CN214375033U - Self-checking system and self-checking circuit of equipment based on thermopile - Google Patents
Self-checking system and self-checking circuit of equipment based on thermopile Download PDFInfo
- Publication number
- CN214375033U CN214375033U CN202022272695.2U CN202022272695U CN214375033U CN 214375033 U CN214375033 U CN 214375033U CN 202022272695 U CN202022272695 U CN 202022272695U CN 214375033 U CN214375033 U CN 214375033U
- Authority
- CN
- China
- Prior art keywords
- thermopile
- time constant
- self
- output voltage
- signal processing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Photometry And Measurement Of Optical Pulse Characteristics (AREA)
Abstract
The utility model provides a self-checking system and self-checking circuit of equipment based on thermopile, the self-checking circuit includes: a power control circuit configured to apply a voltage or current excitation through the thermopile and to turn off the excitation of the thermopile when the temperature of the thermopile rises to a preset temperature; a voltage measurement circuit configured to measure a change curve of an output voltage of the thermopile when the power supply control circuit turns off the excitation of the thermopile; a signal processing circuit configured to calculate a temperature-lowering response time of the thermopile based on a variation curve of an output voltage of the thermopile; determining whether the thermopile-based device is acceptable based on the cool-down response time. Compared with the prior art, the utility model discloses when the self-checking mode, provide voltage or electric current excitation and pass through the thermopile so that it heaies up to realize the function of self-checking through the response time of record and the cooling of calculating the thermopile, judge the state of chip.
Description
[ technical field ] A method for producing a semiconductor device
The utility model relates to a MEMS (Micro-Electro-Mechanical System, Micro Electro Mechanical System) device field especially relates to a self-checking System and self-checking circuit of equipment based on thermopile.
[ background of the invention ]
In the production and use processes of the infrared sensor, a defective device is inevitably generated, and the infrared sensor has a self-detection function in order to conveniently and timely find problems and ensure the accuracy of infrared test. In the conventional technical scheme, some heating units special for self-test are required to be additionally arranged to generate excitation, and precious sensitive area is occupied. And some sensors need to be heated in a partitioning mode, and then output absolute values are measured mutually. The method can play a certain detection role, but can not test and distinguish important failure modes such as whether etching is clean or not, whether packaging is air leakage or not, whether gas components are correct or not and the like.
Therefore, a new technical solution is needed to overcome the above problems.
[ Utility model ] content
An object of the utility model is to provide a self-checking system and self-checking circuit of equipment based on thermopile, it need not additionally to set up special unit that generates heat, just can realize the self-checking to equipment based on thermopile.
According to the utility model discloses a first aspect, the utility model provides a self-checking circuit of equipment based on thermopile, it includes: a power control circuit configured to apply a voltage or current excitation through a thermopile to warm up the thermopile when entering a self-test mode, and to turn off the excitation of the thermopile when the temperature of the thermopile rises to a preset temperature; a voltage measurement circuit configured to measure a change curve of an output voltage of the thermopile when the power supply control circuit turns off the excitation of the thermopile; a signal processing circuit configured to calculate a temperature-lowering response time of the thermopile based on a variation curve of an output voltage of the thermopile; it is further configured to determine whether the thermopile-based device is qualified based on the cool-down response time.
According to the utility model discloses a second aspect, the utility model provides a self-checking system of equipment based on thermopile, it includes: a thermopile-based device and a self-test circuit, the self-test circuit comprising: a power control circuit configured to apply a voltage or current excitation through a thermopile to warm up the thermopile when entering a self-test mode, and to turn off the excitation of the thermopile when the temperature of the thermopile rises to a preset temperature; a voltage measurement circuit configured to measure a change curve of an output voltage of the thermopile when the power supply control circuit turns off the excitation of the thermopile; a signal processing circuit configured to calculate a temperature-lowering response time of the thermopile based on a variation curve of an output voltage of the thermopile; it is further configured to determine whether the thermopile-based device is qualified based on the cool-down response time.
