Lens system

• US 5,808,815 A
• Filed: 12/22/1995
• Issued: 09/15/1998
• Est. Priority Date: 12/22/1995
• Status: Expired due to Fees

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Kouthoofd, Barbara J.
• Primary Examiner(s): Sugarman, Scott J.
• Application Number:
  US08/577,022
• Time in Patent Office: 998 Days
• Field of Search: 359/772, 359/773, 359/774, 359/775, 359/765, 359/766
• US Class Current: 359/772
• CPC Class Codes: G02B 13/24 for reproducing or copying at short object distances
• CPC Class Codes: G02B 9/34 having four components only

Abstract

A lens system comprises, in order from a first side to a second side four lens elements. They are: a first, positive power lens element having its convex surface oriented towards the first side; a second, negative power lens element; a third, meniscus lens element having its concave surface oriented towards the first side; and a fourth, meniscus lens element having its concave surface oriented towards the second side.

Claims

1. A lens system comprising in order from a first side to a second side:

(a) a first, positive power lens component having its convex surface oriented towards the second side;

(b) a second, negative power lens component;

(c) a third, meniscus lens component having an optical power and a concave surface oriented towards the first side; and

(d) a fourth, meniscus lens component having an optical power and a concave surface oriented towards the second side, the lens system characterized in that combined optical power of said third and fourth lens components is negative, and wherein there are no positive power lens components located between said second negative power lens component and said third meniscus lens component and between said third and said fourth meniscus lens components.

2. A lens system according to claim 1 wherein said first lens component is biconvex.

3. A lens system according to claim 1 wherein said second lens component is a meniscus lens component.

4. A lens system according to claim 1 wherein said first lens component is biconvex and said second lens component is a meniscus lens component.

5. A lens system comprising in order from a first side to a second side:

(a) a first, positive power lens component having its convex surface oriented towards the second side;

(b) a second, negative power lens component;

(c) a third, meniscus lens component having an optical power and a concave surface oriented towards the first side; and

(d) a fourth, meniscus lens component having an optical power and a concave surface oriented towards the second side, the lens system characterized in that (i) combined optical power of said third and fourth lens components is negative and (ii) said third and said fourth lens components are identical.

6. A lens system according to claim 5 wherein said third and said fourth meniscus lens components have negative optical power, respectively.

7. A lens system comprising in order from a first side to a second side:

(a) a first, positive power lens component having its convex surface oriented towards the second side;

(b) a second, negative power lens component;

(c) a third, meniscus lens component having an optical power and a concave surface oriented towards the first side; and

(d) a fourth, meniscus lens component having an optical power and a concave surface oriented towards the second side, the lens system characterized in that combined optical power of said third and fourth lens components is negative, and wherein said third and said fourth lens components are identical.

8. A lens system comprising in order from its long conjugate side to its short conjugate side:

(a) a first, positive power lens component having its convex surface oriented towards the short conjugate side;

(b) a second, negative power lens component;

(c) a third, meniscus lens component having an optical power and a concave surface oriented towards the long conjugate side; and

(d) a fourth, meniscus lens component having an optical power and a concave surface oriented towards the short conjugate side, the lens system characterized in that the absolute value of the combined optical power of said third and fourth lens components is less than one fifth of the power of said first, positive power lens component.

9. A lens system according to claim 8 wherein said combined optical power of said third and fourth lens components is less than 15% of the power of said first, positive power lens component.

10. A lens system according to claim 9 wherein said third and said fourth, lens components have negative optical power, respectively.

11. A lens system according to claim 10 wherein said third and said fourth lens components are identical.

12. A lens system according to claim 8 wherein said combined optical power of said third and fourth lens components is about one tenth or less than the power of said first, positive power lens component.

13. A lens system according to claim 8 wherein said third and said fourth lens components have negative optical power, respectively.

14. A lens system according to claim 13 wherein said third and said fourth lens components are identical.

15. A lens system according to claim 8 wherein said first lens component is biconvex and said second lens component is a meniscus lens component.

16. A lens claim according to claim 8 wherein said third and said fourth lens components are identical.

17. A lens system according to claim 16 wherein said first lens component is biconvex and said second lens component is a meniscus lens component.

18. A lens system consists in order from a first side to a second side:

(a) a first, positive power lens element having its convex surface oriented towards the second side;

(b) a second, negative power lens element;

(c) a third, meniscus lens element having an optical power and a concave surface oriented towards the first side; and

(d) a fourth, meniscus lens element having an optical power and a concave surface oriented towards the second side, the lens system characterized in that combined optical power of said third and fourth lens elements is negative.

19. A lens system according to claim 18 wherein said third and said fourth meniscus lens elements have negative optical power respectively.

20. A lens system consists in order from its long conjugate side to its short conjugate side:

(a) a first, positive power lens element having its convex surface oriented towards the short conjugate side;

(b) a second, negative power lens element;

(c) a third, meniscus lens element having an optical power and a concave surface oriented towards the long conjugate side; and

(d) a fourth, meniscus lens element having an optical power and a concave surface oriented towards the short conjugate side, the lens system characterized in that combined optical power of said third and fourth lens elements is less than one fifth of the power of said first, positive power lens element.

21. A lens system according to claim 20 wherein said third and said fourth meniscus lens elements have negative optical power respectively.