Length Standards Group

Length Standards are foundation of industries and sciences. We at Length Standards Section devote ourselves to various tasks in order to establish metrological standards and calibration system in the area of length (gauge blocks, line scales, EDM, laser interferometer, , step height, and refractive index) and deviation (flatness and sphericity) metrology. We construct efficient hierarchical traceability system in cooperation with calibration laboratories. At the same time, we conduct research and development activities regarding advanced length measurement science and technology.

What's New

Released on Dec. 3, 2024

Workshop of 2024FY annual research results of NMIJ (in Japanese) will be held from Jan. 16(Thu) to Jan. 17 (Fri), 2025 (given in Japanese). There will be one oral presentation and five poster presentations from our group. Participation registration is required. Your cooperation with advance registration by Janyary 10(Fri), 2025 is appreciated.

Released on Dec. 3, 2024

On Feb. 5, 2020, Dr. Kawashima, Dr. Hirai, Dr. Kondo and Dr. Bitou made an AIST press relase.
High-precision calibration of the surface profile of reference spherical lenses - Contributing to the development of high-precision optical elements and advanced product quality control -(in Japanese)
It was reported in OPTRONICS ONLINE on Nov. 29, 2024 (in Japanese).

Released on Oct. 25, 2024

A paper on alignment error analysis on spherical Fizeau interferometer and uncertainty evaluation of sphericity calibration system, authored by Dr. Kawashima, has been published online. Anyone can read or download the paper for free until December 13, 2024 from the link below, without signing in or registering.

Natsumi Kawashima, Yohan Kondo, Akiko Hirai, and Youichi Bitou, "Novel analysis of alignment error on spherical Fizeau interferometer and uncertainty evaluation of sphericity calibration system based on random ball test," Optics and Lasers in Engineering, 184, 108646 (2025).(New window will open.)

Released on Oct. 23, 2024

A review article on free-form surface shape measurement technology, authored by Dr. Kawashima was published in "Journal of the Society of Instrument and Control Engineers."

Natsumi Kawashima, "Review on free-form surface shape measurement technology and the establishment of standards," Journal of the Society of Instrument and Control Engineers, 63, 499 (2024). (in Japanese, New window will open.)

Released on Oct. 3, 2024

The "meter" was featured in the "Hajimari Kou" (Thoughts on the Beginning) column of the Yomiuri Shimbun evening edition on Wednesday, October 2, 2024. Dr. Hirai cooperated with the interview.

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Update List

Dec. 03, 2024: Update Members page.
(Dr. Kondo's concurrent position has been deleted and his information has been updated. Update the information of Dr. Kawashima and Dr. Masuda)
Mar. 18, 2024: Inquiry page of Inquiry · Access Guide is updated.
(The phone number and fax number of our research group have been deleted because these will be discontinued.)
Mar. 18, 2024: Update Dr. Hirai's page.
Oct. 05, 2023: Japanese page of Inquiry · Access Guide is updated.
(The address in Japanese has slightly changed due to reorganization. The address in English has not changed.)
Apr. 03, 2023: Update Members page.
(Dr. Kondo has returned from his secondment. Dr. Masuda has joined.)
Dec. 02, 2022: Update Dr. Hirai's page.
: Show all update list.

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