JP2010283253A - Light-emitting device and substrate for light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting device for suppressing a temperature increase, and to provide a substrate for a light-emitting device. <P>SOLUTION: The light-emitting device includes a substrate 1 formed of ceramic, a light-emitting diode 3 mounted on a surface of the substrate 1, a front surface multilayer wiring pattern 2a formed on the surface of the substrate 1 and electrically connected to the light-emitting diode 3, a back surface multilayer wiring pattern 2b formed on a back surface of the substrate 1, a plurality of electric conduction vias 4a formed through the substrate 1 and electrically connecting the front surface multilayer wiring pattern 2a and the back surface multilayer wiring pattern 2b, and a plurality of thermal conduction vias 4b formed through the substrate 1 and thermally connecting the front surface multilayer wiring pattern 2a and the back surface multilayer wiring pattern 2b. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a light emitting device using a light emitting diode (LED) and a substrate for the light emitting device.

  In recent years, light emitting devices using light emitting diodes (LEDs) have attracted attention from the viewpoint of light emission efficiency and lifetime, and further efficiency and higher output are being promoted. However, it is known that the LED in such a light emitting device has a poor light emission efficiency due to a temperature rise due to heat generation during light emission, and efficiently releases the heat generated by the LED to suppress the temperature rise of the light emitting device. Is required.

  As a technique for suppressing the temperature rise of such a light emitting device, for example, Patent Document 1 is mounted on a ceramic substrate having a housing recess opened on the front surface and a bottom surface of the housing recess. A light emitting diode chip, a plurality of metal members joined to the back surface of the substrate and serving as a wiring portion, and plated through the bottom surface of the housing recess from the bottom surface of the substrate to electrically connect the light emitting diode chip and the metal member Disclosed is a technology that includes a through-hole to be connected, conducts heat generated by the light-emitting diode chip to the metal member on the back surface through the through-hole, and enhances the heat dissipation effect of the heat generated by the light-emitting diode to suppress the temperature rise of the light-emitting device. Has been.

  Patent Document 2 includes a heat sink, a substrate overlying the heat sink, a trace layer overlying the substrate, and a via extending through the substrate, and heat from a light emitting diode disposed on the substrate. A technique is disclosed in which a heat dissipation effect of heat generated by a light emitting diode is enhanced by conducting to a heat sink via a via to suppress a temperature rise of the light emitting device.

JP 2003-243718 A JP 2007-516592 A

  However, in the technique described in Patent Document 1, only two through holes for supplying power to the light-emitting diode chip from the metal member provided on the back surface of the substrate are provided, and the through holes are disposed in the housing recesses on the substrate surface. In addition, the ability to transfer heat generated from the light emitting diode chip to the metal member is not necessarily sufficient. Therefore, in such a case, there is a concern that the heat dissipation effect in the light emitting device is not sufficiently exhibited, the temperature rise around the light emitting diode chip is not sufficiently suppressed, and the light emission efficiency is lowered.

  In the technique described in Patent Document 2, vias are provided as heat transfer paths through which heat flows from the pads to which the light emitting diodes are coupled to the heat sink, but the vias are disposed near the pads provided below the light emitting diodes. The heat transmitted from the light emitting diode through the connector and the plurality of trace layers provided on the surface of the substrate is accumulated in the light emitting device, and the heat generated from the light emitting diode is not sufficiently transmitted to the heat sink. It is possible. Therefore, the heat dissipation effect in the light emitting device is not sufficiently exhibited, and the temperature rise around the light emitting diode chip is not sufficiently suppressed, and there is a concern that the light emission efficiency is lowered.

  The present invention has been made in view of the above, and an object of the present invention is to provide a light-emitting device and a substrate for a light-emitting device that can suppress a temperature rise in the light-emitting device.

  To achieve the above object, the present invention provides a substrate formed of ceramics, a light emitting diode mounted on the surface of the substrate, and formed on the surface of the substrate and electrically connected to the light emitting diode. A front surface metal wiring; a back surface metal wiring formed on the back surface of the substrate; a plurality of electrical conduction vias formed through the substrate and electrically connecting the front surface metal wiring and the back surface metal wiring; And a plurality of heat conduction vias that thermally connect the front surface metal wiring and the back surface metal wiring.

  In the present invention, the temperature rise in the light emitting device can be suppressed.

It is sectional drawing which shows typically the whole structure of the light-emitting device which concerns on the 1st Embodiment of this invention. It is a figure which shows the mode of the heat transfer in the light-emitting device which concerns on the 1st Embodiment of this invention. It is a top view which shows arrangement | positioning of the via | veer in the 1st Embodiment of this invention. It is a top view which shows arrangement | positioning of the via | veer in the 2nd Embodiment of this invention. It is a top view which shows arrangement | positioning of the via | veer in the 3rd Embodiment of this invention. It is a top view which shows arrangement | positioning of the via | veer in the 4th Embodiment of this invention. It is sectional drawing which shows the shape of the via | veer in the 5th Embodiment of this invention. It is sectional drawing which shows the shape of the via | veer in the 6th Embodiment of this invention. It is sectional drawing which shows typically the whole structure of the light-emitting device which concerns on the 7th Embodiment of this invention. It is a figure which shows the mode of the heat transfer in the light-emitting device which concerns on the 7th Embodiment of this invention. It is a top view which shows the radiation fin in the 8th Embodiment of this invention. It is sectional drawing which shows the radiation fin in the 8th Embodiment of this invention. It is sectional drawing which shows the radiation fin in the 9th Embodiment of this invention. It is sectional drawing which shows typically the whole structure of the light-emitting device which concerns on the 10th Embodiment of this invention. It is sectional drawing which shows typically the whole structure of the light-emitting device which concerns on the 11th Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
FIG. 1 is a cross-sectional view schematically showing the overall configuration of the light emitting device according to the first embodiment of the invention.

