WO2006129151A1 - Systeme d'eclairage de videoprojecteur comprenant une pluralite de lampes - Google Patents

Systeme d'eclairage de videoprojecteur comprenant une pluralite de lampes Download PDF

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Publication number
WO2006129151A1
WO2006129151A1 PCT/IB2006/001325 IB2006001325W WO2006129151A1 WO 2006129151 A1 WO2006129151 A1 WO 2006129151A1 IB 2006001325 W IB2006001325 W IB 2006001325W WO 2006129151 A1 WO2006129151 A1 WO 2006129151A1
Authority
WO
WIPO (PCT)
Prior art keywords
illumination
light beam
lamps
videoprojectoraccording
integrating bar
Prior art date
Application number
PCT/IB2006/001325
Other languages
English (en)
Inventor
Giorgio Barazza
Original Assignee
Sim2 Multimedia S.P.A.
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 Sim2 Multimedia S.P.A. filed Critical Sim2 Multimedia S.P.A.
Publication of WO2006129151A1 publication Critical patent/WO2006129151A1/fr

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
    • G02B27/12—Beam splitting or combining systems operating by refraction only
    • G02B27/123—The splitting element being a lens or a system of lenses, including arrays and surfaces with refractive 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
    • G02B27/0972—Prisms
    • 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
    • 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
    • H04N9/3152—Modulator illumination systems for shaping the light beam

