OLED Microdisplay Duty Cycle Control for AR Motion Blur
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Solution Overview
Problem
Head-mounted display (HMD) devices experience motion blur when users move their heads while viewing augmented reality images, as current scan-and-hold display technologies do not update images quickly enough to match head motion.
Innovation Solution
The HMD device incorporates a microdisplay with a sensor, such as an accelerometer or gyroscope, to track head movement and adjust the row duty cycle (RDC) and panel duty cycle (PDC) of the LED panel to reduce motion blur, while maintaining constant brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If scan-and-hold display technology is used to display augmented reality images, then power consumption is reduced and simplicity is maintained, but motion blur occurs when the user's head moves during the frame period
Solution Approach 1:
The patent implements dynamic row duty cycle adjustment based on detected head motion. When head movement is detected during a frame period, the system dynamically reduces the row duty cycle for subsequent rows to limit the time LEDs remain illuminated, thereby reducing motion blur. This dynamic adaptation allows the display to respond to user head movements in real-time, resolving the contradiction between maintaining simple scan-and-hold operation and preventing motion blur during head movement.
2Object-affected harmful factors
If the row duty cycle is decreased to reduce motion blur, then motion blur is reduced, but the overall brightness of the display decreases
Solution Approach 1:
The patent employs periodic panel duty cycle adjustments synchronized with the display refresh rate. When motion blur reduction is needed, the system applies panel duty cycle modulation at specific periods within the frame structure, allowing brightness compensation at optimal intervals. This periodic action enables the system to maintain average brightness levels while still implementing row duty cycle reductions to limit motion blur during critical display periods.
Solution Approach 2:
The patent implements coordinated parameter changes by simultaneously adjusting both row duty cycle and panel duty cycle parameters. When head motion is detected, the system reduces the row duty cycle to limit individual row illumination time (reducing motion blur) while concurrently increasing the panel duty cycle to maintain overall display brightness. This dual parameter adjustment resolves the contradiction between reducing motion blur and maintaining display brightness.
3Area of stationary object
If continuous scanning of all rows is performed, then complete image coverage is achieved, but motion blur increases during head rotation
Solution Approach 1:
The patent extracts and selectively processes rows based on detected head motion. When head rotation is detected, the system identifies and applies reduced row duty cycles specifically to rows that would be affected by the motion, while maintaining normal duty cycles for other rows. This selective extraction approach allows the display to maintain complete area coverage while minimizing motion blur only in the affected regions, resolving the contradiction between comprehensive image coverage and motion blur reduction.
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 motion blur and extends the panel's lifetime by dynamically controlling the duty cycles based on head velocity, ensuring a clear and stable augmented reality experience.
Implementation Method 1
Each pixel circuit comprises an organic light emitting diode (OLED)
Implementation Method 2
The sensor can comprise an accelerometer or gyroscope, for example, which is secured to the H M D device and moves with the user's head. The sensor therefore senses an angular velocity of a user's head when the head is rotated.
Data Source
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AI summary
A head-mounted display (HMD) device is provided with reduced motion blur by reducing row duty cycle for an organic light-emitting diode (LED) panel as a function of a detected movement of a user's head. Further, a panel duty cycle of the panel is increased in concert with the decrease in the row duty cycle to maintain a constant brightness. The technique is applicable, e.g., to scenarios in which an augmented reality image is displayed in a specific location in world coordinates. A sensor such as an accelerometer or gyroscope can be used to obtain an angular velocity of a user's head. The angular velocity indicates a number of pixels subtended in a frame period according to an angular resolution of the LED panel. The duty cycles can be set, e.g., once per frame, based on the angular velocity or the number of pixels subtended in a frame period.