  1, a light emitting device 100 includes a substrate 1 formed of an insulating member, a surface multilayer wiring pattern 2a formed on the surface of the substrate 1 (upper surface in FIG. 1), and the back surface of the substrate 1 (FIG. 1). A plurality (for example, two) of the back surface multilayer wiring pattern 2b formed on the middle lower surface and the substrate 1 that are provided through the substrate 1 and electrically connect the front surface multilayer wiring pattern 2a and the back surface multilayer wiring pattern 2b. The electrical conduction via 4a (see FIG. 3 later), the light emitting diode 3 mounted on the surface of the substrate 1 so as to be electrically connected to the surface multilayer wiring pattern 2b, and the substrate 1 are provided. A plurality of (for example, six: see FIG. 3) thermal conduction vias 4b that thermally connect the front surface multilayer wiring pattern 2a and the back surface multilayer wiring pattern 2b are provided. The surface multilayer wiring pattern 2a has a plurality of (for example, two) regions insulated from each other, and the light emitting diode 3 is mounted so as to straddle these regions. The light emitting diode 3 mounted on the light emitting device 100 is electrically connected to a power source (not shown) through the front surface multilayer wiring pattern 2a, the electrical conduction via 4a, and the back surface multilayer wiring pattern 2b, and supplies power from the power source. Light is emitted. The thermal conduction via 4b also functions as a path for supplying power from the power source to the light emitting diode 3 like the electrical conduction via 4a.

  The material used for the substrate 1 is, for example, ceramics such as alumina, silicon carbide, aluminum nitride, or glass mainly composed of silicon dioxide. When glass mainly composed of silicon dioxide is used as the material of the substrate 1, it is preferable to use sodium oxide, magnesium oxide, calcium oxide, boron oxide, phosphorus oxide, or the like as a subcomponent. Can be suppressed, and reliability can be improved.

  A mask corresponding to microblasting is formed on the substrate 1 formed in this way, and through holes constituting the electric conduction via 4a and the heat conduction via 4b are formed from both sides of the substrate 1 by the microblasting method. Form. This microblast processing method is excellent in mass productivity because one surface of the substrate can be processed at a time, and the position of a through hole or the like can be formed with an accuracy of about ± 1 μm. After the formation of the through hole, a metal film is also formed in the through hole by forming the multilayer wiring patterns 2a and 2b from the metal film so as to include the through holes for the vias 4a and 4b using a resist or the like. The wiring pattern 2a and the back surface multilayer wiring pattern 2b are electrically and thermally connected.

  The front surface multilayer wiring pattern 2a and the back surface multilayer wiring pattern 2b are composed of a multilayer film. For example, a nickel and gold film is formed on titanium or chromium as a base film, and then, by electrolytic copper plating. A copper film is formed. The base film is formed in order to improve the adhesion between the material of the substrate 1 and gold. When a thermal load is applied to the substrate after the formation of the multilayer wiring patterns 2a and 2b, a platinum film may be formed between the base film and the gold film formed thereon.

  The electrical conduction via 4a and the thermal conduction via 4b are formed in the same manner when the multilayer wiring patterns 2a and 2b are formed. That is, each of the vias 4a and 4b is formed, for example, by forming titanium or chromium on the inner surface of the through hole using titanium or chromium as a base film, and filling the through hole by electrolytic copper plating. Thereafter, the portion of the copper that protrudes from the surface of the substrate 1 and grows is smoothed by grinding or polishing.

In consideration of the heat transfer effect and the state of internal stress, the copper film thickness in the multilayer wiring patterns 2a and 2b is, for example, about 1 μm to 100 μm. This is because the copper film thickness is related to its heat transfer effect and internal stress. For example, the amount of heat Q transmitted through a certain object is measured by measuring the heat conductivity of the object as h (W / (m · K)), the heat transfer area as A (m ² ), and the transfer time as t (h). When the temperature difference between the points is ΔT (K) and the distance between the measurement points is L (m), the following equation is obtained.

Q = (h × A × t × ΔT) / L (Formula 1)
From the above formula 1, it can be seen that the larger the transfer area A (m ² ), the more heat is transferred. That is, the multilayer wiring patterns 2a and 2b have a higher heat transfer effect as the copper film thickness increases. However, as the copper film thickness increases, the internal stress increases, and the influence on the shape of the substrate 1 increases. Therefore, the film is formed with a film thickness that has a higher electrothermal effect and has less influence on the shape of the substrate 1 by internal stress. The multilayer wiring patterns 2a and 2b can be formed to have the same thickness on both surfaces of the substrate 1, thereby canceling internal stress.

  Next, the positional relationship between the electrical conduction via 4a and the thermal conduction via 4b in the light emitting device 100 according to the present embodiment will be described with reference to the drawings. FIG. 3 is a plan view showing the arrangement of each via in the substrate 1.

