JPH073375B2 - Distributed pressure sensor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a distributed pressure sensor, and more specifically, it is mounted on a robot hand or the like to detect a distribution of force applied in a direction perpendicular to a mounting surface. A distributed pressure sensor that can perform

[Conventional technology]

As a conventional distributed pressure sensor, a sensor using conductive rubber or plastic as a detection element has been proposed. FIG. 3 shows an example thereof, which is constituted by combining conductive rubber strips 8 and 9 which are thinned in the direction perpendicular to each other in two layers. In such a pressure sensor, when a force in the direction perpendicular to the rubber strip arrangement surface is applied, the rubber strip 8
The area of contact with 9 and 9 increases and the resistance decreases. Therefore, as shown in FIG. 4, by applying a voltage of, for example, 5 V to the voltage terminal 10 through the resistance 11 of 1000 Ω, and extracting and measuring the voltage at the output point 12, the magnitude of the applied force can be measured. You can know.

FIG. 5 shows another example of the distributed pressure sensor, which is a Hall element.
13 is provided to face the magnet 14, and when a force in the vertical direction is applied to the pressure receiving surface 16, the Hall element 13 is displaced against the spring 15 to detect the change in the magnetic flux. It is to know the size. FIG. 6 shows still another example,
A semiconductor strain gauge (not shown) is formed on one surface, and the load detecting elements 2 having the pressure receiving portion 2A are arranged in an array on the elastic floor 3 in order to further extract a signal from the load detecting element 2. By connecting the electrodes of the flexible printed circuit board 4 having the wiring of 5 to the load detecting element 2 through the terminal connecting portions 5 such as solder bumps, the object 6
When a vertical load is applied to the pressure receiving portion 2A, the load detecting element 2 is deformed together with the elastic floor 3, and the resistance value of the semiconductor strain gauge is detected to detect the magnitude of the force.

[Problems to be Solved by the Invention]

However, in the distributed pressure sensor of the first example according to the conventional technique, the area of the contact portion does not always change in proportion to the applied force, and the change in the resistance value of the contact portion is not proportional to the force and the sensor output is Since it becomes non-linear and it is necessary to connect the power supply terminal, the ground terminal, and the output terminal to each rubber strip, there are drawbacks such as an increase in the number of wires when trying to detect the force distribution with high density. is there.

Further, in the distributed pressure sensor of the second example according to the conventional technique, the mechanism for displacing the Hall element 13 in accordance with the applied force becomes complicated, so that the distribution density of the sensor cannot be increased, and further, As in the first example, there is a drawback that the number of wires increases.

Furthermore, in the distributed pressure sensor of the third example according to the prior art, the sensor output nonlinearity in the above first and second examples,
Although the complicated mechanism and the problems such as the large number of wirings have been solved, when the object 6 comes into contact with the load detecting element 2 at a point outside the pressure receiving portion 2A as shown in FIG. The object 6 comes into contact with the board 4, the flexible printed circuit board 4 is deformed as shown in FIG. 8, and stress is applied to the terminal connection portion 5 between the load detection element 2 and the circuit board 4.

Further, in the ordinary flexible printed circuit board 4, the terminal connecting portion 5 is formed in a layer on the upper surface thereof as shown in FIG. 9, and the rigidity of the terminal connecting portion 5 is relatively high.
When a load is directly applied to the pressure receiving portion 2A as shown in FIG. 10, the load detecting element 2 is deformed as shown in FIG.
The terminal connection portion 5 connecting the load detection element 2 and the flexible printed circuit board 4 is intensively stressed, which causes a decrease in reliability of electrical connection to the terminal connection portion 5. Further, since there is no standard for positioning the load detecting element 2 and the elastic floor 3, a jig for positioning is required when manufacturing a large number of sensors, which leads to an increase in cost. Was also a problem.

An object of the present invention is to solve the above-mentioned problems,
It is an object of the present invention to provide a distributed pressure sensor that can disperse the stress applied to the terminal connection portion as much as possible with respect to the load applied to the load detection element.

[Means for Solving the Problems]

In order to achieve such an object, the present invention, on an elastic floor,
A flexible print with a semiconductor strain gauge for load detection and a plurality of load detection elements each having a terminal connection portion for signal extraction from the semiconductor strain gauge arranged in a matrix and having a circuit connected to the terminal connection portion The circuit board is provided on a plurality of load detecting elements with a predetermined interval, and the pressure receiving portion of the load detecting element is projected upward from the flexible printed circuit board, and the load applied to the load detecting element via the pressure receiving portion. In a distributed pressure sensor capable of detecting a load, a spacer member capable of supporting a flexible printed circuit board is provided between load detection elements on an elastic floor, and the flexible printed circuit board is easily bent up and down for each terminal connection portion. It is characterized in that it is formed.

