Data Driver Voltage Selection for High-PPI Luminance Accuracy
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Solution Overview
Problem
As pixel density increases in display devices, the dynamic range of data voltage decreases, leading to reduced luminance accuracy due to variations in data voltage, necessitating a solution to expand the dynamic range.
Innovation Solution
A data driver that selectively outputs a reference voltage or data voltage through a source channel, utilizing a pixel structure with capacitors and transistors to maintain consistent offset voltages, thereby minimizing luminance differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixel density is increased to achieve high PPI display, then display resolution is improved, but dynamic range of data voltage is reduced and luminance accuracy deteriorates
Solution Approach 1:
The patent segments the voltage control function by introducing a dual-capacitor structure (first capacitor for data voltage storage and second capacitor for reference voltage storage) and a switchable voltage selection circuit. This segmentation allows independent optimization of data voltage and reference voltage, enabling expanded dynamic range while maintaining luminance accuracy in high PPI displays
Solution Approach 2:
The patent implements dynamic voltage range adjustment through a controller that selectively switches between different voltage modes. The voltage selection circuit dynamically changes the relationship between data voltage and reference voltage based on operating conditions, allowing the dynamic range to be adaptively expanded while maintaining luminance accuracy across different pixel density scenarios
2Adaptability or versatility
If capacitor coupling is used to expand dynamic range, then voltage range is improved, but offset voltage inconsistency and luminance deviation occur
Solution Approach 1:
The patent applies equipotentiality by ensuring that both the first capacitor and second capacitor maintain consistent offset voltages through identical coupling structures and symmetric circuit design. The voltage selection circuit is designed to preserve offset voltage consistency when switching between data voltage and reference voltage modes, eliminating luminance deviations caused by offset mismatches
Solution Approach 2:
The patent implements feedback mechanisms where the controller monitors the voltage states of both capacitors and adjusts the voltage selection to maintain offset voltage consistency. The dual-capacitor structure with synchronized charging/discharging paths provides inherent feedback that ensures both capacitors remain at equivalent potential levels, preventing luminance accuracy degradation
Data Source
AI summary
A display device includes: a display panel including a sub-pixel, the sub-pixel including: a first capacitor; a first transistor to generate a driving current, and including a control electrode connected to the first capacitor; a second transistor connected to the first capacitor, and to provide a data voltage or a reference voltage to the first capacitor in response to a write gate signal; and a light emitting element to receive the driving current to emit light; a data driver to selectively output the data voltage or the reference voltage to the first capacitor through a source channel; and a timing controller to control the data driver.