WO2005121641A1 - Systeme d'eclairage - Google Patents

Systeme d'eclairage Download PDF

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Publication number
WO2005121641A1
WO2005121641A1 PCT/IB2005/051803 IB2005051803W WO2005121641A1 WO 2005121641 A1 WO2005121641 A1 WO 2005121641A1 IB 2005051803 W IB2005051803 W IB 2005051803W WO 2005121641 A1 WO2005121641 A1 WO 2005121641A1
Authority
WO
WIPO (PCT)
Prior art keywords
light
transparent element
illumination system
dispersing structure
liquid crystal
Prior art date
Application number
PCT/IB2005/051803
Other languages
English (en)
Inventor
Christoph G. A. Hoelen
Johannes P. M. Ansems
Lingli Wang
Rifat A. M. Hikmet
Original Assignee
Koninklijke Philips Electronics N.V.
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 Koninklijke Philips Electronics N.V. filed Critical Koninklijke Philips Electronics N.V.
Publication of WO2005121641A1 publication Critical patent/WO2005121641A1/fr

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V14/00—Controlling the distribution of the light emitted by adjustment of elements
    • F21V14/003—Controlling the distribution of the light emitted by adjustment of elements by interposition of elements with electrically controlled variable light transmissivity, e.g. liquid crystal elements or electrochromic devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V5/00—Refractors for light sources
    • F21V5/002—Refractors for light sources using microoptical elements for redirecting or diffusing light
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L25/00—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof
    • H01L25/16—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof the devices being of types provided for in two or more different main groups of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. forming hybrid circuits
    • H01L25/167—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof the devices being of types provided for in two or more different main groups of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. forming hybrid circuits comprising optoelectronic devices, e.g. LED, photodiodes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2113/00—Combination of light sources
    • F21Y2113/10—Combination of light sources of different colours
    • F21Y2113/13—Combination of light sources of different colours comprising an assembly of point-like light sources
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2113/00—Combination of light sources
    • F21Y2113/10—Combination of light sources of different colours
    • F21Y2113/13—Combination of light sources of different colours comprising an assembly of point-like light sources
    • F21Y2113/17—Combination of light sources of different colours comprising an assembly of point-like light sources forming a single encapsulated light source
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2115/00—Light-generating elements of semiconductor light sources
    • F21Y2115/10—Light-emitting diodes [LED]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/0001—Technical content checked by a classifier
    • H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/095—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00 with a principal constituent of the material being a combination of two or more materials provided in the groups H01L2924/013 - H01L2924/0715
    • H01L2924/097—Glass-ceramics, e.g. devitrified glass
    • H01L2924/09701—Low temperature co-fired ceramic [LTCC]

Definitions

  • the invention relates to an illumination system comprising a first transparent element and a second transparent element, while, in operation, light propagates from the first transparent element towards the second transparent element.
  • illumination systems are known per se. They are used, inter alia, as backlighting of (image) display devices, for example for television receivers and monitors.
  • Such illumination systems can particularly suitably be used as a backlight for non-emissive displays, such as liquid crystal display devices, also referred to as LCD panels, which are used in (portable) computers or (cordless) telephones.
  • non-emissive displays such as liquid crystal display devices, also referred to as LCD panels, which are used in (portable) computers or (cordless) telephones.
  • illumination systems are used for general lighting purposes, such as spot lights, flood lights and for large-area direct- view light emitting panels such as applied, for instance, in signage, contour lighting, and billboards.
  • LEDs can be light sources of distinct primary colors, such as, for example the well-known red (R), green (G), or blue (B) light emitters.
  • R red
  • G green
  • B blue
  • the light emitter can have, for example, amber or cyan as primary color.
  • These primary colors may be either generated directly by the light-emitting-diode chip, or may be generated by a phosphor upon irradiance with light from the light-emitting-diode chip. In the latter case, also mixed colors or white light is possible as one of the primary colors.
  • the light emitted by the light sources is mixed in the transparent element(s) to obtain a uniform distribution of the light while eliminating the correlation of the light emitted by the illumination system to a specific light source.
