U.S. patent number RE43,200 [Application Number 12/029,220] was granted by the patent office on 2012-02-21 for high power light emitting diode package.
This patent grant is currently assigned to Samsung LED Co., Ltd.. Invention is credited to Kyung Taeg Han, Chang Wook Kim, Seon Goo Lee.
United States Patent |
RE43,200 |
Lee , et al. |
February 21, 2012 |
**Please see images for:
( Certificate of Correction ) ** |
High power light emitting diode package
Abstract
The invention relates to a high power LED package, in which a
package body is integrally formed with resin to have a recess for
receiving an LED chip. A first sheet metal member is electrically
connected with the LED chip, supports the LED chip at its upper
partial portion in the recess, is surrounded by the package body
extending to the side face of the package body, and has a heat
transfer section for transferring heat generated from the LED chip
to the metal plate of the board and extending downward from the
inside of the package body so that a lower end thereof is exposed
at a bottom face of the package body thus to contact the board. A
second sheet metal member is electrically connected with the LED
chip spaced apart from the first sheet metal member for a
predetermined gap, and extends through the inside of the package
body to the side face of the package body in a direction opposite
to the first sheet metal member. A transparent sealant is sealingly
filled up into the recess. The LED package raises thermal radiation
efficiency with a simplified structure in order to reduce the size
and thickness thereof.
Inventors: |
Lee; Seon Goo (Kyungki-do,
KR), Kim; Chang Wook (Kyungki-do, KR), Han;
Kyung Taeg (Hwasung, KR) |
Assignee: |
Samsung LED Co., Ltd.
(Gyunggi-do, KR)
|
Family
ID: |
37149804 |
Appl.
No.: |
12/029,220 |
Filed: |
February 11, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
11186971 |
Jul 22, 2005 |
7208772 |
Apr 24, 2007 |
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Foreign Application Priority Data
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Sep 1, 2004 [KR] |
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10-2004-69730 |
May 4, 2005 [KR] |
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10-2005-37421 |
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Current U.S.
Class: |
257/99; 257/676;
257/98; 257/E33.058; 257/E33.056; 257/E33.057; 257/693; 257/100;
257/E33.059; 257/692; 257/706; 257/696 |
Current CPC
Class: |
H01L
33/62 (20130101); H01L 2924/0002 (20130101); H01L
2924/12041 (20130101); H01L 33/60 (20130101); H01L
2924/0002 (20130101); H01L 2924/00 (20130101) |
Current International
Class: |
H01L
33/00 (20100101); H01L 23/48 (20100101); H01L
29/22 (20100101) |
Field of
Search: |
;257/98,99,100,676,672,675,696,698,697,706,692,693,E33.056,E33.057,E33.058,E33.059 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Parker; Kenneth
Assistant Examiner: Page; Dale E
Attorney, Agent or Firm: Lowe, Hauptman, Ham & Berner,
LLP
Claims
What is claimed is:
.[.1. A high power Light Emitting Diode (LED) package mounted on a
board, which includes a metal plate of a heat sink, an insulating
layer on the metal plate and a conductive pattern printed with
plural pattern lines on the insulating layer, the high power LED
package comprising: an LED chip; a package body integrally formed
with resin to have a recess for receiving the LED chip; a first
sheet metal member electrically connected with the LED chip while
supporting the LED chip at its upper partial portion in the recess,
the first sheet metal member surrounded by the package body and
extending to the side face of the package body, the first sheet
metal member having a heat transfer section for transferring heat
generated from the LED chip to the metal plate of the board and
extending downward from the inside of the package body so that a
lower end thereof is exposed at a bottom face of the package body
thus to contact the board; a second sheet metal member electrically
connected with the LED chip spaced apart from the first sheet metal
member for a predetermined gap, the second sheet metal member
extending through the inside of the package body to the side face
of the package body in a direction opposite to the first sheet
metal member; and a transparent sealant sealingly filled up into
the recess..].
.[.2. The high power LED package according to claim 1, wherein the
heat transfer section of the first sheet metal member is protruded
downward from the bottom face of the package body..].
.[.3. The high power LED package according to claim 1, wherein the
first and second sheet metal members each have at least one hole,
and the package body has a plurality of connecting posts that are
integrally formed and connected with the upper and lower portions
of the package body through the holes..].
.[.4. The high power LED package according to claim 1, wherein the
first sheet metal member is contacted with one electrode of the LED
chip, and further has an external terminal integrally formed
therewith to extend over the outside of the package body thereby
contacting one pattern line of the board, and wherein the second
sheet metal member is connected at one end of the recess-side with
the other electrode of the LED chip and extended at the other end
of the recess-side out of the package body, thereby contacting the
other pattern line of the board..].
.[.5. The high power LED package according to claim 1, wherein the
second sheet metal member is divided into a pair of first and
second terminals insulated from each other, in which the first
terminal is connected at one end with one electrode of the LED chip
and extended at the other end out of the package body, thereby
contacting one pattern line of the board, and wherein the second
terminal is connected at one end with the other electrode of the
LED chip and extended at the other end over the outside of the
package body, thereby being contacting the other pattern line of
the board..].
.[.6. The high power LED package according to claim 1, wherein the
heat transfer section of the first sheet metal member has a
T-shaped cross section and extends downwardly..].
.[.7. The high power LED package according to claim 1, wherein the
heat transfer section of the first sheet metal member is formed
such that its lower end facing the second sheet metal member is cut
at a slant away from the second sheet metal member and the cut
portion of the heat transfer section is covered with the package
body..].
.[.8. The high power LED package according to claim 1, wherein the
second sheet metal member has a structure symmetrical to the first
sheet metal member..].
.[.9. The high power LED package according to claim 8, wherein the
first and second sheet metal members are connected at their lower
portion with pattern lines of the board..].
.[.10. The high power LED package according to claim 1, further
comprising a high reflectivity reflective layer coated on the inner
surface of the recess..].
.[.11. The high power LED package according to claim 1, further
comprising a lens assembled onto the upper surface of the package
body, and wherein the package body has a step at its upper edge so
as to be engaged with the lower portion of the lens..].
12. A high power Light Emitting Diode (LED) package .[.mounted on a
board, which includes a metal plate of a heat sink, an insulating
layer on the metal plate and a conductive pattern printed with
plural pattern lines on the insulating layer, the high power LED
package.]. comprising: an LED chip; a package body integrally
formed with resin to have a recess for receiving the LED chip; a
half T-shaped first sheet metal member electrically connected with
the LED chip while supporting the LED chip at its upper partial
portion in the recess, the first sheet metal member surrounded by
the package body and extending to the side face of the package
body, wherein the first sheet metal member has an upper section
electrically connected at one end with the LED chip and a lower
section overlapped on the lower portion of the upper section, the
bottom surface of the lower section being exposed through the
bottom face of the package body .[.to contact the board.].; a
second sheet metal member electrically connected with the LED chip
spaced apart from the first sheet metal member for a predetermined
gap, the second sheet metal member extending through the inside of
the package body to the side face of the package body .[.in a
direction opposite to the first sheet metal member.].; and a
transparent sealant sealingly filled up into the recess.
