Source: http://www.google.com/patents/US20030151361?ie=ISO-8859-1&dq=7,339,580
Timestamp: 2014-07-30 15:40:51
Document Index: 306986277

Matched Legal Cases: ['art 30', 'art 30', 'art 30', 'art 30', 'art 30', 'art 30', 'art 30', 'art 30', 'art 30']

Patent US20030151361 - Light emitting diode - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign in<nobr>Advanced Patent Search</nobr>PatentsDisclosed is a light emitting diode capable of accomplishing enlargement of emitted range of light and equalization of brightness of emitted light. The light emitting diode comprises a substrate (22), electrodes (23 a, 23 b), a light emitting element (24) mounted on the substrate (22) and connected electrically...http://www.google.com/patents/US20030151361?utm_source=gb-gplus-sharePatent US20030151361 - Light emitting diodeAdvanced Patent SearchPublication numberUS20030151361 A1Publication typeApplicationApplication numberUS 10/360,922Publication dateAug 14, 2003Filing dateFeb 10, 2003Priority dateFeb 8, 2002Also published asUS7193365Publication number10360922, 360922, US 2003/0151361 A1, US 2003/151361 A1, US 20030151361 A1, US 20030151361A1, US 2003151361 A1, US 2003151361A1, US-A1-20030151361, US-A1-2003151361, US2003/0151361A1, US2003/151361A1, US20030151361 A1, US20030151361A1, US2003151361 A1, US2003151361A1InventorsMitsunori IshizakaOriginal AssigneeCitizen Electronics Co., Ltd.Export CitationBiBTeX, EndNote, RefManReferenced by (26), Classifications (19), Legal Events (2) External Links: USPTO, USPTO Assignment, EspacenetLight emitting diodeUS 20030151361 A1Abstract Disclosed is a light emitting diode capable of accomplishing enlargement of emitted range of light and equalization of brightness of emitted light. The light emitting diode comprises a substrate (22), electrodes (23 a, 23 b), a light emitting element (24) mounted on the substrate (22) and connected electrically with the electrodes (23 a, 23 b), a resinous cover (26) for sealing the light emitting element (24) and electrodes (23 a, 23 b) and an uneven shaped light scattering part (30) provided on a surface of the cover. Images(6) Claims(12)
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0032] Referring to FIG. 1, one embodiment of a light emitting diode according to the present invention is shown. [0033] The light emitting diode 21 in the embodiment comprises a substrate 22 made of glass epoxy, BT resin (bismaleimide triazine resin) or the like, a pair of electrodes 23 a and 23 b mounted on the substrate 22, a light emitting element 24 mounted on the substrate 22, bonding wires 25 for connecting electrically the light emitting element 24 and electrodes 23 a and 23 b, and a cover 26 for sealing the light emitting element 24, electrodes 23 a and 23 b and at least connecting portions between the electrodes and bonding wires. [0034] In this way, covering the light emitting element 24, electrodes 23 a and 23 b, bonding wires 25 and so on by the cover 26 causes the portions covered by the cover to prevent from corroding. [0035] Note that the electrodes 23 a and 23 b may be mounted on an outside substrate of a mother board (not shown) and so on. [0036] The light emitting element 24 may be formed from, for example, a square micro silicon chip. The light emitting element is fixed at its bottom on the substrate 22 by means of an insulating adhesive 28. For example, an upper surface of the light emitting element 24 is provided with a pair of electrodes 29 a and 29 b (anode and cathode electrodes). [0037] One of the bonding wires 25 is connected at one end to the electrode 29 a of the element 24 and at the other end to the electrode 23 a mounted on the substrate 22. The other bonding wire is connected at one end to the electrode 29 b of the element 24 and at the other end to the electrode 23 b mounted on the substrate 22. [0038] The cover 26 is formed from a three dimensional sealing body attached on the substrate 22 centering on the light emitting element 24. [0039] In one embodiment, the cover 26 is consisted by forming a material of epoxy resin having permeability by means of a molding. [0040] In this case, the molding, for example, has a pair of U-shaped side mold pieces 41,41 for forming a space 40 corresponding to a prepared shape of the cover 26 and an upper mold piece 42 disposed at an upper surface of the mold pieces 41,41 as shown in FIG. 4. [0041] The pair of side mold pieces 41, 41 are first disposed on the substrate 22 after the light emitting element 24, electrodes 23 a, 23 b and bonding wires 