JPS6057521A - Azimuth adjusting device of rotary head - Google Patents

Abstract

PURPOSE:To adjust the angle of a head easily even after fitting by impressing an adjusting voltage to a piezoelectric element member for head angle adjustment which is interposed between a head rotating member and the head. CONSTITUTION:The piezoelectric element members A1 and A2 are fitted to an upper cylinder 2 through a fitting base 9, and a head base is stuck onto the base. Voltages having magnetic polarities opposite to each other are impressed to the elements A1 and A2 by conductors 11a and 11b to make the expansive displacement directions of the elements A1 and A2 opposite to each other. In case of setting of an azimuth, for example, at a recording time, an adjusting signal is reproduced from a standard tape having a correct head angle, and a voltage adjuster 14 is so adjusted that the reproducing level of a servo circuit 15 is maximum, and the elements A1 and A2 are displaced in directions opposite to each other in the thickness direction to adjust the head angle to a correct angle. This adjusting position is stored, and the head is set to this adjusting position at a recording operation time thereafter, and a required adjusting voltage is impressed to the piezoelectric element members A1 and A2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an azimuth adjustment device for a rotary head in a VTR (video tape recorder).

As is well known, in a VTR, if there is a difference between the inclination angle of the head gap with respect to the tape during recording and the inclination angle of the head gap during playback, a so-called azimuth loss occurs in which the playback output decreases.

This loss is related to the wavelength of the signal, and increases as the wavelength becomes shorter. For this reason, this azimuth loss appears significantly in short wavelength signals such as VTR signals.

Incidentally, in recent years, VTRs are aiming at longer recording/reproducing times and higher recording density per unit volume, so the width of the recording band (track) tends to be narrower than before. Due to this, the accuracy of track bending due to the lead surface of the rotary head cylinder, the rotational locus error of the head, etc. are becoming more likely to affect the reduction in reproduction output. For this reason, in such a VTR, it is necessary to adjust the head angle to an accurate angle with higher precision and to minimize the azimuth loss that significantly affects the reduction in reproduction output.

Nowadays, the azimuth Ml'l adjustment means of the rotary head in the conventional VTR is replaced by an upper cylinder rotary type VTR.
will be explained using FIG. 1 as an example. Code in the figure (1)
The lower cylinder (2) is an upper cylinder, and the lower cylinder (1) is connected to a VTR (not shown) via appropriate members.
It is fixed on the main body side. A rotary shaft (4) is rotatably supported on the lower cylinder (1) via bearings (3a) (3a). The upper cylinder (2) is attached to this rotating shaft via a disk (5), and is configured as an upper cylinder rotating type. M is rotation [
In the dynamic DD motor, T is a rotary transformer.

Head (hesotochiso 7') Hi navel)' He-, ((6
1K is fixed, and the head base (6) is fixed at a predetermined position on the lower surface of the upper cylinder (2) with screws (7). In this mounting manner, the head H faces the slit between the two cylinders (1) +2). (8)
is a front screw, which is provided to adjust the head height. Tighten or untighten it to adjust the head base (
6) The head height is adjusted by stirring 3 and the azimuth W4 of the head.
This machining accuracy allowed the required head angle to be obtained after installation.

However, with such conventional azimuth adjustment means for a rotating head, the required head angle is obtained by adjusting the angle before installation, and the installation to the upper cylinder (2) etc. after processing is difficult. Errors and the influence caused by stirring on the tilt of the hendogyasop when adjusting the rad height according to Sesoto Sukuguu (8) were almost ignored.For this reason, it is extremely difficult to hold the head angle to the required angle. There was a problem.

Incidentally, in audio heads, there is a known azimuth adjustment method that uses the elasticity of a coil spring.
It is extremely difficult to make adjustments on the μm order required for VTRs using the same means, and VTRs require a small space for the head mounting section and use a rotating head system, and furthermore, r+':r Since this is a reciprocal recording system, such an azimuth adjustment means for the audio head could not be adopted.

This invention was developed by focusing on such conventional problems, and by using a piezoelectric element member, f+i'i
It is an object of the present invention to provide an azimuth adjustment device for a rotary head that can accurately adjust the head angle even after installation.

The present invention will be explained below based on the drawings. Figures 2 to 5
The figure shows a first embodiment of the invention. Furthermore, the second
In each of the following figures, the same or equivalent members as those in FIG.

