JPS60107726A - Deflecting arm device - Google Patents

Abstract

PURPOSE:To suppress positively an unnecessary vibration by sticking an intermediate part of a supporting member roughly orthogonal to a displacement direction and a longitudinal direction, in the vicinity of the tip part of a bimorph piezoelectric element, fixing both end parts to a substrate through the second piezoelectric element, and impressing a voltage corresponding to a deflecting voltage. CONSTITUTION:The first piezoelectric element 20 is displaced in accordance with an impressed deflecting voltage, and simultaneously, a voltage corresponding to the deflecting voltage is impressed to terminals 31, 32 and 33, 34, too, and a voltage by which the polarizing direction in the second piezoelectric elements 29, 30 is promoted in the deflecting direction of the tip part of the first piezoelectric element 20 is impressed. As a result, the second piezoelectric elements 29, 30 expand and contract in the deflecting direction of the first piezoelectric element 20, a displacement quantity of the second piezoelectric elements 29, 30 is added to a deflection quantity of the first piezoelectric element 20 and the deflection quantity is increased, and an unnecessary vibration of the first piezoelectric element 20 is suppressed by an elastic force of the second piezoelectric elements 29, 30.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a deflection arm installation for supporting a recording/reproducing head of a VTR (video tape recorder).

Prior Art In a helical scan type VTR, etc., in order to accurately reproduce the information recorded on the video track of a magnetic tape, the video head must always scan the center position on the video track to be reproduced. becomes. For this purpose, the scanning position of the video head with respect to the video trunk is detected, a correction signal is generated based on the detection result, and this is supplied to a deflection arm device that supports the video head so that the video head can be positioned properly. A so-called tracking control method that maintains this has been secretly proposed.

The conventional deflection arm device Wt used in this type of tracking control is typically one that utilizes a bimorph piezoelectric element, which is shown in FIG. 1 and will be briefly explained. The Pymol 7 pressure element is one electrically polarized H
-, A ceramic element is laminated and bonded, and bending in the longitudinal direction υ゛ is caused by applying an uneven voltage to each ceramic element, and the direction of bending and the amount of displacement are determined by the polarity of the applied voltage and the amount of displacement. Determined by size. In Figure 1, such a bimorph piezoelectric element is
Indicated by This bimorph piezoelectric element 1 has a pair of upper and lower pressures of 7u.
a ceramic element 2.3, each ceramic element 2.
Electrodes 4, 5, 6, and T are disposed on the upper and lower surfaces of electrodes 4, 5, and 3, respectively, and bonded to the hJ layer. The polarization directions of each ceramic element 2 and 3 correspond to the same direction. And this bimorph pressure′
The rear end of the element 1 is fixed to a support base 8 in a rotating drum of a VTR, and a video head (not shown) is installed at the other end. Therefore, 't4L pole 4 located at the upper and lower ends
．． If a predetermined deflection voltage is applied to the terminal 9.10 so that 7 and li 4i5+ 5.6 located in the middle have the same polarity, the tip of the bimorph piezoelectric element 1 will be displaced in the direction of the arrow in the figure. , the video head is also displaced6.
The tracking system described in 17 can be performed.

Incidentally, as the deflection voltage applied to the bimorph piezoelectric element 1, a ν1 white wave voltage (VH) as shown in FIG. 2 α, a rectangular wave voltage, a square wave voltage, etc. are used. When such a deflection voltage (VH) is applied to the bimorph piezoelectric element 1, the bimorph piezoelectric element 1 responds to the magnitude of the foot pressure and, as shown in FIG. ), that is, accompanied by the occurrence of non-J4j vibration (W).

This vibration (w) is a unique resonance frequency (f, etc.) determined by the material structure and shape of the bimorph piezoelectric element 1, and is expressed by the following formula (7). E: The Young V\ρ of the piezoelectric ceramic element. Such unnecessary vibration!l!1l (W) obstructs the video head's dragging 1b1] control and prevents the proper scanning position 1θ from 51: , which improves image quality, and should be removed or reduced as much as possible.

Purpose: In view of the above, the present invention eliminates or temporarily attenuates the unnecessary filter vibrations of the conventional deflection arm arrangement and arrangement, improves its responsiveness, and also improves its responsiveness. 16
, and a deflection arm device t1. which can perform deflection 11JJ with high precision. It is in the tf5 offering.

8a Essentially, in order to achieve the above object, the present invention uses the first pressure I'1 as the base (after the child bimorph 11-' quasi-element, with the VJ capital as the base and the tip as the end). The main component is the above-mentioned Bimorph 71 Tij J (1), which is equipped with a deflection arm that bends its tip in an upright position in response to the applied deflection voltage.

The middle part of the support part 4>1 which is approximately IH intersecting with the displacement direction and the longitudinal direction of this piezoelectric element is fixed near the tip bar IX of the element, and both ends of this support part are connected with a second pressure '1' (the L element is is fixed to the substrate through the P/, and the deflection '
It is characterized by actively suppressing unnecessary vibrations by applying the tl pressure corresponding to the #B pressure.

EMBODIMENTS Below, 11 preferred embodiments further embodying the present invention will be described in detail with reference to Figures +j and +n.

FIG. 3 is a perspective view of the deflection arm device and L according to the present invention, and FIG. 4 is a 11.11 view of the i''II+ minute side of the same device.

First, all 14. The surface configuration will be explained. A bimorph piezoelectric element 20 serves as a first piezoelectric element.

This first piezoelectric element 2.0 is made by laminating I'J-, quasi-ceramic elements 21 and 22 vertically.
．． Gλ1z11A knowledge ML pole'i on each upper and lower surface of 22
: (Q setting, Thea F), each 'IM 41 (L is'
Pressure is applied from the twit elements 23 and 24 to a predetermined deflection '1.

