JP2006019557A - Light emitting device, its mounting method, lighting apparatus and display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high quality light emitting device, its mounting method, a lighting apparatus and a display for simply realizing highly efficient heat radiation with a small space, for stabilizing the output or light emission wavelength of a light emitting element, for improving the reliability of the light emitting element, and for lengthening the life of the light emitting element. <P>SOLUTION: In a light emitting device where the die bonding and wire bonding of a plurality of light emitting elements 20 is carried out on a substrate 10; a plurality of recesses 11 are formed on a substrate upper face 10b, the die bonding and wire bonding of each light emitting element 20 is carried out in each recess 11, and a groove 12 for heat radiation is formed on a substrate back face 10b. A heat pipe 30 is formed so as to be butted in each groove 12. The cross-section of the heat pipe 30 is formed so as to be shaped like an ellipse. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light emitting device using a light emitting element, a mounting method thereof, a lighting fixture, and a display, and more particularly to a heat dissipation mechanism of the light emitting element.

  2. Description of the Related Art Light emitting devices such as lighting fixtures and displays are known that use LEDs (Light Emitting Diodes) as light emitting elements. In such a light-emitting device, when mounting a plurality of LEDs, roughly divided, a method in which LEDs molded with resin are arranged on a plane, an LED chip is placed on a substrate, electrodes are connected, and a resin is formed from above. The method of molding with is known. Among these, the latter is envied for the future from the viewpoint of lightening and integration.

  However, the latter, in particular, has a problem in that the heat generated from the light emitting element is poor in heat dissipation, causing a temperature rise in the entire device. For this reason, the LED chip itself, which is a light emitting element, also rises in temperature and changes in output. In addition, there is a problem in that changes in wavelength and chromaticity occur. Furthermore, there existed a problem that the reliability as LED and the lifetime became short.

In order to solve such a problem, a method of arranging LEDs molded with resin on a plane, a heat-radiating sheet in close contact with a substrate, and a structure comprising a heat-dissipating member in close contact with the heat-dissipating sheet and provided with a fin portion (Refer patent document 1) and the method (refer patent document 2) which thermally radiates also from a main body case in addition to a radiation fin are proposed.
JP-A-8-50458 JP 2001-44517 A

  However, in the conventionally proposed method, the air around the heat radiating fins is warmed, and the heat radiating efficiency is not sufficient. In particular, in these methods, the LED chip is placed on a substrate and then molded with a resin from the LED chip, the heat dissipation is not sufficient, and the above-described problem is prominent.

  The present invention has been made in view of the above problems, and realizes heat radiation with high efficiency in a simple and small space, stabilizes light emitting element output and emission wavelength, improves reliability as a light emitting element, and has a long lifetime. An object of the present invention is to provide a high-quality light-emitting device that can be realized, a mounting method thereof, a lighting fixture, and a display.

  To achieve the above object, a light-emitting device according to claim 1 is a light-emitting device in which a plurality of light-emitting elements are die-bonded and wire-bonded on a substrate, and a plurality of recesses are provided on one surface of the substrate. The light emitting element is die-bonded and wire-bonded in each of the recesses, and a heat radiating groove is provided on the other surface of the substrate.

  The light emitting device according to the invention of claim 2 is characterized in that a heat pipe is provided on the other surface of the substrate.

  The light emitting device according to the invention of claim 3 is characterized in that the heat pipe is provided in contact with the heat radiating groove.

  The light emitting device according to the invention of claim 4 is characterized in that the cross section of the heat pipe is elliptical.

  The light emitting device according to the invention of claim 5 is characterized in that the heat pipe also serves as electrical wiring of the light emitting element.

  The light emitting device according to the invention of claim 6 is characterized in that the light emitting element is an LED.

  The light-emitting device mounting method according to claim 7 is a light-emitting device mounting method in which a plurality of light-emitting elements are die-bonded and wire-bonded on a substrate, and a plurality of recesses are provided on one surface of the substrate and heat is released on the other surface. And a step of die-bonding and wire-bonding the plurality of light-emitting elements in each of the recesses.

  The light emitting device mounting method according to claim 8 further includes a step of providing a heat pipe on the other surface of the substrate.

  The light emitting device mounting method according to claim 9 is characterized in that, in the step of providing the heat pipe, the heat pipe is provided in contact with the heat radiating groove.

  The light emitting device mounting method according to claim 10 is characterized in that the cross section of the heat pipe is elliptical.

  The light emitting device mounting method according to claim 11 is characterized in that the heat pipe also serves as an electrical wiring of the light emitting element.

