[go: up one dir, main page]

EP1636638A1 - Compensateur modifie d'angles de biais pour afficheurs a cristaux liquides a retardement residuel - Google Patents

Compensateur modifie d'angles de biais pour afficheurs a cristaux liquides a retardement residuel

Info

Publication number
EP1636638A1
EP1636638A1 EP04736437A EP04736437A EP1636638A1 EP 1636638 A1 EP1636638 A1 EP 1636638A1 EP 04736437 A EP04736437 A EP 04736437A EP 04736437 A EP04736437 A EP 04736437A EP 1636638 A1 EP1636638 A1 EP 1636638A1
Authority
EP
European Patent Office
Prior art keywords
retardance
light
state
recited
polarization
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Withdrawn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
EP04736437A
Other languages
German (de)
English (en)
Inventor
Duncan J. Anderson
Peter Johannes Michiel Janssen
Khalid Shahzad
Jeffrey Arthur Shimizu
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.)
Koninklijke Philips NV
Original Assignee
Koninklijke Philips Electronics NV
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 Koninklijke Philips Electronics NV filed Critical Koninklijke Philips Electronics NV
Publication of EP1636638A1 publication Critical patent/EP1636638A1/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Withdrawn legal-status Critical Current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
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • 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
    • 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
    • G02F1/13363—Birefringent elements, e.g. for optical compensation
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
    • 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
    • G02F1/13363—Birefringent elements, e.g. for optical compensation
    • G02F1/133637—Birefringent elements, e.g. for optical compensation characterised by the wavelength dispersion
    • 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
    • H04N5/7416—Projection arrangements for image reproduction, e.g. using eidophor involving the use of a spatial light modulator, e.g. a light valve, controlled by a video signal
    • H04N5/7441—Projection arrangements for image reproduction, e.g. using eidophor involving the use of a spatial light modulator, e.g. a light valve, controlled by a video signal the modulator being an array of liquid crystal cells

