JP2005093836A - Laminated composite device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated composite device provided with a surge protection circuit, the spark gap of which can be formed smaller than those of prior art. <P>SOLUTION: A first discharge piece pattern 51 connected to a ground terminal 1 is formed to the surface of one ceramic layer in two upper and lower ceramic layers configuring a layered ceramic board 8 in the laminated composite device 3, a second discharge piece pattern 52 connected to an antenna terminal is formed on the surface of the other ceramic layer, both the discharge piece patterns 51, 52 are formed respectively to have sharpened tips, and the tips of both the discharge piece patterns 51, 52 are close to each other by sandwiching the ceramic layers. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a multilayer composite device for configuring various electronic circuits equipped in an electronic device such as a mobile phone.

In a cellular phone, an antenna duplexer is provided in order to share one antenna between a reception system and a transmission system, and the antenna duplexer is generally configured by a multilayer composite device (30) as shown in FIG. Has been.
In the multilayer composite device (30), a multilayer ceramic substrate (6) is composed of a plurality of ceramic layers (60) to (69) as shown in FIG. 9, and the surface of the uppermost ceramic layer (60) is formed. A plurality of chip parts (7) are mounted on the surface, and inductor patterns and capacitor patterns are formed on the surfaces of the second and subsequent ceramic layers (61) to (69). These chip parts (7 ) And circuit element patterns are connected to each other to form a shared antenna circuit (see Patent Documents 1 and 2).

  By the way, in a mobile phone, for example, when a user touches the antenna and the antenna is charged with static electricity, the static electricity becomes a surge voltage and is applied to the antenna sharing circuit, thereby forming an elastic surface constituting the antenna sharing circuit. Circuit elements such as wave filters may be destroyed.

Therefore, in order to protect the electronic circuit from the surge voltage, a pair of discharge piece patterns that should form a spark gap is formed on the surface of the circuit board so as to face each other, and one discharge piece pattern is used as a signal line of the electronic circuit. A surge protection circuit in which the other discharge piece pattern is connected to the ground has been proposed (Patent Document 3).
If such a surge protection circuit is connected to the antenna sharing circuit, even if a surge voltage is applied to the antenna sharing circuit, a spark is generated between the pair of discharge strip patterns, and the surge voltage is converted into light energy and heat energy. It is converted and disappears. Therefore, there is no possibility that circuit elements such as a surface acoustic wave filter are destroyed.
Japanese Patent No. 3048592 Japanese Patent No. 3067612 JP-A-8-293647

However, in the conventional surge protection circuit, since a pair of discharge strip patterns are simultaneously formed on the substrate surface by screen printing using a single screen, the spark gap should be 100 μm or less for screen printing accuracy. Therefore, there is a problem that the function as a surge protection circuit is not sufficient.
SUMMARY OF THE INVENTION An object of the present invention is to provide a multilayer composite device including a surge protection circuit capable of forming a spark gap smaller than the conventional one.

In the multilayer composite device according to the present invention, a multilayer dielectric substrate is configured by laminating a plurality of dielectric layers, and one or a plurality of circuit element patterns are formed on the surface of each dielectric layer. The patterns are connected to each other to constitute an electronic circuit that should perform a predetermined function, and the laminated dielectric substrate is provided with a signal terminal and a ground terminal.
A first discharge piece pattern (51) connected to the ground terminal is formed on the surface of one of the two dielectric layers directly overlapping each other, and the other dielectric layer. A second discharge piece pattern (52) connected to the signal terminal is formed on the surface of each of the two discharge piece patterns (51) and (52). 51) The tips of (52) are arranged close to each other with the dielectric layer in between.

In the multilayer composite device of the present invention, the ends of the pair of discharge piece patterns (51) and (52) are opposed to each other with the dielectric layer interposed therebetween, and a spark is formed between the ends of both discharge piece patterns (51) and (52). A gap is formed. Therefore, when a surge voltage is applied to the signal terminal, a spark is generated between the tips of the discharge piece patterns (51) and (52), and the surge voltage is converted into light energy and heat energy and disappears.
Here, since the pair of discharge strip patterns (51) and (52) are formed on both sides of one dielectric layer, the distance between the tips of both discharge strip patterns (51) and (52), that is, the spark gap. Is defined by the thickness of the dielectric layer. In general, since the dielectric layer can be easily formed with a thickness of 50 μm or less, the spark gap is set to 50 μm or less.

