A kind of pressure sensor with high temperature resistance and high frequency response that flushes encapsulation
Technical field
The present invention relates to art of pressure sensors, be specifically related to a kind of pressure sensor with high temperature resistance and high frequency response that flushes encapsulation.
Background technology
Pressure transducer is widely used in every field such as Aero-Space, national defence, industry, petrochemical complex as one of the most frequently used sensor.In recent years, along with the development of China's Aero-Space and war industry, surpass 100KHz for a kind of frequency response, the high temperature resistant requirement that reaches the pressure transducer more than 100 ℃ is more and more urgent.Requirement can accurately be measured the transient pressure in aviation or the blasting process, because the undistorted waveform of the accurate measurement of transient pressure and dynamic pressure is described in scientific experiment, the design optimization process of argumentation very important effect is arranged.Thereby the pressure transducer with wide frequency response, good dynamic property becomes the focus of modern measuring technology.And the gordian technique of external product is carried out blockade on new techniques to domestic always, and, high frequency sound pressure transducer implementation outlet restriction high temperature resistant to the high precision relevant with national defence fields such as military affairs, Aero-Space.
The sensor of current gaging pressure mainly contains strain-type, piezoelectric type and pressure resistance type, and the natural frequency that traditional strain pressure transducer is too low does not satisfy the needs of test already; The piezoelectric pressure indicator that is used for dynamic pressure measurement also has a lot of shortcomings of self, piezoelectric pressure indicator is output as charge signal, some piezoelectric needs moisture preventive measure, the charge leakage phenomenon appears easily, the subsequent process circuit more complicated, need to adopt high input impedance circuit or charge amplifier to overcome this defective, the cost height, and the easy noise that is difficult to overcome of introducing, piezoelectric pressure indicator can only measure dynamic pressure signal, for static and quasi-static pressure signal, it is powerless just to seem; Utilize the piezoresistive effect of silicon and conventional diffusion silicon piezoresistance type pressure sensor that integrated circuit technique is made to have highly sensitive, dynamic response is fast, the measuring accuracy height, good stability, characteristics such as be easy to miniaturization and can be mass-produced, but, its force sensing resistance and silicon base isolate because being p-n junctions, in serviceability temperature during greater than 80 ℃, because of p-n junction produces mis-behave even the inefficacy that leakage current makes sensor, thereby, the conventional diffusion silicon pressure sensor is difficult to solve the pressure survey difficult problem of high temperature more than 80 ℃, and the existing sensors chip all is encapsulated in metal shell inside, so just there has been a cavity, because the influence of tube chamber effect has reduced the frequency response of sensor.
Summary of the invention
In order to overcome the shortcoming of above-mentioned prior art, the object of the present invention is to provide a kind of pressure sensor with high temperature resistance and high frequency response that flushes encapsulation, be used to measure dynamic or static pressure signal, have advantage high temperature resistant, high frequency sound.
In order to achieve the above object, the technical solution used in the present invention is:
A kind of pressure sensor with high temperature resistance and high frequency response that flushes encapsulation, comprise pressure chip 1, pressure chip 1 combines by the bottom surface of electrostatic bonding and glass ring 2, the top of the bottom outlet of the top and metal base 5 of glass ring 2 is bonding, metal base 5 inside are cavity, dispose two platforms at cavity middle part and bottom, high temperature card extender 3 is separately fixed on the platform at bottom and middle part with high temperature built-up circuit compensating plate 4, pressure chip 1 is connected by five spun gold lead-in wires 13 with high temperature switching circuit board 3, high temperature card extender 3 links to each other by five high temperature wires 12 with high temperature built-up circuit compensating plate 4, four leads that four-core high temperature wire 10 is drawn respectively with high temperature built-up circuit compensating plate 4 on A ', B ', four nodes of C ' and D ' link together, the top of metal base 5 is connected with the bottom of metal shell 6, metal shell 6 tops are connected with solidus cap 7, metal shell 6 central upper portion dispose a hole 9, solidus cap 7 disposes center pit 8, and four-core high temperature wire 10 passes from the hole 9 of metal shell 6 and the center pit 8 of solidus cap 7.
The diameter of described center pit 8 is less than the diameter in hole 9, and center pit 8 overlaps with the center in hole 9.
Dispose the resistance R of four equivalences on the described pressure chip 1, and form the open loop Wheatstone bridge circuit, its termination links to each other with five spun golds lead-in wires 13 respectively with node A, B, C, D and E between resistance R.
Dispose compensating resistance 11 and A ', B ', C ', D ', five nodes of E ' on the described high temperature built-up circuit compensating plate 4, node A ' is connected by compensating resistance 11 with E ', node A ', B ', C ', D ' and E ' are connected with five high temperature wires 12 respectively, wherein the spun gold lead-in wire 13 that connects out from the A node links to each other with the high temperature wire 12 that is connected out from A ' node, and other each nodes are also corresponding mutually.
Described pressure chip 1 adopts the quick chip of high temperature resistant pressure resistance of SOI material development.
Packaged type has adopted and has flushed packaged type, and promptly when encapsulation, pressure chip 1 flushes with the lower surface of metal base 5.
Principle of work of the present invention is: after pressure chip 1 is experienced the pressure of extraneous medium, pressure signal is changed into voltage signal, voltage signal is delivered to high temperature built-up circuit compensating plate 4 by spun gold lead-in wire 13, high temperature card extender 3 and high temperature wire 12 successively, after the compensation through compensating resistance 11 on the high temperature built-up circuit compensating plate 4, voltage signal is exported by four-core high temperature wire 10.
