WO2004019422A1 - White light emitting device - Google Patents

White light emitting device Download PDF

Info

Publication number
WO2004019422A1
WO2004019422A1 PCT/KR2002/002240 KR0202240W WO2004019422A1 WO 2004019422 A1 WO2004019422 A1 WO 2004019422A1 KR 0202240 W KR0202240 W KR 0202240W WO 2004019422 A1 WO2004019422 A1 WO 2004019422A1
Authority
WO
WIPO (PCT)
Prior art keywords
light emitting
emitting device
white light
corpuscles
phosphors
Prior art date
Application number
PCT/KR2002/002240
Other languages
French (fr)
Inventor
Jae-Soo Yoo
Kwan-Young Han
Original Assignee
Seoul Semiconductor Co., Ltd.
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
Priority claimed from KR1020020066353A external-priority patent/KR100554453B1/en
Application filed by Seoul Semiconductor Co., Ltd. filed Critical Seoul Semiconductor Co., Ltd.
Priority to AU2002368183A priority Critical patent/AU2002368183A1/en
Publication of WO2004019422A1 publication Critical patent/WO2004019422A1/en

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers 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 having potential barriers 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
    • H01L33/501—Wavelength conversion elements characterised by the materials, e.g. binder
    • H01L33/502—Wavelength conversion materials
    • H01L33/504—Elements with two or more wavelength conversion materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/26—Layer connectors, e.g. plate connectors, solder or adhesive layers; Manufacturing methods related thereto
    • H01L2224/31—Structure, shape, material or disposition of the layer connectors after the connecting process
    • H01L2224/32—Structure, shape, material or disposition of the layer connectors after the connecting process of an individual layer connector
    • H01L2224/321—Disposition
    • H01L2224/32151—Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/32221—Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/32245—Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/26—Layer connectors, e.g. plate connectors, solder or adhesive layers; Manufacturing methods related thereto
    • H01L2224/31—Structure, shape, material or disposition of the layer connectors after the connecting process
    • H01L2224/32—Structure, shape, material or disposition of the layer connectors after the connecting process of an individual layer connector
    • H01L2224/321—Disposition
    • H01L2224/32151—Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/32221—Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/32245—Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic
    • H01L2224/32257—Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic the layer connector connecting to a bonding area disposed in a recess of the surface of the item
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/4805—Shape
    • H01L2224/4809—Loop shape
    • H01L2224/48091—Arched
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/481—Disposition
    • H01L2224/48151—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/48221—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/48245—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic
    • H01L2224/48247—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic connecting the wire to a bond pad of the item
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/73—Means for bonding being of different types provided for in two or more of groups H01L2224/10, H01L2224/18, H01L2224/26, H01L2224/34, H01L2224/42, H01L2224/50, H01L2224/63, H01L2224/71
    • H01L2224/732—Location after the connecting process
    • H01L2224/73251—Location after the connecting process on different surfaces
    • H01L2224/73265—Layer and wire connectors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2933/00—Details relating to devices covered by the group H01L33/00 but not provided for in its subgroups
    • H01L2933/0091—Scattering means in or on the semiconductor body or semiconductor body package
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers 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 having potential barriers 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
    • H01L33/501—Wavelength conversion elements characterised by the materials, e.g. binder
    • H01L33/502—Wavelength conversion materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers 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 having potential barriers 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
    • H01L33/52—Encapsulations
    • H01L33/56—Materials, e.g. epoxy or silicone resin

