Abstract: A method and apparatus are shown for precision distance or displacement measurement using a light source and a detector. A light emitting diode or laser are typical sources, and a photodiode or phototransistor are typical detectors. Light from the source is directed towards the detector directly, or reflected onto the detector by a reflective surface. By tilting the axis of the light source and detector, high sensitivity is possible. The effect of the tilted axes may be obtained by the use of two reflective surfaces. Typical resolution is on the order of 5 microinches over a range of 50,000 microinches (i.e., one part in 10.sup.4) using simple associated electronics, with higher resolution possible.

Abstract: A method and an apparatus for determining the location of a piece of timber having a flat top surface and two unfinished side surfaces or determining the width and location of its flat top surface is described. The piece of timber is subjected to radiation in such a manner that the top surfaces and the side surfaces are simultaneously subjected to radiation of different wave length. Light may be used as the source of radiation and rays of different wave length are reflected from the piece of timber and are separately detected by means of a light sensitive element.

Abstract: A flat panel display device having a plurality of electron propagation channels utilizes a line cathode. The cathode extends across all the channels and modulation electrodes associated with the channels cause the cathode to emit the electrons into the spaces between parallel guide meshes within the propagation channels. The cathode and modulation electrodes are arranged in a recessed cavity in the proximity of launch electrodes so that the electrons are emitted at high velocity into the propagation channels to travel curved paths along which the electron beams are converged into the spaces between the guide meshes. Electron propagation structure within the channels, therefore, is displaced from the cathode so that the cathode heat has a substantially reduced effect on the propagation structure, and the high electron velocity minimizes the effect of mechanical tolerances on the electron beam.

Abstract: An economically manufacturable self cleaning spark plug which utilizes combustion gas flow effectively to keep the tip of the plug clean and retains gap spacing indefinitely thereby assuring long spark plug life.

Abstract: A backward-wave Raman amplifier or pulse compressor for compressing laser pulses. A laser pulse, or pump beam, of relatively long duration enters one end of the compressor. A short, initiating Stokes-Raman pulse enters the other end of the compressor and absorbs energy from the pump beam as the Stokes-Raman pulse traverses the compressor. The cross-sectional area of the Stokes-Raman pulse within the compressor increases linearly with distance traversed through the compressor so that the energy density within the pulse remains substantially constant as the pulse traverses the compressor and receives energy from the pump beam which traverses the compressor in the opposite direction. The cross section of the pump beam also varies linearly with distance within the compressor so as to coincide substantially with the cross section of the Stokes-Raman pulse and thus achieve efficient compression.

Abstract: The present invention relates to an apparatus for providing second harmonic generation from a single beam in an isotropic medium. An isotropic medium having a two-photon transition between a first level and a second level with a quadrupole moment therebetween is exposed to a beam of laser radiation. The photons in the laser beam have an energy which is substantially equal to one-half the energy difference between the first and second levels.

Abstract: An apparatus for reading information and converting it into digital data comprises an illuminating means which illuminates a source document (10), an optical system (12) which enables light from different parts of the document to be focussed at a photoelectric detector (14) and a deflection system (13) which directs light from different parts of the document (10) into the detector (14). The optical system (12) comprises a concave lens which converts the source document into a smaller, curved image which can be scanned by the apparatus, and a doublet lens with two elements whose separation is varied by a control device (16) so as to compensate for variations in the distance of the document from the detector (14). The deflection system (13) is also directed by the control device (16) which may cause it to follow lines on the document (10) or to perform a raster scan. Signals from the detector (14) are passed to a signal processor (15) which converts them to digital form.

Abstract: The invention relates to automobile sealed-beam headlamps in which a reflector and lens assembly are hermetically sealed by an epoxy resin. A pressure relief hole in the reflector eliminates the problem of excessive expansion and contraction of the atmosphere within the lamp such as would prevent forming a hermetic seal between the reflector and lens during the epoxy resin curing cycle. A deformable metal pellet forms a hermetic seal in the pressure relief hole. An epoxy resin is applied over the deformable metal seal and cured to produce a final permanent seal.

Abstract: An alignment device of a type, wherein an alignment pattern provided on a mask for fabrication of a semiconductor circuit element and an alignment pattern provided on a wafer are photoelectrically read in a dark field by a flying spot scanning system or a flying image scanning system to detect a relative positional relationship between the mask and the wafer, and a desired positional relationship is obtained by moving at least one of the mask and wafer on the basis of a detected signal. The novel feature of this alignment device resides in that the size of a line forming the alignment pattern along the scanning line is twice or more as large as the size of the scanning spot.

Abstract: An array camera used to scan elongated workpieces moving through a measuring zone transversely to their lengths has its photoresponsive detector elements aligned lengthwise of the workpieces, with optical axes of the elements lying in a common plane intersecting the measuring zone. Each element "sees" only a small (e.g., 8.times.8 mm) pixel. Radiation sources are located at opposite sides of said plane and emit radiation towards the measuring zone to be reflected to the elements from workpieces. During each of a succession of short measuring cycles (e.g., 4 millisecond duration) each element is exposed successively to radiation originating from each radiation source to the exclusion of the other, to thus produce an A output and a B output during each cycle, and is also exposed to substantially low level radiation to produce an R output. For each cycle, the R output of at least certain elements is subtracted from the A and the B outputs of the same elements for the same cycle, to produce .DELTA.A and .DELTA.

