IEC 60758:2016

Overview

IEC 60758:2016 - Synthetic quartz crystal - Specifications and guidelines for use - defines requirements, test methods and usage guidance for synthetic quartz single crystals used to manufacture piezoelectric elements (frequency control and selection) and optical components. This fifth edition reorganizes terms and definitions, removes the infrared absorbance coefficient α3410 as a standalone metric, adds FT‑IR measurement guidance, and extends coverage to synthetic quartz for optical applications.

Key technical topics and requirements

• Scope and definitions: Orientation, handedness and crystal axis/face designation for as‑grown and lumbered quartz.
• Dimensional and geometric requirements: Standard shapes, seed orientation, tolerances, reference surface flatness and angular tolerances for lumbered bars.
• Material quality and grading:
  • Inclusion density and striae grading for piezoelectric and optical uses.
  • Infrared quality indications and α‑value grading (measurements noted near ~3500 cm‑1 and ~3585 cm‑1).
  • Etch channel density classification and internal transmittance for optical parts.
• Measurement and test methods:
  • Visual inspection, schlieren (optical) evaluation, infrared absorbance methods.
  • Annex E: FT‑IR sample preparation, equipment set‑up and compensation procedures.
  • Annex G: consistency between dispersive IR and Fourier‑Transform IR (FT‑IR) measurements.
• Performance parameters: Frequency–temperature characteristics for piezoelectric elements and guidance on evaluating Q and α relationships.
• Quality assurance and delivery: Marking, packing, inspection lot rules, sampling procedures and batch/lot acceptance criteria.
• Informative annexes: Sampling examples, numerical examples, measurement tools (point calipers) and differences in axis conventions (IEC vs IEEE).

Practical applications and users

IEC 60758:2016 is essential for:

• Quartz crystal manufacturers: to specify production tolerances, grading and testing protocols for both piezoelectric and optical crystals.
• Component designers and OEMs: for sourcing materials for oscillators, filters, resonators, optical windows, lenses and photonics components requiring stringent optical/transmission properties.
• Quality, metrology and test laboratories: to implement consistent IR/FT‑IR measurement procedures, schlieren inspection and sampling plans.
• Procurement and compliance teams: to write purchase specifications, acceptance criteria and supplier audits.

Related standards and notes

• Annex F discusses differences between IEC and IEEE orthogonal axial systems - useful when aligning specifications across industry standards.
• For accurate IR measurement and traceability, follow guidance in Annex E (FT‑IR) and Annex G (measurement consistency).

Keywords: IEC 60758:2016, synthetic quartz crystal, piezoelectric, optical applications, FT‑IR, infrared absorbance, schlieren, etch channel density, frequency‑temperature.