樹脂筐体を採用した薄型光学ヘッドの耐環境実装構造

摘要

Servo signals, such the focusing or tracking error signals of an optical head, are generated from the position or the intensity distribution of the beam spot on the detector. If the beam spot position on the detector deviates as ambient temperatures change, the servo signals fluctuate. Therefore, reducing the position deviation is necessary in order to obtain highly reliable reading or writing operations. We derived a formula where the position deviation of the beam spot on the detector with temperature is approximately expressed as a linear combination of the factors of the position deviations caused by displacement and tilt of each optical part. To reduce the position deviation of the beam spot, we developed a method where effect of one optical part on the position deviation offsets that of another optical part. Using this method, we developed a jisso structure of a slim optical head utilizing a resin housing. The measured position deviation on the detector is 6.2% of the diameter of the beam spot or less at ambient temperatures between 0 and 65℃.%光学ヘッドは，レーザから照射される出射光をディスクrnの記録面に対物レンズで集光させたスポットを用いて情報rnの記録再生を行う装置で，ディスクの面振れや偏芯といっrnた外乱に対して，対物レンズの焦点位置をディスクの記録rn面上にある所定のトラックに一致させるために,対物レンrnズの位置を対物レンズの光軸方向であるフォーカシング方rn向とディスクの半径方向であるトラッキング方向に制御しrnている．