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Description
LIGHT EMITTING DEVICE
Technical Field
The invention relates to light emitting devices and more particularly to light
emitting devices including at least one light-emitting diode and phosphor, the phosphor
including lead and/or copper doped chemical compounds and converting the
wavelength of light.
Background 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, in such a usual white LED, color temperature range is narrow which is
between about 6,000-8,000K, and CRI (Color Rendering Index) is about 60 to 75.
Therefore, it is hard to produce the white LED with color coordination and color
temperature that arc similar to those of the visible light. It is one of the reasons why
only white light color with a cold feeling could be realized. Moreover, 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.
Disclosure of Invention
Technical Problem
Accordingly, the present invention is conceived to solve the aforementioned
problems in the prior art. It is an object of the present invention to provide a light
emitting device capable of providing wide range of color temperature from about
2,000K to about 8,000K or about 10,000K and/or color rendering index of greater than
about 90.
Another object of the present invention is to provide a light emitting device in
which desired color temperature or specific color coordination can be easily embodied.
An additional object of the present invention is to provide a light emitting device
with improved luminescent properties and also with improved stability against water,
humidity as well as other polar solvents.
Technical Solution
Wavelength conversion light emitting device are provided. In one embodiment
consistent with this invention, a device is provided for emitting light The device can
include a substrate, a plurality of electrodes provided on the substrate, a light emitting
diode configured to emit light, the light emitting diode being provided on one of the
plurality of electrodes, phosphors configured to change a wavelength of the light, the
phosphors substantially covering at least a portion of the light emitting diode, and an
electrically conductive device configured to connect the light emitting diode with
another of the plurality of electrodes.
In another embodiment consistent with this invention, a light emitting device can
include a plurality of leads , a diode holder provided at the end of one of the plurality
of lead, a light emitting diode provided in the diode holder, the light emitting diode .
including a plurality of electrodes, phosphors configured to change a wavelength of the
light, me phosphors substantially covering at least a portion of the light emitting diode;
and an electrically conductive device configured to connect the light emitting device
with another of the plurality of leads .
In another embodiment consistent with this invention, a light emitting device may
include a housing, a heat sink at least partially provided in the housing, a plurality of
lead frames provided on the heat sink, a light emitting diode mounted on one of the
plurality of lead frames, phosphors configured to change a wavelength of the light, the
phosphors substantially covering at least a portion of the light emitting diode, and an
electrically conductive device configured to connect the light emitting diode with
another of the plurality of lead frames.
The phosphor in consistent with this invention may include aluminate type
compounds, lead and/or copper doped silicates, lead and/or copper doped antimonates,
lead and/or copper doped germanates, lead and/or copper doped germanate-silicates,
lead and/or copper doped phosphates, or any combination thereof. Formulas for
phosphors consistent with this invention are also provided.
Brief Description Of The Accompanying Drawings
Further aspects 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 consistent with this invention;
Fig. 2 shows a side cross-sectional view of an illustrative embodiment of a portion
of a top-type package light emitting device consistent with this invention;
Fig. 3 shows a side cross-sectional view of an illustrative embodiment of a portion
of a lamp-type package light emitting device consistent with this invention;
Fig. 4 shows a side cross-sectional view of an illustrative embodiment of a portion
of a light emitting device for high power consistent with this invention;
Fig. 5 shows a side cross-sectional view of another illustrative embodiment of a
portion of a light emitting device for high power consistent with this invention;
Fig. 6 shows emitting spectrum of a light emitting device with luminescent
material consistent with this invention; and
Fig. 7 shows emitting spectrum of the light emitting device with luminescent
material according to another embodiment of the invention.
Best Mode
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 consistent with this invention. 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 consistent with this
invention, 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. The phosphor in consistent with this invention may
include lead and/or copper doped aluminate type compounds, lead and/or copper doped
silicates, lead and/or copper doped antimonates , lead and/or copper doped germanates,
lead and/or copper doped germanate-silicates, lead and/or copper doped phosphates, or
any 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
consistent with this invention, the light is in a visible light range after the conversion. P
hosphor 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. Patent No.
6,482,664, which is hereby incorporated by reference in its entirety.
