Ambient Light Sensor Ink Interference Compensation
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Solution Overview
Problem
Ambient light sensors installed beneath panel glass coated with ink face distortion in their response spectrum, leading to reduced correlation between sensor readings and human eye perceived illuminance, which complicates estimation accuracy for illuminance.
Innovation Solution
The implementation of an optical filter that adjusts the light sensing characteristics of the light sensing device to include a valid wavelength range of 590 nm to 630 nm and an invalid range above 700 nm, effectively minimizing the influence of ink on ambient light sensing and enhancing estimation accuracy for illuminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the light sensor is disposed below the panel glass coated with ink to achieve full screen without holes, then the aesthetic appearance is improved, but the response spectrum of the light sensor is distorted leading to reduced measurement precision
Solution Approach 1:
An optical filter is introduced as an intermediary component between the ink layer and the light sensing device. This optical filter compensates for the spectral distortion caused by the ink, allowing the light sensor to maintain measurement precision while remaining hidden beneath the ink-coated glass for aesthetic purposes
Solution Approach 2:
The optical filter is designed with specific spectral transmission characteristics that modify the wavelength distribution of light reaching the sensor. By adjusting the filter's optical parameters, the system compensates for the ink-induced spectral distortion and restores accurate illuminance measurement across different lighting conditions
2Measurement precision
If individual calibration is performed to improve illuminance estimation accuracy, then measurement precision is improved for specific conditions, but device complexity and manufacturing difficulty increase due to varying ink types and environmental light sources
Solution Approach 1:
The optical filter is designed with universal spectral characteristics that compensate for ink-induced distortion across multiple ink types and environmental lighting conditions. This single filter design provides broad-spectrum compensation without requiring individual calibration for different scenarios, reducing manufacturing complexity while maintaining measurement accuracy
3Measurement precision
If excessive components are added to enhance sensing accuracy, then measurement precision is improved, but cost increases making it less applicable in the market
Solution Approach 1:
The optical filter is implemented as a thin-film coating or simple optical element that can be manufactured at low cost using existing semiconductor fabrication processes. This approach provides effective spectral compensation without requiring expensive additional components, maintaining cost-effectiveness for mass market applications
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 solution significantly increases the estimation accuracy for illuminance, controlling errors within ±10% across various ink conditions and ambient light sources, while maintaining cost-effectiveness and broad applicability.
Implementation Method 1
The optical filter is disposed to make a valid light-sensing wavelength range of the light sensing device include 590 nm ̃630 nm and an invalid light-sensing wavelength range of the light sensing device be above 700 nm
Implementation Method 2
a light sensing device sensing the light passing through an optical filter and giving an optical signal value
Data Source
AI summary
The present invention provides an ambient light sensing method and an ambient light sensor. The ambient light sensing method comprises a light sensing device sensing the light passing through an optical filter and giving an optical signal value, and an operational unit receiving the optical signal value and calculating an ambient light illuminance value according to the optical signal value. Accordingly, the ambient light sensing method and the ambient light sensor according to the present invention can give the ambient light illuminance value with more accuracy and ensure low influence of opaque ink on ambient light sensing.