JPS60154313A - Vertical magnetic recording magnetic head - Google Patents

Abstract

PURPOSE:To widen the operating frequency band without lowering the reproducing sensitivity by making the resonance frequency decided by the inductance and stray capacitance of the winding coincident with a dip frequency of a reproduced output so as to attain recording at high frequencies without decreasing the number of turns of the winding. CONSTITUTION:The resonance frequency f1 due to the inductance and stray capacitance of the winding 22 of an auxiliary magnetic pole 21 of a vertical magnetic recording magnetic head 20 is made coincident with the minimum frequency of the dip frequency of the reproduced output voltage at the normal state of the magnetic head 20. Then a reproducing signal produced in the winding 22 of the auxiliary magnetic pole 21 at the reproducing mode is separated into a luminance signal and color signal by a branching filter 27 via the reproducing position contact 19b of a changeover switch 19 and a reproducing amplifier 26, and FM-demodulated by FM demodulators 29, 31 via an equalizer 28. The luminance signal and the color signal frequency-converted by a frequency converter 32 are transmitted as the reproducing signal via a mixer 33. Since the dip is compensated, the operating frequency band is winded.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a magnetic head for perpendicular magnetic recording that performs recording on a disk-shaped or tape-shaped magnetic recording medium by perpendicular magnetization, and particularly relates to a magnetic head for perpendicular magnetic recording that performs recording on a disk-shaped or tape-shaped magnetic recording medium by perpendicular magnetization. This invention relates to a means for setting a resonance frequency.

[Prior art]

Generally, it is known that a magnetic head generates resonance due to the inductance and capacitance of the winding during recording or reproduction, and the impedance becomes extremely large at the resonance frequency. Even in perpendicular magnetic recording, resonance occurs in a winding, for example, an auxiliary magnetic pole, and it is difficult to flow a recording current at the resonance frequency.

Therefore, in the past, as shown in FIG. 1(a), only the low frequency band A below the resonance frequency f1 was used, and recording in the high frequency band B was not possible.

In addition, as a means to enable recording in a high frequency band, the number of turns of the winding applied to the magnetic pole is reduced, and the number of turns of the winding wire applied to the magnetic pole is reduced.
) with impedance characteristics as shown by the dashed line,
There is a way to set the resonance point to 2 at a higher frequency. However, when the number of turns of the winding is reduced as described above, the reproduction sensitivity inevitably decreases, and a decrease in the performance of the magnetic head is unavoidable.

On the other hand, for example, on the main pole side where no winding is applied, specific frequencies fa and fc are applied as shown in FIG. 1(b).
. . ., the reproduced output voltage E has data portions da and dc.
... occurs. The occurrence of the dip parts da and dc is as follows:
This is due to the relationship between the film thickness of the main pole and the recording wavelength, and this point will be discussed later. The above dip frequencies fa, f
When c... is included in the recording frequency band A shown in FIG. 1(a), the band above the dip frequency fa in the recording frequency band A becomes virtually unusable. In other words, the reproduced output voltage E shown in FIG. 1(b)
Only the band of line method peak P1 can be used, and the secondary peak P2
A problem arises in that the bandwidth cannot be used effectively.

FIGS. 2(a), 2(b), and 3(c) are diagrams showing the cause of the occurrence of the dip portion. Figure 2 (a) (b) (c)
As shown in , the recording wavelength (the pitch of the magnetized regions shown by the arrow) in the magnetic recording medium 1 is
Considering the case where the recording wavelength changes as 1/2.1/3.1/4, when the recording wavelength is 1 for an even valve with a film thickness W, the magnetic field generated from the magnetic recording medium 1 has no direction inside the main magnetic pole 2. Since the opposite occurs, they cancel each other out, and the apparent reproduction output voltage E exhibits the state shown in FIG. 2(C) at the frequencies fa and fC, as shown in FIG. 3, at a dip portion da.

dc occurs.

The specific recording wavelength λd that forms the dip portion and the film thickness W of the main magnetic pole 2 are λd=W/(2n-0,3) (n=1.2°3...
)...(1) There is a relationship. Also, the recording wavelength λ and the recording frequency f are:
If the relative speed between the magnetic head and the recording medium is V, then there is the following relationship: λ-V/f (2). Therefore, from the above equations (1) and (2), the recording frequency fd that causes the dip portion and the film thickness W of the main magnetic pole 2 are W = (2n-0, 3)V-1/fd = (3) have a relationship

Here, the resonant frequency fo of the auxiliary magnetic pole is the dip frequency fd
If the film thickness WO of the main magnetic pole is made to match, the film thickness WO of the main magnetic pole at that time can be expressed as WO=(2n-0,3)V-1/fo·(4).

