Overview
ISO 13915:2023 - Fine ceramics (advanced ceramics) - Test method for optical properties of ceramic phosphors for white light‑emitting diodes with reference materials - specifies a substitution measurement method to determine the internal quantum efficiency (IQE), external quantum efficiency (EQE) and absorptance of ceramic phosphor powders used in white LEDs. The method uses commercially available instruments (e.g., fluorescence spectrophotometers or spectroradiometers with a monochromatic excitation source) to measure fluorescence spectra of a test phosphor and of reference materials whose optical properties have been previously determined using ISO 23946.
Key topics and technical requirements
- Measurement scope: IQE, EQE and absorptance of ceramic phosphors that emit visible light under UV or blue excitation.
- Substitution approach: Uses reference materials characterized by ISO 23946 (gonio‑spectrofluorometer methods) to enable practical measurements with common lab equipment.
- Apparatus components: Light source unit (monochromator or laser), sample unit (cell, cell holder), detection unit (directing optics, spectrometer, detector, amplifier) and signal/data processing.
- Calibration and maintenance: Wavelength calibration of source and detector, spectral responsivity calibration, and cell inspection requirements.
- Sample handling: Reference material selection, storage, pre‑processing and procedures for filling cells with phosphor powders.
- Measurement procedures: Environment control, spectrometer setup for substitution measurement, measurements for reference and test materials.
- Calculations: Spectral responsivity correction, conversion to photon‑based spectral distributions, separation of scattered light and fluorescence photon counts, and computation of EQE, absorptance and IQE.
- Informative annexes: Wavelength correction methods, chromaticity coordinate correction, and guidance on related ISO documents.
Practical applications and users
- Who uses it: Phosphor manufacturers, white LED device makers, R&D labs, materials scientists, quality control and calibration laboratories, and standards/metrology bodies.
- Why it matters: Enables reliable, comparable evaluation of ceramic phosphor optical performance (IQE, EQE, absorptance) using readily available instruments - useful for product development, competitive benchmarking, quality assurance and certification.
- Use cases: Material selection for SSL (solid‑state lighting), validating reference phosphors, routine QC of ceramic phosphor batches, and optical characterization for LEDs beyond white (e.g., green, orange).
Related standards
- ISO 23946 - Gonio‑spectrofluorometer methods for absolute EQE, IQE and absorptance (reference material characterization).
- ISO 20351 - Integrating sphere method for absolute IQE measurement.
- ISO/CIE 11664‑3 and CIE S 017/E - Colorimetry and lighting vocabulary referenced for definitions and chromaticity corrections.
Keywords: ISO 13915:2023, ceramic phosphors, white LEDs, internal quantum efficiency, external quantum efficiency, absorptance, fluorescence spectrophotometer, spectroradiometer, ISO 23946, ISO 20351.
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