Nikon Corporation

Masaaki Mochida

Hiroyuki Hiraiwa

Kazumasa Endo

Shigeru Sakuma

Kazuhiro Nakagawa

Norio Kaneko

Hiroshi Niikura

Minako Azumi

Atsushi Yanagisawa

Nobuhiro Tanaka

Yutaka Yamaguchi

A method for evaluating the refractive index homogeneity of an optical member includes passing light through an optical member () used for photolithography. The side surface () with respect to the optical axis (AX) of the optical member () is retained by elastic members () at a plurality of positions disposed at equal intervals to pass light through the optical member () and measure a wave front aberration. The optical member is rotated around the optical axis (AX) by the equal interval to measure a wave front aberration again and determine the difference from the initial measurement. The optical member () is moved in a direction perpendicular to the optical axis (AX) to measure a wave front aberration again and determined the difference from the initial measurement. The refractive index homogeneity of the optical member can be accurately evaluated from those differences by using fitting of the Zernike cylindrical function.

Method for evaluating refractive index homogeneity of optical member

An optical member manufacturing method of the present invention has a growth step of growing an ingot of a fluoride crystal, a plane orientation measurement step of measuring two or more crystal plane orientations of the ingot, a cutout step of cutting out an optical material from the ingot along any one of the crystal plane orientations obtained in the plane orientation measurement step, and a machining step of performing predetermined machining processing on the optical material to obtain an optical member.

Method for producing optical member

Optical member for photolithography and method of evaluating the same

A cylinder-type endosseous implant having a collar portion and a main type body portion formed under the collar portion. The implant also has screw threads, wherein the height of said screw threads is 0.2 to 0.4 mm; the pitch of said screw threads is 0.8 to 1.7 mm and the rising angle of said screw threads is determined to be at least 50.degree. and less than 90.degree.. The rising angle is defined to be the angle made by a root surface of the main body portion and the straight line which could be drawn from the top of a screw thread to the bottom of the same screw thread.

Endosseous implant

Growing community of inventors

Yamato, Japan

Masaaki Mochida