U.S. patent application number 12/081888 was filed with the patent office on 2008-11-27 for light emitting device and manufacturing method of the same.
This patent application is currently assigned to SAMSUNG ELECTRO-MECHANICS CO., LTD.. Invention is credited to Tomio Inoue, Ok Hee Shin, Tsuyoshi Tsutsui, Jae Joon Yoon.
Application Number | 20080290359 12/081888 |
Document ID | / |
Family ID | 40049818 |
Filed Date | 2008-11-27 |
United States Patent
Application |
20080290359 |
Kind Code |
A1 |
Inoue; Tomio ; et
al. |
November 27, 2008 |
Light emitting device and manufacturing method of the same
Abstract
There is provided a light emitting device including: a package
body having first and second circumferential surfaces and a
plurality of side surfaces formed therebetween, the package body
defined into first and second level areas including the first and
second circumferential surfaces, respectively; first and second
external terminal blocks each having an electrical contact part; an
LED chip disposed between the first and second external terminal
blocks in the first level area and having an electrode surface
where first and second electrodes are formed; and wires
electrically connected to first and second electrodes of the LED
chip to the electrical contact parts of the first and second
external terminal blocks, respectively.
Inventors: |
Inoue; Tomio; (Suwon,
KR) ; Tsutsui; Tsuyoshi; (Suwon, KR) ; Yoon;
Jae Joon; (Suwon, KR) ; Shin; Ok Hee; (Suwon,
KR) |
Correspondence
Address: |
MCDERMOTT WILL & EMERY LLP
600 13TH STREET, N.W.
WASHINGTON
DC
20005-3096
US
|
Assignee: |
SAMSUNG ELECTRO-MECHANICS CO.,
LTD.
|
Family ID: |
40049818 |
Appl. No.: |
12/081888 |
Filed: |
April 23, 2008 |
Current U.S.
Class: |
257/98 ;
257/E33.059; 438/27 |
Current CPC
Class: |
H01L 2224/48091
20130101; H01L 24/97 20130101; H01L 2924/12041 20130101; H01L
33/0095 20130101; H01L 33/483 20130101; H01L 2924/12035 20130101;
H01L 33/52 20130101; H01L 2224/48091 20130101; H01L 2924/12035
20130101; H01L 2224/48465 20130101; H01L 2924/00014 20130101; H01L
2224/48465 20130101; H01L 2224/48091 20130101; H01L 2924/12041
20130101; H01L 2924/00 20130101; H01L 2924/00 20130101; H01L
2924/00 20130101; B29C 39/42 20130101 |
Class at
Publication: |
257/98 ; 438/27;
257/E33.059 |
International
Class: |
H01L 33/00 20060101
H01L033/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 23, 2007 |
KR |
10-2007-0039402 |
Apr 22, 2008 |
KR |
10-2008-0036995 |
Claims
1. A method of manufacturing a light emitting device, the method
comprising: providing a plurality of light emitting diode chips
each having an electrode surface where both electrodes are formed,
and a plurality of external terminal blocks, each of the external
terminal blocks having an electrical contact part exposed on at
least one surface thereof; attaching the external terminal blocks
and the light emitting diode chips on a first sheet such that the
electrode surface and an exposed surface of the electrical contact
part are located at a top and each of the light emitting diode
chips is disposed between the external terminal blocks; connecting
the electrodes of the light emitting diode chip to exposed surfaces
of the electrical contact parts of adjacent ones of the external
terminal blocks by wires, respectively; forming a chip array
structure by attaching a spacer having a height greater than a
height of the wires on the first sheet to surround an arrangement
area of the external terminal blocks and the light emitting diode
chips; disposing the chip array structure inside a chamber and
decompressing the chamber inside to be in one of a low pressure and
vacuum state; dropping a curable liquid resin to be filled in the
arrangement area surrounded by the spacer; attaching a second sheet
on the spacer when the curable liquid resin is filled inside the
chip array structure; curing the curable liquid resin filled inside
the chip array structure; and cutting the chip array structure into
a desired size to obtain a plurality of light emitting devices.
2. A method of manufacturing a light emitting device, the method
comprising: providing a plurality of light emitting diode chips
each having an electrode surface where both electrodes are formed,
and a plurality of external terminal blocks, each of the external
terminal blocks having an electrical contact part exposed on at
least one surface; attaching the external terminal blocks and the
light emitting diode chips on a first sheet such that the electrode
surface and an exposed surface of the electrical contact part are
located at a top and each of the light emitting diode chips is
disposed between the external terminal blocks; connecting the
electrodes of the light emitting diode chip to exposed surfaces of
the electrical contact parts of adjacent ones of the external
terminal blocks by wires, respectively; attaching a spacer on the
first sheet to surround an arrangement area of the external
terminal blocks and the light emitting diode chips, the spacer
having a height greater than a height of the wires and having at
least one inlet formed therein; attaching a second sheet on the
spacer to produce a chip array structure having an inner space
including the arrangement area; disposing the chip array structure
inside a chamber and decompressing the chamber inside to allow the
inner space of the chip array structure to be in one of a low
pressure and vacuum state; disposing a curable liquid resin in an
area adjacent to the inlet of the spacer to seal the inner space
thereof while the chamber is decompressed; reverting the one of the
low pressure and vacuum state of the chamber back to an original
state to allow the curable liquid resin to be filled in the inner
space of the spacer through the inlet; curing the curable liquid
resin filled inside the chip array structure; and cutting the chip
array structure into a desired size to obtain a plurality of light
emitting devices.
3. The method of claim 2, wherein each of the light emitting diode
chips comprises a transparent resin layer formed on at least one
side surface thereof.
4. The method of claim 3, wherein the each of the light emitting
diode chips comprises transparent resin layers formed on the side
surface and a surface opposing the electrode surface,
respectively.
5. The method of claim 4, wherein a corresponding one of the
transparent layers formed on the surface opposing the electrode
surface comprises a phosphor powder.
6. The method of claim 2, further comprising removing the first and
second sheets, between the curing the curable liquid resin and the
cutting the chip array structure into a desired size.
7. The method of claim 2, further comprising forming a phosphor
layer on at least the light emitting diode chips out of an exposed
surface after the first sheet is removed, between the curing the
curable liquid resin and the cutting the chip array structure into
a desired size.
8. The method of claim 2, wherein the each of the external terminal
blocks comprises an insulating block having first and second
surfaces opposing each other, the electrical contact part of the
external terminal block comprises a conductive via hole extending
through the first and second surfaces of the insulating block, and
the exposed surface of the electrical contact part is the first
surface of the insulating block.
9. The method of claim 8, wherein the electrical contact part of
the external terminal block further comprises an electrode layer
formed on the first surface of the insulating block to connect to
the conductive via hole.
10. The method of claim 8, wherein the insulating block is one of a
ceramic block and a printed circuit board block.
11. The method of claim 10, wherein the ceramic block has a porous
structure.
12. The method of claim 8, wherein the cutting the chip array
structure comprises cutting the chip array structure together with
the external terminal blocks so as to expose the conductive via
hole.
13. The method of claim 12, wherein the providing a plurality of
light emitting diode chips and a plurality of external terminal
blocks comprises arranging the plurality of light emitting diode
chips and the plurality of external terminal blocks in such a way
that four of the light emitting diode chips share one of the
external terminal blocks, the cutting the chip array structure
comprises cutting the chip array structure together with the
external terminal blocks in such a way that the conductive via hole
is exposed at two side surfaces of adjacent ones of the insulating
blocks, respectively.
14. The method of claim 2, wherein the each of the external
terminal blocks has a side surface where at least one step is
formed.
15. The method of claim 2, wherein the attaching the external
terminal blocks and the light emitting diode chips on a first sheet
comprises: arranging the light emitting diode chips and the
external terminal blocks on the first sheet having a curable
material applied thereon; and curing the curable material such that
the light emitting diode chips and the external terminal blocks are
secured to each other on the first sheet.
16. The method of claim 2, further comprising disposing the curable
liquid resin inside the chamber, before the decompressing the
chamber inside, whereby the curable liquid resin is de-aired in,
the decompressing the chamber inside.
17. The method of claim 2, further comprising unloading the chip
array structure outside the chamber, before the curing the curable
liquid resin.
