CN112294279A - Integrated invasive blood pressure sensor - Google Patents
Integrated invasive blood pressure sensor Download PDFInfo
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- CN112294279A CN112294279A CN202011177844.5A CN202011177844A CN112294279A CN 112294279 A CN112294279 A CN 112294279A CN 202011177844 A CN202011177844 A CN 202011177844A CN 112294279 A CN112294279 A CN 112294279A
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- 230000036772 blood pressure Effects 0.000 title claims abstract description 51
- 239000010409 thin film Substances 0.000 claims abstract description 73
- 239000010408 film Substances 0.000 claims abstract description 56
- 229920000106 Liquid crystal polymer Polymers 0.000 claims abstract description 36
- 239000004977 Liquid-crystal polymers (LCPs) Substances 0.000 claims abstract description 35
- 238000000034 method Methods 0.000 claims abstract description 34
- 239000007788 liquid Substances 0.000 claims abstract description 28
- 238000004806 packaging method and process Methods 0.000 claims abstract description 28
- 230000008569 process Effects 0.000 claims abstract description 27
- 230000008859 change Effects 0.000 claims abstract description 6
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 24
- 239000012528 membrane Substances 0.000 claims description 18
- 238000006243 chemical reaction Methods 0.000 claims description 15
- 238000005538 encapsulation Methods 0.000 claims description 12
- 239000004408 titanium dioxide Substances 0.000 claims description 12
- 230000009471 action Effects 0.000 claims description 11
- 238000004891 communication Methods 0.000 claims description 11
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 10
- 229910052719 titanium Inorganic materials 0.000 claims description 10
- 239000010936 titanium Substances 0.000 claims description 10
- 239000000758 substrate Substances 0.000 claims description 9
- 230000008054 signal transmission Effects 0.000 claims description 4
- 230000003321 amplification Effects 0.000 claims description 3
- 238000001914 filtration Methods 0.000 claims description 3
- 238000003199 nucleic acid amplification method Methods 0.000 claims description 3
- 238000005070 sampling Methods 0.000 claims description 2
- 239000012530 fluid Substances 0.000 claims 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 10
- 229910052710 silicon Inorganic materials 0.000 description 10
- 239000010703 silicon Substances 0.000 description 10
- 238000005516 engineering process Methods 0.000 description 4
- 238000005259 measurement Methods 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 210000004369 blood Anatomy 0.000 description 2
- 239000008280 blood Substances 0.000 description 2
- 238000009530 blood pressure measurement Methods 0.000 description 2
- 210000001124 body fluid Anatomy 0.000 description 2
- 239000010839 body fluid Substances 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/02—Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
- A61B5/021—Measuring pressure in heart or blood vessels
- A61B5/0215—Measuring pressure in heart or blood vessels by means inserted into the body
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/02—Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
- A61B5/021—Measuring pressure in heart or blood vessels
- A61B5/0215—Measuring pressure in heart or blood vessels by means inserted into the body
- A61B5/02156—Calibration means
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- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Cardiology (AREA)
- Heart & Thoracic Surgery (AREA)
- Molecular Biology (AREA)
- Physiology (AREA)
- Biophysics (AREA)
- Pathology (AREA)
- Engineering & Computer Science (AREA)
- Biomedical Technology (AREA)
- Vascular Medicine (AREA)
- Medical Informatics (AREA)
- Physics & Mathematics (AREA)
- Surgery (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Measuring Pulse, Heart Rate, Blood Pressure Or Blood Flow (AREA)
- Measuring Fluid Pressure (AREA)
Abstract
The invention provides an integrated invasive blood pressure sensor, comprising: the thin film piezoresistive bridge is configured as a Wheatstone balanced bridge and consists of two interdigital thin film piezoresistors which are not connected with each other and two single-strip thin film piezoresistors which are not connected with each other, and when the resistance values of the two interdigital thin film piezoresistors are stable values, two voltages output by the thin film piezoresistive bridge are equal; an integrated chip configured to process the voltage output by the thin film piezoresistive bridge; the liquid crystal polymer comprises a first packaging area and a second packaging area, the first packaging area bears two interdigital film piezoresistors, the second packaging area bears two single strip film piezoresistors and the integrated chip, and the liquid crystal polymer comprises: the bottom of the first packaging area is a U-shaped pressure acting cavity, the pressure acting cavity is in contact with liquid, and pressure formed by the liquid is transmitted to the interdigital thin film piezoresistor through the pressure acting cavity so as to change the resistance value of the interdigital thin film piezoresistor.
Description
Technical Field
The invention relates to the technical field of blood pressure sensors, in particular to an integrated invasive blood pressure sensor.