  In FIG. 3, a surface multilayer wiring pattern 2 a is formed on the surface of the substrate 1. The surface multilayer wiring pattern 2a is divided into a plurality of (for example, two) regions that are electrically insulated from each other, and each region has one electrical conduction via 4a and one or more (for example, three) heat conduction. Vias 4b for use. The light emitting diode 3 is mounted so as to straddle the electrically insulated region of the surface multilayer wiring pattern 2a, and the electric conduction via 4a in each region in the multilayer wiring pattern 2a is disposed below the light emitting diode 3. Has been. That is, in the light emitting device 100, the light emitting diode 3 (see FIG. 1 and the like) is mounted so as to straddle the electric conduction via 4a in each region in the multilayer wiring pattern 2a. One or more thermal conduction vias 4b provided in each region of the multilayer wiring pattern 2a are arranged along a circumference 11 centering on the light emitting diode 3 mounted on the substrate 1 in the light emitting device 100. In other words, the heat conduction via 4 b is arranged at an equal distance from the light emitting diode 3 so as to surround the light emitting diode 3.

  In such a light emitting device 100, power is supplied from a power source (not shown) to the light emitting diode 3, and light and heat are emitted. The state of the transfer of heat released from the light emitting diode 3 at this time will be described with reference to the drawings.

  FIG. 2 is a diagram schematically showing a state of transfer of heat generated from the light emitting diode 3 in the light emitting device 100 shown in FIG.

  As shown in FIG. 2, part of the heat generated in the light emitting diode 3 is released into the atmosphere of the light emitting diode 3 as indicated by arrows 5a and 5b, and part of the heat of the substrate 1 as indicated by arrow 5c. It is transmitted to the surface multilayer wiring pattern 2a. Further, part of the heat released into the atmosphere is transmitted to the surface multilayer substrate pattern 2a of the substrate 1 as indicated by an arrow 5b. The heat transferred to the surface multilayer wiring pattern 2a is transferred to the surface of the substrate 1 through the surface multilayer wiring pattern 2a as indicated by the arrow 5d, and a part of the heat is transmitted through the electrical conduction via 4a as indicated by the arrow 5f. To the backside multilayer wiring pattern 2b, partly transmitted to the substrate 1 as indicated by the arrow 5e, and partly transmitted to the backside multilayer wiring pattern 2b via the thermal conduction via 4b as indicated by the arrow 5g. Is done. Further, part of the heat conducted to the substrate 1 is transmitted to the back surface multilayer wiring pattern 2b as indicated by an arrow 5h. Thus, the heat generated in the light emitting diode 3 is transmitted to each part of the light emitting device 100 and released into the atmosphere.

  The operation in the present embodiment configured as described above will be described.

  In the light emitting device 100, when power is supplied from a power source (not shown) to the light emitting diode 3 through the back surface multilayer wiring pattern 2b, the electrical conduction via 4a, and the front surface multilayer wiring pattern 2a, the light emitting diode 3 emits light and generates heat. . A part of the heat generated in the light emitting diode 3 is transmitted to the back surface multilayer wiring pattern 2b through the electrical conduction via 4a and released into the atmosphere of the light emitting device 100, and the other part is a surface multilayer wiring pattern. 2a and the heat conduction via 4b are transmitted to the back surface multilayer wiring pattern 2b and emitted into the atmosphere of the light emitting device 100.

  The operation and effect of the present embodiment configured as described above will be described in detail while comparing with the prior art.

  In the prior art described in Patent Document 1, only two through holes for supplying power to the light-emitting diode chip from the metal member provided on the back surface of the substrate are provided, and the through holes are disposed in the housing recesses on the substrate surface. In addition, the ability to transfer heat generated from the light emitting diode chip to the metal member is not necessarily sufficient. Therefore, in such a case, there is a concern that the heat dissipation effect in the light emitting device is not sufficiently exhibited, the temperature rise around the light emitting diode chip is not sufficiently suppressed, and the light emission efficiency is lowered. In the technique described in Patent Document 2, vias are provided as heat transfer paths through which heat flows from the pads to which the light emitting diodes are coupled to the heat sink, but the vias are disposed near the pads provided below the light emitting diodes. The heat transmitted from the light emitting diode through the connector and the plurality of trace layers provided on the surface of the substrate is accumulated in the light emitting device, and the heat generated from the light emitting diode is not sufficiently transmitted to the heat sink. It is possible. Therefore, the heat dissipation effect in the light emitting device is not sufficiently exhibited, and the temperature rise around the light emitting diode chip is not sufficiently suppressed, and there is a concern that the light emission efficiency is lowered.

  On the other hand, in the present embodiment, the substrate 1 is formed of ceramics, formed on the surface of the substrate 1 and electrically connected to the light emitting diode 3, and formed on the back surface of the substrate 1. A plurality of electrical conduction vias 4a formed through the substrate 1 and electrically connected to the front surface multilayer wiring pattern 2a and the back surface multilayer wiring pattern 2b are formed through the substrate 1. A plurality of heat conduction vias 4b that thermally connect the wiring pattern 2a and the backside multilayer wiring pattern 2b are provided, and heat from the light emitting diode 3 is transmitted through the electric conduction via 4a, the front surface multilayer wiring pattern 2a, and the heat conduction. Since it has constituted so that it may transmit via via 4b, the temperature rise in light emitting device 100 can be controlled. Accordingly, it is possible to suppress a decrease in the light emission efficiency of the light emitting diode 3.

