JP2013098269A - Method for manufacturing substrate having heat dissipation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To expand a market due to the improvement of luminance deterioration and lifetime deterioration of an LED chip by providing a method for manufacturing an illumination apparatus structured to efficiently perform heat dissipation to solve the problem of preventing the propagation of LED lighting because the durability of an element is short due to the largeness of a heating value even though the LED lighting is propagating.SOLUTION: To achieve improvement of a substrate structured not to use an insulation sheet having poor thermal conductivity and heat dissipation due to a copper plate having good thermal conductivity, copper foil 3 on a glass epoxy substrate 8 and an electrode 6 of an LED chip are soldered to connect an end of the electrode to a copper plate 10 with a heat conductivity gel 12, achieving a structure that is easily subjected to heat dissipation. Heat is transferred to a radiator by avoiding the use of a resin layer as much as possible to establish a method for manufacturing an illumination apparatus structured to efficiently perform heat dissipation. The method is a method for manufacturing an LED lighting having a new glass epoxy substrate 8 with high heat dissipation.

Description

 The present invention relates to a novel substrate manufacturing method for efficiently guiding heat generated by an LED chip to a radiator.

 LED lighting is gradually becoming popular from the viewpoint of energy saving in household appliances, televisions, and commercial and industrial lighting. An aluminum substrate is widely used for the base to which the LED chip is attached. Aluminum has a high thermal conductivity after gold, silver and copper, and has a value of 236 W / mK. However, the LED substrate structure is not appropriate, impedes heat conduction, causes troubles such as a shortened life of the LED chip, destruction of circuit elements, and deterioration of solder, and durability is a problem.

Therefore, the present inventor decided to omit the insulating sheet layer, which has not been studied much, and to review the factors for improving the thermal conductivity represented by the following formula (1). The thermal conductivity k is a value indicating the ease of heat transfer, and is a numerical value indicating how much heat is transferred when the thickness of the plate-like material is 1 m and the internal / external temperature difference is 1 ° C. The larger the value, the higher the thermal conductivity.
k = W / mK (1)
Here, k is the thermal conductivity, W is the amount of heat, m is the thickness of the plate material, and K is the absolute temperature.

 In normal LED lighting, an LED chip is attached to an aluminum substrate made of a copper pattern, an insulating sheet, and an aluminum base. As shown in FIG. 1, the LED chip has its electrodes attached by soldering with a copper pattern. In the case of this structure, an insulating sheet between the copper pattern and the aluminum base is essential in order to prevent current from flowing from the LED electrode to the aluminum base. In a high power LED, the amount of heat generated is large, and if there is an insulating sheet on the aluminum base, heat transfer is hindered and the life of the LED chip is shortened. This hindered the spread of LEDs.

 Using the LED and the high heat dissipation substrate as keywords, a gazette text search was conducted for the published patent gazette and the published utility model gazette. The number of hits was 1, which was Patent Document 1. This is a technique for facilitating the movement of heat by providing a through hole or a slit-like through hole.

 A technique for bonding a high thermal conductive insulating film to a high thermal conductive substrate has been developed and published (Non-Patent Document 1). Techniques for suppressing temperature rise by performing interlayer connection with copper bumps are disclosed (Non-Patent Documents 2 and 3).

JP 2006-147333 A

OKI Technical Review April 2010 No.216 Announcement of establishment of a new company of Electrochemical Industry April 17, 2007 DENKA AGSP Corporation Homepage Basic configuration of high heat dissipation board

 Looking at the commonly used aluminum substrate, even if the thermal conductivity of aluminum is 236, the insulation sheet is sandwiched between the copper foil sheet and the aluminum substrate, so the structure cannot conduct heat. Yes. This is because a resin having a thermal conductivity of 0.2 or less must be used for insulation. The present inventor has moved away from the conventional way of thinking about the structure of the substrate, and has made it a subject to adopt a substrate with good heat dissipation, that is, excellent thermal conductivity. Further, the contact between the substrate and the radiator is poorly adhered, and if air may be contained, it similarly hinders heat conduction. In addition, the conventional aluminum substrate structure is an LED package having two insulating layers, and it is a big problem to reduce the number of insulating layers.

 As shown in FIG. 1, in the conventional technique, it has been found that an insulating layer is provided on an aluminum base, which prevents heat transfer. In order to solve this problem, one of the effects is that the chip is a bridge type, and it has been realized that the insulating layer can be omitted as shown in FIG. Instead of the copper foil 3 to be soldered, a copper plate 7 is used as shown in FIG. 2, and an aluminum base is not used, and only the solder 4 is used to short-circuit the copper plate and the electrode.

 In the structure of FIG. 2, there is a process that cannot be automated in the process of mass production, and the LED substrate of FIG. Therefore, the structure of FIG. 3 was developed to achieve high heat dissipation. That is, while maintaining the bridge structure, a copper pattern was formed under the LED electrode, and both were soldered. The aluminum substrate was changed to a glass epoxy substrate. There was an LED chip on a bridge-shaped substrate, a copper plate having a T-shaped cross section was inserted into the gap, and the LED electrode was joined with a heat conductive gel. Further, a heat conductive insulating paint was used as an adhesive for bonding the T-shaped copper plate to the substrate.

 Furthermore, in order to improve the heat dissipation, the protruding portion of the aluminum radiator with the protrusion of the structure of FIG. 4 was inserted and fixed in the hole under the chip to improve the heat dissipation.

