U.S. patent application number 12/129644 was filed with the patent office on 2008-09-18 for photoluminescent material of light-emitting diode package structure.
This patent application is currently assigned to LIGHTHOUSE TECHNOLOGY CO., LTD. Invention is credited to Chih-Chin Chang, Hsiang-Cheng Hsieh, Teng-Huei Huang.
Application Number | 20080224096 12/129644 |
Document ID | / |
Family ID | 37034519 |
Filed Date | 2008-09-18 |
United States Patent
Application |
20080224096 |
Kind Code |
A1 |
Chang; Chih-Chin ; et
al. |
September 18, 2008 |
PHOTOLUMINESCENT MATERIAL OF LIGHT-EMITTING DIODE PACKAGE
STRUCTURE
Abstract
An LED package structure including a carrier, an LED chip, an
encapsulant and a PL material is provided, wherein the LED chip is
disposed on the carrier for emitting light. The encapsulant
encapsulates the LED chip. The PL material is distributed in the
encapsulant. The PL material is suitable for being excited by the
light emitted from the LED chip and scattering the light. Moreover,
the present invention provides a novel PL material with a molecular
formula of
W.sub.mMo.sub.n(Y,Ce,Tb,Gd,Sb).sub.3+t+u(Al,Ga,Tl,In,B).sub.5+u+2v(O,S,Se-
).sub.12+2t+3u+3v+3m+3n:Ce.sup.3+,Tb.sup.3+, wherein 0<t<5
and 0<m, n, u, v<15.
Inventors: |
Chang; Chih-Chin; (Hsinchu,
TW) ; Hsieh; Hsiang-Cheng; (Taoyuan County, TW)
; Huang; Teng-Huei; (Hsinchu County, TW) |
Correspondence
Address: |
JIANQ CHYUN INTELLECTUAL PROPERTY OFFICE
7 FLOOR-1, NO. 100, ROOSEVELT ROAD, SECTION 2
TAIPEI
100
TW
|
Assignee: |
LIGHTHOUSE TECHNOLOGY CO.,
LTD
Hsinchu County
TW
|
Family ID: |
37034519 |
Appl. No.: |
12/129644 |
Filed: |
May 29, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11160287 |
Jun 17, 2005 |
|
|
|
12129644 |
|
|
|
|
Current U.S.
Class: |
252/301.5 ;
257/E33.074; 423/263 |
Current CPC
Class: |
H01L 2933/0091 20130101;
C09K 11/7774 20130101; H01L 2924/181 20130101; H01L 2224/8592
20130101; H01L 2924/00012 20130101; H01L 2924/181 20130101; H01L
33/502 20130101; H01L 33/56 20130101; H01L 2224/49107 20130101;
H01L 2224/48257 20130101; H01L 2224/48247 20130101 |
Class at
Publication: |
252/301.5 ;
423/263 |
International
Class: |
C09K 11/78 20060101
C09K011/78; C09K 11/88 20060101 C09K011/88; C09K 11/84 20060101
C09K011/84; C01F 17/00 20060101 C01F017/00; C09K 11/80 20060101
C09K011/80 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 24, 2005 |
TW |
94109063 |
Claims
1. A photoluminescent material with a molecular formula of
W.sub.mMo.sub.n(Y,Ce,Tb,Gd,Sb).sub.3+t+u(Al,Ga,Tl,In,B).sub.5+u+2v(O,S,Se-
).sub.12+2t+3u+3v+3m+3n:Ce.sup.3+,Tb.sup.3+, wherein 0<t<5
and 0<m, n, u, v<15.
2. The photoluminescent material of claim 1 with the molecular
formula of
W.sub.mMo.sub.n(Y,Ce,Tb,Gd,Sb).sub.3+t+u(Al,Ga,Tl,In,B).sub.5+u+2v(O,S,Se-
).sub.12+2t+3u+3v+3m+3n:Ce.sup.3+,Tb.sup.3+, wherein 0<t<5
and 0<m, n, u, v<15, is a mixture.
3. The photoluminescent material of claim 1 with the molecular
formula of
W.sub.mMo.sub.n(Y,Ce,Tb,Gd,Sb).sub.3+t+u(Al,Ga,Tl,In,B).sub.5+u+2v(O,S,Se-
).sub.12+2t+3u+3v+3m+3n:Ce.sup.3+,Tb.sup.3+, wherein 0<t<5
and 0<m, n, u, v<15, is a sinter.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional of an application Ser. No.
