Camera and image pickup device unit which reduce influence of dust image quality

• US 7,339,623 B2
• Filed: 11/20/2002
• Issued: 03/04/2008
• Est. Priority Date: 05/27/2002
• Status: Active Grant

• Current Assignee: OM Digital Solutions Corporation
• Original Assignee: Olympus Optical Company Ltd. (Olympus Corporation)
• Inventors: Kawai, Sumio
• Primary Examiner(s): Ho; Tuan
• Assistant Examiner(s): Bemben; Richard M.
• Application Number:
  US10/300,728
• Publication Number:
  US 20030218685A1
• Time in Patent Office: 1,931 Days
• Field of Search: 348/335, 348/340, 348/357, 348/374
• US Class Current: 348/340
• CPC Class Codes: H04N 23/52 Elements optimising image sensor operation, e.g. for electromagnetic interference [EMI] protection or temperature control by heat transfer or cooling elements
• CPC Class Codes: H04N 23/55 Optical parts specially adapted for electronic image sensors; Mounting thereof
• CPC Class Codes: H04N 23/811 by dust removal, e.g. from surfaces of the image sensor or processing of the image signal output by the electronic image sensor

Abstract

A camera is provided which includes a dust-proofing member having a substantially circular or polygonal plate-shape and a transparent portion at an area having at least a predetermined length in a radial direction from a center of the dust-proofing member. The transparent portion is opposed to a front of an optical device at a predetermined interval, and an interval of an equivalent optical path length of at least 5 mm is provided between a surface of the dust-proofing member and the photoelectrically converting surface of the image pick-up device. And a sealing structure portion is arranged at a portion formed by opposing the image pick-up device and the dust-proofing member. The sealing structure seals a space portion that is substantially sealed at peripheral portions of the image pick-up device and the dust-proofing member.

Claims

1. A camera comprising:

an image pick-up device which obtains an image signal corresponding to beams irradiated onto a photoelectrically converting surface thereof;

an exchangeable photographing lens which inputs a subject image onto the photoelectrically converting surface of the image pick-up device;

an image signal processing circuit which converts an image signal obtained from the image pick-up device, corresponding to an image formed onto the photoelectrically converting surface of the image pick-up device, into a signal suitable to recording;

a dust-proofing member having a substantially circular or polygonal plate-shape and comprising a transparent portion at an area having at least a predetermined length in a radial direction from a center of the dust-proofing member, wherein the transparent portion is opposed to a front of the photographing lens at a predetermined interval, and wherein an interval of an equivalent optical path length of at least 5 mm is provided between a surface of the dust-proofing member and the photoelectrically converting surface of the image pick-up device;

a vibration generating member, for vibrating the dust-proofing member, arranged outside an area through which the beams pass through the dust-proofing member, wherein the vibration generating member includes a piezoelectric element made of piezoelectric ceramics; and

a sealing structure portion arranged at a portion formed by opposing the image pick-up device and the dust-proofing member, the sealing structure portion sealing a space portion that is substantially sealed at peripheral portions of the image pick-up device and the dust-proofing member.

2. The camera according to claim 1, wherein the vibration generating member causes the dust-proofing member to vibrate in a standing wave.

3. The camera according to claim 1, wherein the dust-proofing member comprises an optical low-pass filter.

4. The camera according to claim 1, wherein the dust-proofing member comprises an infrared cut-off filter.

5. The camera according to claim 1, wherein the dust-proofing member comprises a protecting glass of the image pick-up device.

6. The camera according to claim 1, wherein an optical low-pass filter is arranged between the image pick-up device and the dust-proofing member.

7. The camera according to claim 1, wherein an infrared-cut-off filter is arranged between the image pick-up device and the dust-proofing member.

8. A camera comprising:

an image pick-up device which obtains an image signal corresponding to beams irradiated onto a photoelectrically converting surface thereof;

an optical member having a first surface opposed to a front of the image pick-up device at a predetermined interval; and

a sealing structure portion arranged at a portion formed by opposing the image pick-up device and the optical member, the sealing structure portion sealing a space portion that is substantially sealed at peripheral portions of the image pick-up device and the optical member,

wherein a dimension of an interval between the photoelectrically converting surface of the image pick-up device and a second surface of the optical member is set such that when positioning an object having a diameter of 1/10 or less of an exit pupil of a photographing lens on the second surface of the optical member, a density of a shade formed onto the photoelectrically converting surface is approximately 5% or less of a density of a shade formed by the object when placing the second surface of the optical member at a position of an equivalent optical path length of 1 mm in air from the photoelectrically converting surface.

9. The camera according to claim 8, wherein a dimension of the interval has an equivalent optical path length of 5 mm or more in air.

10. The camera according to claim 8, further comprising:

a vibration generating member arranged at the peripheral portion of the optical member for vibrating the optical member.

