JPH04196614A - Support structure for dual mode piezoelectric filter element or the like - Google Patents

Abstract

PURPOSE:To attain miniaturization and thin profile by connecting a tip of a hot lead to an electrode lead of the dual mode piezoelectric filter element and providing a truncated chevron shaped elastic conductor support on the middle of the surface of a conductor base. CONSTITUTION:A hot lead penetrating through a base 16 air-tightly with insulation is provided in the vicinity of both sides of the conductor base 16 and an elastic conductor support 18 formed in a truncated chevron shape is spot-welded in the middle of the surface. Both corners at lower ridge of the dual mode filer element 11 are engaged with both free ends of the support 18, both shoulders of the filter element 11 are supported by the hot lead 17 and the four points are fixed by a conductive adhesives 19. An electrode lead 13 of a split electrode 12 and an earth electrode lead 15 of a common earth electrode 14 on the rear side are connected electrically to the hot lead 17 and the support 18 respectively and fixed mechanically. Thus, a gap S between the lower ridge of the filter element 11 and the surface of the base 16 is reduced and miniaturization and thin profile are attained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a filter element holding structure for reducing the height of a piezoelectric device, particularly a vertically held piezoelectric dual mode filter.

(Prior art) Conventionally, a piezoelectric resonator 2, for example, a dual mode crystal filter element, has divided electrodes 2.2 on the - main surface of a crystal blank l and electrode leads extending from these to the outer periphery of the blank, respectively, as shown in Fig. 3. A common ground electrode 4 is formed on the opposing surfaces of 3, 3, and a hot lead 6.6 that penetrates the conductor base 5 with airtight insulation, and an earth lead erected on the conductor base 5 by a method such as welding. 7 with conductive adhesive 8 to the base 5.
However, it was common to adopt a holding structure in which the cap is fixed in a vertical shape and then covered with a cap 9.

Nowadays, as the demands for smaller and thinner electronic devices become stricter, piezoelectric devices, which are the electronic components used in these devices, are also required to be smaller. Since the piezoelectric device fixes the ground electrode lead end at the center of the lower edge of the piezoelectric resonator and the ground lead 7 with a conductive adhesive 8, a corresponding space S is required, but this space S is extremely reduced. Doing so will not only make the bonding work difficult, but also increase the rigidity of the protruding part of the ground lead 7 to the surface of the base 5, which will cause the crystal plate l to be fixed even more rigidly, resulting in a decrease in the Q of the resonator and resonance. There was a drawback that this resulted in an increase in the change in resonance frequency between before and after the child was fixed.

(Object of the Invention) The present invention has been made to eliminate the defects of the conventional piezoelectric device holding structure as described above, and although it is a vertical support structure, by reducing its height, it is compact and compact.
A dual-mode piezoelectric filter element that can meet the demands for thinning and can prevent a reduction in resonance Q due to vibration energy leaking from a fixed part when a piezoelectric resonator is miniaturized. The purpose is to provide a holding structure.

(Summary of the Invention) In order to achieve the above object, a holding structure for a dual mode piezoelectric filter element according to the present invention has the following configuration.

That is, a pair of hot lead ends passing through the conductor base through hermetic insulation are connected to the electrode lead ends extending from the split electrodes of the double moat piezoelectric filter element to be held, respectively, and an inverted cross-shaped elastic conductive fixed to the center of the surface of the conductor base. Both free ends of the conductor support are connected and fixed to a pair of ground leads extending from the opposing common ground electrode of the element to both sides of the edge facing the conductor base surface of the element.

(Embodiments of the Invention) Hereinafter, a holding structure for a dual mode piezoelectric filter element of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention.

In this figure, 11 is a crystal substrate constituting a dual mode piezoelectric filter element, and is a rectangular blank plate whose height is minimized to reduce the overall height of this device. A divided electrode 12.12 and an electrode lead 13.13 are formed from these toward the corner of the shoulder part of the blank plate, and a common ground electrode 14 is formed on the opposite surface of the blank plate 11, and a common ground electrode 14 is formed on both the lower edges of the blank plate 11. A pair of ground electrode leads 15.15 are formed extending to the corners.

On the other hand, near both sides of the base 16 formed by coining the conductor block, there are hot leads I7, which pass through the base with airtight insulation. 7 is provided, and an elastic conductor support 18 formed in an inverted crosshair shape is spot welded to the center of the surface of the base 16, and if necessary, an earth lead 19 is welded to the back surface of the base.

