JPH01185991A - Printed wiring board for high voltage - Google Patents

Abstract

PURPOSE:To obtain at a low cost a printed wiring board for high voltage intended to prevent creepage discharges by forming notches for preventing creepage discharges between conductor patterns for connecting electronic components. CONSTITUTION:On an insulating substrate 1, a plurality of square-shape conductor patterns 3 for connecting electronic components are juxtaposed at an equal space in the longitudinal and traverse directions, and notches for preventing creepage discharges 41-4n are provided between patterns 3 of this insulating substrate 1 in the longitudinal direction. As for electronic components, connecting nine diodes D in series via the pattern 3 forms a group of diodes 21-2n. Notches 41-4n are formed each between this group of diodes 21-2n. Accordingly, the distance between conductor patterns 3 for connecting electronic components on the creepage becomes large, thereby preventing creepage discharges. This does not block for a device to become smaller and lighter, and carbon silicon for easing an electric field becomes unnecessary, resulting in a decline in cost.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention relates to a high-voltage printed wiring board used, for example, in a high-voltage rectifier circuit of an Regarding things that aim to.

(Prior Art) FIG. 3 shows the circuit configuration of an X-ray apparatus, and in the figure, 13 is an input DC power source. The input DC power supply 13 is connected to the primary coil 6 under the transformer via a switch element 14.
is connected. This transformer T is equipped with a secondary coil 10 that is wound in sections, and the secondary coil 6
The input AC power is stepped up and outputted respectively.

A diode 16 is connected in antiparallel between both ends of the switch element 14, and a capacitor 17 is connected in parallel to the negative side coil 6 to form a so-called voltage co-containing single-ended switch circuit. Further, a rectifier circuit 18 is formed in the secondary coil 10 of the transformer T using a plurality of rectifier elements, for example, high-speed diodes, and an X-ray tube as a load is connected between the output terminals of the rectifier circuit 18. It is now possible to do so.

The rectifier circuit 18 has two groups of diodes, each consisting of a predetermined number of diodes connected in series in one conductive direction, connected in parallel in the same polarity direction, with both ends serving as output ends. Then, each coil 9 under the transformer (9A, 9A, 9B, ..., 9n) are connected. The coils 9A, 9B, . . . , 9n are connected in order between the series connection points with their winding directions alternately different. Thereby, the rectifier circuit 18 has a so-called ladder-like connection configuration. In addition, the above coil 9
Differences in the winding directions of A, 9B, . . . , 9n are indicated by marks in the figure. Here, the following explanation will be given assuming that one end of the middle side is the winding start terminal 9a. In addition, as shown in the figure, the diodes constituting the rectifier circuit 18 are
18A1゜18A2 to 18An+x, 18Bt, 1
The numbers 8B2 to 18Bn+1 are given.

In the X-ray apparatus configured as described above, if the switch element 14 is now in a conductive state, each coil 9A, 9B, ..., 9n of the transformer T has a winding start terminal 9a side indicated by A positive voltage is induced in At this time, the voltage of the input DC power supply 13 is maintained as it is. Each coil 9A, 9B,...

The voltages induced on the 9th, respectively, are forward biased diodes 18An+x, 18Bn to 18B4,
18A3, 18B2, and 18At, they are added together and applied to the X-ray tube 19.

Next, when the switch element 14 is turned off, the current energy stored in the leakage inductance and the exciting inductance of the transformer T flows into the capacitor 17. At this time, the power supply voltage Ein applied to the negative side coil 6 falls in an arc of resonance, and eventually becomes a negative potential. Then, after reaching its maximum value (negative potential), it returns to the power supply voltage Ein again. During the period in which the power supply voltage applied from the capacitor 17 becomes a negative potential in this way, the primary coil 6 under the transformer has a reverse polarity.
In other words, a negative potential is applied. As a result, a positive potential is induced in each of the coils 9A, 9B, . These induced voltages are applied to the diodes 18Bn+t, 18An to 18A4.1883 which are forward biased at this time.

18A2.1881 and is added to the X-ray tube 19. This power supply is performed with the same polarity as when the switch element 14 is conducting, and as a result, the voltage induced in the secondary coil 10 is applied to the X-ray tube 19 in the same way as when double-wave rectification is performed. It will be done.