18. The method of claim 2, wherein the curable resin comprises an
electrically insulating high-reflectivity powder.
19. The method of claim 18, wherein the high-reflectivity powder is
a TiO.sub.2 powder.
20. The method of claim 2, further comprising: attaching a zenor
diode on one of the external terminal block and the light emitting
diode chip, after the attaching the external terminal blocks and
the light emitting diode chips, wherein the connecting the
electrodes by wires comprises connecting the zenor diode, the
electrical contact part of the external terminal block and the
electrodes of the light emitting diode chip to one another by
wires.
21. The method of claim 2, further comprising attaching a heat
radiator on the light emitting diode chip, after attaching the
external terminal blocks and the light emitting diode chips.
22. The method of claim 2, wherein the second sheet is rigid.
23. The method of claim 2, wherein the external terminal block has
a height identical to a height of the spacer, the external terminal
block has a step formed on a surface facing the light emitting
diode chip.
24. The method of claim 23, wherein the external terminal block is
formed of a conductor capable of serving as the electrical contact
part.
25. The method of claim 23, wherein the producing the chip array
structure comprises attaching the second sheet on a top of the
spacer and the top end of the external terminal block.
26. A light emitting device manufactured according to a method
defined in claim 2.
27. A light emitting device comprising: a package body having a
first circumferential surface, a second circumferential surface and
a plurality of side surfaces formed therebetween, the package body
defined into first and second level areas including the first and
second circumferential surfaces, respectively, and formed of a
curable resin; first and second external terminal blocks disposed
at both edges of the package body, respectively, each of the first
and second external terminal blocks having a first surface exposed
to the first circumferential surface of the package body, a second
surface opposing the first surface and side surfaces disposed
therebetween, and having an electrical contact part extended from
inside of the package body to an exposed portion of the first
surface; a light emitting diode chip disposed between the first and
second external terminal blocks in the first level area and having
an electrode surface where first and second electrodes are formed,
the electrode surface facing the second level area; and wires
electrically connected to first and second electrodes of the light
emitting diode chip to the electrical contact parts of the first
and second external terminal blocks, respectively.
28. The light emitting device of claim 27, wherein the light
emitting diode chip comprises a plurality of light emitting diode
chips, and each of the light emitting diode chips comprises a
transparent resin layer formed on at least a side surface thereof,
respectively.
29. The light emitting device of claim 28, wherein the each of the
light emitting diode chips comprises transparent resin layers
formed on the side surface and a surface opposing the electrode
surface.
30. The light emitting device of claim 29, wherein a corresponding
one of the transparent layers formed on the surface opposing the
electrode surface comprises a phosphor powder.
31. The light emitting device of claim 27, further comprising a
phosphor layer formed on at least an area of the light emitting
diode chip out of the first circumferential surface of the package
body.
32. The light emitting device of claim 31, wherein the curable
resin of the package body has a refractivity of 1.5 or less.
33. The light emitting device of claim 31, further comprising side
reflective layers formed on two opposing ones of the side surfaces
to cover the area of the light emitting diode chip, the side
reflective layers formed of a resin containing a high-reflectivity
powder.
34. The light emitting device of claim 27, wherein the each of the
first and second external terminal blocks has the second surface
located inside the package body and the side surfaces partially
exposed to the package body, and the electrical contact part is
formed to connect from the second surfaces of the first and second
external terminal blocks to exposed portions of the side surfaces,
respectively.
35. The light emitting device of claim 34, wherein the each of the
first and second external terminal blocks comprises an insulating
block having a first surface exposed to the second circumferential
surface of the package body and a second surface facing the second
level area, and a side surface disposed therebetween, and each of
the electrical contact parts of the first and second external
terminal blocks comprises a conductive via hole extending through
the first and second surfaces of the insulating block and exposed
at the exposed portions of the side surfaces.
36. The light emitting device of claim 35, wherein two adjacent
ones of the side surfaces of the first and second external terminal
blocks are exposed to two adjacent ones of the package body,
respectively.
37. The light emitting device of claim 35, wherein three adjacent
ones of the first and second external terminal blocks are exposed
to three adjacent ones of the package body, respectively.
38. The light emitting device of claim 35, wherein the electrical
contact part of the each of the first and second external terminal
blocks further comprises an electrode layer formed on the second
surface of the insulating block to connect to the conductive via
hole.
39. The light emitting device of claim 35, wherein the each of the
first and second external terminal blocks further comprises: a
metal layer formed on the first surface of the insulating block to
connect to the conductive via hole; and a light absorption
prevention layer formed on the first surface of the insulating
block to cover the metal layer and formed of a resin containing a
high-reflectivity powder.
40. The light emitting device of claim 35, wherein the insulating
block is one of a ceramic block and a printed circuit board
block.
41. The light emitting device of claim 40, wherein the ceramic
block has a porous structure.
42. The light emitting device of claim 41, wherein the porous
structure has a porosity of 10 to 60% and a pore diameter of 0.1 to
1.3 .mu.m.
43. The light emitting device of claim 27, wherein the each of the
first and second external terminal blocks has a step formed on a
surface facing the light emitting diode chip and has the second
surface exposed to the second circumferential surface of the
package body, and the electrical contact part is formed to connect
from the step of the each of the first and second external terminal
blocks to the exposed second surface.
44. The light emitting device of claim 43, wherein the first and
second external terminal blocks are formed of an electrically
conductive material capable of serving as the electrical contact
part.
45. The light emitting device of claim 27, wherein the curable
resin comprises an electrically insulating high-reflectivity
powder.
46. The light emitting device of claim 45, wherein the
high-reflectivity powder comprises a TiO.sub.2 powder.
47. The light emitting device of claim 27, further comprising a
zenor diode disposed in the second level area, the zenor diode
attached on one of the first surface of the each of the first and
second external terminal blocks and the electrode surface of the
light emitting diode chip to electrically connect to the electrical
contact part and one of the first and second electrodes.
48. The light emitting device of claim 27, further comprising a
heat radiator disposed in the second level area and attached on the
light emitting diode chip.
49. The light emitting device of claim 27, wherein the first and
second circumferential surfaces and side surfaces of the package
body are planar.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the priorities of Korean Patent
Application No. 2007-0039402 filed on Apr. 23, 2007, and Korean
Patent Application No. 2008-0036995 filed on Apr. 22, 2008, in the
Korean Intellectual Property Office, the disclosure of which are
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a light emitting device,
and more particularly, to a light emitting device having a
semi-conductor light emitting diode (LED) chip and a method of
manufacturing the same.
[0004] 2. Description of the Related Art
[0005] In general, a light emitting device having a light emitting
diode (LED) chip is structured as a package with a case obtained by
injection-molding a white resin together with a lead frame. In this
light emitting device, an LED chip is mounted on a groove of the
case to connect to the lead frame and then the groove is filled
with a resin. Particularly, to manufacture a white light emitting
device, a phosphor powder may be added to the resin filled in the
groove.
[0006] However, a conventional light emitting device entails
drawbacks in terms of miniaturization and yield.
[0007] For example, a side view light emitting device, which is
mainly used as a backlight source of a display of a mobile phone
and can be surface mounted, greatly needs to be thinned in line
with a thinner trend of the mobile phone. However, the conventional
light emitting device should be provided with a groove for mounting
LED chip therein, thus posing difficulty to the manufacture of a
sufficiently smaller case having the LED chip thereon.
[0008] Besides, the conventional light emitting device is
manufactured through a complicated process. That is, the case is
injection-molded, with the lead frame disposed, the LED chip is
mounted and a resin encapsulant is formed in the groove. This
undermines yield and increases manufacturing costs.
[0009] Notably, in a white light emitting device, when a liquid
resin containing a phosphor powder is dispensed, the phosphor may
be injected unevenly due to the dispensing process.
SUMMARY OF THE INVENTION
[0010] An aspect of the present invention provides a method of
manufacturing a smaller light emitting device in which a light
emitting diode (LED) chip and an electrode lead for external
connection can be integrated through a single process unlike a
conventional package process.
[0011] An aspect of the present invention also provides a novel
light emitting device which can be manufactured in a smaller size
and through a simpler process.
