Imaging formula and object - image scale formula of laser beam transferred by focus lens are deduced according to the abcd law of matrix optics , and the factors that effect on beam focus properties are analyzed based on these two formulas 根據矩陣光學變換的abcd定律,推導出激光束經過單聚焦鏡變換后的成像公式和物像比例公式,并在此基礎上討論光束質量和聚焦系統特性對光束聚焦性能的影響。
4 , single focuse the single head : is single for single laser head that panasonic lead off to adopt to focuse the double the laser beam for focusing ordering the project , he adopting the special whole synthesizing lens , passing lens in the center part ofly the focusing of formation cd the point , and pass the anastigmatic laser beam of part edge the formation the focusing of dvd the point , this kind of construction because of have no the machining to spread to move , and also can t produce the mechanical trouble , therefore increased to recognize the dish the speed , and however and also lowered the cost . but adoption this project of generation is with part of the next generation dvd nonsupports cdr 4單聚焦單鏡頭:為panasonic率先采用的單激光頭單聚焦鏡雙聚焦點方案,他采用特別的全息綜合透鏡,通過透鏡中間部分的激光束形成cd的聚焦點,通過透鏡邊緣部分的激光束形成dvd的聚焦點,這種結構由于沒有機械傳動,也不會產生機械故障,所以提高了認盤速度,不過同時也降低了成本。但采用此方案的第一代和部分第二代dvd不支持cdr 。