Source: http://www.google.com/patents/US20050001225?dq=7565338
Timestamp: 2017-10-20 07:58:28
Document Index: 173685215

Matched Legal Cases: ['art 2', 'art 8', 'arts 9', 'arts 3', 'art 1', 'art 2', 'art 3', 'art 4', 'art 5', 'art 6', 'art 7', 'art 8', 'art 9', 'art 10', 'art 3']

Patent US20050001225 - Light emitting apparatus and light emitting method - Google Patents
A light emitting apparatus has a light emitting element with an emission wavelength in the range of 360 to 550 nm and a rare-earth element doped oxide nitride phosphor or cerium ion doped lanthanum silicon nitride phosphor. Part of light radiated from the light emitting element is wavelength-converted...http://www.google.com/patents/US20050001225?utm_source=gb-gplus-sharePatent US20050001225 - Light emitting apparatus and light emitting method
Publication number US20050001225 A1
Application number US 10/722,563
Also published as US7858997, US20070164308
Publication number 10722563, 722563, US 2005/0001225 A1, US 2005/001225 A1, US 20050001225 A1, US 20050001225A1, US 2005001225 A1, US 2005001225A1, US-A1-20050001225, US-A1-2005001225, US2005/0001225A1, US2005/001225A1, US20050001225 A1, US20050001225A1, US2005001225 A1, US2005001225A1
Inventors Naoki Yoshimura, Yoshinobu Suehiro, Yuji Takahashi, Koichi Ota, Mamoru Mitomo, Tadashi Endo, Masakazu Komatsu
Original Assignee Toyoda Gosei Co., Ltd., Independent Administrative Institution, National Institute For Materials Science
Patent Citations (9), Referenced by (229), Classifications (45), Legal Events (1)
US 20050001225 A1
A light emitting apparatus has a light emitting element with an emission wavelength in the range of 360 to 550 nm and a rare-earth element doped oxide nitride phosphor or cerium ion doped lanthanum silicon nitride phosphor. Part of light radiated from the light emitting element is wavelength-converted by the phosphor. The light emitting apparatus radiates white light generated by a mixture of the wavelength-converted light and the other part of light radiated from the light emitting element.
2. The light emitting apparatus according to claim 1, wherein;
the emission wavelength is in the range of 450 to 550 nm, and the light emitting apparatus radiates white light generated by a mixture of the wavelength-converted light and the other part of light radiated from the light emitting element.
3. The light emitting apparatus according to claim 1, wherein;
the oxide nitride phosphor is of oxide nitride that contains α-sialon as matrix material.
4. The light emitting apparatus according to claim 1, wherein;
the phosphor is in the form of powder or particles and is contained in a light transmitting material.
5. The light emitting apparatus according to claim 1, wherein;
the light emitting element is III group nitride system compound semiconductor emitting element.
6. The light emitting apparatus according to claim 1, wherein;
the phosphor is represented by a general formula:
MexSi12−(m+n)Al(m+n)OnN16−n:Re1yRe2z, part or all of metal (Me), where Me is one or more of Li, Ca, mg, Y and lanthanide metals except for La and Ce, to be dissolved into α-sialon being replaced by lanthanide metal (Re1), where Re1 is one or more of Ce, Pr, Eu, Tb, Yb and Er, as luminescence center, or replaced by lanthanide metal (Re1) and lanthanide metal (Re2), where Re2 is Dy, co-activator.
7. The light emitting apparatus according to claim 6, wherein;
the phosphor satisfies, when the metal (Me) is bivalent, 0.6<m<3.0 and 0≦n<1.5 in the general formula.
8. The light emitting apparatus according to claim 6, wherein;
the phosphor satisfies, when the metal (Me) is trivalent, 0.9<m<4.5 and 0≦n<1.5 in the general formula.
9. The light emitting apparatus according to claim 6, wherein;
the phosphor is MexSi9.75Al2.25O0.75N15.25:Re1yRe2z to satisfy m=1.5 and n=0.75 in the general formula, where 0.3<x+y<0.75 and 0.01<y+z<0.7, where y>0.01, 0.0≦z<0.1, are satisfied.
10. The light emitting apparatus according to claim 6, wherein;
the phosphor is MexSi9.75Al2.25O0.75N15.25:Re1yRe2z to satisfy m=1.5 and n=0.75 in the general formula, where 0.3<x+z+y+z<1.5, 0.01<y<0.7 and 0.0≦z<0.1 are satisfied.
11. The light emitting apparatus according to claim 6, wherein;
the metal (Me) is calcium (Ca).
12. The light emitting apparatus according to claim 1, wherein;
the phosphor is sialon system phosphor powder that is composed of: α-sialon of 40 weight % or more and 90 weight % or less, the α-sialon being structured such that Ca site of Ca-α-sialon represented by: (Cax, My) (Si, Al)12(O, N)16 is partially replaced by metal (M): β-sialon of 5 weight % or more and 40 weight % or less; and unreacted silicon nitride of 5 weight % or more and 30 weight % or less, where M is metal that is one or more selected from Ce, Pr, Eu, Tb, Yb and Er and 0.05<(x+y)<0.3, 0.02<x<0.27 and 0.03<y<0.3.
13. The light emitting apparatus according to claim 12, wherein;
the entire phosphor powder has a chemical composition that is in the range of three composition lines of Si3N4-a (M2O3. 9AlN), Si3N4-b(CaO.3AlN) and Si3N4-c(AlN.Al2O3), where 4×10−3<a<4×10−2, 8×10−3<b<8×10−2 and 10−2<c<8×10−1 are satisfied.
14. A light emitting apparatus, comprising:
15. The light emitting apparatus according to claim 14, wherein:
the phosphor is represented by; La2-xSi3N5:xCe, where doping amount x is 0<x<1 and cerium ion is doped to lanthanum site in solid dissolution replacement.
16. The light emitting apparatus according to claim 14, wherein:
the doping amount x is 0.1<x<0.5 and the phosphor is ultraviolet ray excitation phosphor.
17. The light emitting apparatus according to claim 14, wherein:
the doping amount x is 0.0<x<0.2, and the phosphor is electron beam excitation phosphor.
18. The light emitting apparatus according to claim 14, wherein:
the phosphor radiates blue light.
19. A light emitting method for a light emitting apparatus that comprises a light emitting element with an emission wavelength in the range of 360 to 550 nm and a rare-earth element doped oxide nitride phosphor, wherein part of light radiated from the light emitting element is wavelength-converted by the phosphor, and the light emitting apparatus radiates light generated by a mixture of wavelength-converted light and the other part of light radiated from the light emitting element, comprising the step of:
20. A light emitting method for a light emitting apparatus that comprises a light emitting element with an emission wavelength in the range of 360 to 550 nm and a cerium ion doped lanthanum silicon nitride phosphor, wherein part of light radiated from the light emitting element is wavelength-converted by the phosphor, and the light emitting apparatus radiates light generated by a mixture of wavelength-converted light and the other part of light radiated from the light emitting element, comprising the step of:
21. The light emitting method according to claim 19, wherein:
the color of the light radiated from the light emitting apparatus is adjusted by controlling the turn-on time of the light emitting element.
22. The light emitting method according to claim 20, wherein:
23. The light emitting method according to claim 19, wherein:
24. The light emitting method according to claim 20, wherein:
25. The light emitting apparatus according to claim 19, wherein;
26. The light emitting apparatus according to claim 20, wherein;
Known oxide nitride phosphor are phosphor with β-sialon, matrix material (prior art 2, described later), Ce doped oxide nitride (Y—Al—O—N) with silicate mineral or apatite structure (prior art 8, described later). Ba1-xEuxAl11O16N with β-alumina structure (prior arts 9 and 10, described later). Also, recently reported is phosphor with oxynitride glass matrix material (prior arts 3 and 4, described later).
