JPH109831A - Flying height measuring device for magnetic recording devices - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: To measure flying height of a magnetic head slider in a magnetic recording apparatus without using special processing on a slider or other magnetic head support system when using an FTR to measure the flying height of the slider. Provide equipment. An insulating film that shields a magnetic head and a slider is used as an optical path of a flying height sensor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a flying height measuring device for a magnetic recording device.

[0002]

2. Description of the Related Art As a prior art, Japanese Patent Application Laid-Open No. 3-212868 discloses an apparatus in which a sensor in which all of a light emitting section, an optical path and a light receiving section are optically integrated is mounted on a magnetic head slider. . As another method, as described in JP-A-3-054055, only a light path is mounted on a magnetic head slider, and a light emitting unit and a light receiving unit are installed outside the apparatus.
A device for connecting an optical path to a light emitting unit and a light receiving unit by an optical fiber is introduced.

[0003]

Since the flying height measuring apparatus using the FTR can constitute a sensor on the slider, the flying height measuring apparatus can measure the absolute value of the flying height, and can be used during the magnetic head positioning operation (seek operation). This is advantageous over the optical interference type floating tester conventionally used in that the behavior can be measured during operation) and the measurement can be performed using a combination of an actual disk and an actual slider. However, conversely, since it is necessary to mount the sensor on the slider, it is necessary to perform special processing on the slider.

SUMMARY OF THE INVENTION An object of the present invention is to provide a flying height measuring apparatus capable of forming a sensor using an FTR into an actual slider without specially processing the slider.

[0005]

In order to achieve the above-mentioned object, the present invention does not newly construct a flying height sensor, but instead forms an insulating film 3 for shielding between a slider 1 and a magnetic head 2 as shown in FIG. Is used as the optical path of the flying height sensor.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a side view showing the overall configuration, and FIG. 2 is a diagram showing a main measurement part in FIG. FIG. 3 is a front view of FIG. Next, components of FIGS. 1 to 3 will be described. 1 is a slider on which the magnetic head 2 is mounted, 5 is a spindle motor for fixing and rotating the magnetic disk 4, 7 and 8 are collimator lenses for collimating the beam diameter of the light beam 6 to the value of the radius of the magnetic disk 4, and 9 is a light beam 6 Is a prism coupler that makes a part of the incident light 11 incident on the insulating film 3, 10 is a prism coupler that emits the incident light 11 from the insulating film 3 as the measuring light 13, and 12 is a reference light that is reflected at the boundary between the prism coupler 9 and the slider. , 14 are polarizers, 15 and 16 are photodetectors, 17 is photodetector 1
Reference numeral 18 denotes a load arm for supporting the slider 1.

The operation of the first embodiment of the present invention configured as described above will be described. In FIG. 1, slider 1
Is floating above the rotating magnetic disk 4 attached to the spindle motor 5. The slider 1 has prism couplers 9 and 10 mounted thereon. The light flux 6 is collimated by collimator lenses 7 and 8 so that the light flux becomes parallel light within the radius of the magnetic disk 4.
As shown in FIG. 2, the light of the light flux 6 incident on the reflection surface 9a of the prism coupler 9 is incident on the insulating film 3 shielding the magnetic head 2 and the slider 1 and the boundary between the prism coupler 9 and the slider 1. Splits into light reflected by Of the light, the light reflected at the boundary between the prism coupler 9 and the slider 1 is selected by the polarizer 14 only for a certain polarization plane as the reference light 12, guided to the photodetector 15, and converted into an electric signal E ₁ .
The light incident on the insulating film 3 is incident at an incident angle θ such that the light is totally reflected by the measuring unit 3a. The light reflected by the measuring portion 3a is emitted by the prism coupler 10, is converted into an electric signal E ₂ to select only the same polarization plane as the reference light 12 by the polarizer 14 and incident on the light detector 16 as measurement light 13 . At this time, the evanescent wave is seeping out to the air side at the boundary between the measurement unit 3a and the air to the region of the wavelength of light. When the flying height of the measuring unit 3a and the magnetic disk 4 is sufficiently large, the light is totally reflected. However, when the flying height becomes less than the wavelength of the light and reaches the area where the evanescent wave has permeated, the light is absorbed by the magnetic disk 4. As shown in FIG. 4, the light amount changes with respect to the flying height. This optical phenomenon is called FTR. Conversely, the flying height can be measured by measuring the amount of reflected light. However, only by measuring the change in the amount of light of the measuring light 13, the light flux 6
If the light amount itself changes, it directly becomes a measurement error. Further, in order to measure the behavior when the slider performs a seek operation, the beam diameter of the light beam 6 is changed to the magnetic disk 1.
However, since the light normally has a Gaussian distribution in the plane, the amount of light incident on the prism coupler 9 changes when a seek operation is performed, which also causes a measurement error.
Therefore, as described above, the prism coupler 9 is shaped like a diamond and the light reflected at the boundary with the slider 1 is used as the reference light 12.
The measurement error can be eliminated by determining the ratio E ₂ / E ₁ to the measurement light 13 by the flying height calculation circuit 17 using the above.