Background
The silicon-based piezoresistive pressure sensing technology is compatible with the integrated circuit process and is easy to realize miniaturization, so the silicon-based piezoresistive pressure sensing technology is widely applied to the field of invasive blood pressure sensors. However, such sensors have the disadvantages of poor linearity, small measurement range, and additional external wired circuit design required in the application process, so that they are limited in the application process. For example, the resistance of the bridge arm resistor in different silicon processes deviates from the nominal value by 20%, which causes a large zero offset of the bridge output, thereby causing a large linearity error. Various methods for optimizing the performance of the pressure sensor exist at present, including solving the linearity problem by using a zero-pressure offset compensation resistance technology, correcting a film resistor network by using laser, compensating an external resistor and the like; and shielding wires are adopted in signal transmission to reduce transmission interference and the like. However, no matter which process method is adopted, the problems caused by the defects of non-uniform thickness of the silicon cup, chamfer angle of the silicon cup, large thickness tolerance of the silicon film and the like in the semiconductor silicon process are difficult to completely overcome. Meanwhile, the use of the process compensation method and the anti-interference measures both need to involve additional multiple process technologies, and finally the product yield of the invasive blood pressure sensor is reduced.
Disclosure of Invention
The invention aims to provide an integrated invasive blood pressure sensor, which aims to solve the problem that the bridge output of the existing invasive blood pressure sensor has larger zero offset to cause linear error.
In order to solve the above technical problems, the present invention provides an integrated invasive blood pressure sensor, comprising:
the thin film piezoresistive bridge is configured as a Wheatstone balanced bridge and consists of two interdigital thin film piezoresistors which are not connected with each other and two single-strip thin film piezoresistors which are not connected with each other, and when the resistance values of the two interdigital thin film piezoresistors are stable values, two voltages output by the thin film piezoresistive bridge are equal;
an integrated chip configured to process the voltage output by the thin film piezoresistive bridge;
the liquid crystal polymer comprises a first packaging area and a second packaging area, the first packaging area bears two interdigital film piezoresistors, the second packaging area bears two single strip film piezoresistors and the integrated chip, and the liquid crystal polymer comprises:
the bottom of the first packaging area is a U-shaped pressure acting cavity, the pressure acting cavity is in contact with liquid, and pressure formed by the liquid is transmitted to the interdigital thin film piezoresistor through the pressure acting cavity so as to change the resistance value of the interdigital thin film piezoresistor.
Optionally, in the integrated invasive blood pressure sensor, the interdigital film piezoresistance includes a first piezoresistive element and a second piezoresistive element, wherein:
the first piezoresistive assembly and the second piezoresistive assembly are both comb-shaped, and the comb teeth of one of the first piezoresistive assembly and the second piezoresistive assembly are inserted into the teeth of the other one of the first piezoresistive assembly and the second piezoresistive assembly to form an intersecting arrangement.
Optionally, in the integrated invasive blood pressure sensor, the interdigital film piezoresistor and the single strip film piezoresistor both include a titanium film layer and a titanium dioxide film which are stacked,
the titanium thin film layer is disposed between the substrate of the liquid crystal polymer and the titanium dioxide thin film;
the resistance values of the two interdigital film piezoresistors and the two single strip film piezoresistors are consistent.
Optionally, in the integrated invasive blood pressure sensor, the method further includes:
a first encapsulation layer configured to seal the first encapsulation area to form a first cavity within which the two interdigitated membrane piezoresistors are housed;
and the second packaging layer is configured to seal the second packaging area to form a second cavity, and the two single-strip film piezoresistors and the integrated chip are accommodated in the second cavity.
Optionally, in the integrated invasive blood pressure sensor, the first cavity is filled with an insulating liquid, and the insulating liquid conducts the pressure on the surface of the first cavity to the two interdigital membrane piezoresistors.
Optionally, in the integrated invasive blood pressure sensor, the integrated chip is integrated on the substrate of the liquid crystal polymer through a CMOS process, including:
a differential operational amplifier circuit configured to amplify the voltage generated by the thin film piezoresistive bridge to form an analog amplified signal;
the analog-to-digital conversion circuit is configured to convert the analog amplification signal into a digital signal after filtering, sampling and holding and encoding;
a communication circuit configured to transmit the digital signal to a receiving device;
the calibration digital-to-analog conversion circuit is configured to adjust the voltage output by the differential operational amplifier circuit to zero when the pressure action cavity does not receive the pressure of the liquid;
and the state machine is configured to process the digital signal, judge whether the calibration digital-to-analog conversion circuit is calibrated in place according to the digital signal and control the signal transmission of the communication circuit.
