Photosensor Temperature Compensation via Lookup Table Calibration
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Solution Overview
Problem
Temperature drift in light emitting elements, such as VCSELs, affects the accuracy of photosensor devices by reducing the intensity of reflection light with increasing temperature, leading to inaccurate distance determination.
Innovation Solution
A photosensor device with a thermal tracking table unit and temperature sensing unit that calibrates the driving power of the light emitting element based on temperature drift characteristics, using a control module and one-cycle-clock ADC to adjust the light emitting module's power and gain, minimizing temperature-related errors through calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the light emitting element operates at fixed power, then the device structure is simple, but temperature drift occurs causing detection accuracy to deteriorate
Solution Approach 1:
The patent pre-calibrates the relationship between temperature and light output power by storing multiple sets of calibration data (gains) in a lookup table during the manufacturing process. During operation, the system retrieves the appropriate calibration data based on measured temperature, eliminating the need for real-time complex calculations and achieving temperature compensation with minimal processing overhead.
Solution Approach 2:
The system dynamically adjusts the driving power parameters of the light emitting element based on temperature measurements. By changing the power output parameter according to temperature conditions (using pre-stored calibration data), the system compensates for temperature drift effects and maintains consistent detection accuracy across varying temperatures.
2Measurement precision
If temperature compensation calibration is implemented, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
Complex calibration data is pre-computed and stored in a lookup table during manufacturing. The runtime system only needs to perform simple temperature measurement, lookup, and gain application, transforming a potentially complex real-time compensation problem into a simple query and apply operation.
Solution Approach 2:
The patent replaces complex real-time computational compensation mechanisms with a simpler data lookup approach. Instead of calculating compensation factors during operation, the system substitutes mathematical computation with pre-computed data retrieval from a lookup table, reducing processing complexity while maintaining accuracy.
3Reliability
If continuous temperature monitoring and calibration is performed, then temperature drift is reduced, but power consumption increases
Solution Approach 1:
The system performs temperature compensation calibration periodically or at specific intervals rather than continuously. The control unit retrieves calibration data from the lookup table based on temperature changes or time intervals, reducing the frequency of active compensation operations while maintaining effective temperature drift management.
Solution Approach 2:
Calibration data for various temperature conditions is pre-computed and stored during manufacturing. This eliminates the need for continuous real-time calibration calculations, as the system only needs to retrieve pre-prepared data based on current temperature measurements, significantly reducing processing power consumption during operation.
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 calibration mechanism effectively reduces temperature drift, maintaining reflection intensity within an acceptable range and extending the sensing temperature range, with minimal user impact and reduced power consumption.
Implementation Method 1
a temperature sensing unit connected to the one-cycle-clock ADC through a first switch unit, and the temperature sensing unit is configured to sense and convert an ambient temperature to a temperature sensing signal
Implementation Method 2
the driver receives a light control signal from the control module to drive the light emitting element to emit a detection light
Implementation Method 3
a light receiving module configured to receive a reflection light of the detection light from the object and to generate a light sensing signal
Data Source
AI summary
The present invention provides a photosensor device with temperature compensation, which can adjust or calibrate the number, time and power of luminescence of light emitting elements under different ambient temperatures, so that the light signal values received by the photosensor device can be kept consistent or within the error range, there are multiple applications.