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JPS5560935A - Overhead projector - Google Patents

Overhead projector

Info

Publication number
JPS5560935A
JPS5560935A JP13396078A JP13396078A JPS5560935A JP S5560935 A JPS5560935 A JP S5560935A JP 13396078 A JP13396078 A JP 13396078A JP 13396078 A JP13396078 A JP 13396078A JP S5560935 A JPS5560935 A JP S5560935A
Authority
JP
Japan
Prior art keywords
reflecting mirror
center part
fresnel lens
inclination
angle
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
JP13396078A
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 JP13396078A priority Critical patent/JPS5560935A/en
Publication of JPS5560935A publication Critical patent/JPS5560935A/en
Pending legal-status Critical Current

Links

Landscapes

  • Overhead Projectors And Projection Screens (AREA)

Abstract

PURPOSE: To shorten the height size of the body casing and achieve the reduction in thickness by using an eccentric type as a Fresnel lens and bringing the rays passing the center part of this lens closer to the light source side thereby reducing the angle of inclination of a reflecting mirror.
CONSTITUTION: In the case when the light of a light source lamp 27 is reflected upward by a reflecting mirror 25, the rays b passing a Fresnel lens center part 22a and intersecting orthogonally to an eccentric Fresnel lens 22 go closer to the lamp side by as much as the center part 22a deviates to the lamp 27 side. Hence, it is only required to set the angle of inclination α of the reflecting mirror 25 at about 20W 30° in order to let the rays b intersect orthogonally to the Fresnel lens 22 through the center part 22a, wherein the reflecting mirror 25 assumes a more inclined state than before. Hence, the height size h of the body casing 20 built in with the reflecting mirror 25, etc. becomes smaller by as much as the angle of inclination α of the reflecting mirror 25 becomes smaller, thus the body casing 20 may be made thiner.
COPYRIGHT: (C)1980,JPO&Japio
JP13396078A 1978-10-31 1978-10-31 Overhead projector Pending JPS5560935A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP13396078A JPS5560935A (en) 1978-10-31 1978-10-31 Overhead projector

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP13396078A JPS5560935A (en) 1978-10-31 1978-10-31 Overhead projector

Publications (1)

Publication Number Publication Date
JPS5560935A true JPS5560935A (en) 1980-05-08

Family

ID=15117095

Family Applications (1)

Application Number Title Priority Date Filing Date
JP13396078A Pending JPS5560935A (en) 1978-10-31 1978-10-31 Overhead projector

Country Status (1)

Country Link
JP (1) JPS5560935A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4741613A (en) * 1986-12-19 1988-05-03 Minnesota Mining And Manufacturing Company Reduced height transmissive overhead projector
JPS63167367A (en) * 1986-12-27 1988-07-11 Somar Corp Exposing device for photoengraving

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2507515A1 (en) * 1975-02-21 1976-09-02 Klaus W Reiser & Co Overhead projector for transparent writing support sheets - has internal reflector mirror and fresnel lens system

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2507515A1 (en) * 1975-02-21 1976-09-02 Klaus W Reiser & Co Overhead projector for transparent writing support sheets - has internal reflector mirror and fresnel lens system

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4741613A (en) * 1986-12-19 1988-05-03 Minnesota Mining And Manufacturing Company Reduced height transmissive overhead projector
JPS63167367A (en) * 1986-12-27 1988-07-11 Somar Corp Exposing device for photoengraving

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