Source: http://www.google.com/patents/US20070012940?dq=5,963,646
Timestamp: 2014-09-20 12:36:10
Document Index: 578696927

Matched Legal Cases: ['art 38', 'art 38', 'art 38', 'art 38', 'art 38', 'art 38', 'art 38', 'art 38', 'art 38', 'art 38', 'art 38', 'art 48', 'art 48', 'art 48', 'art 48', 'art 48', 'art 58', 'art 58', 'art 58', 'art 58', 'art 68', 'art 68', 'art 68', 'art 68']

Patent US20070012940 - Wavelength-convertible light emitting diode package - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign in<nobr>Advanced Patent Search</nobr>PatentsThe invention relates to a wavelength-convertible LED package including a package substrate having a lead frame, and an LED mounted on the package substrate and electrically connected to the lead frame. The wavelength-convertible LED package also includes a low refractive index region surrounding the...http://www.google.com/patents/US20070012940?utm_source=gb-gplus-sharePatent US20070012940 - Wavelength-convertible light emitting diode packageAdvanced Patent SearchPublication numberUS20070012940 A1Publication typeApplicationApplication numberUS 11/484,758Publication dateJan 18, 2007Filing dateJul 12, 2006Priority dateJul 14, 2005Publication number11484758, 484758, US 2007/0012940 A1, US 2007/012940 A1, US 20070012940 A1, US 20070012940A1, US 2007012940 A1, US 2007012940A1, US-A1-20070012940, US-A1-2007012940, US2007/0012940A1, US2007/012940A1, US20070012940 A1, US20070012940A1, US2007012940 A1, US2007012940A1InventorsHyo Suh, Hee Park, Masayoshi KoikeOriginal AssigneeSamsung Electro-Mechanics Co., Ltd.Export CitationBiBTeX, EndNote, RefManReferenced by (45), Classifications (15), Legal Events (1) External Links: USPTO, USPTO Assignment, EspacenetWavelength-convertible light emitting diode packageUS 20070012940 A1Abstract The invention relates to a wavelength-convertible LED package including a package substrate having a lead frame, and an LED mounted on the package substrate and electrically connected to the lead frame. The wavelength-convertible LED package also includes a low refractive index region surrounding the LED, having a first refractive index, and a high refractive index layer formed on the low refractive index region, having a rough pattern on an upper surface thereof and a second refractive index higher than the first refractive index. The wavelength-convertible LED package further includes a resin part containing phosphor for converting the wavelength of light emitted from the LED, having a third refractive index lower than the second refractive index. Images(7) Claims(12)
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 3 is a sectional view illustrating a wavelength-convertible LED package according to an embodiment of the present invention. Referring to FIG. 3, the LED package 30 includes a package substrate 31, and a light emitting device 35 mounted on the package substrate 31. The package substrate 31 can be divided into a lower package substrate 31 a with two lead frames 32 a and 32 b, and an upper package substrate 31 b having a cavity therein. The light emitting device 35 is mounted in the cavity. Both electrodes (not shown) of the light emitting device 35 are connected to upper ends of the lead frames 32 a and 32 b by wires. A low refractive index region 36 is provided to surround the light emitting device 35. The low refractive index region 36 can be an empty space but can also be filled with transparent resin having a relatively low refractive index. In case when the low refractive index region 36 is an empty space, it has a refractive index (n=1) similar to that of the atmosphere. In case when the low refractive index region 36 is made of transparent resin, typical epoxy, silicone or mixture thereof can be used. In that case, the low refractive index region 36 may have a refractive index of about 1.7. A high refractive index layer 37 is formed above the low refractive index region 36. The high refractive index layer 37 has a refractive index higher than that of the low refractive index region 36, and has a rough pattern 37 a formed on an upper surface thereof. In addition, a resin part 38 is formed above the high refractive index layer 37. The resin part 38 contains phosphor 39 for converting the wavelength of light emitted from the light emitting device 35. The phosphor-containing resin part 38 has a lower refractive index