By the way white LED (light emitting diode) is used in a field requiring reliability such as disaster prevention light and traffic light, a field requiring light weight and small size such as in-vehicle light and LCD backlight and a field requiring visibility such as station guide plate. The emission color of white LED. i.e., white, is obtained by mixing lights with different emission colors. Namely, blue light generated from InGaN system blue LED with emission wavelength of 450 to 550 nm is mixed with yellow light generated from phosphor.
Prior art 1: German patent No. 789, 890
Prior art 2: Japanese patent application laid-open No. 60-206889
Prior art 3: Japanese patent application laid-open No. 2001-214162
Prior art 4: Japanese patent application laid-open No. 2002-76434
Prior art 5: “Izv. Akad. Nauk SSSR, Neorg. Master” 17(8), 1431-5
Prior art 6: T. Endo et al., “High pressure synthesis of periodic compound and its optical and electrical properties”, In T. T suruta, M. Doyama and Seno (Editors), New Functionality Materials, Volume C, Elsevier, Amsterdam, The Netherlands, pp. 107-112 (1993)
Prior art 7: S. S. Lee t al., “Photoluminescence and Electroluminescence characteristic of CaSiN2:Eu”, Proc. SPIE-Int, Soc. Opt. Eng., 3241, 75-83 (1997)
Prior art 8: J. W. H van Krevel at al., “Long wavelength Ce3+ emission in Y—Si—O—N materials”, J. Alloys and Compounds, 268, 272-277 (1998)
Prior art 9: H. Hintzen et al., “On the Exsitence of Europium Aluminum Oxynitrides with a Magnetopolumlite or β-Alumina-Type Structure”, J. Solid State Chem., 142, 48-50 (1999)
Prior art 10: S. R. Jansen et al., “Eu-Doped Barium Aluminum Oxynitride with β-Alumina-Type Structure as New Blue-Emitting Phosphor”, J. Electrocher. Soc., 146, 800-806 (1999)
However, in the conventional light emitting apparatus, which is composed of blue LED and YAG:Ce, its emission light have weak red component. Therefore, it lacks in color rendering property as to red color.
It is an object of the invention to provide light emitting apparatus and light emitting method that can improve the color rendering property as to red color.
FIG. 5 is a diagram showing the chemical composition range of mixture α-sialon phosphor (range sandwiched by two triangles indicated by oblique lines) and the chemical composition range of entire powder;
FIG. 15 is a top view (from phosphor layer side) showing the planar light source 7 in FIG. 15A;
FIG. 42 is a table showing atom % of Samples A to N, Ca-α-sialon:Eu2− phosphors;
FIG. 56 is a graph showing blue emission intensity, which belongs to transition of 2T2(5d1)→2F5/2(4f1) (at 440 nm) in Ce3+ ion, depending on the ratio of Ce3− ion doped in solid solution replacement to La3+ site of LaSi3N5; and
FIG. 57 is a spectrum diagram showing cathode luminescence spectra obtained by excitation with electron beam of 5 keV acceleration voltage in synthesized samples, La1-xSi3N5:xCe (x=0.6, 0.5, 0.4, 0.3, 0.2 and 0.1).
FIG. 1 is an illustration showing a lamp type (or shell type) LED as a light emitting apparatus in the first preferred embodiment according to the invention.
As shown in FIG. 1, the lamp type LED 1 is composed of: lead frames 30, 31; a light emitting element 10 that is mounted through adhesive 20 on a cup portion 33 of the lead frame 30; boding wires 40, 41 that connect between the lead frames 30, 31 and n-electrode, p-electrode of light emitting element 10; epoxy resin 35 (hereinafter referred to as phosphor resin), which contains phosphor 36 dispersed uniformly, filled in the cup portion 33, and sealing resin 50 of epoxy resin that seals the light emitting element 10, part of lead frames 30, 31 and bonding wires 40, 41. The LED 1 emits white series light and can be applied to, for example, a planar light source and a linear light source in combination with a light guiding member and further applied to various display devices.
The light emitting element 10 used has an emission wavelength of 360 nm to 550 nm. Such emission light can be obtained by exciting the phosphor 36 in high efficiency. In selecting emission wavelength of light emitting element 10, the excitation peak and emitted light color of phosphor 36 and the color of light emitted from the entire light emitting apparatus are considered, For example, in order to obtain white series emitted light, it is preferable that a light emitting element with an emission wavelength of 450 nm to 550 nm is used, and it is further preferable that a light emitting element with an emission wavelength of 450 nm to 550 nm is used. By using a light emitting element with different emission wavelength (emitted light color), the color of light radiated from the light emitting apparatus 1 can be varied.
The material of light emitting element 10 is not limited. It is preferable that the light emitting element is of III group nitride system compound semiconductor. The III group nitride system compound semiconductor is represented by a general formula: AlXGaYIn1-X-YN (0≦X≦1, 0≦Y≦1, 0≦X+Y≦1), and it includes a two-element system such as AIN. GaN and InN and a three-element system such as AlXGa1-XN, AlXIn1-XN and GaXIn1-XN (thus far, all 0<X<1). Part of III system element can be replaced by boron (B), tellurium (Te) and part of nitrogen (N) can be replaced by phosphorus (P), arsenic (As), antimony (Sb), bismuth (Bi) etc. It is preferable that the element function portion of light emitting element 10 is composed of two-element system or three-element system III group nitride system compound semiconductor.
Layers Composition Dopant
p-type layer 15 p-GaN(0.3 μm) Mg
light emitting layer 14 supper-lattice structure
repetition number of quantum 1 to 10
well and barrier layers
n-type layer 13 n-GaN (4 μm) Si
The buffer layer 12 is used to grow a high-quality semiconductor layer and is formed on the substrate 11 by MOCVD. In this embodiment AlN buffer layer is used, but not limited to that. Instead, GaN, InN (two-element system), III group nitride system compound semiconductor represented by: AlXGaYN (0<x<1, 0<y<1, x+y=1) (three-element system), and III group nitride system compound semiconductor represented by: AlaGabIn1-a-bN (0<a<1, 0≦b<1, a+b≦1) (four-element system) may be used.
The n-cladding layer 13 may be a two-layer structure of a lower electron density n− layer on the light emitting layer 14 side and a higher electron density n+ layer on the buffer layer 12 side. The latter is called n-type contact layer. The light emitting layer 14 is not limited to supper-lattice structure, and may be structured as single hetero type, double hetero type or homo junction type. Alternatively, it may be structured as MIS junction or PIN junction.
Between the light emitting layer 14 and the p-type layer 15, there may exit wide bandgap AlXGaYIn1-X-YN (0≦X≦1, 0≦Y≦1, X+Y≦1) with an acceptor such as Mg doped thereto. This is used for preventing electron injected in the light emitting layer 14 from diffusing into the p-type layer 15.
The p-type layer 15 maybe a two-layer structure of a lower hole density p− layer on the light emitting layer 14 side and a higher hole density p+ layer on p electrode 18 layer 12 side. The latter is called p-type contact layer.
As shown in FIG. 3, the light emitting element 100 is provided with the reflection layer 25 formed just under the light emitting layer 14. As shown in FIG. 6, the light emitting element 101 is provided with the reflection layer 26 formed on the surface of substrate with no semiconductor layer formed thereon. The reflection layer 25 is of metal nitride. It is preferably of one or more arbitrarily selected from titanium nitride, zirconium nitride and tantalum nitride. The reflection layer 26 is also of metal nitride. It may be of metal of Al, In, Cu, Ag, Pt, Ir, Pd, Rh, W, Mo, Ti, Ni etc. or an alloy of two or more arbitrarily selected from these metals.
The light emitting element 10 is mounted through the adhesive 20 on the cup portion 33 of lead frame 30. The adhesive 20 is Ag paste that Ag is mixed as filler into epoxy resin With this Ag paste, the radiation of heat generated from the light emitting element 10 can be enhanced. Instead of Ag paste, the other known adhesives may be used.
