JPH04276308A - Device for supporting magnetic head - Google Patents

Abstract

PURPOSE:To prevent the deterioration of video signals, sound signals, etc., due to azimuth loss by making the azimuth angle of a helical track on a magnetic tape and the azimuth angle of a magnetic head coincide. CONSTITUTION:A head base is comprised of an elastically deformable metal plate 103, a magnetic head chip 101 is stuck on to one end of the metal plate 103, the other end of the plate is fixed on a revolving drum, and further, on both surface and back faces of the metal plate 103, a plural number of electrostrictive element 104 and electrode 105 are attached respectively. By applying a voltage via an electrically conductive line 106 from a control/driving circuit, the electrostrictive element 104 is distorted, the metal plate 103 is deformed, the magnetic head chip 101 is caused to revolve, and the azimuth angle of a head gap is made to coincide with the azimuth angle of the helical track of the magnetic tape.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a support device for a magnetic head in a rotating drum device for helically recording video signals, audio signals, etc. on a magnetic tape in devices such as video tape recorders and audio tape recorders. .

0002

2. Description of the Related Art FIG. 4(a) is a perspective view of a rotating drum that is part of a drum assembly of a conventional structure used in a VTR or the like for recording video signals, audio signals, etc. helically on a magnetic tape. (b) is a sectional view taken along line B-B in figure (a), Figure 5 (a) is a perspective view of the head chip attached to the head fixing base, and Figure 5 (b) is a cross-sectional view of figure (a). It is a front view as seen from arrow C.

The prior art will be explained using FIGS. 4 and 5. In the figure, this conventional example has a magnetic head chip 201,
It has a head base 202, a rotating drum 203, a rotating drum center 204, a screw hole (A) 205, a head base fixing screw 206, a screw hole (B) 207, and a set screw 208, and 209 is a magnetic head chip. gap,
θ indicates the azimuth angle of the head gap.

The magnetic head chip 201 is fixed with an adhesive to a head base 202 made of brass or ceramic, and the head base 202 is further screwed to a rotating drum 203 made of aluminum with a head base fixing screw 206. It is fixed in place. Also, the screw hole (B) 207 is connected to the rotating drum center 204 and the screw hole (A) 2.
Head base 202 is located on the extension of the line connecting 05.
It is provided in such a structure that it penetrates from the surface opposite to the mounting surface. The head base 2 is inserted into the screw hole (B) 207.
02 to adjust the installation height of the magnetic head chip 201.

The rotating drum 203 to which the magnetic head is attached in the above-described structure is further combined with a fixed drum (not shown) and incorporated into a VTR device, etc., so that the magnetic head chip 201 tracks a helical-shaped track on a magnetic tape when the device is in operation. Record video signals, audio signals, etc., or reproduce recorded video signals, audio signals, etc.

[0006]

[Problem to be solved by the invention] In general, devices such as VTRs have the ability to self-record (record) and playback.
A function is required to reproduce video signals, audio signals, etc. recorded on magnetic tape by other devices without deteriorating image quality, sound quality, etc. However, with conventional devices such as VTRs that use the above-mentioned rotating drum assembly, when playing back magnetic tapes recorded on other devices, the deterioration falls within an acceptable range and video signals, audio signals, etc. cannot be played back. There was a problem.

[0007] In order to reproduce video signals, audio signals, etc. recorded on a magnetic tape by other devices without deteriorating image quality, sound quality, etc., a magnetic head chip must satisfy the following two conditions as is well known. .

(1) The magnetic head chip must be mounted on the rotating drum with sufficient dimensional accuracy.

(2) The azimuth angle of the magnetic head must match the azimuth angle of the helical track of the magnetic tape.

