Display Pixel Circuit Timing for Stable Low-Frequency Luminance
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Solution Overview
Problem
Existing display devices face challenges in improving image quality and reducing power consumption, particularly in maintaining stable luminance and minimizing flicker, especially when driven at low frequencies.
Innovation Solution
The display device incorporates a specific transistor configuration and timing control signals to optimize the operation of transistors and light-emitting elements, including a first transistor connected between a driving voltage line and a second node, a sixth transistor between the second node and a common voltage line, and a fourth transistor between the second node and an initialization voltage line, with distinct gate signals applied in various periods to manage voltage levels and emission signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional transistor configuration is used in display devices, then the device structure is simpler, but image quality deteriorates due to flicker and unstable luminance
Solution Approach 1:
The pixel circuit is divided into multiple transistors (first transistor connected to driving voltage line, sixth transistor connected to common voltage line, fourth transistor connected to initialization voltage line) with distinct functional responsibilities. Each transistor handles specific voltage levels and timing periods, segmenting the control functions to achieve stable luminance output and reduce flicker.
Solution Approach 2:
The transistor configuration implements dynamic control through timing signals that activate different transistors in different periods. The first transistor operates during emission periods, the fourth transistor during initialization periods, and the sixth transistor during compensation periods, creating a dynamic system that adapts to different operational requirements to maintain image quality.
2Reliability
If driving voltage is increased to improve image quality, then luminance stability improves, but power consumption increases
Solution Approach 1:
The circuit employs periodic timing signals that cycle through different operational phases (emission, initialization, compensation) at different periods. This periodic action allows the transistors to switch between active and inactive states, enabling image quality maintenance during emission periods while reducing power consumption during non-emission periods through controlled transistor shutdown.
Solution Approach 2:
The initialization voltage line provides a lower voltage level compared to the driving voltage line, and the circuit dynamically changes voltage parameters across different timing periods. By adjusting voltage levels according to operational needs (high driving voltage during emission, lower initialization voltage during reset), the circuit maintains image quality while optimizing power consumption through parameter modulation.
3Reliability
If timing control is optimized to reduce flicker, then luminance stability improves, but device complexity increases
Solution Approach 1:
The circuit performs preliminary actions by initializing transistor states and voltage levels before emission periods begin. The fourth transistor pre-charges or pre-discharges capacitors during initialization periods, and the sixth transistor prepares compensation voltages in advance, ensuring that when emission periods start, all components are ready to maintain stable luminance without flicker.
Solution Approach 2:
The sixth transistor connected to the common voltage line implements feedback control by monitoring and adjusting voltage levels during compensation periods. This feedback mechanism detects voltage drops or deviations and corrects them in subsequent cycles, maintaining luminance stability and reducing flicker through continuous voltage regulation based on circuit state.
Data Source
AI summary
According to an aspect of the present disclosure, there is provided a display device including a first transistor connected between a driving voltage line and a second node, a sixth transistor connected between the second node and a common voltage line, a light-emitting element connected between the sixth transistor and the common voltage line, and a fourth transistor connected between the second node and an initialization voltage line.