JPH02148009A - Projection lens - Google Patents

Projection lens

Info

Publication number
JPH02148009A
JPH02148009A JP30047288A JP30047288A JPH02148009A JP H02148009 A JPH02148009 A JP H02148009A JP 30047288 A JP30047288 A JP 30047288A JP 30047288 A JP30047288 A JP 30047288A JP H02148009 A JPH02148009 A JP H02148009A
Authority
JP
Grant status
Application
Patent type
Prior art keywords
lens
screen
light
fluorescent
side
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
JP30047288A
Inventor
Kyohei Fukuda
Hiroshi Kataoka
Original Assignee
Hitachi 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

Links

Abstract

PURPOSE: To remarkably improve the luminance without deteriorating a peripheral light quantum ratio by constituting the lens so that a lens group on the side being the nearest to a screen is allowed to have negative power, and a light beam in the direction being near a normal of a fluorescent screen can be taken in.
CONSTITUTION: The lens system is constituted of aspherical concave meniscus lenses 12, 13, a biconvex lens 14 of glass, an aspherical concave lens 15, an aspherical convex lens 16, and a concave lens 17 from a screen side. A fluorescent screen 18 is curved, and on an inner wall of projection tube glass, a multi- layer interference filter formed by laminating high and low refractive index materials is provided. Also, power PF of the lenses 12, 13 positioned on the screen side is set as negative power, and allowed to have a relation of PF < PB against power PB of the lenses 15 - 17 of the fluorescent screen side. Therefore, since a light beam being near a normal of the fluorescent screen 18 can be taken in, and also, the light quantum in the vertical direction is increased by the multi-layer filter, the luminance can be improved remarkably without deteriorating a peripheral light quantum ratio.
COPYRIGHT: (C)1990,JPO&Japio
JP30047288A 1988-11-30 1988-11-30 Projection lens Pending JPH02148009A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP30047288A JPH02148009A (en) 1988-11-30 1988-11-30 Projection lens

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP30047288A JPH02148009A (en) 1988-11-30 1988-11-30 Projection lens

Publications (1)

Publication Number Publication Date
JPH02148009A true true JPH02148009A (en) 1990-06-06

Family

ID=17885206

Family Applications (1)

Application Number Title Priority Date Filing Date
JP30047288A Pending JPH02148009A (en) 1988-11-30 1988-11-30 Projection lens

Country Status (1)

Country Link
JP (1) JPH02148009A (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5666814A (en) * 1979-11-05 1981-06-05 Nitto Kogaku Kk Retrofocus type wide angle lens
JPS61133915A (en) * 1984-12-05 1986-06-21 Matsushita Electric Ind Co Ltd Projection lens
JPS6271915A (en) * 1985-09-25 1987-04-02 Hitachi Ltd Optical system for projection type television
JPS63148221A (en) * 1986-11-24 1988-06-21 Philips Nv Image projection system

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5666814A (en) * 1979-11-05 1981-06-05 Nitto Kogaku Kk Retrofocus type wide angle lens
JPS61133915A (en) * 1984-12-05 1986-06-21 Matsushita Electric Ind Co Ltd Projection lens
JPS6271915A (en) * 1985-09-25 1987-04-02 Hitachi Ltd Optical system for projection type television
JPS63148221A (en) * 1986-11-24 1988-06-21 Philips Nv Image projection system

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