STEMMER IMAGING

The term light propagation describes the manner in which light strikes an object. We will be concerned with the effects of collimation, structure, focus and diffusion. In the diagram below, these have been arranged together on a scale that has structured laser light at one extreme, and diffuse light at the other. In this context it should be noted that the terms diffuse and even when related to illumination, are not explicitly the same.

Examples:

• Structured
  Coherent laser light where the waves/photons share the same phase

• Collimated
  Collimated on-axis illumination, where the rays of the light are all parallel

• Focused
  Focused laser light, or a line light that is focused onto the surface of a web

• Direct
  LED light, where the light from the array has a direct path to the target

• Diffuse
  LED light, where the light from the array passes through a diffusing material

Related content:

• Uniformity of illumination
• Illumination
• Suitable illumination technologies and Important factors affecting lighting