JPH0467124B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a spacing measurement method used for measuring the spacing of a magnetic head used in a magnetic disk storage device, a magnetic tape storage device, a mass storage device (MSS), etc. Regarding.

The magnetic head floats on the surface of a magnetic recording medium moving at high speed by maintaining a minute gap (referred to as spacing) on the order of submicrons by the action of hydrodynamic force. It is important to keep this spacing small and stable in order to improve the performance of the magnetic head. Therefore, it is also important to accurately measure this spacing.

Conventionally, this spacing is achieved by replacing one of the magnetic recording medium and the floating slider of the magnetic head with a transparent body (mainly, the medium is replaced with a transparent body, for example, a glass substrate is used), the floating slider is made to float,
The most accurate measurement method is used, which utilizes interference fringes generated between a floating slider and a magnetic recording medium when light is incident through a transparent body. For example, the spacing can be determined by injecting white light and determining the color of the reflected interference light with the naked eye (IBMJ. A method of determining the spacing from the position of the interference fringes that occurs is known. Recently, the spacing between a magnetic head and a recording medium has been gradually reduced due to improvements in recording density. Along with this, there is a desire for higher accuracy and shorter measurement time in spacing measurements.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for measuring magnetic head spacing that can be easily and quickly measured, and can significantly shorten the measurement time compared to the conventional method.

[Summary of the invention]

According to the first embodiment of the present invention, the planar position of the magnetic head is detected using a two-dimensional photoelectric conversion device that detects a planar image of the magnetic head, and a pattern position detection device that detects the position of the magnetic head, Further, by determining the spacing measurement position from the relationship between the spacing measurement position input in advance and the planar image of the magnetic head, the measurement time can be shortened.

Furthermore, according to the second embodiment, a plurality of transparent bodies are placed at positions corresponding to a plurality of magnetic recording media, and illumination light can be introduced into the spacing between all the magnetic heads and the transparent bodies. Furthermore, by providing a detection optical system that can observe the interference of light occurring in each part, all the magnetic heads fixed to one magnetic head assembly can be detected at one time. Measurement can be done in a fixed manner, reducing spacing measurement time.

Furthermore, according to the third embodiment, white light is incident on the spacing section, the reflected interference light is imaged by the lens system, and an arbitrary point on the floating slider is formed using a pinhole provided on the imaging surface. Separate the light from a point, decompose it into monochromatic light using a spectrometer, calculate the reflectance of each monochromatic light, and determine the wavelength dependence of the reflectance to measure the interference wavelength. From this, we can calculate the spacing. get. As a result, spacing can be easily and quickly measured without calibration using another method, and measurement time can be significantly shortened.

[Embodiments of the invention]

The present invention will be explained below using examples. first,
A first embodiment of the present invention will be described with reference to FIG.
In the figure, a magnetic head 1 is held by a magnetic head holding arm 10 and floats above a transparent glass disk 2 which is rotated via a pulley 5, spindle 4 and hub 3 from a motor (not shown). The magnetic head holding arm 10 is moved in the radial direction on a rail 21 by a lead screw 22 rotated by a pulse motor 23. The magnetic head 1 can also be floated above the glass disk (load) or held (unloaded) sufficiently separate from the glass disk by an unload bar 11 that is driven up and down by a load/unload device 12. I'm starting to be able to do that.

The light beam from the xenon lamp 100 enters the monochromator 110 and is emitted as zero-order white light or first-order diffracted monochromatic light depending on the rotation angle of the diffraction grating. The light beam from the monochromator 110 is divided into two by a half mirror 122, one of which passes through the glass disk 2 and enters the floating spacing between the magnetic head 1 and the other which is incident on a photodiode 140 for detecting the amount of incident light. incident on .

The light beam incident on the floating spacing section is reflected by interference at the floating spacing section, and is reflected by the half mirror 122.
through the lens 130 and the television camera 12
A floating spacing image is formed on the zero imaging plane.

Xenon lamp 100 and monochromator 11
0 is held on a light source mount 101 and fixed on a base 6. TV camera 120, lens 1
30, cover 131, half mirror 122, and photodiode 140 are held on camera stand 121 and movably held on base 6.

