Display Device Pixel Doping for Brightness Uniformity
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Solution Overview
Problem
In display devices, the uniformity of brightness across pixels is compromised due to variations in driving signal magnitudes caused by voltage drops along signal lines, leading to inconsistent light emission.
Innovation Solution
The implementation of a display device design where pixels are strategically doped with varying concentrations of impurities in their semiconductor layers and connected to driving voltage lines with different resistances, ensuring consistent driving voltage delivery regardless of their position relative to the signal transmission lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If driving signals are transferred through long signal lines to pixels far from the driving signal transmission line, then all pixels can be driven, but voltage drops occur causing non-uniform brightness
Solution Approach 1:
The patent applies local quality by doping semiconductor layers with different impurity concentrations in different regions. Pixels closer to the driving signal transmission line have lower impurity concentration, while pixels farther away have higher impurity concentration to compensate for voltage drops, ensuring uniform brightness across the display area.
Solution Approach 2:
The patent changes the electrical parameters of the transistor by varying the impurity concentration in the semiconductor layer based on position. This parameter change adjusts the threshold voltage and conductivity of transistors in different regions, compensating for the voltage drops that occur over long signal line distances.
2Area of stationary object
If driving voltage lines are extended to reach distant pixels, then coverage is improved, but resistance increases causing signal magnitude variations
Solution Approach 1:
The patent implements local quality by creating region-specific doping profiles in the semiconductor layer. Different areas of the display have different impurity concentrations tailored to their distance from the driving signal transmission line, ensuring that signal magnitude remains consistent across the entire covered area despite varying line lengths.
3Ease of manufacture
If uniform impurity concentration is used in all pixels, then manufacturing is simplified, but brightness uniformity deteriorates due to position-dependent voltage drops
Solution Approach 1:
The patent resolves this contradiction by applying local quality through spatially varying impurity concentrations. The doping process is designed to create different concentration profiles in different regions, which compensates for position-dependent voltage drops and achieves brightness uniformity while maintaining manufacturing feasibility through controlled doping variations.
Solution Approach 2:
The patent changes the impurity concentration parameter across different regions of the semiconductor layer. This systematic parameter change allows the device to compensate for electrical losses in different areas, achieving both brightness uniformity and manufacturing practicality through controlled material composition variations.
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 uniform brightness across all pixels by compensating for resistance-induced voltage drops, maintaining consistent driving signal magnitudes and thus achieving uniform light emission.
Implementation Method 1
compensating for resistance-induced voltage drops
Implementation Method 2
pixels are strategically doped with varying concentrations of impurities in their semiconductor layers
Data Source
AI summary
A display device including: a display area including a plurality of pixels; and a peripheral area disposed around the display area to include a driving signal transmission line, each of the pixels may include a transistor, a driving voltage line connected to the transistor and the driving signal transmission line, and a light emitting unit connected to the transistor, the pixels may include a first pixel and a second pixel spaced apart from the driving signal transmission line to have different distances from each other, and a concentration of impurities doped in a semiconductor layer of the transistor of the first pixel may be different from a concentration of impurities doped in a semiconductor layer of the transistor of the second pixel.