Impaired vision assist system and method

• US 20030169491A1
• Filed: 05/12/2003
• Published: 09/11/2003
• Est. Priority Date: 07/10/2000
• Status: Abandoned Application

• Current Assignee: Ophir Optronics Ltd. (MKS Instruments Incorporated)
• Original Assignee: Ophir Optronics Ltd. (MKS Instruments Incorporated)
• Inventors: Asida, Nissim, Bender, Eliyahu
• Application Number:
  US10/332,603
• Publication Number:
  US 20030169491A1
• Time in Patent Office: Days
• US Class Current: 359/356
• CPC Class Codes: G02B 2027/0138 comprising image capture systems, e.g. camera
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: H04N 23/20 for generating image signals from infrared radiation only
• CPC Class Codes: H04N 5/33 Transforming infrared radiation cameras or camera modules for generating image signals from infrared radiation H04N23/20; circuitry of SSIS for transforming infrared radiation into image signals H04N25/20

Abstract

A night vision system, suitable for vehicular use, including an infra-red detector mounted on a vehicle, a display mounted on the vehicle, a single-element lens mounted upstream of the infra-red detector so as to direct light from a scene onto the infra-red detector, and circuitry operative to receive a detector output from the infra-red detector and to provide an image output based on the detector output to the display. The system is suitable for applications other than vehicular use, where a comparatively narrow field of view is to be imaged.

Claims

1. A vehicular night vision system comprising:

an infra-red detector mounted on a vehicle;

a display mounted on said vehicle;

a focusing assembly for directing infrared radiation from a scene onto said infra-red detector, comprising a single-element lens, mounted upstream of said infra-red detector; and

circuitry operative to receive a detector output from said infra-red detector and to provide an image output based on said detector output to said display.

2. A vehicular night vision system according to claim 1 and wherein said single-element lens and said infra-red detector are mounted in a housing and together define an infra-red camera which is mounted by means of said housing on said vehicle in a forward looking orientation.

3. A vehicular night vision system according to claim 1 and wherein said display is a transparent display mounted on said vehicle so as to overlie at least a portion of a vehicle windshield.

4. A vehicular night vision system according to claim 2 and wherein said display is a transparent display mounted on said vehicle so as to overlie at least a portion of a vehicle windshield.

5. A vehicular night vision system according to claim 1 and wherein no optical element having optical power is interposed between said single-element lens and said scene.

6. A vehicular night vision system according to claim 2 and wherein said camera includes an aperture stop which is distanced forwardly of a front facing surface of said single-element lens by a distance which exceeds the focal length of said single-element lens.

7. A vehicular night vision system according to claim 2 and wherein said camera includes an aperture stop which is distanced forwardly of a front facing surface of said single-element lens by a distance which exceeds twice the focal length of said single-element lens.

8. A vehicular night vision system according to claim 4 and wherein said camera includes an aperture stop which is distanced forwardly of a front facing surface of said single-element lens by a distance which exceeds the focal length of said single-element lens.

9. A vehicular night vision system according to claim 4 and wherein said camera includes an aperture stop which is distanced forwardly of a front facing surface of said single-element lens by a distance which exceeds twice the focal length of said single-element lens.

10. A vehicular night vision system according to claim 8 and wherein no optical element having optical power is interposed between said single-element lens and said scene.

22. A night vision system according to claim 1 and wherein said single-element lens and said infra-red detector are mounted in a housing and together define an infra-red camera.

26. A night vision system according to claim 22 and wherein said camera includes an aperture stop which is distanced forwardly of a front facing surface of said single-element lens by a distance which exceeds the focal length of said single-element lens.

27. A night vision system according to claim 22 and wherein said camera includes an aperture stop which is distanced forwardly of a front facing surface of said single-element lens by a distance which exceeds twice the focal length of said single-element lens.

41. A vehicular night vision system according to claim 2 and wherein said camera includes an aperture stop which is distanced rearwardly of the center of a front facing surface of said single-element lens by a distance which is less than the focal length of said single-element lens.

