設計・制御
Polariscope Acceptance Standard
Japanese: 偏光板検査基準
Recommended retardation pass criteria for fusing-notebook: ≤20 nm/cm (excellent), 20–50 (acceptable), 50–100 (caution), >100 (unacceptable/recommend re-annealing).
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The Polariscope Acceptance Standard is a criterion for determining acceptance or rejection based on the retardation value (nm/cm) measured by a polarizer to assess residual stress within the glass (Treatise §18.4). The standards recommended by fusing-notebook (a production tool created by Rei Chikaoka) are as follows: ≤20 nm/cm (Excellent: Equivalent to ASTM precision standards, long-term stability), 20–50 nm/cm (Acceptable: Suitable for use in artwork but residual stress remains), 50–100 nm/cm (Caution: Risk of cracking in thick or large pieces), >100 nm/cm (Unacceptable: Exceeds Bullseye threshold; re-annealing recommended).
This standard is set slightly less strictly than the acceptance criteria recommended by Bullseye Glass Co. (10 nm/cm or less; 5 nm/cm or less for storage quality) and represents a reasonable range for glass intended for practical use by artists (artworks and items for sale). The measurement method uses two linear polarizers and λ/ 4 waveplates (simplified version in accordance with ASTM F218). The retardation value [nm] is read from the interference colors by cross-referencing with the Michel-Lévy color chart, and the result is divided by the sample thickness [cm] to calculate the value in nm/cm. Actual measurements of OYF’s proprietary polarizing plate formulation (April 2026) yielded results indicating that even with shorter firing times than the theoretical values, the values fall within the acceptable range of ≤50 nm/cm; this serves as initial evidence of OYF’s rapid stress relaxation rate.
Related Concepts
偏光板テスト（polariscope-test）・残留応力（retardation）・光弾性（photoelasticity）・応力光学係数（stress-optical-coeff）・Adams-Williamson則（adams-williamson-rule）・OYFガラス（oyf-glass）
This entry is written in Japanese by Rei Chikaoka and translated for readers outside Japan. If something reads oddly, the original is the source of truth.