OLED Luminance Adjustment via Compensation Zones
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Solution Overview
Problem
Large-sized OLED panels experience uneven luminance due to varying IR drops across the panel, leading to reduced aperture ratio and luminance uniformity, which conventional pixel driver circuits fail to adequately address.
Innovation Solution
The method involves dividing the display zone into compensation zones, adjusting the current in OLED sub-pixels by modifying the width-to-length ratio of the channel and contact resistance in driving thin-film transistors to equalize luminance across zones, thereby increasing the aperture ratio and achieving uniform luminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional pixel driver circuits (2T1C or 7T1C) are used to address luminance uniformity, then luminance uniformity is improved, but aperture ratio is lowered due to requiring more thin-film transistors
Solution Approach 1:
The display panel is divided into multiple compensation zones (first compensation zone, second compensation zone, etc.) along the row direction, with each zone having its own compensation capacitor. This segmentation allows independent luminance compensation for different regions without requiring additional transistors in each pixel, thus improving luminance uniformity while maintaining aperture ratio.
Solution Approach 2:
Different compensation capacitors are configured for different compensation zones to provide localized luminance compensation. The compensation capacitors are connected to specific scanning signal lines and emission control signal lines, enabling region-specific current adjustment to correct IR drop variations in different areas of the display panel.
2Stability of the object's composition
If the cathode resistance is reduced to improve luminance uniformity, then luminance uniformity is improved, but manufacturing complexity increases
Solution Approach 1:
Compensation capacitors are introduced as intermediary elements between the driving thin-film transistors and the OLEDs. These capacitors store and regulate current in each compensation zone, mediating the effect of cathode resistance variations and enabling luminance uniformity without requiring changes to the cathode structure or material.
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 ensures consistent luminance across the OLED panel, enhancing both aperture ratio and luminance uniformity by adjusting currents in sub-pixels within compensation zones.
Implementation Method 1
adjusting the current in an organic light-emitting diode (OLED) for a sub-pixel by adjusting at least one of the width-to-length ratio of a channel and a contact resistance in a driving thin-film transistor for the sub-pixel
Implementation Method 2
obtaining an adjusted current by adjusting a current in an organic light-emitting diode (OLED) for a sub-pixel
Data Source
AI summary
A method and a device for luminance adjustment for a display panel are provided. The method includes: dividing a display zone into a plurality of compensation zones; acquiring a difference between an initial luminance value and a pre-determined reference luminance value in each of the plurality of compensation zones; obtaining an adjusted current by adjusting a current in an organic light-emitting diode (OLED) for a sub-pixel in a compensation zone corresponding thereto according to the difference for the compensation zone; and obtaining a target luminance value by compensating the initial luminance value for the compensation zone corresponding thereto according to the adjusted current.