JPS6278706A - Magnetic head device - Google Patents

Abstract

PURPOSE:To suppress the deterioration of the frequency characteristics due to the increase of the jumping noises, the stray capacity and the lead inductance, by setting a step-up transformer between heads and therefore obtaining a reproduction system in a wide band and with low noises. CONSTITUTION:To step-up transformers 31 and 32 for reproduction are attached on an attachment base 7 via an insulated layer in order to reproduce two channels. Here a composite head 6 is fixed at an end of the base 7. Both transformers 31 and 32 are covered by magnetic shielding cases 33 and 34. Thus the distances are minimum between the head 6 and both transformers 31 and 32. This reduces greatly the noises and improves the S/N together with the minimum wiring resistance. As a result, the frequency characteristics can also be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic head device for a magnetic recording/reproducing device used, for example, in an electronic camera for recording still images or a disk device for recording digital data. Related to improvements in magnetic head structure.

(Prior Art) In conventional magnetic recording and reproducing devices, especially magnetic recording and reproducing devices for small electronic cameras, a recording deck and a reproducing deck are usually provided separately.However,
If the recording deck and the reproducing deck are separated, it is impossible to satisfy the desire to immediately reproduce recorded images, etc., and to re-record immediately if there is a problem. The same holds true for digital data recording. As a way to improve this point to some extent, a magnetic recording/reproducing device that uses a recording/reproducing head that integrates a recording head and a reproducing head and incorporates a recording/reproducing circuit has been developed and put into practical use. . According to this magnetic recording/reproducing device, digital data can be immediately reproduced and re-recorded after recording, but image information cannot be re-recorded because an erasing head is not incorporated. The main reason why an erase head is not built into the above devices is that in the case of digital data recording devices, there is no need for an erase head because so-called override is possible, and in the case of small electronic cameras, all parts are miniaturized. , Compactness is required, and the space for installing components is extremely limited, so it is difficult to incorporate an erasing head that requires a relatively large installation space due to space considerations. In addition, in a device that uses a magnetic disk with a diameter of about 2 inches as a recording medium, when an erasing head is installed together with a recording/reproducing head, it is extremely difficult to set the head position so that a good head touch can be obtained for both heads. . In particular, when performing high recording density recording where the recording wavelength is on the order of 0.5 μm or less, it is necessary to minimize the spacing loss caused by the quality of the head touch of each head. High recording density recording is difficult because it is difficult to achieve good rad touch. Furthermore, in the case of image recording, there is a frame recording mode that uses two tracks, but in this case, two erasing heads are required in addition to two playback heads, so a total of four heads can be used on one deck. II must be placed within a limited space. Therefore, in this case, the above-mentioned difficulties become even more pronounced. Since there are various difficulties in incorporating an erasing head as described above, the current situation is that image information is erased all at once using a separate erasing device. Therefore, the above-mentioned desire to re-record immediately after reproduction has not yet been satisfied.

On the other hand, as a countermeasure when the head output is insufficient, or when using an FE lower in the first stage of a reproduction amplifier,
Generally, a step-up transformer is used for playback, but the transformer is usually installed outside the base that supports the head chip, and is connected to the head chip with an appropriate signal line. It has become. However, the above-mentioned devices tend to pick up noise in the signal line portion, and the resistance of the signal line deteriorates frequency characteristics.

[Problems to be Solved by the Invention] Therefore, the present invention solves the problem of using a large-sized antenna with good S/N and frequency characteristics, even if the spacing loss is relatively large due to insufficient contact. In addition to being able to obtain playback output, recording and playing back various information such as image information well, and making instant re-recording possible, it is also possible to obtain a playback system with a particularly wide band and low noise, eliminating jump noise and It is an object of the present invention to provide a small and easy-to-manufacture magnetic head device that can suppress deterioration of frequency characteristics due to increases in stray capacitance and lead inductance.

C. Means for Solving Problems] The present invention is characterized by taking the following measures in order to solve the above problems and achieve the objectives.

That is, a head chip is mounted on the base, and the head chip is switched to a recording system or a reproducing system by a recording/reproducing switch circuit. When the head chip is connected to the recording system by this recording/reproduction switching circuit, a recording current is amplified and supplied to the head chip by a recording amplifier. Further, in a state where the head chip is connected to the reproduction system by the recording/reproducing switch circuit, the level of the signal picked up by the head chip is boosted by a step-up transformer installed on the base, and the boosted signal is is amplified by a differential input regenerative amplifier. Then, the previous recording/re-switching switch circuit, the recording amplifier, and the differential input amplifier are formed into a hybrid IC and mounted on the base.

The head chip is preferably a composite magnetic head formed by bonding a plurality of thin film heads such that each head gap is arranged at a predetermined interval in the track width direction. Further, it is desirable that the step-up transformer is equipped with a shield case.