Definitions

  • the present invention relates to a white light emitting device, and more specifically to a white light emitting device having uniform white chromaticity and enhanced luminance, by molding a light emitting diode chip with a cast resin mixed with at least two kinds of phosphors which have different excited luminescence characteristics from each other, and corpuscles for scattering light emitted from the light emitting diode chip.
  • a white light emitting device emits white light which is comprised of blue light emitted from a light emitting diode chip, which is a kind of a nitride compound semiconductor device, and yellow light emitted from a yttrium-aluminum- garnet fluorescent material (YAG fluorescent material) on the chip, which absorbs a part of the blue light.
  • a light emitting diode chip which is a kind of a nitride compound semiconductor device
  • yellow light emitted from a yttrium-aluminum- garnet fluorescent material (YAG fluorescent material) on the chip, which absorbs a part of the blue light.
  • YAG fluorescent material yttrium-aluminum- garnet fluorescent material
  • the light emitting diode chip is mounted on a printed circuit board (PCB) or on a lead terminal, and is electrically connected thereto. Furthermore, the light emitting diode chip is molded with a casting resin such as epoxy resin.
  • the YAG fluorescent material including Y and Al is activated with cerium (Ce).
  • Ce cerium
  • Y can be substituted with Gd for efficiently absorbing the blue light
  • the Al can be substituted with Ga for controlling chromaticity of the white light.
  • the emitted white light is comprised of the yellow light emitted from YAG fluorescent material such as Y 3 AI 5 O 12 : Ce and blue light, which is a complementary color to yellow light, it lacks red light when using only the YAG fluorescent material. Accordingly, perfect white light can not be produced.
  • Gd substituted with Y converts blue light to red light of a longer wavelength, but the luminance of the device becomes deteriorated according to the addition of Gd.
  • the fluorescent material is dispersed in the fluid epoxy resin for molding the light emitting diode chip and its specific gravity is higher than that of the epoxy resin, the fluorescent material settles down and concentrates around the light emitting diode chip.
  • the most of the fluorescent material concentrates at the inside of a reflector cup of the lead terminal, especially around the light emitting diode chip, so that the blue light is hardly transmitted. Accordingly, the preferable white light can not be produced and the luminance of the light emitting device deteriorates.
  • the light emitted from the light emitting diode chip is absorbed by the fluorescent material.
  • the power of the chip is raised in order to overcome the absorption, the chip is overheated which causes the fluorescent materials to be easily deteriorated, and the luminance and reliability of the light emitting device is decreased.
  • the present invention is to solve the problems described above, and it is an objective of the present invention to provide a white light emitting device which emits white light having enhanced chromaticity by mixing a primary light and converted lights emitted from at least two kinds of phosphors.
  • a white light emitting device comprising a light emitting diode chip generating blue light having a wavelength range of 430-480 nm; and a cured compound member which seals the light emitting diode chip, and is formed by heating and curing a liquid or solid epoxy resin.
  • the liquid or solid epoxy resin is mixed with at least two kinds of phosphors and corpuscles having high reflectance of light.
  • the at least two kinds of phosphors are capable of absorbing a part of light generated by the light emitting diode chip, and emitting light of different wavelength ranges from each other.
  • the phosphors and corpuscles are mixed at 0-45 wt% with respect to the weight of epoxy resin.
  • the phosphors are a sulfide fluorescent material emitting red light when excited and a garnet fluorescent material emitting both red light and yellow light when excited.
  • the corpuscles are at least one element selected from the group consisting of MgO, AI 2 O 3 , Fe 2 O 3 , PtO, AgO, Au, Cr, and Cu with high reflectance of light.
  • the corpuscles are mixed at 0-40 wt% with respect to an entire weight of phosphors, and more preferably at 1-10 wt% with respect to the entire weight of phosphors.
  • a white light emitting device in accordance with the invention comprises a light emitting diode chip generating ultraviolet light having a wavelength range of 360-410 nm; and a cured compound member which seals the light emitting diode chip, and is formed by heating and curing of a liquid or solid epoxy resin.
  • the liquid or solid epoxy resin is mixed with at least three kinds of phosphors and corpuscles having high reflectance of light.
  • the at least three kinds of phosphors are capable of absorbing a part of light generated by the light emitting diode chip, and emitting light of different wavelength ranges from each other.
  • the phosphors and corpuscles are mixed at 0-45 wt% with respect to the weight of epoxy resin, and the phosphors are a mixture of Y 2 O 2 S:Eu, ZnS:Cu, Au, Al, and (Sr, Ca, Ba, Mg) 10 (PO 4 ) 6 C 12 :Eu in a predetermined mixing ratio.
  • Fig. 1 is a longitudinal sectional view showing an example of a surface- mounted white light emitting device according to the present invention.
  • Fig. 2 is a longitudinal sectional view showing an example of a lamp-type white light emitting device according to the present invention.
  • Fig. 3 is a graph showing the emission spectrum of the garnet fluorescent material excited by absorbed light having a wavelength of 470 nm.
  • Fig. 4 is a graph showing the emission spectrum of a sulfide fluorescent material excited by absorbed light having a wavelength of 470 nm.
  • Fig. 5 is a graph showing the emission spectrum of another sulfide fluorescent material excited by absorbed light having a wavelength of 470 nm.
  • Fig. 6 is a schematic sectional view showing the path of the light generated from the light emitting device according to an embodiment of the present invention.
  • Fig. 1 shows a surface- mounted white light emitting device
  • Fig. 2 shows a lamp-type white light emitting device.
  • the surface mounted light emitting device has a lead frame 1 having a reflector 12, which is disposed near a terminal pattern, and a light emitting diode chip 2 which is mounted inward of the reflector 12 and has an emission wavelength within the range of 360-410 nm or 430-480 nm.
  • the reflector 12 is formed with a plastic resin or ceramic materials.
  • the reflector 12 is composed of a polyhedron of which each facet has a constant thickness and encloses both an anode and a cathode of the lead frame 1 formed by depositing and patterning of a thin film.
  • the light emitting diode chip 2 is fixed to an electrode 11 with a conductive or non-conductive adhesive.
  • a fluid or solid epoxy resin is filled within the reflector 12 such that a cured compound member 3 is formed by heating and curing the epoxy resin over a predetermined time period.
  • the lamp-type white light emitting device has a first lead terminal 10a having a reflecting cup 110 on its upper end for reflecting light, and a second lead terminal 10b apart from the first lead terminal 10b by a predetermined distance.
  • the light emitting diode chip 20 is mounted within the reflecting cup 110 of the first lead terminal 10a.
  • a fluid or solid epoxy resin seals on the light emitting diode chip 20 such that an inner cured compound member 30 is formed by heating and curing the epoxy resin.
  • an outer cured compound member 40 is formed around the first lead terminal 10a and the second lead terminal 10b, utilizing a mold for casting (not shown).
  • the cured member 3 or 30 contains at least two kinds of phosphors as well as corpuscles having high light reflectance. Each kind of the phosphors absorbs light emitted from the light emitting diode chip 2 or 20 and emits light of a wavelength different from that of the absorbed light as well as different from each other.
  • phosphors 50 which are excited by the absorbed light from the light emitting diode chip 20, and the corpuscles 60 are only dispersed within the reflecting cup 110 in the inner cured compound member 30.
  • the outer cured compound member 40 is formed of a transparent epoxy resin in order to enhance transmittance of the light emitted from the emitting diode chip 20.
  • the phosphors 50 and corpuscles 60 are mixed at 0-45 wt% with respect to a solid or fluid epoxy resin.
  • the phosphors 50 are a garnet fluorescent material and a sulfide fluorescent material.