Definitions

  • the present invention relates to a system of illumination for videoprojector according to the preamble of claim 1.
  • small electromechanical devices such as, for instance, DMD (Digital Micromirror Device), LCD (Liquid Cristal Display) and LCoS (Liquid Cristal on Silicon) devices are widely used for manufacturing videoprojectors, because they allow to obtain small, light apparatus producing a high-quality image.
  • DMD Digital Micromirror Device
  • LCD Liquid Cristal Display
  • LCoS Liquid Cristal on Silicon
  • a DMD device or panel consists of a set of small square mirrors typically made of aluminium and having a side approximately 13 ⁇ m long, each of which represents an element of the image to be projected, i.e. a pixel.
  • the mirrors can rotate about a diagonal at a certain angle, e.g. ⁇ 12 degrees, and the rotation in either direction is produced by two electrodes located under the mirror, on opposite sides with respect to the axis of rotation.
  • the light strikes the mirror at an angle of approximately 26 degrees relative to the perpendicular of the plane of the mirror, when the latter is "at rest", i.e. when it is not attracted by either electrode.
  • a projection lens which focuses the image onto the screen.
  • a pixel consists of a layer of liquid crystals enclosed between two plates, or electrodes, which are arranged parallel to each other; when a light beam is sent to a plate, the quantity of light going through the liquid crystal layer can be controlled by means of the voltage applied to the electrodes and by using suitable polarizers.
  • transmission-type devices which generally consist of LCD devices
  • both electrodes are transparent, therefore the light beam enters one plate, and exits from the other plate, and is then sent to the screen.
  • reflection-type devices which generally consist of LCoS devices
  • one plate is transparent and the other one is reflective, so that the light beam goes through the transparent plate, is reflected by the reflective plate, goes through ' the transparent plate again and is finally sent to the screen.
  • the set of pixels represents the active surface of the panel, on which the image to be projected onto the screen is formed.
  • each system of illumination for videoprojector may use one or more devices for the formation of the image, in particular DMD, LCD or LCoS devices; preferably, each system of illumination employs devices of the same type.
  • DMD digital versatile disk
  • LCD liquid crystal display
  • LCoS devices preferably, each system of illumination employs devices of the same type.
  • the choice of the illuminating device used is of great importance.
  • systems of illumination for videoprojector use systems of illumination consisting of arc lamps, which provide a high luminous intensity.
  • Fig. Ia shows a diagram of a system of illumination for videoprojector according to the prior art.
  • a lamp 1 emits a parallel light beam having a substantially circular section as said lamp 1 is provided with a parabolic shaped reflector.
  • An aspheric condenser sends said light beam to an integrating bar 3, consisting of a parallelepiped made of optical-glass having an inlet face 4 and an outlet face 5,which allows to uniform the light beam exiting from the aspheric condenser 2.
  • said aspheric condenser 2 sends a conical light beam, represented by the triangle f-f-f ' in the horizontal projection of Fig. Ia, to the integrating bar 3; said conical light beam is intercepted by the inlet face 4, so as to form a circle having a diameter d on the surface of said inlet face 4.
  • Fig. Ib shows the inlet face 4 of the integrating bar 3 and the circle having a diameter d which indicates the area illuminated by the conical light beam striking said inlet face.
  • the angular aperture of the conical light beam i.e. the angle in the vertex f of the cone, is equal to an angle 2 ⁇ in the representation of Fig. Ia.
  • the light beam exiting from the integrating bar 3 is collected by a system of converging lenses 6, known as "relay lenses”, and is then sent to means, e.g. a prism system not shown in Fig. Ia, adapted to break up the light beam, according to known techniques, into the three primary monochromatic components it is composed of, in particular the red, green and blue monochromatic components.
  • a system of converging lenses 6, known as "relay lenses” e.g. a prism system not shown in Fig. Ia, adapted to break up the light beam, according to known techniques, into the three primary monochromatic components it is composed of, in particular the red, green and blue monochromatic components.
  • Said primary monochromatic components are then directed to the active surface of several devices for the formation of the image, e.g. three DMDs (Digital Micromirror Devices), not shown in the drawings for simplicity's sake.
  • DMDs Digital Micromirror Devices
  • the angular aperture of the conical light beam entering said integrating bar 3, and thus the angle 2 ⁇ , is selected so as to use in the appropriate conditions the various components of the system of illumination which convey the light beam to the devices for the formation of the image, thereby maximizing the light transfer.
  • a higher lamp power causes the entire system of illumination to become hotter and therefore more difficult to cool, thus requiring bulky cooling solutions.
  • An increase in the brightness of a system of illumination for videoprojector may also be obtained by using the known arrangement shown in Fig.
  • both lamps 1, 1' emit a parallel light beam having a substantially circular section, since said lamps 1, 1' are provided with a parabolic shaped reflector; the use of lamps provided with a parabolic shaped reflector requires the use of collimating means, which allow to converge the parallel light beam generated by the lamps.
  • each of said lamps 1, 1' is associated with a collimating means, in particular an aspheric condenser 2, 2', which allows to converge the light beam into the integrating bar 3.
  • Each lamp 1, 1' generates a light beam having a magnitude equal to 2 ⁇ ; the angle of incidence of the light beam when it enters the integrating bar 3 is equal to the sum of the angles of the light beams generated by both lamps 1, 1', and therefore its magnitude is equal to 4 ⁇ .
  • the overall angular aperture 4 ⁇ of the light beam exiting from the integrating bar 3 turns out to be twice as the angular aperture of the light beam exiting from the integrating bar 3 produced by a single lamp.
  • Fig. 2 clearly shows that, since the angular aperture 4 ⁇ of the light beam exiting from the integrating bar 3 is wider, in order to intercept a portion as big as possible of the light beam it is necessary to increase the dimensions of the system of converging lenses 6 and of the other means, eg. prisms not shown in the drawings, which allow to convey the light beam to the devices for the formation of the image, e.g. DMD devices. This inevitably leads to increased costs of the components used in the system of illumination.