The photodiode 140 is a monochromator 1
A photocurrent is output based on the output light amount from 10. The preamplifier 141 amplifies the photocurrent from the photodiode 141 and outputs a voltage proportional to the photocurrent. A/D converter 142 converts the output voltage of preamplifier 141 into a digital value.

The television camera 120 has a camera control circuit 150
It outputs a voltage proportional to the intensity of light at the floating spacing portion of the imaging surface, and is stored as a digital value in the frame memory 160. Also,
At the same time, a TV camera 1 is placed on the monitor TV 151.
The output of 20 displays an image of the floating spacing.

The pattern position detection device 170 detects the position of the magnetic head based on the image information stored in the frame memory 160. This operation will be explained below. The magnetic head is in view as shown in FIG. In the reflected image with white light, the reflected light is strong only on the two magnetic head floating surfaces 15 and weak on the other parts, so when the image is binarized with an appropriate threshold, it becomes 2
The inside of one magnetic head floating surface 15 can be converted to "1", and the other parts can be converted to "0". Here, as shown in Fig. 3, two magnetic head floating surfaces 1
Although the description will be made assuming that 5 is a rectangle, it goes without saying that other shapes can also be similarly detected by applying the detection method described below.

An example of determining the center position (x, y) of the magnetic head floating surface 15 will be described below with reference to FIG. Here, a method for detecting the upper floating surface of the two upper and lower surfaces will be described, but it is clear that the lower floating surface can also be detected in the same manner. Let the standard position of the magnetic head floating surface be (x ₀ , y ₀ ). In addition, 0 in the figure
is the origin. First, the deviation expressed as e=x- _x0 ...(1) f=y- _y0 ...(2) is determined. Let the upper limits of the absolute values of the deviations e and f be E and F, respectively. Rectangular areas 163 and 164 each having a width of 2F in the vertical direction and d in the left and right directions are set centering on the intersection of standard positions 161 and 162 on the upper and lower sides of the floating surface and _x0 . The values of pixels inside rectangular areas 163 and 164 are sequentially read out from the binarized image, and the areas S ₁ and S ₂ are calculated from the number of pixels that are "1", respectively. Here, S ₁ and S ₂ are expressed by the following formula.

S ₁ = (F - f) d ... (3) S ₂ = (F + f) d ... (4) Therefore, from equations (3) and (4), the deviation f is f = 1/2d (S ₂ -S ₁ )...(5) Therefore, from this f, the position y can be found as y=y ₀ +f...(6).

Next, the standard positions 165, 166 for the left side and right side of the floating surface
Rectangular areas 167 and 168 each having a width of d in the vertical direction and 2E in the horizontal direction are set with the intersection of and y as the center. The values of pixels inside rectangular areas 167 and 168 are sequentially read out from the binarized image, and the areas S ₃ and S ₄ are calculated from the number of pixels that are "1", respectively.
S ₃ and S ₄ are expressed by the following formula.

S ₃ = (E-e) d ... (7) S ₄ = (E + e) d ... (8) Therefore, the deviation e and position x are e = 1/2d (S ₄ - S ₃ ) ... (9) x=x ₀ +e ...(10) It can be found.

The dimensions of the rectangular image (floating surface) 15 vary due to manufacturing errors of the magnetic head, and can be determined as follows, where the width error is δ _Y and the length error is δ _X.

δ _Y =2F− _{S 1} + _{S 2 /} d ……(11) _δ Coordinates of points 16, 17 in l ₁ , l ₂ (X ₁ , Y ₁ ),
(X ₂ , Y ₂ ) is obtained as follows.

X ₁ = X + L + δ _X /2 _{- l 1} ... (14) _{X 2 = X} + L + δ .

The case where the slider axis is parallel to the Y axis has been described above, but if there is an inclination, two more rectangular areas are provided at different positions in the X direction from the rectangular areas 163 and 164. It is clear that the above operation can be extended by detecting the inclination with respect to the axis.

The control device 180 controls the overall operation as follows.

Spacing measurement proceeds in the following order.