than the high refractive index layer 37. The high refractive index layer 37 may be made of resin having a high refractive index or made of a typical transparent resin layer containing high refractive index particles. In the latter case, the high refractive index particles may be made of one selected from a group consisting of GaP, Si, TiO2, SrTiO3, SiC, cubic or amorphous carbon, carbon nanotube, AlGaInP, AlGaAs, SiN, SiON, ITO, SiGe, AlN, GaN and mixtures thereof. The high refractive index layer 37 has such a high refractive index that the photons scattered at the phosphor particles are totally reflected at the interface between the high refractive index layer 37 and the low refractive index region 36. It is preferable that the high refractive index layer 37 is formed to have a refractive index of at least 1.8. However, in case of forming the low refractive index region 36 with resin having a specific refractive index, the high refractive index layer 37 can be formed with material having a higher refractive index than the resin of the low refractive index region 36 so that there is a sufficient refractive index difference between the high refractive index layer 37 and the low refractive index region 36. Although the critical angle for light extraction is somewhat small at the interface between the phosphor-containing resin part 38 and the high refractive index layer 37, the rough pattern 37 a formed on the high refractive index layer 37 facilitates light extraction into the phosphor-containing resin part 38. Preferably, convexes of the rough pattern 37 a may have a pitch of about 0.001 to 500 μm. In case when the refractive index difference is too large between the high refractive index layer 37 and the phosphor-containing resin part 38, the rough pattern 37 a may not be effective for sufficient light extraction. Therefore, it is preferable that the high refractive index layer 37 has a refractive index of 10 or lower. FIG. 4 is a schematic view illustrating light extraction mechanism of the LED package shown in FIG. 3. Referring to FIGS. 3 and 4, the light {circumflex over (1)} emitted from the light emitting device 35 passes through the low refractive index region 36 and the high refractive index layer 37 to reach the phosphor-containing resin part 38. Typically, the low refractive index region 36 has a refractive index lower than the nitride constituting the light emitting device 35, but since a rough pattern (not shown) is formed on a surface of the LED, light emitted from the light emitting device 35 can effectively be extracted into the low refractive index region 36. Moreover, the light can be effectively extracted from the low refractive index region 36 into the high refractive index layer 37 because in this case, light is propagating from the low refractive index material to the high refractive index material. The phosphor-containing resin part has a lower refractive index than the high refractive index layer, thus having a limited critical angle for light extraction, but light can still be effectively extracted due to the rough pattern formed on an upper surface of the high refractive index layer. The emission light {circle around (1)} of the LED collides into the phosphor particle 39, producing excited light, and a portion {circle around (2)} of the excited light can be extracted into a desired direction, i.e., the upper part of the package. On the other hand, other portion {circle around (3)} of the excited light is bound inward of the package to propagate from the phosphor-containing resin part 38 to the high refractive index layer 37. Since the phosphor-containing resin part 38 has a lower refractive index than the high refractive index layer 37, the light {circle around (3)} bound inward of the package can enter the high refractive index layer 37 with almost no loss. Most of the light {circle around (3)} that enters the high refractive index layer 37 is totally reflected by high refractive index difference at the interface between the low refractive index region 36 and the high refractive index layer 37. The totally reflected light {circle around (4)} propagates to the upper part of the high refractive index layer 37, and passes through the interface between the high refractive index layer 37 and the phosphor-containing resin part 38 to be extracted into a desired direction. As explained herein