Patent US3699861A successfully refreshed from Google Patents.
US3699861A
Expired / Lapsed
US
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Flash synchronization circuit for sequential firing of an array of flashbulbs
Assignee: Polaroid Corp
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Filing: 1969-07-24
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Granted: 1972-10-24
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Expires: 1989-07-24
Abstract
Abstract In a flash synchronization circuit, an array of flashbulbs are fired sequentially in synchronism with sequential actuations of the shutter mechanism. The shutter mechanism is opened and closed by electromagnets driven by Schmitt triggers. The sequential firing of the flashbulbs is controlled in response to signals derived from the Schmitt triggers and generated by the electromagnets.
Inventors
- 👤 John P Burgarella
- 👤 Seymour Ellin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:50
CPC Classifications
G; G03; G03B; G03B9/00; G03B9/70; H; H05; H05B; H05B41/00; H05B41/14; H05B41/30
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
173 words
A flash synchroNization circuit for synchronizing the sequential firing of a plurality of flashbulbs, grouped in an array, with sequential actuations of a camera shutter mechanism comprising: a firing circuit for firing said flashbulbs in sequence in response to firing signals applied thereto in sequence, firing at least one of said flashbulbs in response to each applied firing signal, electronic circuit means having a fixed circuit configuration, having first and second electrical states which are at least semistable, being unstable between said first and second electrical states, and being operable to switch between said first and second states in response to applied threshold signal levels, said shutter mechanism including means to open and close such shutter to define an exposure interval in a predetermined timed relationship with the switching of said electronic circuit means from said first state to said second state, said electronic circuit means generating a firing signal and applying such firing signal to said firing circuit when said electronic circuit means switches from said first state to said second state.
Claim 2
Dependent Claim
173 words
A flash synchroNization circuit for synchronizing the sequential firing of a plurality of flashbulbs, grouped in an array, with sequential actuations of a camera shutter mechanism comprising: a firing circuit for firing said flashbulbs in sequence in response to firing signals applied thereto in sequence, firing at least one of said flashbulbs in response to each applied firing signal, electronic circuit means having a fixed circuit configuration, having first and second electrical states which are at least semistable, being unstable between said first and second electrical states, and being operable to switch between said first and second states in response to applied threshold signal levels, said shutter mechanism including means to open and close such shutter to define an exposure interval in a predetermined timed relationship with the switching of said electronic circuit means from said first state to said second state, said electronic circuit means generating a firing signal and applying such firing signal to said firing circuit when said electronic circuit means switches from said first state to said second state.
Claim 3
Dependent Claim
66 words
A flash synchronization circuit as recited in claim 1 wherein said circuit means controls the energization of an electrical coil electromagnetically acting on said shutter mechanism to effect a regulation thereof, said electronic circuit means de-energizing said coil upon switching from said first state to said second state, said firing signals each comprising the pulse that is generated by said coil when said coil is de-energized.
Claim 4
Dependent Claim
56 words
A flash synchronization circuit as recited in claim 1 wherein said circuit means comprises a Schmitt trigger circuit having a first stable state and a second stable state and wherein said circuit means applies said firing signal to said input of said sequence firing circuit when said Schmitt trigger circuit switches to said second stable state.
Claim 5
Dependent Claim
54 words
A flash synchronization circuit as recited in claim 1 wherein said circuit means normally energizes a coil, wherein said means to open said shutter mechanism opens said shutter mechanism in response to the de-energization of said coil, and wherein said firing signal comprises a pulse generated by said coil when said coil is de-energized.
Claim 6
Dependent Claim
97 words
A flash synchronization circuit as recited in claim 1 wherein said sequence firing circuit comprises a plurality of electronic valves each connected in series with a different one of said flashbulbs, said valves being of the type which are rendered conductive in response to a signal applied to a gate electrode thereof and which remain conductive until rendered nonconductive by the current flowing therethrough dropping below a minimum value, and means to render the electronic valve in series with the next flashbulb to be fired conductive in response to said firing signal being applied to said input.
Claim 7
Dependent Claim
55 words
A flash synchronization circuit as recited in claim 5 wherein said shutter mechanism includes means to close said shutter mechanism to terminate said exposure interval a time interval after said shutter mechanism has been opened, and wherein said sequence firing circuit includes means to render said electronic valves nonconducting when said exposure interval is terminated.
Claim 8
Dependent Claim
68 words
A flash synchronization circuit as recited in claim 6 further comprising a coil, means to energize said coil and to de-energize said second coil, said means to close said shutter mechanism to terminate said exposure interval operating in response to the de-energization of said coil, said means to render said electronic valves nonconductive operating in response to the pulse generated by said coil when said coil is de-energized.
Claim 9
Dependent Claim
64 words
A flash synchronization circuit as recited in claim 5 wherein said shutter mechanism includes means to close said shutter mechanism at the end of said exposure interval after said shutter mechanism has been opened by said means to open said shutter mechanism, and wherein there is provided means to prevent said electronic valves From being rendered conductive when said exposure interval is being terminated.
Claim 10
Dependent Claim
17 words
A flash synchronization circuit as recited in claim 5 wherein said electronic valves comprise silicon controlled rectifiers.
