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
  • F21V13/00—Producing particular characteristics or distribution of the light emitted by means of a combination of elements specified in two or more of main groups F21V1/00 - F21V11/00
  • F21V13/02—Combinations of only two kinds of elements
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10H—INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
  • H10H20/00—Individual inorganic light-emitting semiconductor devices having potential barriers, e.g. light-emitting diodes [LED]
  • H10H20/80—Constructional details
  • H10H20/85—Packages
  • H10H20/8506—Containers
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10H—INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
  • H10H20/00—Individual inorganic light-emitting semiconductor devices having potential barriers, e.g. light-emitting diodes [LED]
  • H10H20/80—Constructional details
  • H10H20/85—Packages
  • H10H20/851—Wavelength conversion means
  • H10H20/8511—Wavelength conversion means characterised by their material, e.g. binder
  • H10H20/8512—Wavelength conversion materials
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10H—INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
  • H10H20/00—Individual inorganic light-emitting semiconductor devices having potential barriers, e.g. light-emitting diodes [LED]
  • H10H20/80—Constructional details
  • H10H20/85—Packages
  • H10H20/851—Wavelength conversion means
  • H10H20/8514—Wavelength conversion means characterised by their shape, e.g. plate or foil
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10H—INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
  • H10H20/00—Individual inorganic light-emitting semiconductor devices having potential barriers, e.g. light-emitting diodes [LED]
  • H10H20/80—Constructional details
  • H10H20/85—Packages
  • H10H20/855—Optical field-shaping means, e.g. lenses
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10H—INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
  • H10H20/00—Individual inorganic light-emitting semiconductor devices having potential barriers, e.g. light-emitting diodes [LED]
  • H10H20/80—Constructional details
  • H10H20/882—Scattering means

Definitions

• the present invention is directed to novel luminescent materials and compounds for light emitting devices, especially to the field of LEDs
• an illumination system comprising at least one light scattering and conversion plate comprising a) a first layer having scattering properties and no conversion properties and b) a second layer having conversion properties whereby the thickness A of the first layer and the thickness B of the second layer match
• a and B match A> 4*B, more preferred A> 7*B.
• layer and /or “plate” especially mean and/or include an object which extends in one dimension (i.e. the height) to ⁇ 40%, more preferred ⁇ 20% and most preferred ⁇ 10% than in any of the other dimensions (i.e. width and length).
• scattering especially means and/or includes the change of the propagation direction of light.
• converting especially means and/or includes the physical process of absorption of light and emitting of light in another wavelength area, e.g. due to radiative transitions that involve at least one ground state and at least one excited state and that may be described with a conf ⁇ gurational coordinate diagram showing the potential energy curves of absorbing and emitting centers as a function of the configurational coordinate.
• no conversion properties especially means and/or includes that >95%, more preferred >97%, more preferred >98% and most preferred >99% of all transmitted light passes the plate without being converted.
• Such an illumination system has shown for a wide range of applications within the present invention to have at least one of the following advantages: -
• the surprising result of one of the basic ideas underlying the present invention, i.e. separating scattering and converting is that for most application both a good forward emission together with an angular stability of the emission profile can be found.
• the overall setup of the illumination system can be kept simple and small -
• the lifetime of the illumination system is considerably extended because of improved heat dissipation properties and improved chemical stability additional functional layers can be applied on one layer only eliminating the risk of damaging the more expensive other layer.
• the second layer is in the optical path in between the primary light source and the first layer.
• the primary light source will in most applications be a blue LED; however, any devices known in the field to the skilled person in the art may be used.
• the first and/or second layer are essentially made out of a ceramic material.
• the term "essentially” in the sense of the present invention especially means >90 (wt.)-%, more preferably >95 (wt.)-%, yet more preferably >98 (wt.)-% and most preferred >99 (wt.)-%.
• ceramic material in the sense of the present invention means and/or includes especially a crystalline or polycrystalline compact material or composite material with a controlled amount of pores or which is pore free.
• polycrystalline material in the sense of the present invention means and/or includes especially a material with a volume density larger than 90 percent of the main constituent, consisting of more than 80 percent of single crystal domains, with each domain being larger than 0.5 ⁇ m in diameter and having different crystallographic orientations.
• the single crystal domains may be connected by amorphous or glassy material or by additional crystalline constituents.
• the ceramic material has a volume of > 0.005 mm 3 to ⁇ 8 mm 3 , more preferred > 0.03 mm 3 to ⁇ 1 mm 3 and most preferred > 0.08 mm 3 to ⁇ 0.18 mm 3 .
