WO2004088362A2 - Moyen de compensation destine a augmenter le rapport de contraste de systemes de projection video a base de lcos - Google Patents

Moyen de compensation destine a augmenter le rapport de contraste de systemes de projection video a base de lcos Download PDF

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Publication number
WO2004088362A2
WO2004088362A2 PCT/US2004/009693 US2004009693W WO2004088362A2 WO 2004088362 A2 WO2004088362 A2 WO 2004088362A2 US 2004009693 W US2004009693 W US 2004009693W WO 2004088362 A2 WO2004088362 A2 WO 2004088362A2
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WO
WIPO (PCT)
Prior art keywords
microdisplay
axis
waveplate
quarter
oriented
Prior art date
Application number
PCT/US2004/009693
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English (en)
Other versions
WO2004088362A9 (fr
WO2004088362A3 (fr
Inventor
Arthur Berman
Original Assignee
Lightmaster Systems, 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 Lightmaster Systems, Inc. filed Critical Lightmaster Systems, Inc.
Priority to TW093109615A priority Critical patent/TW200532319A/zh
Publication of WO2004088362A2 publication Critical patent/WO2004088362A2/fr
Publication of WO2004088362A9 publication Critical patent/WO2004088362A9/fr
Publication of WO2004088362A3 publication Critical patent/WO2004088362A3/fr

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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
    • 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
    • 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
    • G02F1/133638—Waveplates, i.e. plates with a retardation value of lambda/n
    • 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
    • G02F1/136—Liquid crystal cells structurally associated with a semi-conducting layer or substrate, e.g. cells forming part of an integrated circuit
    • G02F1/1362—Active matrix addressed cells
    • G02F1/136277—Active matrix addressed cells formed on a semiconductor substrate, e.g. of silicon
    • 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
    • G02F2413/00—Indexing scheme related to G02F1/13363, i.e. to birefringent elements, e.g. for optical compensation, characterised by the number, position, orientation or value of the compensation plates
    • G02F2413/02—Number of plates being 2
    • 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
    • G02F2413/00—Indexing scheme related to G02F1/13363, i.e. to birefringent elements, e.g. for optical compensation, characterised by the number, position, orientation or value of the compensation plates
    • G02F2413/07—All plates on one side of the LC cell
    • 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
    • G02F2413/00—Indexing scheme related to G02F1/13363, i.e. to birefringent elements, e.g. for optical compensation, characterised by the number, position, orientation or value of the compensation plates
    • G02F2413/08—Indexing scheme related to G02F1/13363, i.e. to birefringent elements, e.g. for optical compensation, characterised by the number, position, orientation or value of the compensation plates with a particular optical axis orientation

Definitions

  • the invention is related to optical devices and more particularly related to LCoS based projection systems.
  • the invention is yet further related to increasing a contrast ratio in an LCoS based display.
  • the projection mechanism within a microdisplay based video projector is called a light engine.
  • the optical heart of the light engine is called the kernel.
  • a generic kernel is composed of a prism assembly and three LCoS microdisplays.
  • An example of a specific kernel 100, a quad type kernel of particular interest to Light aster Systems, is illustrated in Fig, 1. Note that the pixel arrays contained within each of the three microdisplays must be mutually aligned to a high degree of accuracy.
  • Part of the challenge in designing a light engine is to produce an image with the highest possible contrast ratio.
  • the best and usual way by which this is accomplished is to produce the blackest possible dark state. Two of the procedures known to blacken the dark state are discussed below.
  • the first procedure is called skew ray compensation.
  • the purpose of this procedure is to improve the linear polarization of off-axis light rays transmitted by the Polarizing Beam Splitting (PBS) cubes.
  • the method is to place a quarter waveplate in optical series with the output of the PBS such that a principle axis of the waveplate is parallel to the axis of linear polarization of light rays transmitted normal to the face of the PBS.
  • a configuration for skew ray compensation is illustrated in Fig. 2.
  • the optimum compensation will occur when the wavelength at which the value of the retarder is exactly a quarter wave matches the center of the spectrum transmitted by the PBS.
  • the second procedure is to compensate the residual retardation found in the high voltage, dark state of the microdisplay.
  • a configuration for residual retardation compensation is illustrated in Fig. 3.
  • the method provides that the linearly polarized light input to the microdisplay be oriented parallel to the optical "axis" of the microdisplay. This "axis" is typically at a small angle with respect to the mechanical "package" of the microdisplay. The optimum angle is determined by first applying the highest available voltage to the microdisplay.
  • the microdisplay Placed in optical series with the face of the PBS, the microdisplay is then rotated about its Z-axis until the intensity of the reflected light is minimized (as observed at the output of the prism assembly) .
  • the residual retardation compensation method described above specifically applies to LCoS microdisplays that utilize the so-called normally bright, 45° TN, mixed mode electro optic effect. Variations of the method may be needed to compensate the residual retardation in LCoS microdisplays that utilize other electro optic effects.
  • Fig. 4 A way that these conflicting compensation requirements are accommodated in conventional kernel/light engine configurations is illustrated in Fig. 4.
  • the principle axis of the quarter waveplate is mechanically rotated to a compromise angle ⁇ c . It is intermediate between that required for optimum skew ray compensation (0 degrees) and that required for the input of linearly polarized light ( ⁇ 0 ) to optimally accomplish residual retardation compensation in the microdisplay.
  • the exact orientation of the principle axis of the quarter waveplate is determined by minimizing the light reflected from the fully energized microdisplay as observed at the output of the prism assembly. Although effective, this compromise configuration accomplishes neither full skew ray nor residual retardation compensation.
  • the present invention provides a microdisplay package, comprising a microdisplay having an optical axis, and a quarter waveplate coupled to the microdisplay.
  • the quarter waveplate may be cut such that a principle axis of the quarter waveplate is parallel to the optical axis of the microdisplay.
  • the present invention provides a microdisplay package, comprising, a quater waveplate oriented such that a principle axis of the quater waveplate is aligned parallel to reference axis, and a microdisplay device coupled to the quarter waveplate and oriented at an angle ⁇ 0 such that an optical "axis" of the microdisplay is optimally oriented for residual retardation compensation with respect to the linearly polarized light input to the microdisplay from the quarter waveplate when the reference axis is parallel to an axis of linear polarization of light incident to the quarter waveplate.
  • the present invention provides a microdisplay package, comprising, A quater waveplate having a principle axis parallel of a reference axis, a half waveplate having a principle optical axis oriented at an angle of (1/2) ⁇ 0 with respect to the reference axis, and a microdisplay having an optical axis oriented at an angle of ⁇ 0 with respect to the reference axis.
  • the present invention includes a method of skew ray and residual retardation compensation in a microdisplay based device, comprising the steps of, operating on light channel directed to a microdisplay with a quater waveplate oriented such that a principle axis of the quater waveplate is aligned parallel to an axis of linear polarization of the light channel incident upon the quarter waveplate, and modulating the light channel after the quarter waveplate with a microdisplay oriented at an angle ⁇ Q such that an optical "axis" of the microdisplay is optimally oriented for residual retardation compensation with respect to the linearly polarized light input to the microdisplay from the quarter waveplate.
  • the present invetion is also a method of aligning a quarterwaveplate, a half waveplate, and a microdisplay to achieve simulatneaous skew ray and residual retardation compensation, and prism assemblies incorporating the same.
  • Fig. 1 is a drawing of a simplified LCoS based kernel
  • Fig. 2 is a drawing of an orientation of the quarter waveplate to accomplish skew ray compensation
  • Fig. 3 is a drawing of an orientation of a microdisplay to compensate residual retardation in the dark state of the microdisplay
