Proximity Sensor Crosstalk Compensation Using Ambient Radiation Coefficients
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Solution Overview
Problem
Proximity sensing devices face inaccuracies due to crosstalk issues, particularly under varying ambient IR light intensities, where a single digital signal value is insufficient for effective compensation, leading to non-zero digital current outputs and erroneous proximity measurements.
Innovation Solution
A proximity sensing device and method that utilize a memory to store multiple ambient radiation level ranges and corresponding coefficients, allowing processing circuitry to select and apply appropriate coefficients or derived values to scale ambient radiation levels, thereby accurately compensating for crosstalk across a range of ambient IR light intensities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single digital signal value is used for crosstalk compensation, then the device complexity is reduced, but the measurement precision deteriorates across varying ambient IR light intensities
Solution Approach 1:
The patent implements dynamic crosstalk compensation by transitioning from a static single-value approach to a dynamic multi-value approach. The system now selects different digital signal values (C1, C2, C3) based on the measured ambient radiation level, allowing the compensation to adapt dynamically to varying lighting conditions and maintain high measurement precision across different environments.
Solution Approach 2:
The patent changes the parameter of compensation values from a fixed single value to multiple values that vary with ambient radiation levels. By storing different digital signal values in memory and selecting appropriate values based on ambient light conditions, the system achieves accurate compensation across a wide range of ambient IR light intensities without significantly increasing device complexity.
2Measurement precision
If multiple coefficients are stored in memory for different ambient radiation levels, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The patent segments the ambient radiation level range into multiple discrete levels (e.g., low, medium, high) and stores corresponding compensation coefficients for each segment. This segmentation allows the system to provide precise compensation for each ambient condition while keeping the overall structure manageable through discrete, organized storage in memory.
Solution Approach 2:
The patent uses copying by storing multiple pre-calculated digital signal values in memory that correspond to different ambient radiation levels. Instead of calculating compensation values in real-time, the system copies pre-computed values from memory, which reduces processing complexity while maintaining high measurement precision across varying conditions.
3Ease of operation
If a single compensation value is used, then the ease of operation is maintained, but the reliability deteriorates under varying ambient radiation conditions
Solution Approach 1:
The patent implements feedback by continuously monitoring the ambient radiation level and using this information to select the appropriate compensation coefficient. The system measures the ambient radiation, compares it against stored reference levels, and adjusts the compensation value accordingly, creating a closed-loop feedback mechanism that maintains high reliability across varying environmental conditions while keeping the operation simple through automated selection.
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
This approach enhances the accuracy of proximity measurements by effectively mitigating crosstalk errors across different ambient radiation levels, even in high-crosstalk applications and strong ambient radiation conditions, providing more precise output than traditional methods.
Implementation Method 1
The proximity sensing device comprises an infrared (IR) LED transmitter and a photodiode configured to detect light reflected from the target
Implementation Method 2
a portion of the light emitted by the IR LED transmitter may be reflected by the surface
Implementation Method 3
a photodiode configured to detect light reflected from the target. The amount of current produced by the photodiode is proportional to the distance between the target and the proximity sensing device
Data Source
AI summary
A proximity sensing device is disclosed comprising: a radiation emitter; a radiation sensor configured to sense a reflected radiation from the radiation emitter; a memory for storing a plurality of ambient radiation level ranges and a plurality of coefficients that map onto the plurality of ambient radiation level ranges; and processing circuitry configured to compensate an output from the radiation sensor for crosstalk by subtracting from the output a measured ambient radiation level scaled by either: a coefficient selected from the plurality of coefficients; or a value derived from the plurality of coefficients. A proximity sensing method and a proximity sensing calibration method are also disclosed.