PDP 광학필터용 선택적 파장 흡수색소의 합성 및 물성에 관한 연구

Abstract

PDP 필터는 PDP TV의 광학특성을 향상시키고 근적외선 및 전자파 차폐기능을 갖는 PDP 핵심 광학 소재로서 색보정 기능, 전자파 차폐 기능 이외에도 Contrast 개선, 반사방지 등의 기능을 가지도록 고안되어 있다. PDP 필터 중 색보정 필름(Color Compensation Film)제조공정은 고분자(PMMA계)수지에 오렌지 광(λMAX=590nm)을 선택적으로 흡수하는 염료(상용명:Ne-cutting dye)를 혼합하여 기재인 고분자필름(PET)에 코팅하여 제조된다. PDP 필터의 광학특성은 방전가스(Ne gas)에 의해 발생되는 가시광 영역내의 파장(590nm)과 리모콘의 오작동을 유발시키는 근적외선 영역을 특수염료를 사용하여 필터링 하는 기능을 가진다. 오렌지 광을 선택적으로 흡수하는 염료 즉, Ne-cutting dye로 사용하기 위하여서는 최대 흡수파장(λMAX)이 585～605 nm의 영역을 크게 벗어나지 않는 동시에 물리·화학적 성질을 만족시키기 위한 적절한 염료구조 도입이 필요하며 PDP 필터용 색보정 필름에 대한 연구는 거의 보고 되지 않고 있다.3)～4) 따라서 본 연구의 목표는 PDP의 색순도 향상을 위하여 오렌지 광을 선택적으로 차단하는 염료의 합성 및 색보정 필름을 개발하는 것이며, 이를 위해서는 반치폭이 좁은 Cyanine계를 발색단으로 선정하고 서로 다른 헤테로환과 치환기 도입, 치환기의 대칭성 및 비대칭성을 갖는 염료를 설계하여 물리, 화학적 성질이 향상된 신규 Ne-cutting dye 합성하고 이를 색보정 필름에 응용하고자 한다.

The functional dye is a essential material in information industry : especially optical recording materials and optical filter for PDP display. The optical recording material was known as diphenylmethine, methine, polymethine, porphine, indanthrene, quinone, ditol and cyanine dye. The dyes for optical recording material must have specially the optical properties : Selective laser wavelength absorption ability, light-resistance, durability, and so on. The PDP display was used Neon cut off filter, selective wavelength 560～610nm. In this study, synthesized various cyanine dyes and researched the physical properties of optical recording materials and investigated characteristics of selective wavelength absorption with PDP optical filter. Cyanine dyes are researched widely as functional dyes. Especially, indolium cyanine dyes are expected from their superior solubility and their strong absorption in various wavelengths. Cyanine dyes have relatively good stability, high molar absorption coefficient(～10^(-5) M^(-1) cm^(-1)), medium fluorescence intensity, narrow spectrum width and the ability to form H- or J-aggregate. The maximum absorption wavelength of cyanine can be tuned precisely from Near-UV to near IR by chemical structural modification. With these unique photo-physical and photochemical properties, cyanine dyes are recently being used in many applications such as nonlinear optics, optical data storage, biomolecular labeling, dye laser, photo-refractive materials and photodynamic therapy. Therefore, this study was carried out to research the spectroscopic properties of cyanine dyes for PDP optical filter which lead to change middle-chain and indole. And then, the thirty-two cyanine dyes bearing ^(-)PF6, ^(-N)(SO₂CF₃)₂ and ^(-)C(CN)₃ are synthesized by ion-exchange with ^(-)I salts. The synthesized cyanine dyes were studied thermal property and compatibility. Spectroscopic properties of the cyanine dyes were measured with UV/Vis/NIR spectrophotometer(Shimadzu 3150PC) for characters of half band width, maximum absorption wavelength and shape of wavelength. In addition, we measure compatibility making PDP optical film. and differential Scanning Calorimeter was employed to measure durability for heating. The results were as follows. These cyanine dyes synthesized in above 70%, respectively. The synthesized cyanine dyes represented maximum absorption wavelength at near 544.5～662.0nm and had molar extinction coefficient above 8×10⁴. Particularly, cyanine #13 can make use of good material PDP optical filter. Cyanine dye bearing Nitro-group was red shift than cyanine dye without it ; about 20nm. The maximum absorption wavelength was red shift about 100nm with the increase of two methine groups such as cyanine #1(546.5nm), cyanine #4(642nm). The other hand, half band width of cyanine dyes decreased according to increase middle chains ; cyanine #1(53.5nm), cyanine #4(39nm). Melting point of cyanine dyes differed from salts and middle chain structure of dyes. It showed the best melting point cyanine dyes bearing ^(-C)(CN)₃ and ^(-)N(SO₂CF₃)₂ when they have forming middle chain without methyl and ethyl group such as cyanine #1, 5, 9, 10, 11, 12, 13. However, cyanine dyes with methyl and ethyl group at middle chain is stable to them bearing -PF6 and -C(CN)₃ salts. Cyanine dyes move to short-wavelength when they dissolve at polarity solvent.