Abstract: Disclosed is a system for monitoring and controlling movement of a hoist along a line of treatment tanks of an electroplating apparatus. Hoist-mounted optical sensing units of the system have pickups formed of opposed lines of infrared emitting diodes and phototransistors which interact with elements of plates fixed at work stations along the tanks to provide station identification and centering information relative to the hoist. A microprocessor-based controller on the hoist processes data from the sensing units and from a rotary encoder attached to a hoist drive motor and, under direction of an off-hoist main computer, rapidly and accurately positions the hoist at selected stations in a desired operating sequence.

Abstract: The invention relates to a method and an apparatus for calibrating a positioning system including a control computer (1405) for producing command value signals to a positioning apparatus which positions an object against a work surface. Sensors (1406,1407) detect the location of the positioning system and convert it to an actual value signal which can be fed back to the control computer. A calibration plane (601) placed on the work surface contains a number of calibration points (602,603), the command value positions of which are entered into the control computer. The positions of at least some calibration points are sensed by a calibration probe (605) corresponding to the object and the actual values for the positions of said points are compared with the command values for the positions of these points on the work surface entered into the control computer.

Abstract: A collision sensor and compliance device for use with computer controlled robotic arms adapted to have a robotic hand disposed on the distal end thereof includes a housing affixed to the robotic arm on one end with a robotic hand affixed upon the other end thereof. The front and rear walls of the housing includes triangular-shaped apertures disposed in a common plane with the apex of each of the triangularly-shaped apertures being positioned equally distant from the lower edges of each of the walls. Light emitting diodes are centrally disposed in one pair of the oppositely disposed walls with photoelectric light sensors disposed in the robotic hand support bracket. The robotic hand or support bracket includes at least a pair of bearings (preferably two pair) disposed at right angles to each other and adapted to be received and cooperate with a pair of the triangularly-shaped apertures provided in the housing.

Abstract: A numerical control system in which data signals are exchanged between a computer processing device MPU and each function block through an address bus ABUS and a data bus DBUS. Parallel electric signals are converted into serial signals by shift registers SHR.sub.1 and SHR.sub.2, and are converted into light signals by transmitters Tx.sub.11 and Tx.sub.12. The light signals are delivered to pulse distributors PDN through optical fiber cables OF.sub.1 and OF.sub.2 and these light signals are converted back to electric signals by receivers Rx.sub.3 and Rx.sub.4 and are further converted into parallel signals by shift registers SHR.sub.3 and SHR.sub.4. The parallel signals are delivered to a pulse distributor PD as position signals in the directions of X, Y and Z axes thereby to driving servomotors.

Abstract: A computerized stage assembly for a Scanning Electron Microscope including a support frame, a tilt frame pivotally coupled to the support frame, an X carriage engaged with the tilt frame for movement in an X direction, a Y carriage engaged with the X carriage for movement in a Y direction, and a pedestal carried by the Y carriage and capable of rotation around an axis substantially normal to both the X and Y directions. The tilt frame, X and Y carriages, and pedestal are moved by computer controlled step motors. The tilting and rotating of a specimen secured to the pedestal is non-eucentric, i.e. the axis of rotation or tilt is not necessarily through the point of inspection on the specimen. A method is disclosed for automatically returning an inspection point to the viewing field of the microscope after a non-eucentric rotation or tilt.

Abstract: A position detecting apparatus provided with a lighting unit 13 for lighting an object 14 to be detected, an image-formation unit 15 for imaging the object 14, a detecting unit 16 comprising a plurality of photoelectric converters disposed on the image-formation plane to detect brightness of the image and disposed two-dimensionally, a scanning unit 17 for allowing the relative position of the image to the photoelectric converters to move one-dimensionally in the image-formation plane, a selecting unit 19 for selecting the plurality of detected signals of the detecting unit, and a decision means 18 for deciding the one- and two-dimensional positions of the center, corner and edge of the object by means of the detected signal of the detecting unit, a selected signal of the selecting unit and a scanning signal of the scanning unit, so that the images formed are moved slantwise with respect to the plurality of photoelectric converters disposed two-dimensionally and the selecting unit selects the detected signals

Abstract: The radial position of a transducer used to read and/or write information into or write information into or from a spinning information storage disk (optical or magnetic) is servo controlled by an optical doppler interferometer mounted at least in part for common movement with the transducer. The optical doppler interferometer measures the instantaneous linear velocity of the information storage disk at the position of the transducer (or at a fixed relative position with respect to the transducer) and the position of the transducer is controlled so as to make the measured instantaneous linear velocity follow a reference signal corresponding with the desired information storage track.

