Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
2002-12-13
2003-07-29
Ngo, Julie (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S104000, C430S007000, C430S311000, C430S321000
Reexamination Certificate
active
06600533
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid crystal display device capable of providing bright display without using a polarizing plate, and more particularly to a liquid crystal display device capable of providing desired display by contrast between a color filter film applied to a substrate and a liquid crystal material doped with dichroic dyes.
2. Description of the Related Art
The liquid crystal display device has such a structure as seen from the general structure of a transmission type liquid crystal display panel shown in FIG.
8
. Specifically, as seen from
FIG. 8
, electrode patterns
3
and
4
are formed on the surfaces of insulating substrates
1
and
2
, and orienting films
5
and
6
are formed thereon. The two insulating substrates
1
and
2
are bonded to each other on their peripheries by a sealant
7
with a prescribed gap of a spacer (not shown) therebetween. The liquid crystal is injected into the gap to constitute a liquid crystal layer
8
. On the outsides of the insulating substrates
1
and
2
, polarizing plates
9
and
10
are provided. In this way, a liquid crystal display panel
11
is formed.
On the rear side of the liquid crystal panel
11
which is opposite to a viewer, a back light
13
such as a bulb, a fluorescent etc. is arranged through an optical diffusing plate
12
. With respect to the light from the back light
13
, only linear polarized light of natural light in a certain vibrating direction can be transmitted by means of the polarizing plate
9
on the rear side. According to whether or not a voltage is applied to the liquid crystal layer, the light travels with the vibrating direction twisted or travels straight as it is with the vibration direction not twisted. Whether or not the light is transmitted can be controlled by the absorption axis of the polarizing plate
10
on the front side which is a viewer side to provide a desired display.
As described above, the conventional liquid crystal display device uses the polarizing plates to adopt only the light vibrating in a certain direction of natural light. Therefore, most of the light is interrupted by the polarizing plate so that unless a bright back-light is used, bright display cannot be realized. However, use of the bright back-light excessively consumes a battery in a liquid crystal display device such as a portable appliance which is driven by the battery. This applies to a reflection type liquid crystal display device in which light is caused to be incident from the viewer side to use the reflected light. Namely, in the reflection type liquid crystal display device, a bright image can be obtained only in a bright place.
In addition, the polarizing plate is very expensive to increase the production cost of the liquid crystal display device. This provides a limit of cost reduction in the LC device which is used in an inexpensive electronic appliance such as a portable appliance. The present invention has been accomplished in order to solve such a problem.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a liquid crystal display device capable of providing bright display without using polarizing plates and can be manufactured at low cost.
In order to attain the above object, in accordance with a first aspect of the present invention, there is provided a liquid crystal display device comprising: first and second substrates with electrode patterns formed thereon on a front side and rear side of the device, which are bonded to each other on their peripheries by a sealant with a prescribed gap therebetween; a liquid crystal material doped with dichroic dyes injected into the gap to constitute a liquid crystal layer; a first color filter film with a prescribed color provided at an area where the electrode pattern is not provided on the first substrate on the front side; and a second color filter film with the same color as the prescribed color at at least an area where the electrode pattern is not provided on the second substrate on the rear side.
In the present invention, the first substrate on the front side refers to a substrate on the side of a viewer when he sees the liquid crystal display device. The second substrate on the rear side refers to another substrate on the side (background) far from the viewer. Further, the color filter film with a prescribed color refers to a color filter of the background of the liquid crystal display device, which may provide a whitish background such as transmitted white light by printing e.g. white ink and yellow ink. The color filter film may be provided not on the side of the liquid crystal layer of the substrate, but may be provided on the side opposite to the liquid crystal layer.
In the above configuration, an area where the electrode pattern is not provided on the first substrate on the front side is viewed as the color, e.g. white of the color filter on the front side. As for the area where the electrode pattern is provided on the first substrate on the front side, the portion with a voltage applied between itself and an opposite electrode, where liquid crystal molecules rise, appears as the color of the color filter applied to the surface of the electrode pattern on the second substrate on the rear side. The portion with a voltage not applied between itself and an opposite electrode appears as the color (e.g. black) of the dichroic dyes added to the liquid crystal. Thus, by controlling the application of a voltage, a desired display in e.g. black can be made on a white background.
In accordance with the present invention, a desired display can be realized by voltage control without using a polarizing plate so that a very bright display screen can be obtained. Therefore, the liquid crystal display device according to the present invention can be applied to a transmission type liquid crystal display device such as a portable appliance or a reflection type liquid crystal display device which can be used in a dim place. The present invention, in which no polarizing plate is used, can be realized at low cost, thus contributing the cost reduction of an electronic appliance using the liquid crystal display device.
A second aspect of the device is a liquid crystal display device according to the first aspect, wherein said first substrate comprises a light-permeable substrate; a light-permeable electrode pattern formed on an internal surface of said light-permeable substrate so as to correspond to a light emitting segment; a first color filter film formed at an area where the light-permeable electrode pattern is not provided; and an orienting film formed to cover the entire surface of the first substrate.
A third aspect of the device is a liquid crystal display device according to the first aspect, wherein said second substrate comprises a substrate, an electrode pattern formed on an internal surface of said substrate so as to correspond to a light emitting segment, a second color filter film with the same color as the prescribed color stacked on the electrode pattern so as to have the same pattern as that of the electrode pattern, and an orienting film formed to cover the entire surface of the second substrate.
A fourth aspect of the device is a liquid crystal display device according to the first aspect, wherein said first substrate comprises a light-permeable electrode pattern formed on an internal surface of a light-permeable substrate so as to correspond to a light emitting segment; an orienting film formed thereon and a first color filter film on an outer surface of said light-permeable substrate formed at an area where the light-permeable electrode pattern is not provided; and an orienting film formed to cover entirety of the first substrate.
A fifth aspect of the device is a liquid crystal display device according to the first aspect, wherein said second substrate comprises a substrate; an electrode pattern formed on an internal surface of said substrate so as to correspond to a light emitting segment; an orienting film formed thereon; and a second color filt
Ngo Julie
Rohm & Co., Ltd.
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