Optionally, in the integrated invasive blood pressure sensor, the communication circuit includes an SPI interface, an I2C interface, a USB interface, a UART interface, an RS-485 interface, a CAN-bus interface, and/or a radio frequency chip.
Optionally, in the integrated invasive blood pressure sensor, the differential operational amplifier circuit is a chopper-stabilized operational amplifier.
Optionally, in the integrated invasive blood pressure sensor, the thin film piezoresistive bridge further includes a constant current source formed by an MOS transistor.
Optionally, in the integrated invasive blood pressure sensor, in a calibration process, the calibration digital-to-analog conversion circuit outputs an analog voltage, the analog voltage is applied to any one of the joints between the two interdigital film piezoresistors and the single strip film piezoresistor, and the analog voltage is adjusted to equalize the two voltages output by the film piezoresistor bridge.
In the integrated invasive blood pressure sensor provided by the invention, a thin film piezoresistive bridge is formed by two mutually unconnected interdigital thin film piezoresistors and two mutually unconnected single-strip thin film piezoresistors, a first packaging area carries the two interdigital thin film piezoresistors, a second packaging area carries the two single-strip thin film piezoresistors and the integrated chip, the bottom of the first packaging area is a U-shaped pressure action cavity which is contacted with liquid, and the pressure formed by the liquid is transmitted to the interdigital thin film piezoresistors through the pressure action cavity so as to change the resistance value of the interdigital thin film piezoresistors, so that the pressure sensitive resistors designed by adopting an interdigital structure are formed into the Wheatstone bridge, the matching of the pressure sensitive resistors is more favorably realized in the process of preparation, and the zero point balance of the thin film piezoresistors bridge is ensured to the greatest extent when no external force is exerted.
Specifically, the titanium film layer is directly plated on the liquid crystal polymer, so that the stress between the titanium dioxide film and the liquid crystal polymer can be effectively buffered, the adhesion between the titanium dioxide film and the liquid crystal polymer is increased, and the whole piezoresistive structure is more reliable.
The first cavity is filled with an insulating liquid (for example, pure water), and the insulating liquid transmits the pressure of the surface of the first cavity to the two interdigital membrane piezoresistors. The insulating liquid may be more sensitive to measuring the pressure difference between the inside and the outside of the first cavity than air. The first cavity can receive external force in 360 degrees in all directions and conduct the external force to the two interdigital film piezoresistors through insulating liquid, so that detection is more sensitive.
Because the first cavity is filled with liquid, the first cavity can conduct pressure within the range of 360 degrees around, all directions can be stressed, conducted and detected, the pressure measurement has no dead angle, and the pressure measurement device is suitable for measuring the blood pressure in the body.
Drawings
FIG. 1 is a schematic diagram of an integrated invasive blood pressure sensor circuit according to an embodiment of the present invention;
FIG. 2 is a schematic front view of an integrated invasive blood pressure sensor according to an embodiment of the present invention;
FIG. 3 is a schematic top view of an integrated invasive blood pressure sensor configuration according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a thin film piezoresistive bridge circuit integrated with an invasive blood pressure sensor according to an embodiment of the present invention;
shown in the figure: 10-a thin film piezoresistive bridge; 11-interdigital film piezoresistance; 12-single strip film piezoresistance; 20-a differential operational amplifier circuit; 30-analog-to-digital conversion circuit; 40-a communication circuit; 50-a state machine; 60-calibrating the digital-to-analog conversion circuit; 71-a substrate of a liquid crystalline polymer; 72-a pressure action chamber; 73-a first encapsulation layer; 74-a first cavity; 75-a second encapsulation layer; 76-a second cavity; 100-Integrated chip.
Detailed Description
The integrated invasive blood pressure sensor according to the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments. Advantages and features of the present invention will become apparent from the following description and from the claims. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.
Furthermore, features from different embodiments of the invention may be combined with each other, unless otherwise indicated. For example, a feature of the second embodiment may be substituted for a corresponding or functionally equivalent or similar feature of the first embodiment, and the resulting embodiments are likewise within the scope of the disclosure or recitation of the present application.
The core idea of the invention is to provide an integrated invasive blood pressure sensor to solve the problem that the bridge output of the existing invasive blood pressure sensor has larger zero offset to cause linear error.