above, although the critical angle for light extraction is limited at the interface between the high refractive index layer 37 and the phosphor-containing resin part 38, the rough pattern 37 a formed on an upper surface of the high refractive index layer 37 facilitates light extraction. Therefore, the light {circle around (3)} that is scattered by the phosphor particles 39 to propagate inside the package can effectively be totally reflected in a desired upward direction by the high refractive index layer 37 with the rough patterned formed thereon and the low refractive index region 36. The present invention adopts an optical structure in which a resin part containing phosphor particles is disposed above an optical structure with a high refractive index layer having a rough pattern and a low refractive index region. Thus, light scattered omni directionally at the phosphor particles can be adjusted to propagate upward, thereby improving light extraction efficiency. The present invention can be modified in various forms while maintaining distinctive constituents described above. FIGS. 5(a) and 5(b) are sectional views illustrating wavelength-convertible LED packages according to another embodiment of the invention. FIG. 5(a) illustrates a structure with an improved phosphor-containing resin part, and FIG. 5(b) illustrates a structure with a modified package substrate. The LED package 40 shown in FIG. 5(a) includes a package substrate 41 and a light emitting device 45 mounted on the package substrate 41, similar to the LED package shown in FIG. 3. The package substrate 41 is composed of a lower package substrate 41 a with two lead frames 42 a and 42 b formed thereon and an upper package substrate 41 b having a cavity therein. Both electrodes (not shown) of the light emitting device 45 are connected respectively to the lead frames 42 a and 42 b by wires. A low refractive index region 46 is provided to surround the light emitting device 45. The low refractive index region 46 can be an empty space or can be filled with epoxy or silicone resin having a relatively low refractive index. Alternatively, the low refractive index region 46 can be formed as an empty space while a lens (not shown) made of resin of low refractive index can be disposed to surround the light emitting device 45 in the empty space. A high refractive index layer 47 is formed above the low refractive index region 46. The high refractive index layer 47 has a higher refractive index than the low refractive index region 46, and has a rough pattern 47 a formed on an upper surface thereof. The rough pattern 47 a formed on the high refractive index layer 47 can facilitate light extraction into a phosphor-containing resin part 48 which has a relatively low refractive index. Preferably, convexes of the rough pattern 47 a have a pitch of about 0.001 to 500 μm. According to this embodiment, an anti-reflective layer 47 b can additionally be formed on a lower surface of the high refractive index layer 47, i.e., the interface between the high refractive index layer 47 and the low refractive index region 46. The anti-reflective layer 47 b is made of material having anti-reflectivity in the wavelength band of the light emitting device 45, and can facilitate propagation of light emitted from the light emitting device 45 to the high refractive index layer 47. A resin part 48 containing phosphor 49 is formed above the high refractive index layer 47 to convert the wavelength of light emitted from the light emitting device 45. The phosphor-containing resin layer 48 has a lower refractive index than the high refractive index layer 47. In this embodiment, the phosphor-containing resin part 48 is formed by a typical method in which a transparent resin is formed and phosphor 49 is dispersed on an upper surface thereof. Similar to other embodiments, the layer made of phosphor particles 49 is disposed above an optical structure composed of a high refractive index layer 47 and a low refractive index region 46. Thus, improved light extraction efficiency according to the present invention is also expected from this embodiment. In addition, the high refractive index layer 47 can be made of resin having a high refractive index or typical transparent resin containing high refractive index particles. It is preferable that the high refractive index layer 47 has a refractive index