JP2006339224A - Substrate for led and led package - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate for LED excellent in heat dissipation property and simple in manufacture, and further to provide an LED package using the substrate for LED. <P>SOLUTION: The substrate (1) for LED includes an insulating layer (11), through which an LED mounting hole (14) is made, joined with a flat surface of a heat dissipation part (10), and by a wiring (12) provided on the insulating layer (11) and having a wiring pattern. In the LED package (2) of the LED mounting hole (14) of the substrate (1) for LED, an LED chip (20) is mounted on the heat dissipation part (10), and the LED chip (10) is electrically connected with a wiring part (12). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an LED substrate, in particular, an LED substrate excellent in heat dissipation, and an LED package using the LED substrate.

  Conventionally, an LED package using an LED chip has been proposed as shown in FIG. 3A. This LED package (30) has an LED chip (20) mounted on a substrate (34) in which a wiring portion (wiring pattern) (33) made of an insulating layer (32) and copper foil is laminated on the surface of a metal substrate (31). The LED chip (20) is mounted and electrically connected to the wiring part (33) via the bonding wire (21). A thermal conductive metal such as aluminum is used as the metal substrate (32), and a glass epoxy sheet or the like is used as the insulating layer (32). As the LED chip (20), for example, a sapphire substrate having a gallium nitride-based light emitting portion formed thereon is used.

  An LED package in which an LED chip is bonded to a ceramic substrate with an acrylic adhesive has also been proposed (see Patent Document 1).

  Further, the above-described LED package has a structure in which a reflecting portion and a frame are provided around the LED chip in order to efficiently extract the light from the LED chip to the front side. For example, the LED package (30) shown in FIG. 3A shows a structure in which a reflective member (35) opened conically around the LED chip (20) is bonded.

  FIG. 3B shows another conventional LED package (40). The LED package (40) is formed by punching a substrate (34) in which a metal substrate (31), an insulating layer (32), and a wiring portion (33) are stacked, and forming a recess in the bottom of the recess (36). The chip (20) is mounted, and the heat dissipation is improved by directly mounting the LED chip (20) on the metal plate (31) (see Patent Document 2).

Further, as shown in FIG. 3C, in the LED package (41) of the type in which the LED chip is directly mounted on the metal plate, a protrusion (43) is provided on the metal substrate (42), and a recess ( It is proposed that the LED chip (20) is mounted on the bottom of the recess (44) and the protruding portion (43) is used as a reflecting portion. In FIG. 3C, (32) is an insulating layer, (33) is a wiring part, and (45) is a resin sealing part. (See Patent Document 3).
JP 2004-296792 A JP 2000-353827 A JP 2003-152225 A

  By the way, since recent LED chips generate a large amount of heat, higher heat dissipation is required. However, in the LED package (30) in which the LED chip (20) is mounted on the insulating layer (32) in FIG. 3A or the LED package in which the LED chip is bonded to the ceramic substrate with an acrylic adhesive, The heat dissipation was insufficient.

  In addition, in the LED package (40) of FIG. 3B, the heat dissipation is improved by mounting the LED chip (20) on the metal substrate (31) without the insulating layer (32), but it is emitted to the side. There is a problem that the reflected light is not efficiently extracted forward and the reflection efficiency is lowered.

  Further, in the LED package (41) of FIG. 3C, in order to form the protrusions (43) and the recesses (44) on the metal substrate (42), complicated processing is required, which causes a problem in productivity. In addition, when processing for forming the recesses (36) and (44) is performed, the surface smoothness of the processed surface is deteriorated, and the bonding property to the LED chip (20) may be deteriorated.

  In view of the above-described technical background, an object of the present invention is to provide an LED substrate that has excellent heat dissipation and can be manufactured by a simple process, and an LED package using the LED substrate.

  That is, the LED substrate of the present invention has the configuration described in [1] to [5] below.

  [1] An LED substrate, wherein an insulating layer having an LED mounting hole is bonded to a flat surface of a heat radiation portion, and a wiring portion constituting a wiring pattern is provided on the insulating layer.

