Emission Control Driver Using Scan Signals for OLED Displays
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Solution Overview
Problem
Conventional emission control drivers for organic light emitting display devices require a large number of transistors and clock signals, increasing manufacturing costs and mounting area, and complicating reliability due to the complexity of the circuit structure.
Innovation Solution
An emission control driver that generates emission control signals using scan signals, reducing the number of transistors and eliminating the need for separate clock signals by utilizing a simplified circuit structure with input and output circuits controlled by voltages from scan signals, thereby reducing the number of transistors and simplifying the circuit design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional emission control driver uses four or more clock signals to drive each stage, then the emission control function is achieved, but the number of transistors increases and manufacturing cost increases
Solution Approach 1:
The patent extracts and eliminates the clock signal input from the emission control driver stages. Instead of using four or more clock signals as in conventional designs, the invention uses only two scan signals (Sn and Sn+1) to control the emission control signals, thereby removing the complex clock signal distribution network and reducing the number of transistors required in each stage.
Solution Approach 2:
The scan signals are given multiple functions: they serve both as scan control signals for selecting pixels and as emission control signals for controlling the emission timing of OLEDs. By making the scan signals multi-functional, the patent eliminates the need for separate clock signals dedicated solely to emission control, thereby reducing circuit complexity and transistor count.
2Reliability
If each stage includes a large number of transistors to process multiple clock signals, then the emission control signals can be generated, but the mounting area increases
Solution Approach 1:
The patent removes the clock signal processing circuitry from each stage, extracting only the essential scan signal inputs (Sn and Sn+1). This extraction eliminates numerous transistors that would otherwise be required to process multiple clock signals, thereby significantly reducing the mounting area of the emission control driver.
Solution Approach 2:
The patent merges the scan control function and emission control function into a unified circuit structure. By combining these functions and using the same scan signals for both purposes, the invention reduces the total number of transistors and reduces the mounting area required for the emission control driver.
3Reliability
If four or more clock signals are used to drive each stage, then the emission control function is maintained, but the manufacturing cost increases
Solution Approach 1:
The patent extracts and eliminates the complex clock signal distribution system, reducing the number of signal lines and transistors that need to be manufactured. This simplification directly reduces manufacturing complexity and cost while maintaining the emission control function through the use of only two scan signals.
Solution Approach 2:
By making scan signals multi-functional (serving both scan control and emission control purposes), the patent reduces the total number of signal lines and circuit components required. This universality simplifies the manufacturing process and reduces costs associated with producing and testing complex clock signal distribution networks.
4Reliability
If a conventional emission control driver uses multiple clock signals and large number of transistors, then the emission control signals can be supplied to emission control lines, but the circuit structure becomes complex reducing reliability
Solution Approach 1:
The patent extracts and removes the clock signal input stage and associated circuitry from the emission control driver. By using only two scan signals instead of multiple clock signals, the invention simplifies the circuit structure, reduces the number of transistors, and improves reliability while maintaining the ability to supply emission control signals to emission control lines.
Data Source
AI summary
An emission control driver includes a plurality of stages, each of the plurality of stages including an output terminal coupled to a corresponding one of the emission control lines; input terminals respectively coupled to two or more scan lines of the scan lines for generating a corresponding one of the emission control signals; an input circuit for controlling voltages at a first node and a second node corresponding to scan signals supplied from the two or more scan lines; and an output circuit coupled to the input circuit, the output circuit for controlling the corresponding one of the emission control signals according to the voltages at the first node and the second node.