〔the purpose〕

The present invention was made in consideration of these circumstances, and its purpose is to enable recording in a high frequency band without reducing the number of turns of the winding wire □ applied to the magnetic pole, and to reduce the reduction in re-intermediate sensitivity. An object of the present invention is to provide a magnetic head for perpendicular magnetic recording that can be used to widen the frequency band without causing problems.

〔overview〕

In order to achieve the above object, the present invention is characterized by the following configuration. That is, the resonant frequency related to both the inductance of the winding wound around the auxiliary magnetic pole or the main magnetic pole in the magnetic head for perpendicular magnetic recording and the capacitance due to stray capacitance etc. related to the winding is determined by the dip of the reproduction output in the normal use state of the magnetic head. It is characterized by substantially matching the frequency.

〔Example〕

FIG. 4 is a block diagram showing the circuit configuration of a recording/reproducing thread in an embodiment of the present invention. In the recording mode, the luminance signal Y input to the terminal 11 is converted into FM by the FM modulator 12.
The modulated color signal C input to the terminal 13 is FM modulated by the FM modulator 14 . Both FM modulated signals are mixed by a mixer 15 and converted by a limiter 16 into a rectangular wave having a predetermined voltage level. This rectangular wave is amplified by the recording amplifier 17 to a recording current of 100 mAll)-1), and then sent to the constant current circuit 18 with a maximum output voltage of 4
The recording signal has a constant current of 0VI)-p, 100mAI)-1). That is, the auxiliary magnetic pole 21 described below
This results in a signal with a constant current that is independent of the impedance of the current. This signal is passed through the recording side 19a of the changeover switch 19 to the auxiliary Iflt in the magnetic head 20 for perpendicular magnetic recording.
ili 21 rolls 1m 221: Supplied. A main magnetic pole 23 is disposed opposite to the auxiliary magnetic pole 21 with a disk-shaped magnetic recording medium 24 in between. Therefore, the recording signal is perpendicularly magnetically recorded on the magnetic recording medium 24 which is rotated at a constant speed by the motor 25.

In the reproduction mode, the reproduction signal induced in the winding of the auxiliary magnetic pole 21 is supplied to the reproduction amplifier 26 via the reproduction side 19'b of the changeover switch 19, where it is amplified. This amplified reproduction signal is frequency-separated by a duplexer 27,
It becomes a luminance signal and a color signal. Brightness signal is equalizer 2
8 to the FMM modulator 29 for FM demodulation.

The color signal is supplied to an FMM modulator 31 through an equalizer 30 and subjected to FMM modulation. The FMtilm luminance signal and the color signal, which has been FM demodulated and frequency-converted by a frequency converter 32, are mixed in a mixer 33 to form a reproduced video signal, which is sent out from an output terminal 34.

By the way, as shown in FIGS. 5(a) and 5(b), the resonance frequency f1 of the winding 22 of the auxiliary magnetic pole 21 in the perpendicular magnetic recording magnetic head 20 is adjusted to the above-mentioned level due to both its inductance and capacitance due to stray capacitance. The minimum dip frequency fa of the dip frequencies fa, fC, . . . of the reproduction output voltage E in the normal use state of the magnetic head 20
is set to substantially match .

Here, the normal use state means that a floppy disk with a diameter of 3 inches is used as the magnetic recording medium 24, the rotational speed of the floppy disk is 360 rpm, the relative speed with the magnetic head 20 is 11.3 ms, and the film thickness of the main magnetic pole 23 is is 1.0 μm and the recording density is 50 KBPI.

Therefore, the resonant frequency f1 at which no reproduced output voltage E occurs
This means that there is no need to flow a recording current. Furthermore, since the impedance of the auxiliary 11 poles 21 in each band of the linear peak P1 and the secondary peak P2 of the reproduction output voltage E is sufficiently low, it is easy to flow the recording current. Therefore − next beak P
Not only can recording be performed well in the band P1, but also recording can be performed in the band of the secondary peak P2.

When performing perpendicular magnetic recording, it is ideal to use a rectangular wave recording current as described above, but in this case a wide frequency band is required to perform high density recording. According to this embodiment, as described above, the band of the secondary peak P2 can also be used as a recording band, so that high-density perpendicular magnetic recording using a rectangular wave can be performed.

