Electronic imaging apparatus with anti-dust function

• US 20040047625A1
• Filed: 05/15/2003
• Published: 03/11/2004
• Est. Priority Date: 05/17/2002
• Status: Active Grant

• Current Assignee: Olympus Corporation
• Original Assignee: Olympus Corporation
• Inventors: Ito, Junichi, Kawai, Sumio, Takizawa, Hiroyuki
• Granted Patent: US 7,492,408 B2
• Time in Patent Office: Days
• US Class Current: 396/429
• CPC Class Codes: G03B 17/48 adapted for combination with other photographic or optical apparatus
• CPC Class Codes: G03B 19/12 Reflex cameras with single objective and a movable reflector or a partly-transmitting mirror
• 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 23/60 Control of cameras or camera modules
• CPC Class Codes: H04N 23/81 for suppressing or minimising disturbance in the image signal generation

Abstract

An electronic imaging apparatus includes an imaging optical system which forms an optical image of an object. A photoelectric conversion element converts the optical image into an electric signal. The optical element is arranged between the imaging optical system and the photoelectric conversion element. An excitation unit vibrates the optical element at a set frequency, and vibrates the optical element at least in an imaging operation of the photoelectric conversion element.

Claims

1. An electronic imaging apparatus comprising:

an imaging optical system which forms an optical image of an object;

a photoelectric conversion element which converts the optical image into an electric signal;

an optical element arranged between the imaging optical system and the photoelectric conversion element; and

exciting means for vibrating the optical element at a set frequency,

wherein the exciting means vibrates the optical element at least in an imaging operation of the photoelectric conversion element.

2. An electronic imaging apparatus having imaging means for converting an optical image of an object into an electric signal, comprising:

an optical element arranged on a front surface of the imaging means;

exciting means for vibrating the optical element; and

controlling means for vibrating the optical element by controlling the exciting means in execution of an imaging operation by the imaging means.

3. The electronic imaging apparatus according to claim 2, wherein the controlling means controls so as to start supply of a drive control signal to the exciting means with a timing in advance of start of an imaging operation of the electronic imaging apparatus.

4. The electronic imaging apparatus according to claim 3, wherein the timing in advance of start of the imaging operation of the electronic imaging apparatus is a timing before start of an imaging preparation operation.

5. The electronic imaging apparatus according to claim 3, wherein the timing in advance of the imaging operation of the electronic imaging apparatus is a timing excluding a timing of a maximum power consumption in the imaging preparation operation by the electronic imaging apparatus.

6. An electronic imaging apparatus including imaging means for converting an optical image of an object into electric signal, comprising:

an imaging optical system which leads an object light flux onto a photoelectric conversion surface of the imaging means;

anti-dust filter means arranged in front of the photoelectric conversion surface of the imaging means;

exciting means for vibrating the anti-dust filter means; and

controlling means for controlling so as to remove dust which has adhered on the anti-dust filter by driving the exciting means at least in execution of an imaging operation by the imaging means.

7. The electronic imaging apparatus according to claim 6, wherein the electronic imaging apparatus includes preparing means for executing a preparation operation in advance of an imaging operation by the imaging means, and the controlling means starts the dust removing operation in advance of start of the preparation operation.

8. The electronic imaging apparatus according to claim 7, wherein the preparation operation is a retiring operation of a movable mirror provided in an imaging light path.

9. The electronic imaging apparatus according to claim 7, wherein the preparation operation is a closing operation of a diaphragm mechanism to a set position, provided in the imaging optical system.

10. The electronic imaging apparatus according to claim 6, wherein the electronic imaging apparatus comprises shutter means for adjusting an irradiation time of the object light flux onto the photoelectric conversion surface, and the controlling means is set so as to start the dust removing operation before an opening operation of the shutter means.

11. The electronic imaging apparatus according to claim 10, wherein, when a shutter second time of the shutter means is longer than a predetermined time, the controlling means terminates the dust removing operation before a closing operation of the shutter means is executed.

12. The electronic imaging apparatus according to claim 10, wherein, when the dust removing operation is continuously performed for a predetermined time before the closing operation of the shutter means is executed, the controlling means stops the dust removing operation.

13. An electronic imaging apparatus comprising:

an imaging optical system which forms an optical image of an object;

a photoelectric conversion element which converts the optical image into an electric signal;

an optical element arranged between the imaging optical system and the photoelectric conversion element;

a piezoelectric element fixed to the optical element;

a control circuit which outputs a frequency signal at least in an imaging operation of the photoelectric conversion element; and

a drive circuit which supplies a cyclic voltage signal to the piezoelectric element in accordance with the frequency signal.