  • the garnet fluorescent material is activated with Cr and Ce, and emits yellow light when excited.
  • the sulfide fluorescent material emits red light when excited.
  • the sulfide fluorescent material is mixed at 0.2-40 wt% with respect to the garnet fluorescent material.
  • a fluorescent material is comprised of a host lattice and activated ions (activators) mixed with impurities at a suitable location in the lattice.
  • the activated ions function as a determinant of the energy levels related to the fluorescence process, which fix the color of emitted light.
  • the color of the emitted light is determined based on an energy gap between a ground state and an excited state of the activated ions in the host lattice.
  • the primary color of light emitted from the fluorescent material with activated ions is substantially determined based on the state of the activated ions, namely the energy level.
  • the garnet fluorescent material used in the embodiment of the present invention is, because of its garnet structure, resistant to heat, light, and moisture, and is activated with Cr or Ce which have good fluorescence characteristics.
  • the structure of the garnet fluorescent material is represented by the general formula A 3 B 2 C 3 ⁇ 12 , where the A is selected from a group consisting of Sr, Sc, and Zr; the B is selected from a group consisting of Al, Ga, In, and Ti; and the C is selected from a group consisting of Al, Ga, In, Ti, and Si.
  • the garnet fluorescent material activated with Cr and Ce has a red and yellow emission spectrum when it is excited by blue light at a wavelength of 470 nm.
  • Fig. 3 is a graph showing the emission spectrum of a fluorescent material of (Sr, Sc) 3 AI 5 O 12 : Ce, Cr when exited by a blue light at a wavelength of 470 nm. It has a yellow emission peak wavelength at 580 nm by Ce ions, and a red emission peak wavelength of 700 nm by Cr ions.
  • Fig. 3 shows the emission under the condition that Cr is mixed at 20 wt% with respect to Ce. The intensity ratio of the yellow light and the red light can be adjusted by controlling the mixing ratio of Cr and Ce.
  • the sulfide fluorescent material absorbs light of a wavelength range from
  • sulfide fluorescent material of (Zn, Cd)S:Ag, CI is capable of emitting light of a high luminance with stable fluorescence characteristics. When it absorbs light of a wavelength of 470 nm, it emits red light of a wavelength within the range of 670 nm to 680 nm, as shown in Fig. 4.
  • the sulfide fluorescent material of (Zn, Cd)S:Ag, CI absorbs the light emitted from the light emitting diode 2 or 20, and emits red light such that the absorbed light is converted into light having a relatively long wavelength.
  • a sulfide fluorescent material 50 such as Y 2 O 2 S:Eu. It has emission characteristics of red light without cadmium. When it absorbs light having a wavelength of 470 nm, it emits red light having wavelength at the range of 630-650 nm.
  • the corpuscles 60 according to the present invention can promote light emission so as to increase the available amount of photons by scattering to diversify the path of the blue light without any energy loss.
  • the corpuscles 60 are selected from a group consisting of MgO, AI 2 O 3 , Fe 2 O 3 , PtO, AgO, Au, Cu, and Cr, which have a high reflectance, low oxidization, and good ionic bond characteristics with small ionization tendency.
  • the corpuscles according to the present invention are mixed at 0-40 wt%, preferably 0-10 wt% with respect to the entire weight of phosphors which are at least two kind of fluorescent materials.
  • the diameter of the corpuscles is within the range of 0.2 ⁇ m-70 .
  • the diameter of the corpuscles is related to the transmittance and scattering rate of the light emitted from the light emitting diode chip. Accordingly, when the diameter of the corpuscles is within the preferred range, luminance of the light emitted from the light emitting diode as well as the productivity can be enhanced.
  • the white light emitting device has a light emitting chip 2 or 20 which emits ultraviolet light having a wavelength within the range of 360-410 nm
  • the phosphors are at least three kinds of phosphors such as Y 2 O 2 S:Eu,
  • Each kind of the phosphors absorbs light emitted from the light emitting diode chip 2 or 20 and emits light of a wavelength different from that of the absorbed light as well as different from each other.
  • the phosphors and the corpuscles 60 are mixed at 0-45wt% with respect to the fluid or solid epoxy resin.
  • the corpuscles 60 are at least one element selected from the group consisting of MgO, AI 2 O 3 , Fe 2 O 3 , PtO, AgO, Au, and Cr, and are preferably mixed at 0-40 wt%, and more preferably at 0-10 wt% with respect to the entire weight of the phosphors.
  • the above-described white light emitting device can be operated as follows.
  • the light emitting diode chip 2 or 20 When current is applied to the white light emitting device according to the first embodiment of the present invention, the light emitting diode chip 2 or 20 emits blue light having a wavelength of near 470 nm. A part of the blue light is transmitted into the cured compound member, while some part of the blue light is absorbed to the phosphors 50a, 50b and excites them.
  • the kinetic energy of the blue light can make the photons move along a relatively long mean free path of about 1-2mm under a pressure of 1atm before stopping.
  • the activated ions in the sulfide fluorescent material 50a are excited by the photons and emit red light and yellow light during the transition from the excited state to a ground state.
  • the activated ions in the garnet fluorescent material 50b are excited by the photons and red light during the transition from the excited state to a ground state.
  • a part of converted light emitted from the phosphors or a part of primary light emitted from the light emitting diode chip may be absorbed by another phosphor or the epoxy resin, or they may interfere destructively with each other to vanish during the travel in the cured compound member.
  • the corpuscles are dispersed in the cured compound member 3 or 30 between the ' phosphors so that they may reflect and scatter light in various optical paths in the cured compound, resulting in light loss by absorption or destructive interference being highly reduced.
  • white light emission is accomplished by color mixing light, which is comprised of blue light that is not absorbed to the phosphors 50a and 50b and the converted light from the phosphors 50a and 50b.
  • the intensity of radiation is increased owing to the photons colliding with the corpuscles 60 so that both emission efficiency and the luminance of the white light emitting device are enhanced. Furthermore, white light emitted from the device according to the present invention has no lack of red light since it has the red and yellow light converted by the garnet fluorescent material activated by Cr and Ce ions and the red light converted by the sulfide fluorescent material 50b activated by CI ions.
  • the emission spectrum of the light emitting device according to the present invention has a relatively wide wavelength range so that a light emitting device of a desired color can be easily produced and controlled by adjusting the emission spectrum.
  • the white light emitting device is operated as follows.
  • the light emitting diode chip 2 or 20 emits ultraviolet light having a wavelength range of 390-410 nm. A part of the ultraviolet light is transmitted into the cured compound member, while some part of the ultraviolet light is absorbed to the phosphors and excites them.
  • the photons of ultraviolet light are absorbed by the Y 2 O 2 S fluorescent material activated with Eu ions, and then the excited Eu ions emit red light.
  • the photons of ultraviolet light are absorbed by the ZnS fluorescent material activated with Cu, Au, and Al ions, and then the excited ions emit green light.
  • the photons of ultraviolet light are absorbed by (Sr, Ca, Ba, Mg) 10 (PO 4 ) 6 C 12 activated with Eu ions, and emit blue light.
  • the light emitting device emits white light by mixing red, green, and blue light respectively emitted from the three phosphors.
  • sulfide fluorescent material with high stability is adapted for wavelength conversion so that white light with high luminance can be emitted.
  • At least two kinds of phosphors which have different fluorescence characteristics from each other, are adapted for forming the white light emitting device such that uniform white chromaticity, enhanced luminance, and good productivity can be achieved.
  • the intensity of radiation is increased by corpuscles mixed with the phosphors so that luminance of the white light emitting device is enhanced without any increase of the power of the light emitting diode chip.

