JPS5842145A - Cathode ray tube - Google Patents

Abstract

PURPOSE:To produce a cathode ray tube having high contrast by constructing the phosphor face of panel with the phosphor substance where the pigment having non-ohmic current and voltage characteristic and containing the black grey color or the black color including the blue black is added. CONSTITUTION:The black pigment having the non-ohmic voltage-current characteristic is employed to improve the contrast of the reproduced picture image caused by the background light emission of the phosphor material due to the in-tube dispersion electron or the reflection electron.

Description

[Detailed description of the invention] The present invention relates to a fluorescent surface structure for a cathode ray tube.

For example, the phosphor surface of a color picture tube has a dot-shaped or band-shaped phosphor layer regularly deposited on the inner surface of the panel, and a metal back layer made of vapor-deposited aluminum film to increase brightness. The electron beam from the electron gun is fluoresced by a deflection device, and the surface is scanned horizontally and vertically in two directions.
The image is now played.

The image quality of this reproduced image is determined by resolution, contrast, brightness, etc. Among these, the resolution is determined by the resolving power of the color picture tube, the resolving power of the electron gun, and the shadow mask provided opposite the fluorescent surface. The brightness is determined by the shape and pitch of the electron beam holes, and the brightness is determined by the phosphor forming the phosphor layer, the metal back layer, the intensity of the electron beam striking the phosphor layer, etc.

Furthermore, in order to improve image quality, it is essential to improve contrast. For example, JP-A-52-107770
As shown in I: In order to improve the contrast of the color picture tube screen under bright outside light, green, blue,
A method has been proposed in which a black pigment is added to at least one color of the phosphor in groups of red phosphor dots or stripes. In addition, in order to improve the contrast of the reproduced image itself, I
A method has been proposed for improving the brightness ratio between the peak brightness and black level of an image by lowering the black level brightness by changing the dead voltage value of the fluorescent surface.

The present invention uses a pigment having the following properties, that is, voltage/current characteristics are non-ohmic and is black. To improve the deterioration of the contrast of the reproduced image itself due to the background light emission of the body, and also to improve the contrast of the screen under bright external light, and to obtain a cathode ray tube with good contrast image quality.

Next, examples of the present invention will be shown.

(Example-1) 810 and 0.01.0.
The relationship between the white brightness and black level brightness of color picture tubes manufactured by the usual method using 0.025° 0.04 and 0.051 color picture tubes and 62 color picture tubes coated with carbon black in the same way is as follows. Figure (two shown).

In Figure 1, the vertical axis t: Fi black level luminance, the horizontal axis I: white luminance, and the white dotted line indicates conventional carbon black.
The solid black circles indicate this example. From Figure 1, it can be seen that 810 is covered with Fi, c.
It can be seen that the black level brightness is better than that of the arbon b1ackc.

Also, regarding the relationship between white luminance and external light reflectance. No difference was seen between the two.

In addition, the black level brightness was measured by measuring the relative brightness of the face (panel) center part I: with white bar exposed, left and right rf = 35cm from the center of the panel, with no external light (e.g. -2) The same procedure as in (Example 1) was carried out on blue, red, and green phosphors, and the results are shown in Fig. 62, similar to Fig. 1.

Similar to (Example-1), good results were obtained. It was done.

(Example-3) One coated with 0.01゜0.025.0.04.0.05 of blue, red and green phosphor C3iC, and the same coated with carbon black. The relationship between the white luminance and the black level luminance of a monochrome tube manufactured by a conventional method is shown in Figure 5 and Figure 3 (g) in the same manner as in Figure 1.

(Example-1) and 1eii, good results were obtained for both monochrome tube effects.0 It should be noted that pigments having black color do not necessarily have to be black, but may also contain black-gray or black-blue color. Needless to say, Fi.

As mentioned above, C: the present invention (according to 2), the pigment has non-ohmic voltage/current characteristics and a black pigment is used (2) the black level brightness is good, and the in-tube scattered electron and reflected electron sensitivity = It is possible to suppress deterioration of contrast due to background light emission g2, improve contrast even under bright external light, and provide a high-contrast cathode ray tube.

[Brief explanation of drawings]

1 to 3 are characteristic diagrams in which the vertical axis C shows the black level brightness and the horizontal axis shows the white brightness. The dotted white circles show the conventional example, and the concentrated black circles show the embodiment of the present invention. (7317) Agent Patent attorney Noriyuki Chika (and 1 other person) Fig. 1 5its -j "l 5 Fig. 2 571) -II -21-DI -'a
d%Figure 3%

Claims (1)

[Claims] A cathode ray tube characterized in that the fluorescent surface on the inner surface of the panel is made of a phosphor added with a pigment having non-ohmic current/voltage characteristics and a black color including black-gray or black-blue.