US3658431A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photomicrographic exposure meter
Assignee: American Optical Corp
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Filing: 1970-06-01
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Granted: 1972-04-25
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Expires: 1990-06-01
Abstract
Abstract A photomicrographic exposure meter including a photocell to sense and register the light level of an in-focus specimen image and transmit the same to a light-level meter. In a mechanized nomogram having four scales, the independent parameters of film ASA rating and picture format are selected. The ASA and picture format dials are then locked into position with each other A light-level scale, which is locked to the ASA scale, is turned to a reading corresponding to that on the light-level meter. The exposure time is then read out of the instrument on the exposure time scale. The shutter on the photomicrographic camera is then set to correspond to the indicated exposure time.
Inventors
- 👤 James V Richards
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 12:44
CPC Classifications
G; G01; G01J; G01J1/00; G01J1/42; G01J1/4209; G01J1/4214
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
175 words
A photomicrographic exposure meter for use with a microscope including: a photocell adapted for communication with the optical path of a microscope, a light-level meter operatively connected with said photocell to indicate light level in said optical path, a calculator having four circular coaxial scales rotatable relative to a frame, the first of said scales bearing photomicrograph format parameters, the second of said scales bearing film ASA parameters, the third of said scales bearing light-level parameters, the fourth of said scales bearing exposure-time parameters, said first and fourth scales being fixed relative to each other and rotatable relative to said second and third scales, said second and third scales also being fixed relative to each other, means to engage said first and fourth scales with said second and third scales for rotation in unison, a reference point on said frame as to which said third lightlevel scale is positioned to duplicate the reading observed on said light-level meter, said fourth exposure time scale indicating at said reference point an exposure time for a photomicrographic camera.
Claim 2
Dependent Claim
175 words
A photomicrographic exposure meter for use with a microscope including: a photocell adapted for communication with the optical path of a microscope, a light-level meter operatively connected with said photocell to indicate light level in said optical path, a calculator having four circular coaxial scales rotatable relative to a frame, the first of said scales bearing photomicrograph format parameters, the second of said scales bearing film ASA parameters, the third of said scales bearing light-level parameters, the fourth of said scales bearing exposure-time parameters, said first and fourth scales being fixed relative to each other and rotatable relative to said second and third scales, said second and third scales also being fixed relative to each other, means to engage said first and fourth scales with said second and third scales for rotation in unison, a reference point on said frame as to which said third lightlevel scale is positioned to duplicate the reading observed on said light-level meter, said fourth exposure time scale indicating at said reference point an exposure time for a photomicrographic camera.
Claim 3
Dependent Claim
30 words
An exposure meter as defined in claim 1 in which said light-level meter has a plurality of sensitivities and said third light-level scale has a corresponding number of light-level ranges.
Claim 4
Dependent Claim
30 words
An exposure meter as defined in claim 1 in which said light-level meter is operatively connected to a circuit, said circuit including a photoresistor which is variable by said photocell.
Claim 5
Dependent Claim
209 words
An exposure meter for a photomicrographic camera including: a photocell adapted for communication with the optical path of a microscope, said photocell operatively connected to a photoresistor, a light-level meter operatively connected with said photocell to indicate light level in said optical path, means for varying the sensitivity of said light-level meter so as to correspondingly vary the range of its recorded parameter, means to vary the input voltage to said photoresistor, a calculator having four circular coaxial scales rotatable relative to a frame, the first of said scales bearing photomicrographic format parameters, the second of said scales bearing film ASA parameters, the third of said scales bearing light-level parameters, the fourth of said scales bearing exposure-time parameters, said first and fourth scales being fixed relative to each other and rotatable relative to said second and third scales, said second and third scales also being fixed relative to each other, means to engage said first and fourth scales with said second and third scales for rotation in unison, a reference point on said frame as to which said third light-level scale is positioned to duplicate the reading observed on said light-level meter, said fourth exposuRe time scale indicating at said reference point an exposure time for a photomicrographic camera.
Claim 6
Dependent Claim
209 words
An exposure meter for a photomicrographic camera including: a photocell adapted for communication with the optical path of a microscope, said photocell operatively connected to a photoresistor, a light-level meter operatively connected with said photocell to indicate light level in said optical path, means for varying the sensitivity of said light-level meter so as to correspondingly vary the range of its recorded parameter, means to vary the input voltage to said photoresistor, a calculator having four circular coaxial scales rotatable relative to a frame, the first of said scales bearing photomicrographic format parameters, the second of said scales bearing film ASA parameters, the third of said scales bearing light-level parameters, the fourth of said scales bearing exposure-time parameters, said first and fourth scales being fixed relative to each other and rotatable relative to said second and third scales, said second and third scales also being fixed relative to each other, means to engage said first and fourth scales with said second and third scales for rotation in unison, a reference point on said frame as to which said third light-level scale is positioned to duplicate the reading observed on said light-level meter, said fourth exposuRe time scale indicating at said reference point an exposure time for a photomicrographic camera.
References Cited (Backward Citations)
US2533489A
Cited
US3488125A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-04-25 | 1975-10-25 | 1976-04-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-04-25 | 1979-10-25 | 1980-04-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-04-25 | 1983-10-25 | 1984-04-25 | $7700.00 | Window Closed / Lapsed |