Photometric Data For The Contour Projector

Photometric data shown for the Contour projector is derived from measurements of luminous intensity (candela) at various angles measured from the projector aiming direction. Measurements, in a common procedure, involve placing the projector in a light absorbing room or tunnel having a photometer placed opposite the projector. Separation of the projector and photometer must be sufficient to avoid short range effects related to optical source size, as well as be small enough to produce accurate readings of intensity on the particular photometer used. The projector is rotated in angular steps about two axes and intensity data is recorded as a function of horizontal and vertical angle. The data is then entered into a tabular format developed by the Illuminating Engineering Society (IES.) A text file containing IES data is readable by several types of software that can be used to display candela vs. angle data for the projector. The data shown is normalized, i.e. every value measured is divided by the peak test value obtained, to remove the intensity drop with increasing distance. And, since the projector light distribution is symmetrical about a central axis (like a flashlight) only one “slice” of data is needed to characterize the output. The data shows that the light output is highly uniform, and maintains peak intensity out to the sharp edge defining the open aperture field of view. For example, the very wide intensity profile of the Contour Projector shows uniform, full light intensity filling a cone about 80 degrees wide (2 X the 40 degrees shown because of symmetry.) Projecting this light on a facing wall will produce a very uniformly lighted circle. The sharp drop from full intensity to zero intensity shown in the photometric data indicates the ability of the Phantom Contout Projector to provide very crisp images of whatever pattern or gobo is being projected, as well as showing the absence of stray light in the beam.