WO2019242347A1

WO2019242347A1 - Wide-range wind speed sensor and manufacturing method therefor

Info

Publication number: WO2019242347A1
Application number: PCT/CN2019/078738
Authority: WO
Inventors: 秦明; 吴启强; 宋坤; 易真翔; 黄庆安
Original assignee: 东南大学
Priority date: 2018-06-21
Filing date: 2019-03-19
Publication date: 2019-12-26
Also published as: CN109001486B; CN109001486A

Abstract

The present invention relates to a wide-range wind speed sensor and manufacturing method therefor. The wide-range wind speed sensor comprises a substrate (1), an elastic thin film (2), a heating element (5), a raised table surface (6), a heat insulating layer (7), four pressure sensors (31), and four temperature sensors (41). On the basis of the design scheme of the present invention, the described hardware is combined to construct the wide-range wind speed sensor. Correspondingly, the present invention further relates to the manufacturing method for the wide-range wind speed sensor. Therefore, according to the whole technical solution, wind speed and wind direction data can be accurately measured under a low wind speed by using the principle of a thermal sensor; moreover, by using a piezoresistive effect, the wind speed and wind direction data can be accurately measured under a high wind speed; furthermore, by using a bulk-silicon micromachining technique, the process is reliable, batch manufacturing is easy, and the costs are low; in addition, a two-dimensional symmetrical structure is further used, and temperature drift is small.

Description

Wide-range wind speed sensor and manufacturing method thereof

Technical field

The invention relates to a wide-range wind speed sensor and a manufacturing method thereof, and belongs to the technical field of wind speed measurement.

Background technique

Wind speed and direction are very important parameters to characterize the meteorological situation. The detection of wind speed and direction has important effects on environmental monitoring, air conditioning, and industrial and agricultural production. Therefore, it is of great practical significance to quickly and accurately measure wind speed and direction. Traditional wind cups and wind vanes are currently widely used detection devices, but these devices are large in size, not sensitive enough for low wind speed measurement, and mechanical rotating structures are prone to wear; ultrasonic wind sensors are another type of commonly used wind sensors. High precision, but large size, high cost and other factors limit its application. Thermal wind sensors reflect wind speed information by measuring heat loss or thermal symmetry. This type of sensor is more sensitive to low wind speeds and the structure can be made small, but the small measurement range limits its use in two-dimensional wind speed measurement. Promotion application.

Summary of the Invention

The technical problem to be solved by the present invention is to provide a wide-range wind speed sensor, which combines the thermal film measurement principle and the wind pressure measurement principle organically, and can accurately realize the complete coverage of high and low wind speed measurement.

In order to solve the above technical problems, the present invention adopts the following technical solutions: The present invention designs a wide-range wind speed sensor, which is characterized by including a substrate, an elastic film, a heating element, a raised table surface, a heat insulation layer, four pressure sensors, and Four temperature sensors;

The center of the substrate is provided with through holes penetrating the upper and lower surfaces thereof. The shape and size of the elastic film are adapted to the shape and size of the through holes on the substrate. The elastic film is arranged in the through hole of the substrate, and the edge of the elastic film is round. Butt the inner edge of the through hole on the substrate for one round, and the upper surface of the elastic film is flush with the upper surface of the substrate;

The top surface of the raised mesa is parallel to the bottom surface. In the direction perpendicular to the top surface of the raised mesa, the projection of the top surface of the raised mesa is located inside the projection of the raised bottom surface, and the center of the raised mesa projection is at the center of its bottom surface. The position projections coincide with each other; the lower surface of the raised mesa is fixed at the center of the upper surface of the elastic film, and the center of the lower surface of the raised mesa and the center of the upper surface of the elastic film correspond to each other, along the Direction, the projection of the bottom surface of the convex table is located inside the elastic film projection;

Four pressure sensors are arranged around the center position of the upper surface of the elastic film, and are respectively embedded in the edge positions of the upper surface of the elastic film. Does not coincide with the position set by any pressure sensor;

The heat insulation layer covers the top surface and the side surfaces of the substrate, the elastic film, and the raised surface.

The heating element is fixedly arranged at the center of the top surface of the heat insulation layer corresponding to the top surface of the raised table surface. Four temperature sensors are arranged around the heating element, respectively at the position of the top surface of the heat insulation layer corresponding to the top surface of the raised table surface, and the four temperature sensors Orthogonal and symmetrical distribution around the heating element;

The four pressure sensors and the four temperature sensors correspond to each other one by one. When projected in the direction of the top surface of the raised mesa when viewed from the top, the center position of the top of the raised mesa is respectively the line where the temperature sensor is connected, and the center of the top of the raised mesa respectively. The position coincides with the straight line where the corresponding pressure sensor is connected.

