G - Physics – 02 – B
Patent
G - Physics
02
B
88/99
G02B 13/18 (2006.01) G02B 13/16 (2006.01)
Patent
CA 1261180
ABSTRACT : PROJECTION LENS SYSTEM. A lens system is provided which is suitable for back- projecting an enlarged image of a TV cathode ray tube (CRT). To achieve a compact cabinet design 1 for such a projection angle are required, together with a wide aperture (F/1) for a bright projected picture and with a definition which may need to be good enough to resolve 1249 line television pictures. The lens system comprises a CRT face plate FP which is either flat or has a relatively shallow curvature on one or both sides and four lens elements L1, L2, L3 and L4. L1 is a weak lens, L2 and L3 are each of positive power and L4 is a negative element close to the CRT. At least two of the element surfaces are aspheric. The powers of the elements are chosen so that -0.20K < K1 < +0.10K +0.60K < K2 < +0.85K +0.35K < K3 < +0.55K -1.20K < K4 < -0.90K where K1 is the power of the first low power element remote from the object surface, K2 is the power of the second element, K3 is the power of the third element and K4 the power of the fourth element close to the CRT surface and K is the total power of the projection lens. Projection angles up to ? 35 degrees are obtained. (Figures 1 and 2).
497498
Fetherstonhaugh & Co.
Koninklijke Philips Electronics N.v.
LandOfFree
Projection lens system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Projection lens system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Projection lens system will most certainly appreciate the feedback.
Profile ID: LFCA-PAI-O-1233130