LCD Buffer Circuit for Excitation Voltage Removal

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Solution Overview

Problem

Liquid crystal display devices (LCDs) are prone to malfunction due to excitation voltage, such as static electricity, being input into the option signal, which affects the timing controller's reset terminal and causes improper reset operations.

Innovation Solution

A buffer is introduced between the input unit and the controller to remove excitation voltage from the option signal, utilizing transistors and filters to prevent high-frequency components from reaching the timing controller, ensuring the option signal is only processed when the voltage level is safe.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the option signal is directly connected to the timing controller, then the timing controller can respond quickly to option signals, but the timing controller is vulnerable to excitation voltage from external sources

Engineering Contradiction:

Improveresponse speed to option signalVSAvoidstability of timing controller

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

A buffer circuit is introduced as an intermediary component between the option signal input terminal and the timing controller. The buffer includes a transistor whose gate receives the option signal, and whose source/drain terminals connect to the timing controller's option pin. This intermediary structure allows the timing controller to respond to option signals while isolating it from direct exposure to external excitation voltage.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The buffer circuit provides beforehand cushioning by filtering and conditioning the option signal before it reaches the timing controller. The transistor in the buffer acts as a protective barrier that cushions the timing controller against excitation voltage spikes and static electricity from external sources, preventing malfunction before they can occur.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If a buffer is introduced to remove excitation voltage, then the timing controller is protected from malfunction, but the signal transmission path becomes more complex

Engineering Contradiction:

Improvestability of timing controllerVSAvoidcomplexity of signal transmission path

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The buffer serves as a simple intermediary element that adds minimal complexity to the signal path. Rather than implementing a complex filtering system, a single transistor-based buffer is used to perform the protection function, maintaining simplicity while achieving reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The buffer changes the electrical parameters of the option signal before it reaches the timing controller. By adjusting voltage levels and filtering high-frequency components through the transistor, the buffer transforms the raw option signal into a conditioned signal that is safe for the timing controller while adding minimal structural complexity.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8259054B2Liquid crystal display device and method of controlling the same for removing excitation voltage

Publication Date: 2012.09.04 LG DISPLAY CO LTD

AI summary

A liquid crystal display device includes a liquid crystal panel, a driver that drives the liquid crystal panel, an input unit that inputs an option signal from outside the liquid crystal device, a controller that controls the driver and performs an option function corresponding to the option signal, and a buffer disposed between the input unit and the controller that removes an excitation voltage from the option signal output from the input unit.