  • a controller with a sensor and some feedback algorithm in order to obtain high color accuracy.
  • US Patent Application US-A 2003/0 193 807 discloses a LED-based elevated omni-directional airfield light.
  • the known illumination system comprises a LED light source, a light transformer, a hemispherical optical window, a circuit and a base.
  • the light transformer includes a truncated hollow conical reflector, a curved reflective surface, and an optical element.
  • a light shaping diffuser, particularly a holographic diffuser, may be used as dispersing optical element.
  • the conical reflector has a truncated end facing the light source and a cone base opposite the truncated end.
  • the conical reflector axis is coincident with a light source axis, and light passes through an opening on the truncated end.
  • the curved reflective surface is between the truncated end and the cone base.
  • the surface reflects light from the light source in a limited angle omni-directional pattern with a pre-determined intensity distribution.
  • the optical element is adjacent the cone base in a plane perpendicular to the conical reflector axis, and disperses the light passing through the truncated hollow cone reflector.
  • an illumination system comprising: a first transparent element and a second transparent element; the first transparent element comprising a light-dispersing structure for broadening an angular distribution of light propagating from the first transparent element to the second transparent element via the light-dispersing structure; the light-dispersing structure having a fixed refractive index n ⁇ the second transparent element having a refractive index n 2 being electrically adaptable.
  • a light beam traveling from the first transparent element towards the second transparent element experiences a change in refractive index at an interface between the first and the second transparent element.
  • the difference in refractive index between the light-dispersing structure of the first transparent element and the second transparent element is changed.
  • the difference in refractive index between the first and the second transparent element influences the angular distribution of the light propagating from the first to the second transparent element.
  • the width of the light beam emitted by the illumination system can be varied by changing the difference in refractive indices between the light-dispersing structure of the first transparent element and the second transparent element.
  • the shape of the light beam would have the same shape in the second transparent element, i.e. a coUimated light beam would propagate through the first and the second transparent element.
  • n 2 of the second transparent element would be electrically adapted to be larger than the refractive index ni of the first transparent element, i.e. n 2 >n ⁇
  • the shape of the light beam would have a divergent character in the second transparent element, i.e. a coUimated beam would propagate through the first transparent element with the light-dispersing structure and a widening beam would propagate through the second transparent element.
  • the measure according to the invention allows the angular distribution of the light beam emitted by the illumination system to be influenced by electrically adapting the refractive index of the second transparent element.
  • the shape of a light beam emitted by the illumination system can be changed from, for instance, a "spot" light beam with a relatively narrow angular distribution to a "flood" light beam with a relatively broad angular distribution.
  • a further advantage of the illumination system according to the invention is that the change in the beam pattern can be done (quasi) continuously.
  • the shape of the light beam and/or the beam pattern of the illumination system can be adjusted dynamically.
  • a preferred embodiment of the illumination system according to the invention is characterized in that the second transparent element comprises a liquid crystal layer.
  • the orientation of a liquid crystal layer can be changed by applying a voltage across the liquid crystal layer resulting in a change in the effective refractive index experienced by a light beam traveling through such a layer.
  • two transparent electrodes are applied to enable the application of a voltage across the liquid crystal layer.
  • the electrodes are provided at opposite sites of a stack forming the liquid crystal layer.
  • the liquid crystal layer is in direct physical contact with the light-dispersing structure.
  • the electric field is applied across the stack of liquid crystal and the light dispersing structure.
  • the transparent electrodes are made of indium tin oxide (ITO).
  • ITO indium tin oxide
  • a very suitable liquid crystal layer is a so-called uniaxially oriented nematic liquid crystal layer.
  • a liquid crystal layer for use in the illumination system according to the invention can be made as follows. Substrates are covered by the transparent electrodes.
  • the first transparent element with a light dispersing property is located on top of one of the electrodes. Various techniques can be used for producing the transparent element.
  • ultra-violet (UV) replication techniques are employed using reactive molecules.
  • a layer of reactive molecules in the liquid form are brought between a surface of the electrode and a substrate containing a structure to be replicated.
