LIGHT EMITTING DEVICE

Abstract

A light emitting device is disclosed. The light emitting device may include a light emitting diode (LED) for emitting light and a phosphor adjacent to the LED. The phosphor may be excitable by light emitted by the LED and may include a first compound having a host lattice comprising first ions and oxygen. In one embodiment, the host lattice may include silicon, the copper ions may be divalent copper ions and the first compound may have 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 or an orthorhombic crystal structure. In another embodiment, the copper ions do not act as luminescent ions upon excitation with the light emitted by the LED.

Description

BACKGROUND

1. Field of 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.

SUMMARY

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.

BRIEF DESCRIPTION OF THE DRAWINGS

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:

FIG. 1 shows a side cross-sectional view of an illustrative embodiment of a portion of a chip-type package light emitting device;

FIG. 2 shows a side cross-sectional view of an illustrative embodiment of a portion of a top-type package light emitting device;

FIG. 3 shows a side cross-sectional view of an illustrative embodiment of a portion of a lamp-type package light emitting device;

FIG. 4 shows a side cross-sectional view of an illustrative embodiment of a portion of a light emitting device for high power;

FIG. 5 shows a side cross-sectional view of another illustrative embodiment of a portion of a light emitting device for high power;

FIG. 6 shows emitting spectrum of a light emitting device with luminescent material; and

FIG. 7 shows emitting spectrum of the light emitting device with luminescent material according to another embodiment.

DETAILED DESCRIPTION

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)

FIG. 1 shows a side cross-sectional view of an illustrative embodiment of a portion of a chip-type package light emitting device. The chip-type package light emitting device may comprise at least one light emitting diode and a phosphorescent substance. Electrodes 5 may be formed on both sides of substrate 1. Light emitting diode 6 emitting light may be mounted on one of the electrodes 5. Light emitting diode 6 may be mounted on electrode 5 through electrically conductive paste 9. An electrode of light emitting diode 6 may be connected to electrode pattern 5 via an electrically conductive wire 2.

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 use.

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 diff-used 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 60 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.

FIG. 2 shows a side cross-sectional view of an illustrative embodiment of a portion of a top-type package light emitting device. A top-type package light emitting device may have a similar structure as that of the chip type package light emitting device 40 of FIG. 1. The top-type package device may have reflector 31 which may reflect the light from the light emitting diode 6 to the desire direction.

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 FIG. 1 or FIG. 2 can include a metal substrate, which may have good heat conductivity. Such a light emitting device may easily dissipate the heat from the light emitting diode. Therefore, light emitting devices for high power may be manufactured. If a heat sink is provided beneath the metal substrate, the heat from the light emitting diode may be dissipated more effectively.

FIG. 3 shows a side cross-sectional view of an illustrative embodiment of a portion of a lamp-type package light emitting device. Lamp type light emitting device 60 may have a pair of leads 51, 52, and a diode holder 53 may be formed at the end of one lead. Diode holder 53 may have a shape of cup, and one or more light emitting diodes 6 may provided in the diode holder 53. When a number of light emitting diodes are provided in the diode holder 53, each of them may have a different peak wavelength from that of others. An electrode of light emitting diode 6 may be connected to lead 52 by, for example, electrically conductive wire 2.

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.

In one embodiment, the lamp type package light emitting device may have more than one pair of electrode pair leads.

FIG. 4 shows a side cross-sectional view of an illustrative embodiment of a portion of a light emitting device for high power. Heat sink 71 may be provided inside of housing 73 of the light emitting device for high power 70, and it may be partially exposed to outside. A pair of lead frames 74 may protrude from housing 73.

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.

FIG. 5 shows a side cross-sectional view of another illustrative embodiment of a portion of a light emitting device for high power.

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 embodiment, one or more light emitting diodes 6, 7 may be mounted directly on 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.

In the light emitting devices for high power 70, 80 in the FIGS. 4 and 5, the phosphor 3 can be added to the paste, which may be provided between heat sink and light emitting devices. A lens may be combined with housing 63, 73.

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. 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.

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′″″_oO_p).h(M″″″_xO_y)   (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″″_xO_y)   (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.

EXAMPLES OF PREPARATION

Preparation of the luminescent material having formula (3) Cu_0.02Sr_3.98Al₁₄O₂₅: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.