The glass disk 2 is rotated at a predetermined number of rotations.

The magnetic head moving table 20 is moved to the farthest side from the spindle 4, and the magnetic head 4 attached to the magnetic head holding arm is fixed to the moving table 20.

The load/unload device 12 is operated and the unload bar 11 brings the magnetic head 1 into an unloaded state.

After rotating the pulse motor 23 and advancing the magnetic head moving table 20 to position the magnetic head 1 at the loading position on the outer periphery of the glass disk 2, the loading/unloading device 12 is operated to move the magnetic head 1 onto the glass disk. Float to 2.

Furthermore, the magnetic head moving table 20 is advanced to position the magnetic head 1 at the spacing measurement position.

The diffraction grating of the monochromator 110 is rotated to allow zero-order white light to enter the floating spacing.

Because white light includes light from short wavelengths to long wavelengths, the light reflected from the floating spacing does not show clear interference fringes as it does with monochromatic light, and the light reflected from the entire surface of the floating spacing does not appear on the TV. An image is formed on the camera 120. Frame memory 1
60 to be stored.

The data in the frame memory 160 is read out to the pattern position detection device 170 to determine the X and Y coordinates of the spacing measurement point. This value is stored in the controller.

Monochromator output light wavelength from 220mm to 740mm
The output image from the television camera 120 at each wavelength is stored in the frame memory 160, and the reflected light output at each point of the X and Y coordinates determined in is stored in the control device 180. do.

At the same time, the light intensity of the light source at each wavelength is detected by the photodiode 140, and the preamplifier 141 detects the light intensity of the light source at each wavelength.
A value proportional to the light intensity is obtained by the A/D converter 142 and stored in a separate memory section in the controller.

The reflectance of the spacing portion is determined from the ratio of the reflected light intensity obtained above and the light source light intensity, and the interference fringe order and interference wavelength are determined. The method for determining the interference fringe order and interference wavelength is described in detail in Japanese Patent Application No. 115060/1982.

The control device 180 provides the printer 190 with X, Y
Print out position and spacing measurements.

The magnetic head moving table 20 is moved backward, the magnetic head 1 is positioned at the loading position, the load/unload device 12 is operated, and the magnetic head 1 is retracted from the surface of the glass disk 2.

The magnetic head moving table 20 is further retreated and fixed at the same position as above, the load/unload device 12 is released, and the magnetic head 1 is removed.

According to the device used in this example, the conventional
It is now possible to determine the X and Y coordinates of a measurement point that used to take 30 seconds in less than 1 second.

This is an extremely significant effect because in actual magnetic head assemblies, it is necessary to measure four magnetic heads at the same time, and when measuring four points per header, the measurement time is about 10 minutes, which is about 1 minute. 1/10, allowing efficient automatic 100% measurement.

Note that the spacing measurement method itself is not limited to the method of scanning wavelengths as described here, and may be determined based on the interference fringe position on the floating slider or the color of the spacing measurement point.

FIG. 4 is a plan view of an apparatus used in a second embodiment of the present invention.

The transparent glass disks 2A and 2B have a hub 227,
It is fixed to the rotating shaft 200 by a spacer 228 and a clamp ring 229. The rotating shaft 200 is supported horizontally by bearings 225 and 226, and is rotatably fixed on the measuring device base 220.

A pulley 224 is further fixed to the rotating shaft 200, and is driven by a belt 231 from a motor 230 to rotate at a predetermined number of rotations.

The magnetic head assembly 210 is fixed to a carriage 215, and the transparent disks 2A, 2 are mounted on a rail 216.
Move in the radial direction of B. Magnetic head assembly 21
The magnetic heads 211 and 212 on the transparent disk 2B float on the transparent disk 2B, and the magnetic heads 213 and 214 on the transparent disk 2A float on the transparent disk 2A.

Xenon lamp 10 installed on base 220
The light from 0 becomes monochromatic light by the monochromator 110, becomes parallel light by the lens 270, and is divided by the half mirror 257 into light going to the transparent disk 2A and light going to the transparent disk 2B.

