Active-Matrix Display Write Scanner Dual-Pulse Correction
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Solution Overview
Problem
Active-matrix planar light-emitting display devices using organic electroluminescent elements face variations in threshold voltage and mobility of drive transistors and organic EL devices, leading to non-uniform luminance, and existing correction methods increase power consumption due to high-speed gate pulses.
Innovation Solution
A display device with a pixel array section and a drive section, including sampling and drive transistors, a storage capacitor, and a write scanner that uses two pulses in each horizontal scanning period to perform threshold-voltage and mobility correcting operations, reducing power consumption by minimizing the effective operating frequency and using a pulse power supply efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sampling transistors are driven with high-speed gate pulses to perform correction operations, then correction precision is improved, but power consumption increases
Solution Approach 1:
The patent applies periodic action by using two distinct pulses (first pulse and second pulse) within each horizontal scanning period to drive the sampling transistor. The first pulse performs threshold voltage correction while the second pulse performs mobility correction, enabling precise correction operations through periodic gating rather than continuous high-speed pulsing. This reduces the effective operating frequency and power consumption while maintaining correction precision.
2Manufacturing precision
If multiple correction operations are performed in each horizontal scanning period, then luminance uniformity is improved, but the effective operating frequency increases
Solution Approach 1:
The patent segments the correction operations into two distinct phases within each horizontal scanning period: threshold voltage correction (first pulse) and mobility correction (second pulse). By dividing the correction function into separate operational segments with dedicated timing, the system achieves comprehensive correction for luminance uniformity without requiring a single high-frequency operation, thus managing the effective operating frequency more efficiently.
3Speed
If the pulse power supply operates at high frequency to support correction operations, then correction speed is improved, but the load on the pulse power supply increases
Solution Approach 1:
The pulse power supply operates periodically at a reduced effective frequency by providing pulses only during specific phases of the horizontal scanning period (first pulse for threshold correction, second pulse for mobility correction). This periodic operation mode maintains correction speed by ensuring corrections occur within the required timeframe while significantly reducing the average load on the pulse power supply compared to continuous high-frequency operation.
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
The solution enables accurate correction operations with reduced power consumption, maintaining uniform luminance across the display while minimizing the load on the pulse power supply and modules, thereby enhancing the display's efficiency and image quality.
Implementation Method 1
organic EL devices are devices using the phenomenon that an organic thin film emits light when an electric field is applied thereto
Data Source
AI summary
A display device includes a drive section and a pixel array section including power lines, scanning lines, signal lines, and pixels in a matrix. Each pixel includes a sampling transistor, a drive transistor, a light-emitting element, and a storage capacitor. The drive section includes a write scanner supplying a control signal to one scanning line at a time, and a signal selector supplying a drive signal to each signal line. The sampling transistor applies the drive signal to the drive transistor. The drive transistor supplies a drive current based on the drive signal to the light-emitting element. The write scanner includes output buffers, each outputting a control signal including two pulses to a corresponding scanning line. Each output buffer includes first and second output sections, the first section outputting one pulse and the second section extracting a pulse from a pulse power supply and outputting the extracted pulse.