  The light emitting device mounting method according to claim 12 is characterized in that the light emitting element is an LED.

  A lighting fixture according to a thirteenth aspect uses the light-emitting device according to any one of the first to sixth aspects.

  A display according to a fourteenth aspect uses the light emitting device according to any one of the first to sixth aspects.

  According to the invention of claim 1, 7, 13 or 14, the light emitting element is placed on the concave portion provided on the upper surface of the substrate, and the heat radiating groove is provided on the back surface of the substrate. Heat can be radiated easily and efficiently through a heat radiating groove with a large surface area, and it is not necessary to use a space like a heat radiating structure using a Peltier element or a heat sink, so it can be further downsized. . This makes it possible to achieve high-efficiency heat dissipation easily and in a small space, stabilize the output and emission wavelength of the light-emitting element, improve the reliability as a light-emitting element, and extend the life of the light. An apparatus can be provided.

  According to invention of Claim 2, 8, 13 or 14, since the heat pipe was provided in the back surface of a board | substrate, in addition to the said effect, the heat | fever emitted from the light emitting element can be thermally radiated more simply and efficiently.

  According to the invention of claim 3, 9, 13 or 14, since the heat pipe is provided in contact with the heat radiating groove, in addition to the above effects, the heat pipe can be assembled more simply by fitting it into the groove. Therefore, the heat generated from the light emitting element can be radiated more easily and more efficiently.

  According to the invention described in claim 4, 10, 13 or 14, since the cross section of the heat pipe is formed in an elliptical shape, in addition to the above effect, it is possible to ensure a larger surface area in contact with the back surface of the substrate, and a complicated structure Therefore, the heat generated from the light emitting element can be radiated more easily and with higher efficiency.

  According to the invention of claim 5, 11, 13, or 14, since the heat pipe also serves as the electric wiring of the light emitting element, in addition to the above effects, heat generated from the light emitting element can be radiated more directly. In addition, since the electrical wiring of the light emitting element can be omitted, the wiring structure can be simply constructed, the number of processes can be reduced, and the space can be reduced more effectively.

  According to the invention of claim 6, 12, 13 or 14, since the light emitting element is an LED, the above effect is maximized, the output of the LED and the emission wavelength are stabilized, and the reliability as the LED is improved. Improvement and longer life can be further achieved.

  The best mode for carrying out a light-emitting device and a mounting method thereof according to the present invention will be described below with reference to the accompanying drawings.

  1 and 2 are schematic perspective views of the light emitting device of this embodiment.

  The light-emitting device shown in FIG. 1 is formed by placing a plurality of light-emitting elements 20... 20 made of LED chips (semiconductor chips) on a substrate 10, connecting each electrode, and then molding the resin with resin. It is.

  In order to improve the reflectivity of the substrate 10, it is desirable that at least the upper surface (one surface) 10 a of the substrate 10 has a highly reflective white or metallic luster, and the whole is made of a material having good thermal conductivity. Ceramics etc. are illustrated as a material with these characteristics. In this substrate 10, a plurality of recesses 11... 11 in which the light emitting elements 20... 20 are arranged are formed on the substrate upper surface 10 a, and a plurality of heat radiations for increasing the surface area are provided on the substrate rear surface (the other surface) 10 b. Grooves 12... 12 are respectively formed.

  The concave portions 11... 11 are two-dimensionally arranged at predetermined intervals on the substrate upper surface 10a along two vertical and horizontal directions orthogonal to the substrate 10 (hereinafter referred to as “XY directions” according to the example in the figure). Is formed. The wall surface of each of the recesses 11... 11 is formed along a direction perpendicular to the substrate upper surface 10a (hereinafter referred to as “Z direction” according to the example in the drawing). Each light emitting element 20 ... 20 is die-bonded and wire-bonded to the bottom of each recess 11 ... 11, and is molded with a resin (not shown).

  The grooves 12... 12 are formed to extend in the Y direction at periodic positions on the substrate back surface 10 b facing the recesses 11... 11 arranged in the X direction on the substrate upper surface 10 a. The wall surface of each groove | channel 12 ... 12 is formed along the Z direction. In each groove 12... 12, a plurality of heat pipes 30... 30 are attached in order to further improve the heat dissipation performance with respect to the heat generated from the light emitting elements 20.

  Each of the heat pipes 30 ... 30 is composed of a pipe composed of a thin tube and a heat transport fluid enclosed in the thin tube, and effectively transfers heat from the high temperature portion to the low temperature portion by a cycle of evaporation and condensation. . The fluid warmed in the high-temperature part moves to the low-temperature part and condenses in the low-temperature part, and the condensed fluid moves to the high-temperature part by transferring the core material called wick using capillary action. . In this embodiment, the heat pipe 30 has an elliptical cross-sectional shape. However, the present invention is not limited to this, and other shapes such as a circular shape, a flat shape as shown in FIG. It may be.

