JPH0536928U - Ceramic filter - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent damage to the ceramic substrate where the ceramic resonator is mounted due to impact such as dropping. [Structure] In this ceramic filter, a groove 501 having a depth such that each thickness shear vibration of the ceramic vibrators 101 and 102 does not come into contact with the ceramic substrate 301 has a surface on which the ceramic vibrators 101 and 102 are mounted.
It is provided in.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a ceramic filter, and more particularly to a surface-mounted ceramic filter.

[0002]

[Prior art]

 As shown in FIGS. 3 and 4, a conventional surface-mounted ceramic filter includes an extremely thin flat ceramic substrate 601, rectangular (strip-shaped) ceramic vibrators 101 and 102, and electrodes 201, 202 and 203. , 204 and a conductive adhesive 401. FIG. 3 is a perspective view of this ceramic filter. 4 (a), (b) and (c) are a front view, a back view and a side view showing the substrate 601 and the electrodes 201, 202, 203 and 204 of the ceramic filter shown in FIG.

Here, the ceramic substrate 601 has a cutout f in which two opposite sides of the substrate 601 on which the ceramic vibrators 101 and 102 are mounted are cut out in a U-shape. These notches f are provided to prevent the vibrating portions h and i of the vibrators 101 and 102 from coming into contact with the substrate 601 when the ceramic vibrators 101 and 102 generate thickness shear vibration. . The vibrators 101 and 102 are mounted on the substrate 601 across the U-shaped notch f. The substrate 601 has electrodes 201, 202 and 203 on the surface on which the vibrators 101 and 102 are mounted, and has electrodes 204 on the opposite surface. Here, each of the electrodes 201, 202, 203 and the electrode 204 form a capacitive element (capacitor: 21, 22, 23 in FIG. 5) with the substrate 601 interposed therebetween. The vibrators 101 and 102 are fixed to the substrate 601 at connection points a and c, respectively, and are connected to the electrodes 201 and 203 at connection points b and d, respectively. The vibrators 101, 102 at the connection points a, b, c, d are bonded to the substrate 601 and the electrodes 201, 203 with a conductive adhesive 401. Further, the lengths of the vibrators 101 and 102 are selected such that the thickness shear vibrations of the vibrators 101 and 102 are not transmitted to the connection points a, b, c and d at both ends. Although the notch f of the ceramic substrate 601 is notched in a U-shape, an example in which the notch f is cut out into a rectangular hole is also possible.

FIG. 5 shows an equivalent circuit of the ceramic filter configured as described above. More specifically, the electrode 204 common to the three electrodes 201, 202, and 203 to form the three capacitors 21, 22, and 23 is the electrode 201, 202, and 203 with the substrate 601 interposed therebetween. Is done. The electrode 201 of the capacitor 21 is connected to one end of the vibrator 101 at a connection point b, and the electrode 203 of the capacitor 23 is connected to one end of the vibrator 102 at a connection point d. Further, the other ends of the vibrator 101 and the vibrator 102 are connected to the connection points a and c, respectively, and the electrode 202 of the capacitor 22 is connected to the connection point e. After the surface mounting, the connection points a, c, and e are used as lead-out terminals for connection with the outside.

Thus, a T-shaped ceramic filter having three terminals at connection points a, c, and e is configured.

[0006]

[Problems to be solved by the device]

 In this conventional ceramic filter, since a notch f that is partially cut is provided at the end of a very thin flat ceramic substrate 601, the remaining notched substrate on which the ceramic vibrators 101 and 102 are mounted is mounted. The portion is vulnerable to impact, and is inevitably damaged from the cutout angle g of the ceramic substrate 601 due to impact such as dropping.

[0007]

[Means for Solving the Problems]

 A ceramic filter according to the present invention is formed on first, second and third electrodes formed on a first main surface with a space between each other and on a second main surface facing the first main surface. A ceramic substrate having a fourth electrode and forming a capacitive element at a position corresponding to each of the first, second and third electrodes and the fourth electrode; Rectangular first and first electrodes arranged on the main surface, one end of which is connected to the first and second electrodes and the other end of which serves as first and second lead-out portions to the outside, which generate thickness shear vibrations. And two ceramic vibrators, and a groove having a depth such that each thickness shear vibrating portion of each of the first and second ceramic vibrators does not contact the ceramic substrate is provided on the first main surface side. The one end of the third electrode serves as a third lead-out portion to the outside.