13. The high power LED package according to claim 12, wherein the
upper and lower sections of the first sheet metal member are bonded
together with conductive epoxy with high thermal and electric
conductivities.
14. The high power LED package according to claim 12, wherein the
first sheet metal member is folded up at the other end that is
exposed through the package body side so that the upper and lower
sections thereof are overlapped vertically on each other.
15. The high power LED package according to claim 12, wherein the
other ends of the first and second sheet metal members are
protruded from a sidewall of the package body.
16. The high power LED package according to claim 12, wherein the
second sheet metal member has a structure symmetrical to that of
the first sheet metal member.
17. The high power LED package according to claim 12, wherein the
first and second sheet metal members are protruded at their lower
ends downwardly from the bottom face of the package body.
18. The high power LED package according to claim 12, further
comprising a high reflectivity reflective layer coated on the inner
surface of the recess.
19. The high power LED package according to claim 12, further
comprising a lens assembled onto the upper surface of the package
body, and wherein the package body has a step at its upper edge so
as to be engaged with the lower portion of the lens.
20. A high power Light Emitting Diode (LED) package .[.mounted on a
board, which includes a metal plate of a heat sink, an insulating
layer on the metal plate and a conductive pattern printed with
plural pattern lines on the insulating layer, the high power LED
package.]. comprising: an LED chip; a package body integrally
formed with resin to have a recess for receiving the LED chip; a
first sheet metal member electrically connected with the LED chip
.[.while.]..Iadd., the first sheet metal member having an upper
partial portion .Iaddend.supporting the LED chip .[.at its upper
partial portion.]. in the recess, the first sheet metal member
.Iadd.being .Iaddend.surrounded by the package body and extending
to .[.the.]. .Iadd.a .Iaddend.side face of the package body,
.[.with a partial bottom surface of.]. the first sheet metal member
.Iadd.having a bent section .Iaddend.bent downward .[.to be
exposed.]. .Iadd.within the package body to expose a partial bottom
surface of the first sheet metal member .Iaddend.through .[.the.].
.Iadd.a .Iaddend.bottom face of the package body .[.and to contact
the conductive pattern of the board.].; a second sheet metal member
electrically connected with the LED chip .Iadd.and .Iaddend.spaced
apart from the first sheet metal member .[.for.]. .Iadd.by
.Iaddend.a predetermined gap, the second sheet metal member
extending through the inside of the package body to the side face
of the package body .[.in a direction opposite to the first sheet
metal member.].; and a transparent sealant sealingly filled .[.up
into.]. .Iadd.in .Iaddend.the recess.
21. The high power LED package according to claim 20, wherein the
bent .[.shape of the first sheet metal member is formed by etching
or press working.]. .Iadd.section is an etched or pressed portion
.Iaddend.of a source sheet metal .Iadd.defining the first sheet
metal member.Iaddend..
22. The high power LED package according to claim 20, wherein a
lower portion of the first sheet metal member is exposed at a
middle portion in length through the bottom face of the package
body.
23. The high power LED package according to claim 22, wherein the
exposed lower portion of the first sheet metal member is extended
out of the bottom face of the package body.
24. The high power LED package according to claim 20, wherein the
first sheet metal member is exposed at .[.the.]. .Iadd.a
.Iaddend.lower portion adjacent to one end thereof through the
bottom face of the package body .[.to contact the board.]..
25. The high power LED package according to claim 20, wherein the
other end of the first sheet metal member is protruded out of a
sidewall of the package body.
26. The high power LED package according to claim 20, wherein the
bottom surface of the first sheet metal member .[.adjacent to one
side thereof is cut at a.]. .Iadd.has a cut portion .Iaddend.slant
away from the second sheet metal member, and the cut portion .[.of
the heat transfer section.]. is covered with the package body.
27. The high power LED package according to claim 20, wherein the
second sheet metal member has a structure symmetrical to that of
the first sheet metal member.
28. The high power LED package according to claim 20, further
comprising a high reflectivity reflective layer coated on the inner
surface of the recess.
29. The high power LED package according to claim 20, further
comprising a lens assembled onto the upper surface of the package
body, and wherein the package body has a step at its upper edge so
as to be engaged with the lower portion of the lens.
.Iadd.30. The high power LED package according to claim 20, wherein
the first sheet metal member includes a first section which
supports at its upper surface the LED chip in the package body, and
is exposed at its lower surface to an outside of the package body
through the bottom face of the package body, and a second section
which is formed stepwise upwards from the lower surface of the
first section..Iaddend.
.Iadd.31. The high power LED package according to claim 30, wherein
the second section of the first sheet metal member extends to the
outside between a lower portion and an upper portion of the package
body..Iaddend.
.Iadd.32. The high power LED package according to claim 30, wherein
the second sheet metal member includes a first section which is
spaced apart from the first section of the first sheet metal member
by the predetermined gap, and is exposed at its lower surface to
the outside through the bottom face of the package body, and a
second section which is formed stepwise upwards from the lower
surface of the first section of the second sheet metal
member..Iaddend.
.Iadd.33. The high power LED package according to claim 32, wherein
the second section of the second sheet metal member extends to the
outside between the lower portion and the upper portion of the
package body..Iaddend.
Description
.Iadd.Notice: More than one reissue application has been filed for
the reissue of U.S. Pat. No. 7,208,772. The reissue applications
are the present application, Ser. No. 13/294,405, and Ser. No.
13/330,239. The present application is a reissue application of
U.S. Pat. No. 7,208,772. Each of Ser. No. 13/294,405 and Ser. No.
13/330,239 is a Continuation Reissue Application of the present
application..Iaddend.
CLAIM OF PRIORITY
This application claims the benefit of Korean Patent Application
Nos. 2004-69730 filed on Sep. 1, 2004 and 2005-37421 filed on May
4, 2005, in the Korean Intellectual Property Office, the
disclosures of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a Light Emitting Diode (LED)
package, and more particularly, a high power LED package designed
to raise thermal radiation efficiency with a simplified structure
in order to reduce the size and thickness thereof.
2. Description of the Related Art
LEDs are one type of semiconductors, and generate various colors of
light when applied with voltage. When each LED generates light, its
color is generally determined by chemical ingredients of the LED.
Demand for the LEDs is continuously growing since the LEDs have
various merits such as long lifetime, low drive voltage, excellent
initial drive properties, high vibration resistance and high
tolerance with respect to repeated power switching compared to
lighting devices using filaments.