To achieve the above idea, the present invention provides an integrated invasive blood pressure sensor, as shown in fig. 2, comprising: the thin film piezoresistive bridge 10 is configured as a wheatstone balanced bridge and consists of two interdigital thin film piezoresistors 11 which are not connected with each other and two single-strip thin film piezoresistors 12 which are not connected with each other, and when the resistance values of the two interdigital thin film piezoresistors 11 are steady-state values, two voltages output by the thin film piezoresistive bridge 10 are equal; an integrated chip 100 configured to process the voltage output by the thin film piezoresistive bridge 10; liquid crystal polymer, comprising a first encapsulation area and a second encapsulation area, the first encapsulation area carrying the two interdigitated thin film piezoresistors 11, the second encapsulation area carrying the two single strip thin film piezoresistors 12 and the integrated chip 100, wherein: the bottom of the first packaging area is a U-shaped pressure acting cavity 72, the pressure acting cavity 72 is in contact with liquid, and pressure formed by the liquid is transmitted to the interdigital thin film piezoresistor 11 through the pressure acting cavity 72, so that the resistance value of the interdigital thin film piezoresistor 11 is changed.
As shown in fig. 3, in the integrated invasive blood pressure sensor, the interdigital membrane piezoresistance 11 comprises a first piezoresistive element and a second piezoresistive element, wherein: the first piezoresistive assembly and the second piezoresistive assembly are both comb-shaped, and the comb teeth of one of the first piezoresistive assembly and the second piezoresistive assembly are inserted into the teeth of the other one of the first piezoresistive assembly and the second piezoresistive assembly to form an intersecting arrangement. The interdigital thin film piezoresistor 11 and the single strip thin film piezoresistor 12 both comprise a titanium thin film layer and a titanium dioxide thin film which are superposed, and the titanium thin film layer is arranged between the substrate 71 of the liquid crystal polymer and the titanium dioxide thin film; the two interdigital thin film piezoresistors 11 and the two single strip thin film piezoresistors 12 have the same resistance value. Specifically, the titanium film layer is directly plated on the liquid crystal polymer, so that the stress between the titanium dioxide film and the liquid crystal polymer can be effectively buffered, the adhesion between the titanium dioxide film and the liquid crystal polymer is increased, and the whole piezoresistive structure is more reliable.
As shown in fig. 2, the integrated invasive blood pressure sensor further includes: a first encapsulation layer 73 configured to seal the first encapsulation area to form a first cavity 74, the two interdigitated membrane piezoresistors 11 being housed within the first cavity 74; a second packaging layer 75 configured to seal the second packaging region to form a second cavity 76, wherein the two monolithic thin film piezoresistors 12 and the integrated chip 100 are accommodated in the second cavity 76. The first cavity is filled with insulating liquid, and the insulating liquid transmits the pressure of the surface of the first cavity to the two interdigital film piezoresistors. The first cavity is filled with an insulating liquid (for example, pure water), and the insulating liquid transmits the pressure of the surface of the first cavity to the two interdigital membrane piezoresistors. The insulating liquid may be more sensitive to measuring the pressure difference between the inside and the outside of the first cavity than air. The first cavity can receive external force in 360 degrees in all directions and conduct the external force to the two interdigital film piezoresistors through insulating liquid, so that detection is more sensitive.
The integrated chip 100 is integrated on the substrate 71 of the liquid crystal polymer through a CMOS process, as shown in fig. 1, and includes: a differential operational amplifier circuit 20 configured to amplify the voltage generated by the thin film piezoresistive bridge 10 to form an analog amplified signal; an analog-to-digital conversion circuit 30 configured to convert the analog amplified signal into a digital signal after filtering, sample-and-hold, and encoding; a communication circuit 40 configured to transmit the digital signal to a receiving device; a calibration digital-to-analog conversion circuit 60 configured to adjust the voltage output by the differential operational amplifier circuit 20 to zero when the pressure acting chamber 72 does not receive the pressure of the liquid; and the state machine 50 is configured to process the digital signal, judge whether the calibration digital-to-analog conversion circuit 60 is calibrated in place according to the digital signal and control the signal transmission of the communication circuit 40.
In the integrated invasive blood pressure sensor, the communication circuit 40 includes an SPI interface, an I2C interface, a USB interface, a UART interface, an RS-485 interface, a CAN-bus interface, and/or a radio frequency chip. In the integrated invasive blood pressure sensor, the differential operational amplifier circuit 20 is a chopper-stabilized operational amplifier, which can amplify weak signals and has high gain, low temperature drift, high common-mode input range and high voltage rejection ratio. As shown in fig. 4, in the integrated invasive blood pressure sensor, the thin film piezoresistive bridge 10 further includes a constant current source formed by MOS transistors, and the current is kept stable in a wide supply voltage range (3 v to 12 v).
