An array type pressure measuring device

Abstract

The present invention relates to the field of multi-channel pressure measurement technology, and in particular to an array pressure measurement device, comprising: a gas path system, which is formed by a first alloy substrate with air-conducting holes, a second alloy substrate, a third alloy substrate, and a fourth alloy substrate being sealed and connected in sequence; a circuit system, which is mainly composed of a piezoresistive sensitive chip and a first circuit board; a reference pressure is applied to the front of the piezoresistive sensitive chip, and an external gas pressure is applied to the back to generate a pressure difference; the first circuit board is used to convert the generated pressure difference into an electrical signal proportional to the pressure change and output and process and calculate. The present invention, based on an array piezoresistive sensitive chip and a circuit system, an internal integrated gas path system is conducive to the miniaturization of the entire pressure measurement device assembly.

Description

Technical Field

[0001] The invention relates to the technical field of multi-channel pressure measurement, in particular to an array-type pressure measurement device. Background Art

[0002] The existing multi-channel pressure measurement device installs the piezoresistive MEMS sensor chip in an array form on a circuit board. The circuit board is assembled on an alloy base in a modular manner. On this basis, it is assembled and integrated with the gas valve circuit system. There are problems such as complex material system, complex assembly, and miniaturization. Summary of the invention

[0003] The object of the present invention is to provide an array pressure measurement device to solve the problems raised in the above background technology.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] An array pressure measuring device, comprising:

[0006] The gas circuit system is formed by sealing and connecting a first alloy substrate with gas-conducting holes, a second alloy substrate, a third alloy substrate, and a fourth alloy substrate in sequence;

[0007] The first alloy substrate has air-conducting holes for mounting a piezoresistive sensitive chip;

[0008] The second alloy substrate is used to mount the first alloy substrate;

[0009] The third alloy substrate has air guide holes penetrating the front and back sides and a reference pressure air path for setting a reference pressure, and the conversion of different functional paths can be achieved by moving the third alloy substrate;

[0010] The fourth alloy substrate is used to realize the connection between the internal structure and the external test element or operating device;

[0011] A circuit system, mainly composed of a piezoresistive sensitive chip and a first circuit board;

[0012] Applying a reference pressure on the front side of the piezoresistive sensitive chip and applying an external gas pressure on the back side to generate a pressure difference;

[0013] The first circuit board is used to convert the generated pressure difference into an electrical signal proportional to the pressure change and output and process and calculate it.

[0014] Furthermore, a piezoresistive strip, a passivation layer and a Pad are formed on the front side of the piezoresistive sensing chip, and an open cavity is formed on the back side of the piezoresistive sensing chip;

[0015] The pads include at least one power pad, one ground pad, and two signal pads;

[0016] The aluminum alloy shell is provided with a cavity for accommodating a PCB circuit board and a sealing gasket.

[0017] Furthermore, the first alloy substrate and the second alloy substrate are provided with open cavities on their front sides, wherein: the open cavity of the first alloy substrate is used to install the piezoresistive sensitive chip, and the open cavity of the second alloy substrate is used to install the first alloy substrate.

[0018] Furthermore, a circuit connector corresponding to the open cavity is disposed on the upper end surface of the open cavity on the first alloy substrate, the piezoresistive sensitive chip is electrically connected to the circuit connector through wire bonding, and the circuit connector is vertically disposed and electrically connected to the first circuit chip.

[0019] Furthermore, a boss is provided in the cavity on the front side of the second alloy substrate for accommodating and installing a first circuit board, wherein the first circuit board includes an instrument amplifier circuit, an ADC and an MCU, which are arranged thereon in the form of wire bonding or mounting. The signal generated by the piezoresistive sensitive chip due to the pressure difference is amplified by the instrument amplifier circuit and then enters the ADC module, then enters the MCU processing unit, and finally enters the visual interface for processing and calculation.

[0020] Furthermore, the first alloy substrate can be connected to the second alloy substrate by gluing or screwing.

[0021] Furthermore, the air guide holes of the third alloy substrate are divided into a calibration passage, a test passage and a temperature control passage. The calibration passage and the temperature control passage are combined into a first passage. The third alloy substrate is movable and can switch between the calibration passage or the temperature control passage and the test passage by moving.

[0022] Furthermore, the second alloy substrate is provided with a top cover and a sealing ring to ensure the airtightness of the chamber formed between the two. The chamber has a gas pipeline and an electrical interface to achieve connection with an external reference air pressure source and an external electrical signal.

