Under-Display Illuminance Sensor Calibration Without Darkroom Jigs
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Solution Overview
Problem
Illuminance sensors in electronic devices face deviations due to variations in display transmittance and sensor characteristics, leading to inaccuracies in illuminance measurements, and recalibration is costly and inconvenient when components are replaced.
Innovation Solution
A method for calibrating illuminance sensors by measuring illuminance values in a darkroom condition and calculating correction coefficients, and an alternative method using display on-off cycles and color information to adjust for external light interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If calibration is performed in a darkroom condition using a darkroom jig, then measurement precision is improved, but device complexity and ease of operation deteriorate due to requiring special equipment and controlled environment
Solution Approach 1:
The patent extracts the harmful factor (external light) from the measurement environment by performing calibration in a darkroom condition, separating the calibration process from normal operating conditions. This allows the illuminance sensor to measure only display light without external light interference, achieving high precision calibration without requiring complex field calibration equipment.
Solution Approach 2:
The patent performs calibration as a preliminary action during the manufacturing process before the device is deployed. By pre-calibrating the illuminance sensor in a controlled darkroom environment, the system eliminates the need for complex field calibration equipment and procedures, reducing both device complexity and operational difficulty while maintaining high measurement precision.
2Manufacturing precision
If calibration is performed on each combination of displays and illuminance sensors, then manufacturing precision is improved, but productivity deteriorates due to the time-consuming nature of individual calibration
Solution Approach 1:
The patent performs calibration as a preliminary action during the manufacturing process for each display-illuminance sensor combination. By automating the darkroom calibration process and integrating it into the manufacturing flow, the system achieves high manufacturing precision while maintaining acceptable productivity through efficient process design.
Solution Approach 2:
The patent enables the illuminance sensor to perform self-calibration by measuring display light at known luminance levels and automatically calculating correction coefficients. This self-service calibration approach eliminates the need for manual calibration operations, significantly improving productivity while maintaining high manufacturing precision through consistent automated measurement and calculation.
3Ease of operation
If illuminance sensor is disposed under the display, then ease of operation is improved by enabling display luminance adjustment, but measurement precision deteriorates due to inclusion of display light in measurements
Solution Approach 1:
The patent segments the total illuminance measurement into two distinct components: display light and external light. By measuring display light separately (with the display turned on) and external light separately (with the display turned off), the system can subtract display light from the total measurement to obtain precise external light values, maintaining both ease of operation and measurement precision.
Solution Approach 2:
The patent uses periodic action by alternately turning the display on and off to perform different measurements. The illuminance sensor measures display light when the display is on and external light when the display is off, using this periodic measurement pattern to separate and subtract the display light component, achieving precise external light measurement while maintaining the sensor's position under the display for ease of operation.
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 illuminance calibration without darkroom conditions, reducing costs and improving measurement precision while using the device, and maintaining consistent illuminance readings.
Implementation Method 1
An electronic device may measure an illuminance (e.g., an illuminance value of external light) of the environment in which the electronic device is positioned through an illuminance sensor
Implementation Method 2
the light emitted from the display (hereinafter referred to as 'display light')
Data Source
AI summary
An electronic device may include: a display, a light sensor, and at least one processor configured to obtain a first illuminance value based on illuminance data obtained through the light sensor for a first time during which the display is turned on and off, obtain a second illuminance value based on illuminance data obtained through the light sensor for a second time shorter than the first time, while the display is turned on and off, determine a third illuminance value based on the first illuminance value and the second illuminance value, determine a fourth illuminance value based on color information about an image displayed through the display and information related to a luminance of the display, and determine a correction value for correcting an illuminance value obtained through the light sensor based on the third illuminance value and the fourth illuminance value.