(Function) By using a differential input amplifier as a regenerative amplifier and providing a step-up transformer between the head and the head, a wide-band, low-noise reproducing system can be obtained. Furthermore, since the recording/reproducing switch circuit, the recording amplifier, and the reproducing amplifier are hybridized and mounted on the base, it is possible to suppress deterioration of frequency characteristics due to increased noise, stray capacitance, and lead inductance.

〔Example〕

First, the basic configuration other than the main parts of the present invention will be explained with reference to FIGS. 1 to 8. FIGS. 1 and 2 are a schematic diagram and a head structure diagram in an embodiment of the present invention. 1st
1 in the figure is a rotating magnetic disk, and a motor (not shown)
3 in the counterclockwise direction as shown by the arrow, centering on the 0 point.
Rotates at a rotation speed of 60 ORPM (for NTSC). A composite magnetic head (
(hereinafter abbreviated as composite head) 2 records track T1.
．． T2... are formed concentrically. Disc 1 above
At one point on the outer circumference of the hub 3 located at the center of
A PG yoke 4 is provided as an index for detecting the rotational position of the disk 1. On the other hand, at one point on the rotation locus of the PG yoke 4 on the device main body side, a PG as a pulse detection means is installed.
A coil 5 is provided. This PG coil 5 is arranged on the non-recording surface side of the magnetic disk 1, that is, on the opposite side from the composite head 2, and when the magnetic disk 1 rotates, the PG coil 5
A pulse signal induced by interlinking with the magnetic flux generated by the G yoke 4 is extracted.

By the way, when recording still image information on the magnetic disk 1, when performing field recording, still image information of separate fields is recorded on tracks T1 and T2, and when performing frame recording, still image information of separate fields is recorded on tracks T1 and T2. Two consecutive fields of still image information are recorded. In either case, the start and end points of recording are the point when the PG yoke 4 reaches the position shown in FIG. 1, that is, the line connecting the center point O of the magnetic disk 1 and the center of the PG coil 5.

When Y-Y', this is when the PG yoke 4 arrives on the O-Y line. That is, at this time, the composite head 2 is switched by the PG pulse obtained in the PG coil 5. In the case of image recording, considering NTSC signals, 262H (horizontal line) signals are recorded on one track, but the switching point at this time is, for example, 7H before the leading edge VS1 of the vertical synchronization signal VS. be. Therefore, the leading edge VS1 of the vertical synchronization signal S is recorded at an angle o-o' shifted by θ (360° x (7/262>) from the 0-Y line, which is the switching point on the magnetic disk 1. As a result, the noise component generated at the switching point is located near the edge of the screen and can be substantially ignored.

FIG. 2 is a plan view showing the external structure of the composite head 2 shown in FIG. This composite head 2 has track T1. T2
On the other hand, various types of information such as image information or digital data can be continuously recorded or reproduced without moving the head, and the recorded information can be erased at any time. In other words, this composite head 2
A first recording/reproducing gap R/W-1 and an erasing gap E1 matching the track, for example, T1 are provided spaced apart in the track longitudinal direction, and a second track, for example, T2
Second recording/reproducing gaps R, /W-2 and erasing gap E2 matching the above are similarly provided spaced apart in the longitudinal direction of the track. Note that the composite head 2 has a 2-track recording/reproducing head 2A on the left side of the Y-Y' line, and a portion of the recording/reproducing head 2A on the left side of the Y-Y'
The two-track erase head 2B on the right side of the line is provided independently, and these are integrally joined with a crosstalk prevention magnetic shield member 2C in between, and the head is fixed to the base 2D. This can be achieved by In the figure, P is the track pitch, Wa is the recording/playback track width, w
b indicates the erase track width. Then, by attaching this composite head 2 to the main body of the device so that the joint part, which is the head center, is on the O-Y line in FIG. It is possible to make the four gaps, ie, erase gaps El and E2, touch the recording surface of the magnetic disk 1 to the same degree. In this way, a single head can be used, and when it is incorporated into an electronic camera, it can be handled in the same space as the previous one, and it can also be used for recording, recording, etc.
Reproduction and erasure can be performed appropriately at any time.

In the head configuration examples shown in FIGS. 1 and 2 above, the recording/reproducing gaps R/W-1, R/W- of the composite head 2 are
2 is slightly shifted laterally from the Y-Y' line. Therefore, the switching point is shifted by the shift width D1, and when the composite head 2 moves in the disk radial direction, the inclination angle of the gap with respect to the track changes, resulting in a change in the azimuth angle. To avoid this, the recording/reproducing gap R/W-1°R/W-2
It is difficult to manufacture because it needs to be slightly inclined with respect to the Y-Y' line. Furthermore, since a magnetic shield 2G for preventing crosstalk is interposed on the head joint surface, the recording/reproducing gaps R/W-1, R/W-2 and the erasing head E1.
The distance D2 from E2 also increases. Therefore, it is relatively difficult to obtain the best helad touch.