Processing of rotating drums currently in practical use
In terms of assembly technology, when the above-described conventional structure is employed, the dimensional accuracy of attaching the magnetic head chip to the rotating drum is ±2 microns, and the angular dimensional accuracy of the azimuth angle is ±1 to 2 degrees. Generally, the width of the helical track in VTR equipment is 20 mm.
Based on the above dimensional accuracy, it is believed that the dimensional accuracy of the magnetic head chip installation is the main cause of deterioration in image quality, sound quality, etc. when playing back magnetic tapes recorded with other devices. I can't think of it. On the other hand, the azimuth angle of the magnetic head is approximately ±6 degrees, and due to the dimensional accuracy of the azimuth angle, when playing back a magnetic tape recorded with another device, azimuth loss due to the dimensional accuracy of the azimuth angle is reduced. It can be easily inferred that this is the main cause of deterioration in image and sound quality.

[0011] An object of the present invention is to
It eliminates the problems of devices such as R, and does not cause deterioration of video signals, audio signals, etc. when playing back magnetic tapes recorded with other devices, that is, video signals caused by azimuth loss.
It is an object of the present invention to provide a magnetic head support device that provides a rotating drum assembly that does not cause deterioration of audio signals or the like.

0012

[Means for Solving the Problems] A magnetic head support device of the present invention includes a metal plate having a substantially rectangular hole in the center and elastically deformable, and a magnetic head chip attached to one end of the metal plate. a fixing member attached to the other end of the metal plate and fixed to the rotating drum via the head base; a plurality of electrostrictive elements fixed to the front and back surfaces of the metal plate;
The electrostrictive element includes a plurality of electrodes formed on the surface thereof, a preamplifier, a control circuit, and a drive circuit, and a coil wound around the head chip and the drive circuit are connected to the preamplifier and the control circuit. Connect with signal line through
The drive circuit and the electrode are connected by a drive line, and the preamplifier amplifies the reproduction signal of the signal recorded on the magnetic tape by the magnetic head chip, and the control circuit amplifies the amplified reproduction signal. outputting a control signal for controlling the deformation of the metal plate so that the reproduction signal output of the magnetic head chip is always maximized by comparing with the immediately preceding reproduction signal, and based on this control signal from the control circuit; The electrostrictive device is characterized in that it operates to apply a voltage to the electrostrictive element via the electrode.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing the entire structure of a magnetic head support device according to an embodiment of the present invention, and FIGS. 2(a) and 2(b) show a structure in which a head chip, which is the main part of this embodiment, is attached to one end. FIG. 3 is a perspective view and a cross-sectional view taken along the line A--A of the head base portion. FIG. 3 is a perspective view illustrating torsional deformation that occurs in the head base when voltage is applied to the electrostrictive element from the control/drive circuit of this embodiment.

This embodiment includes a metal plate 103 with a head chip 101 attached to its tip, a plurality of electrostrictive elements 104 attached to this metal plate 103, an electrode 105 for applying voltage to the electrostrictive elements 104, and an electrode. The conductive wire (A
) 106, conductive wire (B) 107 connected to the metal plate 103
, a mounting hole 108 for fixing the metal plate 103 to the rotating drum, a fixing member 109 for attaching the metal plate 103 to the rotating drum, a control circuit 110 for controlling the voltage applied to the electrode 105 of the electrostrictive element 104, and the electrode 105. A drive circuit 111 that applies voltage to the magnetic head chip 101, a preamplifier 112 that amplifies the weak reproduction electric signal of the magnetic head chip 101, and a signal line that connects the magnetic head chip 101 and the preamplifier 112 (
A) 113, a signal line (B) 114 that sends the reproduction signal of the head chip from the preamplifier 112 to the control circuit 110, a signal line (C) that connects the control circuit 110 and the drive circuit 111
115.