In other words, the switching circuit on the primary coil 6 side of the transformer T is an inverter that uses a voltage resonance waveform.
Each coil 9 of the negative side coil 6 and the secondary side coil 10 hardly uses the excitation inductance of the transformer T.
A, 9B, . . . , 9n and the leakage inductance between them and the resonant voltage waveform with the capacitor 17 are used to obtain a rectified output. Therefore, when the switch element 14 is conductive, the current from the input DC power supply 13 induces a voltage in the coils 9A, 9B, . . . , 9n via the leakage inductance, and
The light is supplied to the X-ray tube 19 via a route n+t.

When the switch element 14 is cut off, the current stored in the leakage inductance is transferred to the coils 9A, 9B, . . .
, 9-n and diodes 18B1゜18A2 to 18B
The capacitor 17 is charged via the X-ray tube ]9.

In other words, in a single-ended switch circuit that mainly resonates due to the leakage inductance and the capacitor 17, the flyback pulse as well as the forward pulse can be used for power transmission, and a double-wave rectified output is possible.

Next, the secondary coil 10 in the transformer T and each of the diodes 18A1 to 18An+1°1881 to 1
The arrangement relationship of 8 B rnt will be explained.

For example, as shown in FIG. 4, the surface of the primary coil 6 is virtually divided into four planes (plane A, plane B, plane 0, plane D), and a fifth plane surrounds these four planes. As shown in the figure, there are two sets of diode connection wiring 2OA.

20B is formed. These two sets of diode connection wiring 2O
A and 20B are bent so as to have diode connection surfaces on two opposing surfaces (surfaces B and D), and descend from top to bottom in a zigzag pattern.
The bending points are arranged adjacent to each other at the boundary between the plane and the 0 plane and at the boundary between the A plane and the D plane. Then, diodes 18A1 to 18A1 are placed on each surface in the upside down direction.
8Arot and 18B1 to 18B net are connected in series, and the two sets of diode connection wiring 2
Coils 9A and 9 are installed adjacent to OA and 20B, respectively.
B, . . . , 9n are connected. That is, the parts that require high voltage resistance are isolated as much as possible.

In addition, in the wiring system shown in Fig. 5, the diodes 18A1 to 18A
Although a case has been described in which one diode is used each as An+1 and the diodes 18B1 to 18Bn+x, a plurality of these can be connected in the same way.

In addition, in the connection method shown in Fig. 5, we have explained the case where diodes are placed on the 8th side and the D side, but the remaining A side and 0th side are
It can also be placed on the surface.

(Problems to be Solved by the Invention) Incidentally, in order to reduce the size and weight of the device, it is conceivable to mount the plurality of diodes described above on a printed wiring board. However, if the plurality of diodes described above are simply mounted on a printed wiring board, there is a problem that creeping discharge is likely to occur because the diodes are used under high voltage. In order to avoid this, it is possible to increase the distance between the diodes or the ground conductor, but this does not allow the device to be made smaller and lighter. In addition, as a high-voltage printed wiring board designed to prevent creeping discharge, the high-voltage side conductor for connecting electronic components arranged on an insulated substrate is surrounded by ground conductors at predetermined intervals, and the space between them is used to create an electric field. There are some products that are characterized by being filled with relaxing carbon silicon (Japanese Patent Application Laid-open No. 6O-77487).
), requires carbon-silicon for electric field relaxation, which poses a problem in terms of manufacturing cost of the printed wiring board.

SUMMARY OF THE INVENTION The present invention aims to eliminate the above-mentioned drawbacks, and its purpose is to provide a high-voltage printed wiring board that prevents creeping discharge at a low cost.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, in the high voltage printed wiring board according to the present invention, cutouts for preventing creeping discharge formed between conductor patterns for connecting electronic components are provided. We are prepared.

(Function) The above creeping discharge prevention notch increases the distance between the electronic component connecting conductors on the creeping surface, thereby preventing creeping discharge. That is, it is sufficient to provide creeping discharge prevention notches at locations where there is a risk of creeping discharge occurring, and this avoids increasing the size of the printed wiring board itself.
This does not impede the reduction in size and weight of the device, and since it does not require carbon-silicon for electric field mitigation, there is no problem in terms of manufacturing cost.

(Example) Hereinafter, the present invention will be specifically explained with reference to Examples.