FIGS. 3 and 4 are a schematic diagram and a head structure diagram showing another example of the head configuration in which the problems of the above-described example of the head configuration are corrected. The overall configuration is the same as the examples shown in FIGS. 1 and 2, but in this head configuration example, the recording/reproducing gaps R/W-1 and R/W-2 of the composite head 6 are provided at the head center. , erasure gap E1. E2 is located upstream of the upper recording gap R/W-1 and R/W-2.
It is located at a different position. The head touch is set to be best on the line of the recording/reproducing gaps R/W-1 and R/W-2.

Therefore, according to this example of the head configuration, the head touch is better than that of the above-described example of the head configuration, spacing loss during recording and reproduction is reduced, and performance is improved. On the other hand, the erasure gap E1. E2 is recording/reproducing gap R/W -1, R/W -
Head touch is worse than in case 2, but since the erase gap width is larger than the recording/reproducing gap width, a slight performance deterioration can be tolerated.

In addition, as will be explained later, the recording operation is performed once per rotation of the disk.
Although the erasing operation is limited to one time, the erasing operation may be performed continuously while the disk 1 rotates a plurality of times, so that the erasing gap E1. It can fully compensate for E2's poor Herad touch.

Especially in this head configuration example, the recording/reproducing gap F</
Since W-1 and R/W-2 are on the Y-Y' line, even when the composite head 6 moves in the radial direction of the disk 1, the gaps R/W-1 and R with respect to the track are
/W-2(7)g! No change occurs in the angle (7 angles). Therefore, there is an advantage that no azimuth loss occurs. Note that the erasure gap E1. E2 has almost no effect on the azimuth angle for the reasons mentioned above, so the recording/playback gap R/W
-1 and R/W-2. Therefore, manufacturing is easier than in the above-mentioned head configuration example.

In addition, in order to improve head touch etc., it is better to keep the distance X between the recording/reproducing heads R/W-1, R/W-2 and the erasing heads E1, E2 as small as possible, and the magnetic shield 6C on the joint surface should also be It is sufficient to make it as thin as possible, but if this is done, a problem arises in that the glue between the recording/reproducing gaps R/W-1, R/W-2 and the erasing gaps El, E2 is 0 stalk. However, as will be described later, the problem of crosstalk can be solved by appropriately setting the timing of recording and erasing.

Incidentally, it is generally considered that a thin film head is desirable as a multichannel head with less crosstalk. As a thin film head for recording/reproduction, for example,
Giken Report, VR63-8, P55-60, (59,6,
21>r Thin Film Head for High Density Magnetic Recording Sheets" is known. However, even if it is possible to make the recording/reproducing head 1111, it is extremely difficult to make the erasing head which should be combined with this recording/reproducing head 11.

The reason for this is that when erasing a 7M To luminance signal recorded on a metal disk with a coercive force of -1 cm and 1400 millimeters, a magnetizing force of 2 amperes or more is required, but thin film This is because it is difficult to increase the number of turns in the head coil, and the cross-sectional area of the coil is also large, making it difficult to obtain large ampere turns.Also, in order to manufacture a core that passes a large magnetic flux, it is difficult to increase the number of turns. It is necessary to increase the cross-sectional area of the thin film head, but since the core is formed by sputtering or the like in a thin film head, it takes a long time to manufacture a core with a large cross-sectional area, which poses a problem in terms of loss.

FIGS. 5 and 6 are diagrams showing a composite head constructed in consideration of such circumstances. As shown in FIG. 5, the composite head 6 is mounted and fixed to the end of the base 7, and the coil of the head is connected to the printed wiring 8 on the mounting base 7 by a lead 19. In addition, in Figure 5,
10 is a mounting hole. Generally, there is not enough space around the head mechanically, so a small base 7 of about 5 x 10 mm 12 is used for mounting.

FIG. 6 is a longitudinal sectional view of the composite head 6. As shown in FIG.

The thin film recording/reproducing head section 6A is made by forming a lower core 6-2 by sputtering a magnetic material with a high saturation magnetic flux density, such as sendust, to a thickness of several micrometers on a ferrite substrate 6-1 with a polished end surface. , 8 on top of this lower core 6-2
After insulating with 102 or the like, 'al!' made of copper or the like is processed using processing techniques such as sputtering or vapor deposition and etching. A coil 6-3 is formed with 5 to 10 turns, and 8102 is sputtered thereon to a thickness of about 0.1 μm to 0.2 μm to form a recording/reproducing gap portion 6-4, and on top of that, the same material as the lower core is made. An upper core 6-5 is formed by sputtering, a protective layer 116-6 is formed on it, and a bonding glass 6-7 is formed on it.
The protective plates 6-8 are fused together using. In addition, the bulk erase head part 6 joins a magnetic core 6-9 made of sendust or the like and a magnetic core 6-11 made of the same material with a coil 6-10 wound in 10 to 20 turns.
An erase gap section 6-12 is formed therein.