[0023] Furthermore, the side wall of the third alloy substrate is provided with a sliding guide rail, which is fixed by threads to achieve the positioning and movement of the third alloy substrate in the height direction, and to achieve the conversion between calibration or temperature control and test modes. The outer side of the fourth alloy substrate is respectively provided with stainless steel pipe air ports corresponding to the air guide holes or functional modules, and a hose can also be placed outside the stainless steel pipe to facilitate connection with external test components or operating devices.

[0024] Furthermore, a certain piezoresistive sensitive chip in the first alloy substrate can be replaced by a temperature sensor.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The aluminum alloy substrate and the piezoresistive sensitive chip are directly bonded with packaging glue, and the first circuit board is electrically interconnected with the side of the piezoresistive sensitive chip, which can reduce assembly stress; at the same time, the aluminum alloy substrate is directly connected to the piezoresistive sensitive chip as a heat sink, and the thermodynamic characteristics between the two are simple. Only the temperature sensor assembled on the circuit board can accurately calculate the temperature distribution of the pressure chip under the working state, which is easy to accurately control the thermal stress and help heat dissipation management; in addition, a cooling channel is set inside the aluminum alloy to control the temperature of the array piezoresistive sensitive chip, which is conducive to maintaining long-term stability and comprehensive accuracy and avoiding device performance drift.

[0027] (2) The pressure measurement device has chip-level maintainability. Multiple circuit chips are stacked and integrated, which makes it easy to disassemble and replace the piezoresistive sensitive chip or related circuit system components separately. The gas path system can also be disassembled for cleaning and maintenance.

[0028] (3) The array type piezoresistive sensing chip and circuit system and the internal integrated gas path system are conducive to the miniaturization of the entire pressure measurement device assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the structure of the present invention.

[0030] Figure 2 It is a schematic diagram of the differential pressure piezoresistive sensing chip of the present invention.

[0031] Figure 3 This is a schematic diagram of a piezoresistive sensitive chip for temperature compensation of the present invention.

[0032] Figure 4 It is a front schematic diagram of the first alloy substrate of the present invention.

[0033] Figure 5 It is a side schematic diagram of the first alloy substrate of the present invention.

[0034] Figure 6 It is a schematic diagram of the back side of the first alloy substrate of the present invention.

[0035] Figure 7 It is a front schematic diagram of the second alloy substrate of the present invention.

[0036] Figure 8 It is a side schematic diagram of the second alloy substrate of the present invention.

[0037] Fig. 9 It is a schematic diagram of the back side of the second alloy substrate of the present invention.

[0038] Fig.10 This is a schematic front view of the third alloy substrate of the present invention.

[0039] Fig.11 It is a side schematic diagram of the third alloy substrate of the present invention.

[0040] Fig.12 It is a schematic diagram of the back side of the third alloy substrate of the present invention.

[0041] Fig.13 It is a front schematic diagram of the fourth alloy substrate of the present invention.

[0042] Fig.14 It is a side schematic diagram of the fourth alloy substrate of the present invention.

[0043] Fig.15 It is a schematic diagram of the back side of the fourth alloy substrate of the present invention. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] In the description of the present invention, it should be noted that the terms "upper / lower end", "inner", "outer", "front end", "rear end", "two ends", "one end", "the other end" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0046] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "setting / sleeving", "sleeve connection", "connection", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] See also Figure 1-15 , the present invention provides a technical solution:

[0048] Based on the design and assembly method of array pressure measurement device Figure 1As shown, the pressure measuring device mainly includes a circuit system 100 composed of a piezoresistive sensitive chip 110 and a first circuit board 130, and a gas circuit system 200 composed of a first alloy substrate 210, a second alloy substrate 220, a third alloy substrate 230, a fourth alloy substrate 240, etc.

[0049] The circuit system 100 is composed of a piezoresistive sensing chip 110, a first circuit board 130 and an instrument amplifier circuit 140 thereon, an ADC 150, an MCU 160, etc. The signal generated by the piezoresistive sensing chip 110 due to the pressure difference is amplified by the instrument amplifier circuit and then enters the ADC module, then enters the MCU processing unit, and finally enters the visual interface for processing and calculation. The piezoresistive sensing chip 110 is a silicon substrate, and a piezoresistive strip 111, a passivation layer 112 and a Pad 113 are formed on the front of the piezoresistive sensing chip 110 through processes such as epitaxy, oxidation, diffusion, and sputtering; an open cavity 114 is formed on the back of the piezoresistive sensing chip 110 through an etching process. The Pad 113 includes at least one power pad, one ground pad, and two signal pads.

