EP0839333A1 - Procede et dispositif pour transmettre un faisceau lumineux de faible divergence injecte dans un guide de lumiere et destine a eclairer les points d'image d'une image video - Google Patents

Procede et dispositif pour transmettre un faisceau lumineux de faible divergence injecte dans un guide de lumiere et destine a eclairer les points d'image d'une image video

Info

Publication number
EP0839333A1
EP0839333A1 EP97920678A EP97920678A EP0839333A1 EP 0839333 A1 EP0839333 A1 EP 0839333A1 EP 97920678 A EP97920678 A EP 97920678A EP 97920678 A EP97920678 A EP 97920678A EP 0839333 A1 EP0839333 A1 EP 0839333A1
Authority
EP
European Patent Office
Prior art keywords
light
light guide
optical system
core
diameter
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP97920678A
Other languages
German (de)
English (en)
Inventor
Christhard Deter
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
LDT Laser Display Technology GmbH
Original Assignee
LDT GmbH and Co Laser Display Technologie KG
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 LDT GmbH and Co Laser Display Technologie KG filed Critical LDT GmbH and Co Laser Display Technologie KG
Publication of EP0839333A1 publication Critical patent/EP0839333A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/12—Picture reproducers
    • H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
    • H04N9/3129—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM] scanning a light beam on the display screen
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/32—Optical coupling means having lens focusing means positioned between opposed fibre ends
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/74—Projection arrangements for image reproduction, e.g. using eidophor

