Patent Grant
8308980
1. Field of the Invention
Embodiments of the present invention relate generally to light emitting devices and, more particularly, to light emitting devices including at least one light-emitting diode and phosphor including lead- and/or copper-containing chemical compounds and converting the wavelength of light.
2. Description of the Related Art
Light emitting devices (LEDs), which used to be used for electronic devices, are now used for automobiles and illumination products. Since light emitting devices have superior electrical and mechanical characteristics, demands for light emitting devices have been increased. In connection to this, interests in white LEDs are increasing as an alternative to fluorescent lamps and incandescent lamps.
In LED technology, solution for realization of white light is proposed variously. Normally, realization of white LED technology is to put the phosphor on the light-emitting diode, and mix the primary emission from the light emitting diode and the secondary emission from the phosphor, which converts the wavelength. For example, as shown in WO 98/05078 and WO 98/12757, use a blue light emitting diode, which is capable of emitting a peak wavelength at 450-490 nm, and YAG group material, which absorbs light from the blue light emitting diode and emits yellowish light (mostly), which may have different wavelength from that of the absorbed light. However, phosphors which are used for white LEDs are usually unstable in the water, vapor or polar solvent, and this unstableness may cause changes in the emitting characteristics of white LED.
One embodiment exemplarily described herein can be generally characterized as a light emitting device that includes a light emitting diode (LED) for emitting light and a phosphor adjacent to the LED. The phosphor is excitable by light emitted by the LED and may include a first compound having a host lattice comprising first ions, silicon and oxygen. A first portion of the first ions may be substituted by divalent copper ions and the first compound may have one of an Olivin crystal structure, a β-K2SO4 crystal structure, a trigonal Glaserite (K3Na(SO4)2) or monoclinic Merwinite crystal structure, a tetragonal Ackermanite crystal structure, a tetragonal crystal structure and an orthorhombic crystal structure.
Another embodiment exemplarily described herein can be generally characterized as a light emitting device that includes a light emitting diode (LED) for emitting light and a phosphor adjacent to the LED. The phosphor is excitable by light emitted by the LED and may include a first compound having a host lattice comprising first ions and oxygen. A first portion of the first ions may be substituted by copper ions and the copper ions do not act as luminescent ions upon excitation with the light emitted by the LED.
Further embodiments of the invention may be apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout, and in which:
Refer to the attached drawing, the wavelength conversion light emitting device is going to be explained in detail, and the light emitting device and the phosphor are separately explained for easiness of explanation as below.
(Light Emitting Device)
Light emitting diodes may emit light with a wide range of wavelengths, for example, from ultraviolet light to visible light. In one embodiment, a UV light emitting diode and/or blue light emitting diode may be used.
Phosphor, i.e., a phosphorescent substance, 3 may be placed on the top and side faces of the light emitting diode 6. In some embodiments, the phosphor may include lead- and/or copper containing chemical compounds. In some embodiments, the chemical compounds may comprise aluminates, silicates, antimonates, germanates, germanate-silicates, phosphates, or the like, or a combination thereof. Phosphor 3 converts the wavelength of the light from the light emitting diode 6 to another wavelength or other wavelengths. In one embodiment, the light is in a visible light range after the conversion. Phosphor 3 may be applied to light emitting diode 6 after mixing phosphor 3 with a hardening resin. The hardening resin including phosphor 3 may also be applied to the bottom of light emitting diode 6 after mixing phosphor 3 with electrically conductive paste 9.
The light emitting diode 6 mounted on substrate 1 may be sealed with one or more sealing materials 10. Phosphor 3 may be placed on the top and side faces of light emitting diode 6. Phosphor 3 can also be distributed in the hardened sealing material during the production. Such a manufacturing method is described in U.S. Pat. No. 6,482,664, which is hereby incorporated by reference in its entirety.
