Classifications

• • 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
  • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
  • G02B6/0005—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being of the fibre type
  • G02B6/001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being of the fibre type the light being emitted along at least a portion of the lateral surface of the fibre
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
  • F21S43/00—Signalling devices specially adapted for vehicle exteriors, e.g. brake lamps, direction indicator lights or reversing lights
  • F21S43/10—Signalling devices specially adapted for vehicle exteriors, e.g. brake lamps, direction indicator lights or reversing lights characterised by the light source
  • F21S43/13—Signalling devices specially adapted for vehicle exteriors, e.g. brake lamps, direction indicator lights or reversing lights characterised by the light source characterised by the type of light source
  • F21S43/14—Light emitting diodes [LED]
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
  • F21S43/00—Signalling devices specially adapted for vehicle exteriors, e.g. brake lamps, direction indicator lights or reversing lights
  • F21S43/20—Signalling devices specially adapted for vehicle exteriors, e.g. brake lamps, direction indicator lights or reversing lights characterised by refractors, transparent cover plates, light guides or filters
  • F21S43/235—Light guides
  • F21S43/236—Light guides characterised by the shape of the light guide
  • F21S43/237—Light guides characterised by the shape of the light guide rod-shaped
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
  • F21S43/00—Signalling devices specially adapted for vehicle exteriors, e.g. brake lamps, direction indicator lights or reversing lights
  • F21S43/20—Signalling devices specially adapted for vehicle exteriors, e.g. brake lamps, direction indicator lights or reversing lights characterised by refractors, transparent cover plates, light guides or filters
  • F21S43/235—Light guides
  • F21S43/242—Light guides characterised by the emission area
  • F21S43/245—Light guides characterised by the emission area emitting light from one or more of its major surfaces

