JPH0737701A - High voltage electronic component - Google Patents

Abstract

PURPOSE:To provide a small size high voltage electronic component which does not permit separation of a first resin at the boundary with an alumina substrate by covering an alumina substrate with the first insulating resin of which linear expansion coefficient is approximated to that of the alumina substrate and then packaging the first resin with a second insulating resin which has a linear expansion coefficient larger than that of the first resin and is suitable as the packaging material. CONSTITUTION:In a high voltage electronic component where a part of an electronic circuit including at least a resistor is provided on an alumina substrate 2 and the alumina substrate 2 is covered with a plurality of layers of resin 21, 4 the linear expansion coefficients of alumina substrate 2 and resins are set to become larger in the sequence from the alumina substrate 2 to the outermost resin layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high voltage electronic device such as a resistance block or a focus pack which is attached to a flyback transformer for applying a high DC voltage to a cathode ray tube of a television receiver or a display device. It is about parts.

[0002]

2. Description of the Related Art An example in which a conventional high voltage electronic component is applied to a conventionally known resistor block or focus pack will be described with reference to FIGS. Here, description of the detailed configuration of the resistance block and the focus pack is omitted.

In FIG. 5, a resistor block 1 has a substantially rectangular alumina substrate 2 in which an electric circuit (not shown) including a resistor is formed, which is covered with a first resin 3 which is an insulating resin, and the outside thereof. In addition, it was covered with the second resin 4, which is an insulating resin suitable for the exterior material.

In FIG. 6, the high voltage block 5 is composed of a focus pack 6 and a flyback transformer 7. In the focus pack 6, a substantially rectangular alumina substrate 8 having an electric circuit (not shown) is housed in a case 9 of the focus pack 6, and a first case is provided in the case 9.
It is configured by filling the resin 10 of. Next, the focus pack 6 and the flyback transformer 7 are assembled, and between the focus pack 6 and the flyback transformer 7 and in the case 11 of the flyback transformer 7, an insulating resin suitable for an exterior material is used. The second resin 12 was filled and sealed.

In this structure, the second resin 4, 12
As the epoxy resin, a crack is generated in the second resins 4 and 12 due to the strain due to the difference in linear expansion coefficient between the alumina substrates 2 and 8 and the second resins 4 and 12. . For this reason, although the coefficient of linear expansion is larger than that of the second resins 4 and 12, the first resin 3 and 10, which is an epoxy-based material that is more flexible than the second resins 4 and 12, is used as a strain buffer material for alumina. It has been used between the substrates 2 and 8 and the second resins 4 and 12.

Here, exemplifying the linear expansion coefficient of each material, that of the alumina substrates 2 and 8 is A = 7 × 10 ⁻⁶ / ° C.,
That of the first resin 3, 10 is B = 100 × 10 ⁻⁶ / ° C.,
The second resins 4 and 12 had C = 45 × 10 ⁻⁶ / ° C., and comparing the respective linear expansion coefficients, A <C <B.

[0007]

However, since the difference in the coefficient of linear expansion between the alumina substrate and the first resin coating the alumina substrate is too large, the alumina substrate and the first resin are not affected by thermal shock. There is a problem that peeling may occur at the interface, and as a result, the dielectric strength against high voltage deteriorates and the leakage current increases in the electric circuit section on the alumina substrate.

Further, when a leakage current occurs due to peeling at the interface between the alumina substrate and the first resin,
In order to satisfy the withstand voltage performance, it is necessary to widen the space between the electric circuit parts and the wiring on the alumina substrate, and there is a limit to the miniaturization of high-voltage electronic parts.

The object of the present invention is to eliminate the above-mentioned problems. After coating the alumina substrate with a first resin having a linear expansion coefficient of the insulating resin close to that of the alumina substrate, The first resin is coated with a second resin, which is an insulating resin having a large coefficient of linear expansion and suitable for a packaging material.
Another object of the present invention is to provide a small high-voltage electronic component in which the resin is not peeled off at the interface with the alumina substrate.

[0010]

Therefore, according to the structure of the present invention, at least a part of an electric circuit including a resistor is provided on an alumina substrate, and the alumina substrate is coated with a plurality of layers of resin. In the component, the coefficient of linear expansion of the alumina substrate and the resins is sequentially set to be large from the alumina substrate to the resin of the outermost layer.