In this case, Me is preferably one or more of Ca. Y and lanthanide metals except for La and Ce, and it is further preferably Ca or Nd. The lanthanide metal (Re1) used for replacing is preferably Ce, Eu or Yb, and it is further preferably Ce or Eu.
Meanwhile, if part or all of metal (Me) replaced by one or more of Ce, Pr, Eu, Tb. Yb and Er (lanthanide metal (Re1)), or one or more of Ce, Pr, Eu, Tb, Yb and Er (lanthanide metal (Me) (Re1)) and Dy (lanthanide metal (Re2)), then the metal is not necessarily added and may be replaced by further preferable one.
A-sialon (α-sialon) has a higher nitrogen content than oxynitride glass and is represented by: NxSi12−(m−n)Al(m+n)OnN16−n where x is a value obtained dividing (m) by a valence of metal (M). Meanwhile, oxynitride glass is as described in prior art 3, such a phosphor that serves to shift the position of excitation/emission peak of conventional oxide system phosphors to the longer wavelength side by replacing oxygen atom surrounding the rare-metal element as luminescence center by nitrogen atom to relax the influence of surrounding atoms to electron of rare-metal element, and that has an excitation spectrum extending until visible region (≦500 μm).
Also, in the single-phase α-sialon phosphor, the metal (Me) is dissolved in the range of, at the minimum, one per three unit cells of α-sialon including four mass weights of (Si, Al)3(N,O)4 to, at the maximum, one per one unit cell thereof. The solid solubility limit is generally, in case of bivalent metal (Me), 0.6<m<3.0 and 0≦n<1.5 in the above formula and, in case of trivalent metal (Me), 0.9<m<4.5 and 0≦n<1.5. It is estimated that, in a region except for those regions, single-phase α-sialon phosphor is not obtained. Therefore, the regions defined above are preferable.
Namely, β-sialon is represented by: Si6−zAlzOzN8−z (0<z<0.2), and it is solid solution of β-type silicon nitride where part of Si sites is replaced by Al and part of N sites is replaced by O.
In contrast, α-sialon is represented by: MeXSi12−(m+n)Al(m+n)OnN16−n, and it is solid solution of α-type silicon nitride, where part of Si—N bonds is replaced by Al—N bond and a specific metal (Me) (Me is one or more of Li, Ca, Mg, Y and lanthanide metals except for La and Ce) invades between lattices and is dissolved therein.
In case of using β-sialon as matrix material, for example, a phosphor that is synthesized adding Er oxide to β-sialon as described in embodiments 33 to 35 of Japanese patent application laid-open No. 60-206889 radiates a blue luminescent light (410-440 nm). In α-sialon, as described later, rare-earth element doped oxide nitride phosphor radiates orange to red light (570-590 nm) due to the activation of Er. Viewing from this phenomenon it is assumed that Er is taken in the crystal structure of α-sialon and, thereby, Er is influenced by nitrogen atom composing the crystal and, therefore, the elongation of light source wavelength, which is very difficult to realize in phosphor with oxide as matrix material, can be easily generated.
Further, since the mixture α-sialon phosphor also has α-sialon as matrix material like the single-phase α-sialon phosphor, it can have the advantages of matrix material α-sialon, i.e. good chemical, mechanical and thermal properties. Thus, it offers a stable and long-lifetime phosphor material. Due to these properties, it can suppress thermal relaxation phenomenon causing a loss in excitation energy. Therefore, in α-sialon with dissolved rare-earth element as well as Ca in this embodiment, a ratio of reduction in emission intensity according to rise of temperature becomes small. Thus, the temperature range available can be broadened as compared to the conventional phosphor.
The mixture α-sialon phosphor is obtained by heating Si3N4—M2O3—CaO—AlN—Al2O3 system mixed powder at 1650 to 1900° C. in inert gas atmosphere to get a sintered body, then powdering it. Since CaO is so instable that it easily reacts with moisture vapor in the air, it is generally obtained by adding in the form of calcium carbonate or calcium hydroxide, then making it CaO in the process of heating at high temperature.
FIG. 5 is a diagram showing the chemical composition range of mixture α-sialon phosphor (range sandwiched by two triangles indicated by oblique lines) and the chemical composition range of entire powder.
As shown in FIG. 5, the chemical composition range of mixture α-sialon phosphor is that sandwiched by two triangles indicated by oblique lines in a triangular pyramid composition range with a peak of silicon nitride. The amount of metal dissolved in α-sialon exactly produced is (x+y)>0.3, which is an amount needed to stabilize the structure of α-sialon as described earlier. In a composition range with less addition amount than this, the mixture α-sialon phosphor is composed of α-sialon with composition of (x+y)>0.3, β-sialon with rare-earth metal not dissolved and unreacted silicon nitride.
In general, a small amount of glass phase (less than 5%) is further included.
The third phosphor is represented by; La1-XSi3N5:xCe (doping amount x is 0<x<1), where lanthanum site is replaced in solid dissolution by cerium ion activator. If the doping amount is 0.1<x<0.5, it is ultraviolet light excitation phosphor and, if the doping amount is 0.0<x<0.2, it is electron beam excitation phosphor.
The cerium ion doped lanthanum silicon nitride phosphor is, as described later, synthesized using e.g. reaction sintering furnace on the conditions of 1800 to 2200° C., under nitrogen pressure at 5 to 20 and 1 to 10 hours, preferably of 1850 to 1950° C., under nitrogen pressure at 5 to 10 atm and 1 to 2 hours.
According to use object, use conditions etc., the concentration of phosphor in light transmitting material can be changed. For example, the amount of phosphor may be changed continuously or stepwise according to nearing to the light emitting element. In this case, the phosphor concentration may be increased at part close to the light emitting element Thereby, light generated from the light emitting element can be efficiently radiated toward the phosphor. On the contrary, the phosphor is likely subjected to heat generated from the light emitting element and the degradation of phosphor may occur. On the other hand, when the phosphor concentration is reduced according to nearing to the light emitting element the degradation of phosphor due to heat generated from the light emitting element can be prevented.
The composite material of phosphor dispersed in plastics or glass can, by itself, compose a phosphor layer by forming into a desired shape. When it is formed into a plate, the amount of emission light wavelength-converted by phosphor can be controlled by the thickness of plate. Thus, by using the is composite material of phosphor dispersed in plastics or glass, the mixed light of light emitted from light emitting element and light radiated from phosphor can be easily adjusted with high precision.
Phosphor 36 of the embodiment is positioned to be radiated from light emitting element and radiates light. Namely, part of light emitted from the light emitting element is wavelength-converted by the phosphor. Thereby, light with a different wavelength (emission color) from that of the light emitting element is generated. The wavelength-converted light is mixed with light not wavelength-converted by phosphor.
Therefore, the entire light emitting apparatus offers light with different color from that of the light emitting element. Meanwhile, the emission color can be changed by controlling the composition of phosphor. Thereby, the emission color of the entire light emitting apparatus can be adjusted.
The p-electrode 18 and n-electrode 19 of light emitting element 10 are wire-bonded through the wires 40 and 41 to the lead frames 30 and 31, respectively. Thereafter, the light emitting element 10, part of lead frames 30, 31, and wires 60, 41 are sealed by sealing resin 50 composed of epoxy resin. The material of sealing resin 50 is not limited to epoxy resin, if it is transparent, and may be preferably silicon resin, urea resin or glass. Considering adhesion, refractive index etc. in case that the sealing resin 50 contacts the phosphor resin it is preferably of the same material as the phosphor resin 35.
