Hitachi, Ltd.

Takehiko Ueyama

Masahiro Nishizawa

Eiichi Yamazaki

Iwao Ogura

Nobuhiko Hosotani

Yoshiyuki Odaka

Yasumasa Tsuchiya

Tatsuya Mochizuki

Hiromi Matsuda

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

A light exposing prism system for use in light exposure process for forming a phosphor plane of a color picture tube is disclosed. The prism system is arranged between a panel of the color picture tube and a linear exposing light source and includes a plurality of small prisms which are arranged transversely to an axial line extending through a center of the panel and a center of the light source and to a longitudinal axis of the light source. The prism system is adapted to be oscillated in the direction of arrangement of the small prisms. Pitch of the arrangement of the small prisms is within a range of 0.05 mm to 3.0 mm, preferably 1.0 mm to 3.0 mm.

Light exposing prism system for use in forming phosphor plane of color

An exposure method and apparatus for forming phosphor stripes or black matrix stripes on the inner surface of a face plate of a stripe phosphor screen type color picture tube or CRT (cathode-ray tube), in which a single linear light source is used as the exposure light source, and a prism device including many juxtaposed prisms is disposed between the linear light source and the face plate. The taper angle of the prisms is continuously changed so that the single linear light source can be observed as a plurality of discontinuous virtual linear light sources at whatever point on the inner surface of the face plate, and the virtual linear light sources have a most suitable center-to-center distance at individual positions on the face plate. The above arrangement eliminates the necessity for drive means for moving the linear light source, and a phosphor screen having three color phosphor stripes of satisfactorily uniform width can be formed on the entire inner surface of the face plate with use of the single linear light source.

Method and apparatus for exposure of phosphor screen

A method of forming a stripe type phosphor screen on inner surface of a face plate of a color picture tube or CRT through the irradiation with light stripes. A single linear light source is employed in combination with a plurality of juxtaposed prisms between the face plate and the linear light source with the taper angles of the prisms being continuously varied so that a plurality of virtual linear light sources may be observed from any points on the inner surface of the face plate with the distances between mid-points of the virtual linear light sources taking optimum values at respective positions on the inner surface of the face plate. With such arrangement, an improved phosphor screen composed of phosphor stripes of three colors having uniform stripe width can be formed over the whole inner surface of the face plate by using a single linear light source without requiring driving apparatus for moving the light source to different positions.

Method and apparatus for forming phosphor screen of color picture tubes

A method for manufacturing a fluorescent screen of a color picture tube by the steps of forming a coating of opto-hardening material on the inner surface of the faceplate of the panel of a color picture tube and exposing to a light and hardening selectively the coating thereby to form a matrix of stripes of the opto-hardening material, in which the selective exposure is performed by projecting a light derived from a light source having a predetermined width from each of at least two positions which are separated from the inner surface of the faceplate by a predetermined distance and also separated from each other onto the coating of the opto-hardening material formed on the faceplate through a slot of a predetermined width of a mask located between the inner surface of the faceplate and the light source, whereby the width of the stripe changes little even when the luminous intensity of the light source changes.

Growing community of inventors

Mobara, Japan

Takehiko Ueyama