Phosphor 3 may comprise one or more lead- and/or copper containing chemical compounds. Phosphor 3 may include one or more single chemical compounds. Each single compound may have an emission peak of, for example, from about 440 nm to about 500 nm, from about 500 nm to about 590 nm, or from about 580 nm to 700 nm. Phosphor 3 may include one or more single phosphors, which may have an emission peak as exemplified above.
In regard to light emitting device 40, light emitting diode 6 may emit primary light when light emitting diode 6 receives power from a power supply. The primary light then may stimulate phosphor(s) 3, and phosphor(s) 3 may convert the primary light to a light with longer wavelength(s) (a secondary light). The primary light from the light emitting diode 6 and the secondary light from the phosphors 3 are diffused and mixed together so that a predetermined color of light in visible spectrum may be emitted from light emitting diode 6. In one embodiment, more than one light emitting diodes that have different emission peaks can be mounted together. In some embodiments, a mixture ratio of different phosphors can be adjusted to achieve a desired color of light, color temperature, and CRI.
As described above, if the light emitting diode 6 and the compound(s) included in phosphor 3 are properly controlled then the desired color temperature or specific color coordination can be provided, especially, wide range of color temperature, for example, from about 2,000K to about 8,000K or about 10,000K and/or color rendering index of greater than about 60. In some embodiments, the compound(s) included in the phosphor 3 can be controlled to have a color rendering index between about 50 and about 90. In some embodiments, the compound(s) included in the phosphor 3 can be controlled to have a color rendering index greater than about 90. In some embodiments, the compound(s) included in the phosphor 3 can be controlled to have a color rendering index between about 90 and about 95. Therefore, the light emitting devices exemplarily described herein may be used for electronic devices such as home appliances, stereos, telecommunication devices, and for interior/exterior custom displays. The light emitting devices exemplarily described herein may also be used for automobiles and illumination products because they provide similar color temperatures and CRI to those of the visible light.
In top-type package light emitting device 50, more than one light emitting diodes can be mounted. Each of such light emitting diodes may have a different peak wavelength from that of others. Phosphor 3 may comprise a plurality of single compounds with different emission peaks. The proportion of each of such plurality of compounds may be regulated. Such a phosphor may be applied to the light emitting diode and/or uniformly distributed in the hardening material of the reflector 31. As explained more fully below, the phosphor may include lead- and/or copper containing aluminate type compounds, lead- and/or copper containing silicates, lead- and/or copper containing antimonates, lead- and/or copper containing germanates, lead- and/or copper containing germanate-silicates, lead and/or copper containing phosphates, or any combination thereof.
In one embodiment, the light emitting device of the
Regular volume of phosphor 3, which may be mixed in the epoxy resin, may be provided in diode holder 53. As explained more fully below, phosphor 3 may include lead- and/or copper containing components.
Moreover, the diode holder may include the light emitting diode 6 and the phosphor 3 may be sealed with hardening material such as epoxy resin or silicon resin. The sealing material may cover the light emitting diode 6 and the phosphor 3.
In one embodiment, the lamp type package light emitting device may have more than one pair of electrode pair leads. The light emitting device may include a plurality of leads, and a diode holder 53 may be arranged at the end of one of the plurality of leads. An electrically conductive device may connect the light emitting diode 6 with another of the plurality of leads, and the light emitting diode 6 may be arranged in the diode holder 53 and comprise a plurality of electrodes.
One or more light emitting diodes may be mounted directly on one lead frame 74, and an electrode of the light emitting diode 6 and another lead frame 74 may be connected via electrically conductive wire. In another embodiment, one or more light emitting diodes may be mounted directly on the heat sink 71, as opposed to directly on the lead frame 74, via thermally conductive adhesive. Electrically conductive pate 9 may be provided between light emitting diode 6 and lead frame 74. The phosphor 3 may be placed on top and side faces of light emitting diode 6.
