Mr. Kenichi Hamamura Profile

Kenichi Hamamura

at KYOCERA Corp

SPIE Involvement:

Author

Publications (1)

This will count as one of your downloads.

You will have access to both the presentation and article (if available).

DOWNLOAD NOW

This content is available for download via your institution's subscription. To access this item, please sign in to your personal account.

Email or Username Forgot your username?

Password Forgot your password?

Show

Keep me signed in

No SPIE account? Create an account

Proceedings Article | 13 December 2020 Poster + Paper

F-molding: a new production method for largely aspherical mirrors of Cordierite

Hidehito Himeno, Yuji Ikeda, Shinji Mukai, Hidenori Yamanokuchi, Takato Honjo, Yuuki Nishi, Shinichi Yamaguchi, Kenichi Hamamura, Junpei Yamaguchi, Masatsugu Kamiura, Shinobu Nagata

Proceedings Volume 11451, 114512X (2020) https://doi.org/10.1117/12.2562006

KEYWORDS: Mirrors, Astronomy, Glasses, Raw materials, Polishing, Surface finishing, Surface roughness, Light scattering, Liquids, Segmented mirrors

Read Abstract +

Cordierite is a ceramic with low thermal expansion properties similar to Zerodure and ULE glasses in large-mirror telescopes used in Astronomy. Coefficient of thermal expansion of Cordierite is not only comparable to low thermal expansion glasses, but also has additional advantages with minimal dimensional deformation with time (~3.8nm/m/year), high Young's modulus (~145GPa), and high thermal conductivity (~4W/mK). However, Cordierite mirror is susceptible to voids generated by crushed grains leading to tetrahedral gaps from sphere packing of raw powder material during CIP (Cold Isostatic Pressing) process. These voids often appear with mirror polishing of Cordierite and may become a source of light scattering. To solve this problem, we propose Flexible Molding (Fmolding) as our new fabrication method for Cordierite. With F-molding, raw material powder is converted to liquid slurry which is then poured into a resin mold and solidified directly into near net shape of a mirror. Liquid slurry of Fmolding are thus cured in forming without pressurized sphere packing which generates void defects. In addition, the mold prepared from F-molding is an effective tool for processing multiple volumes of identical structures and is an ideal process for segmented mirror designs. To confirm the feasibility of F-molding for large mirrors used in Astronomy, we prepared a light-weighted flat mirror (270 mm in diameter) using the method with our Cordierite. In this paper, we introduce details of our F-molding mirror fabrication method, and report on measurement results of its optical performances.

My Library

You currently do not have any folders to save your paper to! Create a new folder below.

Folder Name

Folder Description

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks. You are receiving this notice because your organization may not have SPIE eBooks access.*

*Shibboleth/Open Athens users─please sign in to access your institution's subscriptions.

To obtain this item, you may purchase the complete book in print or electronic format on SPIE.org.

ORGANIZATIONAL
Sign in with credentials provided by your organization.

Organizational Username

Organizational Password

Show/Hide Password

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

;

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members:

Non-members: ADD TO CART

Keywords/Phrases

Search In:

Publication Years