42. A vehicular night vision system according to claim 4 and wherein said camera includes an aperture stop which is distanced rearwardly of the center of a front facing surface of said single-element lens by a distance which is less than the focal length of single-element lens.

45. A night vision system according to claim 22 and wherein said camera includes an aperture stop which is distanced rearwardly of the center of a front facing surface of said single-element lens by a distance which is less than the focal length of single-element lens.

49. A vehicular night vision system according to claim 1 and wherein said single element lens satisfies the following conditions:

5°

<

FOV<

60°

 

 

(1) 0.5<

F<

4 

 

(2) 0.7f<

r1<

3.1f 

 

(3) f<

r2<

infinity 

 

(4) 1.4<

n<

4.5 

 

(5) 0.4f<

bf<

f 

 

(6) 0.05f<

t<

f 

 

(7)

where;

f is the focal length;

F is the f-number;

FOV is the field of view;

r1 is the radius of curvature of the front-facing convex surface of the lens;

r2 is the radius of curvature of the rear-facing surface of the lens;

n is the refractive index of the lens material at a wavelength near the center of the spectral range being imaged;

bf is the back focal length between the center of the rear-facing surface of the lens and the Gaussian image plane;

t is the center thickness of the lens.

50. A vehicular night vision system according to claim 1 and wherein said single element lens satisfies the following conditions:

8°

<

FOV<

35°

 

 

(1) 0.7<

F<

2.8 

 

(2) 0.7f<

r1<

3.1f 

 

(3) f<

r2<

infinity 

 

(4) 2<

n<

4.5 

 

(5) 0.7f<

bf<

f 

 

(6) 0.05f<

t<

0.3f 

 

(7) −

0.1f<

d<

10f 

 

(8)

where;

f is the focal length;

F is the f-number;

FOV is the field of view;

r1 is the radius of curvature of the front-facing convex surface of the lens;

r2 is the radius of curvature of the rear-facing surface of the lens;

n is the refractive index of the lens material at a wavelength near the center of the spectral range being imaged;

bf is the back focal length between the center of the rear-facing surface of the lens and the Gaussian image plane;

t is the center thickness of the lens;

d is the position of the stop relative to the center of the front-facing surface of the lens wherein a positive value means that the stop is forward of the lens and a negative value means that the stop is behind the center of the front-facing surface of the lens.

51. A vehicular night vision system according to claim 1 and wherein said single element lens satisfies the following conditions:

8°

<

FOV<

35°

 

 

(1) 0.7<

F<

2.8 

 

(2) 0.7f<

r1<

3.1f 

 

(3) f<

r2<

infinity 

 

(4) 2<

n<

4.5 

 

(5) 0.7f<

bf<

f 

 

(6) 0.05f<

t<

0.3f 

 

(7) 0.7f<

d<

10f 

 

(8)

where;

f is the focal length;

F is the f-number;

FOV is the field of view;

r1 is the radius of curvature of the front-facing convex surface of the lens;

r2 is the radius of curvature of the rear-facing surface of the lens;

n is the refractive index of the lens material at a wavelength near the center of the spectral range being imaged;

bf is the back focal length between the center of the rear-facing surface of the lens and the Gaussian image plane;

t is the center thickness of the lens;

d is the position of the stop relative to the center of the front-facing surface of the lens wherein a positive value means that the stop is forward of the lens and a negative value means that the stop is behind the center of the front-facing surface of the lens.

61. A vehicular night vision system according to claim 1 and wherein said single element lens has at least one surface aspheric.

62. A vehicular night vision system according to claim 1 and wherein said single element lens has both surfaces aspheric.

63. A vehicular night vision system according to claim 1 and wherein said single element lens comprises a diffractive optical profile on at least one of its surfaces.

