| 摘要 |
<p>An objective lens includes, in order from the object side, a first lens (L1) with negative power, a second lens (L2, L2') with positive power, an aperture stop (AS), and a third lens (L3) with positive power. A lens component located on the image side of the aperture stop (AS) is constructed with a positive single lens or a plurality of positive single lenses, and the objective lens satisfies the following conditions:<MathDetails id="matha01"><MathText><![CDATA[ <math display="block"><mrow><mtext>45 < νd1 - νd2</mtext></mrow></math><img id="ia01" file="imga0001.tif" wi="29" he="3" img-content="math" img-format="tif" /> ]]></MathText></MathDetails><MathDetails id="matha02"><MathText><![CDATA[ <math display="block"><mrow><mtext>-0.6 < f1 / f2 < -0.3</mtext></mrow></math><img id="ia02" file="imga0002.tif" wi="38" he="3" img-content="math" img-format="tif" /> ]]></MathText></MathDetails> where νd1 is the Abbe's number of the first lens, νd2 is the Abbe's number of the second lens, f1 is the focal length of the first lens, and f2 is the focal length of the second lens.</p> |