Compared with the prior art, the utility model discloses when the self-checking mode, provide voltage or electric current excitation and pass through the thermopile so that it heaies up to realize the function of self-checking through the response time of record and the cooling of calculating the thermopile, judge the state of chip.
[ description of the drawings ]
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without inventive labor. Wherein:
fig. 1 is a schematic circuit diagram of a self-test system for a thermopile-based device in one embodiment of the present invention;
fig. 2 is a schematic flow chart illustrating a self-test method of the self-test circuit shown in fig. 1 according to an embodiment of the present invention;
FIG. 3 is a graph illustrating the self-test output of a typical thermopile measured by the voltage measurement circuit of FIG. 1 in one embodiment of the present invention;
FIG. 4 is a top view of a typical thermopile infrared sensor.
[ detailed description ] embodiments
In order to make the above objects, features and advantages of the present invention more comprehensible, the present invention is described in detail with reference to the accompanying drawings and the detailed description.
Reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with at least one implementation of the invention is included. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Unless otherwise specified, the terms connected, and connected as used herein mean electrically connected, directly or indirectly.
Fig. 1 is a schematic circuit diagram of a self-test system of a thermopile-based device according to an embodiment of the present invention. The thermopile-based device self-test system illustrated in fig. 1 includes a thermopile-based device 110 and a self-test circuit 120.
In the particular embodiment shown in FIG. 1, the thermopile-based device 110 is a thermopile infrared sensor. Fig. 4 is a top view of a typical thermopile infrared sensor. The thermopile infrared sensor shown in fig. 4 includes a support and infrared absorption coating 410 on a base layer (not shown), an absorption region 420 in the middle of the support and infrared absorption coating 410, a plurality of thermocouples T1, T2, T3, T4 at the periphery of the absorption region 420, an infrared absorption optimization layer 430 in the absorption region 420, and a plurality of etching holes 440 distributed in the absorption region 420, the etching holes 440 sequentially penetrating the infrared absorption optimization layer 430, the support and infrared absorption coating 410 to the base layer. Wherein, a plurality of thermocouples T1, T2, T3 and T4 are connected in series in sequence to form a thermopile.
The self-test circuit 120 includes a power control circuit 122, a voltage measurement circuit 124, and a signal processing circuit (or microprocessor) 126.
The power control circuit 122 is coupled to the thermopile infrared sensor 110, the power control circuit 122 configured to: when the self-test mode is entered, preset voltage or current is applied to excite the thermopile, and the temperature of the thermopile can be rapidly increased to the preset temperature due to joule heat generated; when the temperature of the thermopile rises to a preset temperature, the excitation of the thermopile is turned off (or the voltage or current excitation to the thermopile is stopped). For example, a certain controlled voltage is applied to the thermopile by the power control circuit 122, heat is generated due to joule effect, and the temperature of the thermopile rises, wherein
P is the total power applied to the thermopile, V is the voltage applied to the thermopile, and R is the total resistance of the thermopile.
The voltage measurement circuit 124 is configured to: when the temperature of the thermopile rises to a preset temperature and the power control circuit 122 turns off the energization to the thermopile, a variation curve of the output voltage of the thermopile is measured.
The signal processing circuitry 126 is configured to: the time constant τ of the thermopile is calculated based on the variation curve of the output voltage of the thermopile measured by the voltage measurement circuit 124. The time constant tau of the thermopile is: in the change curve of the output voltage of the thermopile, the time required when the output voltage of the thermopile decays from the maximum value to 1/e of the maximum value (or decreases from the maximum value to 63.2% of the maximum value).
The variation curve of the output voltage of the thermopile (or the self-test output curve of the thermopile) generally conforms to the following formula:
wherein, V is the output voltage (or self-test output voltage) at two ends of the thermopile; e is a natural constant having a value of about 2.718281828459045; τ is the time constant of the thermopile; and t is the decay time of the output voltage of the thermopile.