Definitions

  • Method and device for transmitting a light beam of low divergence which is provided for illuminating pixels of a video image and is coupled into an optical fiber
  • the invention relates to a method for transmitting a light beam provided for illuminating pixels of a video image with the type of its
  • the invention further relates to a video system for carrying out the method with a light source for emitting a light bundle for illuminating pixels of a video image, with a light guide for light transmission, into which a light bundle to be transmitted is coupled with a divergence and a predetermined beam diameter predetermined by the light source, and with an optical system for bundling the transmitted light bundle.
  • Video systems in which pixels are illuminated with the aid of light beams are known, for example, from DE 43 24 848 C1.
  • at least one light beam is deflected by a screen according to a video standard, similar to how it is used for television viewing by means of a screen
  • Electron beam with the deflection coils provided for scanning is known.
  • the light beam is intensity-modulated, analogously to the electron beam mentioned, in order to generate a gray value or color corresponding to the image content for the individual pixels shown on the screen.
  • Laser beams are usually used as the light bundle, since these are very parallel and also in large quantities
  • DE 43 24 848 C1 proposes to spatially separate the device for scanning the laser beams in the direction of light propagation behind the laser modulation device. This is for maintenance and / or for a particularly affordable one
  • Optical fibers in particular are optical fibers known in which the light is guided in a coated core. Unwanted escape of light from the core is avoided by total reflection between the core and the jacket.
  • a low divergence is a prerequisite for the laser light spot, which essentially determines the pixel size, on the screen to be so small that it corresponds to the required line resolution.
  • the divergence is greatly increased when using an optical fiber.
  • Raster device always receives a sharp image.
  • This advantageous property of an almost parallel light beam for illuminating pixels makes it possible, for example, to display an image on objects of any shape, which is not possible with other projectors.
  • the transmission within an optical fiber also has a decisive influence on the mode structure of the laser beam, because when using multimode optical fibers, the single-mode structure of the laser is broken down into a large number of modes. Possibly one could parallelize a single mode of the resulting modes according to the teaching of DE 43 24 848 C1, but the others are then widened, so that there is no resolution suitable for high-resolution video images for the entire light bundle emerging from the optical fiber.
  • a collecting lens is arranged on the light exit surface of the optical waveguide according to DE 43 24 848 C1, the focal point of which coincides with the center of the light exit surface. This theoretically achieves that the point of the light exit surface, which contains the optical axis of the converging lens, is imaged in the infinite.
  • the light exit surface of the optical waveguide is finite
  • Parallelism cannot be achieved for the propagation condition of the laser light, which emerges over the entire cross-sectional area of the optical waveguide, for example also in the vicinity of the cladding of an optical fiber.
  • the imaging of laser beams emerging even parallel to the optical axis by means of the lens can also greatly reduce the achievable resolution owing to the light beam which is expanded by this lens and strikes the screen.
  • the object is achieved by a method in which the optical system is used to set a divergence angle for the light bundle leaving the light guide in proportion to the divergence angle given by the type of production, the
  • a generic video system according to the invention is characterized in that the optical system is arranged at a location relative to the light guide and has a defined focal length at which and at which a divergence angle for the end leaving the light guide
  • the light beam is proportional to the divergence angle specified by the light source, the proportionality factor being the ratio of the beam diameter specified by the light source to the beam diameter of the light beam emanating from the optical system.
  • the light beam emanating from the light guide is not parallelized.
  • a divergence angle is not only permitted, but even required. This is also in contrast to the view that with a parallel light beam at very great distances, as in the aforementioned Video system is common, of course a small focus point is expected.
  • the invention is based on the knowledge that even without a light guide, it would only be possible to achieve a limited pixel size, which is determined on the basis of widening in the beam generation given divergence of the light beam and which cannot be improved.
  • phase space occupation of the photons in the pulse space then remains the same, regardless of whether the spatial portion of the phase space is changed by the light guide.
  • Optical waveguides for example light guide rods, or cylinders with a sealed one
  • the optical system is arranged with respect to the axis of the light guide so that the optical axis of the optical system extends perpendicular to the core surface of the light guide on the output side and extends centrally from the core surface and the optical system has a main plane on its side, the position of which extending through the intersection of the optical axis with a starting from the core circumference, extending at the divergence angle of the light beam coupled out of the light guide to the optical axis
  • This arrangement is particularly favorable since it ensures not only that the light bundle emanating from the center of the core has the divergence required according to the invention, but the light rays emanating from the entire surface of the core of the light guide through the optical system in corresponding light beams with that required according to the invention Divergence to be transferred.
  • the optical system as a single lens, in which the main plane indicates the lens position. Then that is namely the partial beam of the light beam that is coupled out of the light guide at the divergence angle and that extends from the circumference of the core
  • the light guide then has a core diameter dk and an aperture A assigned to it for the expansion of light, the product of dk and A of which is equal to the product of the divergence angle, measured in radians, with the diameter of the coupled light bundle of predetermined divergence.
  • this selection of the light guide according to the further development also allows the entire intensity of the light bundle incident on the input side to be coupled into the light guide.
  • the complete coupling of the light bundle into the light guide will be considered in more detail later.
  • Optical fiber is transmitted, instead of the actual diameter of the coupled light bundle, a corresponding equivalent diameter, such as the diameter of the diaphragm or the core of the light guide, must be used in the relationship mentioned for the selection of the light guide.
  • an optimal transmission of the light bundle essentially depends on the aperture of the light guide.
  • the invention can best be implemented when the aperture of the light guide is between 0.05 and 0.15 and the core diameter of the light guide is in the range from 10 ⁇ m to 30 ⁇ m.
  • the aperture has a value of 0.1, the light guide having a core diameter of 15 ⁇ m.
  • the distance of the optical system from the light guide cannot be chosen arbitrarily, which affects the focal length, especially since the focal point should be close to the core. A very large distance from the exit of the light guide would result in very large lenses, a very small distance increases the effort for the adjustment.
  • the optical system of positive refractive power has a magnitude of the focal length in the range from 15 mm to 25 mm and in particular a value of 20 mm.
