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JPS55111931A - Bilevel phase grating type focal plate - Google Patents

Bilevel phase grating type focal plate

Info

Publication number
JPS55111931A
JPS55111931A JP1952279A JP1952279A JPS55111931A JP S55111931 A JPS55111931 A JP S55111931A JP 1952279 A JP1952279 A JP 1952279A JP 1952279 A JP1952279 A JP 1952279A JP S55111931 A JPS55111931 A JP S55111931A
Authority
JP
Japan
Prior art keywords
finder
unit patterns
plate
troughs
acrylic resin
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
JP1952279A
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 JP1952279A priority Critical patent/JPS55111931A/en
Priority to DE19792946005 priority patent/DE2946005A1/en
Publication of JPS55111931A publication Critical patent/JPS55111931A/en
Pending legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B13/00—Viewfinders; Focusing aids for cameras; Means for focusing for cameras; Autofocus systems for cameras
    • G03B13/18—Focusing aids
    • G03B13/24—Focusing screens
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/18—Diffraction gratings
    • G02B5/1866—Transmission gratings characterised by their structure, e.g. step profile, contours of substrate or grooves, pitch variations, materials
    • G02B5/1871—Transmissive phase gratings

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Viewfinders (AREA)
  • Diffracting Gratings Or Hologram Optical Elements (AREA)

Abstract

PURPOSE:To make the finder visual field brighter while maintaining unit patterns small by forming the micro-unit patterns disposed concentrically with the crests and troughs consisting of circles and ring bands regularly to the specified shape on a substrate in the finder. CONSTITUTION:The finder optical system consists of an objective lens 1, condenser lens 2, focal plate 3, and eyepiece lens 4. The focal plate 3 consists of an acrylic resin plate being transparent over the entire part and is disposed regularly in square shape with the fine unit patterns 5 consisting of double crests and troughs on one side. Each unit pattern 5 consists of a circular trough 5a of the center at the same height as that of the surface of the acrylic resin plate and a ring-band form crest 5b encircling concentrically around the same. The height of the crest 5b is set at 0.56mu so that the phase difference phi of the light transmitted therethrough and the light transmitted through the trough 5a becomes pi with respect to the light of a wavelength lambda=0.55mu.
JP1952279A 1978-11-21 1979-02-21 Bilevel phase grating type focal plate Pending JPS55111931A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP1952279A JPS55111931A (en) 1979-02-21 1979-02-21 Bilevel phase grating type focal 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
JP1952279A JPS55111931A (en) 1979-02-21 1979-02-21 Bilevel phase grating type focal plate

Publications (1)

Publication Number Publication Date
JPS55111931A true JPS55111931A (en) 1980-08-29

Family

ID=12001667

Family Applications (1)

Application Number Title Priority Date Filing Date
JP1952279A Pending JPS55111931A (en) 1978-11-21 1979-02-21 Bilevel phase grating type focal plate

Country Status (1)

Country Link
JP (1) JPS55111931A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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
US4946252A (en) * 1987-08-05 1990-08-07 Asahi Kogaku Kogyo Kabushiki Kaisha Focusing screen

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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

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