JP6066588B2 - Piezoelectric oscillator - Google Patents

Description

  The present invention relates to a piezoelectric oscillator used in an electronic device or the like.

  Conventionally, a signal source such as a reference signal source or a clock signal source is mounted on an electronic device such as a cellular phone, and a piezoelectric oscillator is known as such a signal source.

  The piezoelectric oscillator includes an element mounting member, and a piezoelectric vibration element and an integrated circuit element mounted on the element mounting member. In the piezoelectric oscillator, the piezoelectric vibration element is electrically connected to a piezoelectric vibration element mounting pad provided at one end portion in the long side direction of the bottom surface of the upper concave portion of the element mounting member. In the piezoelectric oscillator, monitor terminals are provided at both ends in the long side direction on the bottom surface of the lower recess of the element mounting member.

  For example, in a piezoelectric oscillator used as a real-time clock or the like, a plurality of integrated circuit element mounting pads may be provided at the center in the long side direction on the bottom surface of the lower recess. Therefore, the lead wiring for electrically connecting the piezoelectric vibration element mounting pad and the integrated circuit element needs to be routed from one end to the other end in the long side direction.

JP 2008-5088 A

  However, if the distance between the output external terminal of the piezoelectric oscillator and the routing wiring is short, stray capacitance generated between the output external terminal and the routing wiring increases the negative resistance of the oscillation circuit, and the oscillation margin is small and the oscillation frequency is small. May not be stable.

A piezoelectric oscillator according to one aspect of the present invention has an upper recess and a lower recess and includes an element having a rectangular insulating base in plan view and external terminals provided at four corners on the lower surface of the insulating base. And a piezoelectric vibration element provided in the upper concave portion and an integrated circuit element provided in the lower concave portion. The element mounting member is provided on the bottom surface of the upper concave portion, and further includes a lead wiring that electrically connects the piezoelectric vibration element mounting pad to which the piezoelectric vibration element is connected and the integrated circuit element. One of the external terminals is an output external terminal, and in plan perspective, the output external terminal is provided on one of the two opposing sides of the insulating base, and the routing wiring is provided on the other of the two opposing sides. The substrate portion of the insulating base is composed of a single insulating layer .

  In the piezoelectric oscillator according to one aspect of the present invention, the output external terminal is provided on one of the two opposing sides of the insulating base and the lead-out wiring is provided on the other of the two opposing sides in a plan view. Therefore, a sufficient distance between the output external terminal and the routing wiring can be ensured, and the stray capacitance can be reduced. Therefore, the piezoelectric oscillator according to one aspect of the present invention can reduce the negative resistance of the oscillation circuit and sufficiently ensure the oscillation margin, so that a stable oscillation frequency can be obtained.

It is a longitudinal cross-sectional view which shows the piezoelectric oscillator in embodiment of this invention. It is a top view which shows the state which removed the cover member in the piezoelectric oscillator shown by FIG. It is a bottom view which shows the state which removed the integrated circuit element in the piezoelectric oscillator shown by FIG. It is a bottom view which shows the state which attached the integrated circuit element in the piezoelectric oscillator shown by FIG.

  Hereinafter, a real-time clock will be described with reference to the drawings as an example of a piezoelectric oscillator according to an exemplary embodiment of the present invention.

  As shown in FIG. 1, the piezoelectric oscillator 100 according to the embodiment of the present invention is mounted on an element mounting member 110, an integrated circuit element 120 mounted on the element mounting member 110, and the element mounting member 110. And a piezoelectric vibration element 130 electrically connected to the integrated circuit element 120. FIG. 1 is a longitudinal sectional view taken along the line AA in a state where the lid member 140 is attached to the piezoelectric oscillator 100 shown in FIG.

  As shown in FIGS. 1 to 3, the element mounting member 110 includes a substrate portion 111 a, a first frame portion 111 b provided on the upper surface of the substrate portion 111 a, and a first frame portion provided on the lower surface of the substrate portion 111 a. An insulating base 111 composed of two frame parts 111c, a pair of piezoelectric vibration element mounting pads 112a and 112b provided on the upper surface of the substrate part 111a, a routing wiring 115 connected to the piezoelectric vibration element mounting pad 112b, and a substrate A plurality of integrated circuit element mounting pads 113 provided on the lower surface of the portion 111a, a pair of monitoring terminals 114a and 114b, and a plurality of external terminals 116 provided on the lower surface of the second frame portion 111c. . Here, the concave portion on the upper surface of the element mounting member 110 is defined as an upper concave portion K1, and the concave portion on the lower surface is defined as a lower concave portion K2.

  In FIG. 3, the plurality of integrated circuit element mounting pads 113 are indicated as 113 a to 113 j by adding alphabets a to j after the reference numeral 113. The plurality of integrated circuit element mounting pads 113a to 113j include, for example, an output pad 113a, a ground pad 113b, a control pad 113c, a power pad 113d, a clock input pad 113e, an open pad 113f, an interrupt signal pad 113g, a data input / output pad 113h, A first input pad 113i and a second input pad 113j.

