WO2010068974A1 - Moteur optique pour projection miniature utilisant un système de recyclage de polarisation rétroréfléchissant et panneau cls à filtre séquentiel ou coloré à champ réfléchissant - Google Patents

Moteur optique pour projection miniature utilisant un système de recyclage de polarisation rétroréfléchissant et panneau cls à filtre séquentiel ou coloré à champ réfléchissant Download PDF

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Publication number
WO2010068974A1
WO2010068974A1 PCT/AU2009/001622 AU2009001622W WO2010068974A1 WO 2010068974 A1 WO2010068974 A1 WO 2010068974A1 AU 2009001622 W AU2009001622 W AU 2009001622W WO 2010068974 A1 WO2010068974 A1 WO 2010068974A1
Authority
WO
WIPO (PCT)
Prior art keywords
light
lcos
optical engine
reflected
led
Prior art date
Application number
PCT/AU2009/001622
Other languages
English (en)
Inventor
Danny Jung
Peter Rubinshtein
David Kessler
Original Assignee
Digislide Holdings Limited
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
Priority claimed from AU2008906427A external-priority patent/AU2008906427A0/en
Application filed by Digislide Holdings Limited filed Critical Digislide Holdings Limited
Publication of WO2010068974A1 publication Critical patent/WO2010068974A1/fr

Links

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B19/00—Condensers, e.g. light collectors or similar non-imaging optics
    • G02B19/0033—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use
    • G02B19/0047—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use for use with a light source
    • G02B19/0061—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use for use with a light source the light source comprising a LED
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B19/00—Condensers, e.g. light collectors or similar non-imaging optics
    • G02B19/0004—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed
    • G02B19/0009—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed having refractive surfaces only
    • G02B19/0014—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed having refractive surfaces only at least one surface having optical power
    • 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
    • G02B27/09—Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for
    • G02B27/0938—Using specific optical elements
    • G02B27/095—Refractive optical elements
    • G02B27/0955—Lenses
    • G02B27/0961—Lens arrays
    • 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
    • G02B27/09—Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for
    • G02B27/0938—Using specific optical elements
    • G02B27/0994—Fibers, light pipes
    • 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
    • G02B27/28—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising
    • G02B27/283—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising used for beam splitting or combining
    • 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
    • G03B21/14—Details
    • G03B21/20—Lamp housings
    • G03B21/2073—Polarisers in the lamp house
    • 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
    • G03B21/14—Details
    • G03B21/20—Lamp housings
    • G03B21/208—Homogenising, shaping of the illumination light
    • 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]
    • H04N9/3141—Constructional details thereof
    • H04N9/315—Modulator illumination systems
    • H04N9/3167—Modulator illumination systems for polarizing the light beam

