CN107063514A - The pressure sensor and its method of work of a kind of utilization electrostatic principle - Google Patents

Abstract

The invention discloses a pressure sensor utilizing the principle of static electricity, which comprises a substrate, a film, a conductive drive block and a cantilever beam. A cavity is arranged on the upper part of the substrate, and the film is fixedly connected to the top surface of the substrate, and the film covers the cavity. , the conductive driving block is fixedly connected to the top surface of the film, the cantilever beam is fixedly connected to the top surface of the substrate, and the cantilever beam is located above the conductive driving block. The pressure sensor has a simple structure. The embodiment of the present invention also provides a working method of the pressure sensor, which makes full use of the principle of electrostatic induction and avoids the defects of the traditional pressure sensor. In occasions suitable for voltage and current testing, it is very convenient to use the sensor of this embodiment for pressure measurement.

Description

A pressure sensor using electrostatic principle and its working method

technical field

The invention relates to a pressure sensor, in particular to a pressure sensor utilizing the electrostatic principle and a working method thereof.

Background technique

Among the products realized by silicon micromachining technology, pressure sensors are the earliest developed category. Traditional pressure sensors include piezoresistive, capacitive, resonant, etc., which can be applied to different occasions according to their characteristics. The resistance of traditional pressure sensors has disadvantages such as temperature drift and difficulty in detecting tiny capacitances.

Contents of the invention

Technical problem: The technical problem to be solved by the present invention is to provide a pressure sensor using the electrostatic principle and its working method, so as to avoid the shortcomings of traditional pressure sensor resistance such as temperature drift and difficulty in detecting tiny capacitance.

Technical solution: In order to solve the above-mentioned technical problems, the technical solution adopted in the embodiment of the present invention is:

A pressure sensor using the electrostatic principle, including a substrate, a film, a conductive drive block and a cantilever beam. A cavity is arranged on the upper part of the substrate, and the film is fixedly connected to the top surface of the substrate, and the film covers the cavity. The conductive drive block The cantilever is fixedly connected to the top surface of the film, the cantilever is fixedly connected to the top of the substrate, and the cantilever is located above the conductive driving block.

As a preferred example, the cantilever beam includes a connecting part and a horizontal part, one end of the connecting part is fixedly connected to the horizontal part, the other end of the connecting part is fixedly connected to the top surface of the substrate, and the horizontal part is located directly above the conductive driving block.

As a preferred example, the conductive driving block is located directly above the cavity.

The embodiment of the present invention also provides a working method of the pressure sensor. The working method includes: when the external pressure is applied to the surface of the sensor, the film bends, the distance between the cantilever beam and the conductive drive block changes, and then the cantilever beam and the conductive drive block An excitation voltage is applied between the blocks, and an electrostatic attraction is generated between the cantilever beam and the conductive drive block. As the excitation voltage increases, the electrostatic attraction also increases; when the excitation voltage increases to a certain value, the cantilever beam and the conductive drive block The pull-in phenomenon occurs between them. At this time, the corresponding excitation voltage is the pull-in voltage. The current generated by the contact between the conductive drive block and the cantilever beam is the pull-in current. According to the pull-in current, the external pressure value.

Beneficial effects: compared with the prior art, the present invention has the following beneficial effects: the embodiment of the present invention has a simple structure. The pressure sensor of the embodiment of the present invention includes a substrate, a thin film, a conductive driving block and a cantilever beam. The conductive driving block of the embodiment of the present invention fully utilizes the principle of electrostatic induction, and avoids the defects of the traditional pressure sensor. In occasions suitable for voltage and current testing, it is very convenient to use the sensor of this embodiment for pressure measurement.

Description of drawings

Fig. 1 is a schematic structural diagram of an embodiment of the present invention.

In the figure, there are: a substrate 1 , a thin film 2 , a conductive driving block 3 , a cantilever beam 4 , and a cavity 101 .

detailed description

The technical solutions of the embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

As shown in FIG. 1 , a pressure sensor utilizing the electrostatic principle according to an embodiment of the present invention includes a substrate 1 , a film 2 , a conductive driving block 3 and a cantilever beam 4 . A cavity 101 is provided on the upper portion of the substrate 1 . The film 2 is fixedly connected to the top surface of the substrate 1 , and the film 2 covers the cavity 101 . The conductive drive block 3 is fixedly connected to the top surface of the film 2 . The cantilever beam 4 is fixedly connected to the top surface of the substrate 1 , and the cantilever beam 4 is located above the conductive driving block 3 .