Phosphor 3 may comprise lead and/or copper doped chemical compound(s).
Phosphor 3 may include one or more single chemical compounds. The single
compound may have an emission peak of, for example, from about 440nm to about
500nm, from about 500nm to about 590nm, or from about 580nm to 700nm. Phosphor
3 may include one or more single phosphors, which may have an emission peak as ex-
emplified 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 consistent with this invention, more than
one light emitting diodes that have different emission peaks can be mounted together.
Moreover, if the mixture ratio of phosphors is adjusted properly, specific color of light,
color temperature, and CRI can be provided.
As described above, if the light emitting diode 6 and the compound included in
phosphor 3 are properly controlled then desired color temperature or specific color co-
ordination 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 90. Therefore, the light emitting devices consistent with this
invention may be used for electronic devices such as home appliances, stereos,
telecommunication devices, and for interior/exterior custom displays. The light
emitting devices consistent with this invention 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 consistent with this invention. A top -type
package light emitting device consistent with this invention 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 peak. 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 in consistent with this invention may include
lead and/or copper doped aluminate type compounds, lead and/or copper doped
silicates, lead and/or copper doped antimonates, lead and/or copper doped germanates,
lead and/or copper doped germanate-silicates, lead and/or copper doped phosphates, or
any combination thereof.
In one embodiment consistent with this invention, 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 consistent with this invention. 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 doped 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 consistent with this invention, 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 consistent with this invention. 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 frame 74 may protrude from
housing 73.
One or more light emitting diodes may be mounted 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. 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 consistent with this invention.
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.
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 Fig. 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 consistent with this invention, 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 doped components.
A light emitting device for high power consistent with this invention 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 consistent with this invention is not limited to the
structures described above, and the structures can be modified depending on the char-
acteristics of light emitting diodes, phosphor, wavelength of light, and also ap-
plications. Moreover, new part can be added to the structures.
An exemplary phosphor consistent with this invention is as follows.
In the following examples and description, M', M", M'", M"", M""' and M"""
are to be construed similar to M1, M2, M3, M4, M5 and M6 respectively.
(Phosphor)
Phosphor in consistence with this invention may include lead and/or copper doped
chemical compounds. The phosphor may be excited by UV and/or visible light, for
example, blue light. The compound may include Aluminate, Silicate, Antimonate,
Germanate, Germanate-silicate, or Phosphate type compounds.
Aluminate type compounds may comprise compounds having formula (1), (2),
and/or (5)
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, J, and/or any combination
thereof; 0
h
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, J, and any combination thereof; 0
The preparation of copper as well as lead doped 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 Sr Al O :Eu (3)
0.02 3.98 14 25
Starting materials: CuO, SrCO Al(OH), Eu O , and/or any combination thereof.
3, 3 2 3
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., H BO .
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 doped Eu -activated aluminate compared with Eu -activated
aluminate without copper at about 400 nm excitation wavelength
Preparation of the luminescent material having formula (4)
Pb Sr Al O :Eu (4)
0.05 3.95 14 25
Starting materials: PbO, SrCO , Al O , Eu O , and/or any combination thereof.
3 2 3 2 3
The starting materials in form of very pure oxides, carbonates, or other components
which may decompose thermically into oxides, may be mixed in stoichiometric
proportion together with small amounts of flux, for example, H BO . 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 doped Eu -activated aluminate compared with Eu -activated
aluminate without lead at about 400 nm excitation wavelength
Table 3: optical properties of some copper and/or lead doped aluminates excitable
by long wave ultraviolet and/or by visible light and their luminous density in % at 400
nm excitation wavelength
a(M'O) • b(M"0) • c(Al O ) • d(Mm O ) • e(Mm,0 ) • f (M O ) (5)
Zt J A j z* A y
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; NT" 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
Example of preparation:
Preparation of the luminescent material having formula (6)
Cu Sr Al Si O : Eu (6)
0.05 0.95 1.9997 0.0003 4
Starting materials: CuO, SrCO , Al O , SiO , Eu O , and/or any combination
° 3 2 3 2 2 3 J
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, A1F . 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 doped Eu +-activated aluminate compared with Eu2+-activated
aluminate without copper at about 400 nm excitation wavelength
Preparation of the luminescent material having formula (7)
Cu BaMg Al O : Eu (7)
0.12 "1.88 16 27
Starting materials: CuO, MgO, BaCO , Al(OH) Eu O , 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, A1F . 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 doped Eu +-activated aluminate compared with copper not doped
Eu +-activated aluminate at 400 nm excitation wavelength
Preparation of the luminescent material having formula (8)
Pb Sr AlO :Eu (8)
0.1 0.9 2 4
Starting materials: PbO, SrCO , Al(OH), Eu O , and/or any combination thereof.
