Lenses for electronic imaging systems

• US 6,097,551 A
• Filed: 05/25/1999
• Issued: 08/01/2000
• Est. Priority Date: 11/29/1996
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: US Precision Lens, Inc. (3M Company)
• Inventors: Kreitzer, Melvyn H.
• Primary Examiner(s): Epps, Georgia
• Assistant Examiner(s): Spector, David N.
• Application Number:
  US09/308,798
• Time in Patent Office: 434 Days
• Field of Search: 359/793, 359/795, 359/709, 359/717, 359/648, 359/649, 359/651, 356/300, 356/301
• US Class Current: 359/793
• CPC Class Codes: G02B 13/04 Reversed telephoto objectives
• CPC Class Codes: G02B 27/0037 with diffracting elements G02B27/0056 takes precedence; holographic optical elements G02B5/32; zone systems G02B5/1876
• CPC Class Codes: G02B 27/4211 correcting chromatic aberrations G02B27/0056, G02B27/4222, G02B27/4227 take precedence
• CPC Class Codes: G02B 9/04 having two components only
• CPC Class Codes: G02B 9/10 one + and one - component

Abstract

A lens system for an electronic system has two lenses. The first lens (S1/S2) has a negative power, and the second lens (S4/S5 or S5/S6) has a positive power and is spaced from the first lens (S1/S2) by a distance of at least a quarter of the focal length of the lens system. In one embodiment (FIG. 3), the second lens (S4/S5) is a refractive-diffractive hybrid lens; in which case both the first and the second lenses (S1/S2 and S4/S5) can be composed of acrylic, and can have only spherical and conic surfaces. In other embodiments (FIG. 1, 2, 4), the first lens (S1/S2) has a higher dispersion than the than the second lens (S4/S5 or S5/S6); for example, the first lens (S1/S2) is composed of styrene, and the second lens (S4/S5 or S5/S6) is composed of acrylic. In this case, the first lens (S1/S2) can have a spherical surface and a general aspherical surface, and the second lens (S5/S6) can have conic surfaces (FIG. 1, 2); or both of the first and second lenses (S1/S2 and S4/S5) can have a spherical surface, and a conic surface (FIG. 4).

Claims

1. A lens system for forming an image of an object, said system having a focal length f₀ and consisting in order from its object side to its image side of:

(a) a first lens element having a focal length f₁ and a thickness t₁ ; and

(b) a second lens element having a focal length f₂, said second lens element being spaced from the first lens element by a distance d₁₂ ;

wherein;

space="preserve" listing-type="equation">f.sub.1 <

0;

space="preserve" listing-type="equation">|f.sub.1 |/f.sub.0 >

1.0;

space="preserve" listing-type="equation">t.sub.1 /f.sub.0 >

0.5;

space="preserve" listing-type="equation">f.sub.2 >

0; and

space="preserve" listing-type="equation">d.sub.12 /f.sub.0 >

0.25.

2. The lens system of claim 1 wherein:

space="preserve" listing-type="equation">|f.sub.1 |/f.sub.0 >

1.5;

space="preserve" listing-type="equation">t.sub.1 /f.sub.0 >

0.7; and

space="preserve" listing-type="equation">d.sub.12 /f.sub.0 >

0.5.

3. The lens system of claim 1 or 2 wherein:

space="preserve" listing-type="equation">f.sub.2 /f.sub.0 <

2.0.

4. The lens system of claim 3 wherein:

space="preserve" listing-type="equation">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 t₂ and wherein:

space="preserve" listing-type="equation">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:

space="preserve" listing-type="equation">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_EP, the first lens element has a diameter D₁, and the second lens element has a diameter D₂, where:

space="preserve" listing-type="equation">D.sub.1 /D.sub.EP >

2.5; and

space="preserve" listing-type="equation">D.sub.2 /D.sub.EP >

1.3.

17. The lens system of claim 16 wherein:

space="preserve" listing-type="equation">D.sub.1 /D.sub.EP >

3.0; and

space="preserve" listing-type="equation">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.

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.

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.

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.

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.

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.

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.

22. A lens system for forming an image of an object, said system having an entrance pupil whose diameter is D_EP and consisting in order from its object side to its image side of:

(a) a negative lens element having a diameter D₁ ; and

(b) a positive lens element having a diameter D_2;

wherein;

space="preserve" listing-type="equation">D.sub.1 /D.sub.EP >

2.5; and

space="preserve" listing-type="equation">D.sub.2 /D.sub.EP >

1.3.

23. The lens system of claim 22 where:

space="preserve" listing-type="equation">D.sub.1 /D.sub.EP >

3.0; and

space="preserve" listing-type="equation">D.sub.2 /D.sub.EP >

1.5.

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.