Landscapes

  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Power Engineering (AREA)
  • Led Device Packages (AREA)

Abstract

A white light emitting device is enhanced in luminance by sealing a light emitting diode chip with a cast resin mixed with at least two kinds of phosphors and corpuscles of high reflectance. The white light emitting device includes a light emitting diode chip generating ultraviolet light having a wavelength range of 360-410 nm or a blue or violet light having a wavelength range of 430-480 nm and a cured compound member. The cure compound member is a liquid or solid epoxy resin mixed with at least two kinds of phosphors capable of absorbing a part of light generated by the light emitting diode chip and emitting lights of different wavelength ranges from each other, and corpuscles having high reflectance of light.

Description

TITLE OF THE INVENTION WHITE LIGHT EMITTING DEVICE
BACKGROUND OF THE INVENTION (a) Field of the invention
The present invention relates to a white light emitting device, and more specifically to a white light emitting device having uniform white chromaticity and enhanced luminance, by molding a light emitting diode chip with a cast resin mixed with at least two kinds of phosphors which have different excited luminescence characteristics from each other, and corpuscles for scattering light emitted from the light emitting diode chip. (b) Description of the Related Art
Generally, a white light emitting device emits white light which is comprised of blue light emitted from a light emitting diode chip, which is a kind of a nitride compound semiconductor device, and yellow light emitted from a yttrium-aluminum- garnet fluorescent material (YAG fluorescent material) on the chip, which absorbs a part of the blue light.
In the conventional white light emitting device, the light emitting diode chip is mounted on a printed circuit board (PCB) or on a lead terminal, and is electrically connected thereto. Furthermore, the light emitting diode chip is molded with a casting resin such as epoxy resin.
Then, the YAG fluorescent material including Y and Al is activated with cerium (Ce). Y can be substituted with Gd for efficiently absorbing the blue light, and the Al can be substituted with Ga for controlling chromaticity of the white light. However, since the emitted white light is comprised of the yellow light emitted from YAG fluorescent material such as Y3AI5O12: Ce and blue light, which is a complementary color to yellow light, it lacks red light when using only the YAG fluorescent material. Accordingly, perfect white light can not be produced.
Furthermore, Gd substituted with Y converts blue light to red light of a longer wavelength, but the luminance of the device becomes deteriorated according to the addition of Gd.
In the conventional fabrication process of the white light emitting device, since the fluorescent material is dispersed in the fluid epoxy resin for molding the light emitting diode chip and its specific gravity is higher than that of the epoxy resin, the fluorescent material settles down and concentrates around the light emitting diode chip.
Specifically, in the case of a lamp-type light emitting device, the most of the fluorescent material concentrates at the inside of a reflector cup of the lead terminal, especially around the light emitting diode chip, so that the blue light is hardly transmitted. Accordingly, the preferable white light can not be produced and the luminance of the light emitting device deteriorates.
There have been some problems in that the color of the light may be changed according to the viewing angle, and the white light emitting devices produced by the same fabrication process may emit different colors of light, because the fluorescent material is not uniformly dispersed in the casting resin.
Furthermore, some amount of the light emitted from the light emitting diode chip is absorbed by the fluorescent material. When the power of the chip is raised in order to overcome the absorption, the chip is overheated which causes the fluorescent materials to be easily deteriorated, and the luminance and reliability of the light emitting device is decreased.
SUMMARY OF THE INVENTION Thus, the present invention is to solve the problems described above, and it is an objective of the present invention to provide a white light emitting device which emits white light having enhanced chromaticity by mixing a primary light and converted lights emitted from at least two kinds of phosphors.
Furthermore, it is another objective of the invention to provide a white light emitting device having enhanced reliability and natural color characteristics by controlling the chromaticity of white light based on the amount of the phosphors. It is still another objective of the invention to provide a white light emitting device which has two kinds of phosphors and metal corpuscles, in order to minimize light loss due to excitation and to increase output luminance.
With the foregoing and other objects in view, there is provided, in accordance with the invention, a white light emitting device comprising a light emitting diode chip generating blue light having a wavelength range of 430-480 nm; and a cured compound member which seals the light emitting diode chip, and is formed by heating and curing a liquid or solid epoxy resin. The liquid or solid epoxy resin is mixed with at least two kinds of phosphors and corpuscles having high reflectance of light. The at least two kinds of phosphors are capable of absorbing a part of light generated by the light emitting diode chip, and emitting light of different wavelength ranges from each other.
Preferably, the phosphors and corpuscles are mixed at 0-45 wt% with respect to the weight of epoxy resin. Preferably, the phosphors are a sulfide fluorescent material emitting red light when excited and a garnet fluorescent material emitting both red light and yellow light when excited.
Preferably, the corpuscles are at least one element selected from the group consisting of MgO, AI2O3, Fe2O3, PtO, AgO, Au, Cr, and Cu with high reflectance of light.
Preferably, the corpuscles are mixed at 0-40 wt% with respect to an entire weight of phosphors, and more preferably at 1-10 wt% with respect to the entire weight of phosphors.
Furthermore, a white light emitting device in accordance with the invention comprises a light emitting diode chip generating ultraviolet light having a wavelength range of 360-410 nm; and a cured compound member which seals the light emitting diode chip, and is formed by heating and curing of a liquid or solid epoxy resin. The liquid or solid epoxy resin is mixed with at least three kinds of phosphors and corpuscles having high reflectance of light. The at least three kinds of phosphors are capable of absorbing a part of light generated by the light emitting diode chip, and emitting light of different wavelength ranges from each other.
