JP2000088901A - Surface and volume electrical resistance measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface and volume electrical resistance measurement device with a structure that enables easily replacing a part. SOLUTION: A disc-like main electrode 11 and a ring electrode 12 placed so as to encircle a surrounding of the main electrode 11 are provided on an insulation circular platform equipped at a bottom face of a case 22. A sample 13 is mounted on the electrodes 11, 12 and an opposed electrode 14 is placed on the sample 13. A surface electrical resistance of the sample 13 is measured by applying a d-c voltage between the main electrode 11 and the ring electrode 12. In a surface and volume electrical resistance measurement device measuring a volume electrical resistance of the sample 13 by applying a d-c voltage between the main electrode 11 and the opposed electrode 14, a position determining means 30 is projected from the bottom face of the case 22 and the opposed electrode 14 is made so as to have a structure that supports attachably and detachably with the position determining means 30 and a conductive rubber 18 covering the opposed electrode 14 is easily replaced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface resistance measuring device for measuring the surface resistance of various insulating materials and a volume resistance measuring device for measuring a current flowing through the insulating material to measure a volume resistance.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Industrial Standard JIS K6911
Defines a surface resistance measuring method for measuring the surface resistance of an insulating material and the like, and a volume resistance measuring method for measuring a current flowing through the insulating material. FIG. 5 shows a method of measuring surface resistance. In the figure, 11 is a disk-shaped main electrode, 12 is this main electrode 1
The ring electrode 13 surrounding the sample 1 is the sample 1
4 is a counter electrode, 15 is a DC voltage source, and 16 is a current measuring means.

The main electrode 11 has a disk shape, and a ring electrode 12 is arranged around the main electrode 11. The main electrode 11 and the ring electrode 12 are supported on an insulating table 17 such that the upper surfaces thereof are flush with each other. As shown in FIG. 7, the insulating base 17 is mounted on the bottom surface of the case 22 and supports the upper surfaces of the main electrode 11 and the ring electrode 12 in the case 22 in the same plane. At the same time, the opposing electrode 14 is mounted on an opening / closing lid 23 supported so as to be openable and closable.
4 is arranged at a position facing the main electrode 11 and the ring electrode 12.

Therefore, when the lid 23 is closed with the sample 13 placed on the main electrode 11 and the ring electrode 12, the counter electrode 14 is closed.
Presses the sample 13 on the main electrode 11 and the ring electrode 12,
Maintain the pressure contact state. In this state, a DC voltage (500 to 500) is applied between the ring electrode 12 and the main electrode 11 from the DC voltage source 15.
(About 1000 V), and a DC voltage is applied between the ring electrode 12 and the counter electrode 14. Although not shown, a door switch is provided on the open / close lid 23 so that a DC voltage can be applied only when the open / close lid 23 is closed.

[0005] By applying this voltage, the current I _S flows through the surface of the sample 13 as shown in FIG. 5 between the main electrode 11 and ring electrode 12, measures the current I _S in current measuring means 16 Accordingly, the surface resistance value R _{SUF is calculated} by the current value J (μA) and the voltage _VDC of the DC voltage source 15.
It can be determined by V _DC / J (μA). In this case, the leakage current _IV flowing out of the ring electrode 12 is attracted to the counter electrode 14 in this case, and the leakage current _IV is supplied to the current measuring means 16.
It has a circuit structure that prevents it from flowing into.

On the other hand, in the measurement of the volume resistance, as shown in FIG. 6, a DC voltage is applied between the counter electrode 14 and the main electrode 11 by a DC voltage source 15, and a current flowing from the counter electrode 14 to the main electrode 11 through the sample 13. I _S is measured by the current measuring means 16, and the measured value is divided by the area of the main electrode 11, and the current value K (μ) flowing through the unit area of the sample 13 is measured.
Find A). This current value K (μA) and the DC voltage source 15
The volume resistance can be determined from the voltage value _VDC .

In this case as well, the leakage current _IV flowing out of the counter electrode 14 is absorbed by the ring electrode 12, and the leakage current I
It has a circuit structure for preventing _V from flowing into the current measuring means 16. By the way, it is specified that the surfaces of the electrodes 11, 12 and 14 that come into contact with the sample 13 are covered with the conductive rubber 18. The reason is that the shape of the electrode is adapted to the surface of the sample 13 to stabilize the contact.

Since the conductive rubber 18 is generally formed by mixing carbon or the like into rubber, it can be regarded as a conductor having a relatively large resistance value. For this reason, the sample 13 is temporarily replaced with the main electrode 11.
If the lid 23 shown in FIG. 7 is closed in a voltage applied state before being put on the counter electrode, the direct contact is made between the counter electrode 14 and the main electrode 11 or between the counter electrode 14 and the ring electrode 12,
A large current flows through the conductive rubber 18 and the conductive rubber 18
However, there is an inconvenience that an accident may occur in which the burn-in resistance changes to a high state.

In the case where the electrodes are in direct contact with each other, for example, when the surface resistance and the volume resistance of a thin sample are measured in addition to the above-mentioned situation, the sample comes into contact during measurement, for example, due to breakage. An accident is possible.

[0010]

For these reasons, the conductive rubber 18 is considered as a kind of consumable which must be replaced frequently. Since the main electrode 11 and the ring electrode 12 are in the posture fixed upward on the case 22 side, the operation of exchanging the conductive rubber 18 attached to them can be performed relatively easily.

However, since the counter electrode 14 is mounted on the back surface of the lid 23, the work of replacing the conductive rubber 18 attached to the counter electrode 14 is not easy and troublesome. An object of the present invention is to provide a surface / volume resistance measuring device having a structure that allows easy replacement of a conductive rubber covering the counter electrode 14.

[0012]

An insulating table is provided in a case having an opening / closing lid, and a disk-shaped main electrode and a ring electrode arranged around the main electrode are mounted on the insulating table. Then, a sample is placed over the main electrode and the ring electrode, a counter electrode is arranged on the sample, and a DC voltage is applied between the main electrode and the ring electrode or between the main electrode and the counter electrode. In a surface / volume resistance measuring device that measures the surface resistance or volume resistance of a sample by measuring the current flowing between the main electrode and the ring electrode or the current flowing between the main electrode and the counter electrode, Positioning means for determining the position, and a power supply means for applying a DC voltage to the counter electrode positioned by the positioning means are provided, and the counter electrode is detachably attached to the case. It proposes a product resistance measuring device.

According to the structure of the present invention, since the counter electrode is detachably attached to the case, it can be removed from the case as required. Since the counter electrode can be handled outside the case, there is an advantage that the conductive rubber can be replaced very easily.

[0014]

FIG. 1 shows an embodiment of a surface / volume resistance measuring apparatus according to the present invention. In the present invention, case 2
A conductive pin 31 protrudes upward in a state of being insulated from the bottom surface side of the second electrode 2, and a through-hole 32 is formed on the counter electrode 14 side to penetrate the conductive pin 31. The conductive pins 3 constituting the positioning means 30 of the electrode 14 and the positioning means 30
1 shows a configuration in which a power supply unit that applies a DC voltage to the counter electrode 14 through the common electrode 1 is also used. Note that the example shown in FIG. 1 shows a case where a conductive pin, which is generally called a banana chip or the like and shrinks and deforms in the diameter direction, is used as the conductive pin 31.

FIG. 2 shows a detailed structure of the counter electrode 14. In this example, the counter electrode 14 is configured by mounting a disk 14B similarly formed of a metal plate on a rectangular flat plate (metal plate) 14A. Pressing plate 2 on the side where disk 14B is mounted
4 is attached. A hole 24A having a diameter larger than the diameter of the disk 14B is formed in the pressing plate 24, and the disk 14B and the conductive rubber 18 covering the disk 14B are formed through the holes 24A as shown in FIG. Protrude to the other surface.

The holding plate 24 is extended outward from one side of the flat plate 14A constituting the counter electrode 14, and this extended portion 24B
Then, a through hole 32 constituting the positioning means 30 described above is formed. In this example, two through holes 32 are formed, and the two through holes 32 are connected to two conductive pins 31 protruding from the bottom side of the case 22 to fix the position of the counter electrode 14. Press plate 24 is screw 2
5 (see FIG. 1), and the conductive rubber 18 is sandwiched therebetween to integrate the conductive rubber 18 and the counter electrode 14. The cable 26 is connected to the conductive pin 31.
Is connected, a DC voltage is applied to the conductive pin 31 through the cable 26, and the DC voltage is applied to the counter electrode 14 through the suppressing plate 24 and the screw 25. Open / close lid 23
A door switch is provided in conjunction with the opening and closing of the switch. A switch circuit is configured such that a DC voltage is applied by the door switch with the opening and closing lid 23 completely closed.
In the example shown in FIG. 1, a holding spring 27 supported by, for example, an insulating material is mounted on the back side of the opening / closing lid 23, and when the opening / closing lid 23 is closed, the holding spring 27 holds down the opposing electrode. This shows a case in which a large pressing force is applied.

