ADAPTIVE ILLUMINATION SOURCE INTENSITY CONTROL DEVICE

• US 3,738,242 A
• Filed: 06/11/1971
• Issued: 06/12/1973
• Est. Priority Date: 06/11/1971
• Status: Expired due to Term

• Current Assignee: Barry T. Lee, Gilbert P. Hyatt, Gunther W. Wimmer
• Original Assignee: Barry T. Lee, Gilbert P. Hyatt, Gunther W. Wimmer
• Inventors: Lee, Barry T., Wimmer, Gunther W., Hyatt, Gilbert P.
• Primary Examiner(s): Greiner, Robert P.
• Application Number:
  US05/152,105
• Time in Patent Office: 732 Days
• Field of Search: 95/12,1 355/67,68,69
• US Class Current: 396/548
• CPC Class Codes: B41B 21/08 Light sources; Devices associated therewith, e.g. control devices
• CPC Class Codes: G06K 15/225 using optical plotters

Abstract

A control system is provided for precisely controlling the intensity of an illumination source which forms part of a photomechanical system. The control system enables the intensity of the illumination source to be controlled in accordance with the characteristics of the recording medium (photo material), the relative motion between the recording medium and the illumination source, the image to be formed on the recording medium, the dynamics of the system causing the relative motion between the source and the recording medium, variations in the illumination source and over their life, and the illumination source dynamics.

Claims

1. In a system for selectively exposing an illumination sensitive medium with controlled illumination including an illumination means for providing the controlled illumination and a machine for providing relative motion between said medium and said illumination means, the improvement comprising;

an illumination source means in said illumination means for generating said illumination, said illumination source means responsive to at least one electrical energization signal for controlling the intensity of said controlled illumination, an illumination control means for providing said electrical energization signal, said illumination control means responsive to said illumination and providing said electrical energization signal in response thereto.

2. The system of claim 1 wherein said illumination control means includes a closed loop servo control with a sensing means responsive to the controlled illumination for generating an illumination feedback signal, said servo control responsive to said illumination feedback signal and providing said electrical energizing signal in response thereto.

3. The system of claim 2 wherein said illumination control means is responsive to a selected spectrum region of the controlled illumination and said electrical energization signal is related to said selected spectrum region of the controlled illumination.

4. The system of claim 2 wherein said system is a photo-optical system, said medium is a photographic medium, and said illumination means is a photohead for providing visible illumination to selectively expose said medium.

5. The system of claim 2 wherein said closed loop servo control includes a dynamic compensation network for controlling the dynamic response of said electrical energization signal, said illumination source responsive to said electrical energization signal and providing illumination with controlled dynamics in response thereto.

6. The system of claim 5 wherein the relative motion provided by said machine has a characteristic dynamic response and said dynamic compensation in said illumination control means is selected to match the dynamic response of said illumination means to the dynamic response of the relative motion provided by said machine.

7. The system of claim 4 wherein said illumination source means is an incandescent lamp, said electrical energization signal energizes said lamp to generate the controlled illumination, said sensing means is a photocell responsive to a selected spectrum region of the controlled illumination, and said feedback signal is related to the intensity of the selected spectrum region of the controlled illumination.

8. The system of claim 2 wherein said illumination control means is responsive to an illumination command signal and generates said electrical energization signal in response thereto, said closed loop servo control includes a high gain servo loop to provide the commanded illumination with the reduction of at least one illumination error.

9. The system of claim 8 wherein said error is a time related change in the response of said illumination source means to said electrical energization signal.

10. The system of claim 8 wherein said error is a non-linearity in the response of said illumination source means to said electrical energization signal.

11. The system of claim 1 wherein said illumination control means is responsive to at least one relative motion related command signal for commanding said controlled illumination.

12. The system of claim 1 whErein said illumination control means is responsive to at least one command signal related to an image configuration of said illumination for commanding said said controlled illumination.

13. The system of claim 1 wherein said illumination control means is responsive to at least one bias command signal for commanding said controlled illumination.

