JPH0724297B2 - Module parts - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a module component including a heat-generating component and a component having low heat resistance.

2. Description of the Related Art In recent years, the development of module parts has been remarkable, and in the field of audio and communication represented by radio receivers, television receivers, video equipment, stereo equipment, etc., we aim to develop products with distinctive features and high added value. Therefore, it is required to be thin, lightweight and high-density.

Until now, what was used in the field of car electronics used outdoors such as automobiles and motorcycles was an accessory auxiliary device such as a radio receiver or car stereo device. Remarkably, module parts that constitute electronic circuits have come to be used up to the heart of automatic control devices and front panels.

Problems to be Solved by the Invention However, since it is necessary to mount a module component composed of a heat-generating component and a component having low heat resistance in a limited space, a high-density module component can be used as in the acoustic / communication field. It has been demanded.

By the way, the heat-generating component has a thyristor such as a power transistor and a triac, and is usually provided with a heat radiating portion. However, since heat is not sufficiently released, it is necessary to see a temperature rise of about 30 ° C. in use atmosphere temperature.

On the other hand, semiconductors such as microcomputers and ICs, which require high precision and high reliability, generate almost no heat, but the guaranteed operating temperature is often around 85 ° C, and the maximum ambient temperature in the acoustic and communication fields is 50 ° C. So it doesn't matter,
In the field used outdoors, considering the hot summer in midsummer, it is necessary to consider the maximum operating temperature as 80 ° C for a short time, but there is almost no margin in the temperature difference from the operation guaranteed temperature,
Since it is necessary to use heat-generating components and low heat-resistant components on different boards, or to mount them in a limited space where a sufficient distance cannot be secured between them, heat generated from heat-generating components can be It is necessary to insulate it so that it will not be transmitted.

In addition, when starting and operating in the cold region of winter (when heating)
High accuracy and high reliability are required even with respect to temperature stress in the vehicle and vibration during high speed driving on rough roads.

By the way, as a method of insulating a heat-resistant component from heat transmitted to a component having low heat resistance, a method of sealing with a resin or foam is generally used.

In the former method, after inserting an electronic circuit board consisting of low heat resistance parts and heat generating parts into the case, silica powder, clay,
This is a method of heat insulation by casting a resin composition in which a filler such as talc is added to a base resin such as epoxy resin, urethane resin, acrylic resin, and silicon resin. However, in consideration of workability, a large amount of filler cannot be added, so that sufficient heat insulation cannot be obtained.

The latter method of sealing with a foam is a filling part that does not need to consider the influence of foaming pressure by using a foaming urethane resin, polyethylene resin, polypropylene resin, styrene resin, etc. together with a foaming agent, accelerator, etc. Is a hollow closed system or an open system, and the resin and the foaming agent are added in units of at least several hundred g.
This is a method of mixing liquids and injecting and foaming using a spray gun or the like.

However, in the case of a module component in which an electronic circuit board is inserted in a case, the amount of foamed resin used is as small as a few g, which cannot be controlled accurately, and large stress acts on the electronic circuit board when the resin is foamed, resulting in circuit disconnection / solder. It may cause defects such as detachment.

In addition, electronic circuits have paper phenolic boards, glass epoxy boards, polyester boards, which have conductors on one or both sides.
It is composed by attaching a film with a conductor to a composite substrate or a surface-treated copper plate or aluminum plate, but the thermal conductivity of these substrates is 0.5 Kcal / mhr.
Even if the void is sealed with a resin having a high temperature of about 0 ° C. and low thermal conductivity, heat is transmitted through the substrate, and sufficient heat insulation cannot be obtained.

By the way, if it is an accessory auxiliary device such as a radio receiver or car stereo device, it may be allowed even if there is some malfunction beyond the guaranteed temperature, but it is a module part used at the heart of car electronics. The conditions required for are severe, and even a slight malfunction can cause personal injury, so high precision and reliability are required.

Means for Solving Problems A heat-resistant film attached to a substrate made of a resin foam with a thermal conductivity of 0.05 Kcal / m · hr · ° C or less and having a patterned conductor formed on at least a heat-generating component and a heat-resistant material. The above problem is solved by forming an electronic circuit composed of low components and inserting the substrate surface so as to face the substrate.