  Moreover, in the prior art described in Patent Document 2, a glass epoxy substrate using an epoxy resin as a substrate material is shown. However, since the resin material has low thermal conductivity and heat is easily stored, the entire substrate is deformed by heat. I am worried about it. On the other hand, in this embodiment, since the substrate is formed using ceramics having a higher thermal conductivity than the resin material, it is difficult to accumulate heat from the light emitting diode 3, and it is possible to suppress deformation due to heat of the substrate. it can.

  Further, since the plurality of heat conduction vias 4b are arranged so as to be substantially equidistant from the light emitting diode 3, the heat generated in the light emitting diode 3 is transmitted to the back surface multilayer wiring pattern 2b via each heat conduction via 4b. The transmission distances until they are made are substantially equal, and the heat transfer amount in each heat conduction via 4b is less likely to be uneven, and heat can be transferred more efficiently.

  Furthermore, in the present embodiment, the electrical conduction via 4a and the thermal conduction buried via 4b formed on the substrate 1 can be formed by the same process, and thus an increase in manufacturing cost can be suppressed.

  In addition to arranging the plurality of heat conduction vias 4b so as to be substantially equidistant from the light emitting diode 3, respectively, the heat conduction via 4b is further rotationally symmetric with the light emitting diode 3 as the rotation center. By arranging, it is possible to further suppress the occurrence of uneven heat transfer.

  Moreover, the material used for the multilayer wiring patterns 2a and 2b is not limited to the above-described material. For example, a multilayer including copper (thermal conductivity: about 400 W / mK) is relatively inexpensive and has a high thermal conductivity. Wiring can be formed.

<Second Embodiment>
A second embodiment of the present invention will be described with reference to the drawings.

  FIG. 4 is a plan view showing the arrangement of each via in the substrate 1 according to the present embodiment. In the present embodiment, in the light emitting device 100 of the first embodiment, the range in which the surface multilayer wiring pattern 2a is disposed is reduced and the heat conduction vias 4b are disposed in a concentrated manner. In addition, the same code | symbol is attached | subjected to the member similar to 1st Embodiment, and description is abbreviate | omitted.

  In FIG. 4, the surface multilayer wiring pattern 2a is divided into two regions insulated from each other, and the light emitting diode 3 is mounted so as to straddle the two regions of the surface multilayer wiring pattern 2a. The surface multilayer wiring pattern 2 a is disposed so as to extend in opposite directions with respect to the position where the light emitting diode 3 is disposed, and is rotationally symmetric about the light emitting diode 3. In two regions of the surface multilayer wiring pattern 2a, a heat conduction via 4b is arranged at the end opposite to the position where the light emitting diode 3 is mounted.

  Other configurations are the same as those of the first embodiment.

  Also in the present embodiment configured as described above, the same effects as those of the first embodiment can be obtained.

  Further, since heat energy is easily transferred to a material having lower thermal conductivity, more heat generated in the light emitting diode 3 is transferred to the surface multilayer wiring pattern 2b than the substrate 1. Accordingly, by efficiently arranging the surface multilayer wiring pattern 2b, other elements such as a temperature sensor can be mounted at a position where the surface multilayer wiring pattern 2a is not disposed.

<Third Embodiment>
A third embodiment of the present invention will be described with reference to the drawings.

  FIG. 5 is a plan view showing the arrangement of each via in the substrate 1 according to the present embodiment. In the present embodiment, in the light emitting device 100 of the first embodiment, the heat conduction via 4b is a line-shaped heat conduction via 4c. In addition, the same code | symbol is attached | subjected to the member similar to 1st Embodiment, and description is abbreviate | omitted.

  In FIG. 5, the surface multilayer wiring pattern 2a is divided into two regions insulated from each other, and the light emitting diode 3 is mounted so as to straddle the two regions of the surface multilayer wiring pattern 2a. The surface multilayer wiring pattern 2a is rotationally symmetric about the position where the light emitting diode 3 is disposed. Further, in the two regions of the surface multilayer wiring pattern 2a, the thermal conduction vias 4c are arranged so as to be rotationally symmetric about the position where the light emitting diode 3 is arranged.

  Other configurations are the same as those of the first embodiment.

  Also in the present embodiment configured as described above, the same effects as those of the first embodiment can be obtained.

  In the present embodiment, as a method of forming the heat conduction via 4c, for example, there is a cofire method. The cofire method is a method in which through holes are drilled in a ceramic precursor before sintering called a ceramic green sheet, and then the through holes are filled with metal powder (for example, tungsten) and fired.

<Fourth embodiment>
A fourth embodiment of the present invention will be described with reference to the drawings.

  FIG. 6 is a plan view showing the arrangement of each via in the substrate 1 according to the present embodiment. In the present embodiment, in the light emitting device 100 of the first embodiment, the total distance from the electrical conduction via 4a to each thermal conduction via 4b is the same in the two regions of the surface multilayer wiring pattern 2a. As shown, these thermal conduction vias 4b are arranged. In addition, the same code | symbol is attached | subjected to the member similar to 1st Embodiment, and description is abbreviate | omitted.

  In FIG. 6, the surface multilayer wiring pattern 2a is divided into two regions insulated from each other, and the light emitting diode 3 is mounted so as to straddle the two regions of the surface multilayer wiring pattern 2a. Further, in each of the two regions of the surface multilayer wiring pattern 2a, the heat conduction via 4b is arranged so that the sum of the distances from the electric conduction via 4a to each heat conduction via 4b is the same.