In the pressure sensor of the above embodiment, the driving block 3 and the cantilever beam 4 constitute the upper and lower electrodes. During operation, when external pressure is applied to the surface of the sensor, the film 2 bends, the distance between the cantilever beam 4 and the conductive driving block 3 changes, and then an excitation voltage is applied between the cantilever beam 4 and the conductive driving block 3, and the cantilever beam 4 Electrostatic attraction is generated between the cantilever beam and the conductive drive block 3, and as the excitation voltage increases, the electrostatic attraction also increases; when the excitation voltage increases to a certain value, the cantilever beam and the conductive drive block will be attracted. The corresponding excitation voltage is the pull-in voltage, and the current generated by the contact between the conductive drive block 3 and the cantilever beam 4 is the pull-in current. According to the pull-in current, the external pressure value is obtained.

During the above working process, the current generated by contacting the driving block 3 and the cantilever beam 4 due to the pull-in phenomenon is the pull-in current I. The magnitude of the pull-in voltage and pull-in current is closely related to the initial distance g ₀ between the two plates. Since different pressures P will cause different deformations of the film 2, resulting in different sizes of g ₀ , so the excitation voltage V _in when the pull-in phenomenon occurs is also different. That is to say, there is a one-to-one correspondence between the excitation voltage V _in and the external pressure P. As shown in Table 1.

Table 1

The excitation voltage V _in when the pull-in phenomenon occurs External pressure P V _in1 P1 V _in2 P2 … …

As long as the excitation voltage _Vin is measured when the pull-in phenomenon occurs, the external pressure P can be measured to achieve the effect of pressure sensing.

In the above embodiments, the cantilever beam 4 may have various structures. Preferably, the cantilever beam 4 includes a connecting part and a horizontal part, one end of the connecting part is fixedly connected to the horizontal part, the other end of the connecting part is fixedly connected to the top surface of the substrate 1, and the horizontal part is located on the front of the conductive driving block 3. above. The cantilever beam 4 of this structure is simple in structure. An attraction phenomenon occurs between the horizontal part of the cantilever beam 4 and the conductive driving block 3 .

As a preferred example, the conductive driving block 3 is located right above the cavity 101 . The external pressure acts on the membrane 2, and the membrane 2 is located directly above the cavity 101, and can undergo obvious displacement. Therefore, the conductive driving block 3 is also located directly above the cavity 101 , so that the conductive driving block 3 and the cantilever beam 4 are prone to attract.

In the pressure sensor of the embodiment of the present invention, the thin film 2 on the substrate 1 is used as the pressure sensitive film. In the embodiment of the present invention, a conductive driving block and a cantilever beam are provided, and the conductive driving block is used as a conductor. In this way, when the cantilever beam is deformed, the electrostatic principle can be used to measure the pressure. In this embodiment, the electrostatic principle is used to conveniently convert the pressure quantity into an electrical quantity for measurement. That is to say, the measurement of pressure is converted into the measurement of current, which is easy to operate and suitable for various occasions where voltage and current are conveniently measured.

The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the art should understand that the present invention is not limited by the above-mentioned specific examples. The descriptions in the above-mentioned specific examples and the description are only to further illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention The invention also has various changes and improvements, and these changes and improvements all fall within the scope of the claimed invention. The protection scope of the present invention is defined by the claims and their equivalents.

Claims (4)

1. a kind of pressure sensor of utilization electrostatic principle, it is characterised in that the pressure sensor includes substrate (1), film (2), conductive drive block (3) and cantilever beam (4), the top of substrate (1) are provided with cavity (101), and film (2) is fixedly connected on substrate (1) top surface, and film (2) covering cavity (101), conductive drive block (3) are fixedly connected on the top surface of film (2), cantilever beam (4) top surface of substrate (1) is fixedly connected on, and cantilever beam (4) is located at the top of conductive drive block (3).

2. according to the pressure sensor of the utilization electrostatic principle described in claim 1, it is characterised in that described cantilever beam (4) Including connecting portion and horizontal part, one end of connecting portion is fixedly connected with horizontal part, and the other end of connecting portion is fixedly connected on substrate (1) top surface, and horizontal position is in the surface of conductive drive block (3).

3. according to the pressure sensor of the utilization electrostatic principle described in claim 1 or 2, it is characterised in that the conductive driving Block (3) is located at directly over cavity (101).

4. the method for work of pressure sensor described in a kind of claim 1, it is characterised in that the method for work includes：Work as the external world When pressure is applied to sensor surface, film (2) bends, and cantilever beam (4) and the spacing of conductive drive block (3) change Become, then apply driving voltage between cantilever beam (4) and conductive drive block (3), cantilever beam (4) and conduction drive block (3) it Between produce electrostatic attraction, with the increase of driving voltage, electrostatic attraction also increases；When driving voltage increases to certain value, make Occurs adhesive phenomenon between cantilever beam and conductive drive block, now corresponding driving voltage is pick-up voltage, conductive drive block (3) The electric current for occurring adhesive phenomenon and the generation that contacts with cantilever beam (4) is operating current, according to the operating current, is obtained Ambient pressure value.