Light emitting device for high power 80 may have housing 63, which may contain light emitting diodes 6, 7, phosphor 3 arranged on the top and side faces of light emitting diodes 6, 7, one or more heat sinks 61, 62, and one or more lead frames 64. In one embodiment, one or more light emitting diodes 6, 7 may be mounted directly on one or more of the heat sinks 61, 62 via thermally conductive adhesive. In one or more of the lead frames 64. The lead frames 64 may receive power from a power supplier and may protrude from housing 63. The light emitting device 80 may include a housing 63, a heat sink 61 or 62 at least partially provided in the housing 63, a plurality of lead frames 64 arranged on or around the heat sink 61 or 62, and an electrically conductive device to connect the light emitting diode 6 or 7 with one of the plurality of lead frames 64. The light emitting diode 6 or 7 may be arranged on the heat sink 61 or 62.
In the light emitting devices for high power 70, 80 in the
In a light emitting device for high power, one or more light emitting diodes can be used selectively and the phosphor can be regulated depending on the light emitting diode. As explained more fully below, the phosphor may include lead and/or copper containing components.
A light emitting device for high power may have a radiator (not shown) and/or heat sink(s). Air or a fan may be used to cool the radiator.
The light emitting devices exemplarily described herein are not limited to the structures described above, and the structures can be modified depending on the characteristics of light emitting diodes, phosphor, wavelength of light, and also applications. Moreover, new part can be added to the structures.
Exemplary embodiments of the phosphor 3 are described as follows.
(Phosphor)
According to some embodiments, the phosphor 3 may include one or more lead- and/or copper containing chemical compounds. The phosphor 3 may be excited by UV and/or visible (e.g., blue) light, and emit light due to transitions of the direct type, f-d transitions, or charge transfer transitions. In some embodiments, the lead- and/or copper-containing chemical compounds may be generally characterized as including a host lattice having anions and cations. In some embodiments, at least a portion of the cations are divalent cations. In some embodiments, the divalent cations include alkaline earth ions. In some embodiments, at least a portion of the divalent cations of the host lattice are substituted by divalent lead and/or divalent copper ions.
The phosphor 3 may include a first compound including a host material including divalent copper ions and oxygen, and a second compound including a different composition than the first compound. The first compound may include an aluminate containing copper, an antimonate containing copper, a germanate containing copper, a germanate-silicate containing copper, a phosphate containing copper, or any combination thereof.
As mentioned above, conventional luminescent materials and phosphors are generally unstable in water, air humidity, water steam and polar solvents. However, due to a higher covalency and a lower basicity, the substitutionally-incorporated divalent lead and/or divalent copper ions in the host lattice of the chemical compound yields luminescent materials have improved resistance against water, air humidity and polar solvents. Moreover, it will be appreciated that the divalent lead and/or divalent copper ions within the host lattice do not act as activators (also referred to herein as “luminescent center ions”) and, therefore do not luminesce.
As described above, the phosphor 3 may include one or more chemical compounds such as, for example, aluminates, silicates, antimonates, germanates, germanate-silicates, and/or phosphates. Exemplary embodiments of these chemical compounds are described in greater detail below.
In some embodiments, the lead- and/or copper-containing aluminates may be generally characterized according to formulas (1), (2), and (5)
a(M′O).b(M″2O).c(M″X).d(Al2O3).e(M′″O).f(M″″2O3).g(M′″″oOp).h(M″″″xOy) (1)
wherein M′ may be Pb, Cu, and/or any combination thereof; M″ may be one or more monovalent elements, for example, Li, Na, K, Rb, Cs, Au, Ag, and/or any combination thereof; M′″ may be one or more divalent elements, for example, Be, Mg, Ca, Sr, Ba, Zn, Cd, Mn, and/or any combination thereof; M″″ may be one or more trivalent elements, for example, Sc, B, Ga, In, and/or any combination thereof; M′″″ may be Si, Ge, Ti, Zr, Mn, V, Nb, Ta, W, Mo, and/or any combination thereof; M″″″ may be Bi, Sn, Sb, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and/or any combination thereof, X may be F, Cl, Br, I, and/or any combination thereof; 0<a≦2; 0≦b≦2; 0≦c≦2; 0<d≦8; 0<e≦4; 0≦f≦3; 0≦g≦8; 0<h≦2; 1≦o≦2; 1≦p≦5; 1≦x≦2; and 1≦y≦5.
