Under-Display Ambient Light Sensing Using Dual Polarizer Sensors
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Solution Overview
Problem
Ambient light sensors beneath displays, such as in smartphones, face inaccuracies due to light emitted by the display being incident upon them, causing confusion between ambient and display light.
Innovation Solution
The use of two sensors with polarizers, where one sensor has a polarizer and the other does not, or has a differently oriented polarizer, allows for differentiation between ambient and display light by generating distinct outputs based on the polarizers' effects on polarized and unpolarized light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ambient light sensor is located beneath the display, then the device structure is simplified and the sensor is protected, but the sensor cannot accurately distinguish ambient light from display light
Solution Approach 1:
The sensing module is divided into multiple sensors with different polarizer configurations. Specifically, some sensors have polarizers while others do not, allowing the system to segment the detection of polarized and unpolarized light components, thereby enabling accurate distinction between ambient and display light.
Solution Approach 2:
Different sensors within the module are given different local properties regarding polarizer presence. This local differentiation allows each sensor to respond differently to polarized versus unpolarized light, creating the capability to distinguish between light sources while maintaining a relatively simple overall structure.
2Measurement precision
If a polarizer is added to the sensing module to distinguish light sources, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The polarizer function is segmented across multiple sensors rather than using a single complex polarizing system. This segmentation achieves accurate light source discrimination while keeping the overall device complexity manageable through modular sensor design.
Solution Approach 2:
The system changes the polarization parameter of light detection by using sensors with and without polarizers. This parameter-based differentiation enables precise measurement of light source characteristics without requiring complex mechanical or optical mechanisms.
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 effectively distinguishes ambient light from display light, improving the accuracy of ambient light sensing and preventing inaccuracies in ambient light measurement.
Implementation Method 1
The ambient light has different polarization characteristics than light emitted by the display. The effect of the polarizer upon light emitted by the display is different from the effect of the polarizer upon ambient light.
Data Source
AI summary
A system comprising a display and an ambient light sensing module, the ambient light sensing module being located beneath the display. The display comprises an array of light emitting diodes and a first polarizer located above the display. The sensing module comprises a first sensor and a second sensor, a second polarizer being located above the second sensor.