Photochromic Lens Testing
The Bentham BPC300 is a turn-key solution for the characterisation of photochromic lens transmission in accordance with international standards and a key tool in the development of photochromic formulations.
The fully automated system yields transmission data for uncut finished lenses, in accordance with the EU Medical Devices Directive 93/42/EEC (implementing EN ISO 8980-3:2013) and for sunglasses in accordance with the EU Personal Protective Equipment directive, 89/686/EEC (implementing EN ISO 12312-1:2013).
Key features include:
• Measurement of spectral transmission 280-780nm in faded and darkened states
• Optically chopped monochromatic probe
• AM2 conditioning beam (including facility to attenuate and filter spectrum)
• Temperature-controlled water bath
• Fully-automated by the BenWin+ proprietary Windows application
• Generation of measurement report including parameters required by standards
Specification
| τV0 | Luminous transmittance in the faded state at (25±2)°C |
|---|---|
| τV1 | Luminous transmittance in the darkened state at (25±2)°C |
| τV0 /τV1 | Photochromic Response |
| τVW | Luminous transmittance at (5±2)°C |
| τVS | Luminous transmittance at high temperature (5±2)°C |
| τVA | Luminous transmittance at reduced solar simulator level and (25±2)°C |
| τSUVA | Mean UVA spectral transmittance weighted by AM2 |
| τSUVB | Mean UVB spectral transmittance weighted by AM2 |
| Qsign | Visual attenuation coefficient for red, green, blue and yellow incandescent |
| τsb | Solar blue light transmittance |
| Also reported are: | Lens category Colourimetric parameters: CIE 1931 & CIELab The rate of darkening and fading may also monitored at a single wavelength |
Table 2: Parameters reported by BPC300