  • Coupling the light source generated laser light bundles into the light guide can be achieved in that a further optical system is provided for coupling the light bundle into the light guide.
  • the further optical system focuses the light bundle of predetermined divergence to be coupled centrally on the core of the light guide, the diffraction-limited focus diameter of the further optical system generated on the core being less than or equal to 2 / 3 of
  • Core diameter is. Furthermore, there is a particularly favorable coupling in accordance with a preferred development of the invention if the optical axis of the further optical system at the input of the light guide extends perpendicular to the core diameter and concentrically to the core. Because of this development, partial loss due to diffraction or direct reflection between the core and the jacket from the light guide is substantially avoided.
  • Fig. 1 is a schematic representation of an embodiment of the
  • Fig. 2 is a schematic representation in section to explain the
  • Geometry of an embodiment with an optical system shows a geometric arrangement of a further optical system for coupling into an optical fiber;
  • Fig. 4 shows an arrangement for a video projection system in which a
  • Optical fiber is used in combination with an optical system.
  • Fig. 1 the incident light beam is indicated with a perspective arrow 1 and the emerging light beam with another arrow 2 also shown.
  • the shafts of arrows 1 and 2 are frustoconical, which indicates the divergence of the incident and the emerging light beam.
  • the shafts of arrows 1 and 2 have the same inclination, which makes it clear that the outgoing light beam (arrow 2) has the same divergence angle as the incoming one
  • the incoming and outgoing light bundle should have the same diameter.
  • the beam product of the divergence angle and beam diameter is the same as that of the incident light beam in the case of the emerging light beam.
  • the following considerations always refer to the same beam diameter of the incoming and outgoing light beam. If the beam diameter changes due to optical systems located in the beam path, the divergences mentioned below must always be adapted to the same beam products.
  • optical system 4 which is designed in a suitable manner and is arranged with respect to the output of an optical fiber 6.
  • a light-guiding core 8 is also indicated in the optical fiber 6.
  • Arrows 9 and 10 illustrate the maximum
  • optical fiber 6 which runs concentrically to the core 8 and perpendicularly from the core exit surface
  • Optical fiber 6 is shown as a dash-dotted line, which coincides on the output side with the optical axis of the optical system 4 and on the input side with the optical axis of the incident light bundle denoted by the arrow 1.
  • optical fiber 6 shown in broken lines only illustrates the input and output details of the light transmission arrangement. In practice, the ends of the light guide 6 will, of course, be twisted and / or displaced relative to one another.
  • FIG. 1 illustrates by the representation of arrow 1 that a light bundle with low divergence is coupled into the optical fiber 6. Due to reflections between
  • the core and cladding of the optical fiber 6, the transmitted light bundle is widened, as indicated by the arrows 9 and 10.
  • the optical system 4 in particular also with respect to its distance from the optical fiber 6, is designed such that the light beam indicated by the arrow 2 receives the same divergence as the coupled light beam shown schematically by the arrow 1.
  • the equality of the divergences are shown schematically in FIG. 1 via the same frustoconical design
  • the coupled light bundle can be directed directly onto the core 8 of the optical fiber 6.
  • the diameter of laser beams that can be used in video systems is usually much larger than the cores of
  • An exemplary embodiment of this is shown in FIG. 3.
  • the optical system 4 is shown here as a single lens for simplicity. In the case of special requirements, for example for color correction, an optical system consisting of several lenses, an achromatic lens, will be used for color correction. Then the plane designated as H in FIG. 2 of the optical system 4 represented as a lens in FIG. 2 is the main plane on the thing side and at the same time on the picture side.
  • the divergence of the emerging beam is indicated by the divergence angle ⁇ .
  • the divergence angle ⁇ is the angle between the optical axis and the straight line from the edge point of the fiber core through the intersection of H with the optical axis. Via the design of the optical system 4, this is equal to the divergence angle ⁇ of the injected beam of low divergence shown in FIG. 3
  • the optical system 4 has now been designed with respect to its focal length such that the light bundle emerging from the optical fiber 6 at an angle A through the optical system 4 into the emerging, limited by arrows
  • the angle A here designates the aperture, which occurs in the exemplary embodiment as an angle because the optical fiber had an aperture there with small values between 0.05 and 0.15 and in particular 0.1, which is why the sine of the angle, which usually describes the aperture , can be set approximately equal to the angle expressed in radians.
  • Beam diameter and diameter can be understood.
  • the optical fiber 6 was selected so that its product of aperture and core diameter is equal to the divergence ⁇ of the coupled beam 14 multiplied by the
  • Diameter d of the beam coupled into the optical fiber (FIG. 3). Since the entire light bundle according to FIG. 3 is coupled into the optical fiber 6 via a further optical system 20, the condition of the constant beam product also applies during the coupling. It follows from this that in this embodiment, with the coupling of the light beam 14 via the further optical system 20
  • Video projection used, starting from the optical fiber 6 light bundle 15 has practically the same divergence as the beam emerging from the source. This advantageous property also results when a multimode fiber is used, since the preservation of the beam product is valid regardless of the mode structure.
  • the above-mentioned aperture values of 0.05 to 0.15 relate to an optical fiber diameter of 10 ⁇ m to 30 ⁇ m and in particular 15 ⁇ m.
  • a further property of the optical system 4 results from FIG. 2. Its main axis H is located at a location at which a straight line 18 running from the circumference of the core 8 at an angle ⁇ to the optical axis 12 is the optical axis 12 cuts. The light beam emerging along the straight line 18 of the light bundle emerging from the optical fiber 6 then goes with the
  • the optical system 4 thus forms at least approximately all the light rays emanating from the core 8 into the emitting light bundle 15.
  • the entire surface area of the core 8 is thus uniformly transformed via the optical system 4.
  • the light bundle 15 therefore has essentially the same optical properties with regard to parallelism and diameter as the incoming light bundle 14.
  • optical systems 4 and 20 simple lenses with a focal length of 20 mm were used for the optical systems 4 and 20.
  • Optical systems 4 and 20 with focal lengths between 15 and 25 mm are also particularly suitable.
  • a first assembly 30 there are three lasers 32, 33, 34, the outgoing light beams of which are intensity-modulated via modulators 35, 36 and 37.
  • the light beams emanating from the modulators 35, 36, 37 are combined via a mirror system 40 to form a single light beam 14, which is coupled into the optical fiber 6 via an optical system 20.
  • the previously described optical system 4 is used for decoupling, from which the outgoing Beams of light 15 are thrown onto a raster device consisting of a polygon mirror 42 and a swivel mirror 44, deflected there and made visible as a video image to a viewer sitting in the direction of the arrow via a transformation optics 46 on a screen 50.
  • a multimode fiber is used to transmit three light beams with different wavelengths.
  • the principle shown in FIGS. 1 to 3 can also be used for single-mode fibers, with a single optical fiber 6 with optical systems 4 and 20 being assigned to each laser beam of different wavelengths in a color video system.