In a specific configuration, the signal terminal is an antenna terminal (22) to which an antenna is to be connected. A circuit element pattern to be an inductor (4) is formed on the surface of the other dielectric layer, and the circuit element pattern is formed between the antenna terminal (22) and the second discharge piece pattern (52). In series.
In the specific configuration, the inductor (4) is interposed between the antenna terminal (22) and the pair of discharge piece patterns (51) and (52) to exert a high frequency cutoff function. High frequency signal leakage due to capacitive coupling between the discharge pattern (51) and (52) does not occur.

In a more specific configuration, the laminated dielectric substrate is covered with a metal chassis (1).
According to this specific configuration, even if a surge voltage is applied from the outside other than the antenna, the electronic circuit can be protected from the surge voltage by the shield function exhibited by the metal chassis (1).

  According to the multilayer composite device according to the present invention, the spark gap formed between the tips of the pair of discharge piece patterns can be formed smaller than the conventional spark gap limited by the accuracy of screen printing.

Hereinafter, the embodiment in which the present invention is implemented in a dual-band antenna duplexer will be described in detail with reference to the drawings.
As shown in FIG. 1, the antenna duplexer according to the present invention is configured by covering a multilayer composite device (3) with a metal chassis (1). The multilayer composite device (3) includes signal terminals such as antenna terminals and the like. A plurality of terminals (2) such as a ground terminal are provided.

FIG. 2 shows a circuit configuration of the multilayer composite device (3). The first band transmission / reception system (3a) and the second band transmission / reception system are connected to the diplexer (31) to which the antenna (10) is connected. (3b) is connected in parallel.
The first-band transmission / reception system (3a) is configured by connecting a surface acoustic wave filter (34) and a low-pass filter (35) to two switching terminals of a switch (32) that can be switched between reception and transmission. During reception, the first-band received signal R1 is output from the surface acoustic wave filter (34), and during transmission, the first-band transmission signal T1 is input to the low-pass filter (35).
The transmission / reception system (3b) of the second band is configured by connecting a surface acoustic wave filter (36) and a low-pass filter (37) to two switching terminals of a switch (33) that can be switched between reception and transmission. At the time of reception, the second band reception signal R2 is output from the surface acoustic wave filter (36), and at the time of signal transmission, the second band transmission signal T2 is input to the low-pass filter (37).
A spark gap (5) is connected to a signal line from the antenna (10) to the diplexer (31) through an inductor (4).

  As shown in FIG. 3, the spark gap (5) is formed between the layers of the multilayer ceramic substrate (8) constituting the multilayer composite device (3). That is, a pair of discharge strip patterns (51) and (52) are arranged on both sides across one ceramic layer, and the tips of both discharge strip patterns (51) and (52) are sharply pointed. 51) The tips of (52) are opposed to each other with a gap G corresponding to the thickness of the ceramic layer to form a spark gap (5).

  The multilayer ceramic substrate (8) is composed of a plurality of ceramic layers (80) (81) (82) (83)... Shown in FIGS. As shown in FIG. 4, chip parts such as a surface acoustic wave filter chip (71), a diode (72), a coil (73), and a capacitor (74) are mounted on the surface of the first ceramic layer (80). ing.

As shown in FIG. 5, the discharge piece pattern (51) having the sharp tip is formed on the surface of the second ceramic layer (81). The base end portion of the discharge piece pattern (51) is Connected to the ground terminal (21). Further, as shown in FIG. 6, a line pattern (41) constituting the inductor (4) is formed on the surface of the third ceramic layer (82), and the tip of the line pattern (41) is formed. The above-mentioned pointed discharge piece pattern (52) is formed in the portion, and the base end portion of the line pattern (41) is connected to the antenna terminal (22).
The pattern formation shown in FIG. 5 and the pattern formation shown in FIG. 6 are performed by screen printing in separate steps using separate screens, so the positions of the tips of the pair of discharge strip patterns (51) and (52) The alignment can be performed with high accuracy without being limited in accuracy in a common screen printing process. As a result, the tips of both discharge strip patterns (51) and (52) are aligned at the same plane position with high accuracy.

