U.S. patent application number 12/581828 was filed with the patent office on 2010-02-11 for led reflecting plate and led device.
Invention is credited to Ryouji Sugiura, Hideki Yoshida.
Application Number | 20100032693 12/581828 |
Document ID | / |
Family ID | 36059926 |
Filed Date | 2010-02-11 |
United States Patent
Application |
20100032693 |
Kind Code |
A1 |
Sugiura; Ryouji ; et
al. |
February 11, 2010 |
LED REFLECTING PLATE AND LED DEVICE
Abstract
A recess is formed in a land (2) of an LED reflecting plate (1)
formed of a metal plate. The recess comprises a flat LED chip
mounting portion (7) and a reflecting portion (8) inclined with
respect to the LED chip mounting portion (7). The LED reflecting
plate (1) is mounted on a printed wiring board (25) such that the
land (2) is fitted in a first through hole (18). An LED chip (27)
mounted on the LED chip mounting portion (7) is connected to a
terminal portion (22) formed on the printed wiring board (25). The
printed wiring board (25) is diced along a third through hole (19)
to form an LED device (30) as one unit. With this arrangement, heat
radiation properties and reflecting efficiency of the LED device
(30) can be improved, and the manufacturing cost can be
decreased.
Inventors: |
Sugiura; Ryouji; (Ibaraki,
JP) ; Yoshida; Hideki; (Ibaraki, JP) |
Correspondence
Address: |
BLAKELY SOKOLOFF TAYLOR & ZAFMAN LLP
1279 OAKMEAD PARKWAY
SUNNYVALE
CA
94085-4040
US
|
Family ID: |
36059926 |
Appl. No.: |
12/581828 |
Filed: |
October 19, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10574160 |
Mar 28, 2006 |
7626211 |
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PCT/JP2005/016407 |
Sep 7, 2005 |
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12581828 |
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Current U.S.
Class: |
257/88 ; 257/98;
257/E33.067 |
Current CPC
Class: |
H01L 2224/48247
20130101; H01L 33/60 20130101; H01L 33/62 20130101; H01L 2924/00014
20130101; H01L 2924/01079 20130101; H01L 2224/48091 20130101; H01L
2924/12041 20130101; H01L 2924/01004 20130101; H01L 2924/01078
20130101; H01L 2224/48091 20130101 |
Class at
Publication: |
257/88 ; 257/98;
257/E33.067 |
International
Class: |
H01L 33/00 20100101
H01L033/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 16, 2004 |
JP |
269513/2004 |
Claims
1. An LED device comprising: an LED chip; an LED reflecting plate
made of a metal and having a recess where said LED chip is to be
mounted; and a printed wiring board on which said LED reflecting
plate is to be mounted, said printed wiring board comprising a
first through hole in which the recess of said LED reflecting plate
is to be fitted, and a terminal portion formed on a surface of said
printed wiring board to be electrically connected to said LED chip,
said LED reflecting plate comprising a flat LED chip mounting
portion which forms a bottom of the recess, and a reflecting
portion which forms a side wall of the recess and is inclined with
respect to said LED chip mounting portion, said LED device further
comprising a thin metal wire which electrically connects said LED
chip and said terminal portion of said printed wiring board, said
LED reflecting plate further comprising a flat flange around the
recess, and said printed wiring board further comprising a first
substrate formed with the first through hole, a second substrate
which sandwiches, together with said first substrate, said flange
of said LED reflecting plate the recess of which is fitted in the
first through hole, and a second through hole which is formed in
said second substrate and through which said thin metal wire
connected to said LED chip on said LED reflecting plate is
extended.
2. An LED device according to claim 1, wherein a plurality of LED
chips are mounted on each recess of said LED reflecting plate.
3. An LED device according to claim 1, wherein said printed wiring
board further comprises an electrical connection hole formed in a
portion of said second substrate which is above said flange, and a
wiring line which is formed on a surface of said second substrate
and electrically connects the electrical connection hole to said
terminal portion.
Description
TECHNICAL FIELD
[0001] The present invention relates to an LED reflecting plate and
LED device and, more particularly, to an LED reflecting plate which
improves the reflecting efficiency of an LED chip to be mounted on
it, and an LED device using the same.
BACKGROUND ART
[0002] In recent years, LED chips having high luminance have been
developed. Such LED chips are not only used as an illumination for
the ten-key pad of a conventional cellular phone or the like or as
spot illumination, but also becoming to be used as illumination for
a comparatively wide range, e.g., a reading lamp. Accordingly, the
LED chips require higher heat radiation properties.
