OBJECTIVE LENS
To provide an objective lens for increasing a numerical aperture (NA) on an optical disc side of a condensing optical system that finely narrows a light beam onto the optical disc.SOLUTION: An objective lens 100 is a single lens of a double-sided convex lens having the NA and a refractive index n. A...
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| Sprache: | eng ; jpn |
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| Zusammenfassung: | To provide an objective lens for increasing a numerical aperture (NA) on an optical disc side of a condensing optical system that finely narrows a light beam onto the optical disc.SOLUTION: An objective lens 100 is a single lens of a double-sided convex lens having the NA and a refractive index n. A focal length f is 1 mm to 1.3 mm, a working distance Wd is 0.2 mm to 0.3, and the sag amount on each surface is always changed in the same direction from an optical axis toward the outer edge of the lens, and the numerical aperture NA is 0.94≥NA≥0.91.SELECTED DRAWING: Figure 1
【課題】光ディスク上へ光ビームを微小に絞る集光光学系の光ディスク側開口数（ＮＡ）を大きくする対物レンズを提供する。【解決手段】対物レンズ１００は、ＮＡ及び屈折率ｎを有する両面凸レンズの単レンズであって、焦点距離ｆが１ｍｍ〜１．３ｍｍで、作動距離Ｗｄが０．２ｍｍ〜０．３ｍｍであり、いずれの面のサグも、それぞれ光軸からレンズ外縁部に向かってサグ量が常に同じ方向に変化し、開口数ＮＡは０．９４≧ＮＡ≧０．９１である。【選択図】図１ |
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