Definitions

• the invention relates to lighting devices which comprise at least one light guide coupled to at least one light source.
• the term "lighting device” is understood here to mean a light device capable of providing a lighting or signaling function, or a decorative light effect.
• At least one light guide which extends along a line (possibly of curvilinear type) and which has two opposite ends, at least one of which is coupled to a source of light charged to supply photons, and a heart delimited by front and rear faces.
• Photons propagate in the heart by total reflection on the inner faces and are transferred outwardly to at least partially fill a photometric function and / or ensure a luminous style effect.
• This type of light guide offers neither a good performance nor a variety of light style effects because of the difficulty of transferring photons to the outside via its front, it has been proposed to place a concave reflector in front of his face back or to define a relief on its back face to reflect the photons in a preferred way to its front face.
• These solutions certainly make it possible to significantly improve the photon transfer efficiency towards the front face, but they do not make it possible to substantially increase the variety of luminous style effects and thus the possibilities of generating light signatures. Thus, they do not easily allow the introduction of depth effects, volume effects (or 3D) or brightness gradient effects, especially when certain photometric performance must be achieved to meet regulation.
• the invention therefore aims to propose an alternative solution to improve the situation.
• a lighting device comprising at least one light guide extending along a line and having two opposite ends, at least one of which is coupled to a source of light generating photons, and a delimited core. by front and back faces.
• the front face has a first conical profile and the rear face is metallized and has a second conical profile associated with a focus line located in the heart, and
• the heart comprises on at least part of the focus line at least one diffusion element which is able to return certain photons which reach it towards the rear face so that the latter reflects them towards the front face following directions which are substantially parallel to a predefined direction, to define at least one light beam at least partially filling a photometric function and / or providing a light style effect.
• a very large variety of luminous style effects (3D effects, depth effect, control of the luminous density of the photometric function, control of the homogeneity) and / or different photometric functions can thus be obtained without additional components must be used.
• the lighting device according to the invention may comprise other characteristics that can be taken separately or in combination, and in particular:
• each diffusion element can be defined in the core in the form of a cloud of scattering points by a laser beam
• each diffusion element may have an overall shape which is chosen from (at least) a frustoconical shape and a cylindrical shape;
• the diffusion elements may have a global shape and / or a variable density and / or dispersion depending on their distance by relation to the light source;
• the diffusion elements may have a cross section which increases with their distance from the light source
• the density of the scattering elements can increase with their distance from the light source
• the dispersion of the diffusion elements can decrease with their distance from the light source
• the first profile can be semi-circular
• the second profile can be semi-parabolic
• it may comprise at least two light guides coupled respectively to at least two light sources;
• the end which is opposite to the light source can be metallized in order to reflect towards the heart the photons which reach it.
• the two ends may be respectively coupled to two light sources.
• the invention also proposes an optical unit comprising at least one lighting device of the type of that presented above.
• the invention may for example be used in the field of vehicles, possibly of the automotive type.
• FIG. 1 schematically illustrates, in a perspective view, an exemplary embodiment of a lighting device according to the invention
• FIG. 2 schematically illustrates, in a sectional view, photon paths reflected by a diffusion element of the lighting device of FIG. 1.
• the object of the invention is to provide a lighting device D with a light guide (s) GL, which makes it possible, at least partially, to fill a photometric function and / or to allow many lighting style effects.
• the lighting device D is intended to be part of an optical block (no shown) of a vehicle, possibly of automobile type. But the invention is not limited to this application.
• a lighting device D according to the invention can indeed equip any type of system, equipment or device, including interior or exterior building walls (possibly by providing additional sealing means to protect the electronics). .
• the optical block can be both a headlight (or front projector), a taillight.
• a lighting device D can provide, or participate in, a daytime running light function (or DRL (for "Daytime running Light (Gold Lamp)" - light signaling automatically lit when the vehicle is put in operation)) or third brake light (rear).
• the direction X is a so-called longitudinal direction
• the direction Y is a so-called transverse direction, which is substantially perpendicular to the longitudinal direction X
• the direction Z is a so-called vertical direction, which is substantially perpendicular to the directions longitudinal X and transverse Y.
• FIG. 1 shows an exemplary embodiment of a lighting device D according to the invention.
• a lighting device D comprises at least one light guide GL and at least one light source SL.
• the (lighting) device D has only one light guide GL. But it could comprise several, at least two, possibly arranged in a sheet, possibly of different shapes, and each having at least one end associated with a light source SL.
• Each light guide GL has two ends E1 and E2 which are opposed to one another and at least one of which is coupled to a light source SL.
• the (light) photons which are generated by a light source SL, penetrate through an end face of the light guide GL, which is here at its first end E1, and propagate internally in its heart CG which is surrounded by FV front and rear faces. Note that the photons are guided in total reflection within the light guide GL.
• Each light source SL may comprise at least one light-emitting diode (or LED) or a laser diode whose photon-emitting end is placed substantially against an end face of the first end E1 of the light guide GL, which has been chosen. for the injection of photons.
• This support plate may for example be a printed circuit board, of the PCB type ("Printed Circuit Board”), rigid or flexible (“type” Flex ").
• Each light-emitting diode or laser diode SL may be coupled to the light guide GL either directly, for example by gluing or by embedding in a hole defined in its injection end face, or indirectly, for example via the support plate. Furthermore, each light-emitting diode or laser diode SL may be arranged to emit white light or a colored light. On the other hand, in the presence of at least two light-emitting diodes or laser diodes SL, the latter can be arranged to emit different or identical light colors.