  In the light emitting device shown in FIG. 1, the wall surfaces of the recesses 11 and the grooves 12 are both formed in a direction perpendicular to the substrate 10 (Z direction), that is, linear, but the wall shape is not limited to this, and FIG. As shown in the light-emitting device shown, each wall surface of the recess 11 and the groove 12 is angled for the purpose of irradiating in a desired direction (upward) with higher efficiency and matching the shape of the heat pipe that is easy to produce. The wall surface shape may be a curve (eg, an ellipse).

  In the light-emitting device shown in FIG. 2, the wall surfaces of the recesses 11... 11 are irradiated from the light-emitting elements 20. It is formed to spread in. Moreover, the wall surface of each groove | channel 12 ... 12 is formed in the ellipse shape according to the cross-sectional shape of the heat pipe 30 in order to improve heat dissipation.

  FIG. 3 is a schematic cross-sectional view of the vicinity of the light emitting element 20 of the light emitting device shown in FIG.

  As shown in FIG. 3, conductor layers 40 are patterned on the bottom surface of the recess 11 of the substrate top surface 10a. The conductor layer 40 is printed with a metal such as Ag or W, and is subjected to Au plating for the purpose of improving adhesiveness. The light emitting element 20 is bonded to the conductor layer 40 with an adhesive or the like, and the electrodes (positive electrode and negative electrode) of the light emitting element 20 are electrically conductive from a wire such as a gold wire or the back surface of the light emitting element 20 depending on the structure of the light emitting element 20. It is electrically connected to the electrodes (positive electrode and negative electrode) of the conductor layer 40 via a conductive adhesive on the body layer 40. The conductor layer 40 is formed on the substrate back surface 10b via two through-holes (or via holes) 41 and 41 for positive and negative electrodes that penetrate the bottom surface of the recess 11 and the substrate back surface 10b in a substantially vertical direction (Z direction). The positive and negative wiring terminals 42 and 42 are electrically connected.

  4 is a schematic perspective view for explaining a mounting method for assembling the light emitting device shown in FIG. 2, and FIG. 5 is a schematic perspective sectional view of the entire light emitting device after being assembled by the method shown in FIG.

  As shown in FIGS. 4 and 5, the light emitting device mounting method is formed by forming each recess 11... 11 on the substrate upper surface 10 a and a plurality of heat radiation grooves 12. Each light emitting element 20 ... 20 is die-bonded and wire-bonded in each recess 11 ... 11 and then resin-molded, and a plurality of heat pipes 30 ... 30 are provided in contact with each formed groove 12 ... 12. Process. Here, both ends of each of the heat pipes 30 ... 30 are connected to two heat pipes 31, 31 extending in the X direction of the substrate 10, respectively, as shown in FIG.

  Through the above steps, the wall shape of each groove 12... 12 is formed in a curved shape so as to match the cross-sectional shape of each heat pipe 30... 30, that is, an ellipse, and in each groove 12. 30 ... 30 are inserted.

  According to this, each heat pipe 30 ... 30 which consists of a thin tube and the heat transport fluid enclosed in this thin tube is thermally couple | bonded with the light emitting element 20, and dissipates the heat emitted from the light emitting element 20 effectively. be able to. Further, by preparing the shapes of the grooves 12... 12 of the substrate back surface 10 b in advance so as to match the shapes of the heat pipes 30, it is easy to simply fit the heat pipes 30 into the grooves 12. High heat dissipation can be obtained.

  Therefore, according to the present embodiment, the concave portion 11 on which the light emitting element (LED chip) 20 is placed is provided on the substrate upper surface 10 a in advance, and the substrate 10 in which the groove 12 is provided on the substrate rear surface 10 b is manufactured. 20 is die-bonded and wire-bonded, resin-molded from above, and the heat pipe 30 is fitted into the groove 12 so that heat generated from the light-emitting element 20 can be easily and efficiently dissipated without taking a complicated structure. can do.

  In particular, in this embodiment, since the distance from the light emitting element 20 that is a heat source to the heat pipe 30 that dissipates heat is short, the effect is great. Further, according to the present embodiment, there is an advantage that no space is required unlike the method using a Peltier element or a heat sink.

