Complex objective lens including saw-tooth diffractive element for using on blue, red and infrared lights,申请号US201213558465-传众专利搜索

Complex objective lens including saw-tooth diffractive element for using on blue, red and infrared lights

申请公布号：US8441907(B2)

申请号：US201213558465

申请日期：2012.07.26

申请公布日期：2013.05.14

申请人：

KOMMA YOSHIAKI;TANAKA TOSHIYASU;YAMASAKI FUMITOMO;PANASONIC CORPORATION

发明人：KOMMA YOSHIAKI;TANAKA TOSHIYASU;YAMASAKI FUMITOMO

分类号：G11B7/00;G11B7/135

主分类号：G11B7/00

摘要：In an optical head device which performs recording/reading of data in/from a high-density optical disc using an objective lens with a large NA, a saw-tooth shape diffraction element is used for also performing recording/reading of data in/from a conventional optical disc, such as DVD, CD, or the like. A step difference that produces an optical path length for blue light which is equal to or longer than the wavelength of the blue light and optical path lengths for red and infrared light which are shorter than the wavelengths of the red and infrared light is utilized so as to exert an inverse action on the blue light to those exerted on the red and infrared light. The effect of increasing the working distances for CD and DVD enables multiple compatibility. The optical element is integrally combined with the objective lens to perform a tracking servo following operation.