Definitions

  • the present invention relates to an optical engine for a projection system and in particular for a miniaturised device in which a projected image is provided by the use of white or coloured light sources, a light collection system, a light shaping system, a polarisation recycling system, a polarising plate beam splitter, an LCoS (Liquid Crystal On Silicon) panel and an image projection system.
  • the projection optics may also incorporate a cylindrical surface to compensate for aberrations caused by the plate beam splitter.
  • Optical engines for image projection utilising reflective LCoS panels are well known.
  • the engines comprise illumination systems to illuminate an LCoS panel and projection systems to project the image from the panel onto a screen.
  • the illumination system typically has one of three basic configurations
  • a colour cluster LED emitting light through a concentrator and/or lenses and a polarising beam splitter where one component of the polarised light is then reflected or transmitted onto a field sequential LCoS panel.
  • the colour LED's are switched in sequence with the image generating electronics system to ensure colour synchronisation.
  • Each of the individual light beams hits a designated LCoS micro-device.
  • Each micro-device has a liquid crystal layer that is sandwiched between a clear thin- film transistor (TFT) and a silicon semiconductor. The coloured beam passes through polarising filters to strike the micro-device.
  • TFT thin- film transistor
  • the liquid crystal acts as a control device that manages the amount of light which hits the pixelated reflective surface of the silicon semiconductor. The more voltage a particular pixel receives, the more light it allows to pass through.
  • the light reflected from the LCoS panel is directed through a projection system comprising a projector lens with focus mechanism, and viewed on an external screen.
  • the present invention is for an optical engine that uses a reflective LCoS colour panel to produce an image and a four or five element projection lens to project this image onto a screen.
  • This LCoS panel is illuminated by a high brightness LED via a concentrator or two condenser lenses, a lenslet array with a prepolariser and combiner lenses by the critical imaging method.
  • a polarising plate beamsplitter acts to reflect this light onto the LCOS.
  • the LCOS changes the state of the polarised light and it is then transmitted through the beamsplitter and the projection optics onto the screen.
  • an optical engine apparatus for the production of an image using an LCoS said apparatus including: a light source to emit light, the light passing through a concentrator and into a symmetrical lenslet array and then an adjacent pre-polariser, some of the light reflected back along the same path from the prepolariser to the light source to be emitted a second time and some of the light being transmitted through the pre-polariser.
  • the light source is a white LED including a diffuse phosphor coating that absorbs and re-emits the reflected light.
  • the light passing through the pre-polariser then passes through combiner lenses, a beamsplitter, and onto the LCoS, a field lens and a plurality of projector lenses and an aperture to project an image onto a surface.
  • the optical engine further includes a window to protect the projector lenses.
  • an optical engine including a LCoS panel to produce an image, said panel adapted to be illuminated by a high brightness LED, there extending between the LED and the panel a symmetrical lenslet array closely coupled to a pre-polariser wherein at least some of the light is reflected from the pre-polariser back through the lenslet array and into the LED to be absorbed and re- emitted a second time.
  • an optical engine for image projection including: a light source adapted to emit a light, the light passing through a concentrator or condenser lenses and onto a lenslet array and then through a pre-polarizer; some of the light being reflected back through the lenslet array and to the light source to be absorbed and re-emitted, the rest of the light now pre-polarised light passing through combiner lenses adapted to provide critical imaging so that the light is then reflected to an LCoS panel by a polarising plate beam-splitter wherein the reflected light from the LCoS panel changes the state of polarisation, the changed light then passing back through the beam splitter and through projection optics onto a screen.
  • the light is a white LED or colour cluster.
  • the beam splitter is a cube beam splitter.
  • optical engine is adapted to be embedded in a mobile device such as but not limited to the group including mobile phones, PDA's, laptops, calculators, GPS devices.
  • a method of producing an image using a LCoS including passing light emitted from a LED through a lenslet array and then through a pre-polariser wherein some of the light is adapted to be reflected back to the LED wherein it is absorbed and re-emitted, the light passing through the pre-polariser being reflected from a beamsplitter and onto the LCoS where it is reflected and the direction of polarisation changed so that the reflected light from the LCoS passes through the beamsplitter and then through projection lenses to be projected onto a surface.
  • FIG 1 illustrates schematically the optical engine of the present invention
  • Figure 2 illustrates schematically the optical engine working in a reflection mode
  • Figure 3 illustrates schematically the optical engine with the polarising cube beamsplitter instead of a polarising plate beamsplitter
  • Figure 4 illustrates schematically the optical engine with condenser lenses rather than a concentrator
  • Figure 5 illustrates the light cone from the lenslet array
  • Figure 6 illustrates the lenslet array at the entrance pupil of the combiner lenses and the LCoS at the focal plane.
  • a high brightness white LED 1 and concentrator 2 are used to illuminate a lenslet array 3.
  • a prepolariser/recycler 4 located at the exit of the lenslet array 3 transmits s polarised light and works with the lenslet array 3 to retro-reflect p polarised light.
  • This p polarised light is returned to the LED 1 via the concentrator 2 where some of it is depolarised and reflected to be recycled and added to the light emitted by the LED 1.
