Display Device Initialization Circuit for Luminance Uniformity
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Solution Overview
Problem
Display devices face challenges in minimizing luminance differences when driving frequency changes, and in reducing hysteresis and screen dragging due to differences in on-bias and grayscale between adjacent pixels.
Innovation Solution
A display device architecture that includes specific transistor configurations and initialization voltage supply circuits, where transistors are connected to scan lines, data lines, and emission control lines, and initialization voltages are applied at different levels to stabilize pixel performance across varying frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If the display device is driven at a low frequency to improve driving efficiency and minimize power consumption, then power consumption is reduced, but luminance difference between pixels increases and display quality deteriorates
Solution Approach 1:
The patent applies preliminary action by initializing the pixel circuit before the display period at a low driving frequency. The initialization voltage is applied to the gate electrode of the driving transistor through the initialization transistor during a dedicated initialization period, ensuring the transistor is properly biased before data writing occurs. This preliminary initialization prevents luminance differences that would otherwise occur due to the extended time between frames at low frequencies.
2Productivity
If the display device is driven at a low frequency, then driving efficiency is improved, but hysteresis and screen dragging due to deviation in threshold voltage shift increase
Solution Approach 1:
The patent implements periodic action by repeatedly applying the initialization voltage to the gate electrode of the driving transistor during each frame period, regardless of the low driving frequency. The initialization transistor is periodically turned on during the initialization period to refresh the gate voltage, ensuring that threshold voltage deviations are corrected in each cycle. This periodic re-initialization maintains threshold voltage stability and prevents hysteresis and screen dragging effects that would accumulate over extended periods between frames.
Data Source
AI summary
The present inventive concept relates to a display device. Specifically, the display device according to an embodiment of the present inventive concept includes pixels; a scan driver supplying a first scan signal, a third scan signal, and a fourth scan signal at a first frequency and supplying a second scan signal at a second frequency that is a divisor of the first frequency; a data driver supplying a data signal at the second frequency; an emission driver supplying an emission control signal at the first frequency; and a timing controller.