US3868183A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Exposure control system
Assignee: Graphic Arts Manufacturing Co Inc
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Filing: 1973-07-16
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Granted: 1975-02-25
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Expires: 1993-07-16
Abstract
Abstract It the exposure of photographic mediums, factors such as highlight density, shadow tone density, screen range, and excess optical density are of significance in controlling of the exposure. The apparatus of the present invention is a control system utilizing a bridge circuit to relate these four qualities and further includes improvements in the operation of the timing circuitry. The apparatus is responsive to selected inputs.
Inventors
- 👤 Warren Childers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 15:35
CPC Classifications
G; G03; G03B; G03B27/00; G03B27/72; G03B27/80; G01; G01J; G01J1/00; G01J1/42
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
115 words
An apparatus for controlling the exposure of a photographic medium to accept an image source which has shadow tones and highlight density values which differ from one another through the use of a screen having a given screen range, comprising: computing means for receiving multiple inputs representative of at least two of three variables which are highlight density, shadow tone density, and screen range, said means determining the remaining of said variables from the two variables input thereto and relating an exposure time to the value of the variables; and, first means connected to said computing means for controlling the integral of light exposure of a photographic medium in response to the variables supplied thereto.
Claim 2
Independent Claim
115 words
An apparatus for controlling the exposure of a photographic medium to accept an image source which has shadow tones and highlight density values which differ from one another through the use of a screen having a given screen range, comprising: computing means for receiving multiple inputs representative of at least two of three variables which are highlight density, shadow tone density, and screen range, said means determining the remaining of said variables from the two variables input thereto and relating an exposure time to the value of the variables; and, first means connected to said computing means for controlling the integral of light exposure of a photographic medium in response to the variables supplied thereto.
Claim 3
Dependent Claim
83 words
The apparatus of claim 1 wherein said computing means includes a resistive bridge circuit for relating the variables to one another and wherein said bridge circuit inicludes variable elements which are adjustable to cause said bridge circuit to seek a null condition when the three variables have been determined and said bridge circuit is operatively connected to an RC timing circuit to control its timed operation, and said first means includes a lamp control circuit adapted to be connected to an exposure lamp.
Claim 4
Dependent Claim
38 words
The apparatus of claim 2 wherein said computing means solves the equation S H + R, where S represents shadow tone density, H represents highlight density and R represents screen range, all defined for a positive image source.
Claim 5
Dependent Claim
34 words
The apparatus of claim 2 wherein said computing means has three inputs representative of four variables where the additional variable is excess density and said computing means determines the remaining of the four variables.
Claim 6
Dependent Claim
41 words
The apparatus of claim 4 wherein said computing means is a bridge circuit having one leg which is variable to represent one of the four variables, and having another leg which includes three variable components to represent the remaining three variables.
Claim 7
Independent Claim
155 words
An apparatus for controlling the exposure of a photographic medium in a process camera apparatus which includes a light source turned on for an interval to expose a photographic medium in the camera, comprising: light sensitive means exposed to light coterminous in duration to the exposure of a photographic medium in a process camera by a light source; RC timing circuit means for storing a charge to a predetermined level; a discharge path in said RC timing circuit means, said discharge path incorporating said light sensitive means in a manner such that the rate of discharge of said RC timing circuit means is determined at least in part by said light sensitive means; means connected to said RC timing circuit means for determining discharge thereof to a predetermined level, said means forming an output signal so indicating; and, means responsive to the output signal for terminating operation of a light source in the process camera.
Claim 8
Independent Claim
155 words
An apparatus for controlling the exposure of a photographic medium in a process camera apparatus which includes a light source turned on for an interval to expose a photographic medium in the camera, comprising: light sensitive means exposed to light coterminous in duration to the exposure of a photographic medium in a process camera by a light source; RC timing circuit means for storing a charge to a predetermined level; a discharge path in said RC timing circuit means, said discharge path incorporating said light sensitive means in a manner such that the rate of discharge of said RC timing circuit means is determined at least in part by said light sensitive means; means connected to said RC timing circuit means for determining discharge thereof to a predetermined level, said means forming an output signal so indicating; and, means responsive to the output signal for terminating operation of a light source in the process camera.