14. An electronic imaging apparatus which can attach/detach an accessory device, comprising:

imaging means for converting an optical image of an object into an electric signal;

an optical element arranged on a front surface of the imaging means; and

dust removing means for removing dust which has adhered to a surface of the optical element by vibrating the optical element,

wherein the electronic imaging apparatus is controlled so as to perform a dust removing operation by the dust removing means in accordance with attachment of the accessory device.

15. The electronic imaging apparatus according to claim 14, wherein the accessory device is at least one of a replaceable imaging lens, an image storage medium which records an electronic image picked up by the imaging means, a strobe device and an external power supply.

16. An electronic imaging apparatus having imaging means for converting an optical image of an object into an electric signal, comprising:

an accessory device which can be attached/detached to the electronic imaging apparatus;

an optical element arranged on a front surface of the imaging means;

exciting means for vibrating the optical element; and

drive controlling means for driving the exciting means by supplying a frequency signal to the exciting means,

wherein the drive controlling means has a resonance frequency detecting mode to drive the exciting means in order to detect a resonance frequency of the optical element and a dust removing mode to drive the exciting means in order to remove dust which has adhere to the optical element, and

the electronic imaging apparatus controls so as to continuously execute the resonance frequency detecting mode and the dust removing mode at a timing that the accessory device is attached.

17. An electronic imaging apparatus having imaging means for converting an optical image of an object into an electric signal, comprising:

an imaging optical system which can be attached/detached to the electronic imaging apparatus and forms the optical image on the imaging means;

an optical element arranged between the imaging optical system and the imaging means;

exciting means for vibrating the optical element; and

driving means for driving the exciting means by supplying a frequency signal to the exciting means,

wherein the drive controlling means controls so as to vibrate the optical element by driving the exciting means when the imaging optical system is attached to the electronic imaging apparatus.

18. The electronic imaging apparatus according to claim 17, wherein the drive controlling means executes a resonance point detecting operation to detect a resonance frequency of the optical element and thereafter drives the exciting means at a resonance frequency detected by the resonance point detecting operation.

19. The electronic imaging apparatus according to claim 17, wherein the drive controlling means has a resonance frequency detecting mode to drive the exciting means in order to detect a resonance frequency of the optical element and a dust removing mode to drive the exciting means in order to remove dust which has adhered to the optical element,

continuously executes the resonance frequency detecting mode and the dust removing mode at a timing that the imaging optical system is attached, and

controls so as to execute only the dust removing mode at a predetermined timing in advance of the imaging operation.

20. An electronic imaging apparatus comprising:

an attachable/detachable imaging optical system;

a photoelectric conversion element which converts an optical image of an object led by the imaging optical system into an electric signal;

an optical element arranged between the imaging optical system and the photoelectric conversion element;

a piezoelectric element fixed to the optical element;

a control circuit which outputs a frequency signal in response to attachment of the imaging optical system; and

a drive circuit which supplies a cyclic voltage signal to the piezoelectric element in accordance with the frequency signal.

21. An electronic imaging apparatus comprising:

an optical system which forms an object image;

an imaging element which converts the object image formed by the optical system into an electric signal;

an anti-dust optical member arranged between the optical system an the imaging element; and

exciting means for generating a flexural progressive wave to the anti-dust optical member by vibrating the anti-dust optical member.

22. The electronic imaging apparatus according to claim 21, wherein the flexural progressive wave generated by the exciting means has a substantially symmetrical shape when seen from an optical axis of the optical system at an arbitrary time.

23. The electronic imaging apparatus according to claim 21, wherein the exciting means comprises:

a first excitation member arranged at a peripheral portion of an effective image area through which the object light flux of the anti-dust optical member passes;

a second exciting member arranged at a position shifted from the first excitation member by a distance of substantially ¼

of a wavelength of the flexural progressive wave in a traveling direction of the flexural progressive wave; and

driving means for applying a first cyclic voltage signal to the first excitation member and applying a second cyclic voltage signal whose phase is shifted from the first cyclic voltage signal by approximately 90 degrees to the second excitation member.

24. The electronic imaging apparatus according to claim 23, wherein the first excitation member is arranged on one surface of the anti-dust optical member and the second excitation member is arranged on the other surface of the anti-dust optical member.

25. The electronic imaging apparatus according to claim 23, wherein the first excitation member and the second excitation member are arranged on one surface side of the anti-dust optical member, and the second excitation member is arranged so as to be superimposed on the first excitation member.