14. The system of claim 1 further comprising a digital command means for providing at least one digital illumination command signal to said illumination control means, said illumination control means being operationally connected to said digital command means to provide the controlled illumination in response to at least one of said digital command signals.

15. The system of claim 14 wherein said digital command means is a stored program digital computer means responsive to system input commands and providing said at least one digital illumination command signal in response thereto.

16. The system of claim 15 wherein said computer means is responsive to a stored program for processing system input commands and providing said digital illumination command in response thereto.

17. The system of claim 16 wherein said computer means is responsive to a stored program for accessing a selected digital illumination command from a plurality of digital illumination commands stored therein and for providing said selected digital illumination command to said illumination control means.

18. The system of claim 17 wherein said system input commands define at least one aperture to control the configuration of said illumination image, wherein said stored program provides for the selection of said aperture and wherein said selected digital illumination command provides for controlled illumination related to said selected aperture.

19. The system of claim 1 wherein said illumination means provides controlled illumination that has a non-linear relationship with said electrical energizing signal, said illumination control means is responsive to a command signal and generates said electrical energizing signal to provide controlled illumination that has a linear relationship with said command signal.

20. In a system for converting numerical representations to illumination responsive representations, the combination comprising:

command means for generating an illumination command signal related to a desired intensity of illumination;

illumination source means for providing illumination at a variable intensity related to said illumination command signal in response to an electrical energizing signal applied thereto;

sensing means operationally coupled to said illumination source means for sensing a condition related to illumination provided by said illumination source means and providing an illumination signal in response thereto; and

control means connected to receive the command signal and the illumination signal for precisely controlling the illumination in accordance with the command signal by providing the illumination source means with said electrical energizing signal.

21. The system of claim 20 wherein said system is a photo-optical system and said illumination source means is part of a photohead means for providing visible illumination to selectively expose a photographic medium.

22. In a system for selectively exposing an illumination sensitive medium with controlled illumination including an illumination means for providing said controlled illumination and a machine for providing relative motion between said medium and said illumination means, the improvement comprising;

an illumination source means included said illumination means for generating said illumination, said illumination source means responsive to at least one electrical control signal for controlling the intensity of said controlled illumination;

an illumination sensor generating an illumination intensity signal in response to said controlled illumination;

means for generating a command signal indicative of a desIred exposure of said medium;

means for generating a velocity signal indicative of relative motion between said medium and said illumination means; and

an llumination control system connected to provide said electrical control signal in response to said intensity signal, command signal and velocity signal to expose said medium in accordance with said command signal.

23. The system of claim 22 wherein said illumination control system includes a closed loop servo control providing dynamic compensation to control the dynamic response of said electrical control signal.

24. The system of claim 23 wherein the relative motion provided by said machine has a characteristic dynamic response and said dynamic compensation in said illumination control system is selected to match the dynamic response of said illumination source to the dynamic response of the relative motion provided by said machine.

25. An illumination control system comprising:

an illumination means positioned to illuminate an illumination sensitive medium;

means for providing relative motion between an illumination sensitive medium and said illumination means, said relative motion having a particular dynamic response characteristic;

means for sensing a condition related to said illumination and generating an illumination signal in response thereto;

means for generating a command signal related to desired illumination; and

a control system responsive to the illumination signal and the command signal for generating an electrical control signal to control said illumination, said control signal having a dynamic response characteristic substantially matching the dynamic response characteristic of the relative motion providing means to the dynamic response of the illumination means.

26. The illumination system as set forth in claim 25 above wherein said control system further includes a biasing circuit for generating at least a minimum electrical control signal related to a response threshold to achieve greater dynamic response.

27. The illumination system as set forth in claim 25 above wherein the control system further includes a pulse generating circuit inducing a change in the control signal to generate a rapid dynamic response for providing substantially uniform exposure of the medium during a period of acceleration of the relative motion providing means.

28. A system providing precisely controlled illumination of an illumination receiving medium comprising:

an illumination means positioned to illuminate the illumination receiving medium with illumination related to an electrical control signal;

means for providing relative motion between the medium and the illumination means and generating a motion condition indicative of said relative motion;

means for generating an exposure condition indicative of a desired exposure of the medium to said illumination;

means for sensing at least one component of illumination and generating an illumination condition indicative thereof; and

an illumination control system including means responsive to the exposure condition and the motion velocity condition for generating an illumination command condition indicative of the product thereof and a high gain servo generating an electrical control signal for the illumination means in response to a difference between the illumination command condition and the illumination condition.

