JPS559568A - Focal plate using phase type diffraction grating - Google Patents

Focal plate using phase type diffraction grating

Info

Publication number
JPS559568A
JPS559568A JP8258478A JP8258478A JPS559568A JP S559568 A JPS559568 A JP S559568A JP 8258478 A JP8258478 A JP 8258478A JP 8258478 A JP8258478 A JP 8258478A JP S559568 A JPS559568 A JP S559568A
Authority
JP
Japan
Prior art keywords
diffracted light
diffraction grating
focal plate
crests
bright
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
JP8258478A
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 JP8258478A priority Critical patent/JPS559568A/en
Publication of JPS559568A publication Critical patent/JPS559568A/en
Pending legal-status Critical Current

Links

Landscapes

  • Viewfinders (AREA)
  • Diffracting Gratings Or Hologram Optical Elements (AREA)

Abstract

PURPOSE: To obtain the defocus image of a bright visual field, easy focusing and of a natural state to be obtained by leaving zero-order diffracted light within the range where the intensity ratios to total diffracted light become the specific ratios.
CONSTITUTION: Unit patterns having two square shape crests are arrayed in multiplicity in square form on one surface of a focal plate 1. Now, when a signal color spot light source of, e.g., a wavelength λ=550 mm is used and the image of said light source by this focal plate 1 is observed, the bright and natural defocus image may be observed if the values of the area ratio γh that the portions of the crests of the diffraction grating occupy in the entire part of the diffraction grating of the focal plate are taken at 0.66, 0.77 in the boundary region of the phase differences θ=π by the combinations indicated by the shaded part of the graph, e.g., the portions of the crests and troughs of light. The intensity ratios R0 of this time are 12%, 33%. Namely, if the 0 order diffracted light is left within the range where the intensity ratios to the total diffracted light become 5% to 50%, the bright and natural defocus images may be obtained.
COPYRIGHT: (C)1980,JPO&Japio
JP8258478A 1978-07-06 1978-07-06 Focal plate using phase type diffraction grating Pending JPS559568A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP8258478A JPS559568A (en) 1978-07-06 1978-07-06 Focal plate using phase type diffraction grating

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP8258478A JPS559568A (en) 1978-07-06 1978-07-06 Focal plate using phase type diffraction grating

Publications (1)

Publication Number Publication Date
JPS559568A true JPS559568A (en) 1980-01-23

Family

ID=13778521

Family Applications (1)

Application Number Title Priority Date Filing Date
JP8258478A Pending JPS559568A (en) 1978-07-06 1978-07-06 Focal plate using phase type diffraction grating

Country Status (1)

Country Link
JP (1) JPS559568A (en)

Cited By (8)

* 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
US4336989A (en) * 1979-11-29 1982-06-29 Canon Kabushiki Kaisha Focusing screen
US4598977A (en) * 1980-08-26 1986-07-08 Minolta Camera Kabushiki Kaisha Bi-level phase grating focusing plate
US4697878A (en) * 1984-03-01 1987-10-06 Minolta Camera Kabushiki Kaisha Bi-level focusing plate of phase grating type
JPS62238520A (en) * 1986-04-10 1987-10-19 Canon Inc Optical modulator
US5089835A (en) * 1989-02-28 1992-02-18 Canon Kabushiki Kaisha Phase-type diffusing plate
JPH0453606A (en) * 1990-06-15 1992-02-21 Riken Seiki Kk Collet chuck fitter and formation thereof
US5161058A (en) * 1988-05-31 1992-11-03 Canon Kabushiki Kaisha Focusing screen

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5216226A (en) * 1975-07-28 1977-02-07 Canon Inc Focusing device

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5216226A (en) * 1975-07-28 1977-02-07 Canon Inc Focusing device

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4336989A (en) * 1979-11-29 1982-06-29 Canon Kabushiki Kaisha Focusing screen
JPS5713402A (en) * 1980-06-27 1982-01-23 Canon Inc Diffusing plate
US4598977A (en) * 1980-08-26 1986-07-08 Minolta Camera Kabushiki Kaisha Bi-level phase grating focusing plate
US4697878A (en) * 1984-03-01 1987-10-06 Minolta Camera Kabushiki Kaisha Bi-level focusing plate of phase grating type
JPS62238520A (en) * 1986-04-10 1987-10-19 Canon Inc Optical modulator
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
JPH0453606A (en) * 1990-06-15 1992-02-21 Riken Seiki Kk Collet chuck fitter and formation thereof

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