Back to results
US 6,445,512 B1Granted
Projection television lens systems having improved modulation transfer functions
AssigneeU.S. Precision Lens Incorporated
InventorJacob Moskovich
Life of this patent
Estimating the term…
Abstract
Six-component projection lens systems (13) for use in CRT projection televisions (10) are provided. To provide an improved overall modulation transfer function across the field of view of the lens, the system's first lens element (L1) has an object side surface (S2) which has a best fit spherical surface which is convex to the CRT (16). To provide partial axial color correction, the system's second lens element (L2) is made of a high dispersion material, such as styrene.
Claims11
A projection lens system for use with a cathode ray tube comprising in order from the image side:
- (a) a first lens element which has a positive power, an image side surface, and an object side surface, wherein:
- (i) at least one of the image and object side surfaces is aspherical;
- and
- (ii) the object side surface has a best fit spherical surface which is convex to the cathode ray tube;
- (b) a second lens element which has a negative power, at least one aspheric surface, and is composed of a high dispersion material;
- (c) a third lens element which has a positive power and provides a substantial portion of the power of the lens system;
- (d) a fourth lens element which has a weak power, at least one aspheric surface, and an overall meniscus shape which is concave to the cathode ray tube;
- (e) a fifth lens element which has a positive power and at least one aspheric surface;
- and
- (f) a lens unit which has a strong negative power, is associated with the CRT during use of the lens system, and provides most of the correction for the field curvature of the lens system.
7 more elements
Dependencies are inferred from the claim text.