• Title/Summary/Keyword: Infrared reflective coating

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A Study on the Transmittance, Heat-Resistance, and Mechanical Properties of SiO2, TiO2 Anti-Reflective Single Layers Deposited on Sapphire Substrate by MOCVD (금속유기화학증착법으로 사파이어 기판에 증착된 단층 SiO2, TiO2 저반사막의 광 투과율, 내열성, 기계적 특성에 관한 연구)

  • Shim, Gyu-In;Eom, Hyengwoo;Kang, Hyung;Choi, Se-Young
    • Journal of the Korea Institute of Military Science and Technology
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    • v.17 no.5
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    • pp.672-679
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    • 2014
  • To improve sensing capability of infrared, heat-resistance and mechanical properties, the $SiO_2$ and $TiO_2$ anti-reflective layers were coated on sapphire substrate by MOCVD. The standard wavelength was 4,600nm, and the thickness of anti-reflective layers were 379 and 758nm in case of ${\lambda}/4$ and ${\lambda}/2$ of incident angle($65^{\circ}$), respectively. The $SiO_2$ and $TiO_2$ anti-reflective layers were coated 12.6 and 9.7nm/min of deposition rates by increasing oxygen pressure to set the ideal refractive index of 1.283. In case of $SiO_2({\lambda}/2)$ coating, the transmittance increased from 55.0 to 62.7%. The transmittance of $TiO_2({\lambda}/2)$ anti-reflective layer also increased from 55.0 to 64.8%. The flexural strength of $SiO_2({\lambda}/2)$ and $TiO_2({\lambda}/2)$ layer coated sapphire increased from 337.8 to 362.9 and 371.8MPa, respectively. The flexural strength at $500^{\circ}C$ of these materials also increased respectively to 304.5, 358.2MPa from 265.9MPa. From these results, we confirmed these materials can be used as transmission window of infrared light.

A Design of Mid-wave Infrared Integral Catadioptric Optical System with Wide FOV

  • Yu, Lin Yao;Jia, Hong Guang;Wei, Qun;Jiang, Hu Hai;Zhang, Tian Yi;Wang, Chao
    • Journal of the Optical Society of Korea
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    • v.17 no.2
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    • pp.142-147
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    • 2013
  • In order to deduce the difficulty of fixing the Ritchey-Chretien (R-C) dual reflective optical system and enhance the stability of the secondary mirror, a compact integral structure is presented here composed of two transmitting and two reflective aspheric surfaces. The four surfaces were manufactured from a single germanium lens and integrated together. The two reflective surfaces formed by coating the inner reflecting films were assembled in one lens. It makes the installation of the two mirrors easier and the structure of the secondary mirror more stable. A design of mid-wave infrared (MWIR) compact imaging system is presented with a spectral range chosen as $3.7-4.8{\mu}m$. The effective focal length is f=90 mm. The field of view (FOV) for the lens is $4.88^{\circ}$. It has good imaging capability with Modulation Transfer Function (MTF) of all field of view more than 0.55 close to the diffraction limitation. Outdoor experiments were carried out and it is shown that the integral catadioptric optical system performs well on imaging.

Preparation of Fe4[Fe(CN)6]3 Coated on Mica or TiO2/Mica for Infrared Reflective Blue Pigments and Isolation-heat Properties of These Paints (Fe4[Fe(CN)6]3가 코팅된 Mica 또는 TiO2/Mica 적외선 반사용 청색안료 제조 및 이 도료의 차열 특성 평가)

  • Jung, Ha-Young;Kim, Dae Sung;Lee, Hyun-Jin;Lee, Seung-Ho;Lim, Hyung Mi;Choi, Byung-Ki;Kang, Kwang-Jung;Choi, Jin-Sub
    • Korean Journal of Materials Research
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    • v.23 no.12
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    • pp.672-679
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    • 2013
  • $Fe_4[Fe(CN)_6]_3$ coated on a mica or $TiO_2$/mica surface as infrared reflective blue pigment was prepared by a hydrothermal method. $Fe_4[Fe(CN)_6]_3$, used as coloring agent, was uniformly coated on mica or $TiO_2$/mica under the optimized condition of a 1.2 : 1 weight ratio between iron(III) chloride hexahydrate and potassium ferrocyanidetrihydrate at the initial pH level of 4.5 at $70^{\circ}C$. The infrared (IR)-reflective pigments were characterized by SEM, Zeta-potenial, FT-IR, and UV-VIS NIR spectrophotometry. Especially the CIE color coordinate and total solar reflectance(TSR) properties of the pigments were investigated in relation to variation of the coating and coated substrate thicknesses. Isolation-heat paint was prepared with 20 wt% blue pigments fully dispersed in acryl-urethane resin and several additives to coat the film uniformly. The films were also measured with CIE color coordinate, TSR, and the surface temperature was recorded by an isolation-heat measuring system. The pigments and films of $Fe_4[Fe(CN)_6]_3$ coated on mica and $TiO_2$/mica showed high TSR values compared with the TSR value of $Fe_4[Fe(CN)_6]_3$ itself. According to the increase of TSR value, the property of isolation-heat is effective. To realize the optimal blue color, we applied the the pigment to $TiO_2$ coated mica(TM(b)) which has blueish interference color. The pigment of $Fe_4[Fe(CN)_6]_3$ coated on TM(b) shows a strong blue color compared with that of $Fe_4[Fe(CN)_6]_3$ coated on $TiO_2$/Mmca(TM(w)), which has a whitish interference color.