a(M′O)b(M″2O)c(M″X)4-a-b
−c(M′″O)7(Al2O3)d(B2O3)e(Ga2O3)f(SiO2)g(GeO2)h(M″″xOy) (2)
wherein M′ may be Pb, Cu, and/or any combination thereof; M″ may be one or more monovalent elements, for example, Li, Na, K, Rb, Cs, Au, Ag, and/or any combination thereof; M′″ may be one or more divalent elements, for example, Be, Mg, Ca, Sr, Ba, Zn, Cd, Mn, and/or any combination thereof; M″″ may be Bi, Sn, Sb, Sc, Y, La, In Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and any combination thereof, X may be F, Cl, Br, I, and any combination thereof; 0<a≦4; 0≦b≦2; 0≦c≦2; 0≦d≦1; 0≦e≦1; 0≦f≦1; 0≦g≦1; 0<h≦2; 1≦x≦2; and 1≦y≦5.
The preparation of copper—as well as lead containing luminescent materials may be a basic solid state reaction. Pure starting materials without any impurities, e.g. iron, may be used.
Any starting material which may transfer into oxides via a heating process may be used to form oxygen dominated phosphors.
Preparation of the luminescent material having formula (3)
Cu0.02Sr3.98Al14O25:Eu (3)
Starting materials: CuO, SrCO3, Al(OH)3, Eu2O3, and/or any combination thereof.
The starting materials in the form of oxides, hydroxides, and/or carbonates may be mixed in stoichiometric proportions together with small amounts of flux, e.g., H3BO3. The mixture may be fired in an alumina crucible in a first step at about 1,200° C. for about one hour. After milling the pre-fired materials a second firing step at about 1,450° C. in a reduced atmosphere for about 4 hours may be followed. After that the material may be milled, washed, dried and sieved. The resulting luminescent material may have an emission maximum of about 494 nm.
Preparation of the luminescent material having formula (4)
Pb0.05Sr3.95Al14O25:Eu (4)
Starting materials: PbO, SrCO3, Al2O3, Eu2O3, and/or any combination thereof.
The starting materials in form of very pure oxides, carbonates, or other components which may decompose thermally into oxides, may be mixed in stoichiometric proportion together with small amounts of flux, for example, H3BO3. The mixture may be fired in an alumina crucible at about 1,200° C. for about one hour in the air. After milling the pre-fired materials a second firing step at about 1,450° C. in air for about 2 hours and in a reduced atmosphere for about 2 hours may be followed. Then the material may be milled, washed, dried, and sieved. The resulting luminescent material may have an emission maximum of from about 494.5 nm.
a(M′O).b(M″O).c(Al2O3).d(M′″O2).e(M″″O2).f(M′″″xOy) (5)
wherein M′ may be Pb, Cu, and/or any combination thereof; M″ may be Be, Mg, Ca, Sr, Ba, Zn, Cd, Mn, and/or any combination thereof; M′″ may be B, Ga, In, and/or any combination thereof; M″″ may be Si, Ge, Ti, Zr, Hf, and/or any combination thereof; M′″″ may be Bi, Sn, Sb, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and/or any combination thereof; 0<a≦; 0≦b≦2; 0<c≦8; 0≦d≦1; 0≦e≦1; 0<f≦2; 1≦x≦2; and 1≦y≦5.
Preparation of the luminescent material having formula (6)
Cu0.05Sr0.95Al1.9997Si0.0003O4:Eu (6)
Starting materials: CuO, SrCO3, Al2O3, SiO2, Eu2O3, and/or any combination thereof.
The starting materials in the form of, for example, pure oxides and/or as carbonates may be mixed in stoichiometric proportions together with small amounts of flux, for example, AlF3. The mixture may be fired in an alumina crucible at about 1,250° C. in a reduced atmosphere for about 3 hours. After that the material may be milled, washed, dried and sieved. The resulting luminescent material may have an emission maximum of about 521.5 nm.