  • Fig. 4 is a drawing of a representation of a compensation method used in conventional LCoS kernels
  • Fig. 5 is a drawing of a representation of a compensation method for LCoS kernels according to an embodiment of the present invention.
  • Fig. 6 is a drawing of a representation of a means to allow the microdisplays in all three channels to rotate in the same direction as observed at the output face of the kernel according to an embodiment of the present invention
  • Fig. 7 is a drawing of a representation of an optimizing waveplate according to an embodiment of the present invention
  • Fig. 8 is a drawing of a representation of another compensation method for LCoS kernels according to an embodiment of the present invention
  • Fig. 9 is a drawing illustrating nomenclature describing a quad style prism; and Fig. 10 is a chart illustrating several example kernel configurations to which one or more aspects of the present invention may be applied.
  • the present inventor has realized the- need to improve the blackness of the dark state of the video image projected by an LCoS based light engine.
  • the present invention simultaneously accomplishes skew ray and residual retardation compensation.
  • the present invention increases the contrast ratio of LCoS microdisplay based video projectors.
  • the improvement is accomplished by "blackening" the dark state of the image.
  • the means utilizes waveplate (s) to optimally and simultaneously perform:
  • a principle axis 510 of the quarter waveplate 500 is aligned parallel to the axis of linear polarization of light rays output normal to the face of the PBS (and input to the quarter waveplate 500) 525. This is the optimum angle for skew ray compensation.
  • the microdisplay 500 is rotated by an angle ⁇ Q such that its optical "axis" is optimally oriented for residual retardation compensation with respect to the linearly polarized light input to the microdisplay 550 from the quarter waveplate 500.
  • ⁇ Q the optimum angle ⁇ 0 for the blue, green and red microdisplays are likely to be at least slightly different. In a real kernel application a reasonable way to accommodate this difference is to optimally align the green microdisplay since the green content of the image is visually dominant.
  • the orientations of the blue and red microdisplays are adjusted (e.g., rotated) to match that of the green.
  • the blue and the red are not fully optimized they will, none-the-less, produce a good dark state, certainly one blacker than if not rotated at all.
  • a further matter of real practical importance to the application of this compensation technology is that, in the quad type prism illustrated in Fig. 1, the 3 microdisplays are viewed through the output face of the prism assembly under slightly different conditions. That is, the green and red microdisplays are viewed after a single reflection while the blue microdisplay is viewed directly. The consequence of this is that, viewed at the output face, a clockwise rotation applied to the 3 microdisplays is observed as a counterclockwise rotation of the green and blue microdisplays and a clockwise rotation of the red microdisplay.
  • the reason that this is important is that, if the green microdisplay is rotated counterclockwise by ⁇ ⁇ to align its optical "axis" with the input linearly polarized light, then the blue and red microdisplays must also rotate counterclockwise (as observed at the output face) so that their pixel arrays coincide. This is fine for the red microdisplay since it is also viewed after one reflection. When rotated counterclockwise by ⁇ 0 , the optical "axis" of the red microdisplay will also be oriented parallel to the input linearly polarized light. Unfortunately, since the blue microdisplay is viewed directly, it is necessary that it rotate clockwise for the pixel array to align with the green and the red microdisplays.
  • the optical "axis" of the red microdisplay is oriented at an angle of 2 ⁇ 0 with respect to the input linearly polarized light. Rather than blackening the dark state of the blue microdisplay, such an orientation will completely destroy the contrast ratio.
  • Fig. 6 A solution to this problem is disclosed in Fig. 6.
  • the orientation of the principle axis of the quarter waveplate is rotated by 90° with respect to the corresponding principle axis of the waveplates in the green and red channels.
  • a clockwise rotation of the blue microdisplay to the desired angle ⁇ 0 now blackens the dark state of the blue channel in a manner similar to that produced in the green and red channels.
  • Fig. 1 represents an example kernel configuration that has an arrangement of optical components in which the invention may be applied. Many different arrangements of optical components may be utilized along with the techniques of the invention described herein to produce functionally equivalent kernels.
  • Fig. 9 is a diagram illustrating a naming convention for faces of a kernel
  • Fig. 10 is a tabular listing of kernel configurations that are also applicable to the present invention and are described using the naming conventions established in Fig. 9.
  • the various configurations utilize different arrangements of dichroics, wavelength specific retarders (e.g., color selects) , and polarizers as appropriate for the particular kernel configuration, and such arrangements which will be apparent to those of ordinary skill in the art after review of the present disclosure.
  • the kernel 100 matches the #2 kernel configuration of Fig. 10 (a right angle input and the microdisplays mounted on faces according to kernel configuration #2) .
  • the quarter waveplates and microdisplays are oriented as described above (a principle axis of skew ray quarter waveplates in the green and blue channels are parallel to the axis of linearly polarized input light, and perpendicular in the blue channel; and the blue microdisplay is counter rotated compared to the green and red microdisplays) .
  • the skew ray quarter waveplates for the red and blue channels are oriented at 90 degrees, and their microdisplays are counter rotated compared to the green microdisplay orientation.
