JPS60247618A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To obtain a display device with no parallax by reducing the thickness of glass substrates to a specified value or below. CONSTITUTION:A liq. crystal display element having glass sheets of 0.2mm. thickness as glass substrates 1 makes a full color display by using a twist nematic liq. crystal layer 3 as a transmission negative layer and utilizing the shutter effect of a display image element. The effective thickness (t) of the glass substrates is <=0.2mm., and the display element can make a clear color display with little shear n color. THe parallax is reduced, reliability comparable to that of a monochromatic liq. crystal display element is attained, and it is not required to increase the driving voltage. A layer of coloring matter is separated from the liq. crystal layer, transparent electrode films and orienting films, so little physical or chemical restrictions are placed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a liquid crystal display device in which an electrode substrate is made of glass, plastic film, or the like. At least one glass substrate is made thinner, thereby providing a clear display with a wide viewing angle. [Technical background] Particularly regarding the structure of a liquid crystal display device related to color display [Technical background] Conventionally, birefringence control method, guest-host method, twisted nematic method, and cholesteric method have been studied for colorizing liquid crystal display elements.

In the twisted nematic method, color display using a dye layer is the mainstream. As the dye layer, a color filter, a color polarizer, etc. are used. Conventionally, two methods have been devised for forming a dye layer in a liquid crystal cell.

Method of forming a dye layer outside the liquid crystal cell Method of forming a dye layer inside the liquid crystal cell Figure 6 shows the structure of a transmissive liquid crystal color display element created by the method of forming a dye layer outside the liquid crystal cell. .

A liquid crystal cell consists of a glass substrate 1, a spacer 2. The basic structure is a liquid crystal layer 3, and a polarizer 4 is provided on the observation side. On the light source side, there is a color filter 5. Polarizers 4 are sequentially stacked. The color filter is displayed by turning on and off the liquid crystal layer.4-1 za< J-/L C1+-s
n −/ −ys m + 7 J−1−y +, 7
. If the color filter has a stripe pattern or a mosaic pattern consisting of five colors of red, green, and blue, full color display is possible. However, with this structure, when the display is observed from an oblique direction, color misalignment occurs between the display portion and the corresponding portion of the filter. As shown in FIG. 7, in a liquid crystal display element using a glass material with a thickness of t as a glass substrate, when observed from an angle θ with respect to the normal direction of the liquid crystal cell (ignoring the refractive index of the constituent materials), The part of the filter visible in the same position as the display pixels in the liquid crystal layer is
In terms of implementation, there is a parallax of ΔX between the display pixel A and the corresponding pixel B of the filter layer.

Δx=:t--〇 (1) With this display element, the color of pixels adjacent to pixel B in the filter layer is visible. (Color shift) As a result, accurate color display cannot be performed. Therefore, it is unclear and the observation direction is limited.
It had drawbacks such as narrow viewing angle.

FIG. 8(α), Cb) shows the structure of a transmissive liquid crystal color display element produced by a method of forming a dye layer outside the liquid crystal cell.

In FIG. 8(α), a dye layer 11 is formed on the transparent electrode film 9, and an alignment film is provided. This structure can be created using several methods called electrode coloring methods. In this structure,
Since there is no separation between the liquid crystal layer 3 and the dye layer 11, color display without color shift is possible. However, since foreign matter is introduced into the liquid crystal cell, the reliability of the liquid crystal display element decreases due to interaction between the liquid crystal material and the dye.

B. The adhesion strength between the electrode film, alignment film, and dye is important.

First, since the dye layer acts as an insulator between the electrode film and the liquid crystal layer, normal display cannot be obtained unless the driving voltage is increased.

Engineering and manufacturing are complicated and expensive.

There were drawbacks such as. FIG. 8Cb) is an improved structure of FIG. 8(α). In this method, a dye layer 11 is directly formed on a glass substrate 1, and a transparent electrode film 9 and an alignment film 10 are arranged thereon. Although these two structural defects have been resolved, the technical disadvantages A, B, and Engineering have not been resolved.

[Object of the present invention]

The present invention overcomes these drawbacks of conventional methods. The basic structure is based on a method of forming a dye layer outside the liquid crystal cell.

(In the formula, the parallax ΔX is affected only by the thickness t of the glass substrate, and in order to reduce the parallax ΔX,
It is sufficient to reduce the thickness t of the glass substrate.

[Example 1] FIG. 1 shows an example of the present invention. A glass material having a thickness of 0.2 wm is used as the glass substrate 1.

