JP2002203708A - High-voltage resistor unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-voltage resistor unit which is small in size, excellent in withstand voltage properties, and high in reliability. SOLUTION: A high-voltage resistor unit is equipped with a ceramic board 10 provided with resistors 12 and an electrode 11 on its front surface, and the ceramic board 10 is covered with a resin coating layer 17. A slit groove 15 is cut in the surface of the ceramic board 10 between the resistors 12 or between the resistor 12 and the electrode 11, and the resin coating layer 17 fills partly in the slit groove 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focus pack for adjusting a focus voltage of a television receiver, a display monitor, or the like, and a high-voltage resistor used for a high-voltage power supply or the like.

[0002]

2. Description of the Related Art Hitherto, a high-voltage variable resistor called a focus pack has been widely used for adjusting a focus voltage of a television receiver, a display device or the like. As a part of such a high-voltage variable resistor or a high-voltage power supply, a bleeder resistor having a structure in which a resistor and an electrode are formed on a ceramic substrate and the periphery of the ceramic substrate is covered with a resin coating layer is used. ing.

[0003] The withstand voltage performance of such a bleeder resistor is ensured by the adhesion between the ceramic substrate and the resin coating layer. However, the strain stress of the resin increases due to the difference in the coefficient of thermal expansion between the ceramic substrate and the resin, so that peeling and cracking tend to occur between the ceramic substrate and the resin. If resin peeling or cracking occurs, discharge breakdown may occur due to high voltage during operation.

[0004]

As shown in FIG. 1, a high-voltage resistor having a plurality of concave and convex portions formed around a ceramic substrate to prevent a discharge accident or a failure due to such peeling or cracking. It has been proposed (JP-A-64-5)
No. 5804). In the figure, 1 is a ceramic substrate, 2 is an electrode, and 3 is a resistor. A notch 4 as shown in FIG. 4A and a concave groove 5 as shown in FIG. 5B are formed in the peripheral portion of the ceramic substrate 1.
Coated with.

However, even if the uneven portions 4 and 5 are provided on the peripheral portion of the ceramic substrate 1 as described above, it hardly contributes to the improvement of the adhesion between the surface of the ceramic substrate 1 and the resin 6. The characteristics are not always improved. In addition, special processing is required for the ceramic substrate 1 in order to provide the concave and convex portions 4 and 5, which may cause an increase in processing cost.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a high-voltage resistor having a small size, excellent withstand voltage performance, and high reliability.

[0007]

According to the present invention, there is provided a ceramic substrate having a resistor and an electrode formed on a surface thereof, and a resin coating layer formed on at least the surface of the ceramic substrate on which the resistor is formed. In the formed high-voltage resistor, a slit groove is formed on the surface of the ceramic substrate, between the resistors, between the electrodes, or between the resistor and the electrode, and the slit groove is formed of the resin coating layer. Provided is a high-voltage resistor characterized in that a part thereof enters.

In the present invention, between the resistors of the ceramic substrate,
A slit groove is formed in a portion having a potential difference, such as between the electrodes and between the resistor and the electrode, and a part of the resin coating layer enters the slit groove. The withstand voltage performance of the resin-coated high-voltage resistor is determined by the creeping withstand voltage performance of the ceramic substrate surface, and is greatly affected by the adhesion between the ceramic substrate and the resin. By providing a slit groove in a portion of the surface of the ceramic substrate where there is a potential difference, the surface of the ceramic substrate becomes three-dimensional, and resin enters into this portion, which changes from a simple flat surface withstand voltage to a three-dimensional insulating structure, The withstand voltage performance is greatly improved. Further, the resin is hardly affected by the adhesion performance of the resin itself, the characteristics are stabilized, and the reliability is improved. As described above, since the withstand voltage performance is improved by the resin entering the slit groove, the resistor and the electrode can be arranged at a short distance, and the size of the resistor can be reduced. The slit groove of the present invention only needs to ensure a creepage distance and does not need to be a deep groove, so that the strength of the ceramic substrate hardly decreases.

