OLED Pixel Circuit with Dynamic Voltage Control for Aperture Ratio
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Solution Overview
Problem
As display technology advances, particularly in active matrix type OLED displays, there is a need for a simplified pixel structure to maintain high resolution and improve aperture ratio while managing increased pixel density and voltage control efficiently.
Innovation Solution
A pixel configuration incorporating a switching transistor, a driving transistor, a compensation transistor, a light-emitting transistor, and an organic light-emitting diode, along with a storage capacitor, where the transistors can be oxide thin film transistors, and a driving method that involves applying scan, data, and light-emitting signals to control power voltages and enable light emission, optimizing voltage levels and signal timing to enhance display performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the pixel structure is simplified to maintain high resolution and improve aperture ratio, then the aperture ratio and resolution are improved, but the voltage control and signal timing management become more challenging
Solution Approach 1:
The pixel circuit is divided into multiple transistors (switching transistor, driving transistor, compensation transistor, light-emitting transistor) and capacitors, each performing specific functions. This segmentation allows simplified structure while maintaining complex voltage control capabilities through coordinated operation of individual components.
Solution Approach 2:
The patent implements dynamic voltage control by sequentially changing power voltages between high and low levels during different time periods. The power supply unit dynamically switches voltage levels for first and second power lines based on the operating phase (reset, data writing, or light emission), enabling simplified structure with adaptive voltage management.
2Measurement precision
If the number of pixels is increased to maintain high resolution in larger displays, then the resolution is improved, but the pixel density and voltage control management become more difficult
Solution Approach 1:
The patent employs universal voltage control mechanisms where the same power supply unit and driver circuits manage voltage for multiple pixels simultaneously. The scan driver, data driver, and power supply unit operate universally across all pixels, enabling high pixel density without proportionally increasing control complexity.
Solution Approach 2:
The patent implements periodic voltage control cycles where power voltages are sequentially changed between high and low levels in repeated time periods. This periodic operation allows efficient management of high pixel density displays through time-multiplexed voltage control, reducing the need for complex simultaneous control of all pixels.
3Ease of manufacture
If oxide thin film transistors are used to simplify the pixel structure, then the manufacturing process is improved, but the transistor performance and voltage control precision may be compromised
Solution Approach 1:
The patent compensates for oxide thin film transistor characteristics by dynamically changing operating parameters, particularly voltage levels. The power supply unit sequentially changes power voltages between high and low levels, and the driver circuits adjust signal timings to compensate for any performance limitations of oxide thin film transistors, maintaining reliable operation while benefiting from simplified manufacturing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration simplifies the pixel structure, improves the aperture ratio, and ensures high resolution by effectively managing power voltages and signal timing, enabling efficient light emission and data storage within the display device.
Implementation Method 1
The OLED includes an anode layer and cathode layer forming an electric field, and an organic light-emitting material emitting light by the electric field
Data Source
AI summary
A display device is disclosed. In one aspect, the device includes a plurality of pixels, a scan driver sequentially applying scan signals at a gate-on voltage to a plurality of scan lines connected to a plurality of pixels and a data driver applying data signals to a plurality of data lines connected to a plurality of pixels in response to the scan signals at the gate-on voltage. The device also includes a power supply unit sequentially changing first power voltages at a high level voltage into a low level voltage and applying the changed voltages, and sequentially changing second power voltages at the low level voltage into the high level voltage and applying the changed voltages. The device further includes a light-emitting signal unit sequentially applying light-emitting signals at the gate-on voltage to a plurality of light-emitting lines connected to a plurality of pixels.