The composite head 6 is constructed by integrating the thin film recording/reproducing head section 6A and the bulk erasing head section 6B. Note that it is desirable to sandwich a magnetic shield plate between both head portions 6A and 6B.

According to the composite head 6 having such a configuration, the protective plate 6-8 is connected from the recording/reproducing gap 6-4 in the thin film recording/reproducing head section 6A.
Since the thickness up to this side can be reduced to 30 μm or less, the distance between both gaps can be significantly reduced. Therefore, it is possible to make good contact between the recording/reproducing gap section 6-4 and the erasing gap section 6-12 at the same time. Furthermore, even when the recording/reproducing head section 6A is formed in two channels in the width direction of the track, the crosstalk during reproduction can be suppressed to about -40 (18) because the recording/reproducing head section 6A is formed of a thin film. Therefore, it is suitable for multi-head configuration and is easy to manufacture.

Furthermore, since the erase head section 6B is a normal bulk head, it can easily flow a large current and generate a large magnetic flux. Therefore, the luminance signal of about 7 MHI is -40 dB.
The following can be erased.

FIG. 7 is a block diagram showing the configuration of a control system that uses the composite head 6 to perform recording and erasing operations. One feature of this control system is that the PG pulse used for switching the recording head is also used for switching the erasing head. Terminal 1 shown on the left side of the diagram
1 is supplied with a video signal from an imaging device such as a solid-state imaging device, an external TV signal generator, or the like. This video signal is supplied to a vertical synchronization separation circuit 12 and an FM modulation circuit 13. From the video signal supplied to the vertical synchronization separation circuit 12, only the vertical synchronization signal S is separated and extracted, and this is supplied to the motor servo circuit 14. Motor servo circuit 1
4 is a rotational speed signal F from the disk drive motor 15.
Upon receiving the G pulse, the speed servo of the motor 15 is performed, and 3
Keep the rotation at a constant speed of 600RP~1. A magnetic disk 1 is attached to the shaft of the motor 15, which is detected by a PG coil 5 provided near the center of the disk 1, and 60 PG pulses are sent out per second. There is. After this pulse is waveform-shaped by the PG pulse detector 16, the motor servo circuit 14
and a recording/erasing control circuit 17, which will be described later.
supplied to The motor servo circuit 14 receives both the vertical synchronization signal and the PG pulse, and performs motor phase servo so that the leading edge VS1 of the PG pulse and the vertical synchronization signal maintains a time difference of 78 (63,5μ5×7).

On the other hand, the video signal supplied to the FM modulation circuit 13 is FM
After being modulated, the current is amplified by the recording amplifier 18, and the recording/reproducing gap R/W of the head 6 is output via the switch 19.20.
-1 and R/W-2 are supplied to excitation coils 21 and 22 corresponding to R/W-2.

On the other hand, the erase signal output from the erase signal generator 23 consisting of an oscillator is current-amplified by the erase amplifier 24 to become an erase current, which is then passed through the switches 25 and 26 to the erase gap E1. It is supplied to excitation coils 27 and 28 corresponding to E2.

Switches 19.20 and 25.26 are connected to the control circuit 1.
ON, OFF and switching are controlled by 7. When the control circuit 17 receives an operation command from an operation command switch 29 (release switch in the case of an electronic camera), it operates in synchronization with the PG pulse, and the switches 19 and 20 operate in synchronization with the PG pulse.
and 25°26 control.

FIG. 8 is a timing chart showing the operation of the control system shown in FIG. 7 above. As shown in FIG. 8, the vertical synchronization signal vS
is input every 1/60 seconds, and when the operation command switch 29 is turned ON at time t1 in a state where the PG pulse is input 7H ahead of the leading edge of the PG pulse, the P
At time t2 when the G pulse is input, a control signal is output from the control circuit 17, and the switch 25 is turned on by this output.
The switch 26 is controlled to be switched to the seventh illustrated state, that is, to the side a. Therefore, erasing using the erasing gap E1 becomes possible. In this example, erasing is performed using the erasing gap E1 while the disk 1 rotates twice. Then, at time t3, only the switch 26 switches to the b side. Therefore, erasing using the erasing gap E2 becomes possible as well. Note that at time t4, the operation command switch 29 is turned OFF, so that the above erasing operation is performed in one cycle (four revolutions of the disk).
This will end the process and move on to recording. That is, when the PG pulse is input at time t5, the erase operation is completed and at the same time one switch is turned on by the output from the control circuit 17.
Therefore, the switch 2o is controlled to be switched to the a side. Therefore, recording using the recording/reproducing gap R/W-1 is performed on the disk 1.
This is possible for a period of one revolution. At time t6 when the next PG pulse is subsequently input, the changeover switch 20 is switched to the b side. Therefore, recording using the recording/reproducing gap R/W-2 is also possible.

