WO2009107038A1 - Boîtier de diode électroluminescente - Google Patents

Boîtier de diode électroluminescente Download PDF

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Publication number
WO2009107038A1
WO2009107038A1 PCT/IB2009/050672 IB2009050672W WO2009107038A1 WO 2009107038 A1 WO2009107038 A1 WO 2009107038A1 IB 2009050672 W IB2009050672 W IB 2009050672W WO 2009107038 A1 WO2009107038 A1 WO 2009107038A1
Authority
WO
WIPO (PCT)
Prior art keywords
light
light emitting
emitting diode
filter
diode package
Prior art date
Application number
PCT/IB2009/050672
Other languages
English (en)
Inventor
Joseph L. A. M. Sormani
Robertus G. Alferink
Ramon P. Van Gorkom
Original Assignee
Koninklijke Philips Electronics N.V.
Philips Lumileds Lighting Company, Llc
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., Philips Lumileds Lighting Company, Llc filed Critical Koninklijke Philips Electronics N.V.
Publication of WO2009107038A1 publication Critical patent/WO2009107038A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/44—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the coatings, e.g. passivation layer or anti-reflective coating
    • H01L33/46—Reflective coating, e.g. dielectric Bragg reflector
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/48—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
    • H01L33/50—Wavelength conversion elements

