Electrically Switchable and Permanently Stable Light Scattering Modes by Dynamic Fingerprint Chiral Textures

Cheng, Kuo-Hsing; Lee, Po Yi; Qasim, Malik M.; Liu, Cheng-Kai; Cheng, Wei-Hsiang; Wilkinson, Timothy D.

doi:10.1021/acsami.5b12854

Cited by 30 publications

(10 citation statements)

References 29 publications

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“…The calculation speed is further increased, and the energy consumption is further decreased. When reconfigurable optical elements, such as those based on a liquid crystal modulator 43 – 45 or metasurfaces 46 , 47 , are incorporated into LOEN, the convolution kernels can be programmable. Thus, the convolution in the space and time domains can be realized 48 , 49 , while the structure can be transferred to other tasks.…”

Section: Discussionmentioning

confidence: 99%

LOEN: Lensless opto-electronic neural network empowered machine vision

Shi

Huang

et al. 2022

Light Sci Appl

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Machine vision faces bottlenecks in computing power consumption and large amounts of data. Although opto-electronic hybrid neural networks can provide assistance, they usually have complex structures and are highly dependent on a coherent light source; therefore, they are not suitable for natural lighting environment applications. In this paper, we propose a novel lensless opto-electronic neural network architecture for machine vision applications. The architecture optimizes a passive optical mask by means of a task-oriented neural network design, performs the optical convolution calculation operation using the lensless architecture, and reduces the device size and amount of calculation required. We demonstrate the performance of handwritten digit classification tasks with a multiple-kernel mask in which accuracies of as much as 97.21% were achieved. Furthermore, we optimize a large-kernel mask to perform optical encryption for privacy-protecting face recognition, thereby obtaining the same recognition accuracy performance as no-encryption methods. Compared with the random MLS pattern, the recognition accuracy is improved by more than 6%.

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Section: Discussionmentioning

confidence: 99%

LOEN: Lensless opto-electronic neural network empowered machine vision

Shi

Huang

et al. 2022

Light Sci Appl

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“…Among them, EHD devices do not need specific electrodes, have a simple structure, are easy to control, and have excellent electro-optical performance. Based on the frequency characteristics of the EHD effect, many steady-state negative CLC devices have been suggested. − By controlling the electric field, the negative CLC can switch between the planar state, the dynamic scattering (DS) state, and the FC state. The stable planar state and FC state can provide the device with a transparent state and a light-scattering state without the need to maintain the electric field.…”

Section: Introductionmentioning

confidence: 99%

Colorable Light-Scattering Device Based on Polymer-Stabilized Ion-Doped Cholesteric Liquid Crystal and an Electrochromatic Layer

Guo

Zhang

et al. 2023

ACS Appl. Mater. Interfaces

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Bistable polymer-stabilized cholesteric liquid crystal (LC) devices have been extensively researched due to their energysaving benefits. Compared to devices with merely transparent and light-scattering states, LC devices with controlled light absorption or changeable color functions are unquestionably more intriguing. In this paper, a polymer-stabilized ion-doped cholesteric LC and an electrochromic layer are used to fabricate a colorable device which can show four operating states: transparent, light-scattering, colored transparent, and colored light-scattering. The working principle and fabrication strategy are explained in detail. Based on the dielectric response of LC, the electrohydrodynamic effect of ion-doped LC, and the redox reaction of electrochromic materials, the transparent or light-scattering state and the colored or colorless state of the device can be regulated by controlling the alternating frequency and the direction of the electric field. The display performance related to the monomer, chiral dopant, and electrochromic layer is investigated. The content of monomer and chiral dopant affects the polymer network and pitch of cholesteric LC, which then affects the driving voltages and contrast ratio. The thickness of the electrochromic layer has a significant impact on the transmittance of the device's coloring and fading states. The sample with excellent operating states is obtained by optimizing the material and the construction, which can be widely applied in smart windows and energy-saving display devices.

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“…In recent researches, a cholesteric liquid crystal light shutter has been developed. This shutter has a cholesteric liquid crystal with negative dielectric anisotropy; it is switched by a high-frequency voltage pulse switched into the transparent planar state and by a low-frequency voltage pulse back into the scattering focal conic state [21][22][23]. This operation increases the tolerance of the CLC for d/p and boundary conditions, and a high-frequency voltage can be used to obtain good planar states even when the cell gap is large or pitch is short (large d/p).…”

Section: Introductionmentioning

confidence: 99%

Smart Window with Active-Passive Hybrid Control

et al. 2020

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Dimming and scattering control are two of the major features of smart windows, which provide adjustable sunlight intensity and protect the privacy of people in a building. A hybrid photo- and electrical-controllable smart window that exploits salt and photochromic dichroic dye-doped cholesteric liquid crystal was developed. The photochromic dichroic dye causes a change in transmittance from high to low upon exposure to sunlight. When the light source is removed, the smart window returns from colored to colorless. The salt-doped cholesteric liquid crystal can be bi-stably switched from transparent into the scattering state by a low-frequency voltage pulse and switched back to its transparent state by a high-frequency voltage pulse. In its operating mode, an LC smart window can be passively dimmed by sunlight and the haze can be actively controlled by applying an electrical field to it; it therefore exhibits four optical states—transparent, scattering, dark clear, and dark opaque. Each state is stable in the absence of an applied voltage. This smart window can automatically dim when the sunlight gets stronger, and according to user needs, actively adjust the haze to achieve privacy protection.

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Electrically Switchable and Permanently Stable Light Scattering Modes by Dynamic Fingerprint Chiral Textures

Cited by 30 publications

References 29 publications

LOEN: Lensless opto-electronic neural network empowered machine vision

LOEN: Lensless opto-electronic neural network empowered machine vision

Colorable Light-Scattering Device Based on Polymer-Stabilized Ion-Doped Cholesteric Liquid Crystal and an Electrochromatic Layer

Smart Window with Active-Passive Hybrid Control

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