Information
-
Patent Grant
-
6740903
-
Patent Number
6,740,903
-
Date Filed
Friday, April 11, 200321 years ago
-
Date Issued
Tuesday, May 25, 200420 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Toan; Minhloan
- Greene; Pershelle
Agents
- Dennison, Schultz, Dougherty & MacDonald
-
CPC
-
US Classifications
Field of Search
US
- 257 678
- 257 688
- 257 80
- 257 81
- 257 99
-
International Classifications
-
Abstract
A substrate has a pair of metal bases, and a first heat insulation layer disposed between the metal bases. A second heat insulation layer is securely mounted on the metal bases, and a pair of circuit patterns are securely mounted on the second heat insulation layer for mounting an LED.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a substrate for a light emitting diode (LED) used in an electronic instrument such as a portable telephone.
In recent years, it is required that the substrate for the LED has a high heat radiation property, heat-resistant property and high mechanical strength in accordance with the tendencies of a high performance, multifunction, small size of the electronic instrument.
FIG. 15
is a perspective view showing a conventional substrate for an LED. The substrate comprises a metal base
51
made of copper or aluminum, an insulation layer
52
of prepreg adhered on the metal base
51
, circuit patterns
53
and
54
made of copper foil on which gold is plated. An LED
70
is mounted on the circuit pattern
53
and connected to the circuit pattern
54
by a wire
71
.
The metal base
51
has a high heat radiation property.
FIG. 16
is a perspective view of another conventional double face substrate. The substrate comprises a pair of metal bases
61
made of copper, an insulation member
63
between the metal bases
61
, insulation layers
62
of prepreg adhered to both sides of the metal bases
61
, circuit patterns
64
a
and
64
b
made of copper foil on which gold is plated. An LED
72
is mounted on the circuit pattern
64
a
and connected to the circuit pattern
64
b
by a wire.
In the substrate of
FIG. 15
, circuit patterns can not be provided on the underside of the metal base
51
. In the substrate of
FIG. 16
, since the insulation layer
62
is provided on the underside of the metal bases
61
, the heat radiation property is insufficient.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a substrate having a high heat radiation property.
According to the present invention, there is provided a substrate comprising a pair of metal bases, a first heat insulation layer disposed between the metal bases, a second heat insulation layer securely mounted on the metal bases, and mounting means for mounting an LED on the substrate.
The mounting means comprises a pair of circuit patterns securely mounted on the second heat insulation layer, the LED is securely mounted on both the circuit patterns.
In another aspect, the mounting means comprises a hole formed in the second heat insulation layer to expose surfaces of metal bases, the LED is securely mounted on both the metal bases.
The substrate further comprises upper and lower electrodes provided on an upper surface of the circuit patterns and on undersides of the metal bases.
One of the metal bases is different from the other metal base in size of a sectional shape.
These and other objects and features of the present invention will become more apparent from the following detailed description with reference to the accompanying drawings.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1
is a perspective view of a substrate according to a first embodiment of the present invention;
FIGS. 2 and 3
are perspective views showing a preparation of metal bases;
FIGS. 4 through 9
are perspective views showing a method for manufacturing the substrate;
FIG. 10
is a perspective view showing a substrate according to a second embodiment;
FIGS. 11 through 13
are perspective views showing a manufacturing method of the substrate of the second embodiment;
FIG. 14
is a perspective view showing a substrate according to a third embodiment;
FIG. 15
is a perspective view showing a conventional substrate for an LED; and
FIG. 16
is a perspective view showing another substrate.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1
is a perspective view of a substrate according to a first embodiment of the present invention.
The substrate comprises a pair of metal bases
1
a
and
1
b
made of copper, each having a cubic shape, a first heat insulation layer
2
of prepreg between the metal bases
1
a
and
1
b
, a second heat insulation layer
3
of prepreg adhered to the metal bases
1
a
and
1
b
, a pair of circuit patterns
4
a
and
4
b
made of copper foil provided on the second insulation layer
3
. On the circuit patterns
4
a
and
4
b
, electrodes
6
a
are formed by gold plating, and terminal electrodes
1
b
are formed on the underside of metal bases. An LED
40
is securely mounted on both the circuit patterns
4
a
and
4
b.
The LED
40
on the circuit patterns
4
a
and
4
b
is connected to the terminal electrodes
6
b
by through holes
5
passing through the metal bases
1
a
and
1
b.
Dimensions of the substrate, for example, are as shown in FIG.
1
.
Since the metal base is made of copper having a high heat conductivity, and there is not provided a heat insulation layer on the underside of the metal base, the substrate is excellent in heat radiation property. Therefore, an LED device using the substrate is properly used in the LED requiring a high current.
FIGS. 2 and 3
are perspective views showing a preparation of metal bases. A plurality of metal base aggregations
101
and first heat insulation layer aggregations
102
are prepared. As shown in
FIG. 3
, a pair of metal base aggregations
101
and the insulation layer aggregation are adhered by heat compression, thereby providing a set plate
105
.
Referring to
FIG. 4
, a plurality of set plates
105
are arranged between guide plates
106
, interposing a gap
105
a
between adjacent set plates
105
. Next, the set plates
105
and guide plates
106
are cut along cutting lines
107
, so that a set plate aggregation
108
is provided as shown in FIG.
5
.
Referring to
FIG. 6
, a second heat insulation layer aggregation
103
and a circuit pattern layer aggregation
104
are mounted on the set plate aggregation
108
and adhered by heat compression to form an aggregation
109
.