29. In a system for selectively exposing an illumination sensitive medium with controlled illumination in response to at least one illumination command signal including a machine for providing relative motion between said medium and an illumination source, the improvement comprising:

illumination source means providing said controlled illumination in response to an illumination control signal;

transducer means selectively responsive to at least one particular spectrum of said illumination and providing a feedback signal in response thereto; and

illumination control means for providing an illumination control signal in response to the combination of at least one illumination command signal and said feedback signal.

30. The system of claim 29 wherein said illumination control means includes a closed loop servo control having a high gain servo loop to control the commanded illumination, said high gain servo loop providing for the reduction of at least one error of said commanded illumination.

31. In a system for selectively exposing an illumination sensitive medium with controlled illumination including an illumination means for providing said controlled illumination and a machine for providing relative motion between said medium and said illumination means, the improvement comprising:

control means responsive to the controlled illumination for controlling the illumination means to reduce differences between the controlled illumination and desired illumination.

32. The system of claim 31 wherein said control means includes a closed loop servo for reducing deviations from a linear relationship as the controlled illumination is varied in response to a selected independent variable.

33. The system of claim 31 further comprising a command means for providing at least one illumination command signal wherein said illumination command signal is an illumination bias related to a threshold condition of said illumination means.

34. The system of claim 33 wherein said illumination means includes an incandescent bulb and said threshold condition is the illumination command condition at which said bulb provides sufficient illumination to effectively expose said medium.

35. The system of claim 31 further comprising a command means for providing at least one illumination command condition wherein said illumination command condition is a transient condition provided in response to a system condition.

36. The system of claim 35 wherein said transient condition is a pulse and said system condition is the start of an exposure, said illumination means responsive to said transient condition and providing for a rapid change in illumination in response thereto.

37. In a system for selectively exposing an illumination sensitive medium with controlled illumination including an illumination means for providing said controlled illumination and a machine for providing relative motion between said medium and said illumination means, the improvement comprising:

an illumination control means responsive to a plurality of illumination command conditions and providing a non-linear illumination control condition in response thereto;

said illumination means operationally connected to said illumination control means and responsive to said illumination control condition for providing said controlled illumination in response thereto.

38. The system of claim 37 wherein said non-linearity is related to the product of a first illumination command condition and a second illumination command condition.

39. The system of claim 38 wherein said first illumination command condition is related to a first condition affecting the response of said medium to said illumination and said second illumination command condition is related to a second condition affecting the response of said medium to said illumination.

40. The system of claim 39 wherein said first condition is the configuration of the illumination image and said second condition is the velocity of said relative motion.

41. The system of claim 38 wherein said illumination control means includes a digital to analog converter responsive to said first illumination command condition in digital signal form and said second illumination command condition in analog signal form and provides said illumination control condition in analog signal form in response thereto.

42. The system of claim 37 wherein said non-linearity is related to a time related change of at least one illumination command condition.

43. The system of claim 42 wherein said non-linearity controls the dynamiC response of said illumination means to said illumination command condition.

44. The system of claim 43 wherein said non-linearity provides a condition that matches the dynamic response of the illumination of said illumination means to the dynamic response of the relative motion of said machine in response thereto.

45. In a system for selectively exposing an illumination sensitive medium with controlled illumination including an illumination means for providing said controlled illumination and a machine for providing relative motion between said medium and said illumination means, the improvement comprising:

a translation control means for providing said relative motion in response to a translation command condition;

an illumination control means for controlling said illumination in response to an illumination command condition;

compensation means for controlling the dynamic response of said illumination means in relation to said illumination command condition.

46. The system of claim 45 wherein said compensation means provides for the matching of the dynamic response of said illumination means to the dynamic response of said machine.