Although the sealing resin 50 is provided to protect the device structure, the shape of sealing resin 50 may be changed to allow the sealing resin 50 to have lens effect according to use object. For example, it is formed into concave lens type, convex lens type etc. other than the lamp type shown in FIG. 1, Further, the shape of sealing resin 50 viewed from the direction of light extraction (from above in FIG. 1) may be formed circular, elliptic or rectangular. Phosphor 36 may be also dispersed in the sealing resin 50 regardless of the previous case that the phosphor resin 35 is omitted.
FIGS. 6A and 6B are circuit diagrams showing rectifier circuits used in the first embodiment LED 1 can be driven with pulsed current. Thereby, light from light emitting element 10 and light from phosphor 36 are taken out in time division and therefore the emission color of LED 1 can be adjusted. AC current can be supplied to LED 1 by using the full-wave rectifier circuit in FIG. 6A or the half-wave rectifier circuit in FIG. 6B.
FIG. 10 is a cross sectional view showing a chip-type LED as a light emitting apparatus in the second preferred embodiment according to the invention. Like components are indicated by same numerals used in lamp-type LED 1 of the first embodiment, LED 2 shown in FIG. 10 also emits white light like the lamp-type LED 1 and can be applied to, for example, a planar light source and a linear light source in combination with a light guiding member, and further applied to various display devices.
FIG. 14 is a cross sectional view showing a reflection-type LED 6 as a light emitting apparatus in the third preferred embodiment according to the invention. Like components are indicated by same numerals used in the lamp-type LED 1 of the first embodiment.
As shown in FIG. 11, the reflection-type LED 6 has a reflection mirror 110 on concave surface 111 of which phosphor layer 112 is formed. The phosphor layer 112 is of epoxy resin including phosphor 36 and is formed by coating. It may be of light transmitting material such as silicon resin and urea resin, other than epoxy resin and may be formed by vapor deposition, printing etc., other than coating. The phosphor layer may be formed on convex surface 113 of the reflection mirror 110. In this case, the reflection mirror 110 is formed using a light transmitting material and the surface of phosphor layer is mirrored. The mirroring is conducted forming a layer of metal with high reflection efficiency by vapor deposition, plating etc.
In LED 6 thus structured, part of light from the light emitting element 10 is absorbed and wavelength-converted by phosphor 36 in phosphor layer 112 when it is reflected on the reflection mirror 110. Light thus wavelength-converted is mixed with light reflected without being wavelength-converted, and white light is thereby obtained from the entire LED 6. In LED 6, instead of forming the phosphor layer 112, the light emitting element 10 and reflection mirror 110 may be sealed with a light transmitting material including phosphor. Alternatively, LED 6 may use a phosphor glass with a shape of reflection mirror. In this case, convex surface or the reflection mirror is mirrored. The method of mirroring is the same as described above. Furthermore, a light emitting element may be employed that has a phosphor layer as shown in FIG. 7A, 7E, 9A or 9B. In this case, the phosphor layer 112 on the surface of reflection mirror can be omitted.
FIG. 15A is a side view showing a planar light source 7 as a light emitting apparatus in the fourth preferred embodiment according to the invention. FIG. 15B is a top view (from phosphor layer side) showing the planar light source 7 in FIG. 15A.
Although in this embodiment one side is used as the light introducing surface 123, a plurality of light introducing surfaces maybe provided. Namely, LED's 115 are disposed facing the plurality of light introducing surfaces to introduce light from there. With such a structure, the amount of planar light radiated can be increased. Also, light can be radiated from the light emitting surface with a wider area. Further, the amount of light radiated can be uniformed over the entire light emitting surface.
FIG. 17A is a side view showing a planar light source 8 as a light emitting apparatus in the fifth preferred embodiment according to the invention. FIG. 17B is a top view (from phosphor layer side) showing the planar light source 8 in FIG. 17B. Like components are indicated by same numerals used in FIGS. 15A and 15B.
FIG. 18 is a side view showing a planar light source 9 using color conversion filter 130 as a light emitting apparatus in the sixth preferred embodiment according to the invention.
The phosphor layer 131 is of transparent base material, such as epoxy resin, silicon resin and urea resin, with phosphor 36 dispersed therein. The transparent sheet 132 is of PET. It is preferred that the phosphor layer 131 has fine uneven profiles on its surface. They serve to familiarize the surface of color conversion sheet 135 (surface of phosphor layer 131) with glass etc. provided on the color conversion 135, Thereby, the occurrence of blur at the interface can be prevented. Also, it is preferred that fine uneven profiles are provided at the bonding surface of transparent sheet 132 to the light guiding layer 137. Thus, by avoiding tight contact between the color conversion sheet 135 and light guiding layer 137, the occurrence of blur at the interface can be prevented.
The light guiding layer 137 is of epoxy resin. It may be of another transparent resin such as silicon resin. The light guiding layer 137 has a reflection film 139 on its lower surface. Thereby, light leakage from the lower surface of light guiding layer 137 can be prevented. The material of reflection layer 139 is not limited to this it is preferred that like reflection layers are provided at side faces except for a face facing LED 115. Thereby, light leakage from the side faces can be prevented. The reflection layer 139 may be omitted.
LED 115 is placed facing the side face of color conversion filter 130. LED 11S may be placed facing the lower surface of color conversion filter 130. In tshis case, the reflection layer 139 is not provided on the lower surface of light guiding layer 137.
FIG. 19 is an illustration showing a cap-type LED 140 as a light emitting apparatus in the seventh preferred embodiment according to the invention.
FIG. 20 is an illustration showing a bulb-type light source 150 as a light emitting apparatus in the eighth preferred embodiment according to the invention.
FIG. 25A is a front view showing a display 200 in the eighth preferred embodiment according to the invention. FIG. 25B is a cross sectional view cut along the line A-A in FIG. 25A. FIG. 26 is a cross sectional view showing a modification of the display 200 cut along the line A-A in FIG. 25A.
FIG. 27 is an enlarged partial front view showing a display 210 using LED 1 in the ninth preferred embodiment according to the invention. FIG. 28 is a block diagram showing a displaying circuit used in the display 210.
FIG. 29 is a front view showing a vehicle traffic light 300 using the chip-type LED 2 in the tenth preferred embodiment according to the invention.
The traffic light 300 has displaying portion 302 in which a plurality of chip-type LED's 2 are arranged in matrix 301 is housing. A colored transparent cover (not shown) is provided on the surface of displaying portion 302. Each LED 2 turns on by control of control means (not shown) to emit white light, which is recognized being colored when transmitting through the colored transparent cover.
Examples of phosphor 36 used in the invention are described below.
Example 1 Preparation of Single-Phase α-Sialon
Examples (1-1) to (1-2) relate to preparation of single-phase α-sialon phosphor.
In preparing single-phase α-sialon phosphor, a ball mill apparatus (Fliche, planetary mill) is used to mix eight raw powders below. The mole ratio of chemical reagents in raw powder is described below (1) to (8).
