JPS5917887B2 - Bi-resonant piezoelectric filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a support structure for an H-type bi-resonant piezoelectric vibrator and a structure of a P-wave device using the same.

A bi-resonant oscillator is a single oscillator that has two resonances in close proximity, and has characteristics equivalent to two conventional single-resonant oscillators. It has the feature of being able to construct a non-polar P-wave device.

If a dual-resonant oscillator is introduced, the number of oscillators can be reduced compared to, for example, a ladder configuration in order to realize an r-wave generator with the same guaranteed attenuation, and this will lead to expectations for miniaturization. Appropriate support and mounting structure for the resonant vibrator are the key to downsizing the f-wave device.

A vibrator must be supported so as not to hinder its vibration as much as possible, and support is usually provided at the nodes of vibration, and in the case of piezoelectric vibrators, in most cases it also serves as an electrical connection at the same time. .

Similar consideration must be given to the H-type bi-resonant piezoelectric vibrator, but here there is no vibration node common to the two resonances, nodal support is impossible, and the influence of support is unavoidable.

The so-called wire mount structure is known as a structure that minimizes the influence of support, and in order to reduce support stiffness due to vibration characteristics, a thin support wire diameter and a long support span are required. This is not necessarily appropriate as the support strength decreases.

A proposal similar to the wire mount structure was also made for the H-type bi-resonant piezoelectric vibrator, but as a result of various experimental studies, a new support structure with strong support strength and no problems in terms of vibration characteristics was discovered.

The basics of the support structure according to the present invention is that an H-shaped vibrator is arranged in the window of a holder, which is a U-shaped window frame with a conductive film in a pattern corresponding to a predetermined electrical connection on the front and back surfaces. A protrusion is formed on either the side edge of the transducer or the side edge of the window frame of the holder at the central position in the length direction. It has a structure in which it is connected with a conductive agent, either directly or through another auxiliary conductor, and serves both electrical connection and mechanical support.

According to this structure, the mechanical support strength is as strong as expected, and experimental results have confirmed that the influence on vibration characteristics is at a level that does not cause any problems, and it is an excellent structure that satisfies the necessary conditions for support. be.

The capacitor required when configuring a polarized f-wave device is made of ceramic material into a short shape, and this is placed in the opening of the holder window frame and incorporated so as to be directly connected to the window frame, thereby strengthening the window frame structure. If used in this way, the vibrator will be surrounded by four peripheries and will be mechanically protected.

Furthermore, by arranging mouth-shaped spacers on the front and back sides and covering them with an insulating film, the vibrator can be appropriately placed in the internal space, making it a mounting suitable for molded exteriors. This also has a positive effect on the mounting and exterior of the P-wave device.

Furthermore, in the case of an R-wave device having a multi-stage cascade configuration with a plurality of vibrators, the same can be achieved by making the holder into a so-called comb-shaped shape in which the U-shaped window frame is repeated and placing a composite capacitor at the comb-shaped opening. The effect remains unchanged, and furthermore, a more advanced f-wave device configuration is possible by stacking each layer in a layered manner while connecting each layer, and this structure has a large ripple effect.

This will be explained in detail below using examples.

Embodiment 1 Figure 1 is a circuit diagram of a polarized 455KH, zlF' wave device consisting of one H-type bi-resonant piezoelectric vibrator 1 and a polarized capacitor 3, and Figure 2 shows the assembly arrangement in the embodiment. surface view,
b is a rear view, and Fig. 3 is a perspective view showing the state in which spacers 7 are placed on the front and back of the assembly shown in Fig. 2 and covered with an insulating film 8. It is made from a so-called double-sided printed board that has a conductive film on the front and back sides with a board as the base, and there are markings on both the front and back sides of the window frame of the holder so that the predetermined circuit connection can be made after the vibrator 1 and capacitor 3 are assembled and connected. The arrangement pattern of the conductive film and the non-conductive film is determined in advance.

The holder has an outer diameter of 7 x 6 mm, a window cutout of 6 x 4 mm, and a thickness of 0.5 mm.

An external input terminal 11 is drawn out from a conductive film 11' on the window frame on the left side when viewed from the front, and an external common ground terminal 14 is drawn out from a conductive film 14' on the window frame from the right side to the connecting portion.