Definitions

  • Liquid crystal (LC) technology has been applied in projection displays for use in projection televisions, computer monitors, point of sale displays, and electronic cinema, to mention a few applications.
  • polarization discriminating device between the LC device (panel) and projection optics used to form the image.
  • these polarization discriminating device are MacNeille-type polarization beamsplitters, which ideally completely reflect light in one polarization state (e.g., S-polarized light) and completely transmits light in an orthogonal polarization state (e.g., P-polarized light).
  • the PBS, or similar device is used to separate 'bright-state' light reflected from the device, which enters the projection lens and is imaged onto a screen, from 'dark-state' light that is ideally reflected back towards the light source.
  • the preferred transmission (P-polarized) and reflected (S-polarized) polarization states of such a PBS are geometrical in nature and are defined by the normal direction of the tilted optical coating surface and the propagation direction of the ray.
  • a projection system illuminates the LC device over a finite range of angles as defined by the pupil of the system, and hence the transmitted p-polarization plane is a function of the pupil location.
  • the LC device should act as a 'mirror' for light in the black state. As such, the net retardance of the LC device should be zero. However, in reality the net retardance of the LC device is not always zero, and the contribution of the device retardance further exacerbates the problem of separating the polarization states reflected from the LCD. Ultimately, this impacts the contrast of the projected image.
  • a light valve device having a first optical retardance is optically coupled to a modified skew angle compensator, which has a second optical retardance.
  • the sum of the first optical retardance and the second optical retardance substantially equals a retardance of a quarter-wave retarder over a prescribed wavelength range.
  • Fig. 1 is a perspective view of a reflective LCD device in a projection system in accordance with an exemplary embodiment.
  • Fig. 2 is a conceptual view of the sequence of retarders representing the device compensator and the strongly anchored liquid crystal at the substrate interfaces of an LC device in accordance with an exemplary embodiment.
  • Figs. 3a and 3b are perspective views showing the residual retardance of an LCOS device that either adds to or subtracts from the retardance of a skew angle compensator in accordance with an exemplary embodiment.
  • Figs. 4a and 4b are theoretical and actual graphical representations, respectively, of the optical retardance (nm) versus wavelength of modified skew angle compensators in accordance with an exemplary embodiment.
  • an exemplary embodiment compensates for the non-zero retardance of an LC device while operating in the "black" state by providing a skew angle compensator of a chosen retardance such that the net retardance of the skew angle compensator/LC device combination is substantially that of a quarter wave retarder.
  • Fig. 1 shows a reflective LCD device 100 in accordance with an exemplary embodiment.
  • An input beam 101 from an optical source 109 is predominantly P- polarized, and is incident on a PBS 1 10, which is illustratively a MacNielle-type beamsplitter. In the ideal case, all light from the input beam 101 would be incident on the PBS 110.
  • the PBS 1 10 transmits light 103 of a first polarization state (e.g., P polarized light), and reflects light 102 of a second polarization state (e.g., S polarized light), which is orthogonal to the first polarization state.
  • a first polarization state e.g., P polarized light
  • S polarized light e.g., S polarized light
  • the light 103 comprises primarily P-polarized light. This light traverses a skew angle compensating retarder 104, and a reflective LC device 105, which is illustratively an LCOS device.
  • the light 103 is transmitted by the skew angle compensator 104, is reflected by the LCOS device 105 and further is transmitted again by the skew angle compensator 104.
  • the light 112 exiting the skew angle compensator 104 has had its polarization state transformed relative to the input polarization state of the light 103.
  • the sum of the retardance of the skew angle retarder 104 and the LC device 105 is substantially equal to that of a half- wave retarder over a chosen wavelength range. It is noted that the slow axis of this effective "summed" retarder is aligned to the nominal P-poIarization direction of the PBS.
  • the effective half-wave retarder comprised of the skew angle compensator 104 and the LC device 105 transforms the polarization field across the illumination pupil such that the light exiting the modified skew angle retarder 104 is substantially P-polarized and hence is transmitted (i.e., rejected) by the PBS 110 back towards the light source 109.
  • the polarization transformation effected by the modified skew angle compensator 104 and the retardance of the LC device substantially prevents the dark-state light from being reflected by the PBS to the display optics 1 11, and thus improves the contrast of the image.
  • bright-state light undergoes a polarization transformation from P- light to S-light by the LC device and is reflected by the PBS 110 as light 108 to the display optics 111.
  • This process follows from well-known optical principles, and follows from the arrangement of the LCD device 100. As such, it is not further discussed so as to not detract from the focus of the present embodiments.
  • the arrangement of elements of the LCD device 100 is merely illustrative, and other arrangements could be used.
  • the structure of the embodiment of Fig. 1 alternatively could be arranged so that the light first reflected from the PBS onto the LC device and subsequently transmitted through the PBS towards the projection lens.
  • the embodiments described herein could be readily adapted to such an arrangement.
  • Fig. 2 shows schematically the orientation of the slow axes of various retarders that comprise a simplified retarder model of the device 105 of an exemplary embodiment.
  • the LC device is a normally white 45TN0 LCOS mode, which may be used as the device 105.
  • the LCOS device of the exemplary embodiment has two main sources of retardance when voltage driven into the "black" state. The first source is associated with the top substrate LC alignment layer (top rub) of the device and the second source is associated with the silicon substrate LC alignment layer (bottom rub).
  • the molecules of the LC material are given a preferred orientation.
  • the molecules in the 45TN0 are oriented with a relative twist angle of 45° between the bottom and top substrates.
  • the bulk of the molecules Upon application of an electric field, the bulk of the molecules are homeotropically aligned with the field (i.e. parallel to the device normal direction). However, at the top and bottom alignment interfaces, a few layers of the LC molecules are strongly anchored to the alignment layer and are largely unaffected by the applied field, which results in a residual retardance at these interfaces.
  • the LCOS device With the applied electric field driving the LC into the "black” state the LCOS device may be represented by the two retarders 201 and 202, having respective slow axes 207 and 206 as shown.
  • An additional device compensator (retarder) 203 is included with the device to compensate largely for the back rub 201 resulting in a resultant residual device retarder 204, which has a slow axis 208 in a direction that is either parallel or perpendicular to the incident polarization direction (P-polarized).
  • the resultant residual device retarder 204 representing the compensated device is combined with a modified skew-angle compensator to produce an effective quarter wave retarder (half-wave in reflection).
  • the modified skew angle compensator accounts for the anomalous birefringent behavior of the LC device, and together the LC device and the modified skew angle compensator substantially compensate for the geometrical skew angle effects at the PBS.
  • the compensator 203 substantially 'cancels' the retarding effect of the back rub 201 of the LC device producing a residual retardance 204.
  • This residual device retardance is shown in Figs. 3a and 3b, where depending on the orientation of the slow axis of the device (301, 304) and slow axes of the modified skew angle compensator 302,303, the device retardance either adds to (Fig. 3a) or subtracts from (Fig 3b) the modified skew angle compensator 302,303.
  • the skew angle compensator must be modified to account for the residual birefringence of the device.
  • Fig. 4a shows the residual retardance 401 vs. wavelength of a 45TN0 device operating in its "black" state that includes a compensator to cancel the back rub retardance (i.e., essentially only the front rub retardance remains).
  • the retardance of the skew angle retarder retardance should be subtracted from or added to, respectively.
  • Fig. 4b shows the retardance dispersion curves of two sample skew angle retarders 405, 406 over a prescribed spectral range.
  • a skew angle retarder such as that of curve 405, may be used to approximate a retardance as at 403 over a wavelength range of approximately 460 nm to approximately 580 nm.
  • the skew angle retarder of curve 406 may be used over a wavelength range of approximately 550 nm to approximately 570 nm to approximate a retardance as shown at curve 404.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Nonlinear Science (AREA)
  • General Physics & Mathematics (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Chemical & Material Sciences (AREA)
  • Theoretical Computer Science (AREA)
  • Mathematical Physics (AREA)
  • Computer Hardware Design (AREA)
  • Optics & Photonics (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Liquid Crystal (AREA)

