JP6567305B2 - LED light source - Google Patents

Description

  The present invention relates to an LED light source, and more particularly to an LED light source formed by mounting an LED element of a light emitting source on a substrate.

  Conventionally, this type of “LED light source” is disclosed in Patent Document 1 under the name of “light emitting device”.

  The disclosed light emitting device has a configuration in which an LED chip is bonded to a laminated alumina substrate having a two-layer structure.

  Specifically, as shown in FIG. 10, the first layer alumina sheet 80 and the second layer alumina sheet 81 are bonded together to form a laminated alumina substrate 82 having a two-layer structure. Each of the pair of electrode pads 83 made of a metal film formed on the upper surface and the pair of back surface extraction electrodes 84 made of a metal film formed on the back surface of the first layer alumina sheet 80 has Ag (silver) embedded therein. The plurality of through holes 85 are electrically connected.

  In the LED chip 86, a p-electrode 88 and an n-electrode 89 are formed on the LED light emitting layer 87, and a part of each of the electrodes 88 and 89 is exposed from an insulating protective film (not shown), and is exposed from the insulating protective film. Each of the p electrode 88 and the n electrode 89 is mechanically and electrically bonded to each of the pair of electrode pads 83 of the laminated alumina substrate 82 via the Au bump 90 and the silver paste 91. The LED chip 86 is further fixed on the laminated alumina substrate 82 by an underfill resin 92 filled between the LED chip 86 and the laminated alumina substrate 82.

  As a result, the LED chip 86 is mounted on the laminated alumina substrate 82 having the same size as the LED chip 86 and the light emitting device 100 can be reduced in size, and the p-electrode 88 and the n-electrode 89 of the LED chip 86 can be reduced. A plurality of through-holes in which a pair of electrode pads 83 formed on the upper surface of the second-layer alumina sheet 81, mechanically and electrically bonded via the Au bump 90 and the silver paste 91, are embedded with silver. The light emitting device 100 can be thinned by being electrically connected to the pair of back surface extraction electrodes 84 formed on the back surface of the first layer alumina sheet 80 via 85.

  The light emitted from the LED light emitting layer 87 passes through the sapphire substrate 93 having translucency, which is located on the opposite side of the LED light emitting layer 87 from the side where the p electrode 88 and the n electrode 89 are located. Is emitted. Therefore, the luminance of the light emitting device 100 can be increased.

  Further, the laminated alumina substrate 82 includes a pair of electrode pads 83 formed on the upper surface of the second layer alumina sheet 81 and a pair of back surface extraction electrodes 84 formed on the back surface of the first layer alumina sheet 80. It is said that it has good thermal conductivity and good heat resistance because it is connected through a plurality of through holes 85 embedded with silver.

JP2012-165016A

  By the way, the light emitting device 100 configured as described above has a configuration in which the laminated alumina substrate 82 is mounted with the LED chip 86 in which the p electrode 88 and the n electrode 89 are formed only on one surface side. In addition, the LED chip in which the n electrodes are formed on both sides facing each other cannot be mounted.

  In recent years, in addition to ceramic, the base material of the substrate is often used LTCC (low temperature co-fired ceramic) in order to reduce the cost. Moreover, in order to improve light extraction, there is a demand to place two high-power (high heat generation) LED elements as close as possible. Although it is sufficient that the two LED elements are sufficiently separated as shown in FIG. 10, heat dissipation can be ensured by increasing the size of the through hole. However, when the through-hole is large and two elements are arranged close to each other, the multilayer substrate has two through holes filled with silver having a relatively high thermal expansion coefficient during firing of the multilayer substrate by LTCC at around 1000 ° C. There is a problem that stress is concentrated due to the difference in thermal expansion in the hole and a portion located between the holes, causing a substrate crack. The LED chip 86 generates heat when the LED chip 86 emits light. The p electrode 88 and the n electrode 89 of the LED chip 86, the pair of electrode pads 83 of the laminated alumina substrate 82, a plurality of through holes 85 embedded with silver, The pair of back surface extraction electrodes 84 are sequentially conducted to escape to the outside. In that case, since there is a portion with a small cross-sectional area such as the Au bump 90 and the through hole 85 in the heat transfer path, the thermal resistance increases, the heat dissipation efficiency is lowered, and the temperature rise due to the self-heating of the LED chip 86 is sufficient. It is difficult to suppress.