However, the LEDs also fail to convert electricity into light for
100%, thereby creating a considerable amount of heat. As a
consequence, the LEDs adopt metal lead frames to radiate heat to
the outside because internal components of the LEDs become stressed
owing to their thermal expansion coefficient difference if heat is
not properly dissipated.
In particular, some LEDs such as high power LEDs are recently
adopted in illumination systems and backlight units for large-sized
Liquid Crystal Displays (LCDs). Such high power LEDs are required
to have superior thermal radiation performance because these
systems or units require larger power.
FIG. 1 is a perspective sectional view of a conventional high power
LED package. Referring to FIG. 1, the LED package 1 includes an LED
chip 2 made of for example InGaN semiconductor, a metal slug 3 for
seating the LED chip 2 thereon while functioning as heat guide
means, a housing 4 for containing the metal slug 3, a silicone
encapsulant 5 for sealing the LED chip 2 and the top of the metal
slug 3, a plastic lens 6 for covering the silicon encapsulant 5,
and a pair of wires 7 (only one is shown) for supplying voltage to
the LED chip 2. In the meantime, the wires 7 are electrically
connected with terminals 8. The LED chip 2 is connected to a
submount by means of solders, and the submount seats the LED chip 2
on the metal slug 3.
Referring to FIG. 2, the LED package 1 of FIG. 1 is mounted on a
board 10 of a heat sink, and a thermal conductive pad 9 such as
solder is interposed between the metal slug 3 of the LED package 1
and the board 10 to facilitate the heat conduction between
them.
The LED package 1 and its mounting structure on the board 10 as
shown in FIGS. 1 and 2 are focused on thermal radiation to
efficiently radiate heat to the outside. That is, the LED package 1
is so designed that the metal slug 3 as a heat sink is mounted
directly or via the thermal conductive pad 9 on the board 10 in
order to absorb heat generated from the LED chip 2 and radiate heat
to the outside. Then, a major quantity of heat from the LED chip 2
flows through the metal slug 3 to the board 10 and only a minor
quantity of heat is radiated to the air through the surface of the
LED package 1 including the housing 4 and the lens 6.
Thanks to these reasons, LED packages of the above structure are
widely adopted in the LED field.
However, the above conventional thermal radiation structure of the
LED package has a bulky size thereby to obstruct the
miniaturization of an illumination system. This structure is also
complicated obstructing the automation of LED package production as
well as requiring a large number of components to be assembled
together thereby to burden manufacture cost.
SUMMARY OF THE INVENTION
The present invention has been made to solve the foregoing problems
of the prior art and it is therefore an object of the present
invention to provide a high power Light Emitting Diode (LED)
package in which radiating means conducting heat generated from LED
chip to a metal plate of a board is made into a sheet metal member,
thereby raising thermal radiation efficiency while reducing the
size and thickness thereof It is another object of the invention to
provide a high power LED package which secures effective radiating
means and in which a package body thereof is injection-molded with
resin, thereby simplifying a construction thereof and facilitating
its manufacture as well.
It is still another object of the invention to provide a high power
LED package in which a sheet metal member serving as both radiating
means and a terminal is fixedly surrounded with a resinous package
body, thereby obtaining a thinner and solid construction
thereof.
According to an aspect of the invention for realizing the object,
there is provided a high power Light Emitting Diode (LED) package
mounted on a board, which includes a metal plate of a heat sink, an
insulating layer on the metal plate and a conductive pattern
printed with plural pattern lines on the insulating layer, the high
power LED package comprising: an LED chip; a package body
integrally formed with resin to have a recess for receiving the LED
chip; a first sheet metal member electrically connected with the
LED chip while supporting the LED chip at its upper partial portion
in the recess, the first sheet metal member surrounded by the
package body and extending to the side face of the package body,
the first sheet metal member having a heat transfer section for
transferring heat generated from the LED chip to the metal plate of
the board and extending downward from the inside of the package
body so that a lower end thereof is exposed at a bottom face of the
package body thus to contact the board; a second sheet metal member
electrically connected with the LED chip spaced apart from the
first sheet metal member for a predetermined gap, the second sheet
metal member extending through the inside of the package body to
the side face of the package body in a direction opposite to the
first sheet metal member; and a transparent sealant sealingly
filled up into the recess.
Preferably, the heat transfer section of the first sheet metal
member is protruded downward from the bottom face of the package
body.
Preferably, the first and second sheet metal members each have at
least one hole, and the package body has a plurality of connecting
posts that are integrally formed and connected with the upper and
lower portions of the package body through the holes.
Preferably, the first sheet metal member is contacted with one
electrode of the LED chip, and further has an external terminal
integrally formed therewith to extend over the outside of the
package body thereby contacting one pattern line of the board, and
wherein the second sheet metal member is connected at one end of
the recess-side with the other electrode of the LED chip and
extended at the other end of the recess-side out of the package
body, thereby contacting the other pattern line of the board.
Preferably, the second sheet metal member is divided into a pair of
first and second terminals insulated from each other, in which the
first terminal is connected at one end with one electrode of the
LED chip and extended at the other end out of the package body,
thereby contacting one pattern line of the board, and wherein the
second terminal is connected at one end with the other electrode of
the LED chip and extended at the other end over the outside of the
package body, thereby being contacting the other pattern line of
the board.
Preferably, the heat transfer section of the first sheet metal
member has a T-shaped cross section and extends downwardly.
Alternatively, the heat transfer section of the first sheet metal
member is formed such that its lower end facing the second sheet
metal member is cut at a slant away from the second sheet metal
member and the cut portion of the heat transfer section is covered
with the package body.
According to another aspect of the invention for realizing the
object, there is provided a high power Light Emitting Diode (LED)
package mounted on a board, which includes a metal plate of a heat
sink, an insulating layer on the metal plate and a conductive
pattern printed with plural pattern lines on the insulating layer,
the high power LED package comprising: an LED chip; a package body
integrally formed with resin to have a recess for receiving the LED
chip; a half T-shaped first sheet metal member electrically
connected with the LED chip while supporting the LED chip at its
upper partial portion in the recess, the first sheet metal member
surrounded by the package body and extending to the side face of
the package body, wherein the first sheet metal member has an upper
section electrically connected at one end with the LED chip and a
lower section overlapped on the lower portion of the upper section,
the bottom surface of the lower section being exposed through the
bottom face of the package body to contact the board; a second
sheet metal member electrically connected with the LED chip spaced
apart from the first sheet metal member for a predetermined gap,
the second sheet metal member extending through the inside of the
package body to the side face of the package body in a direction
opposite to the first sheet metal member; and a transparent sealant
sealingly filled up into the recess.