The time constant τ of the thermopile is R × C (3),
wherein R is the thermal resistance of the thermopile, and C is the thermal capacity of the thermopile. Thus, the time constant τ of the thermopile is related to the specific heat capacity, density and volume of the gas and thermopile structure within the thermopile infrared sensor 110.
Fig. 3 is a diagram illustrating a self-test output curve of a typical thermopile according to an embodiment of the present invention, as measured by the voltage measuring circuit 124 shown in fig. 1. In the embodiment shown in fig. 3, the self-test output curves of the thermopile in three cases are shown, which are respectively the self-test output curve of a normal thermopile, the self-test output curve of a thermopile with silicon residue, and the self-test output curve of a thermopile with insufficient air pressure. And the signal processing circuit 126 calculates the time constants τ of the three thermopiles to be 11, 15, and 21 milliseconds, respectively, based on the self-test output curves of the three thermopiles.
In one embodiment, the signal processing circuit 126 calculates the time constant τ of the thermopile based on the self-test output curve of the thermopile by: recording the decay time of the output voltage of the thermopile from the highest point to the lowest point (the output value is equal to or infinitely close to zero), and calculating the time constant tau of the thermopile based on the decay time, wherein the highest point is the output voltage value of the thermopile at the preset temperature, and the lowest point is the output voltage value of the thermopile when the thermopile falls to the ambient temperature (theoretically, the output voltage value is equal to or infinitely close to zero).
It should be noted that the self-test circuit 120 shown in fig. 1 further includes a signal amplifying module (not shown) and an analog-to-digital converting module (not shown). The output end of the voltage measuring circuit 124 is connected to the input end of the signal amplifying module, the output end of the signal amplifying module is connected to the input end of the analog-to-digital conversion module, and the output end of the analog-to-digital conversion module is connected to the input end of the signal processing module 126. The signal amplification module is used for amplifying the change curve of the output voltage of the thermopile measured by the voltage measurement circuit 124; the analog-to-digital conversion module is used for converting the amplified change curve of the output voltage of the thermopile into a digital signal; the signal processing module 126 calculates the time constant τ of the thermopile based on the digital signal.
The signal processing circuitry 126 is further configured to: whether the thermopile infrared sensor 110 is qualified or not is determined based on the time constant τ of the thermopile calculated by the signal processing circuit 126. Specifically, the signal processing circuit 126 compares the calculated time constant τ of the thermopile with a reference time constant, and if the calculated time constant τ is within the reference time constant range, it is determined that the device is qualified; otherwise, judging the device to be unqualified.
The signal processing circuitry 126 is further configured to: and after the device is judged to be unqualified, judging a failure mode according to the calculated difference value between the time constant tau of the thermopile and the reference constant. The failure modes include: incomplete etching, air leakage in packaging, incorrect gas components, incorrect gas pressure, device loss of function and the like.
The signal processing circuitry 126 is further configured to: when the time constant stored in the memory (not identified) in advance is not available, the reference time constant is a preset time constant; when the memory has a pre-stored time constant, the reference time constant is the pre-stored time constant. In one embodiment, the preset time constant may be a measured time constant theoretical value interval.
The signal processing circuitry 126 is further configured to: and after the device is judged to be qualified, storing the calculated time constant tau of the thermopile in the memory to be used as a pre-stored time constant for subsequent self-inspection.
Fig. 2 is a schematic flow chart illustrating a self-test method of the self-test circuit 120 shown in fig. 1 according to an embodiment of the present invention. The self-test method of the self-test circuit shown in fig. 2 includes the following steps.
In step 203, the signal processing circuit 126 calculates the time constant τ of the thermopile based on the variation curve of the output voltage of the thermopile measured by the voltage measuring circuit 124.
In step 204, the signal processing circuit 126 determines whether there is a pre-stored time constant, and if so, the process proceeds to step 205, and if not, the process proceeds to step 206.