Abstract: A controller for a tracking system which tracks the sun. The controller has a rotatable disc with a light transmitting portion and an opaque portion. The solar radiation, transmitted through the disc when rotating, falls on optically sensitive sensor detecting the light intensity. Two optical emitter/receiver pairs which are oriented with respect to two coordinate axes at the periphery of the disc detect the position of the light spot on it. The solar radiation is directed by the rotating disc to generate two signals which are related to the two coordinate axes and the tracking error of the tracking system. The signals energize motors in the tracking system whereby the sun is tracked.

Abstract: A slot detecting apparatus comprises a sensor for detecting a slot of a workpiece, comparators, and a discriminating circuit. The sensor moves over the workpiece so as to traverse the slot and produce an output having a waveform which is substantially an M-shape. The comparators compare the level of the output of the sensor with a plurality of threshold levels which are mutually different, and each produce a comparison result for each of the plurality of threshold levels. The discriminating circuit discriminates the position of the slot based on a comparison result which indicates that the output of the sensor has a waveform which is substantially an M-shape, from among a plurality of comparison results which are obtained from the comparators for the plurality of threshold levels.

Abstract: A torque-sensing rotary tool for use in bottle-capping, and other such applications. The tool (10) is characterized by independent motors (30 and 40) means for gripping and rotating bottles or the like and a rotation-counter which forms means, with associated circuitry (FIG. 9), to determine when an object, e.g. a bottle cap, may be safely lifted by automatic machinery, e.g. by robot means.

Abstract: X-Y position measurement apparatus is employed with feedback controlled X-Y positioning apparatus for positioning a workpiece stage at a desired X-Y coordinate position in response to signals indicative of the actual position and the desired position of the workpiece stage. A normalization circuit is employed for gain correction of the signals indicative of the actual position of the workpiece stage.

Abstract: The method of inspecting and determining the status of a hole in a surface of a part comprising placing a robot at a stationary position, said robot being controlled by a programmable controller and having a movable arm with a fiber optic scanner device capable of sensing a reflective surface. The part to be inspected is placed in a stationary fixture spaced from the robot and the robot arm with the fiber optic scanner device is moved to a point spaced from the part surface. The robot arm with the fiber optic scanner is incrementally moved closer to the part surface until light reflection is detected from the part surface by the fiber optic scanner. A signal is sent to the robot controller upon detecting light reflection from the part surface to stop further incremental movement of the robot arm and fiber optic scanner closer to the part.

Abstract: A precision machining system for machining a workpiece into a desired surface with two tool driving units. A first drive unit moves the tool along at least two axes to shape the workpiece similar to a desired surface. A second drive unit moves the tool along one of the axes in a very finely controlled manner. A measuring unit measures the tool position with an accuracy higher than that to which the first drive unit can respond. A signal producing unit is responsive to the measuring unit for producing a control signal for controlling the operation of the second drive unit while the first drive unit is operating.

Abstract: A method and a device for inputting the coordinates of a robot acts so that the coordinates are input accurately by scanning the working area of the robot and inputting, as coordinates of the working position, positional data when a sensor has detected the working position. A movement data calculator (138) receives target position data from a preteaching data area (146), operates a pulse register (130) and drive circuits (152), (154), (156), and makes the sensor positional data in a position register (130) coincide with the target positional data. It then receives positional vector data from a plane scanning data area (148) and a vertical scanning data area (150) and scans the sensor over the working area.

Abstract: A system and method are disclosed for precisely positioning a movable member to a desired fine position after a selected coarse position is reached. In a preferred embodiment of the invention a processor-controlled typewheel servo control system is responsive to a command signal for a selected coarse position for selectively utilizing from a memory circuit preselected stored adjustment information for the selected coarse position comprised of an associated coarse position count and quadrant information related to the sinusoids generated by an optical encoder in order to make a precise fine position adjustment in the position of a typewheel after the selected coarse position is reached for that typewheel.

