Organic Light Emitting Display Using Demultiplexers and Capacitors
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Solution Overview
Problem
Conventional organic light emitting displays require a large number of output lines in their data drivers, increasing production costs and complexity, while also struggling to maintain uniform image brightness.
Innovation Solution
The implementation of a demultiplexer on each output line to distribute data signals to multiple data lines, combined with capacitors that store voltage corresponding to the data signal, reduces the number of output lines needed and ensures uniform brightness by allowing data signals to be supplied simultaneously to pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of data lines is increased to support higher resolution and larger pixel portions, then the display resolution and size are improved, but the number of output lines in the data driver increases, leading to increased production cost and device complexity
Solution Approach 1:
The patent divides the data signal transmission into multiple stages by introducing demultiplexers that sequentially distribute data signals from fewer output lines to multiple data lines. This segmentation allows the data driver to use fewer output lines while still supporting high-resolution displays with many pixels.
Solution Approach 2:
The patent employs capacitors to pre-store data signals during a first period before they are needed for pixel display. This preliminary storage action allows the data driver to transmit data sequentially through fewer output lines, knowing that the signals are already buffered and ready for simultaneous distribution to multiple data lines when needed.
2Device complexity
If the number of output lines is reduced to lower production cost, then the device complexity is decreased, but the uniformity of image brightness deteriorates due to non-simultaneous signal supply to pixels
Solution Approach 1:
The patent uses capacitors to preliminarily store data signals during a first period, ensuring that all necessary data signals are prepared and held ready before the display period begins. This preliminary storage ensures that when the display period arrives, all pixels receive their data signals simultaneously, maintaining uniform image brightness even though the output lines are fewer.
Solution Approach 2:
The patent implements a periodic operation scheme with distinct first period (for charging capacitors) and second period (for displaying images). This periodic action separates the data transmission phase from the display phase, allowing sequential data loading followed by simultaneous pixel activation, thereby maintaining brightness uniformity with reduced output lines.
3Device complexity
If data signals are supplied sequentially to pixels with fewer output lines, then the production cost is reduced, but the time required to supply data signals increases
Solution Approach 1:
The patent performs preliminary data signal charging during a first period using capacitors, so that when the second period (display period) begins, all data signals are already stored and ready for simultaneous distribution. This preliminary action eliminates the time penalty that would otherwise result from sequential data supply during the display period.
Solution Approach 2:
The patent segments the data transmission process into two distinct time segments: a first period for charging capacitors with data signals, and a second period for displaying images using the stored signals. This temporal segmentation allows the system to use fewer output lines without extending the overall data supply time, as the sequential charging occurs in parallel with pixel preparation.
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 decreases the number of data integrated circuits required, lowering production costs and enabling stable, uniformly bright image display by ensuring simultaneous voltage supply to pixels.
Implementation Method 1
a plurality of capacitors formed to have different capacitances according to overlapping areas between the first power source line and the respective data lines, storing voltage corresponding to the data signal
Data Source
AI summary
An organic light emitting display including a demultiplexer on each data line that splits and supplies each data signal to a plurality of data lines, thereby decreasing the number of output lines required and reducing production cost. Further, voltages corresponding to the data signals are sequentially charged in data capacitors, while the charged voltages are supplied to the pixels simultaneously allowing the organic light emitting display to display an image with uniform brightness. Scan periods for supplying the scan signals do not overlap with data periods for supplying the data signals thus yielding a stable image. Also, the capacitance of the data capacitor is set to compensate the voltage drop in the first power source line, thereby displaying an image with uniform brightness.