Camera apparatus

• US 5,387,960 A
• Filed: 11/09/1993
• Issued: 02/07/1995
• Est. Priority Date: 02/09/1989
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Iijima, Ryunosuke, Hirasawa, Masahide, Toyama, Masamichi
• Primary Examiner(s): Gray, David M.
• Application Number:
  US08/150,533
• Time in Patent Office: 455 Days
• Field of Search: 354/400-409, 354/412, 354/286, 358/227, 358/228, 358/909
• US Class Current: 396/135
• CPC Class Codes: G02B 7/102 controlled by a microcomputer cameras with interchangeable lenses G03B17/14
• CPC Class Codes: H04N 23/663 for controlling interchangeable camera parts based on electronic image sensor signals
• CPC Class Codes: H04N 23/673 based on contrast or high frequency components of image signals, e.g. hill climbing method

Abstract

A camera system having a lens unit provided with an actuator for changing the state of an optical system by driving a driving part and a driving circuit which drives the actuator on the basis of a driving control instruction signal supplied in a given periodicity from a control circuit disposed on the side of a camera body. The lens unit is characterized in that the actuator driving timing of the driving circuit is arranged to differ from the timing at which the driving control instruction signal is supplied from the control circuit to the driving circuit.

Claims

1. A lens unit for use with a camera which provides a driving control signal having a predetermined periodicity, said lens unit comprising:

a) a driving part which varies a condition of an optical system of said lens unit;

b) an actuator for driving said driving part; and

c) driving control means for driving said actuator on the basis of receiving said driving control signal, said driving control means supplying a driving signal to said actuator in a periodicity different from said predetermined periodicity, the driving control signal coming from said camera side being asynchronous with said driving signal.

2. A lens unit according to claim 1, wherein said condition is a focal condition and wherein said driving part varies an image forming position of said optical system by driving a focusing lens to adjust focus of said optical system.

3. A lens unit according to claim 1 or 2 wherein said driving control means receives said drive control signal in a periodicity of a vertical synchronizing signal of a TV signal processed in said camera.

4. A lens unit according to claim 3, wherein said driving control signal indicates information on a driving speed and a driving direction of said actuator, wherein said driving control means is arranged to supply said driving signal in accordance with said information.

5. A lens unit according to claim 4, wherein said driving control means includes a microcomputer receiving said driving control signal and providing said driving signal to said actuator.

6. A lens unit according to claim 5, wherein said microcomputer sets a program providing an execution repeating cycle for generating said actuator driving signal at a periodicity which differs from the periodicity of said vertical synchronizing signal of said TV signal being processed in said camera.

7. A lens unit according to claim 1 or 2, wherein said actuator is a stepper motor.

8. A lens unit according to claim 1, wherein said lens unit is detachably mountable on a camera, and wherein said driving control means is provided with communication means for communication of information with said camera in a periodicity which is synchronized with the periodicity of a vertical synchronizing signal of a TV signal processed in said camera.

9. A lens unit which is detachably mountable on a camera which provides a driving control signal having a predetermined periodicity, said lens unit comprising:

a) a driving part which varies a condition of an optical system of said lens unit;

b) an actuator for driving said driving part; and

c) driving control means for supplying a driving signal to said actuator in a further periodicity on the basis of receiving said driving control signal from said camera, said driving control means being operative to change a driving state of said actuator at an end of one cycle of said driving control signal.

10. A lens unit according to claim 9, wherein said driving part is operative to change an image forming position of said optical system to adjust focus of said optical system, and wherein said actuator is a stepper motor which drives a focusing lens included in said optical system.

11. A lens unit according to claim 9 or 10, wherein said driving control means receives said drive control signal in a periodicity of a vertical synchronizing signal of a TV signal processed in said camera.

12. A lens unit according to claim 11, wherein said driving control signal indicates information on a driving speed and a driving direction of said actuator, and wherein said driving control means supplies said driving signal to said actuator in accordance with said information.

13. A lens unit according to claim 12, wherein said driving control means includes a microcomputer receiving said driving control signal and providing said driving signal to said actuator.

14. A lens unit according to claim 13, wherein said microcomputer sets a program providing an execution repeating cycle for generating said actuator driving signal at a periodicity which differs from the periodicity of said vertical synchronizing signal of said TV signal being processed in said camera.

15. A lens unit according to claim 9, wherein said driving control means changes a driving state of said actuator even before the end of a driving cycle of said actuator if the content of said driving control signal currently received from said camera differs from that of the driving control signal previously received.

16. A lens unit according to claim 15, wherein said driving control means is arranged to reverse the driving direction of said actuator even before the end of a driving cycle of said actuator when a signal indicating a change in the driving direction of said actuator is received from said camera.