  In FIG. 4, the external terminals 116 are indicated as 116 a to 116 h by adding alphabets a to h after the reference numeral 116. The plurality of external terminals 116a to 116h are, for example, an output external terminal 116a, a ground external terminal 116b, a control external terminal 116c, a power supply external terminal 116d, a clock input external terminal 116e, an open external terminal 116f, an interrupt signal external terminal 116g, a data input This is the output external terminal 116h.

  As shown in FIG. 4, the plurality of external terminals 116a to 116h are, for example, an output external terminal 116a, a ground external terminal 116b, a control external terminal 116c, and an external power source at the four corners of the lower surface of the second frame portion 111c. For example, a clock input external terminal 116e, an open external terminal 116f, an interrupt signal external terminal 116g, and a data input / output external terminal 116h are provided on two long sides of the second frame portion 111c. Yes.

  The substrate portion 111a, the first frame portion 111b, and the second frame portion 111c are made of a ceramic material such as alumina ceramics or glass-ceramics. Moreover, the board | substrate part 111a is a rectangular flat plate shape in planar view, for example, as FIG.1 and FIG.2 shows. The first frame portion 111b is provided along the edge portion of the upper surface of the substrate portion 111a. The second frame portion 111c is provided along the edge portion of the lower surface of the substrate portion 111a.

  The piezoelectric vibration element mounting pad 112a provided on the upper surface of the substrate portion 111a is for monitoring provided on the lower surface of the substrate portion 111a via the first via conductor 117a as shown in FIGS. It is electrically connected to the terminal 114a. Further, the piezoelectric vibration element mounting pad 112b provided on the upper surface of the substrate portion 111a is provided on the lower surface of the substrate portion 111a via the second via conductor 117b, as shown in FIGS. It is electrically connected to the second input pad 113j.

  In addition, as shown in FIGS. 2 and 3, the routing wiring 115 connected to the piezoelectric vibration element mounting pad 112b provided on the upper surface of the substrate portion 111a is connected to the substrate portion via the third via conductor 117c. It is electrically connected to a monitor terminal 114b provided on the lower surface of 111a. Of the plurality of integrated circuit element mounting pads 113a to 113j provided on the lower surface of the substrate portion 111a, the first input pad 113i is electrically connected to the monitor terminal 114a as shown in FIG. Yes.

  A signal output from the integrated circuit element 120 is applied to the output pad 113a, and the output pad 113a is electrically connected to the output external terminal 116a. The ground pad 113b is electrically connected to the ground external terminal 116b, and a ground voltage is applied. The control pad 113c is electrically connected to the control external terminal 116c, and a signal (that is, a control signal) for controlling the output state of the integrated circuit element 120 is applied. The power supply pad 113d is electrically connected to the power supply external terminal 116d, and a power supply voltage is applied thereto. The clock input pad 113e is applied with a signal for interface communication and is electrically connected to the clock input external terminal 116e. The open pad 113f is electrically open and is electrically connected to the open external terminal 116f. The interrupt signal pad 113g is applied with an interrupt signal such as an alarm signal, a timer signal, and a time update signal, and is electrically connected to the interrupt signal external terminal 116g. An input / output signal such as an address signal and a data bit signal is applied to the data input / output pad 113h in synchronization with the clock signal, and is electrically connected to the data input / output external terminal 116h. The first input pad 113i and the second input pad 113j are electrically connected to the piezoelectric vibration element 130, and an output signal of the piezoelectric vibration element 130 input to the integrated circuit element 120 is applied.

  As shown in FIG. 3, the pair of monitoring terminals 114a and 114b have a quadrangular shape parallel to the short side and the long side of the upper recess K1. The pair of monitoring terminals 114 a and 114 b are terminals for measuring the output signal of the piezoelectric vibration element 130.

  As shown in FIG. 4, the integrated circuit element 120 is provided in the lower recess K <b> 2 and is electrically connected to the plurality of integrated circuit element mounting pads 113 of the element mounting member 110 by the solder bumps 122. Has been.

  As shown in FIG. 2, the piezoelectric vibration element 130 is provided in the upper recess K <b> 1, and is electrically connected to the piezoelectric vibration element mounting pads 112 a and 112 b of the element mounting member 110 by the conductive adhesive 132. It is connected to the. The piezoelectric vibration element 130 includes a piezoelectric element plate cut along a predetermined crystal axis, and a connection electrode and an excitation electrode formed on the piezoelectric element plate. The piezoelectric vibration element 130 is configured to cause tuning fork vibration at a predetermined frequency when a varying voltage from the outside is applied to the piezoelectric element plate via the connection electrode and the excitation electrode. For example, a tuning fork type crystal is used as the piezoelectric element plate. The upper concave portion K1 of the element mounting member 110 in which the piezoelectric vibration element 130 is accommodated is hermetically sealed by the lid member 140.