Abstract: A mask feed method and apparatus for deeding and setting with a high degree of positional accuracy a circuit pattern printing mask in a proximity exposure replicate system for printing integrated circuit patterns on a semiconductor wafer. Arranged on the same stage but separated from a wafer chuck is a mask station on which a mask is set a position different from the exposure position and fed to a mask holder at the exposure position for mask feeding purposes. The mask station is provided with its own displacing means for aligning purposes.Thus, the required movements for mask feeding and alignment purposes are effected by a wafer transfer mechanism.

Abstract: A light valve has a pair of rotating vanes for controlling the cross section of a light beam passing between the vanes. The vanes rotate on corresponding shafts, each controlled by its own integral motor. Separate feedback control systems produce electrical control signals to each motor for rotating each shaft independently of the other to control the desired phase angles of the vanes. In one embodiment, both motors are permanent magnet direct current servo motors in which the wound armature is an integral part of each shaft. A stationary magnetic field generated by permanent magnets is common to both motors. Power is supplied to each armature by a pair of thin, parallel, flexible, electrically conductive strips extending from an end of each shaft. The conductive strips reduce the torque on the shaft when twisted during operation. In one embodiment, the control system produces a calibrated digital control signal from a PROM representing the desired phase angles of the rotating blades.

Abstract: In effecting positioning of a workpiece relative to a working tool, indexing is carried out by obtaining precision measurement of the relative distance between the workpiece and the working tool by using a laser beam. Positioning can be effected with improved precision and working can be achieved with improved dimensional accuracy.

Abstract: A two axis joystick controller (14) produces at least one output signal in relation to pivotal displacement of a member (32) with respect to an intersection of the two axes. The member (32) is pivotally movable on a support (42) with respect to the two axes. The support (42) has a centrally disposed aperture (46). A light source (34) is mounted on the pivotally movable member (32) above the aperture (46) to direct light (47) through the aperture. A light sensor (48) is mounted below the aperture (46) in the support (42) at the intersection of the two axes to receive the light (47) from the light source (34) directed through the aperture (46). The light sensor (48) produces at least one output signal related to a location on the sensor (48) at which the light (47) from the light source strikes the sensor (48). The two axis controller (14) is small enough in size to be mounted on another, hand-operated X-Y controller (10) for thumb operation by a hand positioned to operate the other X-Y controller (10).

Abstract: A continuous drive type Michelson interferometer system for use in Fourier spectroscopy, having a main Michelson interferometer for obtaining the interferogram of a sample, an auxiliary Michelson interferometer for detecting the moving speed of a movable mirror of said main Michelson interferometer, and a control section for controlling the driving speed of said movable mirror. In said control section, the AC output signal of a photodetector is converted into a voltage corresponding to the frequency of the signal, said voltage is compared with a preset voltage by a voltage difference detection means, the phase of said AC output of said photodetector is compared with a phase of a reference signal by a phase comparison means, and said driving speed is controlled by both the outputs of said voltage difference detection means and said phase comparison means.

Abstract: In an incremental measuring instrument for measuring the relative position of two objects, of the type including reference marks absolutely positioned with respect to a graduation of a scale, a first scanning plate with scanning fields for the graduation is provided in a scanning unit which is shiftable on a guide independent of the guide of the objects to be measured. The second scanning plate is connected to the first scanning plate by means of a coupling which is rigid in the measuring direction. In this way the separation of the first and second scanning plates with respect to the scale can be adjusted independently for optimal scanning of both the graduation and the reference marks.

Abstract: An automatic control system for controlling the operation of a sliding door system employs an electric motor for driving the sliding door system. An encoder is mounted to the shaft of the motor for generating signals which are decoded to detect the operational position of the sliding door system. A clock paced sequential logic circuit produces speed and directions signals in accordance with the detected operational position to control the speed and direction of the electric motor. Means are provided for recording the last stop position and slowing the sliding door system prior to reaching the last stop position. Safety means are provided to de-energize the motor in the event of malfunction of the motor speed control. The system also includes a reduced opening stop feature and a means for automatically establishing a sliding door reference position.