26. The electronic imaging apparatus according to claim 23, wherein the first excitation member is arranged at an outer peripheral portion on one surface of the anti-dust optical member, and the second excitation member is arranged on the same surface as an arrangement surface of the first excitation member and on the inner side away from the first excitation member.

27. The electronic imaging apparatus according to claim 23, wherein the first excitation member and the second excitation member are arranged on one surface of the anti-dust optical member, and generate a concentric bending vibration to the anti-dust optical member.

28. An electronic imaging apparatus comprising:

an optical system which forms an image of an object;

an imaging element which converts the object image into an electric signal;

an anti-dust optical member arranged between the optical system and the imaging element;

a first excitation member and a second excitation member arranged at a peripheral edge portion of the anti-dust optical member; and

driving means for applying cyclic voltage signals having different phases to the first excitation member and the second excitation member so as to generate a flexural progressive wave to the anti-dust optical member.

29. The electronic imaging apparatus according to claim 28, wherein the driving means generates a standing wave to the anti-dust optical member by applying a cyclic voltage signal to either the first excitation member or the second excitation member or applying cyclic voltage signals having the same phase to both of the first excitation member and the second excitation member.

30. The electronic imaging apparatus according to claim 29, wherein the driving means sequentially generate the flexural progressive wave and the standing wave to the anti-dust optical member.

31. An electronic imaging apparatus comprising:

imaging means for converting an optical image of an object into an electric signal;

an anti-dust filter arranged on a front surface of the imaging means;

exciting means for vibrating the anti-dust filter; and

measuring means for measuring a power supply voltage,

wherein the exciting means changes a vibration frequency of the anti-dust filter in accordance with the power supply voltage measured by the measuring means.

32. The electronic imaging apparatus according to claim 31, wherein the exciting means vibrates the anti-dust filter at a first frequency close to a resonance frequency of the anti-dust filter when the power supply voltage is not more than a predetermined voltage, and vibrates it at a second frequency deviating from the resonance frequency when the power supply voltage is higher than the predetermined voltage.

33. The electronic imaging apparatus according to claim 32, wherein the second frequency is a frequency with which the anti-dust filter cannot be destroyed even if the power supply voltage is higher than the predetermined voltage.

34. The electronic imaging apparatus according to claim 32, wherein the first and second frequencies are values inherent to the anti-dust filter and they are set on an assembling stage of the electronic imaging apparatus.

35. The electronic imaging apparatus according to claim 32, wherein the predetermined voltage is a voltage with which the anti-dust filter may be possibly destroyed when the anti-dust filter is vibrated in the vicinity of the resonance frequency of the anti-dust filter.

36. An electronic imaging apparatus comprising:

imaging means for converting an optical image of an object into an electric signal;

an anti-dust filter arranged on a front surface of the imaging means;

exciting means for vibrating the anti-dust filter; and

measuring means for measuring a power supply voltage,

wherein the exciting means changes a time in which the anti-dust filter is vibrated in accordance with the power supply voltage measured by the measuring means.

37. The electronic imaging apparatus according to claim 36, wherein the exciting means vibrates the anti-dust filter for a first predetermined time when the power supply voltage is higher than a predetermined voltage, and vibrates the anti-dust filter for a second predetermined time longer than the first predetermined time when the power supply voltage is not more than the predetermined voltage.

38. The electronic imaging apparatus according to claim 37, wherein the first and second predetermined times have values determined by a characteristic of the anti-dust filter.

39. An electronic imaging apparatus comprising:

an imaging element;

an anti-dust filter arranged on a front surface of the imaging element;

a piezoelectric element arranged at a peripheral edge portion of the anti-dust filter;

a drive circuit which vibrates the piezoelectric element;

a measurement circuit which outputs digital data by measuring a power supply voltage; and

a control circuit which adjusts a frequency signal used to vibrates the piezoelectric element and supplies it to the drive circuit in accordance with a measurement result of the measurement circuit,

wherein the electronic imaging apparatus further comprises a dust removing mechanism which vibrates the anti-dust filter by vibration of the piezoelectric element and thereby removes dust which has adhered to a surface of the anti-dust filter.

40. The electronic imaging apparatus according to claim 39, wherein the control circuit adjusts a frequency of the frequency signal or a time in which the frequency signal is supplied to the drive circuit in accordance with a power supply voltage measured by the measurement circuit.

41. The electronic imaging apparatus according to claim 40, wherein the control circuit compares a power supply voltage measured by the measurement circuit with a predetermined value, supplies a signal having a frequency close to a resonance frequency of the anti-dust filter when the power supply voltage is not more than the predetermined voltage, and supplies a signal having a frequency deviating from the resonance frequency to the drive circuit when the power supply voltage is higher than the predetermined value.

