| 摘要 |
1,000,458. Photo-electric detection of flaws in transparent sheets. COMPAGNIE DE SAINTGOBAIN. Dec. 13, 1961 [Dec. 13,1960], No. 44668/61. Heading G1A. In a process for the continuous estimation of the polish quality or the body quality of a transparent sheet, wherein a beam of light is directed on to and through the sheet and is reflected back on itself through the sheet by reflecting means on the far side of the sheet, means are provided in the path of the reflected light on the near side of the sheet, to determine a characteristic of the light responsive to the presence of flaws on the transparent sheet. In the embodiment shown in Fig. 1, the image of the slit light source 1 is focused on a small rectangular mirror 4, the same size as the image, inclined to direct the light beam on to a mirror 6 revolving about an axis 10 at the centre of curvature of cylindrical mirror 8, to scan a sheet of glass 7. The light beam is focused on the mirror 10 by lens 5 and is reflected back along its path to pass back through the sheet to be refocused in the absence of flaws on the mirror 4. Scattered light however, caused by flaws in the glass sheet, is not focused by lens 5 on the mirror 4 but passes the mirror and energizes the photosensitive device 9. The optical system 1, 2, 4, 5, 6 and 9 may be turned perpendicular to the paper and oscillate about the axis 10 now coinciding with the optical axis from mirror 4 to mirror 6. In the second embodiment shown, Fig. 2, the mirrors 11 and 12, or the entire system, rotate horizontally about an axis 15 above a plane mirror 15, to scan the glass-sheet in a series of circular scans. Alternatively the mirror 4 may be replaced by a phase plate or a system of doubly-refracting prisms. For the average determination of the quality of a travelling sheet the scanning may be omitted and a light of constant direction used. |
