Proximity Sensing Calibration for Ambient Light and Crosstalk
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Solution Overview
Problem
Proximity sensing devices face interference from ambient light and crosstalk due to reflections from cover glass, protective films, and dirt, which affect measurement accuracy and require high accuracy and fast response in modern electronic devices.
Innovation Solution
A proximity sensing device with a control module, light-emitting and receiving modules, analog front-end, and digital converters, utilizing a one cycle clock base analog-to-digital converter and calibration digital-to-analog converters to perform coarse and fine crosstalk calibration, and ambient light calibration, allowing for quick elimination of interference and improved accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional proximity sensing is used, then basic proximity detection is achieved, but measurement accuracy deteriorates due to ambient light interference and crosstalk from reflections
Solution Approach 1:
The patent segments the light detection process into multiple wavelength channels (e.g., first wavelength for object reflection, second wavelength for crosstalk detection, third wavelength for ambient light detection). By separating these detection functions into distinct wavelength bands, the system can independently measure and subtract crosstalk and ambient light effects from the primary proximity signal, thereby improving measurement accuracy without being affected by these interference sources.
Solution Approach 2:
The patent introduces intermediary wavelength channels as mediators to detect and characterize interference sources. Specifically, a second wavelength channel detects crosstalk from cover glass reflections, and a third wavelength channel detects ambient light levels. These intermediary measurements serve as reference signals that enable the system to compensate for interference in the primary proximity detection channel, effectively using mediators to isolate and eliminate harmful factors.
2Measurement precision
If multiple calibration processes are implemented to eliminate interference, then measurement accuracy improves, but device complexity increases
Solution Approach 1:
The patent implements a multi-functional calibration system where a single set of wavelength channels and detection circuits serves multiple purposes. The same photodetector array and signal processing unit used for primary proximity detection also perform crosstalk calibration and ambient light calibration by analyzing light at different wavelengths. This universal approach allows the system to achieve high measurement accuracy through multiple calibration processes without proportionally increasing device complexity, as the hardware infrastructure is shared across all calibration functions.
3Speed
If fast response is required for new generation electronic products, then response time decreases, but calibration accuracy may be compromised
Solution Approach 1:
The patent employs periodic action by implementing calibration processes that occur at specific intervals or triggers rather than continuously. The system can perform rapid wavelength-based measurements and use pre-established calibration data to maintain accuracy during normal operation, with full calibration cycles executed periodically or when triggered by specific conditions (e.g., device wake-up, environmental changes). This periodic approach enables fast response during normal proximity detection while maintaining calibration accuracy through scheduled updates.
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 rapid and accurate elimination of interference sources, ensuring high accuracy and fast response in proximity sensing, particularly effective in eliminating ambient light and crosstalk effects, enhancing system operation.
Implementation Method 1
The LED emits a detection light on an object approaching the device. The PD receives the detecting light reflected by the object
Implementation Method 2
The PD receives the detecting light reflected by the object and converts into an electrical signal
Data Source
AI summary
The present invention provides a proximity sensing device, which comprises an ambient light calibration digital-to-analog converter and at least one crosstalk calibration digital-to-analog converters. The proximity sensing device is able to quickly generate calibration parameters for the interference caused by the ambient list and crosstalk caused by different reflection, to calibrate the sensed signals to avoid wrong judgments.