Landscapes

  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • General Physics & Mathematics (AREA)
  • Optical Couplings Of Light Guides (AREA)

Abstract

L'invention concerne un procédé permettant de transmettre un faisceau lumineux injecté dans un guide de lumière et destiné à éclairer les points d'image d'une image vidéo et présentant un angle de divergence et un diamètre déterminés par son mode de production. Ce faisceau lumineux est désaccouplé par un système optique servant à grouper un faisceau lumineux (15) transmis qui sort du guide de lumière (6). Il est prévu d'ajuster à l'aide du système optique (4), un angle de divergence pour le faisceau lumineux (15) qui sort du guide de lumière (6), de manière proportionnelle à l'angle de divergence déterminé par le mode de production du faisceau lumineux. Le facteur de proportionnalité constitue le rapport du diamètre de rayonnement donné du faisceau avant injection dans le guide de lumière (6) au diamètre de rayonnement du faisceau lumineux sortant du système optique. Un système vidéo approprié pour mettre ledit procédé en oeuvre présente un système optique (4) dimensionné en conséquence.
EP97920678A 1996-04-26 1997-04-14 Procede et dispositif pour transmettre un faisceau lumineux de faible divergence injecte dans un guide de lumiere et destine a eclairer les points d'image d'une image video Withdrawn EP0839333A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19616843A DE19616843A1 (de) 1996-04-26 1996-04-26 Verfahren und Vorrichtung zum Übertragen eines zum Ausleuchten von Bildpunkten eines Videobildes vorgesehenen, in einen Lichtleiter eingekoppelten Lichtbündels geringer Divergenz
DE19616843 1996-04-26
PCT/EP1997/001863 WO1997041473A1 (fr) 1996-04-26 1997-04-14 Procede et dispositif pour transmettre un faisceau lumineux de faible divergence injecte dans un guide de lumiere et destine a eclairer les points d'image d'une image video