The light going to the transparent disk 2A is reflected by the mirror 261, and is divided by the half mirror 256 into the light going to the magnetic head 213 and the light going to the magnetic head 214.

The light going to the magnetic head 213 is reflected by the mirror 263, then by the half mirror 253, and passes through the transparent glass disk 2A to illuminate the spacing between it and the magnetic head 213. Magnetic head 213 and transparent glass disk 2A
The light illuminated on the spacing section between the two is reflected by interference, passes through the half mirror 253, enters the lens of the projector 203, and is projected and imaged as an interference pattern of the spacing section on the projection plane. .

The light going to the magnetic head 214 passes through the half mirror 2
54 illuminates the spacing of the magnetic head 214, where it is reflected by interference, passes through the half mirror 254, and is imaged by the projector 204 onto a projection plane.

After the light going to the transparent glass disk 2B is reflected by the half mirror 257, the light goes to the half mirror 25.
5 into the light going to magnetic heads 211 and 212.

The light going to the magnetic head 211 is reflected by the mirror 262 and then by the half mirror 251 to illuminate the spacing portion of the magnetic head 211. The interference reflected light there is reflected by the half mirror 25.
1 and is imaged on a projection plane by a projector 201.

The light going to the magnetic head 212 is passed through a half mirror 25.
2 and illuminates the spacing of the magnetic head 212. The interference-reflected light passes through the half mirror 252 and is imaged on a projection surface by the projector 202.

From the images of the spacing portion formed on these projection planes, the spacing of the magnetic head is determined by a known method described in the above-mentioned literature, for example.

In this way, the light from the xenon lamp 100 simultaneously hits the four magnetic heads 211, 212, 213, 2.
Since the magnetic head is incident on 14 spacing sections, the number of radial movements of the magnetic head is reduced from 6 to 6 as shown in Fig. 5A and B, compared to the conventional measurement of only one head on one side. The number of times for installation and removal is also halved from two to one. Therefore, the probability of damaging or deforming the magnetic head or the magnetic head support during attachment and detachment is reduced by half, and the spacing measurement time is also significantly shortened. In addition, Figure 5A shows the conventional spacing measurement procedure in Figure 5B.
shows the measurement procedure of the apparatus used in this example.

In addition, since the rotation axis is horizontal and the bearings for the light source, projector, optical system, and transparent glass disk are installed on the same base, fluctuations in the distance between the light source, projector, optical system, and the transparent glass disk are minimized. This makes it possible to perform highly accurate measurements.

Furthermore, since there is no need for an intermediate frame for separately installing the light source, projector, and optical system on the base as in the prior art, the entire measuring device can be configured to be small and lightweight. Therefore, according to the apparatus used in this embodiment, the spacing of the magnetic head can be measured in a short time with a small and lightweight configuration.

In addition to the apparatus used in this embodiment, the measurement position automatic determination device described in the first embodiment and the earlier patent application
By adding the automatic measurement function of No. 56-115060, it becomes possible to measure four magnetic heads simultaneously and automatically, further shortening the measurement time.

Next, a device used for spacing measurement that can further shorten measurement time will be described. FIG. 6 is a diagram showing an apparatus used in the third embodiment of the present invention, in which white light is used as the measuring light, and the interference light reflected from the spacing part is separated into monochromatic light by a spectrometer. The spacing is obtained by measuring the interference wavelength from the reflectance of these monochromatic lights. In the apparatus used in this example, a concave diffraction grating was used as a spectroscopic device, and a silicon licenser was used as a monochromatic light detection device.

A magnetic head 1 is suspended above a transparent glass disk 2 which is rotated by a belt 5. White light from the xenon lamp 300 is incident on the spacing between the magnetic head 1 and the glass disk by the half mirror 322.

The light interfered and reflected by the spacing portion enters the lens 320 and forms an image on the pinhole plate 330.

The light passing through the pinhole 331 on the pinhole plate 330 enters the concave diffraction grating 340.

In this embodiment, the diffraction grating 340 has a radius of curvature of 50 mm.
300 grating grooves per mm are formed on the concave spherical surface of the spherical surface, and the diffracted and reflected light has its optical path bent by a mirror 341 and enters a line sensor 350.

