Liquid Crystal Element Using Dual Frequency Addressing for Electronic Paper
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Solution Overview
Problem
Existing liquid crystal elements for electronic paper displays face challenges in achieving high visual recognition and low power consumption, with guest-host type liquid crystal elements requiring complex electrode structures and lacking memory properties when voltage is not applied.
Innovation Solution
A liquid crystal element utilizing dual frequency addressable smectic liquid crystal compositions with different threshold voltages, allowing independent addressing of liquid crystal layers using a single pair of electrodes, which simplifies the structure and maintains display state without voltage application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If guest-host type liquid crystal element with multiple liquid crystal layers is used to achieve wide color reproduction range, then color display performance is improved, but device complexity increases due to requirement of providing electrode for each layer
Solution Approach 1:
The patent applies universality by enabling a single pair of electrodes to control multiple liquid crystal layers with different threshold voltages. The first electrode pair can selectively activate different liquid crystal layers by applying voltages within specific ranges, allowing one electrode structure to perform the function that previously required separate electrodes for each layer, thus reducing device complexity while maintaining color display performance
Solution Approach 2:
The patent utilizes parameter changes by exploiting the difference in threshold voltages between liquid crystal compositions. By carefully selecting and controlling the voltage magnitude and frequency, the system can selectively switch between different liquid crystal layers. The first voltage applies to a first liquid crystal layer with a first threshold voltage, while the second voltage applies to a second liquid crystal layer with a second threshold voltage, enabling independent control through parameter variation rather than structural complexity
2Device complexity
If dual frequency addressable liquid crystal is used to address multiple layers with one pair of electrodes, then device complexity is reduced, but color reproduction range becomes narrow due to complimentary color relationship
Solution Approach 1:
The patent applies local quality by assigning different functional characteristics to different liquid crystal layers. Each liquid crystal layer is composed with specific dichroic dyes having different absorption wavelengths, creating localized color properties. The first liquid crystal layer contains a first dichroic dye with a first absorption wavelength, while the second liquid crystal layer contains a second dichroic dye with a second absorption wavelength, allowing each layer to contribute different colors to the overall display
3Device complexity
If conventional liquid crystal element with color filters is used, then structure is simple, but transmittance is decreased extremely resulting in extremely dark display
Solution Approach 1:
The patent applies color changes by using dichroic dyes that selectively absorb light at specific wavelengths. The dichroic dyes in the liquid crystal compositions change the color and light transmission properties of the liquid crystal layers dynamically. The first dichroic dye absorbs at a first wavelength and the second dichroic dye absorbs at a second wavelength, enabling color modulation without the need for fixed color filters, thus maintaining high transmittance and brightness
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
Enables high-quality color display with improved reflectance and memory properties, reducing the complexity of electrode structures and enhancing display performance with low power consumption.
Implementation Method 1
an electric field is applied, and alignment of the dichroic dye is changed along with the movement of the liquid crystals according to the electric field to change the light absorption state of the cell
Implementation Method 2
dual frequency addressable smectic liquid crystal compositions having different threshold voltages
Implementation Method 3
a dichroic dye is dissolved in the liquid crystal, an electric field is applied, and alignment of the dichroic dye is changed along with the movement of the liquid crystals according to the electric field to change the light absorption state of the cell
Implementation Method 4
the liquid crystal element can be utilized suitably as to a guest-host type liquid crystal element... suitable to reflection type display
Data Source
AI summary
A liquid crystal element in which a liquid crystal layer containing at least two types of dual frequency addressable smectic liquid crystal compositions having different threshold voltage are disposed between one pair of electrodes at least one of them being a transparent electrode.