In the integrated invasive blood pressure sensor provided by the invention, through the two interdigital thin film piezoresistors 11 which are not connected with each other, and two single-strip film piezoresistors 12 which are not connected with each other form a film piezoresistor bridge 10, the first packaging region carries two interdigital film piezoresistors 11, the second packaging region carries two single-strip film piezoresistors 12 and the integrated chip 100, the pressure action cavity 72 with the U-shaped bottom of the first packaging area is contacted with liquid, the pressure formed by the liquid is transmitted to the interdigital film piezoresistance 11 through the pressure action cavity 72, therefore, the resistance value of the interdigital thin film piezoresistor 11 is changed, the pressure sensitive resistor is designed by adopting an interdigital structure to form a Wheatstone bridge as shown in figure 4, the matching of the pressure sensitive resistor is more favorably realized in the process of preparation, and the zero point balance of the thin film piezoresistor bridge 10 is ensured to the greatest extent when no external force is applied.
The present invention overcomes the defects of the prior art and provides a design method of a miniature, biocompatible and highly reliable wireless invasive blood pressure sensor, which comprises three parts of cup-shaped Liquid Crystal Polymer (LCP) or cup-shaped LCP, thin film piezoresistance and an integrated chip 100. The cup-shaped LCP is a micro, cup-shaped structure formed using liquid crystal polymers. For convenience of description, the hollow portion of the lower portion of the cup-shaped LCP is referred to as the pressure-acting chamber 72. The thin film piezoresistor comprises four parts: two identical interdigitated film piezoresistors R1 and R2, and two identical elongated film piezoresistors R3 and R4. The resistance values of the four film piezoresistors are the same; two interdigital film piezoresistors R1 and R2 are symmetrically prepared on the upper surface of the cup-shaped LCP pressure cavity; two strip film piezoresistors R3 and R4 are prepared on the upper surface of the cup-shaped LCP; the four membrane piezoresistors form a wheatstone balanced bridge 10 as shown in fig. 4, hereinafter referred to as bridge 10. The interdigital film piezoresistor 11 and the strip film piezoresistor 12 both adopt a titanium film/titanium dioxide film laminated structure with good biocompatibility, wherein the titanium film layer is positioned between the LCP substrate and the titanium dioxide film. The interdigital film resistor on the upper part of the cup-shaped LCP is encapsulated by the LCP and a sealed cavity is formed inside the LCP; the elongated thin film piezoresistive 12 on the top of the cup-shaped LCP and the integrated chip 100 are encapsulated by LCP.
In one embodiment of the present invention, the pressure application chamber 72 is in contact with a subject, such as blood or body fluid. The pressure caused by the blood or body fluid is conducted through the LCP pressure apply chamber 72 to the interdigitated membrane piezoresistors 11 in the upper sealed cavity, the resistance of which changes with pressure. When no external pressure exists, no pressure difference exists between the pressure action cavity 72 and the sealed cavity theoretically, the interdigital film piezoresistance 11 cannot deform, and the output voltage of the bridge 10 balance and differential operational amplifier circuit is zero; when external pressure exists, pressure difference exists between the pressure action cavity 72 and the sealed cavity, the interdigital film piezoresistor 11 deforms, the resistance value of the interdigital film piezoresistor 11 in the sealed cavity changes, the bridge 10 loses balance, and output voltage in direct proportion to the measured pressure is output.
In an embodiment of the present invention, the integrated chip 100 includes five circuit parts, namely, a differential operational amplifier (DAC), a state machine, a calibration DAC (Digital-to-Analog Converter), and a radio frequency circuit, and is integrated on the same silicon chip by using a CMOS process. The differential operational amplifier is a fully differential, high gain operational amplifier circuit, which is used to amplify the weak signal generated by the bridge 10. The ADC is an analog-to-digital conversion circuit with 8 bits or more of precision and low power consumption, and converts an analog signal amplified by differential operational amplification into a digital signal. The state machine controls the radio frequency circuit to wirelessly transmit the output of the ADC in a wireless mode, and controls the output voltage of the calibration DAC to calibrate the voltage on the output node of the bridge 10, so that the output of the sensor device is zero when no external pressure exists. The state machine is connected to the analog-to-digital converter output and to the bridge 10. The bridge 10 is calibrated by the output of the analog-to-digital converter.
As shown in fig. 2, the pressure acting cavity 72 transmits a pressure change signal to the interdigital thin film piezoresistor 11 in the sealed cavity through the LPC, and the wheatstone bridge 10 composed of the interdigital thin film piezoresistor 11 and the strip thin film piezoresistor 12 converts the pressure change into a voltage signal to be output. The resistance values of the 4 thin film piezoresistors are the same. As shown in fig. 3 and 4, the two voltage signals out1 and out2 output by the wheatstone bridge 10 are connected to the input terminals of the differential operational amplifier, and the amplified signals are converted into digital signals by the ADC, and finally transmitted to other receiving devices wirelessly through the radio frequency circuit. In theory, under no load pressure, the bridge 10 is in equilibrium with no output voltage. In fact, however, due to factors such as process, the bridge 10 cannot reach equilibrium under the action of no pressure, and always outputs a voltage signal. In the invention, the output voltage of the differential operational amplifier circuit is zero by adjusting the balance of the bridge 10 through the DAC under the condition of no pressure action, thereby achieving the function of automatic calibration.
