US4238143A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Autofocus movie camera having pulsed terminal drive means
Assignee: Polaroid Corp
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Filing: 1979-01-02
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Granted: 1980-12-09
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Expires: 1999-01-02
Abstract
Abstract The operational range of an adjustable focus lens is subdivided into a plurality of focus zones, of finite size, by a lens control system that produces a plurality of discrete signals representative of said focus zones, said control system utilizing bidirectional drive means to position the movable element of said lens to one of said focus zones from any position within said operational range in order to focus an image of a remote object at an image plane. The present invention optimally increases the focusing speed and the focusing repeatability of said control system while equalizing and minimizing the focusing error introduced into said control system resulting from the use of such focus zones with bidirectional drive means, by anticipating the arrival of said movable lens element at the desired focus zone, disabling the lens drive means for a limited period of time prior to the time that said lens element arrives at said desired focus zone, and then having said drive means provide a pulsating driving force to said movable lens element until said movable lens element reaches said desired focus zone.
Inventors
- 👤 Edwin K. Shenk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 09:12
CPC Classifications
G; G02; G02B; G02B7/00; G02B7/28; G02B7/40
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
181 words
In an autofocusing camera having a displaceable lens, means for determining subject distance, control means energizeable for displacing said lens to a location selected in accordance with said distance determining means to thereby focus an image of the subject on the camera focal plane, said control means including encoder means responsive to lens displacement for producing a plurality of discrete signals, each representative of displacement of said lens to within a respective positional zone of said lens; and said control means including means for terminating displacement of said lens within a positional zone selected in accordance with said distance determining means, the improvement comprising: that said displacement terminating means includes, means for generating a signal representative of said lens at the adjacent positional zone immediately before said selected positional zone; and means for regulating said control means such that it provides a constant force to said displaceable lens before it is positioned to a positional zone immediately adjacent said selected positional zone and provides a pulsating force to said displaceable lens while said lens is positioned within said adjacent positional zone.
Claim 2
Dependent Claim
181 words
In an autofocusing camera having a displaceable lens, means for determining subject distance, control means energizeable for displacing said lens to a location selected in accordance with said distance determining means to thereby focus an image of the subject on the camera focal plane, said control means including encoder means responsive to lens displacement for producing a plurality of discrete signals, each representative of displacement of said lens to within a respective positional zone of said lens; and said control means including means for terminating displacement of said lens within a positional zone selected in accordance with said distance determining means, the improvement comprising: that said displacement terminating means includes, means for generating a signal representative of said lens at the adjacent positional zone immediately before said selected positional zone; and means for regulating said control means such that it provides a constant force to said displaceable lens before it is positioned to a positional zone immediately adjacent said selected positional zone and provides a pulsating force to said displaceable lens while said lens is positioned within said adjacent positional zone.
Claim 3
Dependent Claim
31 words
The apparatus of claim 1, wherein said pulsating force regulating means includes a resistor and capacitor pulse forming network and the output of said network is fed back into its input.
Claim 4
Dependent Claim
23 words
The apparatus of claim 1, wherein all of the pulses produced by said pulsating force drive means are of uniform amplitude and width.
Claim 5
Dependent Claim
23 words
The apparatus of claim 1, wherein the length of time of a force pulse and the time between adjacent force pulses are equal.
Claim 6
Dependent Claim
26 words
The apparatus of claim 1, wherein said adjacent zone signal generating means includes means for determining the adjacent positional zone immediately before said selected positional zone.
Claim 7
Dependent Claim
209 words
In a photographic camera of the type having, means for selectively coupling said camera to a source of energy, an image plane, an adjustable focus lens mounted for displacement over a given operational range where it serves to focus images of subjects positioned within a range of subject distances at said image plane, means for producing a signal indicative of the position of a particular subject within said range of subject distances, means for producing a plurality of discrete focus zone signals that correspond to a plurality of focus zones, said focus zones representing the entire focusing range of said adjustable focus lens, drive means for effecting movement of said lens from either of two directions to a desired focus zone to focus an image of a particular subject at said image plane, the improvement comprising: means for generating a signal representative of said lens at the adjacent focus zone immediately before said particular focus zone; and means for regulating said drive means such that it provides a constant force to said adjustable focus lens before it is positioned to a positional zone immediately adjacent said selected positional zone and provides a pulsating force to said adjustable focus lens while said lens is positioned within said adjacent positional zone.
Claim 8
Dependent Claim
209 words
In a photographic camera of the type having, means for selectively coupling said camera to a source of energy, an image plane, an adjustable focus lens mounted for displacement over a given operational range where it serves to focus images of subjects positioned within a range of subject distances at said image plane, means for producing a signal indicative of the position of a particular subject within said range of subject distances, means for producing a plurality of discrete focus zone signals that correspond to a plurality of focus zones, said focus zones representing the entire focusing range of said adjustable focus lens, drive means for effecting movement of said lens from either of two directions to a desired focus zone to focus an image of a particular subject at said image plane, the improvement comprising: means for generating a signal representative of said lens at the adjacent focus zone immediately before said particular focus zone; and means for regulating said drive means such that it provides a constant force to said adjustable focus lens before it is positioned to a positional zone immediately adjacent said selected positional zone and provides a pulsating force to said adjustable focus lens while said lens is positioned within said adjacent positional zone.
Claim 9
Dependent Claim
31 words
The apparatus of claim 6, wherein said pulsating force regulating means includes a resistor and capacitor pulse forming network and the output of said network is fed back into its input.
Claim 10
Dependent Claim
23 words
The apparatus of claim 6, wherein all of the pulses produced by said pulsating force drive means are of uniform amplitude and width.
Claim 11
Dependent Claim
23 words
The apparatus of claim 6, wherein the length of time of a force pulse and the time between adjacent force pulses are equal.
Claim 12
Dependent Claim
26 words
The apparatus of claim 6, wherein said adjacent zone signal generating means includes means for determining the adjacent positional zone immediately before said selected positional zone.
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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) | 1983-12-09 | 1984-06-09 | 1984-12-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-12-09 | 1988-06-09 | 1988-12-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-12-09 | 1992-06-09 | 1992-12-09 | $7700.00 | Window Closed / Lapsed |