  Other configurations are the same as those of the first embodiment.

  Also in the present embodiment configured as described above, the same effects as those of the first embodiment can be obtained.

  Also, as shown in FIG. 6, when the light-emitting diodes 3 are arranged on one side of the substrate 1, the sum of the lengths of the electrical conduction vias 4a to the heat conduction vias 4b is made equal. As a result, the heat flow in the substrate 1 can be made uniform. Thereby, heat can be uniformly diffused on the back surface (back surface multilayer wiring pattern 2 b) of the substrate 1.

<Fifth and sixth embodiments>
The fifth and sixth embodiments of the present invention will be described with reference to the drawings.

  The fifth and sixth embodiments are implemented when the via 4c or 4d having a different configuration is applied to the electrical conduction via 4a and the thermal conduction via 4b in the first embodiment shown in FIG. It is a form.

  7 and 8 are enlarged cross-sectional views showing the vias in the substrate 1 according to the fifth and sixth embodiments of the present invention. 7 and 8, members that are the same as those shown in FIG. 1 are given the same reference numerals, and descriptions thereof are omitted.

  That is, the via 4c in the fifth embodiment of the present invention shown in FIG. 7 is formed by the following procedure. First, a mask corresponding to microblasting is formed on the substrate 1 made of ceramics, and a through hole constituting the via 4c is formed from one side of the substrate 1 by microblasting. After the formation of the through hole, a metal film is also formed in the through hole by forming the multilayer wiring patterns 2a and 2b with a metal film so as to include the through hole for the via 4c using a resist or the like, and the surface multilayer wiring pattern 2a And the back surface multilayer wiring pattern 2b are electrically and thermally connected. The via 4c is formed, for example, by forming titanium or chromium as a base film on the inner surface of the through hole, forming a nickel and gold film, and embedding the through hole by electrolytic copper plating. At this time, the plating is stopped in a state where the air layer 13 is formed, instead of filling the entire through hole for the via 4c by electrolytic copper plating. Other configurations are the same as those of the first embodiment.

  Similarly, the via 4d in the sixth embodiment of the present invention shown in FIG. 8 is formed by the following procedure. First, a mask corresponding to microblasting is formed on the substrate 1 formed of ceramics, and through holes constituting the vias 4d are formed from both sides of the substrate 1 by microblasting. After the through holes are formed, the multilayer wiring patterns 2a and 2b are formed of a metal film so as to include the through holes for the vias 4d using a resist or the like, whereby a metal film is also formed in the through holes, and the surface multilayer wiring pattern 2a And the back surface multilayer wiring pattern 2b are electrically and thermally connected. The via 4d is formed, for example, by forming titanium or chromium as a base film on the inner surface of the through hole, forming a nickel and gold film, and embedding the through hole by electrolytic copper plating. At this time, the plating is stopped in a state where the air layer 13 is formed, instead of filling the entire through hole for the via 4d by electrolytic copper plating. Other configurations are the same as those of the first embodiment.

  In the fifth and sixth embodiments configured as described above, the same effects as in the first embodiment can be obtained.

  Further, since the vias 4c and 4d are formed without embedding through holes for vias entirely by electrolytic copper plating, the step of performing electrolytic copper plating can be shortened, and the through holes are completely embedded by electrolytic copper plating. As a result, it is possible to shorten the step of smoothing the portion of the copper that protrudes from the surface and grows by grinding or polishing, so that productivity can be improved.

<Seventh embodiment>
A seventh embodiment of the present invention will be described with reference to the drawings.

  In this embodiment, a reflector 8, a resin lens 9, and a cooling fin 10 are provided in the first embodiment shown in FIGS.

  FIG. 9 is a cross-sectional view schematically showing the overall configuration of a light emitting device 200 according to the seventh embodiment of the present invention, and FIG. 10 is a schematic view showing how heat generated from the light emitting diode 3 is transferred. It is. 9 and 10, members that are the same as those shown in FIGS. 1 and 2 are given the same reference numerals, and descriptions thereof are omitted.

  9, the light emitting device 200 includes a substrate 1 formed of an insulating member, a surface multilayer wiring pattern 2a formed on the surface of the substrate 1 (upper surface in FIG. 9), and the back surface of the substrate 1 (FIG. 9). A plurality (for example, two) of the back surface multilayer wiring pattern 2b formed on the middle lower surface and the substrate 1 that are provided through the substrate 1 and electrically connect the front surface multilayer wiring pattern 2a and the back surface multilayer wiring pattern 2b. The electrical conduction via 4a (see FIG. 3 later), the light emitting diode 3 mounted on the surface of the substrate 1 so as to be electrically connected to the surface multilayer wiring pattern 2b, and the substrate 1 are provided. A plurality of (for example, six: see FIG. 3) thermal conduction vias 4b that thermally connect the front surface multilayer wiring pattern 2a and the back surface multilayer wiring pattern 2b, and the light 14 from the light emitting diode 3 (the following FIG. 10). Refre that reflects upward) A motor 8, and a resin lens 9 provided so as to cover the light-emitting diode 9, and a cooling fin 10 which is joined via a bonding layer 6 on the back surface of the substrate 1. The surface multilayer wiring pattern 2a has a plurality of (for example, two) regions insulated from each other, and the light emitting diode 3 is mounted so as to straddle these regions. The light emitting diode 3 mounted on the light emitting device 200 is electrically connected to a power source (not shown) via the front surface multilayer wiring pattern 2a, the electrical conduction via 4a, and the back surface multilayer wiring pattern 2b, and supplies power from the power source. Light is emitted.

