Bidirectional Shift Register for Fewer LCD Gate Drivers

Solution Overview

Problem

Conventional LCDs with double frame rate require multiple gate drivers, leading to increased costs and reduced yield due to the inability to reduce the number of gate drivers.

Innovation Solution

A shift register and gate driving circuit with bi-directional transmission function, utilizing multiple shift register units and switches to generate and transmit gate driving signals efficiently, reducing the need for multiple gate drivers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple gate drivers are used to achieve double frame rate functionality, then the display performance is improved, but the fabrication cost increases and yield decreases

Engineering Contradiction:

Improveframe rateVSAvoidnumber of gate drivers

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The shift register is designed with bidirectional transmission capability, allowing a single gate driver to serve multiple scanning directions (up-scanning and down-scanning). The shift register can transmit enabling signals in either direction based on control signals, making one gate driver universal for both scanning modes, thereby reducing the total number of gate drivers needed while maintaining double frame rate functionality

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The gate driver incorporates dynamic switching mechanisms with switches that can change connection states based on control signals. The shift register dynamically switches between transmitting enabling signals in up-scanning direction or down-scanning direction, allowing the system to adapt between different scanning modes and reduce the number of static gate drivers required

Inventive Principle:

Principle #15Dynamics

2Productivity

If multiple gate drivers are used to achieve double frame rate functionality, then the display performance is improved, but the fabrication cost increases

Engineering Contradiction:

Improveframe rateVSAvoidfabrication cost

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The shift register is designed with bidirectional transmission capability, allowing a single gate driver to serve multiple scanning directions (up-scanning and down-scanning). The shift register can transmit enabling signals in either direction based on control signals, making one gate driver universal for both scanning modes, thereby reducing the total number of gate drivers needed while maintaining double frame rate functionality

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the functions of multiple gate drivers into a single gate driver with bidirectional shift register. The up-scanning enabling signal path and down-scanning enabling signal path are merged into one shared shift register structure, reducing component count and fabrication complexity while maintaining both scanning capabilities

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS20090102778A1Shift register, gate driving circuit with bi-directional transmission function, and LCD with double frame rate

Publication Date: 2009.04.23 AU OPTRONICS CORP

AI summary

A shift register applied on a double-frame-rate LCD is provided. The LCD includes an upper display area with c gate lines, a lower display area with d gate lines, and a gate driving circuit. The gate driving circuit includes a first shift register coupled to the corresponding x gate lines of the upper display area, a second shift register coupled to the corresponding y lines of the lower display area, and a third shift register coupled to the corresponding (c-x) gate lines of the upper display area and the corresponding (d-y) gate lines of the lower display area.