JPH02199747A - Color cathode-ray tube - Google Patents

Abstract

PURPOSE:To enable the maintenance of a good image picture without having any effect on color purity by providing a layer of a material having low electron beam permeability on the electron gun side of the intermediate boundary region part of the dot or stripe of a heterochromatic phosphor adjacent to a phosphor film or the electron gun side of a portion corresponding to the region part of an aluminium film. CONSTITUTION:A layer 5 of a material having low electron beam permeability is disposed on the electron gun side of the intermediate boundary region part of the dot or stripe 3 of a heterochromatic phosphor adjacent to a phosphor film or the electron gun side of a portion corresponding to the region part of an aluminium film, and an electron beam for making a phosphor of a specified color luminescent is restrained from making the adjacent phosphor of another color luminescent. Hence, the intermediate boundary part of the dot or stripe of the adjacent heterochromatic phosphor is extended, and conversely, the area where the dot or stripe of the phosphor is freely irradiated with the electron beam is narrowed, so that the generation of poor color purity can be suppressed even if doming of the shadow mask occurs.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a shadow mask type color cathode ray tube that does not cause deterioration in color purity even when locally displayed on a screen with high brightness.

[Prior Art] In a shadow mask type color cathode ray tube, of the electron beam emitted from the W gun, relatively few electrons pass through the holes in the shadow mask and excite the phosphor.1. The remaining large number of electrons collide with the shadow mask and impart their kinetic energy to the shadow mask, increasing its temperature. Heat dissipation from the shadow mask is achieved by radiation and conduction.

Large, bright screens are preferred, but if a large amount of high-energy electrons collide inside a large-area shadow mask to display a bright screen, the area will become hot. In order to display high definition, it is necessary to make small holes in the shadow mask at a fine pitch, and for this purpose, it is better for the thickness of the shadow mask to be as thin as possible.

Therefore, in the case of a bright display on a large screen or a high-definition, bright and easy-to-see display, it becomes difficult for the shadow mask to dissipate heat through conduction, and the temperature near the center increases, and the temperature of the shadow mask increases on average as a whole. However, in the case where the shadow mask holder expands in a negative manner, various measures have been taken for the shadow mask holding part, and some results have been achieved. If this occurs, the corresponding portion of the shadow mask generates a large amount of heat, resulting in a large temperature rise, which causes a so-called doming phenomenon in which the shadow mask locally expands significantly. As a countermeasure against doming, as a shadow mask material,
For example, Japanese Patent Application Laid-Open No. 62-31925 discloses the use of Amber (trade name), which has a low coefficient of thermal expansion, but it is hard and difficult to process, and it is difficult to form a blackened film on its surface. A problem has arisen.

[Problem to be Solved by the Invention] When doming of the shadow mask occurs, a part of the electron beam that should be excited by impinging on a dot or stripe of a phosphor of a certain color is caused by adjacent phosphor of another color. It hits the dots or stripes on the body and excites them. That is, doming causes one color purity defect.

SUMMARY OF THE INVENTION An object of the present invention is to provide a color cathode ray tube that can suppress the occurrence of poor color purity even if doming of a shadow mask occurs.

[Means for Solving the Problems] In order to achieve the above object, in the present invention, an aluminum film is formed on the electron gun side of a phosphor film in which phosphors of each color are arranged in a dot shape or a strip shape. In a shadow mask type color cathode ray tube, the phosphor film has a boundary region located between adjacent dots or stripes of different color phosphors on the electron gun side, or corresponds to the region of the aluminum film. A layer of material with low electron beam transmission rate is placed on the electron gun side of the part, so that the electron beam for making a phosphor of a specific color emit light can cause adjacent phosphors of other colors to emit light. I tried to prevent it from happening.

As a material with low electron beam transmittance, it is best to use a material with an atomic number higher than that of aluminum. The boundary area between the color phosphor dots and stripes is wider than before, and conversely, the area where the phosphor dots and stripes are freely irradiated by the electron beam is (
If the shadow mask and the phosphor film are in the correct relative positions, the shadow mask will pass through the hole in the shadow mask. The electron beam that should emit phosphor dots or stripes of a certain color is 1 g! ! It does not illuminate adjacent dots or stripes of phosphor of another color.
Even if such correct relative positioning is disrupted by shadow mask doming, if properly designed it will still illuminate adjacent dots or stripes of phosphor of a different color for the intended purpose. The deviation in the irradiation position of the electron beam is slight. Therefore, according to the present invention, even if the peripheral boundary line of the part of the phosphor dot or stripe facing the electron gun, where the electron beam can be freely irradiated, moves inward even slightly, the effect is large and many In this case, color shift will not occur.

By implementing the present invention, the total amount of electron beams that cause the phosphor to emit light may be reduced to some extent, and theoretically it may become slightly darker. A decrease in brightness is usually not a concern.

[Example] FIG. 1 is a cross-sectional view of a main part of a phosphor film according to the present invention, and in the figure,
1 is a glass bulb panel, 2 is a so-called black matrix that fills the panel surface side in the middle boundary area of dots or stripes of different colors of phosphor to improve display contrast, and 3 is a dot or stripe of phosphor. , 4 is an aluminum film (metal back film), and 5 is an electron beam shield according to the present invention. After forming phosphor stripes (dots) 3 and aluminum film 4 by a known method, a polyvinyl alcohol/ammonium dichromate based photosensitive resin is applied, and three-color phosphor stripes are formed by a known method. (
Dots) The organic photosensitive resin film is left only in the corresponding positions. Thereafter, a material having low electron beam transmittance, such as aluminum, such as silver, is applied onto the aluminum film, which has a mixture of areas corresponding to the phosphor stripes covered with the organic film and areas corresponding to the exposed boundary areas between the stripes. First, a metal with a higher atomic number is deposited using a vacuum evaporation method to form a metal film.If the so-called baking (heating treatment at high temperature in the atmosphere) is performed in the usual way, the organic film will burn, so the organic The metal film on the coating stripes (dots) is in a state where it can be easily peeled off.

By lightly blowing an air stream, the electron beam shield can be placed in a predetermined position and shape.

In addition, after forming the aluminum film, a positive photoresist such as a naphthoquinone azide compound containing the above-mentioned beam-shielding metal and which becomes soluble upon light irradiation is coated, and the coating is applied in a well-known manner, corresponding to the three colors of red, blue, and green. A beam shield can be formed at a predetermined position by exposing the position to light and performing development.

In the above-mentioned multiple exposure steps, a specific shadow mask paired with the valve panel is always used as the jS light mask, so that the effect of mask displacement does not become a problem.

[Effects of the Invention] As explained above, according to the present invention, a beam shielding material similar to a shadow mask is formed in the close vicinity of the phosphor film. Even if the hitting position moves slightly, the color purity is hardly affected and a high-quality image can be maintained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of a phosphor film according to the present invention. 1... Glass bulb panel, 2... Black matrix, 3... Fluorescent dots or stripes.

Claims (1)

[Scope of Claims] 1. A shadow mask type color cathode ray tube in which an aluminum film is formed on the electron gun side of a phosphor film in which phosphors of each color are arranged in dots or stripes. on the electron gun side at a boundary region between adjacent dots or stripes of different color phosphors of the film, or on the electron gun side at a region corresponding to the region of the aluminum film,
A color cathode ray tube characterized by having a layer of material with low electron beam transparency. 2. The color cathode ray tube according to claim 1, wherein silver, barium, tin, or bismuth, which has a higher atomic number than aluminum, is used as the material having low electron beam transparency.