Next, as shown in
FIG. 7
, the circuit pattern layer aggregation
104
is cut by etching to form a plurality of grooves
104
a
, thereby separating the aggregation
104
into first and second circuit pattern aggregations
104
F and
104
S. Further, the aggregation
104
is cut to form grooves
104
b
corresponding to the gaps
105
a
. In addition, a plurality of through holes
5
are formed in both aggregations
104
F and
104
S.
As shown in
FIG. 8
, the substrate of the aggregation
109
is covered by gold plating to form electrodes
6
a
and
6
b
. At that time, the gold enters through holes to connect the upper and lower electrodes
6
a
and
6
b.
Finally, as shown in
FIG. 9
, the guide plates
106
are cut off, and the aggregation
109
is separated into unit substrates.
FIG. 10
is a perspective view showing a substrate according to a second embodiment.
The substrate comprises a pair of metal bases
11
a
and
11
b
made of copper, a first heat insulation layer
12
of prepreg between the metal bases
11
a
and
11
b
, a second heat insulation layer
13
of prepreg adhered to the metal bases
11
a
and
11
b
. The insulation layer
13
has a central hole
13
a
. An LED
20
is mounted on both the metal bases
11
a
and
11
b
in the central hole
13
a.
Since the LED
20
is directly mounted on the metal bases
11
a
and
11
b
, the heat radiation property is high.
The manufacturing method is the same as the steps of
FIGS. 2 through 5
of the first embodiment.
Referring to
FIG. 11
, a second heat insulation layer aggregation
203
having a plurality of central holes
13
a
is mounted on the set plate aggregation
108
and adhered by heat compression to form an aggregation
209
.
Next, as shown in
FIG. 12
, the second heat insulation layer aggregation
203
is cut at the gap
105
a
by cutting to form a plurality of grooves, thereby separating the aggregation
203
.
As shown in
FIG. 13
, the guide plates
106
are cut off, and the aggregation
209
is separated into unit substrates.
FIG. 14
is a perspective view showing a substrate according to a third embodiment of the present invention.
The substrate comprises a pair of metal bases
30
a
and
30
b
made of copper, a first heat insulation layer
31
of prepreg between the metal bases
30
a
and
30
b
, a second heat insulation layer
32
of prepreg adhered to the metal bases
30
a
and
30
b
, a pair of circuit patterns
33
a
and
33
b
made of copper foil provided on the second insulation layer
32
. An LED
35
is mounted on both the circuit patterns
33
a
and
33
b.
The LED
35
on the circuit patterns
33
a
and
33
b
is connected to the metal bases
30
a
and
30
b
by through holes
36
.
In the substrate of the third embodiment, the sizes of the metal bases
30
a
and
30
b
are different in sectional shape, thereby deflecting the position of the first heat insulation layer from the center line.
The coefficient of the thermal expansion of the first heat insulation layer
31
in the thickness direction is high, so that the positions of the metal bases
30
a
and
30
b
are deflected, which may generate stress in the LED
35
.
However, since the thermal expansion coefficient of the second heat insulation layer
32
in the plane direction is small, the metal bases are prevented from deflecting, thereby preventing the generation of the stress in the LED.
Furthermore, since the first heat insulation layer
31
is eccentric, the influence of thermal expansion of the first heat insulation layer is reduced.
In accordance with the present invention, a substrate is excellent in heat radiation performance.
While the invention has been described in conjunction with preferred specific embodiment thereof, it will be understood that this description is intended to illustrate and not limit the scope of the invention, which is defined by the following claims.
Claims
- 1. A substrate comprising:a pair of adjacent metal bases having a first, upper surface and a second, lower surface; a first heat insulation layer disposed between the metal bases; a second heat insulation layer securely mounted on the metal bases; a pair of circuit patterns securely mounted on the second heat insulation layer; and an LED mounted on both the circuit patterns, and an upper electrode provided on the upper surface of the circuit patterns, and a lower electrode provided on the second, lower surface of the adjacent metal bases.
- 2. The substrate according to claim 1, wherein each of the circuit patterns is electrically connected with the metal base by a through hole.
- 3. The substrate according to claim 1, wherein one of the metal bases is different from the other metal base in size of a sectional shape.
- 4. A substrate comprising:a pair of metal bases; a first heat insulation layer disposed between the metal bases; a second heat insulation layer securely mounted on the metal bases; a hole formed in the second heat insulation layer so as to expose upper surfaces of the metal bases; and an LED mounted on the exposed surfaces of the metal bases.
- 5. A substrate comprising:a pair of adjacent metal bases having a first, upper surface and a second, lower surface; a first heat insulation layer disposed between the adjacent metal bases; a second heat insulation layer securely mounted on the first, upper surface the metal bases; a pair of circuit patterns securely mounted on the second heat insulation layer; and an LED mounted on both the circuit patterns; the second, lower surface of the adjacent metal bases being exposed.
- 6. The substrate according to claim 5, wherein each of the circuit patterns is electrically connected with the metal base by a through hole.
- 7. The substrate according to claim 5, wherein one of the metal bases is different from the other metal base in size of a sectional shape.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2002-112645 |
Apr 2002 |
JP |
|
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Number |
Name |
Date |
Kind |
5298768 |
Okazaki et al. |
Mar 1994 |
A |
5475241 |
Harrah et al. |
Dec 1995 |
A |
6093940 |
Ishinaga et al. |
Jul 2000 |
A |
20020139990 |
Suehiro et al. |
Oct 2002 |
A1 |