[go: up one dir, main page]

WO2002014933A1 - Dispositif optique destine a un recepteur de television a projection arriere de profondeur reduite - Google Patents

Dispositif optique destine a un recepteur de television a projection arriere de profondeur reduite Download PDF

Info

Publication number
WO2002014933A1
WO2002014933A1 PCT/US2001/025044 US0125044W WO0214933A1 WO 2002014933 A1 WO2002014933 A1 WO 2002014933A1 US 0125044 W US0125044 W US 0125044W WO 0214933 A1 WO0214933 A1 WO 0214933A1
Authority
WO
WIPO (PCT)
Prior art keywords
mirror
video
projection device
screen
optical axis
Prior art date
Application number
PCT/US2001/025044
Other languages
English (en)
Inventor
Fusao Ishii
Original Assignee
Sony Electronics Inc.
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 Sony Electronics Inc. filed Critical Sony Electronics Inc.
Priority to AU2001283251A priority Critical patent/AU2001283251A1/en
Priority to GB0303214A priority patent/GB2381329A/en
Priority to KR10-2003-7002223A priority patent/KR20030036701A/ko
Priority to EP01962038A priority patent/EP1325382A1/fr
Priority to JP2002520004A priority patent/JP2004519875A/ja
Publication of WO2002014933A1 publication Critical patent/WO2002014933A1/fr
Priority to HK03106687.2A priority patent/HK1054435A1/zh

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/74—Projection arrangements for image reproduction, e.g. using eidophor
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/12—Picture reproducers
    • H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
    • H04N9/3141—Constructional details thereof
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/74—Projection arrangements for image reproduction, e.g. using eidophor
    • H04N5/7408—Direct viewing projectors, e.g. an image displayed on a video CRT or LCD display being projected on a screen

