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Single-Particle Cryo-EM Data Collection with Stage Tilt using Leginon
Published on: July 1, 2022
Michinori Honma1, Toshiaki Nose, Satoshi Yanase
1Department of Electronics and Information Systems, Faculty of Systems Science and Technology, Akita Prefectural University, Yurihonjo, Akita, Japan. mhonma@akita-pu.ac.jp
This study introduces a new method to control how liquid crystals align on rough surfaces. By using a tiny stylus to rub a special film, the researchers achieved smooth alignment of the liquid crystal molecules. This approach was used to create lenses that can change focus by adjusting the voltage. The lenses include both cylindrical and rectangular shapes. The study found that using a quadratic pattern for the rubbing process helps reduce optical distortions. The results suggest that this method can be used to make tunable lenses with improved performance.
Area of Science:
Background:
Optical systems often require dynamic control of focal length. Traditional lenses lack this adaptability. Liquid crystal (LC) lenses offer a solution by adjusting molecular alignment. Prior research has shown that LC alignment can be manipulated through surface treatments. However, achieving uniform director distributions remains a challenge. Surface roughness can disrupt LC orientation. This gap motivated the development of new alignment methods. No prior work had resolved the issue of maintaining smooth director distributions on rough surfaces. This study addresses that limitation.
Purpose Of The Study:
The aim is to develop a method for controlling LC pretilt angles on rough surfaces. This method uses a stylus to rub polyimide films. The goal is to achieve smooth LC director distributions. The study also applies this method to variable-focus lenses. The focus is on cylindrical and rectangular lens designs. The motivation is to enable tunable optical systems. The approach is to use spatially distributed tilt angles. This could lead to improved lens performance.
Main Methods:
The method involves rubbing polyimide films with a stylus. The rubbing density is controlled to adjust pretilt angles. A side-chain type polyimide film is used for homeotropic alignment. The surface is treated to induce LC director orientation. The rubbing pitch is adjusted to minimize aberration. The distribution is quadratic in shape. This is applied to cylindrical and rectangular LC lenses. The focal length is measured under varying voltages.
Main Results:
Smooth LC director distributions were achieved on rough surfaces. The pretilt angle control was successful with the stylus method. The rubbing pitch distribution was quadratic for minimal aberration. Variable focusing was demonstrated in rectangular lenses. The focal length changed with applied voltage. Molecular reorientation explained the voltage dependence. The LC alignment remained stable despite surface roughness. These results suggest improved lens performance is achievable.
Conclusions:
The proposed method successfully controls LC pretilt angles on rough surfaces. Smooth director distributions were achieved despite surface irregularities. The quadratic rubbing pitch reduced optical aberration. Variable focusing was demonstrated in rectangular lenses. Voltage dependence of focal length was explained by molecular reorientation. The method is applicable to cylindrical and rectangular lens designs. These findings suggest the approach is effective for tunable optics. The results align with the authors' stated goals.
The study successfully achieved smooth liquid crystal director distributions on rough surfaces using a stylus-based rubbing method.
The method involves rubbing a side-chain polyimide film with a stylus to control surface pretilt angles for homeotropic alignment.
A quadratic distribution of the rubbing pitch minimizes optical aberration in liquid crystal lenses.
Voltage changes the focal length by inducing liquid crystal molecular reorientation.
Both cylindrical and rectangular liquid crystal lenses were tested for variable focusing.
The results suggest that rough surface orientation can be used to create tunable liquid crystal lenses with smooth director distributions.