JPS5570827A - High level phase grating type focus plate - Google Patents
High level phase grating type focus plateInfo
- Publication number
- JPS5570827A JPS5570827A JP14472378A JP14472378A JPS5570827A JP S5570827 A JPS5570827 A JP S5570827A JP 14472378 A JP14472378 A JP 14472378A JP 14472378 A JP14472378 A JP 14472378A JP S5570827 A JPS5570827 A JP S5570827A
- Authority
- JP
- Japan
- Prior art keywords
- crests
- troughs
- focus plate
- range
- high level
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Viewfinders (AREA)
- Optical Elements Other Than Lenses (AREA)
Abstract
PURPOSE: To enable focusing to be done for the object in arbitrary directions by disposing the crests of small micro-patterns of the same shape in square or regular triangle form, keeping the area of said crests within a range of 0.16W0.44 of the entire part of the focus plate and letting the phase differences θ of the portions of the crests and troughs satisfy the specific conditions with respect to the wavelengths within a range of 0.45W0.65μ.
CONSTITUTION: A focus plate 3 is made of a transparent acrylic plate (refractive index n=1.49) and is formed with micro-cylindrical crests 3a regularly in square form at its one side. The heights of all the crests are constant and the serrations of the crests and troughs are so set that the phase differences θ of the light transmitted through the crests 3 and the light transmitted through the portions 3b of the troughs satisfy formula [I] with respect to all the wavelengths whithin a range of 0.45W0.65μ. Thereby, the quantity of light of 70% or mroe may be concentrated wihtin the diffusion angle and therefore the bright field of view is obtainable and foucsing may be readily accomplished.
COPYRIGHT: (C)1980,JPO&Japio
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP14472378A JPS5570827A (en) | 1978-11-21 | 1978-11-21 | High level phase grating type focus plate |
DE19792946005 DE2946005A1 (en) | 1978-11-21 | 1979-11-14 | Phase shift raster plate for viewfinder - includes rectangular array with wide angle enhancement |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP14472378A JPS5570827A (en) | 1978-11-21 | 1978-11-21 | High level phase grating type focus plate |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS5570827A true JPS5570827A (en) | 1980-05-28 |
Family
ID=15368810
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP14472378A Pending JPS5570827A (en) | 1978-11-21 | 1978-11-21 | High level phase grating type focus plate |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS5570827A (en) |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5713402A (en) * | 1980-06-27 | 1982-01-23 | Canon Inc | Diffusing plate |
JPS57112329U (en) * | 1980-12-29 | 1982-07-12 | ||
US4421398A (en) * | 1980-06-27 | 1983-12-20 | Canon Kabushiki Kaisha | Focussing plate |
US4697878A (en) * | 1984-03-01 | 1987-10-06 | Minolta Camera Kabushiki Kaisha | Bi-level focusing plate of phase grating type |
JPH01280740A (en) * | 1988-05-07 | 1989-11-10 | Canon Inc | Phase type focusing screen |
JPH01302332A (en) * | 1988-05-31 | 1989-12-06 | Canon Inc | Phase type focusing screen |
US4946252A (en) * | 1987-08-05 | 1990-08-07 | Asahi Kogaku Kogyo Kabushiki Kaisha | Focusing screen |
US5089835A (en) * | 1989-02-28 | 1992-02-18 | Canon Kabushiki Kaisha | Phase-type diffusing plate |
US5124839A (en) * | 1989-11-08 | 1992-06-23 | Canon Kabushiki Kaisha | Phase-type focusing screen |
US5161058A (en) * | 1988-05-31 | 1992-11-03 | Canon Kabushiki Kaisha | Focusing screen |
US5189454A (en) * | 1989-02-28 | 1993-02-23 | Canon Kabushiki Kaisha | Phase-type focusing screen and process for manufacturing the same |
-
1978
- 1978-11-21 JP JP14472378A patent/JPS5570827A/en active Pending
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5713402A (en) * | 1980-06-27 | 1982-01-23 | Canon Inc | Diffusing plate |
US4421398A (en) * | 1980-06-27 | 1983-12-20 | Canon Kabushiki Kaisha | Focussing plate |
JPS57112329U (en) * | 1980-12-29 | 1982-07-12 | ||
US4697878A (en) * | 1984-03-01 | 1987-10-06 | Minolta Camera Kabushiki Kaisha | Bi-level focusing plate of phase grating type |
US4946252A (en) * | 1987-08-05 | 1990-08-07 | Asahi Kogaku Kogyo Kabushiki Kaisha | Focusing screen |
JPH01280740A (en) * | 1988-05-07 | 1989-11-10 | Canon Inc | Phase type focusing screen |
JPH01302332A (en) * | 1988-05-31 | 1989-12-06 | Canon Inc | Phase type focusing screen |
US5161058A (en) * | 1988-05-31 | 1992-11-03 | Canon Kabushiki Kaisha | Focusing screen |
US5089835A (en) * | 1989-02-28 | 1992-02-18 | Canon Kabushiki Kaisha | Phase-type diffusing plate |
US5189454A (en) * | 1989-02-28 | 1993-02-23 | Canon Kabushiki Kaisha | Phase-type focusing screen and process for manufacturing the same |
US5124839A (en) * | 1989-11-08 | 1992-06-23 | Canon Kabushiki Kaisha | Phase-type focusing screen |
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