Hitachi, Ltd.

Tatsuya Mochizuki

Kazumasa Hirai

Hiroki Taga

Nobuhiko Hosotani

Takehiko Ueyama

Yasumasa Tsuchiya

Masakazu Tsuruoka

A shadow mask spring for a color cathode ray tube having a generally rectangular shadow mask structure including a shadow mask and a support frame for holding the shadow mask. Shadow mask springs serve for holding the support frame inside a panel having a phosphor screen adjacent thereto and engage with panel pins for holding the shadow mask structure. Each of the shadow mask springs includes L-shaped base plate and a joined plate secured to one end of the base plate. The base plate has a phosphor screen side metal portion and an electron gun side metal portion with the phosphor screen side metal portion having a smaller thermal expansion coefficient than that of the electron gun side metal portion. An other end of the base plate is secured to a side of the support frame. The joined plate is engageable with a panel pin and the secured portion of the one end of the base plate and the joined plate is located at a position closer to the phosphor screen than the secured portion of the other end of the base plate and the support frame.

Color cathode-ray tube with shadow mask having L-shaped bi-metallic springs

In order to prevent doming effect in a shadow mask of a color cathode ray tube caused by thermal expansion of the shadow mask structure produced by heating of the shadow mask due to impingement of the electron beam thereon, the shadow mask is provided with a skirt portion along at least one side thereof. The skirt portion includes a long projection portion where the shadow mask is welded to the frame, an adjacent inclined portion which decreases in length in a direction away from the projection portion. Further, a short portion is disposed therebetween the inclined portion. The inclined portion decreases in length linearly or non-linearly.

Color cathode ray tube with specific skirt portion

Shadow mask structure with specific skirt portion

Growing community of inventors

Mobara, Japan

Tatsuya Mochizuki