2024

Vol.30 No.4

Editorial Office

Review

  • Journal of the Microelectronics and Packaging Society
  • Volume 30(3); 2023
  • Article

Review

Journal of the Microelectronics and Packaging Society 2023;30(3):78-82. Published online: Nov, 9, 2023

Fabrication of 3-Step Light Transmittance-variable Smart Windows based on λ/2 Retardation Film

  • Il-Gu Kim, Ho-Chang Yang, Young-Min Park, Yo-Han Suh, Young Kyu Hong, and Seung Hyun Lee
    Smart Electronics Research Center, Korea Electronics Technology Institute 111, Ballyong-ro, Deokjin-gu, Jeonju-si, Jeollabuk-do 54853, Korea
Corresponding author E-mail: leesh0512@keti.re.kr
Abstract

A fabrication of smart windows with controllable visible light transmittance in three steps by using λ/2 retardation films based on a reactive mesogen (RM) material and polarizing films is demonstrated. The phase retardation films with a Δn·d value of λ/2 (λ: wavelength) convert the direction of a traveling light to the optical axis of the film symmetrically. In this work, the retardation characteristics according to the RM thickness were evaluated and henceλ/2 phase retardation film can be fabricated. The phase retardation film with Δn·d of 276.1 nm, which is close to λ/2 (=275 nm @550 nm), was fabricated. The light transmittance of a smart window with the structure of (polarizing film)/(glass)/(alignment layer)/(λ/2 retardation film) was measured in the transmission mode, half mode and blocking mode. The evaluation results show that the transmittance of the smart window can be controlled in three steps with 35.8%, 27.8%, and 18.2% at each mode, respectively. In addition, by fabricating a smart window with a size of 150×200 mm2, the feasibility of use in various fields such as buildings and automobiles was verified.

Keywords Smart window, Phase retardation, Retarder, Reactive mesogen, Transmittance-variable

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