  • the material solidifies forming the first transparent element.
  • uniaxial orientation of the molecules on the interfaces is induced with a tilt with respect to the surface plane.
  • Such a uniaxial planar tilted orientation in liquid crystals can be induced easily by first applying a thin layer of polymer and rubbing it uniaxially with for example a velvet cloth.
  • a surface of the first transparent element is provided with a further orientation layer.
  • a cell is constructed using a transparent electrode covered substrate with an orientation layer. Nematic. liquid crystal brought into such a cell becomes macroscopically oriented. Such a liquid crystal material can have uniaxial or twisted configurations as is well-known for persons skilled in the art of liquid crystals. In order to bring a twist into the liquid crystal, it is preferably doped with a suitable chiral dopant and the rubbing direction of the surfaces is adjusted accordingly. In such an orientation state, preferably, a liquid crystal is used with a positive dielectric anisotropy wherein application of electric field across such a layer change the orientation of the molecules from being perpendicular to the applied field to become oriented in the direction of the electric field.
  • liquid crystal molecules are used with a negative dielectric anisotropy wherein under the influence of the applied field the liquid crystal molecules change their orientation from being aligned in the direction of the electric field to become oriented perpendicular to the applied field.
  • n o ordinary
  • n e extraordinary
  • the extraordinary refractive index n e of such a uniaxially oriented nematic layer is the refractive index experienced by light polarized in the direction parallel to the long axis of the liquid crystal molecules.
  • the ordinary refractive index n o is observed for lateral polarization directions.
  • the sensitivity with respect to the polarization direction of light implies that upon applying an electric field in a direction perpendicular to the orientation direction of the liquid crystal layer with a positive dielectric anisotropy for light traveling in the direction of the applied field, light polarized in the orientation direction of the liquid crystal molecules the effective extraordinary refractive index shows a change while the effective ordinary refractive index for light polarized in the direction perpendicular to the orientation direction of the liquid crystal molecules remains unchanged.
  • a first manner is to use two cells each containing a light-dispersing structure and a liquid crystal layer.
  • a first preferred embodiment of the illumination system according to the invention is characterized in that it contains two cells in optical contact with each other and each cell being provided with a second transparent element which is in optical contact the first transparent element provided with a light-dispersing structure.
  • the cells are positioned so that the liquid crystal layers are oriented such with respect to each other that the optical characteristics are perpendicular to each other. In this manner, upon electrically switching each of the liquid crystal layers, a change is effected in the refractive index for all polarization directions.
  • a variation in this embodiment of the illumination system according to the invention is characterized in that between the first and second transparent elements with a light-dispersing structure an optical rotator is positioned causing a rotation of ninety degrees for plane polarized light.
  • the liquid crystal layers are oriented such with respect to each other that the optical characteristics are parallel to each other.
  • two anisotropic layers with a light-dispersing structure are provided at opposite sites of the liquid crystal layer.
  • a first preferred embodiment of the illumination system according to the invention is characterized in that the light- dispersing structure of the first transparent element comprises a first anisotropic layer, and a surface of the second transparent element facing the first transparent element is provided with a further light-dispersing structure comprising a second anisotropic layer, the anisotropic characteristics of the first and second anisotropic layer being oriented perpendicular with respect to each other.
  • the liquid crystal is in a configuration where the molecules rotate ninety degrees from one light-dispersing structure to the other.
  • the refractive indices of the anisotropic light dispersing structure are the same as that of the liquid crystal.
  • the refractive indices are perfectly matched and the cell functions as a so-called twisted nematic cell, therefore the cell is transparent.
  • the twisted nematic structure disappears and the liquid crystal molecules become aligned in the direction of the electric field whereby one of the polarization directions is influenced at one of the anisotropic light-dispersing element while the other polarization direction is influenced at the other light-dispersing element.
  • the light-dispersing structure comprises an array of micro-lenses or Fresnel-lenses, or, more general, the surface texture is causing a change in the beam shape in response to a difference in the refractive index between the materials forming the textured interface.