• the ceramic material has a density of >90% and ⁇ 100% of the theoretical density. This has been shown to be advantageous for a wide range of applications within the present invention since then the luminescent properties of the at least one ceramic material may be increased.
• the ceramic material has a density of >97% and ⁇ 100% of the theoretical density, yet more preferred >98% and ⁇ 100%, even more preferred >98.5% and ⁇ 100% and most preferred >99.0% and ⁇ 100%.
• the surface roughness RMS disruption of the planarity of a surface; measured as the geometric mean of the difference between highest and deepest surface features
• the surface(s) of the ceramic material is > 0.001 ⁇ m and ⁇ 1 ⁇ m.
• the surface roughness of the surface(s) of the at least one ceramic material is >0.005 ⁇ m and ⁇ 0.8 ⁇ m, according to an embodiment of the present invention >0.01 ⁇ m and ⁇ 0.5 ⁇ m, according to an embodiment of the present invention >0.02 ⁇ m and ⁇ 0.2 ⁇ m and according to an embodiment of the present invention >0.03 ⁇ m and ⁇ 0.15 ⁇ m.
• the specific surface area of the ceramic material is >10 "7 m 2 /g and ⁇ 0.1 m 2 /g.
• the thickness B of the second layer is >5 ⁇ m and ⁇ 80 ⁇ m. This has been shown to be advantageous for many applications within the present invention since by doing so the packing efficiency and side emission of the light scattering and conversion plate may greatly be increased and reduced, respectively.
• the thickness B of the second layer is >10 ⁇ m and ⁇ 50 ⁇ m.
• the thickness A of the first layer is
• the thickness A of the first layer is > 100 ⁇ m and ⁇ 300 ⁇ m.
• the scattering coefficient of the first layer is >0 and ⁇ IOOO cm "1 .
• the scattering coefficient s is determined by measurement of the reflectance Ro and/or the transmittance To of a thin layer with thickness A according to the equations:
• the scattering coefficient of the first layer is > 100 and ⁇ 500 cm "1 .
• the mean refractive index n of the first layer is >1.3 and ⁇ 2.5.
• the difference ⁇ n in refractive index between the refractive index of the first layer and the second layer is >0.03 and ⁇ 1. This has been shown to be advantageous for mixing the light from the primary light source and the converted light from the second layer for many applications.
• ⁇ n is >0.3 and ⁇ 0.5.
• the plate comprises a third layer provided in between the first and second layer and essentially made out of an adhesive material, preferably a silicone glue.
• This invention furthermore relates to method of producing a light scattering and conversion plate comprising the steps of a) Providing a first and second layer, whereby the thickness of the second layer is larger than desired b) Connecting the first and second layer, optionally by use of a third layer provided in between the first and second layer and essentially made out of an adhesive material c) Mechanically reducing the thickness of the second layer, e.g. by grinding By doing so, it has been shown for many applications that a light scattering and conversion plate according to the present invention can be made easily and effectfully even for small thicknesses of the second layer.
• An illumination system according to the present invention may be of use in a broad variety of systems and/or applications, amongst them one or more of the following:
• Fig. 1 shows a very schematic setup of an illumination system according to one embodiment of the present invention.
• Fig. 2 shows a detailled very schematic view of the light scattering and converting plate of Fig. 1
• Fig. 3 shows a photograph of a detail of a light scattering and converting plate according to Example I of the present invention.
• Fig.4 shows a photograph of a detail of a light scattering and converting plate according to Example II of the present invention.
• Fig. 5 shows the spatial radiation pattern of two LEDs according to Example I and II of the present invention and a comparative example
• Fig. 6 shows the Emission spectra of the two LEDs according to
• Example I and II of the present invention and the comparative example shows a CIE 1931 Chromaticity chart showing the Planckian locus of the two LEDs according to Example I and II of the present invention and the comparative example
• Fig. 1 shows a very schematic setup of an illumination system according to one embodiment of the present invention. Most of Fig. 1 is prior art and known to the skilled person and will therefore described only briefly. It is apparent that the illumination system of Fig. 1 is exemplarily only and the skilled person may use different parts or replace it at lib.
• the illumination system 1 comprises a thin film chip blue LED 20 upon which a light scattering and converting plate 10 is provided; both are covered by a lens.
• Fig. 2 shows a detailled very schematic view of the light scattering and converting plate of Fig. 1.
• the plate 10 comprises a first layer 12 (with a thickness A), a second layer 14 (with a thickness B) and in between a silicon glue layer 16.
