Voltage Adjusting Sub-Circuits for LCD Color Deviation

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Solution Overview

Problem

In liquid crystal displays (LCDs), the uneven lengths of electrical wires connecting the driving IC to the liquid crystal panel result in different impedance and voltage loss, leading to color deviation and deterioration of display quality, especially in medium and small-sized LCDs where the layout area is insufficient to maintain equal wire lengths.

Innovation Solution

The implementation of voltage adjusting sub-circuits, comprising resistors, operational amplifiers, and a sliding rheostat with a D/A converter, connected between the driving IC and the liquid crystal panel, adjusts the initial driving voltage values to ensure equal voltage delivery across all wires, preventing color deviation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If wires are curved to equal length in layout area, then voltage consistency is improved, but layout area increases

Engineering Contradiction:
Improvevoltage consistencyVSAvoidlayout area
Core Design Contradiction:
Manufacturing precisionVSArea of stationary object

Solution Approach 1:

The patent applies local quality by making different parts of the system have different properties. Specifically, wires in different regions (central vs. side parts) are allowed to have different lengths and different initial voltage values, rather than forcing all wires to be equal length. This resolves the contradiction by accepting wire length differences in the layout area while maintaining voltage consistency through localized voltage adjustment at each output port.

Inventive Principle:
Principle #3Local quality

2Loss of energy

If wire lengths are made equal, then voltage loss is reduced, but device complexity increases

Engineering Contradiction:
Improvevoltage lossVSAvoidwire layout complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent changes the voltage parameter at each output port to compensate for wire length differences. Instead of changing wire lengths to equalize voltage loss, the system adjusts the initial voltage values according to the specific impedance characteristics of each wire. This resolves the contradiction by maintaining simple wire layouts while achieving equal voltage delivery through parameter adjustment.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If voltage adjusting sub-circuits are added, then voltage consistency is improved, but device complexity increases

Engineering Contradiction:
Improvevoltage consistencyVSAvoidcircuit structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent segments the voltage adjustment function into individual sub-circuits at each output port. Rather than using a single complex centralized adjustment mechanism, each output port has its own simple voltage adjusting sub-circuit that independently compensates for wire-specific impedance differences. This resolves the contradiction by achieving voltage consistency through multiple simple localized adjustments rather than one complex system.

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution ensures consistent driving voltages are received by the liquid crystal panel, improving display quality without increasing the layout area, simplifying the LCD structure, and reducing costs.

Implementation Method 1

each of the voltage adjusting sub-circuits includes a first resistor, a second resistor, and a rheostat unit

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Implementation Method 2

each of the voltage adjusting sub-circuits further includes a first operational amplifier, a positive input terminal of the first operational amplifier is connected to the first resistor and the second resistor

Methodology Applied
Scientific EffectElectrical Amplification: Magnetic Amplifier

Data Source

PatentUS8704816B2Control circuit for adjusting an initial value of a driving voltage being transferred to a liquid crystal panel
Publication Date: 2014.04.22 TCL CHINA STAR OPTOELECTRONICS TECHNOLOGY CO LTD
  • US8704816B2 patent drawing
  • US8704816B2 patent drawing
  • US8704816B2 patent drawing

AI summary

A control circuit includes a power supply, a control IC, a liquid crystal panel, a driving integrated chip arranged between the control IC and the liquid crystal panel, and a number of voltage adjusting sub-circuits. The driving integrated chip includes a plurality of output ports for outputting a plurality of driving voltages respectively. Each voltage adjusting sub-circuit is arranged between the corresponding output port of the driving integrated chip and the liquid crystal panel for adjusting an initial value the voltage outputted from the corresponding output port before the driving voltage is transferred to the liquid crystal panel. With the voltage adjusting sub-circuits, the driving voltages received by the liquid crystal panel have the same value to avoid the color deviation of the images displayed in the liquid crystal panel. This improves the display effect of the liquid crystal panel under without increasing the layout area.