JPH0222972B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shadow mask type color picture tube, and in particular, to prevent deformation of a shadow mask structure consisting of a shadow mask and/or a mask frame that holds the shadow mask during a heating step during the processing of the color picture tube. The present invention also relates to a method of manufacturing a shadow mask type color picture tube that can improve white balance.

In the shadow mask type color picture tube, a fluorescent screen is formed on the inner surface of the panel and has a regularly provided dot-shaped or striped phosphor layer that emits red, green, and blue colors through a shadow mask.
A baking process at 420°C to 460°C and a sealing process between the panel and funnel are required. However, the shadow mask and mask frame that make up the shadow mask structure are generally made of press-molded products such as iron and SUS, and when subjected to the heating process described above, the process distortion and materials inherent in these shadow masks and mask frames are removed. So-called sagging occurs under high temperatures, and the position of the shadow mask deviates from the position at which the fluorescent screen was formed, resulting in a decrease in color purity when the product is manufactured. To prevent this phenomenon, conventionally the shadow mask structure is attached to the inner surface of the panel via the shadow mask support structure, and then stabilized at 440 to 460 degrees Celsius for 40 to 60 minutes as a pretreatment to form a fluorescent surface. It has become customary to carry out treatments.

However, this stabilization process not only requires a huge amount of thermal energy, but also requires long storage times to cool down the heated panel and shadow mask structure, which have a large heat capacity, to around room temperature, which is suitable for forming a fluorescent screen. This was one of the drawbacks in the manufacturing process of shadow mask type color picture tubes.

The present invention has been made in view of the above-mentioned conventional drawbacks. It is an object of the present invention to provide a method for manufacturing a shadow mask type color picture tube that can reduce thermal energy and complete stabilization processing in a short time.

As mentioned above, the purpose of the stabilization treatment is to prevent processing distortion and material stiffness from occurring in the shadow mask structure, and to avoid damage to the shadow mask structure, especially the electron beam passage hole and the fluorescent screen, by heat treatment after forming the fluorescent screen. The goal is to prevent misalignment of the three color phosphor layers that make up the phosphor layer.

In particular, problems include welding distortion at the part where one end of the shadow mask support structure is welded and fixed to the shadow mask and/or the mask frame that holds the shadow mask, and the stress caused by the SUS plate spring that constitutes the shadow mask support structure and the bimetallic structure at high temperatures. This is high temperature creep (thermal fatigue).

For example, in the case of a 9V class shadow mask type color picture tube, the position of the shadow mask shifts about 5/100 of the way toward the electron gun in the tube axis direction due to the first heat treatment, and the bending height of the leaf spring of the shadow mask support structure decreases due to thermal fatigue. It decreases by nearly 30%. This phenomenon decreases to nearly 1/10 in the second and subsequent heat treatments, and becomes an almost non-problematic amount. Therefore, if a treatment having the same effect as the heat treatment applied after the formation of the fluorescent surface is applied to the shadow mask support structure and the welded portion of the shadow mask support structure to the shadow mask structure, almost the same effect as heat treating the entire panel and shadow mask structure can be obtained. be able to.

Next, a specific method of the present invention will be explained using a 9V class shadow mask type color picture tube as an example.

First, we installed a shadow mask support structure consisting of a 0.65t SUS302 plate spring and a 0.76t bimetal.
Weld and fix to the 1.2t SPC mask frame. Next, the shadow mask support structure is fixed to a non-flammable, non-conducting jig that provides the same force as when it is attached to a panel, and the output is 300 to 400 KHz, the output is around 5 KW, and the coil diameter is 50.
Rapidly heat to approximately 460°C using high-frequency heating equipment before and after O/cooling.

This type of processing can generate the same amount of deviation and sagging as conventional stabilizing processing, and after this, a shadow mask is welded to the mask frame and a fluorescent surface is formed to perform conventional stabilizing processing. We were able to obtain a color purity characteristic that was almost comparable to that of a shadow mask type color picture tube manufactured using the same technology.

According to the experimental results, by heating at a peak value of 400°C to 500°C, it is possible to eliminate misalignment and sagging due to processing distortion without impairing the quality of each part, and it is possible to improve the color purity characteristics. It was possible to obtain a good shadow mask type color picture tube.

As described above, the method for manufacturing a shadow mask type color picture tube of the present invention locally heats the shadow mask support structure and the fixing portion between the shadow mask support structure and the shadow mask structure, without heating the panel or the shadow mask structure, which have a large heat capacity. By doing so, it is possible to obtain an effect equivalent to that of conventional stabilizing treatment, and its industrial value is extremely large.

Claims (1)

[Claims] 1. A panel having a fluorescent screen adhered thereon, in which a dot-shaped or striped phosphor layer that emits light in red, green, and blue colors is regularly provided, and a predetermined interval between the fluorescent screens. A shadow mask structure comprising a shadow mask arranged as shown in FIG. In the method for manufacturing a shadow mask type color picture tube, one end of the shadow mask support structure is fixed to the shadow mask structure, and then a force equivalent to that when the shadow mask support structure is attached to the panel pin is applied to the shadow mask support structure. A method for manufacturing a shadow mask type color picture tube, comprising locally heating and air cooling the shadow mask support structure and the fixing portion between the shadow mask support structure and the shadow mask structure at a temperature having a peak value of 400°C to 500°C. .