Preferably, the upper and lower sections of the first sheet metal
member are bonded together with conductive epoxy with high thermal
and electric conductivities.
Preferably, wherein the first sheet metal member is folded up at
the other end that is exposed through the package body side so that
the upper and lower sections thereof are overlapped vertically on
each other.
Preferably, the other ends of the first and second sheet metal
members are protruded from a sidewall of the package body.
Preferably, the second sheet metal member has a structure
symmetrical to that of the first sheet metal member.
Preferably, the first and second sheet metal members are protruded
at their lower ends downwardly from the bottom face of the package
body.
According to still another aspect of the invention for realizing
the object, there is provided a high power Light Emitting Diode
(LED) package mounted on a board, which includes a metal plate of a
heat sink, an insulating layer on the metal plate and a conductive
pattern printed with plural pattern lines on the insulating layer,
the high power LED package comprising: an LED chip; a package body
integrally formed with resin to have a recess for receiving the LED
chip; a first sheet metal member electrically connected with the
LED chip while supporting the LED chip at its upper partial portion
in the recess, the first sheet metal member surrounded by the
package body and extending to the side face of the package body,
with a partial bottom surface of the first sheet metal member bent
downward to be exposed through the bottom face of the package body
and to contact the conductive pattern of the board; a second sheet
metal member electrically connected with the LED chip spaced apart
from the first sheet metal member for a predetermined gap, the
second sheet metal member extending through the inside of the
package body to the side face of the package body in a direction
opposite to the first sheet metal member; and a transparent sealant
sealingly filled up into the recess.
Preferably, the bent shape of the first sheet metal member is
formed by etching or press working of a source sheet metal.
Preferably, a lower portion of the first sheet metal member is
exposed at a middle portion in length through the bottom face of
the package body. At this time, the exposed lower portion of the
first sheet metal member is extended out of the bottom face of the
package body.
Preferably, the other end of the first sheet metal member is
protruded out of a sidewall of the package body.
Meanwhile, preferably, the bottom surface of the first sheet metal
member adjacent to one side thereof is cut at a slant away from the
second sheet metal member, and the cut portion of the heat transfer
section is covered with the package body.
In addition, preferably, the second sheet metal member has a
structure symmetrical to that of the first sheet metal member.
The LED packages above may further comprise a high reflectivity
reflective layer coated on the inner surface of the recess.
Preferably, any one of the LED packages above may further comprise
a lens assembled onto the upper surface of the package body, and
wherein the package body has a step at its upper edge so as to be
engaged with the lower portion of the lens.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional perspective view illustrating a conventional
high power LED package;
FIG. 2 is a sectional view illustrating the high power LED package
of FIG. 1 mounted on a board;
FIG. 3 is a plan view illustrating a high power LED package
according to a first embodiment of the invention;
FIG. 4 is a sectional view taken along a line A-A of FIG. 3;
FIG. 5 is a plan view illustrating the high power LED package of
FIG. 3 with the upper portion of the package body removed;
FIG. 6 is a bottom view of FIG. 3;
FIG. 7 is a sectional view illustrating the high power LED package
according to the first embodiment of the present invention with a
lens attached thereto;
FIG. 8 is a sectional view illustrating another form of the high
power LED package as shown in FIG. 4;
FIG. 9 is a sectional view corresponding to FIG. 4, illustrating a
high power LED package according to a second embodiment of the
present invention;
FIG. 10 is a sectional view illustrating a state in which the LED
package of FIG. 9 is mounted on a board;
FIG. 11 is a sectional view illustrating a modification to the high
power LED package of FIG. 9;
FIG. 12 is a plan view illustrating a high power LED package
according to a third embodiment of the present invention;
FIG. 13 is a sectional view taken along a line A-B of FIG. 12.
FIG. 14 is a plan view illustrating the high power LED package of
FIG. 12 with the upper portion of the package body removed;
FIG. 15 is a sectional view illustrating a high power LED package
according to a fourth embodiment of the present invention;
FIG. 16 is a sectional view illustrating a high power LED package
according to a fifth embodiment of the present invention;
FIG. 17 is a sectional view illustrating a modification to the high
power LED package of FIG. 16.
FIG. 18 is a sectional view illustrating another modification to
the high power LED package of FIG. 16.
FIG. 19 is a sectional view illustrating a high power LED package
according to a sixth embodiment of the present invention;
FIGS. 20 through 23 are stepwise sectional views illustrating a
manufacturing process of a high power LED package according to the
present invention;
FIG. 24 is a plan view illustrating a high power LED package
according to a seventh embodiment of the present invention;
FIG. 25 is a sectional view taken along a line C-C of the LED
package of FIG. 24;
FIG. 26 is a bottom view of the LED package of FIG. 24;
FIG. 27 is a sectional view illustrating a modification to the high
power LED package according to the seventh embodiment of the
present invention;
FIG. 28 is a sectional view illustrating a high power LED package
according to an eighth embodiment of the present invention;
FIG. 29 is a sectional view illustrating a high power LED package
according to a ninth embodiment of the present invention; and
FIG. 30 is a sectional view illustrating a modification to the high
power LED package of FIG. 29.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Hereinafter the above and other objects, features and other
advantages of the present invention will be more clearly understood
from the following detailed description taken in conjunction with
the accompanying drawings.
First, a high power Light Emitted Diode (LED) package according to
a first embodiment of the present invention will now be described
with reference to FIGS. 3 through 6. FIG. 3 is a plan view
illustrating a high power LED package according to a first
embodiment of the invention, FIG. 4 is a sectional view taken along
a line A-A of FIG. 3, FIG. 5 is a plan view illustrating the high
power LED package of FIG. 3 with the upper portion of the package
body removed, and FIG. 6 is a bottom view of FIG. 3.
As shown in FIGS. 3 through 6, the high power LED package 100 of
the present invention is used as mounted on a board (see FIG. 10)
having a metal plate of a heat sink, an insulating layer on the
metal plate and a conductive pattern printed with plural pattern
lines on the insulating layer. The high power LED package includes
an LED chip 112 for emitting light when applied with electric
current, a package body 102 integrally formed with resin and having
a recess 108 to receive the LED chip 112, a first sheet metal
member 114 positioned in the package body 102, functioning as a
terminal and radiating means while supporting the LED chip 112, a
second sheet metal member 116 functioning as a terminal, and a
sealant 110 for sealingly filling up the recess 108.
First, the package body 102 is formed by injection molding of
resin, such that the upper surface of the upper portion 102A
thereof is sunk toward its center portion, forming the recess 108.
Herein, the inner wall of the recess 108 is preferably formed to
have a certain slant. A lower portion 102B of the package body
receives the first and second sheet metal members 114 and 116
together with the upper portion 102A of the package body.