Both corners of the lower edge of the dual mode filter element 11 are engaged with both free ends of the support 18 as described above, and both shoulders of the filter element 11 are supported by the hot leads 17 and 17, and these four points are electrically conductive. If fixed with adhesive 19, the electrode leads 13.13 of the divided electrodes 12.12 and the earth electrode leads 15.13 of the common earth electrode 14 on the back side thereof.
15 are respectively the hot lead 17, 17 and support 1
Since the support 18 is connected to the earth lead 19 via the base 16, it is also completely grounded.

By holding the dual-mode piezoelectric filter element in this way, the gap S between the lower edge of the filter element +1 and the surface of the base 16 can be minimized, and the base of the inverted eight-shaped support 18 can be The beam length extending from the center to both sides can be made sufficiently long, resulting in low rigidity.
It will therefore be understood that the filter element can be fixed flexibly.

Furthermore, by adopting such an element holding structure, the element is held and fixed at a position as far away as possible from the center of vibration, that is, the center of the electrode, which reduces the leakage of vibration energy from the holding part and reduces the Q of resonance. It is also obvious that there is an advantage that the insertion loss, sheave factor, and other characteristics of the filter are not degraded.

By the way, the inverted eight-shaped support 18 as described above is shown in FIG.
As shown in a), an identification part 19 located at the center and a pair of elastic arms 2 extending obliquely upward from the fixed part 19 in the shape of both wings.
0.20 and a holding part 21.21 provided at the tip of each elastic arm 20.20, and the wide fixing part 19 has a flat shape suitable for spot welding to the heel surface. The elastic arms 20 and 20 extending from the fixing part 19 may also be formed of a flexible structure that can be elastically moved upward. Further, the holding portion 21.21 is given a U-shaped cross section suitable for supporting the corner of the r edge facing the base surface of the piezoelectric filter element 11, and the conductive adhesive dropped on the face portion is used to attach the ground electrode lead. 19. Configure to identify and connect the face parts of 19.

Furthermore, RJ Hot Read 17. +7 is a fork 22 made of a thin conductive plate, for example, as shown in FIG. The assembly process can be simplified by welding the edge through the gap of the fork and shifting the lower edge so that both corners are received by the holding parts 21.21 at both ends of the inverted figure-of-eight support 18. Dew.

Below, an example will be described in which a filter element is supported using a rectangular blank plate whose height is smaller than its width, in order to better meet the purpose of the present invention, which is to reduce the height of the D/'1 chair as much as possible. It goes without saying that the holding structure of the filter element according to the present invention can be similarly applied to an iE rectangular element, and the structure of the tip of the hole lead terminal 17 can also be applied to the iE rectangular element. It is not necessarily limited to this embodiment; a conventional coil-shaped clip may also be used.

Hereinafter, the present invention has been explained by taking the case of holding a double moat piezoelectric filter as an example, but it goes without saying that the present invention is not limited to this and may be suitable for holding a 2-port piezoelectric resonator, for example. (Effects of the Invention) Since the present invention is configured as explained below,
It meets the demand for miniaturization and thinning of dual-mode power station filters, etc., and is extremely effective in preventing the lowering of filter characteristics, especially Q due to leakage of vibration energy.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of a holding structure for a vertical dual mode piezoelectric filter element according to the present invention, and FIGS. 2(a) and (b) are holding members suitable for use in the present invention. FIG. 3 is a perspective view showing different embodiments of the present invention, and FIG. 3 is a configuration explanatory diagram showing a holding structure of a conventional dual mode piezoelectric filter. +1...Double mode piezoelectric filter element, 12...Divided electrode, 13...Electrode lead, 14...Common earth electrode, ]5...Earth electrode lead, +7...Hot lead, 18 ...Inverted eight-figure support, Patent applicant Fukushima Toyo Tsushinki Co., Ltd. Toyo Tsushinki Co., Ltd. Agent Patent attorney Hitoshi Suzuki Figure 1 Figure 2

Claims (1)

[Claims] A pair of lead tips passing through the conductor base in an airtight insulation manner are connected and fixed to hot lead ends extending from a split electrode of a dual-mode piezoelectric filter element, etc., and an inverted eight-shaped shape is connected and fixed to the central part of the surface of the conductor base. Extending from both free ends of the elastic conductor support and a common ground electrode facing the divided electrodes of the dual mode piezoelectric filter element via the element substrate to both ends of the edge facing the conductor base surface of the base plate of the filter element, etc. By connecting and fixing the pair of ground electrode lead ends, the element is fixed substantially perpendicularly to the conductor base surface, and the gap between the conductor base surface and the lower edge of the element facing the conductor base surface is reduced. A holding structure for a dual mode piezoelectric filter element, etc., which is characterized by its extreme characteristics.