TABLE 1
copper-containing Eu2+-activated aluminate compared with Eu2+-activated
aluminate without copper at about 400 nm excitation wavelength
	Copper-containing
	compound	Compound without
	Cu0.02Sr3.98Al14O25:	copper
	Eu	Sr4Al14O25: Eu
Luminous density (%)	103.1	100
Wavelength (nm)	494	493

Preparation of the luminescent material having formula (4) Pb_0.05 Sr_3.95Al₁₄O₂₅: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.

TABLE 2
lead-containing Eu2+-activated aluminate compared with Eu2+-activated
aluminate without lead at about 400 nm excitation wavelength
	Lead-containing
	compound	Compound without
	Pb0.05Sr3.95Al14O25:	lead
	Eu	Sr4Al14O25: Eu
Luminous density (%)	101.4	100
Wavelength (nm)	494.5	493

TABLE 3
optical properties of some copper- and/or lead-containing aluminates excitable by long wave ultraviolet
and/or by visible light and their luminous density in % at 400 nm excitation wavelength
		Luminous density at
		400 nm excitation
		compared with	Peak wavelength of
	Possible	compounds not	lead-/copper-	Peak wavelength of
	excitation	containing	containing	materials without
Composition	range(nm)	copper/lead (%)	materials (nm)	lead/copper (nm)
Cu0.5Sr3.5Al14O25: Eu	360-430	101.2	495	493
Cu0.02Sr3.98Al14O25: Eu	360-430	103.1	494	493
Pb0.05Sr3.95Al14O25: Eu	360-430	101.4	494.5	493
CU0.01Sr3.99Al13.995Si0.005O25:	360-430	103	494	492
Eu
Cu0.01Sr3.395Ba0.595Al14O25:	360-430	100.8	494	493
Eu, Dy
Pb0.05Sr3.95Al13.95Ga0.05O25: Eu	360-430	101.5	494	494

a(M′O).b(M″O).c(Al₂O₃).d(M′″₂O₃).e(M″″O₂).f(M′″″_xO_y)   (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≦1; 0≦b≦2; 0<c≦8; 0≦d≦1; 0≦e≦1; 0<f≦2; 1≦x≦2; and 1≦y≦5.

EXAMPLE OF PREPARATION

Preparation of the luminescent material having formula (6) Cu_0.05Sr_0.95Al_1.9997Si_0.0003O₄: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.

TABLE 4
copper-containing Eu2+-activated aluminate compared with Eu2+-activated
aluminate without copper at about 400 nm excitation wavelength
	Copper-containing
	compound	Compound without
	Cu0.05Sr0.95Al1.9997Si0.0003O4:	copper
	Eu	SrAl2O4: Eu
Luminous	106	100
density (%)
Wavelength (nm)	521.5	519

Preparation of the luminescent material having formula (7) Cu0.12BaMg_1.88Al₁₆O₂₇: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.

TABLE 5
copper-containing Eu2+-activated aluminate compared with copper not
doped Eu2+-activated aluminate at 400 nm excitation wavelength
	Copper-containing
	compound	Comparison without
	Cu0.12BaMg1.88Al16O27:	copper
	Eu	BaMg2Al16O27: Eu
Luminous density (%)	101	100
Wavelength (nm)	452	450

Preparation of the luminescent material having formula (8) Pb_0.1Sr_0.9Al₂O₄: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.

TABLE 6
lead-containing Eu2+-activated aluminate compared with Eu2+-activated
aluminate without lead at about 400 nm excitation wavelength
	Lead-containing
	compound	Compound without
	Pb0.1Sr0.9Al2O4:	lead
	Eu	SrAl2O4: Eu
Luminous density (%)	102	100
Wavelength (nm)	521	519

Results obtained in regard to copper- and/or lead-containing aluminates are shown in table 7.

TABLE 7
optical properties of some copper- and/or lead-containing aluminates excitable by long wave ultraviolet
and/or by visible light and their luminous density in % at 400 nm excitation wavelength
		Luminous density at
		400 nm excitation
		compared with	Peak wavelength of
	Possible	compounds not	lead-/copper-	Peak wavelength of
	excitation	containing	containing	materials without
Composition	range (nm)	copper/lead (%)	materials (nm)	lead/copper (nm)
Cu0.05Sr0.95Al1.9997Si0.0003O4: Eu	360-440	106	521.5	519
Cu0.2Mg0.7995Li0.0005Al1.9Ga0.1O4:	360-440	101.2	482	480
Eu, Dy
Pb0.1Sr0.9Al2O4: Eu	360-440	102	521	519
Cu0.05BaMg1.95Al16O27: Eu, Mn	360-400	100.5	451, 515	450, 515
Cu0.12BaMg1.88Al16O27: Eu	360-400	101	452	450
Cu0.01BaMg0.99Al10O17: Eu	360-400	102.5	451	449
Pb0.1BaMg0.9Al9.5Ga0.5O17: Eu,	360-400	100.8	448	450
Dy
Pb0.08Sr0.902Al2O4: Eu, Dy	360-440	102.4	521	519
Pb0.2Sr0.8Al2O4: Mn	360-440	100.8	658	655
Cu0.06Sr0.94Al2O4: Eu	360-440	102.3	521	519
Cu0.05Ba0.94Pb0.06Mg0.95Al10O17:	360-440	100.4	451	449
Eu
Pb0.3Ba0.7Cu0.1Mg1.9Al16O27:	360-400	100.8	452	450
Eu
Pb0.3Ba0.7Cu1.9Mg1.9Al16O27:	360-400	100.4	452, 515	450, 515
Eu, Mn

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′″″_oO_p).g(SiO₂).h(M′″″_xO_y)   (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′″″ maybe 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 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.

EXAMPLE OF PREPARATION

Preparation of the luminescent material having formula (10) Cu_0.05Sr_1.7Ca_0.25SiO₄: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.

TABLE 8
copper-containing Eu2+-activated silicate compared with Eu2+-activated
silicate without copper at about 400 nm excitation wavelength
	Copper-containing
	compound	Compound without
	Cu0.05Sr1.7Ca0.25SiO4:	copper
	Eu	Sr1.7Ca0.3SiO4: Eu
Luminous density (%)	104	100
Wavelength (nm)	592	588

Preparation of the luminescent material having formula (11): Cu_0.2Ba₂Zn_0.2Mg_0.6Si₂O₇: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.

TABLE 9
copper-containing Eu2+-activated silicate compared with Eu2+-activated
silicate without copper at 400 nm excitation wavelength
	Copper-containing
	compound	Compound without
	Cu0.2Sr2Zn0.2Mg0.6Si2O7:	copper
	Eu	Sr2Zn2Mg0.6Si2O7: Eu
Luminous density (%)	101.5	100
Wavelength (nm)	467	465

Preparation of the luminescent material having formula (12) Pb_0.1Ba_0.95Sr_0.95Si_0.998Ge_0.002O₄: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.

TABLE 10
lead-containing Eu2+-activated silicate compared with Eu2+-activated
silicate without lead at about 400 nm excitation wavelength
	Lead-containing
	compound	Compound without
	Pb0.1Ba0.95Sr0.95Si0.998Ge0.002O4:	lead
	Eu	BaSrSiO4: Eu
Luminous	101.3	100
density (%)
Wavelength	527	525
(nm)

Preparation of the luminescent material having formula (13) Pb_0.25Sr_3.75Si₃O₈Cl₄:Eu   (13)

Starting materials: PbO, SrCO₃, SrCl₂, SiO₂, 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.

TABLE 11
lead-containing Eu2+-activated chlorosilicate compared with Eu2+-activated
chlorosilicate without lead at 400 nm excitation wavelength
	Lead-containing
	compound	Compound without
	Pb0.25Sr3.75Si3O8C14:	lead
	Eu	Sr4Si3O8C4: Eu
Luminous density (%)	100.6	100
Wavelength (nm)	492	490

Results obtained with respect to copper- and/or lead-containing silicates are shown in table 12.