Preferably, the phosphors and corpuscles are mixed at 0-45 wt% with respect to the weight of epoxy resin, and the phosphors are a mixture of Y2O2S:Eu, ZnS:Cu, Au, Al, and (Sr, Ca, Ba, Mg)10(PO4)6C12:Eu in a predetermined mixing ratio. BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a longitudinal sectional view showing an example of a surface- mounted white light emitting device according to the present invention.
Fig. 2 is a longitudinal sectional view showing an example of a lamp-type white light emitting device according to the present invention. Fig. 3 is a graph showing the emission spectrum of the garnet fluorescent material excited by absorbed light having a wavelength of 470 nm.
Fig. 4 is a graph showing the emission spectrum of a sulfide fluorescent material excited by absorbed light having a wavelength of 470 nm.
Fig. 5 is a graph showing the emission spectrum of another sulfide fluorescent material excited by absorbed light having a wavelength of 470 nm.
Fig. 6 is a schematic sectional view showing the path of the light generated from the light emitting device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, referring to the attached drawings, preferred embodiments of the present invention will be described.
Referring to Figs. 1 and 2, examples of white light emitting devices according to the present invention will be described. Fig. 1 shows a surface- mounted white light emitting device, while Fig. 2 shows a lamp-type white light emitting device.
Referring first to Fig. 1 , the surface mounted light emitting device has a lead frame 1 having a reflector 12, which is disposed near a terminal pattern, and a light emitting diode chip 2 which is mounted inward of the reflector 12 and has an emission wavelength within the range of 360-410 nm or 430-480 nm. The reflector 12 is formed with a plastic resin or ceramic materials. The reflector 12 is composed of a polyhedron of which each facet has a constant thickness and encloses both an anode and a cathode of the lead frame 1 formed by depositing and patterning of a thin film.
The light emitting diode chip 2 is fixed to an electrode 11 with a conductive or non-conductive adhesive. In order to protect the light emitting diode chip 2 from moisture or dust, a fluid or solid epoxy resin is filled within the reflector 12 such that a cured compound member 3 is formed by heating and curing the epoxy resin over a predetermined time period.
Referring now to Fig. 2, the lamp-type white light emitting device has a first lead terminal 10a having a reflecting cup 110 on its upper end for reflecting light, and a second lead terminal 10b apart from the first lead terminal 10b by a predetermined distance.
Similarly to the description above, the light emitting diode chip 20 is mounted within the reflecting cup 110 of the first lead terminal 10a. A fluid or solid epoxy resin seals on the light emitting diode chip 20 such that an inner cured compound member 30 is formed by heating and curing the epoxy resin. Subsequently, an outer cured compound member 40 is formed around the first lead terminal 10a and the second lead terminal 10b, utilizing a mold for casting (not shown).
In accordance with a light emitting device as shown in Fig. 1 or Fig. 2, the cured member 3 or 30 contains at least two kinds of phosphors as well as corpuscles having high light reflectance. Each kind of the phosphors absorbs light emitted from the light emitting diode chip 2 or 20 and emits light of a wavelength different from that of the absorbed light as well as different from each other. In the case of a lamp-type light emitting device, phosphors 50, which are excited by the absorbed light from the light emitting diode chip 20, and the corpuscles 60 are only dispersed within the reflecting cup 110 in the inner cured compound member 30. The outer cured compound member 40 is formed of a transparent epoxy resin in order to enhance transmittance of the light emitted from the emitting diode chip 20.
The phosphors 50 and corpuscles 60 are mixed at 0-45 wt% with respect to a solid or fluid epoxy resin.
In accordance with a first embodiment of the present invention, when the light emitting diode chip 2 or 20 emits blue or violet light within the wavelength range of 430-480 nm, the phosphors 50 are a garnet fluorescent material and a sulfide fluorescent material. The garnet fluorescent material is activated with Cr and Ce, and emits yellow light when excited. The sulfide fluorescent material emits red light when excited. The sulfide fluorescent material is mixed at 0.2-40 wt% with respect to the garnet fluorescent material. Typically, a fluorescent material is comprised of a host lattice and activated ions (activators) mixed with impurities at a suitable location in the lattice. The activated ions function as a determinant of the energy levels related to the fluorescence process, which fix the color of emitted light. The color of the emitted light is determined based on an energy gap between a ground state and an excited state of the activated ions in the host lattice.
The primary color of light emitted from the fluorescent material with activated ions is substantially determined based on the state of the activated ions, namely the energy level.
The garnet fluorescent material used in the embodiment of the present invention is, because of its garnet structure, resistant to heat, light, and moisture, and is activated with Cr or Ce which have good fluorescence characteristics. The structure of the garnet fluorescent material is represented by the general formula A3B2C3θ12, where the A is selected from a group consisting of Sr, Sc, and Zr; the B is selected from a group consisting of Al, Ga, In, and Ti; and the C is selected from a group consisting of Al, Ga, In, Ti, and Si.
The garnet fluorescent material activated with Cr and Ce has a red and yellow emission spectrum when it is excited by blue light at a wavelength of 470 nm. Fig. 3 is a graph showing the emission spectrum of a fluorescent material of (Sr, Sc)3AI5O12: Ce, Cr when exited by a blue light at a wavelength of 470 nm. It has a yellow emission peak wavelength at 580 nm by Ce ions, and a red emission peak wavelength of 700 nm by Cr ions. Fig. 3 shows the emission under the condition that Cr is mixed at 20 wt% with respect to Ce. The intensity ratio of the yellow light and the red light can be adjusted by controlling the mixing ratio of Cr and Ce. The sulfide fluorescent material absorbs light of a wavelength range from
430 nm to 530 nm which is emitted from the light emitting diode chip, and then emits red light. It is represented by the general formula (Zn-ι-xCdx)S : Ag, CI, where O≤x≤I .O, or the formula Y2O2S : Eu, and is activated with at least one element selected from Al, CI, and Eu. In particular, the sulfide fluorescent material of (Zn, Cd)S:Ag, CI is capable of emitting light of a high luminance with stable fluorescence characteristics. When it absorbs light of a wavelength of 470 nm, it emits red light of a wavelength within the range of 670 nm to 680 nm, as shown in Fig. 4.