And step 210, after the device is judged to be unqualified, judging a failure mode according to the calculated difference value between the time constant tau and the reference constant. The failure modes include: incomplete etching, air leakage in packaging, incorrect gas components, incorrect gas pressure, device loss of function and the like.
It should be particularly noted that steps 206 to 209 can be summarized as follows: the calculated time constant τ of the thermopile is compared with a reference time constant by the signal processing circuit 126 to determine whether the thermopile infrared sensor 110 is acceptable.
The utility model provides a self-checking circuit and self-checking method have following advantage:
1. the utility model is suitable for an all infrared detector. No additional heater, heating unit is needed.
2. The utility model discloses need not heating element and occupy infrared detector's effective area, increased sensitivity.
3. The utility model discloses need not to increase extra circuit for infrared detector's structure.
4. The utility model discloses need not to increase specific level in order to increase the heater, reduced manufacturing cost.
5. In the production process, the utility model discloses can just confirm the state of each chip at the wafer state, for example, whether the sculpture is clean, whether have the detection structure scheduling problem that breaks. That is, the present invention can be used for wafer level testing of devices produced. Therefore, the damaged chip can be picked out in advance, the waste of subsequent packaging materials is reduced, and the packaging process efficiency is improved.
6. In the production process, can pass through the utility model provides a self-checking function confirms whether normally the encapsulation, whether gaseous leaks gas, whether atmospheric pressure is accurate, whether the packaging process has damaged and has surveyed structure etc.. That is, the present invention can be used for package level testing of production devices.
7. The utility model provides a self-checking circuit and self-checking method also are applicable to infrared detection module or other similar infrared detector.
To sum up, the utility model discloses when the self-checking mode, provide voltage or electric current excitation and pass through the thermopile so that it heaies up, realize the function of self-checking through the response time of record and the cooling of calculating the thermopile, judge the state of chip, it not only can improve the coverage of the content of thermopile infrared sensor self-checking, the precision of detection, but also need not additionally to set up special unit that generates heat, has realized the detection to the function of sensor, the integrality of encapsulation.
In the present invention, the terms "connected", "connecting", and the like denote electrical connections, and, unless otherwise specified, may denote direct or indirect electrical connections.
The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiment, but all equivalent modifications or changes made by those skilled in the art according to the present invention should be included in the protection scope of the claims.
Claims (8)
1. A self-test circuit for a thermopile-based device, comprising:
a power control circuit configured to apply a voltage or current excitation through a thermopile to warm up the thermopile when entering a self-test mode, and to turn off the excitation of the thermopile when the temperature of the thermopile rises to a preset temperature;
a voltage measurement circuit configured to measure a change curve of an output voltage of the thermopile when the power supply control circuit turns off the excitation of the thermopile;
a signal processing circuit configured to calculate a temperature-lowering response time of the thermopile based on a variation curve of an output voltage of the thermopile; it is further configured to determine whether the thermopile-based device is qualified based on the cool-down response time.
2. The self-test circuit of a thermopile-based device according to claim 1,
the signal processing circuit is further configured to determine a failure mode of the thermopile-based device based on the cool down response time.
3. The self-test circuit of a thermopile-based device according to claim 1,
the cooling response time of the thermopile is the time constant tau of the thermopile,
the time constant tau of the thermopile is: and in the change curve of the output voltage of the thermopile, the time required for the output voltage of the thermopile to decay from the maximum value to 1/e of the maximum value.
4. The self-test circuit of a thermopile-based device according to claim 3,
"the signal processing circuit is configured to determine whether the thermopile-based device is acceptable based on the time constant τ of the thermopile" includes:
the signal processing circuit compares the time constant tau of the thermopile with a reference time constant, and if the time constant tau is within the reference time constant range, the device is judged to be qualified; if the reference time constant is not within the reference time constant range, the device is judged to be unqualified.
5. The self-test circuit of a thermopile-based device according to claim 4,
the signal processing circuit is further configured to: after the device is judged to be unqualified, judging a failure mode according to the difference value of the time constant tau of the thermopile and the reference time constant;
the failure modes include: incomplete etching, air leakage in packaging, incorrect gas components, incorrect gas pressure and device loss of function.
