CN100371695C - Piezoresistance type free field pressure sensor - Google Patents
Piezoresistance type free field pressure sensor Download PDFInfo
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- CN100371695C CN100371695C CNB2005100379818A CN200510037981A CN100371695C CN 100371695 C CN100371695 C CN 100371695C CN B2005100379818 A CNB2005100379818 A CN B2005100379818A CN 200510037981 A CN200510037981 A CN 200510037981A CN 100371695 C CN100371695 C CN 100371695C
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Abstract
The present invention relates to a piezoresistance type free field pressure sensor which is composed of a sensing assembly, a modulation circuit, a cable and a sensor casing, wherein the sensor casing has a structure of a streamlined body; the sensitive assembly is a silicon piezoresistance assembly. The compression surface of the sensitive assembly and the outer surface of the sensor which are flush with each other are installed, the compressed surface is outwards connected to the cable by the modulation circuit which is installed in a sensor cavity; the sensitive assembly is a silicon sensitive element which has a Wheatstone bridge; the front surface of the silicon sensitive element is communicated with the sensor cavity; the modulation circuit is composed of a temperature compensation circuit and a high frequency wideband amplification circuit. The cable is provided with a protective sleeve, and thermal insulation fillers are filled between the protective sleeve and the cable; the sensor casing is composed of a streamlined base seat and a tube cap; the streamlined base seat is in the shape of an acute angle cone; the tube cap is fixed to the tail part of the streamlined base seat in a suspending way. The present invention which is manufactured by that silicon piezoresistive pressure sensors are introduced to the research field of explosion mechanics has the characteristics of favorable consistency, low cost, low frequency, favorable properties, simple and convenient signal processing, etc.
Description
Technical Field
The invention relates to a free field pressure sensor, in particular to a silicon piezoresistive free field pressure sensor technology.
Background
The free field refers to a field having only a direct wave and no reflected wave, and actually refers to a field in which the reflected wave is negligible compared with the direct wave. Since the foreign 60 s of the 20 th century, piezoelectric free-field sensors were manufactured due to their excellent dynamic characteristics, and a simpler free-field piezoelectric pressure sensor was studied at the national institute of science and technology in the late 70 s and the early 80 s, and this technology was later assigned to the second radio of Yangzhou. The utility model of HZP free field piezoelectric pressure sensor is applied by improvement of Beijing university of science and technology in 28.12.1995, and the publication is granted at 11.6.1996.
The silicon piezoresistive pressure sensor is produced in the 50 th century, and is put into practical use with the maturity of integrated circuit technology, and the application fields of the silicon piezoresistive pressure sensor are continuously expanded with the development of design technology, information processing technology and micromachining technology.
Disclosure of Invention
The invention introduces the mature silicon piezoresistive pressure sensor into the research field of explosion mechanics, and manufactures the piezoresistive free field pressure sensor.
The technical scheme of the invention is as follows:
the utility model provides a piezoresistive free field pressure sensor, comprises sensitive subassembly, modulate circuit, output cable and sensor housing, its characterized in that, this sensor housing adopts streamlined body structure, and this sensitive subassembly adopts silicon piezoresistive subassembly, and this sensitive subassembly is installed at this sensor front end region levelly and smoothly to this output cable is received to this modulate circuit external connection in the sensor cavity through installing, wherein:
the sensitive component is characterized in that a monocrystalline silicon substrate is exposed out of an area outside a front sensitive part of a silicon sensitive element with a Wheatstone bridge structure, the monocrystalline silicon substrate and a PYREX glass fixed support ring are electrostatically sealed to form a silicon sensitive core seat, a gold wire inner lead is welded on a metallization layer of the silicon sensitive core seat, the end face of the glass fixed support ring is fixed with a core seat frame arranged at the front end area of a sensor cavity, the back surface of the sensitive element is used as a pressed surface to be flush with the surface of a sensor shell, the front surface of the silicon sensitive element is communicated with the sensor cavity, the core seat frame is simultaneously fixed with an adapter plate, the other end of the inner lead is welded on the adapter plate, an adapter wire is welded at the adapter plate part corresponding to the inner lead, the other end of the adapter wire is used as the input end of a conditioning circuit, and the strain resistance of the Wheatstone bridge has a low resistance value lower than 1K omega.
