OLED Display Luminance Control for APL Transitions
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Solution Overview
Problem
OLED display devices experience a rapid decrease in luminance when switching from images with low Average Picture Level (APL) to those with high APL due to the Peak Luminance Control (PLC) curve, causing visual discomfort for users.
Innovation Solution
A display device with a controller that adjusts the output level of images by determining the change in APL and controlling image quality to reduce the luminance change, using a method that involves obtaining the first APL of an image, determining if the second APL is increased, and adjusting the output level to prevent rapid luminance changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a Peak Luminance Control (PLC) curve is used to control luminance, then reliability is improved, but rapid luminance decrease occurs when switching from low APL to high APL images
Solution Approach 1:
The patent applies dynamics by making the PLC curve adjustable rather than fixed. The controller dynamically selects between a first PLC curve for low APL images and a second PLC curve for high APL images, allowing the system to adapt its luminance control behavior based on the current image characteristics. This resolves the contradiction by enabling reliable luminance control while preventing rapid luminance decreases during transitions.
Solution Approach 2:
The patent changes the parameter of PLC curve selection based on APL thresholds. By switching between different PLC curves (first PLC curve for low APL, second PLC curve for high APL), the system modifies its luminance control parameters to match the image content, thereby maintaining reliability while avoiding harmful luminance transitions.
2Reliability
If PLC curve is applied to control luminance, then luminance management is improved, but visual comfort deteriorates due to rapid brightness changes
Solution Approach 1:
The system dynamically adapts the PLC curve selection based on the detected APL of the image. When transitioning from low APL to high APL images, the controller switches to a second PLC curve that prevents rapid luminance decreases, thereby maintaining luminance management reliability while eliminating visual discomfort caused by sudden brightness changes.
Solution Approach 2:
The patent implements feedback by detecting the APL of displayed images and using this information to select the appropriate PLC curve. The controller continuously monitors image characteristics and adjusts the PLC curve selection accordingly, creating a closed-loop system that maintains both reliable luminance management and visual comfort.
3Device complexity
If a fixed PLC curve is used, then device complexity is reduced, but adaptability to different APL images deteriorates
Solution Approach 1:
The patent introduces dynamic PLC curve selection based on detected APL values. The controller automatically chooses between a first PLC curve (for low APL images) and a second PLC curve (for high APL images), providing adaptability to different image types without requiring complex manual configuration or user input.
Solution Approach 2:
The system performs self-service by automatically detecting image APL values and selecting the appropriate PLC curve without user intervention. The controller monitors image characteristics and autonomously adjusts the PLC curve selection, maintaining simplicity while achieving adaptability to different APL conditions.
Data Source
AI summary
In order to prevent a rapid decrease in luminance of a screen as an average picture level (APL) increases, a display device for controlling luminance of an image through a peak luminance control (PLC) curve may comprise a display unit and a controller configured to obtain a first average picture level (APL) of a first image, to determine whether a second APL of a second image is increased compared to the first APL as the first image is switched to the second image, and to control image quality of the second image to reduce an output level of the second image when the second APL is increased compared to the first APL.