In the case of an aluminum substrate, the LED chip rose to 68 ° C. after the lighting time at an initial temperature of 20 ° C., but in the structure of the present invention, the temperature rise was only 40 ° C. In the structure so far, heat conduction has been hindered in two places, the insulating sheet and the substrate, and the adhesive layer between the substrate and the radiator, but there is no insulating layer in the substrate, and there is only one insulating layer. It was. This is an effect that the heat transfer gel can smoothly transfer the heat to the primary radiator of the T-type copper plate having a heat conductivity of 398. At the time of joining the substrate and the heatsink, the effect of suppressing the temperature rise was born, paying attention to the adhesive resin being reduced and carefully bonding so as not to include the air layer.

Schematic diagram of conventional general LED chip mounting Schematic diagram of the current product with a copper plate as a base and with improved thermal conductivity and a bridge type LED chip. It is a schematic diagram in which a copper plate with a T-shaped cross section is fitted in the primary radiator, and is identified by solder or heat conductive gel and heat transfer paint, and the thickness of the paint is enlarged. Schematic diagram of fins installed in place of a copper plate radiator

 This will be described with reference to FIG. A copper pattern 3 is printed on a glass epoxy substrate 8 of a predetermined size, a slit hole is formed in the center of the LED mounting pattern, and a T-shaped cross-section plate protrusion, which is a copper primary radiator 10, is formed on the hole. The substrate is assembled by fitting into the hole, and the heat conductive insulating paint 11 is applied to the opposite surface of the LED chip. The LED chip is mounted on the finished substrate by soldering. The heat conductive insulating paint is kneaded with a heat conductive material selected from aluminum nitride, copper powder, heat conductive whisker, etc., and heat transfer from the LED chip of the manufactured board to the heat sink or heat dissipation case. It has a smooth structure. It is important that the solder or the insulating sheet adhesive is applied as smoothly as possible so as not to include an air layer.

 In order to carry out cooling more effectively, it is possible to further improve the heat dissipation by adopting a radiator or a heat dissipation case with protrusions as shown in FIG.

 A slit hole is made in the substrate as shown in 8 of FIG. 3 on a 1 mm-thick 30 mm × 40 mm glass epoxy substrate 3 and 4 on which the copper pattern 3 is printed, and the LED electrode 6 is soldered. After the LED chips 5 and 6 and the substrates 3 and 8 are joined to the bridge type, a copper plate 10 with a T-shaped protrusion is inserted between the bridges and the tip is hardened with a heat conductive gel 12 is adopted. .

 A slit hole is made in the substrate between the LED electrodes 6 as shown in 8 of FIG. 3 in a 1 mm-thick 30 mm × 40 mm glass epoxy substrate 3 and 4 on which the copper pattern 3 is printed. A copper plate 10 having a T-shaped protrusion is inserted and bonded with an adhesive, and an LED electrode is soldered on the completed substrate to make an LED substrate.

 As a manufacturing procedure, when the LED chip has two poles and one pole is shared with the heat radiating terminal, a hole is made on the heat radiating terminal side, the protrusion of the copper T-type primary radiator 10 is inserted, and an adhesive is used. It fixed and electrically insulating property was provided with the heat conductive insulating coating material 11.

 An LED chip is mounted on the completed substrate and completed. Thus, the heat generated from the LED chip was transferred to the copper plate by the heat conductive material of the heat conductive gel and dissipated. The heat-dissipating copper plate was fixed to the glass epoxy with a very small amount of heat conductive adhesive, and in the test, the temperature rise of the LED chip after lighting for 1 hour was suppressed to 42 ° C. An LED illuminator with good thermal conductivity was obtained.

 Until now, it has been difficult for the heat of the LED chip to be transferred to the metal plate on the back surface of the aluminum substrate. For this reason, the brightness and life of the LED chip are reduced. This has hindered widespread use. The present invention, which incorporates the omission of the insulating layer and improved heat conduction technology, can suppress the temperature rise of the LED chip, improve the durability, and expand the use for lighting in factories and theaters that require high power LEDs. I think so. Further, due to the small size of the substrate, heat can be efficiently dissipated even when heat is required other than the LED.

1 Aluminum substrate 2 Aluminum layer 2 Insulating layer 3 Copper foil layer 4 Solder layer 5 LED chip 6 LED electrode 7 Copper plate 8 Glass epoxy substrate 9 Solder 10 Copper T-type primary radiator 11 Thermal conductive insulating paint 12 Thermal conductive gel 13 Aluminum heat dissipation vessel

Claims (3)

 If the LED chip has a total of three electrodes, two electrodes and one heat dissipation electrode, on a glass epoxy substrate of a predetermined size on which a plurality of copper patterns are printed, a hole is made at the center of the heat dissipation electrode to produce the substrate. The copper plate or aluminum radiator with the T-shaped projection of the primary radiator was inserted into the hole, and the copper plate or aluminum radiator was fixed by applying heat conductive insulating paint. A method of manufacturing a heat-radiating substrate characterized by mounting and completing an LED chip using solder and a thermal conductive gel on the substrate  If the LED chip is two-pole and one pole is shared with the heat dissipation terminal on a glass epoxy board of a predetermined size printed with a plurality of copper patterns, a board is manufactured by making a hole on the heat dissipation terminal side, and in that hole Insert the copper plate or aluminum radiator with a T-shaped protrusion, and fix the copper plate or aluminum radiator by applying heat conductive insulating paint, and use solder and heat conductive gel on the finished board Manufacturing of a substrate with heat dissipation, characterized by mounting and completing an LED chip When electrical insulation is required between the tip of the T-shaped copper plate of the primary heatsink and the LED electrode, fine powders such as aluminum nitride and diamond, and when electrical insulation is not required, copper, alumina, nano 3. The method for producing an LED substrate according to claim 1, wherein the heat conduction gel is mixed with fine powder selected from carbon.