of at least 1.8 to allow total reflection of the photons scattered at the phosphor particles 49 at the interface between the high refractive index layer 47 and the low refractive index region 46, and up to 10 to facilitate light extraction into the phosphor-containing rein part 48. According to this embodiment, in case of forming the low refractive index region 46 with epoxy or silicone resin, the high refractive index layer 47 and the phosphor-containing resin part 48 can be formed by applying and curing continuously, which however does not limit the manufacturing process of the package of the present invention. The rough pattern 47 a formed on the high refractive index layer 47 can be formed by mechanical or chemical etching after the curing process or formed by a molding frame before the curing process. The LED package illustrated in FIG. 5(b) includes a package substrate 51 and a light emitting device 55 mounted on the package substrate 51. The package substrate 51 includes two lead frames 52 a and 52 b on upper surfaces thereof, two connection pads 54 a and 54 b on lower surfaces thereof and conductive vias 53 a and 53 b connecting each of the lead frames with each of the connection pads, which however does not limit the present invention. Similar to other embodiments, the LED package 50 includes a hemispheric low refractive index region 56 around a light emitting device 55, a high refractive index layer 57 formed to surround the low refractive index region 56, and a phosphor-containing resin part 58 formed above the high refractive index layer 57. The high refractive index layer 57 has a higher refractive index than the low refractive index region 56, and has a rough pattern 57 a formed on an upper surface thereof. The phosphor-containing resin part 58 has a lower refractive index than the high refractive index layer 57. According to this embodiment, the hemispheric low refractive index region 56 can be easily formed with transparent resin part using conventional molding processes such as transfer molding. In that case, other layers 57 and 58 can also be formed by similar molding processes. Alternatively, in case of providing the low refractive index region 56 as an empty space, the high refractive index layer 57 and/or the phosphor-containing resin part 58 can be manufactured into a desired shape in a separate molding process (e.g. transfer molding), and then attached to the package substrate 51. The high refractive index layer 57 and the phosphor-containing resin part 58 are exemplified by a hemispheric shape but can be formed in various shapes such as those having a rectangular or triangular cross-section. The variety in shapes can be applied also to the structure in FIG. 5(a). In the embodiment shown in FIG. 5(a), the high refractive index layer 47 has a planar shape but can be modified to have a hemispheric shape similar to that in FIG. 5(b) or other shapes. The high refractive index layer adopted in the invention can be formed in various shapes. In particular, the rough pattern does not have to be formed by typical molding or etching processes but can be formed only by the peculiar shape of high refractive index particles, which is illustrated in FIG. 6. Referring to FIG. 6, similar to the embodiment shown in FIG. 3, the LED package 60 includes a package substrate 61 and a light emitting device 65 mounted on the package substrate 61. The package substrate 61 can be composed of a lower package substrate 61 a with two lead frames 62 a and 62 b formed thereon and an upper package substrate 61 b with a cavity therein. A light emitting device 65 is mounted in the cavity. Both electrodes (not shown) of the light emitting device 65 are connected respectively to upper ends of the lead frames 62 a and 62 b by wires. A low refractive index region 66 is provided to surround the light emitting device 65. The low refractive index region 66 can be an empty space or can be filled with transparent resin having relatively low refractive index. In case when the low refractive index region 66 is an empty space, it has a refractive index (n=1) similar to that of the atmosphere. In addition, in case when the low refractive index region 66 is formed with transparent resin, typical epoxy, silicone or mixture thereof can be used. In that case, the low refractive index region 66 can have a refractive index of about 