[0003] As the first example of a conventional LED device, one
described in reference 1 (Japanese Patent Laid-Open No. 7-235696)
is available. In this LED device, a through hole is formed in an
insulating substrate. One opening of the through hole is covered
with a metal plate. A metal film is formed on the wall surface of
the through hole, the surface of the metal plate, and the surface
of the insulating substrate by plating. An LED chip is mounted on
the metal plate and is electrically connected to the metal film on
the insulating film by wire bonding.
[0004] As the second example of the conventional LED device, one as
shown in FIG. 12 is available in which a lead frame 102 formed of a
thin metal plate is subjected to resin molding, and an LED chip 103
is mounted on the lead frame 102. More specifically, a
funnel-shaped recess 101 is formed in molded resin 100. The lead
frame 102 is buried in the bottom of the recess 101. The LED chip
103 is mounted on the lead frame 102 and connected to a terminal
portion 104 of the lead frame 102 through a thin metal wire by wire
bonding.
DISCLOSURE OF INVENTION
Problem to be Solved by the Invention
[0005] In the first example of the conventional LED devices
described above, the metal film on the wall surface of the through
hole formed in the insulating substrate is formed by plating.
Accordingly, there is a limit to increasing the thickness of the
metal film, and the heat radiation properties cannot be
improved.
[0006] In contrast to this, in the second example, the lead frame
102 improves the heat radiation properties. However, a mold to form
the lead frame 102 and a mold to form the resin are required to
increase the cost. It is difficult to perform uniform-thick metal
plating on the surface of the molded resin 100. Therefore, the
reflecting efficiency of light emitted from the LED decreases.
[0007] The present invention has been made in view of the
conventional problems described above, and has as its object to
improve the heat radiation properties of an LED device.
[0008] It is another object of the present invention to improve the
reflecting efficiency of light emitted from the LED.
[0009] It is still another object of the present invention to
decrease the manufacturing cost of the LED device.
Means of Solution to the Problem
[0010] In order to achieve the above object, an LED reflecting
plate according to the present invention is characterized by
comprising a plurality of lands each comprising a recess where an
LED chip is to be mounted, a first bridging portion which connects
the plurality of lands in series, a frame having a frame shape to
surround the plurality of lands, and a second bridging portion
which connects the frame to, of the plurality of lands, lands which
are located at two ends, wherein the lands, the first bridging
portion, the second bridging portion, and the frame are made of a
metal.
[0011] An LED device according to the present invention is
characterized by comprising an LED chip, an LED reflecting plate
made of a metal and having a recess where the LED chip is to be
mounted, and a printed wiring board on which the LED reflecting
plate is to be mounted, wherein the printed wiring board comprises
a first through hole in which the recess of the LED reflecting
plate is to be fitted, and a terminal portion to be electrically
connected to the LED chip.
EFFECT OF THE INVENTION
[0012] According to the present invention, since the LED chip is
mounted on the reflecting plate made of a metal plate, the heat
radiation properties improve.
[0013] Since the reflecting plate is made of the metal plate, the
thickness of an underlying plating film formed on the reflecting
plate can be made uniform. Thus, the mirror surface effect of a
noble metal plating film formed on the underlying plating film,
aluminum deposition, or the like can improve the reflecting
efficiency.
[0014] Only a mold to form the reflecting plate must be prepared.
Thus, the cost of the mold can be decreased, and accordingly the
manufacturing cost of an LED device can be decreased.
BRIEF DESCRIPTION OF DRAWINGS
[0015] FIG. 1 is a perspective view showing the entire appearance
of an LED reflecting plate according to the first embodiment of the
present invention;
[0016] FIG. 2A is a plan view of the LED reflecting plate shown in
FIG. 1;
[0017] FIG. 2B is a sectional view taken along the line II(B)-II(B)
of FIG. 2A;
[0018] FIGS. 3A to 3F are sectional views to explain a method of
manufacturing an LED device according to the first embodiment of
the present invention;
[0019] FIGS. 4A to 4D are sectional views to explain the method of
manufacturing the LED device according to the first embodiment of
the present invention;
[0020] FIG. 5A is a sectional view of the LED device according to
the first embodiment of the present invention;
[0021] FIG. 5B is a perspective view showing the appearance of the
LED device shown in FIG. 5A;
[0022] FIG. 6 is a perspective view showing the array of LED
reflecting plates to cope with a case wherein a printed wiring
board is formed to be larger than an LED reflecting plate;
[0023] FIG. 7 is a perspective view showing an LED reflecting plate
according to the second embodiment of the present invention;
[0024] FIG. 8 is a plan view showing the arrangement of lands in an
LED reflecting plate according to the third embodiment of the
present invention;
[0025] FIG. 9 is a perspective view showing a land in an LED
reflecting plate according to the fourth embodiment of the present
invention;
[0026] FIG. 10A is a sectional view of an LED device according to
the fifth embodiment of the present invention;
[0027] FIG. 10B is a perspective view showing the outer appearance
of the LED device shown in FIG. 10A;
[0028] FIG. 11 is a sectional view of an LED device according to
the sixth embodiment of the present invention; and
[0029] FIG. 12 is a sectional view of a conventional LED
device.