Abstract

Dispositif formant modulateur de lumière (105) présentant un premier retardement optique et un couplage optique avec un compensateur modifié d'angles de biais (104) présentant à son tour un deuxième retardement optique, la somme du premier retardement optique et du deuxième retardement optique étant égale au retardement d'un retardateur quart d'onde sur une gamme de longueurs d'onde prédéfinie. Le procédé permettant sensiblement d'éviter toute transmission de lumière à l'état obscur vers l'optique d'affichage (111) dans un afficheur à cristaux liquides consiste à faire tourner la lumière à l'état obscur de sorte qu'un diviseur de faisceau à polarisation (110) réémette la lumière en direction de la source (109).
EP04736437A 2003-06-13 2004-06-09 Compensateur modifie d'angles de biais pour afficheurs a cristaux liquides a retardement residuel Withdrawn EP1636638A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US47869103P 2003-06-13 2003-06-13
PCT/IB2004/050875 WO2004111713A1 (fr) 2003-06-13 2004-06-09 Compensateur modifie d'angles de biais pour afficheurs a cristaux liquides a retardement residuel

Publications (1)

Publication Number Publication Date
EP1636638A1 true EP1636638A1 (fr) 2006-03-22

Family

ID=33551848

Family Applications (1)

Application Number Title Priority Date Filing Date
EP04736437A Withdrawn EP1636638A1 (fr) 2003-06-13 2004-06-09 Compensateur modifie d'angles de biais pour afficheurs a cristaux liquides a retardement residuel

Country Status (6)

Country Link
EP (1) EP1636638A1 (fr)
JP (1) JP2007528010A (fr)
KR (1) KR20060013687A (fr)
CN (1) CN1806193A (fr)
TW (1) TW200510805A (fr)
WO (1) WO2004111713A1 (fr)

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TW412656B (en) * 1996-04-26 2000-11-21 Hitachi Ltd Liquid crystal display
EP1160617B1 (fr) * 2000-05-31 2004-10-13 Sony Corporation Projecteur à cristaux liquides à contraste amélioré

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2004111713A1 *

Also Published As

Publication number Publication date
CN1806193A (zh) 2006-07-19
WO2004111713A1 (fr) 2004-12-23
TW200510805A (en) 2005-03-16
KR20060013687A (ko) 2006-02-13
JP2007528010A (ja) 2007-10-04

Similar Documents

Publication Publication Date Title
EP1764644B1 (fr) Compensateurs de retardation orientés de maniere optimale
US7518662B2 (en) Contrast enhancement for liquid crystal based projection systems
US6340230B1 (en) Method of using a retarder plate to improve contrast in a reflective imaging system
US6398364B1 (en) Off-axis image projection display system
JP3260867B2 (ja) 頭部装着型ディスプレイ
EP0677180B1 (fr) Systeme de retroprojection a ecran a cristaux liquides reflechissant
US6557999B1 (en) System and method for contrast enhancement in projection imaging system
JP5203926B2 (ja) 偏光ビームスプリッタにおける応力複屈折の補償およびそれを使用するシステム
JP2009545773A (ja) 形態複屈折型偏光ビームスプリッタを用いたＬＣｏＳプロジェクションシステム用の補償スキーム
JP2002542509A (ja) 反射型ｌｃｄ用光学系
US20230350247A1 (en) Liquid crystal display with external retarder
CN101546067B (zh) 图像显示装置以及光学补偿设备
Arnold et al. 52.3: An Improved Polarizing Beamsplitter LCOS Projection Display Based on Wire‐Grid Polarizers
JP2003255330A (ja) 液晶表示装置
US6025890A (en) Beam splitter element including a beam splitting layer and a polarizing layer for use in a light polarization modulating display system
US6307607B1 (en) Reflective liquid crystal display with integrated compensation for skew angle rotation and birefringence effects
WO2004111713A1 (fr) Compensateur modifie d'angles de biais pour afficheurs a cristaux liquides a retardement residuel
WO2019244302A1 (fr) Dispositif de compensation optique et dispositif d'affichage à cristaux liquides
WO2007021981A2 (fr) Amelioration de contrastes pour des systemes de projection fondes sur des cristaux liquides
Chen et al. High-contrast MacNeille-PBS-based LCOS projection systems
WO2005091628A1 (fr) Regulation de la luminance dans des systemes de projection a cristaux liquides
JP7472798B2 (ja) 液晶表示装置
WO2001067429A1 (fr) Reglage de la tension de l'etat de polarisation d'un ecran a cristaux liquides
Aastuen et al. Compensation of birefringence in lead‐free polarizing beam splitters for LCOS projectors
Chen et al. Contrast optimization for MacNeille‐PBS‐based LCOS projection systems

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: 20060113

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PL PT RO SE SI SK TR

DAX Request for extension of the european patent (deleted)
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: 20060810