In this way, erasing and recording on two tracks is possible in six fields (1/10 seconds). And El and R/
Since W-1, E2 and R/W-2 are in the active state separated in time, crosstalk is less likely to occur. In addition to the recording/reproducing gaps R/W-1 and R/W-2, the erasing gap E1. Since E2 is also controlled to switch in synchronization with the PG pulse, so-called idle time does not occur at all.

Furthermore, since erasing is carried out over at least one revolution of the disk 1, no portion remains unerased. Note that by shifting the timing at which the operation command switch 29 is turned OFF, the erasing cycle can be performed over a period of two or more rotations.

Next, the main parts of the present invention will be explained with reference to FIGS. 9(a), (b), and (c) and FIG. 10. Figure 9(a)(b)(
c) is a diagram showing the head structure of the magnetic head device of the present invention. As shown in the figure, the composite head 6 is fixed to one end. On the base 7, two playback step-up transformers 31 and 32 are installed via an insulating layer (not shown) to enable two-channel playback. It is installed. Note that (a> is not shown in the figure, but the above transformers 31 and 32 have (
As shown in C), magnetic shielding cases 33 and 34 are used as covers.

According to the composite head device of this embodiment configured in this way, the distance from the head to the transformers 31 and 32 is the shortest, making it difficult to pick up noise and improving the S/N ratio. Furthermore, since the wiring resistance is minimized, frequency characteristics are also improved. Note that it is desirable that the magnetic permeability μ of the transformers 31 and 32 is high at high frequencies. In this example, μ at 10MHz
=500 is used. If μ is low, the number of turns on the secondary side of the transformers 31 and 32 must be increased, and the frequency characteristics will deteriorate.

FIG. 10 is a circuit diagram when the step-up transformers 31 and 32 are installed. 1st channel 40 and 2nd channel
Since the configuration is exactly the same as that of the channel 50, only the first channel 40 will be explained, and the second channel 50 will be explained.
The corresponding reference numbers in the 50s will be given and the explanation will be omitted.

First, during recording, the recording information applied to the terminal 41 is supplied to the recording amplifier 42, and the gate signal applied to the terminal 43 becomes H level, so that the recording transistor 44 is turned on. At this time, the gate signal of the reproduction transistor 45 is set to L level by the inverter 46, so that it is turned off. Therefore, the recorded information is stored in the coil 21 of the recording/reproducing head. The signal flows through transistor 44 and recording is performed. At this time, the primary coil of the reproducing step-up transformer 31 does not affect the recording operation.

On the other hand, during reproduction, the gate signal is at L level. Therefore, the recording transistor 44 is turned off.
The reproduction transistor 45 is turned on. Therefore, the reproduction information induced in the coil 21 of the recording/reproducing head is stepped up by the reproduction step-up transformer 31 and then outputted from the terminal 48 via the reproduction amplifier 47. At this time, since the output terminal of the recording amplifier 42 is short-circuited by the transistor 45, there is no possibility that the recording circuit will affect the above-mentioned reproduction operation. In FIG. 10, 49 is an erase signal supply terminal. Furthermore, if the entire circuit shown in Fig. 10 is made into a hybrid IC and this is mounted on the base 7,
The number of wiring lines is reduced, and S/N and frequency characteristics are further improved.

Therefore, FIGS. 11 to 15 show examples in which a hybrid IC is mounted on a base.

FIG. 11 is a diagram showing an equivalent circuit of noise in a head reproducing amplifier system including a step-up transformer. In FIG. 11, the symbol L'h is the inductance of the head H, Rh is the resistance of the head H, and Lp is the step-up [-primary of the lance T! , I! , Rp is the resistance of the primary winding of the step-up transformer T, 1s is the inductance of the secondary winding of the step-up 1 to lance T, and R8 is the resistance of the secondary winding of the step-up transformer T. Further, Eh is the head output voltage, Enh is the thermal noise of the Rh, Enp is the thermal noise of the Rp, EnS is the heat ms of the R8, Ena and Enb are the noise voltages of the differential input reproduction amplifier 60, and lna and lnb are the differential This is the sound current of the dynamic input reproducing amplifier 60.