It is desirable that the slit groove is formed by laser processing. In the case of laser processing, since a groove can be formed after a resistor or an electrode is formed on a ceramic substrate, special processing such as conventional drilling or cutting is unnecessary, and it is inexpensive.

It is preferable that the depth of the slit groove is not more than 1/10 of the thickness of the ceramic substrate. This is because if the depth of the slit groove is 1/10 or more of the thickness of the ceramic substrate, the strength of the ceramic substrate is reduced, and the ceramic substrate may be broken by the curing shrinkage stress of resin.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A high-voltage resistor according to an embodiment of the present invention will be described with reference to FIGS. This high-voltage resistor shows an example of a bleeder resistor used for a high-voltage power supply.

The high-voltage resistor includes a rectangular ceramic substrate 10 made of alumina or the like. A pair of electrodes 11 made of silver or the like is formed at both ends of the surface, and a meandering resistor 12 is formed therebetween. I have. The pattern of the resistor 12 is not limited to the shape shown in FIG. The above electrode 11
The resistor 12 is printed on the ceramic substrate 10 and fired. The resistor 12 is covered with a protective layer 13 made of a glass material. Solder 14 is placed on electrode 11
Is connected to the lead terminal 16.

The surface of the ceramic substrate 10
A thin slit groove 15 is provided between portions where a potential difference occurs, such as between the resistor 12 and between the resistor 12 and the electrode 11.
Are formed. In particular, a plurality of slit grooves 15 are formed in a portion having a large potential difference (for example, between the resistor 12 and the electrode 11). These slit grooves 15 are formed by laser processing, and preferably have a depth of 10 to 30 μm and a width of 40 to 60 μm. It is preferable that the depth of the slit groove 15 be 1/10 or less of the thickness of the ceramic substrate 10 because a decrease in the strength of the ceramic substrate 10 can be prevented.

In this embodiment, one end of the slit groove 15 extends to the side edge of the ceramic substrate 10, but it does not necessarily need to be formed to the side edge. The periphery of the ceramic substrate 10 is dip-coated with an insulating resin coating layer 17 such as an epoxy resin. Part of the resin coating layer 17 also enters the slit groove 15.

In the high-voltage resistor having the above configuration,
As shown in FIG. 3, the provision of the slit groove 15 increases the creepage distance and increases the withstand voltage between the end (point A) of the electrode 11 and the end (point B) of the resistor 12. It is improved by the insulating resin 17 entering the groove 15. Then, the adhesive strength between the ceramic substrate 10 and the resin coating layer 17 increases due to the wedge effect of the resin entering the slit groove 15, and the ceramic substrate 10 and the resin coating layer 17
And the occurrence of cracks between them can be prevented. Therefore, discharge breakdown due to high voltage during operation can be prevented.

Since the slit groove 15 improves the withstand voltage performance between the electrode 11 and the resistor 12 and between the resistor 12, the resistor 12 and the electrode 11 can be arranged at a short distance, and the The size of the resistor can be reduced.
For example, in the case of a high voltage resistor having a planar withstand voltage structure of 6 kV / mm, a slit groove 15 having a width of 50 μm is used.
By forming, the withstand voltage can be improved to about 30 kV / mm, and the withstand voltage performance can be improved about 5 times. In addition, since it is hard to be affected by the adhesion performance of the resin material, the withstand voltage performance is stabilized and the reliability is improved. That is, even if material variations and processing variations occur, the influence of these variations on quality can be reduced. Since the slit groove 15 can be processed by laser,
Higher mass productivity and lower processing costs compared to conventional drilling and cutting processes. Moreover, since the width of the slit groove 15 is very small, the strength of the ceramic substrate 10 does not decrease.