BEST MODE FOR CARRYING OUT THE INVENTION
[0030] The embodiments of the present invention will be described
with reference to the drawings.
[0031] The first embodiment of the present invention will be
described with reference to FIGS. 1 to 6.
[0032] An LED reflecting plate 1 shown in FIGS. 1 and 2A comprises
a plurality of lands 2 on which LED chips 27 are to be mounted,
first bridging portions 3 which connect the plurality of lands 2 in
series, a frame 4 having a frame shape to surround the plurality of
lands 2, and second bridging portions 5 which connect, of the
plurality of lands 2, the lands at the two ends to the frame 4. The
LED reflecting plate 1 is formed from a thin phosphor bronze plate
(with a thickness of 50 .mu.m to 200 .mu.m) by punching so that one
metal plate forms the lands 2, first bridging portions 3, second
bridging portions 5, and frame 4 integrally.
[0033] The LED reflecting plate 1 is provided with four land groups
6, each comprising three lands 2 that are linearly connected in
series with the first bridging portions 3, to be parallel to each
other. The 12 lands 2 are arranged in a matrix of 4 columns.times.3
rows. Alternatively, a plurality of (to or more) land groups 6 may
be provided.
[0034] The LED reflecting plate 1 is provided with positioning
holes 11, at its two vertices located on a diagonal of the frame 4,
to be aligned with a printed wiring board 25 (to be described
later).
[0035] As shown in FIG. 2B, the land 2 of the LED reflecting plate
1 has a recess formed by drawing and a flat flange 9 around the
recess. The recess comprises a flat bottom and a side wall inclined
to form an obtuse angle with respect to the bottom. The bottom of
the recess forms an LED chip mounting portion 7 where the LED chip
27 is to be mounted, and the side wall of the recess forms a
reflecting portion 8 which reflects forward light from an LED. A
space 10 surrounded by the LED chip mounting portion 7 and
reflecting portion 8 is frustoconical. A height T1 (the height from
the lower surface of the flange 9 to the lower surface of the LED
chip mounting portion 7) of the space 10 is slightly larger than a
thickness T2 of the printed wiring board 25.
[0036] To manufacture the LED reflecting plate 1, after punching as
described above, drawing is performed. Alternatively, drawing may
be performed, and after that punching may be performed, or drawing
and punching may be performed simultaneously.
[0037] The LED reflecting plate 1 formed in this manner is
subjected to nickel plating to form an underlying plating film, and
then to silver plating to form a noble metal plating film on the
underlying plating film. In this case, since the surface of the
land 2 formed of a metal plate is subjected to plating, a nickel
plating film serving as the underlying plating film formed on the
surface of the land 2 has a uniform thickness entirely. The surface
of the silver plating film formed on the nickel plating film
accordingly forms a mirror surface having very few steps entirely.
Thus, the reflecting efficiency of the surface of the reflecting
portion 8 can be improved.
[0038] A method of manufacturing the printed wiring board 25
serving as an intermediate member of the LED device according to
the present invention will be described with reference to FIGS. 3A
to 3F. Although FIGS. 3A to 3F show only one LED device for
descriptive convenience, actually, a plurality of LED devices are
arranged in a matrix.
[0039] FIG. 3A shows a double-side copper-clad board 15 obtained by
adhering copper foils 17 to the two surfaces of an insulating
substrate 16. The double-side copper-clad board 15 is subjected to
boring with a drill to form a first through hole 18 and third
through holes 19 which intervene between the first through hole 18,
as shown in FIG. 3B. A diameter R2 of the first through hole 18 is
slightly larger than an outer diameter (an outer diameter added
with the thickness of the land 2) R1 at the upper end of the space
10 formed above the land 2 of the reflecting plate 1 (described
above).