[0012] According to an aspect of the present invention, there is
provided a method of manufacturing a light emitting device, the
method including: providing a plurality of LED chips each having an
electrode surface where both electrodes are formed, and a plurality
of external terminal blocks, each of the external terminal blocks
having an electrical contact part exposed on at least one surface;
attaching the external terminal blocks and the LED chips on a first
sheet such that the electrode surface and an exposed surface of the
electrical contact part are located at a top and each of the LED
chips is disposed between the external terminal blocks; connecting
the electrodes of the LED chip to exposed surfaces of the
electrical contact parts of adjacent ones of the external terminal
blocks by wires, respectively; forming a chip array structure by
attaching a spacer having a height greater than a height of the
wires on the first sheet to surround an arrangement area of the
external terminal blocks and the LED chips; disposing the chip
array structure inside a chamber and decompressing the chamber
inside to be in one of a low pressure and vacuum state; dropping a
curable liquid resin to be filled in the arrangement area
surrounded by the spacer; attaching a second sheet on the spacer
when the curable liquid resin is filled inside the chip array
structure; curing the curable liquid resin filled inside the chip
array structure; and cutting the chip array structure into a
desired size to obtain a plurality of light emitting devices.
[0013] According to another aspect of the present invention, there
is provided a method of manufacturing a light emitting device, the
method including: providing a plurality of LED chips each having an
electrode surface where both electrodes are formed, and a plurality
of external terminal blocks, each of the external terminal blocks
having an electrical contact part exposed on at least one surface;
attaching the external terminal blocks and the LED chips on a first
sheet such that the electrode surface and an exposed surface of the
electrical contact part are located at a top and each of the LED
chips is disposed between the external terminal blocks; connecting
the electrodes of the LED chip to exposed surfaces of the
electrical contact parts of adjacent ones of the external terminal
blocks by wires, respectively; attaching a spacer on the first
sheet to surround an arrangement area of the external terminal
blocks and the LED chips, the spacer having a height greater than a
height of the wires and having at least one inlet formed therein;
attaching a second sheet on the spacer to produce a chip array
structure having an inner space including the arrangement area;
disposing the chip array structure inside a chamber and
decompressing the chamber inside to allow the inner space of the
chip array structure to be in one of a low pressure and vacuum
state; disposing a curable liquid resin in an area adjacent to the
inlet of the spacer to seal the inner space thereof while the
chamber is decompressed; reverting the one of the low pressure and
vacuum state of the chamber back to an original state to allow the
curable liquid resin to be filled in the inner space of the spacer
through the inlet; curing the curable liquid resin filled inside
the chip array structure; and cutting the chip array structure into
a desired size to obtain a plurality of light emitting devices.
[0014] Each of the LED chips may include a transparent resin layer
formed on at least one side surface thereof. The each of the LED
chips may include transparent resin layers formed on the side
surface and a surface opposing the electrode surface, respectively.
A corresponding one of the transparent layers formed on the surface
opposing the electrode surface may include a phosphor powder.
[0015] Before the chip array structure is diced into a desired
size, a phosphor layer may be additionally formed on at least an
area of the LED chip out of the exposed surface after removing the
first sheet.
[0016] The method may further include removing the first and second
sheets, between the curing the curable liquid resin and the cutting
the chip array structure into a desired size.
[0017] The each of the external terminal blocks may include an
insulating block having first and second surfaces opposing each
other, the electrical contact part of the external terminal block
may include a conductive via hole extending through the first and
second surfaces of the insulating block, and the exposed surface of
the electrical contact part may be the first surface of the
insulating block.
[0018] To ensure wires to be connected in a sufficient area, the
electrical contact part of the external terminal block may further
include an electrode layer formed on the first surface of the
insulating block to connect to the conductive via hole.
[0019] The insulating block may be a ceramic block or a printed
circuit board (PCB) block. The insulating block, when formed of the
ceramic block, may have a porous structure to be more strongly
bonded to the resin.
[0020] The each of the external terminal blocks may have a side
surface where at least one step is formed to be more superbly
bonded to the light emitting device.
[0021] The cutting the chip array structure may include cutting the
chip array structure together with the external terminal blocks so
as to expose the conductive via hole.
[0022] The providing a plurality of LED chips and a plurality of
external terminal blocks may include arranging the plurality of LED
chips and the plurality of external terminal blocks in such a way
that four of the LED chips share one of the external terminal
blocks, and the cutting the chip array structure may include
cutting the chip array structure together with the external
terminal blocks in such a way that the conductive via hole is
exposed at two side surfaces of adjacent ones of the insulating
blocks, respectively.
[0023] The attaching the external terminal blocks and the LED chips
on a first sheet may include: arranging the LED chips and the
external terminal blocks on the first sheet having a curable
material applied thereon; and curing the curable material such that
the LED chips and the external terminal blocks are secured to each
other on the first sheet.
[0024] The method may further include disposing the curable liquid
resin inside the chamber, before the decompressing the chamber
inside, whereby the curable liquid resin is de-aired in the
decompressing the chamber inside.
[0025] The curable resin may include an electrically insulating
high-reflectivity powder. The high-reflectivity powder may be a
TiO.sub.2 powder.
[0026] The method may further include: attaching a zenor diode on
one of the external terminal block and the LED chip, after the
attaching the external terminal blocks and the LED chips, wherein
the connecting the electrodes by wires includes connecting the
zenor diode, the electrical contact part of the external terminal
block and the electrodes of the LED chip to one another by
wires.
[0027] The method may further include attaching a heat radiator on
the LED chip, after attaching the external terminal blocks and the
LED chips.
[0028] The second sheet may be rigid. The external terminal block
may have a height identical to a height of the spacer, the external
terminal block may have a step formed on a surface facing the LED
chip and may have a step surface electrically connected to a top
end thereof.
[0029] The external terminal block may be formed of a conductor
capable of serving as the electrical contact part.
[0030] According to still another aspect of the present invention,
there is provided a light emitting device including: a package body
having a first circumferential surface, a second circumferential
surface and a plurality of side surfaces formed therebetween, the
package body defined into first and second level areas including
the first and second circumferential surfaces, respectively, and
formed of a curable resin; first and second external terminal
blocks disposed at both edges of the package body, respectively and
each having first and second surfaces and side surfaces
therebetween, each of the first and second external terminal blocks
having the first surface exposed to the first circumferential
surface of the package body and having an electrical contact part
connected from inside of the package body to another exposed
surface; an LED chip disposed between the first and second external
terminal blocks in the first level area and having an electrode
surface where first and second electrodes are formed, the electrode
surface facing the second level area; and wires electrically
connected to first and second electrodes of the LED chip to the
electrical contact parts of the first and second external terminal
blocks, respectively.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] The above and other aspects, 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, in which:
[0032] FIGS. 1A to 1D are cross-sectional views illustrating a
manufacturing process of a chip array structure in a method of
manufacturing a light emitting device according to a first
embodiment of the invention;
[0033] FIGS. 2A to 2D are cross-sectional views illustrating a
manufacturing process of an individual light emitting device in a
method of manufacturing a light emitting device according to a
first embodiment of the invention;
[0034] FIG. 3 is a plan view illustrating arrangement of FIG. 1A,
seen from top;
[0035] FIG. 4A is side cross-sectional view and 4B is an internal
plan view illustrating a vacuum chamber applicable to the present
invention, respectively.
