Abstract: An apparatus for detecting a polarization altering substance, such as ice, on a surface includes a polarizing filter on the surface between the surface and the polarization altering substance. When the polarizing filter includes alternating regions having orthogonal polarizing properties, only one viewing of the surface through a blocking filter is required. When light, either polarized or unpolarized, reflects off the surface, it passes through the polarizing filter and becomes polarized. Reflected light that additionally passes through ice after leaving the polarizer becomes unpolarized. When viewed through a blocking polarizer filter, polarized light passing through ice appears bright due to the unpolarizing effect of ice. On the other hand, polarized light not passing through ice retains its polarization and appears dark when viewed through a blocking filter.

Abstract: An apparatus for detecting a polarization altering substance, such as ice, on a surface includes a polarizing filter on the surface between the surface and the polarization altering substance. When the polarizing filter includes alternating regions having orthogonal polarizing properties, only one viewing of the surface through a blocking filter is required. When light, either polarized or unpolarized, reflects off the surface, it passes through the polarizing filter and becomes polarized. Reflected light that additionally passes through ice after leaving the polarizer becomes unpolarized. When viewed through a blocking polarizer filter, polarized light passing through ice appears bright due to the unpolarizing effect of ice. On the other hand, polarized light not passing through ice retains its polarization and appears dark when viewed through a blocking filter.

Abstract: A position sensing detector in which each of a plurality of sensing channels is provided with ends and an output current lead at each end of each channel. A light spot is imaged along the length of the channel. The channels are electrically isolated from each other. The channels may be proportional to a selected keystone pattern, and the channels may be rectangular-shaped and accommodate keystoning effects of an imaged beam.

Abstract: A position sensing detector in which each of a plurality of sensing channels is provided with ends and an output current lead at each end of each channel. A light spot is imaged along the length of the channel. The channels are electrically isolated from each other. The channels may be proportional to a selected keystone pattern, and the channels may be rectangular-shaped and accommodate keystoning effects of an imaged beam.

Abstract: A method for producing relative motion on multiple articles by providing a tray with cavities, locating each article in a separate cavity and banking all articles against a similar cavity wall without tilting the tray, movement of the articles being generated by placing the tray between a horizontal vibration device and at least one cooperating bumper, the vibrations having an amplitude decreasing with time according to a predetermined decay envelope.