11/160,287, filed on Jun. 17, 2005, now pending, which claims the
priority benefit of Taiwan application serial no. 94109063, filed
on Mar. 24, 2005. The entirety of the above-mentioned patent
applications is hereby incorporated by reference herein and made a
part of this specification.
BACKGROUND OF THE INVENTION
[0002] 1. Field of Invention
[0003] The present invention relates to an LED (light-emitting
diode) package structure. More particularly, it relates to an LED
package structure comprising a photoluminescent diffuser
material.
[0004] 2. Description of the Related Art
[0005] As LED luminous efficiency has continued to enhance in
recent years, LEDs have gradually replaced fluorescent lamps and
incandescent lamps in some applications, such as fast-responding
scanner light sources, LCD (Liquid Crystal Display) back light
sources, automobile dashboard lighting, traffic lights, and general
lighting devices. In comparison with conventional light bulbs, LEDs
have absolute predominance because of features, such as compact
size, durability, low voltage/current operation, break-resistance,
zero heat radiation during illumination, no mercury (and therefore
no environmental pollution) and high luminous efficiency (energy
saving). In terms of production technologies and applications
today, white LED draws the most attention among LEDs' various
lighting colors.
[0006] White light is a type of light blended from a plurality of
colors of light. The white light visible to human eyes comprises at
least two colors of light in different wavelengths. For example,
blue light and yellow light are blended to form a dual-wavelength
white light; or red light, green light and blue light are blended
to form a triple-wavelength white light. Currently white LEDs are
fabricated in three methods. First, there is a so-called
triple-wavelength method, wherein an LED chip set is comprised of a
red LED chip, a green LED chip and a blue LED chip. Uniform white
light is formed by adjusting respective currents passing through
the three chips. This mode features a high luminous efficiency
along with a higher production cost. Second, there is a so-called
dual-wavelength method, wherein an LED chip set is comprised of a
blue LED chip and a yellow LED chip. By adjusting the respective
currents of the two chips, uniform white light is formed. This
method is characterized in good luminous efficiency and a lower
production cost. Additionally, there is a third method, wherein
white light is formed by blending blue light formed by a blue LED
and yellow light formed by exciting blue light to form yellow
phosphor. The third mode features a simpler production process,
lower luminous efficiency and a lower cost. Therefore, currently,
most white LEDs are based on the third method. Namely, the white
light is formed by means of the blue light and the yellow phosphor
excited by the blue light.
[0007] FIG. 1 is a schematic drawing of a conventional white LED
package structure. In FIG. 1, the conventional white LED package
structure mainly comprises package lead pins 100, a blue LED chip
102, an inner encapsulant 104 and an outer encapsulant 106, wherein
the blue LED chip 102 is disposed on the package lead pins 100 and
electrically connected to the package lead pins 100 via two
soldering wires 108; the inner encapsulant 104 comprises yellow
phosphor, covering the blue LED chip 102; an outer encapsulant 106
is used to cover part of the package lead pins 100, the blue LED
chip 102 and the inner encapsulant 104. The aforesaid white LED
uses the blue light emitted by the blue LED chip 102 to excite the
inner encapsulant 104 to form a dual-wavelength white light, which
is blended by the blue light and the yellow light.
[0008] FIG. 2 is a schematic drawing of another conventional white
LED package structure. In comparison with FIG. 1, the major
improvement of the white LED is an additional diffusion layer 110
applied to cover the inner encapsulant 104. The diffusion layer 110
comprises transparent glue in which transparent particles or air
bubbles are distributed. The transparent particles or air bubbles
in the diffusion layer 110 repeatedly refract the light rays, which
enables the tone of the blended light to be more uniform.
[0009] However, to obtain a better light interfusing effect, the
fluorescent powder on the above-described inner encapsulant 104 and
the size and distributed density of transparent particles or air
bubbles in the diffusion layer 110 must be well matched. Since too
many factors can influence the light interfusing effect,
practically it is difficult to some extent to produce and control
the light interfusing effect.
[0010] To get a detailed understanding of the above-described LED
package structure, U.S. Pat. No. 5,998,925 and the ROC patent PN
383508 can be used for reference.
SUMMARY OF THE INVENTION
[0011] According, the present invention is directed to provide an
LED package structure to further enhance the light infusing effect
thereof.