FIG. 1(a) shows an embodiment of the present invention, and FIG. 1(b)
shows a cross section taken along the line AA' in the same figure (a).

On the insulating substrate 1, a small number of square conductor patterns (hereinafter referred to as "patterns") 3 for connecting electronic components are arranged side by side in the vertical and horizontal directions at equal intervals. Cutouts for preventing creeping discharge (hereinafter abbreviated as "cutouts">41.42°43,...4n) are provided. In FIG. 1(b), the cutouts 41 to 4n are slit-shaped. Although it is a groove, it may also be a slit-like transmission hole.

A plurality of diodes D are used as the electronic component, and by connecting nine diodes D in series in the horizontal direction through the pattern 3, a diode group 21, 22, 23, . . .
. , 2n are formed, respectively. Therefore, the above-mentioned notches 41 to 40 are connected to the diode group 2.
1 to 20, respectively.

According to such a configuration, as shown by 5 in FIG. 1(b), the distance between the patterns 3 on the creeping surface becomes larger than that in the case where the notch 41 is not provided, so that creeping discharge occurs between the patterns 3. is prevented. In this sense, the notches 41 to 4
The depth of n should be as deep as possible, and it is most effective to use a transmission hole. Furthermore, this embodiment does not require carbon-silicon for electric field relaxation, so it is advantageous in terms of cost.

Note that the above-mentioned notch portions may be provided at least at locations where there is a risk of creeping discharge, taking into consideration the voltage between adjacent patterns 3.

The high voltage printed wiring board with the above configuration is
This is used for mounting diodes for single-phase full-wave rectification in X-ray equipment.Next, the case where this high-voltage printed wiring board is applied to an X-ray equipment will be described.

FIG. 2 shows a rectifier circuit using four high-voltage printed wiring boards of the above configuration and arranging a plurality of diodes in a predetermined direction. In addition, in FIG. 1(a), by connecting nine diodes D in series, each diode group 21
The diode groups 21 to 20 are formed because each diode has a low breakdown voltage, and each of the diode groups 21 to 2n can be replaced with one diode having a high breakdown voltage.

In this sense, in FIG. 2, each of the diode groups 21 to 2n is represented by one diode symbol for convenience.

In FIG. 2, corresponding groups of diodes are connected in series by a plurality of cables 7.8. N
1 and N2 are neutral points (GND), and + and - are DC output ends (see Figures 3 and 5).

These high voltage printed wiring boards 1a, lb, 1G.

By making 1d correspond to the A, 8, 0, and D sides of FIG. 4, respectively, and connecting the secondary coil lead wire of the transformer T to these, the X-ray device described above is formed.

It goes without saying that the present invention is not limited to the above-mentioned embodiments, and that various modifications can be made. For example, in the above embodiment, the electronic component is a diode, but the present invention can also be applied to components other than diodes, such as resistors, capacitors, etc., and high-voltage printed circuits used for purposes other than X-ray equipment. The present invention can also be applied to wiring boards.

[Effects of the Invention] As detailed above, according to the present invention, there is provided a high voltage printed wiring board in which creeping discharge is prevented by forming creeping discharge preventing notches between conductor patterns for connecting electronic components. can be provided at low cost.

[Brief explanation of the drawing]

FIG. 1(a) is a plan view showing one embodiment of the present invention, FIG. 1(b) is a sectional view taken along line A-A' in the same figure (a>, and FIG. 2 is an X-ray diagram showing the wiring board of this embodiment. Fig. 3 is a circuit diagram of an X-ray device, Fig. 4 is an explanatory drawing of the surface of the primary coil in Fig. 3 divided into four planes, and Fig. 5 is an explanatory diagram when applied to the device. It is an explanatory diagram of a state in which the secondary coil and the diode are connected in correspondence with Fig. 3. 1... Insulating substrate, 21 to 2n... Diode group, 3... Conductor pattern for connecting electronic components, 41 ~4n・
...Cutout for preventing creeping discharge. Agent Patent Attorney Noriyuki Chika
Takeshi Kondo Figure 1

Claims (1)

[Claims] A high voltage printed wiring board in which a plurality of conductor patterns for connecting electronic components are formed on an insulating substrate, characterized by having a notch for preventing creeping discharge formed between the conductor patterns for connecting electronic components. printed wiring board.