  • the light-dispersing structure comprises a holographic diffuser.
  • the holographic diffuser is a randomized holographic diffuser. The primary effect is a change in the beam shape. A secondary effect of the holographic diffuser is that a uniform spatial and angular color and light distribution is obtained.
  • the dimensions of the holographic diffuser, or beam shaper are so small that no details are projected on a target, thus resulting in a spatially and/or angularly smoothly varying, homogeneous beam pattern.
  • Figure 1A is a cross-sectional view of a first embodiment of the illumination system according to the invention
  • Figure IB is a cross-sectional view of a second embodiment of the illumination system according to the invention
  • Figures 1C and ID are two examples of the angular distribution of the light emitted by the illumination system according to the invention
  • Figure 2 is a cross-sectional view of a third embodiment of the illumination system according to the invention
  • Figure 3 is a cross-sectional view of a fourth embodiment of the illumination system according to the invention
  • Figure 4 is a cross-sectional view of a detail of an embodiment of the illumination system with two anisotropic layers and a light-dispersing structure
  • Figure 5 is a cross-sectional view of a detail of an embodiment of the illumination system with a replica isotropic layer
  • Figure 6 is a plot showing intensity as a function of angle at various voltages applied across a cell.
  • FIG. 1 A very schematically shows a cross-sectional view of a first embodiment of the illumination system according to the invention.
  • the illumination system comprises a plurality of light sources, for instance a plurality of light-emitting diodes (LEDs).
  • LEDs can be light sources of distinct primary colors, such as in the example of Figure 1A, the well-known red R, green G, or blue B light emitters.
  • the light emitter can have, for example, amber or cyan as primary color.
  • the primary colors may be either generated directly by the light-emitting-diode chip, or may be generated by a phosphor upon irradiance with light from the light-emitting-diode chip.
  • the LEDs R, G, B are mounted on a (metal-core) printed circuit board 4.
  • the LEDs have a relatively high source brightness.
  • each of the LEDs has a radiant power output of at least 100 mW when driven at nominal power.
  • LEDs having such a high output are also referred to as LED power packages.
  • the use of such high-efficiency, high-output LEDs has the specific advantage that, at a desired, comparatively high light output, the number of LEDs may be comparatively small. This has a positive effect on the compactness and the efficiency of the illumination system to be manufactured.
  • the heat generated by the LEDs can be readily dissipated by heat conduction via the PCB.
  • the (metal-core) printed circuit board 4 is in contact with the housing 3 of the illumination system via a heat-conducting connection.
  • so-called naked-power LED chips are mounted on a substrate, such as for instance an insulated metal substrate, a silicon substrate, a ceramic or a composite substrate.
  • the substrate provides electrical connection to the chip as well as acts a good heat transfer to a heat exchanger.
  • the embodiment of the illumination system as shown in Figure 1A comprises a first transparent element 1 functioning as a light mixing chamber filled with air with a refractive index of 1.
  • the first transparent element 1 is coated with a (diffuse) reflector 21 or are provided with a (diffuse) reflective coating.
  • the light emitted by the LEDs R, G, B is mixed in the first transparent element 1 resulting in a substantially uniform distribution of the light while eliminating the correlation of the light emitted by the illumination system to a specific LED R, G, B.
  • the first transparent element 1 is coupled to a second transparent element 2.
  • the first transparent element 1 comprises a light-dispersing structure 7 for broadening an angular distribution of light (also see Figure 1C and ID) propagating from the first transparent element 1 towards the second transparent element 2 via the light-dispersing structure 7.
  • the light-dispersing structure 7 is a holographic diffuser.
  • holographic diffusers Diffusers using holographic means are called holographic diffusers.
  • a holographic diffuser can have a very specific light-shaping function. Holographic diffusers shape light by controlling the energy distribution along the horizontal and vertical axes. Holographic diffusers increase the brightness of any traditional light source and greatly enhance the brightness and contrast of optical images. In addition, holographic diffusers have light- mixing properties.
  • the second transparent element 2 has a refractive index n 2 which is electrically adjustable.