  Here, the positional relationship between the output external terminal 116a and the routing wiring 115 in the piezoelectric oscillator 100 of the present embodiment will be described with reference to FIGS.

  Among the plurality of external terminals 116a to 116d formed at the four corners on the lower surface of the second frame portion 111c, the output external terminal 116a is in the short side direction of the insulating base 111 as shown in FIG. It is provided on one end side. Here, the short side direction of the insulating substrate 111 is a virtual Y-axis direction in FIG. 4, and the one end side is an upward direction in the virtual Y-axis direction in FIG. 4.

  As shown in FIG. 2, the routing wiring 115 is connected to the piezoelectric vibration element mounting pad 112b provided on the upper surface of the substrate portion 111a, and has one end in the long side direction of the virtual axis of the insulating base 111. It is drawn from the part to the other end part. Further, the lead wiring 115 is provided on the other end side in the short side direction of the virtual axis of the insulating base 111 at a position not overlapping the piezoelectric vibration element 130 connected to the piezoelectric vibration element mounting pads 112a and 112b in the vertical direction. Yes. Further, the short side direction of the insulating substrate 111 is a virtual Y-axis direction in FIG. 2, and the other end side is a downward direction in the virtual Y-axis direction in FIG. 2.

  As described above, in the piezoelectric oscillator 100 according to the present embodiment, the output external terminal 116 a is provided on one end side in the short side direction of the insulating base 111, and the lead wiring 115 is provided on the other end side in the short side direction of the insulating base 111. Therefore, a sufficient distance between the output external terminal 116a and the routing wiring 115 can be secured. Thereby, the piezoelectric oscillator 100 according to the present embodiment has a stray capacitance generated between the output external terminal 116a to which the signal output from the integrated circuit element 120 is output and the lead wiring 115 connected to the piezoelectric vibration element mounting pad 112b. Can be reduced. Therefore, the piezoelectric oscillator 100 according to the present invention can reduce the negative resistance of the oscillation circuit and sufficiently ensure the oscillation margin, so that a stable oscillation frequency can be obtained.

  Note that the integrated circuit element mounting pads 113a to 113J provided on the lower surface of the substrate portion 111a are mounted on the third via conductor 117c connected to the routing wiring 115 of the piezoelectric oscillator 100 of the present embodiment. Therefore, there is no space for placing the integrated circuit element 120 in the area where the integrated circuit element 120 is mounted, and the integrated circuit element 120 is placed in a position that does not overlap in the vertical direction.

  Further, as shown in FIG. 2, the lead wiring 115 of the piezoelectric oscillator of the present invention includes a piezoelectric vibration element 130 connected to the piezoelectric vibration element mounting pads 112a and 112b provided on the upper surface of the substrate portion 111a. Since it can be formed at a position that does not overlap in the vertical direction, there is no possibility that the piezoelectric vibration element 130 and the routing wiring 115 are in contact with each other. Therefore, it is not necessary to provide the routing wiring 115 in the inner layer of the substrate portion 111a, and the substrate portion 111a of the insulating base 111 is formed. A single insulating layer can be formed. Therefore, the height of the piezoelectric oscillator 100 can be reduced.

  In the above-described embodiment, various changes and improvements can be made without departing from the scope of the present invention. For example, in the above-described embodiment, the tuning fork type piezoelectric vibration element 130 is shown as the piezoelectric element plate mounted in the lower concave space K2 of the piezoelectric oscillator 100. A surface wave element may be used.

DESCRIPTION OF SYMBOLS 100 ... Piezoelectric oscillator 110 ... Element mounting member 111 ... Insulation base | substrate 111a ... Substrate part 111b ... 1st frame part 111c ... 2nd frame part 112 ... Piezoelectric vibration Element mounting pad 113... Integrated circuit element mounting pad 114... Monitor terminal 115... Lead wiring 116 .. External terminal 117... Via conductor 120. DESCRIPTION OF SYMBOLS 130 ... Piezoelectric vibration element 132 ... Conductive adhesive 140 ... Lid member K1 ... Upper recessed part K2 ... Lower recessed part

Claims (1)

An element mounting member having an upper recess and a lower recess and including a rectangular insulating base in plan view and external terminals provided at four corners of the lower surface of the insulating base;
A piezoelectric vibration element provided in the upper recess,
An integrated circuit element provided in the lower recess;
With
One of the external terminals is an output external terminal,
The element mounting member is provided on a bottom surface of the upper concave portion, and further includes a lead wiring that electrically connects the piezoelectric vibration element mounting pad to which the piezoelectric vibration element is connected and the integrated circuit element. ,
In plan perspective, the output external terminal is provided on one of the two opposing sides of the insulating base, and the routing wiring is provided on the other of the two opposing sides ,
The piezoelectric oscillator according to claim 1, wherein the substrate portion of the insulating base is composed of a single insulating layer .

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