Abstract: A luminescent screen consisting of one self-supporting monocrystalline body and having a luminescent surface layer with V-shaped grooves. Such screens may be exposed to radiation having a larger energy than was usual so far with phosphor screens and have a very large luminous efficiency. In addition the resolving power is very large since there are no particles with limiting dimensions. Such screens may be used for displaying very bright pictures suitable for projection on a projection screen.

Abstract: The present invention is an improvement in a multi-beam electron gun for use in a cathode-ray tube. Such gun includes a plurality of cathode assemblies and at least two spaced successive electrodes having aligned apertures therein. The improvement comprises the cathode assemblies and the two electrodes being individually attached to a single ceramic member. The ceramic member is the sole supporting interconnection within the gun between the cathode assemblies and the two electrodes.

Abstract: A fluorescent display device is disclosed having a grid which is divided into several pieces electrically separated and disposed in close proximity and in an opposed relationship at the edges thereof. The grids are held in position within the display device by an elongated insulator which bridges the respective opposed edges of the grids and a sealing portion around the periphery of the display device.

Abstract: A laser inspection system is provided having an absolute closed loop dc system in which the power gain is automatically stabilized. In order to stabilize the power gain of the system and provide a closed loop absolute reference dc level, a sample of the radiation from the laser beam utilized to scan the material being inspected is applied to a photomultiplier tube for generating a reference pedestal signal which is dependent on the intensity of the laser beam and is free of the influence of the characteristics of the material being inspected. The reference pedestal signal is applied to a comparator which develops a control signal which is applied in a single closed feedback loop including in effect, the laser source and the light collection and detection system within the loop. This loop includes the photomultiplier tube and its high voltage power supply to which the control signal is applied for stabilizing the gain of the system.

Abstract: A U-shaped device wherein the presence or absence of a transparent liquid or solid between the legs of the U is sensed. The device utilizes a collimated light source mounted in one leg of the U with an associated limited field of view sensor in the other leg of the U-shaped device. The light source is placed so as to cause the transmitted light beam to strike the surface of the material to be sensed at an angle which is substantially off of a line perpendicular to the surface of the sensed material.The light sensor is placed so as to receive the light beam when there is no liquid or solid material present between the source and the sensor and to prevent the refractively bent light beam from striking the sensor when a transparent liquid or solid is placed between the light source and sensor.

Abstract: An angular position transducer for a rotating member comprising a notched disc connected to said member, an opto-electronic pair for sensing the angular position of said disc and a supporting shell for said pair which is fixable on the support of the rotating member coaxially to said member. The disc is fixable directly to the rotating member at a predetermined position with respect to the shell, and comprises a thin flexible lamina guided on its periphery by a guiding element adjacent to the notches. The flexibility of the lamina compensates for any disalignment and axial displacement of the rotating member. The position signal is periodic and is sent to the terminals of a reference resistor. A control circuit modifies the value of the resistor in order to stabilize the peak value of the position signal within predetermined narrow tolerance limits.

Abstract: The wavelength of an optical pump beam is down converted to a longer wavelength in a Raman active gaseous medium by stimulated Raman scattering. The Raman active gaseous medium is contained in the space between a pair of optical reflectors of an optical resonator of the type for producing a focus of the optical beam energy at a point intermediate the length of the resonator within the Raman active medium to enhance conversion of pump energy into the output longer wavelength of the Stokes wave. The pump beam is directed into the optical resonator at an angle to the optical axis of the optical resonator such that the optical beam path is folded back and forth within the optical resonator to cause the beam spot to walk over the surfaces of the reflectors and out of the optical resonator.

Abstract: An electron gun structure which includes at least one cathode electrode, a plurality of grid electrodes including a first grid electrode, and a heater coil. The cathode electrode consists of a tubular cathode sleeve and an electron emissive coating formed on the closed end of it. The heater coil is positioned within the cathode sleeve and has legs welded to the heater supporting straps. The surfaces of the heater straps adjacent cathode sleeve are constructed such that the arcing start potential between the cathode electrode and the heater supporting straps is lower than the arcing start potential between the cathode electrode and the heater coil, thereby preventing arcing to the heater itself.

Abstract: A paint application method with manual or automatic guidance of the spray gun at a constant distance from the working surface in the zone of picture reproduction, with the amount of sprayed paint controlled by the intensity of a light beam guided by a picture pattern. The light beam strikes a photocell cooperating with a control element of the spray opening of the spray gun, the photocell or/and the picture pattern being moved synchronously with the guide movement of the spray gun. With manual guidance of the spray gun, the light beam may be a projection beam which projects the picture pattern on the working surface. The spray opening may be guided automatically row for row over the working surface.

Abstract: The inclusion of an alkali metal halide in the gas fill of a high pressure mercury and aluminium halide discharge lamp improves the color appearance of the lamp; notably by lowering the color temperature, while maintaining or even increasing the efficacy and stability of the discharge. Preferred contents are 10 to 30 mg cm.sup.-3 mercury, 5 to 100 .mu.mol cm.sup.-3 aluminium halide and 0.5 to 150 .mu.mol cm.sup.3 alkali metal halide, with the molar ratio of alkali metal halide to aluminium halide in the range 0.1 to 1.5 and the total number of aluminium and alkali metal atoms preferably greater than the total number of halogen atoms.