JPH0411224A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To display many pieces of information on a still or moving picture, etc., by driving plural pixel electrodes independently by a driving means for which they are connected by lead wires. CONSTITUTION:This device is provided with an insulating substrate 1, the plural pixel electrodes 2 provided on the insulating substrate 1, a liquid crystal layer 4 formed on the insulating substrate 1, a common transparent electrode 3 formed on the liquid crystal layer 4, and the driving means 6 which drives the pixel electrodes 2 independently of one another. Then the liquid crystal layer 4 is formed of a liquid crystal material incorporated in a capsule and the plural pixel electrodes 2 are connected to the driving means 6 by the lead wires 5 penetrating into the insulating substrate 1. Consequently, only the arraying state of the liquid crystal included in the liquid crystal material at a part corresponding to a selected pixel electrode 2 is changed to obtain brightness with a contrast which is high enough for distinction from peripheral picture elements. Consequently, many pieces of information on the still or moving picture can be displayed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device using encapsulated liquid crystal material.

[Prior Art] Conventionally, liquid crystal materials encapsulated in capsules have been known.
Display devices using the above materials are also known. Regarding the above liquid crystal materials and display devices using them,
-501631 and J.L. Ferguson, [Polymer Encapsulated Nematic Liquid Crystals for Displays and Light Control Devices (
”Polymer EncapsulatedNema
tic Crystals for Display
and Light Control Applic
SID International Symposium Digest of Technical Papers (SID International Symposium Digest of Technical Papers)
Posium Digest of Technica
1 Papers), p. 68-70 (1985)).

FIG. 2 is a cross-sectional view showing the structure of the liquid crystal display device described in the above-mentioned document using a liquid crystal material contained in a capsule. In FIG. 2, the liquid crystal material 21 contained in the capsule is
A liquid crystal layer 24 is formed between a transparent front substrate 22 and a rear substrate 23. On the surfaces of the front substrate 22 and the rear substrate 23 on the liquid crystal layer 24 side, there are transparent electrodes 2 facing each other.
5 and 26 are provided. FIG. 3 is a sectional view showing the structure of the liquid crystal material described in the above publication. The liquid crystal material 21 has nematic phase liquid crystal molecules 31 encapsulated in capsules 32 of a polymer such as polyvinyl alcohol having the same refractive index as the refractive index of the liquid crystal molecules when they are aligned;
The liquid crystal molecules 31 in the capsule exist in a distorted manner along the inner wall 32a of the capsule when no voltage is applied, and the liquid crystal molecules 31 are considered to be in an unoriented state in the liquid crystal layer 24 as a whole.

Therefore, the apparatus of FIG. 2 operates as follows.

First, when no voltage is applied, the incident light is scattered by the liquid crystal molecules contained in the capsule and the polymer constituting the capsule, so a cloudy state of the liquid crystal layer 24 is observed through the transparent front substrate 22. Ru. At this time, the incident light does not pass through the liquid crystal layer 24. Furthermore, by having a biaxial black dye exist together with liquid crystal molecules in the capsule, incident light can be absorbed by the dye and blocked.

On the other hand, when a voltage is applied to the device shown in FIG. 2, the liquid crystal molecules 31 contained in the capsule 32 are aligned parallel to the direction of the electric field, and the refractive index of the polymer forming the capsule and the liquid crystal are the same. Therefore, the incident light passes through the liquid crystal layer 24, and the state of the rear substrate 23 is observed through the transparent front substrate 22. At this time, the back substrate 23 does not necessarily have to be transparent; for example, if the back substrate 23 is colored,
Its coloration is observed.

Therefore, in the liquid crystal display device described above, display can be performed using nematic phase liquid crystal without using a polarizing element, and high brightness and high contrast can be obtained. Moreover, since the liquid crystal material is contained in a capsule, it is stable and reliable in the environment, and the polymer forming the capsule also acts as an adhesive, so just by applying the liquid crystal material to a substrate, it is possible to It is said that such a large display device can be easily realized.

