基於圖案變化之平面傾斜檢測應用在同軸式全像資料儲存系統

Abstract

光碟片在轉動時，碟片震動會造成左右搖晃而有些微的傾斜。此時，光束與碟片的關係不再是垂直角度，由於布拉格條件的限制，使得資料頁無法準確的被儲存與讀取至全像片上。因此如何有效檢測出碟片傾斜的角度、方向便成為當前的研發課題。本文基於碟片傾斜對全像儲存系統的影響，提供一種新的檢測方法，利用記錄於資料點周圍的微型圖案偏移角度來估測實際光碟因轉動所傾斜的角度，透過計算圖案面積變化的大小，可檢測此平面的傾斜方位及角度，可取代原本系統中的PSD(position sensitive detector)，使得全像資料儲存系統精簡化。

In the rotating disk, the disk vibration causes irregular shaking which made the disk slightly inclined. When disk inclination occurs, the angle between the reference beam and the media is changed, thus the data cannot be recorded with a right angle or another data page is retrieved. The data retrieval in the holographic data storage system is very sensitive to the inclined disturbance due to the Bragg condition. Therefore, how to effectively detect the angle and direction of the disk tilt became the subject of current research topics. This paper is based on the disk inclination effect towards the holographic data storage system, and provides a new detection method which locates the micro patterns that are recorded around the data pattern. The new method estimates the direction and the angle of the disk plane inclination by calculating the area variation of the micro patterns. It could simplify and replace the usage of the position sensitive detector of the original system that has resulted in the collinear holographic data storage system.