reflectance metal such as aluminum or silver can be used. In this case, the background layer 41 can also serve as the adjacent gas barrier layer 81R. Cell 50B, 5
The stacking order of 0G and 50R need not be limited to this,
They can be stacked in any order.

<Embodiment 2> FIG. 2 is a view showing another embodiment of the liquid crystal display device according to the present invention. The liquid crystal display element in this embodiment is configured by stacking three liquid crystal display cells 50B, 50G, and 50R that reflect or absorb blue, green, and red. Liquid crystal cell 50B; 50G; 50R
Are transparent electrodes 21B and 22B; 21G and 22 respectively.
G; two substrates 11B and 12 provided with 21R and 22R
B: 11G, 12G; liquid crystal 30 between 11R, 12R
B, 30G, and 30R are sandwiched, and the cells are bonded with adhesive layers 71 and 72 between the cells. A background layer 41 is provided on the back surface of the cell 50R located at the lowermost layer when viewed from the viewer side of the liquid crystal display element. Then, a gas barrier layer 81B is provided on an observer side surface of the cell 50B via an adhesive layer 73, and a face plate 10 is provided on the gas barrier layer 81B. The background layer 41 on the opposite side of the cell 50R from the observer side.
Is provided with a gas barrier layer 81R made of metal foil. The background layer 41 can be a light absorbing layer.

The face plate 10 is made of a translucent resin such as acryl, methacryl, polycarbonate, polyethylene terephthalate, and polyester. The thickness can be used in the range of several tens μm to several mm. A hard coat is applied to the surface of the liquid crystal display element on the viewer side,
You may make it resistant to damage. Gas barrier layer 81B
The same as described in the first embodiment is used. The face plate 10 is adhered to the cell 50B by the adhesive layer 73 via the gas barrier layer 81B. The gas barrier layer 81R is made of a metal foil such as aluminum or copper. Its thickness can be used in the range of several μm to several hundred μm.

[0021]

According to the present invention, a low-cost and highly reliable liquid crystal display device can be provided.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of a liquid crystal display device according to the present invention.

FIG. 2 is a view showing another embodiment of the liquid crystal display device according to the present invention.

FIG. 3 is a cross-sectional view illustrating a general configuration example of a resin substrate.

FIG. 4 is a cross-sectional view illustrating a configuration example of a conventional liquid crystal display element.

[Explanation of symbols]

Reference Signs List 10 face plate 11B, 11G, 11R, 12B, 12G, 12R substrate 21B, 21G, 21R, 22B, 22G, 22R transparent electrode 30B, 30G, 30R liquid crystal 41 background layer 50B, 50G, 50R liquid crystal display cell 71, 72, 73 Adhesive layer 81B, 81R Gas barrier layer

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Taketo Hikiji 2274 Hongo, Ebina-shi, Kanagawa Fuji Xerox Co., Ltd. In-house F-term (reference) 2H089 HA23 HA32 QA16 RA04 RA06 RA11 RA13 TA01 TA13 TA17 2H090 JB03 JD01 JD11 KA04 KA06 KA09 KA11 KA12 KA14 LA05 LA20 5C094 AA31 AA37 AA38 BA07 BA12 BA43 CA19 CA04 DA03 A13 EA13 EA13 EA13 EA12 CC12 EE33 FF14 GG01 GG42 HH12 HH14

Claims (7)

[Claims] 1. A liquid crystal display device comprising: a liquid crystal cell stack formed by stacking a plurality of liquid crystal display cells; and a pair of gas barrier layers sandwiching the liquid crystal cell stack. 2. The liquid crystal display device according to claim 1, wherein a face plate is provided on one of the gas barrier layers on the side opposite to the liquid crystal cell laminate side. 3. The liquid crystal display device according to claim 1, further comprising a light absorbing layer between the other gas barrier layer and the liquid crystal cell laminate. 4. The liquid crystal display device according to claim 3, wherein the other gas barrier layer is made of a metal foil. 5. A liquid crystal cell laminate comprising a plurality of liquid crystal display cells laminated, and a pair of gas barrier layers laminated so as to sandwich all liquid crystal layers in the liquid crystal cell laminate. Characteristic liquid crystal display element. 6. A liquid crystal display element comprising a liquid crystal display cell in which liquid crystal is sealed between resin substrates each having a transparent electrode, wherein a gas barrier layer provided on one side of the liquid crystal display cell is provided. A liquid crystal display device comprising: a metal foil provided on the other side of a liquid crystal display cell; and a light absorbing layer provided between the metal foil and the liquid crystal display cell. 7. The liquid crystal display device according to claim 1, wherein the liquid crystal display cell includes a cholesteric liquid crystal.