  A reflective film (not shown) is provided on the surface of the reflector 8, and reflects light from the light emitting diode 3 forward (upper side in FIG. 9).

  The cooling fin 10 radiates heat transferred from the substrate 1 through the bonding layer 6 into the atmosphere. The cooling fin 10 is made of silicon nitride containing beryllium, for example. Silicon nitride is insulative and has a heat transfer coefficient of about 300 W / mK.

  The joining layer 6 is formed by, for example, gold-tin solder. Gold-tin solder has a melting point of about 280 ° C., and has higher heat resistance than a general heat conductive sheet (heat-resistant temperature is about 120 ° C.). When the cooling fin 10 is formed of an insulating material, the bonding layer 6 can be configured with a pattern similar to the back surface multilayer wiring pattern 2b formed on the back surface of the base 1 plate. Thereby, it is not necessary to join via an insulating sheet etc., and the fall of the heat transfer efficiency from the board | substrate 1 to the cooling fin 10 can be suppressed in the joining layer 6. FIG.

  Here, transmission of heat generated from the light emitting diode 3 in the light emitting device 200 will be described.

As shown in FIG. 10, a part of the heat generated in the light emitting diode 3 is transferred to the surface multilayer wiring pattern 2a of the substrate 1 as shown by an arrow 5c. The heat transferred to the surface multilayer wiring pattern 2a is transferred to the surface of the substrate 1 through the surface multilayer wiring pattern 2a as shown by the arrow 5d, and a part of the heat is transferred to the reflector 8 as shown by the arrow 5i. The light is emitted into the atmosphere of the light emitting device 200, a part is transmitted to the back surface multilayer wiring pattern 2b through the electrical conduction via 4a as shown by an arrow 5f, and a part is transmitted to the substrate 1 as shown by an arrow 5e. , A part is transmitted to the back surface multilayer wiring pattern 2b through the heat conduction via 4b as shown by the arrow 5g. Further, part of the heat conducted to the substrate 1 is transmitted to the back surface multilayer wiring pattern 2b as indicated by an arrow 5h. The heat transferred to the back surface multilayer wiring pattern 2b is further transferred to the cooling fin 10 through the bonding layer 6, and is released from the cooling fin 10 into the atmosphere. Operation in the present embodiment configured as described above Will be explained.

  In the light emitting device 200, when power is supplied from a power source (not shown) to the light emitting diode 3 through the back surface multilayer wiring pattern 2b, the electrical conduction via 4a, and the front surface multilayer wiring pattern 2a, the light emitting diode 3 emits light and generates heat. . The light generated by the light emitting diode 3 is emitted directly or reflected by the reflecting film of the reflector 8 and emitted to the front of the light emitting device 200 (upper side in FIG. 9). A part of the heat generated in the light emitting diode 3 is transmitted to the back surface multilayer wiring pattern 2b through the electrical conduction via 4a and released into the atmosphere of the light emitting device 200, and the other part is a surface multilayer wiring pattern. 2a and the heat conduction via 4b are transmitted to the back surface multilayer wiring pattern 2b, and are further transmitted to the cooling fin 10 through the bonding layer 6 to be emitted into the atmosphere of the light emitting device 200.

  Other configurations are the same as those of the first embodiment of the present embodiment.

  Here, as a result of performing a simulation on heat transfer in the light emitting device 200, the temperature difference between the temperature of the light emitting diode 3 and the lower surface of the cooling fin 10 is about 10 degrees. From this result, it can be confirmed that the efficiency of heat transfer from the light emitting diode 3 to the cooling fin 10 of the light emitting device 200 in the present embodiment is high and the cooling effect is high.

  In the present embodiment configured as described above, the same effect as in the first embodiment can be obtained.

  Further, since the cooling fin 10 having a large heat radiation area is joined to the back surface multilayer wiring pattern 2b to increase the heat radiation effect from the back surface of the light emitting device 200, the temperature rise in the light emitting device 200 can be further suppressed. Accordingly, it is possible to suppress a decrease in the light emission efficiency of the light emitting diode 3.

  In addition, although the case where the silicon nitride was used as an example of the material of the cooling fin 10 was demonstrated, it is not restricted to this, For example, you may form the cooling fin 10 using a silicon carbide. In this case, since the linear expansion coefficients of the substrate 1 and the cooling fin 10 formed of ceramics can be made equal, even when the temperature around the bonding layer 6 for bonding them changes, it takes between them. The force is suppressed, and deformation of the light emitting device 200 and peeling of the substrate 1 and the cooling fin 10 can be suppressed.

  Further, although gold-tin solder is used as the bonding layer 6 for bonding the substrate 1 and the cooling fin 10, the present invention is not limited to this. For example, the surface is activated with plasma or ion beam in a vacuum, and then bonded at a low temperature. Both may be bonded using surface active bonding.

  Furthermore, an air flow may be intentionally created around the cooling fin 10 or the cooling fin 10 may be water-cooled, thereby further improving the cooling effect.