As a further improvement of the invention, the conditioning circuit is composed of a temperature compensation circuit and a high-frequency broadband amplifying circuit, and is integrally installed on the conditioning circuit board, the conditioning circuit board is fixed in the sensor cavity through a fixed plate frame, the high-frequency broadband amplifying circuit is composed of a two-stage amplifying circuit, the first-stage amplifying circuit adopts an amplifier AD8221 with a unit gain bandwidth as high as 800KHz, and utilizes 5 times of amplification factor, the second-stage amplifying circuit adopts amplifiers OP37 with a unit gain bandwidth as high as 30MHz and 10-40 times of amplification factor, and the high-frequency broadband amplifying circuit has a bandwidth as high as 100KHz, a rise time less than 1 muS and extremely low noise.
As a further improvement of the invention, the output cable is provided with a protective sleeve and a structure which is provided with heat insulation filler between the protective sleeve and the output cable, the output cable is sequentially sleeved with a line pressing cap, the protective sleeve, the heat insulation filler and the protective cap in a penetrating way, the line pressing cap is screwed on the tail part of the protective sleeve, and the protective cap is screwed on the line pressing cap.
As a further improvement of the invention, the sensor shell consists of a streamline base with an acute-angle conical front end and a pipe cap screwed on the tail part of the streamline base, and forms the sensor cavity, the silicon sensitive element is flush-mounted in a region of 1/3-2/5 of the front end of the streamline base through the core seat frame, and the sensor shell is made of stainless steel or aluminum alloy.
As a further improvement of the invention, the circular surface of the silicon sensitive element is phi 2mm or phi 4mm, the inner diameter of the glass supporting ring is phi 2mm or phi 4mm and the corresponding outer diameter is phi 5mm to phi 6mm or phi 7mm to phi 8mm, the internal lead of the gold wire is phi 25 mu m to phi 40 mu m, the leading-out point of the Wheatstone bridge is a force sensitive area with phi 2mm or phi 4mm, the conical head of the streamline base is 30-45 DEG, and the diameter of the pipe cap is chosen to be phi 20-phi 40mm.
The invention has the beneficial effects that:
because the full-bridge chip made of monocrystalline silicon is used as a sensitive element of the piezoresistive free field pressure sensor, the dynamic characteristic of the piezoresistive free field pressure sensor is improved through special design; the sensitive element and the shell of the piezoresistive free-field pressure sensor are assembled into a whole by a flush mounting method, and in order to enhance the amplitude and the precision of the output signal of the sensor, a circuit for temperature compensation and signal conditioning is assembled at the rear part of the shell to form standardized output, so that the piezoresistive free-field pressure sensor has good consistency and interchangeability. In order to enable the sensor to be capable of resisting heat generated by explosion shock waves, a protective sleeve is additionally arranged on an output cable of the piezoresistive free field pressure sensor to thermally shield the cable, so that the phenomenon that the sensor fails due to cable ablation in the test process at the initial stage is prevented.
Drawings
FIG. 1 is a schematic front view of the structure of the present invention;
FIG. 2 is a schematic top view of the structure of the present invention;
FIG. 3 is a schematic front view of a silicon sensor device according to the present invention;
FIG. 4 is a schematic front view of a silicon sensor according to the present invention;
FIG. 5 is a schematic top view of a silicon sensor according to the present invention;
fig. 6 is a schematic diagram of the conditioning circuit described in the present invention.
The following description is made with reference to fig. 1 to 5:
1-streamline base 10-pipe cap
2-silicon sensitive element 11-output cable
3-glass fixed support ring 12-line pressing cap
4-adapter plate 13-protective sleeve
5-core seat frame 14-heat insulation filling material
6-gold wire inner lead 15-monocrystalline silicon substrate
7-patch cord 16-insulating layer
8-fixed plate frame 17-strain resistor
9-Conditioning Circuit Board 18-metallization layer
Detailed Description
The following is further described in conjunction with figures 1 through 5:
the utility model provides a piezoresistive free field pressure sensor, comprises sensitive subassembly, modulate circuit, output cable and sensor housing, its characterized in that, this sensor housing adopts streamlined body structure, and this sensitive subassembly adopts silicon piezoresistive subassembly, and this sensitive subassembly is installed at this sensor front end region levelly and smoothly to this output cable is received to this modulate circuit external connection in the sensor cavity through installing, wherein:
the sensitive component is characterized in that a monocrystalline silicon substrate 15 is exposed out of the area outside the front sensitive part of a silicon sensitive element 2 with a Wheatstone bridge structure, the monocrystalline silicon substrate and a PYREX glass fixed support ring 3 are electrostatically sealed to form a silicon sensitive core seat, a metallized layer 18 of the silicon sensitive core seat is welded with a gold wire inner lead 6, the end face of the glass fixed support ring is fixed with a core seat frame 5 arranged at the front end area of a sensor cavity, the back face of the sensitive element is used as a pressed face to be flush with the surface of a sensor shell, the front face of the silicon sensitive element is communicated with the sensor cavity, the core seat frame is simultaneously fixed with an adapter plate 4, the other end of the inner lead is welded with the adapter plate, an adapter wire 7 is welded at the part of the adapter plate corresponding to the inner lead, the other end of the adapter wire is used as the conditioning input end of the circuit, and a strain resistor 17 of the Wheatstone bridge has a low resistance value lower than 1K.
