JPS62231218A - Matrix type liquid crystal display device - Google Patents

Abstract

PURPOSE:To eliminate a color shift and a color blur due to parallax originating from the thickness of substrates by using a couple of polarizing plates so that the relative ratio of the quantities of transmitted in three stepwise wavelength ranges is specific in the wavelength range where their spectral transmissivity characteristics are in the visible range. CONSTITUTION:The substrates 1 and 4 are so combined that a signal electrode group 2 and a scanning electrode group 5 cross each other at right angles, their peripheries are sealed with a sealant while a constant gap is left, and a liquid crystal material 6 is charged in the gap. The couple of polarizing plates 78 having such characteristics that the relative ratio of the quantity of transmitted light in wavelength ranges of 400<nm>-480<nm>, 480<nm>-590<nm>, and 590<nm>-700<nm> in the visible range is (2-5):1:(1-1.5) are arranged outside the substrates 1 and 4, and diffusion plate 8 and a light source 9 are provided outside one substrate to complete a matrix display device. Consequently, color display characteristics of color display such as a color balance, a color shift, and a color blur are improved greatly, so a color display with good visibility is made.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a matrix type liquid crystal display device using liquid crystal.

2. Description of the Related Art In recent years, liquid crystal display devices have been required to display more information, such as image display, and for this reason, there has been a shift from segment type to donmatrix type configurations, and furthermore colorization. It's moving in that direction.

Conventionally, a matrix type liquid crystal color display device has a pair of transparent electrodes each divided into strips, as shown in FIG.
．． The other electrode is used as the signal electrode 2, and the electrodes 2 or 5 are arranged so as to be orthogonal to each other.
After providing filter layers 3 of multiple colors corresponding to (formed above) (for example, authors Uchida et al., “Multi-color liquid crystal display with colored layer provided on electrodes”, 8th Liquid Crystal Symposium, 3W20, October 1982) are known, and these A pair of polarizing plates 7 used in the configuration are iodine-based polarizing plates having spectral transmittance characteristics as shown in FIG. A display device with such a configuration can display arbitrary information in color by selectively applying a voltage to each electrode group 2.5, and the driving method is usually to drive the scanning electrodes 5 at a constant rate. A so-called time-division driving method is used in which a color signal voltage is selected at a period of , and a color signal voltage corresponding to the information is applied to the signal electrode 2 in synchronization with this period.

Problems to be Solved by the Invention Matrix display devices with conventional configurations have problems with color reproducibility when displaying images. Unexamined Japanese Patent Publication No. 5, shown in Figure 3.
In the case of so-called external attachment in which the color filter 113 is formed on the outside of a pair of electrode substrates 1.4 that sandwich a liquid crystal as in the example of Publication No. 4-84997, the transparent substrate 1.4 constituting the liquid crystal cell can be However, due to the thickness of this substrate, there was a fatal drawback regarding color display. In other words, in order to obtain a clear image with good resolution, the display pixels must be made small, but in this case, when the viewing direction is angled, parallax occurs, causing color blurring or color shift in the image. There was a problem.

Therefore, as a method to improve such drawbacks, a structure in which the color filter layer 3 is formed on the inner surface of the liquid crystal cell has been proposed.Normally, the polarizing plates used in display devices with these conventional structures are made of iodine. It is a system polarizing plate, and has uniform transmittance in its spectral transmittance characteristic region. Conventional liquid crystal display devices using such polarizing plates have a drawback regarding color reproducibility of displayed color images. That is, the spectral transmission characteristics of the Leysten nematic type (hereinafter referred to as TN type) differ in the °C wavelength band due to optical rotation dispersion. That is, the TN type liquid crystal cell has the property that long wavelength component light is easily rotated and short wavelength component light is difficult to rotate, and therefore the transmittance of blue component light is poor.

Therefore, when performing color display, there is a drawback that the output light of the blue component is weak and only color images with poor color balance can be displayed.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a plurality of strip-shaped electrodes perpendicularly to each other on the inner surface of a transparent substrate sandwiching a liquid crystal, and a plurality of strip-shaped electrodes are arranged on one electrode in a plurality of colors. A filter layer is provided to configure picture elements in a matrix for displaying multiple colors, and a pair of polarizing plates having a high spectral i3 transmittance in a short wavelength region are arranged on the outside of the substrate.

Function: With the above-described configuration, the present invention ensures that the attenuation of the blue component output light caused by optical rotation dispersion is ensured by increasing the transmittance of the polarizing plate in the short wavelength region. Therefore, deterioration in color balance can be improved. Furthermore, since the filter layer is formed on the inner surface, it is possible to eliminate color shifts and color blurring due to parallax caused by the thickness of the substrate.

