Abstract: A method and apparatus for inspecting glass tubes for fire checks and other defects is disclosed. Each tube is positioned on transport equipment and moved through an inspection area as it is rotated about its longitudinal axis by a spinner mechanism. A broad source of diffused light illuminates each tube in the inspection area. A camera is positioned above the moving line of tubes and includes an array of photosensitive diodes arranged parallel to the longitudinal axes of the tubes. A check in a tube will reflect a higher intensity light to the camera than a non-defective portion of the tube. By averaging the signals from the first few diodes for each longitudinal scan of the camera, a reference voltage level can be electronically determined for each scan. Any signal generated by a diode element of the camera which is greater than the sum of the reference signal and a predetermined signal indicates the presence of a defect in the tube.

Abstract: This invention relates to a method and apparatus for determining whether a glue drop is present on the reflective inner surface of a closure. Collimated light is projected onto the reflective inner surface of the closure, and a measurement is taken of the amount of light which remains collimated after reflection from the closure. The measurement of the amount of light reflected in this way is used to determine whether a glue drop is present.

Abstract: A method for measuring the thickness of transparent articles utilizing a plural component light beam. In the most general sense, the present invention involves the generation of a plural component light beam which is generally symmetric about the optic axis of the system. The light distribution which results from this arrangement is used to illuminate a transparent article. The result is separate reflections from the front and rear surfaces of the article for all of the components of the light beam. If these reflections are imaged in a detector plane which is conjugate to a plane in the vicinity of the article, a pair of co-planar images are formed, one image representing reflections of all of the plural components from the rear surface and the other image representing reflection of all of the plural components from the front surface. Measurement of the average separation of the images will give a value that is proportional to the thickness of the article at a point lying along the optic axis of the system.

Abstract: There is disclosed the magnetic polarization of a tubular gaseous laser device comprising a laser capillary tube with anode and laser end pieces, a cathode, a cathode envelope, and a gas exhaust stem for filling the device with a laseable gas. Magnetic polarization of the light output from the laser is achieved by applying a magnetic field to the lasing capillary and the rotation of the laser within the magnetic field to optimize the extinction ratio.

Abstract: There is disclosed a passive mirror alignment system to permit alignment of the output coupler of a gas laser device relative to the flat mirror so as to produce the necessary optical resonator without the need to evacuate, backfill with gas, and maintain a plasma within the device.