Development of IR Reflective Cool Pigment and Paint (차열도료용 Cool Pigment 및 Paint 개발)

  • Kwon, Myon-Joo;Do, Young-Woong;Ha, Jin-Wook
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.8
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    • pp.3800-3805
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    • 2012
  • Infrared(IR) reflective black cool pigment and paint which is used for interior/exterior materials(IR reflectance >30%) to prevent heat island effect and to increase energy efficiency were studied. Cool pigment was synthesized using mixture of $Fe_2O_3$ and $Cr_2O_3$ with calcination from 900 to $1,200^{\circ}C$. Cool paint was prepared by formulation of cool pigment, acrylic resins, and other additives. Results showed that optimum color fixation of pigment obtained by mole ratio of Fe to Cr was 0.9 with calcination temperature at $1,000^{\circ}C$. The cool paint formulated by 20% pigment and 1.5% dispersive additive with $125{\mu}m$ thickness of coated layer showed optimum IR reflectance. Temperature difference on surface between cool paint and ordinary paint(STD) was $36.5^{\circ}C$ and IR reflectance(TSR) was 39.3% at wavelength from 700 to 2,500nm. And color change was not detected during 500hrs weathering test.

The development of highly functional paints improving NIR reflectance by investigating silica particles size for pigment mixing (안료배합용 실리카 입자사이즈에 따른 근적외선 반사율을 향상시킨 고기능성 도료 제조)

  • Eunseok Woo;Yunseok Noh;Jinho Lee;Yong-Wook Choi;Bora Kim
    • Journal of the Korean institute of surface engineering
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    • v.57 no.2
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    • pp.98-104
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    • 2024
  • In order to overcome the urban heat island effect, highly functional paint is attracting attention as a promising means by shielding heat on the structure (building) surface. When a paint was prepared containing nano-sized silica particles, the heat-insulating performance was relatively higher than that of paints with other sizes. In addition, developed paints showed enhanced properties such as chemical resistance and abrasion resistance test because of the presence of nano-sized silica included in functional paint.

Characteristics of sub-80 nm three-layered film manufactured by continuous roll-to-roll processes (연속 롤투롤 공정을 이용한 80 나노 이하의 3층 구조 필름 제조 및 특성)

  • Nam Il Kim;Geug Tae Kim
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.33 no.5
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    • pp.191-195
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    • 2023
  • Three-layer nano-coated films in applications for the back cover of mobile cellular phones were prepared utilizing a roll-to-roll continuous process. By introducing a coating layer with a ceramic/metal/ceramic three-layer structure, the inherent reflective properties of the metals were maintained while electrically insulating properties were maintained. The thickness of the composite coating layer on a large area PET film with a length of 1,500 nm and width of 500 nm was less than 60 nm, and a uniform thickness was maintained in all areas. The transmittance according to the wavelength range (240~1600 nm) of the nanocoating film gradually increases as the wavelength increases, and is about 48 % at 1,000 nm, which is within the infrared region, and about 35.5 % at 550 nm, which is within the visible region. These results meet the required level of coated backcover (< 40 %).

Effects of Surface Homogeneity on Optical Properties of Sputter-deposited AlTiO Selective Transmitting Layers (스퍼터 증착으로 형성된 AlTiO 선택적 투과막의 표면 균질성에 따른 광학적 특성)

  • Jeong, So-Un;Lim, Jung-Wook;Lee, Seung-Yun
    • Journal of the Korean Vacuum Society
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    • v.21 no.1
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    • pp.22-28
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    • 2012
  • Transparent dye-sensitized solar cells have been widely investigated for the application to building integrated photovoltaic system. Thin film Si-based solar cells are emerging as a substitute for the dye-sensitized solar cells because their merits of well-established manufacturing processes. Since the selective transmitting layer transmits visible light and reflects infrared light, the solar cell efficiency increases with the introduction of the selective transmitting layer. In this work, AlTiO thin films were grown as the selective transmitting layer by cost-effective sputter deposition and their transmittances were improved by controlling deposition parameters.

Sodium titanate as an infrared reflective material for cool roof application

  • Ullah, Mahboob;Kim, Hee Jung;Heo, Jae Gu;Roh, Dong Kyu;Kim, Dae-Sung
    • Journal of Ceramic Processing Research
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    • v.20 no.spc1
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    • pp.86-91
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    • 2019
  • A solid-state route was used to prepare sodium titanium oxide (NTO, Na2Ti3O7) as a solar heat protecting material with an impressive solar reflectance (TSR = 94.3%) using a high refractive index rutile TiO2. The solar reflectance of the synthesized NTO was measured using UV-Vis-NIR spectrophotometer. Solar reflectance property of the synthesized compound depends on the calcination temperature. The solar reflectance property of the synthesized NTO powder was compared with commercial rutile TiO2. The compound synthesized at 900 ℃ for 24 hrs had remarkable solar reflectance 94.3% than that calcined below 900 ℃. Crystalline nature, structural property, morphology and optical properties of NTO powders were characterized and analyzed using XRD, FE-SEM, EDS and UV-Vis-NIR spectrophotometer. From the results, we guessed that NTO would be a suitable "solar heat protecting candidate" for energy-saving applications in coating industries.