H - Electricity – 04 – N
Patent
H - Electricity
04
N
88/52, 350/98
H04N 5/74 (2006.01) H04N 9/31 (2006.01)
Patent
CA 1167297
Abstract of the Disclosure A projection television system having three differ- ent primary color picture tubes in an in-line configuration, one centrally located on the projection screen axis and the other two on opposite sides of the axis. In order to compen- sate for the defocussing which these off-axis locations pro- duce at the edges of the projected image, the off-axis pic- ture tubes are rotated relative to the optical axes of their respective focussing lenses, thus rotating the correspond- ing projected images into coincidence with the projection screen. The off-axis positioning also produces color shad- ing by making the square law fall-off in illumination vary across the projection screen, and also by producing a trape- zoidal distortion which is compensated by pre-distortion which introduces additional color shading effects. The first effect is reduced by making the lenses tangent or nearly tangent to each other, thus minimizing the angular deviation of the projection axes. The second effect results from the use of slanted CRT electron guns to achieve the compensa- tory trapezoidal pre-distortion of the off-axis object images, and is corrected by laterally offsetting these object images (CRT rasters) from the optical axes of their focus- sing lenses. This off-set can be achieved by laterally dis- placing the entire picture tube, or by laterally displacing the electron gun relative to the tube faceplate, or by magnetically deflecting the electron beam. The degree of offset is preferably such as to equalize the distances of all object image corner points from the lens axis. The offset then must itself be compensated by rotating the off-axis lenses so that their optical axes are underconverged.
401101
Macrae & Co.
Zenith Radio Corporation
LandOfFree
Color projection tv systems does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Color projection tv systems, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Color projection tv systems will most certainly appreciate the feedback.
Profile ID: LFCA-PAI-O-1179201