US4857997A
Expired / Lapsed
US
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Color television camera incorporating a color resolving prism system
Assignee: Canon Inc
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Filing: 1988-04-19
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Granted: 1989-08-15
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Expires: 2008-04-19
Abstract
Abstract In a television camera having a color resolving prism system for forming monochromatic images on the image pickup surfaces of a plurality of image pickup devices by an objective lens the color resolving prism system has first, second, third and fourth prisms as is named in the order from a side of the objective lens along the optic axis of the objective lens, the first and second prisms, with their refracting angles opening in opposite directions, are edisposed with an air layer interposed therebetween or are joined together with a dichroic layer interposed therebetween, the second and third prisms are disposed with an air layer interposed therebetween, the third and fourth prisms are joined together with a second dichroic layer interposed therebetween, and the values of the refracting angles of the first θ 10 or θ 21 ), second θ 10 +θ 11 or θ 22 , third θ 23 and fourth θ 24 prisms satisfy the following conditions: (1) in the case where the first and second prisms are disposed with the air layer interposed therebetween, 5.2°<θ.sub.10 <12° 26.7°<θ.sub.10 +θ.sub.11 <30°, and (2) in the case where the first and second prisms are joined together with the dichroic layer interposed therebetween, 25.8°≦θ.sub.21 ≦30° 18°≦θ.sub.22 ≦20° 28.1°≦θ.sub.23 ≦35.4° 24=-θ.sub.21 +θ.sub.22 +θ.sub.23.
Inventors
- 👤 Kiyoshi Fukami
- 👤 Takeshi Sekiguchi
- 👤 Shigeru Ohshima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:37
CPC Classifications
H; H04; H04N; H04N23/00; H04N23/10; H04N23/13; H04N23/16
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
167 words
A television camera having a color resolving prism system for forming monochromatic images on image pickup surfaces of a plurality of image pickup devices by an objective lens, said color resolving prism system having first, second, third and fourth prisms as is named in the order from a side of the objective lens along the optic axis of said objective lens, said first prism and said second prism being adjacent to each other with an air layer interposed therebetween, said second prism and said third prism being adjacent to each other with an air layer interposed therebetween, a first dichroic layer being formed on a surface of said second prism which faces a surface of said third prism, said third prism and said fourth prism being joined together with a second dichroic layer interposed therebetween, said color resolving prism system satisfying the following conditions: 5.2°<θ.sub.10 <12° 26.7°<θ.sub.10 +θ.sub.11 <30° where θ 10 and θ 10 +θ 11 are refracting angles of said first and second prisms, respectively.
Claim 2
Dependent Claim
167 words
A television camera having a color resolving prism system for forming monochromatic images on image pickup surfaces of a plurality of image pickup devices by an objective lens, said color resolving prism system having first, second, third and fourth prisms as is named in the order from a side of the objective lens along the optic axis of said objective lens, said first prism and said second prism being adjacent to each other with an air layer interposed therebetween, said second prism and said third prism being adjacent to each other with an air layer interposed therebetween, a first dichroic layer being formed on a surface of said second prism which faces a surface of said third prism, said third prism and said fourth prism being joined together with a second dichroic layer interposed therebetween, said color resolving prism system satisfying the following conditions: 5.2°<θ.sub.10 <12° 26.7°<θ.sub.10 +θ.sub.11 <30° where θ 10 and θ 10 +θ 11 are refracting angles of said first and second prisms, respectively.
Claim 3
Dependent Claim
41 words
A television camera according to claim 1, wherein said color resolving prism system furthermore satisfies the following conditions: 19°≦θ.sub.11 ≦22.9° 33.3°≦θ.sub.12 ≦37° θ.sub.13 ≦θ.sub.12 -θ.sub.11 where θ 12 and θ 13 are refracting angles of said third and fourth prisms, respectively.
Claim 4
Dependent Claim
30 words
A television camera according to claim 1, wherein said color resolving prism system furthermore satisfies the following condition: n≧1.7, where n is the refractive index of each of said prisms.
Claim 5
Dependent Claim
21 words
A television camera according to claim 1, wherein said color resolving prism system furthermore satisfies the following condition: 27°≦θ.sub.10 +θ.sub.11 ≦29°.
Claim 6
Dependent Claim
165 words
A television camera having a color resolving prism system for forming monochromatic images on image pickup surfaces of a plurality of image pickup devices by an objective lens, said color resolving prism system comprising a first prism, a second prism, a third prism and a fourth prism as is named in the order from a side of the objective lens, said first and second prisms, with their refracting angles opening in opposite directions, being joined together with a first dichroic layer interposed therebetween, said third and fourth prisms, with their refracting angles opening in opposite directions, being joined together with a second dichroic layer interposed therebetween, said second and third prisms being adjacent to each other with an air layer interposed therebetween, said color resolving prism system satisfying the following conditions: 25.8°<θ.sub.21 ≦30° 13°<θ.sub.22 ≦20° 28.1°≦θ.sub.23 ≦35.4° θ.sub.24 =-θ.sub.21 +θ.sub.22 +θ.sub.23, where θ 21 , θ 22 , θ 23 and θ 24 are refracting angles of said first, second, third and fourth prisms, respectively.
Claim 7
Dependent Claim
165 words
A television camera having a color resolving prism system for forming monochromatic images on image pickup surfaces of a plurality of image pickup devices by an objective lens, said color resolving prism system comprising a first prism, a second prism, a third prism and a fourth prism as is named in the order from a side of the objective lens, said first and second prisms, with their refracting angles opening in opposite directions, being joined together with a first dichroic layer interposed therebetween, said third and fourth prisms, with their refracting angles opening in opposite directions, being joined together with a second dichroic layer interposed therebetween, said second and third prisms being adjacent to each other with an air layer interposed therebetween, said color resolving prism system satisfying the following conditions: 25.8°<θ.sub.21 ≦30° 13°<θ.sub.22 ≦20° 28.1°≦θ.sub.23 ≦35.4° θ.sub.24 =-θ.sub.21 +θ.sub.22 +θ.sub.23, where θ 21 , θ 22 , θ 23 and θ 24 are refracting angles of said first, second, third and fourth prisms, respectively.
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) | 1992-08-14 | 1993-02-13 | 1993-08-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-14 | 1997-02-13 | 1997-08-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-14 | 2001-02-13 | 2001-08-15 | $7700.00 | Window Closed / Lapsed |