  [2] The LED substrate according to [1], wherein the heat dissipating part is a metal plate or a heat sink.

  [3] The LED substrate according to [1] or [2], wherein a reflective portion is provided around the LED mounting hole.

  [4] The LED substrate according to any one of items 1 to 3, wherein a total thickness of the insulating layer and the wiring portion is smaller than a height of the LED chip.

  [5] The LED substrate according to any one of [1] to [4], wherein the insulating layer is a glass epoxy sheet obtained by impregnating a glass cloth with an epoxy resin.

  Moreover, the manufacturing method of the board | substrate for LED of this invention has the structure as described in following [6] [7].

  [6] A wiring board manufacturing process for manufacturing a wiring board by bonding a wiring portion constituting a wiring pattern on one side of a sheet-like insulating layer, a perforating process for drilling an LED mounting hole in the wiring board, and heat dissipation And a bonding step of bonding the other surface side of the wiring board to the flat surface of the part.

  [7] The method described in 6 above, wherein a three-layer wiring board is manufactured by laminating an adhesive layer on the other surface side of the insulating layer in the wiring board manufacturing process, and the wiring board is bonded to the heat radiating portion by heat pressing in the bonding process. Of manufacturing a substrate for LED.

  Furthermore, the LED package of the present invention has the following configurations [8] to [10].

  [8] In the LED substrate according to any one of 1 to 5 above, the LED chip is mounted on the heat dissipation part in the LED mounting hole, and the LED chip is electrically connected to the wiring part. LED package characterized by

  [9] The LED package according to [8], wherein an upper surface of the wiring board is lower than an upper surface of the LED chip.

  [10] The LED package according to item 8 or 9, wherein the inside of the mounting hole and the inside of the reflection portion of the wiring board are sealed with resin.

  According to the substrate for LED according to the invention of [1], the LED chip can be directly mounted on the heat radiating portion, so that the heat radiation efficiency is good. Moreover, since it is not necessary to process the heat radiation part, the manufacturing process is simple and the productivity is good.

  The LED substrate according to the invention [2] has particularly good heat dissipation efficiency.

  According to the substrate for LED concerning each invention of [3] [4], the light which LED chip radiates can be taken out efficiently ahead.

  According to the LED substrate according to the invention of [5], formation of the LED mounting hole is easy.

  [6] According to the method for manufacturing an LED substrate according to each invention of [7], the LED substrate of the present invention can be manufactured.

  [8] According to the LED package of each invention of [10], since the LED chip is directly mounted on the heat dissipation portion, the heat dissipation efficiency is good.

  According to the LED package of [9], the light emitted from the LED chip can be efficiently extracted forward.

  FIG. 1 shows an embodiment of an LED substrate (1) of the present invention, and FIG. 2 shows an embodiment of an LED package (2) using the LED substrate (1).

  The LED substrate (1) is laminated on the surface of the heat radiating part (10) made of a metal flat plate such as aluminum or copper via an insulating layer (11) and an adhesive layer (13), and wiring is formed on the insulating layer (11). A wiring part (12) made of copper foil formed in a pattern is laminated, and a resin sheet (16) is laminated and integrated on the wiring part (12). The insulating layer (11) is provided with an LED mounting hole (14), and the resin sheet (16) has a conical hole having a diameter larger than that of the LED mounting hole (14) and larger on the opening side. (17) is drilled. The conical hole (17) is fitted with an aluminum ring (18) corresponding to the inner peripheral shape of the hole and having a mirror-finished inner peripheral surface to form a reflecting portion. The heat dissipating part (10) is exposed by the LED mounting hole (14) and the conical hole (17), and the wiring part (12) is exposed around the LED mounting hole (14).