(1) Ca-α-sialon (Ca0.75Si0.75Al2.25N15.25O0.75)
silicon nitride (Si3N4): aluminum nitride (AlN): calcium oxide (CaO)=13:9:3
(2) Eu-α-sialon (Eu0.5Si9.75Al2.25N15.25O0.75)
silicon nitride (Si3N4): aluminum nitride (AlN): europium oxide (Eu2O3)=13:9:1
(3) Pr-α-sialon (Pr0.6Si9.75Al2.25N15.25O0.75)
silicon nitride (Si3N4): aluminum nitride (AlN): praseodymium oxide (Pr6O11)=30:27:1
(4) Tb-α-sialon (Tb0.5Si9.75Al2.25N15.25O0.75)
silicon nitride (Si3N4): aluminum nitride (AlN): terbium oxide (Tb4O7)=26:18:1
(5) Dy-α-sialon (Dy0.5Si9.75Al2.25N15.25O0.75)
silicon nitride (Si3N4) aluminum nitride (AlN) dysprosium oxide (Dy2O3)=13:9:1
(6) Y-α-sialon (Y0.5Si9.75Al2.25N15.25O0.75)
silicon nitride (Si3N4): aluminum nitride (AlN): yttrium oxide (Y2O3)=13:9:1
(7) Yb-α-sialon (Yb0.5Si9.75Al2.25N15.25O0.75)
silicon nitride (Si3N4) aluminum nitride (AlN); ytterbium oxide (Yb2O3)=13:9:1
(8) Er-α-sialon (Er0.5Si9.75Al2.25N15.25O0.75)
silicon nitride (Si3N4): aluminum nitride (AlN): erbium oxide (Er2O3)=13:9:1
Then, using the above raw powders (1) and (2), seven Eu2+ doped Ca α-sialon phosphors with different doping ratios are prepared as below [1] to [7]. In preparation, the raw powders (1) and (2) are mixed at molar ratios below, then reacted using hot pressing apparatus (Nisshingiken-sha, NEV-HP3) at a pressure of 20 MPa in nitrogen atmosphere (1 atm) of 1700° C. for one hour.
[1] Ca (0% Eu)-α-sialon phosphor (Ca0.75Si9.75Al2.25N15.25O0.75)
only Ca-α-sialon (1) is used.
[2] Ca (5% Eu)-α-sialon phosphor
(Ca0.75Eu0.05Si9.75Al2.25N15.25O0.75)
Ca-α-sialon (1): Eu-α-sialon (2)=95:5
[3] Ca (10% Eu)-α-sialon phosphor
(Ca0.06Eu0.10Si9.75Al2.25N15.25O0.75)
Ca-α-sialon (1): Eu-α-sialon (2)=90:10
[4] Ca (20% Eu)-α-sialon phosphor
(Ca0.60Eu0.10Si9.75Al2.25N15.25O0.75)
Ca-α-sialon (1): Eu-α-sialon (2)=80:20
[5] Ca (30% Eu)-α-sialon phosphor
(Ca0.63Eu0.15Si9.75Al2.25N15.25O0.75)
Ca-α-sialon (1): Eu-α-sialon (2)=70.30
[6] Ca (50% Eu)-α-sialon phosphor
(Ca0.38Eu0.25Si9.75Al2.25N15.25O0.75)
Ca-α-sialon (1): Eu-α-sialon (2)=50:50
[7] Ca (70% Eu)-α-sialon phosphor
(Ca0.23Eu0.35Si9.75Al2.25N15.25O0.75)
Ca-α-sialon (1): Eu-α-sialon (2)=30:70
As shown, it is found that any excitation spectra have broad peaks at 280 and 400-450. In the two peaks, the peak intensity increases according to increase in doping ratio until reaching Eu2− doping ratio of 50%. When doping ratio exceeds 50%, the peak intensity lowers due to concentration quenching. However, it is still higher than doping ratio of 30%.
Of the two peaks found in the spectra, peak of 280 nm belongs to excitation peak of Ca-α-sialon, matrix material, and peak of 400-450 nm belongs to charge transfer absorption band of Eu—(N or O). The latter Eu—(N or O) charge transfer absorption band peak shifts to longer wavelength side according to increase in Eu2+ doping ratio. Therefore, it can be excited by emission light (450 to 550 nm) of InGaN system blue LED.
The reason why the Eu2+ ion doped Ca-α-sialon phosphor has still higher emission intensity is, as described earlier, that distance between Eu2+ ions doped is as far as about 5 angstroms. Namely, since the distance between between Eu2+ ions doped is relatively big, the emission intensity does not so rapidly lowers even when the amount of Eu2+ ions doped increases. Thus, it is less subject to concentration quenching.
Next, raw powders of Ca-α-sialon (1) and Pr-α-sialon (3) are mixed at molar ratio of 50:50, then reacted using hot pressing apparatus (Nisshingiken-sha, REV-HP3) at a pressure of 20 MPa in nitrogen atmosphere (1 atm) of 1700° C. for one hour. Thereby, Pr3+ ion doped Ca-α-sialon phosphor (Ca0.38Eu0.25Si9.75Al2.25N15.25O0.75) is synthesized.
Next, raw powders of Ca-α-sialon (1) and Tb-α-sialon (4) are mixed at molar ratio of 50:50, then reacted using hot pressing apparatus (Nisshingiken-sha, NEV-HP3) at a pressure of 2 MPa in nitrogen atmosphere (1atm) of 1700° C. for one hour Thereby, Tb3+ ion doped Ca-α-sialon phosphor (Ca0.38Tb0.25Si9.75Al2.25N15.25O0.75) is synthesized.
Next, raw powders of Ca-α-sialon (1), Eu-α-sialon (2) and Dy-α-sialon (5) are mixed at molar ratio of 50:40:10, then reacted using hot pressing apparatus (Nisshingiken-sha, NEV-HP3) at a pressure of 20 MPa in nitrogen atmosphere (1 atm) of 1700° C. for one hour. Thereby, Eu2− and Dy3+ ion co-doped Ca-α-sialon phosphor (Ca0.38Eu0.20Dy0.05Si9.75Al2.25N15.25N15.25O0.75) is synthesized.
FIGS. 34A and 34B are spectrum diagrams showing excitation spectrum and emission spectrum, respectively, of Eu2+ and Dy3− ion co-doped Ca-α-sialon phosphor.
As shown in FIG. 34A, in the excitation spectrum, two broad peaks at 290 nm, 450 nm are observed. Of the two peaks, peak of 290 nm belongs to excitation peak of Ca-α-sialon, matrix material, and peak of 450 nm belongs to charge transfer absorption band of Eu—(N or O). As shown in FIG. 34B, in the emission spectrum, only one peak based on d-f transition of Eu2+ ion is observed.
Next, raw powders of Y-α-sialon (6) and Eu-α-sialon (2) are mixed at molar ratio of 95:5, then reacted using hot pressing apparatus (Nisshingiken-sha, NEV-HP3) at a pressure of 20 MPa in nitrogen atmosphere (1 atm) of 1700° C. for one hour. Thereby, Eu2+ ion doped Y-α-sialon phosphor (Y0.38Eu0.02Si9.75Al2.25N15.25O0.75) is synthesized.
Further, since the rare-earth element doped oxide nitride phosphor has α-sialon as matrix material, it has excellent mechanical and thermal properties and excellent chemical stability. Therefore, the rare-earth element doped oxide nitride phosphor can be stably operated even in severe environment. i.e., it has excellent weather resistance.
Another example of single-phase α-sialon phosphor is prepared as Samples A to G and K to N in Example (2-5) described later, and the fluorescent properties are measured.
Example 2 Preparation of Mixed α-Sialon Phosphor
Examples (2-1) to (2-5) relate to preparation of mixed α-sialon phosphor.
Example (2-1)
A mixture of Si3N4:Eu2O3:CaO:AlN=79.0:1.5:2.2:15.8 (molar ratio) (where calcium carbonate is added as CaO) is molded in a 10 mm diameter mold at 200 kg/cm2. Then, it is hot-press sintered at a pressure of 20 MPa in nitrogen atmosphere (1 atm) of 1700° C. for one hour. After the heating, the sintered body is powdered. As the result of powder X-ray diffraction analysis (Rigaku-sha, RINT2200), a material of 66 weight α-sialon, 18 weight % β-sialon and 15 weight % unreacted α-silicon nitride is obtained.
The entire powder composition is represented by α-sialon composition formula: (Ca0.11, Eu0.14)(Si, Al)12(O, N)16.
As shown by (1) in FIG. 38, in the excitation spectrum, a peak at around 300 nm belongs to excitation of matrix Ca-α-sialon, and a peak at 300-500 nm belongs to charge transfer absorption band of Eu—(O, N). Therefore, it can be excited by, emission light of InGaN system blue LED (450 to 550 nm). As shown by (1) in FIG. 39, in the emission spectrum, a peak at around 580 nm is observed.