  • the components normally used in the systems of illumination known in the art require the use of light beams having a limited angular aperture. Consequently, if the system of illumination employs a light beam exiting from the integrating bar 3 with a very wide angular aperture, at least a portion of said light beam will not be used. This will lead to a lower brightness level of the whole system of illumination; furthermore, the unused portion of the light beam will scatter in the system of illumination, thus causing a considerable drop in contrast. It follows that the expected brightness increase due to a doubled light source will not be reached in full.
  • the object of the present invention is to provide a system of illumination using a plurality of lamps which, by overcoming the above drawbacks, allows to manufacture high-brightness and high-contrast videoprojectors without jeopardizing the reliability of the videoprojector itself and at the same time avoiding any increase in the costs of the components used for its production.
  • Ia 3 Ib, Ic show a first system of illumination for videoprojector according to the prior art
  • FIG. 2 shows a second system of illumination for videoprojector according to the prior art
  • FIG. 3a, 3b and 3c show a first embodiment of a system of illumination for videoprojector according to the invention
  • FIG. 4 shows a second embodiment of a system of illumination for videoprojector according to the invention
  • FIG. 5 shows a third embodiment of a system of illumination for videoprojector according to the invention.
  • FIG. 3a shows a first embodiment of a system of illumination for videoprojector according to the invention; said system of illumination comprises a plurality of lamps.
  • Said plurality of lamps comprises two lamps 1, 1' which, for simplicity's sake, are supposed to be identical; it is clear that the following considerations may be easily extended to a system of illumination comprising more than two lamps, even being different from one another.
  • Each of said lamps 1, 1' emits a parallel light beam having a substantially circular section, in that said lamps 1, 1 ' are provided with a parabolic shaped reflector.
  • lamps 1, 1' provided with a parabolic shaped reflector requires that each of said lamps 1, I' be associated with a collimating means, in particular an aspheric condenser 2, 2', which allows to converge the parallel light beam generated by the lamps 1, 1'.
  • the lamps 1, 1' are associated with two transparent deflecting prisms, being in particular of the "wedge" type and preferably small in size, designated with reference numbers 8 and 8' in Fig. 3a; in particular, in the representation of Fig. 3a said transparent deflecting prisms 8, 8' are positioned between the aspheric condensers 2 and 2', respectively, and an integrating bar 3.
  • the transparent deflecting prism 8 deflects the light beams coming from the lamp 1 and from the respective aspheric condenser 2, so that a first external ray 9 undergoes such a deflection as to generate a light ray 9', which strikes an inlet face 4 of the integrating bar 3 at an angle ⁇ , i.e. with an angular aperture being equal to half the angular aperture of the light beam entering said integrating bar 3, shown in Fig. Ia 5 when a single lamp 1 is used which lamp is adapted to generate a light beam having an angular aperture equal to 2 ⁇ .
  • a second external ray 10 of the light beam generated by the lamp 1 is deflected by the transparent deflecting prism 8 so as to undergo a minimum deflection.
  • the transparent deflecting prism 8' deflects the light beam coming from the lamp I 1 and from the respective aspheric condenser 2' so that a first external ray 11 undergoes such a deflection as to generate a light ray 11 ' striking said inlet face 4 of the integrating bar 3 at the same aforementioned angle ⁇ , whereas a second external ray 12 undergoes a minimum deflection.
  • Fig. 3b shows the inlet face 4 of the integrating bar 3, on which of course two illuminated areas appear, each having a diameter d, instead of a single area as in the representation of Fig. Ib.
  • Fig. 3c shows an outlet face 5 of the integrating bar 3, which face, due to the multiple reflections taking place within the integrating bar 3, is evenly illuminated.
  • the conical light beam exiting from the integrating bar 3 has an angular aperture being equal to that of the conical light beam entering the integrating bar 3; it follows that, also with reference to the representation of Fig. 3a, the angle 2 ⁇ turns out to be equal to the angle 2 ⁇ .
  • the light beam exiting from the integrating bar 3 is collected by a system of converging lenses 6, known in particular as "relay lenses", and is then sent to decompose means, e.g.
  • a prism system not shown in Fig. 3a, adapted to divide the light beam, according to known techniques, into the three red, green and blue primary monochromatic components.
  • Said primary monochromatic components are further directed toward the active surface of devices for the formation of the image, e.g. three DMDs (Digital Micromirror Devices), not shown in the illustrations.
  • DMDs Digital Micromirror Devices
  • the devices for the formation of the image which for instance may comprise three DMD, LCD or LCoS devices, one may use the same components, in particular "relay lenses” 6 and prisms not shown in the drawings, as those used in systems of illumination for videoprojector using just one lamp 1, thus with no increase in the costs of the components used in the system of illumination.
  • the use of the transparent deflecting prisms 8, 8' also allows to obtain a light beam exiting from the integrating bar 3 having a narrow angular aperture, so as to allow for a full utilization of the whole light beam in the system of illumination for videoprojector according to the present invention, thereby preventing any brightness and contrast reduction phenomena from arising in the entire system of illumination. Furthermore, in the system of illumination according to the present invention it is possible to turn on the lamps 1, 1' at a power being lower than the nominal power, thereby obtaining a longer life of said lamps 1, 1'.
  • the light beam produced by the lamps 1, 1' is divided, according to a known technique, into the three red, green and blue primary monochromatic components; these are then sent to a plurality of devices for the formation of the image to be projected, e.g. to three different DMD devices.
  • said system of illumination may advantageously comprise a rotating wheel, also known as colour wheel, designated 13 in Fig. 4 and positioned between the transparent deflecting prisms 8, 8' and the inlet face 4 of the integrating bar 3.
  • Fig. 5 shows a further embodiment of the system of illumination for videoprojector according to the present invention, which comprises a plurality of lamps 14, 14'. Said lamps 14, 14' are provided with an elliptic shaped reflector adapted to generate a conical light beam; as a result, this solution does not require the use of collimating means associated with each of said lamps 14, 14' in order to converge the light beam.
  • the transparent deflecting prisms 8, 8' are positioned between the lamps 14, 14' and the inlet face 4 of the integrating bar 3.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Projection Apparatus (AREA)
  • Non-Portable Lighting Devices Or Systems Thereof (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)