[0036] FIG. 5A is a plan view and FIG. 5B is a side cross-sectional
view illustrating a light emitting device, respectively according
to the present invention;
[0037] FIG. 6A is a plan view and FIG. 6B is a side cross-sectional
view illustrating a light emitting device, respectively according
to the present invention;
[0038] FIGS. 7A and 7B are perspective views illustrating an
external terminal block applicable to the first embodiment of the
present invention;
[0039] FIGS. 8A to 8D are cross-sectional views illustrating a
manufacturing process of a chip array structure in a method of
manufacturing a light emitting device according to a modified
example of the first embodiment of the invention;
[0040] FIG. 9 is a plan view illustrating an arrangement shown in
FIG. 8A, seen from top;
[0041] FIGS. 10A to 10E are cross-sectional views illustrating a
manufacturing process of an individual light emitting device in a
method of manufacturing a light emitting device according to a
modified example of the first embodiment of the invention;
[0042] FIG. 11A is a plan view and FIG. 11B is a side
cross-sectional view illustrating a light emitting device according
to a first embodiment of the invention;
[0043] FIG. 12 is a plan view illustrating a light emitting device
according to a second embodiment of the invention;
[0044] FIGS. 13A to 13D are cross-sectional views illustrating a
manufacturing method of a chip array structure in a method of
manufacturing a light emitting device according to a second
embodiment of the invention;
[0045] FIGS. 14A to 14D are cross-sectional views illustrating a
manufacturing process of an individual light emitting device in a
method of manufacturing a light emitting device according to a
second embodiment of the invention;
[0046] FIG. 15A is a plan view and FIG. 15B is a side
cross-sectional view illustrating the light emitting device shown
in FIG. 12D, respectively;
[0047] FIG. 16 is a plan view illustrating an arrangement shown in
FIG. 13D, seen from top;
[0048] FIG. 17A is a side cross-sectional view and FIG. 17B is an
internal plan view illustrating a vacuum chamber applicable to the
present invention, respectively; and
[0049] FIG. 18A is a top plan view and FIG. 18B is a side
cross-sectional view illustrating an external terminal block
applicable to the second embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0050] Exemplary embodiments of the present invention will now be
described in detail with reference to the accompanying
drawings.
[0051] A method of manufacturing a light emitting device according
to a first embodiment of the present invention will be more easily
understood by way of exemplary processes shown in FIGS. 1 and
2.
[0052] FIGS. 1A to 1D illustrate processes of manufacturing a chip
array structure necessary for manufacturing a light emitting device
according to a first embodiment of the invention.
[0053] As shown in FIG. 1A, external terminal blocks 15 and light
emitting diode (LED) chips 12 are arranged on a first sheet 11a'
having a curable material R applied thereon.
[0054] Each of the LED chips 12 has electrodes 12a and 12b of
opposite polarities formed on one surface (hereinafter, "electrode
surface"). As in the present embodiment, resin layers 14 may be
formed on a surface opposing the electrode surface and side
surfaces of each of the external terminal blocks 15. The resin
layers 14 may contain a phosphor powder for converting wavelength.
Particularly, a phosphor-containing portion of the resin layers may
be provided on a surface serving as a light exiting surface in the
LED chip 12, i.e., the surface opposite to the electrode
surface.
[0055] The external terminal block 15 of the present embodiment
includes an insulating block 15a and an electrical contact part 15b
extending through both surfaces of the external terminal block and
formed of a conductor. The electrical contact part 15b is exposed
on at least one surface of the external terminal block 15 to be
brought in contact with the LED chip 12. This external terminal
block 15 is provided as an external terminal of a final light
emitting device. A connection area for this external terminal can
be attained by exposing the electrical contact part 15b through a
diced surface when diced in a later dicing process.
[0056] The shape of the external terminal block 15, and position
and shape of the electrical contact part 15b may be varied
according to a structure of a desired final light emitting device,
e.g., side view or top view light emitting device (see FIGS. 7A, 7B
and FIG. 16).
[0057] The external terminal block 15 applicable to the present
embodiment is not limited to a specific shape as long as provided
with the electrical contact part 15b exposed to connect to the
electrodes 12a and 12b of the LED chip and exposed on a surface of
the final light emitting device, i.e., after dicing. In a specific
embodiment, the external terminal block may be formed of a
conductor material to serve as the electrical contact part.
[0058] In the present embodiment, the LED chip 12 is disposed
between the external terminal blocks 15. To be connected by wires
later, the LED chip 12 and the external terminal block 15 are
arranged such that the electrode surface and an exposed surface of
the electrical contact part 15b are located at a top. FIG. 3
illustrates arrangement applicable to an exemplary embodiment of
the invention.
[0059] Referring to FIG. 3, an LED chip 12 is illustrated as LED
chip arrays A arranged in a line. Each of these LED chip arrays A
is construed as a structure where a resin layer 14 formed has not
been diced into individual chips. Of course, alternatively,
individual chips may be arranged in place of adopting the LED chip
array.
[0060] In the arrangement, four LED chips 12 share one external
terminal block 15. Therefore, when diced along dotted lines in a
following process, the external terminal block 15 is diced into
quarters to produce four individual light emitting devices. Here,
when the external terminal block 15 is diced into quarters, a
conductive via hole, i.e., the electrical contact part 15b is diced
at the same time, thereby exposing the electrical contact part 15b
at two adjacent side surfaces formed by the dicing. The exposed
surfaces of the electrical contact part can serve as a connection
area for the external terminal block 15. The external terminal of
the light emitting device can be configured without being limited
to the above. In alternative arrangement, two or other number of
LED chips may share one external terminal block.
[0061] Thereafter, as shown in FIG. 1B, the LED chip 12 and the
external terminal block 15 arranged on the first sheet 11a' are
fixed to the first sheet 11a using an adhesive curable material
R.
[0062] To perform this process, the LED chips 12 and the external
terminal blocks 15 may be pressed adequately and then an adhesive
curable material may be cured appropriately. For example, in a case
where a curable material is an ultra violet (UV) curable resin, the
ultra violet may be irradiated to attach the LED chips 12 and the
external terminal blocks 15 on the first sheet 11a after performing
pressing.
[0063] Then, as shown in FIG. 1C, the electrodes 12a and 12b of the
LED chip 12 are connected to the exposed surfaces of the electrical
contact parts 15b of adjacent ones of the external terminal blocks
15 by wires, respectively.
[0064] In the arrangement process described above (see FIG. 1A),
the LED chip 12 and the external terminal block 15 are arranged
such that the electrode surface and the exposed surface of the
electrical contact part 15b are provided on a top. Thus this
wire-bonding process can be performed easily.
[0065] Next, as shown in FIG. 1D, a spacer 17 is attached on the
first sheet 11a to surround an arrangement area defined by the
external terminal blocks 15 and the LED chips 12.
[0066] The spacer 17 defines an area where the resin is filled in a
following process of filling the resin. Therefore, to ensure the
wires 16a and 16b to be positioned inside a package body formed of
the resin, the spacer 17 has a height greater than a height of the
wires 16A and 16B. The spacer 17 can be attached using an adhesive
resin or a curable material.
[0067] These processes allow for a chip array structure applicable
to the first embodiment of the present invention. The chip array
structure shown in FIG. 1D can be manufactured into a plurality of
light emitting devices through a series of processes such as
filling of resin and dicing as shown in FIGS. 2A to 2D.
[0068] First, as shown in FIG. 2A, a curable liquid resin 18' is
dropped onto the arrangement area inside the spacer 17 to fill the
arrangement area surrounded by the spacer 17.
[0069] The curable liquid resin 18' may be dropped in a sufficient
amount to fill an inner space of the spacer. More specifically, the
curable liquid resin 18' may be dropped to at least a height of the
spacer 17.
[0070] The curable liquid resin 18' may be a transparent resin
containing an electrically insulating and high-reflectivity powder
to prevent loss from light absorption by other components and
enhance light radiation efficiency. The high-reflectivity powder
may be a TiO.sub.2 powder. The transparent resin may adopt a
silicon resin, an epoxy resin and a combination thereof.
[0071] The dropped resin 18' can be adequately positioned between
the LED chips 12 and the external terminal blocks 15 by adjusting
conditions such as viscosity of the resin.
[0072] In the present embodiment, to fill the resin, the chip array
structure is disposed in a vacuum chamber and the chamber is
decompressed to be in a low pressure or vacuum state. For example,
this process can be performed in a vacuum chamber shown in FIGS. 4A
and 4B.
[0073] As shown in FIGS. 4A and 4B, a vacuum chamber apparatus 30
includes a chamber 31, a vacuum valve 36 provided at one side of
the chamber 31 and a shelf 33 provided inside the chamber 31.
[0074] The chamber 31 has an inner space decompressed through a
vacuum valve 36 to be in a vacuum or low pressure state. The
chamber 31 may additionally include a resin storage 34 to drop the
curable liquid resin 18' onto a desired location. The resin storage
34 assures de-airing of the curable resin 18', which is to be
filled under this decompression condition.
[0075] Before decompressing the inside of the chamber 31, the
curable liquid resin may be previously positioned inside the
chamber 31 to be more effectively de-aired.