  Further, when the insulation between the substrate 1 and the cooling fin 10 is ensured by an appropriate method, a cooling fin made of metal may be used. Even in this case, the performance of heat transfer from the light emitting diode 3 to the back surface multilayer wiring pattern 2b is ensured, so that the cooling effect of the light emitting device 200 can be obtained.

<Eighth Embodiment>
An eighth embodiment of the present invention will be described with reference to FIGS. In this embodiment, the cooling fin 50 shown in FIGS. 11 and 12 is used in place of the cooling fin 10 of the light emitting device 200 in the seventh embodiment shown in FIGS. 9 and 10. It is a form.

  FIG. 11 is a view of the cooling fin 50 according to the present embodiment as seen from the back side, and FIG. 12 is a longitudinal sectional view showing a part of the cross section of the cooling fin 50 in an enlarged manner. Hereinafter, in FIG. 11, the front side is the back side of the cooling fin 50 and the back side is the front side. In FIG. 12, the upper side is the back side of the cooling fin 50 and the lower side is the front side.

  In FIG. 11, the cooling fin 50 is formed by providing grooves 50b in a lattice pattern in the thickness direction on the back side surface, and the front side surface is bonded to the substrate 1 with the bonding layer 6 (see FIGS. 9 and 10 described above). (See Fig.). In addition, in FIG. 12, the end 50a on the back side of the groove 50b of the cooling fin 50 is configured to have a plurality of surfaces.

  Moreover, the cooling fin 50 is formed with the insulating member, for example, is formed with the silicon carbide containing beryllium. The thickness of the cooling fin 50 is, for example, about 2 mm. However, when the thickness is increased, the cooling fin 50 has an insulating property to a conductive property. Accordingly, the groove 50b is formed in a silicon carbide (containing beryllium) having a thickness exhibiting insulating properties by a dicing machine or the like.

  Further, in order to improve the cooling efficiency in the cooling fin 50, the effect is enhanced by increasing the surface area. However, if the surface area is increased, the interval between the grooves 50b in the cooling fin 50 is narrowed and damaged. It becomes easy. In view of this, the end of the groove 50b is shaped so that stress is not easily concentrated, thereby preventing the cooling fin 50 from being damaged. The shape of the end portion 50a can be achieved by setting the tip shape of the dicing blade to a desired shape.

  Other configurations are the same as those of the seventh embodiment.

  Also in the present embodiment configured as described above, the same effects as those of the first and seventh embodiments can be obtained.

<Ninth embodiment>
A ninth embodiment of the present invention will be described with reference to the drawings.

  In the present embodiment, a plurality of (for example, two layers) cooling fins 10 of the light emitting device 200 in the seventh embodiment shown in FIGS. 9 and 10 are stacked in the thickness direction. FIG. 13 is a cross-sectional view showing a configuration of cooling fin 10 according to the present embodiment. In the figure, members equivalent to those shown in FIG. 9 and FIG. In FIG. 13, the upper side is the front side of the cooling fin 10 and the lower side is the back side.

  As shown in FIG. 13, in the present embodiment, a plurality of (for example, two) cooling fins 10 are used, and the bonding layer 6 is attached to the back side of one cooling fin 10 and the surface of the other cooling fin 10. Are joined through. Other configurations are the same as those of the seventh embodiment.

  Also in the present embodiment configured as described above, the same effects as those of the first and seventh embodiments can be obtained.

  In addition, if the cooling fin 10 joined to the board | substrate 1 through the joining layer 6 is formed using silicon carbide, you may use the material of the other cooling fin 10 for other materials.

<Tenth and eleventh embodiments>
Tenth and eleventh embodiments of the present invention will be described with reference to the drawings.

  In the light emitting device 200 according to the seventh embodiment shown in FIGS. 9 and 10, one light emitting diode 3 is mounted. In the present embodiment, a plurality of (for example, two) light emitting diodes are provided in the light emitting device 300. 3 is installed. FIG. 14 is a cross-sectional view showing a configuration of a light-emitting device 300 according to the tenth embodiment, and FIG. 15 is a cross-sectional view showing a configuration of a light-emitting device 400 according to the eleventh embodiment. In the figure, members equivalent to those shown in FIGS. 9 and 10 are denoted by the same reference numerals, and description thereof is omitted.

  A light-emitting device 300 according to the tenth embodiment shown in FIG. 14 includes a substrate 1 formed of an insulating member and a surface multilayer wiring pattern 2a formed on the surface of the substrate 1 (the upper surface in FIG. 14). And the back surface multilayer wiring pattern 2b formed on the back surface of the substrate 1 (the lower surface in FIG. 14) and the substrate 1 so as to electrically connect the front surface multilayer wiring pattern 2a and the back surface multilayer wiring pattern 2b. A plurality (for example, four) of electrically conductive vias 4a connected to the substrate, and a plurality (for example, two) of light emitting diodes 3 mounted on the surface of the substrate 1 so as to be electrically connected to the surface multilayer wiring pattern 2b; A plurality of (for example, six) thermal conduction vias 4b provided through the substrate 1 and thermally connecting the front surface multilayer wiring pattern 2a and the back surface multilayer wiring pattern 2b, and a bonding layer 6 on the back surface of the substrate 1. The cooling film joined through And a 10. The front surface multilayer wiring pattern 2a and the back surface multilayer wiring pattern 2b are provided separately corresponding to each of the plurality of light emitting diodes 3, and the multilayer wiring patterns 2a, 2b corresponding to the respective light emitting diodes 3 are insulated from each other. It has the area of. Each light emitting diode 3 is mounted so as to straddle these regions. The light emitting diodes 3 mounted on the light emitting device 200 are electrically connected to a power source (not shown) via the corresponding front surface multilayer wiring pattern 2a, electrical conduction via 4a, and back surface multilayer wiring pattern 2b. Light is emitted when power is supplied. Other configurations are the same as those of the seventh embodiment of the present invention.