Publications (1)

Publication Number Publication Date
EP0839333A1 true EP0839333A1 (fr) 1998-05-06

Family

ID=7792602

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97920678A Withdrawn EP0839333A1 (fr) 1996-04-26 1997-04-14 Procede et dispositif pour transmettre un faisceau lumineux de faible divergence injecte dans un guide de lumiere et destine a eclairer les points d'image d'une image video

Country Status (5)

Country Link
US (1) US5892556A (fr)
EP (1) EP0839333A1 (fr)
JP (1) JPH10510638A (fr)
DE (1) DE19616843A1 (fr)
WO (1) WO1997041473A1 (fr)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19726860C1 (de) * 1997-06-24 1999-01-28 Ldt Gmbh & Co Verfahren und Vorrichtung zur Darstellung eines Videobildes sowie ein Herstellungsverfahren für die Vorrichtung
DE19805111A1 (de) * 1998-02-09 1999-08-19 Ldt Gmbh & Co Vorrichtung zum Ablenken, ihre Verwendung sowie ein Videosystem
US7343343B1 (en) 1999-09-01 2008-03-11 Sony Corporation Electronic goods-purchasing method and commercial-transaction apparatus therefor
JP2003295112A (ja) * 2002-04-05 2003-10-15 Canon Inc 走査型画像表示光学系、走査型画像表示装置および画像表示システム
US7088353B2 (en) * 2002-07-10 2006-08-08 Fuji Photo Film Co., Ltd. Display device
DE10240057B4 (de) * 2002-08-30 2007-10-25 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Optischer Multiplexer und Demultiplexer für optische Fasern mit großer numerischer Apertur
KR100634539B1 (ko) * 2005-02-07 2006-10-13 삼성전자주식회사 주사 광학 이미징 시스템
CN101690244A (zh) * 2007-06-27 2010-03-31 皇家飞利浦电子股份有限公司 激光扫描投影设备

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2154017B (en) * 1984-02-03 1987-09-30 Gen Electric Laser material processing through a fiber optic
US4823402A (en) * 1986-04-21 1989-04-18 Trw Inc. Agile optical beam steering system
US4818049A (en) * 1987-06-10 1989-04-04 Allied-Signal Inc. Method and apparatus for efficiently conveying light over a distance and effecting controlled illumination by projection thereof
US4868361A (en) * 1988-04-01 1989-09-19 General Electric Company Coupling device for high power laser beam transmitting optical fibers
DE4105719A1 (de) * 1991-02-23 1992-09-03 Aesculap Ag Vorrichtung zur uebertragung medizinisch wirksamer laserstrahlung sowie verfahren zur uebertragung von laserstrahlung
DE4324848C1 (de) * 1993-07-23 1995-03-30 Schneider Rundfunkwerke Ag Videoprojektionssystem

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9741473A1 *

Also Published As

Publication number Publication date
JPH10510638A (ja) 1998-10-13
WO1997041473A1 (fr) 1997-11-06
DE19616843A1 (de) 1997-11-06
US5892556A (en) 1999-04-06

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