JPS61190378A - Color filter for image display - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a color filter for image display used in a display element such as a liquid crystal display element, and more particularly to a filter that displays multiple colors through additive color mixing.

[Background of the invention]

Conventionally, this type of color filter is one in which red (R), green (G), and blue (B) color unit filters 1, 2.3 are arranged in a mosaic pattern as shown in Figure 1 (Nikkei Electronics). 1984-9-10, p215), or one arranged in a striped pattern as shown in Figure 2 (Casio Computer Co., Ltd. Catalog mcRD8410TP, 1)
However, in both cases, the area of each color unit filter is the same.

By the way, in a color liquid crystal display element using such a color filter, for example, the displayed color is determined by the color of the color filter. Therefore, RGB 3
In order to display white with color filters, it is necessary to balance the colors between each color filter, but in general, with color filters, those with high transmittance and brightness have low color purity, and those with high color purity have low color purity. Transmittance tends to be low. Conventionally, therefore, a method has been adopted in which the color purity of a filter with good color purity is lowered to brighten it and match it with a filter with poor color purity. In other words, color purity is suppressed in order to obtain brightness, and visibility deteriorates accordingly.

[Purpose of the invention]

The present invention was made in view of the above circumstances, and its purpose is to provide a color filter for image display that can maintain a balance with other filters without reducing the color purity of a filter with good color purity. It is about providing.

[Summary of the invention]

In order to achieve such an object, the present invention shifts the area ratio of each color filter from 1:1 depending on its optical characteristics.

[Embodiments of the invention]

For example, a red filter with spectral characteristics as shown in (a) in Figure 3, a green filter with spectral privileges as shown in (b), and a spectral characteristic as shown in (c). When using a blue filter and making their areas equal, the x-y chromaticity coordinates when the three colors are mixed will be (0, 37, 0, 35) as shown by WI in Figure 4, which is somewhat The color becomes yellowish. Note that the curve in FIG. 4 connects the chromaticity coordinates of a monochromatic spectrum.

In this case, the x-y chromaticity coordinates of each color filter are R in the same figure.
(red), G (green), and B (blue), but in order to make white a color that is a mixture of these three colors without reducing the color purity, the area ratio of each color filter can be calculated using the following formula. Just set it so that it satisfies.

Here, α, β, r are the areas of red, green, and blue filters, x
, y, z are white tristimulus values, R1, Gi, Bi (i=x
, y+z) indicate the tristimulus values of each color filter of red, green, and blue. Now, if the chromaticity coordinates of white are (1/3.1/3) as shown by Wo in FIG. 4, then X.

Y, zO amount relationship 1/3 = X/(X + Y + Z), 1/3
=Y/(X+Y+Z), and the tristimulus values of each color filter are, therefore, the ratio of α, β, and r is α:βnear=1:1.39:1.81.

Figures 5 and 6 show specific layout examples for realizing such an area ratio. Figure 5 shows red (R),
Green (C,), f (B) color unit filter LL12.1
3 are arranged in a stripe shape, and the widths are d, 1d,, d3
a,: dt:d, = 1: 1.39:1.81
In Fig. 6, each color unit filter is arranged concentrically, and each radius rl + rt + rs is defined as r
Iarlr3 == 2.0: 3.0: 4.0
1.

By increasing the area of the filter with low transmittance and good color purity, white balance can be maintained without reducing the color purity. Note that the stimulation values are shown for the CIE 2' visual field.

〔Effect of the invention〕

As explained above, according to the present invention, by shifting the area ratio of each color filter from 1:1 according to its optical characteristics, color purity can be improved as compared to the conventional 1:1 configuration. Balance with other filters can be achieved without lowering the color purity of the filter, and visibility can be improved. Further, conventionally, the thickness of the filter has been changed in order to adjust the harshness, but this causes the thickness to vary for each color unit filter, resulting in unevenness on the filter surface. On the other hand, according to the present invention, there is an advantage that the thickness can be made uniform and the surface can be made flat.

[Brief explanation of the drawing]

1 and 2 are plan layout diagrams showing a conventional example, and FIG. 3 is a diagram showing an example of spectral transmittance characteristics of a three-color color filter.
Fig. 4 is a diagram showing the x-y chromaticity coordinates of a color 7 filter using these, Fig. 5 is a plan layout showing one embodiment of the present invention, and Fig. 6 is another embodiment of the present invention. FIG. 1.11... Red unit filter, 2.12...
Green unit filter, 3, 13... Blue unit filter. Figure 1 Figure 2 Figure 3 5ill-! ('m) Fig. 4 χ Fig. 5 Fig. 6 ゜

Claims (1)

[Claims] An image display color filter comprising unit filters of at least two colors arranged regularly, characterized in that the area ratio of each color filter is shifted from 1:1 according to the optical characteristics of each color filter. color filter.