JPS5836449B2 - Seizou Hohou - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method of manufacturing a color picture tube.

In general, a shadow mask type color picture tube is constructed as shown in Fig. 1, in which a funnel-shaped funnel 3 is joined to a neck part 2 containing an electron gun 1, and a panel 4 is sealed to this funnel 3. .

R (red), Gl), and B (blue) fluorescent surfaces (not shown) are formed on the inner surface of this panel 4, and shadow masks 5 are arranged at predetermined intervals along the fluorescent surfaces. It is set up.

During operation, the electron beam emitted from the electron gun 1 passes through the shadow mask 5 and hits the fluorescent surface, reproducing a color image.

However, at this time, if a foreign substance, particularly an insulating foreign substance, is attached to the shadow mask 5, the foreign substance has a strong adhesion force both mechanically and electrostatically, and usually does not fall off even with a slight vibration.

In addition, insulating foreign matter that has adhered to other locations within the pipe may fall off and adhere to the shadow mask 5 at any time.

As a result, transmission of the electron beam is locally inhibited, making it impossible to reproduce a normal color image.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing a color picture tube in which insulating foreign matter inside the tube is removed by heating at high temperature and applying impact.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

The reason why it is difficult to remove the insulating foreign matter adhering to the shadow mask 5 as described above is because these foreign matter are charged with static electricity when exposed to electron beam irradiation.

By the way, the charge removal time of this foreign material is Determined by dielectric constant (ε) x resistivity (ρ) and temporary constant (seconds).

For example, in the case of glass, etc., the rate of change in specific resistance due to temperature is negative and large, and the specific resistance also has negative characteristics with respect to temperature, and as shown in Figure 2, the curve showing ``Flogρ versus temperature'' is a straight line. .

Therefore, at room temperature (around 25°C), ε×ρ corresponds to several tens of days, but at a high temperature of about 200°C, ε×ρ becomes several hours.

Therefore, the insulating foreign matter can be removed from the shadow mask 5 by raising the temperature to a higher temperature.

Therefore, in this invention, high temperature heating is performed.

In this case, the entire tube is heated in an arbitrary heating step during the manufacturing process of the color picture tube.

Insulating foreign matter can be removed more effectively by applying an alternating electric field between the high-voltage electrode and the low-voltage electrode of the electron gun, applying a voltage with the opposite polarity to that during use, or applying a mechanical shock. , the insulating foreign matter is completely removed from the shadow mask 5.

Practically speaking, it is best to heat the entire tube to around 100°C and then apply a shock.

Since the manufacturing method of the present invention is configured as described above, insulating foreign matter adhering to the shadow mask can be removed very easily.

Therefore, a good color image can be reproduced without locally impeding transmission of the electron beam.

The manufacturing method of the present invention is effective not only for removing shadow masks but also for removing insulating foreign matter adhering to other parts of the pipe.

Further, it is applicable not only to the production of shadow mask type color picture tubes but also to color picture tubes having an aperture grill.

As explained above, according to the present invention, it is possible to provide a method of manufacturing a color picture tube with great practical value.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing a color picture tube, and FIG. 2 is a characteristic curve diagram showing log ρ versus temperature characteristics of insulating foreign matter attached to a shadow mask. 5...Shadow mask.

Claims (1)

[Claims] 1. A color picture tube consisting of a panel having a fluorescent surface, a funnel-shaped funnel connected to the panel and having an electron gun built into its neck, and a shadow mask disposed at a predetermined distance from the fluorescent surface. A method for manufacturing a color picture tube, characterized in that the entire picture tube is heated to a high temperature while applying impact to remove insulating foreign matter inside the tube.