• Each (the) light guide GL extends along a line which, in the nonlimiting example illustrated, is a straight line parallel to the transverse direction Y. But each light guide GL could extend along a curvilinear line presenting the less a curvature. When the line has several curvatures (at least two), the latter may be possibly in different planes. Note that in the presence of several light guides GL, the latter (GL) may have different shapes (and therefore possible curvatures).
• each GL light guide can be made of plastic or glass.
• the front face FV of the light guide GL has a first conical profile and the rear face FR is metallized and has a second conical profile associated with a focus line LF which is located in the core CG.
• Each conical profile is obtained by "extruding" within a conical surface in a given direction.
• the rear face FR is defined by a displacement of a conic along the line along which the light guide GL extends, the latter does not therefore have a single focus but a focus line LF.
• the rear face FR is defined by the translation of a parabola along the transverse direction Y and therefore the light guide GL has a linear LF line of focus (parallel to the transverse direction Y).
• the first profile is semi-circular and the second profile is semi-parabolic. But other profiles can be considered when it comes to conical profiles.
• the core CG comprises, on at least part of the focus line LF, at least one diffusion element ED which is adapted to return certain photons which reach it towards the rear face FR so that the latter (FR) reflect them towards the front face FV following directions which are substantially parallel to the predefined direction (here X), to define at least one light beam at least partially filling a photometric function and / or providing a light style effect.
• at least one diffusion element ED which is adapted to return certain photons which reach it towards the rear face FR so that the latter (FR) reflect them towards the front face FV following directions which are substantially parallel to the predefined direction (here X), to define at least one light beam at least partially filling a photometric function and / or providing a light style effect.
• the expression "fill at least partially” means here that the device D provides at least one beam which will then be treated (for example by a reflector or a screen or a lens of its optical block) in order to perform a photometric function, or else that is not processed and therefore performs a photometric function.
• a "diffusion element” is here a defined element in the mass of the heart CG in order to deflect photons that reach it in any direction of space. Once illuminated, the diffusion element ED therefore behaves as a secondary light source, part of the radiation of which will reach the rear face FR (metallized).
• this rear face FR is a parabolic cylinder and the light source is substantially located on the focus line LF of the parabola, the photons reflected by this light source are reflected by the rear face FR in a direction which is substantially parallel to the light source. axis of the parable.
• the ED element line (s) and the rear face FR shine.
• each diffusion element ED is produced in the form of a cloud of scattering points (or centers) by means of a laser beam which is focused substantially on the focal line LF in order to locally burn or deform the material constituting the CG heart.
• the diffusion elements ED may have different global shapes as soon as they are adapted to the scattering of photons, as shown in FIG. 2.
• the typical size of a diffusing point (or center) is of the order micron.
• the spatial distribution of scattering points constituting an ED diffusion element may be of frustoconical or cylindrical shape.
• the axis of the cones or cylinders is substantially aligned in the transverse direction Y.
• the diameter of the cross section (in the plane XZ) of a diffusion element ED can be equal to about 1 mm.
• the diffusion elements ED may have a global shape and / or a density and / or a dispersion which varies (nt) as a function of their distance from the light source SL, according to the needs, and in particular according to the desired light style effect.
• the diffusion elements ED may have a cross section (in the XZ plane) which increases with their distance from the light source SL, so as to provide at the output of the front face FV at least one light beam reflected of substantially constant intensity, and therefore homogeneous. It will be understood, in fact, that the further away the light source SL, the lower the number of photons is, and therefore the larger the cross section of a diffusion element ED must be to increase the probability that it can be reached by photons.
• the density of a diffusion element ED (that is to say the number of scattering points of its cloud per mm 2 ) can increase with the distance of the latter (ED) from the light source SL.
• This also makes it possible to provide at the output of the front face FV at least one reflected light beam whose luminance is substantially constant, and therefore the appearance lit homogeneous. It will be understood, in fact, that the further away the light source SL, the lower the number of photons is, and therefore the greater the density of a diffusion element ED must be large to increase the probability that it can be reached by photons at constant volume.
• the dispersion (or the distance between) of the diffusion elements ED may decrease with the distance of the latter (ED) relative to the light source SL.
• This also makes it possible to offer at the output of the front face FV at least one reflected light beam whose luminance is substantially constant, and therefore the aspect lit homogeneous. It will be understood that the further away from the light source SL, the lower the number of photons, and therefore the smaller the dispersion of the scattering elements ED must be to increase the probability that they may be reached by photons, at constant volume.
• volume effect means a volume effect giving an observer an impression of mass and / or thickness and / or fleshiness when the device D operates.
• the invention offers several advantages, among which:

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• General Engineering & Computer Science (AREA)
• Optics & Photonics (AREA)
• Microelectronics & Electronic Packaging (AREA)
• General Physics & Mathematics (AREA)
• Planar Illumination Modules (AREA)
• Non-Portable Lighting Devices Or Systems Thereof (AREA)

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• 2012
  • 2012-08-01 FR FR1257467A patent/FR2994247B1/fr not_active Expired - Fee Related
• 2013
  • 2013-07-22 WO PCT/FR2013/051756 patent/WO2014020260A1/fr active Application Filing
  • 2013-07-22 CN CN201380049292.1A patent/CN104813100B/zh not_active Expired - Fee Related
  • 2013-07-22 EP EP13747471.4A patent/EP2880359A1/de not_active Withdrawn

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