Optical Filter with Large Angular Dependence of Transmittance Using Liquid Crystal Devices

Takatoh, Kohki; Ito, Masahiro; Saito, Suguru; Takagi, Yuuta

doi:10.3390/cryst11101199

Cited by 3 publications

(14 citation statements)

References 8 publications

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“…In both Figure 13 and Figure 14 , the maximum values can be observed around −20°. This phenomenon could be observed for the devices using LCDs [ 4 ]. With a large incident angle, the transmittance could decrease as the optical path extends.…”

Section: Resultsmentioning

confidence: 84%

“…The authors proposed optical devices using liquid crystal devices (LCDs) with asymmetric transmittance [ 4 , 5 ]. For these devices, hybrid alignment nematic (HAN) LCDs [ 6 , 7 , 8 , 9 , 10 , 11 , 12 ] and LCDs of high pretilt parallel alignment with dichroic dye were used.…”

Section: Introductionmentioning

confidence: 99%

“…The polar angle of the dye molecules changes through the LC layer. The average polar angle of the molecules is shown [ 4 ].…”

Section: Introductionmentioning

confidence: 99%

“…Figure 4 shows the mechanism realizing the dependence of the transmittance on the incident angle when using the structure shown in Figure 3 [ 4 ]. The incident light parallel to the dye’s molecular axis passes through the films with little absorption.…”

Section: Introductionmentioning

confidence: 99%

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Optical Filters with Asymmetric Transmittance Depending on the Incident Angle, Produced Using Liquid Crystalline Ink (Louver LC Filters)

2023

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In many situations in everyday life, sunlight levels need to be reduced. Optical filters with asymmetric transmittance dependent on the incident angle would be useful for sunglasses and vehicle or architectural windows, among others. Herein, we realized the production of optical filters, called “louver filters”, comprising HAN-type LC film produced using liquid crystalline ink with dichroic dyes. For the formation of the HAN-type LC film, the liquid crystalline ink was aligned on a rubbed polyimide layer and polymerized by UV irradiation. Two kinds of filters are proposed: one is a filter composed of HAN-type LC film and a polarizer, and the other is composed of two HAN-LC films with a half-wave plate between them. The dependence of the asymmetric transmittance on the incident angle was confirmed for these filters. The dependence changed depending on the pretilt angle of the alignment layers. Photographs taken with the optical filters displayed their effectiveness.

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Section: Resultsmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

“…The polar angle of the dye molecules changes through the LC layer. The average polar angle of the molecules is shown [ 4 ].…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Optical Filters with Asymmetric Transmittance Depending on the Incident Angle, Produced Using Liquid Crystalline Ink (Louver LC Filters)

2023

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“…Takatoh et al proposed a new type of optical device with variable transmittance based on the incident angle direction. ese devices consist of two liquid crystal devices (LCDs) with a half-wave plate between them, a wide range of transmittances was obtained because no polarizer was used [14]. Yoon et al [15] proposed a homogeneously aligned liquid crystal device in which the liquid crystal director does tilt as well as twist deformation in a confined area by both vertical-and fringe-electric fields, exhibiting about two times faster decay response time than that of conventional FFS mode with suppressed luminance in the upward direction.…”

Section: Related Improvements In Human-machine Interface Design In Mo...mentioning

confidence: 99%

A Study of Trends on Human-Machine Interface Design in Modern Vehicles

Jianan

Aziz

Salleh

2022

Scientific Programming

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This study aims to analyze the development trends of intelligent device interface improvements, specifically the car dashboards, by applying liquid crystal display technology. The methodology used in this study is mainly a comparison and analysis of the improvements that have been made. The objects in the study were several old version dashboards display instruments that were compared against the improved version of the LCDs. This paper analyses the requirements of car operators, with various proficiency for drivers’ information, in enhancing the modern car dashboards displays. Besides, this study further delves into ways through which instrument interface intelligently can be improved to adapt effectively to all kinds of drivers. This study also touches on an analytical view of information targeting drivers. This is a scientific technique to determine the extent of information needed from drivers in different circumstances by having precise or averaged information about the drivers; it is easier to integrate this information into the human interface that helps in these modern car operations. The results of the study show that the current LCD Dashboards are valuable, accurate, precise user friendly, and improved with integrated ICT pieces of equipment. This makes them much better than the older traditional systems of the car dashboards.

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Angular Dependence of Guest–Host Liquid Crystal Devices with High Pretilt Angle Using Mixture of Vertical and Horizontal Alignment Materials

et al. 2023

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To date, devices exhibiting incidence-angle-dependent transmittance have been fabricated by imparting an angle to a bulk liquid crystal (LC) by aligning the LC in the vicinity of one substrate horizontally (with respect to the substrate) while aligning the LC in the vicinity of another substrate vertically. Another approach has been to control LC angles near substrates by blending or layering horizontal and vertical alignment films. In this study, we control LC angles near substrates by controlling the pretilt angles of blended alignment films; for specific angles, we use dichroic dyes to characterize the incidence angle dependence of these LC devices. Using a guest/host LC device with a pretilt angle near 45°, we successfully construct an LC element with a transmittance peak near a polar angle of 45°.

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Optical Filter with Large Angular Dependence of Transmittance Using Liquid Crystal Devices

Cited by 3 publications

References 8 publications

Optical Filters with Asymmetric Transmittance Depending on the Incident Angle, Produced Using Liquid Crystalline Ink (Louver LC Filters)

Optical Filters with Asymmetric Transmittance Depending on the Incident Angle, Produced Using Liquid Crystalline Ink (Louver LC Filters)

A Study of Trends on Human-Machine Interface Design in Modern Vehicles

Angular Dependence of Guest–Host Liquid Crystal Devices with High Pretilt Angle Using Mixture of Vertical and Horizontal Alignment Materials

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