Abstract: A robotic positioning system is provided which comprises a base portion; a plurality of interconnected arm members mounted on the base portion and having respective axes of movement; a hand member carried at a distal end of the arm members for supporting a functional member; a plurality of drive means associated respectively with the plurality of arm members and operable by respective drive signals for moving the arm members along the respective axes so that the functional member reaches a target spacial position and there assumes a target spacial orientation; and a gyro assembly having a frame mounted for joint movement with one of the members and a rotor supported in the frame to rapidly spin about an axis set to orient in a predetermined direction, which is invariable relative to the base portion, whereby to provide a directional reference for monitoring a spacial orientation assumed by the one member upon a movement along the corresponding axis of movement.

Abstract: A reference post assembly (50) directly mounted on a numerically controlled machining system such as a lathe obviates the need for a datum ring including reference datum surfaces (42,44) and being conventionally provided on the external cylindrical surface and face of a chuck (36) which holds the workpiece (41) being machined. The reference post assembly (50) is comprised of an elongated reference post member (52) of selected cross section, i.e., square or round, which is resiliently mounted on the lathe in a known calibrated position with respect to the workpiece (41). The post (52) is ultrasonically vibrated in a longitudinal mode by one or more piezoelectric elements (54) coupled to an electrical signal oscillator (56).

Abstract: The present invention relates to an apparatus for controlling a moving object and particularly for automatically stopping the moving object in a predetermined position and direction. The apparatus comprises a pair of photoelectric sensors having a light emitting element and a light receiving element for the moving object, and a pair of reflectors at predetermined positions opposing the photoelectic sensors. The moving object is stopped when the received light outputs of the photoelectric sensors are balanced with each other preferably in a vehicle in an automated factory.

Abstract: A low cost servo operated digital positioning system which utilizes a phase shift control circuit in combination with an encoder and servo circuit for driving a moveable element. The encoder generates a pair of signals A which may be equivalent to a sine signal A and a cosine signal A. The phase shift circuit multiplies signals from the encoder by a sine of a demand signal B and by a cosine of the demand signal B and produces a sine (A+B) signal and a cosine (A+B) signal. These sine and cosine shift signals are introduced into a servo circuit for control of a moveable element. By phase shifting these signals it is possible to substantially increase the overall number of positions to which a moveable member may be moved and thereby substantially increase the overall accuracy of a positioning system.

Abstract: This precision probe uses optical feedback in the X and Y dimensions to locate a microprobe in the airspace over a test pad, and uses pressure feedback in the Z dimension to control Z approach and penetration. The precision probe inspects a target by coarse positioning a guided microprobe to make contact at a selected probe pad. Guidance is optical, by light reflected, from a target by a dual mirror focusing system of concave mirror and flat mirror, to a transducer. Up and down Z positioning of the microprobe is carried out by a shaft positioned by an air diaphragm which is driven to the target by applied air pressure delivered via an air tube, providing the desired penetration of microprobe to microtarget. The probe is retracted by atmospheric pressure.

Abstract: A compressor arrangement for a heat pump installation in which an electric motor is provided as the drive means for the compressor is disclosed. In order to make possible operation of the compressor without unpermissibly large surge currents in the electric network supplying power to the electric motor, the compressor is driven by a permanent magnet-excited d-c motor which is provided with an electronic commutating device. The starting current drawn by the d-c motor can be controlled by means of a d-c voltage control element coupled to the electric network by a rectifier so as to prevent unpermissibly large starting surge currents.

Abstract: Mounting a position sensor equipped planar armature, in operative juxtaposition to a stator, by a spring colonnade basket of flexure columns, provides a low-friction precision X-Y-Theta positioner which has computer control of operations with feedback of actual position for closed loop servo operation.The spring colonnade basket provides freedom of motion in the X, Y and Theta (rotation about an axis mutually perpendicular to X and Y) dimensions without static friction present in sliding or rolling motions. The armature, which carries a gripper or other end effector and is free to move only within its own plane, is positioned by a motor made up of the armature and a stator mounted on a support platform. The stator is made up of a pair of U-shaped permanent magnets, each having U-shaped pole pieces mounted orthogonally to each other, at 45 degree angles to the axis of the magnet, so that each electromagnet controls motive power in both X and Y dimensions.