  • the second transparent element 2 is a liquid crystal layer. The liquid crystal layer is powered by a applying a voltage V across the layer. By changing the LC orientation, the effective extraordinary refractive index n e (extraordinary) of the second transparent element 2 is changed.
  • Changing n e causes a change in the effective refractive index difference at the interface between the light-dispersing structure on the surface of the first transparent element and the second transparent element and, accordingly, influences the angular distribution of the light propagating from the first to the second transparent element 1, 2.
  • the effect of altering the effective refractive index difference between the light-dispersing structure 7 of the first transparent element 1 and the second transparent element 2 is used to vary the shape of the light beam emitted by the illumination system.
  • By electrically adapting the angular distribution of the light beam emitted by the illumination system it is possible to switch electrically between various angles of the light beam emitted by the illumination system (also see Figures 1C and ID).
  • FIG. IB very schematically shows a cross-sectional view of a second embodiment of the illumination system according to the invention.
  • the first transparent element is not an empty cavity as in Figure 1 A, but comprises a body of a dielectric material. Suitable materials are e.g. PMMA, PC, glass, epoxy, silicon gel, ceramic or combinations thereof.
  • three white LEDs Wi, W , W 3 are mounted on the printed circuit board 4.
  • the three white LEDs Wi, W 2 , W 3 are embedded in a body of a dielectric material.
  • the dielectric material has a collimating effect on the light emitted by the LEDs R, G, B.
  • a substantially coUimated beam arrives at the surface 11 of the first transparent element 1 facing the second transparent element 2. Due to the presence of the dielectric material, providing a reflector on the walls of the first transparent element 1 can be avoided.
  • the light-dispersing structure 7 of the first transparent element 1 and the second transparent element 2 are in optical contact coated with each other.
  • an index-matching material is employed promoting the optical contact.
  • Figure 1C and ID schematically shows two examples of the angular distributions of the light.
  • the example of Figure 1C shows a "spot" light beam with a relatively narrow angular distribution. This narrow angular distribution is achieved by starting with a substantially coUimated beam at the surface the surface 11 of the first transparent element 1 and having a relatively small gradient between the refractive index ni of the first transparent element 1 and the refractive index n 2 of the second transparent element 2.
  • the example of Figure ID shows a "flood" light beam with a relatively broad angular distribution.
  • FIG. 2 very schematically shows a cross-sectional view of a third embodiment of the illumination system according to the invention. Similar to Figure IB, the first transparent element 1 comprises a dielectric material.
  • the light-dispersing structure 7 in Figure 2 comprises an array of micro-lenses or a Fresnel-lens.
  • the effect of the array of micro-lenses or the Fresnel lens is that a uniform spatial and angular color and light distribution is obtained.
  • an array of micro-prisms is employed.
  • Figure 3 very schematically shows a cross-sectional view of a fourth embodiment of the illumination system according to the invention.
  • light emitted by the LEDs R, G, B is mixed in a dielectric optical collimator.
  • the combination of the light- dispersing structure 7 and the second transparent element 2 is placed at a distance from the dielectric optical collimator with the LEDs R, G, B.
  • the light-dispersing structure 7 can either be a holographic diffuser as shown in Figure 1A and Figure IB or an array of micro- lenses or a Fresnel-lens.
  • a wall 35 of the illumination system is coated with a (diffuse) reflector or is provided with a (diffuse) reflective coating.
  • the illumination system of Figure 3 is provided with a sensor 25 for measuring one or more optical properties of the light which, in operation, is emitted by the LEDs R, G, B.
  • a sensor 25 is coupled to control electronics (not shown in Figure 3) for suitably adapting the luminous flux of the LEDs R, G, B.
  • a feedback mechanism can be formed which is used to enhance the quality and the quantity of the light emitted by the illumination system.
  • the illumination system may be provided with a temperature sensor (not shown in Figure 3) for measuring the temperature of the LEDs.
  • a feedback and/or feed forward mechanism can be formed to enhance the quality and the quantity of the light emitted by the illumination system.
