Abstract: The flanks of faults present in a surface produce abnormal reflection of a laser beam during linewise scanning of the surface by a laser beam. This apparatus deflects the angles of reflection from the surface, to indicate the presence of a flank, by a light conducting rod arranged parallel to the direction of linewise scanning for receiving reflected light on its surface and for conducting this light to its end face. The various light rays spread out transversely to the direction of scanning during their passage through the light conducting rod and are detected as they pass through a series of concentric annular apertures spaced from the end face of the light conducting rod. Each aperture is associated with a particular range of angles of incidence irrespective of the point on incidence along the surface of the rod and photoelectric detectors are used to sense the light passing through each aperture to provide the necessary indication of the presence or non-presence of a fault.

Abstract: A light conducting rod in which light incident on the surface of the rod is conducted along the rod to its end faces for subsequent detection. The light entering the rod is incident on three neighboring linear arrays of individual mirrors formed along the diametrically opposite surface of the rod; each individual mirror is inclined towards the axis of the rod and cylindrically curved so that the light is reflected back onto the internal surface of the rod at an angle which ensures total internal reflection.

Abstract: A light smoothing device for rendering a non uniform distribution of light more uniform especially suited for use in line scanning in combination with a light conducting rod which transmits light incident on its surface to its end faces for subsequent detection. The smoothing device has an optical passage with a reflecting interior surface an inlet to the passage and a detector at the other end of the passage. The passage ensures at least part of the light entering the inlet is reflected prior to incidence on the detector.A number of forms of optical passage are disclosed having various reflecting segments of convex, plain or concave curvature.

Abstract: A photo electric light detection device comprising an array of photodiodes is disposed at an end face of a light conducting rod in order to produce an output signal proportional to light incident on the surface of the rod and transmitted to the end face by total internal reflection. The array of photodiodes is subdivided into high and low pass frequency sub-arrays and the output signals from the sub-arrays are summed and processed to compensate for stray light. The device is useful in connection with a line scanner for detecting anomalies in a moving band.

Abstract: An electrooptical scanning device which can detect the relative position of register mark applied to a moving web, either serially on a single track or in two parallel, side-by-side tracks which extend in the direction of movement of the web. Light from a light source positioned some distance above the web is split into three light beams and the light beams are reflected downwardly towards the web. Lenses are positioned to receive and direct the light beam at an oblique angle onto the marks on the track or tracks. The lenses are aligned with the tracks and the light beam passing through a given lens is directed to the opposite track to illuminate three positions, two on the first track and one position on the second track. Light impinging on the web at these positions is scattered.

Abstract: Optical apparatus for extending a light curtain, using a light beam shifted periodically laterally parallel to itself onto an array of plane mirrors at an angle to the beam, the span of the array normal to the emergent reflected beam being greater than its span normal to the incident beam.

Abstract: A line scanning device for detecting defects in webs of material, wherein a laser light source throws a light spot by way of an objective, a light deflector device, and a cylindrical lens onto a web of material moving parallel to its surface, the light spot periodically scanning the web at right angles to the direction of its movement and parallel to its surface, and wherein a light receiving arrangement comprising a rod light guide and at least one photoreceiver is disposed parallel to the web of material and to the direction of scanning. The rod light guide carries a step mirror arrangement on that side of its periphery lying opposite the light inlet, and a light-scattering cylindrical lens grid, the axes of whose lenses extend in the scanning direction, is disposed between the light source and the objective.

Abstract: An apparatus for concentrating light from a linear field on to a relatively small receiver disposed at the end of a rod light guide on the peripheral surface of which light emanating from the linear field is directed. The linear field is arranged substantially at the focal distance from a first concave strip mirror which is disposed so as to extend optically parallel to the field and reflects the incident light from the field to a second concave strip mirror which is optically parallel with the first mirror and forms therewith a substantially telecentric system and which, in turn, reflects the incident light to the peripheral surface of the rod light guide.

Abstract: Apparatus for combining light emanating from a linear scanning field on a relatively small receiver via an optical arrangement producing a scanning light spot with a light ray scanning device onto which a light beam impinges, the arrangement further having optical elements of the transmitting beam of rays located in front of the light ray scanning device, a transmitting concave mirror and a receiving concave mirror extending in the scanning direction, and a cylindrical lens parallel to the scanning field and extending in the vicinity of the latter, the transmitting and receiving beams of rays being separated by pupil separation.

Abstract: Optical apparatus for determining the angle at which light is reflected by a surface being scanned by light spot, wherein in the area of the light beams emanating from the surface is provided a lamellar stepped mirror arrangement which extends in the scanning direction and whose individual planar mirrors are arranged parallel to one another and deflect the light which strikes them to an optical system on whose focal plane is arranged a photo detector array extending at right angles to the optical axis.A particular application occurs in conjunction with monitoring webs of fabric or paper for surface irregularities faults or errors.

Abstract: An optical apparatus for producing a light curtain using a fibre optic rod with a sawtooth mirror disposed along the face away from the curtain area.

Abstract: Optical multiple-reflection arrangement comprising a light source, a lens separated from the source by its focal length in front of a retroreflector which returns a laterally offset beam, deflection means to displace the reflected image to one side of the source, and a second retroreflector near the image, whereby the measurement path between the retroreflectors is traversed at least four times by a beam from the source.

Abstract: Apparatus for the continuous monitoring of the condition of the needle heads of a circular knitting machine which move past a predetermined point one after the other at a definite frequency comprising an illuminating component for producing a light spot in the form of a line situated in the plane of an illuminated needle head without light projecting laterally beyond it, said light spot being projected into an aperture substantially the size of the image of the light spot, a photo-receiver disposed behind said aperture and adapted to emit an electrical pulse signal in proportion to the luminous flux passing through the aperture, and a threshold value electronic device for receiving said signal, which when a pulse falls below a predetermined value and/or when there is a change in the predetermined time spacing of two successive pulses, delivers a warning signal.