In order to configure a head-reproducing amplifier system with a good S/N ratio, it is preferable to reduce each noise value and increase the winding ratio NS/Nl) of the step-up transformer T. Therefore, if the playback amplifier is set to a differential input, En will be 2 compared to a single input.
It becomes double, and in becomes 1/2. Moreover, the input capacitance (not shown) is also 17/2. Step-up ratio or turns ratio N
When S/Nρ is increased, the 1st division of ls and R5 becomes larger, and large noise is generated due to the flow of In. However, in the case of differential input, since In is reduced to 1/2, the above-mentioned influence is reduced. Further, since C1 is also reduced to 1/2, it is possible to increase the bandwidth. Therefore, we changed the regenerative amplifier to a differential input amplifier, and further changed its input elements and operating conditions to In with a small En.
FIG. 4 is a conceptual diagram of a structure using, for example, a transistor such that En and In are in a relationship that exhibits opposite characteristics. During recording, the recording/reproducing switch 61 is OFF and the recording/reproducing switch 62 is ON. Therefore, the recording signal is transmitted to the amplifier 63c and the diode 63 connected in antiparallel.
The recording/reproducing head R passes through the recording amplifier 63 consisting of a and 63b.
/w-1 is supplied to the coil 21. During reproduction, the recording/reproducing switch 61 is turned on and the recording/reproducing switch 62 is turned off.

Therefore, the reproduction voltage induced in the coil 21 is stepped up by the step-up transformer 31 and amplified by the differential input amplifier 60.

FIG. 13 is a diagram showing a specific circuit configuration of this embodiment. Reference numeral 70 in the figure is a recording/reproducing switch circuit provided with two sets of transistors corresponding to the previous recording/reproducing switches 61 and 62. The recording/reproducing switch circuit 70 is composed of four transistors 71.72.degree. 73.74 and an inverter 75. In the figure, 8a to 8u are terminals. Thus, when an H level signal is input from terminal 81 during recording, this H level signal is directly applied to the bases of transistors 72, 74, and is inverted in polarity by inverter 75 to become an L level signal. Given to the base of 73. Therefore, transistors 72.74 are turned on, and transistors 71.73
becomes OFF.

Further, during reproduction, when an L level signal is input from the terminal 81, the transistors 71.73 are turned on and the transistors 72.74 are turned off, contrary to the above case.

By the way, the portions surrounded by dotted lines in FIG. 13, namely the differential input amplifiers 60A and 60B and the recording amplifiers 63A and 6
3B and the recording/reproducing switch circuit 70 are hybridized and mounted on the head base.

FIG. 14 is a diagram showing the mounting state of the hybrid IC, and is a plan view showing the back side of the base 7. FIG.

The head chip 6 incorporates two recording/reproducing heads and two erasing heads. 8a to 8u are conductors such as copper! ! 1
! It is. The mark O marked on the conductor N111 indicates a through hole, which provides electrical continuity between the front side ring ff11g of the base 7 and the back side conductive film. Conductive films 8a, 8b, 8p
, 8G is the erase current input terminal, conductive 1118r, 8
u is a recording current input terminal, conductors 1118s and 8t are reproduction output terminals, and conductive film 81 is a recording/reproduction switching signal input terminal.

FIGS. 15(a) and 15(b) are diagrams similarly showing the mounting state of the hybrid IC, and are a plan view and a side view showing the front surface side of the base 7. In the figure, 31 and 32 are the step-up transformers already described, and each primary winding is connected to terminals 8f, 8fi and 8j, respectively.

81 and each secondary winding is connected to a respective conductive II 8c
, 8d, 8n, and 8o.

As explained in FIG. 11 above, if a material with high magnetic permeability is selected for the core material of the step-up transformer 31, 32, high inductance can be obtained with a small number of windings. The influence of ti sound 1: np, 1 ens can be reduced. For example, if the number of turns of the primary winding is 5 turns and the number of turns of the secondary winding is 25 turns, good results can be obtained. In addition, when using a single input, the input capacitance is 10 pF.
By changing the reproducing amplifier to a differential input type, the input capacitance becomes 5 pF. As a result, the inductance 3 seen from the secondary winding side of the step-up transformer 31.32
The resonance frequency of 5μH and input capacitance ff15pF is 12M1b
This becomes the limit value of the reproduction system frequency characteristics.

Fig. 16 is a diagram showing the frequency characteristics of the reproduction system, and Fig. 17 shows the frequency characteristics of the reproduction system.
The figure is a diagram showing the head equivalent total noise voltage.