  • Figure 4 very schematically shows a cross-sectional view of a detail of an embodiment of the illumination system with a liquid crystal sandwiched between two anisotropic light-dispersing structures 13 and 23. In the example of Figure 4, two transparent electrodes 14, 24 for are shown applying a voltage across second transparent element 2.
  • the horizontal lines in the second transparent element 2 indicate the orientation of the liquid crystal layer.
  • the transparent electrodes 14, 24 comprise indium tin oxide.
  • the light-dispersing structure comprises a first anisotropic layer 13.
  • a surface 12 of the second transparent element 2 in optical contact with the light- dispersing structure is provided with a further light-dispersing structure comprising a second anisotropic layer 23.
  • the anisotropic characteristics of the first and second anisotropic layer 13, 23 are oriented perpendicular with respect to each other.
  • anisotropic light- dispersing structures are being made using so called liquid crystal gels. Such gels are produced using a liquid mixture of non reactive and reactive molecules.
  • FIG. 5 very schematically shows a cross-sectional view of a detail of an embodiment of the illumination system comprising a switchable cell and a light-dispersing structure.
  • two transparent electrodes 14, 24 for are shown applying a voltage across second transparent element 2.
  • Broken lines in the second transparent element 2 indicate the orientation of the liquid crystal layer.
  • the transparent electrodes 14, 24 comprise indium tin oxide (ITO).
  • the structure 7 has light-dispersing properties.
  • the light-dispersing structure 7 is made using acrylate replication technique. Acrylate monomer is placed on top of a substrate 42 with a transparent electrode 14. A mould with a light dispersing structure and is then placed on top of the monomer and polymerization is initiated using ultra-violet (UV) light. After the polymerization of the monomer, the mould is removed leaving behind a solid layer with a light-dispersing property. Subsequently an orientation layer 41 is provided by applying a layer of polyimide on top of the surface of the light-dispersing structure 7 and rubbing it uniaxially.
  • UV ultra-violet
  • a second substrate 43 provided with transparent electrodes and an orientation layer is used for producing a cell while using spacers to produce a gap between the two surfaces covered with the orientation layers.
  • the sell is subsequently filled with a nematic liquid crystal which is oriented uniaxially under the influence of the orientation layers. Two of such cells are optically coupled whereby the orientations of the liquid crystal molecules in two different cells are oriented orthogonal with respect to each other.
  • the refractive index ni of the layer with a light-dispersing structure 7 is chosen to be the same as the ordinary refractive index n 0 of the liquid crystal.
  • the extraordinary refractive index n. of the liquid crystal has a higher value than n 0 and the cell showing light scattering in the field of state.
  • Figure 6 shows the light intensity I (in cd/m 2 ) as a function of angle ⁇ (in °) for a coUimated beam of light at various voltages applied across a cell. It can be seen that with increasing voltage the intensity at half-width decreases. Not wishing to be held to any particular theory, it is believed that this effect is due to the fact that at high voltages molecules tend to become oriented in the direction of the applied field and the effective refractive index for the extraordinary ray tends to decrease to become the same as ordinary refractive index of the liquid crystal. In this manner, light travelling in the direction of the applied field at high voltages does not experience any change in refractive index at the interface.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • Power Engineering (AREA)
  • Liquid Crystal (AREA)
  • Diffracting Gratings Or Hologram Optical Elements (AREA)

Abstract

Un système d'éclairage possède un premier élément transparent (1) et un second élément transparent (2). Le premier élément transparent possède une structure de dispersion de la lumière (7) permettant d'élargir la distribution angulaire de la lumière se propageant du premier au second élément transparent en passant par la structure de dispersion de la lumière (7). La structure de dispersion de la lumière possède un indice de réfraction fixe n1. Le second élément transparent possède un indice de réfraction n2 adaptable au plan électrique. Le second élément transparent est de préférence une couche de cristaux liquides. La structure de dispersion de la lumière est de préférence en contact physique direct avec le second élément transparent. La structure de diffusion de la lumière est de préférence un diffuseur holographique, un groupement de micro-lentilles ou des lentilles de Fresnel.