  Further, as shown in FIG. 7, a circuit pattern constituting the diplexer (31) is formed on the surface of the fourth ceramic layer (83), and the circuit pattern is connected to the antenna terminal (22).

  In the multilayer composite device (3) described above, the distance between the tips of the pair of discharge piece patterns (51) and (52) where the spark gap (5) is to be formed matches the thickness of one ceramic layer. It will be. Here, since it is easy to form the ceramic layer with a thickness of 50 μm or less, for example, about 20 μm, the distance between the tips of the pair of discharge strip patterns (51) and (52), that is, the spark gap (5) is thereby reduced. It can be set to a very small value of about 20 μm.

Therefore, when the antenna (10) is charged and a surge voltage is applied to the antenna terminal (22) of the multilayer composite device (3), even if the surge voltage is relatively low, both discharges are generated. Sparks are reliably generated between the tips of the single patterns (51) and (52), and the surge voltage is converted into light energy and heat energy and disappears. In this way, the surface acoustic wave filters (34), (36), etc. constituting the multilayer composite device (3) are protected from surge voltage.
Since the ceramic layer interposed between the pair of discharge piece patterns (51) and (52) is excellent in heat resistance, there is no possibility that the ceramic layer is destroyed due to generation of sparks.

  In addition, since the multilayer composite device (3) is covered with the metal chassis (1), even if a surge voltage is applied from the outside other than the antenna, the multilayer composite device (3) is protected by the shielding function exhibited by the metal chassis (1). Device (3) is protected from surge voltages.

Further, an inductor (4) is interposed between the antenna terminal (22) and the pair of discharge piece patterns (51) and (52), thereby exhibiting a high frequency cutoff function and a pair of discharge piece patterns (51) and (52). ) Between the antenna (10) and the high-frequency signal input from the antenna (10) passes through the inductor (4) and the pair of discharge strip patterns (51) and (52). There is no risk of leakage to the ground.
Therefore, the high frequency signal input from the antenna (10) is input to the diplexer (31) without causing any loss.

It is a perspective view which shows the external appearance of an antenna sharing device. It is a block diagram which shows the circuit structure of the multilayer composite device which concerns on this invention. It is a partially broken perspective view which expands and shows the principal part of this laminated type composite device. It is a top view of the ceramic layer of the 1st layer. It is a top view of the ceramic layer of the 2nd layer. It is a top view of the ceramic layer of the 3rd layer. It is a top view of the ceramic layer of the 4th layer. It is a perspective view of the conventional multilayer composite device. It is a disassembled perspective view of this laminated type composite device.

Explanation of symbols

(1) Metal chassis
(2) Terminal
(21) Ground terminal
(22) Antenna terminal
(3) Multilayer composite device
(4) Inductor
(41) Track pattern
(5) Spark gap
(51) Discharge strip pattern
(52) Discharge strip pattern
(71) Surface acoustic wave filter
(72) Diode
(8) Multilayer ceramic substrate

Claims (4)

  A laminated dielectric substrate is formed by laminating a plurality of dielectric layers, and one or a plurality of circuit element patterns are formed on the surface of each dielectric layer, and these circuit element patterns are connected to each other to have a predetermined function. In a multilayer composite device in which a signal terminal and a ground terminal are provided on the multilayer dielectric substrate, one of two dielectric layers directly overlapping each other is formed. A first discharge strip pattern (51) connected to the ground terminal is formed on the surface of the dielectric layer, and a second discharge strip pattern (connected to the signal terminal) is formed on the surface of the other dielectric layer. 52) is formed, and both discharge strip patterns (51) and (52) are each formed with a pointed tip, and the tips of both discharge strip patterns (51) and (52) are close to each other with the dielectric layer in between. Multi-layer composite device characterized in that Nest.   The multilayer composite device according to claim 1, wherein the signal terminal is an antenna terminal (22) to which an antenna is to be connected.   A circuit element pattern to be an inductor (4) is formed on the surface of the other dielectric layer, and the circuit element pattern is connected in series between the antenna terminal (22) and the second discharge piece pattern (52). The multilayer composite device according to claim 2, wherein the multilayer composite device is interposed in the multilayer composite device.   The multilayer composite device according to any one of claims 1 to 3, wherein the multilayer dielectric substrate is covered with a metal chassis (1).

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