  Therefore, the present invention was devised in view of the above problems, and the object of the present invention is to propose a laminated structure that prevents cracking during substrate firing, and to ensure high reliability by ensuring good heat dissipation efficiency. Therefore, it is possible to reduce the size of the light emitting device.

In order to solve the above-mentioned problem, the invention described in claim 1 of the present invention includes a laminated substrate formed by bonding two LTCC substrates of a first substrate and a second substrate, and an element electrode on a surface facing each other. The first substrate has a pair of die bonding pads on which each of the two LED elements is placed, and a window hole penetrating in the thickness direction connected to each die bonding pad. A pair of first metal structures that are filled with metal, and the second substrate is filled with metal in a pair of heat-dissipating electrodes and a window hole that passes through each of the heat-dissipating electrodes and penetrates in the thickness direction. Each of the pair of die bonding pads and each of the pair of heat radiation electrodes are each of the pair of first metal structures and the pair of second metal structures. Connected via each of the metal structures The first metal structure and the second metal structure connected to each other have a cross-sectional area of the second metal structure larger than a cross-sectional area of the first metal structure, and the pair of first metal structures. than the spacing between the metal structure rather is wide toward the spacing between the second metal structure of the pair, each of the intervals, a pair of respective located at a respective spacing of the metal structure, the pair When the length in the arrangement direction of the metal structure is the same, it is 85% or more of the length, and when the length is different, it is 85% or more of the longer length .

The invention described in claim 2 of the present invention is that in claim 1, the metal filling the window hole of the first substrate and the metal filling the window hole of the second substrate are both silver and silver. It is characterized by being the main metal .

  According to the LED light source of the present invention, the pair of die bonding pads and the pair of heat radiation electrodes provided on the mutually opposing surfaces of the laminated substrate of the two LTCC substrates of the first substrate and the second substrate are provided on the first substrate. And a pair of first metal structures and second metal structures provided on each of the second substrates. In this case, each cross-sectional area of the second metal structure is set larger than each cross-sectional area of the first metal structure, and an interval between the second metal structures is set larger than an interval between the first metal structures. Largely set.

  As a result, the heat generated from the LED element is efficiently radiated, so that the influence of the heat of the LED element on the high-density mounting of the LED element is suppressed, and the LED light source is small while ensuring high reliability. Can be realized.

It is a top view of the LED light source which concerns on embodiment. Similarly, it is a bottom view according to the embodiment. It is an AA cross-sectional arrow view of FIG. It is a cross-sectional schematic diagram explaining the electrical connection of the LED light source which concerns on embodiment. It is explanatory drawing of the state which mounted the LED light source on the board | substrate. It is the top view which removed the LED element and the die pad from the LED light source. It is an AA cross-sectional arrow view of FIG. It is a partial block diagram of the conventional LED light source. It is explanatory drawing of the example of application of a LED light source. It is explanatory drawing of a prior art example.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. 1 to 9 (the same reference numerals are given to the same portions). The embodiments described below are preferable specific examples of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention particularly limits the present invention in the following description. Unless stated to the effect, the present invention is not limited to these embodiments.

  1 is a plan view of an LED light source according to an embodiment of the present invention, FIG. 2 is a bottom view, FIG. 3 is a cross-sectional view taken along line AA in FIG. 1, and FIG. is there.