PCT/IB2005/051803 2004-06-11 2005-06-02 Systeme d'eclairage WO2005121641A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP04102663.4 2004-06-11
EP04102663 2004-06-11

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WO2005121641A1 true WO2005121641A1 (fr) 2005-12-22

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TW (1) TW200612157A (fr)
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Cited By (26)

* Cited by examiner, † Cited by third party
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WO2007080543A1 (fr) * 2006-01-16 2007-07-19 Koninklijke Philips Electronics N.V. Module de lampe et dispositif d’eclairage comprenant celui-ci
WO2007107903A1 (fr) * 2006-03-23 2007-09-27 Koninklijke Philips Electronics N.V. Dispositif d'eclairage par led a couleur reglable
DE102006043402A1 (de) * 2006-09-15 2008-03-27 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Beleuchtungseinheit mit einem optischen Element
DE102007010039A1 (de) * 2007-03-01 2008-09-04 Osram Gesellschaft mit beschränkter Haftung Optoelektronische Vorrichtung und Regelungsverfahren
WO2008129438A1 (fr) 2007-04-19 2008-10-30 Koninklijke Philips Electronics N.V. Dispositif d'émission de lumière et procédé de commande
WO2009087584A1 (fr) * 2008-01-08 2009-07-16 Koninklijke Philips Electronics N.V. Dispositif de sortie lumineuse à éléments de réfraction commutables
WO2009109881A1 (fr) * 2008-03-07 2009-09-11 Koninklijke Philips Electronics N.V. Dispositif électroluminescent de couleur variable
WO2010035176A1 (fr) * 2008-09-23 2010-04-01 Koninklijke Philips Electronics N.V. Dispositif d’éclairage muni d’un élément de diffusion à variation électrique
WO2010058326A1 (fr) * 2008-11-20 2010-05-27 Koninklijke Philips Electronics N.V. Dispositif d’éclairage doté d’un cache à état commutable
EP2216592A3 (fr) * 2009-02-05 2011-05-04 e:cue control GmbH Lampe
US8111338B2 (en) 2007-09-20 2012-02-07 Koninklijke Philips Electronics N.V. Beam shaping device
ITPR20100074A1 (it) * 2010-10-19 2012-04-20 Coemar Spa Proiettore a led
WO2012011936A3 (fr) * 2010-07-23 2012-05-03 Cree, Inc. Commande de transmission de lumière pour masquer l'apparence de sources de lumière en semiconducteur
DE102011017098A1 (de) * 2011-04-14 2012-10-18 Osram Opto Semiconductors Gmbh Lichtemittierende Vorrichtung
CN103874878A (zh) * 2011-10-18 2014-06-18 皇家飞利浦有限公司 分裂波束照明器和照明系统
US8778601B2 (en) 2010-03-05 2014-07-15 Rohm and Haas Electronic Materials Methods of forming photolithographic patterns
US8878219B2 (en) 2008-01-11 2014-11-04 Cree, Inc. Flip-chip phosphor coating method and devices fabricated utilizing method
US9024349B2 (en) 2007-01-22 2015-05-05 Cree, Inc. Wafer level phosphor coating method and devices fabricated utilizing method
US9041285B2 (en) 2007-12-14 2015-05-26 Cree, Inc. Phosphor distribution in LED lamps using centrifugal force
US9159888B2 (en) 2007-01-22 2015-10-13 Cree, Inc. Wafer level phosphor coating method and devices fabricated utilizing method
US9944031B2 (en) 2007-02-13 2018-04-17 3M Innovative Properties Company Molded optical articles and methods of making same
EP2135000B1 (fr) 2007-04-03 2018-07-25 Philips Lighting Holding B.V. Dispositif d'émission de lumière
US10164158B2 (en) 2003-09-18 2018-12-25 Cree, Inc. Molded chip fabrication method and apparatus
CN109884820A (zh) * 2019-04-16 2019-06-14 京东方科技集团股份有限公司 透明显示面板及其制作方法
US10697615B1 (en) * 2018-05-08 2020-06-30 Elite Lighting Light fixture with LCD optic element
