Light Sensor Module Polarizing Element Stray Light Blocking
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Solution Overview
Problem
Ambient light sensors in electronic devices, particularly those with OLED displays, face reduced sensitivity due to stray light interference from the display light source, leading to inaccurate brightness sensing results.
Innovation Solution
A light sensor module is designed with a polarizing element sandwiched between the transparent layer and the light sensor, utilizing linear polarizers with differing phase angles to block stray light and allow only ambient light to penetrate, thereby reducing background noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the ambient light sensor is disposed at a deeper location below the narrow rim of the screen to reduce background noise, then the background noise of the sensor is lowered, but the ambient light will be degenerated before reaching the sensor, lowering the sensitivity of the sensor
Solution Approach 1:
A polarizing element is introduced as an intermediary component between the display element and the ambient light sensor. This polarizing element selectively blocks stray light (first phase portion) while allowing ambient light (second phase portion) to pass through to the sensor, thereby reducing background noise without compromising sensitivity
Solution Approach 2:
The polarizing element is strategically positioned only in the specific region where stray light from the display element would interfere with the sensor. This localized application of polarization filtering blocks harmful stray light while preserving the transmission of useful ambient light signals to the sensor
2Measurement precision
If the light sensor is positioned closer to the display element to improve sensitivity, then the sensitivity of the sensor is improved, but stray light from the display will interfere with the sensing results
Solution Approach 1:
The polarizing element serves as a mediator positioned between the display element and the light sensor. It allows the sensor to be placed closer to the display for improved sensitivity while simultaneously blocking stray light through its polarization filtering property
Solution Approach 2:
The harmful stray light component (first phase portion) is extracted and blocked by the polarizing element, separating it from the useful ambient light signal (second phase portion) that reaches the sensor, thereby enabling close positioning without interference
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 configuration enhances the accuracy of ambient brightness sensing by eliminating stray light interference, allowing the light sensor to be positioned closer to the display, thus improving sensitivity and reducing background noise.
Implementation Method 1
The first polarizing element covers the display element, and blocks a first phase portion of the display light source and allows a second phase portion of the display light source to penetrate
Implementation Method 2
The second polarizing element is disposed between the light sensor and the transparent layer and blocks a second phase portion of the display light source
Implementation Method 3
The light sensor includes a light sensing element, which senses the light intensity of the first phase portion of the ambient light source penetrating the second polarizing element
Data Source
AI summary
A module comprises a display element, a first polarizing element, a light sensor, a transparent layer, and a second polarizing element. The display element emits a display light source. The first polarizing element covers the display element, and blocks a first phase portion of the display light source and allows a second phase portion of the display light source to penetrate. The transparent layer covers the first polarizing element. The light sensor is disposed on one side of the display element or the first polarizing element. The second polarizing element is disposed between the light sensor and the transparent layer and blocks a second phase portion of the display light source.