[Problems to be Solved by the Invention] However, the liquid crystal material contained in the capsule has a gentle threshold characteristic and the alignment state of the liquid crystal molecules is only slightly non-linear with respect to the applied voltage. When a simple matrix display is performed, there is a problem in that the brightness changes continuously from a selected pixel to surrounding pixels due to voltage convergence, making it impossible to provide a clear display. For this reason, the conventional display devices described above have difficulty in time-division driving of matrix display, and are only applicable to displaying preset patterns using a limited number of segments, such as displaying numbers using Japanese-shaped segments. It has not been.

Therefore, the present invention has been made to solve the above problems of the prior art, and its object is to provide a liquid crystal display device using a liquid crystal material contained in a capsule, which simply displays a preset pattern. The object of the present invention is to provide a liquid crystal display device that can display not only still images but also more information such as moving images.

[Means for Solving the Problems] A liquid crystal display device according to the present invention includes an insulating substrate, a plurality of pixel electrodes provided on the insulating substrate, a liquid crystal layer provided on the insulating substrate, The liquid crystal layer includes a common transparent electrode provided on the liquid crystal layer and a driving means for independently driving each of the plurality of pixel electrodes, the liquid crystal layer is formed from a liquid crystal material contained in a capsule, and the plurality of pixel electrodes Each of the pixel electrodes is connected to the driving means by a lead wire passing through the insulating substrate.

Another liquid crystal display device according to the present invention includes a light source, a first insulating transparent substrate provided in front of the light source,
A first transparent electrode provided in a stripe pattern on the first insulating transparent substrate, a first liquid crystal layer provided on the first insulating transparent substrate, and a first liquid crystal layer provided on the first insulating transparent substrate. a common electrode provided on the common electrode, a second liquid crystal layer provided on the common electrode, a second insulating transparent substrate provided on the liquid crystal layer, and a second insulating transparent substrate provided on the second insulating transparent substrate. and a second transparent electrode provided in a stripe pattern perpendicular to the first transparent electrode on the surface of the liquid crystal layer side,
It is characterized in that the first and second liquid crystal layers are formed from a liquid crystal material encapsulated.

[Function] In the liquid crystal display device of the present invention, the plurality of pixel electrodes provided on the insulating substrate are each independently driven by driving means connected by lead wires. Therefore, only the alignment state of the liquid crystal contained in the liquid crystal material in the portion corresponding to the selected pixel electrode changes without causing any voltage leakage from the selected pixel to the surrounding pixels. As a result, only the selected pixel has high contrast brightness that can be distinguished from surrounding pixels.

Therefore, according to the liquid crystal display device of the present invention, it is possible to perform a clear display for each of a large number of pixels independently of other pixels, and it is possible to display a large amount of information such as still images and moving images. .

Further, in another liquid crystal display device of the present invention, a common transparent electrode is further disposed between two sets of transparent electrodes provided in a stripe shape orthogonal to each other on opposing substrates, and each of the stripe-shaped transparent electrodes A liquid crystal layer is provided between the common transparent electrode and the common transparent electrode. Each striped transparent electrode is driven independently, and voltage is applied to each liquid crystal layer between each striped transparent electrode and the common electrode. Therefore, it is possible to prevent voltages from running around between the striped transparent electrodes. In the liquid crystal display device, rows and columns through which light can pass through each liquid crystal layer are formed by a voltage applied between each striped transparent electrode and the common electrode, and the intersections between the rows and columns are formed. Matrix display can be performed by taking advantage of the fact that light passes through only those areas.

[Embodiments] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

Figure 1 is a sectional view showing an embodiment of a liquid crystal display device according to the present invention.

The liquid crystal display device of this embodiment is a reflective liquid crystal display device, and as shown in FIG. 1, a plurality of pixel electrodes 2 are provided on an insulating substrate 1, and a common transparent A liquid crystal layer 4 is provided between the electrode 3 and the electrode 3 .

In the liquid crystal display device, the liquid crystal layer 4 is made of a liquid crystal material in which nematic phase liquid crystal molecules are encapsulated in a capsule of a polymer such as polyvinyl alcohol, and the polymer forming the capsule has a refractive index of The refractive index is chosen to be the same as when the liquid crystal molecules are aligned parallel to the electric field. Preferably, the liquid crystal material contains a biaxial black dye together with liquid crystal molecules in the capsule. The black dye has the function of absorbing incident light and blocking light when no voltage is applied.

