抄録
The design of a mid-infrared high dispersion spectrograph with a resolution of 200000 at 10μm employing Germanium Immersion Grating (GIG) element is required for the 8.2m SUBURA large space telescope. The GIG element with a large number of sharp and smooth micro V-grooves need to be fabricated. Previous study focused on development of micro-grinding process with ELID and its prototype fabrication, developed grinding systems are not applicable to its fabrication because of small machining space and fast wear of small grinding wheel. Therefore, the aim of present research is to develop a new grinding system to fabricate larger GIG and to put the GIG elements to practical use. The authors applied a large ultra-precision mirror surface grinding system and an precision micro-grinding technique, carried out experimental study. This paper described the process principle, grinding equipment and basic grinding experimental results by utilizing metal bonded diamond grinding wheel #4000. The micro-grinding technique combines precision micro-truing and ultra-precision fine grinding. The minimum wheel tip radius of 8.2μm was achieved using the grinding wheel #4000 by the micro-truing process. The corner radius of 15μm∿25.8μm of V-grooves was achieved using grinding wheel #4000.