First, to explain the configuration, in the invention of , the lower surface side of the upper cylinder (rotating cylinder) + 2 (Figure 2 and the following figures are for the sake of clarity, so that the upper and lower 1B5.1 sections are the same as in Figure 1 above). is reversed) in place with the mounting pace (
9) Piezoelectric element members A, A for head angle adjustment via
2 is attached, and a head base (6) is fixed onto the piezoelectric element members A and A2. Piezoelectric element member A1Δ
2 is made of a piezoelectric material such as piezoelectric ceramic, and in this embodiment, the 4'P is made of a piezoelectric material such as piezoelectric ceramic.
As shown in FIG. 4, two piezoelectric element members A2 are disposed on the left and right sides of the head 11. A displacement voltage application conductor KM (lla) (1111) is connected to the back sides of both piezoelectric element members A and A2 in the following connection manner. That is, the back surface 1 of one piezoelectric element member A1 [(q upper surface and the lower surface on the back side of the other piezoelectric element member A2 are both connected); The upper surface of the back side of the other piezoelectric element part IA2 is commonly connected, and a conductor (lla) (1111) is connected from the common connection point of both of them.
are shown, respectively. 17 and both piezoelectric elements
Voltages of opposite polarity are applied to child members A and A2,
The expansion displacement directions of both piezoelectric element members A and A2 are opposite to each other, and the head! ■ Tilt i + JJ chapter is made.

(1 is the head coil conductor, (+31 is the printed circuit board for relay.) Next, the above pressure 'f [element member A, A2
The adjustment heavy pressure supply circuit for applying the adjustment pressure 'Id' will be explained with reference to FIG. The symbol E in the figure is a constant voltage power supply,
The output line of the voltage regulator Oa is exclusively connected to the voltage regulator θ◇, and the output line of the voltage regulator Oa is connected to the piezoelectric element members A and A2 via a brush feeder (not shown) through means.

+, H pressure regulator (1) is a device that precisely varies the constant voltage from the constant voltage power source E to adjust and set the voltage applied to the piezoelectric element members A and A2 to the required value, and is a variable voltage regulator like a volume control. Means is also provided for this voltage λ!11 rectifier (1
4) also has a function of adding the output voltage from the atmosphere correction circuit, etc., which will be described later, to the above set voltage, and furthermore, if the piezoelectric element members A and A2 have hysteresis in electro-mechanical displacement, the applied voltage is It also has a jA ffl that adjusts the appropriate AC signal and corrects its hysteresis.

(One is a servo circuit, which is used to apply servo to the azimuth (angle L+Z) error so that it is minimized during playback mode.Azimuth loss is used as a signal for azimuth error detection. 4. Since high frequency signals that are susceptible to # are used, an IIPF is built in to extract them.

(Iω is an atmosphere correction circuit, which is used to correct displacement errors caused by changes in the atmosphere such as the temperature of the piezoelectric element members A and A2, and is composed of a circuit equipped with a temperature detection element such as a thermistor, for example. 0η is a special recording/reproducing pattern generator, which is used to send to the voltage regulator (14) a voltage that causes the head H to produce a displacement corresponding to the special mode during special recording and special reproduction. y
/c is an image processing circuit.

Next, the head angle (azimuth) setting operation and effect will be explained.

■ In recording mode.

Use the mark 1IllB tape with the correct head angle trl, play the angle (azimuth) adjustment signal,
Servo circuit (voltage 1.j so that the reproduction level of the high frequency region extracted by one is the maximum (minimum azimuth error)
]Adjust the differential gain 4), and as shown in Figure 4, adjust the displacement amounts of both piezoelectric element members A and A2 in the IV direction in opposite directions so that the head angle becomes the correct angle. . Then, the adjustment position is memorized and set at this adjustment position during subsequent recording operations, and a required adjustment voltage is applied to the piezoelectric element members A and A2. Note that in this recording mode, unlike in the playback mode described below, the signal from the servo circuit +151 does not become a feed signal to the voltage regulator 04), but becomes an oven loop. There is.

■ In playback mode.

The setting operation for the voltage difference (14) is the same as in the recording mode.In this playback mode, the servo circuit a functions during subsequent tape playback, and the azimuth error is always maintained during the jjb operation. The servo is applied so that the minimum distance is reached.Incidentally, there are two ways to apply this servo: ■@, either of which can be applied. ■Azimuth errors are continuously detected during playback operation. How to apply the towing servo after the
There are two methods: detecting the optimum azimuth by reproducing the same track several times (steal operation) 1-, and subsequently sending out the correction voltage at that time to the voltage regulator Oa.

During both recording and re-operation, the displacement error of the piezoelectric element member AI A2 due to atmospheric salinity, etc. is corrected by adding the correction voltage from the atmosphere correction circuit (1G) to the adjustment setting voltage. It is corrected to At the time of special recording or special reproduction, the voltage for displacement corresponding to the special mode is further added to perform the desired ii+, b operation.

By the way, when a rotating cylinder has multiple head/nods (I:tl), set the adjustment setting voltage for each head/nod, memorize it, and use it for each side during subsequent operation. Apply the adjustment setting voltage corresponding to the head and throat.

Next, FIG. 6 or a second embodiment of the present invention is shown.

This embodiment is similar to the mounting base (9) in the first embodiment.
) is omitted, and both piezoelectric element members A and A2 are directly fixed to the anopone ring (2).

The head angle setting operation and operation are similar to those of the first embodiment. According to this embodiment, the overall height dimension can be reduced, making it suitable for the small space required for the head mounting portion of a VTR.

