OLED AWD Driving with Subframe Erase Phase
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Solution Overview
Problem
Conventional Address While Display (AWD) driving methods for OLEDs suffer from image quality deviations due to errors caused by voltage changes in subpixel luminance based on the previous subframe's state, leading to inaccuracies in luminance determination.
Innovation Solution
The proposed AWD driving method inserts an erase operation into every subframe, ensuring each subframe includes addressing, emission, and erase phases, with a circuit configuration featuring transistors and capacitors to control emission and reset signals, preventing voltage changes based on previous subframe states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If an erase time is inserted into only subordinate subframes in conventional AWD driving method, then the addressing time is reduced, but image quality deviation occurs due to voltage errors from previous subframe states
Solution Approach 1:
The patent divides the frame into multiple subframes with different types (superordinate and subordinate), and applies different erase time insertion strategies to each segment. Superordinate subframes do not insert erase time while subordinate subframes do, creating a segmented approach that optimizes both timing and image quality for different portions of the display cycle.
Solution Approach 2:
The patent applies different driving conditions to different subframes based on their position and characteristics. Superordinate subframes use one driving condition (no erase time) while subordinate subframes use another (with erase time), allowing local optimization of image quality and timing for each subframe type rather than applying a uniform approach.
2Reliability
If erase time is inserted into every subframe, then voltage errors from previous subframe states are prevented, but the overall time for addressing and emission increases
Solution Approach 1:
The patent segments subframes into superordinate and subordinate types, applying erase time insertion selectively rather than universally. This segmentation allows the system to achieve reliability improvements where needed (subordinate subframes) while maintaining better timing performance where possible (superordinate subframes).
Solution Approach 2:
Instead of applying erase time insertion to all subframes (excessive action), the patent applies it only to subordinate subframes (partial action). This partial application is sufficient to prevent the majority of voltage errors while avoiding the time penalty in superordinate subframes, achieving an optimal balance between reliability and timing.
3Illumination intensity
If different weighted times are assigned to subframes in AWD driving method, then luminance control is improved, but voltage instability occurs affecting actual luminance
Solution Approach 1:
The patent inserts erase time into subordinate subframes as a preliminary action before the next superordinate subframe begins. This preliminary erasing of data signals prevents voltage instability from carrying over to subsequent frames, ensuring that the luminance control achieved through different weighted times remains stable across frame transitions.
Solution Approach 2:
The patent converts the potential harm of voltage instability caused by AWD driving into a benefit by strategically inserting erase time only where needed. The erase operation, which consumes time, is transformed into a beneficial voltage stabilization mechanism that protects luminance determination accuracy in subordinate subframes without compromising the overall luminance control scheme.
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 enhances driving accuracy and improves image quality by eliminating error factors that affect luminance determination, thereby improving display quality and reducing image quality deviations.
Implementation Method 1
each pixel section having a light emitting element to driven for light emission in one row is supplied with a data pulse indicative of a first gate voltage of a thin film transistor
Implementation Method 2
By injecting electrons and holes from an electron cathode and a hole anode, respectively, into a light emitting layer, the organic light emitting element is an element that emits light when excitons in which the injected electrons and holes are coupled drop from an excited state to a ground state
Data Source
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AI summary
An Organic Light Emitting Display (OLED) includes: a display panel having subpixels; a scan driver that supplies a scan signal to the display panel; and a data driver that supplies a data signal arranged in a subframe unit in the display panel, wherein the data driver configures the data signal to include an addressing time (Addressing) that transfers a data signal to the subpixel in every subframe, an emission time (Emission) that emits the subpixel, and an erase time (Erase) that erases a data voltage stored at the subpixel, and the Erase occurs as a first node and a second node that control Emission of the subpixel are shortcircuited.