25 are mounted on the substrate as described above and as shown in FIG. 1 and then a predetermined amount of liquid epoxy resin is poured into the space 40 surrounded by the pair of side mold pieces and then the upper mold piece 42 is mounted on the side mold pieces. [0042] After a predetermined time is elapsed, in other words, when the epoxy resin is hardened, the side and upper mold pieces are removed in order to form the cover 26 as shown in FIG. 1. Because the cover has permeability of light, light emitted from the light emitting element 24 passes through the cover and then is emitted from surfaces of the cover to outside of the cover as scattered light. [0043] As the other method for producing the cover using a molding, for example, there is a case of forming together a great number of light emitting diodes on one substrate. In this case, the substrate is first surrounded with the molding and then the great number of light emitting diodes are arranged on the substrate and then each light emitting diode and electrodes provided on the substrate are connected by the bonding wires. Liquid epoxy resin is poured from the above of the substrate in a space surrounded by the molding. After the epoxy resin is hardened, the molding is removed from a product formed by the resin. Finally, the product is separated in individual light emitting diode by dicing every the light emitting diode in x and y directions of the product. [0044] It should be noted in the present invention that light scattering means is provided on the cover 26. The light scattering means is composed of an uneven light scattering part 30 formed on at least one surface of the cover, for example, on an upper surface, namely, on a light emitting projected surface 27 of the cover 26 facing to the upper surface of the light emitting element 24, in the shown embodiment. [0045] Concretely, the light scattering part is composed of a configuration that a large number of concave and convex portions 31 and 32 are alternately arranged in one embodiment. These concave and convex portions are provided on, for example, the entire region of the light emitting projected surface 27. Size and arrangement of the concave and convex portions, oblique angle of circumferential walls forming the concave and convex portions and so on may be set adequately according to a degree of scattering of light emitted from the cover 26 toward the outside thereof. [0046] As described above, light emitted toward the above from the light emitting element 24 is scattered widely toward the outside of the cover at the emitted surface of the cover having the large number of concave and convex portions by function of the concave and convex portions, more specifically, based on the oblique angle of the circumferential walls. [0047] When the cover 26 is formed by a molding, the a shape of the concave and convex portions in the light scattering part 30 is formed by carrying out etching on the upper surface of the cover 26 which is in semi-hardened state or by pressing a processing jig which has concave and convex patterns to form the concave and convex portions on the upper surface of the cover 26. Further, after the cover 26 is hardened completely, the concave and convex portions having a predetermined depth or oblique angle may be formed by machining the upper surface of the cover, for example, cutting. [0048] The depth and oblique angle of each of their concave and convex portions consisting the light scattering part 30 are determined in accordance with an object of using and a specification of emitting light for the light emitting diode 21 while it is preferable to increase the depth of the concave and convex portions in order to increase the scattering of light. [0049] In this embodiment, it is possible to obtain a large light scattering effect by setting in such a manner that the depth of the concave and convex portions is more than 4 μm and the oblique angle is in a range of 1�45 degrees in case of the thickness of 400 μm of the cover 26. [0050] It is recognized that the depth and oblique angle of each of the concave and convex portions in the light scattering part 30 are un-uniform and with a degree of unevenness, a large light scattering effect is obtained since the reflection and refraction of light become irregular. [0051] Next, an operation of emitting light of the light emitting diode 21 as constructed in the above will be explained in connection with FIG. 2. [0052] As well known, the light emitting diode 21 emits light by the