Organic Light Emitting Display Device with Dummy Pattern Block for Load Balancing
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Solution Overview
Problem
Conventional organic light emitting display devices face challenges in maintaining drive stability due to non-uniformity in threshold voltage and degradation of organic light emitting diodes, which is exacerbated by the use of multiple transistors per pixel leading to uneven scan line loads.
Innovation Solution
The implementation of a dummy pattern block with identical load characteristics to the second signal supply lines, coupled to a scan driver and data driver, ensures balanced parasitic capacitance and load distribution across scan lines, compensating for transistor degradation and threshold voltage variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple transistors are used per pixel to compensate for threshold voltage non-uniformity and OLED degradation, then compensation capability is improved, but scan line load uniformity deteriorates
Solution Approach 1:
The patent applies local quality by configuring different numbers of transistors in different pixel regions. Specifically, pixels in first through fourth rows use four transistors each for threshold voltage compensation, while pixels in fifth through eighth rows use only two transistors. This localized differentiation balances the overall scan line loads while maintaining compensation capability where most needed.
Solution Approach 2:
The display panel is segmented into different row groups (first-fourth rows vs. fifth-eighth rows) with different transistor configurations. This segmentation allows the scan driver to manage loads more uniformly across different scan lines, preventing overload on specific lines while maintaining compensation functionality in critical regions.
2Reliability
If more transistors are used in each pixel for compensation, then threshold voltage non-uniformity compensation is improved, but drive stability deteriorates due to uneven scan line loads
Solution Approach 1:
The patent implements local quality by applying different transistor configurations to different row segments. The first four rows use four-transistor pixels for enhanced threshold voltage compensation, while the fifth through eighth rows use two-transistor pixels. This localized approach ensures compensation where needed while maintaining overall drive stability through balanced load distribution across all scan lines.
3Ease of manufacture
If uniform transistor configuration is used across all pixels, then manufacturing simplicity is improved, but compensation for threshold voltage non-uniformity and OLED degradation is insufficient
Solution Approach 1:
The patent resolves this contradiction by applying local quality principles - different transistor configurations are used in different row regions. The first four rows use four-transistor pixels for superior compensation, while the fifth through eighth rows use two-transistor pixels. This approach maintains reasonable manufacturing complexity while significantly improving compensation capability for threshold voltage non-uniformity and OLED degradation across the display panel.
Data Source
AI summary
An organic light emitting display device capable of ensuring the drive stability. The organic light emitting display includes a plurality of pixels; first signal supply lines respectively coupled to the pixels disposed in at least two horizontal lines; and second signal supply lines being lower in number than the first signal supply lines and respectively coupled to the pixels disposed in the horizontal lines includes a scan driver driving the first and second signal supply lines; a data driver driving data lines disposed in a direction that is crossed to the first and second signal supply lines; and a dummy pattern block providing dummy patterns so that loads of the second signal supply lines are identical to loads of the first signal supply lines.