Title: Photoelectric transducing unit and system for detecting the sharpness of the image of object by means of the unit

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Claims: What is claimed is:

1. A light-to-electrical signal conversion unit, comprising;

electrical insulation means permitting the passage of light therethrough,

first photoelectric transducing means including;

a pair of strip-shaped electrode members each having two long edges and two short edges smaller than the long edges, each of said electrode members being disposed over an area of said insulating means so that the member never crosses itself, one of the short edges of each member being disposed near the center of the area, said members being bifilar wound relative to each other over the area, the other short edge on each member being disposed at the outside of the area,

a first photosensitive element disposed between said bifilar wound members,

second photoelectric transducing means disposed on said insulating means over a second area opposing the first photoelectric transducing means, said second photoelectric transducing means including;

a belt-shaped second photosensitive element having two long edges and two short edges smaller than the long edges, said long edges having central portions, said element being folded so that the central portions are situated nearly at the center of the second area and being wound bifilarly over the second area similarly to said first photoelectic transducing means, the shorted edges being situated outside of the second area,

a pair of electrode pieces, each of said pieces being connected to each of said shorter edges.

2. A unit according to claim 1, in which said photosensitive element of said second photoelectric transducing means overlies said pair of the electrode members of said first photoelectric transducing means but lies wholly between said photosensitive element of said first photoelectric transducing means except at the center of the first area between short edges of said pair of the electrode member of said first photoelectric transducing means.

3. A unit according to claim 2, in which said first photoelectric tranducing means includes first holding means for holding said first photosensitive element while said second photoelectric transducing means includes the second holding means for holding the second photosensitive element, said holding means each having a surface opposing said insulating means, the photosensitive elements in said first and said second photoelectric transducing means being respectively disposed on the surface opposed to said insulation means.

4. A unit according to claim 3, in which said second holding means permits the passage of the light while said first holding means prevents the the light beam from influencing said photosensitive element of said second photoelectric transducing means from a surface reversed to the surface opposed to said insulation means.

5. A unit according to claim 4, in which at least one of said photosensitive elements of said first and said second photoelectric transducing means is formed of CdS.

6. A unit according to claim 5, in which at least one of said photosensitive elements of said first and said second photoelectric transducing means is vapor deposited on said holding means.

7. A unit according to claim 4, in which said electrode members of said first photoelectric transducing means are vapor deposited on said holding means.

8. A unit according to claim 1, in which said insulation means contains adhesive means.

9. A unit according to claim 1, in which at least one of said first photosensitive elements and of said second photosensitive elements permits passage of light.

10. A unit according to claim 9, in which said said second photosensitive elements permits the passage of light and overlies said pair of said electrode pieces of said first photoelectric transducing means but to overlap only said photoelectric semiconductor of said first photosensitive elements.

11. A unit according to claim 10, in which said first photosensitive elements permits the passage of light.

12. A unit according to claim 10, in which said unit is formed so that when light entering said first photoelectric transducing means passes through said insulation means and said second photoelectric transducing means, the light coming out of said second photoelectric transducing means is substantially uniform no matter through which part the light passes.

13. A unit according to claim 9, in which said first photoelectric transducing means includes first holding means for said first photosensitive elements while said second photoelectric transducing means includes second holding means for said second photosensitive elements, said holding means each having a surface opposing said insulating means, said first and said second photosensitive elements being respectively disposed on a surface opposed to said insulation means.

14. A unit according to claim 1, wherein said first and second photoelectric transducing means have non-linear electrical response characteristics with respect to the change in sharpness of an image to be formed thereon.

15. A unit according to claim 14, wherein said first and second photoelectric transducing means have mutually different electrical response characteristics with respect to the change in the sharpness of the image.

16. A unit according to claim 15, wherein said first photoelectric transducing means has a non-linear electrical response characteristic such that its output is increased with increase in the sharpness of the image and said second photoelectric transducing means has a non-linear electrical response characteristic such that its output is decreased with increase in the sharpness of the image.

