公开(公告)号：EP0454854B1

公开(公告)日：1996-01-03

申请号：EP90914962.7

申请日：1990-10-15

申请人： COPAL COMPANY LIMITED ,  FUJITSU LIMITED

发明人： HOSOBATA, Nobuhiko ,  YOSHIKAWA, Yukio ,  TAKAGI, Masaaki

IPC分类号： G11B7/09

CPC分类号： G11B11/10576 ,  G11B7/0912 ,  G11B7/093 ,  G11B7/0932 ,  G11B7/094 ,  G11B7/0943 ,  G11B7/13 ,  G11B7/133 ,  G11B11/105

摘要： A device for adjusting the focal point of an optical pickup device in which the light reflected by a recording medium is focused at points of two systems using an optical branching filter, first and second light detectors are disposed, respectively, in front of one focal point and at the back of the other focal point, and a focal point adjusting mechanism is servo-controlled in response to the outputs from the two light detectors. Each of the light detectors has a central light-receiving surface on the optical axis and a peripheral light-receiving surface in the periphery of the central light-receiving surface. According to a first method, the focal point adjusting mechanism is servo-controlled such that the deviation will become zero between the ratio of the amount of light received in the center to the total amount of light received in the center and periphery of the first light detector and the ratio of the amount of light in the center to the total amount of light in the center and periphery of the second light detector. Even if the two detectors receive different amounts of light, the difference is cancelled between the denominator and the numerator of the ratio of the amount of light in the center to the total amount of light in the center and periphery, and the device is not affected by the imbalance in the amount of light. According to a second method, the focal point adjusting mechanism is basically servo-controlled based on the difference between the amounts of light received in the centers of the two light detectors. Here, the difference in the total amount of light received by the two light detectors is calculated throughout all stages, and the difference is used to calculate a correction value multiplied by the component ratio of the amount of light in the center to the total amount of the light received in a focused condition. Since the calculated correction value is subtracted from the difference in the amount of light received in the centers, the servo output does not contain imbalance in the amount of light falling on the light detectors of the two systems, and the device is not affected by the imbalance in the amount of incident light.

公开(公告)号：EP0454854A1

公开(公告)日：1991-11-06

申请号：EP90914962.7

申请日：1990-10-15

申请人： COPAL COMPANY LIMITED ,  FUJITSU LIMITED

发明人： HOSOBATA, Nobuhiko ,  YOSHIKAWA, Yukio ,  TAKAGI, Masaaki

IPC分类号： G11B7/09

CPC分类号： G11B11/10576 ,  G11B7/0912 ,  G11B7/093 ,  G11B7/0932 ,  G11B7/094 ,  G11B7/0943 ,  G11B7/13 ,  G11B7/133 ,  G11B11/105

摘要： A device for adjusting the focal point of an optical pickup device in which the light reflected by a recording medium is focused at points of two systems using an optical branching filter, first and second light detectors are disposed, respectively, in front of one focal point and at the back of the other focal point, and a focal point adjusting mechanism is servo-controlled in response to the outputs from the two light detectors. Each of the light detectors has a central light-receiving surface on the optical axis and a peripheral light-receiving surface in the periphery of the central light-receiving surface. According to a first method, the focal point adjusting mechanism is servo-controlled such that the deviation will become zero between the ratio of the amount of light received in the center to the total amount of light received in the center and periphery of the first light detector and the ratio of the amount of light in the center to the total amount of light in the center and periphery of the second light detector. Even if the two detectors receive different amounts of light, the difference is cancelled between the denominator and the numerator of the ratio of the amount of light in the center to the total amount of light in the center and periphery, and the device is not affected by the imbalance in the amount of light. According to a second method, the focal point adjusting mechanism is basically servo-controlled based on the difference between the amounts of light received in the centers of the two light detectors. Here, the difference in the total amount of light received by the two light detectors is calculated throughout all stages, and the difference is used to calculate a correction value multiplied by the component ratio of the amount of light in the center to the total amount of the light received in a focused condition. Since the calculated correction value is subtracted from the difference in the amount of light received in the centers, the servo output does not contain imbalance in the amount of light falling on the light detectors of the two systems, and the device is not affected by the imbalance in the amount of incident light.

摘要翻译： 焦点调整机构被伺服控制，使得在中心接收的光量与在第一光检测器的中心和周边接收的光的总量的比率之间的偏差将变为零，以及 中心的光量相对于第二检测器的中心和周边的总光量。 即使检测器接收到不同的光量，在中心和中心的总光量的比例的分母与分子之间的差异被抵消，并且该装置不受 光量不平衡。 或者，基于在两个检测器的中心中接收的光量之间的差异来对焦点调节机构进行伺服控制。 这里，在所有阶段都计算出由检测器接收的光的总安装量的差异，并且差异用于计算校正值乘以中心的光量与光的总安装量的分量比 在集中的情况下收到。 由于从中心接收的光量的差减去计算出的校正值，所以伺服输出不包含落在两个系统的检测器上的光量的不平衡，并且该装置不受不平衡的影响 在入射光量。 @（35pp Dwg.No.5 / 11）@。