JPS5570827A - High level phase grating type focus plate - Google Patents

High level phase grating type focus plate

Info

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
Application number
JP14472378A
Other languages
Japanese (ja)
Inventor
Toshihide Doi
Toyohiko Kashiwagi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Minolta Co Ltd
Original Assignee
Minolta Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Minolta Co Ltd filed Critical Minolta Co Ltd
Priority to JP14472378A priority Critical patent/JPS5570827A/en
Priority to DE19792946005 priority patent/DE2946005A1/en
Publication of JPS5570827A publication Critical patent/JPS5570827A/en
Pending legal-status Critical Current

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
JP14472378A 1978-11-21 1978-11-21 High level phase grating type focus plate Pending JPS5570827A (en)

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)

* Cited by examiner, † Cited by third party
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

Cited By (11)

* Cited by examiner, † Cited by third party
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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