[0076] Thereafter, as shown in FIG. 2B, the chamber 31 is reverted
to its original state and then a second sheet 11b is attached onto
the spacer 17.
[0077] When the second sheet 11b is attached on the spacer 17, the
curable liquid resin 18' can be adjusted in level to be equivalent
to a height of the spacer 17. Moreover, an appropriate pressure may
be applied when the second sheet 11b is attached, thereby allowing
the curable liquid resin 18' to be injected into an area between
the LED chips 12 and external terminal blocks 15 more effectively.
This process along with other following processes may be carried
out while the chip array structure is unloaded after the chamber is
reverted to its originals state.
[0078] Thereafter, as shown in FIG. 2C, the curable liquid resin
18' filled inside the chip array structure is cured.
[0079] The curing can be performed by using heat or ultraviolet ray
irradiation depending on type of the resin. In this process, the
curing may be directly performed inside the chamber 31.
Alternatively, the chip array structure may be picked up and cured
using an additional pressing apparatus P outside. The cured resin
18 secures the LED chips 12 and the external terminal blocks 15
together to form a single structure. Also, the cured resin 18 may
protect the wires 16 electrically connecting the chips 12 and the
blocks 15.
[0080] Subsequently, as shown in FIG. 2D, the first and second
sheets 11a and 11b are removed from the chip array structure, and
the chip array structure is diced into a desired size to produce a
plurality of light emitting devices 10.
[0081] The first and second sheets 11a and 11b can be removed from
the chip array structure by a suitable chemical and mechanical
method known in the art. After the sheets 11a and 11b are removed,
the chip array structure is diced by a dicing apparatus D.
[0082] In the arrangement of FIG. 1A and FIG. 3, the chip array
structure is diced into quarters so that the divided external
terminal blocks 15 serve as external terminals for four light
emitting devices, respectively. Also, the chip array structure may
be diced in such a way that the electrical contact part 15b is
exposed at two adjacent side surfaces through a diced surface of
the external terminal blocks 15.
[0083] FIG. 5A is a plan view and FIG. 5B is a side cross-sectional
view illustrating a light emitting device, respectively according
to a first embodiment of the present invention.
[0084] Referring to FIGS. 5A and 5B, the light emitting device 20
includes a package body 28 formed of a curable resin. The package
body 28 has first and second circumferential surfaces 28a and 28b
opposing each other and a side surface 28c disposed therebetween.
The first and second circumferential surfaces 28a and 28b and the
side surface 28c of the package body 28 are planar. In the present
embodiment, each of the surfaces of the package body is planar but
may be varied through additional machining.
[0085] The package body 28 may be a transparent resin containing an
electrically insulating and high-reflectivity powder to reduce loss
from light absorption by other components. The high-reflectivity
powder may adopt a TiO.sub.2 powder.
[0086] First and second external terminal blocks 25 are disposed at
both edges of the package body 28. Each of the first and second
external terminal blocks 25 includes a first surface exposed to the
first circumferential surface 28a of the package body 28 and a
second surface opposing the first surface. The external terminal
block 25 of the present embodiment includes an insulating block 25a
and an electrical contact part 25b extending through the first and
second surfaces.
[0087] To explain the structure of the light emitting device 20 of
the present invention more easily, the package body 28 is construed
to be divided into first and second level areas L1 and L2 including
the first and second circumferential surfaces 28a and 28b,
respectively based on an electrode surface of the LED chip 22 where
the electrodes 22A and 22B are formed.
[0088] The LED chip 22 is located between the first and second
external terminal blocks 25 in the first level area L1 and the
electrode surface where the first and second electrodes 22a and 22b
are formed faces the second level area L2. The LED chip 22 can be
connected to a portion of the connector 25b exposed to the second
surface of each of the first and second external terminal blocks 25
by wires 26a and 26b. Also, the wires 26 can be located in the
second level area L2 and across a portion L1 of the first level
area of the package body 28 to be protected.
[0089] In the present embodiment, as described regarding the
arrangement shown in FIG. 3 and the dicing process of FIG. 2D, the
each external terminal block 25 may be diced into quarters so that
the electrical contact part 25b is exposed at two adjacent diced
surfaces. Here, a side surface of the package body 28 where the
electrical contact part 25b of the external terminal block 25 is
exposed serves as an area where the light emitting device 20 is
mounted. The light emitting device 20 with this structure can be
very effectively utilized as a side view LED package.
[0090] Particularly, the light emitting device 20 of the present
embodiment does not employ an additional case structure, thereby
realizing sufficient compactness. Moreover, unlike a conventional
method entailing an additional process of forming a resin
encapsulant aside from a process of injection-molding the case
structure, the whole structure can be manufactured in a single
process and does not require additional machining for a lead frame.
This advantageously allows compact packages to be
mass-produced.
[0091] The light emitting device of the present embodiment may be
varied depending on a desired package structure. For example, a
necessary component can be adequately added. As a representative
example, the light emitting device may include a heat radiator for
radiating heat effectively and/or a zenor diode for voltage
resistance characteristics.
[0092] FIG. 6A is a plan view and FIG. 6B is a side cross-sectional
view illustrating a light emitting device, respectively according
to another exemplary embodiment of the present invention.
[0093] Referring to FIG. 6A and FIG. 6B, in a similar manner to the
light emitting device 20 shown in FIGS. 5A and 5B, the light
emitting device 30 includes a package body 38 and first and second
external terminal blocks 35 disposed at both edges of the package
body 38. The light emitting device 30 also includes an LED chip 32
disposed between the first and second external terminal blocks.
[0094] The LED chip 32 is located in a first level area L1, and
first and second electrodes 32a and 32b may be connected to an
electrical contact part 35b of each of the first and second
external terminal blocks 35 by wires 36a and 36b, respectively.
Furthermore, the wires 36a and 36b can be located in a second level
area L2 of the package body 38 to be protected.
[0095] The light emitting device 30 of the present embodiment
includes a zenor diode 37 disposed on one of the external terminal
blocks 35 in the second level area L2. The zenor diode 37 can be
electrically connected to the LED chip 32 by wire-bonding or
surface mount technology. That is, as in the present embodiment,
the zenor diode 37 has one electrode connected to the electrical
contact part 35b of one of the external terminal blocks 35 by
surface mount technology. Also, the zenor diode 37 has another
electrode connected to the electrical contact part 35b of the other
external terminal block 35 by wires 36c.
[0096] Alternatively, the zenor diode 37 may be bonded with
different configurations depending on location of the electrodes
and mounting position thereof. For example, alternatively, the
zenor diode 37 may be mounted on an electrode surface of the LED
chip 32. Here, the zenor diode 37 may have both electrodes
connected to the electrical contact part by wires,
respectively.
[0097] In addition, the light emitting device 30 may further
include a heat radiator 39 located in the second level area L2 and
attached on the LED chip 32. The heat radiator 39 may be formed of
a known material having excellent thermal conductivity.
[0098] As described above, optionally, the light emitting device 30
may include the zenor diode 37 and/or the heat radiator 39. This
process can be performed by a manufacturing process of the chip
array structure shown in FIGS. 1A to 1D. Such a process may be
performed before the wires bonding process (FIG. 1C).
[0099] FIGS. 7A and 7B are perspective views illustrating an
external terminal block applicable to the first embodiment of the
present invention. Here, the external terminal block is applicable
to the arrangement of FIG. 3 and a final light emitting device may
be divided into quarters along dotted lines. Alternatively, the
external terminal block may be configured as a board shown in FIG.
9.
[0100] An external terminal block 45 of FIG. 7A includes an
insulating block 45a. This insulating block 45a may be formed of a
ceramic body. Notably, the ceramic body may be formed of a porous
structure having a plurality of pores h to be more highly bonded to
a resin of the package body. To this end, the insulating block 45a
of the porous structure may have a porosity of about 10 to 60% and
a pore diameter of about 0.1 to 1.3 .mu.m.
[0101] An electrical contact part 45B of the external terminal
block 45 may include a conductive via hole V1 extending through
both surfaces of the insulating block 45 and an electrode layer E1
connected to the conductive via hole V1. Here, the electrode layer
E1 allows electrodes of the LED chip to be wire-bonded thereto in a
greater bonding area, thereby diminishing defects associated with
bonding.