In FIGS. 16 and 17, solid lines a and d represent a step-up transformer and a differential input regeneration amplifier in which the ratio of the number of turns of the primary winding to the secondary winding is 5 turns:25 turns as in this embodiment. Points 1b and e are for the case when the above step-up transformer and single-input regeneration amplifier are used, and dashed lines C and f are for the case when the above-mentioned step-up transformer and single-input regeneration amplifier are used. This is the case when using only As shown in FIG. 16, while a resonates at 12 MHz, b resonates at 8.5 MHz because it has no input capacitance reduction effect. Also C
is not stepped up, so the playback output is small. Further, as shown in FIG. 17, the noise voltage becomes the minimum at d near the resonance point of 12 MHz.

e has little difference from d at low frequencies, but 9M
Above Hz, the noise voltage increases extremely. Also, at low frequencies, it is about 10 (1B) compared to d.

The noise voltage becomes even higher near 12M City.

As described above, by using a differential input amplifier as a reproduction amplifier and providing a step-up transformer between it and the head, a reproduction system with a wide band and low noise can be realized. Furthermore, by converting the playback, recording amplifier, and recording/reproduction switch circuits into hybrid ICs and mounting them on the head base, it is possible to suppress as much as possible the deterioration of frequency characteristics due to increased noise, stray capacitance, and lead inductance. , it is also suitable for downsizing the device.

The present invention is not limited to the one embodiment described above, but can be implemented with various modifications as follows.

For example, as shown in FIGS. 18(a), (b), and (c), at least the recording/reproducing gaps R/W-1, R/
A disk contact surface 91 including W-2 and erasing gaps E1 and E2 has a flat surface in the track longitudinal direction indicated by arrow M, and a predetermined curvature, for example, 50 to 100 R, in the track width direction indicated by arrow N. It may be formed to have a curved surface. In other words, the entire head may have a kamabok shape. It has been experimentally confirmed that the composite head 90 having such a shape has better flat contact with the disk 1 than those having other shapes.

Further, the composite head may be constructed as shown in FIG. 19. What is shown in FIG. 19 is an example of a two-track composite head dedicated to data recording. This composite head is of the so-called tunnel erase head type, and the recording/reproducing gap R/W-1°R/W-2 is used as an override head gap. That is, the recording/playback gap R/
W-1 and R/W-2 have a width wider than the track width W1 (>60 μm), and this recording/reproducing gap R/W-1
, R/W-2 performs override recording. Two erasing gaps E1a, E1b and E2a, E2b per track are used to erase recording signals that protrude from the track width W1. Thus, during playback, the head width is wider than the track width W1, making playback tracking easier, but the head has two erase gaps E1b and Ela within the guard band width W2 (40 μm) as shown in the figure. There is a problem in that the head is difficult to manufacture because it has to be formed.

Also, as shown in FIG. 20, a part of the erase side changeover switch 26 shown in FIG. 7 is turned on instead.

An OFF switch 100 may be provided so that erasing operations can be performed simultaneously on the erasing gaps E1 and E2.

FIG. 21 is a diagram showing the timing of FIG. 20. As shown in FIG. 21, erasing gaps E1 and E2 enable erasing at the same time. Therefore, according to this example, the erasing/recording cycle can be made shorter than that of the one shown in FIG. 7, and erasing and recording can be performed at 15 revolutions per second.

Further, as shown in FIGS. 22 and 23, the recording/playback side changeover switch 20 and the erasing side changeover switch 2 shown in FIG.
6 may be switched to -1'#J at the same time. However, in the case of FIG. 23, the switching directions of the recording/reproducing side changeover switch 20 and the erasing side changeover switch 26 are reversed by the inverter 110.

FIG. 24 is a diagram showing the operation timing of FIGS. 22 and 23. As shown in FIG. 24, recording by R/W-1 and erasing by El or E2 (broken 1) can be active during the same period. Also, recording by R/W-2 and erasure by E2 or El (break I) can be active during the same period.R/W-1 and El, and R/W-2 and E2 can be active at the same time. If
The erasing and recording periods completely overlap on the same track, but as described above, the erasing gap E1. E2 and the recording/reproducing gaps R/W-1 and R/W-2 are provided apart by a predetermined distance X, and there is no problem because the erasing operation is performed first. In other words, recording is performed immediately after erasing. Thus, in frame recording, 3
0 times/second.

In field recording, it is possible to erase and record 60 times/second, which is even faster than in the case of Figures 20 and 21.
Recording cycle becomes shorter. In this example, crosstalk between the erasing head section and the recording/reproducing head section tends to occur to some extent, so it is desirable to use the circuit for image recording or digital data recording using a modulation method that is resistant to noise. In data recording, it is a great advantage that data recording can be performed on two tracks without head access dead time. In the case shown in FIG. 23, that is, the erase gap E1. If the active period of E2 is set to the timing shown by the broken line in FIG. 24, recording and erasing are performed at the same timing on adjacent tracks. Therefore, compared to the case of FIG. 22, the occurrence of crosstalk is relatively small.

It goes without saying that various modifications can be made in addition to the above without departing from the gist of the present invention.