11. A vehicle having night vision functionality comprising:

a motor vehicle;

an infrared detector mounted on said vehicle;

a display mounted on said vehicle;

a focusing assembly for directing infrared radiation from a scene onto said infra-red detector, comprising a single-element lens only, mounted upstream of said infra-red detector; and

circuitry operative to receive a detector output from said infrared detector and to provide an image output based on said detector output to said display.

12. A vehicle having night vision functionality according to claim 11 and wherein said single-element lens and said infra-red detector are mounted in a housing and together define an infra-red camera which is mounted by means of said housing on said vehicle in a forward looking orientation.

13. A vehicle having night vision functionality according to claim 11 and wherein said display is a transparent display mounted on said vehicle so as to overlie at least a portion of a vehicle windshield.

14. A vehicle having night vision functionality according to claim 12 and wherein said display is a transparent display mounted on said vehicle so as to overlie at least a portion of a vehicle windshield.

15. A vehicle having night vision functionality according to claim 11 and wherein no optical element having optical power is interposed between said single-element lens and said scene.

16. A vehicle having night vision functionality according to claim 12 and wherein said camera includes an aperture stop which is distanced forwardly of a front facing surface of said single-element lens by a distance which exceeds the focal length of said single-element lens.

17. A vehicle having night vision functionality according to claim 12 and wherein said camera includes an aperture stop which is distanced forwardly of a front facing surface of said single-element lens by a distance which exceeds twice the focal length of said single-element lens.

18. A vehicle having night vision functionality according to claim 14 and wherein said camera includes an aperture stop which is distanced forwardly of a front facing surface of said single-element lens by a distance which exceeds the focal length of said single-element lens.

19. A vehicle having night vision functionality according to claim 14 and wherein said camera includes an aperture stop which is distanced forwardly of a front facing surface of said single-element lens by a distance which exceeds twice the focal length of said single-element lens.

20. A vehicle having night vision functionality according to claim 18 and wherein no optical element having optical power is interposed between said single-element lens and said scene.

43. A vehicle having night vision functionality according to claim 12 and wherein said camera includes an aperture stop which is distanced rearwardly of the center of a front facing surface of said single-element lens by a distance which is less than the focal length of single-element lens.

44. A vehicle having night vision functionality according to claim 14 and wherein said camera includes an aperture stop which is distanced rearwardly of the center of a front facing surface of said single-element lens by a distance which is less than the focal length of single-element lens.

52. A vehicle having night vision functionality according to claim 11 and wherein said single element lens satisfies the following conditions:

5°

<

FOV<

60°

 

 

(1) 0.5<

F<

4 

 

(2) 0.7f<

r1<

3.1f 

 

(3) f<

r2<

infinity 

 

(4) 1.4<

n<

4.5 

 

(5) 0.4f<

bf<

f 

 

(6) 0.05f<

t<

f<

 

 

(7)

where;

f is the focal length;

F is the f-number;

FOV is the field of view;

r1 is the radius of curvature of the front-facing convex surface of the lens;

r2 is the radius of curvature of the rear-facing surface of the lens;

n is the refractive index of the lens material at a wavelength near the center of the spectral range being imaged;

bf is the back focal length between the center of the rear-facing surface of the lens and the Gaussian image plane;

t is the center thickness of the lens.

53. A vehicle having night vision functionality according to claim 11 and wherein said single element lens satisfies the following conditions:

8°

<

FOV<

35°

 

 

(1) 0.7<

F<

2.8 

 

(2) 0.7f<

r1<

3.1f 

 

(3) f<

r2<

infinity 

 

(4) 2<

n<

4.5 

 

(5) 0.7f<

bf<

f 

 

(6) 0.05f<

t<

0.3f 

 

(7) −

0.1f<

d<

10f 

 

(8)

where;

f is the focal length;

F is the f-number;

FOV is the field of view;

r1 is the radius of curvature of the front-facing convex surface of the lens;

r2 is the radius of curvature of the rear-facing surface of the lens;

n is the refractive index of the lens material at a wavelength near the center of the spectral range being imaged;

bf is the back focal length between the center of the rear-facing surface of the lens and the Gaussian image plane;

t is the center thickness of the lens;

d is the position of the stop relative to the center of the front-facing surface of the lens wherein a positive value means that the stop is forward of the lens and a negative value means that the stop is behind the center of the front-facing surface of the lens.