Claim 9
Dependent Claim
37 words
The apparatus of claim 6 wherein said RC timing circuit means is discharged at least twice and wherein said last named means requires at least two of the output signals to exercise control over the light source.
Claim 10
Dependent Claim
20 words
The apparatus of claim 6 wherein said RC timing circuit means is duplicated and said duplicate circuits are operated alternately.
Claim 11
Dependent Claim
16 words
The apparatus of claim 8 wherein said duplicate RC circuit means are alternately charged and discharged.
Claim 12
Dependent Claim
24 words
The apparatus of claim 8 including a digital counter means which stores the output signals which are provided thereto in the form of pulses.
Claim 13
Independent Claim
100 words
An apparatus for controlling the exposure of a photographic medium to accept a photographic image from an image source which comprises: a light responsive means constructed and arranged to receive light which falls on such a photographic medium; a pair of adjustable capacitive networks adapted to receive and hold a charge thereon from a charging source; and, resistive circuit means connected to said light responsive means and to said pair of capacitive networks for at least partially discharging first one of said pair and thereafter the other of said pair which discharge represents the light falling on the photographic medium.
Claim 14
Independent Claim
100 words
An apparatus for controlling the exposure of a photographic medium to accept a photographic image from an image source which comprises: a light responsive means constructed and arranged to receive light which falls on such a photographic medium; a pair of adjustable capacitive networks adapted to receive and hold a charge thereon from a charging source; and, resistive circuit means connected to said light responsive means and to said pair of capacitive networks for at least partially discharging first one of said pair and thereafter the other of said pair which discharge represents the light falling on the photographic medium.
Claim 15
Dependent Claim
20 words
The apparatus of claim 11 including means for charging one of said pair and then the other of said pair.
Claim 16
Dependent Claim
20 words
The apparatus of claim 11 including a counter means for counting repetition of discharging of said pair of capacitive networks.
Claim 17
Dependent Claim
26 words
The apparatus of claim 13 including a switch means for controlling discharge of said pair, and wherein said switch means is connected to said counter means.
Claim 18
Dependent Claim
28 words
The apparatus of claim 11 including a switch means connected to said pair of capacitive networks for selectively and controllably altering the capacitive value of said capacitive networks.
Claim 19
Independent Claim
118 words
An apparatus for controlling the exposure of a photographic medium to accept a photographic image from an image source which comprises: a light responsive means constructed and arranged to receive light which falls on such a photographic medium; a pair of adjustable capacitive networks adapted to receive and hold a charge thereon from a charging source; means for first connecting one of said pair and thereafter the other of said pair to said light responsive means, and wherein said pair are adapted to be adjusted to differing capacitive values representing differing assigned values of time units of exposure; and, means operatively connected to said capacitive networks for controlling the time integral of light falling on a photographic medium.
Claim 20
Independent Claim
118 words
An apparatus for controlling the exposure of a photographic medium to accept a photographic image from an image source which comprises: a light responsive means constructed and arranged to receive light which falls on such a photographic medium; a pair of adjustable capacitive networks adapted to receive and hold a charge thereon from a charging source; means for first connecting one of said pair and thereafter the other of said pair to said light responsive means, and wherein said pair are adapted to be adjusted to differing capacitive values representing differing assigned values of time units of exposure; and, means operatively connected to said capacitive networks for controlling the time integral of light falling on a photographic medium.
References Cited (Backward Citations)
US3542470A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-02-24 | 1978-08-26 | 1979-02-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-24 | 1982-08-26 | 1983-02-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-24 | 1986-08-26 | 1987-02-25 | $7700.00 | Window Closed / Lapsed |