As a preferred technical solution of the present invention, the material of the substrate and the material of the elastic film are the same as each other.

As a preferred technical solution of the present invention, the combination of the substrate and the elastic film is an integrated molding structure.

As a preferred technical solution of the present invention, the elastic film has a regular polygonal shape or a circular shape in a plan view along a top surface thereof.

As a preferred technical solution of the present invention, the projection of the raised mesa along a top surface thereof is a regular polygon or a circle.

Corresponding to the above technical solution, the technical problem to be solved by the present invention is to provide a method for manufacturing a wide-range wind speed sensor, which can efficiently and quickly implement the production of a wide-range wind speed sensor.

In order to solve the above technical problems, the present invention adopts the following technical solutions: The present invention devises a manufacturing method for a wide-range wind speed sensor, including the following steps:

Step A. Thermally bonding two oxidized silicon wafers to form a SOI thick film structure;

Step B. Photoetch the upper layer of silicon and form an elevated mesa using an anisotropic etching solution, and the etching will automatically stop on the silicon oxide film on the interface;

Step C. Spray lithography, and form four pressure sensors on the upper surface of the underlying silicon by ion implantation or diffusion of boron;

Step D. The silicon wafer is re-oxidized to form a heat insulation layer;

Step E. Using a stripping process, spray photolithography forms a pattern of the heating element and the four temperature sensors on the table, and then evaporates the metal Ni and strips it;

Step F. The etching window is opened on the back surface, and then the back surface is etched to form a deep groove. When the thickness of the underlying silicon film reaches the preset elastic film thickness, it stops. At this time, the release of the elastic film is completed.

Compared with the prior art, the wide-range wind speed sensor and the manufacturing method thereof according to the present invention have the following technical effects:

The wide-range wind speed sensor designed by the invention and the manufacturing method thereof adopt the thermal sensor principle to accurately measure the wind speed and wind direction data at a low wind speed; and use the piezoresistive effect to accurately measure the wind speed and wind direction data at a high wind speed; and use a bulk silicon micro Mechanical processing technology, reliable technology, easy batch production and low cost; not only that, it also uses a two-dimensional symmetrical structure with low temperature drift.

BRIEF DESCRIPTION OF THE DRAWINGS

1 is a top view of a wide-range wind speed sensor designed by the present invention;

FIG. 2 is a side view of the wide-range wind speed sensor designed by the present invention.

Among them, 1. substrate, 2. elastic film, 31. pressure sensor, 41. temperature sensor, 5. heating element, 6. raised table, 7. heat insulation layer

detailed description

The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings of the description.

As shown in FIG. 1 and FIG. 2, a wide-range wind speed sensor designed by the present invention, in actual application, specifically includes a substrate 1, an elastic film 2, a heating element 5, a raised table 6, an insulation layer 7, and four Pressure sensor 31 and four temperature sensors 41.

Wherein, the material of the substrate 1 and the elastic film 2 are the same as each other. Through holes are formed at the center of the substrate 1 through the upper and lower surfaces. The shape and size of the elastic film 2 are the same as those of the through holes on the substrate 1. Correspondingly, the elastic film 2 is disposed in the through hole of the substrate 1, and the edge of the elastic film 2 abuts the inner edge of the through hole on the substrate 1 once, and the upper surface of the elastic film 2 is flush with the upper surface of the substrate 1. The plan projection along its top surface is a regular polygon or a circle; in practical applications, the combination of the substrate 1 and the elastic film 2 may adopt an integrated molding structure.

The top projection of the raised table 6 is a regular polygon or a circle when viewed from above. The top surface of the raised table 6 is parallel to the bottom surface, and the projection of the top surface of the raised table 6 is located in a direction perpendicular to the top surface of the raised table 6. The inside of the projection of the raised surface 6 and the projection of the center position of the raised surface 6 and the projection of the center of the bottom surface coincide with each other; the lower surface of the raised surface 6 is fixed at the center of the upper surface of the elastic film 2 and the raised surface The center position of the lower surface 6 and the center position of the upper surface of the elastic film 2 correspond to each other, and the projection of the bottom surface of the projection table 6 is located inside the projection of the elastic film 2 in a direction perpendicular to the top surface of the projection table 6.

The four pressure sensors 31 surround the center position of the upper surface of the elastic film 2 and are respectively embedded in the edge positions of the upper surface of the elastic film 2. The four pressure sensors 31 are orthogonally symmetrically distributed around the center position of the upper surface of the elastic film 2 and convex. The position set by the lifting platform 6 does not coincide with the position set by any pressure sensor 31.

The heat insulation layer 7 covers the upper surface of the substrate 1, the upper surface of the elastic film 2, and the top surface and side surfaces of the raised mesa 6.

The heating element 5 is fixedly arranged at the center of the upper surface of the heat-insulating layer 7 corresponding to the top surface of the convex table 6; four temperature sensors 41 surround the heating element 5 and are respectively provided on the top surface of the heat-insulating layer 7 corresponding to the top surface of the convex table 6. Position, and the four temperature sensors 41 are orthogonally symmetrically distributed around the heating element 5.

The four pressure sensors 31 and the four temperature sensors 41 correspond to each other in a one-to-one manner, and the projections along the top surface of the convex table 6 are viewed from the top. The center of the top surface of the lifting platform 6 coincides with the straight line where the corresponding pressure sensor 31 is connected.

Corresponding to the technical solution of the wide-range wind speed sensor designed above, the present invention accordingly designs a method for manufacturing a wide-range wind speed sensor, which is characterized by including the following steps:

Step A. The two oxidized silicon wafers are thermally bonded to form a SOI thick film structure.

Step B. Photoetch the upper silicon layer and form an elevated mesa 6 with an anisotropic etching solution. The etching stops automatically on the silicon oxide film at the interface.

Step C. Spray lithography, and form four pressure sensors 31 on the upper surface of the lower silicon layer by ion implantation or diffusion of boron.

Step D. The silicon wafer is re-oxidized to form a heat-insulating layer 7.

Step E. Using a lift-off process, spray photolithography is used to form the pattern of the heating element 5 and the four temperature sensors 41 on the mesa, and then the metal Ni is evaporated and peeled off.

Step F. The back surface photolithography opens an etching window, and then the back surface is etched to form a deep groove. When the thickness of the underlying silicon film reaches the preset thickness of the elastic film 2, it stops. At this time, the release of the elastic film 2 is completed.

Applying the above-designed wide-range wind speed sensor in practical application, when there is no wind, the heating element 5 works to form a thermal field with the center of the film as the center. The temperature sensors 41 on the four sides are symmetrically distributed, so the two temperatures are opposite The temperature difference of the sensor 41 is 0; when a small wind blows from the sensor surface, the thermal field will change, and the temperature measured by the downstream temperature sensor 41 is higher than the output of the upstream temperature sensor 41. As a result, the temperature difference changes with the size of the wind. At this time, the wind pressure of the small wind on the wind-sensitive slope of the raised table 6 is small, and the stress transmitted to the pressure sensor 31 is also small. The measurement of wind is mainly achieved by the temperature difference output by the temperature sensor 41. When the wind is large, the temperature difference caused by the thermal temperature field becomes smaller and smaller. The accuracy and sensitivity of the above-mentioned method of temperature difference measurement by the temperature sensor 41 begin to decrease. However, the pressure of the wind on the side of the raised table surface has increased sharply (the wind pressure is proportional to the square of the wind speed). This wind pressure is transferred to the pressure sensor 31, which causes the pressure sensor 31 to produce a larger output. The pressure sensor 31 downstream of the column detects a large tensile stress, and the pressure sensor 31 upstream detects a large compressive stress. The aforementioned stress change is detected by the resistance change of the pressure sensor 31. With appropriate algorithms, information on wind speed and direction can be obtained.

Specifically, when the sensor is working, the heating element 5 is heated to heat the air on the surface to generate a thermal temperature field. When there is no wind, the temperature sensors 41 have the same temperature due to the symmetrical distribution, and the difference between the opposite two temperature sensors 41 0; at low wind speeds, the temperature field changes with wind direction and wind speed. The temperature at the downstream end of heating element 5 is higher than the upstream end. The temperature difference from the relative temperature sensor 41 is not 0. It is assumed that the wind speed and wind direction cause the X direction. The temperature difference output is Tx and the temperature difference output in the Y direction is Ty.

Monotonic correlation; the wind direction is proportional to arctg (Tx / Ty), so the information of wind speed and wind direction can be obtained by calculation; when the wind speed is large, the raised table 6 is subjected to lateral and longitudinal pressure by the wind pressure, and the pressure is passed through the elasticity The film 2 is transferred to a pressure sensor 31. Similarly, due to the different stress directions of the elastic film 2, there is a difference between the downstream piezoresistance and the upstream piezoresistive output, that is, the piezoresistive output difference X in the X direction and the piezoresistive output difference Vy in the Y direction are related to the wind speed and direction. . Using a formula similar to the temperature difference output, data on wind speed and direction can be obtained. The above two outputs are considered in combination. For example, a suitable wind speed conversion point is set. When the wind speed is lower than the conversion point, the thermal temperature difference is used to calculate the wind speed and wind direction. When the wind speed is higher than the conversion point, the piezoresistive output difference is used to calculate the wind speed and wind direction data.