FIG. 4 shows a second embodiment of the present invention. This embodiment shows an example of a fixed resistor of a high-voltage variable resistor. The fixed resistor 20 includes a film resistor 22 forming a top bleeder resistor and a film resistor 2 forming a detection resistor on one main surface of a ceramic substrate 21 made of alumina or the like.
3, 24 are formed. The film resistor 24 is formed in a substantially square shape so as to have a very small resistance value. One end of the film resistor 22 and the film resistor 23 is connected to the terminal electrode 25a, and the other end of the film resistor 22 is connected to the terminal electrode 2a.
5b, and the other end of the film resistor 23 is connected to the film resistor 24. The connection point between the film resistor 23 and the film resistor 24 is connected to the terminal electrode 25c, and the other end of the film resistor 24 is connected to the terminal electrode 25d. Lead wires 26a, 26b, 26c, 26d are attached to the terminal electrodes 25a, 25b, 25c, 25d by soldering, respectively, and a resin coating layer 27 of epoxy resin or the like is coated so as to cover the entire ceramic substrate 21. ing.

In this embodiment, the terminal electrodes 25c and 25c
Since d is formed at a close position, a slit groove 28 is provided on the surface of the ceramic substrate 21 therebetween. By inserting the resin coating layer 27 into the slit groove 28, the withstand voltage performance between the electrodes 25c and 25d can be improved.

FIGS. 5 to 7 show a third embodiment of the present invention, in which a high-voltage resistor is used as a variable resistor of a top load focus pack. As shown in FIG. 5, the focus pack includes a case 30 made of an insulating resin having a substantially rectangular frame-like side wall and a bottom wall. A resistance substrate 31 made of a ceramic such as alumina is accommodated in the case 30 with its surface facing the bottom wall of the case 30. Fixed. Bearing portions 32, 33 are provided on the bottom wall of the case 30, and these bearing portions 32, 33 are provided with sliders 34a, 35a, respectively.
Are mounted on the rotating shafts 34 and 35.

A resin 36 is molded in the opening of the case 30 so as to cover the back side of the resistance substrate 31, and a part of the molding resin 36 also reaches the front side of the resistance substrate 31. That is, the partition wall 3 is provided on the bottom wall of the case 30.
7, the partition wall 37 is in contact with the surface of the resistance substrate 31, and regulates the mold resin 36 from entering the room in which the rotating shafts 34 and 35 are accommodated. As described above, the partition wall 37 separates the high-pressure portion resin-molded from the variable resistance portion not resin-molded (see FIG. 7).

Further, a rib 38 which comes into contact with the surface of the resistance substrate 31 is integrally protruded from the bottom wall of the case 30 in which the rotating shafts 34 and 35 are accommodated. As shown in FIG. 6, the space between the ribs 38 and the resistance substrate 31 is fixed by a coating resin 39 as an adhesive. The rib 38 is formed at a position corresponding to a slit groove 55 provided on the resistance substrate 31 described later, and has a length substantially transverse to the resistance substrate 31 (see FIG. 7). Therefore, the resistance substrate 3 due to the repulsive force of the sliders 34a, 35a
1 is prevented.

As shown in FIG. 7, a meandering high-voltage-side resistor portion 40 is formed on the surface of the resistor substrate 31, and the surface of the resistor portion 40 is covered with a protective layer 41 made of a glass material.
Further, it is covered with the mold resin 36 from above. The terminating end of the resistor section 40 is connected to a screen voltage adjusting variable resistor section 43 via an arc-shaped focus voltage adjusting variable resistor section 42. Further, the resistance substrate 3
1 has a center electrode 44 for focus voltage adjustment at the center of the variable resistor 42 and the center of the variable resistor 43.
And a center electrode 45 for adjusting the screen voltage. Note that the variable resistance portions 42 and 43 and the center electrode 4
4 and 45 are not covered with the glass protective layer 41 or the mold resin 36. Slider 34a attached to rotating shaft 34
Contacts across the center electrode 44 and the variable resistance section 42,
The slider 35a attached to the rotating shaft 35 has the center electrode 4
5 and the variable resistance portion 43 are straddled, and the resistance value can be varied by sliding on the variable resistance portions 42 and 43, respectively.

