Infrared Sensor Chip Self-Diagnosis via Integrated Breakage Detection Wiring
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Solution Overview
Problem
Existing infrared sensors lack an effective self-diagnostic function, particularly when breakage occurs in the bridge of the infrared detection element, leading to inaccurate detection if the output does not decrease.
Innovation Solution
Incorporating breakage detection wiring and heater wiring in the infrared sensor chip, which are connected in series and parallel across the thermopile wiring, allowing for accurate detection of resistance changes and enabling self-diagnosis through Joule heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heater wiring is added to detect wire breakage, then self-diagnostic capability is improved, but device complexity increases
Solution Approach 1:
The patent combines the heater wiring and breakage detection wiring into a single integrated structure. The breakage detection wiring is formed in the same bridge structure as the heater wiring, allowing both heating and diagnostic functions to be achieved through a unified wiring system rather than separate components.
Solution Approach 2:
The heater wiring structure serves multiple functions: it provides heating for the infrared detection element and simultaneously acts as a breakage detection pathway. By making the heater wiring itself detectable for breakage, the system achieves self-diagnosis without requiring entirely separate detection wiring.
2Measurement precision
If breakage detection wiring is integrated into the bridge structure, then detection accuracy is improved, but manufacturing precision requirements increase
Solution Approach 1:
The breakage detection wiring is segmented into multiple sections corresponding to different bridge regions. This segmentation allows the detection system to identify not only whether breakage occurred but also locate the specific bridge section affected, improving detection accuracy while distributing the manufacturing complexity across standardized segments.
Solution Approach 2:
The patent introduces an intermediary measurement approach where resistance changes in the breakage detection wiring serve as a mediator to infer the health status of the infrared detection element. Instead of directly monitoring complex thermal or optical parameters, the system uses electrical resistance as an intermediary indicator that is easier to measure and interpret.
3Reliability
If series connection of heater and breakage detection wiring is used, then self-diagnosis reliability is improved, but energy consumption increases
Solution Approach 1:
The system employs periodic heating cycles rather than continuous heating. The heater wiring is activated in intervals to generate Joule heat for thermal detection, while the breakage detection wiring monitors resistance changes during these periodic cycles. This periodic operation maintains diagnostic reliability while significantly reducing overall energy consumption compared to continuous operation.
Solution Approach 2:
The system utilizes changes in electrical resistance parameters of the breakage detection wiring as indicators of bridge integrity. By monitoring resistance variations caused by Joule heating effects and comparing them against expected values, the system achieves reliable self-diagnosis through parameter analysis rather than requiring increased energy input.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables accurate self-diagnosis of the infrared sensor chip, improving detection accuracy and heat generation efficiency, thereby ensuring reliable operation.
Implementation Method 1
heater wiring wired in an area between the hot junction and the other end of each bridge section and configured to generate Joule heat
Implementation Method 2
Each pixel section 11 includes a temperature sensor and a MOS transistor for extracting an output voltage of the temperature sensor
Data Source
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AI summary
An object of the present disclosure is to provide an infrared sensor which is configured to perform highly accurate self-diagnosis. To achieve the object, the present disclosure has a configuration including: a supporting substrate (13) having a cavity; at least one bridge section (14) extending directly above the cavity (12) and having at least one end (15) supported by the supporting substrate (13) and an other end (19); and a thermopile wiring (9) formed in the at least one bridge section (14) and including hot junctions (17) provided in the at least one bridge section (14) and cold junctions (18) provided directly above the supporting substrate (13), the hot junctions (17) being connected to the cold junctions (18). The at least one bridge section (14) is provided with: at least one breakage detection wiring (20) for detecting breakage of the at least one bridge section (14); and at least one heater wiring (22). The at least one breakage detection wiring (20) is wired along the thermopile wiring (9). The at least one heater wiring (22) is wired such that part of the at least one heater wiring (22) is in an area (21) between the other end (19) of the at least one bridge section (14) and the hot junctions (17).