TABLE 12
optical properties of some copper- and/or lead-containing rare earth activated
silicates excitable by long wave ultraviolet and/or by visible light and
their luminous density in % at about 400 nm excitation wavelength
		Luminous density at
		400 nm excitation
		compared with	Peak wavelength of
	Possible	compounds not	lead-/copper-	Peak wavelength of
	excitation	containing	containing	materials without
Composition	range (nm)	copper/lead (%)	materials (nm)	lead/copper (nm)
P0.1Ba0.95Sr0.95Si0.998Ge0.002O4:	360-470	101.3	527	525
Eu
Cu0.02(Ba, Sr, Ca, Zn)1.98SiO4:	360-500	108.2	565	560
Eu
Cu0.05Sr1.7Ca0.25SiO4: Eu	360-470	104	592	588
Cu0.05Li0.002Sr1.5Ba0.448SiO4:	360-470	102.5	557	555
Gd, Eu
Cu0.2Sr2Zn0.2Mg0.6Si2O7: Eu	360-450	101.5	467	465
Cu0.02Ba2.8Sr0.2Mg0.98Si2O8:	360-420	100.8	440, 660	438, 660
Eu, Mn
Pb0.025Sr3.75Si3O8Cl4: Eu	360-470	100.6	492	490
C0.2Ba2.2Sr0.75Pb0.05Zn0.8Si2O8:	360-430	100.8	448	445
Eu
Cu0.2Ba3Mg0.8Si1.99Ge0.01O8:	360-430	101	444	440
Eu
Cu0.5Zn0.5Ba2Ge0.2Si1.8O7: Eu	360-420	102.5	435	433
Cu0.8Mg0.2Ba3Si2O8: Eu, Mn	360-430	103	438, 670	435, 670
Pb0.15Ba1.84Zn0.01Si0.99Zr0.01O4:	360-500	101	512	510
Eu
Cu0.2Ba5Ca2.8Si4O16: Eu	360-470	101.8	495	491

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″″_xO_y)   (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.

EXAMPLES OF PREPARATION

Preparation of the luminescent material having formula (15) Cu_0.2Mg_1.7Li_0.2Sb₂O₇: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.

TABLE 13
copper-containing antimonate compared with antimonate
without copper at about 400 nm excitation wavelength
	Copper-containing
	compound	Comparison without
	Cu0.2Mg1.7Li0.2Sb2O7:	copper
	Mn	Mg2Li0.2Sb2O7: Mn
Luminous density (%)	101.8	100
Wavelength (nm)	652	650

Preparation of the luminescent material having formula (16) Pb_0.006Ca_0.6Sr_0.394Sb₂O₆   (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.

TABLE 14
lead-containing antimonate compared with antimonate
without lead at 400 nm excitation wavelength
	Lead-containing	Compound without
	compound	lead
	Pb0.006Ca0.6Sr0.394Sb2O6	Ca0.6Sr0.4Sb2O6
Luminous density (%)	102	100
Wavelength (nm)	637	638

Results obtained in respect to copper- and/or lead-containing antimonates are shown in table 15.

TABLE 15
optical properties of some copper- and/or lead-containing antimonates excitable by long wave ultraviolet
and/or by visible light and their luminous density in % at about 400 nm excitation wavelength
		Luminous density at
		400 nm excitation
		compared with	Peak wavelength of
	Possible	compounds not	lead-/copper-	Peak wavelength of
	excitation	containing	containing	materials without
Composition	range (nm)	copper/lead (%)	materials (nm)	lead/copper (nm)
Pb0.2Mg0.002Ca1.798Sb2O6F2: Mn	360-400	102	645	649
Cu0.15Ca1.845Sr0.0005Sb1.998Si0.002O7:	360-400	101.5	660	658
Mn
Cu0.2Mg1.7Li0.2Sb2O7: Mn	360-400	101.8	652	650
Cu0.2Pb0.01Ca0.79Sb1.98Nb0.02O6: Mn	360-400	98.5	658	658
Cu0.01Ca1.99Sb1.9995V0.0005O7: Mn	360-400	100.5	660	657
Pb0.006Ca0.6Sr0.394Sb2O6	360-400	102	637	638
Cu0.02Ca0.9Sr0.5Ba0.4Mg0.18Sb2O7	360-400	102.5	649	645
Pb0.198Mg0.004Ca1.798Sb2O6F2	360-400	101.8	628	630

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″₂).c(M″X).d(GeO₂).e(M′″O).f(M″″₂O₃).g(M′″″_oO_p).h(M″″″_xO_y)   (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.

EXAMPLE OF PREPARATION

Preparation of the luminescent material having fonrmula (18) Pb_0.004Ca_1.99Zn_0.006Ge_0.8Si_0.2O₄: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.