  • the orientation of the skew ray quarter waveplates are swapped such that the red and blue channel quarter waveplates are oriented parallel to the axis of linearly polarized input light and the green channel, skew ray quarter waveplate is oriented at 90 degrees to the axis of linearly polarized input light. Therefore, as noted above, the preferred orientations of Fig. 10 include channels where the green channel shares a same number of reflections as a second channel, and, the green channel and second channel quarter waveplates are arranged with their principle axes parallel to the axis of linearly polarized input light.
  • the present invention is utilized in a prism assebly in which the main optical components of the prism assembly (beam splitters) are liquid coupled.
  • the beam splitters are set, for example, in prism assembly pathlength matched positions with joints between the beamsplitters.
  • the joints are filled with liquid (e.g., an index matching fluid).
  • a frame and/or a mounting plate in co juction with an adhesive or other seal maintains the fluid within the prism assebly.
  • Optical flats such as color selects (e.g., a product by ColorLink Corporation) , dichroics, wavelength specific retarders, if needed for the prism assembly design, may also be inserted into the joints and immersed in the index matching fluid.
  • the beam splitters may each comprise 2 prisms abutted on their diagonals and set in beamsplitter pathlength matched positions.
  • a beam splitting layer is disposed on one or both of the diagonals.
  • the beam splitting layer may be any of, for example, a polarizing beam splitting thin film (a PBS beamsplitter) , a single color cholesteric layer, two cholestric layers of different colors (Cholesteric based Beam Splitters - CBSs) , a dichroic layer, or any other material that can perform beam splitting.
  • a principle optical axis of the quarter waveplate 820 is aligned parallel to the axis of the linearly polarized light output normal to the face of the PBS.
  • a half waveplate 840 is oriented at an angle of ⁇ 0 with respect to a principle optical axis of the quarter waveplate.
  • the effect of the half waveplate is to rotate the axis of the input linearly polarized light to an angle ⁇ 0 .
  • Linearly polarized light with its axis oriented at ⁇ 0 is optimum input for residual retardation compensation in the microdisplay - without the need to rotate the microdisplay.
  • a retarder may be composed of a quarter waveplate bonded to a half waveplate with their principle optical axes aligned at an angle of ⁇ Q with respect to each other. In this case the microdisplay would be mounted without mechanical rotation.
  • an integrated package may be constructed of a waveplate, a ⁇ waveplate, and a microdisplay ' all precisely mounted according to the orientations shown in Fig. 8. Without reliably reproduced residual retardation, then there are at least two configurational possibilities.
  • a first is to use the bonded waveplates (H waveplate and waveplate) just discussed but to rotate the microdisplay about its Z-axis to obtain the blackest possible dark state.
  • a second is to maintain the microdisplay in the vertical orientation but to rotate the half waveplate about its Z-axis to obtain the blackest possible dark state.
  • the present invention provides a prism assembly comprising: optical components arranged to manage first, second, and third light channels through a portion of the prism assembly and combine the first, second, and third channels prior to exiting an output face of the prism assembly; a first quarter waveplate placed in the first light channel and oriented such that a principle axis of the first quarter waveplate is aligned parallel to the axis of linearly polarized light input to the first quarter waveplate; a second quarter waveplate placed in the second light channel and oriented such that a principle axis of the second quarter waveplate is aligned parallel to the axis of linearly polarized light input to the second quarter waveplate; a third quarter waveplate placed in the third light channel and oriented such that a principle axis of the third quarter waveplate is aligned perpendicular to the axis of linearly polarized light input to the third quarter waveplate.
  • the prism assembly may then be fitted with microdisplays to become a kernel, this example embodiment further comprising: a first microdisplay located in the first light channel in an orientation that aligns an optical axis of the first microdisplay with the axis of linearly polarized light input to the first microdisplay; a second microdisplay located in the second light channel in an orientation that aligns an optical axis of the second microdisplay with the axis of linearly polarized light input to the second microdisplay; and a third microdisplay located in the third light channel in an orientation that aligns an optical axis of the third microdisplay with the axis of linearly polarized light input to the third quarter waveplate.
  • the example embodiment may include, for example, wherein one of the 1st and 2nd microdisplays is a microdisplay to be activated with a green content portion of video and image data, and/or wherein one of the 1st and 2nd channels is a green light channel.
  • a prism assembly comprising:
  • microdisplays are attached to the prism assembly, each individually positioned in a respective one of the light channels and an axis of each microdisplay is parallel to an axis of polarized light input to the quarter waveplate of the same channel.
  • a waveplate is introduced to effectively rotate an axis of linear polarization of input light to match an optical axis of a corresponding microdisplay.
  • the present invention may suitably comprise, consist of, or consist essentially of, any of element (the various parts or features of the invention) and their equivalents. Further, the present invention illustratively disclosed herein may be practiced in the absence of any element, whether or not specifically disclosed herein. Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, ' the invention may be practiced otherwise than as specifically described herein.

