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
• • 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
  • G02B6/0011—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 planar or of plate-like form
  • G02B6/0033—Means for improving the coupling-out of light from the light guide
  • G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
  • G02B6/0055—Reflecting element, sheet or layer
• • 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
• • 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
  • G02B6/0011—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 planar or of plate-like form
  • G02B6/0033—Means for improving the coupling-out of light from the light guide
  • G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
  • G02B6/0051—Diffusing sheet or layer
• • 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
  • G02B6/0011—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 planar or of plate-like form
  • G02B6/0066—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 planar or of plate-like form characterised by the light source being coupled to the light guide
  • G02B6/0073—Light emitting diode [LED]
• • 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
  • G02B6/0011—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 planar or of plate-like form
  • G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
  • G02B6/0015—Means for improving the coupling-in of light from the light source into the light guide provided on the surface of the light guide or in the bulk of it
  • G02B6/0018—Redirecting means on the surface of the light guide
• • 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
  • G02B6/0011—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 planar or of plate-like form
  • G02B6/0075—Arrangements of multiple light guides
  • G02B6/0076—Stacked arrangements of multiple light guides of the same or different cross-sectional area

Definitions

• the invention relates to an arrangement with a semiconductor chip which is adapted to emit light during operation, and a cover layer, which lies opposite a light-emitting surface of the semiconductor chip, so that light emitted by the semiconductor chip penetrates into the cover layer.
• Such arrangements correspond to a conventional structure of semiconductor devices, wherein the cover protects the semiconductor chip and provides for a coupling of the light.
• One application of semiconductor light-emitting devices is the backlighting of displays.
• the light generated by a light-emitting diode must be distributed over a large area, using light guide plates or light guide foils.
• the light is radiated from such a light guide plate over a large area from behind to the back of a display layer.
• Such an arrangement is known from JP 08007614.
• light is coupled laterally into the light guide plate.
• a diffuser raster which is printed on the underside of the light guide plate, ensures an improved coupling of the light.
• the arrangement is that it is relatively large and expensive.
• the object of the invention is to provide an arrangement with a semiconductor chip, which can be used as a backlight unit, and which is constructed simpler and smaller.
• a light-deflecting structure is provided in a region of the covering layer which overlaps the chip, by means of which light which has penetrated into the covering layer is deflected in the direction of the longitudinal extent of the covering layer.
• the cover layer acts as a light guide and is adapted to radiate the light distributed over the top of the cover layer.
• the inventive design of the arrangement is small and can be made in one piece. It is not necessary to interconnect a light emitting diode and a light guide plate, but the cover layer of the semiconductor chip simultaneously performs the function as a light guide plate or foil.
• the deflecting structure ensures that light coupled into the covering layer is not emitted in the same direction but is deflected into the covering layer, so that it is distributed over the longitudinal extent of the covering layer and thus also decoupled in areas of the covering layer remote from the chip can. It is advantageous if an optically structured film which contains the covering layer is in direct contact with the semiconductor surface or is fixed with a contact layer connected to the semiconductor surface. The foil and the semiconductor chip thus form an integral unit.
• the semiconductor chip is a substrateless thin-film chip which preferably has two main emission directions lying opposite one another.
• a thin-film light-emitting diode chip is characterized in particular by the following characteristic features:
• the epitaxial layer sequence has a thickness in the range of 20 microns or less, in particular in the range of 10 microns;
• the epitaxial layer sequence includes at least one semiconductor layer having at least one surface which has a blending structure which ideally results in an approximately ergodic distribution of the light in the epitaxial epitaxial layer sequence, i. it has as ergodically stochastic scattering behavior as possible.
• a thin-film light-emitting diode chip is to a good approximation a Lambert surface radiator.
• the design as a thin-film chip has the advantage that the arrangement is very thin.
• the design as a double-sided emitter chip has the advantage that one with the invented backlight unit formed in accordance with the invention arrangement can emit light in two directions or, if light is to be emitted in only one direction, losses in the otherwise used substrate can be avoided.
• a reflective coating is provided on the upper side of the cover layer facing away from the semiconductor chip, so that radiation in the main emission direction of the semiconductor chip in the area above the semiconductor chip is prevented or reduced.