Herein, as shown in FIGS. 4 and 5, the upper and lower portions
102A and 102B of the package body are connected with each other at
their both longitudinal edges as well as by a plurality of posts
104 extending vertically through holes formed to the first and
second sheet metal members 114 and 116. Thus, the posts serve to
strengthen a connection between the upper and lower portions 102A
and 102B of the package body. Meanwhile, although illustrated as a
circular shape, the sectional end shape of the post may become oval
or rectangular. In this case, because a cross-sectional area
thereof becomes larger at the same width position relative to the
circular shape, the connection between the upper and lower portions
102A and 102B of the package body may be further strengthened.
A first section 114a of the first sheet metal member 114 supports
at its upper portion the LED chip 112 in the recess 108, and
extends downwardly through the inside of the package body 102 thus
to be exposed at its lower portion through the bottom surface of
the lower portion 102B of the package body 102 to the outside
thereof. As a result, heat generated at the LED chip 112 can be
transferred smoothly through the first section 114a of the first
sheet metal member 114 to the metal plate of the board. That is, it
can be understood that in the present invention, the first section
114a of the first sheet metal member 114 may function as radiating
means. Herein, since the first section 114a of the first sheet
metal member 114 as radiating means, is a part of the sheet metal
member, a thickness thereof is seriously reduced relative to the
metal slug 3 (see FIGS. 1 and 2) of the prior art. It can be
accordingly seen that a heat transfer path from the LED chip 112 to
the metal plate below the first section 114a is greatly reduced,
thereby increasing thermal radiation efficiency considerably.
A second section 114b of the first sheet metal member 114 is a
portion integrally extended from the first section 114a toward the
side of the package body 102, whose thickness is reduced relative
to the first section 114a such that its upper surface extends on
the same plane as the upper portion of the first section 114a, and
its bottom face is stepped upwards from the lower portion of the
first section 114a. Thus, differently from the first section 114a,
the second section 114b extends laterally toward the side of the
package body 102 without being exposed at its bottom face to the
outside, thereby being connected with a third section 114a outside
of the package body 102. The third section 114c extends integrally
with and in the same thickness as the second section 114b, and has
at its middle portion a bent portion twice-bent so as to facilitate
the connection with one pattern line of the conductive pattern of
the board. The third section 114c functions as an external terminal
in the first sheet metal member 114.
The second sheet metal member 116 extends in an opposite direction
and spaced apart for a predetermined gap from the first sheet metal
member 114. The second sheet metal member 116 extends laterally
with a certain thickness from the inside of the package body 102
toward outside of the package body 102, and a portion thereof
outside the package body has a bent portion twice-bent so as to
facilitate the connection with the other pattern line of the
conductive pattern of the board. A cross-sectional shape of these
sheet metal members 114 and 116 may be formed by, for example,
cutting and punching a source sheet metal plate, and selectively
reducing thickness through etching and the like.
Herein, the first and second sheet metal members 114 and 116 are
connected with the electrodes, respectively, of the LED chip 112 by
means of a pair of wires 118. As a result, the LED chip 112 can be
supplied with electric power from a power supply through the wires
118, the first and second sheet metal members 114 and 116, and the
conductive pattern of the board.
A reflective layer 106 composed of a high reflectivity film is
formed at an inner wall of the recess 108 in order to effectively
guide light emitted from the LED chip 112 upwards. The reflective
layer 106 may be formed by coating Ag, Pt, Al or alloy thereof onto
the inner wall of the recess 108 with for example, an electroless
plating or a deposition and the like. Alternatively, the recess 108
is precisely machined at its inner wall so that a certain amount of
reflectivity may be achieved although it is not perfect.
Furthermore, a glass layer may be formed on the inner wall of the
recess 108 so as to intensify a function of reflecting mirror using
a density difference from resin of the package body below the glass
layer.
FIG. 7 is a sectional view illustrating the high power LED package
100 according to the first embodiment of the present invention with
a lens attached thereto. In FIG. 7, the lens 120 is attached to the
upper surface of the package body 102 to protect a sealant 110 and
the LED chip 112 contained therein. Herein, the lens 120 is
generally transferred and formed onto the package body 102, or
otherwise fabricated separately and then bonded to the package body
102 with proper means such as an adhesive and the like.
Structured like this, the first and second sheet metal members 114
and 116 with a simple construction serve as radiating means and
terminals, and the integrated package body 102 injection-molded
with resin bonds these members strongly, thereby greatly improving
thermal radiation efficiency as well as securing excellent
robustness while reducing their dimension significantly.
FIG. 8 is a sectional view illustrating another form of the high
power LED package as shown in FIG. 4.
In the LED package 100 in FIG. 8, the first sheet metal member 114
adjacent to the second sheet metal member 116 has at a part thereof
a step 114d, thus to form a T-shaped overall cross section. This
step 114d has the following function.
The LED chip 112 may be mal-functioned by moisture, foreign
substances and so forth, thus it is important to protect the LED
chip from such condition. In addition, because of high temperature
accompanied by an operation thereof, repetitive ON/OFF operations
or a long time ON operation cause heterogeneous substances such as
the metallic sheet metal member and the plastic package body to
gradually separate from each other at an interface thereby forming
a passageway for the moisture or foreign substances and the like.
Thus, in order to improve reliability of products, it is needed to
prevent such problem. Preferable one method to do this is to
lengthen a way from the outside of the package to the LED chip
112.
In addition, such T shape of the first sheet metal member 114
functions very well to fix the package body 102, like a reinforced
concrete structure. That is, it makes the connection between the
sheet metal member and the package body 102 more facilitated and
strengthened. Accordingly, the finished LED package 100 can endure
well against shocks and external force applied thereto.
FIG. 9 is a sectional view corresponding to FIG. 4, illustrating a
high power LED package according to a second embodiment of the
present invention, and FIG. 10 is a sectional view illustrating a
state in which the LED package of FIG. 9 is mounted on the
board.
Referring first to FIG. 9, the high power LED package 200 of the
present embodiment has a construction identical to that of the LED
package 100 of the first embodiment, except that a first section
214a of a first sheet metal member 214 is protruded outside from
the bottom surface of a package body 202 for a predetermined
length. Thus, constitutional elements the same as or similar to
those of the LED package 100 are designated with corresponding
reference numerals, increased by 100, and detailed description
thereof will be omitted.