[0102] When the conductive via hole V1 is formed, optionally, a
metal layer M made of Au or Ag may be, formed on the external
terminal block 45. This metal layer M absorbs light generated from
the LED chip inside the package structure, potentially degrading
optical efficiency. To prevent this, the external terminal block 45
may further include a light absorption prevention layer 46 to at
least cover the metal layer M. The light absorption prevention
layer 46 may be formed of a resin layer containing a
high-reflectivity powder such as TiO.sub.2.
[0103] An external terminal block 55 shown in FIG. 7B includes an
insulating block 55a. This insulating block 55a has a step S
provided at a side surface of the external terminal block 55. In a
similar manner to the porous structure described above, this step S
structure can be more highly bonded to the resin of the package
body.
[0104] The electrical contact part 55b of the external terminal
block 55 may include a via hole V2 extending through both surfaces
of the insulating block 55 and an electrode layer E2 connected to
the conductive via hole V2. Here, the electrode layer E2 ensures
electrodes of the LED chip to be wires-bonded thereto in a greater
bonding area, thereby diminishing defects associated with
bonding.
[0105] FIGS. 8A to 8D are cross-sectional views illustrating a
manufacturing process of a chip array structure in a method of
manufacturing a light emitting device according to a modified
example of the first embodiment of the invention.
[0106] As shown in FIG. 8A, external terminal blocks 65 and LED
chips 62 are arranged on a first sheet 61a' having a curable
material R applied thereon.
[0107] Each of the LED chips 62 is provided with an electrode
surface where electrodes 62a and 62b of opposite polarities are
formed. In the present embodiment, unlike the embodiment of FIG. 1,
a resin layer is not additionally formed on a surface of the LED
chip 62.
[0108] Similarly to FIG. 1, each of the external terminal block 65
may include an insulating block 65a, and an electrical contact part
65b extending through both surfaces of the external terminal block
and formed of a conductor. The external terminal block is diced in
a later dicing process (see FIG. 2E) and the electrical contact
part 65b may be exposed at a diced surface to ensure a connection
area for the external terminal block.
[0109] In the present embodiment, the LED chip 62 is disposed
between the external terminal blocks 15. The LED chip 62 and the
external terminal block 65 are arranged such that the electrode
surface and an exposed surface of the electrical contact part 65b
are located at a top.
[0110] In the arrangement of the present embodiment, as shown in
FIG. 9, an external terminal block 65 is configured as a board.
This external terminal block 65 can be easily manufactured by
adopting a printed circuit board (PCB). Also, when diced along
dotted lines in a later process, an electrical contact part 65b of
the external terminal block 65 is diced into quarters to act as
four respective light emitting devices. Here, the electric contact
part 65b may be exposed on two adjacent side surfaces formed by the
dicing to ensure a connection area for external terminals. The
external terminals for the light emitting devices may be formed by
the method described above but not limited thereto. In alternative
arrangement, two or other number of LED chips may share the
external terminal block.
[0111] Thereafter, as shown in FIG. 8B, the LED chip 62 and the
external terminal block 65 arranged are attached on the first sheet
61a using an adhesive curable material R.
[0112] The LED chips 62 and the external terminal blocks 65 can be
attached on the first sheet 61a after appropriately pressing the
LED chips 62 and the blocks 65 and performing curing with the
adhesive curable material.
[0113] Next, as shown in FIG. 8C, the electrodes 62a and 62b of the
LED chip 62 are connected to exposed surfaces of the electrical
contact parts of adjacent ones of the external terminal blocks 65
by wires, respectively.
[0114] Afterwards, as shown in FIG. 8D, a spacer 67 is attached on
the first sheet 61a to surround an arrangement area of the external
terminal blocks 65 and the LED chips 62.
[0115] To ensure the wires 66A and 66B to be positioned inside a
package body formed of the resin, the spacer 67 has a height
greater than a height of the wires 66a and 66b. The spacer 67 can
be attached using an adhesive resin or a curable material.
[0116] These processes allow for a chip array structure applicable
to the present embodiment. The chip array structure shown in FIG.
8D can be manufactured into a plurality of light emitting devices
through a series of processes such as filling of resin and dicing
as shown in FIGS. 9A to 9E.
[0117] Unlike the embodiment of FIG. 1, the LED chip 62 of the
present embodiment does not include a resin layer formed on a
surface thereof. The light emitting device may require formation of
a phosphor layer for converting wavelength. Therefore, the present
embodiment suggests a novel process of forming a phosphor layer.
This process can be understood by way of processes shown in FIGS.
9A to 9E.
[0118] First, as shown in FIG. 10A, a curable liquid resin 68' is
dropped onto an arrangement area inside a spacer 67 to be filled in
the arrangement area surrounded by the spacer 67.
[0119] The curable liquid resin 68' may be dropped in a sufficient
amount to fill an inner space of the spacer. Particularly, the
curable liquid resin 68' may be dropped to at least a height of the
spacer 67.
[0120] In the present embodiment, to fill the resin, a chip array
structure is disposed in a vacuum chamber and the chamber is
decompressed to be in a low pressure or vacuum state. For example,
in a similar manner to the embodiment shown in FIG. 1, this process
can be performed using the vacuum chamber shown in FIG. 4A and FIG.
4B.
[0121] The curable liquid resin of the present embodiment may have
low refractivity to prevent light form being guided into the
package body and facilitate light extraction in a desired
direction. The curable liquid resin may utilize a transparent
liquid resin having a refractivity of about 1.5 or less.
[0122] Thereafter, as shown in FIG. 10B, the chamber is reverted
back to its original state and then a second sheet 61b is attached
onto the spacer 67.
[0123] When the second sheet 61b is attached on the spacer 67, the
curable liquid resin 68' can be adjusted in level to be equivalent
to a height of the spacer 67. Moreover, an appropriate pressure may
be applied when the second sheet 61b is attached, thereby allowing
the curable liquid rein 68' to be injected into an area between the
LED chips 62 and external terminal blocks 65 more effectively. This
process along with other following processes may be carried out
while the chip array structure is unloaded after the chamber is
reverted back to its original state.
[0124] Next, as shown in FIG. 10C, the curable liquid resin 68'
filled inside the chip array structure is cured.
[0125] The curing can be performed by using heat or irradiating
ultraviolet ray depending on type of the resin. In this process,
the curing may be directly performed inside the chamber. However,
as in the present embodiment, the chip array structure may be
picked up and cured using an additional pressing apparatus P
outside. The cured resin 68 secures the LED chips 62 and the
external terminal blocks 65 together to form a single structure.
Also, the cured resin 68 can protect wires 66A and 66B electrically
connecting the chip 62 to the block 65 to each other.
[0126] Subsequently, as shown in FIG. 10D, the first and second
sheets 61a and 61b are removed from the chip array structure, and a
phosphor layer 64 is formed on an exposed surface of the LED chip
where the first sheet 61a is removed.
[0127] The first and second sheets 61a and 61b can be removed from
the chip array structure by a suitable chemical and mechanical
method known in the art. The phosphor layer 69 is formed on a light
exiting surface, i.e., an area corresponding to at least the LED
chip 62.
[0128] Thereafter, as shown in FIG. 10E, the chip array structure
is diced into a plurality of light emitting devices 60.
[0129] The dicing can be performed by a suitable dicing apparatus.
As in the present embodiment, when four LED chips 62 share one
external terminal block 65, the external terminal block 65 is diced
into quarters to act as respective light emitting devices 60. Here,
a conductive via hole, which is the electrical contact part 65b, is
diced together with the external terminal block 65 to expose the
electrical contact part 65b at two adjacent side surfaces. The
exposed surface of the electrical contact part may serve as an area
for connecting the external terminal.
[0130] FIG. 11A is a plan view and FIG. 11B is a side
cross-sectional view illustrating a light emitting device according
to another exemplary embodiment of the invention.
[0131] Referring to FIGS. 11A and 11B, the light emitting device 70
includes a package body 78 formed of a curable resin. The package
body 78 has first and second circumferential surfaces 78a and 78b
opposing each other and a side surface 78c disposed therebetween.
The first and second circumferential surfaces 78a and 78b and the
side surface 78c of the package body 78 are planar.
