Photoexposure device
Abstract
Abstract A DEVICE FOR EXPOSING LINES ON A SHEET OF PHOTOSENSITIVE MATERIAL CONSISTS OF A PROJECTOR WHICH PROJECTS A MOVING SPOT OF LIGHT ONTO THE MATERIAL. CORRECT EXPOSURE, DESPITE VARIATIONS IN THE SPEED OF THE SPOT, IS MAINTAINED BY PRODUCING TWO SIGNALS RELATED, RESPECTIVELY, TO THE VELOCITY OF THE SPOT AND ITS INTENSITY AND BY COMBINING THESE TWO SIGNALS TO PRODUCE AN ERROR SIGNAL USED TO CONTROL THE SPOT INTENSITY. THE INTENSITY CONTROL CONSISTS OF A MEANS FOR REGULATING THE POWER SUPPLIED TO AN INCANDESCENT LAMP USED AS THE LIGHT SOURCE OR OF A VARIABLE DENSITY FILTER POSITIONED IN THE PATH OF THE LIGHT BEAM FORMING THE LIGHT SPOT. THE FILTER IS ONE HAVING A LINEAR TRANSMITTANCE GRADIENT SO AS TO OBTAIN GOOD PERFORMANCE OF THE CLOSED SERVO LOOP BY MAINTAINING A SUBSTANTIALLY CONSTANT LOOP GAIN AT ALL THE POSITIONS OF THE FILTER. TWO STEPPING MOTORS ARE PROVIDED FOR DRIVING THE PROJECTOR IN TWO COORDINATE DIRECTIONS RELATIVE TO THE PHOTOSENSITIVE MATERIAL TO OBTAIN MOVEMENT OF THE LIGHT SPOT, AND THE VELOCITY SIGNAL USED IN THE SERVO LOOP FOR CONTROLLING THE SPOT INTENSITY IS DERIVED FROM THE INPUT PULSES TO THESE MOTORS.
Inventors
- 👤 Heinz Joseph Gerber
- 👤 Ronald B Webster
Bibliographic Details
Claims Analysis
Total Claims: 0References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-10-04 | 1975-04-05 | 1975-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-04 | 1979-04-05 | 1979-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-04 | 1983-04-05 | 1983-10-05 | $7700.00 | Window Closed / Lapsed |