JPS5816294B2 - color print - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color cathode ray tube having a shadow mask structure.

As shown in FIG. 1, a shadow mask type color cathode ray tube includes a shadow mask 1 having a large number of pores, a frame 2 to which skirt portions around the shadow mask are fixed at multiple locations, and this frame fixed to a panel 3. A shadow mask structure consisting of a bimetal 4 and a holder 5 is used.

The surfaces of the shadow mask 1 and the frame 2 must be blackened so that they can absorb light to prevent diffuse reflection of light from a light source when used for printing on a phosphor screen or the like.

One method of blackening the surface is to attach a blackening film of triiron tetroxide.

In this case, the blackened film is usually formed through the following process: degreasing and cleaning of the material → high-temperature annealing → molding → acid treatment → blackening treatment.

The acid treatment during this process is necessary in order to corrode the surface of the member with acids such as hydrochloric acid and nitric acid to make the surface rough, and if this treatment is not performed, the blackening film will not adhere well.

However, in this case, if the blackening treatment is not performed immediately after the acid treatment, rust will occur and the blackened film will not adhere properly, resulting in peeling. This caused defects such as short circuits between the gun's electrodes.

Furthermore, it requires large-scale equipment for acid treatment, resulting in high costs.

It is an object of the present invention to eliminate the above-mentioned drawbacks, form a blackened film with better adhesion than the conventional method, and improve the performance and yield of color cathode ray tubes.

The details will be explained below.

The manufacturing process of the shadow mask and frame used in the present invention is as follows.

The process of forming a material from a raw steel plate whose surface has been roughened in advance by mechanical means such as roll processing to form a component,
The blackening treatment is performed directly after the parts are degreased and cleaned, high-temperature annealing, and corrective molding processes, eliminating the need for acid treatment, which was conventionally necessary.

The roughening of the surface of the raw iron plate can be carried out, for example, by roughening the surface of a rolling roll when rolling the raw iron plate.

FIG. 2 shows an example of the surface roughness of a member in practical use, which has irregularities of 5 to 20 μm.

The present invention as described above eliminates the need for treatment equipment in the acid treatment process board, frees the time constraints from the molding process to the ripening process, facilitates handling, and prevents the peeling of the blackened film. This eliminates the occurrence of hole clogging, electrode short-circuiting, etc., resulting in significant effects such as simplification of the manufacturing process, improved performance, increased yield, and significant cost reduction.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a main part of a color cathode ray tube, and FIG. 2 is a diagram illustrating the surface roughness of a roughened material used in the present invention.

Claims (1)

[Claims] 1. It has a shadow mask structure that is manufactured from a steel plate whose surface has been roughened in advance to have an uneven surface of 5 to 20 μm, and that has been directly blackened without acid treatment through degreasing, cleaning, high-temperature annealing, and molding steps. A color cathode ray tube featuring: