Liquid Crystal Display Power Supply Selection for Peak Current Reduction
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Solution Overview
Problem
Existing electro-optic apparatuses face increased power consumption due to the need for high driving capacity power supplies to handle peak currents during AC driving of liquid crystals, primarily because the counter electrode potential is inverted, leading to increased load capacity.
Innovation Solution
An electro-optic apparatus with a power supply selecting device that switches power supplies based on the polarity signal logic, allowing the electric field between pixel and counter electrodes to be switched without inverting the counter electrode potential, thereby reducing peak current and power consumption by using a less capable power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the counter electrode potential is inverted to achieve AC driving of liquid crystals, then the electro-optic material can be driven with alternating current, but the load capacity of the counter electrode increases and peak current during inversion operation increases
Solution Approach 1:
The patent divides the electrode system into two independent groups: scan lines (which perform polarity inversion) and counter electrodes (which maintain constant potential). This segmentation allows the polarity inversion function to be isolated to the scan lines, eliminating the need for counter electrode inversion and thereby reducing peak current requirements while maintaining AC driving capability.
2Reliability
If the counter electrode potential is inverted synchronously with the polarity signal, then AC driving is achieved, but the power supply driving capacity must be sufficiently high to handle peak current during inversion
Solution Approach 1:
The patent extracts the polarity inversion function from the counter electrode system and assigns it exclusively to the scan line system. By taking out the inversion operation from the counter electrodes, the power supply only needs to handle the baseline operating current without the additional peak current demands of simultaneous counter electrode inversion, thereby reducing power supply driving capacity requirements.
3Reliability
If high driving capacity power supplies are used to handle peak currents during counter electrode inversion, then AC driving can be maintained, but power consumption increases
Solution Approach 1:
By segmenting the polarity inversion function to scan lines only, the system eliminates the need for high-capacity power supplies that would be required to drive simultaneous counter electrode inversion. This results in lower power consumption while maintaining AC driving capability, as the power supply only needs to handle steady-state current requirements.
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 reduces power consumption by minimizing the driving capacity of the power supply required, while maintaining AC driving of the electro-optic material, and simplifies the construction by eliminating the need for large load capacity counter electrodes.
Implementation Method 1
electro-optic material disposed between respective pixel electrodes and respective counter electrodes
Data Source
AI summary
To provide an electro-optic apparatus, a driving method for the same, and an electronic appliance that can reduce power consumption, a liquid crystal display device includes a plurality of scan lines, a plurality of data lines, pixel electrodes disposed at each intersection of the scan lines and the data lines, and counter electrodes disposed facing the pixel electrodes, with the counter electrodes being set at a predetermined potential. A memory circuit stores logic corresponding to a tone of a data signal supplied from a data line to the pixel electrode in accordance with logic of a polarity signal. A power supply selecting circuit switches the power supply supplied to the memory circuit based on switches in the logic of the polarity signal. The read circuit switches a read of logic stored in the storage circuit based on switches in the logic of the polarity signal and supplies the pixel electrode.