Projection cathode-ray tube having enhanced image brightness

• US 4,642,695 A
• Filed: 10/30/1984
• Issued: 02/10/1987
• Est. Priority Date: 11/04/1983
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Iwasaki, Yasuo
• Primary Examiner(s): Chin, Tommy P.
• Application Number:
  US06/666,422
• Time in Patent Office: 833 Days
• Field of Search: 358/60, 358/64, 358/73, 358/231, 358/237, 340/700, 340/720, 313/461, 313/465, 313/473, 313/477 R, 313/482
• US Class Current: 348/781
• CPC Class Codes: H01J 29/20 characterised by the luminescent material
• CPC Class Codes: H01J 29/28 with protective, conductive or reflective layers

Abstract

A projection cathode-ray tube comprises a vacuum vessel (10) having a face plate (7), an interference thin film (20) on the inner surface of the face plate, a phosphor layer (8) on the interference thin film, a metal-back film (9) on the phosphor layer and an electron gun within the vessel. More than 30% of the total luminous flux from an emission point in the phosphor layer to which the electron beam of the electron gun is applied exists within a divergent angle of ± 30° in the direction normal to the face plate.

Claims

1. A projection cathode-ray tube comprising a vacuum vessel having a face plate, a phosphor layer on an inner surface of said face plate, an interference thin film between the inner surface of said face plate and an outer surface of said phosphor layer, a metal-back film on an inner surface of said phosphor layer and an electron gun within said vessel, wherein an image on said phosphor layer is enlarged and projected on a screen located at a given distance ahead through a projection lens in front of said face plate, such that more than 30% of all luminous flux emitted from an emission point in said phosphor layer is concentrated within a divergent angle of ±

30°

in a direction normal to said face plate.

2. A projection cathode-ray tube in accordance with claim 1, characterized in that phosphor particles in said phosphor layer are of plate-like crystal parallel to said face plate.

3. A projection cathode-ray tube in accordance with claim 1, characterized in that phosphor particles in said phosphor layer are of plate-like cyrstal parallel to said face plate.