The sulfide fluorescent material of (Zn, Cd)S:Ag, CI absorbs the light emitted from the light emitting diode 2 or 20, and emits red light such that the absorbed light is converted into light having a relatively long wavelength.
It is possible to employ another kind of a sulfide fluorescent material 50, such as Y2O2S:Eu. It has emission characteristics of red light without cadmium. When it absorbs light having a wavelength of 470 nm, it emits red light having wavelength at the range of 630-650 nm.
The corpuscles 60 according to the present invention can promote light emission so as to increase the available amount of photons by scattering to diversify the path of the blue light without any energy loss.
The corpuscles 60 are selected from a group consisting of MgO, AI2O3, Fe2O3, PtO, AgO, Au, Cu, and Cr, which have a high reflectance, low oxidization, and good ionic bond characteristics with small ionization tendency.
The corpuscles according to the present invention are mixed at 0-40 wt%, preferably 0-10 wt% with respect to the entire weight of phosphors which are at least two kind of fluorescent materials. The diameter of the corpuscles is within the range of 0.2 μm-70 .
The diameter of the corpuscles is related to the transmittance and scattering rate of the light emitted from the light emitting diode chip. Accordingly, when the diameter of the corpuscles is within the preferred range, luminance of the light emitted from the light emitting diode as well as the productivity can be enhanced.
Hereinafter, a second embodiment of the white light emitting device in accordance with the present invention will be described.
The white light emitting device has a light emitting chip 2 or 20 which emits ultraviolet light having a wavelength within the range of 360-410 nm The phosphors are at least three kinds of phosphors such as Y2O2S:Eu,
(ZnS:Cu, Au, Al),. and (Sr, Ca, Ba, Mg)10(PO4)6C12:Eu in a predetermined ratio. For example, phosphors are preferably set to be Y2O2S:Eu: (ZnS:Cu, Au, AI):(Sr, Ca, Ba, Mg)ιo(PO4)6C12:Eu = 13:1 :3. Each kind of the phosphors absorbs light emitted from the light emitting diode chip 2 or 20 and emits light of a wavelength different from that of the absorbed light as well as different from each other.
The phosphors and the corpuscles 60 are mixed at 0-45wt% with respect to the fluid or solid epoxy resin.
The corpuscles 60 are at least one element selected from the group consisting of MgO, AI2O3, Fe2O3, PtO, AgO, Au, and Cr, and are preferably mixed at 0-40 wt%, and more preferably at 0-10 wt% with respect to the entire weight of the phosphors.
The above-described white light emitting device can be operated as follows.
When current is applied to the white light emitting device according to the first embodiment of the present invention, the light emitting diode chip 2 or 20 emits blue light having a wavelength of near 470 nm. A part of the blue light is transmitted into the cured compound member, while some part of the blue light is absorbed to the phosphors 50a, 50b and excites them.
Then, the kinetic energy of the blue light can make the photons move along a relatively long mean free path of about 1-2mm under a pressure of 1atm before stopping.
As shown in Fig. 6, when the reference numeral 50a designates the garnet fluorescent material and the reference numeral 50b designates the sulfide fluorescent material, the activated ions in the sulfide fluorescent material 50a are excited by the photons and emit red light and yellow light during the transition from the excited state to a ground state. Similarly, the activated ions in the garnet fluorescent material 50b are excited by the photons and red light during the transition from the excited state to a ground state. It is possible that a part of converted light emitted from the phosphors or a part of primary light emitted from the light emitting diode chip may be absorbed by another phosphor or the epoxy resin, or they may interfere destructively with each other to vanish during the travel in the cured compound member.
However, in the above embodiments according to the present invention, the corpuscles are dispersed in the cured compound member 3 or 30 between the' phosphors so that they may reflect and scatter light in various optical paths in the cured compound, resulting in light loss by absorption or destructive interference being highly reduced.
Accordingly, white light emission is accomplished by color mixing light, which is comprised of blue light that is not absorbed to the phosphors 50a and 50b and the converted light from the phosphors 50a and 50b.
The intensity of radiation is increased owing to the photons colliding with the corpuscles 60 so that both emission efficiency and the luminance of the white light emitting device are enhanced. Furthermore, white light emitted from the device according to the present invention has no lack of red light since it has the red and yellow light converted by the garnet fluorescent material activated by Cr and Ce ions and the red light converted by the sulfide fluorescent material 50b activated by CI ions.
The emission spectrum of the light emitting device according to the present invention has a relatively wide wavelength range so that a light emitting device of a desired color can be easily produced and controlled by adjusting the emission spectrum.
The white light emitting device according to the second embodiment of the present invention is operated as follows. When current is applied to the white light emitting device according to the second embodiment of the present invention, the light emitting diode chip 2 or 20 emits ultraviolet light having a wavelength range of 390-410 nm. A part of the ultraviolet light is transmitted into the cured compound member, while some part of the ultraviolet light is absorbed to the phosphors and excites them. The photons of ultraviolet light are absorbed by the Y2O2S fluorescent material activated with Eu ions, and then the excited Eu ions emit red light. On the other hand, the photons of ultraviolet light are absorbed by the ZnS fluorescent material activated with Cu, Au, and Al ions, and then the excited ions emit green light. The photons of ultraviolet light are absorbed by (Sr, Ca, Ba, Mg)10(PO4)6C12 activated with Eu ions, and emit blue light.
Accordingly, the light emitting device emits white light by mixing red, green, and blue light respectively emitted from the three phosphors.
As described above, according to the white light emitting device of the present invention, sulfide fluorescent material with high stability is adapted for wavelength conversion so that white light with high luminance can be emitted.
Furthermore, at least two kinds of phosphors, which have different fluorescence characteristics from each other, are adapted for forming the white light emitting device such that uniform white chromaticity, enhanced luminance, and good productivity can be achieved.
The intensity of radiation is increased by corpuscles mixed with the phosphors so that luminance of the white light emitting device is enhanced without any increase of the power of the light emitting diode chip.