3 3 2 3
The starting materials in form of, for example, pure oxides, hydroxides, and/or
carbonates may be mixed in stochiometric proportions together with small amounts of
flux, for example , H BO . 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 doped Eu +-activated aluminate compared with Eu +-activated
aluminate without lead at about 400 nm excitation wavelength
Results obtained in regard to copper and/or lead doped aluminates are shown in
table 7.
Table 7: optical properties of some copper and/or lead doped aluminates excitable
by long wave ultraviolet and/or by visible light and their luminous density in % at 400
nm excitation wavelength
A lead and/or copper doped silicates having formula (9)
a(M,0)-b(M"0)-c(M,"X)-d(M'" 0>e(M"" O >f(M'"" O )-g(SiO )• h(M O )
2 23 °P 2 xy
(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, J,
and any combination thereof; 0
f
Example of preparation:
Preparation of the luminescent material having formula (10)
Cu Sr Ca SiO : Eu (10)
0.05 1.7 0.25 4
Starting materials: CuO, SrCO CaCO , SiO , Eu O , 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, NH CI.
4
The mixture may be fired in an alumina crucible at about 1,200°C in an inert gas
atmosphere (e.g., N 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 doped Eu ""-activated silicate compared with Eu +-activated silicate
without copper at about 400 nm excitation wavelength
Preparation of the luminescent material having formula (11):
Cu Ba Zn Mg Si O : Eu (11)
0.2 2 0.2 ° 0.6 2 7
Starting materials: CuO, BaCO , ZnO, MgO, SiO , Eu O , 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,
NH CI. In a first step the mixture may be fired in an alumina crucible at about 1,100°C
4
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 doped Eu +-activated silicate compared with Eu +-activated silicate
without copper at 400 nm excitation wavelength
Preparation of the luminescent material having formula (12)
Pb Ba Sr Si Ge O : Eu (12)
0.1 0.95 0.95 0.998 0.002 4
Starting materials: PbO, SrCO , BaCO SiO , GeO Eu O , and/or any combination
thereof
The starting materials in the form of oxides and/or carbonates may be mixed in sto-
ichiometric proportions together with small amounts of flux, for example, NH CI. The
4
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 doped Eu2+-activated silicate compared with Eu2+-activated silicate
without lead at about 400 nm excitation wavelength
Preparation of the luminescent material having formula (13)
Pb Sr SiOCl : Eu (13)
0.25 3.75 3 8 4
Starting materials : PbO, SrCO , SrCl SiO , Eu O , and any combination thereof.
3 2, 2 2 3
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,
NH CI. The mixture may be fired in an alumina crucible in a first step at about 1,100
4
°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 doped Eu +-activated chlorosilicate compared with Eu +-activated
chlorosilicate without lead at 400 nm excitation wavelength
Results obtained with respect to copper and/or lead doped silicates are shown in
table 12.
Table 12: optical properties of some copper and/or lead doped 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
With lead and/or copper doped antimonates having formula (14)
a(M'O) • b(M" O) • c(M"X) • d(Sb 0 ) • e(M'"0) • f(M"" O ) (14)
2 2 5 x y
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, J, and/or any
combination thereof; 0
Examples of preparation:
Preparation of the luminescent material having formula (15)
Cu Mg Li SbO :Mn (15)
0.2 ° 1.7 0.2 2 7
Starting materials: CuO, MgO, Li O, Sb O , MnCO , 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 doped antimonate compared with antimonate without copper at
about 400 nm excitation wavelength
Preparation of the luminescent material having formula (16)
Pb Ca Sr Sb 0 (16)
0.006 0.6 0.394 2 6
Starting materials: PbO, CaCO , SrCO Sb O , and/or any combination thereof.
