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EP0733229A1 - Ecran de projection - Google Patents

Ecran de projection

Info

Publication number
EP0733229A1
EP0733229A1 EP94911353A EP94911353A EP0733229A1 EP 0733229 A1 EP0733229 A1 EP 0733229A1 EP 94911353 A EP94911353 A EP 94911353A EP 94911353 A EP94911353 A EP 94911353A EP 0733229 A1 EP0733229 A1 EP 0733229A1
Authority
EP
European Patent Office
Prior art keywords
screen
wavelengths
light
projection
filter
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.)
Withdrawn
Application number
EP94911353A
Other languages
German (de)
English (en)
Inventor
Stig Berglund
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.)
OPTICA NOVA ONAB AB
Original Assignee
OPTICA NOVA ONAB AB
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 OPTICA NOVA ONAB AB filed Critical OPTICA NOVA ONAB AB
Publication of EP0733229A1 publication Critical patent/EP0733229A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • 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]
    • H04N9/3102—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM] using two-dimensional electronic spatial light modulators
    • H04N9/3105—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM] using two-dimensional electronic spatial light modulators for displaying all colours simultaneously, e.g. by using two or more electronic spatial light modulators
    • H04N9/3108—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM] using two-dimensional electronic spatial light modulators for displaying all colours simultaneously, e.g. by using two or more electronic spatial light modulators by using a single electronic spatial light modulator
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B30/00—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images
    • G02B30/20—Optical systems or apparatus for producing three-dimensional [3D] effects, e.g. stereoscopic images by providing first and second parallax images to an observer's left and right eyes
    • G02B30/34—Stereoscopes providing a stereoscopic pair of separated images corresponding to parallactically displaced views of the same object, e.g. 3D slide viewers
    • G02B30/35—Stereoscopes providing a stereoscopic pair of separated images corresponding to parallactically displaced views of the same object, e.g. 3D slide viewers using reflective optical elements in the optical path between the images and the observer
    • 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
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/132—Overhead projectors, i.e. capable of projecting hand-writing or drawing during action

Definitions

  • the invention relates to a projection screen which is intended to effectively enhance image or picture contrast, partly in the case of projectors in which the screen is illuminated with broadband white light and partly in the case of projectors in which the screen is illuminated with light in a plurality of narrow bands.
  • the object of different aspects of the invention is to essentially reduce the aforesaid problems.
  • the tilt angle distribution is calculated with regard to incident light and desired angular ranges of reflected light, and the number of mirror elements is chosen with regard to diffraction, so as to obtain a uniform light distribution.
  • One possible manufacture could be obtained, for instance, with the aid of embossing forms manufactured with the aid of electron beam lithography or a "laser-scanner", for instance.
  • the screen can be coated with a filter (for instance, a thin film filter) which has high reflectance for the wavelengths when the light which passes the image transmission elements has high intensity, and high absorption for the wavelengths when said light has a low intensity.
  • a filter for instance, a thin film filter
  • the screen is constructed as a diffusor having a flat transparent coating on which the thin film coating is applied.
  • the diffusor may advantageously be provided with micromirrors according to the aforedescribed principle.
  • the aforedescribed method using a filter coating can be applied with front projection and with rear projection on a transparent screen.
  • Fig. 1 illustrates schematically a projection arrangement that is displaced in the height direction and laterally in relation to the centre of a vertical display screen.
  • Fig. 2 illustrates schematically the construction of a reflecting screen provided with micromirrors.
  • Fig. 3 is a diagram which illustrates how the diffuse reflectance is formed with the aid of a thin film technique when using narrow band light sources.
  • Fig. 4 is a cross-sectional view of a piece of the projection screen.
  • Fig. 1 illustrates schematically a projection arrangement 10 which is displaced in the height direction and in a lateral direction relative to the centre of a vertical display screen 11.
  • Fig. 2 illustrates schematically the principle of constructing the projection screen with micromirrors.
  • the mirrors 45 cover a pixel on the screen and reflect light so that all viewers can see this pixel.
  • Light reflected by mirror 45a has a different direction to the light reflected by mirror 45b.
  • the number of mirrors and the angular distribution can be calculated with regard to diffraction, so as to obtain a uniform light distribution over the eyes of all presumptive viewers.
  • Fig. 3 illustrates how the diffuse-reflection factor for the screen 11 should be formed optimally with the aid of a thin film technique.
  • the axis r is graduated in diffuse-reflection factors, whereas the axis 1 is graduated in wavelengths, with the wavelengths in the illuminating wavelengths R, G, B being marked.
  • the curve 8 shows the diffuse-reflection factor that is obtained, for instance, by coating a diffuse-reflective surface with a thin-film filter which absorbs the light between the colours B and G and between G and R respectively. The curve 8 can therefore also be perceived to show the transmission factor of the thin-film filter, the axis r being graduated in transmission factors.
  • the transmission curve 8 can be configured generally so that essentially only the projected light wavelengths will be reflected while light having wavelengths outside these wavelengths will be absorbed essentially by the screen.
  • the ratio between the transmission factor at the illumination wavelengths R, G, B and the transmission factor of a wavelength between the illumination wavelengths R, G, B should be greater than 1.4, wherein the observed intensity difference corresponds to a factor 2.
  • Fig. 4 is a cross-sectional view of a piece of the projection screen 11, in which the filter layer is referenced 1, the diffusor layer, which may be comprised of micromirrors, is referenced 3, the transparent layer between diffusor layer and the filter is referenced 2, and the supporting base layer is referenced 4. Naturally, the filter 1 may alternatively be applied directly to the diffusor layer 3, without including the intermediate transparent layer 2.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Transforming Electric Information Into Light Information (AREA)
  • Projection Apparatus (AREA)
  • Overhead Projectors And Projection Screens (AREA)
  • Diffracting Gratings Or Hologram Optical Elements (AREA)

Abstract

Ecran (11) de projection comportant une surface réfléchissante diffuse, se présentant par exemple sous forme de micromiroirs (45) dont l'inclinaison ou la pente est aléatoirement distribuée suivant une plage angulaire qui varie sur l'écran (1), et une surface filtrante superposée dont la transmission (8) est telle que seules les longueurs d'ondes pésentes dans la lumière projetée sont réfléchies.
EP94911353A 1993-03-23 1994-03-22 Ecran de projection Withdrawn EP0733229A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
SE9300958A SE9300958L (sv) 1993-03-23 1993-03-23 Offset projektor
SE9300958 1993-03-23
PCT/SE1994/000253 WO1994022049A1 (fr) 1993-03-23 1994-03-22 Ecran de projection

Publications (1)

Publication Number Publication Date
EP0733229A1 true EP0733229A1 (fr) 1996-09-25

Family

ID=20389328

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94911353A Withdrawn EP0733229A1 (fr) 1993-03-23 1994-03-22 Ecran de projection

Country Status (4)

Country Link
EP (1) EP0733229A1 (fr)
AU (2) AU6389694A (fr)
SE (1) SE9300958L (fr)
WO (2) WO1994022048A1 (fr)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996021996A2 (fr) * 1995-01-14 1996-07-18 Optica Nova Onab Ab Separation de la lumiere en pixels couleur dans un dispositif de projection
US5701005A (en) * 1995-06-19 1997-12-23 Eastman Kodak Company Color separating diffractive optical array and image sensor
JP2006527392A (ja) 2003-04-16 2006-11-30 アップストリーム エンジニアリング オーワイ ２ｄ／３ｄデータプロジェクタ
FI20030583L (fi) 2003-04-16 2004-10-17 Upstream Engineering Oy Dataprojektori
KR20070073543A (ko) * 2006-01-05 2007-07-10 최해용 고선명 박막 반사 스크린
WO2007115664A1 (fr) * 2006-04-06 2007-10-18 Oc Oerlikon Balzers Ag Système de projection et d'éclairage dans lequel sont utilisées des lentilles avec eléments optiques diffractifs
EP2052287A1 (fr) 2006-08-10 2009-04-29 Upstream Engineering Oy Procédé et dispositif pour illuminateur

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2004262C3 (de) * 1970-01-30 1975-01-09 Philips Patentverwaltung Gmbh, 2000 Hamburg Projektionsschirm für granulationsfreie Laserstrahlprojektion
US3893748A (en) * 1973-11-30 1975-07-08 Eastman Kodak Co Low scintillation, multi-component projection screen
JPS5492234A (en) * 1977-12-28 1979-07-21 Canon Inc Reflection type screen
DD139904A1 (de) * 1978-12-08 1980-01-23 Joerg Neumann Projektionsschirm bestehend aus feldlinse und streuscheibe
US4268118A (en) * 1979-09-05 1981-05-19 Minnesota Mining And Manufacturing Company Sheeting useful as a projection screen
US4436393A (en) * 1983-01-03 1984-03-13 Minnesota Mining And Manufacturing Company Distortion correction for an overhead projector system
EP0267957A1 (fr) * 1986-05-30 1988-05-25 LAINE, Curtis S. Ecran de projection
CA1327468C (fr) * 1988-09-12 1994-03-08 Dennis F. Vanderwerf Reflecteur de fresnel pour afficheur a cristaux liquides
US5296882A (en) * 1992-12-21 1994-03-22 Minnesota Mining And Manufacturing Company Overhead projector with catadioptric fresnel lens

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9422049A1 *

Also Published As

Publication number Publication date
WO1994022048A1 (fr) 1994-09-29
SE9300958L (sv) 1994-09-24
WO1994022049A1 (fr) 1994-09-29
AU6389694A (en) 1994-10-11
SE9300958D0 (sv) 1993-03-23
AU6389794A (en) 1994-10-11

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Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19951229

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE FR GB

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19981001