OLED Reference Voltage Auxiliary Lines Reduce Luminance Differences
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Solution Overview
Problem
Organic light emitting diode displays experience luminance differences due to voltage drops, which degrade image quality, as voltage drops occur in power lines supplying power to pixels, affecting the display device's performance.
Innovation Solution
The implementation of a display device with a reference voltage line and auxiliary lines, connected by conductive and metal lines, which provide a reference voltage to the cathode, increasing the contact area and reducing resistance, thereby mitigating luminance differences caused by voltage drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power lines supply power to pixels in OLED displays, then the display device can operate and emit light, but voltage drops occur in the power lines causing luminance differences and image quality deterioration
Solution Approach 1:
The patent divides the reference voltage line into multiple segments by introducing auxiliary reference voltage lines. Instead of a single continuous reference voltage line, the system uses a main reference voltage line and multiple auxiliary reference voltage lines distributed across the display panel, each segment independently providing reference voltage to reduce the impact of voltage drops in any single segment.
Solution Approach 2:
The patent introduces auxiliary reference voltage lines as intermediary elements between the main reference voltage line and the pixel electrodes. These auxiliary lines act as mediators that distribute reference voltage more evenly across the display panel, reducing the voltage drop effect on pixel operation and improving luminance uniformity.
2Device complexity
If a single reference voltage line is used to provide reference voltage to the cathode, then the structure is simple, but the contact area is limited and resistance is high causing luminance differences
Solution Approach 1:
The reference voltage supply system is segmented into a main reference voltage line and multiple auxiliary reference voltage lines. This segmentation increases the total contact area with the cathode and reduces the resistance of the reference voltage path, thereby improving luminance uniformity without making the overall structure excessively complex.
Solution Approach 2:
The patent extends the reference voltage distribution from a single-line approach to a multi-dimensional network by adding auxiliary reference voltage lines that extend in different directions (first direction and second direction perpendicular to the first). This dimensional expansion increases the contact area and provides multiple pathways for reference voltage distribution.
3Reliability
If the reference voltage line is extended to increase contact area, then luminance uniformity improves, but the space required in the non-display area increases
Solution Approach 1:
The auxiliary reference voltage lines extend in two perpendicular directions (first direction and second direction) from the main reference voltage line, utilizing the two-dimensional space in the non-display area efficiently. This approach increases the contact area and reference voltage distribution effectiveness without requiring excessive linear extension in a single direction.
Solution Approach 2:
The auxiliary reference voltage lines are strategically positioned to extend into specific regions (pixel area and/or driver area) where reference voltage is most needed. This localized approach ensures that the reference voltage is provided where it has the greatest impact on luminance uniformity while minimizing the overall space required in the non-display area.
Data Source
AI summary
Provided is a display device, which includes: a reference voltage line formed along a circular outer line and configured to provide a reference voltage; a first reference voltage auxiliary line electrically connected to the reference voltage line and formed to be parallel with a predetermined interval; and a conductive line forming a contact with the reference voltage line and the first reference voltage auxiliary line and configured to provide the reference voltage to a cathode.