In the calibration process, the calibration digital-to-analog conversion circuit outputs an analog voltage, the analog voltage is applied to any one of the connection positions of the two interdigital film piezoresistors and the single-strip film piezoresistor, and the analog voltage is adjusted to enable the two voltages output by the film piezoresistor bridge to be equal.
Compared with the prior art, the invention has the beneficial effects that: the invasive blood pressure sensor device is designed based on the flexible LCP substrate, has miniature volume and can be placed in a tested object. Meanwhile, the radio frequency circuit is used, so that wireless data transmission can be realized. The LPC material adopted by the sensor has good biocompatibility, can transmit microwaves, and has the characteristics of excellent strength, heat resistance, electric insulation, chemical corrosion resistance and the like. In the invention, the pressure sensitive resistor is designed by adopting an interdigital structure, which is more beneficial to realizing resistor matching in the process of preparation, and furthest ensures the balance of the bridge 10 when no external force acts. In the present invention, the calibration DAC and the state machine are used for automatic calibration, and the voltage can be automatically adjusted to balance the bridge 10 without external force, thereby increasing the accuracy and linearity between the pressure input and the signal output of the sensor. The invention adopts differential operational amplifier to amplify the signal, thereby enlarging the measuring range of the pressure signal. Meanwhile, all the devices involved in the invention are integrated on one silicon chip, so that the working reliability, the signal-to-noise ratio and the anti-interference performance of the invasive blood pressure sensor device are improved. The device can collect high-pressure signals and low-pressure signals, has a wide measurement range and wide application, and can be extended to various occasions for measuring pressure in cavities in the process of human and animal operations. The integrated invasive blood pressure sensor provided by the invention has the advantages of high linearity, larger test range and high reliability.
In the invention, a state machine is used for automatic calibration, and the voltage can be automatically adjusted to enable the bridge 10 to reach balance when no external load force exists, so that the linearity between the pressure input and the signal output of the sensor is increased without using a process of compensating a resistor by zero pressure imbalance; the sensor is integrated with the differential signal amplifier, so that the pressure signal measurement range is enlarged, and the signal gain and the signal-to-noise ratio are improved; the invention integrates a digital communication interface, can directly output digital signals and improves the anti-interference performance; all the devices involved in the invention are integrated on a silicon chip, so that the working reliability of the invasive blood pressure sensor is improved.
In summary, the above embodiments have described different configurations integrated with an invasive blood pressure sensor in detail, and it is understood that the present invention includes, but is not limited to, the configurations listed in the above embodiments, and any modifications based on the configurations provided by the above embodiments are within the scope of the present invention. One skilled in the art can take the contents of the above embodiments to take a counter-measure.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. For the system disclosed by the embodiment, the description is relatively simple because the system corresponds to the method disclosed by the embodiment, and the relevant points can be referred to the method part for description.
The above description is only for the purpose of describing the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention, and any variations and modifications made by those skilled in the art based on the above disclosure are within the scope of the appended claims.
Claims (10)
1. An integrated invasive blood pressure sensor, comprising:
the thin film piezoresistive bridge is configured as a Wheatstone balanced bridge and consists of two interdigital thin film piezoresistors which are not connected with each other and two single-strip thin film piezoresistors which are not connected with each other, and when the resistance values of the two interdigital thin film piezoresistors are stable values, two voltages output by the thin film piezoresistive bridge are equal;
an integrated chip configured to process the voltage output by the thin film piezoresistive bridge;
the liquid crystal polymer comprises a first packaging area and a second packaging area, the first packaging area bears two interdigital film piezoresistors, the second packaging area bears two single strip film piezoresistors and the integrated chip, and the liquid crystal polymer comprises:
the bottom of the first packaging area is a U-shaped pressure acting cavity, the pressure acting cavity is in contact with liquid, and pressure formed by the liquid is transmitted to the interdigital thin film piezoresistor through the pressure acting cavity so as to change the resistance value of the interdigital thin film piezoresistor.
2. The integrated invasive blood pressure sensor of claim 1, wherein said interdigitated membrane piezoresistive comprises a first piezoresistive element and a second piezoresistive element, wherein:
the first piezoresistive assembly and the second piezoresistive assembly are both comb-shaped, and the comb teeth of one of the first piezoresistive assembly and the second piezoresistive assembly are inserted into the teeth of the other one of the first piezoresistive assembly and the second piezoresistive assembly to form an intersecting arrangement.