[0012] According, the present invention is to provide a cold
cathode fluorescent lamp, wherein a photoluminescent material (PL
material) is used to replace the conventional fluorescent layer and
diffusion layer to enhance the light infusing effect thereof.
[0013] According, the present invention is to provide a PL material
which is different from conventional fluorescent powder but
suitable for the LED package structure and cold cathode fluorescent
lamps to produce better light infusing effect.
[0014] The present invention provides an LED package structure,
which mainly comprises a carrier, an LED chip, an encapsulant, and
a PL material, wherein the LED chip is disposed on the carrier to
emit light rays; the encapsulant is used to encapsulate the LED
chip on the carrier; and the PL material is distributed in the
encapsulant, wherein the photoluminescent material is adapted to be
excited by the light emitted from the LED chip and to scatter the
light.
[0015] According to one embodiment of the present invention, the
carrier is, for example, a printed circuit board (PCB) comprising a
chip-holding cell for disposing the LED chip. The LED chip is
electrically connected to the PCB.
[0016] According to one embodiment of the present invention, the
carrier is, for example, a package frame. The LED chip is
electrically connected to the package frame via two soldering
wires. Besides, the LED chip is, for example, a blue LED chip.
[0017] According to one embodiment of the present invention, the
encapsulant comprises an inner encapsulant and an outer
encapsulant, wherein the inner encapsulant encapsulates the LED
chip and the PL material is distributed in the inner encapsulant,
and the outer encapsulant encapsulates the inner encapsulant and a
part of the carrier.
[0018] According to one embodiment of the present invention, the
molecular formula of the PL material can be given by:
W.sub.mMo.sub.n(Y,Ce,Tb,Gd,Sb).sub.3+t+u(Al,Ga,Tl,In,B).sub.5+u+2v(O,S,S-
e).sub.12+2t+3u+3v+3m+3n:Ce.sup.3+,Tb.sup.3+,
wherein 0<t<5 and 0<m, n, u, v<15. The aforesaid PL
material with said molecular formula of:
W.sub.mMo.sub.n(Y,Ce,Tb,Gd,Sb).sub.3+t+u(Al,Ga,Tl,In,B).sub.5+u+2v(O,S,Se-
).sub.12+2t+3u+3v+3m+3n:Ce.sup.3+,Tb.sup.3+, wherein 0<t<5
and 0<m, n, u, v<15, is a mixture or a sinter. In addition,
the largest particle diameter is smaller than 30 microns and the
average particle diameter is smaller than 10 microns.
[0019] According to one embodiment of the present invention, the PL
material comprises a fluorescent material and a diffusion material.
The particle diameter of the fluorescence material is smaller than
25 microns.
[0020] The present invention further provides an alternative cold
cathode fluorescent lamp comprising a fluorescent lamp, discharging
gas, PL material and an electrode set, wherein the discharging gas
is filled in the fluorescent lamp, the PL material is disposed on
the inner wall of the lamp and the electrode set comprises an anode
and a cathode with the anode disposed at one end of the light tube
and the cathode disposed at the other.
[0021] According to one embodiment of the present invention, the
molecular formula of the PL material can be given by:
W.sub.mMo.sub.n(Y,Ce,Tb,Gd,Sb).sub.3+t+u(Al,Ga,Tl,In,B).sub.5+u+2v(O,S,Se-
).sub.12+2t+3u+3v+3m+3n:Ce.sup.3+,Tb.sup.3+, wherein 0<t<5
and 0<m, n, u, v<15. The PL material with the molecular
formula of
W.sub.mMo.sub.n(Y,Ce,Tb,Gd,Sb).sub.3+t+u(Al,Ga,Tl,In,B).sub.5+u+2v(O,S,Se-
).sub.12+2t+3u+3v+3m+3n:Ce.sup.3+,Tb.sup.3+, wherein 0<t<5
and 0<m, n, u, v<15 is a mixture or a sinter. In addition,
the PL material comprises a fluorescent material and a diffusion
material adhered by the fluorescent material.