6. The self-test circuit of a thermopile-based device according to claim 4,
the signal processing circuit is further configured to: when the memory has no pre-stored time constant, the reference time constant is a preset time constant; when the memory has a pre-stored time constant, the reference time constant is the pre-stored time constant,
the signal processing circuit is further configured to: and after the device is judged to be qualified, storing the time constant tau of the thermopile in the memory to serve as a prestored time constant.
7. The self-test circuit of a thermopile-based device according to claim 3,
"the signal processing circuit calculates the time constant τ of the thermopile based on the variation curve of the output voltage of the thermopile" includes:
recording the decay time of the output voltage of the thermopile from the highest point to the lowest point, and calculating the time constant of the thermopile based on the decay time,
the maximum point is an output voltage value when the thermopile is at a preset temperature, and the minimum point is an output voltage value when the thermopile is cooled to the ambient temperature.
8. A self-test system for thermopile-based device, comprising:
a thermopile-based device;
a self-test circuit according to any one of claims 1 to 7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022272695.2U CN214375033U (en) | 2020-10-13 | 2020-10-13 | Self-checking system and self-checking circuit of equipment based on thermopile |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022272695.2U CN214375033U (en) | 2020-10-13 | 2020-10-13 | Self-checking system and self-checking circuit of equipment based on thermopile |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN214375033U true CN214375033U (en) | 2021-10-08 |
Family
ID=77969366
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202022272695.2U Active CN214375033U (en) | 2020-10-13 | 2020-10-13 | Self-checking system and self-checking circuit of equipment based on thermopile |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN214375033U (en) |
-
2020
- 2020-10-13 CN CN202022272695.2U patent/CN214375033U/en active Active
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| TWI621837B (en) | Method and system for measuring heat flux | |
| US20020136261A1 (en) | Heat conductivity measurement method and instrument and method of producing a heat insulating material | |
| US11674833B2 (en) | Detection of contaminations on a sensing surface of a thermal sensor | |
| CN112119290A (en) | Thermopile self-test and/or self-calibration | |
| CN112098765A (en) | Self-checking system, self-checking circuit and self-checking method of equipment based on thermopile | |
| CN214375033U (en) | Self-checking system and self-checking circuit of equipment based on thermopile | |
| US4775831A (en) | In-line determination of presence of liquid phase moisture in sealed IC packages | |
| CN106289537B (en) | Built-in self-test circuit and method for infrared thermopile | |
| CN109781273B (en) | Infrared thermopile temperature sensor and self-testing, self-diagnosis and fault-tolerance method thereof | |
| US7613586B2 (en) | Thermal vacuum gauge | |
| CN113557430A (en) | Sensor device and method for operating a sensor device | |
| US4812801A (en) | Solid state gas pressure sensor | |
| US20210223193A1 (en) | CMOS Compatible Dew Point Sensor Device and Method of Determining a Dew Point | |
| US11747231B2 (en) | Heat-loss pressure microsensors | |
| CN113219317A (en) | Performance parameter testing structure and method for thermosensitive detector | |
| JPH0560716A (en) | Humidity sensor | |
| CN115420769B (en) | Seebeck coefficient test method of infrared thermopile sensor | |
| RU2819824C1 (en) | Self-calibrating temperature sensor on ferrite elements | |
| US10502631B2 (en) | Thermopile test structure and methods employing same | |
| JPH0989672A (en) | Radiation heat sensor | |
| JPH0469531A (en) | Temperature measuring method by radiation thermometer | |
| JP2611680B2 (en) | Temperature measurement method and device | |
| JP2002286560A (en) | Method and device for inspecting temperature sensor | |
| JPH08334545A (en) | Measuring apparatus for semiconductor device | |
| Szucs et al. | Contactless thermal characterization of high temperature test chamber |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |