JPH06151243A - Laminated filter - Google Patents

Abstract

PURPOSE:To enable the capacity of zero resetting capacitor to be adjusted after the baking step of the title laminated filter by a method wherein the end of the first extension electrode and the end of the second extension electrode are closely opposed on the surface of the laminated filter and then an epoxy resin, etc., is to be bonded onto the opposed part. CONSTITUTION:A green sheet laminated with a first layer S1, second layer S2 and a third layer S3 is printed with a conductive paste respectively forming a first capacitor electrode 20 and a second capacitor electrode 30 and then a fourth layer S4 is laminated on the conductive paste to be baked. Later, the fourth layer S4 is printed with another conductive paste forming the first and second extension electrodes 11, 41 and a gland electrode G3. At this time, the end lie of the first extension electrode 11 and the other end 41e of the second extension electrode 41 are closely opposed on the surface of a laminated band pass-filter F1 to form a zero resetting capacitor CO. Finally, an epoxy resin E is to be bonded onto the closely opposed part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a high frequency filter used in mobile communication equipment such as mobile phones and cordless phones, in which dielectrics such as ceramics are laminated, and an inductor is formed between or on each of these layers. A central conductor to
The present invention relates to a laminated filter provided with an electrode forming a capacitor.

[0002]

2. Description of the Related Art As an example of a conventional laminated bandpass filter, the one described in Japanese Patent Laid-Open No. 3-265205 is known.

This conventional laminated bandpass filter is
From the bottom layer, ceramics, center conductor, ceramics, zero-point forming capacitor electrode, ceramics, first electrode, ceramics, second electrode, ceramics,
The shield electrodes are stacked in this order, two input / output terminals are provided on the side surface of the multilayer bandpass filter, each input / output terminal is connected to each of the end portions of the two first electrodes, and is opposed via ceramics. An input / output capacitor is formed by the first electrode and the second electrode, and the end portion of the second electrode and the open end of the center conductor are connected by a side electrode other than the above, and via the ceramics. The opposing second electrode and shield electrode form a resonant capacitor that is connected in parallel with the center conductor.

Further, the first electrode on the input terminal side and the zero-point forming capacitor electrode face each other, and the first electrode on the output terminal side and the zero-point forming capacitor electrode face each other. And a zero-point forming capacitor is configured by these. The zero point forming capacitor constitutes a kind of trap circuit provided at a predetermined frequency in order to suppress an interference signal of an adjacent channel or suppress unnecessary radiation at the zero point (fn ₁ ). In the above conventional example, the zero point forming capacitor electrode is
The whole is surrounded by ceramics.

[0005]

When manufacturing a multilayer bandpass filter, the electrode for the zero-point forming capacitor, the area of the first electrode, the distance between these electrodes, the dielectric constant of the ceramics, etc. Variation occurs in the capacitance of the zero-point forming capacitor, which causes variations in the zero-point frequency and reduces the level drop at the zero point. The characteristics of the pass filter vary.

However, in the above-mentioned conventional example, there is a problem that it is practically impossible to adjust the capacitance of the zero-point forming capacitor after firing the multilayer bandpass filter. That is, the main factors that can change the capacitance of the zero-point forming capacitor are the electrode for the zero-point forming capacitor, the area where the first electrodes face each other, the distance between these electrodes, and the dielectric constant of the ceramics. Since the zero point forming capacitor electrode is surrounded by ceramics, the electrode cannot be trimmed, and the surface of the first electrode facing the zero point forming capacitor electrode is also made of ceramics. Since it is surrounded, the necessary portion of the first electrode cannot be trimmed. Therefore, the area where the zero-point forming capacitor electrode and the first electrode face each other cannot be changed. Further, it is impossible to change the distance between the zero point forming capacitor electrode and the first electrode, or to change the dielectric constant of the ceramics after firing the multilayer bandpass filter. Therefore, in the above conventional example, the capacitance of the zero-point forming capacitor cannot be adjusted after firing the multilayer bandpass filter.

The above-mentioned problem also occurs in filters other than the laminated bandpass filter.

