JPS63100606A - Method for discriminating exposing of organic insulator of magnetic head - Google Patents

Abstract

PURPOSE:To make non-destructive measurement by detecting the polarization characteristic arising upon passage of the fluorescence emitted by an org. material through a magnetic gap when light of a specific wavelength is projected to a magnetic head as an intensity ratio of the fluorescence in the oscillation direction components varying by 90 deg. from each other. CONSTITUTION:Light from an illuminating light source 12 enters a dichroic mirror (prism) 10 and only the light of the specific wavelength is reflected by a vapor deposited film filter of the mirror 10 and is directed toward an objective lens 9. The light of the other wavelengths is transmitted through or absorbed by the prism. The fluorescence of the specific wavelength is emitted from the magnetic had 1 when the light of the specific wavelength passed through the lens 9 is illuminated to the head 1. Said fluorescence is passed through the lens 9 and again through the mirror 10. The light of the reflected light component is shielded by the effect of the vapor deposited film filter on the prism surface and the light of the wavelength of the fluorescent component is transmitted therethrough. The transmitted fluorescent component is imaged onto a TV camera 16 by imaging lenses 13, 15. The light passage direction is made to coincide with the S direction by inserting a polarizing plate 14 in the imaging optical path. The measurement of the polarization condition when the exit light from an org. insulator 6 receives at the time of the passage through the magnetic gap 7 is permitted by rotating the same in the direction 90 deg. therewith.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for determining exposure of organic insulators in a magnetic head.
In particular, it relates to a method for determining exposure of organic insulators using the polarization characteristics of fluorescence.

[Conventional technology]

Regarding the shape of the magnetic head, we used Electronic Packaging Technology (εLaetrontcPa).
cka, qitsl TachntrLogy) V
oL 1, A 2 p 111-113 (1985
-7), etc., and there is a description of enlarging and viewing the internal pattern shape using a microscope through a transparent protective film on the surface. Since the cross-sectional shape of this turn cannot be seen without breaking the head, there has been no suitable method for non-destructively inspecting it.

[Problem that the invention seeks to solve]

However, in the above-mentioned prior art, the cross-sectional shape of the turns cannot be seen unless the head is broken, and no consideration is given to non-destructive inspection.

An object of the present invention is to enable non-destructive observation of the vicinity of the surface inside the head.

[Means for solving problems]

In order to achieve the above objective, we made it possible to observe the fluorescence emitted by an organic insulator, and by measuring the degree of polarization, we took advantage of the property that this fluorescence takes on polarization characteristics when passing through a slit-shaped magnetic gap. A special feature characterized in that it determines how close the organic insulator is to the surface of the head or whether it is exposed or not. To observe the fluorescence (light of a specific wavelength) of the organic insulator. To,
A means for irradiating the head with light of a specific wavelength is provided. When passing through the magnetic gap, the above fluorescence takes on polarization characteristics,
To measure the degree of polarization, a light receiving element detects the intensity of fluorescence in vibration direction components that differ by 90 degrees from each other, and calculates the intensity ratio to determine the distance to the head surface of the organic insulator or to the head surface. The presence or absence of exposure can be determined.

〔Example〕

Examples of the present invention are shown in FIGS. 1-6. FIG. 2 is a cross-sectional view showing the cross-sectional shape of the magnetic head. 1 is a magnetic head, and between an upper magnetic film 5 and a lower magnetic film 4 there is a transparent inorganic material 7 forming a magnetic gap and an organic insulating material 6 filling the space of the coil 5. These are formed on a substrate 8, and their surfaces are further protected with a transparent protective film 2.

Conventionally, the only way to measure the dimensions of each part of the head was to observe it with a microscope from the Y and Z directions in FIG. Since the three corner points do not completely coincide with each other, it is difficult to accurately measure the distance from the zero point to the sliding surface (three surfaces) t with an accuracy on the order of α1 μm. Furthermore, when the head is viewed from the Z direction as shown in FIG. 3, even if the organic insulator 6 is exposed on the surface (sliding surface), the organic insulator 6
．． Since the magnetic gap material 7 is a nearly transparent material, it is difficult to distinguish between them, and it is not possible to determine whether or not it is exposed to the surface of the organic insulator 60. The exposed shape of the organic insulator 6 is
In FIG. 3, the magnetic film has a parallel shape along the exposed tip portion 3-1. When this organic insulator 6 is exposed, the magnetic head 1
Since the sliding characteristics when sliding on the disk surface deteriorate, it is necessary to clearly determine whether there is exposure or not.

The present invention focuses on fluorescence observation as a method for distinguishing between the organic material 6 and the inorganic material 7. When illuminated with light of a certain wavelength (for example, green light) and observed with a specific light of a different wavelength from the illumination light (for example, red light; called fluorescence), inorganic materials do not emit fluorescence, but Organic materials emit distinct fluorescence. However, in FIG. 2, when the illumination light is applied from the objective lens 9 side, the fluorescence passes through the magnetic gap 7 of the transparent material and is visible on the surface even though the tip C of the organic insulator 6 is not exposed on the surface. Therefore, it is not possible to determine whether or not the organic insulator 6 is exposed just by seeing the fluorescence through the objective lens.

Therefore, in the present invention, it is possible to determine the presence or absence of exposure of organic insulators by fluorescence observation using the methods shown in FIGS. 1, 4, and 5.

In Fig. 1, light emitted from an illumination light source 12 passes through an illumination lens 11 and enters a dichroic mirror (prism) 10, and only light of a specific wavelength is reflected by the action of a vapor-deposited film filter applied to the reflective surface of the prism. Light of other wavelengths is directed toward the objective lens 9 and is either transmitted through the prism or absorbed. The light of a specific wavelength that has passed through the objective lens is sent to the magnetic head 1.
When illuminated, the magnetic head emits reflected light having the same wavelength as the illumination light as well as light (fluorescence) having a specific wavelength different from the wavelength of the illumination light. When these lights pass through the objective lens and pass through the dichroic mirror 10 again, the action of the vapor-deposited film filter applied to the prism surface blocks the reflected light component of the magnetic head, and the light with the wavelength of the fluorescent component is blocked. can be transmitted. The fluorescent component thus transmitted forms an image on the TV left camera 6 by the imaging lens 13.15. At this time, in the present invention, by inserting an analyzer (polarizing plate) 14 into the imaging optical path, the polarization state that the light emitted from the organic insulator 6 receives when it passes through the parallel slit-shaped magnetic gap 7 is measured. making it possible.

When the fluorescence passes through the parallel slit-shaped magnetic gap 7 in FIG. 3, the vibration component in the P direction in the figure is significantly attenuated, but the vibration component in the S direction along the slit direction is hardly attenuated. When the intensity ratio S/P of the fluorescence of the S component and the P component is measured, it is as shown in Figure 5, for example, and when the gap depth GD of the magnetic head (the distance from point 0 to A5B in Figure 2) is long, the intensity increases. It can be seen that the ratio becomes large, while when GD is 0 or less, the organic material is completely exposed on the surface, so the polarization characteristics of fluorescence almost disappear, and the intensity ratio converges to 1.

In order to measure this intensity ratio S/P, the polarizing plate 14 is inserted into the imaging optical path as shown in FIG. 1, and by rotating it around the optical axis, the light passing direction is changed and the S By matching the direction and rotating in the 90' direction, the component in the P direction can be detected.

In general, fluorescent light is weak, and the light that passes through a polarizing plate is attenuated, so sufficient light intensity cannot be obtained.