Claims

WHAT IS CLAIMED IS:
1. A white light emitting device comprising: a light emitting diode chip generating blue light having a wavelength range of 430-480 nm; and a cured compound member which seals the light emitting diode chip, and is formed by heating and curing of a liquid or solid epoxy resin, the liquid or solid epoxy resin being mixed with: at least two kinds of phosphors capable of absorbing a part of light generated by the light emitting diode chip and emitting lights of different wavelength ranges from each other, and corpuscles having high reflectance of light.
2. A white light emitting device of claim 1 , wherein the phosphors and corpuscles are mixed at 0-45 wt% with respect to the weight of epoxy resin.
3. A white light emitting device of claim 1 , wherein the phosphors are a sulfide fluorescent material emitting red light when excited and a garnet fluorescent material emitting both red light and yellow light when excited.
4. A white light emitting device of claim 3, wherein the sulfide fluorescent material is mixed at a ratio of 0.2wt%-40 wt% with respect to the garnet fluorescent material.
5. A white light emitting device of claim 3, wherein the garnet fluorescent material is represented by a structural formula A3B2C3O12, where the A is at least one element selected from the group consisting of Sr, Sc, and Zr; the B is at least one element selected from the group consisting of Al, Ga, In, and Ti; the C is at least one element selected from the group consisting of Al, Ga, In, Ti, and Si; and the material is activated with Cr and Ce ions.
6. A white light emitting device of claim 3 or claim 4, wherein the sulfide fluorescent material is represented by the general formula (Zn1-xCdx)S : Ag, CI, where 0≤x≤1.0.
7. A white light emitting device of claim 3 or claim 4, wherein the sulfide fluorescent material is Y2O2S : Eu.
8. A white light emitting device of claim 1 , wherein the corpuscles are at least one element selected from the group consisting of MgO, AI2O3, Fe2O3, PtO, AgO, Au, Cr, and Cu, with high reflectance.
9. A white light emitting device of claim 1 or claim 8, wherein the corpuscles are mixed at 0-40 wt% with respect to an entire weight of the phosphors.
10. A white light emitting device comprising: a light emitting diode chip generating ultraviolet light having a wavelength range of 360-410 nm; and a cured compound member which seals the light emitting diode chip, and is formed by heating and curing of a liquid or solid epoxy resin, the liquid or solid epoxy resin being mixed with: at least three kinds of phosphors capable of absorbing a part of light generated by the light emitting diode chip and emitting lights of different wavelength ranges from each other; and corpuscles having high reflectance of light.
1 1. A white light emitting device of claim 10, wherein the phosphors and corpuscles are mixed at 0-45 wt% with respect to the weight of epoxy resin.
12. A white light emitting device of claim 10, wherein the phosphors are a mixture of Y2O2S:Eu, ZnS:Cu, Au, A), and (Sr, Ca, Ba, Mg)10(PO4)6C12:Eu in a predetermined mixing ratio.
13. A white light emitting device of claim 10, wherein the corpuscles are at least one element selected from the group consisting of MgO, AI2O3, Fe2O3, PtO, AgO, Au, and Cr, with high reflectance,.
14. A white light emitting device of claim 10 or claim 13, wherein the corpuscles are mixed at 0-40 wt% with respect to an entire weight of phosphors.
15. A white light emitting device comprising: a lead frame having a reflector or a lead terminal having a reflecting cup; a light emitting diode chip fixed on the reflector or the reflecting cup with a conductive or non-conductive adhesive; and a cured compound member, which seals the light emitting diode chip and is formed by heating and curing of a liquid or solid epoxy resin, wherein the light emitting diode chip generates ultraviolet light having a wavelength range of 360-410 nm or violet or blue light having a wavelength range of 430-480 nm, wherein at least two kinds of phosphors and corpuscles are dispersed in the cured compound member, the at least two kinds of phosphors capable of absorbing a part of light generated by the light emitting diode chip and emitting lights of different wavelength ranges from each other; and corpuscles having high ll reflectance of light.
16. A white light emitting device of claim 15, wherein the corpuscles and the phosphors are mixed at 0-45wt% with respect to the epoxy resin.
17. A white light emitting device of claim 15, wherein the corpuscles are at least one element selected from the group consisting of MgO, AI2O3, Fe2O3, PtO, AgO, Au, and Cr, with high light reflectance.
18. A white light emitting device of claim 1 or claim 17, wherein the corpuscles are mixed at 0-40 wt% with respect to an entire weight of the phosphors.
19. A white light emitting device according to any one of claims 1, 10, and 15, wherein the particle size of the corpuscles is within the range of 0.2 m-70 μm.
PCT/KR2002/002240 2002-08-21 2002-11-29 White light emitting device WO2004019422A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2002368183A AU2002368183A1 (en) 2002-08-21 2002-11-29 White light emitting device

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
KR2002/24862U 2002-08-21
KR20020024862 2002-08-21
KR1020020066353A KR100554453B1 (en) 2002-08-21 2002-10-30 White light emitting device
KR2002/66353 2002-10-30

Publications (1)

Publication Number Publication Date
WO2004019422A1 true WO2004019422A1 (en) 2004-03-04

Family

ID=31949613

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/KR2002/002240 WO2004019422A1 (en) 2002-08-21 2002-11-29 White light emitting device

Country Status (2)