[0050] The gas circuit system 200 is formed by sealing and connecting a first alloy substrate 210 with gas-conducting holes, a second alloy substrate 220, a third alloy substrate 230, and a fourth alloy substrate 240 in sequence.

[0051] The front side of the first alloy substrate 210 is provided with eight independent open cavities 212 , and eight piezoresistive sensing chips 110 can be installed side by side. There is an air guide hole 211 on the bottom of the open cavity 212 , which is led out from the closed end face of 212 .

[0052] The second alloy substrate 220 has an open cavity on the front side, which can be used to install 8 sets of first alloy substrates 210 side by side. The first alloy substrates 210 can be connected to the second alloy substrate 220 by gluing or screwing, and a total of 64 (8*8 array) piezoresistive sensitive chips 110 can be installed.

[0053] The second alloy substrate 220 has an open cavity on the front side and a boss in the cavity for accommodating and mounting the first circuit board 130 , including the instrument amplifier circuit 140 , ADC 150 , MCU 160 , etc., which are arranged thereon in the form of wire bonding or mounting.

[0054] Circuit connectors 120 corresponding to eight independent open cavities are disposed on the upper end surface of the open cavities on the first alloy substrate 210 . The piezoresistive sensing chip 110 is electrically connected to the circuit connector 120 by wire bonding. The circuit connector 120 is vertically disposed and electrically connected to the first circuit sheet 130 .

[0055] The second alloy substrate 220 is provided with a top cover 250 and a sealing ring to ensure the airtightness of the chamber formed between the two. The chamber has a gas pipeline and an electrical interface to achieve connection with an external reference air pressure source and external electrical signals.

[0056] Each open cavity 212 of the first alloy substrate 210 has an air guide hole 211 in communication with the back cavity of the piezoresistive sensor chip and led out from the lower end surface.

[0057] The second alloy substrate 220 has air-conducting holes 221 running through the front and back sides and a reference pressure gas path 222 for setting a reference pressure; the third alloy substrate 230 has air-conducting holes 231 running through the front and back sides and a reference pressure gas path 232 for setting a reference pressure; wherein the air-conducting holes 233 are divided into a calibration passage 233a, a test passage 233b and a temperature control passage 233c, and the calibration passage 233a and the temperature control passage 233c are combined into a first passage; the fourth alloy substrate 240 has air-conducting holes 241 running through the front and back sides and a reference pressure gas path 242 for setting a reference pressure; the third alloy substrate 230 is mobile and can be switched between the calibration passage 231a or the temperature control passage 231c and the test passage 231b by movement; the air-conducting tubes between the alloy substrates are provided with sealing rings to ensure the sealing of the gas path system.

[0058] The second alloy substrate 220 and the fourth alloy substrate 240 are fixedly connected by screws.

[0059] The side wall of the third alloy substrate 230 is provided with a sliding guide rail 234 which is fixed by a thread 235 to achieve the positioning and movement of the third alloy substrate in the height direction and to achieve the conversion between calibration or temperature control and test modes.

[0060] Stainless steel tube gas ports 245 corresponding to the gas guide holes or functional modules are respectively arranged on the outside of the fourth alloy substrate 240, and a hose 246 can be also sheathed on the stainless steel tube 245 to facilitate connection with external components to be tested or operating devices.

[0061] Preferably, a certain piezoresistive sensitive chip in the first alloy substrate of the device is replaced with a temperature sensitive signal, and the on-site temperature is obtained through processing by the circuit system, and can be set in calibration mode and working mode.

[0062] In the calibration mode, the reference pressure of the chamber formed by the first alloy substrate and the second alloy substrate is set, and the external calibration standard gas source enters from the gas guide hole 243 of the fourth alloy substrate 240, passes through the calibration gas path 233a of the third alloy substrate 230, enters the gas guide hole 221 of the second alloy substrate 220, and finally enters the back cavity 114 of the piezoresistive sensitive chip 110 attached to the upper part of the first alloy substrate 210. The signal generated by the pressure difference sensed by each piezoresistive sensitive chip and the signal generated by the temperature sensitive chip are transmitted to the operational amplifier, after signal amplification, enter the analog-to-digital conversion unit, perform analog-to-digital conversion processing, and finally enter the processor to record the temperature T and the relationship between the input pressure and the generated electrical signal, establish the relationship between the input pressure and the generated electrical signal under different ambient temperature conditions, and store it in the MCU.