Preparation of the luminescent material having formula (7)
Cu0.12BaMg1.88Al16O27:Eu (7)
Starting materials: CuO, MgO, BaCO3, Al(OH)3, Eu2O3, and/or any combination thereof.
The starting materials in the form of, for example, pure oxides, hydroxides, and/or carbonates may be mixed in stoichiometric proportions together with small amounts of flux, for example, AlF3. The mixture may be fired in an alumina crucible at about 1,420° C. in a reduced atmosphere for about 2 hours. After that the material may be milled, washed, dried, and sieved. The resulting luminescent material may have an emission maximum of about 452 nm.
Preparation of the luminescent material having formula (8)
Pb0.1Sr0.9Al2O4:Eu (8)
Starting materials: PbO, SrCO3, Al(OH)3, Eu2O3, and/or any combination thereof.
The starting materials in form of, for example, pure oxides, hydroxides, and/or carbonates may be mixed in stoichiometric proportions together with small amounts of flux, for example, H3BO3. The mixture may be fired in an alumina crucible at about 1,000° C. for about 2 hours in the air. After milling the pre-fired materials a second firing step at about 1,420° C. in the air for about 1 hour and in a reduced atmosphere for about 2 hours may be followed. After that the material may be milled, washed, dried and sieved. The resulting luminescent material may have an emission maximum of about 521 nm.
Results obtained in regard to copper- and/or lead doped aluminates are shown in table 7.
In some embodiments, the lead- and/or copper-containing silicates may be generally characterized according to formula (9)
a(M′O).b(M″O).c(M″X).d(M′″2O).e(M″″2O3).f(M′″″oOp).g(SiO2).h(M″″″xOy) (9)
wherein M′ may be Pb, Cu, and/or any combination thereof; M″ may be Be, Mg, Ca, Sr, Ba, Zn, Cd, Mn, and/or any combination thereof; M′″ may be Li, Na, K, Rb, Cs, Au, Ag, and/or any combination thereof; M″″ may be Al, Ga, In, and/or any combination thereof; M′″″ may be Ge, V, Nb, Ta, W, Mo, Ti, Zr, Hf, and/or any combination thereof; M may be Bi, Sn, Sb, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and/or any combination thereof; X may be F, Cl, Br, I, and any combination thereof; 0<a≦2; 0<b≦8; 0≦c≦4; 0≦d≦2; 0≦e≦2; 0≦f≦2; 0<g≦10; 0<h≦5; 1≦o≦2; 1≦p≦5; 1≦x≦2; and 1≦y≦5.
The copper-containing silicates exemplarily described herein may, in some embodiments, contain SiO4 and can be characterized as having an Olivin structure (orthorhombic) or β-K2SO4 structure (orthorhombic); contain Si2O8 and be characterized as having a trigonal Glaserite (K3Na(SO4)2) or monoclinic Merwinite structure; contain Si2O7 and be characterized as having a tetragonal Ackermanite structure; contain SiO5 and be characterized as having a tetragonal structure; and/or contain Si2O5 and be characterized as having an orthorhombic structure.
Preparation of the luminescent material having formula (10)
Cu0.05Sr1.7Ca0.25SiO4:Eu (10)
Starting materials: CuO, SrCO3, CaCO3, SiO2, Eu2O3, and/or any combination thereof.
The starting materials in the form of pure oxides and/or carbonates may be mixed in stoichiometric proportions together with small amounts of flux, for example NH4Cl. The mixture may be fired in an alumina crucible at about 1,200° C. in an inert gas atmosphere (e.g., N2 or noble gas) for about 2 hours. Then the material may be milled. After that, the material may be fired in an alumina crucible at about 1,200° C. in a slightly reduced atmosphere for about 2 hours. Then, the material may be milled, washed, dried, and sieved. The resulting luminescent material may have an emission maximum at about 592 nm.
