JPH0715152Y2 - Electronic device protection structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an electronic device such as a data carrier installed in a tool shank of a machine tool, and more specifically, to enhance protection performance for internal electronic components. Related to the protection structure of electronic devices.

(B) Prior Art Generally, in an electronic device such as a data carrier, as shown in FIG. 2, a substrate 122 having a coil portion 121 connected to a front end thereof is inserted and fixed in a coil case 123, and the surface of the substrate 122 is fixed. Each of the electronic components 124, which stores data such as processing conditions, is mounted on the back side, a protective resin layer 125 of a slightly soft silicone material such as silicon potting resin is formed on the back side to cover the back side, and wire bonding of the IC chip is performed. Protects the wire,
Further, with the outer periphery of the substrate 122 covered with the insulating sheet 126, the coil case 123 is provided with a metal case 127 and a resin case.
128 is press-fitted and fixed, and finally, an injection resin 129 such as an epoxy resin is injected from the opening end 127a of the metal case 127 to seal and fix the internal electronic components 124.

However, when used in an atmosphere such as hot and cold water that is affected by temperature changes, thermal deformation force 130 is generated due to thermal influence, as shown by a number of arrows in FIG. The injected resin 129 expands and deforms, which hinders expansion of internal electronic components, breaks the lead wires and wires that connect the internal coil, IC chip, substrate, etc., and also deforms the entire case. In some cases, the injected resin swells out from the case opening end 127a and causes a defective appearance.

To further elaborate on this point, when the above-mentioned thermal deformation force 130 is generated, since the above-mentioned protective resin layer 125 is a little soft, the protective resin layer 125 itself is deformed, and wire bonding for connecting the IC chip and the substrate. Since the wire is stressed and the wire-bonding wire is very thin, the wire is broken by the slight stress as described above. Incidentally, since the chip component on the front surface side of the substrate has a higher solder strength than the back surface, the adverse effect of the force of the injected resin does not pose a problem.

(C) Problems to be solved by the invention This invention has an expansion / contraction cushioning material layer that absorbs the deforming force of the injected resin inside the case to protect the electronic components inside and prevent deformation to the outside case. It is an object of the present invention to provide a protective structure for an electronic device that can be used.

(D) Means for solving the problems In this invention, a substrate on which electronic components are mounted on the front surface and a protective resin layer for protecting lead wires and wires of the IC chip is formed on the rear surface is placed at a predetermined position inside the case. A protective structure for an electronic device that is encapsulated with an injection resin and has a built-in expansion / contraction buffer that absorbs the effect of the thermal deformation of the injection resin on the protection resin layer between the protection resin layer and the injection resin layer. It is a protective structure for an electronic device with a material layer interposed.

(E) Action of the device According to this device, when the electronic device is used under adverse conditions where the temperature changes drastically, the injected resin inside expands thermally,
An expansion / contraction deformation force is generated, but this deformation force corresponds to expansion / contraction so as to be absorbed and avoided by the expansion / contraction cushioning layer interposed between the protective resin layer and the injection resin layer.

(F) Effect of the invention Therefore, even under use conditions affected by temperature changes, the expansion deformation force due to the injected resin does not act on the internal electronic parts and the external case, and as a result, It is possible to reliably avoid disconnection of the wire due to expansion inhibition, defective appearance of the case, etc., and it can be used as a highly reliable electronic device having a high expansion protection structure.

Further, a protective resin layer for protecting the lead wires and the wires of the IC chip is formed on the back surface of the above-mentioned substrate, and the expansion / contraction cushioning material layer is provided between this protective resin layer and the above-mentioned injected resin. That is, since the substrate is covered with the protective resin layer without being directly covered with the expansion / contraction cushioning material, the force of the injected resin is not directly transmitted to the substrate surface as stress, and the wire cutting can be avoided.

Incidentally, when the substrate is directly covered with the expansion / contraction cushioning material layer, the expansion / contraction cushioning material layer is very soft, and thus the possibility of wire cutting increases due to the force of the above-mentioned injected resin. Is impossible.

In short, in the present invention, there is no wire cutting due to the force of the injected resin, the wire can be surely protected by the above-mentioned protective resin layer, and further, stress is transmitted to the above-mentioned protective resin layer by the thermal deformation force. The effect is that the expansion / shrinkage cushioning material layer can effectively prevent this.

(G) Embodiment An embodiment of the present invention will be described in detail below with reference to the drawings.

The drawing shows a protective structure of an electronic device. In FIG. 1, the electronic device 11 includes a coil 12 for electromagnetic compatibility, a printed circuit board 14 on which electronic components 13 such as memory elements are mounted, and a housing and support for these components. The coil case 15, the metal case 16, the resin case 17, the injection resin 18 for sealing and fixing the inside of the case, and the expansion and contraction cushioning materials 19, 20 for absorbing and expanding the resin.