When the first section 214a of the first sheet metal member of
radiating means are protruded from the bottom surface of the
package body 202 as such, it is advantageous when mounting the LED
package 200 on the board 10 as illustrated in FIG. 10. In detail,
the board 10 on which the LED package 200 is mounted includes a
metal plate 12 of a heat sink, an insulating layer 14 on the metal
plate 12, and a conductive pattern with plural lines 18 printed on
the insulating layer 14. When mounting the LED package 200 on the
board 10, the third section 214c of the first sheet metal member
and a distal end or an outer end of the second sheet metal member
functioning as a lead are bonded to the corresponding line 18 of
the board 10 by soldering and so forth. As a result, there is an
effect in that solder is interposed between the whole LED package
200 and the board 10, so that a distance between the first section
of the first sheet metal member and the corresponding portion of
the board may be increased. However, since the first section 214a
of the first sheet metal member of this embodiment is protruded
outside from the bottom surface of the package body 202 for a
predetermined length, it is not required to increase the thickness
of the solder that is attached between the first section and the
corresponding portion of the board. Therefore, it may be possible
to maintain a thin thickness in the solder, thereby securing
excellent heat transfer effect continuously. Furthermore, depending
on the protruded length, a contact between the first section of the
first sheet metal member and the corresponding portion of the board
can be maintained without forming the solder and the like
therebetween, thereby intensifying the effect.
FIG. 11 is a sectional view illustrating a modification to the high
power LED package of FIG. 9.
In the LED package 200 in FIG. 11, a part of the first sheet metal
member 214 adjacent to the second sheet metal member 216 is formed
with a step 214d, so that the first sheet metal member 214 has a
T-shaped overall cross-section. Such structure of the LED package
200 is obtained by combining the structure of FIG. 8 with that of
FIG. 9. Accordingly, this provides improved heat transfer effect
and intensified reliability of the package as well.
FIG. 12 is a plan view illustrating a high power LED package
according to a third embodiment of the present invention, FIG. 13
is a sectional view taken along a line B-B of FIG. 10, and FIG. 14
is a plan view illustrating the high power LED package of FIG. 12
with the upper portion of the package body removed.
Referring to FIGS. 12 through 14, the LED package 300 according to
the third embodiment is discriminated from the LED package 100
according to the first embodiment, in that a first sheet metal
member 314 consists of first and second sections 314a and 314b
without protruded beyond the side of a package body 302, and a
second sheet metal member 316 consists of first and second
terminals 316A and 316B. Thus, constitutional elements the same as
or similar to those of the LED package 100 are designated with
corresponding reference numerals, increased by 200, and detailed
description thereof will be omitted.
According to this embodiment, the first sheet metal member 314
functions as radiating means, the first and second terminals 316A
and 316B each serve to electrically connect the LED chip 312 to the
power supply through wires 318.
Meanwhile, in the high power LED package 300, the first section
314a of the first sheet metal member may be constructed such that
it is protruded outside from the bottom face of the package body
302 as shown in FIGS. 9 and 10.
FIG. 15 is a sectional view illustrating a high power LED package
according to a fourth embodiment of the present invention.
Referring to FIG. 15, the construction thereof is substantially
identical to the construction of FIG. 3, except that an LED chip
412 is bonded onto a submount 430 with a flip chip bonding method,
and supported on a first section 414a of a first sheet metal member
414. Thus, constitutional elements the same as or similar to those
of the LED package 100 are designated with corresponding reference
numerals, increased by 300, and detailed description thereof will
be omitted.
The submount 430 comprises a board made of silicon and the like,
and thus can properly buffer the LED chip 412 against a shock or
distortion of the first sheet metal member 414 and the like. At
this time, with the forming of the conductive pattern onto the
surface of the submount 430 and the electrical connecting to the
first and second sheet metal members 414 and 416 through the wires
418, the LED chip 412 bonded to that pattern with a flip chip
bonding method can be electrically connected with the power
supply.
Meanwhile, the submount 430 is formed in a size larger than the LED
chip 412 seated thereon, and has preferably high thermal
conductivity so as to effectively transfer heat generated from the
LED chip 412 to the first section 414a of the first sheet metal
member below the submount. Specifically, thermal conductivity may
be preferably 100 W/mK or more, more preferably, 200 W/mK or more.
For reference, it is needed that the sheet metal member has thermal
conductivity of about 300 W/mK.
In the meantime, the present embodiment may employ the T-shaped
first sheet metal member like in FIG. 8, the protruded first
section of the first sheet metal member like in FIG. 9, the
protruded T-shaped first sheet metal member like in FIG. 11, and
radiating means and the structure of first and second terminals
like in FIG. 12.
FIG. 16 is a sectional view illustrating a high power LED package
according to a fifth embodiment of the present invention. Referring
to FIG. 16, the high power LED package 500 of the present
embodiment is different from the LED package 100 of the first
embodiment, in that the first sections 514a and 516a as radiating
means each are formed at both of the first and second sheet metal
members 514 and 516, and the LED chip 512 is connected to these
first and second sheet metal members 514 and 516 with the flip chip
method. Thus, constitutional elements the same as or similar to
those of the LED package 100 are designated with corresponding
reference numerals, increased by 400, and detailed description
thereof will be omitted.
Structured as such, there is an advantage in that the first
sections 514a and 516a as radiating means has an enlarged area thus
to transfer heat of the LED chip 512 to the board (not shown) below
the construction more effectively.
However, since the both first sections 514a and 516a cannot be
electrically connected to the metal plate of the board at the same
time, any one of the first sections 514a or 516a should be only
thermally connected to the metal plate, but electrically insulated
from the same.
Of course, the present embodiment may employ the T-shaped first
sheet metal member like in FIG. 8, the protruded first section of
the first sheet metal member like in FIG. 9, the protruded T-shaped
first sheet metal member like in FIG. 11, and radiating means and
the structure of first and second terminals like in FIG. 12.
FIG. 17 is a sectional view illustrating a modification to the high
power LED package of FIG. 15. Referring to FIG. 17, the high power
LED package 500-1 of this embodiment is different from the
construction of FIG. 16, in that the first and second sheet metal
members 514 and 516 of FIG. 16 are replaced with the generally
T-shaped first and second sheet metal members 514A and 516A. Of
course, the first and second sheet metal members 514A and 516A may
have an inverted L shape or a half T shape like in FIG. 16.
The first sheet metal member 514A may be formed into a T shape via
for example etching, by which the lower portion reduced in diameter
is exposed from the bottom face 502B of the package body, to form
an I/O terminal directly contacting the conductive lines 18 of the
board 10 as shown in FIG. 10. Herein, the lower portions of the
T-shaped sheet metal members 514A and 516A may be extended from the
bottom face 502B of the package body, thereby facilitating the
electrical connection with the conductive lines 18.
Meanwhile, the construction of this embodiment may employ the
construction of FIG. 15. That is, the LED chip 512 may be
electrically connected with the first and second sheet metal
members 514A and 516A through the wires 418.
FIG. 18 is a sectional view illustrating another modification to
the high power LED package of FIG. 15.