FIG. 7 shows a third embodiment of the invention. In this embodiment, the head base (6) in the first embodiment is omitted, and the head (2) is directly fixed onto both piezoelectric element members A and A2. Piezoelectric element member A.

Comparing the dimensions and shape of A2 with those of each of the above examples, 3
Although it is necessary to process the L to be more compact, it is possible to further reduce the size of the entire head portion.

FIG. 8 shows a fourth embodiment of the invention. This actual Mi example has a configuration similar to that of the second embodiment (Fig. 6), but the piezoelectric element member A3 is one piece on one side only, and the other side has a fixed piece (+19 and To explain the tilting operation, in this embodiment, one piezoelectric element member A3
The azimuth adjustment of J: Rehenode 11 is made to the expansion/contraction displacement of .

FIG. 9 shows an example of the fifth embodiment of this invention. In this embodiment, the head II is of a so-called cantilever type, and two piezoelectric element members A4 and A5 are arranged in a sandwich shape with a piezoelectric element mounting plate in between.

Both piezoelectric element members A4 and A5 are piezoelectric element mounting plates (1!9
The surfaces that are not in contact with each other are commonly connected, and one conductive wire (lla) is led out from this common connection point. The other conductor (11
1)) is when an adjustment voltage is applied in parallel to both piezoelectric element members A4A3 through the piezoelectric element mounting plate (connected to one, conductive wire (1'1aX11+)) which serves as the electric A÷V plate. The piezoelectric element member A4A3 extends t1 in the left-right direction in the figure.
(heads whose displacements are opposite to each other) i is adjusted in angle.

FIG. 10 shows a sixth embodiment of the invention. This embodiment is based on almost the same principle as the fourth embodiment (FIG. 8), with only one piezoelectric element member A3 on one side, and the other side of the plate-shaped helad base (6) facing the top surface. Specified piece (21
It is fixed at

FIG. 11 shows a seventh embodiment of the invention. In this embodiment, a piezoelectric element assembly for head height adjustment is disposed in the lower stage of the first embodiment (FIG. 3, etc.), and the azimuth N"J
It has a double adjustment of the M means and the height spJ adjusting means. The piezoelectric element assembly for head height adjustment has two piezoelectric element members A and A7 attached in a sandwich shape to a piezoelectric element base plate C21) for height displacement]
Toso has been completed.

In each of the embodiments of the lte, a case has been described in which a piezoelectric element member, etc. is attached to the upper cylinder, which is a rotating cylinder, but the present invention is not limited to such a cylinder indicator type, but can be applied to both the upper and lower cylinders. It can also be used in systems where the head is fixed and the head is attached to a rotating disk or the like and rotates.

As described in detail above, according to the present invention, a piezoelectric element member that utilizes a head angle of 1iIY is interposed between the head rotating member and the head, and the adjustment voltage corresponding to the required angle division Ii is applied to this piezoelectric element member. Since the head angle is often determined only by the machining accuracy of the head tip before installation, it is possible to increase the head angle to the correct angle even if there are errors during installation. The effect of being able to adjust and set accurately can be obtained. Therefore, it is possible to improve the processing yield of head chips, and it is possible to achieve the effect of reducing the cost of components, such as VTRs (4 devices).

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional side view of a rotary head azimuth adjustment device in a conventional VTR, and FIGS.
Figure 2 shows a perspective view of the head mounting part, Figure 3 is a cross-sectional view taken along the line ■-■ in Figure 2, Figure 4 is a front view of Figure 2, and Figure 5 shows the adjustment. A block diagram showing an example of a voltage supply circuit, FIG. 6 is a front view of a head mounting portion in a second embodiment of the present invention, and FIG. 7 is a front view of a head mounting portion in a third embodiment of the present invention. 8 is a front view of the head mounting portion in the fourth embodiment of the present invention, FIG. 9 is a front view of the head mounting portion in the fifth embodiment of the present invention, and FIG.
0 is a front view of a head mounting portion in a sixth embodiment of the invention, and FIG. 11 is a sectional view similar to FIG. 3, showing a head mounting portion in a seventh embodiment of the invention. Lower cylinder 2 near cylinder 4 2 turns ti
; b 6: Hesodo pace 7: Screw 92 mounting pace 11a, llh: JJ line 14: Voltage regulator 15: Woobo circuit 16: Atmosphere correction circuit 17; Special record/re-pattern generator 18: Identification piece 19: Piezoelectric element installation Board AI-A7: Piezoelectric element removal ■I: Head Clarion Co., Ltd. Agent Ashi 1) Naoe Figure 1 Figure 2 Figure 1b Figure 4 Figure 5 Figure 6 AI (A21 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 1')

Claims (1)

[Claims] A piezoelectric element member for head angle adjustment is interposed between the head and a head rotating member such as a rotating cylinder or a rotating disk, and an adjustment voltage corresponding to a required angle adjustment amount is applied to the piezoelectric element member. Azimuth adjustment device for rotating head.