• the light-deflecting structure is preferably realized by optical elements which are integrated in the cover layer, wherein in particular prisms, lenses or diffraction gratings can be used.
• the light-deflecting structure may be formed in the cover layer itself, but also on the layer or between the semiconductor chip and the cover layer.
• the cover layer has a holographic structuring.
• the diffusers scatter light in different directions, resulting in a particularly even radiation characteristic.
• a combination of a plurality of films is provided as the cover layer, which has a different structuring and / or substructure. have different refractive indices.
• the interface between the films causes additional reflections and refractions.
• a converter material may be provided in the cover layer, which has a phosphor which emits light of a second wavelength after excitation by light of a first wavelength.
• a converter material which consists of a primary radiation emitted by the semiconductor chip and a secondary radiation generated by the phosphor.
• Such mixed light can be, for example, white light, which consists for example of blue primary radiation and yellow secondary radiation.
• FIG. 1 shows a schematic representation of an arrangement with a semiconductor chip and a light-conducting cover layer
• FIG. 2 shows an arrangement according to the invention with a mirror on the upper side of the covering layer
• FIG. 3 shows an arrangement according to the invention with a prismatic structure in the covering layer
• FIG. 4 shows an arrangement according to the invention with volume diffusers in the covering layer
• FIG. 5 shows an arrangement according to the invention with a multi-layer structure and a prism structure
• FIGS. 6A to 6F show various examples of a light-deflecting structure
• FIG. 7 shows a further embodiment of a light-deflecting structure
• FIG. 8 shows an arrangement according to the invention with a thin-film semiconductor chip emitting on both sides
• FIG. 9 shows an arrangement according to the invention with a converter layer
• FIG. 10 shows an arrangement according to the invention with two converter layers
• Figure 11 shows an inventive arrangement with flexible interconnects.
• the semiconductor chip shows the basic structure of an inventive arrangement with a semiconductor chip and a cover layer is shown.
• the semiconductor chip consists of a layer stack, two layers being shown in the embodiment shown.
• its thickness is preferably less than 20 microns, for example, seven microns. But it can also be used a much thicker semiconductor chip, for example, has a thickness of 150 microns.
• the semiconductor chip 1 With its upper side, the semiconductor chip 1 is connected to a cover layer 2, which consists of an optically transparent or partially transparent material.
• the covering layer 2 performs the function of distributing the light emitted by the semiconductor chip 1 over a large area so that it can be used, for example, for backlighting a display.
• the emission direction of the semiconductor chip 1 to its surface 3 is mainly perpendicular to its light-emitting top side or underside and not in the direction of the longitudinal extent of the cover layer 2.
• a light-deflecting structure 4 is provided in the region of the semiconductor chip, by which the light is deflected around itself spread out the cover layer, wherein the cover layer acts as a light guide plate or foil.
• transparent materials can be used as the material for the covering layer, but also semi-clear, transparent materials, for example with a haze effect, can be used, whereby the haze effect is caused, for example, by inhomogeneities in the material. It is important that they are translucent materials, which may also contain phosphors, for example.
• the cover layer preferably has a thickness between 30 microns and 300 microns.
• the arrangement of Figure 1 is designed to emit light mainly upwards. For this reason, a silver coating 6 is provided on the underside of the covering layer 5. hen, so that light is prevented from leaving the cover layer 2 down. Thus, light can only exit at the upper side 5.
• a light-reflecting layer so as to prevent radiation down. Instead, all the light is to be coupled into the cover layer 2 and deflected in the direction of its longitudinal extent.
• FIG. 2 shows how it can be prevented that light is visible predominantly in the main emission direction of the semiconductor chip 1 on the upper side of the covering layer 2.
• a reflective coating 7 is provided on the upper side of the covering layer 2 in the region above the semiconductor chip, which reflects the light incident there again downwards and thus gives the possibility to redirect the light further in the longitudinal extent of the covering layer 2. In this way it is prevented that in the region of the semiconductor chip 1, a light spot on the upper side of the cover layer is visible.
• the semiconductor chip is provided with two contact surfaces 8 in order to supply the semiconductor chip with an operating current.
• the arrangement of the contact surfaces can be seen schematically, of course, the contacts must be connected to the relevant areas for a power supply of the semiconductor chip, that is, one of the contact surfaces must be in communication with the upper layer of the semiconductor chip 1.
• the gap between the semiconductor chip and the cover layer 2 may be filled with a coupling medium 12 in order to establish a connection between the semiconductor chip 1 and the cover layer 2.
• the chip shown in the embodiment of Figure 2 has two contact surfaces, both of which are arranged on the underside of the chip 1. Other chips are designed so that a contact on the top and one on the bottom must be made.
