| 摘要 |
<p>Provided are an endoscope objective lens that has a simple configuration and is suitable for a compact, high-resolution image acquisition device usable in laser treatment and the like, and an endoscope using the same. Provided is an endoscope objective lens 1 including, in sequence from an object side, a front group (FG), an aperture stop (S), and a back group (BG). The front group (FG) includes, in sequence from the object side, a negative first lens (L1) whose concave surface faces an image side, a positive second lens (L2) whose convex surface faces the object side and whose flat surface or concave surface is located on the image side, and a filter (FL). The back group (BG) includes, in sequence from the object side, a positive third lens (L3) whose convex surface faces the image side, and a combined lens (E45) formed of a plano-convex lens or a biconvex lens (L4) and a negative meniscus lens (L5) and satisfies the following Conditional Expression (1) n �¢ 3 > - ½ �¢ 3 / 12 + 5.5 where n3 is the refractive index of the third lens (L3), and ½3 is the Abbe number of the third lens (L3).</p> |