  Similarly, the light-emitting device 400 according to the eleventh embodiment shown in FIG. 15 includes a substrate 1 formed of an insulating member and a surface multilayer formed on the surface of the substrate 1 (the upper surface in FIG. 15). A wiring pattern 2a, a back surface multilayer wiring pattern 2b formed on the back surface of the substrate 1 (the lower surface in FIG. 15), a front surface multilayer wiring pattern 2a and a back surface multilayer wiring pattern 2b provided through the substrate 1; A plurality of (for example, four) electrical conduction vias 4a that electrically connect the plurality of (for example, two) light emitting devices mounted on the surface of the substrate 1 so as to be electrically connected to the surface multilayer wiring pattern 2b. A plurality of (for example, six) thermal conduction vias 4b provided through the diode 3 and penetrating the substrate 1 and thermally connecting the front surface multilayer wiring pattern 2a and the back surface multilayer wiring pattern 2b; Bonded via the bonding layer 6 And retirement fins 10, and a wire 12 connected to the back multilayer wiring pattern 2b. The front surface multilayer wiring pattern 2a and the back surface multilayer wiring pattern 2b are provided separately corresponding to each of the plurality of light emitting diodes 3, and the multilayer wiring patterns 2a, 2b corresponding to the respective light emitting diodes 3 are insulated from each other. It has the area of. Each light emitting diode 3 is mounted so as to straddle these regions, and is arranged electrically in series, for example. The light emitting diode 3 mounted on the light emitting device 400 is electrically connected to a power source (not shown) via the front surface multilayer wiring pattern 2a, the electrical conduction via 4a, and the back surface multilayer wiring pattern 2b, and supplies power from the power source. Light is emitted. Other configurations are the same as those of the seventh embodiment of the present invention.

  Also in the tenth and eleventh embodiments configured as described above, the same effects as those in the first and seventh embodiments can be obtained.

<Other embodiments>
Although several embodiments of the present invention have been described above, these embodiments can be variously modified and combined within the spirit of the present invention. For example, in the first to fourth embodiments, the arrangement of the vias 4a and 4b shown in FIGS. 3 to 5 is applied. Similarly, in the fifth to eleventh embodiments, FIGS. The arrangement of the vias 4a and 4b shown in FIG. In the fifth and sixth embodiments, the vias 4c and 4d shown in FIGS. 7 and 8 are applied. However, the same can be applied to other embodiments.

DESCRIPTION OF SYMBOLS 1 Insulation board | substrate 2a, 2b Multilayer wiring pattern 3 Light emitting diode 4a Embedded via 4b, 4c Conductive conduction via 6 Junction layer 8 LED reflector 9 Resin lens 10, 50 Cooling fin 11 Circumference 50b Groove structure 12 Wiring 13 Space 14 Light 100, 200, 300, 400 Light-emitting device

Claims (9)

A substrate formed of ceramics;
A light emitting diode mounted on the surface of the substrate;
Surface metal wiring formed on the surface of the substrate and electrically connected to the light emitting diode;
Backside metal wiring formed on the backside of the substrate;
A plurality of vias for electrical conduction formed through the substrate and electrically connecting the front surface metal wiring and the back surface metal wiring;
A light emitting device comprising one or more heat conduction vias formed through the substrate and thermally connecting the front surface metal wiring and the back surface metal wiring. The light-emitting device according to claim 1.
The light-emitting device, wherein the plurality of heat conduction vias are arranged point-symmetrically with respect to the light-emitting diode. The light-emitting device according to claim 1.
The light emitting diode is mounted across a region of the surface metal wiring that is insulated from each other, and the heat conduction via is a total distance from the light emitting diode to each heat conduction via in each region of the surface metal wiring. A light-emitting device that is arranged to be the same. The light-emitting device according to claim 1.
A light emitting device comprising a heat dissipating fin thermally bonded to the back surface metal wiring on the back surface of the substrate. In the light emitting device according to claim,
The heat-radiating fin is formed of silicon carbide. The light-emitting device according to claim 1.
2. The light emitting device according to claim 1, wherein the ceramic on which the substrate is formed is any one of alumina, silicon carbide, and aluminum nitride. The light-emitting device according to claim 1.
The light emitting device, wherein the via is formed by using an electrolytic copper plating method. The light-emitting device according to claim 1.
The light emitting device, wherein the substrate, the front surface metal wiring, the back surface metal wiring, the electrical conduction via, and the thermal conduction via are formed of an inorganic material. A substrate formed of ceramics for mounting a light emitting diode;
Surface metal wiring formed on the surface of the substrate and electrically connected to the light emitting diode;
Backside metal wiring formed on the backside of the substrate;
A plurality of vias for electrical conduction formed through the substrate and electrically connecting the front surface metal wiring and the back surface metal wiring;
A substrate for a light-emitting device, comprising a plurality of thermal conduction vias formed through the substrate and thermally connecting the front surface metal wiring and the back surface metal wiring.

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