The starting materials in the form of oxides and/or carbonates may be mixed in sto-
ichiometric 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 doped antimonate compared with antimonate without lead at 400 nm
excitation wavelength
Results obtained in respect to copper and/or lead doped antimonates are shown in
table 15.
Table 15: optical properties of some copper and/or lead doped antimonates
excitable by long wave ultraviolet and/or by visible light and their luminous density in
% at about 400 nm excitation wavelength
Lead and/or copper doped germanates and/or a germanate-silicates having formula
(17)
(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, J, and/or any combination thereof; 0
0
Example of preparation:
Preparation of the luminescent material having formula (18)
Pb Ca Zn Ge Si 0 : Mn (18)
0.004 1.99 0.006 0.8 0.2 4
Starting materials: PbO, CaCO , ZnO, GeO , SiO , MnCO , and/or any
combination thereof,
The starting materials in the form of oxides and/or carbonates may be mixed in sto-
ichiometric proportions together with small amounts of flux, for example, NH CI. In a
4
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 doped Mn-activated germanate compared with Mn-activated
germanate without lead at about 400 nm excitation wavelength
Preparation of the luminescent material having formula (19)
Cu Sr Ge Si O : Mn (19)
0.46 0.54 0.6 0.4 3
Starting materials : CuO, SrCO , GeO , SiO , MnCO , and/or any combination
thereof
The starting materials in the form of oxides and/or carbonates may be mixed in sto-
ichiometric proportions together with small amounts of flux, for example, NH CI. In a
4
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 doped Mn-activated germanate-silicate compared with Mn-
activated germanate-silicate without copper at 400 nm excitation wavelength
Table 18: optical properties of some copper and/or lead doped germanate-silicates
excitable by long wave ultraviolet and/or by visible light and their luminous density in
% at about 400 nm excitation wavelength
Lead and/or copper doped phosphates having formula (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, Tb, and/or any
combination thereof; X may be F, Cl, Br, J, and/or any combination thereof; 0
0
and 1
Examples of preparation:
Preparation of the luminescent material having formula (21)
Cu Ca (PO)Cl:Eu (21)
0.02 4.98 4 3
Starting materials: CuO, CaCO , Ca (PO ), CaCl, Eu O , and/or any combination
3342 223
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 doped Eu +-activated chlorophosphate compared with Eu + -
activated chlorophosphate without copper at about 400 nm excitation wavelength
Table 20: copper and/or lead doped phosphates excitable by long wave ultraviolet
and/or by visible light and their luminous density in % at about 400 nm excitation
wavelength
Meanwhile , the phosphor of the light emitting device consistent with this
invention can comprise aluminate, silicate, antimonate, gcrmanate, phosphate type
chemical compound, and any combination thereof.
Fig. 6 is a one of the embodiment's emission spectrum according to the invention,
which the phosphor is used for the light emitting device. The embodiment may have a
light emitting diode with 405nm wavelength and the phosphor, which is mixture of the
selected multiple chemical compounds in proper ratio. The phosphor may be composed
of Cu BaMg Al O : Eu which may have peak wavelength at about 45 lnm, Cu
0.05 °1.95 16 27 J r a fl m
Sr Ca SiO : Eu which may have peak wavelength at 586nm, Pb Ca Sr Sb O
1.5 0.47 4 r a 0.006 0.6 0.394 2 6
: Mn + which may have peak wavelength at about 637nm, Pb Ba Zn Si Zr O
J 0.15 1.84 0.01 0.99 0.01 4
: Eu which may have peak wavelength at around 512nm, and Cu Sr Al O : Eu
"^ 0.2 3.8 14 25
which may have peak wavelength at about 494nm.
In such an embodiment, part of the initial about 405nm 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 Fig. 6, the light emitting device convert the 1st UV light of
405nm 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 according to the invention,
which the phosphor is applied for the light emitting device. The embodiment may have
a light emitting diode with about 455nm wavelength and the phosphor, which is
mixture of the selected multiple chemical compounds in proper ratio.