3. The integrated invasive blood pressure sensor according to claim 1, wherein said interdigitated membrane piezoresistors and said monolithic membrane piezoresistors each comprise a stack of a titanium membrane layer and a titanium dioxide membrane,
the titanium thin film layer is disposed between the substrate of the liquid crystal polymer and the titanium dioxide thin film;
the resistance values of the two interdigital film piezoresistors and the two single strip film piezoresistors are consistent.
4. The integrated invasive blood pressure sensor according to claim 1, further comprising:
a first encapsulation layer configured to seal the first encapsulation area to form a first cavity within which the two interdigitated membrane piezoresistors are housed;
and the second packaging layer is configured to seal the second packaging area to form a second cavity, and the two single-strip film piezoresistors and the integrated chip are accommodated in the second cavity.
5. The integrated invasive blood pressure sensor according to claim 4, wherein said first cavity is filled with an insulating fluid, said insulating fluid conducting pressure at the surface of said first cavity to said two interdigitated membrane piezoresistors.
6. The integrated invasive blood pressure sensor according to claim 1, wherein said integrated chip is integrated on said liquid crystal polymer substrate by a CMOS process comprising:
a differential operational amplifier circuit configured to amplify the voltage generated by the thin film piezoresistive bridge to form an analog amplified signal;
the analog-to-digital conversion circuit is configured to convert the analog amplification signal into a digital signal after filtering, sampling and holding and encoding;
a communication circuit configured to transmit the digital signal to a receiving device;
the calibration digital-to-analog conversion circuit is configured to adjust the voltage output by the differential operational amplifier circuit to zero when the pressure action cavity does not receive the pressure of the liquid;
and the state machine is configured to process the digital signal, judge whether the calibration digital-to-analog conversion circuit is calibrated in place according to the digital signal and control the signal transmission of the communication circuit.
7. The integrated invasive blood pressure sensor according to claim 6, wherein said communication circuit comprises an SPI interface, an I2C interface, a USB interface, a UART interface, an RS-485 interface, a CAN-bus interface, and/or a radio frequency chip.
8. The integrated invasive blood pressure sensor according to claim 6, wherein the differential operational amplifier circuit is a chopper-stabilized operational amplifier.
9. The integrated invasive blood pressure sensor according to claim 6, wherein said thin film piezoresistive bridge further comprises a constant current source of MOS transistors.
10. The integrated invasive blood pressure sensor according to claim 6, wherein during calibration, the calibration digital-to-analog conversion circuit outputs an analog voltage, which is applied to any one of the junctions of the two interdigitated membrane piezoresistors and the single strip membrane piezoresistors, and the analog voltage is adjusted so that the two voltages output by the membrane piezoresistive bridge are equal.
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Citations (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201248702Y (en) * | 2008-06-24 | 2009-06-03 | 中国医学科学院生物医学工程研究所 | Flexible pulse detecting probe based on pressure sensing array |
| US20090299216A1 (en) * | 2008-06-02 | 2009-12-03 | Po-Jui Chen | System, apparatus and method for biomedical wireless pressure sensing |
| CN102499661A (en) * | 2011-10-19 | 2012-06-20 | 中颖电子股份有限公司 | Highly integrated electronic sphygmomanometer circuit |
| WO2013044226A2 (en) * | 2011-09-24 | 2013-03-28 | President And Fellows Of Harvard College | Artificial skin and elastic strain sensor |
| CN103070677A (en) * | 2012-12-31 | 2013-05-01 | 王青 | Portable physiological parameter remote measuring device with sampling and medicine perfusion functions |
| CN103110414A (en) * | 2012-12-21 | 2013-05-22 | 西安交通大学 | Full-bridge chip embedded skull pressure sensor |