Example (2-2)
A mixture of Si3N4:Eu2O3:CaO: AlN: Al2O3=75.9:1.0:3.2:17.2:1.72 (molar ratio) (where calcium carbonate is added as CaO) is molded in a 10 mm diameter mold at 200 kg/cm2. Then, it is heated in argon atmosphere of 1750° C. for two hours. After the heating, the sintered body is powdered As the result of powder X-ray diffraction analysis (Rigaku-sha, RINT2200), a material of 68 weight % α-sialon, 24 weights β-sialon and 8 weight % unreacted α-silicon nitride is obtained.
As shown by (2) in FIG. 38, in the excitation spectrum, a peak at around 350-500 nm is observed. As shown by (2) in FIG. 39, in the emission spectrum a peak at around 550-650 nm is observed.
Example (2-3)
A mixture of Si3N4:Tb2O3:CaO:AlN=79.0:1.5:2.2:15.8 (molar ratio) (where calcium carbonate is added as CaO) is molded in a 10 mm diameter mold at 200 kg/cm2. Then, it is heated in nitrogen atmosphere of 1700° C. for two hours. After the heating, the sintered body is powdered. As the result of powder X-ray diffraction analysis (Rigaku-sha, RINT2200), a material of 68 weight % α-sialon, 16 weight % β-sialon and 16 weight % unreacted α-silicon nitride is obtained.
The entire powder composition is represented by α-sialon composition formula: (Ca0.11, Tb0.14)(Si, Al)12(O, N)16.
The material has main peaks at around 400 nm and 540 nm.
Example (2-4)
A mixture of Si3N4: Yb2O3:CaO:AlN:Al2O3=75.9:1.0:3.2:17.2:1.72 (molar ratio) (where calcium carbonate is added as CaO) is molded in a 10 mm diameter mold at 200 kg/cm2. Then, it is heated in nitrogen atmosphere of 1750° C. for two hours. After the heating, the sintered body is powdered. As the result of powder X-ray diffraction analysis (Rigaku-sha. RINT2200), a material of 70 weight % α-sialon, 22 weights % β-sialon and 8 weight % unreacted α-silicon nitride is obtained.
The entire powder composition is represented by α-sialon composition formula: (Ca0.15, Yb0.06)(Si, Al)12(O, N)16.
Example (2-5)
Next, various Ca-α-sialon:Eu2+ phosphors are prepared and the fluorescent properties are measured. Samples A to G are single-phase α-sialon phosphors and Samples X to N are mixed α-sialon phosphors.
In preparing Ca-α-sialon:Eu2+ phosphor, starting materials, CaO, Si3N4, AlN, Al2O3 and Eu2O3 are weighed to have a given ratio, then wet-mixed with acetone. The mixed material powder is filled into Mo container, which is made using 0.1 mm thick Mo (module) plate. Then, it is sintered using RF is induction heater in argon atmosphere of 100-1750° C., atmospheric pressure for two hours, as shown by temperature profile in FIG. 40.
FIG. 41 is a table showing the composition (molar ratio) of Samples A to N, Ca-α-sialon:Eu2+ phosphors. FIG. 42 is a table showing atom % of Samples A to N. Ca-α-sialon:Eu2+ phosphors. In FIGS. 41 and 42, ※3015 means m=3.0 and n=1.5 in general formula of Ca-α-sialon; C0.5mSi12−(m+n)Al(m+n)O nN6−n. In like manner, 2010 means m=2.0 and n=1.0, 1005 means m=1.0 and n=0.5, 3030 means m=3.0 and n=3.0, 2015 means m=2.0 and n=1.5, 05025 means m=0.5 and n=0.25, 0505 means m=0.5 and n=0.5 and 2613 means m=2.6 and n=1.3. Also, Bu/Ca means element ratio, and Eu % means Eu replacement ratio to all Ca sites. In atom %, each element numerical ratio is indicated assuming the number of all atoms to be 100.
In Samples A, B and C, Eu2O3 is made 3.0 mol % of the entire composition and m, n are changed. The excitation spectra are shown in FIG. 43 and the emission spectra are shown in FIG. 46.
In Samples X, L, M and N, Eu2O3 is made 1.0 to 1.2 mol % of the entire composition and m, n are changed. Sample K has the same m, n values as Sample A and less Eu content than it. Samples M, N have the same m, n values as Sample B and less Eu content than it. Sample L has m, n values in between those of Samples K and M. The excitation spectra are shown in FIG. 51 and the emission spectra are shown in FIG. 52.
FIG. 53 is a spectrum diagram showing excitation spectra of Samples A to J FIG. 54 is a spectrum diagram showing emission spectra of Samples A to J. FIGS. 53 and 54 are provided to facilitate the comparison in fluorescent property between Samples A to J.
Since Ca-α-sialon is defined by the general formula: Ca0.5mSi12−(m+n)Al(m+n)OnN6−n, to increase m value means that the content of Ca, Al increases and the content of Si decreases. To increase n value means that N/O ratio decreases and the content of Si decreases. Also, since CaO is used as raw material, it is necessary that the relation of m and n satisfies 2m≦n. So, if Ca content is fixed, N/O ratio becomes maximum when 2 m=n.
4. With regard to the excitation spectra, it its assumed that there are peaks at around 300, 390 and 450. However, peak at around 300 nm does not change in all samples. On the other hand, there is a tendency that the peak intensity ratio at around 400 and 450 nm depends on Eu content to the entire composition and more the Eu content is, higher the intensity at around 450 nm is.
Example 3 Preparation of Cerium Ion Doped Lanthanum Silicon Nitride Phosphor
LaN, CeN and Si3N4 are used as raw material powder, weighed to have a molar ratio of LaN:CeN:Si3N4=0.7:0.3:1.0. These powders are mixed in a mortar inside a glove box of argon atmosphere. Mixture powder obtained is formed into pellet, then sintered in nitrogen atmosphere of 10 atm, 1900° C. for two hours by using a reaction sintering furnace. Thereby, La0.7Si3N5:0.3Ce is synthesized.
As shown in FIG. 55B, in La0.7Si3N5:0.3Ce, blue emission is observed at 440 nm, 470 nm under ultraviolet ray radiation of 358 nm. In general, Ce3+ ion gives emission based on the f-d transition of (5d) excitation state to (4f) ground state. Therefore, it is assumed that blue emission observed belongs to transition of 2T2 (5d1)→2F5/2 (4f1) in Ce3+ ion. Namely, assuming that nine N atoms located at Ce3+ ion in La0.7Si3N5:0.3Ce form three-dimensional crystal filed to Ce3+ ion, 5d orbital energy of Ce3+ ion is split into 2E and 2T2. Further, by spin orbit interaction, 2T2 with low energy level is split into T7 and T5. 4f orbital energy is split into 2F5/2 and 2F7/2 by spin orbit interaction.
[3] LaN:CeN:Si3N4=0.5:0.5.1.0, and
[4] LaN:CeN:Si3N4=0.9:1.0:10.
These powders are mixed in a mortar inside a glove box of argon atmosphere. Mixture powder obtained is formed into pellet, then sintered in nitrogen atmosphere of 10 atm, 1900° C. for two hours by using a reaction sintering furnace. Thereby, La1-xSi3N5:xCe (x=0.1, 0.3, 0.5 and 1.0) is synthesized.
FIG. 56 is a graph showing blue emission intensity, which belongs to transition of 2T2(5d1)→2F5/2(4f1) (at 440 nm) in Ce3+, ion, depending on the ratio of Ce3+ ion doped in solid solution replacement to La3+ site of LaSi3N5.