The conditioning circuit is composed of a temperature compensation circuit and a high-frequency broadband amplifying circuit, and is integrally installed on a conditioning circuit board 9, the conditioning circuit board is fixed in a sensor cavity through a fixed plate frame 8, the high-frequency broadband amplifying circuit is composed of two stages of amplifying circuits, the first stage of amplifying circuit adopts an amplifier AD8221 with a unit gain bandwidth as high as 800KHz, and utilizes the 5-fold amplification factor, the second stage of amplifying circuit adopts an amplifier OP37 with a unit gain bandwidth as high as 30MHz and an amplification factor of 10-40 times, and the high-frequency broadband amplifying circuit has a bandwidth as high as 100KHz, a rise time smaller than 1 mu S and extremely low noise.
The output cable has a structure that a protective sleeve 13 and a heat insulation filler 14 are arranged between the protective sleeve and the output cable, the output cable is sequentially sleeved with a line pressing cap 12, the protective sleeve 13, the heat insulation filler 14 and a protective cap, the line pressing cap is screwed on the tail part of the protective sleeve, and the protective cap is screwed on the line pressing cap.
The sensor shell consists of a streamline base 1 with the front end in an acute conical shape and a pipe cap 10 screwed at the tail part of the streamline base, and forms a sensor cavity, the silicon sensitive element is flush mounted in a 1/3-2/5 area of the front end of the streamline base through the core frame, and the sensor shell is made of stainless steel or alloy aluminum.
The circular surface of the silicon sensitive element can be phi 2mm or phi 4mm, the inner diameter of the glass fixed support ring is phi 2mm or phi 4mm, the corresponding outer diameter is phi 5mm to phi 6mm or phi 7mm to phi 8mm, the inner lead of the gold wire is phi 25 mu m to phi 40 mu m, the leading-out point of the Wheatstone bridge is a force sensitive area with phi 2mm or phi 4mm, the conical head of the streamline base is 30-45 degrees, and the diameter of the pipe cap is phi 20-phi 40mm.
The specific manufacture of the silicon piezoresistive sensitive element comprises the following steps:
1. the general silicon piezoresistive sensitive element is manufactured by adopting a conventional integrated circuit process, the resistance value of the strain resistor is about 5 kilohms, the doping concentration is low, and temperature compensation is convenient to carry out; the silicon piezoresistive sensitive element adopts concentration doping which is two orders of magnitude higher than normal, so that the resistance value of the resistor is reduced to a degree lower than 1K omega; simultaneously, the invention removes the insulating layer in the ring edge area on the front surface of the sensitive element to ensure that the insulating layer is completely exposed out of the monocrystalline silicon substrate, then the monocrystalline silicon substrate is connected with the glass fixed support ring through electrostatic sealing or other methods to form a silicon sensitive core base, and finally, an inner lead with proper length is bonded on the metallization layer of the sensitive core base.
2. The pattern surface of the sensitive core seat is downward, the end surface of the fixed support ring of the sensitive core seat is tightly connected with the core seat frame by using an adhesive, the adapter plate is firmly adhered to the core seat frame by using the adhesive, the gold wire inner lead is welded at a proper position of the adapter plate, and the adapter wire with proper length and the inner lead are correspondingly welded on the adapter plate to form the silicon sensitive assembly.
3. Testing characteristics of the core base, performing temperature compensation and signal conditioning on the core base to manufacture a conditioning circuit board, welding an output cable and a patch cord at a proper position, installing the conditioning circuit board in a pipe cap, and connecting the pipe cap with the flow line base through threads;
4. the wire pressing cap is screwed into the tail part of the pipe cap, the protective sleeve with connecting threads is sleeved outside the output cable, the heat insulating material can be filled or wrapped in the middle, and the threads of the protective cap are screwed into the wire pressing cap, so that the manufacturing of the piezoresistive free field pressure sensor is completed.
