Pixel Driving Circuit Segmentation for Luminance Resolution
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Solution Overview
Problem
Current light emitting devices face challenges with color purity, efficiency, and stability under low current driving, particularly in controlling emission time for luminance control, where pulse-width modulation limits luminance resolution.
Innovation Solution
A light emitting device with multiple pixels, each equipped with a first and second pixel driving circuit, where the emission period of the first circuit is shorter than that of the second, allowing for hybrid current and PWM driving schemes to control emission time and luminance, enhancing color purity, efficiency, and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If pulse-width modulation control is used to keep optimum current with changing emission time for luminance control, then luminance control capability is improved, but luminance resolution deteriorates due to limited emission time control resolution
Solution Approach 1:
The pixel driving circuit is segmented into multiple independent sub-circuits, each capable of independent emission time control. This segmentation allows for finer granularity in controlling the emission time, thereby improving luminance resolution while maintaining luminance control capability through the coordinated operation of multiple sub-circuits.
2Loss of energy
If low current driving is used, then power consumption is reduced, but color purity, efficiency, and stability deteriorate
Solution Approach 1:
The system dynamically switches between different driving modes (single circuit driving, dual circuit simultaneous driving, dual circuit sequential driving) based on the required luminance level. At low luminance levels, low current driving is used to save power, while at higher luminance levels, dual circuit driving provides sufficient current to maintain color purity, efficiency, and stability. This dynamic adaptation resolves the contradiction between power consumption and performance reliability.
3Measurement precision
If emission time is extended to improve luminance control, then luminance resolution is improved, but the duration of action increases which may cause instability
Solution Approach 1:
The emission period is segmented into multiple sub-emission periods controlled by different sub-circuits. Each sub-circuit operates for a shorter duration, but the cumulative effect of multiple sub-circuits provides the necessary luminance control resolution. This segmentation allows for extended effective emission control without requiring any single circuit to operate for an excessively long duration, thereby maintaining stability.
Data Source
AI summary
A light emitting device including a plurality of pixels is provided. At least one of the pixels includes a light emitting unit, a first pixel driving circuit and a second pixel driving circuit. The first pixel driving circuit is configured to drive the light emitting unit. The second pixel driving circuit is configured to drive the light emitting unit. An emission period of the first pixel driving circuit is shorter than an emission period of the second pixel driving circuit.