The thickness of the liquid crystal layer 4 is usually in the range of 20 to 30 μm. In the liquid crystal material mentioned above, since the polymer forming the capsule functions as an adhesive, the liquid crystal layer 4 can be formed simply by coating it on the insulating substrate 1, and a sealant is not required to seal the liquid crystal. I don't.

The common transparent electrode 3 may be formed on the surface of a transparent substrate such as glass or a self-supporting transparent film.

The pixel electrode 2 penetrates the insulating substrate 1 and
It is connected to a driving means 6 by a lead wire 5 taken out from the back side of the holder. Since the liquid crystal display device of this embodiment is a reflective liquid crystal display device, the driving means 6 can be provided on the back surface of the insulating substrate 1 (the side opposite to the side on which the liquid crystal layer 4 is provided), and This is advantageous because it can be connected to the lead wire 5.

The driving means 6 outputs a signal corresponding one-to-one to each pixel electrode 2, and the pixel electrodes 2 are driven independently. As a result, a predetermined voltage is applied between the driven pixel electrode and the common transparent electrode, and only the alignment state of the liquid crystal contained in the liquid crystal material in the portion to which the voltage is applied changes, causing light to pass through. You will be in a state where you can get it.

By outputting drive signals individually to each pixel electrode as described above, it is possible to apply a voltage only between the selected pixel electrode and the common transparent electrode facing the pixel electrode. Therefore, it is possible to substantially eliminate the influence of voltage leakage from the selected pixel electrode to the surrounding pixel electrodes. Therefore, high contrast brightness that can be distinguished from the surroundings is obtained only in the selected pixel, and clear display can be performed.

As the driving means, for example, a MOS-IC can be used, and it can be connected to 400 to 500 pixel electrodes. Using the above IC, by sequentially inputting 16 gradation inputs to each pixel electrode and repeating the latch output, all the pixel electrodes connected to the IC can be
It can be driven in about 30 seconds and can display still images or moving images.

In the liquid crystal display device of this embodiment, 400 to 500 pixels driven by one of the above-mentioned ICs constitute one unit, and a larger panel can be constructed by assembling a plurality of units in a mosaic pattern. . As mentioned above, in the liquid crystal display device, the polymer forming the capsule containing the liquid crystal molecules also acts as an adhesive.
The edges of each unit are hardened with the polymer. Advantageously, therefore, the edges do not require any special treatment and are not visible from the front.

Further, in the liquid crystal display device of this embodiment, color display can be performed by painting the surface of the pixel electrode 2 in red, blue, and green according to a predetermined pattern and driving as described above.

The liquid crystal display device of this embodiment is particularly advantageous when configuring a relatively large panel with no limit to the number of units per fixed area.

Toru Inuse I FIG. 4 is a sectional view showing an embodiment of a liquid crystal display device according to the present invention.

The liquid crystal display device of this embodiment is a transmission type liquid crystal display device, and as shown in FIG. 4, two glass substrates 42 and 43 are provided with a common transparent electrode 41 in between. A first liquid crystal layer 44 is provided between the glass substrate 42 and a second liquid crystal layer 45 is provided between the common transparent electrode 41 and the glass substrate 43. The glass substrate 42 is provided with first transparent electrodes 46 in the form of a stripe, and a liquid crystal layer 46 on the glass substrate 43 is provided.
On the 5-side surface, a second transparent electrode 47 is provided in a stripe shape orthogonal to the first transparent electrode 46 . A light source 48 is provided behind the glass substrate 42.

In the above liquid crystal display device, the liquid crystal layers 44 and 46 are made of the same liquid crystal material used in Example 1, in which nematic phase liquid crystal molecules are encapsulated in polymer capsules such as polyvinyl alcohol.

The common transparent electrode 41 is connected to the glass substrate 42 or 4.
For example, when it is formed on the surface of a transparent substrate such as glass or a self-supporting transparent film, which is formed in a planar shape facing 3, it is formed on the entire front and back surfaces thereof.