This embodiment will be explained in detail below with reference to FIGS. 1 to 3. First, Fig. 2(a) and A in Fig. 2(a)
The configuration of the head base portion will be explained using FIG. A rectangular hole is provided in the center of the elastically deformable metal plate 103, and electrostrictive elements 104a, 104b, 104c, and 104d are provided on the front and back surfaces as shown in FIG.
As shown in (b), they are fixed with adhesive, and a conductive wire (B) 107 is connected to a part of the metal plate 103 to constitute one electrode of the electrostrictive element 104. Electrodes 105a, 105b, 105c, and 105d are provided on the surface of each electrostrictive element 104 that does not face the metal plate, and conductive wires (A) 106 are provided on these electrodes 105.
a, 106b, 106c, and 106d are connected. A magnetic head chip 101 is adhesively fixed to the tip of the metal plate 103, and a fixing member 109 having a mounting hole 108 in the center thereof is attached to the rear end. The member of FIG. 2(a) configured in this way is similar to the head base 202 of the conventional example.
Similarly, it is fixed to the rotating drum using the mounting hole 108 with screws, and is further incorporated into a device such as a VTR.

FIG. 3 is a diagram illustrating how the azimuth angle of the gap of the magnetic head chip 101 changes relative to the azimuth angle of the helical track of the magnetic tape when a voltage is applied to the electrostrictive element 104. As shown in Figure 3, conductive wires (A) 106a and 106d are connected
When a negative (-) voltage is applied to the conductive wires (A) 106b and 106c, the electrostrictive elements 104a and 104d expand, and the electrostrictive elements 104b and 104c contract. Therefore, the portion of the metal plate 103 sandwiched between the electrostrictive elements 105a and 105b is warped downward. On the other hand, the electrostrictive elements 105b and 1
The part sandwiched between 05c is curved upward. As a result, the magnetic head chip 101 rotates clockwise compared to when no voltage is applied to the electrostrictive element 104. That is, the angle formed by the azimuth angle of the helical track of the magnetic tape and the azimuth angle of the gap between the magnetic head chips 101, that is, the amount of deviation between the two azimuth angles changes. Similarly, conductive wire (A) 10
Apply negative (-) voltage to 6a and 106d, and connect the conductive wire (A
) When a positive (+) voltage is applied to 106b and 106c, the magnetic head chip 101 rotates counterclockwise, and the amount of deviation between the azimuth angle of the helical track of the magnetic tape and the azimuth angle of the magnetic head changes.

Next, the overall structure and dynamic principle of the magnetic head support device of this embodiment will be explained using FIG.

First, the overall structure of the magnetic head support device will be explained. A wire is wound around the magnetic head chip 101 to enable magnetic-electrical conversion (hereinafter referred to as a coil, not shown), and both ends of this coil are connected to a signal line (A).
It is connected to the preamplifier 112 via 113. The preamplifier 112 has a signal line (B) 114 and a control circuit 110.
, are connected to the drive circuit 111 via a signal line (C) 115. Conductive wires (A) from electrodes 105a and 105d
106a, 106d are combined into one conductive wire, and conductive wire (A) 106b, 1 from electrodes 105b, 105c
06c are also combined into one conductive wire and each drive circuit 1
11. Furthermore, a conductive wire (B) 107 from the metal plate 103 is also connected to the drive device 111.

Next, the principle of operation will be explained. A weak reproduction signal of the helical track of the magnetic tape by the magnetic head chip 101 is sent to the preamplifier 112 via a signal line (A) 113. The weak signal is 1 in the preamplifier 112.
The signal is amplified by approximately 000 times and sent to the control circuit 110 via the signal line (B) 114. The control circuit 110 performs the following operations.

(1) First, a control signal for rotating the magnetic head chip 101 clockwise and counterclockwise is output.
In parallel with this, reproduction signals generated when the magnetic head chip 101 rotates clockwise and counterclockwise are captured, and the magnitudes of these two signals are compared. Based on this comparison, the direction of the signal that controls the voltage applied to the electrostrictive element 104 is determined.

(2) Next, the control signal is slightly changed, and the reproduction signal sent at this time is compared in magnitude with the immediately preceding reproduction signal.

