Display Pixel Capacitance Layout for Edge Brightness Uniformity
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Solution Overview
Problem
Self-luminous display devices exhibit non-uniform light emission, with the outer edges emitting brighter at low brightness levels compared to the rest of the display area.
Innovation Solution
The display device incorporates pixels with varying capacitor capacitances and control signal timings to achieve uniform light emission across the display region, utilizing transistors and capacitors to manage voltage and current distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a self-luminous display device uses uniform capacitor capacitances across all pixels, then the device structure is simple and easy to manufacture, but the light emission is non-uniform with outer edges emitting brighter at low brightness levels
Solution Approach 1:
The patent applies local quality by differentiating capacitor capacitances based on pixel location. Pixels in the outer edge region (first region) are assigned a first capacitance value, while pixels in the inner region (second region) are assigned a second capacitance value. This local differentiation compensates for the non-uniform light emission characteristics, ensuring that outer edge pixels with higher brightness at low luminance levels use smaller capacitances to reduce charge storage, while inner pixels use larger capacitances to maintain adequate charge storage.
2Illumination intensity
If the display device uses different capacitor capacitances for different pixel regions, then in-plane uniformity of light emission is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent segments the display region into two distinct regions: a first region at the outer edge and a second region in the interior. This segmentation allows for simplified manufacturing by grouping pixels with identical capacitance requirements together, rather than requiring individual customization of each pixel's capacitor. The segmentation strategy reduces device complexity by creating manageable groups with uniform electrical characteristics.
3Device complexity
If control signals are applied with standard timing to all pixels, then the control circuit is simple, but brightness non-uniformity persists across different pixel regions
Solution Approach 1:
The patent introduces dynamic control signal timing where the start timing of control signals varies by pixel region. Pixels in the outer edge region receive control signals with a first timing, while pixels in the inner region receive control signals with a second timing. This dynamic timing adjustment adapts the control strategy to the specific electrical characteristics of each region, compensating for brightness non-uniformity without requiring complex individual pixel control.
Data Source
AI summary
A display device includes a substrate including a display region; and a first pixel arranged in a first region on an outer edge of the display region, and a second pixel arranged in a second region surrounded by the first region. Each of the first pixel and the second pixel includes a first transistor, a second transistor, a first capacitor, a third transistor, and a seventh transistor. A capacitance of a capacitor connected to the gate electrode of the second transistor of the first pixel is different from a capacitance of a capacitor connected to the gate electrode of the second transistor of the second pixel.