The LED substrate (1) is manufactured, for example, by the following steps.
[1] Wiring board manufacturing process A wiring part (12) having a required wiring pattern is bonded to one side of a sheet-like insulating layer (11), and an adhesive layer (13) made of hot melt adhesive is bonded to the other side. Then, a three-layer wiring board (15) is manufactured.
[2] Drilling step An LED mounting hole (14) is drilled at the LED mounting planned position of the wiring board (15).
[3] Reflector manufacturing process A conical hole (17) is formed in the resin sheet (16). The diameter of the conical hole (17) on the small diameter side (side joined to the wiring board) is larger than the LED mounting hole (14) of the wiring board (15). Then, the ring (18) is inserted into the conical hole (17).
[4] Joining Step On the heat radiation part (10), the wiring board (15) and the resin sheet (16) are overlapped with the positions of the LED mounting holes (14) and the conical holes (17), and hot pressed. By this heat pressing, the heat radiating part (10) and the wiring board (15), the wiring board (15) and the resin sheet (15) are integrally bonded, and the adhesive layer (13), the insulating layer (11), and the insulating layer The layer (11) and the wiring part (12) are also more firmly joined to form the LED substrate (1).

  In the LED substrate (1) described above, the heat radiating section (10) has a good thermal conductivity and has a flat surface with no irregularities on the surface to which the wiring board (15) is joined. For example, a metal plate having high thermal conductivity such as aluminum or copper, or a heat sink made of these metals can be recommended. Examples of the heat sink include a plate in which a large number of fins are erected on a flat plate, a toe pipe enclosing a working fluid, a cooler for circulating a coolant inside, and the like. All of these have excellent heat dissipation and can efficiently dissipate the heat generated by the LED chip (20). It is also preferable to form an anodized film on the surface of the heat radiating portion (10) in order to improve the adhesive force between the heat radiating portion (10) and the adhesive layer (13). The adhesive constituting the adhesive layer (13) enters the pores of the anodized film, and a high adhesive force due to the anchor effect can be obtained. The kind of film is not limited, and any film or the like can be used as appropriate. The thickness of such an anodized film is preferably 0.1 to 5 μm.

  The material of the insulating layer (11) is not limited, and any known material such as resin or ceramic can be used. A particularly recommended material is a glass epoxy sheet in which a glass cloth is impregnated with an epoxy resin. The glass epoxy sheet has excellent electrical and mechanical properties and is flexible, and can be easily drilled without being broken when the mounting hole (14) is punched. In addition, the insulating layer (11) does not need to be present in the entire area of the heat radiating portion (10). .

  The material of the wiring part (12) is not limited, and any known material such as copper or aluminum can be arbitrarily used.

  The material of the adhesive layer (13) is not limited as long as it can be bonded to both the heat dissipating part (10) and the insulating layer (11). As described above, it may be bonded to the heat radiating part (10) by hot pressing using a hot melt adhesive such as an epoxy resin, or may be attached to the heat radiating part (10) using a sticky adhesive. .

  In order to efficiently extract the light from the LED chip (20) forward (upward in the drawing), the thickness of the wiring board (15) is preferably smaller than the LED chip (20) to be attached. A particularly preferable thickness of the wiring board (15) is 2/3 or less of the height of the LED chip. In general, in the LED chip (20), light is mainly emitted from the upper surface, and a part is also emitted from the upper side surface. Therefore, if the thickness of the wiring board (15) is made smaller than the height of the LED chip (20) and the upper surface of the wiring board (15) is made lower than the upper surface of the LED chip (20), the light is efficiently Can be taken forward. Further, if the thickness of the wiring board (15) is 2/3 or less of that of the LED chip (20), the light emitted to the side can be surely reflected by the reflecting portion and taken out forward.

  In addition, the reflecting portion illustrated in FIG. 2 has a mirror-finished aluminum ring (18) inserted into the conical hole (17) of the resin sheet (16), but the surface is processed into a mirror surface. It is not limited to aluminum. Further, instead of the ring (18), the reflection film may be formed by plating the wall surface of the conical hole (17) with silver or the like. In addition, as described above, the heat sink (10), the wiring board (15), and the resin sheet (16) are stacked and bonded together by hot pressing, and the heat sink (10) The resin sheet (16) may be joined separately after joining the wiring board (15). Furthermore, you may attach the ring-shaped reflection member (35) illustrated to FIG. 3B, without using a resin sheet.