[0040] Subsequently, the double-side copper-clad board 15 is
subjected to panel plating by electrolytic copper plating to form a
plating film 20 to cover the two surfaces of the insulating
substrate 16 and the hole walls of the first and second through
holes 18 and 19, as shown in FIG. 3C. Furthermore, a circuit is
formed by etching, as shown in FIG. 3D, to form a land placing
portion 21, where the land 2 described above is to be placed, at
the upper edge of the first through hole 18. Terminal portions 22
for wire bonding are formed at portions away from the land placing
portion 21.
[0041] In FIG. 3E, a solder resist 23 is applied to an unnecessary
circuit. Then, as shown in FIG. 3F, the land placing portion 21 and
terminal portions 22 are subjected to noble metal plating using
nickel and gold to form the printed wiring board 25.
[0042] A method of manufacturing the LED device using the printed
wiring board 25 formed in this manner and the LED reflecting plate
1 described above will be described with reference to FIGS. 4A to
4D.
[0043] Referring to FIG. 4A, a cream solder is applied to the land
placing portion 21 of the printed wiring board 25. After that,
positioning pins (neither is shown) are inserted in the positioning
holes 11 of the printed wiring board 25 and the positioning holes
of the printed wiring board 25 to place the LED reflecting plate 1
on the printed wiring board 25 such that the lands 2 of the LED
reflecting plate 1 are respectively fitted in the plurality of
first through holes 18 of the printed wiring board 25. In this
state, the printed wiring board 25 and LED reflecting plate 1 are
heated in a heating furnace to fuse the cream solder again, so that
the flange 9 of each land 2 is bonded on the land placing portion
21 of the printed wiring board 25 and that the LED reflecting plate
1 is bonded on the printed wiring board 25, as shown in FIG.
4B.
[0044] Subsequently, as shown in FIG. 4C, the LED chip 27 is bonded
on the LED chip mounting portion 7 of the LED reflecting plate 1 by
die bonding, and thin metal wires (wires) 28 of the LED chip 27 are
electrically connected to the terminal portions 22 of the printed
wiring board 25 by wire bonding. As shown in FIG. 4D, the land 2 of
the LED reflecting plate 1 and the terminal portions 22 of the
printed wiring board 25 are resin-sealed with a transparent molding
resin 29. As shown in FIG. 2A, lines C1 which are parallel to the
first and second bridging portions 3 and 5 and connect the third
through holes 19, lines C2 which are perpendicular to the lines C1
and cross the first bridging portions 3, and lines C3 which cross
the second bridging portions 5 are cut by dicing. Thus, LED devices
30 each forming one unit as shown in FIGS. 5A and 5B are
formed.
[0045] A heat sink 31 serving as a cooling member which cools the
land 2 of the LED reflecting plate 1 is attached to the bottom of
the LED device 30. As the height T1 of the space 10 of the land 2
is slightly larger than the thickness T2 of the printed wiring
board 25, the bottom of the recess of the land 2 comes into contact
with the heat sink 31. Thus, heat generated by the LED chip 27 is
dissipated from the land 2 outside the LED device 30 through the
heat sink 31. At this time, as the land 2 on which the LED chip 27
is mounted is formed of the metal plate, the land 2 can be formed
to have a predetermined thickness or more and uniformly, to improve
heat radiation properties.
[0046] In this embodiment, one plating process by masking the
printed wiring board 25 suffices. Therefore, when compared to a
conventional example that requires plating twice by masking in
order to form a reflecting portion and the remaining portions with
different plating films, the manufacturing cost can be decreased.
Since only a mold to form the LED reflecting plate 1 must be
prepared, the cost required by the mold can be decreased.
[0047] In the LED device 30 described above, cutting at the lines
C1, C2, and C3 forms the LED device 30 as one unit. When a
plurality of LED chips 27 are to be used as an aggregation as in a
display device or illumination device, the printed wiring board 25
need not be cut, but may be used with the plurality of LED
reflecting plates 1 being mounted on it.
[0048] A case will be described with reference to FIG. 6 wherein
the printed wiring board 25 is formed to be larger than the LED
reflecting plate 1. As the LED reflecting plate 1 is formed of a
very thin metal plate, from the viewpoint of the strength, there is
a limit to forming the LED reflecting plate 1 to have a large outer
size. For this reason, the printed wiring board 25 may be formed to
have a larger outer size than that of the LED reflecting plate 1.