[Action]

According to the present invention, a spacer member for supporting a flexible printed circuit board disposed between load detection elements on an elastic floor,
That is, the flexible printed circuit board is supported by the support member, and excessive deformation thereof can be suppressed, and the portions of the flexible printed circuit board related to the terminal connection portions are formed in a shape that is easily bent up and down. By this, even if the load detection element is deformed by the load, the individual terminal connecting parts themselves are flexibly displaced together with the circuit board, so that the connecting parts can be prevented from being pulled off, and the pressure sensing The reliability as a sensor can be improved.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail and specifically with reference to the drawings.

1 and 2 show an embodiment of the present invention. In these figures, 10 is a spacer member disposed between the load detecting elements 2 on the elastic floor 3, and its height is set to
As shown in the figure, it is formed so as to be substantially aligned with the upper surface of the terminal connecting portion 5. It should be noted that such a spacer member 10 may be formed integrally with the elastic floor 3 by using the same material.

Further, here, the flexible printed circuit board 4 is
As shown in the figure, the board itself is divided along the printed circuit in the vicinity of the periphery of the load detecting element 2 so that the terminal connecting portions 5 connected to the load detecting element 2 are independent of each other. With this configuration, even if the load detection element 2 itself or the flexible printed circuit board 4 is deformed due to the load, the spacer member 10 is flexible printed in the middle of the pressure receiving portion 2A. In addition to suppressing the deformation of the circuit board 4, the flexible printed circuit board 4 itself flexes and flexes in the vicinity of the terminal connection portion 5 so that stress concentration does not occur, so that the connection state of the terminal connection portion 5 is impaired. There is no.

〔The invention's effect〕

As described above, according to the present invention, for the load detecting elements arranged in a matrix on the elastic floor, the spacer member capable of supporting the flexible printed circuit board is provided between the load detecting elements on the elastic floor. Since this flexible printed circuit board is formed in such a shape that it can be easily bent up and down for each terminal connection portion with the load detection element, even if the load detection element itself or the flexible printed circuit board is deformed by the load, multiple terminal connections can be made. It is possible to relieve the concentrated stress applied to the portion, and further, by providing the spacer member, the positioning when arranging the load detection elements on the elastic floor becomes easy.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of an embodiment of the present invention, FIG. 2 is a sectional view taken along the line BB ′ of FIG. 1, FIG. 3 is a structural view of the first example according to the prior art, and FIG. Is an explanatory view of the operation of the example shown in FIG. 3, FIG. 5 is a side view of the second example according to the prior art, FIG. 6 is a sectional view showing the configuration of the third example according to the prior art, and FIG. FIG. 8 is an explanatory view of a load detecting operation by partially enlarging the drawing, FIG. 8 is an explanatory view of an operation deformed by the operation of FIG. 7, FIG. 9 is a sectional view taken along the line AA ′ of FIG. 8, and FIG. FIG. 6 is an explanatory view of another operation by partially enlarging FIG. 6, and FIG. 11 is an explanatory view of a deforming operation generated by the operation of FIG. 2 ... Load detection element, 2A ... Pressure receiving part, 3 ... Elastic floor, 4
...... Flexible printed circuit board, 5 ...... Terminal connection part, 10 ...... Spacer member.

Claims (1)

[Claims] 1. A plurality of load detecting elements, each having a semiconductor strain gauge for detecting a load and a terminal connecting portion for extracting a signal from the semiconductor strain gauge, are arranged in a matrix on an elastic floor, and the terminal connecting portion is arranged. A flexible printed circuit board having a circuit connected to is provided at a predetermined interval on the plurality of load detecting elements, the pressure receiving portion of the load detecting element is projected upward from the flexible printed circuit board, A distributed pressure sensor capable of detecting a load applied to the load detection element via the pressure receiving section, wherein a spacer member capable of supporting the flexible printed circuit board is provided between the load detection elements on the elastic floor. , The flexible printed circuit board is formed in a form that is easily bent up and down for each of the terminal connection parts. Characteristic distributed pressure sensor.