• Proceedings of the Optical Society of Korea Conference
• /
• 2000.02a
• /
• pp.170-171
• /
• 2000

현재 사용하고 있는 디스플레이 장치에는 표면에 무반사(antireflection), 무정전(antistatic) 코팅이 되어 있다. 이것은 전기적으로 음극선관(CRT)에서 발생되는 전자에 의해 표면에 생기는 전하의 적층을 제거하여 정전기를 방지하고 인체에 유해한 전자기파를 차단하는 무정전 기능과, 광학적으로 디스플레이 장치 표면에서 외부의 조명등과 같은 빛의 반사를 줄여 내부에서 나오는 정보(빛)가 보다 더 눈에 선명하게 들어오도록 해준다. 무반사 무정전 코팅의 투과 전도층으로는 비저항값이 낮고 가시광선 영역에서 굴절률이 높고 흡수가 적어 투과율이 높은 indium tin oxide(ITO)가 널리 연구, 사용되어 왔다. 이러한 ITO 박막 대신에 TiN 박막을 사용하여 그 위에 유전체층을 증착하여 단 2층으로 무반사 무정전 코팅을 제작 할 수 있다. TiN 박막은 절삭공구 등의 표면에 마모방지용 코팅재료로서 사용되고 있고, 부착력이 우수하며 화학적 안정성이 뛰어나 수명이 긴 박막을 제작 할 수 있는 장점을 가지고 있다. 또한 가시광선 영역에서 흡수로 인해 투과율이 ITO에 비해 상대적으로 낮지만 이점이 오히려 명도대비(contrast)의 향상을 가져온다. (중략)

• Journal of the Optical Society of Korea
• /
• v.4 no.2
• /
• pp.86-88
• /
• 2000

A sequence of functions are examined for the gradient-index AR thin film between two dielectric media and are used as the starting profiles in optimization to improve AR performance. Sinusoidal functions were quite efficient to use as components of the index change in the optimization. It is shown that there exist a number of gradient-index profiles which exhibit excellent AR-performance after control of the gradient-index profiles.

• Journal of the Optical Society of Korea
• /
• v.17 no.1
• /
• pp.1-4
• /
• 2013

For the conventionally polished fused silica substrate, an around 100 nm depth redeposition polishing layer was formed on the top of surface. Polishing compounds, densely embedded in the redeposition polishing layer were the dominant factor that limited the laser induced damage threshold (LIDT) of transmission elements in nanosecond laser systems. Chemical etching, super-precise polishing and ion beam etching were employed in different ways to eliminate these absorbers from the substrate. After that, Antireflection (AR) coatings were deposited on these substrates in the same batch and then tested by 1064 nm nano-pulse laser. It was found that among these techniques only the ion beam etching method, which can effectively remove the polishing compound and did not induce extra absorbers during the disposal process, can successfully improve the LIDT of AR coatings.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.18 no.12
• /
• pp.1935-1944
• /
• 1993

We calculate the optimum refractive index and thickness for a single layer antireflection coating as a function of active layer thickness of a laser diode using three different simplified numerical methods. The difference of the results using three methods comes from that of the effective refractive index of a laser used in three methods. We compare three simplified methods to an exact method to check the validity of the simplified methods. We conclude that the simplified method, choosing the effective index of a laser diode as a function of incidence angle of each plane wave composing of a guided mode agree well to an exact method for both TE and TM modes and the cases of strongly and weakly guiding.

• 한국태양에너지학회:학술대회논문집
• /
• 2009.11a
• /
• pp.367-370
• /
• 2009

It is important to reduce a reflection of light as a solar cell is device that directly converts the energy of solar radiation to electrical energy in oder to improve efficiency of solar cells. The antireflection coating has proven effective in providing substantial increase in solar cell efficiency. This paper investigates the formation of thin film PSi(porous silicon) layer on the surface of crystalline silicon substrates without other ARC(antirefiection coating) layers. On the other hand the formation of $SO_{2}/SiN_x$ ARC layers on the surface of crystalline silicon substrates. After that, the structure of PSi and $SO_2/SiN_x$ ARC was investigated by SEM and reflectance. The formation of PSi layer and $SO_{2}/SiN_x$ ARC layers on the textured silicon wafer result about 5% in the wavelength region from 0.4 to $1.0{\mu}m$. It is achieved on the textured crystalline silicon solar cell that each efficiency is 14.43%, 16.01%.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.55 no.12
• /
• pp.565-569
• /
• 2006