  The LED light source 1 of the embodiment forms a laminated substrate 30 by bonding two substrates (first substrate 10 and second substrate 20) each made of LTCC, and two LED elements (on the laminated substrate 30). LED chips) 2 and 3 are mounted side by side. In the LED light source 1 according to the embodiment, two substrates (first substrate 10 and second substrate 20) each made of LTCC are bonded together, and then the multilayer substrate 30 is formed by baking at around 1000 ° C. It has a configuration in which two LED elements (LED chips) 2 and 3 are mounted side by side.

  Although the two LED elements 2 and 3 are not shown, a pair of element electrodes (an anode electrode and a cathode electrode) are formed on both surfaces facing each other.

  The multilayer substrate 30 having a two-layer structure has a window hole in which each of the first substrate 10 and the second substrate 20 constituting the multilayer substrate 30 penetrates in a thickness direction at a predetermined position in a predetermined shape dimension. Metal structures (first metal structure 12 and second metal structure 22) are formed in the window holes. As a metal structure, it is comprised from the metal which has silver and silver as a main component. Specifically, platinum, rhodium, palladium, and ruthenium may be included in addition to silver as long as sintering is not inhibited. In addition, the substrate (first substrate) 10 on the side where the LED elements 2 and 3 are mounted, the surface (front surface) on which the LED elements 2 and 3 are mounted, and the second substrate 20 bonded to the first substrate 10. Conductive patterns are formed on both sides.

  The first substrate 10 constituting the laminated substrate 30 has a die bonding pad (hereinafter abbreviated as “die pad”) formed of a conductor pattern on which two LED elements 2 and 3 are mounted (die bonding). 11a and 11b are provided, and a bonding wire pad (hereinafter referred to as “wire pad”) to which the other end of the bonding wire is bonded to one of the element electrodes (upper electrodes) of one of the two LED elements 2 and 3 is bonded. 11c and 11d).

  In this case, the die pads 11a and 11b and the wire pads 11c and 11d are provided so as to be separated and independent from each other.

  Then, the LED elements 2 and 3 are bonded to the die pads 11a and 11b via conductive bonding members (not shown) such as silver paste, and the element electrodes (lower electrodes) of the LED elements 2 and 3 and the die pads 11a and 11b. And electrical continuity. On the other hand, the element electrodes (upper electrodes) of the LED elements 2 and 3 are connected to the wire pads 11c and 11d via the bonding wires 4a and 4b, and the upper electrodes of the LED elements 2 and 3 and the wire pads 11c and 11d are connected. Electrical continuity is achieved.

  On the other hand, the second substrate 20 constituting the multilayer substrate 30 is provided with a pair of heat radiation electrodes 23a and 23b made of a conductor pattern on the surface (back surface) opposite to the bonding surface to the first substrate 10, and externally. A pair of power receiving electrodes 23c and 23d for receiving power from the power source are provided.

  In this case, the heat radiation electrodes 23a and 23b and the power reception electrodes 23c and 23d are provided in a state of being separated and independent from each other.

  Below the two die pads 11a and 11b, there are provided first metal structures 12a and 12b electrically connected to the die pads 11a and 11b, respectively, and above the pair of heat radiation electrodes 23a and 23b. Are provided with second metal structures 22a and 22b electrically connected to the heat radiation electrodes 23a and 23b, respectively, and the first metal structure 12a, the second metal structure 22a, and the first metal structure. 12b and the second metal structure 22b are electrically connected.

  Further, as shown in the schematic cross-sectional view of FIG. 4, below the two wire pads 11c and 11d, there are provided first metal structures 12c and 12d electrically connected to the wire pads 11c and 11d, respectively. The second metal structures 22c and 22d electrically connected to the power receiving electrodes 23c and 23d are provided above the pair of power receiving electrodes 23c and 23d, respectively. The structure 12c and the second metal structure 22c are electrically connected.

  On the bonding surface (inner surface) of the second substrate 20 with respect to the first substrate 10, wiring pads 21ad and 21bd made of a conductor pattern are provided.