electrodes 23 a and 23 b mounted on the substrate 22 being powered on and by the light emitting element 24 being excited. [0053] The emitted light goes through the cover to the light emitting projected surface 27 of the cover 26 facing to the light emitting element 24 and further is refracted at the uneven light scattering part 30 formed on the light emitting projected surface 27 and the refracted light is scattered with many angles to the outside of the cover. [0054] Such refraction of light varies according to the depth or oblique of the concave and convex portions to emit not only from the upper surface of the cover 26 and to emit but also from a side surface of the cover 26 with large refraction. There is also a case that after the light emitted from the light emitting element 24 is reflected on the light scattering part 30 and then is reflected within the cover 26 to finally emit from the cover to the outside thereof. [0055] Because the refraction and reflection of light are generated continuously within the cover and at the outer surface (s) of the cover, there is no difference between brightness in case of looking at the light emitting projected surface 27 from the right above and brightness in case of looking at the light emitting projected surface 27 from a deviated position which is sideward obliquely of the surface. [0056] Accordingly, it is possible to obtain a wide range of light scattering and high brightness as a whole of the cover. [0057]FIG. 3 illustrates an example of a structure in which the light scattering part 30 is formed by printing. [0058] The light emitting diode 31 according to this embodiment has a film 32 printed on the light emitting projected surface 27 of the cover 26 for sealing the light emitting element 24. The film is made of, for example, a resin and has at one surface concave and convex portions for scattering light. Alternatively, after a thin sheet is printed on the light emitting projected surface 27, the concave and convex portions may be formed on the sheet to make the aforementioned film. [0059] Shape, depth and so on of the concave and convex portions in the embodiment may be similarly set as that of the light emitting diode 21 as shown in FIGS. 1 and 2. [0060] It is also preferable that the same transparent epoxy resin material as that of the cover 26 is used in the film not to lose permeability of light. [0061] Other than the methods shown in FIGS. 1 and 2, the uneven light scattering part 30 can be formed simultaneously with forming of the cover 26 by pre-forming concave and convex surfaces in an inner wall of a molding used in forming the cover 26. For example, if the concave and convex portions are formed on the back surface of the upper mold piece 42 as shown in FIG. 4, it is possible to form the concave and convex portions on a surface of the cover to make the light scattering part when the cover is formed. [0062] According to this formation, it is possible to use adequately and selectively a molding according to a specification of a light emitting diode to be produced by use of prepared several kinds of moldings having different shapes of the concave and convex portions. [0063] In such a case, the uneven light scattering part can be formed by a conventional resin forming proves and therefore a light emitting diode in which light is widely emitted can be produced inexpensively without increasing number of process. [0064] Further, the light scattering part may be composed of a frosted glass (not shown) attached on one surface of the cover 26. [0065] Although the light scattering part 30 is disposed on the light emitting projected surface 27 laying at the upper surface of the cover 26 in the aforementioned embodiment, the similar light scattering part may be provided on one or more side surfaces of the cover 26 and further if the light emitting projected surface is provided on a side surface of the cover 26, the light scattering part may be formed only on the light emitting projected surface. [0066] In the embodiments as described above, although the electrodes 23 a and 23 b mounted on the substrate 22 and the light emitting element 24 are connected by the bonding wires 25, alternatively, it is possible to connect the electrodes and light emitting element by a flip-chip mounting method in which a soldered bump which is formed on the lower surface of the light emitting element 24 is connected directly with the electrodes 23 a and 23 b. [0067] As described above, according to the light emitting diode in the