Abstract: Suspending an armature on a parallelopiped basket of flexure springs, with a lateral effect cell position sensor and an X-Y source of motive power, provides a precision X-Y positioner with minimum static friction and with feedback of actual position for closed loop servo operation under computer control. The armature is arranged for X-Y motion within its own plane, and is arranged to carry a gripper, cutting tool, or other end effector. The parallelopiped basket includes a stator, a first set of flexure springs, a flexure spring carrier mounted on the first set of flexure springs, a second set of flexure springs mounted on the flexure spring carrier, and the armature mounted on the second set of flexure springs in turn mounted on the carrier. The basket suspends the armature with freedom of motion in the X and Y dimensions without static friction associated with sliding or rolling motions.

Abstract: A brushless linear servomotor utilizes a first member provided with magnetic teeth having a large number of teeth-salients and slots arranged lengthwise of the first member at regular pitches and a second member which is moveable along the first member and has at least one magnetic core with magnetic teeth groups engraved thereon at surfaces opposite to the first member, and having a coil wound around each of the magnetic cores and further having a guide arranged to keep a constant gap between the first and second members. A number of non-contact detectors are connected to the second member so as to detect the salients and slots of the magnetic teeth of the first member. An electronic commutator and an electronic scale circuit are both connected to the non-contact detectors.

Abstract: This invention is directed to electromagnetic alignment apparatus, which is particularly adapted, among other possible uses, for use in aligning the wafers in a microlithography system, said apparatus comprising in combination a first magnetic circuit having a plurality of elements including a first magnet; a second magnetic circuit having a plurality of elements including a second magnet; the second magnetic circuit being disposed in spaced relationship with respect to the first magnetic circuit; a movable structural component adapted for mounting an object thereon; one element of each magnetic circuit being fixedly attached to the movable structural component; first and second current carrying coil assemblies mounted in the first magnetic circuit; the second coil assembly being disposed at an angle with respect to the first coil assembly; third and fourth current carrying coil assemblies mounted in the second magnetic circuit; the fourth coil assembly being disposed at an angle with respect to the third coi

Abstract: The position adjusting drive unit for a sewing machine having its work shaft driven by an electromotor with an adjustable rotary speed, includes a supporting box connected to the electromotor and including a power supply transformer and an activation mechanism for a signal generator for desired and actual values of the rotary speed of the motor and of the angular position of the working shaft; an exchangeable printed circuit board supports all electrical and mechanical component parts of the speed regulating and angular position adjusting circuits including the signal generators and the coupling rod between the activation mechanism in the supporting box and the part of the activation mechanism on the circuit board is guided into the proper coupling position when the circuit board is electrically connected to the power supply transformer.

Abstract: This invention is directed to electromagnetic alignment apparatus, which is particularly adapted, among many other possible uses, for use in aligning the wafers in a microlithography system, said apparatus comprising in combination three or more spaced magnets, three or more coil assemblies mounted to pass through the magnetic fields of the magnets respectively, means for controlling the flow of current through the coil assemblies respectively, said coil assemblies being joined together to form a structure movable with respect to the magnets and adapted to carry an object thereon, the coil assemblies being wound with respect to each other so that by controlling the supply of current to the coils the structure can be moved selectively in three degrees of freedom.

Abstract: This invention is directed to electro-magnetic alignment apparatus, which is particularly adapted, among many other possible uses, for use in aligning the wafers in a microlithography system, said apparatus including in combination at least three magnet assemblies which are mounted in space relationship one with respect to the others, at least three coil assemblies mounted to pass through the high flux region of the magnet assemblies respectively, the width of the coil assemblies being substantially less than the width of the high flux regions respectively, a controller for controlling the flow of current through the coil assemblies respectively, a structural assembly for connecting the coil assemblies which is movable with respect to the magnet assemblies, the coil assemblies being wound with respect to each other so that by controlling the supply of current to the coils the structure assembly can be moved selectively in three degrees of freedom.

