JPS60154678A - Sense of pressure sensor - Google Patents

Abstract

PURPOSE:To reduce wirings by integrating analog switches with a pressure sensitive structure of unit cells and connecting input/output wirings. CONSTITUTION:Analog switches 31, 32 connected with an output terminal Z and an analog switch 33 connected with an input terminal V are formed on a region having small strain at the intermediate on the surface 12 of a pressure sensitive structure in addition to a strain gauge region 21. The analog switches are formed as MOS transistors. In other words, a P type diffused layer 43 is formed in an N type epitaxial layer 42 formed on a P type silicon substrate 41, and N<+> type source, drain layer 44 is formed therein. The surface of the silicon plate is coated with an oxide film 45, a gate electrode 46 is formed thereon, and an N- channel MOS transistor 3 is formed. On the other hand, a strain gauge region is formed of a P type diffused region 47, and connected via thin metal wirings 5. The connection to the substrate 41 utilized as ground wirings is performed by a P type diffused layer 48.

Description

[Detailed description of the invention] [Technical field to which the invention pertains] The present invention is a pressure-sensitive device made of a semi-transparent crystal, in which an initial strain gauge region of opposite conductivity type is formed on a surface layer of 14-conductivity type. A plurality of strain gauges are arranged in an array on top, and when a force is applied to each pressure-sensitive structure, the output voltage generated in the bridge made of strain gauges determines the magnitude of the three components of the force applied to the pressure-sensitive structure. The present invention relates to a pressure sensor that detects the surface distribution of pressure.

[Prior art and its problems]

In a robot hand that handles various objects, in order to handle the object with the appropriate gripping force depending on the type of object, the gripping force, that is, the magnitude and distribution of the load applied to the fingers of the robot hand, must be precisely detected and gripped. Power must be controlled. For such a purpose, a small pressure sensor unit cell as shown in Fig. 1 has been proposed, and to detect a planar distribution, an array of pressure sensor modules consisting of a single I cell or two unit cells is used. The pressure sensors are arranged in the shape of I! (To be accomplished.)

This unit cell has 12 P-type strong regions 21, 22 formed by diffusion from the surface 1 of the ring-shaped pressure-sensitive structure 1, which is perpendicular to the pressure-receiving surface 11, made of, for example, N-type silicon single crystal.
．． 23 and is fixed to a support by the bottom surface 13 facing the pressure receiving surface 1.

The output of the bridge composed of the strain gauge 21 ↑L is applied to the pressure receiving surface 11 due to the unidirectional component Fz, and the output frost of the bridge composed of the strain gauge 22 is One component Fx in the direction parallel to the pressure receiving surface J1,
The remaining one component Fy is detected based on the output voltage of the bridge constituted by the strain gauge 23. The output signal of such a bridge is input to the amplification section, but the output signal from each unit cell or pressure-sensitive module (in order to reduce the wiring for taking out the Q and supplying human power to them) It is desirable to be able to scan input supply and output output for each unit cell or module.

[Purpose of the invention]

An object of the present invention is to provide a pressure sensor that facilitates such scanning and reduces wiring.

[Disadvantages of the invention]

According to the present invention, the above object is achieved by integrating an analog switch in the pressure sensitive structure of a unit cell of a pressure sensor and connecting it to the input/output wiring. It is advantageous to form the analog switch as a MOS transistor.

[Embodiments of the invention]

2 and 3 show an embodiment of the present invention. In this case, a silicon plate is used as a single crystal semiconductor and has epitaxial layers of different conductivity types on both sides of the substrate, and Fz detection is applied to the epitaxial layer on one side. A bridge for detecting Fx and Fy is formed in the epitaxial layer on the other side. Surface 12 of the pressure sensitive structure shown in FIG.
In addition to the strain gauge area 21, there is an analog switch 3 connected to the output terminal Z in a small area in the middle thereof.
1゜32, analog switch 3 connected to input terminal V
3 is formed. This analog switch is formed as a MOS transistor, as shown in FIG. That is, a P-type wave dispersion layer 43 is formed in an N-type epitaxial layer 42 provided on a P-type silicon substrate 41,
Further, an N+ type source/drain layer 44 is formed therein. The surface of the silicon plate is covered with an oxide film 45, on which a gate t and a pole 46 are provided, and an N-channel MO8
) A transistor 3 is configured. On the other hand, the strain gauge f
It is formed by the Jl region UP type diffusion N47, and the connection with the groove is p-connected by the metal thin film interconnection IM5. Connection to the substrate 4 used as ground wiring is made by a P-type wave dispersion layer 48. This grounding portion is represented by a small circle 6 in FIGS. 2 and 3. FIG. 3 shows the back side 14, with output terminals X,
Analog switches 34 to 37 connected to Y and an analog switch 38 connected to input terminal V are formed in the left and right intermediate portions where distortion is small, similar to the front surface.

MOS shown in Figure 4) The transistor 3 is 14 poles 46
When a positive voltage is applied to the gate electrode 4, the gate electrode 4 becomes electrically conductive.
When the pressure applied to the box 6 is zero or negative, conduction occurs.

FIG. 6 shows an embodiment in which, in addition to analog switches 31 to 33 and 39, a temperature sensor 7 and a thin film resistor 8 connected in series thereto are formed on the FZ detection bridge forming surface with a low wiring density. FIG. 7 shows an example of the circuit configuration of a pressure sensor using a unit cell based on the present invention, and the symbols written in the figure correspond to the parts written in the figures showing the embodiments of the present invention. do. Input wiring 51, 52, output wiring 53
, 54 and 55 are sequentially turned on and off by a signal from the control unit 10 to perform scanning and output signals from each bridge for detecting Fx, Fy, and Fz of each unit cell. are sequentially taken out to the amplifying section 20.

〔Effect of the invention〕

In the present invention, an analog switch is provided on the pressure-sensitive 'fPi, +S body of a pressure-sensitive sensor unit cell, and it is possible to supply input to the unit cell or pressure-sensitive module and output (retrieval of the U number) by scanning υ Since the number of wires between the strain gauge section and the signal processing section of a unit cell is greatly reduced, it is extremely easy to construct an array pressure sensor incorporating a large number of cells.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a pressure sensitive structure of a pressure sensor unit cell, FIG. 2 is a plan view of the surface of the pressure sensitive structure according to an embodiment of the present invention, FIG. 3 is a plan view of the back side, and FIG. 4 is a sectional view of a thick part of a pressure-sensitive structure showing an embodiment of an analog switch according to the present invention;
FIG. 5 is a front view of the various parts of the pressure-sensitive structure showing another embodiment of the analog switch, FIG. 6 is a top view of the surface of the pressure-sensitive structure of a different embodiment of the present invention, and FIG. FIG. 2 is a circuit diagram of a pressure sensor according to an embodiment of the present invention. J...6 pressure-sensitive bodies, 2.1.22.23...
. . . strain gauge region, 3. 31.32. 33
．． 34. 35.36.37゜38.39...
Analog switch, 5... Wiring. z 1st figure f2 figure so-called '3 ward fang 4 figure sai j flash 7.7 no! size 2

Claims (1)

[Claims] ■) A plurality of pressure-sensitive structures made of semiconductor J\crystal and having a plurality of strain gauge regions of opposite conductivity type formed on a surface layer of one conductivity type are arranged in an array, and a force is applied to each pressure-sensitive structure. In a device that detects the surface distribution of the magnitude of the three components of the force applied due to the output image produced on the bridge consisting of a strain gauge and pressure, #I■, an analog switch is installed in the structure, A pressure sensor that features a "grooved" contact during input/output wiring.