Plasma enhanced chemical vapor deposition(PECVD) is a well established technique for the deposition of hydrogenated film of silicon nitride (SiNx:H), which is commonly used as an antireflection coating as well as passivating layer in crystalline silicon solar cell. PECVD-SiNx:H films were investigated by varying the deposition and annealing conditions to optimize for the application in silicon solar cells. By varying the gas ratio (ammonia to silane), the silicon nitride films of refractive indices 1.85 - 2.45 were obtained. The film deposited at $450^{\circ}C$ showed the best carrier lifetime through the film deposition rate was not encouraging. The film deposited with the gas ratio of 0.57 showed the best carrier lifetime after annealing at a temperature of $800^{\circ}C$. The single crystalline silicon solar cells fabricated in conventional industrial production line applying the optimized film deposition and annealing conditions on large area substrate of size $125mm{\times}125mm$ (pseudo square) was found to have the conversion efficiencies as high as 17.05 %. Low cost and high efficiency silicon solar cells fabrication sequence has also been explained in this paper.

• Electrical & Electronic Materials
• /
• v.9 no.5
• /
• pp.498-505
• /
• 1996

In the present work, we have developed the simulator to optimize the process conditions of the AR(antireflection) and HR(high-reflection) coatings for the high power laser diode. The simulator can run on the PC. After making the simple optical model, we establish the Maxwell equations for the model by the operator conversion. By using the Mathematica, we derive a matrix for the multilayer system by applying the equations to the model and optimize the AR and HR coating process conditions by obtaining the reflection rate from the matrix. We also prove the validity of the simulator by comparing the simulation with the characteristics of the laser diode which is AR and HR coated according to the optimized conditions.

• Proceedings of the Polymer Society of Korea Conference
• /
• 2006.10a
• /
• pp.282-282
• /
• 2006

Nanoporous organosilicate thin films were realized by the microphase separation of pore generating components mixed with an organosilicate matrix. The refractive index of such nanoporous organosilicate films can be tuned in the range of $1.40{\sim}1.22$. With a nanoporous single layer with n ${\sim}1.225,\;99.85\;%$ transmittance in the visible range was achieved. In order to overcome the limitation on the narrow wavelength for high transmittance imposed by single nanoporous thin films, bilayer thin films with different reflectance for each layer were prepared by inserting high refractive index layer with a refractive index of 1.447. It is demonstrated that the novel broadband antireflection coating with improved transmittance can be easily achieved by the nanoporous bilayer thin films described in present study.

• ETRI Journal
• /
• v.24 no.5
• /
• pp.341-348
• /
• 2002

We propose an asymmetric sampled grating laser and a multi-wavelength laser array associated with it. Asymmetric sampling periods combined with an index shifter make it possible to use first order reflection for lasing operations. With the structure of our design, we achieved a simple fabrication procedure as well as a high yield without using complex and time-consuming e-beam lithography for multi-period gratings. We analyzed the effect of mirror coating by numerical analysis to improve single mode and power extraction performance. By using high reflection-antireflection coatings, we obtained high power extraction efficiency without degradation of the single mode property. For the multi-wavelength laser array, to gain wavelength control, we varied the sampling periods from one laser to an adjacent laser across the array. With this approach, we showed the feasibility of an array of up to 30 channels with 100 GHz wavelength spacing.

• Korean Journal of Optics and Photonics
• /
• v.9 no.5
• /
• pp.300-306
• /
• 1998

We have studied the optical effects in dielectric multilayer due to the interdiffusion formed during the deposition process. We suggest a numerical method to calculate the optical properties of periodical multilayer thin-films with gradient-index profiles. Using this method the spectral transmittance and reflectance were obtained for Fabry-Perot type filters, broad-band total reflectors and antireflection filters with interdiffusion layers. Interdiffusion reduced the spectral band width of high reflectance in total reflectors, and deteriorated the characteristics of multilayer AR-coatings leading to a large variation of reflectance if the number of the layers is large.