  The wiring pad 21ad is electrically connected to the first metal structures 12a and 12d of the first substrate 10 at the same time as being connected to the second metal structure 22a of the second substrate 20, and the wiring pad 21bd is electrically connected to the second substrate 20. The second metal structures 22b and 22d are electrically connected to the first metal structure 12b of the first substrate 10 at the same time.

  Next, the electrical circuit configuration of the LED light source 1 will be described with reference to FIG. The power receiving electrode 23c is connected to the upper electrode of the LED element 2 through the second metal structure 22c, the first metal structure 12c, the wire pad 11c, and the bonding wire 4a, and the lower electrode of the LED element 2 is connected to the die pad 11a, The first metal structure 12a, the wiring pad 21ab, the first metal structure 12d, the wire pad 11d, and the bonding wire 4b are connected to the upper electrode of the LED element 3. Further, the lower electrode of the LED element 3 is connected to the power receiving electrode 23d through the die pad 11b, the first metal structure 12b, the wiring pad 21bd, and the second metal structure 22d.

  Therefore, when the upper electrode of each of the LED elements 2 and 3 is an anode electrode and the lower electrode is a cathode electrode, a (+) side voltage is applied to the power receiving electrode 23c and a (−) side voltage is applied to the power receiving electrode 23d. By doing so, the two LED elements 2 and 3 are simultaneously lit (emitted).

  Further, by applying a (+) side voltage to the power receiving electrode 23c and applying a (−) side voltage to the heat radiating electrode 23a, the LED element 2 is turned on, and a (+) side voltage is applied to the heat radiating electrode 23a. Then, the LED 3 is turned on by applying a (−) side voltage to the power receiving electrode 23d. Thereby, lighting control of each of the two LED elements 2 and 3 can be performed individually.

  By the way, the LED elements 2 and 3 generate heat at the time of lighting (light emission), and due to a temperature rise due to self-heating, the light emission efficiency of the LED elements 2 and 3 and the element life are reduced. Therefore, when the LED light source 1 is mounted on the LED light source mounting substrate 40, as shown in FIG. 5 (an explanatory diagram of the state where the LED light source is mounted on the substrate), the heat radiation electrode 23a of the LED light source 1 is mounted on the LED light source mounting substrate 40. , 23b are provided for heat radiation electrode bonding pads 41a and 41b. Although not shown in the figure, the LED light source mounting substrate 40 is also provided with a power receiving electrode bonding pad for bonding the power receiving electrodes 23c and 23d of the LED light source 1.

  Then, heat generated by one of the two LED elements 2 and 3 is conducted to the heat dissipation electrode 23a via the die pad 11a, the first metal structure 12a, and the second metal structure 22a, and the heat dissipation electrode. Conductive to the heat radiation electrode bonding pad 41a of the LED light source mounting substrate 40 to which the light source 23a is bonded is diffused out of the LED light source 1 through the heat radiation electrode bonding pad 41a.

  Similarly, heat generated by the other LED element 3 of the two LED elements 2 and 3 is conducted to the heat dissipation electrode 23b via the die pad 11b, the first metal structure 12b, and the second metal structure 22b, and is used for heat dissipation. The light is transmitted to the heat radiation electrode bonding pad 41b of the LED light source mounting substrate 40 to which the electrode 23b is bonded, and is diffused out of the LED light source 1 through the heat radiation electrode bonding pad 41b.

  As a result, the heat generated by each of the LED elements 2 and 3 is efficiently radiated and the temperature increase due to the self-heating of the LED elements 2 and 3 itself is suppressed, and the light emission efficiency of the LED elements 2 and 3 due to the temperature increase is reduced. The decrease in the amount of emitted light can be suppressed, and the shortening of the light emission life due to the deterioration of the LED elements 2 and 3 due to the temperature rise of the LED elements 2 and 3 can be suppressed. A sufficient amount of irradiation light can be secured.

