White LED-based Integrating Sphere Offers Superior Luminance Calibration of Imaging Sensors

Alex Fong, G&H (Orlando)

The light measurement instrumentation and imaging detector industry relies heavily upon conventional single line spectrum and continuous sources. Typically incandescent, they provide only limited utility in terms of reliability, accuracy, control of spectral content and serviceable life. A new product under development by Gooch & Housego will allow an unprecedented level of flexibility in terms of uniformity and linearity testing for designers, integrators and end-users.

G&H’s white LED-based integrating sphere
G&H’s white LED-based integrating sphere

The source addresses the needs of engineers, scientists and technicians who currently work with conventional incandescent-based line and filtered broadband sources but desire a cost-effective, wavelength-selectable, NIST-traceable radiant light source. In such applications, the LED Integrating Sphere Source provides more versatility and better performance than filtered sources and is a significantly lower cost alternative to monochromators and similar instruments. Main application areas include product testing and detector, imaging system and photometric instrument calibration. Also unlike tungsten halogen lamps, LEDs will not heat parts significantly due to radiation, so the optical cavity can be small. It does not require air flow, so the cavity is easily rendered light tight. The heat can be conducted to a heat sink and dissipated using inexpensive, readily available assemblies. Calibrations will be available in luminance, radiance and illuminance/irradiance.

There are a few white LED-based luminance sources in the market place but until now they have only been able to generate a uniform spectral output across a limited range. The proprietary design of this new system from G&H is unique in overcoming that limitation, offering a true broadband output as good or better than conventional sources. For more information on the G&H White LED-based Integrating Sphere; specifications and applications, contact Alex Fong or orlandosales@goochandhousego.com.