FIG. 3 shows a modified embodiment of the present invention. In this example, a case where a pogo pin is used as the conductive pin 31 for positioning is shown. The pogo pin includes a contact 31B which is elastically protruded outward by a spring inserted into the conductive pin 31A at the tip of the conductive pin 31A, and since the contact 31B is elastically biased, A conductive pin having a function of reliably maintaining electrical continuity even when a partner to be contacted is slightly displaced in the near and far directions.

When the conductive pin 31 is used, a cylindrical body 33 is mounted on the holding plate 24, and the conductive pin 31A is inserted into the engaging hole 33A of the cylindrical body 33 to fix the position of the counter electrode 14. At the same time, the contact 31 </ b> B can be configured to resiliently contact the holding plate 24 to make electrical contact therewith and supply a DC voltage to the counter electrode 14. FIG. 4 shows still another embodiment of the present invention. In this embodiment, a positioning means 30 made of an insulating material is protruded from the bottom side of the case 22, and the position of the counter electrode 14 is positioned by the positioning means 30, and the positioned position is maintained. Shows a case in which the power supply means is mounted on the power supply. It is conceivable to divert the pressing spring 27 as the power supply means. The holding spring 27 is attached to the back side of the opening / closing lid 23 via the insulating material 28,
The opposing electrode 14 is configured to be held down at the free end of the holding spring 27, and the cable 26 is connected to the holding spring 27 so that a DC voltage is applied to the opposite electrode 14 in the contact state.

[0019]

As described above, according to the present invention, the opposing electrode 14 is detachably supported on the case 22. Therefore, when the conductive rubber 18 is replaced, the opposing electrode 14 is moved outside the case 22. Can be removed and replaced. Therefore, the replacement work of the conductive rubber 18 is simplified and can be replaced by anyone. In this respect, there is obtained an advantage that an easy-to-use surface / volume resistance measuring device can be provided, and the effect is extremely large for practical use.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention.

FIG. 2 is a perspective view for explaining the structure of a counter electrode and a holding plate shown in FIG.

FIG. 3 is a sectional view for explaining a modified embodiment of the present invention.

FIG. 4 is a sectional view for explaining still another embodiment of the present invention.

FIG. 5 is a sectional view for explaining a surface resistance measuring method.

FIG. 6 is a cross-sectional view for explaining a volume resistance measuring method.

FIG. 7 is a sectional view for explaining the structure of a conventional surface / volume resistance measuring device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Main electrode 12 Ring electrode 13 Sample 14 Counter electrode 15 DC voltage source 16 Current measuring means 17 Insulating table 18 Conductive rubber 22 Case 23 Cover 24 Suppression plate 25 Screw 26 Cable 27 Suppression spring (power supply means) 30 Positioning means 31 Conductive pin 32 Through hole 33A Engagement hole

Claims (4)

[Claims] An insulating base is provided in a case provided with an opening / closing lid, and a disk-shaped main electrode and a ring electrode disposed around the main electrode are mounted on the insulating base. A sample is placed over the sample and the ring electrode, a counter electrode is arranged on the sample, and a DC voltage is applied between the main electrode and the ring electrode or between the main electrode and the counter electrode to apply the DC voltage to the main electrode and the ring electrode. In the surface / volume resistance measuring device for measuring the surface resistance and the volume resistance of the sample by measuring the current flowing between the main electrode and the counter electrode and the current flowing between the main electrode and the counter electrode, A surface having a structure in which a positioning means for determining and a feeding means for applying a DC voltage to the counter electrode positioned by the positioning means are provided, and the counter electrode is detachably attached to the case. The volume resistivity measurement apparatus. 2. The surface / volume resistance measuring device according to claim 1, wherein a conductive pin is provided which is insulated from the bottom side of the case and protrudes upward, and the counter electrode has a through hole which engages with the conductive pin. A surface / volume resistance measuring apparatus, wherein the positioning means and the power supply means are formed by using the conductive pins and the through holes. 3. The surface / volume resistance measuring device according to claim 1, further comprising: a conductive pin that is insulated from a bottom surface of the case and protrudes upward, and the counter electrode has an engagement hole that engages with the conductive pin. A surface / volume resistance measuring device, wherein the positioning means and the power feeding means are constituted by the conductive pins and the engagement holes. 4. The surface / volume resistance measuring device according to claim 1, wherein said counter electrode is positioned and held by positioning means provided in said case, and said opening / closing lid is provided with an elastic member on an upper surface of said counter electrode. A surface / volume resistance measuring device, characterized in that a contact spring is provided, and the electricity supply means is constituted by the contact spring.