1.7. A high refractive index layer 67 is formed above the low refractive index region 66. The high refractive index layer 67 is made of high refractive index particles having a refractive index higher than the low refractive index region 66, and a rough pattern 67 a thereon is formed with the particles. Therefore, the shape or pitch of the rough pattern 67 a is determined by the diameter or shapes of the high refractive index particles. The high refractive index particles may be made of one selected from a group consisting of GaP, Si, TiO2, SrTiO3, SiC, cubic or amorphous carbon, carbon nanotube, AlGaInP, AlGaAs, SiN, SiON, ITO, SiGe, AlN, GaN and mixtures thereof. The high refractive index layer 67 can be formed in a separate process as a film structure with the high refractive index particles disposed at least on the upper surface thereof, and then can be placed in the cavity. Alternatively, in case when the low refractive index region 66 is formed with a specific resin, the high refractive index particles can be densely dispersed on the upper surface of the resin to form the high refractive index layer 67. A resin part 68 containing phosphor 69 is formed above the high refractive index layer 67 to convert the wavelength of light emitted from the light emitting device 65. The phosphor-containing resin part 68 has a lower refractive index than the high refractive index layer 67. The rough pattern 67 a formed on the high refractive index layer 67 facilitates light extraction into the phosphor-containing resin part 68 which has a relatively low refractive index. In case when the refractive index difference is too large between the high refractive index layer 67 and the phosphor-containing resin part 68, the rough pattern 67 a may not be effective for sufficient light extraction. Therefore, it is preferable that the high refractive index layer 67 has a refractive index of up to 10. According to the present invention as set forth above, a phosphor-containing resin part is disposed above a new optical structure utilizing different refractive indices and a rough pattern, thereby effectively re-extract light, into a desired direction, which is scattered by phosphor particles and propagates inside the package. Consequently, the invention provides a wavelength-convertible LED having excellent light extraction efficiency. While the present invention has been shown and described in connection with the preferred embodiments, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the spirit and scope of the invention as defined by the appended claims. Referenced byCiting PatentFiling datePublication dateApplicantTitleUS7503676 *Jul 26, 2007Mar 17, 2009Kyocera CorporationLight-emitting device and illuminating apparatusUS7595549 *Jan 20, 2006Sep 29, 2009Stanley Electric Co., Ltd.Surface mount semiconductor deviceUS7795055 *Jan 10, 2008Sep 14, 2010Samsung Led Co., Ltd.Method of manufacturing light emitting diode packageUS7812362 *Apr 14, 2008Oct 12, 2010Samsung Led Co., Ltd.White light emitting diode and method of manufacturing the sameUS7893453 *Dec 2, 2008Feb 22, 2011Stanley Electric Co., Ltd.LED device and method for manufacturing the sameUS7897989Nov 21, 2007Mar 1, 2011E&E Japan Co., Ltd.Light emitterUS7915085Sep 18, 2003Mar 29, 2011Cree, Inc.Molded chip fabrication methodUS7943952Jul 27, 2007May 17, 2011Cree, Inc.Method of uniform phosphor chip coating and LED package fabricated using methodUS7955879Feb 24, 2009Jun 7, 2011Samsung Electronics Co., Ltd.Method of forming LED semiconductor device having annealed encapsulant layer and annealed luminescence conversion material layerUS8033707Oct 17, 2008Oct 11, 2011Lg Display Co., Ltd.LED backlight assembly having lower brightness LEDs at endsUS8130803Sep 4, 2008Mar 6, 2012Kabushiki Kaisha ToshibaLight emitting deviceUS8324797 *Feb 14, 2008Dec 4, 2012Samsung Electronics Co., Ltd.White light emitting diode and method of manufacturing the sameUS8368101Jan 23, 2008Feb 5, 2013Osram Opto Semiconductors GmbhArrangement for generating mixed light and method for producing such an arrangementUS8390189Jan 20, 2012Mar 5, 2013Samsung Electronics Co., Ltd.White light emitting diode and method of manufacturing the sameUS8419229Jan 31, 2011Apr 16, 2013Everlight Electronics Co., Ltd.Electronic device and lighting unit thereofUS8434883Dec 28, 2011May 7, 2013SemiOptoelectronics Co., Ltd.LLB bulb