US3653772A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Two lamp light comparison type densitometer
Assignee: Eastman Kodak Co
•
Filing: 1969-08-19
•
Granted: 1972-04-04
•
Expires: 1989-08-19
Abstract
Abstract Two lamps are lighted alternately at controlled intensities, both lamps illuminate a common sensor and the light path from one lamp includes the density to be measured. When a minimum differential is detected, the ratio of the currents in the lamps is a function of the density being measured and current in either one or both lamp is servo-controlled to minimize the differential. The current or voltage ratios are converted and read out as density values.
Inventors
- 👤 Ralph L Berge
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:02
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/25; G01N21/256; G01J; G01J1/00; G01J1/10; G01J1/20; G01J1/28; G01J1/30
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
134 words
A comparison densitometer comprising, in combination: a sensing means for comparing light of a sample with that of a standard; means including one electric lamp for illuminating said sensor with reference light; means including another electric lamp; optical means for illuminating said sensor with sample light for comparison with such reference light, said optical means including light impervious shade means disposed between said lamps; lens means for concentrating the sample light on a circuited portion of the sample, circuit means for electrically energizing said lamps alternately from a common source of supply at a rate sufficiently low to turn the light of said lamps on and off; and an internally mirrored sphere having disposed therein, said sensor and one of said lamps, said sphere having an opening for light originating in the other lamp.
Claim 2
Dependent Claim
134 words
A comparison densitometer comprising, in combination: a sensing means for comparing light of a sample with that of a standard; means including one electric lamp for illuminating said sensor with reference light; means including another electric lamp; optical means for illuminating said sensor with sample light for comparison with such reference light, said optical means including light impervious shade means disposed between said lamps; lens means for concentrating the sample light on a circuited portion of the sample, circuit means for electrically energizing said lamps alternately from a common source of supply at a rate sufficiently low to turn the light of said lamps on and off; and an internally mirrored sphere having disposed therein, said sensor and one of said lamps, said sphere having an opening for light originating in the other lamp.
Claim 3
Dependent Claim
52 words
The invention as defined by claim 1, in which the lamp within the sphere produces the reference light, and the lamp outside of the sphere produces the sample light which passes through such selected portion of the sample and then through such opening in the sphere on its way toward said senses.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-04-04 | 1975-10-04 | 1976-04-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-04-04 | 1979-10-04 | 1980-04-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-04-04 | 1983-10-04 | 1984-04-04 | $7700.00 | Window Closed / Lapsed |