WO1995035486A1 - Dispositif de filtrage optique et application a un projecteur a cristal liquide - Google Patents
Dispositif de filtrage optique et application a un projecteur a cristal liquide Download PDFInfo
- Publication number
- WO1995035486A1 WO1995035486A1 PCT/FR1994/000733 FR9400733W WO9535486A1 WO 1995035486 A1 WO1995035486 A1 WO 1995035486A1 FR 9400733 W FR9400733 W FR 9400733W WO 9535486 A1 WO9535486 A1 WO 9535486A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- filtering device
- wavelengths
- holographic
- hcc
- liquid crystal
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/10—Beam splitting or combining systems
- G02B27/14—Beam splitting or combining systems operating by reflection only
- G02B27/145—Beam splitting or combining systems operating by reflection only having sequential partially reflecting surfaces
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/32—Holograms used as optical elements
-
- 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
- G02F1/133509—Filters, e.g. light shielding masks
-
- 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
- G02F1/133509—Filters, e.g. light shielding masks
- G02F1/133514—Colour filters
-
- 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
- G02F1/1336—Illuminating devices
- G02F1/133621—Illuminating devices providing coloured light
Definitions
- the invention relates to an optical filtering device and its application to a liquid crystal projector, making it possible in particular to carry out chromatic correction.
- These devices operate on the same principle as a slide projector in which it has been replaced by a liquid crystal valve. They generally include three cells, one for each of the primary colors (red, green, blue) from the same white light source.
- the objective being to achieve a good quality image, the main criteria for evaluating the image will be the following:
- the invention therefore relates to an optical filtering device comprising a dichroic separator located on the path of a beam to be filtered, characterized in that it comprises a holographic filtering device also located on the path of the beam to be filtered.
- the invention also relates to a liquid crystal projector applying the device, characterized in that it comprises: a source emitting in a range of wavelengths comprising several primary wavelengths of the range of colors;
- - at least one holograic filtering device eliminating unwanted wavelengths
- - at least one dichroic separator separating the ranges of wavelengths corresponding to ranges of wavelengths of different primary colors
- FIG. 10 a typical example of a color diagram generated by a matrix of color filters known in the art
- This device comprises a dichroic separation device or dichroic mirror MD and a holographic HCC filtering device.
- a light probe L provides an IF beam to be filtered which is received by the dichroic mirror. This reflects light F2 having a determined length range and which is transparent to light F'2 having a wavelength not contained in this range.
- the filtering selectivity of the dichroic mirror is limited and the characteristics of the source S can shift in the wavelengths. Filtering may therefore prove to be insufficient.
- the invention therefore provides for combining with the dichroic mirror an HCC holographic filtering device mainly consisting of a layer of photosensitive material in which at least one network of strata has been recorded making it possible to reflect the unwanted wavelengths (beam F ′ 3 ) and to be transparent (beam F3) to the range of wavelengths that it is desired to obtain.
- the HCC filtering device has been registered to reflect certain undesirable lengths around the wavelength to be obtained. However, as the source ages its characteristics may change and there may be an undesirable change in colorimetry. Similarly, the replacement of a source with another part can lead to an IF beam having different undesirable lengths. In these two cases, to adapt the filtering, the HCC device is rotated relative to the direction of the beam F2.
- ⁇ is the step of the registered interference fringes n 0 is the average index of the HCC medium ⁇ is the angle of incidence of the beam F2 with the plane of incidence of the device HCC k is the order of diffraction ⁇ is the wavelength of the beam F2.
- the network having been registered, the step ⁇ is fixed.
- the thickness d of the layer of photosensitive material is preferably greater than or equal to or even significantly greater than no ⁇ 2 / 2 ⁇ .
- the HCC device is made of materials as indicated in the documents: - "Hologram recording with new photopolymer System" R.T. Ingman,
- FIGS. 7a, 7b, 7c clearly show that the possible deviations from the ideal filtering considerably reduce the palette of available colors and require corrections on the video signal to restore the correct dominants of the images. video.
- HCC correction filter
- FIG. 9 A practical embodiment of this type of filter is given in FIG. 9 with a material having an index variation of 0.03 and a thickness operating at Bragg incidence of 5 ° for the wavelength 575 nm.
- This component used at the incidence of 7 ° (optimal filtering for the wavelength of 580 nm) leads to the same light balance and to a difference of less than 1/1000 on the chromaticity coordinates.