In the liquid crystal display device described above, the transparent electrodes 46 and 47 are each driven independently, and the voltage applied between the first transparent electrode 46 and the common transparent electrode 41 causes the first liquid crystal layer 44 and the second The voltage applied between the transparent electrode 47 and the common transparent electrode 41 forms portions in the second liquid crystal layer 45 that can transmit light. As mentioned above, the common transparent electrode 41 is arranged between the transparent electrodes 46 and 47,
between the first transparent electrode 46 and the common transparent electrode 41, and
By applying voltages separately between the second transparent electrode 47 and the common transparent electrode 41, it is possible to reduce the spread of voltage.

The liquid crystal display device performs matrix display by combining column display by the first liquid crystal layer 44 and row display by the second liquid crystal layer 46, which are each formed separately. FIG. 5 is a diagram for explaining the operation of the liquid crystal display device.

In the liquid crystal display device described above, first, light emitted from the light source 48 enters the first liquid crystal layer 44 . The first liquid crystal layer 4
4, a voltage applied between a selected one of the first transparent electrodes 46 and the common transparent electrode 41 causes the liquid crystal included in the liquid crystal material in the portion to which the voltage is applied to be parallel to the electric field. are aligned to form a portion 51 in the liquid crystal layer 44 through which light can pass. Since the first transparent electrodes 46 are provided in a striped pattern, the light-transmissible portions 51 are formed in rows parallel to selected ones of the first transparent electrodes. ing.

Therefore, the light incident on the first liquid crystal layer 44 is transmitted only through the light-transmissible portion 51, and is scattered in other portions of the liquid crystal layer 44, and furthermore, the liquid crystal material is biaxially contained. It is absorbed and blocked by black dye.

Next, the light-transmissible portion 5 of the first liquid crystal layer 44 is
The light that has passed through the liquid crystal layer 1 enters the second liquid crystal layer 45 . In the second liquid crystal layer 45, the voltage applied between the selected one of the second transparent electrodes 47 and the common transparent electrode 41 causes the liquid crystal material to be included in the portion to which the voltage is applied. The liquid crystals are arranged parallel to the electric field, forming a portion 52 in the liquid crystal layer 45 through which light can pass. Since the second transparent electrode 47 is provided in a stripe shape perpendicular to the first transparent electrode 46, the light-transmissible portion 52
is parallel to a selected one of the second transparent electrodes 47 and perpendicular to the first transparent electrode 46, that is, a light-transmissible portion 51 formed in the first liquid crystal layer. are formed in rows whereas they are formed in columns. Therefore, among the light that has passed through the light-transmissible portion 51 of the first liquid crystal layer 44 and entered the second liquid crystal layer 45,
Only the light (L,) incident on the overlapping portion 52a of the light-transmissible portions 51 and 52 passes through the second liquid crystal layer 4.
5 and is observed through the glass substrate 43.

Of the light that passes through the light-transmissible portion 51 of the first liquid crystal layer 44 and enters the second liquid crystal layer 45, a light-transmissible portion 52 of the second liquid crystal layer 45 is formed. Light (L,) incident on the non-containing portions is scattered, absorbed by the biaxial black dye contained in the liquid crystal material, and blocked. Furthermore, a portion 51 of the light-transmissible portion 51 of the first liquid crystal layer among the light-transmissible portion 52 of the second liquid crystal layer 45
Although the portion 52b that does not overlap has the function of transmitting light, no light enters the portion 52b, so nothing is observed from the front surface of the glass substrate 43.

Therefore, in the liquid crystal display device of this embodiment, the first liquid crystal layer 4
4, a row of portions 51 that can transmit light, and a first liquid crystal layer 45
The portion where the light-transmitting portion 52 overlaps with the row becomes a display portion (pixel), and a matrix display can be performed.

In Fig. 5, for simplicity, an example is shown in which one pixel is displayed by selecting one electrode at a time, but multiple electrodes forming each column and row are selected to display multiple pixels. Of course, it may be displayed.