17. A unit according to claim 14, wherein said first and second photoelectric transducing means have mutually different nonlinear resistance versus image sharpness response characteristics.

18. A unit according to claim 17, wherein said first photoelectric transducing means has a non-linear resistance characteristic such that the internal resistance value thereof decreases with increase in the sharpness of the image and said second photoelectric transducing means has a non-linear resistance value thereof increases with increase in the sharpness of the image.

19. An object image sharpness detecting system for detecting the sharpness of the image formed by the image forming optical system comprising;

I. a light-to-electrical signal converting unit disposed substantially at the image forming position of said optical system,

Ii. a detecting means for detecting the sharpness of the object image by detecting the variation of the electrical output of said light-to-electrical signal converting unit,

Iii. said converting unit including

Iii a. insulation means

Iii b. first and second photoelectric transducing means disposed on both sides of the insulation means and permitting the passage of a light beam,

Iv. said first photoelectric transducing means electrically connected to said detecting means comprising;

Iv a. a pair of belt-shaped electrode members having respective ends and disposed in such a manner that they do not cross each other and are wound in a bifilar winding which forms a center so that the one of the ends of each member is located near the center while the other end is located at the outside of the bifilar winding,

Iv b. a photoelectric semiconductor dispersed at least in the space of said bifilar winding formed by said both electrode pieces,

V. said second photoelectric transducing means electrically connected to said detecting means comprising;

V a. a belt-shaped photoconductive element folded back to form a middle located near the center and wound to form a bifilar winding, both of said ends being located external to the bifilar winding,

V b. a pair of the electrodes being connected respectively to said ends, whereby the sharpness of the object image is detected by detecting the output of the light-to-electrical signal converting unit.

20. A system according to claim 19, in which said photoconductive element of said second photoelectric transducing means overlaps said pair of the electrode pieces of said first photoelectric means but does not overlap said photoelectric semiconductor of said first photoelectric transducing means excepting at the center of the bifilar part formed by said pair of the electrode pieces of said first photoelectric transducing means.

21. A system according to claim 20, in which said first photoelectric transducing means includes first photoconductive element holding means while said second photoelectric transducing means includes second photoconductive element holding means, whereby said photoelectric semiconductors of said first and said second photoelectric transducing means are respectively disposed on the surfaces opposed to said insulation means of said photoconductive element holding means.

22. A system according to claim 20, in which said second photoconductive element holding means is formed so as to permit the passage of a light beam while said first photoelectric semiconductor holding means is formed so as to prevent said photoconductive element of said second photoelectric transducing means from being influence by the light beam from the surface opposite the surface facing to said insulation means.

23. A system according to claim 19, in which at least one of said photoconductive elements of said first and said second photoelectric transducing means is formed of CdS.

24. A system according to claim 19, in which said detecting means includes processing circuit means for comparing the output of said first photoelectric transducing means with that of said second photoelectric transducing means so as to produce as output an electrical signal corresponding to the comparison signal.

25. A system according to claim 24, in which said detecting means includes a compensating means for compensating the output of said processing circuit means in accordance with the light intensity of the object.

26. A system according to claim 25, wherein said compensating means includes operating circuit means coupled to said processing circuit means for detecting the light intensity on the basis of an output of said processing circuit means when said converting unit receives a diffused light beam.

27. A system according to claim 26, wherein said compensating means further comprises signal storing means coupled to said operating circuit means and said processing circuit means for storing an output signal of said operating circuit means and supplying said output signal to said processing circuit means.

28. A system according to claim 26, further comprises a light beam diffusion means selectively disposed between said image forming optical system and said light-to-electrical signal converting unit for diffusing the image passing through the image forming optical system over said unit, said operating circuit means detecting the light intensity on the basis of an output of said processing circuit means when said diffusion means is disposed between said optical system and said converting unit.