Line sensor 350 has 64 sensors with a 110 μm opening.
They are arranged at a pitch of 127 μm and a length of 8.1 mm. On this 8.1mm long line sensor 350
Light in the range of 540 nm between 230 nm and 770 nm is incident. Therefore, 540/64nm per sensor
Light in the wavelength range is incident. For example, the center wavelength λ _N of light incident on the Nth sensor from the short wavelength side
is calculated using the following formula.

λ _N = 230 + 540/64 (N-1/2) ... (17) (N = 1, 2, 3, ... 64) The line sensor 350 controls each sensor by the drive signal from the line sensor control circuit 400. A charge proportional to the amount of incident light is output, and a voltage proportional to the amount of incident light is sequentially outputted to the output of the control circuit 400 for each wavelength.

The output of the line sensor control circuit 400 is sent to a sample and hold circuit 410, and the sample and hold circuit 410 outputs the output of the line sensor control circuit 400.
The output voltage is held for the time required for the A/D conversion circuit 430 to convert the short pulse from the output voltage.

A/D conversion circuit 430 converts the output voltage of sample hold circuit 410 into an 8-bit digital value and sends it to memory circuit 440.

The timing control circuit 420 is the arithmetic control circuit 4
Under the command of 50, the line sensor control circuit 40
0, sends a timing signal to the sample hold circuit 410, A/D conversion circuit 430, and memory circuit 440, and provides a trigger for sending out the light intensity signal output from the line sensor 350 at every sample time T of ₁ second. A light intensity signal is sent out at intervals of _T2 seconds, sampled and held in synchronization with this signal, A/D converted, and sent to the memory circuit 440.
Each wavelength is stored in a storage area at a different address.

Arithmetic control circuit 450 controls the overall operation, performs arithmetic operations to obtain spacing values from digital values stored in memory circuit 440, and outputs the results to printer 190.

Spacing measurements are performed as follows.

The output from each sensor No. is measured in a state where no light is incident on the line sensor 350, and the offset voltage E _ON is stored in the memory circuit 440.

The distance between the disk 2 and the head 1 in the spacing section is set to 0.1 mm or more, and light that does not cause interference is made incident on the line sensor 350, and E _BN is measured as a voltage proportional to the reference light amount of each wavelength. It is A/D converted and stored at an address different from E _ON in the memory circuit 440.

The magnetic head 1 is floated above the glass disk 2, and the output E _MN from each sensor is detected every T ₁ seconds.
The data are A/D converted and sequentially stored in locations different from E _O and E _B in the memory circuit 440.

The arithmetic control circuit 450 calculates the offset voltage.
Subtract from E _B and _EM , and find the interference reflectance R _N at each wavelength using the following formula.

R _N =E _MN −E _ON /E _BN −E _ON ...(18) (N=1, 2, 3, ...63, 64) Using the minimum value of the reflectance R _N , 56
The spacing is determined using the method disclosed in Japanese Patent Application No. 115060, and the resulting value is output to the printer 190.

In this example, T ₁ = 1 ms, T ₂ = 10 μs,
We were able to perform measurements at a sample rate of 1KHz.

FIG. 7 shows an apparatus used in a fourth embodiment of the present invention, in which a photodiode array is used as a detection device for separated light. pinhole plate 30
Since the earlier optical path is the same as in the first embodiment, it is omitted here.

The light passing through the pinhole 331 of the pinhole plate 330 is separated into spectra by the diffraction grating 340'.
It is reflected by the mirror 341 and enters the photodiode array 500.

The diffraction grating 340' has a radius of curvature of 100 mm and the number of grooves.
A concave diffraction grating of 300 lines/mm separates and images light with a wavelength of 400 to 600 nm onto a 3 mm length range of the photodiode array 500.

The photodiode array 500 has 30 photodiodes arranged at a pitch of 0.1 mm, into which light with a wavelength of 400 nm to 600 nm separated by the diffraction grating 340' is incident. Therefore, the center wavelength λ _N of the light incident on the Nth photodiode from the short wavelength side is
is obtained from the following equation.

