GB1151271A - Automatic + X-Axis Detector, Marker, Sorter and Collector for Crystal Wafer Blanks - Google Patents

Abstract

1,151,271. Shoots. AIKEN INDUSTRIES Inc. 15 Feb., 1967, No. 7301/67. Heading B8S. [Also in Division G1] The + X-axis of quartz crystal wafer blanks is detected photo-electrically using polarized light in order that the crystals may be collected together in the same orientation. In one arrangement, Figs. 3 and 4, in which the crystals are sorted and collected into four groups of different + X-axis orientation, the individual crystals are marked to indicate the +X-axis orientation. A crystal CW arrives at the window 70 of the detection station and is held there by a solenoid-operated finger 74 while the - X-axis orientation is detected. This is done by use of a system (shown diagrammatically in Fig. 4) including a light source 188 directing light on to four mirrors 190 so that four light beams are passed through the corners of the crystal CW from beneath the latter. Four pairs of photo-resistive cells 212a-212d are arranged to receive the respective light beams through polarizers. The pairs of cells are connected in a bridge network forming part of the control circuit 214 (detailed in Fig. 13, not shown). Unbalance of the bridge can occur in four ways to cause energization and/or non- energization of solenoids 92 and 106 through SCR's and a timing circuit including a relaxation oscillator for delay purposes, in four different combinations causing actuation and/or non-actuation of blade members 90, and 102 and 104. Thus a crystal CW can be directed into an appropriate branch 62, 64, 66 or 68 (formed as grooves in the sloping board 24). Amotor 136 continuously drives a shaft 133 which, through cams, Figs. 5-7 (not shown), causes stop fingers (156) to be raised periodically in grooves 62-68 to stop any crystal to allow a marker assembly 140 to mark the crystal with the appropriate + X-axis orientation indication, and also causes a crystal, on arrival at the bottom of a groove, to be fed into a magazine 52. When full, a magazine, Figs. 9-12 (not shown), is removed by unscrewing screws 130. An arrangement is also described, Fig. 16 (not shown), in which the grooves in the sloping board are specially shaped to cause rotation, through 90 or 180 degrees, of some of the crystals after release from the detection station, so as to arrange all the crystals in a single + X- axis orientation direction at a single collector station. An arrangement in which there is only a single guide path for blanks, from detection station to collector station, Fig. 17 (not shown), uses a turn-table controlled in accordance with the detector circuit output, to rotate crystals as required so as to all be similarly +X-axis orientated. Instead of using a plurality of light beams in the photo-electric system, a single polarized beam may be used, the crystal being rotated during detection.