17. A lens unit according to claim 16, wherein the driving periodicity of said actuator is set by a timer.

18. A lens unit detachably mountable on a body of a camera which provides a control information signal, said lens unit comprising:

a) driving means for varying an optical characteristic of said lens unit;

b) control means for receiving said control information signal and discriminating a characteristic of said camera according to said control information signal and for changing a driving characteristic of said driving means according to the result of the discrimination.

19. A lens unit according to claim 18, wherein said control means has a memory for storing driving information for said driving means and controls said driving means by selecting driving information from the contents of said memory in accordance with said control information signal.

20. A lens unit according to claim 19, wherein said driving information relates to a driving speed to be employed by said driving means.

21. A lens unit according to claim 19 or 20, wherein said driving means includes a motor which is arranged to vary said optical characteristic, and wherein said motor is controlled by a pulse width modulation (PWM) signal on the basis of said control information signal and in synchronism with the periodicity of said control information signal.

22. A lens unit according to claim 21, wherein said control means is arranged to control an on-period of said PWM signal in accordance with a characteristic of said control information signal.

23. A lens unit according to claim 22, wherein the characteristic of said control information signal is a vertical synchronizing signal frequency conforming to a TV signal system employed by said camera body, and wherein said control means is operative to discriminate the periodicity of said control information signal transmitted from said camera body.

24. A lens unit according to claim 23, wherein said driving means adjusts focus of said optical system.

25. A lens unit according to claim 22, wherein the characteristic of said control information signal is a vertical synchronizing signal frequency conforming to a TV signal system employed by said camera body.

26. A lens unit according to claim 18, wherein said driving means adjusts exposure of said optical system.

27. A camera having a lens unit detachably mounted thereon, comprising:

a) driving means arranged to vary an operating state of said lens unit; and

b) control means for generating control information for controlling said driving means and for transmitting to said driving means said control information by adding thereto identifying information which indicates a signal processing method employed by said camera, said control means being arranged to transmit said control information to said lens unit at a predetermined period according to said signal processing method.

28. A camera according to claim 27, wherein said control means is provided with a memory for storing driving information for said driving means and is arranged to control said driving means by selecting driving information for said driving means from among the contents of said memory according to said control information.

29. A camera according to claim 28, wherein said driving information indicates a driving speed to be employed by said driving means.

30. A camera according to claim 29, wherein said driving means includes a motor for varying an optical characteristic of said lens unit and is arranged to control said motor by a pulse width modulation (PWM) signal on the basis of said control information and in synchronism with the periodicity of said control information signal.

31. A camera according to claim 30, wherein said control means is arranged to control an on-period of said PWM signal in accordance with a characteristic of said control information signal.

32. A camera according to claim 31, wherein said identifying information indicates a vertical synchronizing signal frequency of a TV signal system employed by said camera.

33. A camera according to claim 32, wherein said control means is operative to transmit said control information in synchronism with the vertical synchronizing signal frequency of a TV signal employed by said camera.

34. A camera according to claim 33, wherein said driving means adjusts focus of said lens unit.

35. A camera according to claim 27, wherein said driving means adjusts exposure of said lens unit.

36. A camera according to claim 35, wherein said driving means includes an integrating circuit which integrates an image signal in a predetermined periodicity to detect the quantity of incident light, and wherein said control means is arranged to vary a cut-off frequency of said integrating circuit in accordance with a discrimination made by discriminating means.

37. A camera according to claim 36, wherein said control means discriminates the periodicity of a vertical synchronizing signal of a TV signal processed in said camera and is operative to transmit said control information in synchronism with the periodicity of said vertical synchronizing signal.

38. A camera system having a camera body and a lens unit which is detachably mountable on said camera body, comprising:

a) driving means for varying the state of an optical system of said lens unit;

b) transmission means for transmitting, from said camera body to said lens unit, driving information required for varying a state of said optical system and identifying information corresponding to a signal processing method employed in said camera body; and

c) control means for controlling and varying an operating state of said optical system of said lens unit on the basis of said driving information and to vary a control characteristic of said driving means on the basis of said identifying information.

39. A camera system according to claim 38, wherein said transmission means is arranged to transmit said information in synchronism with a vertical synchronizing signal frequency of a TV signal processed in said camera body.

40. A camera system according to claim 39, wherein said identifying information is a signal indicating the vertical synchronizing signal frequency of said TV signal.

41. A camera system according to claim 40, wherein said driving means adjusts focus of said lens unit, and wherein said control means controls a driving speed of said driving means according to said identifying information.

42. A system according to claim 40, wherein said driving means adjusts exposure of said lens unit, and wherein said control means controls, according to said identifying information, a time constant of an integrating means for detecting the quantity of incident light.