λ _N =400+200/30×(N-1/2) (19) The output from each photodiode is input to the corresponding preamplifier in the photocurrent amplifier circuit 510. The amplification degree of each preamplifier can be adjusted independently, and the glass disk 2 and magnetic head 1
The output of all preamplifiers is set to the specified value when the distance between (for example, 0.5V), and
Corrects wavelength-related differences in photodetection output from the optical system and photodiode.

The output of each preamplifier of photocurrent amplification circuit 510 is input to comparator circuit 520 and each corresponding comparator. Each comparator compares the output of each preamplifier with a comparison voltage from the comparison voltage generator 550, and when the comparison voltage becomes high, the output goes high.

The output of each comparator in comparator circuit 520 connects each corresponding latch in latch circuit 530 to
It is input to OR gate 560.

Each latch in latch circuit 530 is set when the output of the corresponding comparator goes high and is reset by a reset signal from control circuit 570.

Latch circuit 530 has the output of each latch connected to the input of each corresponding bit of register 540, and sets the corresponding bit of register 540 when a set signal is received from control circuit 570.

The output of each comparator of the comparator circuit 520 is also input to the OR gate 560, and when any one of the outputs of these comparators becomes a high level, the output is set to a high level, and the comparison voltage is applied to the preamplifier of the photocurrent amplification circuit 510. The control circuit 570 is informed that the value is larger than either one.

Comparison voltage generator 550 is a comparator circuit 52
A comparison voltage to be sent to zero is generated by a command from the control circuit 570. The comparison voltage is initially 0V and 500nsec.
The voltage is increased by 5 mV each time. Therefore, when the output of the OR gate 560 first becomes a high level, the photodiodes in the photodiode array 500 of the comparators of the comparator circuit 520 receive the wavelength corresponding to the interference wavelength in the spacing section. The output of the comparator corresponding to the one with the minimum output is at a high level, and the number of the latches set in the latch circuit 530 corresponds to the interference wavelength of the spacing section.

FIG. 8 shows each preamplifier output voltage when the floating spacing between the magnetic head 1 and the glass disk 2 is 0.25 μm. Light with a wavelength of 503 nm is incident. The 15th preamplifier output is the minimum at 0.198V. Therefore, the comparison voltage should be set from 0.195V.
When the voltage is increased to 0.200V, the 15th comparator output goes high, the 15th latch is set, the output of the OR gate 560 goes high, and the control circuit 570 causes the comparison voltage generation circuit 550 to change the comparison voltage. At the same time, the set signal rewrites the contents of the register 540, setting the 15th bit to "1" and setting the other bits to "0".

D/A conversion circuit 580 generates an analog signal output proportional to the number of bits that are "1" in register 540, and can be used for real-time spacing dynamics measurements.

Further, the digital display circuit 590 is connected to the register 54
The bit number set to "1" in 0 is displayed and can be used to read the absolute value of the interference wavelength.

In this case, the interference wavelength of 503 nm is the first order interference wavelength, and the floating spacing is half that.
It is determined to be 0.252μm.

The control circuit 570 controls the overall operation as described above, and when measuring dynamic characteristics, it resets the latch circuit 530 so that measurement can be started again, resets the output voltage of the comparison voltage generator 550 to zero, and then resets the voltage again. command to rise.

In the apparatus used in this example, the time required for one measurement is 0.5 μsec for one step, so
It takes 40 steps and 20μsec to increase mV to 0.200V. The minimum output voltage at the interference wavelength is about 20 to 50% (0.1 to 0.25 V) of the standard output adjustment, and the measurement time does not exceed 30 μsec at the maximum.

Therefore, a sampling rate of about 30KHz can be achieved.

In this example, 32 photodiodes have 400
~600nm light detected, spacing 0.2~
The purpose was to detect the primary interference wavelength of 0.3 μm, but
The interference order and wavelength range are not limited to these.
Measurement is possible if the interference order is known in advance and the spacing is 0.1 μm or more.

Furthermore, in the apparatus used in the embodiments of FIGS. 6 and 7, the spectral detection section after the pinhole plate 330 is movable as a unit in two orthogonal directions in a plane perpendicular to the optical axis. It is possible to measure the floating spacing at any point on the magnetic head 1.