• Fig. 2 is highly schematic and in most applications the actual dimensions will be much different. It is noted that the plate 10 is provided in the illumination system 1 so that the second layer 12 is in the optical path between the blue chip LED 20 and the second layer 14.
• Examples I and II which - in a merely illustrative fashion - shows several illumination systems of the present invention.
• a Y 288 Ce 0012 Al 5 O 12 layer (i.e. the second layer 14) was ground from both sides from a 1.1 mm thick wafer after sintering to 300 ⁇ m thickness.
• a 1 mm thick poly crystalline AI 2 O 3 layer (PCA, the first layer 12) with a mass density of 99.98 percent of the crystalline AI2O3 was ground to 150 ⁇ m.
• the first layer was coated with a Silicone layer (Shin Etsu KJR-9222A and KJR-9222A, mixing ratio 1 :1), the second layer was attached and the silicone layer was hardened at a temperature of 100 0 C for one hour and cured at 150 0 C for 2 hours.
• the second layer 14 was further ground to a thickness of 17 (Example I) and 30 ⁇ m (Example II), respectively. Then both plates were diced to 0.99 x 0.99 mm 2 , mount on a blue TFFC
• Example I was made in analogy to the inventive Examples.
• the second layer was set to a thickness of 120 ⁇ m and made out of Y 2842 Gd 0 15 Ce 0 O08 Al 5 O 12 (i,e. a lower Cerium- Content to match the higher thickness)
• Fig. 3 shows a photograph of a detail of a light scattering and converting plate according to Example I of the present invention.
• the light scattering and converting plate has an overall thickness of about 205 ⁇ m, whereby the first layer is about 140 ⁇ m thick, the second layer about 30 ⁇ m and the silicon layer about 35 ⁇ m.
• Fig.4 shows a photograph of a detail of a light scattering and converting plate according to Example II of the present invention.
• the light scattering and converting plate has also an overall thickness of about 205 ⁇ m; however, here the first layer is about 146 ⁇ m thick, the second layer about 17 ⁇ m and the silicon layer about 42 ⁇ m.
• Fig. 5 shows the spatial radiation pattern of the two LEDs according to Example I and II of the present invention and a comparative example. Due to emission from the faces of the Lumiramic converter plate of the comparative example the radiative flux under large emission angle is higher compared to the flux under large angles emitted by LEDs with converter plates of Example I and Example II of the present invention.
• Fig. 6 shows the Emission spectra of the two LEDs according to
• Example I and II of the present invention and the comparative example.
• the total conversion strength is low and the peak of the emitted blue light is much larger than the maximum of the converted light.
• the 30 ⁇ m Example both peaks are about equal, which shows the high efficacy of the light scattering and conversion plate.
• Fig. 7 shows a CIE 1931 Chromaticity chart showing the Planckian locus and the color points of the two LEDs according to the Example I and II of the present invention and the comparative example. It can be seen that due to the inventive scattering and light emitting plate a low color temperature of about 4000K has been realized with the 30 ⁇ m Example, whereas only a small change in size of the conversion layer 12 (i.e. to 17 ⁇ m) leads to a dramatic increase of color temperature to about 10000K. Variation of thickness and Cerium concentration gives access to white LED production of a color temperature ranging from above 10 00OK to 4000K and below.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Led Device Packages (AREA)
• Optical Elements Other Than Lenses (AREA)
• Luminescent Compositions (AREA)
• Electroluminescent Light Sources (AREA)
• Laminated Bodies (AREA)
• Circuit Arrangement For Electric Light Sources In General (AREA)
• Planar Illumination Modules (AREA)
• Non-Portable Lighting Devices Or Systems Thereof (AREA)

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• 2010
  • 2010-05-17 KR KR1020117030162A patent/KR101747688B1/ko active Active
  • 2010-05-17 RU RU2011151606/28A patent/RU2531848C2/ru active
  • 2010-05-17 WO PCT/IB2010/052167 patent/WO2010134011A2/en not_active Ceased
  • 2010-05-17 CN CN201080021909.5A patent/CN102428583B/zh active Active
  • 2010-05-17 US US13/320,803 patent/US8721098B2/en active Active
  • 2010-05-17 EP EP10726270.1A patent/EP2436047B1/en active Active
  • 2010-05-17 JP JP2012511387A patent/JP2012527763A/ja active Pending
  • 2010-05-17 BR BRPI1007686-7A patent/BRPI1007686B1/pt active IP Right Grant
• 2014
  • 2014-03-25 US US14/224,120 patent/US9482411B2/en active Active
• 2016
  • 2016-10-28 US US15/337,435 patent/US9966512B2/en active Active

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