Display Pixel Blinking Reduction via Sensor Timing Synchronization
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Solution Overview
Problem
Proximity sensors placed under displays cause interference with the control voltage of display pixels, leading to a visible blinking phenomenon due to IR pulses interacting with the display driving circuit, which degrades the user experience by creating an unwanted white spot on the screen.
Innovation Solution
Synchronizing the emission of IR pulses from the proximity sensor with the display's operation by using a synchronized timing scheme that staggers the activation of display elements and sensing pulses, allowing IR pulses to be emitted only when the pixels are off, such as during display refreshes or pulse width modulation periods, using hardware interrupts and software programmable delays to control the emission of IR pulses based on display control signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the proximity sensor emits IR pulses to detect objects, then the sensor can perform its proximity detection function, but the IR pulses interfere with the display driving circuit causing pixels to blink white
Solution Approach 1:
The proximity sensor emits IR pulses periodically at specific intervals rather than continuously, synchronizing the pulse emission with the display refresh cycle to occur during periods when pixels are not being driven, thereby eliminating the harmful interference while maintaining detection capability
Solution Approach 2:
The system detects the display's timing signals in advance and uses this information to pre-schedule the IR pulse emission times, ensuring pulses are emitted only during safe periods when display elements are off, preventing the blinking phenomenon before it occurs
2Device complexity
If the proximity sensor operates independently with its own pulse timing, then the sensor maintains simple control logic, but the IR pulses coincide with display activation periods causing visible blinking
Solution Approach 1:
The proximity sensor's control logic is merged with the display controller's timing information, allowing the sensor to share the display's timing synchronization signals and coordinate pulse emission with the display refresh cycle, eliminating blinking while maintaining relatively simple overall control
Solution Approach 2:
The display controller acts as an intermediary that provides timing synchronization signals to the proximity sensor, coordinating the sensor's pulse emission with the display's refresh cycle without requiring complex independent control logic in the sensor itself
3Speed
If IR pulses are emitted during display operation, then the proximity sensor can provide real-time detection, but the control voltage to driving circuit is interrupted causing white pixels
Solution Approach 1:
The IR pulses are emitted periodically at intervals that align with the display's natural refresh cycles, specifically during periods when pixels are turned off, allowing real-time proximity detection while maintaining display pixel stability
Solution Approach 2:
The pulse emission timing is dynamically adjusted based on the display's operational state and refresh rate, allowing the sensor to adapt its detection timing to match the display's dynamic behavior and avoid interference with active pixels
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 reduces or eliminates the blinking of pixels, enhancing the display quality and user experience by ensuring IR pulses do not interfere with the control voltage of display elements, thereby minimizing visible disruptions.
Implementation Method 1
Proximity sensors emit a beam of IR light and measure reflected power to detect the proximity of objects
Implementation Method 2
Proximity sensors emit a beam of IR light and measure reflected power to detect the proximity of objects
Data Source
AI summary
Reducing blinking pixels in a display includes detecting a first timing of activation of one or more emissive elements of the display, detecting a second timing of sensing pulses from a sensor arranged to detect radiation transmitted through the display, determining, based on the first timing and the second timing, a synchronized timing that staggers the activation of the one or more emissive elements of the display and the sensing pulses from the sensor, and dynamically altering, based on the determined synchronized timing, a subsequent timing of the sensing pulses from the sensor to reduce blinking of at least some of the pixels compared to blinking associated with the synchronized timing.