54. A vehicle having night vision functionality according to claim 11 and wherein said single element lens satisfies the following conditions:

8°

<

FOV<

35°

 

 

(1) 0.7<

F<

2.8 

 

(2) 0.7f<

r1<

3.1f 

 

(3) f<

r2<

infinity 

 

(4) 2<

n<

4.5 

 

(5) 0.7f<

bf<

f 

 

(6) 0.05f<

t<

0.3f 

 

(7) 0.7f<

d<

10f 

 

(8)

where;

f is the focal length;

F is the f-number;

FOV is the field of view;

r1 is the radius of curvature of the front-facing convex surface of the lens;

r2 is the radius of curvature of the rear-facing surface of the lens;

n is the refractive index of the lens material at a wavelength near the center of the spectral range being imaged;

bf is the back focal length between the center of the rear-facing surface of the lens and the Gaussian image plane;

t is the center thickness of the lens;

d is the position of the stop relative to the center of the front-facing surface of the lens wherein a positive value means that the stop is forward of the lens and a negative value means that the stop is behind the center of the front-facing surface of the lens.

64. A vehicle having night vision functionality according to claim 11 and wherein said single element lens has at least one surface aspheric.

65. A vehicle having night vision functionality according to claim 11 and wherein said single element lens has both surfaces aspheric.

66. A vehicle having night vision functionality according to claim 11 and wherein said single element lens comprises a diffractive optical profile on at least one of its surfaces.

21. A night vision system comprising:

an infra-red detector;

a display;

a focusing assembly for directing infrared radiation from a scene onto said infra-red detector, comprising a single-element lens only, mounted upstream of said infra-red detector; and

circuitry operative to receive a detector output from said infrared detector and to provide an image output based on said detector output to said display.

23. A night vision system according to claim 21 and wherein said display is a transparent display.

24. A night vision system according to claim 21 and wherein said display is a flat panel display.

25. A night vision system according to claim 21 and wherein no optical element having optical power is interposed between said single-element lens and said scene.

28. A night vision system according to claim 24 and wherein said camera includes an aperture stop which is distanced forwardly of a front facing surface of said single-element lens by a distance which exceeds the focal length of said single-element lens.

29. A night vision system according to claim 24 and wherein said camera includes an aperture stop which is distanced forwardly of a front facing surface of said single-element lens by a distance which exceeds twice the focal length of said single-element lens.

30. A night vision system according to claim 28 and wherein no optical element having optical power is interposed between said single-element lens and said scene.

46. A night vision system according to claim 24 and wherein said camera includes an aperture stop which is distanced rearwardly of the center of a front facing surface of said single-element lens by a distance which is less than the focal length of single-element lens.

55. A night vision system according to claim 21 and wherein said single element lens satisfies the following conditions:

5°

<

FOV<

60°

 

 

(1) 0.5<

F<

4 

 

(2) 0.7f<

r1<

3.1f 

 

(3) f<

r2<

infinity 

 

(4) 1.4<

n<

4.5 

 

(5) 0.4f<

bf<

f 

 

(6) 0.05f<

t<

f 

 

(7)

where;

f is the focal length;

F is the f-number;

FOV is the field of view;

r1 is the radius of curvature of the front-facing convex surface of the lens;

r2 is the radius of curvature of the rear-facing surface of the lens;

n is the refractive index of the lens material at a wavelength near the center of the spectral range being imaged;

bf is the back focal length between the center of the rear-facing surface of the lens and the Gaussian image plane;

t is the center thickness of the lens.