By the way, for a substrate made of a resin foam having a thermal conductivity of 0.05 Kcal / m · hr · ° C or less, the foam obtained by block-foaming a foamable urethane resin, polypropylene resin, phenol resin, or the like is used. It can be easily obtained by cutting it according to the dimensions of the case and attaching it to a heat-resistant film using double-sided adhesive tape or adhesive.
A slit may be provided on the substrate.

Further, the heat resistant film and the foam can be laminated using a continuous laminator.

It is also possible to further improve the heat insulating properties of the two by using a surface-treated metal plate having good thermal conductivity such as copper or aluminum for the case material of the heat generating component mounting surface.

Action The action of this technical means is as follows. That is, by using a substrate made of a resin foam having excellent heat insulation, heat conduction through the substrate is eliminated, and
By forming an electronic circuit including at least a heat-generating component and a component having low heat resistance on a heat-resistant film on which a conductor having a pattern is formed, and inserting the substrate so that the substrate surfaces face each other, the heat from the heat-generating component is made into a resin foam. Since it is heat-insulated by the substrate consisting of and has cushioning properties, it is possible to obtain a module component with high accuracy and high reliability that is excellent in temperature stress and vibration resistance.

Example Hereinafter, a module component of an example of the present invention will be described in detail with reference to the drawings.

Example 1 In FIG. 1, a polyimide film 2 having an electronic circuit pattern was attached to a substrate 1 made of a phenolic foam having slits with a thermal conductivity of 0.020 Kcal / m · hr · ° C. using a double-sided adhesive tape, An electronic circuit board to which a triac 3 having a heat radiating portion, a chip type fixed resistor 4, and a microcomputer 5 was attached was inserted into a case 6 made of heat-resistant ABS resin with the surface on the side of the board 1 facing.

The module parts produced as described above were normal without any malfunction even when operated in a constant temperature bath at 80 ° C. In addition, a thermal shock test of 100 cycles for -40 ℃ x 30 minutes and + 85 ℃ x 30 minutes
It was normal when the characteristics were evaluated later.

Example 2 In FIG. 2, after a substrate 7 made of urethane foam having a heat conductivity of 0.035 Kcal / m · hr · ° C and a polyimide film 2 having an electronic circuit pattern are attached using a continuous laminator, Power transistor 8 with
The electronic circuit board to which the semiconductor element 9 is attached is mounted on the case in which the positioning protrusion 11 is provided on the aluminum plate 10 on which the surface on which the power transistor 8 is mounted is anodized and the other surface is made of phenol resin 12 Inserted with the side faces facing each other.

The module parts created as described above are the same as those in Example 1.
The characteristics were normal even when the same operation test and thermal shock test were performed in a constant temperature bath at 80 ℃.

EFFECTS OF THE INVENTION As is apparent from the above description, the module component according to the present invention eliminates heat conduction through the substrate and forms a conductor having a pattern by using a substrate made of a resin foam having excellent heat insulating properties. By forming an electronic circuit consisting of at least a heat-generating component and a component having low heat resistance in the heat-resistant film, and inserting the heat-resistant component into the case with the substrate surface facing each other, heat from the heat-generating component is insulated by the substrate made of resin foam. Since it has cushioning properties, it has excellent temperature stress and vibration resistance, and we were able to obtain highly accurate and highly reliable module parts.

[Brief description of drawings]

FIG. 1 is a sectional view of a module part according to a first embodiment of the present invention, and FIG. 2 is a sectional view of a module part according to a second embodiment of the present invention. 1 ... Phenolic foam substrate, 2 ... Polyimide film, 3 ... Triac, 4 ... Fixed resistor, 5 ... Microcomputer, 6 ... Heat-resistant ABS case, 7 ...
… Urethane foam substrate, 8 …… Power transistor,
9 ... Semiconductor element, 10 ... Aluminum plate, 11 ... Positioning protrusion, 12 ... Phenolic resin.

Claims (1)

[Claims] 1. A heat-resistant film having a conductor having a pattern formed on the outer surface of a single U-shaped substrate made of resin foam having a thermal conductivity of 0.05 Kcal / m · hr · ° C. or less. A module component, wherein an electronic circuit including at least a heat-generating component and a component having low heat resistance is formed on the heat-resistant film, and a substrate having the electronic circuit is inserted into a case.