As shown in FIG. 18, by protruding the first sheet metal member
514A downwardly from the package body 502, it is possible to
improve reliability and further increase heat transfer effect. In
addition, if necessary, it may be constructed to protrude the
second sheet metal member 516A like as such.
FIG. 19 is a sectional view illustrating a high power LED package
according to a sixth embodiment of the present invention. Referring
to FIG. 19, the LED package 600 of the present embodiment has the
construction generally identical to that of the LED package 100 of
the first embodiment, except that a step 624 for mounting a lens is
formed at the upper portion of the package body 602.
By forming such step 624 like this and a flange 622 conforming in
shape with the step at the lower portion of the lens 620, it
becomes easy to facilitate coupling since the flange 622 and the
step 624 are engaged with each other when mounting the lens 620 to
the package body 602. This is the case where the lens 620 is
separately manufactured and assembled to the package body. However,
even in the case where the lens 620 is formed with a transfer
forming, the lens forming process is easy and the engaging force
therebetween is also intensified.
The present embodiment may also employ the T-shaped first sheet
metal member like in FIG. 8, the protruded first section of the
first sheet metal member like in FIG. 9, the protruded T-shaped
first sheet metal member like in FIG. 11, and radiating means and
the structure of first and second terminals like in FIG. 12.
Hereinafter, a manufacturing process of the LED package according
to the present invention will be described with reference to the
sectional process views of FIGS. 20 through 23. For convenience's
sake, as for the LED package adapted to thus process, that of the
first embodiment is used.
First, a step is conducted to dispose a frame where the first and
second sheet metal members 114 and 116 are integrally coupled, as
shown in FIG. 20. As can be seen from the drawing, holes H are
formed vertically through these sheet metal members 114 and
116.
Then, as shown in FIG. 21, a step is conducted to form the package
body 102 at a position predetermined by the injection molding.
Herein, resin forming the package body 102 is poured into the holes
H and cured to form the posts 104 (see FIGS. 4 and 5) as described
before.
Next, as shown in FIG. 22, a step is conducted to form the
reflective layer 106 onto the inner wall of the recess 108 of the
package body 102, to seat the LED chip 112 on the first section of
the first sheet metal member 114, and to electrically connect the
first and second sheet metal members 114 and 116 with the power
supply through the wires 118.
Then, as shown in FIG. 23, a step is conducted to fill up the
recess 108 with the sealant 110 to seal the LED chip 112 and the
like therein. Next, a step is conducted to cut the first and second
sheet metal members 114 and 116 in frame shape to obtain the LED
package 100 like in FIG. 4.
For reference, in manufacturing the LED package 300 like in FIG.
13, two one-dot chain lines L1 and L2 are cut together.
Hereinafter, an LED package according to a seventh embodiment of
the present invention will be described with reference to FIGS. 24
through 26. FIG. 24 is a plan view illustrating the high power LED
package according to the seventh embodiment of the present
invention, FIG. 25 is a sectional view taken along a line C-C of
the LED package of FIG. 24, and FIG. 26 is a bottom view of the LED
package of FIG. 24.
The high power LED package 700 of the present embodiment is used
mounted on a board (see FIG. 10) having a metal plate of a heat
sink, an insulating layer on the metal plate and a conductive
pattern printed with plural pattern lines on the insulating
layer.
As shown in FIGS. 24 through 26, the high power LED package 700
includes an LED chip 712 for emitting light when applied with
electric current, a package body 702 integrally formed with resin
to have a recess 708 for receiving the LED chip 712, first and
second sheet metal members 714 and 716 positioned in the package
body 702, functioning as a terminal and radiating means while
supporting the LED chip 712, and a sealant 710 for sealingly
filling up the recess 708.
First, the package body 702 is formed by injection molding of resin
such that the upper surface of the upper portion 702A thereof is
sunk toward its center portion, forming the recess 708. Herein, the
inner wall of the recess 708 is preferably formed to have a certain
slant. A lower portion 702B of the package body receives the first
and second sheet metal members 714 and 716 together with the upper
portion 702A of the package body. Herein, as shown in FIG. 22, the
upper and lower portions 702A and 702B of the package body are
connected with each other at their both longitudinal edges to
stably fix the first and second sheet metal members 714 and 716
therebetween. In addition, although not illustrated, by forming a
hole to each of the first sections 714A and 716A and connecting the
upper and lower portions 702A and 702B of the package body together
through the holes, it is possible to fix the first and second sheet
metal members 714 and 716 more stably.
The first sheet metal member 714 consists of first and second
sections 714A and 714B overlapped vertically and combined in a half
T shape, the first and second sections 714A and 714B having a width
smaller than the package body 702. The first and second sections
714A and 714B are attached to each other with conductive epoxy and
the like having high thermal and electric conductivity, rendering
the current and heat transfer therebetween conducted smoothly. The
first section 714A supports at one end the LED chip 712 in the
recess 708 while being electrically connected thereto, and extends
at the other end over the sidewall of the package body 702. The
second section 714B is exposed at its bottom surface from the
bottom face of the lower portion 702B of the package body, and
extends at one end (positioned at right side in the drawing) over
the sidewall of the package body thus to form a protrusion together
with the other end of the first section 714A. Meanwhile, the second
section 714B is formed shorter than the first section 714A such
that generally half portion thereof adjacent to the LED chip 712 on
the first section 714A is completely surrounded and fixed by the
package body 702.
The second sheet metal member 716 has a mirror image shape to the
first sheet metal member 714, and consists of the first and second
sections 716A and 716B, whose width is formed smaller than the
package body 702. The first and second sections 716A and 716B are
attached to each other with conductive epoxy and the like having
high thermal and electric conductivity, rendering the current and
heat transfer therebetween conducted smoothly. The first section
716A is at one end positioned adjacent to the LED chip 712 in the
recess 708 as to be electrically connected thereto, and extends at
the other end over the sidewall of the package body 702. The second
section 716B is exposed at its bottom surface from the bottom face
of the lower portion 702B of the package body, and extends at one
end (positioned at left side in the drawing) over the sidewall of
the package body thus to form a protrusion together with the other
end of the first section 716A. Meanwhile, the second section 716B
is formed shorter than the first section 716A such that generally
half portion thereof adjacent to the LED chip 712 on the first
section 716A is completely surrounded and fixed by the package body
702.
As a result, heat generated at the LED chip 712 can be transferred
smoothly through the first and second sections 714A and 714B of the
first sheet metal member 714 to the metal plate of the board. That
is, it can be understood that in the present invention, the first
sheet metal member 714 may function as radiating means. Herein,
since the first section 714A of the first sheet metal member 714,
radiating means, is a part of the sheet metal member, a thickness
thereof is seriously reduced relative to the metal slug 3 (see
FIGS. 1 and 2) of the prior art. It can be accordingly seen that a
heat transfer path from the LED chip 712 to the metal plate below
the first section is greatly reduced, thereby increasing thermal
radiation efficiency considerably. In addition, since the second
sheet metal member 716 also functions as radiating means as well,
thermal radiation efficiency may be further increased.