Also, in the ceramic filter according to the present invention, the first and second ceramic oscillators are respectively arranged at opposite ends of the first main surface of the ceramic substrate, and the grooves are provided at the opposite ends. Each is provided.

[0009]

【Example】

 Next, the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a surface-mounted ceramic filter according to an embodiment of the present invention. 2A, 2B and 2C are a front view, a back view and a side view showing the ceramic substrate 301 and the electrodes 201, 202, 203 and 204 of the ceramic filter shown in FIG.

This ceramic filter is composed of a very thin flat ceramic substrate 301, rectangular ceramic vibrators 101 and 102, electrodes 201, 202, 203 and 204, and a conductive adhesive 401. Here, the ceramic substrate 301 has grooves 501 cut in a concave shape on two opposite sides of a portion where the ceramic vibrators 101 and 102 are mounted on one surface of the substrate 301. The groove 501 is provided to prevent the vibration parts h and i of the vibrators 101 and 102 from coming into contact with the substrate 301 when the ceramic vibrators 101 and 102 generate thickness shear vibration. The vibrators 101 and 102 are mounted on the substrate 301 across the groove 501. Further, the substrate 301 has electrodes 201, 202 and 203 on the surface on which the vibrators 101 and 102 are mounted and has electrodes 204 on the opposite surface. Here, each of the electrodes 201, 202, 203 and the electrode 204 form a capacitor (see 21, 22, 23 in FIG. 5) with the substrate 301 interposed therebetween. The vibrators 101 and 102 are fixed to the substrate 301 at connection points a and c, respectively, and are connected to the electrodes 201 and 203 at connection points b and d, respectively. The vibrators 101, 102 at the connection points a, b, c, d are bonded to the substrate 301 and the electrodes 201, 203 with a conductive adhesive 401. Further, the lengths of the vibrators 101 and 102 are selected such that the thickness shear vibration of the vibrators is not transmitted to both ends. The connection points a, c and e are used as lead-out terminals for external connection after surface mounting.

Thus, the same ceramic filter having the three terminals of the connection points a, c, and e and having the equivalent circuit shown in FIG. 5 is configured.

As described above, this ceramic filter is mounted with the ceramic vibrators 101 and 102 by providing the grooves 501 on one surface of two opposite sides of the ceramic substrate 301 on which the ceramic vibrators 101 and 102 are mounted. The edge of the board is strong against external impact. The groove provided on the substrate 301 may have a depth such that the vibrating portions h and i of the vibrators 101 and 102 do not contact the substrate 301, and the shape and position can be arbitrarily selected.

[0013]

[Effect of the device]

 As described above, according to the present invention, a ceramic substrate can be added from the outside by providing a groove on one surface of the ceramic substrate on which the ceramic oscillator is arranged, with a depth such that the vibrating portion of the ceramic oscillator does not contact the ceramic substrate. It is more resistant to shock and can be prevented from being damaged by falling.

[Brief description of drawings]

FIG. 1 is a perspective view showing a ceramic filter according to an embodiment of the present invention.

FIG. 2 is a front view (a), a rear view (b) and a side view (c) of the ceramic substrate shown in FIG.

FIG. 3 is a perspective view of a conventional ceramic filter.

4 is a front view (a), a rear view (b) and a side view (c) of the ceramic substrate shown in FIG.

5 is an equivalent circuit diagram of the ceramic filter shown in FIG.

[Explanation of symbols]

 21,22,23 Capacitor 101,102 Ceramic vibrator 201,202,203,204 Electrode 301 Ceramic substrate 401 Conductive adhesive 501 Groove a, b, c, d, e Connection point h, i Vibration part

Claims (2)

[Scope of utility model registration request] 1. A first main surface, a first electrode, a second electrode, and a third electrode, which are formed at a distance from each other, and a fourth main surface, which is opposed to the first main surface. Each of the first, second and third electrodes and the fourth electrode.
A ceramic substrate that forms a capacitive element at a position corresponding to the electrode of, and one end of each of the first main surfaces is connected to the first and second electrodes and the other end is connected to the outside. 1
And a rectangular first and second ceramic oscillator that generates thickness-shear vibration as a second lead-out portion, and each thickness-shear vibration portion of the first and second ceramic oscillators is the ceramic. A ceramic filter, wherein a groove having a depth that does not contact the substrate is provided on the first main surface side, and one end of the third electrode is used as a third lead-out portion to the outside. 2. The first and second ceramic oscillators are arranged at opposing ends of the first main surface of the ceramic substrate, and the grooves are provided at the opposing ends. The ceramic filter according to claim 1.