11. An image pick-up device unit comprising:

an image pick-up device which obtains an image signal corresponding to beams irradiated onto a photoelectrically converting surface thereof;

an optical member having a first surface opposed to a front of the image pick-up device at a predetermined interval; and

a sealing structure portion arranged at a portion formed by opposing the image pick-up device and the optical member, and the sealing structure portion sealing a space portion that is substantially sealed at peripheral portions of the image pick-up device and the optical member,

wherein a condition for preventing formation of an original shade of an object onto a second surface of the optical member is set to establish a relationship of an equivalent optical path length L in air between the object and the photoelectrically converting surface of the image pick-up device, such that;

L>

A×

d/D

where a diameter of an exit pupil of a photographing lens is designated by D, a diameter of the object is d, and an equivalent optical path length in air from a position of the exit pupil to the photoelectrically converting surface of the image pick-up device is designated by A.

12. The image pick-up device unit according to claim 11, further comprising:

a vibration generating member arranged at the peripheral portion of the optical member for vibrating the optical member.

13. An image pick-up device unit applicable to a camera to which a photographing lens is exchangeably attached, said image pick-up unit comprising:

an image pick-up device which obtains an image signal corresponding to beams irradiated onto a photoelectrically converting surface thereof;

a plate-shaped optical member having a first surface opposed to a front of the image pick-up device at a predetermined interval;

a vibration generating member, for vibrating the optical member, arranged outside an area through which the beams pass to be irradiated onto the photoelectrically converting surface of the image pick-up device, wherein the vibration generating member includes a piezoelectric element made of piezoelectric ceramics; and

a sealing structure portion arranged at a portion formed by opposing the image pick-up device and the optical member, the sealing structure portion sealing a space portion that is substantially sealed at peripheral portions of the image pick-up device and the optical member,

wherein an interval between the photoelectrically converting surface of the image pick-up device and a second surface of the optical member is set such that when a non-transparent object having a diameter of not more than 50 μ

m is positioned on the second surface of the optical member, a shade density of a shade of the object on the photoelectrically converting surface of the image pick-up device is not more than 5%.

14. A camera comprising:

an exchangeable photographing lens;

an image pick-up device which obtains an image signal corresponding to beams irradiated onto a photoelectrically converting surface thereof;

a plate-shaped optical member having a first surface opposed to a front of the image pick-up device at a predetermined interval;

a vibration generating member, for vibrating the optical member, arranged outside an area through which the beams pass to be irradiated onto the photoelectrically converting surface of the image pick-up device, wherein the vibration generating member includes a piezoelectric element made of piezoelectric ceramics; and

a sealing structure portion arranged at a portion formed by opposing the image pick-up device and the optical member, the sealing structure portion sealing a space portion that is substantially sealed at peripheral portions of the image pick-up device and the optical member,

wherein an interval between the photoelectrically converting surface of the image pick-up device and a second surface of the optical member is set to have a dimension such that when a non-transparent object having a diameter of not more than 50 μ

m is positioned on the second surface of the optical member, a shade density of a shade of the object on the photoelectrically converting surface of the image pick-up device is not more than 5%.

15. The camera according to claim 14, wherein the dimension of the interval is determined based on a size of an exit pupil of the photographing lens.

16. The camera according to claim 14, wherein the dimension of the interval is determined based on a focusing distance of the photographing lens.

17. The camera according to claim 14, wherein the dimension of the interval is determined based on a distance from a position of the exit pupil of the photographing lens to the photoelectrically converting surface of the image pick-up device.

18. The camera according to claim 14, wherein the dimension of the interval is determined based on a size of an exit pupil of the photographing lens, a focusing distance of the photographing lens, and a distance from a position of an exit pupil of the photographing lens to the photoelectrically converting surface of the image pick-up device.

19. The camera according to claim 14, wherein the dimension of the interval is determined based on a pixel interval of the image pick-up device.

20. An image pick-up device unit applicable to a camera to which a photographing lens is exchangeably attached, said image pick-up unit comprising:

an image pick-up device which obtains an image signal corresponding to beams irradiated onto a photoelectrically converting surface thereof;

a dust-proofing member having a substantially circular or polygonal plate-shape and comprising a transparent portion at an area having at least a predetermined length in a radial direction from a center of the dust-proofing member, wherein an interval of an equivalent optical path length of at least 5 mm is provided between a surface of the dust-proofing member and the photoelectrically converting surface of the image pick-up device;

a vibration generating member, for vibrating the dust-proofing member, arranged outside an area through which the beams pass through the dust-proofing member, wherein the vibration generating member includes a piezoelectric element made of piezoelectric ceramics; and

a sealing structure portion arranged at a portion formed by opposing the image pick-up device and the dust-proofing member, the sealing structure portion sealing a space portion that is substantially sealed at peripheral portions of the image pick-up device and the dust-proofing member.

21. The image pick-up device unit according to claim 20, wherein the vibration generating member causes the dust-proofing member to vibrate in a standing wave.

22. The image pick-up device unit according to claim 20, wherein the dust-proofing member comprises an optical low-pass filter.

23. The image pick-up device unit according to claim 20, wherein the dust-proofing member comprises an infrared cut-off filter.

24. The image pick-up device unit according to claim 20, wherein the dust-proofing member comprises a protecting glass of the image pick-up device.

25. The image pick-up device unit according to claim 20, wherein an optical low-pass filter is arranged between the image pick-up device and the dust-proofing member.

26. The image pick-up device unit according to claim 20, wherein an infrared cut-off filter is arranged between the image pick-up device and the dust-proofing member.