42. The electronic imaging apparatus according to claim 39, wherein the control circuit compares a power supply voltage measured by the measurement circuit with a predetermined value, supplies the frequency signal to the drive circuit for a first predetermined time when the power supply voltage is higher than a predetermined value, and supplies the frequency signal to the drive circuit for a second predetermined time longer than the first predetermined time when the power supply voltage is not more than the predetermined value.

43. An electronic imaging apparatus having imaging means for photo-electrically converting an object image and having a function capable of selectively producing a sound in and out of an audible range, comprising:

a member which is arranged on a front surface of the imaging means and has the transmittance capable of vibrating;

exciting means for vibrating the member; and

controlling means for generating at least vibration and generating a sound used to notify a state by selectively changing a vibration conformation by the exciting means and giving driving.

44. The electronic imaging apparatus according to claim 43, wherein the vibration conformation adjusts and controls an ON/OFF timing of a signal power to be supplied to the exciting means, or adjusts and controls a resonance frequency to be supplied to the exciting means.

45. An electronic imaging apparatus having imaging means for converting an optical image of an object into an electric signal, comprising:

an optical element arranged on a front surface of the imaging means;

exciting means for vibrating the optical element; and

controlling means for supplying a frequency signal used to vibrate the optical element to the exciting means,

wherein the controlling means can vibrates with a sound the optical element by adjusting the frequency.

46. The electronic imaging apparatus according to claim 45, wherein the sound vibration is used to notify a state of the electronic imaging apparatus.

47. The electronic imaging apparatus according to claim 46, wherein the sound vibration has a second sound vibration state which performs both an operation to remove dust which has adhered to the optical element and a notification operation.

48. The electronic imaging apparatus according to claim 47, wherein the sound vibration is executed in advance of the imaging operation of the imaging means.

49. An electronic imaging apparatus comprising imaging means for converting an optical image of an object into an electric signal, comprising:

an imaging optical system which leads an object light flux onto a photoelectric conversion surface of the imaging means;

anti-dust filter means arranged in front of the photoelectric conversion surface of the imaging means;

exciting means for vibrating the anti-dust filter means; and

controlling means for supplying a frequency signal used to vibrate the anti-dust filter with respect to the exciting means,

wherein the controlling means has a first vibration mode to vibrate the anti-dust filter soundlessly and a second vibration mode to vibrate the anti-dust filter with a sound, and the second vibration mode is executed when displaying a state of the electronic imaging apparatus with a sound.

50. The electronic imaging apparatus according to claim 49, wherein the electronic imaging apparatus includes means for detecting a focusing state of the imaging optical system and adjusting the focusing state of the imaging optical system in accordance with a result.

51. The electronic imaging apparatus according to claim 49, wherein the second vibration mode is used for focus display of the imaging optical system.

52. The electronic imaging apparatus according to claim 49, wherein the electronic imaging apparatus can attach thereto recording means used to record an output from the imaging means, and

the controlling means executes the second vibration mode when the recording means is not attached.

53. An electronic imaging apparatus including an anti-dust mechanism, comprising:

a photoelectric conversion element which converts an optical image of an object into an electric signal;

an anti-dust member arranged on a front surface of the photoelectric conversion element;

exciting means for vibrating the anti-dust member and causing it to perform a dust removing operation;

frequency varying means for sequentially changing a vibration frequency of the anti-dust member vibrated by this exciting means; and

monitor means for monitoring an amplitude value when the anti-dust member is vibrating, and controlling the dust removing operation in accordance with the monitored amplitude value.

54. The electronic imaging apparatus according to claim 53, wherein the exciting means vibrates the anti-dust member in accordance with a frequency signal supplied from the frequency varying means.

55. The electronic imaging apparatus according to claim 54, wherein the exciting means vibrates the anti-dust member in accordance with a plurality of frequency signals in a predetermined range sequentially supplied from the frequency varying means.

56. The electronic imaging apparatus according to claim 55, wherein the predetermined frequency range is a range including a resonance frequency of the anti-dust member.

57. The electronic imaging apparatus according to claim 53, wherein the monitor means monitors an amplitude value with which the anti-dust member may be destroyed, and stops the dust removing operation when this amplitude value is exceeded.