  • the lenslet array 3 has a lenslet aspect ratio of 4:3 to match the aspect ratio of the
  • LCoS panel 6 Each lenslet of the array projects a rectangular cone of light.
  • the two combiner lenses 5 superimpose all these cones of s polarised light onto the LCOS panel 6 via reflection by beamsplitter 8.
  • This illumination method of critical imaging is more efficient than Koehler illumination because the light is shaped into the correct aspect ratio to suit the LCoS panel 6.
  • the LCoS panel 6 is also illuminated more uniformly.
  • the field lens 7 is part of the overall optical design to assist in minimizing the size of the optical engine whilst ensuring the LCoS panel 6 receives telecentric light.
  • the s polarised light is changed to p polarised light by the LCoS pixels in their on-state. This p light then passes through the beamsplitter, projection optics 9, aperture 10 and window 11 onto the screen (not shown).
  • the window has a cylindrical surface to compensate for the field independent astigmatism induced by the plate beamsplitter.
  • the plate beamsplitter 8 is replaced with a cube beamsplitter.
  • the cylindrical surface on the window 11 would then not be necessary.
  • the cube beamsplitter entry/exit faces could incorporate some of the lens surfaces thereby reducing complexity.
  • condenser lenses 2 are used to illuminate the lenslet array 3.
  • the optical engine in the present invention uses a Himax SVGA LCoS colour panel which is illuminated with polarized telecentric light from a high brightness white LED via condenser lenses, a lenslet array, combiner lenses and a polarizing beamsplitter.
  • the image displayed on the LCoS is projected onto a wall or screen with a projection lens which allows for focussing of the projected image from a distance of 500mm to infinity.
  • it can be divided into five groups of components and the following explanation details the function of each group. The design of each group must be in such a manner that they work correctly with the other groups to maximize efficiency.
  • the five groups of components are • LED and condenser lenses or modified concentrator • Lenslet array and prepolarizer/recycler
  • the high brightness white LED 1 is the light source for the projector.
  • the role of the condenser lenses or concentrators 2 is to collect light emitted from the LED and illuminate the entrance side of the lenslet array 3.
  • the design goal of the condenser lenses is to collect as much light as possible from the LED and illuminate the lenslet array within the array's acceptance angle and aperture. This acceptance angle is determined by the design of the lenslet array 3. Any light incident on the array outside this angle is lost.
  • the aperture is determined by the design of the combiner lenses 5.
  • the condenser lens design must also take into account the package size and emitting surface area of the selected LED.
  • the function of the lenslet array is to convert the light incident on the entrance side into light with the same aspect ratio as the LCoS panel 6 and together with the combiner lenses provide an area of light with uniform intensity and the correct size at the LCoS.
  • Figures 3 and 4 show an individual lenslet in one plane only.
  • One explanation to describe the manner in which a lenslet works is to consider that the lens surface on the exit side acts to project an image of a virtual illuminated plane located at the entrance side out to infinity.
  • the lens surface on the entrance side acts as a field lens to refract a cone of light towards the exit lens surface. If each lens surface is rectangular with an aspect ratio of 4:3 then the output angle has the same ratio, i.e. 10 x 13 degrees.
  • a reflective prepolarizer 4 is located 0.5 mm on the exit side of the array. This component transmits light polarized in one plane and reflects the other. As the lenslet array is symmetrical, the reflected light retraces the same path and returns to the LED. The principle of polarization recycling is utilized by this arrangement. The returned light is depolarized and reflected by the white diffuse phosphor surface of the LED back to the prepolarizer to repeat the process.
  • the purpose of the combiner lenses 5 is to collect the light from the lenslet array and superimpose each lenslet's output at the LCoS.
  • Figure 5 illustrates the light cone from two individual lenslets.
  • the lenslet 20 passes the light through prepolarizer 22, through combiner lenses 24 field lens 26 and to the LCoS 28.
  • the polarizing beamsplitter has been omitted for clarity.
  • the second function of the combiner lenses is to provide this light as telecentric illumination at the LCoS.
  • Figure 6 illustrates the lenslet array at the entrance pupil of the combiner lenses and the LCoS at the focal plane. Thus the light from the lenslet apertures 30 is telecentric at LCoS 32.
  • a field lens 7 is used to reduce the airspace between the lenslet array and the first combiner lens and thus reduce overall size of the optical engine.
  • the LCoS is a reflective component and therefore the back focal length of the illumination system and the projector lens must overlap. This is achieved by the use of the polarizing beamsplitter 8.
  • the beamsplitter reflects s-polarized light from the lenslet array and prepolarizer via the combiner lenses onto the LCoS panel.
  • the pixels which are in their "on” state rotate the plane of polarization from s to p and are reflected back towards the beamsplitter. Light reflected by pixels in the "off state maintain their s polarized condition.
  • the beamsplitter now functions as an analyser, transmitting p light from "on” pixels and reflecting s light from "off pixels.
  • the function of the projection lenses 9 is to project the image on the LCoS onto a wall or screen.
  • the focal length is chosen to give a particular size image at a certain distance and the focal ratio must match the focal ratio of the combiner lenses. This lens must also move to allow for focussing at a range of distances.
  • the design of the projector lens must be telecentric at the LCoS. A cylindrical component is included in the projector lens design to compensate for the astigmatism introduced by the beamsplitter.

