摘要:
An apparatus having a first system for forming a composite light beam of two light beams to be made to interfere with each other, a splitting member for amplitude-splitting the composite light beam into three or more split light beams in the same area, and a second system for obtaining interference light beams of different phases from the plurality of split light beams. Also, an apparatus for effecting information recording on a hard disc drive device comprising an (i) optical system for splitting a light beam into two light beams, causing one of the two light beams to be condensed and reflected by the side of an arm for a recording reading head in the hard disc drive device, and superposing the condensed and reflected light beam on the other light beam to thereby obtain a composite light beam, (ii) a splitting member for amplitude-splitting the composite light beam into three or more split light beams in the same area, (iii) an optical member for obtaining interference light beams of different phases from the plurality of split light beams, (iv) light receiving elements for detecting respective ones of the interference light beams of different phases, (v) a control system for effecting the positioning of the arm on the basis of the result of the detection by each of the light receiving elements, and (vi) a signal writing-in system for writing a signal into a hard disc through the recording reading head each time the arm is positioned.
摘要:
An apparatus for detecting the displacement information of an object has a light source, a diffraction grating for diffracting a light beam from the light source so that the light beam diffracted by the diffraction grating is incident on the object, and a photodetector for detecting the light from the object caused upon the incidence of the light beam thereon by the diffraction grating. Information regarding the relative displacement to the object along a predetermined direction is detected on the basis of a light detection signal from the photodetector. The diffraction grating is formed so that the light beam applied to the object may be condensed on the object in a direction in which the relative displacement to the object cannot be detected by the signal from the photodetector.
摘要:
An apparatus for detecting position change information of an object includes a contact member for contacting the object, and a detecting unit for obtaining position change information of the object by detecting a change in force applied from the object to the contact member.
摘要:
Disclosed is a frequency shifter for shifting a frequency of incident light beams. The frequency shifter has an electro-optic element for making incident the light beam whose frequency is to be shifted, an electrode unit disposed on the electro-optic element, an electric charge imparting circuit for imparting an electric charge to the electrode unit and a discharging circuit for discharging the electric charges accumulated in the electrode unit. Disclosed also is an apparatus, having the frequency shifter, for optically measuring relative displacement data to a measured object.
摘要:
A Doppler velocimeter determines a state of noise generation in a detection signal including a Doppler signal component based on comparison by a preceding/succeeding-signal comparator for comparing the detection signals before and after passing through a band-pass filter for cutting noise adjusted to the frequency of the detection signal, and/or includes a filter circuit for determining passage/interruption of the detection signal after passing through the band-pass filter from a relationship between the count value of a first counter, in which the output of a first frequency multiplier for multiplying the frequency of the detection signal by N is made to be a clock signal and a leading edge in the detection signal is made to be a reset trigger, and a leading edge in the detection signal, and/or includes an error signal generator for generating an error detection signal by detecting a periodic error in the detection signal after passing through the band-pass filter from a relationship between the count value of a second counter, in which the output of a second frequency multiplier for multiplying the frequency of the detection signal by N and a leading edge in the detection signal is made to be a reset trigger, and a leading edge in the detection signal after passing through the band-pass filter, and/or includes a phase comparator for generating a control signal by comparing the phase of the detection signal with the phase of a comparison signal to be compared, an oscillator for controlling the frequency of its output signal in accordance with the control signal from the phase comparator, and a comparison-signal generation unit for generating a comparison signal based on the output of the oscillator. When an error has been detected, a switching unit interrupts the control signal and the phase comparator is reset and stops comparison, and when the error has ended, the switching unit communicates the control signal, the phase comparator starts comparison, and the comparison-signal generation unit generates a comparison signal whose phase coincides with the phase of the detection signal.
摘要:
A position information detection apparatus includes a first detection system for radiating two collimated light beams onto an object to be measured at a predetermined crossing angle to form interference fringes at a predetermined interval, and detecting scattered light emanating from the object to be measured by the interference fringes at the predetermined interval, a second detection system for radiating two light beams onto the object to be measured at a predetermined crossing angle to form interference fringes having a gradient with each other in an opposing direction to the object to be measured, and detecting scattered light emanating from the object to be measured by the interference fringes having the gradient, and a detection unit for comparing output signals from the first and second detection systems, and detecting relative position information, along the opposing direction of the first and second detection systems, of the object to be measured.
摘要:
A frequency shifter is capable of controlling the adverse influences of electric noise caused by the voltage applied to electrooptical elements of a frequency shifter. The frequency shifter modulates the phase of the luminous flux entering the electrooptical elements by applying a voltage to the electrooptical elements; the shifter is provided with a shield for electrically shielding the circuit for generating the voltage to be applied to the electrooptical elements and the electrooptical elements from an external circuit.
摘要:
This invention has as its object to provide a frequency tracking method, a frequency control apparatus (tracking apparatus) using this method, and a Doppler velocity meter using the same, which easily and quickly allow the center frequency of a band pass filter to coincide with the frequency of an input signal even when an input signal suffers from a large level drift. A tracking method for a center frequency of a band-pass filter relates to a method including the deviation information detection step of detecting deviation information of the frequency of a signal to be input to the band-pass filter or a signal output from the band-pass filter with respect to the center frequency of the band-pass filter, the deviation information detection step including at least the step of detecting the deviation direction, and the changing step of changing the center frequency of the band-pass filter on the basis of a detection result in the detection step of detecting the deviation information including the deviation direction, thereby adjusting the center frequency of the band-pass filter to coincide with the frequency of a signal to be filtered through the band-pass filter.
摘要:
A Doppler velocimeter includes an illuminating system for projecting a light beam for measurement onto an object to be measured at a predetermined working distance, and a light-receiving system for receiving light from the object illuminated with the light beam by the illuminating system. Information relating to a speed of the object is detected by a Doppler shift of the light received by the light-receiving system. The Doppler velocimeter further includes a changing device for changing the working distance of the illuminating system.
摘要:
This invention relates to a sheet feeding device having an endless belt for feeding a sheet; multiple rotation members bodies supporting the endless belt and including at least one crown roller, a cylindrical rotational member located between the crown roller and a first body member among the multiple rotation members from the crown roller in the endless belt moving direction.