Scan Driver Emission Control Signal Width
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Solution Overview
Problem
Conventional scan drivers for organic light emitting displays face challenges in freely controlling the width of emission control signals without affecting scan signals, leading to undesired flicker and inability to generate desired scan signals when increasing the width of the start pulse.
Innovation Solution
A scan driver that receives at least two start pulses in one frame, generating two sampling pulses and combining them with different output enable signals to produce scan and emission control signals, allowing for independent control of emission control signal width without generating multiple scan signals, using NOR and NAND gates with inverters to manage sampling pulses and output enable signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the width of the start pulse is increased to increase the width of emission control signals, then the emission control signal width is improved, but multiple scan signals are generated in one frame causing display errors
Solution Approach 1:
The invention divides the emission control signal generation into two separate phases within one frame: first emission control signals (EMI1) generated from start pulse SP1, and second emission control signals (EMI2) generated from start pulse SP2. This segmentation allows each emission control signal to be generated independently with controlled width, preventing the generation of multiple scan signals while maintaining adequate emission duration for brightness control.
2Illumination intensity
If the width of emission control signals is increased to control brightness, then brightness control capability is improved, but flicker occurs due to increased non-emission periods
Solution Approach 1:
The invention ensures continuous useful action by generating two emission control signals (EMI1 and EMI2) within one frame period, effectively utilizing the entire frame time for emission control. This continuous approach reduces non-emission periods and prevents flicker while maintaining the ability to control brightness through the width of emission control signals.
3Adaptability or versatility
If conventional scan driver structure is used with single start pulse, then device complexity is low, but ability to freely control emission control signal width is limited
Solution Approach 1:
The invention introduces dynamic elements to the scan driver structure by incorporating multiple start pulses (SP1, SP2) and corresponding emission control signals (EMI1, EMI2) that can be independently controlled. This dynamic structure allows flexible adjustment of emission control signal widths to achieve desired brightness levels while maintaining a relatively simple overall device architecture.
Data Source
AI summary
A scan driver capable of freely setting the width of emission control signals and of dividing the emission control signals at least twice in one frame to apply the emission control signals is disclosed. Embodiments of the scan driver include a shift register, receiving at least two start pulses in one frame to sequentially shift the start pulses in response to a clock signal and to thus generate at least two sampling pulses, and at least two signal generators for combining the at least two sampling pulses and at least two output enable signals with each other to supply scan signals to scan lines, and for combining the at least two sampling pulses output from the shift register with each other to supply at least two emission control signals to emission control signals lines in one frame. At least two emission control signals are supplied to emission control signal lines in one frame so that it is possible to change the brightness of the display without generating a flicker.