Abstract

L'invention concerne un système d'éclairage pour vidéoprojecteur, qui comprend: une pluralité de lampes (1, 1', 14, 14') permettant de produire un faisceau lumineux, une barre d'intégration (3), en particulier une barre comprenant une face d'entrée (4), est une face de sortie (5), permettant d'uniformiser le faisceau lumineux produit par ladite pluralité de lampes (1, 1', 14, 14'), un système de lentilles convergentes (6), permettant de collecter le faisceau lumineux sortant de ladite barre d'intégration (3). Chaque lampe (1, 1', 14, 14') composant cette pluralité est associée à un prisme (8, 8') de renvoi transparent, qui permet de réduire l'ouverture angulaire du faisceau lumineux produit par ladite pluralité de lampes (1, 1', 14, 14').
PCT/IB2006/001325 2005-06-01 2006-05-22 Systeme d'eclairage de videoprojecteur comprenant une pluralite de lampes WO2006129151A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT000379A ITTO20050379A1 (it) 2005-06-01 2005-06-01 Sistema di illuminamento per videoproiettore che utilizza una pluralita' di lampade
ITTO2005A000379 2005-06-01

Publications (1)

Publication Number Publication Date
WO2006129151A1 true WO2006129151A1 (fr) 2006-12-07

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Application Number Title Priority Date Filing Date
PCT/IB2006/001325 WO2006129151A1 (fr) 2005-06-01 2006-05-22 Systeme d'eclairage de videoprojecteur comprenant une pluralite de lampes

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IT (1) ITTO20050379A1 (fr)
TW (1) TW200702888A (fr)
WO (1) WO2006129151A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102645275A (zh) * 2012-05-04 2012-08-22 中国计量科学研究院 一种产生对比度和色差观察目标的装置
CN102657510A (zh) * 2012-05-04 2012-09-12 中国计量科学研究院 一种产生照度和颜色观察目标的装置
CN103308172A (zh) * 2012-12-26 2013-09-18 中国计量科学研究院 一种测量视觉阈值的装置与方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5619284A (en) * 1995-01-17 1997-04-08 Philips Electronics North America Corporation Beam combiner for LCD projector utilizing a penta-prism
JPH11119149A (ja) * 1997-10-17 1999-04-30 Matsushita Electric Ind Co Ltd 液晶プロジェクション装置
WO2004107018A1 (fr) * 2003-06-02 2004-12-09 Koninklijke Philips Electronics N.V. Systeme d'eclairage a diodes electroluminescentes
US20050046981A1 (en) * 2003-08-25 2005-03-03 Nec Viewtechnology, Inc. Color projection type display apparatus reusing incident light

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5619284A (en) * 1995-01-17 1997-04-08 Philips Electronics North America Corporation Beam combiner for LCD projector utilizing a penta-prism
JPH11119149A (ja) * 1997-10-17 1999-04-30 Matsushita Electric Ind Co Ltd 液晶プロジェクション装置
WO2004107018A1 (fr) * 2003-06-02 2004-12-09 Koninklijke Philips Electronics N.V. Systeme d'eclairage a diodes electroluminescentes
US20050046981A1 (en) * 2003-08-25 2005-03-03 Nec Viewtechnology, Inc. Color projection type display apparatus reusing incident light

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 1999, no. 09 30 July 1999 (1999-07-30) *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102645275A (zh) * 2012-05-04 2012-08-22 中国计量科学研究院 一种产生对比度和色差观察目标的装置
CN102657510A (zh) * 2012-05-04 2012-09-12 中国计量科学研究院 一种产生照度和颜色观察目标的装置
CN103308172A (zh) * 2012-12-26 2013-09-18 中国计量科学研究院 一种测量视觉阈值的装置与方法

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Publication number Publication date
TW200702888A (en) 2007-01-16
ITTO20050379A1 (it) 2006-12-02

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