In this first FE tlf, the strand 20 has the first bimorph pressure +I), which is exactly the same as the element 1.

On the other hand, 25 is a base fixed within the rotating drum of the VTR, and the entire body is shaped like a rectangular parallelepiped with a low height.
The middle part of 11 is cut out to form four parts 26. Therefore,
The lower surface of the rear end of the first piezoelectric element 20 is fixed to the middle 1hl 614 of the rear side of the base body 25, and the first pressure 1 on the lower side from this fixed part; The four parts 26 function to prevent this.

In addition, a video head 2T made of ferrite or the like is fixed to the upper surface of the tip i:z of the L element 20 and protrudes in the i direction, and the lower surface near the tip of the first piezoelectric element 20 is fixed to the upper surface of the tip i:z of the L element 20. The middle part of a rectangular plate-shaped support member 28 is fixed to the support member 28 (FIG. 4).The support member 28 is under a first pressure of 1M, particularly in the longitudinal direction, and in the displacement direction (vertical direction) and longitudinal direction (ail direction) of the element 20. For the backward direction), it is set up so that it is the direct father.

Furthermore, a second piezoelectric element 2 is provided under both ends of the support part shrine 28.
9, one end direction of -30 is fixed via an electrode,
The other end surface of the second piezoelectric element 29.30 is attached to the punishment base 25 via the electrode, and the polarization axis of the second piezoelectric element 29.30 coincides with the displacement direction of the first piezoelectric element 20. . Therefore,
Both ends of the support member 28 will be fixed onto the base body 25 via second piezoelectric elements 29,30. The second piezoelectric element 29, 30 can be made of, for example, the piezoelectric ceramic element of the first piezoelectric element 2o, or it can be formed as a laminate structure by laminating several rivet elements so that a large amount of displacement can be obtained. good. Further, the support member 28 has an intermediate portion connected to the first pressure 1L element 2.
In this case, both ends of the support member 28 are fixed to the second piezoelectric element 29 and 30, and one end of the support member 28 is fixed to the first piezoelectric element 20 and the other end is fixed to the second piezoelectric element 29 or 3°. It may also be supported cantilevered. In addition, in the coffin 3 diagram, @2 piezoelectric elements 29 and 3o
The electrodes attached to the terminals are connected to terminals 31 and 32 through lead wires, respectively.
and 33 and 34 are provided so that a voltage can be applied.

Next, the functions of the deflection arm device 6 according to the present invention will be explained. Now, in FIG. 3, it is assumed that a predetermined deflection voltage is applied to the terminals 23 and 24. This causes the first
The pressure element 20 is displaced in response to the applied deflection voltage.

On the other hand, at the same time as this deflection voltage is applied, a voltage corresponding to the deflection vehicle pressure is also applied to the terminals 31, 32 and 33, 34. In other words, the <'tj'L pressure is applied as the polarization direction (stitching direction) in the second piezoelectric elements 29 and 30 assists the deflection direction (displacement direction) of the tip of the first pressure '11L element 20. . As a result, the second pressure* elements 29 and 30 expand and contract in the direction of deflection of the first pressure element 20, and the first piezoelectric element 20
The displacement amount of the second piezoelectric element 29, 30 is added to the deflection flatness of , so that the deflection mk can be increased, and the first pressure 't
! The unnecessary vibration of the L element 20 is caused by the second pressure IiJ, the element 29.
It can be suppressed by a stretching force of 30.

In addition, the displacement position (Δl) of the second pressure 71 element 29.30 is Δ
lj = da @ *v (Tata L, ■: Applied ↑U pressure,
dss: EE electric constant), for example, V = 100V
Then, das is 5 U Ox I U-”m/l
', so Δ=0.01μ door.

In this case, if they are formed into a single-layer structure as described above and, for example, 50 sheets are laminated, the displacement position (Δl) will be 0.5 μm, and a sufficient displacement amount can be obtained.

Although the embodiment has been described above as a deflection arm device for displacing a video head in a VTR, the present invention is not limited to this, and can be applied to other deflection means similar to each glaze.

Effects of the Invention As described above, the deflection arm device according to the present invention can attenuate unnecessary vibrations caused by a predetermined applied voltage, improve responsiveness to deflection voltage, and always provide accurate and highly accurate deflection. It can be performed.

Moreover, in addition to the above, it is possible to enlarge the deflection company,
It has the technical effect of being widely applicable.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a conventional deflection arm device ζ1, M
'! Figure 1 a is a diagram of the deflection force waveform applied to the same device; , Figure 4 shows the interior
It is a partial side view of f4. 20...Bimorph H:, ton element (element 11) E element) 25...Base 28*--Support member 29.30...Second piezoelectric ice element VH...0 direction 1 pressure Patent applicant: Olympus Optical Industry Co., Ltd. No. 2) (G) (b)

Claims (2)

[Claims] (1) A deflection arm device in which a rear end of a bimorph piezoelectric element (feeder 1 piezoelectric element) is fixed to a base, a tip is a free end, and the tip is displaced in response to an applied deflection voltage. The first
An intermediate portion of a support member that is substantially orthogonal to the main direction and the longitudinal direction of the piezoelectric element is fixed, and both ends of the support member are fixed to the ¥111 substrate via a second piezoelectric element, and the second piezoelectric element is A deflection arm device characterized in that a voltage corresponding to the deflection voltage is applied. (2) The second piezoelectric element is characterized in that a laminated piezoelectric element is used. The deflection arm device according to item 1 of the scope of requirements for Iv.