Abstract: This invention relates to a circuit arrangement and the associated mechanism for slaving the angles of rotation of the slats of a plurality of centrally controlled sun or window blinds. The driving motor of each blind is provided with current via a corresponding operational amplifier and related circuit. The motor operates the slats to achieve balance between an input control voltage and a voltage depending on the angular position of the slats. An automatic version in which the control voltage is generated by a photoelectric sensor and several circuit variations are shown.

Abstract: A safety system and method for industrial robots includes a detection arrangement having a detection field covering the area of reach or operation of the robot. Detection data obtained through the detecting arrangement in each of predetermined operation positions of the robot is compared with the detection data indicative of the normal or correct detection field in the same operation position. The movement of the robot to the next operation position is prohibited when a difference of a level exceeding a predetermined level is obtained during the comparison.

Abstract: This invention is directed to electro-magnetic alignment devices, which are particularly adapted, among other possible uses, for use in aligning the wafers in a microlithography system, said devices comprising in combination a base plate, a first current carrying coil assembly mounted on the base plate, a second current carrying coil assembly mounted on the base plate in spaced relationship with respect to the first coil assembly, a first magnet mounted adjacent the first coil assembly and a second magnet mounted adjacent the second coil assembly, an upper connecting piece connecting the first and second magnets, a mount for receiving an object on the upper connecting piece, the base plate and magnets and upper connecting piece coacting to form a magnetic circuit, a controller for controlling the flow and direction of current through the coil assemblies to move the magnets and upper connecting piece with respect to the base plate, a plurality of linear actuators mounted between the magnets and the upper conne

Abstract: A servocontrol permits the alignment of a slave mechanical component with a master mechanical component. A probe measures its distance from the master component and another probe measures it distance from the slave component. A circuit processes a square wave pulse whose duration is proportional to the distance separating the master component from the slave component. A motor is supplied with power until the pulse ends.

Abstract: A multi-lead component manipulator for the assembly of circuit boards has optical and tactile feedback systems and includes at least two and preferably three symmetric assemblies radially disposed about a component gripper assembly. Each symmetric assembly has a movable lead guide means for engaging a component lead and aligning the same for circuit board insertion. The guide means are adapted for independent arcuate and radial motion reflective of the optical feedback system and the gripper assembly is capable of axial movement for the acquisition and insertion of components. The tactile feedback system controls component insertion. The manipulator in an alternative embodiment has fixed guide means disposed above the movable guide means. The fixed guide means orient the component leads for acquisition by the movable guide means.

Abstract: Wafer alignment apparatus includes an aligner platform having defined thereon X and Y axes and a desired rotational orientation for a wafer. A first vacuum spinner is supported for rotation in the platform about the intersection of the X and Y axes and second and third spinners are provided displaced from the intersection of the axes. Two edge sensors, for sensing the desired wafer edge location at two points separated from each other, and edge or notch sensors for sensing rotational alignment of said wafer provide inputs to logic means which provide outputs to the vacuum spinners for carrying out a series of individual rotations to align the wafer.

Abstract: A linear motor shuttling system for shuttling the print head (11) of a dot matrix line printer is disclosed. The print head (11) is supported by a pair of flexures (13, 15) such that the head is free to move back and forth along a print line. One end of the flexure supported print head is attached to the coil (31) of a voice coil linear motor (23). The linear motor (23) is also flexure (27, 29) supported. The linear motor (23) is positioned such that the axis of coil movement is co-axial with the axis of movement of the print head (11). Further, the resonant vibration frequency of the combination of the linear motor and the linear motor flexure support is tuned to the resonant vibration frequency of the combination of the print head and the print head flexure support.

Abstract: Movable (a head) and stationary (a stator) members are disposed in contiguous relationship. First magnetizable and non-magnetizable zones are alternately disposed on the stator in a particular direction. Second magnetizable and non-magnetizable zones are alternately disposed on the head in the particular direction. The zones on the head and the stator face each other and have substantially equal spacings. First means are associated with the head for producing magnetic fluxes in the magnetizable zones in the head and stator in a particular pattern to obtain incremental relative movements between the head and the stator on a vectorial basis in the particular direction. Second means are associated with the head for compensating for hysteresis effects in the magnetizable zones in the head and stator. The second means may produce magnetic flux of alternating polarity and decaying amplitude near the end of each incremental movement of the head relative to the stator.

