SU1068697A1 - Device for measuring gap between magnetic head and disk medium - Google Patents

Abstract

A DEVICE FOR MEASURING A CLEARANCE BETWEEN A MAGNETIC HEAD AND A DISK MEDIUM, containing reflected from the surface of the magnetic head, a wave sensor connected to a monochromator, ana-. a logo-digital converter, a calculator connected to the output of the wave number sensors and to the output of an analog-digital converter, and a recorder connected to the output of the calculator "1, while the transparent disk carrier is placed between the translucent mirror and the magnetic head, characterized in that , in order to improve the accuracy of measuring the instantaneous values of the gap between the magnetic head and the surface of the disk carrier, it is equipped with an analog memory block, a position sensor of the disk carrier and a control unit a delayed delay connected to the output of a disk carrier position sensor, while the analog storage unit is connected between the photodetector output and the analog-to-digital converter input, and the control input of the analog storage unit and control of the caller are connected to the output block adjustable delay. . o: 00 and d with d

Description

The invention relates to a measurement technique, namely, devices for measuring the gap between the surface of a magnetic head and the surface of a disk carrier. A device for measuring the gap between the working angle of a magnetic head and a magnetic recording medium is known, which comprises a light source, a polarizer, a magneto-optical element, a modulator and a ClD photodetector. The closest in technical essence and the achieved effect to the proposed is a device containing. Consistently on the optical axis a light source, a first lens, a monochromator, a second lens, a translucent mirror mounted at an angle to the optical axis, and a photoreceiver mounted with the possibility of receiving wave beam reflected from the surface of the magnetic head, a wave number sensor connected to a monochromator, an analog-to-digital converter, a computer connected to the output of the wave sensor In addition, there are new numbers both to the output of the analog-digital converter and the recorder connected to the output of the calculator, while the transparent disk carrier is placed between the translucent mirror and the magnetic head G2. A disadvantage of the known devices is that the averaging of measurement results, due to the structural features of the device, does not allow an analysis of the instantaneous values of the measured value with high accuracy. The purpose of the invention is to improve the measurement accuracy of the instantaneous values of the gap between the magnetic head and the surface of the disk carrier. . The goal is achieved in that a device containing a light source arranged in series on the optical axis, a first lens, a monochromator, a second lens, a translucent mirror mounted at an angle to the optical axis, and a photodetector mounted to receive a light beam reflected from the surface of the magnetic head , a wave number sensor connected to a monochromator, an analog-to-digital converter, a transmitter connected to the output of a wave number sensor and to the output of an analog-to-digital converter, and a register Torr connected to the output, the calculator, the transparent disk medium disposed between the semitransparent mirror and the magnetic head -snab. An analogue storage unit with a disk carrier position sensor and an adjustable delay unit connected to a disk carrier position sensor output, with an analog storage unit connected between the photodetector output and the analog-digital converter input, and the analog input control input and analog control input -digital converter connected to the output of the adjustable delay unit. FIG. 1 is a block diagram of a device for measuring the gap between a magnetic head and a disk carrier; in fig. 2 - timing diagrams for the operation of the device. The device contains optically coupled light source 1, lenses 2-4, monochromator 5, a translucent mirror 6 placed at an angle to the optical axis, a transparent disk carrier 7, a magnetic head 8, and a photodetector 9, to the output of which through an antshig zap (padding unit 10 Analog-to-digital converter 11 is connected. The device also contains a calculator 12, a recorder 13 connected to the output of the calculator 12, a sensor 14 of the wave numbers included between the output of a monochromator 5 and the input of the calculator 12, a sensor 15 of the position of the disk carrier 7 and Adjustable delay block 16. The photodetector 9 is arranged to receive a light beam reflected from the surface of the magnetic head 8. A transparent disk carrier 7 is placed between the magnetic head 8 and the translucent mirror 6. The sensor 15 of the position of the disk carrier 7 is connected to the control the input of the analog storage unit 10 and with the control input of the analog-digital converter 11, the output of which is connected to the input of the calculator 12. The device operates as follows. The monochromator 5 separates from the light of source 1 a narrow spectrum of waves, which through lens 3 is directed to a semi-transparent mirror 6. The beam reflected from the semi-transparent mirror 6 through the transparent disk carrier 7 hits the surface of the magnetic head 8, reflects from the latter and through the semi-transparent mirror 6 and the lens 4 hits the photodetector 9, the output of which produces a signal proportional to the luminous flux. The sensor 15 produces pulses with a follow-up period equal to the period of rotation of the disk when the disk carrier 7 rotates. kovogo carrier 7, wherein the pulse decline associated with: phase position of the disc medium 7 (Fig 2a.). The pulse of the sensor 15 for the position of the disk carrier 7 is delayed in the delay block 16 (Fig. 26) and is fed to the control of the inputs of the analog memory of the block 10 and the analog-digital converter 11. The pulse decay of the block 10 is switched to the storage mode of the previous information, and the converter 11 converts an analog signal into a digital code; the analog signal at the output is analog. the storage unit 10 has a value in accordance with the luminous flux falling on the photodetector 9 and caused by interference phenomena of the fluxes reflected from the surface of the magnetic head 8 and the working surface of the magnetic disk carrier 7. The code corresponding to the luminous flux and the code corresponding to the wavelength of the monochromator 5, served from B

a converter 11 and a wave number sensor 14 to the inputs of the calculator 12, in which the magnitude of the gap between the surface of the magnetic head 8 and the surface is calculated

o magnetic disk carrier 7. A change in the delay time of the pulse sensor 15 of the position of the disk carrier 7 is provided by sampling an instantaneous gap value.

5 The invention makes it possible to increase the accuracy of measuring the instantaneous values of the gap by binding the measurement e. my values to the phase coordinate of the disk medium.

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Claims (1)

A DEVICE FOR MEASURING THE GAP BETWEEN A MAGNETIC HEAD AND A DISK CARRIER, containing a light source arranged in series on the optical axis, a first lens, a monochromator, a second lens, a translucent mirror mounted at an angle to the optical axis, and a frt detector installed with the possibility of receiving a light beam reflected from the surface of the magnetic head, a wave · number sensor connected to a monochromator, analog-to-digital converter, comp. litel connected to the output of the wave * sensor and to the output of the analog-to-digital converter, and a recorder connected to the output of the calculator, while a transparent disk medium is placed between the translucent mirror and the magnetic head, characterized in that, in order to increase the measurement accuracy instantaneous values of the gap between the magnetic head and the surface of the disk medium, it is equipped with an analog storage unit, a position sensor of the disk medium and an adjustable delay unit connected to the output of the sensor The position of the disk medium, with the analog storage unit connected between the output of the photodetector and the IL input of the analog-to-digital converter, and the control input of the analog storage unit and the control input of the analog-to-digital converter g connected to the output of the adjustable delay unit. 'fig!