Preparation of the luminescent material having formula (11):
Cu0.2Ba2Zn0.2Mg0.6Si2O7:Eu (11)
Starting materials: CuO, BaCO3, ZnO, MgO, SiO2, Eu2O3, and/or any combination thereof.
The starting materials in the form of very pure oxides and carbonates may be mixed in stoichiometric proportions together with small amounts of flux, for example, NH4Cl. In a first step the mixture may be fired in an alumina crucible at about 1,100° C. in a reduced atmosphere for about 2 hours. Then the material may be milled. After that the material may be fired in an alumina crucible at about 1,235° C. in a reduced atmosphere for about 2 hours. Then that the material may be milled, washed, dried and sieved. The resulting luminescent material may have an emission maximum at about 467 nm.
Preparation of the luminescent material having formula (12)
Pb0.1Ba0.95Sr0.95Si0.998Ge0.002O4:Eu (12)
Starting materials: PbO, SrCO3, BaCO3, SiO2, GeO2, Eu2O3, and/or any combination thereof.
The starting materials in the form of oxides and/or carbonates may be mixed in stoichiometric proportions together with small amounts of flux, for example, NH4Cl. The mixture may be fired in an alumina crucible at about 1,000° C. for about 2 hours in the air. After milling the pre-fired materials a second firing step at 1,220° C. in air for 4 hours and in reducing atmosphere for 2 hours may be followed. After that the material may be milled, washed, dried and sieved. The resulting luminescent material may have an emission maximum at about 527 nm.
Preparation of the luminescent material having formula (13)
Pb0.25Sr3.75Si3O8Cl4:Eu (13)
Starting materials: PbO, SrCO3, SrCl2SiO2, Eu2O3, and any combination thereof.
The starting materials in the form of oxides, chlorides, and/or carbonates may be mixed in stoichiometric proportions together with small amounts of flux, for example, NH4Cl. The mixture may be fired in an alumina crucible in a first step at about 1,100° C. for about 2 hours in the air. After milling the pre-fired materials a second firing step at about 1,220° C. in the air for about 4 hours and in a reduced atmosphere for about 1 hour may be followed. After that the material may be milled, washed, dried and sieved. The resulting luminescent material may have an emission maximum at about 492 nm.
Results obtained with respect to copper- and/or lead-containing silicates are shown in table 12.
In some embodiments, the lead- and/or copper-containing antimonates may be generally characterized according to formula (14)
a(M′O).b(M″2O).c(M″X).d(Sb2O5).e(M′″O).f(M″″xOy) (14)
wherein M′ may be Pb, Cu, and/or any combination thereof; M″ may be Li, Na, K, Rb, Cs, Au, Ag, and/or any combination thereof; M′″ may be Be, Mg, Ca, Sr, Ba, Zn, Cd, Mn, and/or any combination thereof; M″″ may be Bi, Sn, Sc, Y, La, Pr, Sm, Eu, Tb, Dy, Gd, and/or any combination thereof; X may be F, Cl, Br, I, and/or any combination thereof; 0<a≦2; 0≦b≦2; 0≦c≦4; 0<d≦8; 0≦e≦8; 0≦f≦2; 1≦x≦2; and 1≦y≦5.
Preparation of the luminescent material having formula (15)
Cu0.2Mg1.7Li0.2Sb2O7:Mn (15)
Starting materials: CuO, MgO, Li2O, Sb2O5, MnCO3, and/or any combination thereof.
The starting materials in the form of oxides may be mixed in stoichiometric proportion together with small amounts of flux. In a first step the mixture may be fired in an alumina crucible at about 985° C. in the air for about 2 hours. After pre-firing the material may be milled again. In a second step the mixture may be fired in an alumina crucible at about 1,200° C. in an atmosphere containing oxygen for about 8 hours. After that the material may be milled, washed, dried and sieved. The resulting luminescent material may have an emission maximum at about 626 nm.
Preparation of the luminescent material having formula (16)
Pb0.006Ca0.6Sr0.394Sb2O6 (16)
Starting materials: PbO, CaCO3, SrCO3, Sb2O5, and/or any combination thereof.