The wide-range wind speed sensor designed by the above technical solution uses the principle of a thermal sensor to accurately measure wind speed and direction data at low wind speeds; and the piezoresistive effect enables precise measurement of wind speed and direction data at high wind speeds; and uses bulk silicon micro-machining technology , Reliable technology, easy batch production and low cost; not only that, but also uses a two-dimensional symmetrical structure, small temperature drift.

The embodiments of the present invention have been described in detail above with reference to the drawings, but the present invention is not limited to the above embodiments, and can be made without departing from the spirit of the present invention within the scope of the knowledge possessed by a person of ordinary skill in the art. Various changes.

Claims

A wide-range wind speed sensor is characterized in that it includes a substrate (1), an elastic film (2), a heating element (5), a raised table (6), a thermal insulation layer (7), and four pressure sensors (31 ) And four temperature sensors (41);

The substrate (1) is provided with through holes penetrating the upper and lower surfaces of the center thereof. The shape and size of the elastic film (2) are adapted to the shape and size of the through holes on the substrate (1). The elastic film (2) Set in the through hole of the substrate (1), the edge of the elastic film (2) abuts the inner edge of the through hole on the substrate (1) once, and the upper surface of the elastic film (2) is flush with the upper surface of the substrate (1) ;

The top surface of the raised table surface (6) is parallel to the bottom surface, and the projection of the top surface of the raised table surface (6) is located inside the projection of the raised surface of the raised table surface (6) in a direction perpendicular to the top surface of the raised table surface (6). And the projection of the center position of the top surface of the raised table (6) coincides with the projection of the center position of the bottom surface of the raised table; the lower surface of the raised table (6) is fixed at the center of the upper surface of the elastic film (2), and the raised table (6) The center position of the lower surface and the center position of the upper surface of the elastic film (2) correspond to each other, and the projection of the bottom surface of the projection table (6) is located inside the projection of the elastic film (2) in a direction perpendicular to the top surface of the projection table (6);

Four pressure sensors (31) surround the center position of the upper surface of the elastic film (2), are respectively embedded in the edge positions of the upper surface of the elastic film (2), and the four pressure sensors (31) surround the upper surface of the elastic film (2). The center position is orthogonally symmetrically distributed, and the position set by the raised table (6) does not coincide with the position set by any pressure sensor (31);

The heat-insulating layer (7) covers the upper surface of the substrate (1), the upper surface of the elastic film (2), and the top surface and side surfaces of the raised mesa (6);

The heating element (5) is fixedly arranged on the upper surface of the heat-insulating layer (7) corresponding to the center of the top surface of the raised table (6). Four temperature sensors (41) are respectively arranged on the heat-insulating layer (5) around the heating element (5). 7) The position of the upper surface corresponding to the top surface of the raised table (6), and the four temperature sensors (41) are distributed orthogonally and symmetrically around the heating element (5);

The four pressure sensors (31) and the four temperature sensors (41) correspond to each other one by one, and the projection along the direction of the top surface of the raised table (6) when viewed from the top, the center position of the top surface of the raised table (6) is respectively to each temperature sensor ( 41) The lines where the lines are located coincide with the lines where the center of the top surface of the raised table (6) reaches the line where the corresponding pressure sensor (31) is located.
The wide-range wind speed sensor according to claim 1, wherein the material of the substrate (1) and the material of the elastic film (2) are the same as each other.
The wide-range wind speed sensor according to claim 2, characterized in that the combination of the substrate (1) and the elastic film (2) is an integrally formed structure.
The wide-range wind speed sensor according to claim 1, wherein the elastic film (2) is a regular polygon or a circle when viewed from above the top surface of the elastic film (2).
A wide-range wind speed sensor according to claim 1, characterized in that the top projection of the raised table (6) along its top surface is regular polygon or circular.
A method for manufacturing a wide-range wind speed sensor according to any one of claims 1 to 5, comprising the following steps:

Step A. Thermally bonding two oxidized silicon wafers to form a SOI thick film structure;

Step B. Photoetch the upper layer of silicon and form an elevated mesa (6) with an anisotropic etching solution, and the etching will automatically stop on the silicon oxide film on the interface;

Step C. Spray lithography, and form four pressure sensors (31) on the upper surface of the lower silicon layer by ion implantation or diffusion of boron.

Step D. The silicon wafer is re-oxidized to form a heat insulation layer (7);

Step E. Adopt a lift-off process, spray the photolithography to form the pattern of the heating element (5) and the four temperature sensors (41) on the mesa, then evaporate the metal Ni and lift off;

Step F. The etching window is opened on the backside lithography, and then the backside is etched to form a deep groove. When the thickness of the underlying silicon film reaches the thickness of the preset elastic film (2), it stops. At this time, the release of the elastic film (2) is completed.