The starting end of the resistor portion 40 and the center electrodes 44 and 4
5, terminal electrodes 46 to 49 are provided at one end and the variable resistor 43, respectively.
Lead terminal 50 penetrating resistor substrate 31 and extending to the back side
The lead terminals 50 to 53 project from the molding resin 36.

On the resistance substrate 31, a resistor portion 40 and an electrode 4
6, and between the resistor portions 40.
Are provided, and the mold resin 36 is embedded in these slit grooves 54. A slit groove 55 is also provided between the variable resistance section 42 and the variable resistance section 43, and the rib 38 and the resistance substrate 31 are bonded and fixed to the slit groove 55 as shown in FIG. The coating resin 39 is embedded. Thus, the slit groove 5
When the resins 36 and 39 enter the 4, 55, the structure is obtained by combining the withstand voltage of the resin with the simple withstand voltage, and the withstand voltage characteristic of the surface of the resistance substrate 31 is greatly improved.

In the third embodiment, the mold resin 36 is formed so as to cover the back surface of the resistor substrate 31 and a part of the surface (resistor portion 40) which is a high voltage portion.
May cover only the back surface of the resistor substrate 31, and the resistor portion 40 of the resistor substrate 31 may be coated with a resin different from the mold resin 36.

In the above embodiment, the linear slit grooves are provided between the resistors, between the electrodes, and between the electrodes and the resistor. However, the slit grooves need not be linear, but may be curved. Is also good. The processing method of the slit groove is not limited to the method using a laser, and another method may be used. As the resin material constituting the resin coating layer of the present invention, a resin having a high insulating property, such as an epoxy resin or a silicone resin, having a viscosity sufficient to enter the slit groove in a liquid state,
Anything is fine. It should be noted that the resistor of the present invention can be applied to other than a bleeder resistor and a variable resistor.

[0027]

As described above, according to the high-voltage resistor of the present invention, a slit groove is formed between resistors, electrodes, or between a resistor and an electrode formed on the surface of a ceramic substrate. Formed, and a part of the resin coating layer was inserted into this slit groove.
A three-dimensional withstand voltage structure can be obtained. Therefore, the withstand voltage performance is greatly improved, and discharge breakdown and failure can be prevented. In addition, the withstand voltage performance between the resistors, between the electrodes, or between the electrodes and the resistor is improved, so that the resistors and the electrodes can be arranged at a short distance, and a small high-voltage resistor can be realized. . Furthermore, the anchor effect by the resin entering the slit groove improves the adhesion between the ceramic substrate and the resin coating layer, stabilizes the withstand voltage performance, and improves the reliability.

[Brief description of the drawings]

FIG. 1 is a front view of two examples of a conventional high-voltage resistor.

FIG. 2 is a front view of an example of a high-voltage resistor according to the present invention.

FIG. 3 is a sectional view taken along line XX of FIG. 2;

FIG. 4 is a front view of another example of the high-voltage resistor according to the present invention.

FIG. 5 is a cross-sectional view of an example in which the high-voltage resistor according to the present invention is used as a variable resistor of a focus pack.

FIG. 6 is an enlarged view of a portion A in FIG. 5;

FIG. 7 is a front view of a resistance substrate used in the focus pack shown in FIG. 5;

[Explanation of symbols]

 Reference Signs List 10 ceramic substrate 11 electrode 12 resistor 15 slit groove 17 resin coating layer

Claims (3)

[Claims] 1. A high voltage resistor comprising a ceramic substrate having a resistor and an electrode formed on a surface thereof, and a resin coating layer formed on at least a surface of the ceramic substrate on which the resistor is formed. Wherein a slit groove is formed between the resistors, between the electrodes, or between the resistor and the electrode, and a part of the resin coating layer is inserted into the slit groove. . 2. The high-voltage resistor according to claim 1, wherein said slit groove is formed by laser processing. 3. The method according to claim 1, wherein the depth of the slit groove is not more than 1/10 of the thickness of the ceramic substrate.
Or the high-voltage resistor according to 2.