In the liquid crystal display device of this embodiment, when the display surface is vertical, the number of electrodes forming vertical stripes is usually approximately 320, and the number of electrodes forming horizontal stripes is 8 to 1.
Six pieces is appropriate. If the number of horizontal stripe electrodes is larger than the above, the amount of light transmitted is the reciprocal of the number of electrodes, so the brightness tends to decrease.
It is desirable that the display that has been cycled around 30 times should not flicker.

The liquid crystal display device of this embodiment further allows the display of dots (pixels).
When configuring a large number of panels, for example a 400 x 640 dot display panel, the above liquid crystal display device may be arranged vertically in two
It can be configured by arranging 0 sheets and 2 sheets horizontally, a total of 50 sheets. When a plurality of liquid crystal display devices are arranged as described above, ICs for independently driving the transparent electrodes 46 or 47 are arranged on the side surfaces of the liquid crystal display devices (planes parallel to the light transmission direction). This prevents the display from becoming a hindrance.

The liquid crystal display device of this embodiment can also perform color display by providing red, blue, and green color filters in a mosaic or stripe pattern on the glass substrate 43. When performing color display, it is preferable to further increase the number of electrodes forming the vertical stripes.

[Effects of the Invention] According to the liquid crystal display device of the present invention, a plurality of pixel electrodes are driven individually, so that only between a pixel electrode selected substantially independently of other pixel electrodes and a common electrode. A voltage can be applied to.

Further, according to another liquid crystal display device of the present invention, a common transparent electrode is further arranged between two sets of transparent electrodes provided in a stripe shape orthogonal to each other on opposing substrates. Rows and columns that can avoid voltage circulation between the striped transparent electrodes and allow light to pass through formed in each liquid crystal layer provided between each of the striped transparent electrodes and the common electrode. It is possible to perform matrix display in which pixels are the intersections with the .

Therefore, according to any one of the above liquid crystal display devices of the present invention, a static More information such as images or videos can be displayed clearly.

Further, according to any one of the liquid crystal display devices of the present invention,
It is also possible to perform display with different shades of light and shade, such as 16-gradation display, or color display.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the structure of an embodiment of a liquid crystal display device according to the present invention, FIG. 2 is a sectional view showing the structure of a conventional example, and FIG. 3 is a sectional view showing the structure of a liquid crystal material contained in a capsule. 4 is a sectional view showing the structure of another embodiment of the liquid crystal display device according to the present invention, and FIG. 5 is an explanatory diagram of the operation of another embodiment. 1...Insulating substrate, 2...Pixel electrode, 3.
... common transparent electrode, 4 ... liquid crystal layer, 5 ... lead wire, 6 ... driving means (IC), 41 ...
- Common transparent electrode, 42.43...Glass substrate, 44...First liquid crystal layer, 45...Second liquid crystal layer, 46...First transparent electrode, 47...Second transparent electrode, 48...light source.

Claims (2)

[Claims] (1) an insulating substrate; a plurality of pixel electrodes provided on the insulating substrate; a liquid crystal layer provided on the insulating substrate; a common transparent electrode provided on the liquid crystal layer; a driving means for independently driving a plurality of pixel electrodes, wherein the liquid crystal layer is formed from a liquid crystal material contained in a capsule, and the plurality of pixel electrodes are connected to each other by lead wires penetrating the insulating substrate. A liquid crystal display device, characterized in that it is connected to a driving means. (2) a light source; a first insulating transparent substrate provided in front of the light source; a first transparent electrode provided in a stripe pattern on the first insulating transparent substrate; a first liquid crystal layer provided on the insulating transparent substrate; a common electrode provided on the first liquid crystal layer; a second liquid crystal layer provided on the common electrode; and a second liquid crystal layer provided on the common electrode. a second insulating transparent substrate provided on the second insulating transparent substrate; and a second insulating transparent substrate provided in a stripe pattern perpendicular to the first transparent electrode on the surface of the second insulating transparent substrate facing the liquid crystal layer. 1. A liquid crystal display device comprising two transparent electrodes, wherein the first and second liquid crystal layers are formed from a liquid crystal material encapsulated in a capsule.