Characteristic measurement of the present invention:
when the shock wave in the air or in water reaches the sensor, the shock wave rarely reflects and sweeps the silicon sensitive element 2 due to the streamline shape of the streamline pipe seat, and the signal measured by the silicon sensitive element 2 can be considered to be generated by a free field.
When the pressure generated by the free field shock wave is P, the output Δ V generated by the silicon sensor 2 is:
in the formula: II is the piezoresistive coefficient of the strain resistor 17 in the silicon sensitive element 2; r is the diameter or side length of the elastic membrane in the silicon sensitive element 2; r is 1 The distance from the position of the strain resistor to the center of the elastic membrane; h is the thickness of the elastic membrane in the silicon sensitive element 2; p is the pressure of the shock wave applied to the silicon sensor 2.
Since the piezoresistive coefficient pi is temperature-dependent, when the pressure P is constant, the temperature characteristic of the sensor needs to be compensated because pi changes the output of the sensor with the temperature; the full-scale output of the general piezoresistive pressure sensitive element is changed from tens to hundreds of millivolts, and the full-scale output of the sensor can be unified to 5VDC or 4-20 mADC after the conditioning circuit is applied. Thereby having good consistency and interchangeability.
Natural frequency f of piezoresistive free-field pressure sensor according to the invention 0 Given by the formula:
in the formula: e is the Young's modulus of the elastic diaphragm, and mu is the Poisson's ratio of the elastic diaphragm.
The invention has the characteristics that: the sensor has an extremely wide pressure measurement range from 10kPa to 100MPa, good low-frequency and high-frequency characteristics, low frequency can be started from 0Hz, and high frequency can reach more than 700 MHz; the piezoresistive pressure sensitive element has extremely short rise time of 0.3-2 mu s magnitude, and has good consistency and mass production capacity because the piezoresistive pressure sensitive element can be manufactured by adopting a semiconductor integrated circuit process; because the elastic element and the sensitive element of the piezoresistive transducer are both monocrystalline silicon chips, the piezoresistive transducer is convenient to flush and install, and the device can fully exert the good frequency response characteristic of the element.
Claims (7)
1. The utility model provides a piezoresistive free field pressure sensor, comprises sensitive subassembly, conditioning circuit, output cable and sensor housing, its characterized in that, this sensor housing adopts the streamlined body structure, and this sensitive subassembly adopts silicon piezoresistive subassembly, and this sensitive subassembly flushes and installs in this sensor front end region to this output cable is received outward through this conditioning circuit of installing in the sensor cavity, wherein:
the sensitive component is characterized in that a monocrystalline silicon substrate (15) is exposed in an area outside a front sensitive part of a silicon sensitive element (2) with a Wheatstone bridge structure, the monocrystalline silicon substrate and a PYREX glass fixing support ring (3) are electrostatically sealed to form a silicon sensitive core seat, a metallized layer (18) of the silicon sensitive core seat is welded with a gold wire inner lead (6) through a special gold wire ball welding machine, the end face of the glass fixing support ring is fixed with a core seat frame (5) arranged at the front end area of a sensor cavity, the back surface of the sensitive element is used as a pressed surface and is flush with the surface of a sensor shell, the front surface of the silicon sensitive element is communicated with the sensor cavity, the core seat frame is simultaneously fixed with an adapter plate (4), the other end of the inner lead is welded on the adapter plate, an adapter wire (7) is welded with the adapter plate at the end corresponding to the inner lead, and the other end of the adapter wire is used as the input end of the conditioning circuit.
2. A piezoresistive free-field pressure sensor according to claim 1, characterized in that the strain resistors (17) of the wheatstone bridge have a low resistance value below 1K Ω.
3. The piezoresistive free-field pressure sensor according to claim 1 or 2, wherein the conditioning circuit is composed of a temperature compensation circuit and a high-frequency broadband amplifying circuit, and is integrally mounted on a conditioning circuit board (9), the conditioning circuit board is fixed in the sensor cavity through a fixing board frame (8), the high-frequency broadband amplifying circuit is composed of two stages of amplifying circuits, the first stage of amplifying circuit adopts an amplifier AD8221 with a unit gain bandwidth of up to 800KHz, and utilizes 5 times of amplification factor, the second stage of amplifying circuit adopts amplifiers 0P37 with a unit gain bandwidth of up to 30MHz and 10-40 times of amplification factor, and the high-frequency broadband amplifying circuit has a bandwidth of up to 100KHz, a rise time of less than 1 μ S and extremely low noise.