FIG. 6 is a diagram showing the situation. As shown in FIG. 6, when the dip frequency, that is, the resonance frequency is 20 MHz, an FM modulated color signal C is recorded around IOMH2 in the -order peak P1 band (DC to 20 MH2),
30 M in the band of secondary peak P2 (20-40 MHz)
It becomes possible to record FM modulated luminance signal sound centering on HZ.

As a result, the band becomes significantly wider than the conventional case in which only the band of the -order peak P1 is used, and high-density recording can be easily performed.

FIG. 7 shows a specific example of the impedance/frequency characteristics of the auxiliary magnetic pole 21. As is clear from FIG. 7, the maximum output voltage of the constant current circuit 18 is 40Vp with respect to the auxiliary magnetic pole 21.
-I), constant current 100mAp- up to 400Ω
I) can flow.

That is, it becomes possible to record in a frequency band other than the 17-23 MHz band, and a wider band can be achieved.

In perpendicular magnetic recording, the phase of the reproduced signal is inverted by 180 in the band of the secondary peak P2, but in the band of resonance frequency 20 MH2 or more shown in FIG. 7, the phase characteristics in the reproducing circuit system are changed by 180. When viewed as a whole, there is no change in phase, which is convenient.

As described above, in this embodiment, since the dip frequency at which no reproduction output occurs matches the resonance frequency of the auxiliary magnetic pole 21, recording at the above frequency is unnecessary, and the linear peak P1 of the reproduction output voltage is Recording and reproduction can be performed using almost the entire region of each band of the secondary peak P2. Therefore, a very wide frequency band can be obtained, making it suitable for performing high-density perpendicular magnetic recording. Furthermore, since there is no need to reduce the number of turns of the winding 22 of the auxiliary magnetic pole 21 in order to increase the resonance frequency, there is no risk of deterioration in reproduction sensitivity.

Note that the present invention is not limited to the above embodiments. For example, in the embodiment described above, the present invention was applied to a magnetic head in which the auxiliary mtU 21 was provided with a winding 22, but it is of course also applicable to a magnetic head in which the main pole 23 is provided with a winding. . Of course, various other modifications can be made without departing from the gist of the present invention.

[Effects of the Invention] According to the present invention, the auxiliary magnetic pole or the main magnetic pole in a magnetic head for perpendicular magnetic recording can be used as an auxiliary magnetic pole or a main pole. The resonant frequency associated with both the inductance of the winding applied to one pole and the capacitance due to the stray capacitance and shade related to the winding is made to substantially match the dip frequency of the reproduction output in the normal use state of the magnetic head. , it is possible to provide a magnetic head for perpendicular magnetic recording that enables recording in a high frequency band without reducing the number of turns of the winding wire applied to the magnetic pole, and that can widen the usable frequency band without reducing playback sensitivity. .

[Brief explanation of drawings]

Figures 1 (a) and (b) to Figure 3 are diagrams for explaining the problems of conventional magnetic heads. Figures 1 (a) and (b) show the resonance frequency characteristics of the auxiliary magnetic pole and the reproduction output voltage Figures 2(a) to (C) and 3 are diagrams illustrating the state of occurrence of the dip, and Figures 4 to 7 are diagrams for explaining the cause of the occurrence of the dip.
The figure shows an embodiment of the present invention, FIG. 4 is a block diagram showing the circuit configuration of the recording/reproducing system, and FIGS. 5(a) and 5(b) show the resonance frequency of the auxiliary magnetic pole and the dip frequency in the reproduction output voltage. FIG. 6 is an explanatory diagram of the frequency band used, and FIG. 7 is a diagram showing the frequency vs. impedance characteristic of the auxiliary magnetic pole. DESCRIPTION OF SYMBOLS 1... Magnetic recording medium, 2... Main magnetic pole, 20... Magnetic head for perpendicular magnetic recording, 21... Auxiliary magnetic pole, 22...
...Winding, 23...Main magnetic pole, 24...Disk-shaped magnetic recording medium, 25...Motor. Applicant's agent Patent attorney Jun Tsuboi Figure 4jj"'nee Figure 5

Claims (1)

[Claims] In a magnetic head for perpendicular magnetic recording in which the auxiliary magnetic pole or the main magnetic pole is wound with a wire, the resonant frequency related to both the inductance of the winding and the capacitance due to stray notes related to the winding, etc. 1. A magnetic head for perpendicular magnetic recording, characterized in that the dip frequency of the reproduction output substantially matches the dip frequency of the reproduction output.