Claim 11
Dependent Claim
56 words
A flash synchronization circuit as recited in claim 9 wherein said shutter mechanism includes means to close said shutter mechanism to terminate said exposure interval a time interval after said shutter mechanism has been opened, and wherein said sequence firing circuit includes means to render said silicon controlled rectifiers nonconducting when said exposure interval is terminated.
Claim 12
Dependent Claim
68 words
A flash synchronization circuit as recited in claim 10 further comprising a coil, means to energize said coil and to de-energize said coil, said means to close said shutter mechanism to terminate said exposure interval operating in response to the de-energization of said coil, said means to render said silicon controlled rectifiers nonconductive operating in response to the pulse generated by said coil when said coil is de-energized.
Claim 13
Dependent Claim
63 words
A flash synchronization circuit as recited in claim 9 wherein said shutter mechanism includes means to close said shutter mechanism at the end of said exposure interval after said shutter mechanism has been opened by said means to open said shutter mechanism, and wherein there is provided means to prevent silicon controlled rectifiers from being fired when said exposure interval is being terminated.
Claim 14
Dependent Claim
171 words
A flash synchronization circuit for synchronizing the sequential firing of flashbulbs in an array of said flashbulbs with sequential actuations of a camera shutter mechanism, said camera shutter mechanism including means to open said shutter mechanism to start an exposure interval and to close said shutter mechanism at the end of said exposure interval, comprising a plurality of electronic valves each connected in series with a single different one of said flashbulbs, said electronic valves being of the type which are rendered conductive in response to a gating signal applied to a gate electrode thereof and which remain conductive until rendered nonconductive by the current flowing therethrough dropping below minimum value, means to apply a gating signal to the gate electrode of the one of said electronic valves in series with the next unfired one of said flashbulbs in said sequence at the start of said exposure interval, and means to reduce the current flow through one of said electronic valves below said minimum at the end of said exposure interval.
Claim 15
Dependent Claim
171 words
A flash synchronization circuit for synchronizing the sequential firing of flashbulbs in an array of said flashbulbs with sequential actuations of a camera shutter mechanism, said camera shutter mechanism including means to open said shutter mechanism to start an exposure interval and to close said shutter mechanism at the end of said exposure interval, comprising a plurality of electronic valves each connected in series with a single different one of said flashbulbs, said electronic valves being of the type which are rendered conductive in response to a gating signal applied to a gate electrode thereof and which remain conductive until rendered nonconductive by the current flowing therethrough dropping below minimum value, means to apply a gating signal to the gate electrode of the one of said electronic valves in series with the next unfired one of said flashbulbs in said sequence at the start of said exposure interval, and means to reduce the current flow through one of said electronic valves below said minimum at the end of said exposure interval.
Claim 16
Dependent Claim
73 words
A flash synchronization circuit as recited in claim 13 further comprising a coil, means to energize said coil and to de-energize said coil, said means to close said shutter mechanism to terminate said exposure interval operating in response to the de-energization of said coil, said means to reduce the current flow through said one of said electronic valves operating in response to the pulse generated by said coil when said coil is de-energized.
Claim 17
Dependent Claim
50 words
A flash synchronization circuit as recited in claim 13 wherein said means to reduce the current flow through said one of said electronic valves comprises a circuit shunting the series circuits of said flashbulbs and said electronic valves, said shunting circuit becoming conductive at the end of said exposure interval.
Claim 18
Dependent Claim
17 words
A flash synchronization circuit as recited in claim 13 wherein said electronic valves comprise silicon controlled rectifiers.
Claim 19
Dependent Claim
128 words
A flash synchronization circuit for synchronizing the firing of flash bulbs with sequential actuations of a camera shutter mechanism comprising: a firing circuit for selectively firing at least one said flash bulb from a power supply upon receipt of an electrical firing signal applied to the input thereof, said shutter mechanism including means to open and close said shutter mechanism to define an exposure interval, and electronic circuit means controlling the energization of an electrical coil electromagnetically acting on said shutter mechanism to effect a regulation thereby, said circuit means de-energizing said coil at a predetermined time relative to said exposure interval, causing said coil to generate a pulse as a result of the de-energization thereof, and applying said pulse as said firing signal to said firing circuit.
Claim 20
Dependent Claim
128 words
A flash synchronization circuit for synchronizing the firing of flash bulbs with sequential actuations of a camera shutter mechanism comprising: a firing circuit for selectively firing at least one said flash bulb from a power supply upon receipt of an electrical firing signal applied to the input thereof, said shutter mechanism including means to open and close said shutter mechanism to define an exposure interval, and electronic circuit means controlling the energization of an electrical coil electromagnetically acting on said shutter mechanism to effect a regulation thereby, said circuit means de-energizing said coil at a predetermined time relative to said exposure interval, causing said coil to generate a pulse as a result of the de-energization thereof, and applying said pulse as said firing signal to said firing circuit.
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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) | 1975-10-24 | 1976-04-24 | 1976-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-24 | 1980-04-24 | 1980-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-24 | 1984-04-24 | 1984-10-24 | $7700.00 | Window Closed / Lapsed |