TABLE 16
lead-containing Mn-activated germanate compared with Mn-activated
germanate without lead at about 400 nm excitation wavelength
	Copper-containing	Comparison without
	compound	copper
	Pb0.004Ca1.99Zn0.006Ge0.8Si0.2O4:	Ca1.99Zn0.01Ge0.8Si0.2O4:
	Mn	Mn
Luminous	101.5	100
density (%)
Wavelength	655	657
(nm)

Preparation of the luminescent material having formula (19) Cu_0.46Sr_0.54Ge_0.6Si_0.4O₃: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.

TABLE 17
copper-containing Mn-activated germanate-silicate
compared with Mn-activated germanate-silicate without
copper at 400 nm excitation wavelength
	Copper-containing
	compound	Compound without
	Cu0.46Sr0.54Ge0.6Si0.4O3:	copper
	Mn	SrGe0.6Si0.4O3: Mn
Luminous density (%)	103	100
Wavelength (nm)	658	655

TABLE 18
optical properties of some copper- and/or lead-containing germanate-silicates excitable by long wave ultraviolet
and/or by visible light and their luminous density in % at about 400 nm excitation wavelength
		Luminous density at
		400 nm excitation
		compared with	Peak wavelength of
	Possible	compounds not	lead-/copper-	Peak wavelength of
	excitation	containing	containing	materials without
Composition	range (nm)	copper/lead (%)	materials (nm)	lead/copper (nm)
Pb0.004Ca1.99Zn0.006Ge0.8Si0.2O4: Mn	360-400	101.5	655	657
Pb0.002Sr0.954Ca1.044Ge0.93Si0.07O4:	360-400	101.5	660	661
Mn
Cu0.46Sr0.54Ge0.6Si0.4O3: Mn	360-400	103	658	655
Cu0.002Sr0.998Ba0.99Ca0.01Si0.98Ge0.02O4:	360-470	102	538	533
Eu
Cu1.45Mg26.55Ge9.4Si0.6O48: Mn	360-400	102	660	657
Cu1.2Mg26.8Ge8.9Si1.1O48: Mn	360-400	103.8	670	656
Cu4Mg20Zn4Ge5Si2.5O38F10: Mn	360-400	101.5	658	655
Pb0.001Ba0.849Zn0.05Sr1.1Ge0.04Si0.96O4:	360-470	101.8	550	545
Eu
Cu0.05Mg4.95GeO6F2: Mn	360-400	100.5	655	653
Cu0.05Mg3.95GeO5.5F: Mn	360-400	100.8	657	653

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″″″_xO_y)   (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.

EXAMPLES OF PREPARATION

Preparation of the luminescent material having formula (21) Cu_0.02Ca_4.98(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.

TABLE 19
copper-containing Eu2+-activated chlorophosphate compared with Eu2+-
activated chlorophosphate without copper at about 400
nm excitation wavelength
	Copper-containing
	compound	Compound without
	Cu0.02Ca4.98(PO4)3Cl:	copper
	Eu	Ca5(PO4)3Cl: Eu
Luminous density (%)	101.5	100
Wavelength (nm)	450	447

TABLE 20
copper- and/or lead-containing phosphates excitable by long wave ultraviolet and/or by
visible light and their luminous density in % at about 400 nm excitation wavelength
		Luminous density at
		400 nm excitation
		compared with	Peak wavelength of
	Possible	compounds not	lead-/copper-	Peak wavelength of
	excitation	containing	containing	materials without
Composition	range (nm)	copper/lead (%)	materials (nm)	lead/copper (nm)
Cu0.02Sr4.98(PO4)3Cl: Eu	360-410	101.5	450	447
Cu0.2Mg0.8BaP2O7: Eu, Mn	360-400	102	638	635
Pb0.5Sr1.5P1.84B0.16O6.84: Eu	360-400	102	425	420
Cu0.5Mg0.5Ba2(P, Si)2O8: Eu	360-400	101	573	570
Cu0.5Sr9.5(P, B)6O24Cl2: Eu	360-410	102	460	456
Cu0.5Ba3Sr6.5P6O24(F, Cl)2:	360-410	102	443	442
Eu
Cu0.05(Ca, Sr, Ba)04.95P3O12Cl:	360-410	101.5	438, 641	435, 640
Eu, Mn
Pb0.1Ba2.9P2O8: Eu	360-400	103	421	419

Meanwhile, the phosphor of the light emitting device can comprise aluminate, silicate, antimonate, germanate, phosphate type chemical compound, and any combination thereof.

