Shift Register Circuit for OLED Display Image Smear Reduction
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Solution Overview
Problem
OLED display apparatuses suffer from image smear, particularly dynamic image smear, during the process of switching dynamic pictures, which is represented by a high motion picture response time (MPRT).
Innovation Solution
A shift register circuit is designed with an input sub-circuit, an output sub-circuit, a control sub-circuit, and a compensation sub-circuit. This circuit structure allows for the transmission of input signals, clock signals, and control signals to effectively manage the voltage at pull-up nodes, thereby reducing image smear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional shift register circuit is used in OLED display, then the circuit structure is simple, but dynamic image smear occurs due to high motion picture response time
Solution Approach 1:
The shift register circuit is divided into multiple functional sub-circuits: input sub-circuit, output sub-circuit, control sub-circuit, and compensation sub-circuit. Each sub-circuit performs a specific function to collectively reduce image smear while managing complexity through modular design.
Solution Approach 2:
The compensation sub-circuit performs preliminary action by compensating for voltage drops at the pull-up node before they affect the output signal. This proactive compensation prevents image smear by ensuring stable voltage levels during dynamic picture switching.
2Loss of time
If black image insertion process is implemented to reduce image smear, then motion picture response time is improved, but additional control signals and circuit operations are required
Solution Approach 1:
The black image insertion is implemented as a periodic action integrated into the normal scanning process. The control sub-circuit manages this periodic insertion using existing clock signals, reducing image smear without requiring separate control mechanisms.
Solution Approach 2:
The control sub-circuit is designed to perform multiple functions: it controls the output sub-circuit, manages the compensation sub-circuit, and handles black image insertion. This multi-functionality reduces the need for additional dedicated control circuits.
3Object-affected harmful factors
If compensation sub-circuit is added to manage pull-up node voltage, then image smear is reduced, but circuit complexity increases
Solution Approach 1:
The compensation sub-circuit is merged with the existing shift register structure, sharing common nodes and signals. The compensation transistor and capacitor are integrated into the pull-up node architecture, reducing overall complexity compared to a separate compensation system.
Solution Approach 2:
The compensation sub-circuit is designed to automatically compensate for voltage drops at the pull-up node without requiring external control. The compensation transistor activates based on the voltage level at the pull-up node, providing self-regulating compensation that reduces image smear.
Data Source
AI summary
A shift register circuit includes an input sub-circuit, an output sub-circuit, a control sub-circuit and a compensation sub-circuit. The input sub-circuit is configured to, under control of a first input signal received at a first input signal terminal, transmit the first input signal to a pull-up node. The output sub-circuit is configured to transmit a first clock signal received at a first clock signal terminal to a first signal output terminal under control of a voltage at the pull-up node. The control sub-circuit is configured to transmit a voltage at a first reference node to the pull-up node under control of a first control signal received at a first control signal terminal. The compensation sub-circuit is configured to transmit a voltage at a seventh node to the pull-up node under control of a seventh clock signal received at a seventh clock signal terminal.