  In addition, the board | substrate for LED of this invention does not limit a manufacturing method to the process mentioned above. For example, a wiring board having a two-layer structure of an insulating layer and a wiring part may be manufactured, and this wiring board may be joined to the heat dissipation part with an adhesive, or all members may be joined in one step.

  In the LED package (2) of FIG. 2, the LED chip (20) is mounted on the bottom of the LED mounting hole (14) of the LED substrate (1), that is, the heat dissipating part (10). It is electrically connected to the wiring part (13) via the bonding wire (21). The LED mounting hole (14) of the wiring board (15) and the conical hole (17) of the resin sheet (16) are filled with resin (19) and sealed. For example, silver paste is used for bonding the LED chip (20), and acrylic resin, epoxy resin, silicon resin, or the like is used as the sealing resin. The type of the LED chip (20) is not limited at all, and any LED chip can be used. For example, an LED chip in which a gallium nitride-based light emitting portion is formed on a sapphire substrate can be listed.

  In the LED package (2), since the LED chip (20) is directly mounted on the heat radiating part (10) without an insulating layer interposed therebetween, the heat generated in the LED chip (20) is quickly radiated from the heat radiating part (10). The heat is absorbed and released. Since the LED substrate (1) is obtained by joining the wiring board (15) without processing the flat surface of the heat radiating section (10), the manufacturing process is simple and the productivity is good. Moreover, since the process for forming a recessed part and a protrusion part in a heat radiating part (10) is unnecessary, various existing heat radiating parts can be utilized as they are, and the joining property of LED chip is also good. Moreover, the light can be efficiently extracted forward by forming the wiring board (15) thinner than the LED chip (20).

  Based on the above-described steps [1] to [4], the LED substrate (1) shown in FIG. 1 was manufactured.

As the heat radiating portion (10), an aluminum flat plate made of a 6000 series alloy having high thermal conductivity and having a thickness of 1 mm was used, and an anodic oxide film having a thickness of 0.1 μm was formed on the surface. Further, a glass epoxy sheet having a thickness of 0.1 mm is used as the insulating layer (11), a copper foil having a thickness of 0.018 mm is used as the wiring portion (12), and an epoxy resin sheet having a thickness of 0.04 mm is used as the adhesive layer (13). It was.
[1] Wiring board manufacturing process The wiring portion (12) of the wiring pattern is bonded to one surface side of the insulating layer (11), and the bonding layer (13) is bonded to the other surface side. A 158 mm wiring board (15) was produced.
[2] Drilling Step An LED mounting hole (14) having a diameter of 2.5 mm was drilled at a required position of the wiring board (15).
[3] Reflector manufacturing process A conical hole (17) having a diameter of 4 mm on the small diameter side and a diameter of 6 mm on the large diameter side is drilled in the resin sheet (16), and the inner peripheral surface of the conical hole (17) is mirror-finished aluminum. A ring (18) made was inserted.
[4] Joining process On the heat radiating part (10), the wiring board (15) and the resin sheet (16) are overlapped with the positions of the LED mounting holes (14) and the conical holes (17), and these are hot-pressed. Then, they were integrally bonded to obtain an LED substrate (1).

  Further, an LED package (2) shown in FIG. 2 was manufactured using the LED substrate (1) manufactured in the above process.

  In the LED mounting hole (14) of the LED substrate (1), a square LED chip (20) of 1 mm × 1 mm × height 0.3 mm was joined to the heat radiating part (10) using silver paste. The thickness of the silver paste was 0.1 mm, and the height from the upper surface of the heat dissipating part (10) to the upper surface of the LED chip (20) was 0.4 mm. Accordingly, the thickness (0.158 mm) of the wiring board (15) is substantially about 40% of the LED chip (20). Next, the LED chip (20) and the wiring part (12) were electrically connected by a bonding wire (21). The LED mounting hole (14) and the conical hole (17) were filled with silicon resin as a sealing resin (19) to obtain an LED package (2).

  Furthermore, using the same material, the LED substrate (3) of the present invention structure (FIG. 4A) for attaching the LED chip directly to the heat dissipation part, and the LED substrate (4) (FIG. 4B) of the conventional structure attached on the insulating layer Produced and heat dissipation performance comparison test.

