Demultiplexer Initialization for OLED Data Line Voltage Control
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Solution Overview
Problem
Existing organic light emitting display devices face challenges in varying the voltage of data lines during scan signal supply, which limits the use of demultiplexers and affects pixel performance, as voltages charged to parasitic capacitors beforehand prevent voltage variation during scan signal periods.
Innovation Solution
The implementation of demultiplexers and an initializing unit that supplies an initial power source voltage to data lines, allowing voltage changes during scan signal periods, with demultiplexers delivering data signals to data lines and the initializing unit providing a voltage from an initial power source, enabling efficient data signal transmission and pixel operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data signals are supplied to data lines before scan signal period, then data signals can be stored in parasitic capacitors, but voltage of data lines cannot be varied during scan signal supply
Solution Approach 1:
The horizontal period is divided into multiple sub-periods (first sub-period for data signal supply, second sub-period for scan signal supply, third sub-period for initialization). This temporal segmentation allows data signals to be supplied and stored in parasitic capacitors during the first sub-period, while enabling voltage variation of data lines during the third sub-period without interfering with the second sub-period's scan signal operation.
Solution Approach 2:
Data signals are supplied to data lines and stored in parasitic capacitors during the first sub-period before the scan signal period. This preliminary action ensures that data is ready for pixel transmission during the second sub-period, while the third sub-period can independently perform voltage initialization without affecting the stored data.
2Productivity
If demultiplexers are used to deliver data signals to data lines, then data transmission efficiency is improved, but device complexity increases
Solution Approach 1:
The demultiplexer is designed to perform multiple functions: delivering data signals to data lines during the first sub-period, and enabling voltage variation of data lines during the third sub-period. By integrating these functions into a single component, the patent improves data transmission efficiency while avoiding the need for separate circuits for each function, thus controlling overall device complexity.
3Reliability
If voltage of data lines is fixed beforehand, then parasitic capacitors can store data signals, but pixel brightness cannot be optimized
Solution Approach 1:
The voltage of data lines is changed from a fixed value to a dynamic value that can be varied during the third sub-period. The initializing unit supplies an initial power source voltage to data lines, which can be different from the data signal voltage. This dynamic voltage adjustment allows optimization of pixel brightness while maintaining reliable data signal storage in parasitic capacitors during the first sub-period.
Data Source
AI summary
An organic light emitting display device for transmitting data using demultiplexers is provided. The organic light emitting display device includes: a demultiplexer controller for sequentially supplying control signals during a first period of a horizontal period; scan lines for transferring a scan signal; a scan driving unit for supplying the scan signal to the scan lines during a second period of the horizontal period; output lines for transferring data signals; a data driving unit for sequentially supplying the data signals to respective output lines during the first period; data lines for transferring the data signals; demultiplexers coupled to the respective output lines, for delivering the data signals to the data lines in response to the control signals; an initializing unit coupled to the data lines and an initial power source; and pixels located at crossing regions of the scan lines and the data lines.