Electro-Optical Blocking Device Dual Attenuation Mode
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Solution Overview
Problem
Current electro-optical shutter devices, particularly in active 3D glasses, face challenges in achieving precise and ultra-fast light attenuation with high transmission rates and low ghosting, due to limitations in material compatibility, high switching voltages, and long switching times, as well as the complexity of mixing dichroic and cholesteric liquid crystals.
Innovation Solution
The solution involves a dual-cell configuration with separate absorption and diffusion cells, each with its own switching mechanism, allowing for independent control and optimization of optical properties, reducing cell thickness and voltage requirements, and minimizing demixing risks, while enabling dual attenuation modes and improved electro-optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high concentration of dichroic dopant and thick cell are used to achieve high absorption rate, then the blocking state performance is improved, but the switching time increases and demixing risk increases
Solution Approach 1:
The invention divides the single optical cell into two separate cells: a first optical cell containing dichroic liquid crystal for absorption, and a second optical cell containing cholesteric liquid crystal for scattering. This segmentation allows each cell to be optimized independently - the first cell can use high dopant concentration for strong absorption without excessive thickness, while the second cell provides additional attenuation through scattering, thereby reducing overall switching time and demixing risk while maintaining blocking performance.
2Reliability
If a single optical cell with high dichroic dopant concentration is used to achieve strong attenuation, then the blocking state is improved, but the transparent state transmission rate decreases and ghosting increases
Solution Approach 1:
The invention separates the attenuation function into two distinct mechanisms in two separate cells: the first cell uses dichroic absorption (molecular alignment-based light absorption), and the second cell uses cholesteric scattering (helical structure-based light scattering). This segmentation enables independent optimization - the first cell can provide strong attenuation in blocking state while maintaining high transmission in transparent state, and the second cell enhances attenuation contrast through scattering, together achieving both high transmission and low ghosting simultaneously.
3Device complexity
If dichroic and cholesteric liquid crystals are mixed in a single cell to achieve dual attenuation modes, then the device complexity is reduced, but material compatibility and demixing become problematic
Solution Approach 1:
Instead of mixing dichroic and cholesteric liquid crystals in a single cell, the invention segments them into two separate cells with distinct functions. The first cell contains only dichroic liquid crystal for absorption-based attenuation, while the second cell contains only cholesteric liquid crystal for scattering-based attenuation. This segmentation eliminates material compatibility and demixing issues while maintaining dual attenuation modes, and each cell can be independently optimized without compositional constraints.
4Reliability
If crossed polarizers are used to create dynamic shutters to achieve good ghosting immunity, then the blocking state is improved, but the transmission rate is limited and attenuation contrast is insufficient
Solution Approach 1:
The invention replaces the traditional crossed polarizer system with an electro-optical system using liquid crystal cells. The first cell uses dichroic liquid crystal whose absorption properties change with applied voltage, and the second cell uses cholesteric liquid crystal whose scattering properties change with applied voltage. This substitution eliminates the inherent 50% light loss of crossed polarizers, enabling high transmission rates in transparent state while maintaining strong attenuation in blocking state through electro-optical control, thereby achieving both high transmission and good ghosting immunity.
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 configuration achieves faster switching times, lower voltage requirements, and enhanced attenuation contrast, effectively addressing the limitations of single-cell devices and improving material compatibility, resulting in improved electro-optical performance and reduced ghosting.
Implementation Method 1
a dichroic guest material which absorbs light in a given absorption range
Implementation Method 2
a cholesteric liquid crystal material having a phase with a focal conical molecular orientation
Implementation Method 3
whose optical properties can be modified by applying an electric field to them
Data Source
Figure 1A~1B
Figure 2A
Figure 2B
AI summary
The invention relates to an electro-optical blocking device (100) comprising an assembly of at least two superimposed optical cells, comprising: at least one light absorption cell (110) comprising a layer (115) of a mixture consisting of a host material based on liquid crystal and at least one dichroic guest material; and at least one light diffusion cell (120) comprising a layer (125) of a cholesteric liquid crystal material.