Claims
- 1. A lens system for forming an image of an object, said system having a focal length f.sub.0 and consisting in order from its object side to its image side of:
- (a) a first lens element having a focal length f.sub.1 and a thickness t.sub.1 ; and
- (b) a second lens element having a focal length f.sub.2, said second lens element being spaced from the first lens element by a distance d.sub.12 ;
- wherein:
- f.sub.1 <0;
- .vertline.f.sub.1 .vertline./f.sub.0 >1.0;
- t.sub.1 /f.sub.0 >0.5;
- f.sub.2 >0; and
- d.sub.12 /f.sub.0 >0.25.
- 2. The lens system of claim 1 wherein:
- .vertline.f.sub.1 .vertline./f.sub.0 >1.5;
- t.sub.1 /f.sub.0 >0.7; and
- d.sub.12 /f.sub.0 >0.5.
- 3. The lens system of claim 1 or 2 wherein:
- f.sub.2 /f.sub.0 <2.0.
- 4. The lens system of claim 3 wherein:
- f.sub.2 /f.sub.0 <1.6.
- 5. The lens system of claim 1 or 2 wherein the second lens element has a thickness t.sub.2 and wherein:
- t.sub.2 /f.sub.0 >0.5.
- 6.
- 6. The lens system of claim 1 or 2 wherein the first lens element has a higher dispersion than the second lens element.
- 7. The lens system of claim 6 wherein the first lens element is composed of styrene and the second lens element is composed of acrylic.
- 8. The lens system of claim 1 or 2 wherein the second lens element is a refractive-diffractive hybrid element.
- 9. The lens system of claim 8 wherein the first and second lens elements are composed of acrylic.
- 10. The lens system of claim 8 wherein:
- f.sub.2 /f.sub.0 >1.0.
- 11. The lens system of claim 1 wherein:
- (i) the first lens element has a spherical surface and a general aspherical surface; and
- (ii) the second lens element has two conic surfaces.
- 12. The lens system of claim 1 wherein:
- (i) the first lens element has a spherical surface and a conic surface; and
- (ii) the second lens element has two conic surfaces.
- 13. The lens system of claim 12 wherein the second lens element is a refractive-diffractive hybrid element.
- 14. The lens system of claim 1 wherein:
- (i) the first lens element has a spherical surface and a conic surface; and
- (ii) the second lens element has a spherical surface and a conic surface.
- 15. The lens system of claim 14 wherein the conic surface is on the object side of each of the first and second lens elements.
- 16. The lens system of claim 1 or 2 wherein the lens system has an entrance pupil whose diameter is D.sub.EP, the first lens element has a diameter D.sub.1, and the second lens element has a diameter D.sub.2, where:
- D.sub.1 /D.sub.EP >2.5; and
- D.sub.2 /D.sub.EP >1.3.
- 17. The lens system of claim 16 wherein:
- D.sub.1 /D.sub.EP >3.0; and
- D.sub.2 /D.sub.EP >1.5.
- 18. A lens system for forming an image of an object, said system consisting in order from its object side to its image side of:
- (a) a negative first lens element having a spherical surface and a general aspherical surface; and
- (b) a positive second lens element having two conic surfaces.
- 19. A lens system for forming an image of an object, said system consisting in order from its object side to its image side of:
- (a) a negative first lens element having a spherical surface and a conic surface; and
- (b) a positive second lens element having two conic surfaces.
- 20. The lens system of claim 19 wherein the second lens element is a refractive-diffractive hybrid element.
- 21. A lens system for forming an image of an object, said system consisting in order from its object side to its image side of:
- (a) a negative first lens element having a spherical surface and a conic surface; and
- (b) a positive second lens element having a spherical surface and a conic surface.
- 22. A lens system for forming an image of an object, said system having an entrance pupil whose diameter is D.sub.EP and consisting in order from its object side to its image side of:
- (a) a negative lens element having a diameter D.sub.1 ; and
- (b) a positive lens element having a diameter D.sub.2;
- wherein:
- D.sub.1 /D.sub.EP >2.5; and
- D.sub.2 /D.sub.EP >1.3.
- 23. The lens system of claim 22 where:
- D.sub.1 /D.sub.EP >3.0; and
- D.sub.2 /D.sub.EP >1.5.
- 24. An optical system comprising a lens system for forming an image of an object and an electronic imaging system for detecting said image, said lens system being the lens system of claim 1 or 2.
- 25. The optical system of claim 24 wherein the electronic imaging system is a charged coupled device.
- 26. An optical system comprising a lens system for forming an image of an object and an electronic imaging system for detecting said image, said lens system being the lens system of claim 18.
- 27. The optical system of claim 26 wherein the electronic imaging system is a charged coupled device.
- 28. An optical system comprising a lens system for forming an image of an object and an electronic imaging system for detecting said image, said lens system being the lens system of claim 19.
- 29. The optical system of claim 28 wherein the electronic imaging system is a charged coupled device.
- 30. An optical system comprising a lens system for forming an image of an object and an electronic imaging system for detecting said image, said lens system being the lens system of claim 21.
- 31. The optical system of claim 30 wherein the electronic imaging system is a charged coupled device.
- 32. An optical system comprising a lens system for forming an image of an object and an electronic imaging system for detecting said image, said lens system being the lens system of claim 22 or 23.
- 33. The optical system of claim 32 wherein the electronic imaging system is a charged coupled device.
CROSS REFERENCE TO RELATED APPLICATION
This application is the U.S. national phase of International Application No. PCT/US97/20144, filed Nov. 12, 1997, and claims the benefit under 35 USC .sctn.119(e) of the U.S. Provisional Application No. 60/033,348, filed Nov. 29, 1996, the contents of each of which in their entireties are hereby incorporated by reference.
PCT Information
Filing Document |
Filing Date |
Country |
Kind |
102e Date |
371c Date |
PCT/US97/20144 |
11/12/1997 |
|
|
5/25/1999 |
5/25/1999 |
Publishing Document |
Publishing Date |
Country |
Kind |
WO98/23988 |
6/4/1998 |
|
|
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
5677798 |
Hirano et al. |
Oct 1997 |
|