Further, in the apparatus used in the embodiment shown in FIG. 6, a line sensor is used as the detection element, but the detection element is not limited to this, and any one-dimensional optical sensor may be used, such as a CCD sensor, a vidicon camera,
Any photodetecting element capable of position scanning, such as an image desector, may be used.

〔Effect of the invention〕

As described above, according to the present invention, the spacing measurement position can be automatically determined, and all the magnetic heads fixed to one head assembly can be measured by fixing the head assembly once. It can significantly shorten the time and is effective in speeding up spacing measurements. In addition, dynamic measurements can be performed at frequencies from several 100 Hz to several 10 KHz, and a highly accurate and high-speed spacing measurement method can be realized.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a device used in the first embodiment of the present invention, FIG. 2 is a diagram showing a screen on a monitor television, FIG. 3 is a diagram for explaining the operation of the pattern position detection device, and FIG. 4 is a plan view of the device used in the second embodiment of the present invention, FIG. 5A is a diagram showing the measurement procedure using a conventional spacing measurement device, and FIG. 5B
6 is a diagram showing the spacing measurement procedure using the apparatus shown in FIG. 4, FIG. 6 is a diagram showing the apparatus used in the third embodiment of the present invention, and FIG. 7 is a diagram showing the apparatus used in the fourth embodiment of the present invention. FIG. 8, which is a diagram showing the main parts, is a diagram for explaining the operation. 1,211,212,213,214...Magnetic head, 2,2A,2B...Transparent glass disk, 10,210...Magnetic head holding arm, 1
00,300...Xenon lamp, 110...Monochromator, 120...TV camera, 140
... Photodiode, 150 ... Television camera control circuit, 170 ... Pattern detection circuit, 20
1,202,203,204...Projector, 330
... Pinhole plate, 340, 340' ... Concave diffraction grating, 350 ... Line sensor, 400 ... Line sensor control circuit, 410 ... Sample hold circuit, 420 ... Timing control circuit, 430
...A/D conversion circuit, 440...Memory circuit, 4
50... Arithmetic control circuit, 500... Photodiode array, 510... Photocurrent amplification circuit, 520...
Comparator circuit, 530...Latch circuit, 54
0...Register, 550...Comparison voltage generator, 5
60...OR gate, 570...control circuit, 58
0...D/A conversion circuit, 590...digital display circuit.

Claims (1)

[Scope of Claims] 1. The floating spacing between the magnetic head and the magnetic recording medium is replaced by a transparent body for one of the floating slider of the magnetic head and the magnetic recording medium, and the floating spacing is removed through the transparent body. In the floating spacing measurement method, which uses the interference effect of light introduced into the magnetic head, white light is incident on the floating surface of the magnetic head while the transparent body replacing the magnetic recording medium is rotated. The reflected light from the floating surface is received, a planar image of the floating surface is detected using a voltage proportional to the intensity of the reflected light, the voltage is converted to a digital value as image information, and the image information is used to detect the planar image of the floating surface. obtaining position coordinate information of a desired portion of the image and determining floating spacing measurement position coordinates from the position coordinate information and information of a desired floating spacing measurement location in the floating surface; and replacing the magnetic recording medium. While rotating the transparent body, white light or monochromatic light from the same light source as the white light for determining the position coordinates is incident on the floating surface of the magnetic head, and the reflected light from the floating surface is used as the incident light. In the case of white light, it is separated into monochromatic light and detected, and if the incident light is monochromatic light, it is detected as is, and the floating spacing at the measurement position is measured using the interference effect of light. A method for measuring floating spacing, comprising: 2. Replace the magnetic recording medium with two disc-shaped transparent bodies, arrange the two transparent bodies at the same spacing as the spacing between the magnetic disks in the desired magnetic storage device, and replace each of the two transparent bodies. Claim 1: The floating spacing is measured by inserting a plurality of magnetic heads fixed to one holding arm between the two transparent bodies so that at least one magnetic head faces each other. Floating spacing measurement method described.