[0022] The present invention also provides an alternative PL
material. The molecular formula of the PL material can be given
by:
W.sub.mMo.sub.n(Y,Ce,Tb,Gd,Sb).sub.3+t+u(Al,Ga,Tl,In,B).sub.5+u+2v(O,S,Se-
).sub.12+2t+3u+3v+3m+3n:Ce.sup.3+,Tb.sup.3+, wherein 0<t<5
and 0<m, n, u, v<15. Moreover, the PL material with the
molecular formula of
W.sub.mMo.sub.n(Y,Ce,Tb,Gd,Sb).sub.3+t+u(Al,Ga,Tl,In,B).sub.5+u+2v(O,S,Se-
).sub.12+2t+3u+3v+3m+3n:Ce.sup.3+,Tb.sup.3+, wherein 0<t<5
and 0<m, n, u, v<15, can be a mixture or a sinter.
[0023] The present invention uses a PL material to replace the
conventional fluorescent layer and diffusion layer for light
conversion and a light interfusing effect. Thus, there are no more
match problems among the variants in the prior art, such as the
materials of the fluorescent layer and diffusion layer, the
particle size and the particle distribution density, and the like.
Besides, the overall procedure for fabricating LED packages is
effectively simplified along with a lower production cost and
better light interfusing effect.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The accompanying drawings are included to provide a further
understanding of the invention, and are incorporated in and
constitute a part of this specification. The drawings illustrate
embodiments of the invention and, together with the description,
serve to explain the principles of the invention.
[0025] FIG. 1 is a schematic drawing of a conventional white LED
package structure.
[0026] FIG. 2 is a schematic drawing of another conventional white
LED package structure.
[0027] FIG. 3 is a schematic drawing of a white LED package
structure according to a first embodiment of the present
invention.
[0028] FIG. 4A and FIG. 4B are schematic diagrams showing a PL
material.
[0029] FIG. 5A and FIG. 5B are schematic diagrams showing an
alternative PL material.
[0030] FIG. 6 and FIG. 7 are schematic drawings of white LED
packages structure according to a second embodiment of the present
invention.
[0031] FIG. 8 is a schematic drawing of a cold cathode fluorescent
lamp according to a third embodiment of the present invention.
DESCRIPTION OF THE EMBODIMENTS
The First Embodiment
[0032] FIG. 3 is a schematic drawing of an LED package structure
according to the first embodiment of the present invention. In FIG.
3, the LED package structure in the first embodiment of the present
invention mainly comprises a carrier 200, an LED chip 210, an
encapsulant 220 and a PL material 230, wherein the LED chip 210 is
disposed on the carrier 200 to emit light; the encapsulant 220
encapsulates most of the carrier 200 and the LED chip 210 thereon;
and the PL material 230 is evenly distributed in the encapsulant
220. The PL material layer 230 is suitable to be excited by the
light emitted from the LED chip 210 and to scatter the light.
[0033] In the first embodiment, the carrier 200 is, for example,
package lead pins 200' as shown in FIG. 3. The package lead pins
200' comprise a first lead pin 202 and a second lead pin 204. On
the top of the first lead pin 202 is a carrier pad 206, comprising
a chip-holding cell 208. The chip-holding cell 208 is of a concave
shape suitable to hold the LED chip 210.
[0034] The LED chip 210 is disposed in the chip-holding cell 208 of
the carrier pad 206 to emit light. In the first embodiment, the LED
chip 210 is, for example, a blue LED chip. The surface of the LED
chip 210 has electrodes 212, comprising a cathode and an anode,
wherein the cathode is electrically connected to the first lead pin
202 and the anode to the second lead pin 204 respectively via
soldering wires 209a and 209b.
[0035] The encapsulant 220 is used to encapsulate a portion of the
package lead pins 200', the LED chip 210, the PL material 230, and
the soldering wires 209a and 209b. The first lead pin 202 and the
second lead pin 204 protrude from the bottom of the encapsulant
220. The encapsulant 220 comprises an inner encapsulant 222 and an
outer encapsulant 224, wherein the inner encapsulant 222
encapsulates the LED chip 210, and the outer encapsulant 224
encapsulates the inner encapsulant 222 and a portion of the carrier
200.
[0036] Note that the PL material 230 in the present invention is
uniformly distributed in the inner encapsulant 222. The PL material
230 serves as both a fluorescent layer and a diffusion layer of the
prior art. That is, the PL material is not only excited by the
light emitted from the LED chip 210, but is also capable of
scattering the light. As a result, the light emitted from the LED
chip 210 and the light formed by excited PL material 230 are
blended more uniformly to further achieve a better light
interfusing effect. The PL material 230 is not limited to the
application of the inner encapsulant 222 in the first embodiment.
The PL material 230 is also applicable to other package, structure
or lightings which are based on the excited phosphor to produce
light. In all of these applications, a good light interfusing
effect can be achieved.
