Optical Proximity Sensing With Ambient-Adaptive IR Pulse Control
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Solution Overview
Problem
Conventional proximity sensors require high IR emitter power for optimal performance in bright light conditions, leading to visible screen distortion and increased power consumption in low light conditions, and suffer from shot noise and crosstalk issues.
Innovation Solution
An optical proximity sensor with an integrator circuit that adapts measurement settings based on ambient light intensity, performing ambient light detection and crosstalk compensation in the digital domain to optimize emitter power and reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high IR emitter power is used to meet proximity performance requirements in bright light conditions, then proximity measurement accuracy is improved, but visible screen distortion occurs and power consumption increases in low light conditions
Solution Approach 1:
The patent implements dynamic emitter power adjustment based on ambient light detection. The system continuously monitors ambient light levels and automatically adjusts the IR emitter power accordingly, transitioning from high power in bright conditions to low power in dark conditions. This dynamic adaptation eliminates the need for fixed high power settings, thereby preventing visible screen distortion while maintaining measurement accuracy when needed.
Solution Approach 2:
The patent changes the operational parameters of the IR emitter based on ambient light conditions. By detecting ambient light levels and adjusting emitter power as a variable parameter, the system optimizes performance for each lighting condition. This parameter change approach allows the emitter to operate at high power only when necessary for accurate measurement in bright environments, while consuming minimal power and causing no distortion in low-light conditions.
2Measurement precision
If high IR emitter power is used to meet proximity performance requirements in bright light conditions, then proximity measurement accuracy is improved, but power consumption increases in low light conditions
Solution Approach 1:
The system dynamically adjusts emitter power based on real-time ambient light detection, transitioning from high power consumption modes in bright conditions to low power consumption modes in dark conditions. This dynamic power management ensures the sensor only consumes high power when measurement accuracy is required, thereby reducing overall average power consumption while maintaining performance when needed.
Solution Approach 2:
The patent implements parameter-based power optimization by adjusting emitter power levels according to ambient light conditions. This allows the system to operate at high power only when necessary for accurate measurement in bright environments, while using minimal power in low-light conditions, thus significantly reducing average power consumption across the device's operational profile.
3Device complexity
If a single setting of IR emitter power and receiver is used for all light zones, then device complexity is reduced, but measurement precision deteriorates in low light conditions
Solution Approach 1:
The patent implements dynamic adjustment of emitter power and receiver settings based on ambient light detection. The system automatically adapts these parameters according to lighting conditions, transitioning from fixed single settings to variable multi-setting operation. This dynamic adaptation improves measurement precision in low light conditions while maintaining relatively simple device architecture through automated control.
Solution Approach 2:
The system uses ambient light detection as feedback to automatically adjust emitter power and receiver settings. This feedback mechanism allows the sensor to self-optimize its performance based on environmental conditions without requiring manual intervention or complex user configuration. The feedback-driven adaptation improves measurement precision across different light zones while keeping the overall system design manageable.
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 sensor achieves reduced power consumption, minimized screen distortion, and improved accuracy by dynamically adjusting settings based on ambient light conditions, providing consistent proximity responses across varying light zones.
Implementation Method 1
an infrared light emitter configured to emit AC pulses of infrared light... a light detector configured to detect ambient light DC signals and infrared light AC pulses emitted by the light emitter and reflected from an object to be detected
Implementation Method 2
infrared light AC pulses emitted by the light emitter and reflected from an object to be detected towards the light detector
Implementation Method 3
a light detector configured to detect ambient light DC signals and infrared light AC pulses
Data Source
AI summary
An optical proximity sensor includes an infrared light emitter, a light detector, and an integrator circuit. The infrared light emitter is configured to emit AC pulses of infrared light, and emit no or low levels of infrared light in-between AC pulses. The light detector is configured to detect ambient light DC signals and infrared light AC pulses emitted by the light emitter and reflected from an object to be detected towards the light detector. The integrator circuit performs a proximity measurement employing the light emitter and the light detector. The integrator circuit includes an ambient light measurement circuit configured to perform an ambient light measurement before performing a proximity measurement and to configure measurement settings of the light emitter and/or the light detector and/or the integrator circuit based on the ambient light measurement. The integrator circuit is configured to perform the proximity measurement based on the measurement settings.