Definitions

  • the invention relates to a light emitting diode package comprising a light emitting diode (LED), a color converting medium positioned adjacent to the light emitting diode, and a dome encapsulating both the light emitting diode and the color converting medium.
  • LED light emitting diode
  • Such packages are in particular used in light emitting modules (e.g. luminaries) for illumination purposes.
  • a light emitting diode package of the kind set forth is known from US20070258240. That document discloses a white light generating fixture comprising a multitude of light emitting diode packages. A first package contains a light emitting diode and a first phosphor, while a second package contains a light emitting diode and a second phosphor, so that the two package types are capable of producing light with different spectra.
  • the fixture may comprise a third package having a third phosphor for producing light with a third spectrum. These fixtures can produce any color point in color space within the polygon defined by the packages with the (phosphor facilitated) primary light sources by mixing the appropriate contributions of the primary spectra.
  • CCT adjustable correlated color temperature
  • the CCT ranges from above 4000K (cool white) to about 2700K (warm white).
  • the low correlated color temperatures are difficult to achieve, mostly due to the considerable blue content in the light emitted by phosphor coated LEDs. This blue light originates from the LED itself and has not been used as a pump for the phosphor facilitated color conversion process. In fact, the original blue 'pump' light emitted by the LED and the yellow light emitted by the phosphor forms the white light emitted by the package.
  • US20070258240 discloses the use of filters in the fixture to eliminate a residual blue content in the light emitted by the fixture, thereby lowering the correlated color temperature of that light. Simply filtering out a part of the spectrum emitted clearly constitutes a drawback of the solution described in US20070258240, as it lowers the overall efficiency of the fixture. Moreover, assembling the filters in the luminary forms an uneconomical use of space.
  • the present invention provides a light emitting diode package of the kind set forth which alleviates at least one of the drawbacks.
  • This objective is achieved according to a first aspect of the invention with the light emitting diode package as defined by the preamble of claim 1, wherein the dome is provided with a first filter on its outer surface.
  • the wavelength selective first filter reduces first spectrum (the blue 'pump') light originating from the LED to leak out the package.
  • the first filter induces the light emitted from the package to have a lower correlated color temperature.
  • the first filter is arranged to reflect light having the first spectrum and transmit light having the second spectrum.
  • this allows the blue 'pump' light to be reflected and recycled, i.e. absorbed by the color converting medium and converted into the second spectrum (yellowish/reddish) light.
  • the first filter comprises an interference filter.
  • interference filters do not (in principle) absorb any light.
  • such filters may be tuned to exhibit a maximum reflectance at a wavelength corresponding to the 'pump' light emitted by the LED.
  • the dome substantially forms a half-sphere.
  • the light emitted by the LED and/or color converting medium impinges on the dome surface, and hence on the first filter, nearly perpendicular. This minimises the influence of the angular dependence of interference filters.
  • the interference filter comprises alternating layers of SiO 2 and Ta 2 Os or SiO 2 and TiO 2 .
  • these materials have a ratio of their index of refraction.
  • a high ratio allows making a filter with only a few layers.
  • a high index of refraction reduces the angle of incidence dependence of the filter characteristics.
  • the invention provides a light emitting module comprising at least one light emitting diode package according to the claims 1 to 7.
  • the light emitting module further comprises at least one light source arranged to emit light of at least one of the colors red, green, turquoise, or cyan.
  • this allows producing tuneable white light efficiently with a high color rendering index (> 80) at or around the black body locus.
  • Fig. 1 schematically shows a light emitting diode package.
  • Fig. 2 schematically shows the emission of a typical phosphor coated LED
  • Fig. 3 shows the reflecion spectrum of an example of an interference filter
  • Fig. 4 schematically shows an embodiment of a light emitting diode package
  • Fig. 5 shows a light emitting module
  • FIG. 1 schematically shows a light emitting diode package 1. It comprises a light emitting diode (LED) 10 arranged to emit light having a first spectrum. Furthermore, the package 1 comprises a color converting medium 20 positioned adjacent to the LED 10. Finally, the package 1 comprises a dome 30 encapsulating the LED 10 and the color converting medium 20.
  • the LED 10 may be mounted on a sub-mount allowing connection of the LED to electrical and thermal interfaces (not shown) for providing power to the LED and distribution of dissipated heat, respectively.
  • the color converting medium 20 consists of a phosphor powder deposited on the (top surface of the) LED 10.
  • the phosphor may be dispersed through out the material forming the dome 30.
  • the color converting medium 20 may be applied as a ceramic platelet.
  • the color converting medium 20 converts at least part of the light having the first spectrum 21 (the 'pump' light) into light having a second spectrum 22, usually at longer wavelengths (see Fig. 2).
  • Ce doped YAG phosphors are applied, emitting yellowish light that in combination with the blue 'pump' light creates the impression of white light.
  • Pr or Eu doped phosphors may be used to enhance the red content of the secondary spectrum.
  • the dome 30, having an outer surface 31 usually is made of a transparent epoxy or silicone material and increases the light output from the LED 10, as III-V semiconductor materials have a high index of refraction.
  • the invention provides for a first filter 40 deposited on or positioned adjacent to the outer surface 31 of the dome 30. Integration of the first filter 40 on the dome 30 beneficially makes efficient use of the space available.
  • the first filter 40 comprises an interference filter.
  • These later wavelength selective filters usually comprise a stack of alternating layers with different refractive indices.
  • such interference filters do not (in principle) absorb any light.
  • the interference filter comprises alternating layers of SiO 2 and Ta 2 Os or SiO 2 and TiO 2 . In first order, the periodicity of the stack, i.e.
  • Fig. 3 shows the reflectance as a function of the wavelength for a stack of 15 layers using eight SiO 2 and seven Ta 2 Os layers with optical thicknesses of a ⁇ /4 ⁇ i.e. 111.63 nm * «siO2 and 77.27 nm * /?Ta2O5, respectively).
  • the wavelength at peak reflectivity in this case -650 nm
  • the sum of the optical thicknesses of the two layer types exactly equates ⁇ /2.
  • the filter 3 shows the filter to have a high reflection peak with multiple fringes on each side. Moreover it shows an angular dependence of the filter, i.e. the reflectivity depends on the angle of incidence of the light.
  • the curve 60 characterises the spectral response of the filter for light impinging on it at (near) normal (0°), while curve 70 characterises the spectral response for light impinging at 45°. Adjusting the thicknesses of the individual layers tunes the specific shape of the reflection as a function of the wavelength.
  • the first filter 40 reflects blue ⁇ i.e. the 'pump' light or first spectrum light 21) and transmits green, yellow, and red ⁇ i.e. the second spectrum light 22).
  • Table 1 describes an example of a SiO 2 / Ta 2 Os filter exhibiting these properties. Using more layers increases the specificity of the interference filter, i.e enabling a larger control of the shape of the reflectance curve (f.i. a sharper reflectance peak or steeper flanks).
  • Table 1 SiO 2 / Ta 2 Os layer stack exhibiting a peak reflectivity at about 430 nm.
  • the dome 30 could have any shape (f.i. polygonal, elliptical, spherical, etc), in an embodiment the dome 30 substantially forms a half-sphere.
  • the light emitted by the LED 10 and/or color converting medium 20 impinges on the dome surface 31 , and hence on the first filter 40, nearly perpendicular. This minimises the influence of the angular dependence of interference filters.
  • the light emitting diode package 1 comprises a second filter 50 positioned between the light emitting diode 10 and the color converting medium 20 (Fig. 4).
  • the second filter 50 is arranged to transmit light having the first spectrum 21 and reflect light having the second spectrum 22.
  • this increases the efficiency of the package 1 as reflection of the second spectrum light prevents absorption of that light in the LED 10.
  • the second filter 50 may be deposited on a top surface of the LED before application of a phosphor of ceramic platelet.
  • the second filter 50 may be deposited on the ceramic platelet followed by assembling the platelet on top of the LED 10 such that the second filter 50 is sandwiched between the LED and the platelet.
  • the second filter comprises an interference filter (as described above) tuned to the appropriate response curve.
  • An embodiment provides a light emitting module 100 having a housing 140 and comprising at least one light emitting diode package 1 according to the invention (Fig. 5). This allows providing a luminary or fixture, such as a flood-light or a down-light, suitable for illumination purposes.
  • the light emitting module 100 further comprises at least one light source 110.
  • the light emitting diode packages 1 and light sources 110 may be assembled on a mounting substrate 150.
  • the light sources 110 are arranged to emit red (dominant wavelength ⁇ dom ⁇ 620nm), amber ( ⁇ dom ⁇ 590nm), green ( ⁇ dom ⁇ 530nm), turquoise ( ⁇ dom ⁇ 500nm), or cyan ( ⁇ dom ⁇ 470nm) light.
  • the light emitting module 100 further comprises (programmable) electronics 120 and mixing optics 130 (both well known in the art).
  • a homogeneous tuneable white light can also be made using LEDs with their small bandwidth spectra as primary light sources directly.
  • the invention for recycling this 'pump' light through reflection of a filter 40 on the dome 30 and absorption by the color converting medium 20.
  • a light emitting diode package 1.
  • the package comprises an LED 10, a color converting medium 20, and a dome 30.
  • a filter 40 is applied upon the outer surface 31 of the dome.
  • a light emitting module 100 is proposed comprising at least one light emitting diode package 1. This is especially advantageous for creating homogeneous tuneable white light with a color temperature below 3000K and a color point on or near the black body locus.