29. A system according to claim 26, further comprising a light diffusion means normally disposed between said image forming optical system and said light-to-electrical signal converting unit containing a liquid crystal layer, said light beam diffusion means selectively diffusing or retaining the image through said image forming optical system over the unit, said operating circuit means detecting the light intensity on the basis of an output of said processing circuit means said converting unit receives a light beam diffused by said liquid crystal layer.

30. A system according to claim 19, wherein at least a part of said image forming optical system is movable along an optical axis in order to change the image sharpness on said converting unit.

31. A system according to claim 30, further comprising indicating means electrically connected with said detecting means for indicating the degree of the image sharpness on the basis of an output of said detecting means.

32. A system according to claim 30, further comprising driving means electrically connected with said detecting means and operatively coupled with said movable part of said optical system for moving said movable part of said optical system along the axis on the basis of an output of said detecting means.

33. An image sharpness detecting system cooperating with an image forming optical system to detect an optimum degree of sharpness of an image projected thereby from an object comprising:

at least a pair of light-to-electrical signal converting units disposed before and behind the image forming position of said image forming optical system,

a detecting means for detecting the sharpness of the image of an object by detecting the variation of the electrical output of said pair of the light-to-electrical signal converting unit,

insulating means

first and the second photosensitive elements disposed on the insulating means opposed to each other;

said first photoelectric converting means electrically connected to said detecting means and comprising;

a pair of belt-shaped electrode members having short and long edges, the short edges being shorter than the longer edges, said members being disposed so that the electrode members do not contact each other and form an area having a center, the short edges being located near the center, the electrode members being wound bifilarly and the other shorter edges being located external to the area,

a photosensitive element disposed at least in the space of said bifilar part formed by said both electrode pieces,

said second photoelectric converting means electrically connected to said detecting means and comprising;

a belt-shaped photosensitive element having long and short sides and a middle, the short sides being shorter than the long sides, the photosensitive element being folded over a space having a center so that the middle of the long sides is located nearly at the center, said semiconductor being wound bifilarly similar to said first photoelectric transducing means and the both shorter sides being located external to the space,

a pair of the electrode pieces being connected to said both shorter bases,

said detecting means detecting the output of the light-to-electrical signal converting unit, said unit being disposed so that an element is also disposed near the center of said first and said second photoelectric converting means.

34. A system according to claim 33, in which light splitting means between said optical system and said pair of the light-to-electrical signal converting units split the optical axis of said optical system at least into the first and the second axis and said light-to-electrical signal converting units are separately disposed on said first and said second optical axis.

35. A system according to claim 34, in which said photosensitive element of said second photoelectric converting means overlaps said pair of the electrode pieces of said first photoelectric means but does not overlap said photosensitive element of said first photoelectric converting means except at the center of the bifilar part formed by said pair of the electrode pieces of said first photoelectric converting means.

36. A system according to claim 35, in which said first photoelectric transducing means includes first photosensitive element holding means while said second photoelectric converting means includes second photosensitive element holding means, whereby said photosensitive elements of said first and said second photoelectric converting means are respectively disposed on the surfaces facing said insulation means of said photosensitive element holding means.

37. A system according to claim 36, in which said second photosensitive element holding means permits passage of light while said first photosensitive element holding means is formed so as to prevent said semiconductive element of said second photoelectric converting means from being influenced by light from the surface opposing the surface facing said insulation means.

38. A system according to claim 33, in which at least one of said semiconductive elements of said first and said second photoelectric converting means is formed of CdS.

39. A system according to claim 33, in which said detecting means includes a differential amplifier means for comparing the output of said first photoelectric converting means with the output of said second photoelectric transducing means so as to produce as output an electrical signal in accordance with the comparison signal.

40. A system according to claim 39, in which said differential amplifier means contains a processing circuit.

41. A system according to claim 33, in which said pair of the light-to-electrical signal converting units are disposed on the optical axis of said optical system.

