OPTICAL SCANNER

摘要

1455106 Optical scanners RAPIFAX CORP 8 Jan 1974 [8 Jan 1973] 00887/74 Heading G2J An optical line scanning system comprises means for focusing an image of a straight line upon the arc of a circle, a field stop and means for causing it to traverse a circle such traversing means mounting the field stop for rotating the latter about an axis which orthogonally intersects the plane at a point offset from the optical centre of the focusing means which centre is disposed in the plane of the circle. As shown in Figs. 1, 2, 3 a line 110 to be scanned on paper 10 placed on transparent support 11 is illuminated by elongate lamp filament 15 at one focus of an elliptic reflector 12 whereby the light is reflected on to the line at the other focus. A sheet pencil of light passes through elongate slot 13 in the reflection to elongate plane mirror 16 from which it is reflected on to spherical mirror 20 forming the back wall of a box 19 having a semi-circular front opening 18 enclosing the centre of curvature 101 of mirror 20 which is offset from the center 100 of rotation of drum 17, for admitting the light. Mirror 20 then focuses the light on to the circular edge at the juncture 120 of the top wall 17a and side wall 17b of a cylindrical drum rotatable vertical shaft 25 by motor 29 and belt 28. Within drum 17 optical fibres 21, 22 spaced at equal radial intervals extend through the juncture 120 to transmit light pulses corresponding to parts of line 110 to sensor 23 and amplifier 24 as container 17 rotates. The axis of the mirror 20 coincides with the top of the drum in line with vertical image 111 of line 110. Secured to the bottom of the drum is a transparent code disc 31 carrying a clock track 31a, 31b illuminated by light 34 focused on detector 40 through mask 38, whereby the output of detector 40 indicates the displacement of the drum corresponding to the position of a point being scanned on line 110. In another embodiment Fig. 5 (not shown) light at 120 passes through a series of pin-holes in drum 17 where it is focused by a half-lens on to a detector within the drum. In the embodiment of Fig. 6 the image of line 110 is focused by half lens 18a on the inner circular edge 120 of a recessed drum 17 having optic fibres 21, 22 exposed at the edge. The lens 18a is offset from the axis of the drum.