Measurement Principle
The PhotonMetra P100 is a portable fiber-optic spectroscopic reflectometer designed for quantitative reflectance measurements on coated glass and transparent substrates. The optical measurement geometry selectively detects the reflection from the first surface while strongly suppressing contributions from the rear surface and multiple internal reflections.
The fiber-optic configuration provides stable illumination and signal collection, supporting reproducible measurements in both laboratory and industrial environments.
Spectral Range
250–1100 nm (UV–VIS–NIR).
Measurement Modes
The PhotonMetra P100 supports two measurement modes: First-Surface Reflectance and Total Reflectance. The appropriate mode is selected according to substrate thickness and the required optical information.
First-Surface Reflectance
First-Surface Reflectance measurement isolates the reflection from the coated front surface while strongly suppressing the contribution from the rear surface.
Measurements can be performed at 15° and 30°. Substrate thickness is an important parameter because it determines the spatial separation between the front- and rear-surface reflections.
For glass thicknesses of approximately 3 mm and above, the standard 15° measurement geometry is recommended. For thinner glass, the 30° geometry provides greater separation between the two reflections and can typically extend first-surface measurement capability down to approximately 1.5 mm.
Total Reflectance
For very thin transparent substrates, the front- and rear-surface reflections may no longer be reliably separated. In these cases, the PhotonMetra P100 can operate in Total Reflectance mode, measuring the combined reflectance of the complete transparent substrate.
This mode is suitable for thin glass and transparent polymer substrates and is useful when the total optical response of the complete component is more relevant than the reflectance of an individual surface.
Substrate Types
Suitable for coated glass, transparent plastics and other transparent substrates. Applications include flat glass, display and cover glass, solar glass and functional coated substrates.
Textured & Structured Solar Glass
Textured solar glass can strongly scatter reflected light, making conventional point measurements less representative of the macroscopic optical behaviour.
For structured solar glass, the P100 supports manual rotational probe scanning during measurement. This increases the effective sampling area and spatially averages local reflectance variations caused by the surface texture.
This scanning approach is specifically intended for structured surfaces and provides a more representative reflectance measurement of the coated solar glass.
Adjustable Integration Time
The measurement integration time can be adjusted according to the application.
This allows optimization of signal-to-noise ratio, measurement throughput and, for structured solar glass, the degree of spatial averaging during rotational scanning.
Portable & Stand-Alone Operation
The PhotonMetra P100 is designed as a portable stand-alone measurement system with an integrated computer and display.
Measurements, data review and basic analysis can be performed directly at the measurement location without requiring a separate external PC. Touchscreen operation is supported, while a keyboard and mouse can also be connected when preferred.
The system is suitable for laboratory, pilot-line and industrial production environments.
Optical Modelling
Optical modelling is strongly recommended when the PhotonMetra P100 is used for quantitative coating analysis.
Measured reflectance spectra can be combined with thin-film modelling and fitting software to determine coating parameters such as layer thickness, refractive index, multilayer structure and reflection color. This provides significantly more information than reflectance measurement alone and is particularly valuable for coating development, process optimization and troubleshooting.
For routine production control and rapid coating comparison, the measured reflectance spectra can also be used directly without optical modelling.
Typical Use
The PhotonMetra P100 supports applications ranging from coating development and laboratory analysis to solar-glass production control, display and cover glass inspection, thin-film validation and production quality assurance.