Definitions

  • the present invention relates generally to rear projection televisions, and more particularly to an arrangement of optical elements for reducing the cabinet thickness of a rear projection television.
  • Rear projection type television receivers are very popular due to the large display screens that are available without the need for special installations and/or large viewing areas.
  • three color cathode ray tubes red, green and blue
  • project an image onto a mirror with the image being reflected (and magnified) onto a display screen that may comprise a Fresnel lens arrangement combined with a diffuser.
  • a video projection device includes a cabinet having front and rear sections and a projection tube for projecting a video image.
  • a screen is located in the front section of the cabinet and has a first surface onto which the video image is projected and a second surface for displaying the video image so that it is observable by a viewer.
  • a mirror is arranged in the cabinet for reflecting light to the first surface of the screen.
  • the projection tube is rearwardly facing for projecting the video image onto the mirror.
  • the mirror and the projection tube have optical axes coincident with one another.
  • the optical axis of the mirror and an optical axis of the screen form an angle of 45 degrees with respect to one another.
  • the optical axis of the mirror and an optical axis of the screen may form an angle of less than 45 degrees with respect to one another.
  • At least a portion of the projection tube extends in front of the screen.
  • a diverging lens is provided which is located in an optical path between the projection tube and the mirror.
  • the projection tube is a television projection tube for receiving and projecting a television image.
  • the mirror may be a planar mirror.
  • the mirror may be a spherical mirror or even an aspherical mirror.
  • the spherical or aspherical mirror may be a Fresnel mirror.
  • a video projection device in accordance with another aspect of the invention, includes a cabinet having front and rear sections and a projection tube for projecting a video image.
  • a screen is located in the front section of the cabinet and has a first surface onto which the video image is projected and a second surface for displaying the video image so that it is observable by a viewer.
  • a first mirror is arranged in the cabinet for reflecting light to the first surface of the screen.
  • a second mirror is also arranged in the cabinet for reflecting light to the first mirror.
  • the projection tube is arranged so that it is forward facing for projecting the video image onto the second mirror.
  • FIG. 1 is a schematic diagram of a conventional projection television receiver.
  • FIG. 2 shows a planar mirror with a real object and its corresponding virtual image.
  • FIG. 3 shows a projection television receiver having a first embodiment of the optical arrangement constructed in accordance with the present invention.
  • FIGs. 4-6 show alternative embodiments of the invention.
  • FIG. 7 shows the affect of replacing a planar mirror with a spherical mirror on the location of a virtual image.
  • FIG. 8 shows another alternative embodiment of the invention.
  • FIG. 1 is a schematic diagram of a conventional projection television receiver.
  • a projection cathode ray tube 10 projects an image though a plano-convex optical lens 11 located in front of the tube 10. While FIG. 1 only shows a single cathode ray tube, one of ordinary skill in the art will recognize that three cathode ray tubes are typically employed.
  • a chassis (not shown) that supplies operating voltages and video information to the projection tube 10 by well known means.
  • the focal length of optical lens 11 is selected so that an image produced by the tube 10 appears as an (inverted) image on a screen 12. As shown, the optical axes of the projection tube 10, optical lens 11 and screen 12 are all coincident with one another.
  • FIG. 2 demonstrates well-known operational principals of a planar mirror to facilitate an understanding of the present invention.
  • An object 21 is located a distance x from the front of the planar mirror 20.
  • the mirror 20 forms a virtual image 22 of the object 21.
  • the virtual image 22 is located a distance x behind the mirror 20 and has the same dimensions as object 21.
  • the virtual image may be treated as if were equivalent to the original object. That is, the virtual image can serve as a virtual object for a subsequent mirror or lens.
  • FIG. 3 shows a projection television receiver having a first embodiment of the optical arrangement constructed in accordance with the present invention.
  • a planar mirror 35 is located in the cabinet 36 and has its reflecting surface facing the screen 32.
  • the plane of the mirror 35 is oriented at a 45 angle with respect to the plane of the screen 32.
  • the projection tube 30 is rearwardly facing so that it projects its image onto the planar mirror 35.
  • the optical axis of the projection tube 30 (including its associated optical lens) is parallel to the optical axis of the mirror 35.
  • Projection tube 30 is located so that the mirror 35 forms a virtual image 34 of the picture tube 30 at the location of the picture tube depicted in FIG. 1. Accordingly, based on the analysis presented in FIG.
  • the image formed on the screen 32 by projection tube 30 and mirror 35 is the same as the image formed by a projection tube and lens arrangement that have optical axes coincident with the optical axis of the screen. That is, the screen 32 treats the image 34 of the projection tube received from the mirror 35 as a virtual object.
  • a primary advantage of the present invention is that since the horizontal distance between the screen and the projection tube is less in FIG. 3 than in FIG. 1, the depth of the television cabinet needed for the FIG. 3 arrangement is less than the cabinet depth required in FIG. 1. Of course, as shown, virtual image 34 will be located outside of cabinet 36.
  • FIG. 4 A second embodiment of the invention is shown in FIG. 4. This embodiment is the same as that shown in FIG. 3 except that a plano-convex or diverging lens 43 is now located between the mirror 45 and the screen 42.
  • the diverging lens 43 has the effect of increasing the distance between the screen 42
  • the addition of the diverging lens 43 allows the projection tube to be situated closer to the mirror 45 along their optical axes than would otherwise be the case.
  • the depth of the cabinet in the embodiment of the invention shown in FIG. 3 is determined by the maximum horizontal distance between the mirror 35 and screen 32. This distance can be reduced if the mirror were moved closer to the screen by reducing the angle between them.
  • FIG. 5 shows such an embodiment of the invention in which the plane of the mirror 55 and the plane of the screen 52 form an angle of less than 45°.
  • the projection tube 50 In order to maintain the virtual image 54 of the projection tube 50 along the optical axis of the screen 52, the projection tube 50 needs to be positioned, at least in part, in front of the screen and thus the front portion of the cabinet below the screen needs to be extended.
  • the depth of the top portion 56a of the cabinet 56 containing the screen can be less than in FIG.
  • FIG. 6 shows another embodiment of the invention in which the planar mirror employed in the previous embodiments of the invention is replaced with a spherical mirror 65.
  • FIG. 7 shows the affect of replacing the planar mirror with a spherical mirror on the location of the virtual image of the projection tube and its associated optical lens.
  • Virtual image 73 (shown in dashed lines) represents the location of the picture tube 70 when a flat mirror is employed.
  • Virtual image 73' represents the location of picture tube 70 when the flat mirror is replaced by spherical mirror 75.
  • the spherical mirror increases the distance between the mirror 75 and the virtual image.
  • the distance between the screen 62 and the virtual object 64 of the projection tube 60 is increased.
  • a spherical mirror allows the projection tube 60 to be situated closer to the mirror 35 along their optical axes than would we possible with a flat mirror.
  • mirror 65 shown in FIG. 7 has been described as a spherical mirror, mirror 65 more generally may be an aspherical mirror, which has a curvature, selected to minimize defocusing of the image on the screen.
  • FIG. 8 shows another embodiment of the invention in which a second mirror
  • Second mirror 86 is a planar mirror used to reflect the image from the projection tube 80 to the first mirror 85 so that the projection tube 80 may now be forward facing rather than rearwardly facing.
  • the second mirror 86 and projection tube 80 are arranged so that the second mirror 86 forms a virtual image
  • first mirror 85 shown in FIG. 8 is a planar mirror
  • first mirror 85 alternatively may be a spherical or aspherical mirror such as shown in FIG. 6.
  • the spherical or aspherical mirror shown in FIG. 6 can be replaced with a Fresnel mirror.
  • a Fresnel mirror is a flat mirror that behaves as a concave or convex mirror, thus eliminating the problems associated with relatively large spherical mirrors such as their size, weight and difficulty of manufacturing.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Projection Apparatus (AREA)
  • Transforming Electric Information Into Light Information (AREA)

Abstract

Un dispositif de projection vidéo tel qu'un récepteur de télévision comprend un coffret (36) pourvu de sections avant et arrière, et un tube de projection (30) servant à projeter une image vidéo. Un écran (32) est situé dans la section avant dudit coffret et présente une première surface sur laquelle l'image vidéo est projetée, et une seconde surface d'affichage de l'image vidéo, de telle manière qu'elle peut être observée par un téléspectateur. On dispose un miroir (35) dans le coffret de manière à réfléchir la lumière sur la première surface de l'écran. Le tube de projection fait face au niveau arrière afin de projeter l'image vidéo sur le miroir.
PCT/US2001/025044 2000-08-16 2001-08-09 Dispositif optique destine a un recepteur de television a projection arriere de profondeur reduite WO2002014933A1 (fr)

Priority Applications (6)

Application Number Priority Date Filing Date Title
AU2001283251A AU2001283251A1 (en) 2000-08-16 2001-08-09 Optical arrangement for a rear projection television receiver having reduced depth
GB0303214A GB2381329A (en) 2000-08-16 2001-08-09 Optical arrangement for a rear projection television receiver having reduced depth
KR10-2003-7002223A KR20030036701A (ko) 2000-08-16 2001-08-09 감소된 깊이를 갖는 배면 투사 텔레비전 수상기를 위한광학 배열체
EP01962038A EP1325382A1 (fr) 2000-08-16 2001-08-09 Dispositif optique destine a un recepteur de television a projection arriere de profondeur reduite
JP2002520004A JP2004519875A (ja) 2000-08-16 2001-08-09 背面投射型テレビジョン受信機の薄型化のための光学的配置
HK03106687.2A HK1054435A1 (zh) 2000-08-16 2003-09-18 用於高度減小的後向投射式電視接收機的光學裝置

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US63983900A 2000-08-16 2000-08-16
US09/639,839 2000-08-16

Publications (1)

Publication Number Publication Date
WO2002014933A1 true WO2002014933A1 (fr) 2002-02-21

Family

ID=24565761

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2001/025044 WO2002014933A1 (fr) 2000-08-16 2001-08-09 Dispositif optique destine a un recepteur de television a projection arriere de profondeur reduite

Country Status (7)

Country Link
EP (1) EP1325382A1 (fr)
JP (1) JP2004519875A (fr)
KR (1) KR20030036701A (fr)
AU (1) AU2001283251A1 (fr)
GB (1) GB2381329A (fr)
HK (1) HK1054435A1 (fr)
WO (1) WO2002014933A1 (fr)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4573769A (en) * 1983-07-25 1986-03-04 U.S. Philips Corporation Projection lens system
US4578710A (en) * 1983-05-09 1986-03-25 Pioneer Electronic Corporation Lens system for projection television
US4729631A (en) * 1986-04-30 1988-03-08 Mitsubishi Rayon Co., Ltd. Rear projection screen
US4864390A (en) * 1986-08-22 1989-09-05 North American Philips Corporation Display system with equal path lengths
US4918535A (en) * 1988-10-25 1990-04-17 Robert Bosch Gmbh Television projection system
US5860720A (en) * 1995-10-03 1999-01-19 Sony Corporation Projection apparatus

