US3709615A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Integrating light meter with movable meter mechanism
Assignee: Calumet Photographic Inc
•
Filing: 1969-02-28
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Granted: 1973-01-09
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Expires: 1989-02-28
Abstract
Abstract An integrating light meter with a circuit which develops a signal representing the logarithm of the light being measured and utilizes a display having a linear f-number scale. The meter has two ranges, provided by physically moving the meter mechanism with relation to the scale indicia so that the range of movement of the pointer encompasses a different portion of the scale. The sensitivity of the meter is changed between ranges by a mask with an aperture therein which limits the light to the photocell.
Inventors
- 👤 E Bryll
- 👤 T Blakeslee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 12:25
CPC Classifications
G; G01; G01J; G01J1/00; G01J1/42; G01J1/4209; G01J1/4214
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
106 words
A light meter, comprising: a photocell for sensing received light; a signal translating circuit connected with the photocell, for developing an output signal proportional to the logarithm of the light sensed by the photocell; a meter connected with said circuit and having a moving indicator with limited excursion for providing an indication of said output signal; a continuous scale for said meter indicator having an extent greater than the excursion of the indicator; means for moving the meter relative to said scale; and means for controlling the sensitivity of the meter indication to light in accordance with the position of said meter relative to said scale.
Claim 2
Dependent Claim
106 words
A light meter, comprising: a photocell for sensing received light; a signal translating circuit connected with the photocell, for developing an output signal proportional to the logarithm of the light sensed by the photocell; a meter connected with said circuit and having a moving indicator with limited excursion for providing an indication of said output signal; a continuous scale for said meter indicator having an extent greater than the excursion of the indicator; means for moving the meter relative to said scale; and means for controlling the sensitivity of the meter indication to light in accordance with the position of said meter relative to said scale.
Claim 3
Dependent Claim
30 words
The light meter of claim 1 in which the sensitivity of the meter indication is controlled by an aperture plate movable with relative movement between the meter and the scale.
Claim 4
Dependent Claim
25 words
The light meter of claim 1 in which said scale is an f-number scale adjustable with respect to said meter in accordance with film speed.
Claim 5
Dependent Claim
138 words
A photographic light meter, comprising: a housing; a photocell in said housing for sensing received light; a light measuring circuit having an input connected with said photocell and an output; a meter connected with the output of said circuit and having a pivoted indicator with limited excursion; a continuous annular indicia scaLe on said housing having an angular extent greater than the excursion of said pivoted meter indicator; means mounting said meter for rotation on said housing between a first position in which the excursion of the indicator is related to one portion of said scale and a second position in which the excursion of the indicator is related to another portion of said scale; and means for controlling the sensitivity of the meter to light in accordance with the position of the meter relative to said scale.
Claim 6
Dependent Claim
138 words
A photographic light meter, comprising: a housing; a photocell in said housing for sensing received light; a light measuring circuit having an input connected with said photocell and an output; a meter connected with the output of said circuit and having a pivoted indicator with limited excursion; a continuous annular indicia scaLe on said housing having an angular extent greater than the excursion of said pivoted meter indicator; means mounting said meter for rotation on said housing between a first position in which the excursion of the indicator is related to one portion of said scale and a second position in which the excursion of the indicator is related to another portion of said scale; and means for controlling the sensitivity of the meter to light in accordance with the position of the meter relative to said scale.
Claim 7
Dependent Claim
62 words
The meter of claim 4 wherein the housing has an inlet opening through which the light sensed by the photocell is received, and the means for controlling the sensitivity of the meter includes a mask with an aperture therethrough movable with rotation of the meter to a location between the light inlet opening and the photocell in one position of the meter.
Claim 8
Dependent Claim
39 words
The light meter of claim 4 in which said indicia scale represents f-numbers and is rotatable on said housing to establish a relative position between the meter and indicia in accordance with the speed of film to be used.
Claim 9
Dependent Claim
27 words
The light meter of claim 6 in which the film speed indicia is on the housing and has a pointer associated with the rotatable f-stop indicia scale.
Claim 10
Dependent Claim
30 words
The light meter of claim 4 having a mask with an opening therein through which a portion of the indicia scale is visible, said mask being movable with said meter.
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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) | 1976-01-09 | 1976-07-10 | 1977-01-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-09 | 1980-07-10 | 1981-01-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-09 | 1984-07-10 | 1985-01-09 | $7700.00 | Window Closed / Lapsed |