(3) In the comparison of (2), if the reproduced signal is larger than the immediately preceding reproduced signal, the operation (2) is repeated until the magnitude of the transmitted reproduced signal becomes smaller than the immediately preceding reproduced signal. It will be done.

The drive circuit 111 that receives the control signal via the signal line (C) 115 operates the electrostrictive element 1 based on the control signal.
04 is output between the metal plate 103 and the electrode 105 via conductive wires (A) 106 and (B) 107 to deform the metal plate 103 and move the magnetic head chip 101 clockwise or counterclockwise. Rotate it.

Since the magnetic head support device of this embodiment operates as described above, the azimuth angle of the magnetic head can be made to match the azimuth angle of the helical track of the magnetic tape.

[0026]

[Effects of the Invention] As explained above, the present invention comprises a head base made of an elastically deformable metal plate, a head chip attached to one end of this metal plate with adhesive, and the other end fixed to a rotating drum. Furthermore, a plurality of electrostrictive elements are pasted on both the front and back sides of the metal plate, and a control/drive circuit is applied to the electrostrictive elements so that the azimuth angle of the head gap matches the azimuth angle of the helical track of the magnetic tape. By applying a voltage that causes deformation to the plate,
The azimuth angle of the magnetic head can be made to match the azimuth angle of a helical track of a magnetic tape recorded by another device such as a VTR. Therefore, deterioration of video signals, audio signals, etc. due to azimuth loss can be prevented, and deterioration of image quality, sound quality, etc. can be kept within an acceptable range.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of a magnetic head support device according to an embodiment of the present invention.

FIG. 2 shows a head base portion with a head chip attached to one end, which is a main part of this embodiment, and FIG. 2(a) is a perspective view;
Figure (b) is a sectional view taken along line A--A in figure (a).

FIG. 3 is a perspective view illustrating torsional deformation occurring in the head base portion in this embodiment.

FIG. 4 shows a rotating drum that is a part of a conventional drum assembly; FIG. 4(a) is a perspective view, and FIG.
) is a sectional view taken along line BB.

5 shows a state in which the head chip is attached to the head fixing base, FIG. 5(a) is a perspective view, and FIG. 5(b) is a front view taken in the direction of arrow C in FIG. 5(a).

[Explanation of symbols]

101, 201 magnetic head chip 103
Metal plate 104 Electrostrictive element 105 Electrode 106 Conductive wire (A) 107 Conductive wire (B) 108 Mounting hole 109 Fixing member 110 Control circuit 111 Drive circuit 112 Preamplifier 113 Signal line (A) 114 Signal line (B) 115 Signal line ( C) 202 Head base 203 Rotating drum 204 Rotating drum center 205 Screw hole (A) 206 Head base fixing screw 207 Screw hole (B) 208 Potato screw 209 Head gap

Claims (2)

[Claims] 1. An elastically deformable metal plate having a substantially rectangular hole in the center, a magnetic head chip attached to one end of the metal plate, and a head base attached to the other end of the metal plate. a fixing member fixed to the rotating drum via the metal plate, a plurality of electrostrictive elements fixed to the front and back surfaces of the metal plate, a plurality of electrodes formed on the surfaces of the electrostrictive elements, and a preamplifier. , comprising a control circuit and a drive circuit, a coil wound around the head chip and the drive circuit are connected by a signal line via the preamplifier and the control circuit, and the drive circuit and the electrode are driven. A magnetic head support device characterized by being connected by a wire. 2. A reproduction signal of the signal recorded on the magnetic tape by the magnetic head chip is amplified by the preamplifier, and the amplified reproduction signal is compared with the immediately preceding reproduction signal by the control circuit, so that the reproduction signal of the signal recorded on the magnetic tape by the magnetic head chip is constantly outputting a control signal for controlling the deformation of the metal plate so that the reproduction signal output is maximized, and applying a voltage to the electrostrictive element via the electrode based on this control signal from the control circuit. 2. The magnetic head support device according to claim 1, wherein the magnetic head support device operates to perform the following operations.