The above-mentioned printed circuit board 14 is connected to the ferrite core 21 incorporating the coil 12 at the front end thereof, is mounted with electronic components 13 such as storage elements for storing data such as processing conditions on the front surface, and is provided with silicon potting on the back surface. A protective resin layer 22 of resin or the like is formed to cover and protect the wiring portion on the back surface.

Further, in this case, the expansion / contraction cushioning material 19 such as polyethylene mat is attached to the entire inner surface of the ferrite core 21 with a constant thickness, and the expansion / contraction cushioning material 20 such as polyethylene mat is also provided on the outer surface of the protective resin layer 22. The expansion and contraction cushioning material is used to expand the injected resin 18 filled in the case with a fixed thickness.
I am trying to absorb at 19,20.

The printed circuit board 14 is inserted and fixed in the coil case 15, and only the coil 12 side is fitted, and the outer periphery of the non-inserted portion is covered with a water-proof insulating film 23.
Then, the metal case 16 and the resin case 17 are press-fitted and fixed, and finally, the injection resin 18 such as epoxy resin is injected from the opening end 16a of the metal case 16 to seal the electronic components 13 ...

This electronic device 11 is used as a data carrier embedded in the key groove of a tool shank used in, for example, a machine tool, and the coil 12 of the embedded electronic device 11 is required to be electromagnetically compatible with the control unit in a non-contact manner. Input / output is controlled.

The electronic device 11 configured as described above is mounted on, for example, a tool shank, and when the temperature thereof is increased by being affected by the heat of cutting, the injection resin injected inside the electronic device 11 is injected.
In proportion to this, 18 becomes high temperature and expands thermally. An attempt is made to generate an expansion deformation force according to this thermal expansion, but this thermal expansion is compressed so as to be absorbed by the expansion and contraction cushioning materials 19 and 20 layers interposed between the protective resin layer 22 and the injection resin 18 layer. Absorption is avoided to prevent expansion deformation force from occurring. In addition, the contraction action of the injected resin 18 is also absorbed by the expansion and contraction cushioning materials 19 and 20, and the contraction deformation force is avoided.

Therefore, even under use conditions affected by temperature changes, the expansion deformation force due to the injected resin 18 does not act on the internal electronic component 13 and each case 15, 16 and 17 of each part. It is possible to surely avoid wire breakage due to expansion inhibition, defective appearance of the case, etc., and it can be used as a highly reliable electronic device having an expansion circuit structure and having high protection performance.

Further, a protective resin layer 22 for protecting the lead wires and the wires of the IC chip is formed on the back surface of the above-mentioned substrate 14, and the protective resin layer 22 is formed.
A layer of expansion and contraction cushioning material 20 is provided between the above and the injection resin 18 described above. That is, the substrate 14 is not directly covered with the expansion / contraction cushioning material 20, but is covered with the protective resin layer 22.
The force of is not transmitted as stress directly to the substrate surface, and wire cutting can be avoided.

Incidentally, when the substrate is directly covered with the expansion / contraction cushioning material layer, the expansion / contraction cushioning material layer is very soft, and thus the possibility of wire cutting increases due to the force of the above-mentioned injected resin. Is impossible.

In short, in the present invention, the wire is not cut by the force of the injected resin, the wire can be reliably protected by the protective resin layer 22 described above, and the stress is transmitted to the protective resin layer 22 by the thermal deformation force. The above-mentioned expansion and contraction cushioning material 20 layer has an effect that it is possible to favorably prevent such an attempt.

[Brief description of drawings]

The drawings show one embodiment of the present invention. FIG. 1 is a vertical sectional view showing a protective structure of an electronic device, and FIG. 2 is a vertical sectional view showing a conventional protective structure of an electronic device. 11 …… Electronic equipment, 13 …… Electronic parts 14 …… Printed circuit board, 15 …… Coil case 16 …… Metal case, 17 …… Resin case 18 …… Injection resin, 19,20 …… Expansion and cushioning material 22 …… Protective resin layer

Claims (1)

[Scope of utility model registration request] 1. A protective resin layer (22) for mounting electronic components (13) on the front surface and protecting lead wires and wires of an IC chip on the back surface.
A protective structure for an electronic device, in which a substrate (14) on which is formed is sealed at a predetermined position inside a case with an injecting resin (18) and embedded, wherein the protective resin layer (22) and the injecting resin (18) layer are provided. And the protective resin layer (22) due to thermal deformation of the injected resin (18).
Protective structure for electronic devices with an expansion / contraction cushioning material (20) layer that absorbs the effects of heat.