Abstract: Apparatus for use in a touch control system capable of recognizing touch positions along a predetermined coordinate axis on a touch surface comprises a substrate having such a surface that is capable of propagating surface acoustic waves and is so characterized that a touch thereon causes a perturbation of a surface wave propagating through the region of the touch. An input transducer coupled to that surface launches a multiplicity of different frequency SAW's along a first path on the surface. A dispersive array of SAW reflective elements formed along a first path on the substrate surface derives a plurality of different frequency wave components from the launched SAW. Each derived component is reflected from a different location along the array. The components are directed across the touch surface in a progression of paths transverse to and intersecting the coordinate axis so that each path corresponds to a component of a predetermined different frequency CODE 13TS.

Abstract: Apparatus for use in a touch control system for a cathode ray tube, display panel or other touch-controlled device which is capable of recognizing touch positions along a predetermined coordinate axis on a curved touch surface comprises a substrate comprising a sector of a three dimensionally curved surface having a touch surface capable of propagating surface acoustic waves such that a touch on that surface causes a perturbation of a surface wave propagating through the region of the touch. An input surface wave transducer mechanically and acoustically coupled to the touch surface of the substrate, upon excitation launches a burst of surface acoustic waves on the touch surface along a first path which represents a great circle on that surface.

Abstract: A method and apparatus for character-by-character magnetic printing on plain paper, using a dot matrix format; a sheet of paper is positioned on the surface of a thin, elongated strip platen of permanent magnet material and a magnetic printhead comprising a columnar array of electromagnets scans the platen. Selective energization of the electromagnets, during each scan, magnetizes dot-size portions of the platen in dot matrix patterns defining magnetic images of the characters in a line of text; limited quantities of toner are applied to the paper generally concurrently with formation of the magnetic images to develop those images as visible characters, which are subsequently fixed on the paper surface.

Abstract: A fraction collector includes a rack-holding tray mounted on a base which houses a drive mechanism for actuating rack shifters, the tray carrying twelve three-test-tube racks or twenty five-test-tube racks in two staggered rows. A rack adapted for carrying n test tubes is provided on a bottom side with n projections spaced along the length of the rack by a distance equal to the quotient of the rack length divided by n, the projections coacting with shifters in the form of vertically extending fingers reciprocatably mounted at opposite ends of the base for pushing racks in n incremental steps from one row to another. Each rack further includes a pair of additional projections for cooperating with two row shifters to push a row by one rack width upon the transfer of a rack to this row from the other row; these additional projections are spaced by pre-established distances from the long sides of the racks to facilitate the movement of a rack row by exactly one rack width.

Abstract: A driver mechanism for a dot matrix printhead, including an electromagnet, an armature, and a print impact element connected to the armature by a cantilever spring, energization of the electromagnet and consequent movement of the armature to closed position driving the impact element to impact a record sheet supported on a platen; a concentrated mass load is mounted on the spring, sufficient to maintain the impact element essentially in its rest position during a substantial portion of the armature movement so that the force/travel characteristic of the spring governs movement of the impact element, with maximum force at the outset and near zero or zero force at impact. Energization of the electromagnet is interrupted when the armature closes, and a shunt circuit holds the armature closed until just before impact.

Abstract: A matrix of four photoreceptors is arranged to develop output signals representing information stored in a video disc as well as error signals for maintaining proper tracking registration of the reading beam with the storage track of the disc. The matrix enables all four photoreceptors to contribute to the development of the output signals and permits separate treatment of high frequency and low frequency signal information for improved results with respect to response and signal-to-noise ratio.

Abstract: An elasto-optic device for providing periodic lateral displacement in a radial tracking servo system for a video disc player. A transparent prism is vibrated in either a flexural or a second harmonic extensional mode by a thin piezoelectric ceramic platelet attached to a side of the prism and energized by an oscillatory signal. Vibration occurs at a natural mechanical resonant frequency of the prism, and a linear strain distribution is established in the prism at its intersection with the path of the optical beam used for reading the record track. The substantially linear strain distribution effects a corresponding localized periodic change in the index of refraction of the prism material to provide lateral optical beam deflection without the use of moving parts.

Abstract: An optical video playback device has an optical system for reading discs with a laser and further has a self-compensating focusing feature. This avoids the need for focus servos and the like to maintain proper conditions of focus.