In this case, if a plurality of LED reflecting plates 1 are arrayed
in a matrix, the outer size of the plurality of LED reflecting
plates 1 as a whole can be set to coincide with the outer size of
the large printed wiring board 25.
[0049] In this case, LED devices 30 each serving as one unit may be
formed by cutting. Alternatively, the printed wiring board 25 need
not be cut, but may be used with the plurality of LED reflecting
plates 1 being mounted on it. In the latter case, an LED device
which is suitably employed in a display device, illumination
device, or the like which requires high luminance can be provided.
The array of the LED reflecting plates 1 is not limited to the
matrix described above to match the outer shape of the printed
wiring board 25, but may be a horizontal array or vertical
array.
[0050] The second embodiment of the present invention will be
described with reference to FIG. 7.
[0051] An LED reflecting plate 40 shown in FIG. 7 is different from
the first embodiment described above in that a land group 6
comprising three lands 2 which are linearly connected in series
through first bridging portions 3 comprises only one group. With
this arrangement, the array of first through holes 18 formed in a
printed wiring board 25 can also cope with arrays other than 4
arrays or 4.times.n (n is an integer) arrays, unlike the first
embodiment described above.
[0052] The third embodiment of the present invention will be
described with reference to FIG. 8.
[0053] An LED reflecting plate 50 shown in FIG. 8 is characterized
in that lands 2 are not formed in a matrix but are in a staggered
manner. With this arrangement, the density of the lands 2 can be
increased. Therefore, an LED device which is suitably employed in a
display device, illumination device, or the like which requires
high luminance and uses LED devices as an aggregate can be
provided.
[0054] The fourth embodiment of the present invention will be
described with reference to FIG. 9.
[0055] This embodiment is characteristic in that an LED chip
mounting portion 7 of a land 2 is square and that a space 10 is
frustopyramidal, as shown in FIG. 9. In this arrangement, an LED
chip having a square section is mounted on the LED chip mounting
portion 7 of the land 2, so that the LED chip mounting portion 7
can be formed relatively small.
[0056] Although the first bridging portions 3 and second bridging
portions 5 are arranged on one straight line in the embodiments
descried above, they need not always be arranged on one straight
line. It suffices as far as the lands 2, and the lands 2 and frame
4 are connected integrally.
[0057] The fifth embodiment of the present invention will be
described with reference to FIGS. 10A and 10B.
[0058] An LED device 80 shown in FIGS. 10A and 10B is characterized
in that a plurality of LED chips 27A to 27D are mounted in the
recess of each land 2 of an LED reflecting plate and that the land
2 is arranged in a printed wiring board 75 and integrated with it.
This arrangement will be described in more detail.
[0059] The printed wiring board 75 has a lower-layer substrate 75A
serving as the first substrate and an upper-layer substrate 75B
serving as the second substrate. Both the lower-layer substrate 75A
and upper-layer substrate 75B are formed of insulating substrates.
A first through hole 68A to fit with the recess of the land 2 is
formed in the lower-layer substrate 75A. A second through hole 68B
from which thin metal wires 28 to be connected to the LED chips 27A
to 27D on the land 2 are extended is formed in the upper-layer
substrate 75B. The first through hole 68A and second through hole
68B have the same shape and the same size to form one through
hole.
[0060] With the recess of the land 2 being fitted in the first
through hole 68A, the upper surface of the lower-layer substrate
75A is bonded to the lower surface of the upper-layer substrate
75B. This forms a structure in which the land 2 is incorporated in
the printed wiring board 75.
[0061] On the upper surface of the upper-layer substrate 75B, a
plurality of terminal portions 72 are formed around the second
through hole 68B. Two terminal portions 72 correspond to each one
of the LED chips 27A to 27D to be mounted on the land 2. Of the two
terminal portions 72, one is a positive terminal and the other is a
negative terminal. Two thin metal wires 28 are connected to each
one of the LED chips 27A to 27D. The thin metal wires 28 are
extended from the second through hole 68B. Of the two thin metal
wires 28, one is electrically connected to the positive terminal
portion 72, and the other is connected to the negative terminal
portion 72.