[0037] FIG. 4A and FIG. 4B are schematic diagrams showing a grain
of the PL material. In FIG. 4A and FIG. 4B, the grain of the PL
material 230 comprises a fluorescent material 230a and a diffusion
material 230b adhering to the fluorescent material 230a which is
distributed in the diffusion material 230b. As the incident light
emitted from the LED chip 210 enters the PL material 230, the
fluorescent material 230a inside the PL material 230 is excited and
produces a light in other wavelength. Besides, the diffusion
material 230b scatters the light onto other grains of the PL
material 230, enabling the LED package structure to produce a
better light interfusing effect. In FIG. 4B, there is a
transitional-phase 230c embracing the fluorescence material 230a.
The transitional-phase 230c may produced in certain condition when
fabricating the PL material 230.
[0038] In the first embodiment, the molecular formula of the PL
material 230 can be given by:
W.sub.mMo.sub.n(Y,Ce,Tb,Gd,Sb).sub.3+t+u(Al,Ga,Tl,In,B).sub.5+u+2v(O,S,Se-
).sub.12+2t+3u+3v+3m+3n:Ce.sup.3+,Tb.sup.3+, wherein 0<t<5
and 0<m, n, u, v<15. In FIG. 4A, to achieve a better light
interfusing effect, the largest particle diameter of PL material
Dmax is smaller than 30 microns, the average particle diameter
thereof is smaller than 10 microns, and the particle diameter of
fluorescent material Di is smaller than 25 microns. Moreover, the
PL material with the molecular formula of
W.sub.mMo.sub.n(Y,Ce,Tb,Gd,Sb).sub.3+t+u(Al,Ga,Tl,In,B).sub.5+u+2v(O,S,S-
e).sub.12+2t+3u+3v+3m+3n:Ce.sup.3+,Tb.sup.3+,
0<t<5 and 0<m, n, u, v<15, can be a mixture or a
sinter.
[0039] FIG. 5A and FIG. 5B are schematic diagrams showing a grain
of an alternative PL material 230. In FIG. 5A and FIG. 5B, the
grain of the PL material 230 comprises a fluorescent material 230a
and a diffusion material 230b. The difference between FIG. 5A and
FIG. 5B is that the diffusion material 230b of the PL material 230
is distributed in the fluorescent material 230a. The alternative PL
material 230 can also achieve the same light interfusing
effect.
[0040] It is known to those skilled in the art that the disclosed
PL material 230 is not limited to the aforesaid package structure.
In fact, the disclosed PL material 230 is also applicable to any
package structure based on the excited-phosphor mode to produce
light. To reach the goal, the original fluorescent layer needs to
be replaced by an inner encapsulant 222 and a PL material 230
distributed therein.
The Second Embodiment
[0041] FIG. 6 and FIG. 7 are schematic drawings of white LED
package structures according to the second embodiment of the
present invention. In FIG. 6, the structure in the second
embodiment is similar to that of the first embodiment. The
difference in the second embodiment is that the carrier 300 therein
is a printed circuit board (PCB) 300' on which the package is
disposed.
[0042] The LED package structure in the second embodiment mainly
comprises a PCB 300', an LED chip 310, an encapsulant 320 and a PL
material 330. The encapsulant 320 similarly comprises an inner
encapsulant 322 and an outer encapsulant 324, wherein the inner
encapsulant 322 encapsulates the LED chip 310, and the outer
encapsulant 324 encapsulates a portion of the PCB 300', the LED
chip 310, the inner encapsulant 322, the PL material 330 and the
soldering wires 314. When the encapsulant 320 comprises only an
outer encapsulant 324 without the inner encapsulant 322, the outer
encapsulant 324 can only comprise the PL material 330.
[0043] The LED chip 310 is disposed on the PCB 300'. Connection
pads 302 and electrodes 312 are disposed on the PCB 300' and the
LED chip 310, respectively. The electrodes 312 are connected to the
connection pads 302 on the PCB 300' through two soldering wires
314, so that the PCB 300' is electrically connected to the LED chip
310.
