Electronic structure analyses of the interface between a high refractive index optical glass and carbides

Yasuhiro Fujiwara, Takanori Kiguchi, Tomohiko Yoshioka, Kazuo Shinozaki, Junzo Tanaka

Research output: Contribution to journalArticle

Abstract

High refractive index aspheric glass lenses are often used in digital still cameras. However, in manufacturing, adhesion of softened glass to carbide mold causes various defects on the lens surface. We performed experimental transmission electron microscopy (TEM) observations and molecular dynamics/orbital calculations to investigate the glass-carbide adhesion mechanism. TEM revealed island-shaped glass adhesion on the surface of carbide (glassy carbon: GC). TEM-energy dispersion spectra (EDS) showed reduced atomic ratio of oxygen in adhered glass compared with bulk, indicating adhered glass could undergo reduction. From DV-Xα calculations focused on the oxygen atom on the surface of the glass; OI, as Nb-OI bonds at the glass surface approach GC, an overlap population between OI and C increases while that of the Nb-OI bonds decreases. This suggests that, in agreement with TEM-EDS results, OI of the Nb-OI bond forms no bridging bond such as Nb-OI-C at the glass-GC interface, while the C-OI bonding unit could be isolated at the GC surface, and supports our assumption that reduction of the glass induces adhesion to the GC mold.

Original languageEnglish
Pages (from-to)20-26
Number of pages7
JournalMaterials Science and Engineering B: Solid-State Materials for Advanced Technology
Volume161
Issue number1-3
DOIs
Publication statusPublished - 2009 Apr 15

Keywords

  • Adhesion
  • Digital camera
  • Direct-space method
  • Interfacial electronic states
  • Niobium phosphate glass
  • Transmission electron microscopy

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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