〔Effect of the invention〕

In the magnetic head device of the present invention, a head chip is mounted on a base, and the head chip is switched to a recording system or a reproducing system by a recording/reproducing switching circuit, and the recording/reproducing switching circuit switches the head chip to the recording system. a recording current is amplified and supplied to the head chip by a recording amplifier, and
With the head chip connected to the playback system by the recording/reproduction switch circuit, the level of the signal picked up by the head chip is boosted by a step-up lance attached to the base, and the boosted signal is generated. is amplified by a differential input regenerative amplifier. The present invention is characterized in that the previous recording/re-switching switch circuit, the recording amplifier, and the differential input amplifier are made into a hybrid IC and mounted on the base.

Therefore, according to the present invention, even if the spacing loss is not sufficiently good and the spacing loss is relatively large, it is possible to obtain a large reproduction output with good S/N and frequency characteristics. In addition to being able to record and reproduce various types of information such as image information well, and also to enable immediate re-recording, a particularly wide-band and low-noise reproduction system (q
Therefore, it is possible to provide a small and easy-to-manufacture magnetic head device that can suppress deterioration of frequency characteristics due to increases in jump noise, stray capacitance, lead inductance, and the like.

[Brief explanation of drawings]

1 to 8 are diagrams showing the configuration of basic parts other than the main parts in an embodiment of the present invention. 4 and 4 are schematic diagrams and head structure diagrams showing another example of the head configuration corresponding to FIGS. 1 and 2, and FIGS. 5 and 6 are a plan view of the composite head device and a diagram of the composite head. 7 is a block diagram showing the configuration of a control system that causes the composite head to perform recording and erasing operations (V). FIG. 8 is a diagram showing the operation timing of each part of the control system shown in FIG. Yes. Figures 9 (a>(b) (C) and 10
The figure shows the configuration of the main part of the same embodiment;
)(b)(c) are diagrams showing the configuration of the composite head device, the first
FIG. 0 is a circuit diagram when the composite head device shown in FIG. 9 is used. 11 to 17 are diagrams showing other embodiments of the present invention. FIG. 11 is a diagram showing a circuit of the reproduction amplifier system, FIG. 12 is a conceptual diagram of the same embodiment, and FIG. Circuit diagrams showing the specific configuration of the same embodiment, FIGS. 14 and 15 (
a>(b) is a diagram showing the actual device state of the hybrid IC,
FIG. 16 is a diagram showing the frequency characteristics of the reproduction system, and FIG. 17 is a diagram showing the total head noise voltage. Figures 18 (a), (b), and (C) are diagrams showing modifications of the surface shape of the composite head, Figure 19 is a diagram showing an application example of the composite head, and Figure 20 is a partial modification of Figure 7. 21 is a diagram showing the operation timing of FIG. 20, and FIGS. 22 and 23 are partial configuration diagrams showing an example in which a part of FIG. 7 is modified. FIG. 24 is a diagram showing the operation timing of FIGS. 22 and 23. 1... Rotating magnetic disk, 2... Composite head, 4...
...PG yoke (rotational position detection index), 5...PG
Coil (pulse detection means), 6... Composite head, 6A
... Thin film recording/reproducing head section, 6B... Bulk erasing head section, 7... Head mounting on base, 8... Printed wiring, 21.22 and 27.28... Excitation coil, 2
- Release switch (operation command switch), 31
゜32...Step-up transformer for reproduction, 33゜3
4... Magnetic shield case, 40, 50... 1st ° 2nd channel, 60... Differential input regeneration amplifier, 63
. . . Recording amplifier, 70 . . . Recording/reproduction switching circuit, Tl, T2 . . . Track, R, 'W-1. R/W-
2...Recording/reproduction gap, El, E2...Erasing gap. Applicant's representative Patent attorney Atsushi Tsuboi Figure 1 ii

Claims (3)

[Claims] (1) A base, a head chip mounted on the base, a recording/playback switch circuit that switches this head chip between the recording system or the playback system, and the head chip connected to the recording system by this recording/playback switch circuit. a recording amplifier that amplifies and supplies a recording current to the head chip in a state in which the head chip is connected to a reproduction system by a recording/reproduction switch circuit; and a level of a signal picked up by the head chip in a state in which the head chip is connected to a reproduction system by and a differential input regenerative amplifier that amplifies the signal boosted by the step-up transformer.
A magnetic head device characterized in that a pre-recording/re-switching switch circuit, a recording amplifier, and a differential input amplifier are formed into a hybrid IC and mounted on the base. (2) The head chip is a composite magnetic head formed by bonding a plurality of thin film heads such that each head gap is lined up at a predetermined interval in the track width direction. magnetic head device. (3) The magnetic head device according to claim (1), wherein the step-up transformer includes a shield case.