56. A night vision system according to claim 21 and wherein said single element lens satisfies the following conditions:

8°

<

FOV<

35°

 

 

(1) 0.7<

F<

2.8 

 

(2) 0.7f<

r1<

3.1f 

 

(3) f<

r2<

infinity 

 

(4) 2<

n<

4.5 

 

(5) 0.7f<

bf<

f 

 

(6) 0.05f<

t<

0.3f 

 

(7) −

0.1f<

d<

10f 

 

(8)

where;

f is the focal length;

F is the f-number;

FOV is the field of view;

r1 is the radius of curvature of the front-facing convex surface of the lens;

r2 is the radius of curvature of the rear-facing surface of the lens;

n is the refractive index of the lens material at a wavelength near the center of the spectral range being imaged;

bf is the back focal length between the center of the rear-facing surface of the lens and the Gaussian image plane;

t is the center thickness of the lens;

d is the position of the stop relative to the center of the front-facing surface of the lens wherein a positive value means that the stop is forward of the lens and a negative value means that the stop is behind the center of the front-facing surface of the lens.

57. A night vision system according to claim 21 and wherein said single element lens satisfies the following conditions:

8°

<

FOV<

35°

 

 

(1) 0.7<

F<

2.8 

 

(2) 0.7f<

r1<

3.1f 

 

(3) f<

r2<

infinity 

 

(4) 2<

n<

4.5 

 

(5) 0.7f<

bf<

f 

 

(6) 0.05f<

t<

0.3f 

 

(7) 0.7f<

d<

10f 

 

(8)

where;

f is the focal length;

F is the f-number;

FOV is the field of view;

r1 is the radius of curvature of the front-facing convex surface of the lens;

r2 is the radius of curvature of the rear-facing surface of the lens;

n is the refractive index of the lens material at a wavelength near the center of the spectral range being imaged;

bf is the back focal length between the center of the rear-facing surface of the lens and the Gaussian image plane;

t is the center thickness of the lens;

d is the position of the stop relative to the center of the front-facing surface of the lens wherein a positive value means that the stop is forward of the lens and a negative value means that the stop is behind the center of the front-facing surface of the lens.

67. A night vision system according to claim 21 and wherein said single element lens has at least one surface aspheric.

68. A night vision system according to claim 21 and wherein said single element lens has both surfaces aspheric.

69. A night vision system according to claim 21 and wherein said single element lens comprises a diffractive optical profile on at least one of its surfaces.

31. A vehicular night vision method comprising the steps of:

mounting an infrared detector on a vehicle;

mounting a display on said vehicle;

providing a focusing assembly for directing infrared radiation from a scene onto said infra-red detector, comprising a single-element lens only, mounted upstream of said infra-red detector; and

receiving a detector output from said infrared detector and providing an image output based on said detector output to said display.

32. A vehicular night vision method according to claim 31 and wherein said single-element lens and said infra-red detector are mounted in a housing and together define an infra-red camera which is mounted by means of said housing on said vehicle in a forward looking orientation.

33. A vehicular night vision method according to claim 31 and wherein said display is a transparent display mounted on said vehicle so as to overlie at least a portion of said vehicle windshield.

34. A vehicular night vision method according to claim 32 and wherein said display is a transparent display mounted on said vehicle so as to overlie at least a portion of said vehicle windshield.

35. A vehicular night vision method according to claim 31 and wherein no optical element having optical power is interposed between said single-element lens and said scene.

36. A vehicular night vision method according to claim 32 and wherein said camera includes an aperture stop which is distanced forwardly of a front facing surface of said single-element lens by a distance which exceeds the focal length of said single-element lens.

37. A vehicular night vision method according to claim 32 and wherein said camera includes an aperture stop which is distanced forwardly of a front facing surface of said single-element lens by a distance which exceeds twice the focal length of said single-element lens.

38. A vehicular night vision method according to claim 34 and wherein said camera includes an aperture stop which is distanced forwardly of a front facing surface of said single-element lens by a distance which exceeds the focal length of said single-element lens.

39. A vehicular night vision method according to claim 34 and wherein said camera includes an aperture stop which is distanced forwardly of a front facing surface of said single-element lens by a distance which exceeds twice the focal length of said single-element lens.

