Ambient Light Sensor Timing for Display Light Interference
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Solution Overview
Problem
Ambient light sensors (ALS) used in conjunction with display devices suffer from inaccurate light intensity readings due to capture of display device photons, leading to positive biases that are difficult to predict and correct, and existing solutions like notch designs or run-time calibration are resource-intensive.
Innovation Solution
Implement a time division duplexing (TDD) timing structure that separates ambient light sensing and display light emission periods, ensuring minimal overlap, allowing for accurate ambient light measurements without significant compute, memory, or power costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the light sensor is positioned close to the light emitters to maintain compact device design, then device size is reduced, but measurement precision deteriorates due to capture of display device photons causing positive biases
Solution Approach 1:
The patent segments the timing operation into distinct phases: a first phase where the light sensor measures ambient light intensity, and a second phase where the light emitters emit display light. This temporal segmentation ensures that the light sensor does not simultaneously detect both ambient light and display light, eliminating the positive bias effect while maintaining the compact positioning of the sensor near the emitters.
Solution Approach 2:
The patent implements periodic action by repeatedly cycling through the measurement phase and emission phase in a time-division duplexing pattern. During each measurement phase, the light sensor periodically captures ambient light intensity; during each emission phase, the light emitters periodically emit display light. This periodic temporal separation allows accurate ambient light measurement while maintaining compact device design.
2Measurement precision
If notch design or run-time calibration is implemented to improve measurement precision, then ambient light reading accuracy is improved, but device complexity increases
Solution Approach 1:
The patent employs dynamic control of the timing operations, where the controller dynamically switches between the measurement phase and emission phase based on a predetermined timing pattern. This dynamic temporal control achieves accurate ambient light measurement without requiring static structural modifications like notches or complex run-time calibration algorithms, thereby reducing device complexity.
Solution Approach 2:
The patent changes the temporal parameters of operation by introducing phase separation between measurement and emission. Instead of modifying structural parameters (like creating notches) or using complex calibration parameter adjustments, the patent achieves measurement precision by changing the timing parameters - specifically, the duration and sequencing of when the sensor operates versus when the emitters operate.
3Productivity
If the light sensor operates continuously to improve productivity, then measurement availability is improved, but use of energy increases due to simultaneous operation with light emitters causing interference
Solution Approach 1:
The patent implements periodic action where the light sensor operates in periodic measurement phases separated by emission phases where the light emitters are active. This periodic operation pattern allows the sensor to repeatedly measure ambient light intensity over time, maintaining measurement availability while consuming less energy than continuous operation would require, since the sensor and emitters are not simultaneously active.
Solution Approach 2:
The patent maintains continuity of useful action by rapidly cycling through measurement and emission phases in a time-division duplexing pattern. This ensures that ambient light measurement functionality remains continuously available over time while minimizing energy consumption, as the sensor only operates during its designated measurement phases rather than continuously alongside the emitters.
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
Improves ambient light intensity readings by reducing the impact of display light interference while maintaining display area and aesthetic appeal, without the need for complex calibration or resource-intensive compensation methods.
Implementation Method 1
a light sensor positioned such that an optical path exists between the light sensor and the one or more light emitters
Data Source
AI summary
A user equipment comprising a display device, a light sensor, and a timing controller configured to provide one or more timing signals to (1) enable the light sensor to sense ambient light during a first portion of a repeated timing pattern and (2) enable one or more light emitters to emit display light during a second portion of the repeated timing pattern, wherein the first portion does not substantially overlap with the second portion, wherein the timing controller is configured to adjust a duty cycle for sensing ambient light within the repeated timing pattern and a duty cycle for emitting display light within the repeated timing pattern, in response to an ambient light intensity measurement based on one or more readings of the light sensor.