42. A system according to claim 41, in which the first light-to-electrical signal converting unit is disposed in such a manner that said photosensitive element of said second photoelectric converting means permits the passage of the light beam and overlaps only the photoelectric semiconductor of said first photoelectric transducing means and lies substantially wholly between said pair of the electrode pieces of said first photoelectric transducing means.

43. A system according to claim 42, in which said first light-to-electrical signal converting unit permits the passage of the light beam while when the light beam entering into said first photoelectric converting means passes through said insulation means and said second photoelectric converting means, the light beam coming out of said second photoelectric converting means is substantially uniform no matter through which part the light beam passes.

44. A system according to claim 43, in which the second light-to-electrical signal converting unit is disposed so that said photosensitive element of said second photoelectric converting means overlaps said pair of the electrode pieces of said first photoelectric converting means but does not overlap the photosensitive element of said first photoelectric converting means excepting at the center of the bifilar part formed by said pairs of the electrode pieces of said first photoelectric converting means.

45. A system according to claim 33, further comprising a beam splitting means arranged between said optical system and a plane substantially in the image plane in the optical path of said optical system to split an image-forming light beam entering said optical system into at least two portions, said converting units being arranged to receive respective ones of two beam portions split by said beam splitting means.

46. A system according to claim 33, wherein each of said first and second photoelectric transducing means of said converting units have non-linear electrical response characteristics with respect to the change in image sharpness.

47. A system according to claim 39, wherein said operational amplifier means comprises at least two operational amplifying circuits, and said converting units are each respectively connected with one of said amplifying circuits.

48. A system according to claim 42, wherein said detecting means further comprises differential amplifier means electrically connected with said operational amplifying circuits.

49. A system according to claim 48, wherein said detecting means further comprises compensating means for compensating the output of said differential amplifier means in accordance with the intensity of the light beam of image.

50. A system according to claim 49, wherein said compensating means comprises an operating circuit means coupled to said differential amplifier means for detecting the light intensity on the basis of an output of said differential amplifier means when said converting unit receives a diffused light beam.

51. A system according to claim 50, wherein said compensating means further comprises a signal storing means electrically coupled with both said operating circuit means and said operational amplifier means for storing an output signal of said operating circuit means and supplying said output signal to said operational amplifier means.

52. A system according to claim 51, further comprises a light beam diffusion means selectively disposed between said image forming optical system and said light-to-electrical signal converting unit so as to diffuse the image passing through said image forming optical system over said unit, said operating circuit means detecting the light intensity on the basis of an output of said differential amplifier means when said diffusion means is disposed between said optical system and said converting unit.

53. A system according to claim 51, further comprising light diffusion means normally disposed between said image forming optical system and said light-to-electrical signal converting unit and containing a liquid crystal layer, said light beam diffusion means selectively diffusing or passing the image coming through said image forming optical system over the unit, said operating circuit means detecting the light intensity on the basis of an output of said differential amplifier means when said converting unit receives the diffused light beam diffused by said liquid crystal layer.

54. A system according to claim 53, wherein each of said first and second photoelectrical transducing means of said converting units exhibit non-linear electrical response characteristics whose internal resistance values thereof reach a peak value when the sharpness of the image to be formed thereon reaches a maximum.

55. A light-to-electrical signal converting unit comprising;

I. first photoelectric transducing means having;

1a. a first photosensitive element forming a current path and having shorter and longer sides, the length of the shorter sides being substantially shorter than the length of the longer sides, and

1b. a first pair of electrodes each contacting a respective longer side of said first photosensitive element along the entire length thereof, and

Ii. second photoelectric transducing means having;

Iia. a transparent substrate,

Iib. a second photosensitive element formed on said substrate and having shorter and longer sides, the length of the shorter side being substantially shorter than the longer sides, and

Iic. a second pair of electrodes each contacting a respective shorter sides of said second photosensitive element,

Iii. said first and second photoelectric transducing means having mutually different non-linear electrical response characteristics with respect to change in sharpness of an image to be formed thereon,

Iv. said first pair of electrodes having a geometry substantially identical with that of the second photosensitive element, and

V. said first photoelectric transducing means overlying said second photoelectric transducing means so that said second photosensitive element is in registry with the first pair of electrodes.

56. A unit according to claim 55, wherein said electrical response characteristic of both of said first and second photoelectric transducing means has a peak value when the sharpness of the image to be formed thereon becomes maximum.

57. A unit according to claim 56, wherein said first photoelectric transducing means has a non-linear electrical response characteristic whose output increases with increasing sharpness of the image and said second photoelectric transducing means has a non-linear electrical response characteristic whose output decreases with increasing sharpness of the image.

58. A unit according to claim 55, wherein said first and second photosensitive elements are composed of photoconductive material.

59. A unit according to claim 58, wherein said first and second photoelectric transducing means have electrical response characteristics whose internal resistance values thereof reach a peak value when the sharpness of an image to be formed thereon becomes maximum.

60. A unit according to claim 59, wherein said first photoelectric transducing means has a non-linear resistance characteristic with an internal resistance value that decreases with increasing image sharpness, and said second photoelectric transducing means has a non-linear resistance characteristic with an internal resistance value that increases with increasing image sharpness.

61. A unit according to claim 55, wherein said second photosensitive element exhibits a bifilar-spiral form on said substrate with the center portion of the spiral coinciding substantially with the center portion of said substrate.

62. An image sharpness detecting system cooperating with an image-forming optical system to detect an optimum degree of sharpness of an image projected thereby from an object comprising;

a light-to-electrical signal converting unit positioned substantially at the focus of said optical system, and

detecting means coupled to said converting unit for detecting the optimum degree of said object image on the basis of electrical output of said converting unit,

said light-to-electrical signal converting unit including first photoelectric transducing means having a first non-linear electrical response characteristic, and having a first photosensitive element forming a current path, said element having shorter and longer sides, the length of the shorter sides being substantially shorter than the length of the longer sides, said first photoelectric transducing means having a first pair of electrodes each contacting a respective longer sides of said first photosensitive element along the entire length of the side,

said converting unit further including second photoelectric transducing means having a second non-linear electrical response characteristic different from said first non-linear electrical response characteristic and having a transparent substrate as well as a second photosensitive element formed thereon on the substrate, said second photosensitive element having shorter and longer sides, the length of the shorter side being substantially shorter than the longer sides, said second photoelectric transducing means having a second pair of electrodes contacting the respective shorter sides of said second photosensitive element along the entire length thereof,

said first pair of electrodes having a geometry substantially identical to that of the second photosensitive element, and

said first photoelectric transducing means being arranged adjacent said second photoelectric transducing means so that second photosensitive element is in alignment with the first pair of electrodes.

63. A system according to claim 62, wherein said second photosensitive element exhibits a bifilar-spiral form on said substrate with the center portion of the spiral coinciding substantially with the center portion of said substrate.

64. A system according to claim 63, wherein said first and second photosensitive elements are composed of photoconductive material.

65. A system according to claim 64, wherein said first photoelectric transducing means has an internal resistance value that decreases with increasing image sharpness, and said second photoelectric transducing means has an internal resistance value that increases with increasing image sharpness.

Other info:

Inventors: Schulz, Hansrichard

Application Number: 545473
Filing Date: 1975-01-30
Publication_date: 1977-04-19
Assignee:
Primary Class(es): 250/214.1 250/201.7, 257/E31.053, 396/111, 396/147
Other Classes:
US Patent Ref:

3830571	Aug, 1974	Imai et al.	250/201.
3838275	Sep, 1974	Stauffer	250/204.
3857031	Dec, 1974	Sinclair et al.	250/201.
3875401	Apr, 1975	Stauffer	354/195.

Other Refs:
Primary Examiner: Nelms, David C.
Assistant Examiner:
Attorney: