WO1988002501A1 - Dispositif optique de projection d'affichages a cristaux liquides - Google Patents

Dispositif optique de projection d'affichages a cristaux liquides Download PDF

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Publication number
WO1988002501A1
WO1988002501A1 PCT/DE1987/000427 DE8700427W WO8802501A1 WO 1988002501 A1 WO1988002501 A1 WO 1988002501A1 DE 8700427 W DE8700427 W DE 8700427W WO 8802501 A1 WO8802501 A1 WO 8802501A1
Authority
WO
WIPO (PCT)
Prior art keywords
liquid crystal
projection
optical device
projection lamp
crystal plate
Prior art date
Application number
PCT/DE1987/000427
Other languages
German (de)
English (en)
Inventor
Ulrich Staiger
Original Assignee
Eastman Kodak Company
Kodak Aktiengesellschaft
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 Eastman Kodak Company, Kodak Aktiengesellschaft filed Critical Eastman Kodak Company
Publication of WO1988002501A1 publication Critical patent/WO1988002501A1/fr

Links

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133526—Lenses, e.g. microlenses or Fresnel lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • 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 an optical device for the projection of liquid crystal displays, in particular for overhead projectors with a liquid crystal plate arranged in the support plane and a Fresnel lens, a projection lamp and a projection lens.
  • liquid crystal display devices for example LCD panels in overhead projectors
  • DE-OS 24 42 621 the use of liquid crystal display devices, for example LCD panels in overhead projectors.
  • the diverging light rays coming from the projection lamp shine through the LCD panel from its center to the edges thereof at a constantly increasing acute angle. Only the center beam passes vertically through the LCD panel. This beam path significantly affects the quality of the images projected by means of the LCD panel, in particular a good contrast cannot be achieved.
  • an overhead projector is designed in such a way that a controllable LCD plate is located in the support plane and a Fresnel lens with a flat, mirrored base area is arranged beneath it.
  • a light beam coming from the projection lamp can have such an unfavorable beam path that it enters the LCD plate at a certain translucent imaging cell at an acute angle and after reflection on the mirror surface of the Fresnel lens as a result of the existing angle of incidence and dropout emerges at a neighboring Abbi Idings cell and thus displays this instead of the desired cell.
  • the result is shadow formation in the projected image or double contours.
  • the invention is based on the task of creating an optical device, in particular for overhead projectors, which displays a -z projecting liquid crystal display with high contrast and in which shadows or double contours do not occur.
  • the projection light rays emanating from the projection lamp run parallel or essentially parallel within the liquid crystal plate.
  • the Fresnel lens is arranged above the liquid crystal plate facing the projection lamp and a plane mirror is arranged below the side of the liquid crystal plate facing away from the projection lamp.
  • an overhead projector is designed for a transmission projection in such a way that a Fresnel lens is arranged above and below the liquid crystal panel.
  • the Fresnel rings of the two Fresnel lenses face the liquid crystal panel.
  • the Fresnel lens and the Ptan mirror and in the transmission projector are arranged in the immediate vicinity of the liquid crystal panel.
  • FIG. 3 shows the arrangement of the optical device according to the invention for an overhead projector according to FIG. 1 in an enlarged partial view
  • Fig. 4 shows a further embodiment in the form of a transmission overhead projector in a schematic representation.
  • an overhead projector 10 is shown schematically, which works on the reflection principle. It consists of a housing 11 in which the optical device according to the invention is accommodated. The latter consists of a controllable liquid crystal plate 12, above which a Fresnel lens 13 and below which a plane mirror 14 are arranged.
  • a projection head 16 is attached to an upright holding arm 15, in which a projection objective 17 and a projection lamp 18 are accommodated.
  • a deflection mirror 19 is also movably arranged on the projection head 16.
  • FIG. 3 shows the arrangement of the liquid crystal panel 12 in an enlarged partial representation.
  • the known arrangement consists of a liquid crystal plate 30 which encloses a liquid crystal layer 32 between two plane-parallel glass plates 31.
  • a Fresnel lens 33 is arranged below the liquid crystal plate 30, the flat bottom 34 of which is provided with a mirror surface 35.
  • a light beam 36 coming from the projection lamp passes through an open cell 37 of the liquid layer 32, continues its path through the Fresnel lens 33, is reflected on the mirror surface 35 in order to penetrate the liquid crystal layer 32 again. Due to the light beam 36 entering at an acute angle through the liquid crystal plate 30, the light beam 39 which is detected on the mirror surface 35 and emerges again through the liquid crystal plate 30 does not penetrate the liquid crystal layer 32 at its entry cell 37 but at an adjacent open cell 37 '. This unfavorable beam path is worsened due to the large distance between the mirror surface 35 and the liquid crystal layer 32. It is also possible for the emerging light beam 39 to strike a blocked liquid crystal cell 38. This leads to shadows or double contours of the image present in the liquid crystal layer 32 and thus z a low-contrast and poor projection.
  • the light beam 23 coming from the projection lamp 18 initially passes through the Fresnel lens 13 and is deflected there in such a way that it plumbs the liquid crystal plate 12 lying beneath it perpendicularly or almost vertically on an open cell 20 liquid crystal layer 21 located between two plane-parallel glass plates 22.
  • the light beam 24 reflected on the plane mirror 14 returns through the same cell 20 of the liquid crystal layer 21 through which it entered.
  • D- * cell 20 is mapped itself in the project on, which leads to images without shadow formation or double contours and with a high contrast.
  • the angle shown in the drawing between the incident light beam 23 and the emerging light beam 24 is only for illustration. In reality it is quite possible that the two rays of light coincide.
  • a high-contrast projection of the image driven in the liquid crystal plate 50 is achieved by means of light rays 51 which are guided in parallel through the liquid crystal plate 50.
  • a Fresnel lens 52 and 53 is arranged both above and below the liquid crystal plate 50, which deflect the light rays 51 coming from the projection lamp 54 in such a way that they pass through the liquid crystal plate 50 in parallel and then the projection ⁇ are fed objectively 56, the projection then takes place via a deflection mirror 57.
  • the Fresnel lenses 52 and 53 with the liquid crystal panel 50 and the projection lamp 54 are arranged in a housing 55.

Landscapes

  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • General Physics & Mathematics (AREA)
  • Mathematical Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Optics & Photonics (AREA)
  • Liquid Crystal (AREA)
  • Overhead Projectors And Projection Screens (AREA)

Abstract

Dans un dispositif optique de projection d'affichages à cristaux liquides, en particulier des rétroprojecteurs ayant une plaque de cristaux liquides (12) sur le plan de projection et une lentille de Fresnel (13), les rayons de lumière (23) d'une lampe de projection se propagent en sens parallèle ou essentiellement parallèle à l'intérieur de la plaque de cristaux liquides (12). Dans un rétroprojecteur fondé sur le principe de réflexion, une lentille de Fresnel (13) est agencée au-dessus du côté de la plaque de cristaux liquides (12) faisant face à la lampe de projection (18) et un miroir plan (14) est agencé au-dessous du côté de la plaque de cristaux liquides (12) à l'opposé de la lampe de projection (18). Grâce à cet agencement, le rayon incident de lumière (23) en provenance de la lampe de projection (18) peut ressortir par la même cellule ouverte (20) de la plaque de cristaux liquides (12), par laquelle il est entré, après avoir été réfléchi par le miroir plan. Ce simple agencement permet d'éviter la formation d'ombres et de contours doubles lors de la projection d'affichages à cristaux liquides.
PCT/DE1987/000427 1986-10-01 1987-09-21 Dispositif optique de projection d'affichages a cristaux liquides WO1988002501A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19863633332 DE3633332A1 (de) 1986-10-01 1986-10-01 Optische einrichtung zur projektion von fluessigkristallanzeigen
DEP3633332.8 1986-10-01

Publications (1)

Publication Number Publication Date
WO1988002501A1 true WO1988002501A1 (fr) 1988-04-07

Family

ID=6310759

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE1987/000427 WO1988002501A1 (fr) 1986-10-01 1987-09-21 Dispositif optique de projection d'affichages a cristaux liquides

Country Status (2)

Country Link
DE (1) DE3633332A1 (fr)
WO (1) WO1988002501A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4986651A (en) * 1989-08-04 1991-01-22 Minnesota Mining And Manufacturing Company Overhead projector with centerless Fresnel lens reflective stage
WO1994016358A1 (fr) * 1992-12-31 1994-07-21 Minnesota Mining And Manufacturing Company Systeme de retroprojection a ecran a cristaux liquides reflechissant

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR0140672B1 (ko) * 1994-09-15 1998-06-15 이헌조 편향장치를 구비한 액정 프로젝터
US7198373B2 (en) * 2005-05-03 2007-04-03 Eastman Kodak Company Display apparatus using LCD panel

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2442621A1 (de) * 1974-09-05 1976-03-18 Minnesota Mining & Mfg Projektor
DE3506968A1 (de) * 1984-04-13 1985-10-17 Demolux Gmbh & Co Kg, 6070 Langen Overhead-projektor
WO1985005192A1 (fr) * 1984-05-08 1985-11-21 Manchester R & D Partnership Projecteur a cristaux liquides, et procede

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2442621A1 (de) * 1974-09-05 1976-03-18 Minnesota Mining & Mfg Projektor
DE3506968A1 (de) * 1984-04-13 1985-10-17 Demolux Gmbh & Co Kg, 6070 Langen Overhead-projektor
WO1985005192A1 (fr) * 1984-05-08 1985-11-21 Manchester R & D Partnership Projecteur a cristaux liquides, et procede

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN, Band 8, Nr. 113 (P-276)(1550), 26. Mai 1984, &JP, A, 5919924 (Aporon Ongaku Kogyo K.K.) 1. Februar 1984 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4986651A (en) * 1989-08-04 1991-01-22 Minnesota Mining And Manufacturing Company Overhead projector with centerless Fresnel lens reflective stage
WO1994016358A1 (fr) * 1992-12-31 1994-07-21 Minnesota Mining And Manufacturing Company Systeme de retroprojection a ecran a cristaux liquides reflechissant
US5333072A (en) * 1992-12-31 1994-07-26 Minnesota Mining And Manufacturing Company Reflective liquid crystal display overhead projection system using a reflective linear polarizer and a fresnel lens

Also Published As

Publication number Publication date
DE3633332A1 (de) 1988-04-14

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