Design criteria for integrating sphere sources (ISS)
Design criteria for the configuration of integrating sphere light sources (ISS)
In this application, the integrating sphere provides a luminous field with highly uniform light distribution emitted from the output port. Therefore, integrating sphere light sources have become synonymous with the term "Uniform Light Sources". An important design criterion of the configuration is the arrangement of the light sources illuminating the sphere.
Variable and non-variable settings
Operating light sources such as halogen lamps within an integrating sphere enables almost all of their light output to be captured, but there is no way the luminance can be varied without affecting color temperature as a result of changing the operating current. However, it is possible to arrange multiple lamps in the sphere. In this way, the luminance at the sphere output can be varied in stages by turning the lamps on or off.
An adjustable aperture positioned between an external light source and the integrating sphere provides variable adjustment of luminance at the sphere output interchangeable fixed apertures are ideally suited. These can also be combined with continuously variable apertures. The efficiency of the light coupling into the sphere can be increased by using a reflector.
Semiconductor sources such as LEDs offer the possibility of changing the sphere’s radiance by regulating the operating current of the device.
lamp inside of integrating sphere -- external lamp with variable aperture -- LED lamp