[0132] First and second external terminal blocks 75 are disposed at
both edges of the package body 78. Each of the first and second
external terminal blocks 75 includes a first surface exposed to the
first circumferential surface 78a of the package body 78 and a
second surface opposing the first surface. The external terminal
block 75 of the present embodiment includes an insulating block 75a
and an electrical contact part 75b extending through the first and
second surfaces.
[0133] The LED package body 78 is construed to be divided into
first and second level areas L1 and L2 including the first and
second circumferential surfaces 78a and 78b, respectively based on
a surface of the LED chip 72 where the electrodes 72a and 72b are
formed.
[0134] The LED chip 72 is located between the first and second
external terminal blocks 75 in the first level area L1 and an
electrode surface where the first and second electrodes 72a and 72b
are formed faces the second level area L2. The LED chip 72 can be
connected to a portion of the electrical contact part 75b exposed
to the second surface of each of the first and second external
terminal blocks 75 by wires 76a and 76b.
[0135] Also, the wires 76 can be positioned in the second level
area L2 of the package body 78 to be protected. A surface of the
LED chip 72 opposite to the electrode surface is exposed to the
first circumferential surface 78a. The first circumferential
surface 78a of the package body 78 is provided as a light exiting
surface. A phosphor layer is provided on the first circumferential
surface 78a of the package body to include at least the LED chip
72.
[0136] The curable resin of the package body 78 may have low
refractivity to prevent light generated from the LED chip 72 from
being guided into the package body 78 and facilitate extraction of
light toward the phosphor layer 79. The curable resin may utilize a
transparent resin having a refractivity of about 1.5 or less.
[0137] Furthermore, as shown in FIGS. 11A and 11B, the light
emitting device 70 further includes side reflective layers 74
formed on two opposing side surfaces of the light emitting device
70 to at least cover an area where the LED chip 72 is positioned.
The side reflective layers 74 are formed mainly on the side
surfaces where the external terminal block is not disposed to
thereby block light from propagating to a side of the package body
78. The side reflective layers 74 may be formed of a resin
containing a high-reflectivity power such as TiO.sub.2.
[0138] In the present embodiment, the external terminal block 75 is
structured such that the electrical contact part 75b is exposed at
two adjacent diced surfaces. Here, a side surface of the package
body 28 where the electrical contact part 25b of the external
terminal block 25 is exposed serves as an area where the light
emitting device 20 is mounted. The light emitting device 70 with
this structure can be very effectively utilized as a side view LED
package. Moreover, the external terminal block may be variously
modified in structure.
[0139] For example, as shown in FIG. 9, when the external terminal
block configured as a board is employed, the external terminal
block of a final individual light emitting device may be exposed to
three adjacent ones of the side surfaces of the package body, as
shown in FIG. 1A.
[0140] Alternatively, when the external terminal block 15 shown in
FIG. 3 is employed, the external terminal block of the final
individual light emitting device may be exposed to two adjacent
ones of the side surfaces of the package body, as shown in FIG. 12.
Also, a corresponding one of the side surfaces of the package body
where the electrical contact part of the external terminal block is
exposed serves as an area where the light emitting device is
mounted. Particularly, in the present embodiment, the electrodes
are not exposed on a corresponding one of the side surfaces
opposing the mounting surface of the light emitting device. This
accordingly prevents short of the package resulting from a metal
cover placed after setting.
[0141] Unlike the aforesaid first embodiments, the second
embodiment of the present embodiment employs a novel process of
filling a resin by vacuum suction. FIGS. 13A to 13E are
cross-sectional views illustrating a manufacturing process of a
chip array structure in a method of manufacturing a light emitting
device according to a second embodiment of the invention.
[0142] First, as shown in FIG. 13A, external terminal blocks 85 and
LED chips 82 are arranged on a first sheet 81a' having a curable
material R applied thereon.
[0143] Each of the LED chips 82 has an electrode surface where
electrodes 82A and 82B of opposite polarities are formed. The LED
chip 82 may include resin layers 84 formed on a surface opposite to
the electrode surface and a side surface, respectively. The resin
layers 84 may include a phosphor powder for converting wavelength.
Particularly, a phosphor-containing portion of the resin layers may
be provided on the surface opposite to the electrode surface, which
will serve as a light exiting surface of the LED chips 82.
[0144] The external terminal block 85 of the present embodiment is
formed of a conductor block having a step structure. A step surface
85a of the external terminal block 85 is connected to electrodes
82a and 82b of the LED chip 82. Also, a top end 85b of the external
terminal block 85 serves as a connection area for a final light
emitting device. To this end, the external terminal block may have
a thickness identical to a height of the final light emitting
device.
[0145] The LED chips and external terminal blocks of the present
embodiment are arranged in a similar manner to those of the first
embodiment.
[0146] Thereafter, as shown in FIG. 13B, the LED chip 82 and the
external terminal block 85 arranged on the first sheet 81a' are
attached by curing an adhesive material R on the first sheet
81a.
[0147] To perform this process, the LED chips 82 and the external
terminal block 85 may be pressed adequately and then an adhesive
curable material may be cured. For example, in a case where a
curable material is an ultraviolet ray (UV) curable resin, the
ultraviolet ray may be irradiated to attach the LED chips 82 and
the external terminal blocks 85. In the present embodiment, the
adhesive curable material is additionally applied but the first
sheet 81a may be a curable resin.
[0148] Next, as shown in FIG. 13C, the electrodes 82A and 82B of
each of the LED chips 82 are connected to adjacent ones of the
external terminal blocks 85.
[0149] In each of the external terminal blocks 85 of the present
embodiment, a portion connected to the LED chip 82 serves as a step
surface 85a. The step surface 85a of the external terminal block 85
as well as the electrode surface is arranged to be located at a
top, thereby facilitating wires bonding. Moreover, in the present
embodiment, the external terminal block 85 is formed of a
conductive material. This accordingly allows a top end 85b to be
exposed in a final package to be electrically connected to the step
surface. Therefore, the top end 85b of the external terminal block
85 can serve as an area where the final light emitting device is
connected to the outside.
[0150] Thereafter, as shown in FIG. 13D, a spacer 87 is disposed to
surround the LED chip 82 and the external terminal block 85 and
provided with at least one inlet (I in FIG. 16). A second sheet 81b
is attached on the spacer 87.
[0151] The spacer 87 has a predetermined height and together with
the first and second sheets 81a and 81b, defines an inner space of
the chip array structure. The spacer may have a height equivalent
to a thickness of the final light emitting device. In the present
embodiment, the spacer has a height substantially identical to a
thickness of the external terminal block.
[0152] As shown in FIG. 16, the inner space of the chip array
structure has two inlets I formed on opposing side walls to be
connected to the outside. The inlets I serve as a supply conduit of
a resin surrounding a surface of the LED chip in a later
process.
[0153] As in the present embodiment, the plurality of inlets I are
formed on the opposing sides to thereby ensure smoother injection
of the resin. However, in the present invention, the inlets I are
not limited in number or position and only a single inlet may be
sufficient depending on size of the arrangement area and
arrangement spacings.
[0154] The chip array structure shown in FIG. 13D may have the
resin filled therein using a vacuum chamber shown in FIGS. 17A and
17B.
[0155] FIG. 17A is a cross-sectional view and FIG. 17B is an
internal plan view illustrating a vacuum chamber applicable to the
present invention, respectively.
[0156] As shown in FIGS. 17A and 17B, the vacuum chamber apparatus
includes a chamber 91, a vacuum value 96 provided at one side of
the chamber 91 and a shelf disposed inside the chamber 91. The
inner space of the chamber 91 is decompressed via a vacuum valve 96
to be changed into a vacuum or low pressure state.
[0157] A resin storage 94 is disposed on a top of the chamber 91 to
drop a curable liquid resin 88' onto a desired location. In the
present embodiment, as shown, the resin storage 94 may be disposed
in a portion adjacent to the inlets I to allow the inlets I of the
spacer 87 to be sealed.
[0158] Hereinafter, with reference to FIGS. 14A to 14D, an
exemplary method of manufacturing chip parts will be described
according to a second embodiment. The present embodiment is
construed to be implemented based on the vacuum chamber shown in
FIGS. 17A and 17B, and the method will be described in greater
detail with reference to FIGS. 14A and 14B.