Abstract

La présente invention concerne un moteur optique pour un système de projection et en particulier pour un dispositif miniaturisé dans lequel une image projetée est produite par l'utilisation de sources de lumière blanche ou colorée, d'un système de collecte de la lumière, d'un système de mise en forme de la lumière, d'un système de recyclage de polarisation, d'un diviseur de faisceau à plaque polarisante, d'un panneau CLS (cristaux liquides sur silicium) et d'un système de projection d'images. Les optiques de projection peuvent également intégrer une surface cylindrique pour compenser les aberrations provoquées par ledit diviseur de faisceau. Le système de recyclage assure l'efficacité du moteur, la lumière qui ne passe pas à travers le prépolariseur étant renvoyée par réflexion le long du chemin optique vers la source de lumière, où elle est absorbée et à nouveau émise. Cela est obtenu par un réseau de petites lentilles symétriques qui est étroitement couplé au prépolariseur.
PCT/AU2009/001622 2008-12-15 2009-12-15 Moteur optique pour projection miniature utilisant un système de recyclage de polarisation rétroréfléchissant et panneau cls à filtre séquentiel ou coloré à champ réfléchissant WO2010068974A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AU2008906427 2008-12-15
AU2008906427A AU2008906427A0 (en) 2008-12-15 An optical engine for miniature projection

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WO2010068974A1 true WO2010068974A1 (fr) 2010-06-24

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102004321A (zh) * 2010-08-27 2011-04-06 浙江金成科技发展有限公司 具有单个偏振转换器的led液晶投影机的光学结构
CN103221735A (zh) * 2010-11-17 2013-07-24 Nec显示器解决方案株式会社 光源设备、照明设备和投影型显示设备
CN111602084A (zh) * 2018-01-18 2020-08-28 苹果公司 空间复用方案
US11493606B1 (en) 2018-09-12 2022-11-08 Apple Inc. Multi-beam scanning system

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5898521A (en) * 1995-11-17 1999-04-27 Matsushita Electric Industrial Co., Ltd. LCD Projector
KR20020039798A (ko) * 2000-11-22 2002-05-30 김순택 3개의 컬러 휠을 구비한 프로젝션 시스템
US20030086066A1 (en) * 2001-11-02 2003-05-08 Nec Viewtechnology, Ltd. Polarizing unit, polarizing illumination device using same polarizing unit and projection display device using same polarizing illumination device
EP1363460A2 (fr) * 2002-05-10 2003-11-19 Seiko Epson Corporation Système d'éclairage et projecteur
WO2007138501A2 (fr) * 2006-05-24 2007-12-06 Koninklijke Philips Electronics N.V. Moteur de projection miniature

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5898521A (en) * 1995-11-17 1999-04-27 Matsushita Electric Industrial Co., Ltd. LCD Projector
KR20020039798A (ko) * 2000-11-22 2002-05-30 김순택 3개의 컬러 휠을 구비한 프로젝션 시스템
US20030086066A1 (en) * 2001-11-02 2003-05-08 Nec Viewtechnology, Ltd. Polarizing unit, polarizing illumination device using same polarizing unit and projection display device using same polarizing illumination device
EP1363460A2 (fr) * 2002-05-10 2003-11-19 Seiko Epson Corporation Système d'éclairage et projecteur
WO2007138501A2 (fr) * 2006-05-24 2007-12-06 Koninklijke Philips Electronics N.V. Moteur de projection miniature

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102004321A (zh) * 2010-08-27 2011-04-06 浙江金成科技发展有限公司 具有单个偏振转换器的led液晶投影机的光学结构
CN103221735A (zh) * 2010-11-17 2013-07-24 Nec显示器解决方案株式会社 光源设备、照明设备和投影型显示设备
CN103221735B (zh) * 2010-11-17 2015-05-13 Nec显示器解决方案株式会社 光源设备、照明设备和投影型显示设备
US9046750B2 (en) 2010-11-17 2015-06-02 Nec Display Solutions, Ltd. Projector light source apparatus having collimator disposed between excitation light source and phosphor element
CN111602084A (zh) * 2018-01-18 2020-08-28 苹果公司 空间复用方案
CN111602084B (zh) * 2018-01-18 2022-02-11 苹果公司 空间复用方案
US11493606B1 (en) 2018-09-12 2022-11-08 Apple Inc. Multi-beam scanning system

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