[0044] The inner encapsulant 322 is disposed on the PCB 300' and
covers the aforesaid LED chip 310. The PL material 330 is uniformly
distributed in the inner encapsulant 322 and comprises a
fluorescent material and a diffusion material adhering to the
fluorescent material. When the incidence light from the LED chip
310 enters the PL material 330, the fluorescent material therein is
excited and produces a light with a different wavelength. The
diffusion material scatters the light onto other particles of the
PL material to produce a better light interfusing effect. In the
second embodiment, the molecular formula of the PL material 330 can
be given by:
W.sub.mMo.sub.n(Y,Ce,Tb,Gd,Sb).sub.3+t+u(Al,Ga,Tl,In,B).sub.5+u+2v(O,S,Se-
).sub.12+2t+3u+3v+3m+3n:Ce.sup.3+,Tb.sup.3+, wherein 0<t<5
and 0<m, n, u, v<15. To achieve a better light interfusing
effect the largest particle diameter of the PL material 330 Dmax
is, similarly, smaller than 30 microns, the average particle
diameter thereof is smaller than 10 microns, and the particle
diameter of fluorescent material Di is smaller than 25 microns.
Moreover, the PL material with the molecular formula of
W.sub.mMo.sub.n(Y,Ce,Tb,Gd,Sc).sub.3+t+u(Al,Ga,Tl,In,B).sub.5+u+2v(O,S,Se-
).sub.12+2t+3u+3v+3m+3n:Ce.sup.3+,Tb.sup.3+, wherein 0<t<5
and 0<m, n, u, v<15, can be a mixture or a sinter.
[0045] In FIG. 7, to enhance the light-condensing effect of the LED
package structure, a chip-holding cell 304 is disposed in the PCB
300'. The chip-holding cell 304 is of a concave-cup shape suitable
for holding the LED chip 310. Moreover, a reflecting-film layer can
be plated on the sidewall of the chip-holding cell 304 as an option
of increasing the light-reflection effect.
The Third Embodiment
[0046] In the first and second embodiment of the present invention,
the PL material is used in the LED package structure. In addition,
the PL material can also be used in general cold cathode
fluorescent lamps to achieve a better light interfusing effect.
[0047] FIG. 8 is a schematic drawing of a cold cathode fluorescent
lamp according to the third embodiment of the present invention. In
FIG. 8, the cold cathode fluorescent lamp 400 comprises a light
tube 410, a discharging gas (not shown in the figure), a PL
material 420 and an electrode set 430, wherein the light tube 110
is properly filled with discharging gas, such as mercury vapor and
inert gas. The PL material 420 is applied on the inner wall of the
light tube 410. In addition, the electrode set 430 comprises both
an anode and a cathode individually disposed at two ends of the
light tube 410, respectively. The electrode set 430 is electrically
connected to a power supply (not shown in the figure).
[0048] When a bias voltage is applied to the electrode set 430, the
discharging gas in the light tube, such as the mercury vapor and
the inert gas, is excited to an excited state, then returns to a
steady state. While the discharging gas returns to the steady
state, the gas releases energy by emitting an ultraviolet light.
With the aforesaid mechanism, when the ultraviolet light released
by the discharging gas reaches the PL material 420 on the wall of
the light tube 410, the PL material comprising the fluorescent
material and the diffusion material adhering to the florescent
material emits a visible light to achieve lighting effect.
Meanwhile, the diffusion material adhering to the fluorescent
material scatters the light to produce a better light interfusing
effect. The limitations of the PL material molecular formula and
the particle size are the same as described in the first and second
embodiment, so it is not repeated.
[0049] To sum up, in the LED package structure of the present
invention, the aforesaid PL material is used to replace the
fluorescent layer and the diffusion layer of the prior art. The
molecular formula of the PL material 330 can be given by:
W.sub.mMo.sub.n(Y,Ce,Tb,Gd,Sb).sub.3+t+u(Al,Ga,Tl,In,B).sub.5+u+2v(O,S,S-
e).sub.12+2t+3u+3v+3m+3n:Ce.sup.3+,Tb.sup.3+,
wherein 0<t<5 and 0<m, n, u, v<15. The PL material is
not only excited by the light emitted from the aforesaid LED chip,
but also scatters the light. Thus, the light emitted from the LED
chip and the light excited by the PL material are blended more
uniformly to achieve a better light infusing effect.
[0050] It will be apparent to those skilled in the art that various
modifications and variations can be made to the structure of the
present invention without departing from the scope or spirit of the
invention. In view of the foregoing, it is intended that the
specification and examples to be considered as exemplary only, with
a true scope and spirit of the invention being indicated by the
following claims and their equivalents.
* * * * *