| 摘要 |
In a linear tracking pickup apparatus of a record player, a video disc player and the like wherein a pickup arm is swingably and pivotally supported on a gimbal support mechanism, a device for detecting an offset angle of the pickup arm comprising: a light-reflecting surface formed on a portion of a first frame as a part of the surface of this portion, which first frame being a portion of the gimbal support mechanism and swingable with the horizontal swing of the pickup arm; a light-emitting source fixed to a second frame, not swingable but only linearly movable, of the gimbal support mechanism so as to face the light-reflecting surface; and a photo-sensitive element fixed to the second frame for receiving the light rays reflected by the light-reflecting surface. This arrangement is free of any such eccentric load otherwise placed additionally on the pickup arm via its support mechanism on which a detector is to be mounted in the conventional art, and a desirable lateral balance of the pickup arm is maintained throughout the reproduction.
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