Country Link
AU (1) AU2002368183A1 (en)
WO (1) WO2004019422A1 (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100365837C (en) * 2005-06-13 2008-01-30 北京有色金属研究总院 Illuminating device and its mfg. method
CN100428512C (en) * 2005-01-31 2008-10-22 东芝照明技术株式会社 Light-emitting diode apparatus
WO2013039418A1 (en) * 2011-01-13 2013-03-21 Закрытое Акционерное Общество "Научно-Производственная Коммерческая Фирма "Элтан Лтд" White-light light-emitting diode lamp with a remote reflective photoluminescent converter
US20160056134A1 (en) * 2012-08-15 2016-02-25 Epistar Corporation Light-emitting device
US11791370B2 (en) 2012-08-15 2023-10-17 Epistar Corporation Light-emitting device

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05152609A (en) * 1991-11-25 1993-06-18 Nichia Chem Ind Ltd Light emitting diode
JPH06119914A (en) * 1992-10-02 1994-04-28 Ise Electronics Corp Light emitting element
JPH0799345A (en) * 1993-09-28 1995-04-11 Nichia Chem Ind Ltd Light emitting diode
JPH09153645A (en) * 1995-11-30 1997-06-10 Toyoda Gosei Co Ltd Group-iii nitride semiconductor light-emitting device
US6066681A (en) * 1996-05-24 2000-05-23 Stepan Company Open celled polyurethane foams and methods and compositions for preparing such foams
KR20000029696A (en) * 1996-07-29 2000-05-25 오가와 에지 Light emitting device and display device
KR20020014130A (en) * 2000-08-16 2002-02-25 박득일 Backlight Unit with Blue LED and Green and Red Emitting Fluorescent Sheet and Producing White Light by Using the Same

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05152609A (en) * 1991-11-25 1993-06-18 Nichia Chem Ind Ltd Light emitting diode
JPH06119914A (en) * 1992-10-02 1994-04-28 Ise Electronics Corp Light emitting element
JPH0799345A (en) * 1993-09-28 1995-04-11 Nichia Chem Ind Ltd Light emitting diode
JPH09153645A (en) * 1995-11-30 1997-06-10 Toyoda Gosei Co Ltd Group-iii nitride semiconductor light-emitting device
US6066681A (en) * 1996-05-24 2000-05-23 Stepan Company Open celled polyurethane foams and methods and compositions for preparing such foams
KR20000029696A (en) * 1996-07-29 2000-05-25 오가와 에지 Light emitting device and display device
KR20020014130A (en) * 2000-08-16 2002-02-25 박득일 Backlight Unit with Blue LED and Green and Red Emitting Fluorescent Sheet and Producing White Light by Using the Same

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100428512C (en) * 2005-01-31 2008-10-22 东芝照明技术株式会社 Light-emitting diode apparatus
CN100365837C (en) * 2005-06-13 2008-01-30 北京有色金属研究总院 Illuminating device and its mfg. method
WO2013039418A1 (en) * 2011-01-13 2013-03-21 Закрытое Акционерное Общество "Научно-Производственная Коммерческая Фирма "Элтан Лтд" White-light light-emitting diode lamp with a remote reflective photoluminescent converter
US9136444B2 (en) 2011-01-13 2015-09-15 Vladimir Nikolaevich Ulasyuk LED white light source with remote photoluminescent reflecting converter
US20160056134A1 (en) * 2012-08-15 2016-02-25 Epistar Corporation Light-emitting device
US9825012B2 (en) * 2012-08-15 2017-11-21 Epistar Corporation Light-emitting device
US10083945B2 (en) 2012-08-15 2018-09-25 Epistar Corporation Light-emitting device
US10319703B2 (en) 2012-08-15 2019-06-11 Epistar Corporation Light bulb
US10593655B2 (en) 2012-08-15 2020-03-17 Epistar Corporation Light bulb
US10720414B2 (en) 2012-08-15 2020-07-21 Epistar Corporation Light bulb
US10886262B2 (en) 2012-08-15 2021-01-05 Epistar Corporation Light bulb
US11791370B2 (en) 2012-08-15 2023-10-17 Epistar Corporation Light-emitting device

Also Published As

Publication number Publication date
AU2002368183A1 (en) 2004-03-11

Similar Documents

Publication Publication Date Title
US6614170B2 (en) Light emitting diode with light conversion using scattering optical media
US7768189B2 (en) White LEDs with tunable CRI
US7138660B2 (en) Light emitting device
KR100816596B1 (en) Wavelength conversion pouring material, its use and manufacturing method
JP5422721B2 (en) White LED lamp, backlight and lighting device
US7229573B2 (en) Ce3+ and Eu2+ doped phosphors for light generation
JP4001893B2 (en) Semiconductor light emitting device
KR100609830B1 (en) White Semiconductor Light Emitted Device using Green-emitting and Red emitting Phosphor
US7859182B2 (en) Warm white LED-based lamp incoporating divalent EU-activated silicate yellow emitting phosphor
JP2012531043A (en) Phosphor conversion infrared LED related applications
EP1888711B1 (en) Light emitting device and phosphor of alkaline earth sulfide therefor
US20090114929A1 (en) White light emitting device
US7088038B2 (en) Green phosphor for general illumination applications
JP2008546877A (en) Conversion material for wavelength conversion, light emitting optical element and method for manufacturing the same
JP2002261328A (en) Light-emitting diode having optical conversion material using scattered optical medium
JP2003249689A (en) Light emitting device
US11450790B2 (en) Light emitting device
KR20080098330A (en) Light emitting device
KR100554453B1 (en) White light emitting device
WO2004019422A1 (en) White light emitting device
KR200309261Y1 (en) White light emitting device
JP2003197971A (en) Light emitting diode

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ OM PH PL PT RO RU SD SE SG SI SK SL TJ TM TN TR TT TZ UA UG US UZ VC VN YU ZA ZM ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR IE IT LU MC NL PT SE SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: JP

WWW Wipo information: withdrawn in national office

Country of ref document: JP