[0063] In the working mode, external air enters through the multiple air holes 241 of the fourth alloy substrate 240, passes through the test passage 231 of the third alloy substrate 230, enters the air holes 221 of the second alloy substrate 220, passes through the air holes 211 of the first alloy substrate 210, and finally enters the piezoresistive sensitive chip 110 attached to the upper part of the first alloy substrate 210. Each piezoresistive sensitive chip 110 can be measured separately, and the relationship between the input pressure and the generated electrical signal under different ambient temperature conditions established in the calibration mode is called to achieve fitting compensation.

[0064] In the reference pressure setting mode, external gas enters from the reference pressure gas path 242 of the fourth alloy substrate 240, passes through the reference pressure gas path 232 of the third alloy substrate 230, enters the reference pressure gas path of the second alloy substrate 220, and finally enters the back cavity 114 of the piezoresistive sensitive chip 110 attached to the upper part of the first alloy substrate 210, thereby completing the reference pressure setting of the piezoresistive sensitive chip.

[0065] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An array pressure measurement device, characterized in that: include: The gas circuit system is formed by sealing and connecting a first alloy substrate with gas-conducting holes, a second alloy substrate, a third alloy substrate, and a fourth alloy substrate in sequence; The first alloy substrate has air-conducting holes for mounting a piezoresistive sensitive chip; The second alloy substrate is used to mount the first alloy substrate; The third alloy substrate has air guide holes penetrating the front and back sides and a reference pressure air path for setting a reference pressure, and the conversion of different functional paths can be achieved by moving the third alloy substrate; The fourth alloy substrate is used to realize the connection between the internal structure and the external test element or operating device; A circuit system, mainly composed of a piezoresistive sensitive chip and a first circuit board; Applying a reference pressure on the front side of the piezoresistive sensitive chip and applying an external gas pressure on the back side to generate a pressure difference; The first circuit board is used to convert the pressure difference into an electrical signal proportional to the pressure change, output the electrical signal and process and calculate it; The first alloy substrate and the second alloy substrate are provided with open cavities on their front sides, wherein: the open cavity of the first alloy substrate is used to install the piezoresistive sensing chip, and the open cavity of the second alloy substrate is used to install the first alloy substrate; The first alloy substrate may be connected to the second alloy substrate by gluing or screwing.

2. An array pressure measurement device according to claim 1, characterized in that: A piezoresistive strip, a passivation layer and a pad are formed on the front side of the piezoresistive sensing chip, and an open cavity is formed on the back side of the piezoresistive sensing chip; The Pad includes at least one power pad, one ground pad, and two signal pads.

3. The array pressure measurement device according to claim 1, characterized in that: A circuit connector corresponding to the open cavity is disposed on the upper end surface of the open cavity on the first alloy substrate, the piezoresistive sensitive chip is electrically connected to the circuit connector through wire bonding, and the circuit connector is vertically disposed and electrically connected to the first circuit board.

4. The array pressure measurement device according to claim 1, characterized in that: A boss is provided in the cavity on the front side of the second alloy substrate for accommodating and installing a first circuit board, wherein the first circuit board includes an instrument amplifier circuit, an ADC and an MCU. The instrument amplifier circuit, the ADC and the MCU are arranged on the first circuit board in the form of wire bonding or mounting. The signal generated by the piezoresistive sensitive chip due to the pressure difference is amplified by the instrument amplifier circuit and then enters the ADC module, then enters the MCU processing unit, and finally enters the visual interface for processing and calculation.

5. The array pressure measurement device according to claim 1, characterized in that: The air-conducting holes of the third alloy substrate are divided into a calibration passage, a test passage, and a temperature control passage. The calibration passage and the temperature control passage are combined into a first passage.

6. The array pressure measurement device according to claim 1, characterized in that: The second alloy substrate is provided with a top cover, and the top cover is provided with a sealing ring to ensure the airtightness of the chamber formed between the two. The chamber has a gas pipeline and an electrical interface to achieve connection with an external reference air pressure source and an external electrical signal.

7. The array pressure measurement device according to claim 5, characterized in that: The side wall of the third alloy substrate is provided with a sliding guide rail, which is fixed by threads to realize the positioning and movement of the third alloy substrate and the conversion between calibration or temperature control and test modes. The outer side of the fourth alloy substrate is respectively provided with stainless steel pipe air ports corresponding to the air guide holes or functional modules, and a hose can also be placed outside the stainless steel pipe to facilitate connection with external components to be tested or operating devices.

8. The array pressure measurement device according to claim 1, characterized in that: A certain piezoresistive sensitive chip in the first alloy substrate can be replaced by a temperature sensor.

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