Bi-directional Shift Register for LCD Reverse Scan

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Solution Overview

Problem

Traditional LCD devices are uni-directional, failing to function normally when scanning gate lines in reverse direction, limiting their versatility and functionality.

Innovation Solution

A bi-directional shift register is designed with multiple shift register units coupled in series, utilizing multiple clock signals and input/output circuits to enable scanning in both forward and reverse directions, allowing each shift register unit to operate based on the outputs of adjacent units in both directions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a traditional uni-directional shift register is used, then the device structure is simple and manufacturing is easier, but the device cannot function normally in reverse scan mode, limiting versatility

Engineering Contradiction:

Improvescan direction capabilityVSAvoidshift register structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The shift register unit is designed to perform multiple functions by incorporating dual input circuits (first input circuit for forward scan, second input circuit for reverse scan), dual pull-down circuits, and multi-phase clock signal support. This allows the same hardware structure to enable scanning in both forward and reverse directions, achieving versatility without requiring separate shift registers for each direction

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The shift register employs dynamic control through multiple clock phases (first clock phase, second clock phase, third clock phase) that dynamically switch the operational state of different circuits. The pull-down circuits are selectively activated based on the scanning direction and clock phase, allowing the device to adapt its behavior dynamically rather than being fixed in a single operational mode

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If a bi-directional shift register with multiple input circuits is implemented, then scanning in both directions is enabled, but the device complexity and manufacturing difficulty increase

Engineering Contradiction:

Improvebi-directional scanning capabilityVSAvoidfabrication process

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The shift register unit is segmented into distinct functional modules: input circuits, pull-up circuits, pull-down circuits, and output circuits. Each module has a specific function and can be independently designed and fabricated. This segmentation allows for systematic layout and manufacturing processes, reducing the complexity that would otherwise arise from the bi-directional functionality

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different parts of the shift register unit have specialized structures optimized for their specific functions. For example, the pull-down circuits have control ends specifically coupled to receive signals from adjacent stages, and the input circuits are positioned to receive signals from either forward or reverse directions. This local optimization allows each component to be manufactured with standard processes while achieving complex overall functionality

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS8406372B2Bi-directional shift register

Publication Date: 2013.03.26 AU OPTRONICS CORP

AI summary

A shift register of an LCD device includes a plurality of shift register units coupled in series. Each shift register unit includes an input circuit and a pull-down circuit having symmetric structures which enable the LCD device to function in a forward-scan mode and a reverse-scan mode.