Liquid Crystal Driving Method for Thick Cell Gap Back-Flow Suppression
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Solution Overview
Problem
Existing transmittance-variable devices using liquid crystal layers face challenges in suppressing back-flow phenomena and maintaining excellent response speeds and driving characteristics, especially when the cell gap becomes thick.
Innovation Solution
A method for driving an optical element with an active liquid crystal layer that includes applying a medium voltage before switching to a second state voltage, ensuring the first state voltage is lower than the second state voltage, and controlling the cell gap to minimize bulk liquid crystal effects, thereby suppressing back-flow and maintaining high transmittance and low transmittance states effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the cell gap of the liquid crystal layer is increased, then the device can accommodate thicker substrates and improve structural flexibility, but the back-flow phenomenon is enhanced and response speed deteriorates
Solution Approach 1:
The patent applies a preliminary action by introducing a pre-tilt alignment layer before the liquid crystal layer to pre-orient the liquid crystal molecules. This preliminary orientation setup counteracts the back-flow phenomenon that would otherwise occur in thick cell gaps, enabling the device to maintain fast response speeds while using thicker substrates for structural flexibility.
Solution Approach 2:
The patent changes the parameter of pre-tilt angle by introducing a pre-tilt alignment layer with a specific tilt angle (e.g., 10-80 degrees) to control the initial orientation of liquid crystal molecules. This parameter change allows the system to suppress back-flow in thick cell gaps while maintaining rapid response characteristics, resolving the contradiction between structural flexibility and response speed.
2Adaptability or versatility
If the cell gap of the liquid crystal layer is increased, then the device can accommodate thicker substrates, but the back-flow phenomenon is enhanced
Solution Approach 1:
The patent applies a preliminary action by introducing a pre-tilt alignment layer before the liquid crystal layer to pre-orient the liquid crystal molecules. This preliminary orientation setup counteracts the back-flow phenomenon that would otherwise occur in thick cell gaps, enabling the device to maintain fast response speeds while using thicker substrates for structural flexibility.
Solution Approach 2:
The patent changes the parameter of pre-tilt angle by introducing a pre-tilt alignment layer with a specific tilt angle (e.g., 10-80 degrees) to control the initial orientation of liquid crystal molecules. This parameter change allows the system to suppress back-flow in thick cell gaps while maintaining rapid response characteristics, resolving the contradiction between structural flexibility and response speed.
3Adaptability or versatility
If a thick liquid crystal layer is used, then the device can provide wider field of view and better viewing angles, but the response speed decreases
Solution Approach 1:
The patent applies a preliminary action by introducing a pre-tilt alignment layer before the liquid crystal layer to pre-orient the liquid crystal molecules. This preliminary orientation setup counteracts the back-flow phenomenon that would otherwise occur in thick cell gaps, enabling the device to maintain fast response speeds while using thicker substrates for structural flexibility.
Solution Approach 2:
The patent changes the parameter of pre-tilt angle by introducing a pre-tilt alignment layer with a specific tilt angle (e.g., 10-80 degrees) to control the initial orientation of liquid crystal molecules. This parameter change allows the system to suppress back-flow in thick cell gaps while maintaining rapid response characteristics, resolving the contradiction between structural flexibility and response speed.
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
The method effectively suppresses back-flow phenomena and ensures excellent response speeds and driving characteristics, enabling high transmittance and low transmittance states, even with thick cell gaps, suitable for various applications including augmented reality eyewear and architectural materials.
Implementation Method 1
adjusts the transmittance by adjusting the orientation of the dichroic dye guest in the GH cell, and for example, often adjusts the transmittance by switching the orientation of the liquid crystal compound between the vertically oriented state and the horizontally oriented state
Implementation Method 2
A transmittance-variable device using a so-called GH cell (guest host cell) applying a mixture of a liquid crystal host, which is mainly a liquid crystal compound, and a dichroic dye guest is known
Data Source
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AI summary
The present application relates to a driving method of an optical element, the optical element, a transmittance-variable device and a use thereof. In one example, the present application may provide a driving method suppressing a back-flow phenomenon caused by a bulk liquid crystal compound even when a cell gap of a liquid crystal layer becomes thick and ensuring excellent response speeds and driving characteristics.