JPS59210481A - Color liquid crystal display unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color liquid crystal display device comprising a light shutter that utilizes the electro-optic effect of liquid crystal, a color filter having wavelength selective transmittance in the visible wavelength range, and a light source. More specifically, the present invention relates to a color liquid crystal display device using a light source having peaks in the red, blue, and green wavelength regions within the emission spectrum.

As shown in FIG. 1, a color liquid crystal display device capable of displaying full color is composed of a liquid crystal light shutter 2 provided with a color filter 1 and a light source 5, and visually recognizes light 4 modulated by screen display information. 5 is a reflecting plate. In terms of structure, most transmission types have a light source placed on the back side of the liquid crystal light shutter, but reflective types have a light source placed in front of the liquid crystal light shutter. The color filter and liquid crystal light shutter are as shown in Figure 2 (a) and (b).
) In the case of additive color mixing, R (red), Q (green), and B (blue) are dispersed in a plane; (b) In the case of subtractive moisture, C (cyan)
, Y (yellow), and M (magenta) are arranged one on top of the other.

In both methods, a light source light with a flat spectrum is attenuated by a color filter and a liquid crystal light shutter that modulates the unnecessary wavelength range, and a spectrum corresponding to the color and brightness to be displayed is synthesized.

For a color liquid crystal display device based on such a principle, a light source having a flat spectrum has conventionally been considered desirable in terms of color reproduction. As a light source with a flat spectrum, C
There is a C light source based on the IE color system. Moreover, with a light source having a flat spectrum, the range of colors that can be displayed is limited by the performance of the color filter. Figure 3 Oxygen is R-G
-B filter and CIE-C light source are combined. The one-dot chain line in FIG. 3 is the color range of the color CRT. None of them have perfect color reproducibility. In particular, color filters use absorption of pigments, making it impossible to reproduce colors with high color purity (close to monochromatic light), and the color range is also narrow.

The present invention was devised in view of these drawbacks, and R
The object of the present invention is to realize a color liquid crystal display device that is bright, has high color purity, and has excellent color reproducibility by combining a light source having an emission peak at a wavelength corresponding to -GB and a color filter.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 4 shows the emission spectrum of a three-wavelength band type fluorescent tube as a light source. It can be seen that sharp peak light emission occurs in the RGB wavelength domain. Figure 5 shows R-G
-B- Transmission characteristics of the transmission color filter. 6th
The figure shows the spectrum after the light source system of FIG. 4 passes through the color filter fa of FIG. The dashed-dotted line indicates B, the solid line indicates G, and the broken line indicates B, respectively.

When a three-wavelength band emission type fluorescent tube is used, as shown in FIG. 6C, the light emits a sharp peak even after passing through the color filter, and the light is perceived as three primary colors with high color purity.

Using this primary color system expands the range of colors that can be reproduced.

The peak emission wavelength of the three-wavelength band type fluorescent tube can be varied depending on the phosphor used. The emission range of a commercially available three-wavelength emission type fluorescent tube is 450 nm, 5
Many have emission peaks around 40 nm and 610 nm, and most of them can be applied to the present invention. Figure 4 also shows the characteristics of a commercially available three-liquid long-range fluorescent arc tube.

The above is a case where an R-G-B transmission type color filter is used, but the same result can be obtained even if a Y-0-M mixed color filter and a three-wavelength band emission type fluorescent tube are used. A system with high color purity and excellent color reproducibility can be obtained. This is because the additive color system adds light with wavelengths limited to the R, G, and B wavelength regions, whereas the additive color system adds light with wavelengths limited to the R, G, and B wavelength regions, whereas the white color system sequentially adds components in the R, G, and B wavelength regions. This is a subtractive difference, and if the emission spectrum of the source light source has peak emission in the mobile range in the R, G, and B wavelength ranges, the transmitted light will be a subtractive mixture of Y-C and IA. Even so, the light becomes narrow band monochromatic light.

FIG. 7 shows an emission spectrum when a CRT is used as a light source. It can be seen that light is emitted corresponding to the R wavelength range, G wavelength range, and B wavelength range. This means that one pixel has many R-
This is achieved by arranging a point light source that emits G-B light, and by mixing a fluorescent substance corresponding to R-G-B and applying it to a fluorescent surface. Even when a CRT is used as a light source, compared to a light source with a flat spectrum, color purity does not depend only on the performance of the color filter, but also on the light emission characteristics of the light source, resulting in high color rendering and excellent color. Reproducibility can be achieved.

Similarly, by blending dopants for the entire emission spectrum of an electroluminescent device (EL), the R wavelength region, G wavelength region,
A fluorescent tube that emits light in a narrow band in the B wavelength range, and a three-wavelength range emitting type fluorescent tube, C
Effects similar to RT can be achieved.

As explained above, according to the present invention, the color purity, color, and FI reproducibility do not depend solely on the performance of the color filter, and the narrow band emission compatibility of the light source works in a complementary manner, which could not be expressed conventionally. It becomes possible to display different colors.

Therefore, the present invention is effective as long as the light source emits peak light in the R-G-B region, and light sources other than the above embodiments may be used.

The present invention is particularly effective in providing excellent color reproducibility and color purity in the field of color display devices.

FIG. 1 is a block diagram of a general color liquid crystal display device.

Nizuki is Hiburatsu 4's match, (B11
-Tepuro.

FIG. 2 is a configuration diagram of a color filter.

(a) is the case of additive color mixing, and (b) is the case of subtractive color mixing.

FIG. 3 is a diagram showing the color range on the OIE color coordinate system.

FIG. 4 shows an example of the emission spectrum of a three-wavelength band emission type fluorescent tube. λ is the strength of an arbitrary scale, and λ is the wavelength.

FIG. 5 shows the transmission characteristics of the color filter.

T indicates transmittance.

FIG. 6 shows the spectrum of the light source light after it passes through the color filter.

FIG. 7 is an example of an emission spectrum when a CRT is used as a light source.

1...Color filter 2...LCD light shutter 3...Light source that's all Applicant: Suwa Seikosha Co., Ltd. Figure 1

Claims (1)

[Claims] (1) An optical shutter that utilizes the electro-optic effect of liquid crystal;
1. A color liquid crystal display device comprising a color filter and a light source, characterized in that the light source is a light emitter having emission peaks in red, blue, and green wavelength regions. (2) The color liquid crystal display device according to claim 1, wherein the color liquid crystal display device uses a three-liquid long range emission type fluorescent discharge tube as a light source. (6) The color liquid crystal display device according to claim 1, wherein the color liquid crystal display device uses a cathode ray tube as a light source. (4) The color liquid crystal display device according to claim 1, wherein the color liquid crystal display device uses an electric field generating element as a light source.