- FIG. 11 represents an application of the filtering device according to the invention to the production of a color liquid crystal projector.
- Such a projector must have a liquid crystal cell by primary color (red, green, blue).
- FIG. 11 there is therefore the LCDR cell for the red, the LCDV cell for the green, and the LCDB cell for the blue.
- an optical focusing device LCR, LCV, LCB and a holographic filtering device HCCR, HCCV, HCCB In series with each cell is placed, an optical focusing device LCR, LCV, LCB and a holographic filtering device HCCR, HCCV, HCCB.
- Each assembly consisting of a cell and a holographic filtering device receives a beam which is in principle monochrome in a given range of wavelengths.
- the holographic filtering devices are placed upstream of the crystal cells with respect to the directions of the light beams to be treated, but they could be placed downstream.
- the different light beams are obtained, from a single source S, by separation of different ranges of wavelengths contained in the emission spectrum of the source S and this using dichroic separators.
- dichroic mirrors are used.
- the MDR dichroic mirror receives the beam from the source S and reflects the light FR of wavelengths included in the wavelength range of red.
- the beam FR is sent by a mirror M1 to the holographic filtering device HCCR and the liquid crystal cell LCDR.
- the light not reflected by the MDR mirror is transmitted to a second dichroic mirror MDV1 which reflects the light FV included in the wavelength range of green.
- the FV beam is sent by the HCCV holographic filtering device and to the LCDV cell.
- the different sets of holographic filtering devices / liquid crystal cells HCCR / LCDR, HCCV / LCDV, HCCB / LCDB transmit beams with red, green and blue wavelengths respectively. These different beams are recombined by a dichroic blade MDV2 reflecting green (combination of red and green) and by a dichroic blade reflecting blue (combination of blue with red and green).
- a projection optic OP then makes it possible to project the color image resulting from the combination of the images displayed by the liquid crystal cells LCDR, LCDV, LCDB.
- FIG. 11 The architecture of the system in FIG. 11 has been given by way of example, but any other arrangement could be provided for combining the beams of the different holographic filtering device / liquid crystal cell assemblies.
- FIG. 12 shows another embodiment of the device of the invention in which the HCCR, HCCV and HCCB filtering devices are not associated with the liquid crystal cells LCDR, LCDV and LCDB but are grouped together at the output of the device.
- the HCCR, HCCV and HCCB devices could be provided between the source S and the first dichroic mirror MDR.
- the holographic filtering devices HCCR, HCCV and HCCB can be oriented so as to modify the angle of incidence of each beam incident on the input face of each device HCCR, HCCV , HCCB and to modify the wavelength ranges for which there is diffraction in these devices.
- devices for measuring color fluxes DECR, DECB, DECV are provided, detecting the undesirable wavelengths and each controlling the orientation of the filtering devices HCCR, HCCB, HCCV accordingly (see figure 11).
- a sensing element may be used arranged on the active matrix of the corresponding liquid crystal cell (LCDR, LCDG, LCDB).
- the detection devices can also be grouped into a DECG measurement device as indicated by dotted lines in FIG. 11 or as shown in FIG. 12.
- the holographic components necessary for chromatic correction are obtained by holographic recording of simple functions of the mirror type and can be duplicated by optical copying means.
- the physical parameters of the component, thickness and variation of index determine the spectral width of the band to be filtered.
- holographic correction components when they operate near normal incidence have the advantage of having identical filtering characteristics for the two polarization components. This therefore allows compensation, without loss of flux, for the differences in spectral reflectivity existing between the two polarization components inherent in the use of dichroic components at incidences> 20 °.
- the projection device of the invention therefore makes it possible, by the use of holographic color correcting components, to simply adjust the chromaticity coordinates of the three primaries R, G, B, of a liquid crystal projector.
- This device consists mainly of a white light source (S), dichroic mirrors for the separation of primaries and holographic components intended for chromatic corrections.
- S white light source
- dichroic mirrors for the separation of primaries
- holographic components intended for chromatic corrections.
- the color image is then obtained by one of the means of known art (front or rear projection) O 95/35486 PC17FR94 / 00733
- the holographic correction components are preferably used in the vicinity of the normal incidence and of the photoinduced phase structure type (modulation of the index of a medium of a few tens of microns thick). As the lamps age, changes in their colorimetric content may appear. It can easily be envisaged to carry out the necessary corrections by rotation of the holographic components in the same way as one carries out gain corrections in the color cathode-ray tubes.
