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BPC300 Photochromic Lens Spectrophotometer

The BPC300 spectrophotometer offers accurate characterisation of photochromic (photosensitive) lens transmission in the faded and AM2 conditioned states.


The fully automated BPC300 enables product testing of prescription and non-prescription sunglasses in accordance with international standards, and the development of photochromic formulations.

The versatile BPC300 permits darkening and fading-back kinetic studies, whilst the modification of sample temperature, conditioning beam illuminance and spectrum accounts for a broad range of lens exposure conditions. An optional polarising lens capability is on offer for the extension of the measurement scope.

Core benefits


  • Monochromator based, collimated tuneable light source (280-780nm)
  • Temperature-controlled water bath with mount for plano lens sample
  • AM2 conditioning beam (including facility to attenuate and filter spectrum)
  • Optically chopped monochromatic beam with lock-in signal recovery enables measurement under AM2 activation
  • Automated reference level measurement
  • Fully-automated by Windows application including establishment and running of pre-defined measurement profiles
  • Generation of measurement report including parameters required by standards


  • ISO/ EN 8980-3:2013 - “Ophthalmic optics. Uncut finished spectacle lenses. Transmittance specifications and test methods.”
  • ISO/ EN 12312-1:2013 - “Eye and face protection. Sunglasses and related eyewear. Sunglasses for general use.”
  • ANSI Z80.3: 2015 - “Non-prescription Sunglass and Fashion Eyewear Requirements.”
  • A S/NZS 1067-2016 - “Sunglasses and fashion spectacles.”

Reported Parameters

  • 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
  • Lens category
  • Colourimetric parameters: CIE 1931 & CIE Lab
  • 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
  • The rate of darkening and fading at a single wavelength

Optional reports include:

  • τVW : Luminous transmittance at (5±2)°C
  • τVS : Luminous transmittance at high temperature (35±2)°C
  • τVA : Luminous transmittance at reduced solar simulator level and (25±2)°C


Spectral range of operation280-780nm
Wavelength accuracy± 0.1nm (2400g/mm), ± 0.2nm (1200g/mm)
Beam diameter at sample plane4mm diameter
Measured transmission range0.5-100%
Maximum sample diameter75mm
Conditioning beamAM2 with requirements of ISO8980-3:2013
Optional filtering
Temperature range5-50°C
Temperature accuracy± 0.2°C
Bench space required1m deep x 2.5m wide
Services requirements6 x main sockets 1200W power consumption
Nitrogen gas supply where measurements below ambient are required

Monochromatic Probe Source

UV source30W Deuterium lamp
UV-Vis source100W Quartz Halogen lamp
Monochromator configurationSymmetric, single Czerny-Turner
Monochromator focal length300mm
Diffraction gratings2400 & 1200 g/mm
Diffraction grating mountTriple grating turret
Dispersion5.4nm/mm (2400g/mm)
Wavelength accuracy± 0.1nm (2400g/mm)
± 0.2nm (1200g/mm)
Chopping frequency175 Hz (typical)
Beam diameter at sample plan4mm diameter


bpc300 measurement data darkened and faded state

bpc300 measurement data darkening process

bpc300 measurement data fading process

Water Bath

Temperature range5-50°C
Temperature accuracy±1°C

Conditioning Beam

Spectral matchAM2 with requirements of ISO8980-3:2013
Beam illuminance0-50klx
Beam filteringOptional filtering

Computer requirements

OSWindows 7, Windows 8 (32-/64-bit) operating systems (or newer)
Software controlBenWin+ Spectral acquisition software
Minimum hard disk spaceApprox. 100MB
Minimum RAM2 GB
Interface4 x USB 2.0 ports


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