Television projection system

• US 4,918,535 A
• Filed: 10/25/1988
• Issued: 04/17/1990
• Est. Priority Date: 10/25/1988
• Status: Expired due to Fees

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Grabis, Dietrich, Knoll, Peter
• Primary Examiner(s): Britton, Howard W.
• Assistant Examiner(s): Powell, Mark R.
• Application Number:
  US07/262,539
• Time in Patent Office: 539 Days
• Field of Search: 358/231, 358/237, 358/238, 358/250, 358/253, 358/254, 358/60, 358/61, 358/62, 353/77, 353/38, 353/101
• US Class Current: 348/782
• CPC Class Codes: H04N 9/3141 Constructional details thereof details not peculiar to the presence of an electronic spatial light modulator G03B21/14

Abstract

A TV display, typically derived from a high-intensity miniature cathode ray tube (1) and available on a projection screen (8) thereof is enlarged by an optical lens system and, as enlarged, projected behind a viewing screen (10) via an optical folded system. The specific arrangement of the TV tube (1) and one or more deflection mirrors (3, 4, 5) forming the optical folded system towards the viewing screen (10) permit flat and light-weight construction of the projection system.

Claims

1. A projection television system having

a miniature cathode ray tube (CRT), with a TV screen (8) to provide a TV display, and

a viewing screen (10) for viewing a projected image of the TV display on the TV screen (8);

said TV screen (8) being positioned laterally with respect to the viewing screen and at least approximately parallel to the central axis of the viewing screen (10);

a plurality of mirrors (3,

     4) in an optical path between the TV display on the TV screen and the viewing screen (10) for deflection of the display from the TV screen (8) toward the viewing screen (10), and

an optical enlarging lens system (2), located in said optical path between the TV screen (8) and said mirrors (3,

     4),

wherein said optical enlarging lens system (2) is arranged to project the TV display from the TV screen (8) of the cathode ray tube (1) onto a first one of said first mirrors (3), and from the first mirror into a second mirror (4) located at least approximately parallel to said first mirror (3) and laterally offset with respect thereto, the display being then projected from said second mirror (4) onto the rear of said viewing screen (10).

2. A projection television system having

a miniature cathode ray tube (CRT), with a TV screen (8) to provide a TV display, and

a viewing screen (10) for viewing a projected image of the TV display on the TV screen (8), said TV screen (8) being positioned behind said viewing screen (10);

a plurality of mirrors (3,4,5) in an optical path between the TV display on the TV screen (8) and the viewing screen (10) for deflection of the display from the TV screen (8) toward the viewing screen (10), and

an optical enlarging lens system (2), located in said optical path between the TV screen (8) and said mirrors (3,4,5);

said viewing screen (10) being forwardly tilted or tipped with respect to a viewer;

and wherein the optical enlarging lens system (2) directs the TV display from the TV screen (8) of the CRT (1) onto a first deflection mirror (3), then onto a second deflection mirror (4), and then onto a third deflection mirror (5), said first, second and third deflection mirrors each being positioned approximately parallel to respective lines defined by upper and lower edges of the viewing screen (10) said mirrors, in combination with said lens system, forming an optically folded system.

3. A projection television system having

a miniature cathode raty tube (CRT), with a TV screen (8) to provide a TV display, and

a viewing screen (10), essentially vertically positioned, for viewing a projected image of the TV display on the TV screen (8), said TV screen (8) being located laterally behind said viewing screen (10);

a plurality of deflection mirrors (3,4,5) in an optical path between the TV display on the TV screen (8) and the viewing screen (10) for deflection of the display from the TV screen (8) toward the viewing screen (10), and

an optical enlarging lens system (2), located in said optical path between the TV screen (8) and said mirrors (3,4,5);

wherein the optical lens system (2) directs the TV display from said TV screen (8) of the cathode ray tube in the direction of the viewing screen (10), the viewing screen (10), in combination with said lens system (2) and first, second, and third ones of said deflection mirrors (3,4,5) forming an optically folded system, said first, second and third deflection mirrors being located opposite each other for repeated deflection and progressive enlargement of said TV display.

4. An image projection system having

an image generating means (1) having an image display surface (8);

a viewing screen (10) for viewing the image displayed on said surface (8);

said image generating means (1) being positioned behind said viewing screen (10);

said viewing screen (10) being forwardly tilted or tipped with respect to a viewer;

and a plurality of deflection mirrors (3, 4,

     5) in an optical path between said display surface and the viewing screen (10) for deflection of the image on the display surface toward the viewing screen,

and an optical lens system (2), located in said optical path between said surface and said mirrors,

wherein the optical lens system (2) directs the display from the display surface (8) of the image generating means (1) successively onto a first deflection mirror (3), a second deflection mirror (4), and then onto a third deflection mirror (5), said first, second and third deflection mirror each being positioned approximately parallel to respective lines defined by upper and lower edges of the viewing screen (10) and, in combination with said lens system, forming an optical folded system.

5. An image projection system having

an image generating means (1) having an image display surface (8);

a viewing screen (10), essentially vertically positioned, for viewing the image displayed on said surface (8);

said image generating means (1) being located laterally behind said viewing screen (10);

and a plurality of deflection mirrors (3, 4,

     5) in an optical path between said display surface and the viewing screen (10) for deflection of the image on the display surface toward the viewing screen,

and an optical lens system (2), located in said optical path between said surface and said mirrors,

wherein the optical lens system (2) directs the display from the display surface (8) of the image generating means in the direction of the viewing screen (10), the viewing screen (10) in combination with said lens system (2) and a first, a second, and a third deflection mirror (3, 4,

     5) forming an optically folded system.