All-Transistor Scan Driver for OLED Displays
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Solution Overview
Problem
The integration of PMOS or NMOS transistors in organic light emitting displays is hindered by the need for external CMOS scan drivers, increasing the size, weight, and manufacturing complexity, as well as costs due to the use of different transistor types for pixel and scan driver circuits.
Innovation Solution
A scan driver configured using either PMOS or NMOS transistors, matching the transistor type used in the pixel circuit, allowing for the same process to form both the pixel and scan driver on a substrate, thereby simplifying the manufacturing process and reducing size and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a typical CMOS scan driver including both PMOS and NMOS transistors is used, then the scan driver can be formed as an external driver, but the size and weight of the organic light emitting display are increased
Solution Approach 1:
The patent merges the scan driver circuit with the pixel circuit by integrating the scan driver directly into the display substrate using the same transistor type (all PMOS or all NMOS). This eliminates the need for separate external CMOS scan drivers, thereby reducing the overall size and weight of the display while maintaining scan driver functionality.
Solution Approach 2:
The patent creates a universal transistor design that serves dual purposes: the same PMOS or NMOS transistors are used both in the pixel circuits and in the scan driver circuits. This multi-functional approach allows a single transistor type to fulfill multiple roles, reducing the need for additional components and reducing weight.
2Reliability
If a typical CMOS scan driver including both PMOS and NMOS transistors is used, then the scan driver can be formed as an external driver, but the process complexity is increased
Solution Approach 1:
The patent merges the scan driver circuit with the pixel circuit by integrating the scan driver directly into the display substrate using the same transistor type (all PMOS or all NMOS). This eliminates the need for separate external CMOS scan drivers, thereby reducing the overall size and weight of the display while maintaining scan driver functionality.
Solution Approach 2:
The patent employs homogeneity by using the same transistor type (either all PMOS or all NMOS) for both pixel circuits and scan driver circuits. This uniform approach simplifies the manufacturing process by eliminating the need to handle and process two different transistor types, thereby reducing process complexity.
3Reliability
If a typical CMOS scan driver including both PMOS and NMOS transistors is used, then the scan driver can be formed as an external driver, but costs are increased
Solution Approach 1:
The patent merges the scan driver circuit with the pixel circuit by integrating the scan driver directly into the display substrate using the same transistor type (all PMOS or all NMOS). This eliminates the need for separate external CMOS scan drivers, thereby reducing the overall size and weight of the display while maintaining scan driver functionality.
Solution Approach 2:
The patent employs homogeneity by using the same transistor type (either all PMOS or all NMOS) for both pixel circuits and scan driver circuits. This uniform approach simplifies the manufacturing process by eliminating the need to handle and process two different transistor types, thereby reducing process complexity and manufacturing costs.
4Reliability
If different transistor types are used for pixel and scan driver circuits, then the scan driver can function properly, but the manufacturing process becomes more complex
Solution Approach 1:
The patent employs homogeneity by using the same transistor type (either all PMOS or all NMOS) for both pixel circuits and scan driver circuits. This uniform approach simplifies the manufacturing process by eliminating the need to handle and process two different transistor types, thereby reducing process complexity while maintaining proper scan driver functionality through careful circuit design.
Data Source
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AI summary
A scan driver includes a plurality of stages connected to each other in series, each of the stages comprised of either all NMOS transistors, or all PMOS transistors, and configured to receive a clock signal, a clock bar signal, and an input signal. Each stage includes a first circuit that is configured to store a first supply voltage and a second supply voltage in response to the input signal and one of the clock signal or the clock bar signal. The first supply voltage and the second supply voltage each correspond to a voltage of the input signal, and provide a first output signal that corresponds to the second supply voltage in response to the second supply voltage being output from a previous stage of the series of stages, and the other of the clock signal or the clock bar signal.