OLED Display Shift Register Latch Circuit Threshold Compensation
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Solution Overview
Problem
OLED display devices suffer from image retention due to hysteresis effects in driving transistors, leading to variations in light emission intensity and ghost images, which existing technologies have not adequately addressed.
Innovation Solution
A display device configuration incorporating a shift register circuit and multiple latch circuits to generate and output control signals for pixel circuits, allowing for separate threshold voltage compensation and data write periods, reducing the need for additional circuitry and minimizing image retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If threshold voltage compensation is performed for driving transistors, then manufacturing precision is improved, but device complexity increases due to additional correction circuits
Solution Approach 1:
The patent merges the threshold voltage compensation function with the existing pixel circuit structure by utilizing the storage capacitor and switch transistors already present in the pixel circuit. The compensation is achieved through software algorithm processing of voltage levels during the data write period, eliminating the need for separate hardware correction circuits while maintaining manufacturing precision.
Solution Approach 2:
The patent replaces the traditional hardware-based correction circuit with a software-based compensation method. Instead of using additional electronic components to correct threshold voltage variations, the system uses algorithm processing to calculate and adjust voltage levels during the data write period, thereby reducing device complexity while maintaining compensation effectiveness.
2Manufacturing precision
If image retention is reduced by extending threshold voltage compensation period, then manufacturing precision is improved, but productivity decreases due to longer compensation time
Solution Approach 1:
The patent performs threshold voltage compensation calculations and voltage level adjustments during the data write period, which is a time when the pixel circuit is already in an active state. By conducting compensation actions preliminarily during this overlapping period rather than sequentially after data writing, the system extends compensation effectiveness without significantly increasing the overall frame time, thus maintaining productivity.
Solution Approach 2:
The patent dynamically adjusts the compensation process to occur during the data write period when the pixel circuit is accessible, rather than using a fixed separate compensation phase. This dynamic timing allows the compensation to be integrated into the existing frame structure, maintaining frame rate while achieving thorough voltage compensation.
3Manufacturing precision
If separate threshold voltage compensation and data write periods are implemented, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent combines the threshold voltage compensation process with the data write period by utilizing the same pixel circuit components (storage capacitor, switch transistors) for both functions. The compensation is achieved through voltage level processing during the data write operation, eliminating the need for separate timing control mechanisms and reducing overall device complexity.
Solution Approach 2:
The patent makes the pixel circuit components serve multiple functions: the storage capacitor and switch transistors are used both for data writing and for threshold voltage compensation. This multi-functionality allows the system to achieve separate compensation and data write operations without requiring additional dedicated circuits or complex timing control, thereby reducing device complexity.
Data Source
AI summary
Each of latch circuits outputs a pulse of a first kind of signal to a pixel circuit row. Shift register units serially output pulses of a second kind of signal. Each of the latch circuits receives the pulse of the second kind of signal from a first shift register unit and the pulse of the second kind of signal from a second shift register unit of a later stage than the first shift register unit. The pulse of the first kind of signal from each of the latch circuits changes from a first potential level to a second potential level in response to the pulse of the second kind of signal from the first shift register unit and changes from the second potential level to the first potential level in response to the pulse of the second kind of signal from the second shift register unit.