The phosphor is composed of Cu Sr Ca SiO : Eu which may have peak
r r 0.05 1.7 0.25 4 J r
wavelength at about 592nm, Pb Ba Sr Si Ge O : Eu which may have peak
° 0.1 0.95 0.95 0.998 0.002 4 J r
wavelength at about 527nm, and Cu Li Sr Ba SiO : Gd, Eu which may have
c 0.05 0.002 1.5 0.448 4 J
peak wavelength at about 557nm.
In such an embodiment, part of the initial about 455nm wavelength emission light
from the light emitting diode is absorbed by the phosphor, and it is converted to longer
2nd wavelength. The 1st and 2n light is mixed together and the desire emission is
produced. As the shown Fig. 7, the light emitting device convert the 1st blue light of
about 455nm 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 according to the invention 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 or about 8,000K or about 10,000K and superior color
rendering index more than about 90 can be realized by using the lead and/or copper
doped chemical compounds containing rare earth elements.
Industrial Applicability
In such a wavelength conversion light emitting device is capable of applying on
mobile phone, note book and electronic devices such as home appliance, stereo,
telecommunication products, but also for custom display's key pad and back light ap-
plication. Moreover, it can be applied for automobile, medical instrument and il-
lumination products.
According to the invention, it is also able to provide a wavelength conversion light
emitting device with stability 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 of Embodiments, with each claim standing on its own as
a separate preferred embodiment of the invention.
WE CLAIM:
1. A light emitting device, comprising:
a substrate;
a plurality of electrodes provided on the substrate;
a light emitting diode configured to emit light, the light emitting diode being provided
on one of the plurality of electrodes;
a phosphor configured to change a wavelength of the light, the phosphor substantially
covering at least a portion of the light emitting diode; and
an electrically conductive device configured to connect the light emitting diode with
another of the plurality of electrodes,
wherein said phosphor comprises an aluminate containing lead and/or copper, a
silicate containing lead and/or copper, an antimonate containing lead and/or copper, a
germanate containing lead and/or copper, a germanate-silicate containing lead and/or copper,
a phosphate containing lead and/or copper, or any combination thereof.
2. The light emitting device as claimed in claim 1, wherein the phosphor comprises a
compound having formula (1)
wherein
M1 is Pb, Cu, or any combination thereof;
M2 is Li, Na, K, Rb, Cs, Au, Ag or any combination thereof;
M3 is Be, Mg, Ca, Sr, Ba, Zn, Cd, Mn or any combination thereof;
M4 is Sc, B, Ga, In, and/or any combination thereof;
M5 is Si, Ge, Ti, Zr, Mn, V, Nb, Ta, W, Mo, or any combination thereof;
M6 is Bi, Sn, Sb, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, or any
combination thereof;
X is F, Cl, Br, I, or any combination thereof;
0
0
0
0
0
0
0
0
1
1
1
l
3. The light emitting device as claimed in claim 1, wherein the phosphor comprises a
compound having formula (2)
wherein
M1 is Pb, Cu, or any combination thereof;
M2 is Li, Na, K, Rb, Cs, Au, Ag or any combination thereof;
M3 is Be, Mg, Ca, Sr, Ba, Zn, Cd, Mn or any combination thereof;
M4 is Bi, Sn, Sb, Sc, Y, La, In, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, or
any combination thereof;
X is F, Cl, Br, I, or any combination thereof;
0
0
0
0
0
0
0
0
l
l
4. The light emitting device as claimed in claim 1, wherein the phosphor comprises a
compound having formula (5)
wherein
M1 is Pb, Cu, or any combination thereof;
M2 is Be, Mg, Ca, Sr, Ba, Zn, Cd, Mn, or any combination thereof;
M3 is B, Ga, In, or any combination thereof;
M4 is Si, Ge, Ti, Zr, Hf, or any combination thereof;
M5 is Bi, Sn, Sb, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, or any
combination thereof;
