Bidirectional Shift Register for Narrowing Display Picture-Frame
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Solution Overview
Problem
In organic EL display devices, switching between vertical scanning directions requires multiple shift registers, leading to increased circuit size and a widened picture-frame region, making it difficult to achieve higher definition and miniaturization.
Innovation Solution
A scanning line drive circuit with a bidirectional shift register and switching circuits allows for simultaneous activation of scanning lines during both normal and reverse order scanning, reducing the number of required circuits and enabling switching between vertical scanning directions without increasing the circuit area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If switching between vertical scanning directions is implemented using multiple shift registers, then the ability to switch scanning directions is achieved, but the circuit size increases and the picture-frame region widens
Solution Approach 1:
A single shift register is designed to perform multiple functions by switching its scanning direction. The shift register can operate in both normal scanning mode (top to bottom) and reverse scanning mode (bottom to top), eliminating the need for separate shift registers for each direction. This multi-functional design reduces the overall circuit area while maintaining the capability to switch between different vertical scanning directions.
Solution Approach 2:
The invention merges the functionality of multiple shift registers (one for normal scanning, one for reverse scanning) into a single unified shift register. By combining these separate circuits into one, the total circuit area is reduced, and the picture-frame region is narrowed, while still providing the required switching capability between different scanning directions.
2Reliability
If multiple shift registers are used to drive different scanning lines during direction switching, then proper timing control is achieved, but the device complexity increases
Solution Approach 1:
The single shift register is designed with multi-functional capability to drive different scanning lines with proper timing. By incorporating direction switching control within the same shift register structure, the patent maintains accurate timing control for both normal and reverse scanning while avoiding the complexity of managing multiple separate shift registers and their associated control circuits.
Solution Approach 2:
The shift register incorporates dynamic switching capability that allows it to adapt its scanning direction based on control signals. This dynamic behavior enables the same circuit to perform different functions (normal scanning or reverse scanning) as needed, maintaining timing accuracy without requiring static separate circuits for each mode.
Data Source
AI summary
Narrowing of a picture-frame of a display device that can perform switching between vertical scanning directions is implemented. A gate driver (21) includes a shift register (211) including a plurality of unit circuits including n unit circuits connected to write control lines; a first scanning order switching circuit (212) including a plurality of first switching circuits respectively corresponding to the plurality of unit circuits; and a second scanning order switching circuit (213) including n second switching circuits connected to initialization control lines. The first scanning order switching circuit (212) controls operation of the shift register (211) based on scanning order instruction signals. Each second switching circuit applies, based on the scanning order instruction signals, an output signal from a unit circuit on a previous stage side or an output signal from a unit circuit on a subsequent stage side, as a second scanning signal, to an initialization control line.