  In the LED light source 1 of the present invention, in order to improve the cracking failure when firing the multilayer substrate and to increase the heat dissipation efficiency and the reliability of the multilayer substrate 30 against the heat generated by the LED elements 2 and 3, First metal structures 12a and 12b, and first metal structures 12a, which are located below the die pads 11a and 11b on which the LED elements 2 and 3 are mounted and are electrically connected to the die pads 11a and 11b, respectively. Of the four metal structures 12a, 12b, 22a, and 22b of the second metal structures 22a and 22b that are located below the electric lines 12b and electrically connected to the first metal structures 12a and 12b, respectively. The relationship was specially defined.

  Specifically, as shown in FIG. 6 (a plan view in which the LED element and the die pad are removed from the LED light source), the cross section S2a of the second metal structure 22a is positioned above the second metal structure 22a. Similarly, the sectional area S2b of the second metal structure 22b is set larger than the sectional area S1b of the first metal structure 12b located above the second metal structure 22b. Set larger.

  Thereby, the cross-sectional area of a conduction path becomes large as it leaves | separates from each of the LED elements 2 and 3, and the thermal radiation effect can be heightened by diffusion of heat (refer FIG. 5).

  Moreover, as shown in FIG. 7 (AA cross-sectional arrow view of FIG. 1), in the juxtaposed direction of the LED elements 2 and 3, the length of the adjacent first metal structure 12a is a, the first metal structure The length of the body 12b is b, the distance between the first metal structure 12a and the first metal structure 12b is c, the length of the adjacent second metal structure 22a is d, and the second metal structure When the length of the body 22b is e and the distance between the second metal structure 22a and the second metal structure 22b is f, the relationship f> c, that is, the first metal structure 12a and the first metal structure The distance c between the second metal structure 22a and the second metal structure 22b is set to be narrower than the distance c between the second metal structure 22a and the second metal structure 22b. Further, the lengths d and e of the second metal structures 22a and 22b are set longer than the lengths a and b of the first metal structures 12a and 12b, respectively.

  At the same time, the relationship between the length a of the first metal structure 12a, the length b of the first metal structure 12b, and the distance c is set such that when a = b, c ≧ a × 0.85 = b × 0. If a and b are different and either one (for example, a) is long (when a> b), c ≧ a × 0.85 is set. That is, when the lengths of the first metal structures 12a and 12b on the left and right sides with the interval c are different, the interval c is 85% or more of the length of the longer first metal structure. Set to.

  Similarly, the relationship between the length d of the second metal structure 22a, the length e of the second metal structure 22b, and the distance f is f = d × 0.85 = e × 0. When d and e are different and either one (for example, d) is long (d> e), f ≧ d × 0.85 is set. That is, when the lengths of the left and right second metal structures 22a and 22b across the gap f are different, the gap f is 85% or more of the length of the longer second metal structure. Set to.

  Accordingly, the size of the region of the interval c is set to a size corresponding to the heat capacity conducted from the first metal structures 12a and 12b sandwiching the interval c, and similarly, the size of the region of the interval f is set to the interval f. The size corresponds to the heat capacity conducted from the sandwiched second metal structures 22a and 22b. As a result, the heat density of the heat generated in the LED elements 2 and 3 and gathered in the region A surrounded by the four metal structures 12a, 12b, 22a and 22b of the multilayer substrate 30 is reduced. Therefore, it is possible to prevent cracking and breakage occurring in the region A. In particular, by setting the interval c to 85% or more of the first metal structures 12a and 12b, the stress applied to the LTCC located in the region of the interval c from the first metal structures 12a and 12b on both sides during firing is relieved, Substrate cracking can be prevented.

