Alternating Signal Line Selection Order for OLED Display Uniformity
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Solution Overview
Problem
Display unevenness occurs due to potential differences in electric potential across signal lines in organic electroluminescence (EL) display devices, leading to reduced image quality and luminance differences between columns.
Innovation Solution
The arrangement of selection circuits and display blocks is modified such that the order of signal line selection for pixels in each row differs between frame periods or horizontal scan periods, ensuring that the time image signals are held by signal lines is more uniform across multiple periods, thereby reducing luminance differences and display unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If signal lines are divided into blocks for each selection circuit to reduce output circuits, then the number of output circuits from driving circuit is decreased, but display unevenness occurs due to electric potential differences across signal lines
Solution Approach 1:
The patent applies periodic action by alternating the signal writing direction between odd and even frame periods. In odd frame periods, signals are written from the first end to the second end of signal lines, while in even frame periods, signals are written from the second end to the first end. This periodic reversal compensates for electric potential differences caused by leakage currents, reducing display unevenness while maintaining the blocked selection circuit structure
Solution Approach 2:
The patent introduces dynamic switching of signal writing direction based on frame period parity. The selection circuits dynamically change their signal output sequence - odd-numbered selection circuits write signals in one direction during odd frames and reverse direction during even frames. This dynamic adaptation eliminates static electric potential differences without increasing circuit complexity
2Ease of operation
If signal is supplied in the same order to all signal lines connected to selection circuit, then circuit operation is simplified, but electric potential difference for signal occurs due to leakage current and holding time variation
Solution Approach 1:
The patent implements periodic reversal of signal writing direction. During odd frame periods, signals are supplied from the first end to the second end of signal lines. During even frame periods, the direction is reversed from the second end to the first end. This periodic action ensures that all signal lines have equal average holding times, eliminating electric potential differences while keeping the selection circuit operation simple and systematic
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 minimizes display unevenness and maintains consistent image quality by averaging the time image signals are held across multiple periods, reducing luminance differences between columns and enhancing overall image quality.
Implementation Method 1
a light emitting element that uses organic electroluminescence (EL) induced by an organic material that emits light as a light emitting layer
Data Source
AI summary
A display device in which selection circuits and display blocks are arranged is provided. Each of display blocks comprises signal lines extending in a column direction and pixels arranged in a matrix pattern. Pixels each comprise a light emitting element. Each of selection circuits switches a signal line to which to supply an image signal among signal lines such that the image signal is written to each pixel aligned in a row direction among pixels. In one frame period, an order in which signal lines corresponding to respective pixels arranged in a first row among the pixels aligned in the row direction are selected, and an order in which signal lines corresponding to respective pixels arranged in a second row different to the first row among the pixels aligned in the row direction are selected are different to each other.