This liquid crystal display element uses a twisted nematic type liquid crystal layer 3 as a transparent negative type, and uses the shutter effect of display pixels to display full color. Note that the ↑ mark indicates the light source. The thickness t of the glass substrate is 0.2
11II or less is effective and allows clear color display with less color shift. Further, according to the present invention, it is possible to obtain reliability equivalent to that of monochrome display liquid crystal display elements, which are already in practical use, with less power and parallax.

Therefore, there is no need to increase the driving voltage.

Since the dye layer is isolated from the liquid crystal material, the transparent electrode film, and the alignment film, there are few physical and chemical restrictions, so there is a high degree of freedom in selecting the dye.

It is easy to manufacture and inexpensive.

There are other effects. This liquid crystal display element is driven by a circuit shown in FIG. 2 (α). FIG. 2Cb) is a driving waveform.

[Example 2] FIG. 3 shows the structure of a transmission type liquid crystal color display element. In this example, a color polarizer 6 was used instead of the color filter 5 of Example 1.

[Example 3] In this example, the present invention is applied to a monochrome reflective liquid crystal display element. Figure 4 shows its structure. A polarizer 49 and a reflective plate 7 are sequentially deposited on a glass substrate 1, and because the distance between the liquid crystal layer and the reflective surface is short, there is no shadow (ghost due to parallax) and clear display is possible.

A wide viewing angle can be obtained.

There are other effects. Note that the display may be in a segment format, a character format, or a dot matrix format.

[Example 4] In this example, the present invention is applied to a guest-host type liquid crystal display element. Figure 5 shows its structure. The liquid crystal layer 8 is made of a twisted nematic liquid crystal material with a dichroic dye added thereto to make it negative, and utilizes the shutter effect of display pixels. , performs pull color display.

〔effect〕

Since the liquid crystal display device of the present invention is configured as described above, it is possible to configure a display device without parallax.

[Brief explanation of drawings]

FIG. 1 shows the structure of a transmissive liquid crystal color display element according to Example 1 of the present invention. FIG. 2 is an explanatory diagram of driving the liquid crystal display device of the present invention.
Figure (cL) shows the circuit, and Figure 2 (b) shows the driving waveform. FIG. 3 shows the structure of a transmissive liquid crystal color display element according to Example 2 of the present invention. FIG. 4 shows the structure of a reflective liquid crystal monochrome display element according to Example 3 of the present invention. FIG. 5 shows the structure of a guest-host type liquid crystal color display device according to Example 4 of the present invention. FIG. 6 shows the structure of a transmissive liquid crystal color display element produced by a method of forming a dye layer outside the liquid crystal cell. FIG. 7 shows the parallax of the liquid crystal display element shown in FIG. 6. FIGS. 8(Z) and 8(b) each show the structure of a transmissive liquid crystal color display element produced by a method of forming a dye layer inside a liquid crystal cell. 1...Glass substrate 2...Spacer 3...Liquid crystal layer 4...Polarizer 5...・・・・・・Color filter 6・・・・・・
...Color polarizer 7...Reflector plate 8...Guest-host type liquid crystal layer 9...
......Transparent electrode film 10...Alignment film 11...Dye layer 12...X drive circuit 13...Y drive circuit 14... ... Display memory circuit 15 ... Timing generation circuit θ ... Viewing direction t ... Thickness ΔX of glass substrate 1 ...
・・Pallax A・・・Display pixel B of liquid crystal layer・・・・・・・
... Pixel of pigment layer Fig. 1 g3 (C1) (b) Fig. 2 Fig. 4 θ 'j15WA Fig. 6 Fig. 7 Fig. 4 (b) Fig. 8 Procedural amendment (voluntary) Show fI] 59 Patent Application No. 105525, dated 847/1984, 2, Name of the invention, Liquid crystal display device 3, Relationship with the person making the amendment: Applicant: 2-4-1 Nishi-Shinjuku, FR-Shuku-ku, Tokyo (δ7) Epson Corporation Address: 2-6-21-7 Kyobashi, Chuo-ku, Tokyo 104 Contents of amendment 1. In the second line from the bottom of page 3 of the specification, the phrase "outside the liquid crystal cell" is amended to read "inside the liquid crystal cell."

Claims (1)

[Claims] 1. A liquid crystal display device having a liquid crystal layer sandwiched between at least a pair of opposing electrode substrates, wherein at least one of the glass substrates has a thickness of 0.2 W+ or less.