• the coupling layer 12 is preferably used in order to arrange optically transparent but electrically conductive structures there, which serve for contacting the upper side of the semiconductor chip 1.
• the light-conducting foil shown in FIG. 2 consists of the covering layer 2 on the one hand and a second layer 10 on the other hand, so that a two-ply foil is formed.
• the interface between the cover layer 2 and the underlying layer 10, which forms the lower end of the cover layer 2, as well as the underside of this layer 10 may be structured or coated in order to influence the beam path of the light in the cover layer 2 in the desired manner.
• prisms 9 are formed in the cover layer 3 in the region above the semiconductor chip 1, which due to a jump in the refractive index at the interfaces formed by the prisms, the light emitted from the semiconductor chip 1 in the direction of the longitudinal extent of Cover layer 2 break.
• diffuser particles 11 are provided in the cover layer 2, which effect a scattering of the light emitted by the semiconductor chip 1.
• Diffuser particles consist for example of titanium dioxide. This has a high refractive index of approximately 2.8, which causes total reflections or at least strong refractions to occur at the boundary surfaces of the diffuser particles to the material of the cover layer 2, so that incident light is deflected.
• a two-layer cover layer 2 is provided.
• the lower layer is provided with prisms as described with reference to FIG. 3, while the upper layer has concave depressions 15 facing the prism depressions.
• the recesses in the upper layer act as lenses and can be used to additionally influence the emission characteristic.
• FIGS. 6A to 6F Various light-deflecting structures are shown in FIGS. 6A to 6F, which can be used within the scope of the invention, in order to deflect the light emitted by the semiconductor chip 1 in the longitudinal extent of the covering layer.
• a semiconductor chip 1 is connected via a coupling layer 12 with the cover layer 2.
• the respective embodiment of the cover layer 2 is different.
• a transparent film for example a glass film
• covering layer 2 which is provided on the upper side.
• te is optically structured.
• the glass sheet is optically structured on the underside.
• the optical structuring is provided both on the bottom and on the top. The structuring can be designed in such a way that the coupling-out efficiency of the chip is increased.
• FIG. 6D shows an exemplary embodiment in which a schematically illustrated layer of a photonic crystal is provided on the upper side.
• FIG. 6E shows an arrangement in which both an optical structuring within the cover layer and a photonic crystal on the upper side are provided.
• FIG. 6F shows an advantageous embodiment in which additionally a converter layer and the electrical layers are provided (to the inventor: Can you please add a paragraph to this)
• the surface of the semiconductor chip 1 is provided with a roughening structure and brought into contact with a structured side of a covering layer 2. Due to the different interface combinations, the light distribution in the covering film 2 is influenced. Regular or randomly structured surfaces are possible.
• FIG. 8 shows a two-sided emitting substrateless semiconductor chip in thin-film technology, which is covered from both sides.
• FIGS. 9 and 10 show that the arrangement according to the invention can also be used with converter layers which convert part of the primary beams generated by the semiconductor chip into secondary radiation, mixed light being emitted from the primary and secondary radiation. It can be white light consisting of blue primary radiation and yellow secondary radiation.
• the converter layer 13 is arranged between the semiconductor chip 1 and the cover layer 2.
• the converter material used is preferably an inorganic phosphor. In the embodiment according to FIG. 10, two converter layers are provided in order to enable a more complex color mixture. Also, the second converter layer can be used to convert a UV component in the primary radiation into visible light so as to achieve a higher efficiency.
• thin, planar, three-dimensionally configurable lighting elements can be produced in combination with flexible conductor tracks 15.
• a cylindrical arrangement can be produced which emits light over the entire lateral surface.
• backlighting that follows a curved surface.
• An exemplary application is the use in car headlights or taillights. But also in general lighting such lighting elements are versatile because of their three-dimensional deformability.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Engineering & Computer Science (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Led Device Packages (AREA)
• Semiconductor Lasers (AREA)
• Planar Illumination Modules (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (2)

Family

ID=39496079

Family Applications (1)

Country Status (8)

Cited By (5)

Families Citing this family (18)

Citations (1)

Family Cites Families (28)

• 2007
  • 2007-03-06 DE DE102007010755A patent/DE102007010755A1/de not_active Withdrawn
• 2008
  • 2008-01-23 JP JP2009552056A patent/JP2010520627A/ja active Pending
  • 2008-01-23 WO PCT/DE2008/000124 patent/WO2008106915A2/de not_active Ceased
  • 2008-01-23 CN CN200880006942.3A patent/CN101627326B/zh not_active Expired - Fee Related
  • 2008-01-23 EP EP08706792.2A patent/EP2130072B1/de not_active Ceased
  • 2008-01-23 US US12/528,960 patent/US8393748B2/en not_active Expired - Fee Related
  • 2008-01-23 KR KR1020097020697A patent/KR20090130016A/ko not_active Ceased
  • 2008-02-27 TW TW097106778A patent/TW200845431A/zh unknown

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Non-Patent Citations (1)

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