| CN103180240A (en) * | 2010-10-26 | 2013-06-26 | 美敦力公司 | Wafer-scale package including power source |
| WO2015010064A1 (en) * | 2013-07-18 | 2015-01-22 | Board Of Regents Of The University Of Texas System | Blood pressure analysis system and method |
| CN204562136U (en) * | 2015-04-15 | 2015-08-19 | 沈阳恒德医疗器械研发有限公司 | For the auto-calibrating sensor of electric sphygmomanometer |
| CN105136369A (en) * | 2015-05-28 | 2015-12-09 | 合肥工业大学 | All-flexible resistive touch and pressure perception sensor and manufacturing method thereof |
| CN106859620A (en) * | 2017-01-16 | 2017-06-20 | 清华大学 | A kind of arterial hemangioma rupture pre-warning function system and its method for early warning |
| CN108027674A (en) * | 2016-06-30 | 2018-05-11 | 华为技术有限公司 | A kind of electronic equipment and terminal |
| CN108088909A (en) * | 2017-12-11 | 2018-05-29 | 江西理工大学 | A kind of highly integrated acoustic emission in rock body sensor of high sensitivity |
| CN109890458A (en) * | 2016-10-27 | 2019-06-14 | 心脏起搏器股份公司 | Implantable medical device with pressure sensor |
| CN110074772A (en) * | 2019-05-15 | 2019-08-02 | 长飞光纤光缆股份有限公司 | A kind of pre-calibration intracranial pressure probe |
| CN110269595A (en) * | 2019-07-23 | 2019-09-24 | 上海国民集团健康科技有限公司 | A kind of pulse condition pressure sensor based on liquid-packing |
| CN110720936A (en) * | 2019-09-09 | 2020-01-24 | 浙江省北大信息技术高等研究院 | Implanted pressure sensor and method for measuring internal pressure |
| CN111163688A (en) * | 2017-10-11 | 2020-05-15 | 爱德华兹生命科学公司 | Pressure sensor with integrated level reference |
| CN111735560A (en) * | 2020-07-22 | 2020-10-02 | 钛深科技(深圳)有限公司 | Flexible touch pressure sensor |
-
2020
- 2020-10-29 CN CN202011177844.5A patent/CN112294279B/en active Active
Patent Citations (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20090299216A1 (en) * | 2008-06-02 | 2009-12-03 | Po-Jui Chen | System, apparatus and method for biomedical wireless pressure sensing |
| CN201248702Y (en) * | 2008-06-24 | 2009-06-03 | 中国医学科学院生物医学工程研究所 | Flexible pulse detecting probe based on pressure sensing array |
| CN103180240A (en) * | 2010-10-26 | 2013-06-26 | 美敦力公司 | Wafer-scale package including power source |
| WO2013044226A2 (en) * | 2011-09-24 | 2013-03-28 | President And Fellows Of Harvard College | Artificial skin and elastic strain sensor |
| CN102499661A (en) * | 2011-10-19 | 2012-06-20 | 中颖电子股份有限公司 | Highly integrated electronic sphygmomanometer circuit |
| CN103110414A (en) * | 2012-12-21 | 2013-05-22 | 西安交通大学 | Full-bridge chip embedded skull pressure sensor |
| CN103070677A (en) * | 2012-12-31 | 2013-05-01 | 王青 | Portable physiological parameter remote measuring device with sampling and medicine perfusion functions |
| WO2015010064A1 (en) * | 2013-07-18 | 2015-01-22 | Board Of Regents Of The University Of Texas System | Blood pressure analysis system and method |
| CN204562136U (en) * | 2015-04-15 | 2015-08-19 | 沈阳恒德医疗器械研发有限公司 | For the auto-calibrating sensor of electric sphygmomanometer |
| CN105136369A (en) * | 2015-05-28 | 2015-12-09 | 合肥工业大学 | All-flexible resistive touch and pressure perception sensor and manufacturing method thereof |
| CN108027674A (en) * | 2016-06-30 | 2018-05-11 | 华为技术有限公司 | A kind of electronic equipment and terminal |
| CN109890458A (en) * | 2016-10-27 | 2019-06-14 | 心脏起搏器股份公司 | Implantable medical device with pressure sensor |
| CN106859620A (en) * | 2017-01-16 | 2017-06-20 | 清华大学 | A kind of arterial hemangioma rupture pre-warning function system and its method for early warning |
| CN111163688A (en) * | 2017-10-11 | 2020-05-15 | 爱德华兹生命科学公司 | Pressure sensor with integrated level reference |
| CN108088909A (en) * | 2017-12-11 | 2018-05-29 | 江西理工大学 | A kind of highly integrated acoustic emission in rock body sensor of high sensitivity |
| CN110074772A (en) * | 2019-05-15 | 2019-08-02 | 长飞光纤光缆股份有限公司 | A kind of pre-calibration intracranial pressure probe |
| CN110269595A (en) * | 2019-07-23 | 2019-09-24 | 上海国民集团健康科技有限公司 | A kind of pulse condition pressure sensor based on liquid-packing |
| CN110720936A (en) * | 2019-09-09 | 2020-01-24 | 浙江省北大信息技术高等研究院 | Implanted pressure sensor and method for measuring internal pressure |
| CN111735560A (en) * | 2020-07-22 | 2020-10-02 | 钛深科技(深圳)有限公司 | Flexible touch pressure sensor |
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