  Inventors evaluated the crack of the board | substrate after baking by changing the distance of the space | interval c between the 1st metal structure 12a and the 1st metal structure 12b. There are three types of evaluation samples. In each sample, the length a of the first metal structure 12a and the length b of the first metal structure 12b are both 0.7 mm, and the length d of the second metal structure 22a. And the length e of the second metal structure 22b is 0.93 mm, the size of the LED element is 1 mm □, the length a of the first metal structure 12a, the first metal structure 12a, The relationship (c / a) with the distance c from the first metal structure 12b was set to (c / a) = 1, 0.85, and 0.7, respectively.

  As a result, the sample with (c / a) = 0.7 is cracked on the substrate (evaluation result: x), and the sample with (c / a) = 0.85 is hardly cracked on the substrate (evaluation) Results: Δ), yield improved. Furthermore, the sample of (c / a) = 1 did not crack at all on the substrate (evaluation result: ◯). From the above, it is possible to substantially prevent substrate cracking during firing by setting (c / a) ≧ 0.85, and more preferably to prevent cracking completely by setting (c / a) ≧ 1. I knew it was possible.

  From the evaluation results, the distance f between the second metal structure 22a and the second metal structure 22b is also 85% of the length d of the second metal structure 22a and the length e of the second metal structure 22b. Needless to say, the substrate can be prevented from cracking as described above. That is, in the case of a two-layer laminated structure, if c and f are set to 85% or more of the length of the metal structure located on both sides, substrate cracking during firing can be prevented.

  That is, for example, a conventional configuration in which the interval c and the interval f are the same regardless of the size of the four metal structures 12a, 12b, 22a, and 22b (see FIG. 8 (partial configuration diagram of a conventional LED light source)). The problem of cracks and breakage occurring in the region A due to the thermal stress due to the heat generated by the LED elements 2 and 3 can be solved.

  By the way, in the above-described embodiment, the outer end face of the LED element is arranged near the outer end face of the first metal structure, or the length of the first metal structure is set to about 70% of the length of the LED element. However, the size of the metal structure should be adjusted to be as large as possible, and further, the position should be adjusted so that the metal structure is at the center of the LED element as much as possible. That is, it is necessary to maintain the close arrangement of the two LED elements and the arrangement of the intervals c and f, but the size and position of the first metal structure are the specifications of the size of the LED element, the output, the thermal resistance of the through hole, etc. Therefore, the positional relationship of the embodiment is merely an example.

  Further, the contact between the LED elements is not possible because it causes a leak failure, but the two LED elements of the embodiment are arranged close to each other, and the narrower the better as they do not contact. However, since it is determined depending on the size and tolerance of the LED elements or the positional accuracy of the mounting apparatus, it goes without saying that the inter-element distance of the embodiment is merely an example.

  In practical use, for example, the LED light source 1 described above has an annular side wall 42 at the periphery on the mounting surface of the LED elements 2 and 3 of the multilayer substrate 30 as shown in FIG. 9 (an explanatory diagram of an application example of the LED light source). The LED element 2, 3 and the bonding wires 4 a, 4 b may be resin-sealed by providing a sealing resin 43 made of a translucent resin in the side wall 42.

  Thereby, the LED elements 2 and 3 are protected from the external environment such as moisture, dust and gas, and the bonding wires 4a and 4b are protected from mechanical stresses such as vibration and impact. In addition, the sealing resin 43 forms an interface with the light emitting surfaces of the LED elements 2 and 3, and the emitted light of the LED elements 2 and 3 enters the sealing resin 43 from the light emitting surfaces of the LED elements 2 and 3. It also has a function of emitting light efficiently.

  Further, by using a transparent resin in which a phosphor is dispersed in the sealing resin 43, light having a hue different from the emission color of the LED elements 2 and 3 can be obtained.

  As described above, in the LED light source of the present invention, two LED elements having element electrodes on both sides facing each other are mounted on a laminated substrate formed by laminating two LTCC substrates, and the LED elements are mounted. The first metal structure formed on the first substrate and the second metal structure formed on the second substrate by connecting the heat dissipation electrode for radiating heat to the outside to the die pad and the second metal structure formed on the second substrate. A heat transfer path was formed by the structure and the second metal structure.

