Liquid Crystal Driving Apparatus Bipolar Waveform Power Reduction
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Solution Overview
Problem
The existing liquid crystal driving apparatuses for polymer network liquid crystals consume high power due to significant charge-and-discharge currents, which is a challenge for devices with capacity-constrained power sources, such as portable devices.
Innovation Solution
A liquid crystal driving apparatus with a drive circuit that applies a rectangular wave voltage to the counter electrodes, inverting the phase and shifting it by a minute time Δt, reducing the consumption current by half compared to traditional methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional rectangular wave voltage is applied to drive the liquid crystal, then the liquid crystal can be effectively switched between ON and OFF states, but the power consumption is high due to significant charge-and-discharge currents
Solution Approach 1:
The patent applies periodic rectangular wave voltages to drive the liquid crystal, but introduces a novel approach by alternating the polarity of the voltage in each cycle. The drive circuit applies positive voltage during one half-cycle and negative voltage during the next half-cycle, creating a symmetric alternating pattern that reduces net charge accumulation and minimizes charge-and-discharge currents, thereby reducing power consumption while maintaining effective switching
Solution Approach 2:
The patent changes the voltage parameter by applying symmetric positive and negative voltages instead of traditional unipolar voltages. This parameter change transforms the driving waveform from a traditional single-polarity rectangular wave to a bipolar alternating rectangular wave, which fundamentally alters the charge distribution pattern and reduces the magnitude of charge-and-discharge currents
2Productivity
If the segment electrodes are turned ON frequently to update display content, then the display can show dynamic information, but the charge-and-discharge currents increase leading to higher power consumption
Solution Approach 1:
The patent utilizes periodic rectangular wave voltages with alternating polarity to drive the liquid crystal segments. By maintaining this periodic bipolar waveform even during display updates, the system achieves frequent content changes while the symmetric voltage pattern continuously reduces charge-and-discharge currents, allowing high productivity without proportional power consumption increase
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 approach effectively reduces the power consumption required to drive the liquid crystals, allowing for efficient use of power sources with capacity constraints, thereby enhancing the battery life of portable devices.
Implementation Method 1
when signals are applied to the segment electrode 13, i.e., in an ON state, the liquid-crystal molecules of the polymer network liquid crystal layer 15 are aligned in the direction of an electric field in the pixel region between this segment electrode 13 and the common electrode 14
Implementation Method 2
The main factor in power consumption of the polymer network liquid crystal 10 is a charge-and-discharge current that follows the capacitance between the common electrode 14 and the segment electrodes 13, 13, . . . when the segment electrodes 13, 13, . . . are turned ON
Data Source
AI summary
There is provided a liquid crystal driving apparatus which includes a first substrate and a second substrate, a first counter electrode that is provided on the first substrate so as to face the second substrate, a second counter electrode that is provided on the second substrate so as to face the first substrate, a polymer network liquid crystal layer that is enclosed between the first substrate and the second substrate, and a drive circuit configured to ON-drive the first counter electrode and the second counter electrode by applying a rectangular wave voltage for driving the second counter electrode upon inverting a phase and shifting forward or backward by a minute time Δt with respect to a rectangular wave voltage for driving the first counter electrode.