Patent US4141634A successfully refreshed from Google Patents.
US4141634A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Light leakage preventing device for focal plane shutters
Assignee: Nidec Precision Corp
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Filing: 1977-11-28
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Granted: 1979-02-27
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Expires: 1997-11-28
Abstract
Abstract A light leakage preventing device for focal plane shutters made by interposing a shielding member between a view finder optical system and shutter base plates to intercept a light reaching a film surface through an air gap defined by the shutter base plates from within the view finder optical system. Said shielding member is moved from a light intercepting position to a non-light intercepting position by an interlocking lever operated between the operation of a release button of a photographic camera and the beginning of the operation of shutter blades and is moved from the non-light intercepting position to the light intercepting position simultaneously with the introduction of a light into the view finder optical system from an object to be photographed.
Inventors
- 👤 Nobuyoshi Inoue
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 16:06
CPC Classifications
G; G03; G03B; G03B9/00; G03B9/08; G03B9/10; G03B9/18; G03B19/00; G03B19/02; G03B19/12
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
182 words
A light leakage preventing device for focal plane shutters, comprising: a view finder optical system; a shutter device arranged to intersect at right angles with said view finder optical system and including therein a front shutter blade group a part of which can advance into said view finder optical system and a rear shutter blade group; a shielding member arranged between said view finder optical system and said shutter device to prevent a light passing through said view finder optical system from reaching the surface of a film to be arranged just after said shutter device and capable of allowing said front shutter blade group to advance into said view finder optical system; said shutter device including a first shutter base plate and a partition plate to define a first space for housing therein said front shutter blade group; said partition plate and a second shutter base plate defining a second space for housing said rear shutter blade group; and said shielding member closely covers the upper part of said second space, said shielding member being formed integrally with said partition plate.
Claim 2
Dependent Claim
182 words
A light leakage preventing device for focal plane shutters, comprising: a view finder optical system; a shutter device arranged to intersect at right angles with said view finder optical system and including therein a front shutter blade group a part of which can advance into said view finder optical system and a rear shutter blade group; a shielding member arranged between said view finder optical system and said shutter device to prevent a light passing through said view finder optical system from reaching the surface of a film to be arranged just after said shutter device and capable of allowing said front shutter blade group to advance into said view finder optical system; said shutter device including a first shutter base plate and a partition plate to define a first space for housing therein said front shutter blade group; said partition plate and a second shutter base plate defining a second space for housing said rear shutter blade group; and said shielding member closely covers the upper part of said second space, said shielding member being formed integrally with said partition plate.
Claim 3
Dependent Claim
213 words
A light leakage preventing device for focal plane shutters, comprising: a view finder optical system; a shutter device arranged to intersect at right angles with said view finder optical system and including therein a front shutter blade group a part of which can advance into said view finder optical system and a rear shutter blade group; a shielding member arranged between said view finder optical system and said shutter device to prevent a light passing through said view finder optical system from reaching the surface of a film to be arranged just after said shutter device and capable of allowing said front shutter blade group to advance into said view finder optical system; said shutter device including a pair of shutter base plates to define a space for housing therein said front shutter blade group and rear shutter blade group, and said shielding member being movable between a first position for closing the upper part of said space and a second position for opening the upper part of said space and being moved to said first position before said front shutter blade group and rear shutter blade group begin to operate and to said second position after the completion of the operations of said front shutter blade group and rear shutter blade group.
Claim 4
Dependent Claim
213 words
A light leakage preventing device for focal plane shutters, comprising: a view finder optical system; a shutter device arranged to intersect at right angles with said view finder optical system and including therein a front shutter blade group a part of which can advance into said view finder optical system and a rear shutter blade group; a shielding member arranged between said view finder optical system and said shutter device to prevent a light passing through said view finder optical system from reaching the surface of a film to be arranged just after said shutter device and capable of allowing said front shutter blade group to advance into said view finder optical system; said shutter device including a pair of shutter base plates to define a space for housing therein said front shutter blade group and rear shutter blade group, and said shielding member being movable between a first position for closing the upper part of said space and a second position for opening the upper part of said space and being moved to said first position before said front shutter blade group and rear shutter blade group begin to operate and to said second position after the completion of the operations of said front shutter blade group and rear shutter blade group.