Landscapes

  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Power Engineering (AREA)
  • Led Device Packages (AREA)
  • Non-Portable Lighting Devices Or Systems Thereof (AREA)

Abstract

Cette invention se rapporte à un boîtier de diode électroluminescente (1). Le boîtier comprend une DEL (10), un milieu de conversion de couleur (20), et un dôme (30). Un filtre (40) est appliqué sur la surface extérieure (31) du dôme. En outre, l'invention se rapporte à un module électroluminescent (100) qui comprend au moins un boîtier de diode électroluminescente (1). Ceci est particulièrement avantageux pour créer une lumière blanche homogène pouvant être accordée et ayant une température de couleur inférieure à 3000 K et un point de couleur sur le lieu du corps noir, ou à proximité de celui-ci.
PCT/IB2009/050672 2008-02-27 2009-02-19 Boîtier de diode électroluminescente WO2009107038A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP08152018 2008-02-27
EP08152018.1 2008-02-27

Publications (1)

Publication Number Publication Date
WO2009107038A1 true WO2009107038A1 (fr) 2009-09-03

Family

ID=40666946

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB2009/050672 WO2009107038A1 (fr) 2008-02-27 2009-02-19 Boîtier de diode électroluminescente

Country Status (2)

Country Link
TW (1) TW200945634A (fr)
WO (1) WO2009107038A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2472612A1 (fr) * 2010-12-29 2012-07-04 Koninklijke Philips Electronics N.V. Performance de couleur angulaire améliorée de systèmes d'éclairage à DEL blanche
WO2012093765A1 (fr) * 2011-01-07 2012-07-12 Lg Electronics Inc. Appareil d'éclairage et son procédé de commande
WO2013068204A1 (fr) * 2011-11-10 2013-05-16 Osram Opto Semiconductors Gmbh Composant émettant un rayonnement
WO2014060318A1 (fr) * 2012-10-15 2014-04-24 Osram Opto Semiconductors Gmbh Composant émettant un rayonnement
US9612002B2 (en) 2012-10-18 2017-04-04 GE Lighting Solutions, LLC LED lamp with Nd-glass bulb

