JPS58202876A - Potential sensor - Google Patents

Abstract

PURPOSE:To stabilize the performance by employing a ceramic substrate for the substrate carrying a sensor section and the like to make an amplification circuit hybrid. CONSTITUTION:A substrate 13 made of ceramics is provided thereon with a turning fork 2 to convert into alternate current the electric line of force 7 entering from a detection hole 1a of a case 1 and an electrode 3 to extract an AC signal from the electric line of force converted into alternate current. A piezo- electric ceramics 6 for driving is bonded on the turning fork 2. An output amplification circuit comprising a transistor 11 and a print resistance 12 is formed on the substrate 13 to be made hybrid and covered with a glass film. Thus, even in the case of a high humidity, a stable output voltage can be obtained without lowering the input impedance to stabilize the performance.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a potential sensor used for detecting the strength of an electrostatic field, measuring the amount of charge, and the like.

Generally, a potential sensor has a case with a detection hole for introducing the lines of electric force radiated from the object to be measured, and a small case that cuts the lines of electric force entering the case at a certain period and converts them into alternating current. Figure 1 shows the conventional potential of such a configuration. It is a figure showing an example of a sensor. Onsa 2 with driving piezoelectric ceramics 6 bonded is used for the bottom part of the chiyosono.
The stain air force line 7 is cut by the tip.

The detection electrode 3 is fixed to a printed circuit board 8 and placed behind the tip of the oncer. Further, on the printed circuit board, a resistor 10 and a transistor 1 are provided adjacent to the detection electrode 3.
1 is formed. These substrates, sensors, and amplifier circuits are housed in a case 1 having a detection hole.

Since the potential sensor with the above configuration has a detection hole in the case, it is exposed to the same conditions as the external atmosphere and is easily influenced by the external environment.

In particular, the input section of the amplifier circuit connected to the detection electrode has a high input impedance and is therefore easily affected by humidity, resulting in a problem in that the output voltage fluctuates as the humidity increases.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks, and to provide a potential sensor that is not dependent on the external environment and is capable of obtaining a stable output voltage.

In order to achieve the above object, the potential sensor according to the present invention includes a chopper section that cuts the lines of electric force radiated from the object to be measured at regular intervals and converts them into alternating current, and a chopper section that cuts the lines of electric force radiated from the object to be measured and converts them into alternating current. A potential is obtained by housing a board equipped with a sensor section comprising an electrode for extracting AC output and an amplifier circuit for amplifying the AC output in a case having a detection hole for introducing the electric lines of force. In the sensor,
A ceramic substrate is used as the substrate, and the amplifier circuit is formed into a mixed integrated circuit.

According to the above configuration, since the amplifier circuit section is covered with a glass film, the influence of humidity is small and stable output can be obtained.

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

FIG. 1(a) is a partial sectional view showing an embodiment of the potential sensor according to the present invention; FIG. 1(a) is a plan view, and FIG.
b) is a front view.

The material of the substrate 13 is ceramic. On this ceramic substrate 13, there is a sensor 2 for converting the electric lines of force 7 entering from the detection hole 1a of the case 1 into alternating current, and an electrode 3 for receiving the electric lines of force 7 converted to alternating current and extracting an alternating current signal. is installed.

A piezoelectric ceramic 6 for driving is bonded to the oncer 2. Further, an output amplification circuit consisting of a transistor 11 and a printed resistor 12 is formed on the ceramic substrate 13, and this circuit is a hybrid (HIC) circuit.
has been made into

Hybrid circuits are generally covered with a glass coating, so
It is less affected by humidity, so even if the humidity increases, the input impedance does not drop and a stable output voltage can be obtained.

In the present invention, it is also possible to pattern the electrodes 3 on a ceramic substrate.

As explained above in detail, according to the present invention, a potential sensor with stable performance can be obtained by converting the amplification circuit inside the t-position sensor into an HTC.

The No. 1 senna according to the present invention has fewer components due to HTC, making it easier to manufacture than before.

It is also suitable for miniaturization and has great industrial value.

[Brief explanation of drawings]

, π1 Figures (a) and (b) are a top sectional view and a front sectional view, respectively, showing a conventional potential sensor, and Figures 2 (a) and (b) are top sectional views showing an embodiment of the potential sensor according to the present invention. and a front sectional view. 1...Case 2...On sensor 3...Detection electrode 4...Drive terminal 5...Output terminal
6... Piezoelectric ceramics 7... Electric lines of force
8... Printed circuit board 9... Earth terminal 10.
...Resistor 11...Transistor 12...Printed resistor 13...Ceramic substrate patent, applicant: NEC Corporation

Claims (1)

[Claims] A chopper section that cuts the electric lines of force radiated from the object to be measured at regular intervals and converts them into alternating current, an electrode that receives the electric lines of force converted to alternating current and extracts alternating current output, and amplifies the alternating current output. A potential sensor comprising: a substrate mounted with a sensor section comprising an amplifier circuit and an amplifier circuit; housed in a case having a detection hole for introducing the electric lines of force;
A potential sensor characterized in that a ceramic substrate is used as the substrate, and the amplifier circuit is formed into a hybrid integrated circuit.