The back side is also on the left side (opposite side of the right window frame when viewed from the front side)
The external output terminal 13 is drawn out from the conductive film 13' on the window frame, and from the conductive film 12' on the window frame from the right side (the opposite side of the left window frame when viewed from the front) to the connection part, the output terminal 13 is connected to the conductive film 13' on the window frame as shown in FIG. According to the circuit, the ground terminal 12 must be pulled out, but since 12 and 14 are common ground terminals, bend the tip of the external common ground terminal 14, connect this tip to 12', and connect the common ground terminal 14 to 14. I try to let them do it.

The H-type bi-resonant piezoelectric vibrator 1 is made of a blank plate with a length of 4 mm, a width of 3.2 mm, and a thickness of 0.5 am, with a concave portion of 1.2 mm wide and 1.71 mm deep in the center in the width direction on both sides. It is inserted deep into the window of the holder 5 so that it does not touch the window frame in the formed form, and also so that it does not come into contact with the polarized capacitor when it is placed, which will be described later.
Here, the protrusion 6 formed on the side edge of the longitudinally central portion of the H-shaped vibrator exceptionally lightly contacts the left and right window frames of the holder.

Electrodes of the vibrator extend on both the front and back sides of the protrusion, and the electrodes of the vibrator and the conductive film of the holder are directly soldered (not shown) on both the front and back at the contact area between the protrusion and the window frame of the holder. It provides electrical connections and mechanically supports the vibrator.

After the support is completed, the frequency of the vibrator is adjusted by removing or adding mass at the front end of the image on the holder opening side, and a polarized capacitor 3 is arranged at the holder opening, and the conductivity between its electrode and the window frame is adjusted. The membranes are also soldered (not shown) to connect and support the capacitor 3.

Thus, the vibrator 1 and the capacitor 3 are firmly supported, and the vibrator 1 is surrounded by the holder 5 and the capacitor 3 on all four sides and is mechanically protected.

Regarding the vibration characteristics of the vibrator, there was concern about the extent of its influence due to the solidity of the support, but according to experimental examples, it was at a level that would not cause any practical problems.

There is no problem with the frequency since it is adjusted after support, and when estimating the Q characteristic from the operation of the P-wave device, the resonance peak of the dual resonance is damped by the input and output impedance and a flat passband is created between both resonances, but it is not ideal. The condition of 2 Ω with the mount wire support, which follows the conventional technology similar to that of the prior art, is reduced to 1 Ω with this support, so there is no problem in practical use.

Regarding the exterior of the P-wave device, which consists of a vibrator and a capacitor with the above structure, the vibrator is naturally mechanically protected by being surrounded on all four sides by a holder and a capacitor as outlined above. Only protection needs to be considered.

FIG. 3 is a perspective view illustrating the covering situation performed in the example according to this background, in which a mouth-shaped insulating spacer 7 is stacked on the front and back of the vibrator and capacitor assembly, and the outside is covered with an insulating film. 8, and further coated with a metal film for both mechanical strength and electrical shielding if necessary, and protected with a thermosetting resin as the outermost covering.

When coating an insulating film or metal film, the coating assembly is rectangular and has a clear outline, and simply wrapping the coating is sufficient, and even if the outermost resin shrinks during heat curing, the spacer can be used to prevent the coating from shrinking. The vibrator remains in free space without being compressed and reproduces the desired good characteristics.

From the above description of the embodiments, the structure of the present invention is not only excellent in supporting the vibrator, but also suitable for mounting as a P-wave device, such as capacitor placement and protection of the vibrator. The exterior of the f-wave device can also be done simply and reliably.

In the above embodiment, a polarized capacitor 3 is required to realize polarized P-wave characteristics, but in the case of non-polar characteristics, no capacitor is necessary.

However, from the above explanation, 3 not only acts as a capacitor but also protects the vibrator, so for non-polar characteristics, 3 must be understood as a protector that does not have a capacitor effect, and for convenience of explanation, 3 is named a capacitor. It must be interpreted in a broad sense as described above.

Embodiment 2 Although the previous embodiment deals with one vibrator, a similar configuration is possible when a plurality of vibrators are incorporated.

Figure 4 shows a two-stage cascade-connected R-wave generator using two dual-resonant oscillators, each configured with a polarity, 1 and 1' are dual-resonant oscillators, 2 is a coupling capacitor between stages, and 3 , 3' are polarized capacitors.

FIG. 5 shows the assembled structure of the embodiment for FIG. 4, where the three capacitors on the circuit are replaced by one composite capacitor 4.
This embodiment is similar to the first embodiment except that it is implemented in .