Abstract: Apparatus for precise positioning of a movable stage such as a microscope stage including a light source and a self-scanning array of photodiodes for receiving light from the light source. An opaque shade is adapted to be moved with the shade and block at least a portion of the light which otherwise would impinge on the self-scanning photodiode array. The self-scanning photodiode array is adapted to emit an electrical signal proportional to the number of photodiodes on which light impinges. A digital comparator is adapted receive this signal in digitized form and compare the same with a positioning program digital input. In the event of a difference a responsive signal is emitted to a bi-directional motor drive which effects corrective movement of the stage. The apparatus may also function as a tachometer.

Abstract: In an X-Y addressable workpiece positioner, the workpiece to be positioned, such as a semiconductive wafer to be sequentially exposed at different regions thereof in accordance with a pattern of a mask, is disposed for movement with a work stage along coordinate X and Y axes. The work stage has a two-dimensional array of X and Y coordinate addressing indicia enclosed within a border and affixed to the work stage for movement therewith. A portion of an enlarged image of the array of addressing indicia is projected onto a sensor stage to derive an output indicative of the X and Y coordinates of the array of addressing indicia relative to the position of the sensor stage. The X and Y coordinates of the array of addressing indicia are sensed through addressing indicia recognition windows of the sensor stage and are differentially compared to remove unwanted background effects.

Abstract: An automatically controlled plotter that generates graphic information on recording material in response to a plot program includes an optical sensor for detecting the traces or lines that are generated in the plot on the recording medium. The detected lines are compared with the programmed lines to establish if an omission or gap exists, and where there is a gap, the plotting process is interrupted or the program is repeated to retrace the defective portion of the plot, or the defect can be recorded for subsequent correction.

Abstract: A digital positioning system having high accuracy is disclosed, which employs an incremental position optical encoder as the position transducer. In response to the output signal from the encoder, the system provides coarse and fine position signals which are combined to form a composite digital signal representing the absolute position of a moveable control member. The composite position signal has a resolution of greater than one part in one million. Trigonometric conversion techniques are used to derive high resolution incremental position information from the encoder output signals.

Abstract: In an X-Y addressable workpiece positioner the workpiece to be positioned, such as a semiconductive wafer to be aligned with a mask image, is coupled to move with a work stage moveable in the X-Y direction and having a two-dimensional array of positioning indicia affixed thereto for movement therewith. An enlarged image of a portion of the positioning array is projected onto a relatively stationary sensor stage to derive an output determinative of the X and Y coordinates of the positioning array relative to the position of the sensor. The sensed X and Y coordinates of the positioning array are compared with the X and Y coordinates of a reference positioning address to derive an error output. The work stage is moved in response to the error output for causing the workpiece to be positioned to the reference address.

Abstract: A servo control arrangement is provided that accurately controls the positioning of a movable member. The movable member is controlled by a motor through a drive train. A coded member is carried either by the drive train or the controlled movable member so as to move in accordance with the controlled movable member. The coded member includes an array of apertures with each of the apertures corresponding to a controlled position of the controlled movable member. In a preferred arrangement, the controlled movable member is a rotary turntable that carries a slide tray for projection apparatus. In that arrangement, each of the apertures corresponds to one of the slide positions of the rotary turntable and slide tray. Feedback information representing the position of the coded member is provided by alternately energized light sources and a single photodetector device.

Abstract: A scanning interferometer is provided with a substantially monochromatic reference beam having a wavelength outside the spectral region of principal interest. Modulation of the reference beam provides a measure of the scan velocity that is compared with a stablized time reference to provide an error signal used to regulate the scan velocity. Modulation of the reference beam also provides a fringe count. At a predetermined count, the time reference is changed in a pre-arranged manner, providing a pre-established scan acceleration sequence at the end of each scan. The acceleration sequence is selected to insure the direction of the scan is reversed within a quarter wave interval of the fringe count, insuring the fidelity of the fringe-count of the monochromatic reference source.