Ambient Light Sensor Compensation for Display Interference
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Solution Overview
Problem
Ambient light sensors in small electronic devices face space constraints and inaccuracies due to sensitivity to light emitted by the display, affecting brightness measurements.
Innovation Solution
The ambient light sensor's measurements are adjusted by determining brightness values for concentric and overlapping windows in an image frame, converting gamma-corrected pixel values to a linear space, and weighting R, G, and B pixel values to compensate for the displayed content's impact on light detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the ambient light sensor is placed behind or under the display screen to save space, then the device can maintain a compact form factor, but the sensor becomes sensitive to light emitted by the display pixels, leading to inaccurate ambient light measurements
Solution Approach 1:
The patent segments the display content into multiple concentric regions (first region, second region, third region) with different weights applied to each. The first region closest to the sensor gets the highest weight, the second region gets medium weight, and the third region gets the lowest weight. This segmentation allows the system to differentiate between display light from different spatial locations and compensate for its effect on the sensor measurements.
Solution Approach 2:
The patent changes the parameter of regional weighting coefficients to compensate for display light interference. By assigning different weights to different concentric regions of the display content, the system dynamically adjusts the compensation calculation based on the spatial distribution of displayed pixels, thereby correcting the ambient light sensor readings affected by display emissions.
2Area of stationary object
If the ambient light sensor is positioned close to the display to enable compact device design, then space efficiency is improved, but the sensor detects both ambient light and display-emitted light, causing measurement errors
Solution Approach 1:
The patent divides the display area into three concentric regions relative to the sensor position, with the first region being closest to the sensor. This spatial segmentation enables differential weighting where pixels in the first region (which contribute most to sensor interference) are weighted differently than pixels in outer regions, allowing precise compensation for display light while maintaining compact sensor placement.
Solution Approach 2:
The patent applies local quality by assigning different weights to different spatial regions of the display content. The weighting scheme is not uniform but varies locally based on distance from the sensor, with closer regions receiving different weight treatment than farther regions. This local differentiation enables targeted compensation for display light interference at the sensor location.
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 allows for accurate ambient light sensing by accounting for the displayed content's luminance, reducing noise from display light and enabling precise brightness adjustments in small devices.
Implementation Method 1
an ambient light sensor may be used to determine information about light around electronic devices
Implementation Method 2
a self-emissive display such as an organic light emitting diode (OLED) display
Implementation Method 3
the ambient light sensor may be sensitive to light emitted by the pixels (e.g., OLEDs) of the display
Data Source
AI summary
An electronic display includes a display side and an ambient light sensor configured to measure received light received through the display side. The electronic display also includes multiple pixels located between the display side and the ambient light sensor. The multiple pixels are configured to emit display light through the display side.