For this reason, in FIG. 1, the image addition processing circuit 17 cumulatively adds the TV image frames, improves the contrast of j1i@, and displays the image on the monitor TF 18. An example of the monitor image is shown in Fig. 4. On the same screen, the magnetic film 3-1.4-
When the luminance signal waveform on the vertical measurement line (broken line in the figure) across 1 is displayed, it becomes like the waveform on the left side of the figure, and the vicinity of the upper magnetic film of the magnetic gap becomes brighter. By comparing the brightness of this organic insulator fluorescence with the brightness of the reference portion of the screen, the brightness It can be detected as shown in FIG. When 1m is based on the brightness of the magnetic film part,
! , is the brightness based on the brightness of an arbitrary point on the substrate 8.

In the ms diagram, the fluorescence intensity ratio Sh is approximately 2 as the criterion value L0 for GD-0, but considering the data dispersion, Lo
Good products and defective products (those with exposed organic material) can be determined based on the reference value <L+.

Here, the thickness α of the magnetic gap (Fig. 6) is approximately 1 μm or less, but even if α is somewhat large, if the overall image magnification is sufficiently increased with a high-power objective lens, the depth of focus will be shallow. When the refractive index of the magnetic gap material 7 is n = 164, the fluorescence emitted from point C of the organic material has a total reflection angle θ of approximately 37° on one surface, which means that the fluorescence emitted from point C of the organic material enters the objective lens in the form of a slit, regardless of the width of a. Since the width (kud) of the light is determined, the polarization characteristics described above can be obtained.

Considering the variation in fluorescence due to organic materials, the intensity ratio S
It is convenient for comprehensive judgment to be able to check the brightness of the entire fluorescence when the polarizing plate 14 is removed from the imaging optical path at the same time as /P.

Further, in the present invention, the illumination light of the magnetic head can be irradiated from any other direction without passing through the objective lens 9.

〔Effect of the invention〕

According to the present invention, it has become possible to simultaneously determine the gap depth of the magnetic head and the presence or absence of exposure of the organic insulator, making it possible to perform non-destructive measurement.

[Brief explanation of the drawings] Figure 1 is a configuration diagram showing the configuration of an apparatus for measuring the polarization characteristics of fluorescence, Figure 2 is an explanatory diagram showing the cross-sectional shape of the magnetic head and the objective lens, and Figure 3 is the magnetic An explanatory diagram of the head viewed from the sliding surface side, Fig. 4 is an explanatory diagram showing the luminance signal waveform of fluorescence on a high quality data screen, and Fig. 5 is a relational diagram showing the relationship between polarization characteristics of fluorescence and gap depth GD. , FIG. 6 is an explanatory diagram showing the total reflection characteristics of fluorescence in the magnetic gap portion. 1・・・・・・・・・・・・・・・・・・Magnetic head 2
・・・・・・－・・・・・・・・・・・・Protective film 3.4・・
......Magnetic film 5...
・・・－・・・Coil 6・・・・・・・・・・・・・・・・・・
・Organic insulator 7・・・・・・・・・・・・・・・・・・・Magnetic gap 8・・・・・・・・・・・・・・・・・・・・Substrate 9・・・・・・・・・・・・・・・−・Objective lens 10
゛°゛°・・・・－・・・・・・Guicroic Mira 11
...Song...Lighting lens 12...
・・・・・・−・Illumination light source 13.15・・・・・・・・・
・Image is formed 14...Polarizing plate (analyzer) 16...TV
Left camera 7...--Image addition processing device 18°゛・No. 1...--Monitor TV/""""1
＼ Agent Patent Attorney Masaru Ogawa 11 Figure π3 4th indentation

Claims (1)

[Claims] 1. When the surface of the magnetic head is irradiated with light of a specific wavelength, the fluorescence emitted by the organic matter is observed, and the polarization characteristics that occur when this fluorescence passes through the magnetic gap are determined by the above-mentioned polarization characteristics of vibration direction components that differ by 90 degrees from each other. A method for determining exposure of an organic insulator in a magnetic head, characterized by detection as a fluorescence intensity ratio.