Fresnel lens projection system with high gain screen

Claim 2

A projection system of the type useful in projecting an image or series of images from an image source comprising means including a screen having a gain greater than 13 for displaying images, means for providing an image source, a lens system having a plurality of spaced apart elements, said lens system having an aspect ratio of 3:4, an apparent speed of substantially f/1.4 and a focal length of substantially 280 mm, at least one of said plurality of elements being disposed in substantially parallel relation to said image source means, and another one of said plurality of elements disposed substantially orthogonally relative to at least one other of said plurality of elements.

Claim 3

The system of claim 1, wherein the number of said plurality of elements is three.

Claim 4

The system of claim 2, further including lens folding means disposed between two of said elements.

Claim 5

The system of claim 3, wherein said lens folding means is angularly disposed 45 degrees relative to said other elements.

Claim 6

The system of claim 3, wherein said image folding means includes means for defining the aperture of said lens system.

Claim 7

The system of claim 2, wherein the one of the three elements disposed closest to the screen defines an included angle of about 10 to 13 degrees between the screen and the lens closest to the screen.

Claim 8

The system of claim 6, wherein the image source means is angularly displaced about 30 degrees from the horizontal, and wherein the projection screen is angularly displaced about 17 to 20 degrees from the vertical.

Claim 9

The system of claim 1 wherein said elements are Fresnel lenses.

Claim 10

The system of claim 1, wherein said screen means has a gain of 17.

Claim 11

The system of claim 1, wherein said image source means is a cathode ray tube.

Claim 12

A projection system suitable for projecting images from an image source onto a high gain viewing surface comprising, a lens system having a focal length of approximately 280 mm and having means including a proximal end disposed approximately 5.7 inches from said image source for receiving images from said image source and means including a distal end for projecting images at a horizontal beam angle of at least approximately 20° onto said viewing surface, said proximal end and said distal end being disposed at a substantially perpendicular relationship with respect to each other, wherein the distal end of said lens system is disposed in a non-parallel relationship with respect to said viewing surface so that the viewing surface is displaced from perpendicularity with the incident beam of the projected images by approximately 10 to 13 degrees, with the top of the viewing surface being farther away from the distal end of said lens system than is the bottom of the viewing surface, said viewing surface having an optical gain greater than approximately 13.

Claim 13

A projection system suitable for projecting images from an image source onto a high gain viewing surface comprising, a lens system having a focal length of approximately 280 mm and having means including a proximal end disposed approximately 5.7 inches from said image source for receiving images from said image source and means including a distal end for projecting images at a horizontal beam angle of at least approximately 20° onto said viewing surface, said proximal end and said distal end being disposed at a substantially perpendicular relationship with respect to each other, wherein the distal end of said lens system is disposed in a non-parallel relationship with respect to said viewing surface so that the viewing surface is displaced from perpendicularity with the incident beam of the projected images by approximately 10 to 13 degrees, with the top of the viewing surface being farther away from the distal end of said lens system than is the bottom of the viewing surface, said viewing surface having an optical gain greater than approximately 13.

Claim 14

A projection system as recited in claim 11 wherein said viewing surface is tilted toward the projection system and is offset from the vertical by approximately 17 to 20 degrees.

Claim 15

A projection system as recited in claim 11 wherein said distal end is angularly displaced from horizontal by 30 degrees.

Claim 16

A projection system as recited in claim 11 wherein said lens system includes three Fresnel lenses.

Claim 17

A projection system as recited in claim 11 wherein said lens system further includes means for folding the lens system disposed between two of said Fresnel lenses.

Claim 18

A projection system as recited in claim 15 wherein said lens system folding means includes a mirror.

Claim 19

A projection system as recited in claim 16 wherein said mirror is disposed at substantially 45 degree with respect to two of said Fresnel lenses.

Claim 20

A projection system as recited in claim 17 wherein two of said Fresnel lenses are disposed near the proximal end of the lens system and one of the Fresnel lenses is disposed near the distal end of said lens system, said mirror being disposed between the Fresnel lens near the distal end of the system and the two Fresnel lenses disposed near the proximal end of the lens system.

Claim 21

A projection system as recited in claim 18 wherein said mirror operates as an aperture stop for the system.

Claim 22

A projection system as recited in claim 20 wherein the gain of said screen is substantially 17.

Claim 23

A projection system as recited in claim 11 wherein said lens system includes means for receiving images from a 13 inch diagonal measure cathode ray tube.

Claim 24

A projection video system comprising: a 13 inch diagonal measure image source; a viewing screen having an optical gain of greater than 13; and means including a lens system having a proximal end having a height of approximately 13 inches spaced approximately 5.7 inches from said image source optically interposed between said image source and said viewing screen for projecting images from said image source onto said viewing screen, said lens system having a focal length of substantially 280 mm and a horizontal beam angle at least approximately 20°.

Claim 25

A projection video system comprising: a 13 inch diagonal measure image source; a viewing screen having an optical gain of greater than 13; and means including a lens system having a proximal end having a height of approximately 13 inches spaced approximately 5.7 inches from said image source optically interposed between said image source and said viewing screen for projecting images from said image source onto said viewing screen, said lens system having a focal length of substantially 280 mm and a horizontal beam angle at least approximately 20°.

Claim 26

A projection video system as recited in claim 22 further including means for folding the lens system by substantially 90 degrees.

Claim 27

A projection video system as recited in claim 23 wherein said screen is offset from a perpendicular relationship with the incidence beam projected thereon by said lens system by approximately 10 to 13 degrees.

Claim 28

A projection video system as recited in claim 24 wherein said screen is offset from the vertical by approximately 17 to 20 degrees.

Claim 29

A projection video system as recited in claim 25 wherein the surface of the image source is angularly displaced from the horizontal by approximately 30 degrees.

Claim 30

A projection video system as recited in claim 26 wherein said image source is a cathode ray tube.

Claim 31

A projection video system as recited in claim 27 wherein said lens system has an aperture stop of approximately f/1.44.

Claim 32

A projection video system as recited in claim 28 wherein said folding means defines the aperture stop.

Claim 33

A projection video system as recited in claim 29 wherein said folding means includes a mirror.

Claim 34

A projection video system as recited in claim 23 wherein said lens system includes a plurality of Fresnel lens elements.

Claim 35

A projection video system as recited in claim 30 wherein said folding means is interposed between two of said Fresnel elements.

Claim 36

A projection video system as recited in claim 32 wherein said lens system includes three Fresnel elements.

Claim 37

A projection video system as recited in claim 33 wherein two of said Fresnel elements are interposed between said image source and said folding means.