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4578710A (en) * 1983-05-09 1986-03-25 Pioneer Electronic Corporation Lens system for projection television
US4573769A (en) * 1983-07-25 1986-03-04 U.S. Philips Corporation Projection lens system
US4729631A (en) * 1986-04-30 1988-03-08 Mitsubishi Rayon Co., Ltd. Rear projection screen
US4864390A (en) * 1986-08-22 1989-09-05 North American Philips Corporation Display system with equal path lengths
US4864390B1 (fr) * 1986-08-22 1990-12-11 Philips Corp
US4918535A (en) * 1988-10-25 1990-04-17 Robert Bosch Gmbh Television projection system
US5860720A (en) * 1995-10-03 1999-01-19 Sony Corporation Projection apparatus

Also Published As

Publication number Publication date
KR20030036701A (ko) 2003-05-09
GB0303214D0 (en) 2003-03-19
JP2004519875A (ja) 2004-07-02
GB2381329A (en) 2003-04-30
HK1054435A1 (zh) 2003-11-28
EP1325382A1 (fr) 2003-07-09
AU2001283251A1 (en) 2002-02-25

Similar Documents

Publication Publication Date Title
US6857750B2 (en) Offset projection for slim rear projection displays
KR100881417B1 (ko) 180°보다 큰 각도로 이미지를 투사하기 위한 방법 및시스템
US4717248A (en) Display system
US7604354B1 (en) Three-dimensional projection apparatus using coaxial optical alignment
US6273570B1 (en) Compact light path and package for liquid crystal projection displays
EP0440675B1 (fr) Systeme de projection pour television
JP3371654B2 (ja) 投射型ディスプレイ装置
EP1202079A2 (fr) Systeme de projection
EP1039337A1 (fr) Ecran de rétroprojection
JP2674740B2 (ja) 投 写 レ ン ズ 系
EP1325382A1 (fr) Dispositif optique destine a un recepteur de television a projection arriere de profondeur reduite
GB2402497A (en) Optical arrangement for a rear projection television receiver having reduced depth
EP1646231A1 (fr) Projecteur d'images
US6317262B1 (en) Telescope with auxiliary image generator
KR100364666B1 (ko) 박형 프로젝션 시스템
JPH04362623A (ja) 背面投射形画像表示装置
KR100668190B1 (ko) 보정된 수직 시야각을 가지는 프로젝션 스크린
KR100343964B1 (ko) 후면 투사형 표시 장치의 투사 스크린
KR100698754B1 (ko) 프로젝션 시스템
KR20010005203A (ko) 프로젝션 텔레비전
US5142373A (en) Rear projection television set having improved contrast
JPH0678253A (ja) 投写型テレビジョン装置
KR200273340Y1 (ko) 반사스크린 영상박스의 구조
JP2005189784A (ja) リアプロジェクター
JP2006134653A (ja) 投写形ブラウン管

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT TZ UA UG UZ VN YU ZA ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

ENP Entry into the national phase

Ref country code: GB

Ref document number: 0303214

Kind code of ref document: A

Free format text: PCT FILING DATE = 20010809

Format of ref document f/p: F

121 Ep: the epo has been informed by wipo that ep was designated in this application
DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
WWE Wipo information: entry into national phase

Ref document number: 1020037002223

Country of ref document: KR

WWE Wipo information: entry into national phase

Ref document number: 2002520004

Country of ref document: JP

WWE Wipo information: entry into national phase

Ref document number: 2001962038

Country of ref document: EP

WWP Wipo information: published in national office

Ref document number: 1020037002223

Country of ref document: KR

REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

WWP Wipo information: published in national office

Ref document number: 2001962038

Country of ref document: EP

WWW Wipo information: withdrawn in national office

Ref document number: 2001962038

Country of ref document: EP