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US8042967B2 (en) 2006-01-16 2011-10-25 Koninklijke Philips Electronics N.V. Lamp module and lighting device comprising such a lamp module
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WO2007107903A1 (fr) * 2006-03-23 2007-09-27 Koninklijke Philips Electronics N.V. Dispositif d'eclairage par led a couleur reglable
DE102006043402B4 (de) 2006-09-15 2019-05-09 Osram Gmbh Beleuchtungseinheit mit einem optischen Element
DE102006043402A1 (de) * 2006-09-15 2008-03-27 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Beleuchtungseinheit mit einem optischen Element
US7645054B2 (en) 2006-09-15 2010-01-12 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Illuminating unit comprising an optical element
US9159888B2 (en) 2007-01-22 2015-10-13 Cree, Inc. Wafer level phosphor coating method and devices fabricated utilizing method
US9024349B2 (en) 2007-01-22 2015-05-05 Cree, Inc. Wafer level phosphor coating method and devices fabricated utilizing method
US9944031B2 (en) 2007-02-13 2018-04-17 3M Innovative Properties Company Molded optical articles and methods of making same
US7960680B2 (en) 2007-03-01 2011-06-14 Osram Gesellschaft mit beschränkter Haftung Optoelectronic device for emitting electromagnetic radiation with controllable emission intensity and control method
DE102007010039A1 (de) * 2007-03-01 2008-09-04 Osram Gesellschaft mit beschränkter Haftung Optoelektronische Vorrichtung und Regelungsverfahren
EP2135000B1 (fr) 2007-04-03 2018-07-25 Philips Lighting Holding B.V. Dispositif d'émission de lumière
JP4828654B2 (ja) * 2007-04-19 2011-11-30 コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ 光出力装置及び制御方法
US8665399B2 (en) 2007-04-19 2014-03-04 Koninklijke Philips N.V. Light output device and control method
WO2008129438A1 (fr) 2007-04-19 2008-10-30 Koninklijke Philips Electronics N.V. Dispositif d'émission de lumière et procédé de commande
US8111338B2 (en) 2007-09-20 2012-02-07 Koninklijke Philips Electronics N.V. Beam shaping device
US9041285B2 (en) 2007-12-14 2015-05-26 Cree, Inc. Phosphor distribution in LED lamps using centrifugal force
WO2009087584A1 (fr) * 2008-01-08 2009-07-16 Koninklijke Philips Electronics N.V. Dispositif de sortie lumineuse à éléments de réfraction commutables
US8878219B2 (en) 2008-01-11 2014-11-04 Cree, Inc. Flip-chip phosphor coating method and devices fabricated utilizing method
RU2518184C2 (ru) * 2008-03-07 2014-06-10 Конинклейке Филипс Электроникс Н.В. Светоизлучающее устройство переменного цвета
WO2009109881A1 (fr) * 2008-03-07 2009-09-11 Koninklijke Philips Electronics N.V. Dispositif électroluminescent de couleur variable
US8427605B2 (en) 2008-09-23 2013-04-23 Koninklijke Philips Electronics N.V. Illumination device with electrical variable scattering element
JP2012503290A (ja) * 2008-09-23 2012-02-02 コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ 電気的可変散乱素子を具備する照明装置
CN102159880B (zh) * 2008-09-23 2014-07-30 皇家飞利浦电子股份有限公司 具有电致可变散射元件的照明器件及其中电致可变散射元件的使用
WO2010035176A1 (fr) * 2008-09-23 2010-04-01 Koninklijke Philips Electronics N.V. Dispositif d’éclairage muni d’un élément de diffusion à variation électrique
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EP2216592A3 (fr) * 2009-02-05 2011-05-04 e:cue control GmbH Lampe
US8778601B2 (en) 2010-03-05 2014-07-15 Rohm and Haas Electronic Materials Methods of forming photolithographic patterns
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RU2624453C2 (ru) * 2011-10-18 2017-07-04 Филипс Лайтинг Холдинг Б.В. Светильник с расщепленным пучком и осветительная система
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