Next, a second embodiment will be described with reference to FIG. FIG. 6 is a side view of the flying height measuring device for explaining the second embodiment. 19 is a polarizing beam splitter, 20 to 2
3 is a photodetector, 24 and 25 are flying height calculation circuits, and 26 is a judgment unit. The components before the polarization beam splitter are the same as those in the first embodiment described above, and a description thereof will be omitted.

The operation of the second embodiment of the present invention configured as described above will be described. Until the reference light 12 and the measurement light 13 are taken out in this embodiment, it is the same as in the first embodiment, and a description thereof will be omitted. The reference light 12 is separated into S-polarized light and P-polarized light by a polarization beam splitter 19, and guided to photodetectors 20 and 22, respectively, to receive electric signals E _P1 and E _S1.
Is converted to The measurement light 13 is also separated into S-polarized light and P-polarized light by the polarization beam splitter 19 in the same manner as the reference light 13 and guided to the photodetectors 21 and 23, respectively, and the electric signals E _P2 and E _{S2 are obtained.}
Is converted to The flying height calculation circuit 24 calculates the reflectance E _P2 / E _P1 for P-polarized light, and the flying height calculation circuit 25 calculates the reflectance E _S2 / E _S1 for S-polarized light. When both the P-polarized light and the S-polarized light are used in this manner, as shown in FIG. 4, the P-polarized light having a high measurement sensitivity with respect to the flying height becomes the minimum flying height before the flying height becomes zero, and two reflectances are obtained with one reflectance. The area where two flying heights exist can be determined by the determination unit 26 using S-polarized light.

[0010]

According to the present invention, since the slider and the insulating film for shielding the magnetic head are used as the optical path of the sensor measuring section, except for mounting the prism coupler on the slider, the magnetic head support including the slider is supported. It is possible to measure the flying height with high accuracy without having to perform any processing on the system. Further, since the magnetic head and the flying height sensor are integrated, the relationship between the R / W signal and the flying height can be measured at once.

[Brief description of the drawings]

FIG. 1 is a side view illustrating a first embodiment of the present invention.

FIG. 2 is a side view showing a main measurement part in FIG.

FIG. 3 is a front view of FIG. 1 and a perspective view of the present invention.

FIG. 4 is a diagram showing a relationship between a flying height and a reflectance.

FIG. 5 is a side view showing a means for solving the problem.

FIG. 6 is a side view illustrating the first embodiment of the present invention.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 slider, 4 magnetic disk, 5 spindle motor, 6 luminous flux, 7 8 collimator lens, 11 incident light, 12 reference light, 13 measurement light, 14 polarizer, 1
5, 16: photodetector, 17: flying height calculation circuit.

Claims (2)

[Claims] In a measuring apparatus utilizing an evanescent wave generated when light is totally reflected, a slider and an element constituting a thin film magnetic head are insulated as means for measuring the flying characteristics of a magnetic head slider of a magnetic recording apparatus. A flying height measuring device for a magnetic recording device, wherein a flying height sensor is used by using an insulating film to be used as an optical path. 2. A flying height of a magnetic recording apparatus according to claim 1, further comprising means for separating light incident on the prism coupler into reference light and measurement light to remove a measurement error due to a light amount fluctuation and a light amount distribution. measuring device.