JPH0355918Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a sensor device, and more particularly, to a sensor device that generates and outputs a signal corresponding to the amount of change in a physical object to be measured.

Prior Art FIG. 2 shows a perspective view of an example of a conventional sensor device. In the figure, a sensor 1 that generates and outputs a signal corresponding to the amount of change in a physical measurement target such as pressure or acceleration is connected to an electronic circuit 3 in which electronic components 2, etc. are installed on a circuit board via a connecting line 4. connected.
The output signal of the sensor 1 is supplied to the electronic circuit 3 via the connection line 4, where it is subjected to signal processing such as amplification and impedance conversion, and then output to the outside. In addition, noise due to electrostatic induction from the outside occurs in the output signal of the electronic circuit 3,
In order to prevent the S/N from deteriorating, the sensor 1, electronic circuit 3, etc. are housed in an electrostatic shield case 5.

Problems to be Solved by the Invention However, in the conventional sensor device described above, without the electrostatic shielding case 5, the sensor 1 and the electronic circuit 3 are physically separated, and the connecting wire 4 connecting them is
There was a problem in that noise was generated due to electrostatic induction, and the S/N ratio of the output signal of the electronic circuit 3 deteriorated. In order to solve this problem, methods such as connecting the sensor 1 and the electronic circuit 3 with a shielded wire, or housing both in the electrostatic shielding case 5 as described above can be considered. If this configuration is adopted, the weight of the sensor device itself increases, and the cost also increases.

In addition, as another solution to the above problem, the third
As shown in the figure, it is also possible to integrate the sensor 6 and the electronic circuit 7 and omit the connection wire 4;
In this case, although deterioration of S/N due to electrostatic induction to the connection line 4 can be prevented, electrostatic induction to the sensor 6 itself still remains, resulting in problems such as insufficient S/N of the output signal. The dot was hot.

Therefore, an object of the present invention is to provide a sensor device that solves the above problems by using the electronic circuit for processing the output signal of the sensor as an electrostatic shielding material.

Means for Solving the Problems The sensor device according to the present invention includes a sensor, performs predetermined signal processing on the output signal of the sensor, has an output impedance lower than the output impedance of the sensor, and has an output impedance that is lower than the output impedance of the sensor. It consists of an electronic circuit fixed to one side via a conductive adhesive.

Function Since the above electronic circuit has a low output impedance, it is less susceptible to the effects of electrostatic induction, and can also be used as an electrostatic shielding material. Therefore, by fixing the electronic circuit to at least one surface of the sensor via a conductive adhesive, deterioration of the S/N of the output signal of the sensor due to electrostatic induction can be prevented.

Embodiment FIGS. 1A and 1B show a perspective view and a front view, respectively, of a first embodiment of a sensor device according to the present invention. In Figure A, 8 is a so-called ceramic acceleration sensor (hereinafter referred to as "sensor") that utilizes the piezoelectric effect of ceramic, and this generates and outputs signals corresponding to applied acceleration, pressure, vibration, etc. For,
For example, it is attached to the tip of the voice coil of a speaker and used for purposes such as detecting its vibrations. Further, 9 is an electronic circuit in which electronic components 10 and the like are installed on a circuit board, and similarly to the electronic circuit 3, it processes the output signal of the sensor 8 and outputs it to the outside via an external connection line. do.

The ceramic acceleration sensor 8 generally has a high output impedance and is susceptible to electrostatic induction. Further, the output point of the sensor 8 and the connection part to the amplifier in the electronic circuit 9 are most susceptible to the effects of electrostatic induction. Therefore, in the present invention, as the electronic circuit 9, a circuit with low output impedance such as a grounding circuit or a power supply circuit, in other words, a circuit having an electronic component or a circuit pattern that is not easily affected by electrostatic induction is selected. There is.

As shown in FIG. 1B, the electronic circuit 9 is constructed by applying a conductive adhesive 1 to one surface of the flat donut-shaped sensor 8.
1. As a result, one surface of the sensor 8 is substantially shielded, and noise generation and S/N deterioration of the output signal due to the influence of electrostatic induction from the direction shown by the arrow X are prevented.

Effects of the Invention As described above, according to the present invention, by using the signal processing electronic circuit of the sensor device as an electrostatic shielding material, static electricity is prevented not only from the connection line connecting the sensor and the electronic circuit but also from the sensor itself. It has features such as being able to prevent the occurrence of induction, obtaining a good S/N ratio of the output signal, and further reducing the weight and cost of the sensor device.

[Brief explanation of the drawing]

Figures 1A and B show the first sensor device of the present invention.
The figures showing the embodiment, FIGS. 2 and 3, each show an example of a conventional sensor device. 8...Ceramic acceleration sensor, 9...Electronic circuit, 10...Electronic component, 11...Adhesive.

Claims (1)

[Scope of utility model registration request] It consists of a sensor and an electronic circuit that performs predetermined signal processing on the output signal of the sensor and has an output impedance lower than the output impedance of the sensor, and the electronic circuit has a conductive surface on at least one surface of the sensor. A sensor device that is fixed using adhesive.