Abstract: A two-dimensional LD (laser diode) array light-emitting device constituted by stacking light-emitting units each having a LD bar and a cooling assembly for cooling the LD bar with a simplified electrical connection structure to reduce manufacturing cost. The cooling assembly is electrically connected with one electrode of the LD bar through the die spacer so that a part of the cooling assembly serves as one electrode of the light-emitting unit. The other electrode of the LD bar is electrically connected with a webbed extending section of a conductive layer of a TAB (tape-automated bonding) sheet so that the conductive layer serves as the other electrode of the light-emitting unit. A space between the adjacent cooling assemblies for arranging the LD bar is adjusted by the spacer sheet intervened between the TAB sheet and the cooling assembly.

Abstract: A cooling device suitable for cooling a laser diode bar constituting a surface illuminating device as a light source for exciting a laser medium of a solid-state laser oscillator of high power. The cooling device is capable of flowing coolant at sufficient flow rate by reducing the pressure loss in the flow passage of the coolant in the device, to realize a light source device of small thickness with high cooling capability and high reliability. The cooling device comprises a first plate member, one or more second plate member and a third plate member to be joined together to form a laminated body. The second plate member has grooved paths formed on both surfaces thereof and having depths greater than a half of thickness of the plate member, and also opened paths for communicating grooved paths formed on the first plate member and the third plate member.

Abstract: A motor drive method designed to eliminate the effect of variation of main voltage in the current control based on the PWM control. A main voltage detecting circuit detects a main voltage Vlink, and a main voltage equivalent value Vlink1 is set to be equal to this detected main voltage Vlink. Each of deviations between phase current commands Icu, Icv and Icw and phase currents iu, iv and iw detected is multiplied by the proportional gain K. Each product is then divided by the main voltage equivalent value Vlink1 to obtain respective phase duty ratios .eta.u, .eta.v and .eta.w of the PWM signal. The PWM signals with these duty ratios are outputted to an electric power converter to turn on or off the control switching elements for the drive control of the motor. The main voltage equivalent value Vlink1 is set to the detected main voltage Vlink to become equal to the actual main voltage, so that it becomes possible to calculate the duty ratio of the PWM signal which corresponds to the actual main voltage.

Abstract: A variable-reluctance motor is driven by means of a driver circuit which is composed of a common switching device and switching devices corresponding to individual phases. The sum (total current i.sub.t) of currents flowing through coils for the individual phases is detected. The duty ratio of a PWM signal for turning on and off the common switching device is computed in accordance with the deviation between the total current i.sub.t and a current command i.sub.cmd and the sign (positive or negative) of the deviation. Also, the on-off operation of the switching device corresponding to each phase is controlled depending on the excitation phase based on the rotor electrical angle and on whether the sign of the deviation is positive or negative. In this manner, current loop control is executed so that the detected total current i.sub.t follows up the current command i.sub.cmd.

Abstract: A driving apparatus for controlling the drive of a variable reluctance motor in a manner that an average voltage applied to an exciting coil linearly changes with respect to a current deviation or a current command. If the current deviation or the current command is positive or zero, a first transistor of a driving circuit is switched ON by a signal selector circuit in dependence upon a PWM signal from a PWM circuit. A polarity determination signal from a polarity determining circuit, and an output from an ON-OFF signal generating circuit. The PWM signal is generated in dependence upon an output of an absolute value circuit. A second transistor is turned ON and OFF in accordance with the PWM signal while the output of the circuit is at a high level, so that a positive line voltage and a zero voltage are alternately generated across a coil.

Abstract: An absolute position encoder outputs position data as absolute data. When a power supply is turned on, absolute position data is read from an absolute code pattern (6) and is set in a counter (14). Thereafter, the counter (14) effects counting of incremental pulses read from an incremental code pattern (7) and increments the contents of the counter (14). Accurate absolute data referenced upon startup to the absolute code pattern can thus be output even during a high speed rotation.

Abstract: A method is provided for detecting a position, comprising the steps of: producing two-phase sinusoidal wave signals having a 90.degree.-spatial phase difference therebetween upon movement of a moving object; detecting the current voltage V.sub.a and V.sub.b of the two-phase sinusoidal wave signals and calculating a value of .alpha. making a value of V zero, given by V=V.sub.a .multidot.cos.alpha.-V.sub.b .multidot.sin.alpha.; determining the value of .alpha. so that polarities of sin.alpha. and cos.alpha. for the calculated .alpha. coincide with those of V.sub.a and V.sub.b, respectively; and detecting a moving position of the moving object by using the value of .alpha. determined in the preceding step as absolute position data within 1 cycle of the 2-phase signals. According to the above method for detecting a position, the absolute position of a moving object can be detected with a high resolution.

Abstract: An optical rotary encoder is provided, which has a code disk formed with an analog code pattern (CP) so as to improve its detection resolution.The analog code pattern (CP) is continuously formed in the disk circumferentially of the disk, and has its radial width (W) set to a value which varies as a function of the rotational position of the disk, and continuously changes in the circumferential direction. A photoreceptor of the encoder generates a signal proportionate to an amount of light received through the pattern.

Abstract: A rotor rotational position detector for a motor is provided which is capable of detecting an absolute rotation position of a rotor shaft of the motor for one revolution of the rotor shaft. The detector also detects, simultaneously with the absolute detection, a rotor magnetic pole rotational position for motor driving control.The absolute rotational position of the rotor shaft in one revolution of the rotor shaft is detected and a coded signal (a), representative of the detected position, is output. The coded signal (a) is converted into a rotor magnetic position signal (b) for motor driving control by a code converting circuit (5), and is outputted therefrom.

Abstract: In an acceleration/deceleration control system of a servo motor, an acceleration/deceleration control section (5) has a low-pass filter (4) of second or higher order when an exponential acceleration/deceleration system is used, and the acceleration/deceleration section (5) has a linear acceleration/deceleration section (3) and the low-pass filter (4) of second or higher order connected to the output of the linear acceleration/deceleration section (3) when a linear acceleration/deceleration system is used. A position instruction (Pa) is filtered through the low-pass filter (4) of second or higher order, and a filtered signal is supplied to a servo control section (6), thereby driving the servo motor (M).

Abstract: A speed control apparatus according to the present invention includes a pulse generator for generating a number of pulses proportional to an angle of rotation of a servomotor, a speed signal generator for converting the frequency of the pulses into a voltage indicative of an actual speed of the servomotor in order to feed back the voltage through negative feedback, a detector for detecting reversal of the direction of rotation of the servomotor, a positional change detector for detecting the change in a position of the servomotor after the reversal of the direction of rotation of the servomotor by counting the pulses produced by the pulse generator, and a circuit for lowering the voltage indicative of an actual speed until the position of the servomotor has changed beyond a predetermined amount.

Abstract: Disclosed are a method and apparatus for providing speed information based on position pulses from a position detector for the purpose of controlling the speed of a motor. The invention includes a circuit for receiving the position pulses, and for counting the number N of pulses within a fixed period To. Measuring an interval T1 between a position pulse generated just prior to the fixed period To and the instant at which the period To begins and for measuring an interval T2 between the final position pulse generated in the period To and the instant at which the period To ends. The operation T=To+T1-T2 is performed to obtain the time T required for input of the position pulses, the time T is divided by the number N of pulses, and speed information V is obtained by performing the operation V=K.multidot.N/T, where K is a proportional constant.