[0062] Side-surface terminal portions 72A are formed on the side
surfaces of the upper-layer substrate 75B and lower-layer substrate
75A that are bonded to each other. Lower-surface terminal portions
72B are formed on the lower surface of the lower-layer substrate
75A. The terminal portions 72A and 72B are electrically connected
to the terminal portions 72. The terminal portions 72 and
lower-surface terminal portions 72B are formed by etching copper
foils adhered to the upper and lower surfaces of the upper- and
lower-layer substrates 75B and 75A, respectively. The side-surface
terminal portions 72A are formed of plating films in the third
through holes that extend through the substrates 75A and 75B. The
plurality of third through holes are formed, around the first and
second through holes 68A and 68B, along the lines C1, C2, and C3
shown in FIG. 2A.
[0063] A space 10 surrounded by an LED chip mounting portion 7 and
reflecting portion 8 of the land 2 is resin-molded with a
transparent molding resin 29. A dome-like lens 81 is arranged on
the upper-layer substrate 75B.
[0064] To form the LED device 80 which forms one unit as shown in
FIGS. 10A and 10B, a plurality of LED devices arranged in a matrix
may be cut along the lines C1, C2, and C3 shown in FIG. 2A, in the
same manner as in the first embodiment. When LED devices are to be
used as an aggregate, they need not be cut.
[0065] According to this embodiment, to bond the lower-layer
substrate 75A to the upper-layer substrate 75B, a material to form
the lower-layer substrate 75A and a material for the upper-layer
substrate 75B may be adhered, heated, and hardened. At this time,
as the recess of the land 2 is fitted in the first through hole
68A, the upper surface of the lower-layer substrate 75A and the
lower surface of the upper-layer substrate 75B sandwich a flange 9
of the land 2. Therefore, according to this embodiment, bonding
with an adhesive or by welding is not necessary to bond the land 2
to the printed wiring board 75.
[0066] Each terminal portion 72 on the printed wiring board 75 has
a thickness of about several ten .mu.m, whereas the flange 9 has a
thickness of about several hundred .mu.m. If the land 2 appears on
the surface of the printed wiring board 25, as in the first
embodiment, the entire LED device 30 becomes thicker by an amount
corresponding to the thickness of the flange 9. In contrast to
this, according to this embodiment, since the land 2 is arranged in
the printed wiring board 75 and does not appear on the surface of
the printed wiring board 75, the LED device 80 can be made thinner
than in the first embodiment.
[0067] If the flange 9 of the land 2 and the terminal portions 22
are arranged on the surface of one printed wiring board 25, as in
the first embodiment, the flange 9 of the land 2 and the terminal
portions 22 must be set apart by a sufficient distance between them
so they will not come into contact with each other. In contrast to
this, according to this embodiment, the flange 9 of the land 2 and
the terminal portions 22 are arranged on the different layers of
the printed wiring board 75. Thus, the area of the LED device 80
can be decreased when compared to the first embodiment.
[0068] In the LED device 90 described above, the plurality of LED
chips 27A to 27D are mounted on one land 2. Alternatively, one LED
chip may be mounted on one land 2.
[0069] The sixth embodiment of the present invention will be
described with reference to FIG. 11.
[0070] An LED device 90 shown in FIG. 11 is characterized in that
power is supplied to an LED chip 27E mounted on a land 2 via one
thin metal wire 28 and the land 2 made of a metal. The LED chip 27E
is connected to terminal portions 72 on an upper-layer substrate
75C through the thin metal wires 28. This arrangement is the same
as that of the fifth embodiment described above.
[0071] In the LED device 90, an electrical connection hole 91 is
formed in that portion of the land 2 of the upper-layer substrate
75C which is above a flange 9. A plating film 92 is formed on the
hole wall of the electrical connection hole 91. An interconnection
93 which extends from the electrical connection hole 91 to the
corresponding terminal portion 72 is formed on the upper surface of
the upper-layer substrate 75C. Thus, the LED chip 27E is
electrically connected to the terminal portion 72 through the metal
land 2, plating film 92 in the electrical connection hole 91, and
the interconnection 93 on the upper-layer substrate 75C.
[0072] For example, the electrical connection hole 91 and plating
film 92 can be formed in the following manner. First, a lower-layer
substrate 75A is bonded to an upper-layer substrate 75C, and the
electrical connection hole 91 is formed by boring with a drill or a
laser. After that, panel plating with electrolytic copper plating
is performed to form the plating film 92 on the hole wall of the
electrical connection hole 91.
[0073] In this embodiment, a plurality of LED chips may be mounted
on one land 2, in the same manner as in the fifth embodiment.
* * * * *