Because pressure chip of the present invention 1 adopts the quick chip of high temperature resistant pressure resistance, and the present invention adopted and flushed packaged type, so have advantage high temperature resistant, high frequency sound, is used to measure dynamic or static pressure signal.
Description of drawings
Fig. 1 is a structure cut-open view of the present invention.
Fig. 2 is the circuit diagram of pressure chip 1.
Fig. 3 is the circuit diagram of high temperature built-up circuit compensating plate 4.
Specific implementation method
Below in conjunction with accompanying drawing the present invention is elaborated.
With reference to accompanying drawing 1, a kind of pressure sensor with high temperature resistance and high frequency response that flushes encapsulation, comprise pressure chip 1, pressure chip 1 combines by the bottom surface of electrostatic bonding and glass ring 2, the top of the bottom outlet of the top and metal base 5 of glass ring 2 is bonding, metal base 5 inside are cavity, dispose two platforms at cavity middle part and bottom, high temperature card extender 3 is separately fixed on the platform at bottom and middle part with high temperature built-up circuit compensating plate 4, pressure chip 1 is connected by five spun gold lead-in wires 13 with high temperature switching circuit board 3, high temperature card extender 3 links to each other by five high temperature wires 12 with high temperature built-up circuit compensating plate 4, four leads that four-core high temperature wire 10 is drawn respectively with high temperature built-up circuit compensating plate 4 on A ', B ', four nodes of C ' and D ' link together, the top of metal base 5 is connected with the bottom of metal shell 6, metal shell 6 tops are connected with solidus cap 7, metal shell 6 central upper portion dispose a hole 9, solidus cap 7 disposes center pit 8, four-core high temperature wire 10 passes from the hole 9 of metal shell 6 and the center pit 8 of solidus cap 7, plays the fixedly effect of four-core high temperature wire 10.
The diameter of described center pit 8 is less than the diameter in hole 9, and center pit 8 overlaps with the center in hole 9.
With reference to accompanying drawing 2, dispose the resistance R of four equivalences on the described pressure chip 1, and form the Wheatstone bridge circuit of open loop, and purpose is for the voltage signal to sensor output compensates, its termination links to each other with five spun golds lead-in wires 13 respectively with node A, B, C, D and E between resistance R.
With reference to accompanying drawing 3, dispose compensating resistance 11 and A ' on the described high temperature built-up circuit compensating plate 4, B ', C ', D ', five nodes of E ', node A ' is connected by compensating resistance 11 with E ', node A ', B ', C ', D ' is connected with five high temperature wires 12 respectively with E ', wherein the spun gold lead-in wire 13 that connects out from the A node links to each other with the high temperature wire 12 that is connected out from A ' node, other each nodes are also corresponding mutually, compensating resistance 11 is used for the voltage signal of compensatory pressure chip 1 output, after the compensation, be communicated with by compensating resistance 11 between A and the E, formed the Wheatstone bridge circuit of a closure.
Described pressure chip 1 adopts the quick chip of high temperature resistant pressure resistance of SOI material development, and purpose is passed through SiO exactly
2Insulation course is kept apart the testing circuit layer and the silicon base of the quick chip of power, has avoided the leakage current generating between the testing circuit and substrate under the high temperature, and the high-temperature stability of the quick chip of raising power makes working temperature can bring up to 200 ℃.
Packaged type has adopted and has flushed packaged type, and promptly when encapsulation, pressure chip 1 flushes with the lower surface of metal base 5, and measured medium is acted directly on the pressure chip 1, thereby has avoided the influence of tube chamber effect.
Principle of work of the present invention is: by the resistance R 1 of four equivalences and form Wheatstone bridge circuit, do not do the time spent when stressing on pressure chip 1, Wheatstone bridge is in equilibrium state, no-voltage output; When being under pressure, pressure chip 1 does the time spent, Wheatstone bridge out of trim and output voltage signal, and the voltage and the pressure of output are proportional, after pressure chip 1 is experienced the pressure of extraneous medium, pressure signal is changed into voltage signal, voltage signal is by spun gold lead-in wire 13, high temperature card extender 3 and high temperature wire 12 are delivered to high temperature built-up circuit compensating plate 4, after the compensation through compensating resistance 11 on the high temperature built-up circuit compensating plate 4, by four-core high temperature wire 10 voltage signal is exported, because pressure chip 1 adopts the quick chip of high temperature resistant pressure resistance of SOI material development, its Young modulus is very high, add the small structure of micromachine electronic system self, so its natural frequency is very high, not only obtain high frequency sound, it is high to the broadband response near natural frequency to be low to moderate zero-frequency, and there is the rise time that is low to moderate submicrosecond to reach very level and smooth amplitude-versus-frequency curve, behind pressure chip 1 and glass ring 2 electrostatic bondings, form circular flat film, based on theoretical analysis, the response frequency of sensor depends mainly on encapsulating structure and mounting means, the present invention takes to flush packaged type, measured medium is acted directly on the chip, thereby avoided the influence of tube chamber effect, reduced because the influence that the sensor frequency response that encapsulation causes reduces.
In the accompanying drawing: 1 is pressure chip; 2 is glass ring; 3 is the high temperature keyset; 4 is high temperature built-up circuit compensating plate; 5 is metal base; 6 is metal shell; 7 is the solidus cap; Hole centered by 8; 9 is the hole; 10 is the four-core high temperature wire; 11 is compensating resistance; 12 is high temperature wire; 13 are the spun gold lead-in wire; R is resistance; A, B, C, D, E, A ', B ', C ', D ', E ' are node.