AMOLED Display Timing Schedule for Threshold Voltage Generation
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Solution Overview
Problem
Active-matrix organic light-emitting diode (AMOLED) displays face challenges in generating an accurate threshold voltage for drive transistors, particularly in large-area displays, which requires a significant timing budget and results in higher power consumption and increased implementation costs due to the need for additional operating cycles and controlling signals.
Innovation Solution
A display system with a pixel array that includes a light emitting device, a capacitor, a switch transistor, and a drive transistor, featuring a first driver for programming and a second driver for independently controlling the threshold voltage generation of the drive transistor, allowing for segmented or parallel timing schedules to extend the timing budget for threshold voltage generation without affecting programming time, and a shared signaling addressing scheme to reduce power consumption and implementation costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the VT-generation cycle is executed sequentially for each row with additional compensation voltage generation cycle, then the threshold voltage can be generated accurately, but the timing budget becomes insufficient for large-area displays and power consumption increases
Solution Approach 1:
The display is divided into multiple segments, and the VT-generation cycle is executed in parallel across different segments rather than sequentially. This allows the threshold voltage to be generated simultaneously for multiple rows, extending the timing budget without increasing the total time required for the entire display.
Solution Approach 2:
The compensation voltage generation cycle is performed in advance during the programming phase, so that when the VT-generation cycle executes, the compensation voltage is already ready. This eliminates the need for sequential execution of both cycles and reduces the overall timing requirement.
2Measurement precision
If the VT-generation cycle and compensation voltage generation cycle are executed sequentially for each row, then accurate threshold voltage can be generated, but power consumption increases due to extra operating cycles
Solution Approach 1:
The VT-generation cycle and compensation voltage generation cycle are merged into a single parallel execution phase. Instead of executing them sequentially as separate operating cycles, both cycles run simultaneously across different segments, reducing the total number of cycle transitions and associated power consumption.
Solution Approach 2:
The compensation voltage is generated in advance during the programming phase, so that when the VT-generation cycle executes, the compensation voltage is already ready. This eliminates the need for separate compensation voltage generation cycles during the VT-generation phase, reducing power consumption.
3Measurement precision
If the VT-generation cycle is executed sequentially for each row, then the threshold voltage can be generated, but the number of controlling signals increases leading to higher implementation cost
Solution Approach 1:
The segment control signals serve multiple functions: they control both the programming phase and the VT-generation phase across different segments. This multi-functionality reduces the total number of unique controlling signals required, as the same segment control lines are reused for different operations in different time periods.
Data Source
AI summary
A method and system for driving a light emitting device display is provided. The system provides a timing schedule which increases accuracy in the display. The system may provide the timing schedule by which an operation cycle is implemented consecutively in a group of rows. The system may provide the timing schedule by which an aging factor is used for a plurality of frames.