EXAMPLE Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 1 is a cross-sectional view schematically showing the structure of a matrix type liquid crystal color display device of the present invention, and FIG. 2 shows the spectral transmittance characteristics of a polarizing plate that is a component thereof.

2 is a transparent glass substrate, and a transparent conductive film of indium oxide containing tin is formed on this substrate 1, and a band-shaped signal electrode group 2 is provided by etching this.

Next, on this signal electrode 2, a plurality of colors (for example, RlG,
The color filter layer 3 of B) is provided.

Here, methods for forming these color filter layers include photolithographic dyeing, printing, and electrodeposition, but electrodeposition and photolithography have good alignment accuracy between the electrodes and the filter layer. Suitable for forming filter layers on fine electrode patterns.

Generally, the thicker the filter layer formed by these methods, the better the color purity, but the lower the light transmittance.

On the other hand, from the viewpoint of the characteristics of liquid crystals, the thinner the filter layer is, the more desirable it is because the thicker the film, the worse the characteristics.

Therefore, the film thickness of the color filter layer should be 1.0~
The thickness is preferably about 2.5 μm.

Next, on the other transparent glass substrate 4, a transparent conductive film of indium oxide containing tin is formed and etched to form a band-shaped scanning electrode group 5.

Each of these substrates 1.4 has a signal electrode group 2 and a scanning electrode group 5 assembled so as to be perpendicular to each other, and the periphery thereof is sealed with a sealant while maintaining a certain gap, and a liquid crystal material 6 is placed inside. Encapsulate. Thereafter, on the outside of the substrate 1.4, a second
As shown in the figure, the relative ratio of the amount of transmitted light in the visible wavelength range is 2~S:t:t~1. A matrix display device is constructed by arranging a pair of dye-based polarizing plates 7 having the characteristics of 5 (high transmittance in the short wavelength region), and further providing a diffuser plate 8 and a light source 9 on the outside of one of the polarizing plates 7. is completed.

In the liquid crystal matrix display device of the embodiment configured as described above, the scanning electrodes are selected at regular intervals, and color signal voltages corresponding to information are applied to the signal electrodes in synchronization with this selection.

For example, if a certain scanning electrode is selected and a white signal voltage is applied to the signal electrode in synchronization with this, all R, G, and B picture elements on the selected scanning electrode will be displayed. .

In this case, a display device with a conventional configuration could only display a white color with a brownish tinge because the amount of output light of the blue component was weak, but in the display device of this example, the output light intensity of the blue component was weak, but in the display device of this example, The attenuation of the output light intensity of the blue component, which had previously been present, is no longer present, and the color has been improved to standard white.

Effects of the Invention As described above, according to the present invention, color balance in color display can be improved by simple structural improvements.

Since color display characteristics such as color shift and color blurring are improved by a factor of 11, excellent color display with good visibility is possible.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view schematically showing the structure of a matrix type liquid crystal display device according to an embodiment of the present invention, FIG. 2 is a spectral transmission characteristic diagram of a polarizing plate, which is a component of FIG. 1, and FIG. is a cross-sectional view showing the configuration of a conventional matrix type liquid crystal display device,
FIG. 4 is a spectral transmission characteristic diagram of a polarizing plate used in a conventional matrix type liquid crystal display device. 1.4...Transparent electrode, 2...Signal electrode, 3...Color filter layer, 5...
Scanning electrode, 6...Liquid crystal material, 7...Polarizing plate, 8...Diffusion plate, 9...Light source. Name of agent: Patent attorney Toshio Nakao Haka1 person 1.4--
Ichishiaki Itra 2-+i Te ・' 2nd figure 79 [A CnMn

Claims (1)

[Claims] A plurality of transparent band-shaped electrodes are provided on the inner surfaces of each of a pair of transparent substrates sandwiching a liquid crystal, so as to be perpendicular to each other, and a filter layer of multiple colors is provided on one of the electrodes, thereby forming a matrix for displaying pixels in multiple colors. A transmissive display device comprising: a polarizing plate provided on the outer surface of each of the pair of substrates; and a light source provided on the outer surface of one of the polarizing plates, the pair of polarizing plates comprising:
Its spectral transmittance characteristics are 400^n^m~700^n^m
In the wavelength range of 400^n^m to 480^n^m
, 480^n^m ~ 590^n^m and 590^n^
A matrix type liquid crystal display device characterized in that a polarizing plate is used in which the relative ratio of the amount of transmitted light in each wavelength region of m to 700nm is 2 to 5:1:1 to 1.5.