As shown in FIG. 56, the blue emission intensity increases until the ratio (x) of Ce3+ ion doped reaches 0.3. When exceeding 0.3, the blue emission intensity lowers due to concentration quenching. Viewing from this result, it is understood that, in La1-xSi3N5:xCe, 0.1<x<0.5 is suitable to offer ultraviolet ray excitation phosphor.
[2] LaN:Cen:Si3N4=0.5:0.5.1.0,
[3] LaN:Cen:Si3N4=0.6:0.41.0,
[6] LaN:Cen:Si3N5=0.9:0.1:1.0.
These powders are mixed in a mortar inside a glove box of argon atmosphere. Mixture powder obtained is formed into pellet, then sintered in nitrogen atmosphere of 10 atm, 1900° C. for two hours by using a reaction sintering furnace. Thereby, La1−xSi3N5:xCe (x=0.6, 0.5, 0.4, 0.3, 0.2 and 0.1) is synthesized.
As shown in FIG. 57, even when the ratio (x) of Ce3+ ion doped lowers from 0.6 to 0.1, the cathode luminescence intensity increases. Viewing from this result, it is understood that, in La1-xSi3N5:xCe, 0.0<x<0.2 is suitable to offer electron beam excitation phosphor applicable to VED or FED.
In the cathode luminescence spectra in FIG. 57, which is slightly different from that in FIG. 55B, there is observed an emission that belongs to three transitions of 2T2(5d1): 2T2(5d1)→2F5/2T7(4f1), 2T2(5d1)→2F5/2(4f1) and 2T2 (5d1) →2F7/2 (4f1). This is assumed because, according as the ratio of Ce3+ ion doped changes, configuration environment around Ce3+ ion changes, thereby the emission intensity of Ce3+ ion, which belongs to transitions of 2T2(5d1)→2F5/2T7 (4f1) and 2T2(5d1)→2F5/2T5(4f1) in Ce3+ ion, changes.
The details of synthetic method, conditions of La1-xSi3N5:xCe are not limited to that described above and may be modified variously.
In Brief, the light emitting apparatus in preferred embodiments of the invention is structured as follows (1) to (21),
(1) in claim 3 attached herein, the light emitting element is mounted on a cup portion of lead frame, and a light transmitting material containing the phosphor is filled in the cup portion.
(2) in claim 3 attached herein, the light emitting element is mounted on a cup portion of lead frame, and a phosphor layer composed of a light transmitting material containing the phosphor is formed on the surface of the light emitting element.
(3) in claim 3 attached herein, the light emitting element is mounted on a cup portion of a lead frame, and the light emitting element and part of lead frame are covered with a light transmitting material containing the phosphor.
(4) in claim 3 attached herein, the light emitting element is mounted on a substrate, and a phosphor layer composed of a light transmitting material containing the phosphor is formed on the surface of the light emitting element.
(5) in claim 3 attached herein, the light emitting element is mounted on a substrate, and the light emitting element is sealed with a of a light transmitting material containing the phosphor.
(6) in claim 3 attached herein, the light emitting element is mounted on a cup portion provided on a substrate, and a light transmitting material containing the phosphor is filled in the cup portion.
(7) in claim 3 attached herein, the light emitting element is mounted on a cup portion provided on a substrate, and a phosphor layer composed of a light transmitting material containing the phosphor is formed on the surface of the light emitting element.
(8) in claim 3 attached herein, a phosphor layer composed of a light transmitting material containing the phosphor is formed on the surface of the substrate of the light emitting element.
(9) in the light emitting apparatus (8), a phosphor layer composed of a light transmitting material containing the phosphor is also formed on the side of the light emitting element.
(10) in claim 4 attached herein, a phosphor layer composed of the phosphor is formed on the surface of the substrate of the light emitting element.
(11) in the light emitting apparatus (10), a phosphor layer composed of the phosphor is also formed on the side of the light emitting element.
(12) in claim 3 attached herein, a reflection plate is provided in the emission direction of the light emitting element.
(13) in the light emitting apparatus (12), a phosphor layer composed of a light transmitting material containing the phosphor is formed on the surface of the reflection plate to face the light emitting element.
(14) in claim 4 attached herein, a reflection plate is provided in the emission direction of the light emitting element.
(15) in the light emitting apparatus (14), the reflection plate is of the phosphor, and the reflection plate includes a mirrored surface opposite to its surface facing the light emitting element.
(16) in claim 3 attached herein, a phosphor layer composed of a light transmitting material containing the phosphor is provided in the emission direction of the light emitting element.
(17) in claim 4 attached herein, a phosphor layer composed of the phosphor is provided in the emission direction of the light emitting element.
(18) in the light emitting apparatus (16) or (17), a light guiding member composed of light introducing surface and light emitting surface is further provided, the light emitting element is disposed facing the light introducing surface of the light guiding member, and the phosphor layer is disposed between the light emitting element and the light introducing surface of the light guiding member.
(19) in the light emitting apparatus (16) or (17), a light guiding member composed of light introducing surface and light emitting surface is further provided, the light emitting element is disposed facing the light introducing surface of the light guiding member, and the phosphor layer is disposed on the light emitting surface side of the light guiding member.
(20) in the light emitting apparatus (19), a layer of light transmitting material is further provided between the light guiding member and the phosphor layer.
(21) in any one of the light emitting apparatuses (1) to (20), the light emitting element is III group nitride system compound semiconductor light emitting element.
As described above, in the invention, LED 1 is structured such that the light emitting element 10 is mounted through adhesive 20 on the cup portion 33 provided on the lead frame 30, the wires 40, 41 connected to the lead frames 30, 31 are bonded to the p-electrode and n-electrode of the light emitting element 10, epoxy resin 35 with phosphor 36 dispersed therein is filled in the cup portion 33, and the light emitting element 10, part of lead frames 30, 31 and wires 40, 41 are sealed with sealing resin 50 of epoxy resin. In LED 1, the emission wavelength of the light emitting element 10 is in the range of 360 to 550 nm, phosphor 36 is of rare-earth element doped oxide nitride phosphor or cerium ion doped lanthanum silicon nitride phosphor, and part of light from the light emitting element 10 is wavelength-converted. Thereby, red color (color rendering property of red) can be enhanced as compared to that of conventional white LED. Also, with same system phosphor, green to red can be expressed and therefore it is very advantageous to color mixture.
