可擦拭相變化超解析碟片的設計與製作

Abstract

可擦拭相變化碟片的記錄密度主要決定於雷射光點的大小，而光點的大小，則受限於雷射波長及物鏡(objective lens)的數值孔徑(numerical aperture, NA)。本文中所討論的可擦拭相變化超解析碟片(Erasable Phase-change Superresoultion optical disk)，採用不同於相變化碟片的結構，可以縮小光點檢出訊號的區域，達到超解析的效果。 文中，利用可相變化超解析的讀取原理，制定光學的讀取規格。依此規格，進行光學模擬，選出適合的碟片結構群。隨後進行熱學模擬，由碟片於讀寫時熱學上的要求，挑選EPSR的碟片結構並觀察其現象。最後，根據光碟測試機的規格，實際備製EPSR碟片，進行讀寫測試。實驗結果發現：碟片結構Substrate/ZnS-SiO2 (82nm)/Ge1Te7Sb4(3nm)/ZnS-SiO2(286nm)/Ge21 Te53 Sb26 (24nm)/ZnS-SiO2(30nm)/AI (90nm)的EPSR碟片，用脈衝讀取法讀取，可達到超解析的效果，其CNR值為32.7dB。

Recording density in optical recording media is mainly determined by the laser spot size on the media. The Erasable Phase-change Superresolution optical diskk (EPSR) reported in the paper are designed to be in a different structure from the normal phase change disk to achieve optical superresolution. First of all, we defined the specifications of reading and writing according to the requirements of EPSR.By simulating the reflectivity of the disk, suitable disk structures could be found. Thereafter, we proceeded the heat simulation and picked the suitable disk structure. Finally, EPSR was made and tested. We found that CNR of the EPSR disk of the structure: ZnS-SiO2 (82nm)/Ge1Te7Sb4(3nm)/ZnS-SiO2(286nm)/Ge21 Te53 Sb26 (24nm)/ZnS-SiO2(30nm)/AI (90nm) could reach 32.7dB using pulse-read scheme.