Display Pixel Circuit With Dual-Level Scan Signals for Leakage Control
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Solution Overview
Problem
The issue of reduced image quality due to voltage leakage in storage capacitors of pixel circuits, which is exacerbated by transistor leakage, and the increased circuit area required for additional scan signals in narrow bezel displays, is a challenge in display technology.
Innovation Solution
A display device with a pixel circuit that includes P-type and N-type transistors, where the scan driver outputs two scan signals with different enable voltages to control the pixel circuit, utilizing the low leakage current characteristic of N-type transistors to reduce voltage loss and improve image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If voltage maintained by storage capacitor is decreased due to leakage in transistor, then circuit area can be reduced, but image quality deteriorates
Solution Approach 1:
The pixel circuit is divided into multiple transistor components (P-type and N-type transistors) with distinct functions. The N-type transistor is specifically assigned to maintain voltage with low leakage, while the P-type transistor handles signal transmission. This segmentation allows each component to be optimized for its specific function, preventing voltage degradation without increasing overall circuit area.
Solution Approach 2:
Different transistors are assigned different characteristics tailored to their specific functions. The N-type transistor is positioned and configured to provide low leakage current where voltage maintenance is critical, while the P-type transistor is configured for signal transmission. This local optimization of component characteristics resolves the contradiction between area efficiency and image quality.
2Reliability
If additional scan signals are added to control pixel circuit, then image quality can be improved, but circuit area increases
Solution Approach 1:
The scan driver circuit is designed to generate multiple scan signals (first scan signal and second scan signal) that serve different control functions for the pixel circuit. These signals are generated within the existing driver structure, allowing multi-functional control without requiring separate dedicated circuits for each signal type, thus minimizing area increase.
Solution Approach 2:
The patent utilizes temporal dimension by generating scan signals at different timing stages (first scan signal for P-type transistor, second scan signal for N-type transistor) rather than requiring separate spatial circuits. This time-multiplexed approach allows multiple control functions to coexist within the same physical circuit area.
Data Source
AI summary
A display device includes a pixel circuit and a stage of a scan driver. The stage of the scan driver is electrically coupled to the pixel circuit. The stage of the scan driver is configured to output a first scan signal and a second scan signal to the pixel circuit. A first enable voltage of the first scan signal is at a first logic level, and a first disable voltage of the first scan signal is at a second logic level. A second enable voltage of the second scan signal is at the second logic level.