58. An electronic imaging apparatus comprising:

an imaging optical system which forms an optical image of an object;

a photoelectric conversion element which converts the optical image into an electric signal;

an anti-dust filter arranged between the imaging optical system and the photoelectric conversion element;

a piezoelectric element which is integrally arranged at a part of the anti-dust filter;

a drive circuit which applies a voltage signal to the piezoelectric element and drives the piezoelectric element;

a control circuit which supplies a drive signal to the drive circuit so as to vibrate the anti-dust filter by vibrating the piezoelectric element;

a monitor circuit which monitors a vibration state of the piezoelectric element and outputs a monitor signal to the control circuit,

wherein the control circuit sequentially changes a drive signal to be supplied to the drive circuit in such a manner a vibration frequency of the anti-dust filter sequentially varies, and stops supply of the drive signal when a level of the monitor signal supplied from the monitor circuit exceeds a predetermined value while this change.

59. The electronic imaging apparatus according to claim 58, wherein, after the level of the monitor signal from the monitor circuit exceeds a predetermined value, the control circuit stops supply of the drive signal after a predetermined time.

60. The electronic imaging apparatus according to claim 58, wherein the drive circuit changes a frequency of a voltage signal to be applied to the piezoelectric element in accordance with a drive signal from the control circuit.

61. An electronic imaging apparatus having an anti-dust mechanism which removes dust which has adhered on a surface of an anti-dust filter arranged on a front surface of a photoelectric conversion element which converts an optical image of an object into an electric signal by vibrating the anti-dust filter, comprising:

monitor means for detecting an amplitude value of the anti-dust filter;

storing means for previously storing an output value of the monitor means when the anti-dust filter is vibrated in the vicinity of a resonance frequency of the anti-dust filter; and

judging means which compares the output value of the monitor means with a stored value in the storing means in execution of an dust removing operation by the anti-dust filter, and judges whether a foreign particle exists on the anti-dust filter.

62. The electronic imaging apparatus according to claim 61, wherein the judging means determines that a foreign particle exists on the anti-dust filter when an output value of the monitor means is extremely small with respect to the stored value.

63. The electronic imaging apparatus according to claim 61, wherein, when the output value of the monitor means is less than a predetermined ratio with respect to the stored value, the judging means determines that a foreign particle exists on the anti-dust filter.

64. The electronic imaging apparatus according to claim 61, further comprising warning means for performing warning display when the judging means determines that a foreign particle exists on the anti-dust filter.

65. The electronic imaging apparatus according to claim 61, wherein, when the judging means determines that a foreign particle exists on the anti-dust filter, a subsequent imaging operation is stopped.

66. An electronic imaging apparatus comprising:

an imaging optical system which forms an optical image of an object;

a photoelectric conversion element which converts the optical image of the object formed by the imaging optical system into an electric signal;

an anti-dust filter arranged between the imaging optical system and the photoelectric conversion element;

a piezoelectric element which is integrally arranged at a part of the anti-dust filter;

a drive circuit which vibrates the piezoelectric element;

a control circuit which supplies drive control data to the drive circuit so as to vibrates the anti-dust filter by vibrating the piezoelectric element;

a monitor circuit which monitors a vibration state of the piezoelectric element and supplies its monitor output to the control circuit;

resonance frequency detecting means for detecting a resonance frequency of an anti-dust mechanism including the anti-dust filter from a change in level of the monitor output from the monitor circuit while the control circuit sequentially changes the drive control data to be supplied to the drive circuit in such a manner that a vibration frequency of the anti-dust filter sequentially varies;

storing means for storing the resonance frequency and a monitor output value of the monitor circuit at the resonance frequency;

dust removing means for vibrating the anti-dust filter based on the resonance frequency information in connection with an imaging operation;

judging means for comparing the monitor output value of the monitor circuit with a stored value in the storing means and judges whether the both values have a predetermined relationship in a dust removing operation by the dust removing means; and

determining means for determining whether the imaging operation is to be continued in accordance with a judgment result of the judging means.

67. The electronic imaging apparatus according to claim 66, wherein the judging means judges that a foreign particle exists on the anti-dust filter when the monitor output value of the monitor circuit is smaller than a stored value in the storing means.

68. The electronic imaging apparatus according to claim 66, wherein the judging means judges that a foreign particle exists on the anti-dust filter when the monitor output value of the monitor circuit is less than a predetermined ratio with respect to the stored value in the storing means.

69. The electronic imaging apparatus according to claim 66, further comprising a display circuit which performs warning display when the judging means judges that a foreign particle exists on the anti-dust filter.

70. The electronic imaging apparatus according to claim 66, wherein the imaging operation is stopped when the judging means judges that a foreign particle exists on the anti-dust filter.