An H-shaped bi-resonant vibrator is arranged in each window of a holder 5 having two windows, and in this embodiment, a protrusion 6 is formed on the holder side, and the protrusion and the side edge of the longitudinal center of the vibrator are connected to each other. A light contact is made, and electrical connection and mechanical support of the vibrator are performed at the contact portion via a phosphor bronze thin wire (not shown).

According to experimental results, the effect of contact between the protrusion provided on the holder side and the vibrator as in this embodiment is greater than that of the contact in the first embodiment in which the protrusion is provided on the vibrator side. In order to alleviate the effect, the contact area of the protrusions is made to be at an acute angle smaller than that of the first embodiment, so that it is not easy to solder directly, and some of the solder on the front side is soldered to the back side through the gap. Since there is a possibility of problems such as the wires turning around, a thin phosphor bronze wire is interposed as an auxiliary conductor for prevention purposes.

The composite capacitor 4 is placed on top of the holder window opening in contrast to the first embodiment where it is inserted into the holder window opening.
This is only a partial change for ease of machining the holder, and the connection and holding conditions at the contact portion are the same as in the first embodiment.

It goes without saying that the vibrator and capacitor assembly assembled in this way can be coated in the same manner as in the first embodiment by simply changing the shape of the spacer, and the effects described earlier can be achieved in the same way as in the first embodiment. The same will be maintained in the same way.

As described above, the support structure for the vibrator is constructed according to the first embodiment that targets one vibrator and the second example that uses two vibrators.
Combined arrangement structure of vibrator and capacitor for holder,
The covering structure was also explained in detail, and direct effects and ripple effects were mentioned.

It is possible to form a block by further arranging a plurality of layers of the above-mentioned combination in a laminated manner, interconnecting each layer, and partially changing the external terminal wires. The exterior can be constructed in the same manner as described in the embodiment, and a small, high-quality r-wave device can be constructed firmly.

[Brief explanation of drawings]

Fig. 1 shows a polarized r-wave device circuit composed of a bi-resonant resonator 1 and a polarized capacitor 3, and Fig. 2 shows the assembled structure of the resonator and capacitor in this embodiment, and a is a plane. Figures 1 and 2b are actual side views, in which 1 is an H-shaped bi-resonant ceramic resonator, 3 is an antarctic capacitor made of ceramic material, 5 is a conductive film 11', 14' and 12' on the front and back surfaces of the window frame. The vibrator 1 is placed inside the window, and the protrusion 6 provided on the side edge of the central part in the longitudinal direction of the vibrator lightly contacts the side edge of the window frame. are electrically connected with a conductive agent and mechanically support the vibrator. A capacitor 3 is placed in the opening of the window and similarly connected and supported to the holder using a conductive agent. External input/output terminal IL13, external common ground terminal 14.12
is drawn out from the roaring conductive film of the holder. FIG. 3 shows a situation in which opening-shaped spacers 7 are arranged on the front and back surfaces of the molded exterior of the vibrator and capacitor assembly, and these are first inner-coated with an insulating film 8. Figure 4 is a circuit diagram of a P-wave device with polar characteristics that is a two-stage cascade connection using two twin-resonant resonators 1 and 1', where 2 is a coupling capacitor between stages, and 3°3' is a polarized It is a capacitor. Fig. 5 is an assembly structure diagram of the embodiment compared to Fig. 4, in which a total of three capacitors required on the circuit are realized by one composite capacitor 4, and a protrusion 6 for supporting the vibrator is provided on the holder side. Other than the above, the configuration is similar to that of FIG. 2, and the numbering is also similar to that of FIG. 2.

Claims (1)

[Claims] 1 A conductive film is applied to the front and back surfaces of the window frame of a U-shaped holder having one or more windows, or a comb-like shape that repeats the same, in accordance with a predetermined electrical connection. A resonant piezoelectric vibrator is arranged, a protrusion is provided on either the vibrator or the holder at a central position in the longitudinal direction of the vibrator, and the protrusion and the side edges of the holder or the vibrator are in slight mechanical contact. , the two are electrically bridge-connected with a conductive agent directly or through an auxiliary conductor at the contact portion, and mechanically fixed, and a capacitor or a composite capacitor is disposed in the window opening of the holder. The contact portions of the holder are bridge-connected with a conductive agent and mechanically fixed, and external electrical terminal wires and interconnection wires are connected to predetermined locations on the conductive film of the window frame of the holder. Piezoelectric P wave device.