OLED Display Dual Reference Voltage Lines
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Solution Overview
Problem
Organic light emitting display devices experience brightness deviation (luminance deviation) due to variations in reference voltage applied to adjacent lines, leading to inconsistent brightness across pixels.
Innovation Solution
The implementation of a dual reference voltage system where odd-numbered and even-numbered pixel lines are connected to separate reference voltage lines, ensuring each pixel receives a consistent voltage level, thereby minimizing IR deviation and luminance differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single reference voltage line is used for all pixels, then the device complexity is reduced, but brightness deviation occurs between adjacent lines due to IR deviation
Solution Approach 1:
The patent divides the pixel array into multiple groups based on row parity (odd and even rows), and assigns separate reference voltage lines to each group. This segmentation approach reduces IR deviation by limiting the current path length for each reference voltage line, thereby improving brightness uniformity without significantly increasing overall device complexity.
Solution Approach 2:
Different regions of the display (odd rows and even rows) are provided with different reference voltage lines tailored to their specific current requirements. This local differentiation ensures that each region receives appropriate reference voltage, improving local brightness uniformity while maintaining overall system functionality.
2Adaptability or versatility
If reference voltage is varied for different lines, then brightness can be adjusted for each line, but brightness deviation occurs between lines
Solution Approach 1:
The patent ensures that all pixels receive the same reference voltage level by providing separate reference voltage lines for odd and even rows that both output the same voltage. This equipotential approach maintains brightness consistency across all lines while preserving the ability to adjust brightness through data voltage control.
3Productivity
If overlap driving is implemented for k-th and (k+1)-th pixels, then driving efficiency is improved, but complexity of gate driver control increases
Solution Approach 1:
The gate driver implements periodic scan signals that sequentially activate pixels in a systematic pattern. The overlap driving mechanism uses periodic sense signals to read data from pixels after they have been programmed, enabling efficient sequential operation without requiring complex arbitrary control logic.
Data Source
AI summary
Various embodiments provide is an organic light emitting display device including a first pixel having a first organic light emitting diode (OLED) and a first driving transistor and a second pixel having a second OLED and a second driving transistor. The first pixel and the second pixel are electrically connected to a first data line. A source electrode of the first driving transistor is electrically connected to a first reference voltage line, and a source electrode of the second driving transistor is electrically connected to a second reference voltage line.