In order to solve this problem, the first extension electrode and the second extension electrode are connected to the two input / output terminals respectively, and the end portion of the first extension electrode and the end portion of the second extension electrode are connected. Part is installed on the surface of the multilayer filter and is closely opposed to each other.
It is conceivable to form a zero-point forming capacitor by the closely facing portions.

However, in such a case, there is a problem in that the desired characteristics cannot be obtained when the capacitance of the zero point forming capacitor formed by the close facing portions is insufficient.

According to the present invention, an extension electrode is connected to an input / output terminal, an input / output capacitor is formed by the extension electrode and a capacitor electrode facing each other through ceramics, and an inductor formed by a central conductor is opened. In the multilayer filter having the capacitor electrode connected to the end, the resonance capacitor formed between the capacitor electrode and the ground electrode, and having the zero-point forming capacitor, after the multilayer filter is fired, the zero-point forming capacitor It is an object of the present invention to provide a multilayer filter whose capacity can be adjusted sufficiently.

[0011]

According to the present invention, a first extension electrode and a second extension electrode are respectively connected to two input / output terminals, and each extension electrode and a capacitor electrode face each other via ceramics. By this, an input / output capacitor is formed, a capacitor electrode is connected to the open end of the inductor formed by the center conductor, a resonance capacitor is formed between the capacitor electrode and the ground electrode, and a zero point forming capacitor is provided. In the laminated filter, an end portion of the first extension electrode and an end portion of the second extension electrode are installed on the surface of the laminated filter and face each other in close proximity, and the proximity facing portion constitutes a zero point forming capacitor. Then, an epoxy resin or the like is attached to the above-mentioned close and opposing portions.

[0012]

According to the present invention, the end portion of the first extension electrode and the end portion of the second extension electrode are installed on the surface of the laminated filter and face each other in close proximity, and the zero-point forming capacitor is formed by the proximity opposing portion. Since an epoxy resin or the like is adhered to the close opposing portion, the capacitance at the close opposing portion increases, and the capacitance of the zero-point forming capacitor can be sufficiently adjusted after firing the multilayer filter.

[0013]

FIG. 1 is a perspective view showing a laminated bandpass filter F1 which is an embodiment of the present invention, and FIG.
FIG. 4 is a left side view of a vertical section taken along line II-II in FIG. FIG. 3 shows each of the layers S0 to S0 in the above embodiment.
It is a top view of each layer S0-S4 at the time of dividing into S4.

This embodiment shows four layers S1, S2, S.
3 and S4, the first layer is formed on the green sheet (ceramics before firing) of the first layer S1 in the manufacturing process.
Conductive paste for forming the central conductor L1 and the second central conductor L2 is printed, the green sheet of the second layer S2 is laminated on the conductive paste, and the conductive material forming the ground electrode G2 is formed on the green sheet. Conductive paste is printed, a green sheet of the third layer S3 is laminated on the paste, and the first capacitor electrode 20 and the second capacitor S2 are formed on the green sheet.
The conductive pastes for forming the respective capacitor electrodes 30 are printed, and the green sheet of the fourth layer S4 is stacked and baked on this.

After the firing, a conductive paste for forming the first extension electrode 11, the second extension electrode 41 and the ground electrode G3 is printed on the upper surface of the fourth layer S4. In this case, the end portion 11e of the first extension electrode 11 and the end portion 41e of the second extension electrode 41 are the same as the laminated bandpass filter F.
The upper surface of 1 closely opposes each other, and a zero-point forming capacitor C0 is formed by this proximate facing portion. The first
The extension electrode 11 and the ground electrode G3 face the capacitor electrode 20 via the ceramics, and the second extension electrode 41 and the ground electrode G3 face the capacitor electrode 30 via the ceramics. There is. The first central conductor L1 and the second central conductor L2 form an inductor.

Then, the epoxy resin E is attached on the portion of the end portion 11e and the end portion 41e which are close to each other and face each other.

Further, in FIG. 1, connecting conductors 21 and 3 are provided.
The surface on which 1 exists and the surface on which the extension electrodes 11 and 41 exist,
Assuming that the front surface and the upper surface of the multilayer bandpass filter F1 are the first input / output electrode 10 connected to the extension electrode 11 and the extension, respectively, the left side surface, the right side surface, the back surface, and the bottom surface of the multilayer bandpass filter F1. A conductive paste that forms the second input / output electrode 40 connected to the electrode 41, the ground electrode G, and the ground electrode G1 is printed. On the front surface of the multilayer bandpass filter F1, the central conductor L
1 for connecting the capacitor 1 and the capacitor electrode 20
Is printed, and the conductive paste that forms the connection conductor 31 that connects the central conductor L2 and the capacitor electrode 30 is printed.

FIG. 4 is a vertical cross-sectional view of the surface taken along the line IV-IV in FIG. 3 as seen from the direction of the arrow. In this figure, the epoxy resin E is placed on the extension electrodes 11 and 41 and does not exist between the end portions 11e and 41e, but the epoxy resin E also exists between the end portions 11e and 41e. May exist. As described above, the extension electrode 1
When the epoxy resin E is placed on Nos. 1 and 41, the capacitance of the zero point forming capacitor C0 formed at the close opposing portions of the end portions 11e and 41e is such that the epoxy resin E is not placed. Increase more than if.

FIG. 5 is an equivalent circuit diagram of the above embodiment.

The first extension electrode 11, the first capacitor electrode 20 and the ceramics form a first input / output capacitor C1, and the second extension electrode 41, the second capacitor electrode 30 and the ceramics. A second input / output capacitor C4 is formed. Further, the first resonance capacitor C is provided between the first capacitor electrode 20 connected to the first center conductor L1 and the ground electrodes G2 and G3.
2 is formed, and the second resonance capacitor C3 is formed between the second capacitor electrode 30 connected to the second center conductor L2 and the ground electrodes G2 and G3.

FIG. 6 is an explanatory view of another embodiment of the present invention, and is a view seen from the same direction as FIG.

In the embodiment shown in FIG. 6 (1), a fourth layer S4a is provided instead of the fourth layer S4 shown in FIG. The fourth layer S4a is obtained by pasting the conductor 50 on the epoxy E in the fourth layer S4, whereby
More capacitance can be obtained as the zero-point forming capacitor C0.

In the embodiment shown in FIG. 6 (2), a fourth layer S4b is provided instead of the fourth layer S4 shown in FIG. The fourth layer S4b is the same as the fourth layer S4a in that the conductor 51 is attached onto the epoxy E in the fourth layer S4, but a part of the conductor 51 is connected to the extension electrode 11. It is different from the fourth layer S4a. The capacitance value of the zero-forming positive capacitor C0 in the fourth layer S4b shown in FIG. 6 (2) is larger than the capacitance value of the zero-point forming capacitor C0 in the fourth layer S4a shown in FIG. 6 (1).

In the embodiment shown in FIGS. 6A and 6B, the capacitance of the zero point forming capacitor C0 may be adjusted by trimming the conductors 50 and 51. In this case, trimming is performed. Conductor 50, 51
Another epoxy resin may be attached to the above. As a result, the trimming portions provided on the conductors 50 and 51 are covered, so that aesthetics are not impaired.

FIG. 7 shows that the capacitances of capacitors other than the zero point forming capacitor C0 in the above embodiment are also adjusted,
It is explanatory drawing at the time of covering the trimming part used for these adjustments with epoxy E1, and is a top view of a filter.

In this embodiment, first, the conductive paste for the extension electrodes 11 and 41 and the ground electrode G3 is printed on the fourth layer S4, and then the trimming portions T1 and T2, if necessary.
T3 and T4 are provided. That is, when the extension electrode 11 is trimmed to form the trimming portion T1, the input / output capacitor C1
The capacitance of the resonance capacitor C2 can be reduced by trimming the portion of the ground electrode G3 facing the capacitor electrode 20 to form the trimming portion T2. Also, the ground electrode G
By trimming the portion of the capacitor 3 facing the capacitor electrode 30 to form the trimming portion T3, the capacitance of the resonance capacitor C3 can be reduced, and by trimming the extension electrode 41 to form the trimming portion T4, The capacitance of the output capacitor C4 can be reduced. The trimming is performed by sandblasting, a laser beam or the like.

Then, the closely facing portions of the end portions 11e and 41e and the trimming portions T1, T2, T3 and T4 are attached so as to be covered with the epoxy E1. As a result, the capacitance of the zero point forming capacitor C0 is increased, and the trimming portions T1, T2, T3, and T4 are not exposed.
The beauty of the product is increased. Further, the epoxy E1 can be stamped and the like, and the aesthetics of the product is further increased.

Further, the ends 11e and 41e may be arranged so as to closely face each other on the surfaces other than the upper surfaces of the laminated band pass filters F1 and F2, and the zero point forming capacitor C0 may be formed.
The electrode forming the and the other electrodes C1 to C5 may be provided on different surfaces. Furthermore, although the ground electrode G3 is provided on the upper surface of the multilayer bandpass filter in each of the above embodiments, the ground electrode G3 may be removed from the upper surface.

In the above embodiment, the inductor formed by the center conductor L1 and the resonance capacitor C2 form a first-stage resonance circuit, and the inductor formed by the center conductor L2 and the resonance capacitor C3 form a second stage. Although the resonance circuit is configured, that is, the bandpass filter is configured by the two-stage resonance circuit, the bandpass filter may be configured by the one-stage resonance circuit as illustrated in FIG. 8.

The embodiment shown in FIG. 8 is an example of a bandpass filter in the case where the resonance circuit is composed of one stage. From the circuit diagram shown in FIG. 5, the central conductor L2 and the resonance capacitor C
3 is deleted, and the left end of the input / output capacitor C4 in the figure is connected to the right end of the input / output capacitor C1 in the figure.
That is, in FIG. 3, the capacitor electrodes 20 and 30 are connected and the central conductor L2 is removed, which is the embodiment shown in FIG. Further, the above-described embodiment may be applied to a bandpass filter including a resonance circuit having three or more stages.

Further, in the above embodiment, the first-stage resonant circuit including the inductor constituted by the central conductor L1 and the resonant capacitor C2, the inductor constituted by the central conductor L2 and the resonant capacitor C3 are constituted. This is an example of inductive coupling with the second-stage resonance circuit described above. However, as shown in FIG. 9, these may be capacitively coupled or inductively coupled + capacitively coupled. Good.

The embodiment shown in FIG. 9 is an example of the case where the first-stage resonant circuit and the second-stage resonant circuit are capacitively coupled. Instead of the fourth layer S4 shown in FIG. It uses a 4-layer S4c. The fourth layer S4c is printed with a conductive paste forming the coupling electrode 60 so that the fourth layer S4 shown in FIG. 3 does not come into contact with other electrodes (the extension electrodes 11 and 41 and the ground electrode G3). In this case, the coupling electrode 60 is connected to the capacitor electrode 20 via ceramics.
And 30 are printed so as to overlap. By doing so, the first-stage resonance circuit and the second-stage resonance circuit are capacitively coupled via the coupling electrode 60 and the ceramics. In this case, the third layer to the zeroth layer shown in FIGS. 9 (2) to (5) are the third layer to the third layer shown in FIGS. 3 (2) to (5).
Same as the 0th layer. According to the above, when the capacitances of the capacitors C0, C1, C2, C3, and C4 are adjusted,
The value of the capacitance in the capacitive coupling between the resonance circuit at the second stage and the resonance circuit at the second stage can be adjusted at the same time.

In the above embodiment, the end 11e and the end 4
Epoxy resins E and E1 are adhered on the portion facing closely to 1e, but instead of the epoxy resins E and E1,
Glass or dielectric pieces may be used.

Further, although the band pass filter has been described in the above embodiments, filters other than the band pass filter, such as a band elimination filter, a high pass filter, a low pass filter, etc., can be explained in the same manner as above.

[0035]

According to the present invention, the first extension electrode and the second extension electrode are respectively connected to the two input / output terminals, and each extension electrode and the capacitor electrode face each other through the ceramics. A multilayer type having an input / output capacitor, a capacitor electrode connected to the open end of an inductor formed of a center conductor, a resonance capacitor formed between the capacitor electrode and a ground electrode, and a zero point forming capacitor. In the filter, it is possible to sufficiently adjust the capacitance of the zero-point forming capacitor after firing the multilayer filter.

[Brief description of drawings]

FIG. 1 is a perspective view showing a multilayer bandpass filter F1 which is an embodiment of the present invention.