[0011]

The present invention has the above-mentioned configuration,
Alumina substrate and first innermost layer covering the alumina substrate
Since the difference in the coefficient of linear expansion from the resin is small, the internal strain at the interface between the two due to thermal shock is small. Similarly, the difference in the coefficient of linear expansion between the resins from the first resin to the resin in the outermost layer is small, and the coefficient of linear expansion increases from the inside to the outside. The internal strain at the interface can be reduced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 4 by taking as an example the case where it is applied to a resistor block and a focus pack which are conventionally known high voltage electronic components. However, the same parts as those of the above-described conventional example are designated by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 1, a resistor block 20 has a linear expansion coefficient (B ') larger than that of the alumina substrate 2 having an electric circuit (not shown). Suitable for an exterior material having a linear expansion coefficient (C) larger than the linear expansion coefficient (B ′) of the first resin 21 and covered with a first resin 21 made of an insulating resin. It is configured by coating with a second resin 4 which is an insulating resin.

In FIG. 2, the high voltage block 22 comprises a focus pack 23 and a flyback transformer 7. Of these, the focus pack 23 is configured by accommodating the alumina substrate 8 having an electric circuit (not shown) in the case 9 of the focus pack 23 and filling the case 9 with the first resin 24. It Next, the focus pack 23 and the flyback transformer 7 are assembled, and the focus pack 23 and the flyback transformer 7 are assembled.
Between the flyback transformer 7 and the case 25
A second resin 12 suitable for an exterior material is filled and sealed inside.

In such a structure, the first resins 21, 2
4 and the second resin 4, 12 are made of an epoxy resin, and in order to reduce the influence of the strain generated between the alumina substrate 2, 8 and the second resin 4, 12, the first resin 21, 24
The linear expansion coefficient of the alumina substrates 2, 8 and the second resin 4, 1
A material having a linear expansion coefficient of 2 was used.

Here, the linear expansion coefficient B'of the first resin is
A <B ′ <C (however, A = 7 × 10 ⁻⁶ / ° C., C = 45
× 10 ⁻⁶ / ° C.).

Next, as another embodiment, an example in which the first resin in FIGS. 1 and 2 is replaced with a plurality of resins will be described.

3 and 4, the resistance block 30 and the high voltage block 31 have respective linear expansion coefficients B ₁ , B ₂ ,
N types of insulating resins PB ₁ , P that are B ₃ , ..., B _N
B _2, PB _3, ..., the PB _N and alumina substrate 2 and 8 second
It is used between the resins 4 and 12 of the above. Where N
Type of insulating resin _{PB 1, PB 2, PB 3} , ..., the order of coating the PB _N on the alumina substrate 2 and 8, PB _1, P
B _2, PB _3, ..., _a PB _N, the second resin 4 and 12 are disposed in the outermost layer. Then, the alumina substrates 2, 8,
The relation of the linear expansion coefficient of each material including the second resins 4 and 12 is A <B _{1 <} B ₂ <B ₃ <... <B _N <C.
The number N of insulating resins inside the N-type resin layer may be any number as long as it is 2 or more.

[0019]

According to the present invention, after the alumina substrate is coated with the first resin having the linear expansion coefficient of the insulating resin close to that of the alumina substrate, the linear expansion coefficient is larger than that of the first resin. Since the second resin, which is an insulating resin of the outer packaging material, is used for the packaging, the difference in expansion between the alumina substrate and the first resin due to thermal shock becomes small, and the first resin does not peel off at the interface with the alumina substrate, resulting in high voltage. Became more reliable. As a result, the leakage current is surely prevented on the alumina substrate, so that the circuit configuration of the alumina substrate can be made dense and miniaturized.

Further, since the difference in linear expansion coefficient between the alumina substrate and the second resin is large, by coating a plurality of kinds of materials having intermediate linear expansion coefficients from the alumina substrate side in the ascending order of linear expansion coefficient, The second outermost layer from the alumina substrate
The difference in the coefficient of linear expansion between the adjacent materials up to the resin becomes smaller, and the difference in expansion due to thermal shock also becomes smaller, and peeling at the interface between the materials can be prevented.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment in which the present invention is applied to a resistance block.

FIG. 2 is a cross-sectional view of an embodiment in which the present invention is applied to a high pressure block including a focus pack.

FIG. 3 is a sectional view of another embodiment in which the present invention is applied to a resistance block.

FIG. 4 is a cross-sectional view of another embodiment in which the present invention is applied to a high pressure block including a focus pack.

FIG. 5 is a cross-sectional view of a conventional resistance block.

FIG. 6 is a cross-sectional view of a high pressure block including a conventional focus pack.

[Explanation of symbols]

2,8 Alumina substrate 4,12 Second resin 20,30 Resistance block 21,24 First resin 22,31 High-voltage block PB ₁ , PB ₂ , ..., PB _N N kinds of resin

Claims (1)

[Claims] 1. A high-voltage electronic component in which a part of an electric circuit including at least a resistor is provided on an alumina substrate, and the alumina substrate is covered with a plurality of layers of resin. A high-voltage electronic component, wherein a coefficient of expansion is sequentially set to be larger from the alumina substrate to the resin of the outermost layer.