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3457444A1 (fr) 2017-09-19 2019-03-20 ams AG Dispositif électroluminescent converti au phosphore

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5813752A (en) * 1997-05-27 1998-09-29 Philips Electronics North America Corporation UV/blue LED-phosphor device with short wave pass, long wave pass band pass and peroit filters
US6155699A (en) * 1999-03-15 2000-12-05 Agilent Technologies, Inc. Efficient phosphor-conversion led structure
US20020180351A1 (en) * 2001-04-30 2002-12-05 Mcnulty Thomas Francis UV reflectors and UV-based light sources having reduced UV radiation leakage incorporating the same
DE10142009A1 (de) * 2001-08-28 2003-03-27 Osram Opto Semiconductors Gmbh LED - Lichtquelle
US20040116033A1 (en) * 2003-01-27 2004-06-17 3M Innovative Properties Company Methods of making phosphor based light sources having an interference reflector
US20050127381A1 (en) * 2003-12-10 2005-06-16 Pranciskus Vitta White light emitting device and method
DE102005062514A1 (de) * 2005-09-28 2007-03-29 Osram Opto Semiconductors Gmbh Optoelektronisches Bauelement
WO2007039849A1 (fr) * 2005-10-05 2007-04-12 Philips Intellectual Property & Standards Gmbh Dispositif électroluminescent converti au phosphore avec filtre absorbant
WO2007075393A1 (fr) * 2005-12-20 2007-07-05 Gelcore Llc Ensemble d'éclairage

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5813752A (en) * 1997-05-27 1998-09-29 Philips Electronics North America Corporation UV/blue LED-phosphor device with short wave pass, long wave pass band pass and peroit filters
US6155699A (en) * 1999-03-15 2000-12-05 Agilent Technologies, Inc. Efficient phosphor-conversion led structure
US20020180351A1 (en) * 2001-04-30 2002-12-05 Mcnulty Thomas Francis UV reflectors and UV-based light sources having reduced UV radiation leakage incorporating the same
DE10142009A1 (de) * 2001-08-28 2003-03-27 Osram Opto Semiconductors Gmbh LED - Lichtquelle
US20040116033A1 (en) * 2003-01-27 2004-06-17 3M Innovative Properties Company Methods of making phosphor based light sources having an interference reflector
US20050127381A1 (en) * 2003-12-10 2005-06-16 Pranciskus Vitta White light emitting device and method
DE102005062514A1 (de) * 2005-09-28 2007-03-29 Osram Opto Semiconductors Gmbh Optoelektronisches Bauelement
WO2007039849A1 (fr) * 2005-10-05 2007-04-12 Philips Intellectual Property & Standards Gmbh Dispositif électroluminescent converti au phosphore avec filtre absorbant
WO2007075393A1 (fr) * 2005-12-20 2007-07-05 Gelcore Llc Ensemble d'éclairage

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2472612A1 (fr) * 2010-12-29 2012-07-04 Koninklijke Philips Electronics N.V. Performance de couleur angulaire améliorée de systèmes d'éclairage à DEL blanche
WO2012093765A1 (fr) * 2011-01-07 2012-07-12 Lg Electronics Inc. Appareil d'éclairage et son procédé de commande
WO2013068204A1 (fr) * 2011-11-10 2013-05-16 Osram Opto Semiconductors Gmbh Composant émettant un rayonnement
WO2014060318A1 (fr) * 2012-10-15 2014-04-24 Osram Opto Semiconductors Gmbh Composant émettant un rayonnement
US9500938B2 (en) 2012-10-15 2016-11-22 Osram Opto Semiconductors Gmbh Radiation-emitting component
US9612002B2 (en) 2012-10-18 2017-04-04 GE Lighting Solutions, LLC LED lamp with Nd-glass bulb

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Publication number Publication date
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