FIG. 6 is one of the embodiment's emission spectrum, which the phosphor is used for the light emitting device. The embodiment may have a light emitting diode with 405 nm wavelength and the phosphor, which is mixture of the selected multiple chemical compounds in proper ratio. The phosphor may be composed of Cu_0.05BaMg_1.95Al₁₆O₂₇:Eu which may have peak wavelength at about 451 nm, Cu_0.03Sr_1.5Ca_0.47SiO₄:Eu which may have peak wavelength at 586 nm, Pb_0.006Ca_0.6Sr_0.394Sb₂O₆:Mn⁴⁺ which may have peak wavelength at about 637 nm, Pb_0.15Ba_1.84Zn_0.01Si_0.99Zr_0.01O₄:Eu which may have peak wavelength at around 512 nm, and Cu_0.2Sr_3.8Al₁₄O₂₅:Eu which may have peak wavelength at about 494 nm.

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 2^nd wavelength. The 1^st and 2^nd light is mixed together and the desire emission is produced. As the shown FIG. 6, the light emitting device convert the 1^st UV light of 405 nm wavelength to wide spectral range of visible light, that is, white light, and at this time the color temperature is about 3,000K and CRI is about 90 to about 95.

FIG. 7 is another embodiment's emission spectrum, which the phosphor is applied for the light emitting device. The embodiment may have a light emitting diode with about 455 nm wavelength and the phosphor, which is mixture of the selected multiple chemical compounds in proper ratio.

The phosphor is composed of Cu_0.05Sr_1.7Ca_0.25SiO₄:Eu which may have peak wavelength at about 592 nm, Pb_0.1Ba_0.95Sr_0.95Si_0.998Ge_0.002O₄:Eu which may have peak wavelength at about 527 nm, and Cu_0.05Li_0.002Sr_1.5Ba_0.448SiO₄: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 2^nd wavelength. The 1^st and 2^nd light is mixed together and the desire emission is produced. As the shown FIG. 7, the light emitting device convert the 1^st blue light of about 455 nm wavelength to wide spectral range of visible light, that is, white light, and at this time the color temperature is about 4,000K to about 6,500K and CRI is about 86 to about 93.

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 FIG. 6 and FIG. 7, which are explained above.

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 exemplarily described herein.

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.

Claims

1. A light emitting device, comprising: a light emitting diode (LED) for emitting light; and a phosphor adjacent to the LED, wherein the phosphor is excitable by light emitted by the LED, the phosphor including a first compound having a host lattice comprising first ions, silicon and oxygen, wherein a first portion of the first ions is substituted by divalent copper ions, and the first compound has an Olivin crystal structure, a β-K2SO4 crystal structure, trigonal Glaserite (K3Na(SO4)2) or monoclinic Merwinite crystal structure, a tetragonal Ackermanite crystal structure, a tetragonal crystal structure or an orthorhombic crystal structure.

2. The light emitting device of claim 1, wherein the phosphor has a color temperature ranging from about 2,000K to about 8,000K.

3. The light emitting device of claim 1, wherein the phosphor has a color temperature of about 10,000K.

4. The light emitting device of claim 1, wherein the phosphor has a color rendering index greater than about 60.

5. The light emitting device of claim 4, wherein the phosphor has a color rendering index between about 60 and about 90.

6. The light emitting device of claim 4, wherein the phosphor has a color rendering index greater than about 90.

7. The light emitting device of claim 1, wherein the first ions comprise at least one of Be, Mg, Ca, Sr, Ba, Zn, Cd and Mn.

8. The light emitting device of claim 1, wherein the first compound further comprises at least one of Bi, Sn, Sb, Sc, Y. La, In, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu.

9. The light emitting device of claim 1, wherein the host lattice of the first compound further comprises Ge.

10. The light emitting device of claim 1, wherein the phosphor further comprises at least one second compound selected from the group consisting of an aluminate, another lo silicate, an antimonate, a germanate, a germanate-silicate and a phosphate.

11. A light emitting device, comprising: a light emitting diode (LED) for emitting light; and a phosphor adjacent to the LED, wherein the phosphor is excitable by light emitted by the LED, the phosphor including a first compound having a host lattice comprising first ions and oxygen, wherein a first portion of the first ions is substituted by copper ions, and the copper ions do not act as luminescent ions upon excitation with the light emitted by the LED.