- This type of servo-control has the advantage of also making it possible to use sources with a spectrum of lines, or else three sources emitting narrow spectral lines.
- the chromatic correction device which is the subject of this patent can also be integrated into a monochrome liquid crystal projector, comprising a screen provided either with colored filters or with holographic microlenses intended for spatio-chromatic focusing of the lighting source. . Under these conditions, it is possible to overcome the main drawback of monochrome devices, namely the lack of spectral purity of the primers generated by the color filters.
Abstract
Description
Claims
Priority Applications (8)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR9215382A FR2699688B1 (fr) | 1992-12-21 | 1992-12-21 | Dispositif de filtrage optique et application à un projecteur à cristal liquide. |
US08/596,137 US5946114A (en) | 1994-06-17 | 1994-06-17 | Optical filtering device and application to a liquid crystal projector |
PCT/FR1994/000733 WO1995035486A1 (fr) | 1992-12-21 | 1994-06-17 | Dispositif de filtrage optique et application a un projecteur a cristal liquide |
JP50171096A JP3778364B2 (ja) | 1994-06-17 | 1994-06-17 | 濾光装置およびその液晶プロジェクタへの応用 |
EP94919729A EP0714504B1 (fr) | 1994-06-17 | 1994-06-17 | Projecteur a cristal liquide avec dispositif holographique de filtrage |
DE69416840T DE69416840T2 (de) | 1994-06-17 | 1994-06-17 | Flüssigkristallprojektor mit holographischer filtervorrichtung |
KR1019960700808A KR100330109B1 (ko) | 1994-06-17 | 1994-06-17 | 광학필터링장치및액정프로젝터 |
KR1019960700803A KR0161347B1 (ko) | 1993-08-24 | 1994-08-11 | 컵형상 태핏 |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR9215382A FR2699688B1 (fr) | 1992-12-21 | 1992-12-21 | Dispositif de filtrage optique et application à un projecteur à cristal liquide. |
PCT/FR1994/000733 WO1995035486A1 (fr) | 1992-12-21 | 1994-06-17 | Dispositif de filtrage optique et application a un projecteur a cristal liquide |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1995035486A1 true WO1995035486A1 (fr) | 1995-12-28 |
Family
ID=26229975
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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PCT/FR1994/000733 WO1995035486A1 (fr) | 1992-12-21 | 1994-06-17 | Dispositif de filtrage optique et application a un projecteur a cristal liquide |
Country Status (1)
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WO (1) | WO1995035486A1 (fr) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5917561A (en) * | 1996-10-31 | 1999-06-29 | Sony Corporation | Liquid-crystal image projecting apparatus having a color purity correction filter |
WO2000076223A1 (fr) * | 1999-06-04 | 2000-12-14 | Koninklijke Philips Electronics N.V. | Systeme d'affichage par projection couleur a variation de couleurs reduite |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS63147135A (ja) * | 1986-12-10 | 1988-06-20 | Konica Corp | レ−ザ−光量安定化装置 |
US4752130A (en) * | 1986-10-24 | 1988-06-21 | The University Of Rochester | Optical systems utilizing a volume transmission diffraction element to provide wavelength tuning |
EP0383646A1 (fr) * | 1989-02-07 | 1990-08-22 | Thomson-Csf | Dispositif de visualisation à haute définition, en couleur |
-
1994
- 1994-06-17 WO PCT/FR1994/000733 patent/WO1995035486A1/fr active IP Right Grant
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4752130A (en) * | 1986-10-24 | 1988-06-21 | The University Of Rochester | Optical systems utilizing a volume transmission diffraction element to provide wavelength tuning |
JPS63147135A (ja) * | 1986-12-10 | 1988-06-20 | Konica Corp | レ−ザ−光量安定化装置 |
EP0383646A1 (fr) * | 1989-02-07 | 1990-08-22 | Thomson-Csf | Dispositif de visualisation à haute définition, en couleur |
Non-Patent Citations (1)
Title |
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PATENT ABSTRACTS OF JAPAN vol. 12, no. 411 (P - 779) 31 October 1988 (1988-10-31) * |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5917561A (en) * | 1996-10-31 | 1999-06-29 | Sony Corporation | Liquid-crystal image projecting apparatus having a color purity correction filter |
WO2000076223A1 (fr) * | 1999-06-04 | 2000-12-14 | Koninklijke Philips Electronics N.V. | Systeme d'affichage par projection couleur a variation de couleurs reduite |
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