US3839724A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Depth of field indicator for zoom lenses
Assignee: Nippon Kayaku Co Ltd
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Filing: 1973-08-06
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Granted: 1974-10-01
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Expires: 1993-08-06
Abstract
Abstract In a zoom lens system of the type wherein zooming is accomplished by rotation of an operating or zooming ring, the lens casing is constructed so as to indicate a depth of field corresponding to any desired f-value and any desired focal length when an aperture ring is rotated toward smaller f-values and when the zooming ring is rotated toward wider angles. The extent of the debth of field is indicated by two movable indicators respectively mounted on two rotatable rings.
Inventors
- 👤 T Muryoi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:21
CPC Classifications
G; G03; G03B; G03B17/00; G03B17/02; G03B17/12; G03B17/14
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
237 words
A zoom lens system comprising: a zooming ring rotatably mounted on the outer periphery of a lens casing; an aperture ring rotatably mounted on said lens casing; a distance ring for focusing rotatably mounted on said lens casing, said distance ring having a distance scale formed radially on the outer periphery thereof; said lens casing having guide means formed in an outer peripheral portion thereof and extending radially thereof; an inner casing fixedly secured within said lens casing; a first rotatable member having a first indicator portion arranged for cooperation with said guide means and opposed to said distance scale; a second rotatable member having a second indicator portion arranged for cooperation with said guide means and opposed to said distance scale, said second rotatable member being disposed adjacent said first rotatable member; a differential gear for differentially detecting the extent of rotation of said aperture ring and of said zooming ring and transmitting the detected extent of rotation to said first rotatable member; and means for transmitting a rotation equal in extent but opposite in direction to the rotation of said first rotatable member from the same to said second rotatable member, saiD transmission means being connected to said first and second rotatable members so as to increase the spacing between said first and second indicator portions when said aperture ring is rotated toward small f-values and when said zooming ring is rotated toward wider angles.
Claim 2
Dependent Claim
237 words
A zoom lens system comprising: a zooming ring rotatably mounted on the outer periphery of a lens casing; an aperture ring rotatably mounted on said lens casing; a distance ring for focusing rotatably mounted on said lens casing, said distance ring having a distance scale formed radially on the outer periphery thereof; said lens casing having guide means formed in an outer peripheral portion thereof and extending radially thereof; an inner casing fixedly secured within said lens casing; a first rotatable member having a first indicator portion arranged for cooperation with said guide means and opposed to said distance scale; a second rotatable member having a second indicator portion arranged for cooperation with said guide means and opposed to said distance scale, said second rotatable member being disposed adjacent said first rotatable member; a differential gear for differentially detecting the extent of rotation of said aperture ring and of said zooming ring and transmitting the detected extent of rotation to said first rotatable member; and means for transmitting a rotation equal in extent but opposite in direction to the rotation of said first rotatable member from the same to said second rotatable member, saiD transmission means being connected to said first and second rotatable members so as to increase the spacing between said first and second indicator portions when said aperture ring is rotated toward small f-values and when said zooming ring is rotated toward wider angles.
Claim 3
Dependent Claim
65 words
A zoom lens system as defined in claim 1, wherein said guide means is a pair of slots formed in said lens casing and said first and second indicators each project through and cooperate with one of said slots, said first rotatable member being disposed between said lens casing and said inner casing and said second rotatable member being disposed adjacent said first rotatable member.
Claim 4
Dependent Claim
77 words
A zoom lens system as defined in claim 1, wherein said differential gear includes: an internal gear operatively associated with said zooming ring and mounted for rotation on the inner periphery of said lens casing; an external gear operatively associated with said aperture ring and mounted for rotation on the outer periphery of said inner casing; and a planetary gear meshing with both of said internal and external gears and rotatably mounted on said first rotatable member.
Claim 5
Dependent Claim
96 words
A zoom system casing as defined in claim 1, wherein said transmission means includes: a first gear portion provided in an inner peripheral portion of said first rotatable member; a second gear portion provided in an inner peripheral portion of said second rotatable member; a first gear rotatably mounted on said inner casing and meshing with said first gear portion; and a second gear rotatably mounted on said inner casing and meshing with both of said second gear portion and said first gear, said second gear having the same number of teeth as said first gear.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-30 | 1978-04-01 | 1978-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-30 | 1982-04-01 | 1982-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-30 | 1986-04-01 | 1986-10-01 | $7700.00 | Window Closed / Lapsed |