47. The system of claim 45 wherein said translation control means includes a closed loop servo means for providing a velocity command signal;

said machine responsive to said velocity command signal and providing dynamic motion in response thereto;

said illumination control means responsive to said velocity command signal and providing dynamic illumination in response thereto;

said compensation means providing for matching said dynamic illumination to said dynamic motion.

48. The system of claim 47 wherein said velocity command signal is a servo steady state position error velocity command signal with the characteristic of anticipating machine dynamic motion.

49. In a system for selectively exposing an illumination sensitive medium with controlled illumination including an illumination means for providing said controlled illumination and a machine for providing relative motion between said medium and said illumination means, the improvement comprising;

control means including a stored program digital computer processor means for processing system conditions under stored program control and providing at least one command signal in response thereto, said computer means being responsive to an illumination stored program routine and providing at least one illumination command in response thereto, and said illumination means being operationally connected to said computer means and responsive to said at least one illumination command for controlling said illumination.

50. The system of claim 49 wherein said computer means is responsive to a translation stored program routine and provides at least one translation command signal in response thereto, said machine means being operationally connected to said computer means and responsive to said at least one translation command signal for providing said relative motion.

51. The system claim 49 wherein said computer means includes a memory for storing digital information including illumination commands, wherein said control means includes means for controlling said illumination in response to a selected illumination command and means for selecting an illumination image configuration, and wherein said computer means operates under control of a stored program to access a selected illumination command from the memory in response to a selected illumination image, said selected illumination command indicating a desired illumination for the selected illumination image configuration.

52. In a system for selectively exposing an illumination sensitive medium with controlled illumination including an illumination means for providing said controlled illumination in a selected image configuration, a machine for providing relative motion between said medium and said illumination means, and control means for controlling said illumination in response to an illuminaTion command signal, the improvement comprising:

stored program computer processor means for processing system information under stored program control to generate at least one illumination command signal, said computer means being responsive to a rotation stored program routine to generate at least one image rotation command signal, means for generating a rotation control signal in resposnse to the image rotation command signal; and

image rotation means connected to said illumination means for rotating said image configuration in response to the rotation control signal.

53. An illumination control system for exposing a medium to controlled illumination comprising:

stored program digital computer means for processing digital information under program control in response to input commands, said computer means generating a first command signal for controlling a servo system to provide relative movement between a medium and an illuminated image projected thereon, generating a second velocity signal indicative of relative velocity between the medium and projected image commanded by the first command signal, generating a third illumination command signal indicative of a desired illumination condition and generating a fourth illumination command signal representing the product of the second velocity signal and third illumination command signal;

an illumination system for projecting an illuminated image on a medium;

a servo system responsive to the first command signal for providing relative motion between the medium and the image projected thereon along at least one axis;

means responsive to a condition dependent upon an actual illumination condition and generating a fifth illumination feedback signal indicative of said actual illumination condition; and

control means operating in response to said fifth illumination feedback signal and said fourth illumination command signal and generating an electrical control signal, said electric control signal controlling illumination from the illumination system to maintain a desired relationship between the fifth illumination feedback signal and said fourth illumination command signal.

54. An illumination control system for exposing a medium to controlled illumination comprising:

stored program digital computer means responsive to input commands and a velocity condition, for generating an intensity command indicating a proper illumination intensity for desired exposure of the medium;

illumination means for projecting an illuminated image on a medium, said image being illuminated by a source in response to an electrical energization signal;

means for moving the projected image with respect to the medium and for providing the computer means with a velocity comdition indicative of relative motion between the medium and the image projected thereon;

means for sensing the intensity of illumination from the source and for generating an intensity feedback signal indicative thereof; and

means responsive to the intensity command and intensity feedback signal for providing the source with an electricl energization signal causing the intensity of illumination to be controlled to maintain the desired relationship between the illumination feedback signal and illumination command.

55. In a system for selectively exposing an illumination sensitive medium with controlled illumination including an illumination means for providing said controlled illumination and a machine for providing relative motion between said medium and said illumination means, the improvement comprising, an electrical means for controlling said illumination including a closed loop means responsvie to said illumination and providing at least one electrical control signal to electrically control said illumination.