  The heat pipe of the above embodiment is a pipe enclosing a heat transport fluid, but since the surface of the pipe is usually a metal, the heat pipe is used as the electrical wiring of the light emitting element by flowing electricity to the surface of the pipe. A method is conceivable. The light emitting device of this example uses this method.

  FIG. 6 is a schematic cross-sectional view of the vicinity of the light emitting element 20 when the heat pipes 30... 30 are also used as wirings in the light emitting device of this embodiment. This basic structure is the same as in FIG. 5 described above, but the positions of the two through holes (or via holes) 41 and 41 for the positive electrode and the negative electrode are different in order to make the heat pipe 30 and the conductor layer 40 conductive. As shown in FIG. 6, the recess 11 is formed so as to penetrate in an oblique direction between the two wall surfaces in the X direction of the recess 11 and the wall surfaces of the two grooves 12, 12 adjacent to the recess 11 at a predetermined angle.

  FIG. 7 is a schematic perspective view for explaining a mounting method for assembling the light emitting device shown in FIG.

  As shown in FIG. 7, when the heat pipe 30 also serves as an electrical wiring, it is necessary to alternately provide two types of heat pipes 30a... 30a and 30b. The direction of the positive electrode and the negative electrode is opposite to the tip 20. The positive heat pipes 30a to 30a have a structure in which one end is connected to the positive heat pipe 31a extending in the X direction and the other end is not connected to any of them. Similarly, the negative electrode heat pipes 30b to 30b are connected to the positive electrode heat pipe 31b extending in the X direction, and the other end is not connected to any of them. According to this, since the heat generated from the light emitting element 20 can be directly radiated, the heat can be radiated with higher efficiency.

  Therefore, according to the present embodiment, in addition to the same effects as those of the first embodiment, the heat pipe 30 also serves as the electrical wiring of the light emitting element 20, so that the heat generated from the light emitting element 20 is directly radiated. be able to.

  As described above, the present invention can be applied to a light-emitting device using a plurality of light-emitting elements (LEDs) such as a lighting fixture and a display.

1 is a schematic perspective view of a light emitting device according to Example 1 of the present invention. It is a schematic perspective view of the light-emitting device when the wall surface shape of the recess on the upper surface of the substrate and the groove on the back surface of the substrate is changed. It is a cross-sectional schematic diagram of the light emitting element vicinity of the light-emitting device shown in FIG. It is a schematic perspective view explaining the mounting method of the light-emitting device shown in FIG. It is a schematic perspective view of the light-emitting device assembled by the mounting method shown in FIG. It is a cross-sectional schematic diagram of the light emitting element vicinity of the light-emitting device which concerns on Example 2 of this invention. It is a schematic perspective view explaining the mounting method of the light-emitting device shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Substrate 10a Substrate upper surface 10b Substrate back surface 11 Recess 12 Groove 20 Light emitting element 30, 31 Heat pipe 40 Conductor layer 41 Through hole (or via hole)

Claims (14)

In a light emitting device in which a plurality of light emitting elements are die bonded and wire bonded on a substrate,
A plurality of recesses are provided on one surface of the substrate,
The light emitting element is die-bonded and wire-bonded in each recess,
A light emitting device, wherein a heat radiating groove is provided on the other surface of the substrate.   The light-emitting device according to claim 1, wherein a heat pipe is provided on the other surface of the substrate.   The light emitting device according to claim 2, wherein the heat pipe is provided in contact with the heat radiating groove.   The light-emitting device according to claim 2, wherein a cross section of the heat pipe is elliptical.   The light-emitting device according to claim 2, wherein the heat pipe also serves as an electrical wiring of the light-emitting element.   The light emitting device according to claim 1, wherein the light emitting element is an LED. In a mounting method of a light emitting device in which a plurality of light emitting elements are die bonded and wire bonded on a substrate,
Forming a plurality of recesses on one surface of the substrate and a heat dissipation groove on the other surface;
And a step of die bonding and wire bonding the plurality of light emitting elements in each of the recesses.   The light emitting device mounting method according to claim 7, further comprising a step of providing a heat pipe on the other surface of the substrate.   9. The light emitting device mounting method according to claim 8, wherein the step of providing the heat pipe includes providing the heat pipe in contact with the heat radiating groove.   The light emitting device mounting method according to claim 8, wherein a cross section of the heat pipe is elliptical.   The method for mounting a light emitting device according to claim 8, wherein the heat pipe also serves as an electrical wiring of the light emitting element.   The light emitting device mounting method according to claim 7, wherein the light emitting element is an LED.   The lighting fixture using the light-emitting device of any one of Claims 1 thru | or 6. A display using the light-emitting device according to claim 1.

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