Display Pixel Circuit Overlapping Initialization and Emission
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Solution Overview
Problem
Current display devices face challenges in implementing accurate luminance and high-quality images due to insufficient initialization and compensation periods for data voltage and threshold voltage, leading to increased power consumption and non-uniformity of luminance, especially in high-speed driving modes for large-sized displays.
Innovation Solution
A display device and driving method that include specific periods for on-bias voltage application, reset, initialization, threshold voltage compensation, data writing, and light emission, allowing these processes to overlap and ensuring sufficient time for each step, thereby improving luminance uniformity and reducing power consumption by simplifying pixel circuit layouts and eliminating the need for additional voltage wires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-speed driving mode is used for large-sized displays, then productivity and response time are improved, but initialization period and compensation period become insufficient leading to inaccurate luminance
Solution Approach 1:
The pixel circuit performs initialization and threshold voltage compensation operations in advance during the initialization period before the data writing period. Specifically, the initialization transistor initializes the storage capacitor and the compensation transistor compensates for threshold voltage variations before data is written, ensuring that these critical operations are completed beforehand to support high-speed driving while maintaining luminance accuracy.
2Manufacturing precision
If luminance compensation and complex pixel circuit structure are used, then luminance uniformity is improved, but power consumption increases and production cost increases
Solution Approach 1:
The compensation transistor compensates for threshold voltage variations of the driving transistor in advance during the initialization period before data writing. This preliminary compensation action ensures accurate luminance control without requiring continuous complex compensation circuits, thereby reducing power consumption while maintaining luminance uniformity.
Solution Approach 2:
The patent extracts and separates the initialization and compensation functions into distinct transistor operations during the initialization period, allowing these functions to be performed independently and efficiently without requiring additional complex circuit structures, thus reducing overall power consumption while maintaining luminance uniformity.
3Adaptability or versatility
If separate voltage wire circuit is added for on-bias voltage, then pixel circuit functionality is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The data line is designed to serve multiple functions: it transfers data voltage during the data writing period and transfers on-bias voltage during the initialization period. This multi-functional use of the existing data line eliminates the need for a separate voltage wire circuit, reducing device complexity while maintaining the required pixel circuit functionality for both data writing and on-bias voltage application.
Solution Approach 2:
The patent merges the data voltage transfer function and on-bias voltage transfer function into a single data line. By controlling the timing of voltage application, the same physical wire performs both functions, thereby simplifying the overall circuit structure and reducing manufacturing complexity without compromising functionality.
4Measurement precision
If data writing period and light emitting period are separated, then data writing accuracy is improved, but response waveform and luminance uniformity deteriorate
Solution Approach 1:
The pixel circuit performs threshold voltage compensation and storage capacitor initialization in advance during the initialization period before data writing begins. This preliminary preparation ensures that when data writing and light emission occur simultaneously, the pixel circuit is already properly configured, maintaining both data writing accuracy and luminance uniformity without requiring separate periods.
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
The solution ensures accurate and uniform luminance expression, improves the response waveform of pixels, and supports high-resolution, high-speed driving while maintaining a high manufacturing yield and aperture ratio, effectively addressing the limitations of conventional display technologies.
Implementation Method 1
organic light emitting diodes of the plurality of pixels simultaneously emit light
Data Source
AI summary
A display device and a driving method thereof. The display device includes a plurality of pixels, each receiving a predetermined on-bias voltage transferred through a data line during one frame, receiving a first image data signal corresponding to the corresponding frame through the data line and storing the same, and emitting light according to a driving current that corresponds to a second image data signal that corresponds to the previous frame of the corresponding frame, and a first period for storing the first image data signal and a second period for light emission according to a driving current corresponding to the second image data signal overlap each other in one frame.