Claim 5
Dependent Claim
247 words
A light leakage preventing device for focal plane shutters, comprising: a view finder optical system; a shutter device arranged to intersect at right angles with said view finder optical system and including therein a front shutter blade group a part of which can advance into said view finder optical system and a rear shutter blade group; a shielding member arranged between said view finder optical system and said shutter device to prevent a light passing through said view finder optical system from reaching the surface of a film to be arranged just after said shutter device and capable of allowing said front shutter blade group to advance into said view finder optical system; said shutter device including a pair of shutter base plates to define a space for housing therein said front shutter blade group and rear shutter blade group, and said shielding member being movable between a first position for closing the upper part of said space and a second position for opening the upper part of said space and being associated with a reflecting mirror which can lead a light from an object to be photographed alternatively to said finder optical system and said film so as to be held in said first position when said reflecting mirror is in the position for leading said light into said view finder optical system and to be held in said second position when said reflecting mirror is in the position for directing said light toward said film.
Claim 6
Dependent Claim
247 words
A light leakage preventing device for focal plane shutters, comprising: a view finder optical system; a shutter device arranged to intersect at right angles with said view finder optical system and including therein a front shutter blade group a part of which can advance into said view finder optical system and a rear shutter blade group; a shielding member arranged between said view finder optical system and said shutter device to prevent a light passing through said view finder optical system from reaching the surface of a film to be arranged just after said shutter device and capable of allowing said front shutter blade group to advance into said view finder optical system; said shutter device including a pair of shutter base plates to define a space for housing therein said front shutter blade group and rear shutter blade group, and said shielding member being movable between a first position for closing the upper part of said space and a second position for opening the upper part of said space and being associated with a reflecting mirror which can lead a light from an object to be photographed alternatively to said finder optical system and said film so as to be held in said first position when said reflecting mirror is in the position for leading said light into said view finder optical system and to be held in said second position when said reflecting mirror is in the position for directing said light toward said film.
Claim 7
Dependent Claim
210 words
A light leakage preventing device for focal plane shutters, comprising: a view finder optical system; a shutter device arranged to intersect at right angles with said view finder optical system and including therein a front shutter blade group a part of which can advance into said view finder optical system and a rear shutter blade group; a shielding member arranged between said view finder optical system and said shutter device to prevent a light passing through said view finder optical system from reaching the surface of a film to be arranged just after said shutter device and capable of allowing said front shutter blade group to advance into said view finder optical system; said shutter device including a pair of shutter base plates to define a space for housing therein said front shutter blade group and rear shutter blade group, and said shielding member being movable between a first position for closing the upper part of said space and a second position for opening the upper part of said space and being associated with a release button to be used to start the operations of said front shutter blade group and rear shutter blade group so as to be moved to said second position when said release button is pushed.
Claim 8
Dependent Claim
210 words
A light leakage preventing device for focal plane shutters, comprising: a view finder optical system; a shutter device arranged to intersect at right angles with said view finder optical system and including therein a front shutter blade group a part of which can advance into said view finder optical system and a rear shutter blade group; a shielding member arranged between said view finder optical system and said shutter device to prevent a light passing through said view finder optical system from reaching the surface of a film to be arranged just after said shutter device and capable of allowing said front shutter blade group to advance into said view finder optical system; said shutter device including a pair of shutter base plates to define a space for housing therein said front shutter blade group and rear shutter blade group, and said shielding member being movable between a first position for closing the upper part of said space and a second position for opening the upper part of said space and being associated with a release button to be used to start the operations of said front shutter blade group and rear shutter blade group so as to be moved to said second position when said release button is pushed.
References Cited (Backward Citations)
US3094913A
Cited
US3411422A
Cited
DE1285862B
Cited
DE1277664B
Cited
US3821768A
Cited
US3999196A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-02-26 | 1982-08-28 | 1983-02-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-02-26 | 1986-08-28 | 1987-02-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-02-26 | 1990-08-28 | 1991-02-27 | $7700.00 | Window Closed / Lapsed |