Photometry, Colorimetry & Spectroradiometry -
a Training Course on the Science of Light Measurement
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The training course defines the basic science and metrics used in the photometry, colorimetry, spectroradiometry and goniophotometry of light sources and in particular LEDs and Solid State Lighting. LEDs are being used in increasing numbers in lighting and display applications, ranging from solid state lighting luminaires, display backlights, large area video displays and signage. The human eye is very sensitive to brightness and colour differences and the problem with LEDs is they cannot be manufactured with consistent optical properties, even within the same batch. This makes measuring LED output an important activity, but their small size, narrow spectral emissions, directionality and temperature dependence mean that traditional photometric and colorimetric measurement methods are not always the most appropriate. The course will explain the metrics used to describe the output of LEDs and luminaires, present the concept of useful light, review current industry standards and provide an overview of the available test equipment.
An overview of the course content follows. Pro-Lite is happy to tailor the course to suit specific needs. The course can be delivered at a client's site or at Pro-Lite's facility where delegates will benefit from access to our state-of-the-art photometric dark room and hands-on time wiith our photometers, integrating sphere systems, spectroradiometers and near-field goniophotometer.
To discuss your training requirements, please use our enquiry form.
Course Overview
Basic Concepts - Light & the Human Visual System
Light and the electromagnetic spectrum
Photopic response
Mesopic & scotopic vision
Basic Concepts - the Optical Properties of Materials
Diffuse reflectance & transmittance
Lambert's cosine law
Specular reflectance & transmittance
BRDF and scatterometry
Photometry
Luminous flux
Illuminance
Luminous intensity
Luminance
The invserse squared & cosine rules
Photometric field - near-field versus far-field
Converting between units
Colorimetry
Colour vision and tristimulus theory
CIE colour spaces
Chromaticity
Colour temperature
Standard illuminants
Dominant wavelength
Colour differences
Spectroradiometry
Spectral power distributions
Computation of photometric & colorimetric quantities
Colour rendering
Goniophotometry
Coordinate systems
Near-field goniophotometry
Far-field goniophotometry
Standard photometric data
Choosing Light Measurement Equipment
Photometers
Colorimeters
Spectroradiometers
Goniophotometers
Spectrophotometers
Scatterometers
LEDs & Solid State Lighting - the Measurement Challenges
LED binning & the effect on intensity & colour
LED phosphors & the effect on colour
Standards - CIE 127
Standards - IESNA LM 79 & 80
Spectral considerations
Geometric considerations
Electrical considerations
Thermal considerations
Special considerations when choosing equipment for testing LEDs
