Ambient Light Sensing via Blink Detection Off-Period
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Solution Overview
Problem
In bezel-less display configurations, ambient light sensors face challenges in accurately measuring ambient light due to overwhelming light reflections from the display, making it difficult to obtain precise ambient light levels.
Innovation Solution
The implementation of a blink detection technique where a first high-speed photosensor detects incident light during display operation and outputs a measurement signal, which is analyzed by blink detection circuitry to determine the off-period. This information is then used by a second photosensor to measure ambient light only during the off-period, allowing for more accurate light level detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the ambient light sensor is placed under the display, then the device can achieve bezel-less configuration, but the sensor is overwhelmed by display light reflections making accurate ambient light measurement difficult
Solution Approach 1:
The patent utilizes the periodic on-off operation of the display backlight to enable ambient light sensing. The display is operated in a periodic manner where it turns on and off in sync with the frame rate, creating periodic measurement opportunities. During the off-period when the display emits no light, the ambient light sensor can accurately measure ambient light levels without being overwhelmed by display reflections, thus resolving the measurement accuracy problem while maintaining the bezel-less configuration.
2Productivity
If the ambient light sensor operates continuously, then it can capture ambient light changes, but it cannot distinguish ambient light from display light reflections
Solution Approach 1:
The patent employs a feedback mechanism where the ambient light sensor's operation is synchronized with the display's on-off cycles. The sensor operates in response to feedback signals indicating when the display is off, ensuring measurements are taken only during periods when display light is not present. This feedback-based timing coordination enables the sensor to continuously monitor ambient light conditions while maintaining measurement accuracy by excluding display light 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 method enables cleaner and more accurate ambient light measurements by ensuring the ambient light sensor operates during the display's off-period, reducing interference from emitted light and allowing the system to adapt to changes in frame rate without delay.
Implementation Method 1
a first photosensor configured to produce a first measurement signal in response to detecting incident light during operation of the display
Implementation Method 2
a second photosensor configured to detect incident light during the off-period of the blink rate signal
Data Source
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AI summary
Detecting ambient light incident on a display includes: detecting incident light at a first photosensor; producing, at the first photosensor, a first measurement signal in response to detecting the incident light at the first photosensor; transmitting the first measurement signal to blink detection circuitry; deriving, at the blink detection circuitry, a blink rate signal from the first measurement signal, in which the blink rate signal is indicative of both an on-period during which light is emitted by a display and an off-period during which light is not emitted by the display; transmitting the blink rate signal to a second photosensor; and detecting incident light at the second photosensor during the off-period of the blink rate signal.