Functional checking of an optical channel

Claim 3

In the method of claim 1, wherein the optical channel includes beam-positioning means and an indication of a malfunction has been provided, the further steps of operating all elements of said channel except said beam positioning means in said predetermined state of operation and said beam-positioning means in a second predetermined state of operation after the malfunction indication is provided, and monitoring the intensity level of said directed beam to provide a second malfunction indication when the level of said intensity deviates from said predetermined level, whereby the presence of a malfunction is isolated to said beam-positioning means.

Claim 4

In an optical beam-projecting system having an optical channel including linearly polarized light beam generating means of predetermined intensity, an output medium and means acting on the polarization state of the beam for positioning it at any one of a plurality of discrete locations on said medium, the improvement comprising means positioned in the path of said beam between the positioning means and the output medium for deflecting all of said beam out of said channel and inhibiting the positioning of said beam on said medium when the generating means and positioning means are in a predetermined state of activation, said beam-deflecting means having in the order of the beam provided by the positioning means, means for orienting the lineaR polarization state of said beam into one of two mutually orthogonal linear polarization states, and birefringent means for providing said beam to the output medium when the beam has one of the polarization states and for providing the deflected beam from said channel when the beam from the orienting means has the orthogonal polarization state, and means outside of said channel responsive to the deflected beam for monitoring the intensity of said beam to provide an indication of any malfunction in said beam generating means and positioning means of said channel when the level of said intensity deviates from a predetermined level.

Claim 5

In an optical beam-projecting system having an optical channel including linearly polarized light beam generating means of predetermined intensity, an output medium and means acting on the polarization state of the beam for positioning it at any one of a plurality of discrete locations on said medium, the improvement comprising means positioned in the path of said beam between the positioning means and the output medium for deflecting all of said beam out of said channel and inhibiting the positioning of said beam on said medium when the generating means and positioning means are in a predetermined state of activation, said beam-deflecting means having in the order of the beam provided by the positioning means, means for orienting the lineaR polarization state of said beam into one of two mutually orthogonal linear polarization states, and birefringent means for providing said beam to the output medium when the beam has one of the polarization states and for providing the deflected beam from said channel when the beam from the orienting means has the orthogonal polarization state, and means outside of said channel responsive to the deflected beam for monitoring the intensity of said beam to provide an indication of any malfunction in said beam generating means and positioning means of said channel when the level of said intensity deviates from a predetermined level.

Claim 6

In the optical beam-projecting system of claim 3, wherein the system further comprises second monitoring means outside of said channel sequentially operative after the first monitoring means indicates a malfunction and when said beam positioning means is operated according to a second predetermined state of activation for monitoring the intensity of said deflected beam to provide an indication of a malfunction in said beam-positioning means.