Linear densitometer
Abstract
Abstract THE PRESENT INVENTION IS DIRECTED TO AN OPTICAL DENSITOMETER WHICH PROVIDES A DIRECT LINEAR READING OF OPTICAL DENSITY FROM A NON-LINEAR INPUT OF LIGHT INTENSITY. THE PRESENT INVENTION USES A BRIDGE MEASURING CIRCUIT INCLUDING A PHOTORESISTIVE CELL WHICH HAS A NON-LINEAR CHARACTERISTIC TO RPOVIDE A FIRST ORDER COMPENSATION FOR THE NON-LINEAR CHARACTER OF THE INPUT LIGHT INTENSITY TO THE PHOTOSENSITIVE CELL AND, IN ADDITION, USES A SEMICONDUCTOR DEVICE SUCH AS A SILICON-CONTROLLED RECTIFIER IN COMBINATION WITH THE BRIDGE MEASURING CIRCUIT TO CONTROL THE CURRENT FLOWING THROUGH AN OUTPUT METER AND WITH THE SEMICONDUCTOR DEVICE, SUCH AS THE SILICON-CONTROLLED RECTIFIER, PROVIDING A SECOND ORDER COMPENSATION SO THAT THE OUTPUT INDICATION IS AN EXTREMELY ACCURATE DIRECT LINEAR READING OF OPTICAL DENSITY.
Inventors
- 👤 Howard L Monell
Bibliographic Details
Claims Analysis
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-02-22 | 1974-08-24 | 1975-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-22 | 1978-08-24 | 1979-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-22 | 1982-08-24 | 1983-02-23 | $7700.00 | Window Closed / Lapsed |