40. A vehicular night vision method according to claim 38 and wherein no optical element having optical power is interposed between said single-element lens and said scene.

47. A vehicular night vision method according to claim 32 and wherein said camera includes an aperture stop which is distanced rearwardly of the center of a front facing surface of said single-element lens by a distance which is less than the focal length of single-element lens.

48. A vehicular night vision method according to claim 34 and wherein said camera includes an aperture stop which is distanced rearwardly of the center of a front facing surface of said single-element lens by a distance which is less than the focal length of single-element lens.

58. A vehicular night vision method according to claim 31 and wherein said single element lens satisfies the following conditions:

5°

<

FOV<

60°

 

 

(1) 0.5<

F<

4 

 

(2) 0.7f<

r1<

3.1f 

 

(3) f<

r2<

infinity 

 

(4) 1.4<

n<

4.5 

 

(5) 0.4f<

bf<

f 

 

(6) 0.05f<

t<

f 

 

(7)

where;

f is the focal length;

F is the f-number;

FOV is the field of view;

r1 is the radius of curvature of the front-facing convex surface of the lens;

r2 is the radius of curvature of the rear-facing surface of the lens;

n is the refractive index of the lens material at a wavelength near the center of the spectral range being imaged;

bf is the back focal length between the center of the rear-facing surface of the lens and the Gaussian image plane;

t is the center thickness of the lens.

59. A vehicular night vision method according to claim 31 and wherein said single element lens satisfies the following conditions:

8°

<

FOV<

35°

 

 

(1) 0.7<

F<

2.8 

 

(2) 0.7f<

r1<

3.1f 

 

(3) f<

r2<

infinity 

 

(4) 2<

n<

4.5 

 

(5) 0.7f<

bf<

f 

 

(6) 0.05f<

t<

0.3f 

 

(7) −

0.1f<

d<

10f 

 

(8)

where;

f is the focal length;

F is the f-number;

FOV is the field of view;

r1 is the radius of curvature of the front-facing convex surface of the lens;

r2 is the radius of curvature of the rear-facing surface of the lens;

n is the refractive index of the lens material at a wavelength near the center of the spectral range being imaged;

bf is the back focal length between the center of the rear-facing surface of the lens and the Gaussian image plane;

t is the center thickness of the lens;

d is the position of the stop relative to the center of the front-facing surface of the lens wherein a positive value means that the stop is forward of the lens and a negative value means that the stop is behind the center of the front-facing surface of the lens.

60. A vehicular night vision method according to claim 31 and wherein said single element lens satisfies the following conditions:

8°

<

FOV<

35°

 

 

(1) 0.7<

F<

2.8 

 

(2) 0.7f<

r1<

3.1f 

 

(3) f<

r2<

infinity 

 

(4) 2<

n<

4.5 

 

(5) 0.7f<

bf<

f 

 

(6) 0.05f<

t<

0.3f 

 

(7) 0.7f<

d<

10f 

 

(8)

where;

f is the focal length;

F is the f-number;

FOV is the field of view;

r1 is the radius of curvature of the front-facing convex surface of the lens;

r2 is the radius of curvature of the rear-facing surface of the lens;

n is the refractive index of the lens material at a wavelength near the center of the spectral range being imaged;

bf is the back focal length between the center of the rear-facing surface of the lens and the Gaussian image plane;

t is the center thickness of the lens;

d is the position of the stop relative to the center of the front-facing surface of the lens wherein a positive value means that the stop is forward of the lens and a negative value means that the stop is behind the center of the front-facing surface of the lens.

70. A vehicular night vision method according to claim 31 and wherein said single element lens has at least one surface aspheric.

71. A vehicular night vision method according to claim 31 and wherein said single element lens has both surfaces aspheric.

72. A vehicular night vision method according to claim 31 and wherein said single element lens comprises a diffractive optical profile on at least one of its surfaces.