4. A piezoresistive free field pressure sensor according to claim 1 or 2, wherein the outgoing cable has a protective sheath (13) and insulating filler (14) is provided between the sheath and the outgoing cable.
5. The piezoresistive free-field pressure sensor according to claim 4, wherein the output cable is sequentially threaded through a wire pressing cap (12), a protective sleeve (13), a heat insulating filler (14) and a protective cap, the wire pressing cap is screwed on the tail of the protective sleeve, and the protective cap is screwed on the wire pressing cap.
6. The piezoresistive free-field pressure sensor according to claim 2, wherein the sensor housing comprises a streamline base (1) with an acute conical front end and a pipe cap (10) screwed on the tail of the streamline base, and forms the sensor cavity, the silicon sensitive element is flush mounted on the region of 1/3-2/5 of the front end of the streamline base through the core frame, and the sensor housing is made of stainless steel or aluminum alloy.
7. A piezoresistive free-field pressure sensor according to claim 6, wherein the circular face of the silicon sensor is Φ 2mm or Φ 4mm, the internal diameter of the glass backbone ring is Φ 2mm or Φ 4mm and the corresponding external diameter is Φ 5mm to Φ 6mm or Φ 7mm to Φ 8mm, the internal lead of the gold wire is Φ 25 μm to Φ 40 μm, the exit point of the Wheatstone bridge is a force sensitive region of Φ 2mm or Φ 4mm, the taper of the base of the streamline is 30 ° to 45 °, and the diameter of the cap is selected from Φ 20 mm to Φ 40mm.
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| Application Number | Priority Date | Filing Date | Title |
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| CNB2005100379818A CN100371695C (en) | 2005-03-04 | 2005-03-04 | Piezoresistance type free field pressure sensor |
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| Application Number | Priority Date | Filing Date | Title |
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| CNB2005100379818A CN100371695C (en) | 2005-03-04 | 2005-03-04 | Piezoresistance type free field pressure sensor |
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| CN1828246A CN1828246A (en) | 2006-09-06 |
| CN100371695C true CN100371695C (en) | 2008-02-27 |
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Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102818670B (en) * | 2012-08-13 | 2014-04-16 | 西安近代化学研究所 | Explosion-field shock wave overpressure filter |
| CN102914404A (en) * | 2012-11-08 | 2013-02-06 | 中北大学 | Method for eliminating disadvantageous influences of explosion light on impact wave overpressure testing sensor |
| CN104390739A (en) * | 2014-11-26 | 2015-03-04 | 西安微纳传感器研究所有限公司 | Piezoresistive micro-melted high temperature pressure sensor and manufacturing method thereof |
| CN104748910B (en) * | 2015-03-04 | 2018-02-27 | 中国商用飞机有限责任公司 | Sensor bracket assembly for testing tire burst pressure |
| CN106644258B (en) * | 2016-12-19 | 2019-03-08 | 西安近代化学研究所 | A kind of shock wave free field survey laminated structure for shock tube calibration |
| CN109932109A (en) * | 2019-03-07 | 2019-06-25 | 胡波 | Microminiature quick response absolute pressure transducer |
| CN114199117A (en) * | 2021-12-09 | 2022-03-18 | 郭岳潘 | Digital bridge sensor |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2112146U (en) * | 1992-02-25 | 1992-08-05 | 北京理工大学 | Plunger type copper-manganese piezoelectric resistance transducer |
| CN2239619Y (en) * | 1995-12-28 | 1996-11-06 | 北京理工大学 | HZP free field voltage electrical pressure sensor |
| US20030177839A1 (en) * | 2002-03-22 | 2003-09-25 | Kabushiki Kaisha Toyota Chuo Kenkyusho | Force sensors |
-
2005
- 2005-03-04 CN CNB2005100379818A patent/CN100371695C/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2112146U (en) * | 1992-02-25 | 1992-08-05 | 北京理工大学 | Plunger type copper-manganese piezoelectric resistance transducer |
| CN2239619Y (en) * | 1995-12-28 | 1996-11-06 | 北京理工大学 | HZP free field voltage electrical pressure sensor |
| US20030177839A1 (en) * | 2002-03-22 | 2003-09-25 | Kabushiki Kaisha Toyota Chuo Kenkyusho | Force sensors |
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| CN1828246A (en) | 2006-09-06 |
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