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JPS5557840A - Overhead projector capable of projecting on vertical plane - Google Patents

Overhead projector capable of projecting on vertical plane

Info

Publication number
JPS5557840A
JPS5557840A JP13063478A JP13063478A JPS5557840A JP S5557840 A JPS5557840 A JP S5557840A JP 13063478 A JP13063478 A JP 13063478A JP 13063478 A JP13063478 A JP 13063478A JP S5557840 A JPS5557840 A JP S5557840A
Authority
JP
Japan
Prior art keywords
lens
fresnel lens
center
reflecting mirror
screen
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
JP13063478A
Other languages
Japanese (ja)
Inventor
Toyoo Ishii
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.)
Gakken Holdings Co Ltd
Original Assignee
Gakken 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 Gakken Co Ltd filed Critical Gakken Co Ltd
Priority to JP13063478A priority Critical patent/JPS5557840A/en
Publication of JPS5557840A publication Critical patent/JPS5557840A/en
Pending legal-status Critical Current

Links

Landscapes

  • Overhead Projectors And Projection Screens (AREA)

Abstract

PURPOSE: To obtain a projector capable of always projecting in-focus, normal image without distorsion even if an angle of elevation is given to a vertical screen above, by using eccentric Fresnel lens, and providing a projector lens just above the center of eccentric Fresnel lens in the higher part of the stage and other things.
CONSTITUTION: Multiple prism-like refraction planes 10b are formed concentrically in an eccentric Fresnel lens 10 around the center part 10a thereof, and the center is deviated by a proper extent. Above a transparent stage 11 is placed the Fresnel lens 10 in parallel disposition. The light from a light source 15 passes through a concave mirror 16, a lens 14, and a reflecting mirror 13 and the Fresnel lens 10, and is projected on a screen 19 through projector lens 17 and reflecting mirror 18. Being placed close to the light source 15 side in the center 10a of the Fresnel lens 10, the lens 17 is placed just above it. When the reflecting mirror 18 is placed at the same angle as angle α formed by the light beam c, a normal image is projected on the screen 19. Thus, the image, not distorted in trapezoidal form, is entirely adjusted in focus correctly.
COPYRIGHT: (C)1980,JPO&Japio
JP13063478A 1978-10-24 1978-10-24 Overhead projector capable of projecting on vertical plane Pending JPS5557840A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP13063478A JPS5557840A (en) 1978-10-24 1978-10-24 Overhead projector capable of projecting on vertical plane

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP13063478A JPS5557840A (en) 1978-10-24 1978-10-24 Overhead projector capable of projecting on vertical plane

Publications (1)

Publication Number Publication Date
JPS5557840A true JPS5557840A (en) 1980-04-30

Family

ID=15038930

Family Applications (1)

Application Number Title Priority Date Filing Date
JP13063478A Pending JPS5557840A (en) 1978-10-24 1978-10-24 Overhead projector capable of projecting on vertical plane

Country Status (1)

Country Link
JP (1) JPS5557840A (en)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2517083A1 (en) * 1981-11-26 1983-05-27 Sony Corp RETROPROJECTION APPARATUS
JPS59281A (en) * 1982-04-28 1984-01-05 アールシーエー　ライセンシング　コーポレーシヨン Background projection type television receiver screen
JPS6298336A (en) * 1985-10-24 1987-05-07 Fuji Photo Film Co Ltd Reflection type overhead projector with variable power
JPS63170633A (en) * 1987-01-09 1988-07-14 Hitachi Ltd Projecting device
EP0277469A2 (en) * 1987-01-22 1988-08-10 Optica Nova ONAB AB Projector apparatus
JPS6417531U (en) * 1987-07-21 1989-01-27
US4968134A (en) * 1988-06-29 1990-11-06 Ricoh Company, Ltd. Overhead projector
JPH058555U (en) * 1983-01-03 1993-02-05 ミネソタ マイニング アンド マニユフアクチユアリング コンパニー Overhead Projector
JPH058554U (en) * 1983-01-03 1993-02-05 ミネソタ マイニング アンド マニユフアクチユアリング コンパニー Overhead Projector

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2507510A1 (en) * 1975-02-21 1976-08-26 Rawell Kg Kunststoff Und Kunst Support wall precast reinforced concrete section - has double ribbed steel bar reinforcement rod with U form lower end

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2507510A1 (en) * 1975-02-21 1976-08-26 Rawell Kg Kunststoff Und Kunst Support wall precast reinforced concrete section - has double ribbed steel bar reinforcement rod with U form lower end

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2517083A1 (en) * 1981-11-26 1983-05-27 Sony Corp RETROPROJECTION APPARATUS
JPS5879731U (en) * 1981-11-26 1983-05-30 ソニー株式会社 rear projector device
JPS59281A (en) * 1982-04-28 1984-01-05 アールシーエー　ライセンシング　コーポレーシヨン Background projection type television receiver screen
JPH058555U (en) * 1983-01-03 1993-02-05 ミネソタ マイニング アンド マニユフアクチユアリング コンパニー Overhead Projector
JPH058554U (en) * 1983-01-03 1993-02-05 ミネソタ マイニング アンド マニユフアクチユアリング コンパニー Overhead Projector
JPS6298336A (en) * 1985-10-24 1987-05-07 Fuji Photo Film Co Ltd Reflection type overhead projector with variable power
JPH0535849B2 (en) * 1985-10-24 1993-05-27 Fuji Photo Film Co Ltd
JPS63170633A (en) * 1987-01-09 1988-07-14 Hitachi Ltd Projecting device
EP0277469A2 (en) * 1987-01-22 1988-08-10 Optica Nova ONAB AB Projector apparatus
JPS6417531U (en) * 1987-07-21 1989-01-27
US4968134A (en) * 1988-06-29 1990-11-06 Ricoh Company, Ltd. Overhead projector

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