The starting materials in the form of oxides and/or carbonates may be mixed in stoichiometric proportions together with small amounts of flux. In a first step the mixture may be fired in an alumina crucible at about 975° C. in the air for about 2 hours. After pre-firing the material may be milled again. In a second step the mixture may be fired in an alumina crucible at about 1,175° C. in the air for about 4 hours and then in an oxygen-containing atmosphere for about 4 hours. After that the material may be milled, washed, dried and sieved. The resulting luminescent material may have an emission maximum at about 637 nm.
Results obtained in respect to copper- and/or lead-containing antimonates are shown in table 15.
In some embodiments, the lead- and/or copper-containing germanates and/or germanate-silicates may be generally characterized according to formula (17)
a(M′O).b(M″2O)c(M″X).d(GeO2).e(M′″O).f(M″″2O3).g(M′″″oOp).h(M″″″xOy) (17)
wherein M′ may be Pb, Cu, and/or any combination thereof; M″ may be Li, Na, K, Rb, Cs, Au, Ag, and/or any combination thereof; M′″ may be Be, Mg, Ca, Sr, Ba, Zn, Cd, and/or any combination thereof; M″″ may be Sc, Y, B, Al, La, Ga, In, and/or any combination thereof; M′″″ may be Si, Ti, Zr, Mn, V, Nb, Ta, W, Mo, and/or any combination thereof; M″″″ may be Bi, Sn, Pr, Sm, Eu, Gd, Dy, and/or any combination thereof X may be F, Cl, Br, I, and/or any combination thereof 0<a≦2; 0≦b≦2; 0≦c≦10; 0<d≦10; 0≦e≦14; 0≦f≦14; 0≦g≦10; 0≦h≦2; 1≦o≦2; 1≦p≦5; 1≦x≦2; and 1≦y≦5.
Preparation of the luminescent material having formula (18)
Pb0.004Ca1.99Zn0.006Ge0.8Si0.2O4:Mn (18)
Starting materials: PbO, CaCO3, ZnO, GeO2, SiO2, MnCO3, and/or any combination thereof,
The starting materials in the form of oxides and/or carbonates may be mixed in stoichiometric proportions together with small amounts of flux, for example, NH4Cl. In a first step the mixture may be fired in an alumina crucible at about 1,200° C. in an oxygen-containing atmosphere for about 2 hours. Then, the material may be milled again. In a second step the mixture may be fired in an alumina crucible at about 1,200° C. in oxygen containing atmosphere for about 2 hours. After that the material may be milled, washed, dried and sieved. The resulting luminescent material may have an emission maximum at about 655 nm.
Preparation of the luminescent material having formula (19)
Cu0.46Sr0.54Ge0.6Si0.4O3:Mn (19)
Starting materials: CuO, SrCO3, GeO2, SiO2, MnCO3, and/or any combination thereof.
The starting materials in the form of oxides and/or carbonates may be mixed in stoichiometric proportions together with small amounts of flux, for example, NH4Cl. In a first step the mixture may be fired in an alumina crucible at about 1,100° C. in an oxygen-containing atmosphere for about 2 hours. Then, the material may be milled again. In a second step the mixture may be fired in an alumina crucible at about 1,180° C. in an oxygen-containing atmosphere for about 4 hours. After that the material may be milled, washed, dried and sieved. The resulting luminescent material may have an emission maximum at about 658 nm.
In some embodiments, the lead- and/or copper-containing phosphates may be generally characterized according to formula (20)
a(M′O).b(M″2O).c(M″X).d(P2O5).e(M′″O).f(M″″2O3).g(M′″″O2).h(M″″″xOy) (20)
wherein M′ may be Pb, Cu, and/or any combination thereof; M″ may be Li, Na, K, Rb, Cs, Au, Ag, and/or any combination thereof; M′″ may be Be, Mg, Ca, Sr, Ba, Zn, Cd, Mn, and/or any combination thereof; M″″ may be Sc, Y, B, Al, La, Ga, In, and/or any combination thereof; M′″″ may be Si, Ge, Ti, Zr, Hf, V, Nb, Ta, W, Mo, and/or any combination thereof; M″″″ may be Bi, Sn, Pr, Sm, Eu, Gd, Dy, Ce, Th, and/or any combination thereof, X may be F, Cl, Br, I, and/or any combination thereof; 0<a≦2; 0≦b≦12; 0≦c≦16; 0<d≦3; 0≦e≦5; 0≦f≦3; 0≦g≦2; 0<h≦2; 1≦x≦2; and 1≦y≦5.
