Display Driver Voltage Sequencing for Stable Pixel Sensing
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Solution Overview
Problem
Existing display devices face issues due to differences between recovery and display data voltages during sensing periods, leading to element deterioration, visible sensing lines, and luminance differences, including luminance reduction, caused by voltage coupling and over/undercompensation.
Innovation Solution
A display device with a data driver that outputs multiple data voltages during driving and sensing periods, including a first sensing data voltage, a second recovery data voltage, and a third buffering data voltage, with varying levels to minimize voltage differences and compensate for luminance changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single data voltage is applied during sensing period, then device complexity is reduced, but luminance stability deteriorates due to voltage differences between recovery and display voltages
Solution Approach 1:
The single data voltage is segmented into three distinct voltages: first data voltage (sensing voltage), second data voltage (recovery voltage), and third data voltage (buffering voltage). Each voltage serves a specific function during different phases of the sensing period, allowing independent optimization of sensing accuracy, recovery compensation, and luminance stability without increasing overall system complexity.
Solution Approach 2:
The patent dynamically switches between different data voltages at specific timing points during the sensing period. The data driver sequentially applies the first, second, and third data voltages at predetermined intervals, allowing the system to adapt voltage levels to match different operational requirements (sensing, recovery, buffering) and maintain luminance stability throughout the sensing process.
2Stability of the object's composition
If recovery data voltage is applied to compensate for luminance decrease, then luminance stability improves, but voltage coupling effects worsen causing overcompensation or undercompensation
Solution Approach 1:
The third data voltage (buffering voltage) acts as an intermediary between the second data voltage (recovery voltage) and the fourth data voltage (display voltage). It buffers the voltage transition, reducing abrupt changes and coupling effects between different voltage levels, thereby minimizing overcompensation or undercompensation while maintaining luminance stability.
Solution Approach 2:
The third data voltage is applied in advance before the final display voltage is applied. This preliminary buffering action prepares the pixel circuit by reducing voltage differences and coupling effects beforehand, ensuring smooth transitions and preventing overcompensation or undercompensation when the final display voltage is applied.
3Measurement precision
If sensing lines are made visible for detection, then measurement precision improves, but display quality deteriorates due to visible sensing lines and luminance differences
Solution Approach 1:
The patent uses periodic scanning of sensing lines during blank periods between frame displays. Sensing operations are performed periodically rather than continuously, allowing sensing lines to be activated only when not needed for display. This enables accurate element deterioration detection while preventing visible sensing lines and luminance differences during the actual display period.
Solution Approach 2:
Sensing operations are performed in advance during blank periods before the next display frame begins. By completing sensing measurements beforehand, the system can detect element deterioration without interfering with the upcoming display, ensuring high measurement precision while maintaining display quality with no visible sensing lines.
Data Source
AI summary
Disclosed is a display device including a display panel including subpixels, and a data driver connected to the display panel, wherein the data driver outputs data voltages for displaying an image on the basis of the subpixels during a driving period of the display panel, and outputs a first data voltage, a second data voltage having a level different from the first data voltage, and a third data voltage having a level different from the second data voltage during a sensing period of the display panel.