Liquid Crystal Display Latch Circuit Positioning for Signal Line Stability

Solution Overview

Problem

The reliability of liquid crystal display apparatuses is compromised due to current leakage and increased wiring resistance in signal lines, particularly in the least significant bit signal line, leading to progressive failure over time, which affects manufacturing yield and display quality.

Innovation Solution

The liquid crystal display apparatus is designed with a shift register unit and latch unit configuration where the first latch circuit for the least significant bit is positioned closer to the comparators than the most significant bit latch circuit, reducing the length of the first bit signal line and minimizing the impact of current leakage and resistance increases, thereby enhancing reliability and manufacturing yield.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the first latch circuit for the least significant bit is positioned farther from the comparators, then the wiring layout is more regular and easier to manufacture, but the signal line length increases causing current leakage and increased wiring resistance leading to progressive failure

Engineering Contradiction:

Improvewiring layout regularityVSAvoidsignal line stability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies local quality by making different parts of the wiring layout have different characteristics. Specifically, the first bit signal line (least significant bit) is routed with a shorter length and different path compared to other bit signal lines, optimizing it for reliability while other lines maintain regular layout patterns for ease of manufacture.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Instead of maintaining uniform wiring layout for all bit signal lines, the patent inverts the approach by deliberately creating an asymmetric layout where the first bit signal line has different routing characteristics (shorter length) compared to other lines, prioritizing reliability over uniformity for that specific critical signal.

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If the first latch circuit for the least significant bit is positioned closer to the comparators, then the signal line length is reduced minimizing current leakage and resistance, but the wiring layout becomes less regular and more complex to manufacture

Engineering Contradiction:

Improvesignal line stabilityVSAvoidwiring layout regularity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies local quality by making different parts of the wiring layout have different characteristics. Specifically, the first bit signal line (least significant bit) is routed with a shorter length and different path compared to other bit signal lines, optimizing it for reliability while other lines maintain regular layout patterns for ease of manufacture.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Instead of maintaining uniform wiring layout for all bit signal lines, the patent inverts the approach by deliberately creating an asymmetric layout where the first bit signal line has different routing characteristics (shorter length) compared to other lines, prioritizing reliability over uniformity for that specific critical signal.

Inventive Principle:

Principle #13The other way round (Inversion)

3Quantity of substance

If the signal line length is increased, then the wiring can accommodate more signals, but the current leakage and wiring resistance increase causing progressive failure over time

Engineering Contradiction:

Improvenumber of signal linesVSAvoidsignal line stability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent applies local quality by making different parts of the wiring layout have different characteristics. Specifically, the first bit signal line (least significant bit) is routed with a shorter length and different path compared to other bit signal lines, optimizing it for reliability while other lines maintain regular layout patterns for ease of manufacture.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS11417290B2Liquid crystal display apparatus and method of manufacturing the same

Publication Date: 2022.08.16 JVC KENWOOD CORP

AI summary

A liquid crystal display apparatus includes a shift register unit that sequentially takes in a video signal including s-bit width for the number of columns of a plurality of pixels, a 1-line latch unit that concurrently outputs a plurality of the video signals taken by the shift register unit, comparator units that convert the plurality of video signals output from the 1-line latch unit into a plurality of analog voltages, respectively, and an analog switch unit that switches whether or not the plurality of analog voltages are supplied to the plurality of data lines, respectively.