[0159] As shown in FIG. 14a, with a chip array structure disposed
inside a chamber 91, the chamber has an inner space changed into a
vacuum or low pressure state via a vacuum valve 96. Also, a curable
liquid resin 88' is dropped onto inlets I of the spacer 87.
[0160] The chamber 91 may be changed into a vacuum state inside by
the decompression process, but may be in an adequate low pressure
state to ensure a resin described below to be sucked. By this
decompression process, not only the inner space of the chamber 91
but also the inner space of the chip array structure can be changed
to be under the same pressure through the inlets I.
[0161] In the decompression process, the curable liquid resin 88'
is previously disposed inside the chamber 91 to be de-aired. This
precludes a need for an additional process for de-airing the liquid
resin 88'.
[0162] Afterwards, as shown, the curable liquid resin 88' is
dropped in a sufficient amount to cover the inlets I, thereby
substantially sealing the inner space of the chip array
structure.
[0163] Then, the chamber is reverted back to its original state by
a vacuum value 96. This produces a chip array structure having the
curable liquid resin 88' filled in an inner space thereof as shown
in FIG. 12b.
[0164] In this process, the chamber 91 is drastically increased in
inner pressure but the inner space of the chip array structure can
maintain a low pressure or vacuum state by the curable liquid resin
88' sealing, even if temporality, the inlets I. This accordingly
leads to high pressure difference between the inner space of the
chip array structure and other outer space, i.e., inner space of
the chamber 91. This pressure difference allows the curable liquid
resin 88' to be injected into the inner space of the chip array
structure through the inlets I and be filled in the inner space, as
indicated with arrows of FIG. 14A. In this process, to ensure the
resin 88' to be filled more effectively, viscosity of the resin,
and position, shape and amount of the dropped resin may be
adjusted.
[0165] Thereafter, as shown in FIG. 14C, the curable liquid resin
88' filled in the inner space of the chip array structure is cured.
This curing can be performed using heat or ultraviolet ray
irradiation depending on type of resin. The curing may be directly
performed inside the chamber 91, but the chip array structure may
be picked up to be cured outside the chamber 91 by an additional
curing apparatus P. The cured resin 88 may be present on all
surfaces excluding a first surface 82a of the LED chip 82 protected
by the first sheet 81a.
[0166] Finally, the first and second sheets 81a and 81b are removed
from the chip array structure and the chip array structure is diced
into a desired size to obtain a plurality of light emitting devices
80.
[0167] The first and second sheets 81a and 81b may be removed from
the chip array structure by appropriate chemical and mechanical
methods known in the art. After the sheets 81a and 81b are removed,
the chip array structure is diced using a dicing apparatus D.
[0168] In the manufacturing method of the present embodiment, the
curable liquid resin is injected in a vacuum state. The resin
injected in a vacuum state (see FIG. 14A) allows pressure to be
imposed on the chip array structure. Thus, the second sheet should
be supported by the external terminal block. Accordingly, the
external terminal block may have a height equivalent to a height of
a package.
[0169] Of course, in a case where the second sheet is formed of a
rigid material which does not undergo warping without an additional
support structure even at a pressure applied when the resin is
injected in a vacuum state, this process of filling the resin by
vacuum suction may be beneficially applied to a light emitting
structure employing the external terminal block having a low height
as shown in FIGS. 1 and 8.
[0170] In the light emitting device of the present embodiment, the
external terminal block has a height identical to a height of the
light emitting device and a step provided on a side surface
thereof. Therefore, a step surface of the external terminal block
is connected to the LED chip through wires. Also, a top end of the
external terminal block may be exposed to serve as a connection
area for the external terminal block. This structure can be
advantageously utilized as a top view light emitting package
structure.
[0171] FIG. 15A is a plan view and FIG. 15B is a cross-sectional
view illustrating a light emitting device obtained by a
manufacturing method of FIGS. 13 and 14, respectively.
[0172] Referring to FIGS. 15A and 15B, the light emitting device
100 includes a package body 108 formed of a curable resin. The
package body 108 has first and second circumferential surfaces 108a
and 108b opposing each other and a side surface 108c disposed
therebetween. The first and second circumferential surfaces 108a
and 108b and the side surface 108c of the package body 108 are
planar.
[0173] The package body 108 may be a transparent resin containing
electrically insulating and high-reflectivity powder to reduce loss
from light absorption by other components. The high-reflectivity
powder may adopt a TiO.sub.2 powder.
[0174] First and second external terminal blocks 105 are disposed
at both edges of the package body 108. Unlike the first embodiment,
in the present embodiment, the first and second external terminal
blocks 105 each have a height identical to a height of the package
body 108 and a step is formed on a side surface facing an LED chip
102. Also, the first and second external terminal blocks 105 may be
formed of a conductive material. Therefore, a step surface 105a
which is to be connected to LED chips 102 and a top end 105b
exposed to the second circumferential surface 108b of the package
body may be electrically connected to each other.
[0175] To explain the structure of the light emitting device 100 of
the present embodiment more easily, the package body 108 is
construed to be divided into first and second level areas L1 and L2
including the first and second circumferential surfaces 108a and
108b, respectively based on a surface of the LED chip 102 where
electrodes 102a and 102b are formed.
[0176] The LED chip 102 is located between the first and second
external blocks 105 in the first level area L1 and an electrode
surface where the first and second electrodes 102a and 102b are
formed faces the second level area L2. The LED chip 102 may be
connected to step surfaces 105a of the first and second external
terminal blocks 105 by wires 106A and 106B, respectively. Also, the
wires 106A and 106B can be located in the second level area L2 of
the package body 108 to be protected.
[0177] In the light emitting device of the present embodiment, a
top end 105b of the external terminal block exposed to the second
circumferential surface 108b of the package body 108 serves as an
area where the light emitting device is connected to the outside.
This accordingly allows the light emitting device to be bonded by
surface mount technology so that the second circumferential surface
108b of the package body 108 can serve as a mounting surface. The
light emitting device 100 of this structure can be very effectively
used as a top view LED package.
[0178] In present embodiment, the external terminal block 105 is
configured such that the second circumferential surface 108b
opposing the first circumferential surface 108a provides an area
where the light emitting device can be connected to an external
circuit. To realize this structure, as described above, the
external terminal block 105 has a height identical to a height of
the package body 108 and has a step formed on a side surface
thereof to serve as an area for connecting the LED chip 102.
[0179] This external terminal block may be varied in structure.
FIG. 18A is a top plan view and FIG. 18B is a side cross-sectional
view illustrating an external terminal block applicable to the
second embodiment of the invention.
[0180] The external block 115 shown in FIGS. 18A and 18B is divided
into quarters along dotted lines to be used as respective external
terminals in an individual package.
[0181] The external terminal block 115 includes an insulating block
115a having a height substantially identical to a height of the
package body and provided with a step facing an LED chip. The
insulating block 115a may be formed of a porous ceramic body having
a plurality of pores h to be more strongly bonded to the package
body made of resin. As described above, to assure stronger bonding,
three pores may have a porosity of about 10 to 60% and a pore
diameter of about 0.1 to 1.3 .mu.m.
[0182] A step surface of the block 115 is located inside the
package body to be connected to electrodes of the LED chip. The
block 115 has a top end exposed to a mounting surface of the
package body to connect to an external circuit. To realize such an
external terminal structure, an electrode layer 115b is formed on
the top end of the external terminal block 115 along the step
surface of the external terminal block 115 to electrically connect
the LED chip to the exposed top end.
[0183] As set forth above, according to exemplary embodiments of
the invention, an additional case is not employed to achieve a
sufficiently compact and novel light emitting device. Also, unlike
a conventional technology entailing a process of forming a resin
encapsulant in addition to a process of injection-molding the case,
a whole structure is manufactured in a single process, and an
additional machining process for a lead frame is not required. This
beneficially allows for mass production of compact packages.
Moreover, the light emitting device can be sized uniformly by
suitably designing a chip array structure to ensure precise
processes, thereby producing a higher-quality light emitting device
with more efficiency.
[0184] While the present invention has been shown and described in
connection with the exemplary 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.
* * * * *