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  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Mathematical Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Optical Elements Other Than Lenses (AREA)
  • Transforming Electric Information Into Light Information (AREA)

Abstract

L'invention concerne un dispositif de composants optiques et leur orientation qui exécute une compensation de rayons obliques et une réduction du retard résiduel dans des afficheurs à base de LcoS. Un axe principal d'une lame quart d'onde orientée est aligné parallèle à un axe de référence, et un microafficheur est couplé à la lame quart d'onde et orienté à un angle υo de façon qu'un « axe » optique du microafficheur soit orienté de manière optimale pour la compensation du retard résiduel par rapport à l'entrée de lumière à polarisation linéaire du microafficheur à partir de la lame quart d'onde lorsque l'axe de référence est parallèle à un axe de polarisation linéaire de la lumière incidente vers la lame quart d'onde. Une lame quart d'onde et une demi-lame d'onde sont orientées à ½ thêta et un microafficheur à un angle thêta. Un ensemble prisme est réalisé au moyen de blocs de microafficheurs qui exécutent simultanément une compensation de rayons obliques et de retard résiduel.
PCT/US2004/009693 2003-03-28 2004-03-29 Moyen de compensation destine a augmenter le rapport de contraste de systemes de projection video a base de lcos WO2004088362A2 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
TW093109615A TW200532319A (en) 2004-03-29 2004-04-07 Means of compensation to increase the contrast ratio of LCoS based video projection systems

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US45891703P 2003-03-28 2003-03-28
US60/458,917 2003-03-28

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WO2004088362A9 WO2004088362A9 (fr) 2005-07-28
WO2004088362A3 WO2004088362A3 (fr) 2005-09-09

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020001135A1 (en) * 2000-03-27 2002-01-03 Berman Arthur L. High efficiency prism assembly for image projection
US20030103171A1 (en) * 2001-12-03 2003-06-05 Hall Estill Thone Light valve projector architecture
US6717706B2 (en) * 2000-08-31 2004-04-06 Cambridge Research And Instrumentation, Inc. State of polarization detector

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020001135A1 (en) * 2000-03-27 2002-01-03 Berman Arthur L. High efficiency prism assembly for image projection
US6717706B2 (en) * 2000-08-31 2004-04-06 Cambridge Research And Instrumentation, Inc. State of polarization detector
US20030103171A1 (en) * 2001-12-03 2003-06-05 Hall Estill Thone Light valve projector architecture

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WO2004088362A9 (fr) 2005-07-28
WO2004088362A3 (fr) 2005-09-09

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