Olympus Medical Systems Corporation

Nederlandse Organisatie Voor Toegepast-natuurwetenschappelijk Onderzoek Tno

Yuko Katahira

Hiroaki Kinoshita

Atsushi Goto

Makoto Tanabe

Anne Jans Faber

Mathi Rongen

A glass for a light guide fiber GA1 is used in a core of a fiberof a light guide, and has a refractive index nd between 1.56 and 1.74. The glass for a light guide fiber GA1 has the following composition: (A) SiO: 20 to 55 wt %, (B11) BO: 0 to 2.0 wt %, (B2) does not contain POand GeO, (C1) (BaO+SrO+LaO+LuO+TaO+GdO+WO): 39 to 46 wt %, (D1) ZnO: 4 to 16 wt %, (E) does not contain AlO, (F) does not contain ZrO, (G) does not contain PbO and AsO, (H1) (NaO+KO): 4 to 10 wt %, (I) SbO: 0 to 0.050 wt %, and (J1) (NaSO+KSO): 0.32 to 0.78 wt %.

Glass for light guide fiber

An endoscope objective lens includes, in sequence from an object side, a front group which includes a negative first lens having a concave surface faces at image side, a filter, and a positive second lens having a convex surface at the object side and a flat surface or concave surface at the image side; an aperture stop; and a back group which includes a positive third lens having a convex surface at the image side, and a combined lens formed of a plano-convex lens or a biconvex lens and a negative meniscus lens, and satisfies the Conditional Expression (1) and (2):3&#x3e;&#x2212;&#x3bd;3/12+5.5,&#x2003;&#x2003;(1)2.0&#x3e;&#x3e;1.5.&#x2003;&#x2003;(2)

Endoscope objective lens and endoscope using the same

Provided is a simple-structured endoscope objective lens suitable for a compact, high-resolution image acquisition element. Provided is an objective lens constituted of a first negative lens, a second positive lens, an aperture stop, a third positive lens, and a joined lens arranged in that order from an object side, the joined lens being formed of a fourth positive lens and a fifth negative lens and satisfying the expressions (1) and (2), and the objective lens satisfies the expression (3):nn&#x2267;2.0&#x2003;&#x2003;(1)12&#x3c;(&#x3bd;)&#x3c;34&#x2003;&#x2003;(2)1.52&#x3c;(23/fl)&#x3c;1.75&#x2003;&#x2003;(3)where nn, &#x3bd;p, &#x3bd;n, fand fl denote a refractive index at d-line of the fifth lens, an Abbe number of the fourth lens, an Abbe number of the fifth lens, a combined focal length of the second lens and the third lens, and a focal length of the entire, respectively.

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Kawaguchi, Japan

Yuko Katahira