having light extracting rough surface pattern (LERSP) and method of fabricationUS8445932 *Mar 6, 2012May 21, 2013Radiant Opto-Electronics CorporationLight-emitting diode deviceUS8461607 *Dec 28, 2010Jun 11, 2013Hon Hai Precision Industry Co., Ltd.Light emitting diode packageUS8519426Aug 9, 2011Aug 27, 2013Lg Innotek Co., Ltd.Light emitting device and lighting system having the sameUS8637883 *Mar 19, 2008Jan 28, 2014Cree, Inc.Low index spacer layer in LED devicesUS8690395May 27, 2010Apr 8, 2014Koninklijke Philips Electronics N.V.Efficient light emitting device and method for manufacturing such a deviceUS8692270 *Jul 23, 2007Apr 8, 2014Epistar CorporationLight emitting deviceUS8754440 *Mar 22, 2011Jun 17, 2014Tsmc Solid State Lighting Ltd.Light-emitting diode (LED) package systems and methods of making the sameUS20080224160 *Dec 21, 2007Sep 18, 2008Samsung Electro-Mechanics Co., Ltd.High-power light emitting diode and method of manufacturing the sameUS20080283864 *May 16, 2007Nov 20, 2008Letoquin Ronan PSingle Crystal Phosphor Light Conversion Structures for Light Emitting DevicesUS20090236621 *Mar 19, 2008Sep 24, 2009Cree, Inc.Low index spacer layer in LED devicesUS20110079816 *Oct 6, 2010Apr 7, 2011Nitto Denko CorporationOptical-semiconductor encapsulating materialUS20110095319 *Oct 21, 2010Apr 28, 2011Sun Kyung KimLight emitting device package, lighting module and lighting systemUS20120086035 *Nov 23, 2011Apr 12, 2012SemiLEDs Optoelectronics Co., Ltd.LED Device With A Light Extracting Rough Structure And Manufacturing Methods ThereofUS20120098000 *Dec 28, 2010Apr 26, 2012Hon Hai Precision Industry Co., Ltd.Light emitting diode packageUS20120098017 *Mar 11, 2010Apr 26, 2012Koito Manufacturing Co., Ltd.Light emitting module, method of producing light-emitting module, and lighting fixture unitUS20120134152 *Nov 23, 2011May 31, 2012Ye Zhi-TingLight source for crystal lampUS20120138981 *Dec 2, 2010Jun 7, 2012Chung-Shan Institute of Science and Technology, Armaments, Bureau, Ministry of National DefenseLight-Emitting Diode Apparatus and Method for Making the SameUS20120241784 *Mar 22, 2011Sep 27, 2012Taiwan Semiconductor Manufacturing Companty, Ltd.Light-emitting diode (led) package systems and methods of making the sameUS20130193837 *Jan 24, 2013Aug 1, 2013Sharp Kabushiki KaishaPhosphor plate, light emitting device and method for manufacturing phosphor plateUS20130207141 *Feb 13, 2012Aug 15, 2013Cree, Inc.Lighting device including multiple encapsulant material layersDE102011009369A1 *Jan 25, 2011Jul 26, 2012Osram Opto Semiconductors GmbhOptoelektronischer Halbleiterchip und Verfahren zu dessen HerstellungEP2312625A2 *Oct 6, 2010Apr 20, 2011Nitto Denko CorporationOptical-semiconductor encapsulating materialEP2334149A2 *Sep 25, 2009Jun 15, 2011LG Chem, Ltd.Organic light-emitting diodes (oleds) with high efficiency and its manufacturing methodWO2008089740A1 *Jan 23, 2008Jul 31, 2008Osram Opto Semiconductors GmbhArrangement for generating mixed light, and method for the production of such an arrangementWO2009117067A1Mar 11, 2009Sep 24, 2009Cree, Inc.Low index spacer layer in led devicesWO2010143093A1 *May 27, 2010Dec 16, 2010Koninklijke Philips Electronics N.V.Efficient light emitting device and method for manufacturing such a deviceWO2011015959A1 *Jul 7, 2010Feb 10, 2011Philips Lumileds Lighting Company, LlcLed with silicone layer and laminated remote phosphor layerWO2012113181A1 *May 19, 2011Aug 30, 2012Hong Kong Applied Science And Technology Research Institute Co., Ltd.Led package for uniform color emissionWO2013032766A2 *Aug 20, 2012Mar 7, 2013Micron Technology, Inc.Solid-state radiation transducer devices having flip-chip mounted solid-state radiation transducers and associated systems and methods* Cited by examinerClassifications U.S. Classification257/99, 257/E33.074, 257/E33.059International ClassificationH01L33/62, H01L33/54, H01L33/56, H01L33/50, H01L33/22Cooperative ClassificationH01L2224/48091, H01L33/56, H01L2933/0091, H01L33/44, H01L33/507European ClassificationH01L33/50D, H01L33/56Legal EventsDateCodeEventDescriptionJul 12, 2006ASAssignmentOwner name: SAMSUNG ELECTRO-MECHANICS CO., LTD., KOREA, REPUBLFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SUH, HYO WON;PARK, HEE SEOK;KOIKE, MASAYOSHI;REEL/FRAME:018055/0128Effective date: 20060619RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google