0
0
0
0
0
0
l
l
5. The light emitting device as claimed in claim 1, wherein the phosphor comprises a
compound having formula (9)
wherein
M1 is Pb, Cu, or any combination thereof;
M2 is Be, Mg, Ca, Sr, Ba, Zn, Cd, Mn or any combination thereof;
M3 is Li, Na, K, Rb, Cs, Au, Ag or any combination thereof;
M3 is Al, Ga, In, or any combination thereof;
M5 is Ge, V, Nb, Ta, W, Mo, Ti, Zr, Hf, or any combination thereof;
M6 is Bi, Sn, Sb, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, or any
combination thereof;
0
0
0
0
0
0
0
0
1
1
1
1
6. The light emitting device as claimed in claim 1, wherein the phosphor comprises a
compound having formula (14)
wherein
M1 is Pb, Cu, or any combination thereof;
M2 is Li, Na, K, Rb, Cs, Au, Ag or any combination thereof;
M3 is Be, Mg, Ca, Sr, Ba, Zn, Cd, Mn or any combination thereof;
M4 is Bi, Sn, Sc, Y, La, Pr, Sm, Eu, Tb, Dy, Gd, or any combination thereof;
X is F, Cl, Br, I, or any combination thereof;
0
0
0
0
0
0
1
l
7. The light emitting device as claimed in claim 1, wherein the phosphor comprises a
compound having formula (17)
wherein
M1 is Pb, Cu, or any combination thereof;
M2 is Li, Na, K, Rb, Cs, Au, Ag or any combination thereof;
M3 is Be, Mg, Ca, Sr, Ba, Zn, Cd, or any combination thereof;
M4 is Sc, Y, B, Al, La, Ga, In, or any combination thereof;
M5 is Si, Ti, Zr, Mn, V, Nb, Ta, W, Mo, or any combination thereof;
M6 is Bi, Sn, Pr, Sm, Eu, Gd, Dy, or any combination thereof;
X is F, Cl, Br, I, or any combination thereof;
0
0
0
0
0
0
0
0
l
1
l
l
8. The light emitting device as claimed in claim 1, wherein the phosphor comprises a
compound having formula (20)
wherein
M1 is Pb, Cu, or any combination thereof;
M2 is Li, Na, K, Rb, Cs, Au, Ag or any combination thereof;
M3 is Be, Mg, Ca, Sr, Ba, Zn, Cd, Mn, or any combination thereof;
M4 is Sc, Y, B, Al, La, Ga, In, or any combination thereof;
M5 is Si, Ge, Ti, Zr, Hf, V, Nb, Ta, W, Mo, or any combination thereof;
X is F, Cl, Br, I, or any combination thereof;
0
0
0
0
0
0
0
0
1
l
9. A light emitting device as claimed in any one of claims 1 to 8, wherein the phosphor
comprises one or more single compounds or any combination thereof.
10. A light emitting device as claimed in any one of claims 1 to 9 comprising a sealing
material configured to cover the light emitting diode and the phosphor.
11. A light emitting device as claimed in claim 10, wherein the phosphor is distributed in
the sealing material.
12. A light emitting device as claimed in any one of claims 1 to 11, wherein the phosphor
is mixed with a hardening material.
13. The light emitting device as claimed in any one of claims 1 to 12, wherein the light
emitting diode comprises a plurality of light emitting diodes.
14. The light emitting device as claimed in any one of claims 1 to 13 comprising
electrically conductive paste provided between the light emitting diode and the one of the
plurality of electrodes.
15. The light emitting device as claimed in any one of claims 1 to 14 comprising a
reflector configured to reflect the light from the light emitting diode.
ABSTRACT
LIGHT EMITTING DEVICE
A light emitting device is disclosed. The light emitting device comprises: a substrate;
a plurality of electrodes provided on the substrate; a light emitting diode configured to emit
light, the light emitting diode being provided on one of the plurality of electrodes; a phosphor
configured to change a wavelength of the light, the phosphor substantially covering at least a
portion of the light emitting diode; and an electrically conductive device configured to
connect the light emitting diode with another of the plurality of electrodes, wherein said
phosphor comprises an aluminate containing lead and/or copper, a silicate containing lead
and/or copper, an antimonate containing lead and/or copper, a germanate containing lead and/
or copper, a germanate-silicate containing lead and/or copper, a phosphate containing lead
and/or copper, or any combination thereof. |