  LED chip (20) 1mm x 1mm x height 0.3mm, square LED chip with 1W output, heat dissipation part (10) made of 6000 series alloy, 10mm x 10mm x 1mm thickness aluminum flat plate, insulating layer (11) 0.08 mm thick glass epoxy sheet, 0.035 mm thick copper foil as the wiring part (12), and 0.04 mm thick epoxy resin sheet as the adhesive layer (13). As in the above example, an anodic oxide film having a thickness of 0.1 μm was formed on the surface of the heat radiating portion (10).

  In the LED substrate (3) shown in FIG. 4A, the LED chip is placed on the heat dissipating part (10) in the LED mounting hole (14) formed in the three-layer wiring board (15) as in the above-described embodiment. (20) was mounted and connected to the wiring section (12) with a bonding wire (21). On the other hand, the LED substrate (4) shown in FIG. 4B is obtained by bonding an insulating layer (11) on a heat radiation part (10) via a bonding layer (13), and an LED chip on the insulating layer (11). (20) was mounted and connected to the wiring section (12) with a bonding wire (21).

  When the surface temperature of the substrate was measured by energizing these LED plates (3) and (4), the LED substrate (3) in FIG. 4A was 84 ° C., and the LED substrate (4) in FIG. 4B was 117 ° C. there were. From these comparisons, it was confirmed that the heat dissipation performance was improved by directly mounting the LED chip on the heat dissipation portion.

  Since the LED substrate of the present invention is excellent in heat dissipation, it can be suitably used for an LED package on which a high-brightness LED having a large heat generation amount is mounted.

It is sectional drawing which shows one Embodiment of the board | substrate for LED of this invention. It is sectional drawing which shows one Embodiment of the LED package of this invention. It is sectional drawing which shows an example of the conventional LED package. It is sectional drawing which shows the other example of the conventional LED package. It is sectional drawing which shows the other example of the conventional LED package. It is sectional drawing of the board | substrate for LED of this invention structure used for the heat dissipation performance comparison test. It is sectional drawing of the board | substrate for LED of the conventional structure used for the heat dissipation performance comparison test.

Explanation of symbols

1,3 ... LED substrate
2 ... LED package
10… Heat dissipation part
11… Insulating layer
12 ... Wiring section
13… Adhesive layer
14 ... LED mounting hole
15 ... wiring board
18 ... Ring (reflection part)
19… Sealing resin
20 ... LED chip

Claims (10)

  An LED substrate, wherein an insulating layer having an LED mounting hole is bonded to a flat surface of a heat radiating portion, and a wiring portion constituting a wiring pattern is provided on the insulating layer.   The LED substrate according to claim 1, wherein the heat dissipating part is a metal plate or a heat sink.   The LED substrate according to claim 1, wherein a reflective portion is provided around the LED mounting hole.   The LED substrate according to claim 1, wherein the total thickness of the insulating layer and the wiring portion is smaller than the height of the LED chip.   5. The LED substrate according to claim 1, wherein the insulating layer is a glass epoxy sheet in which a glass cloth is impregnated with an epoxy resin.   A wiring board manufacturing process for manufacturing a wiring board by joining a wiring part constituting a wiring pattern on one surface side of a sheet-like insulating layer, a perforating process for drilling an LED mounting hole in the wiring board, and a flat heat dissipation part And a bonding step of bonding the other surface side of the wiring board to the surface.   The LED according to claim 6, wherein an adhesive layer is laminated on the other side of the insulating layer in the wiring board manufacturing process to manufacture a three-layer wiring board, and the wiring board is bonded to the heat radiating portion by heat pressing in the bonding process. Manufacturing method for industrial use.   The LED substrate according to any one of claims 1 to 5, wherein the LED chip is mounted on the heat dissipation part in the LED mounting hole, and the LED chip is electrically connected to the wiring part. LED package.   The LED package according to claim 8, wherein an upper surface of the wiring board is lower than an upper surface of the LED chip. The LED package according to claim 8 or 9, wherein an inside of the mounting hole and the inside of the reflection portion of the wiring board are sealed with a resin.

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