present invention, since the uneven light scattering part is provided on the surface of the cover for sealing the light emitting element, light emitted from the light emitting element can be largely refracted at the light scattering part to cause the light to scatter widely. Other than emitting the light from the light emitting element to the outside of the cover, a scattering phenomenon is occurred within the cover by light reflected on the inside of the cover to equalize the emitted light and to enhance entire brightness of the emitted light. It is therefore possible to emit uniformly in all direction without dispersion of the emitted light in accordance with an angle of looking at the light emitting diode. [0068] The light scattering part can also be formed easily by means of a process of rough surface by etching or cutting out of the surface of the cover. As a result, it is possible to produce inexpensively by a small number of processes. Referenced byCiting PatentFiling datePublication dateApplicantTitleUS7290902 *Apr 14, 2005Nov 6, 2007Nitto Denko CorporationDirect-type backlightUS7293889 *Dec 16, 2004Nov 13, 2007Toyoda Gosei Co., Ltd.LED lamp apparatusUS7294861Jun 30, 2005Nov 13, 20073M Innovative Properties CompanyPhosphor tape articleUS7414270 *Mar 8, 2006Aug 19, 2008Samsung Electro-Mechanics Co., Ltd.Side-emitting LED package having scattering area and backlight apparatus incorporating the LED lensUS7598533 *May 2, 2006Oct 6, 2009Industrial Technology Research InstituteHigh heat dissipating LED having a porous material layerUS7655486Apr 30, 2007Feb 2, 20103M Innovative Properties CompanyMethod of making light emitting device with multilayer silicon-containing encapsulantUS7897989Nov 21, 2007Mar 1, 2011E&E Japan Co., Ltd.Light emitterUS8034647 *Jun 22, 2010Oct 11, 2011Cree, Inc.LED with substrate modifications for enhanced light extraction and method of making sameUS8044585 *May 2, 2006Oct 25, 2011Chain Technology Consultant Inc.Light emitting diode with bumpsUS8092053 *May 13, 2010Jan 10, 2012Harold Phillip KoppLight fixture assembly and method of manufactureUS8329482Apr 30, 2010Dec 11, 2012Cree, Inc.White-emitting LED chips and method for making sameUS8362512Dec 11, 2009Jan 29, 2013Cree, Inc.Side-view surface mount white LEDUS8390022Jan 10, 2012Mar 5, 2013Cree, Inc.Side view surface mount LEDUS8434883Dec 28, 2011May 7, 2013SemiOptoelectronics Co., Ltd.LLB bulb having light extracting rough surface pattern (LERSP) and method of fabricationUS8487337Mar 14, 2011Jul 16, 2013Cree, Inc.Side view surface mount LEDUS8545082Jul 9, 2010Oct 1, 2013Lg Innotek Co., Ltd.Light emitting apparatus and lighting systemUS8552444 *Nov 13, 2008Oct 8, 2013Panasonic CorporationSemiconductor light-emitting device and manufacturing method of the sameUS8557617Feb 22, 2007Oct 15, 2013Samsung Electronics Co., Ltd.Method of manufacturing light emitting diode packageUS8604497Sep 26, 2003Dec 10, 2013Osram Opto Semiconductors GmbhRadiation-emitting thin-film semiconductor chipUS8617909Apr 1, 2009Dec 31, 2013Cree, Inc.LED with substrate modifications for enhanced light extraction and method of making sameUS20100258830 *Nov 13, 2008Oct 14, 2010Yoshiyuki IdeSemiconductor light-emitting device and manufacturing method of the sameUS20120086035 *Nov 23, 2011Apr 12, 2012SemiLEDs Optoelectronics Co., Ltd.LED Device With A Light Extracting Rough Structure And Manufacturing Methods ThereofCN100385315CApr 21, 2005Apr 30, 2008日东电工株式会社Direct-type backlightEP2071642A2 *Dec 2, 2008Jun 17, 2009Cree, Inc.Textured encapsulant surface in led packagesEP2151873A2 *Jul 5, 2005Feb 10, 2010Cree, Inc.Solid metal block semiconductor light emitting device mounting substrates and packagesWO2006091327A1 *Jan 26, 2006Aug 31, 20063M Innovative Properties CoMethod of making led encapsulant with undulating surface* Cited by examinerClassifications U.S. Classification313/512, 257/E33.074, 257/E33.059International ClassificationH01L33/54, H01L33/56, H01L33/22Cooperative ClassificationH01L2224/32225, H01L2924/1815, H01L2924/12041, H01L2224/48091, H01L2224/32245, H01L33/54, H01L2224/48227, H01L2933/0091, H01L33/44, H01L2224/73265, H01L2924/10253European ClassificationH01L33/44, H01L33/54Legal EventsDateCodeEventDescriptionJun 3, 2010FPAYFee paymentYear of fee payment: 4Apr 9, 2003ASAssignmentOwner name: CITIZEN ELECTRONICS CO., LTD., JAPANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:ISHIZAKA, MITSUNORI;REEL/FRAME:013938/0719Effective date: 20030120RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google