Nippon Sheet Glass Company, Limited

Hitachi, Ltd.

Yoshiyuki Hanada

Yasuhiko Uehara

Yasukazu Morita

Hidemi Nakai

Masafumi Seki

Michihisa Maeda

Ryoichi Sugawara

A cathode-ray tube having a face plate which includes a phosphor layer provided at the inner surface side of a glass plate and an optical interference filter provided between the phosphor layer and the inner surface of the plate. The optical interference filter is constituted by high- and low-refractive index layers. The outermost layer of the optical interference filter in contact with the phosphor layer is an Al.sub.2 O.sub.3 layer or a ZrO.sub.2 layer having a physical thickness of 10 nm or more. The high-refractive index layer of the optical interference filter preferably consists of TiO.sub.2, and its low-refractive index layer preferably consists of Al.sub.2 O.sub.3.

Cathode-ray tube with interference filter

In a demultiplexing and/or multiplexing optical circuit of the invention, a groove for arranging a filter in an optical waveguide is arranged to be perpendicular to a pair of parallel opposing sides of a substrate for constituting the optical circuit. A plurality of demultiplexer and/or multiplexer can be formed simultaneously, and a high machining precision can be obtained relatively easily.

Demultiplexing and/or multiplexing optical circuit

Growing community of inventors

Tsukuba, Japan

Yoshiyuki Hanada