Furthermore, the first sheet metal member 714 has the half T shape,
so that a path of foreign substances, moisture and the like
intruded from the lower portion 702B of the package body into the
package body becomes longer to improve reliability of the LED
package 700.
The other elements of this embodiment are substantially identical
to those of the LED package 100 of the first embodiment, and thus
the detailed description thereof will be omitted.
FIG. 27 is a sectional view illustrating a modification to the high
power LED package according to the seventh embodiment of the
present invention. An LED package 700-1 of this embodiment has
substantially the same construction as the LED package 700 of the
seventh embodiment, except that a first sheet metal member 714-1
consists of first and second sections 714A and 714B folded up on
each other through bending at a bent 720A, and a second sheet metal
member 716-1 consists of first and second sections 716A and 716B
folded up on each other through bending at a bent 720B. Thus, the
detailed description for the other elements will be omitted.
FIG. 28 is a sectional view illustrating a high power LED package
according to an eighth embodiment of the present invention.
Referring to FIG. 8, the high power LED package 800 of the eighth
embodiment is substantially identical to the construction of LED
package 700 of the seventh embodiment, except for the first and
second sheet metal members 814 and 816.
That is, the first sheet metal member 814 is formed such that the
second section 814B thereof is bent downward to the first and third
sections 814A and 814C thereof, exposing itself through the bottom
face of the lower portion 802B of the package body, and the third
section 814C is exposed through the sidewall of the package body
802. Also, the second sheet metal member 816 is formed such that
the second section 816B thereof is bent downwardly to the first and
third sections 816A and 816C thereof, being exposed through the
bottom face of the lower portion 802B of the package body, and the
third section 816C is exposed through the sidewall of the package
body 802.
Such shape of the sheet metal members 814 and 816 can be obtained
by bending a certain portion of the source sheet metal plate, the
second sections 814B and 816B, by means of a press and the like. In
addition, on the contrary, such shape can be formed by selective
etching and the like of the source sheet metal plate.
As a result, heat generated at the LED chip 812 can be transferred
smoothly through the first and second section 814A and 814B of the
first sheet metal member 814 to the metal plate of the board. That
is, it can be understood that in the present invention, the first
sheet metal member 814 may function as radiating means. Herein,
since the first section 814A of the first sheet metal member 814 as
radiating means is a part of the sheet metal member, the thickness
thereof is seriously reduced relative to the metal slug 3 (see
FIGS. 1 and 2) of the prior art. It can be accordingly seen that a
heat transfer path from the LED chip 812 to the metal plate below
the first section is greatly reduced, thereby increasing thermal
radiation efficiency considerably. In addition, since the second
sheet metal member 816 also functions as radiating means as well,
thermal radiation efficiency may be further increased.
In addition, when exposing the terminals in downset manner from the
first and second sheet metal members 814 and 816, the bent sheet
metal members 814 and 816 operates like reinforced concrete
structure, rendering the connection with the package body 802 more
effective and intensified. Further, like the T shaped or half
T-shaped sheet metal member structure as mentioned before, a path
of foreign substances, moisture and the like intruded from the
bottom face of the lower portion 802B of the package body into the
body through a gap (that may be formed later) between the sheet
metal members 814 and 816 and the package resin becomes longer and
complicated to improve reliability of the LED package.
FIG. 29 is a sectional view illustrating a high power LED package
according to a ninth embodiment of the present invention. Referring
to FIG. 29, the high power LED package 900 according to the ninth
embodiment has the cross-sectional shape similar to the LED package
800 of the eighth embodiment in FIG. 28, but has the construction
of the first and second sheet metal members 914 and 916 deformed
from that of the eighth embodiment.
That is, the first sheet metal member 914 includes the first and
second sections 914A and 914B. The first section 914A supports at
its upper surface the LED chip 912 in the package body 902, and is
exposed at its lower surface outside via the lower portion 902B of
the package body. The second section 914B is formed stepped upwards
and extends to the outside between the lower portion 902B and the
upper portion 902A of the package body. Meanwhile, the second sheet
metal member 916 includes first and second sections 916A and 916B.
The first section 916A is spaced apart for a predetermined distance
from the first section 914A of the first sheet metal member 914,
and is exposed at its lower surface to the outside via the lower
portion 902B of the package body. The second section 916B is formed
stepped upwards from the first section 916A and extends to the
outside between the lower portion 902B and the upper portion 902A
of the package body to form a terminal.
Such a shape of the sheet metal members 914 and 916 can be obtained
by bending the sheet metal source plate between the first and
second sections 914A and 914B; 916A and 916B with a press and the
like, or selectively etching the same.
Constructed as such, heat generated from the LED chip 912 can be
smoothly transferred through the first section 914A of the first
sheet metal member 914 to the metal plate of the board like in FIG.
9, and a height of the whole package body 902 can be additionally
reduced as well.
Furthermore, because of the simplified construction relative to the
embodiments as mentioned before, it is possible to enable the
manufacturing process to be simplified and automated.
FIG. 30 is a sectional view illustrating a modification to the high
power LED package of FIG. 29.
Referring to FIG. 30, the lower portion at one end of the first
section 914A of the first sheet metal member 914 forms a slant
surface 914C cut slantly in a direction opposite to the first
section 916A of the second sheet metal member.
Similarly to for example the step 114d illustrated in FIG. 8, the
slant surface 914C makes the path of foreign substances and
moisture intruded into the LED chip 912 longer and complicated. In
addition, the slant surface 914C is covered with resin of the
package body 902, to improve the connection and air-tight feature
between the first sheet metal member 914 and the package body 902.
Further, instead of this slant surface 914C, the step 114d as in
FIG. 8 may be employed.
Furthermore, it may be also possible to form the slant surface 914C
or the step 114d in FIG. 8 to the second sheet metal member
916.
As described before, the high power LED package of the present
invention is constructed to form radiating means for transferring
heat generated from the LED chip to the metal plate of the board
into the sheet metal member, thereby improving thermal radiation
efficiency and reducing the size and thickness thereof.
In addition, by securing effective radiating means using the sheet
metal member and injection-molding the package body with resin, the
high power LED package of the present invention can be easily
manufactured into a simple product.
Furthermore, by fixedly wrapping the sheet metal member functioning
as radiating means and terminal in the package body of resin, the
high power LED package of the present invention can be provided
thin and robust.
While the present invention has been shown and described in
connection with the preferred embodiments, it will be apparent to
those skilled in the art that modifications and variations can be
made without departing from the spirit and scope of the invention
as defined by the appended claims.
* * * * *