Mitsubishi Denki Kabushiki Kaisha

Tetsushin Yazu

Koji Nakamura

Junko Itoh

Keitaro Tsukui

Kenichi Umino

Suguru Fujii

A glass bulb is physically reinforced to provide a tensile stress in the nearly central portion of wall thickness in the wall thickness direction and to provide a compressive stress on the surface. The physical reinforcement is specifically applied by air cooling reinforcement. The completed CRT is further shrinkage fitted so as to tighten the outer side face of a panel by a metal ring. At the time of the air cooling reinforcement, reinforcement is optimized by reinforcing the glass bulb (or the panel or a funnel) so as to be more effective by adding the stress distribution in a vacuum state of the picture tube having a rectangular screen and by the shrinkage fitting achieved by the metal ring. As a result, the problem of heavy weight, which was one of major defects of mass produced CRTs, is solved while the risk of implosion is still avoided.

Manufacturing method of picture tube

There are provided a cathode-ray tube display unit which can be manufactured with reduced weight and cost and which can have a screen plane flattened without the use of any metal band, and a method of making the same. The screen panel is previously deformed by the use of a jig and then sealingly connected to a funnel. After the jig has been removed, the interior of the display tube body is extracted to form a vacuum. The display tube body is distorted by the extraction, but such a distortion can be corrected by deformations previously applied to the display tube body. Thus, the screen plane can be flattened without the use of any metal band.

Growing community of inventors

Nagaokakyo, Japan

Tetsushin Yazu