2 is a vertical cross-sectional left side view of a vertical cross section taken along line II-II in FIG. 1. FIG.

FIG. 3 is a plan view of each of the layers S0 to S4 when the above embodiment is divided into each of the layers S0 to S4.

FIG. 4 is a vertical cross-sectional view of the surface cut along the line IV-IV in FIG. 3 as viewed in the direction of the arrow.

FIG. 5 is an equivalent circuit diagram of the above embodiment.

6 is an explanatory view of another embodiment of the present invention, and is a view seen from the same direction as FIG.

FIG. 7 is an explanatory diagram in the case where the capacitances of capacitors other than the zero-point forming capacitor C0 are also adjusted and the trimming portion used for these adjustments is covered with epoxy E1 in the above-described embodiment.

FIG. 8 is a diagram showing an equivalent circuit in another embodiment of the present invention.

FIG. 9 is a diagram showing an example in which the first-stage resonant circuit and the second-stage resonant circuit are capacitively coupled in the embodiment shown in FIGS. 1 to 5;

[Explanation of symbols]

F1 ... Laminated bandpass filter, L1 ... First central conductor, L2 ... Second central conductor, G, G1, G2, G3 ... Ground electrode, C0 ... Zero point forming capacitor, T1 ... First input / output Capacitance adjusting trimming portion of capacitor C1, T2 ... Capacitance adjusting trimming portion of first resonant capacitor C2, T3 ... Capacitance adjusting trimming portion of second resonant capacitor C3, T4 ... Capacity of second input / output capacitor C4 Adjustment trimming portion, E, E1 ... Epoxy resin, 10 ... First input / output terminal, 11 ... First extension electrode, 11e ... End portion, 20 ... First capacitor electrode 21 ... Connection conductor, 30 ... Second capacitor electrode, 31 ... Connection conductor, 40 ... Second input / output terminal, 41 ... Second extension electrode, 41e ... End portion, 50 ... Conductor, 60 ... Coupling electrode.

Claims (6)

[Claims] 1. A first extension electrode and a second extension electrode are respectively connected to two input / output terminals, and each extension electrode and a capacitor electrode face each other via a dielectric,
A first input / output capacitor and a second input / output capacitor are formed, the capacitor electrode is connected to an open end of an inductor formed by a central conductor, and a resonance capacitor is provided between the capacitor electrode and the ground electrode. In the multilayer filter having a capacitor for forming a zero point, the end portion of the first extension electrode and the end portion of the second extension electrode are placed on the surface of the multilayer filter and are in close proximity to each other. The zero-point forming capacitor is constituted by the close-facing portion, and the epoxy resin, glass, or dielectric piece is attached to the close-facing portion. 2. The conductor according to claim 1, which is a conductor facing the closely facing portion with the epoxy resin, the glass or the dielectric piece sandwiched therebetween, and is attached to the epoxy resin, the glass or the dielectric piece. A multilayer filter having a conductor. 3. The end portion of the first extension electrode, the end portion of the second extension electrode, an electrode forming the first input / output capacitor, and the second portion according to claim 1. Electrodes forming input / output capacitors,
The electrode forming the resonance capacitor is provided on the same surface, the electrode forming the first input / output capacitor, the electrode forming the second input / output capacitor, and the resonance capacitor are formed. The above-mentioned epoxy resin, the above-mentioned glass, or the above-mentioned dielectric piece is attached to the electrode. 4. The multilayer filter according to claim 1, wherein a resonator including the inductor and the resonant capacitor is provided in one or more stages. 5. The resonator according to claim 4, wherein a plurality of stages of resonators each including the inductor and the resonance capacitor are provided, the plurality of stages of resonators are inductively coupled, capacitively coupled, or inductively coupled. A multilayer filter characterized by being coupled in any one of + capacitive coupling. 6. The resonator according to claim 4, wherein a plurality of stages of resonators each including the inductor and the resonance capacitor are provided, and when the plurality of stages of resonators are capacitively coupled, the plurality of stages of resonance are provided. For capacitively coupling a container, an end of the first extension electrode, an end of the second extension electrode, an electrode forming the first input / output capacitor, and the second input / output. An electrode for forming a capacitor for use with an electrode for forming the resonance capacitor is provided on the same surface.