Preparation of the luminescent material having formula (21)
Cu0.02Ca4.98(PO4)3Cl:Eu (21)
Starting materials: CuO, CaCO3, Ca3(PO4)2, CaCl2, Eu2O3, and/or any combination thereof,
The starting materials in the form of oxides, phosphates, and/or carbonates and chlorides may be mixed in stoichiometric proportions together with small amounts of flux. The mixture may be fired in an alumina crucible at about 1,240° C. in reducing atmosphere for about 2 hours. After that the material may be milled, washed, dried and sieved. The luminescent material may have an emission maximum at about 450 nm.
Meanwhile, the phosphor of the light emitting device can comprise aluminate, silicate, antimonate, germanate, phosphate type chemical compound, and any combination thereof.
In such an embodiment, part of the initial about 405 nm wavelength emission light from the light emitting diode is absorbed by the phosphor, and it is converted to longer 2nd wavelength. The 1st and 2nd light is mixed together and the desire emission is produced. As the shown
The phosphor is composed of Cu0.05Sr1.7Ca0.25SiO4:Eu which may have peak wavelength at about 592 nm, Pb0.1Ba0.95Sr0.95Si0.998Ge0.002O4:Eu which may have peak wavelength at about 527 nm, and Cu0.05Li0.002Sr1.5Ba0.448SiO4:Gd, Eu which may have peak wavelength at about 557 nm.
In such an embodiment, part of the initial about 455 nm wavelength emission light from the light emitting diode is absorbed by the phosphor, and it is converted to longer 2nd wavelength. The 1st and 2nd light is mixed together and the desire emission is produced. As the shown
The phosphor of the light emitting device exemplarily described herein can be applied by single chemical compound or mixture of plurality of single chemical compound besides the embodiments in relation to
According to the description above, light emitting device with wide range of color temperature about 2,000K to about 8,000K or about 10,000K and superior color rendering index of greater than about 60 (e.g., between about 60 and about 90, or greater than about 90, or between about 90 and about 95) can be realized by using the lead- and/or copper-containing chemical compounds.
In such a wavelength conversion, the light emitting device exemplarily described herein is capable of use in mobile phones, note book computers and electronic devices such as home appliance, stereo, telecommunication products, as well as in custom display's key pad and back light applications. Moreover, the light emitting device exemplarily described herein can be applied in automobiles, medical instruments and illumination products.
In addition, the chemical compounds exemplarily described herein can be incorporated within paint as a pigment capable of converting wavelengths of light.
According to the embodiments exemplarily described above, the chemical can increase the stability of the light emitting device against water, humidity, vapor as well as other polar solvents.
In the foregoing described embodiments, various features are grouped together in a single embodiment for purposes of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate preferred embodiment of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2004-042396 | Jun 2004 | KR | national |
This application is a continuation of U.S. patent application Ser. No. 12/491,457, filed on Jun. 25, 2009, which is a continuation-in-part of U.S. patent application Ser. No. 11/948,845, filed on Nov. 30, 2007 (issued as U.S. Pat. No. 8,066,909), which is a continuation-in-part of U.S. patent application Ser. No. 11/024,702, filed on Dec. 30, 2004 (issued as U.S. Pat. No. 7,554,129), the disclosures of which are incorporated by reference herein in their entirety, which claim priority of Korean Patent Application No. 10-2004-042396, filed Jun. 10, 2004, the disclosure of which is incorporated by reference herein in its entirety.
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