US6776927 * Apr 8, 2003 Aug 17, 2004 National Institute For Materials Science Oxynitride phosphor activated by a rare earth element, and sialon type phosphor
US7135713 * Jul 22, 2004 Nov 14, 2006 Epitech Technology Corporation Light emitting diode and method for manufacturing the same
US7382033 * Dec 19, 2003 Jun 3, 2008 Toyoda Gosei Co., Ltd. Luminescent body and optical device including the same
US7408203 * Apr 13, 2005 Aug 5, 2008 Lg Electronics Inc. Light emitting device and fabrication method thereof and light emitting system using the same
US7608862 * Mar 1, 2005 Oct 27, 2009 Fujikura Ltd. Light emitting device and a lighting apparatus
US7815817 Mar 20, 2006 Oct 19, 2010 National Institute For Materials Science Phosphor and process for producing the same
US7846351 Mar 20, 2006 Dec 7, 2010 National Institute For Materials Science Fluorescent substance, process for producing the same, and luminescent device
US7910023 Apr 27, 2006 Mar 22, 2011 National Institute For Materials Science Lithium-containing sialon phosphor and method of manufactring the same
US7973402 * Sep 9, 2009 Jul 5, 2011 Dialight Corporation LED light using phosphor coated LEDs
US7981321 * Jun 28, 2006 Jul 19, 2011 Koninklijke Philips Electronics N.V. Illumination system comprising a yellow green-emitting luminescent material
US8134165 * Aug 14, 2008 Mar 13, 2012 Seoul Semiconductor Co., Ltd. Light emitting device employing non-stoichiometric tetragonal alkaline earth silicate phosphors
US8147067 * Sep 26, 2006 Apr 3, 2012 Koninklijke Philips Electronics N.V. Laser projection system based on a luminescent screen
US8148746 * Sep 27, 2007 Apr 3, 2012 Rohm Co., Ltd. Semiconductor light emitting device
US8277686 * Dec 22, 2005 Oct 2, 2012 Ube Industries, Ltd. Sialon phosphor particles and production method thereof
US8310618 * Jan 14, 2011 Nov 13, 2012 Lg Innotek Co., Ltd. Image display apparatus and method of manufacturing the same with a slim thickness
US8628687 Sep 12, 2012 Jan 14, 2014 Ube Industries, Ltd. Sialon-based oxynitride phosphor and production method thereof
US8685279 Mar 8, 2013 Apr 1, 2014 Denki Kagaku Kogyo Kabushiki Kaisha Sialon phosphor, process for producing the same, and illuminator and luminescent element employing the same
US8765015 * Mar 22, 2012 Jul 1, 2014 National Institute For Materials Science Phosphor, process for producing the same, and luminescent device
US8878219 * Jan 11, 2008 Nov 4, 2014 Cree, Inc. Flip-chip phosphor coating method and devices fabricated utilizing method
US9041045 * Feb 25, 2011 May 26, 2015 Sung-Bok Shin Transparent LED wafer module and method for manufacturing same
US9157026 * Oct 4, 2010 Oct 13, 2015 Lg Innotek Co., Ltd. Photoluminescent sheet
US9343630 * Mar 12, 2010 May 17, 2016 Toyoda Gosei Co., Ltd. Semiconductor light emitting element
US20050001226 * Jul 22, 2004 Jan 6, 2005 Shi-Ming Chen Light emitting diode and method for manufacturing the same
US20050194604 * Mar 1, 2005 Sep 8, 2005 Fujikura Ltd., National Institute For Material Science Light emitting device and a lighting apparatus
US20050230692 * Apr 13, 2005 Oct 20, 2005 Lg Electronics Inc. Light emitting device and fabrication method thereof and light emitting system using the same
US20060163683 * Dec 19, 2003 Jul 27, 2006 Gundula Roth Luminescent body and optical device including the same
US20060232725 * May 27, 2005 Oct 19, 2006 Chua Janet B Y Use of a wavelength converting material to project an image or backlighting through a display panel, and backlight for exciting same
US20070248519 * Jun 14, 2005 Oct 25, 2007 National Institute For Materials Science Alpha-Siaion Powder and Method for Producing the Same
US20070278502 * Sep 12, 2005 Dec 6, 2007 Rohm Co., Ltd. Semiconductor Light Emitting Device
US20080203896 * Aug 7, 2007 Aug 28, 2008 Jae-Kwang Ryu Light emission device and display device provided with the same
US20080259431 * Sep 26, 2006 Oct 23, 2008 Koninklijke Philips Electronics, N.V. Laser Projection System Based on a Luminescent Screen
US20080309220 * Dec 22, 2005 Dec 18, 2008 Ube Industries, Ltd. Sialon Phosphor Particles and Production Method Thereof
US20090057611 * Mar 20, 2006 Mar 5, 2009 National Institute For Materials Science Phosphor and process for producing the same
US20090236969 * Mar 20, 2006 Sep 24, 2009 National Institute For Materials Science Fluorescent substance, process for producing the same, and luminescent device
US20090284948 * Jun 29, 2007 Nov 19, 2009 Ube Industries, Ltd., A Corporation Of Japan Sialon-based oxynitride phosphor and production method thereof
US20100072496 * Sep 27, 2007 Mar 25, 2010 Rohm Co., Ltd. Semiconductor light emitting device
US20100072498 * Apr 27, 2006 Mar 25, 2010 National Institute For Materials Science Lithium-containing sialon phosphor and method of manufactring the same
US20100079058 * Jun 28, 2006 Apr 1, 2010 Koninklijke Philips Electronics, N.V. Illumination system comprising a yellow green-emitting luminescent material
US20100237381 * Mar 12, 2010 Sep 23, 2010 Toyoda Gosei Co., Ltd. Semiconductor light emitting element
US20100289047 * Nov 28, 2008 Nov 18, 2010 Kyocera Corporation Light Emitting Element and Illumination Device
US20110199288 * Jan 14, 2011 Aug 18, 2011 Dong Wook Park Image display apparatus and method of manufacturing the same
US20110284866 * Jul 26, 2011 Nov 24, 2011 Tran Chuong A Light-emitting diode (led) structure having a wavelength-converting layer and method of producing
US20120176568 * Mar 22, 2012 Jul 12, 2012 Naoto Hirosaki Phosphor, process for producing the same, and luminescent device
US20120326120 * Feb 25, 2011 Dec 27, 2012 Wang-Kyun SHIN Transparent led wafer module and method for manufacturing same
US20150085467 * Sep 25, 2014 Mar 26, 2015 Shin-Etsu Chemical Co., Ltd. Red lamp and vehicle lighting fixture
EP1873225A1 * Mar 20, 2006 Jan 2, 2008 National Institute for Materials Science Fluorescent substance, process for producing the same, and luminescent device
EP1873225A4 * Mar 20, 2006 Jan 20, 2010 Nat Inst For Materials Science Fluorescent substance, process for producing the same, and luminescent device
EP2022835A1 * May 8, 2007 Feb 11, 2009 Denki Kagaku Kogyo Kabushiki Kaisha Sialon phosphor, process for producing the same, and illuminator and luminescent element employing the same
EP2022835A4 * May 8, 2007 Oct 5, 2011 Denki Kagaku Kogyo Kk Sialon phosphor, process for producing the same, and illuminator and luminescent element employing the same
EP2036966A4 * Jun 29, 2007 May 4, 2011 Ube Industries Sialon-base oxynitride phosphors and process for production thereof
EP2730635A1 * Jun 29, 2007 May 14, 2014 Ube Industries, Ltd. Sialon-based oxynitride phosphor and production method thereof
EP2966147A1 * Jul 7, 2015 Jan 13, 2016 Nichia Corporation Fluorescent material and light emitting device using same and method for manufacturing fluorescent material
WO2007004138A2 Jun 28, 2006 Jan 11, 2007 Philips Intellectual Property & Standards Gmbh Illumination system comprising a yellow green-emitting luminescent material
WO2007004138A3 * Jun 28, 2006 Mar 22, 2007 Philips Intellectual Property Illumination system comprising a yellow green-emitting luminescent material
WO2009003988A1 * Jun 30, 2008 Jan 8, 2009 Leuchtstoffwerk Breitungen Gmbh Ce3+, eu2+ and mn2+ - activated alkaline earth silicon nitride phosphors and white-light emitting led
U.S. Classification 257/98, 257/102, 257/100, 257/103
International Classification C09K11/79, C09K11/77, C09K11/08, C09K11/80, C09K11/64, H01L33/60, H01L33/56, H01L33/50, H01L33/06, H01L33/62, H01L33/32
Cooperative Classification H01L2924/01019, H01L2924/12041, H01L2924/01025, C04B35/597, H01L33/502, H01L2224/49107, C04B2235/3852, Y02B20/181, C04B2235/3873, C04B2235/3224, C04B2235/80, H01L2924/01079, C09K11/0883, C04B35/584, C04B2235/3217, C04B2235/766, C04B2235/3865, H01L2924/01066, G02F2001/133614, C04B2235/3869, C04B2235/3208, H01L2924/01068, C04B35/6455, C04B2235/3225, C09K11/7734
European Classification C04B35/584, C04B35/645H, C04B35/597, C09K11/08J, C09K11/77N6
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:YOSHIMURA, NAOKI;SUEHIRO, YOSHINOBU;TAKAHASHI, YUJI;AND OTHERS;REEL/FRAME:015757/0210