  And the cross-sectional area of the 2nd metal structure connected to the electrode for thermal radiation was set larger than the cross-sectional area of the 1st metal structure connected to a die pad. As a result, the cross-sectional area of the conduction path increases as the distance from the LED element increases, and the temperature increase due to the self-heating of the LED element itself is suppressed by the good heat dissipation effect due to the diffusion of heat, and the luminous efficiency of the LED element due to the temperature increase is reduced. The reduction of the amount of emitted light due to the reduction can be suppressed, and similarly the shortening of the light emitting life due to the deterioration of the LED element due to the temperature rise of the LED element can be suppressed, and as a result, high reliability and an appropriate amount of irradiation light can be achieved. Can be secured.

  Also, two second metal structures connected to each of the two first metal structures rather than the distance between the two first metal structures connected to each of the two die pads on which the two LED elements are mounted. The interval between the bodies was set wide, and each interval was set to be 85% or more of the length of the longer metal structure among the metal structures located on both sides of the interval. .

  As a result, the size of each interval region is set to a size corresponding to the heat capacity conducted from the metal structure sandwiching the interval. As a result, thermal stress applied to the LTCC located in the region of the distance c from the first metal structures 12a and 12b on both sides during substrate firing is relieved, and cracks generated in the portion of the LTCC region located in the region of the distance c and Breakage can be prevented.

  From the above, since the heat dissipation efficiency is good even for high-density mounting of LED elements, the influence of heat due to heat generation of the LED elements is suppressed, and the LED light source can be miniaturized while ensuring high reliability. .

DESCRIPTION OF SYMBOLS 1 ... LED light source 2 ... LED element
DESCRIPTION OF SYMBOLS 3 ... LED element 4 ... Bonding wire 4a ... Bonding wire 4b ... Bonding wire 10 ... 1st board | substrate 11 ... Electrode pad 11a, 11b ... Die pad 11c, 11d ... Wire pad 12 ... 1st metal structure 12a, 12b, 12c, 12d ... 1st metal structure 20 ... 2nd board | substrate 21 ... Wiring pad 21ad ... Wiring pad 21bd ... Wiring pad 22 ... 2nd metal structure 22a, 22b, 22c, 22d ... 2nd metal structure 23 ... Electrode 23a, 23b ... Radiation electrode 23c, 23d ... Receiving electrode 30 ... Laminated substrate 40 ... LED light source mounting substrate 41 ... Radiation electrode joint pad 41a ... Radiation electrode joint pad 41b ... Radiation electrode joint pad 42 ... Side wall 43 ... Sealing resin

Claims (2)

A laminated substrate formed by bonding two LTCC substrates, a first substrate and a second substrate;
Two LED elements provided with element electrodes on opposite surfaces, and
The first substrate includes a pair of die bonding pads on which each of the two LED elements is mounted and a pair of first metals formed by filling a metal in a window hole connected to each die bonding pad and penetrating in the thickness direction. Having a structure,
The second substrate includes a pair of heat radiation electrodes and a pair of second metal structures that are connected to the heat radiation electrodes and filled with metal in a window hole that penetrates in the thickness direction,
Each of the pair of die bonding pads and each of the pair of heat radiation electrodes are connected via each of the pair of first metal structures and each of the pair of second metal structures,
The first metal structure and the second metal structure connected to each other have a cross-sectional area of the second metal structure larger than a cross-sectional area of the first metal structure, and the pair of first metal structures than the spacing between the body rather is wide toward the spacing between the second metal structure of the pair,
Each of the distances is not less than 85% of the length of each pair of metal structures positioned at each distance when the length in the arrangement direction of the pair of metal structures is the same. LED light source characterized by being 85% or more of the length of the longer one when they are different . 2. The LED light source according to claim 1 , wherein the metal filling the window hole of the first substrate and the metal filling the window hole of the second substrate are both silver and a metal mainly composed of silver.

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