JPH03278004A - Color filter plate for fluorescent display tube - Google Patents

Abstract

PURPOSE:To allow the conversion of the light of a fluorescent display tube to a beautiful white color by mixing red and blue dyes into transparent plastic to impart specific ray transmittance characteristics to the plastic. CONSTITUTION:The red dye, with which the ray transmissivity TRlambda at a wave length lambda(nm) is TR450=18 to 22%, TR500=2 to 6%, TR550=22 to 26%, and TR600=82 to 86%, is mixed with the transparent plastic. Further, the blue dye, with which the ray transmissitivity TBlambda at the wavelength lambda(nm) is TB450=78 to 84%, TB500=70 to 76%, TB550=42 to 48%, TB600=16 to 22%, and TB650=12 to 18% is used. The dyes are usually added in the range of 0.1 to 0.5 pts.wt. (pure dye component) per 100 pts.wt. plastic according to the thickness, etc., of a filter plate so as to obtain the required ray transmit tance characteristics. The rays of the fluorescent display tube are converted to the beautiful white color in this way and since the seeing-through of only the fluorescent display is possible, the distinct display is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a color filter plate used on the front surface of a fluorescent display tube used in electrical equipment and the like.

(Prior art and its problems) Fluorescent display tubes emit green light with high brightness, but since it is difficult to see as is, a filter plate is placed in front of the fluorescent display tube so that the display can be viewed through the filter plate.

Conventionally, this filter plate has been made by applying silk printing to a transparent plastic plate to impart desired color and light transmittance.

However, when printing, turbidity inevitably occurs, and the contrast of displayed characters when viewed through a filter plate is poor.
The problem was that it couldn't be read clearly. Further, in printing, coating unevenness occurred, and display density unevenness was likely to occur.

(Means for Solving the Problems) The present invention can convert the light from a fluorescent display tube into pure white by mixing red and blue dyes into transparent plastic to give it specific light transmission characteristics. The object of the present invention is to provide a color filter plate that eliminates the drawbacks of the above.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram showing an example of the light transmission characteristics of the color filter plate of the present invention, FIG. 2 is a diagram showing an example of the light transmission characteristics when red and blue dyes are individually mixed, and FIG. 3 is a diagram showing an example of the light transmission characteristics of the color filter plate of the present invention. This is the spectrum of green light emitted from a light display tube.

The light beam from the fluorescent display tube has a wavelength of 50 mm as shown in Figure 3.
It is a highly bright green color with a peak around 5 nm. However, this light is difficult to see, so it is preferable to convert it to white.

For this purpose, red dye is added, but in order to obtain a beautiful white color, it is important to give the filter an absorption characteristic that is opposite to the intensity of green light, and the light transmission characteristic shown by the dotted line in Figure 2 is important. The red dye obtained, that is, the light transmittance TRA at wavelength λ (nm) is TR4
5o=18-22% TR500"-6% TR550" 22-26% TR6oo=82-86% A red dye is mixed into transparent plastic.

In particular, it is important to have an absorption peak near a wavelength of 500 nm. Examples of such red dyes include anthraquinone solvent orange 71 and the like.

By adding this red dye, green fluorescent light can be converted to white, but it is also preferable that only the fluorescent display is visible from the outside and that the other background parts are not visible from the outside. In terms of appearance, it is preferable for the design to have no reddish color and be close to black.

To this end, it is conceivable to reduce the light transmittance of the filter plate as a whole, but in this case, the luminance of the fluorescent display itself decreases, resulting in a lack of clarity.

Therefore, in the present invention, a blue dye that can provide light transmission characteristics as shown by the solid line in FIG. 2 is further mixed in to impart a characteristic that parts other than the fluorescent display are not visible from the outside.

That is, the light transmittance T at wavelength λ (nm)
A blue dye is used in which Bλ TR45o=78-84% T, 500=70-76%'rB550=42-48%'rB600=16-22% Ta205=12-18%.

Examples of such dyes include anthraquinone solvent blue 93.

This dye has a high green fluorescence intensity ratio of 450 to 550.
Since it does not absorb much nm light, it does not reduce the luminance of the fluorescent light, and absorbs other light, especially from 600 to 650 nm, so that the filter becomes blackish, so that only the fluorescent display can be seen from the outside.

In addition to this 2#i dye, the light transmittance of the entire filter can be finely adjusted by adding a small amount of a smoke dye that absorbs light in all wavelength ranges.

The transparent plastic used in the present invention is preferably polyvinyl chloride resin, which is relatively inexpensive and easy to process into a thin plate, and other materials include acrylic resin, polycarbonate, and the like.

The dye is usually added in an amount of 0.1 to 0.5 parts by weight (pure dye component) per 100 parts by weight of the plastic, depending on the thickness of the filter plate, etc., so as to obtain the required light transmission characteristics. In addition, when polyvinyl chloride resin is used as the plastic, it is preferable that the dye has a melting point of 200°C or less so that it melts and is uniformly dispersed at the processing temperature of the polyvinyl chloride, and the dyes exemplified above are preferable in that sense as well. It is.

The color filter plate usually has a thickness of about 0.5 to 2 mm, and can be manufactured by press molding or extrusion molding of a sheet obtained using a calender, in the case of polyvinyl chloride resin.

(Effects of the Invention) According to the present invention, the light beam of the fluorescent display tube is converted into a clear white color, and only the fluorescent display can be seen through, so a clear display can be obtained, and the drawbacks of the conventional method can be solved. did it.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of the light transmission characteristics of the color filter plate of the present invention, FIG. 2 is a diagram showing an example of the light transmission characteristics when red and blue dyes are mixed individually, and FIG. 3 is a diagram showing an example of the light transmission characteristics of the color filter plate of the present invention. Spectrum of light rays emitted from a light display tube.

Claims (1)

[Claims] A color filter plate for a fluorescent display tube made of transparent plastic mixed with a red dye and a blue dye, which has a light transmittance T_R_λ at a wavelength λ (nm) of T_R_4_5_0=18 to 22% T_R_5_0_0=2 ~6% T_R_5_5_0=22-26% T_R_6_0_0=82-86% The light transmittance T_B_λ at wavelength λ (nm) is T_B_4_5_0=78-84% T_B_5_0_0=70-76% T_B_5_5_0=42-48 % T_B_6_0_0=16-22% T_B_6_5_0=12-18%