JP2010183324A - Constant-temperature piezoelectric oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compacted constant-temperature piezoelectric oscillator with high stability of frequency with respect to ambient temperature variations, by including a temperature control element that includes a thermosensor and a heating element. <P>SOLUTION: A circuit board 40 with circuit elements, such as, a crystal oscillator 30, a heating element 50, a thermosensor 60, an oscillating element 70 and a temperature control circuit element 80 jointed thereto, is supported to a plurality of metal pins 5a-5d erected on a base board 121. A lid body is arranged on the base board 121, including the circuit board 40 supported by the metal pins 5a-5d to be placed on the circuit board 40 through a space. The lid body includes a metal cover body 129 arranged to be put on the base board 121 with the circuit board 40 supported thereto, and a mold resin layer 95 which covers the outer peripheral surface of the metal cover body 129. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a piezoelectric oscillator used as a frequency control device and the like, and in particular, is provided with a temperature control element including a temperature sensing element and a heating element so as to stabilize the frequency against changes in ambient temperature. The present invention relates to a piezoelectric oscillator.

A piezoelectric oscillator such as a crystal oscillator is known as a frequency control device, and is incorporated in an electronic device such as a mobile communication device or a transmission communication device as a reference source for frequency or time. As an example of improving the frequency stability of such a piezoelectric oscillator, for example, a structure in which the inside of the piezoelectric oscillator is kept constant can output a highly stable frequency without being affected by temperature changes in the surrounding environment. There is a constant temperature type piezoelectric oscillator that can be used as a reference frequency source for a mobile communication base station or measurement / measurement equipment. In these fields, as the demand for smaller and lighter electronic devices has increased in recent years, the thermostatic piezoelectric oscillator built in electronic devices is required to be smaller and lighter from the market. It has been.
In order to meet such a demand, for example, in Patent Document 1, a so-called surface mount small piezoelectric vibrator of a package type is used, and this piezoelectric vibrator, a temperature control element, an oscillation element or the like is mounted. A constant temperature type piezoelectric oscillator in which the substrate is accommodated in a container composed of a base and a lid has been introduced.

The constant temperature piezoelectric oscillator (crystal oscillator) described in Patent Document 1 is surface-mounted on a circuit board (second circuit board) provided in a container composed of a base (first circuit board) and a lid (metal cover). A type piezoelectric vibrator, an oscillation element connected to the piezoelectric vibrator, a temperature control element including at least a temperature sensitive element, and a heating element connected to the temperature control element are mounted.
Here, as the piezoelectric vibrator, a so-called SMD (Surface Mount Device) type piezoelectric vibrator (crystal vibrator) in which a piezoelectric vibrating piece is sealed in a package is used. As the heating element, a chip resistor, which is also an SMD component, is used, each of which is effective in reducing the size and thickness.

  In the constant-temperature type piezoelectric oscillator having such a configuration, the heating element uses Joule heat generated by supplying power to the heating element as a heat source, and passes through the temperature control element based on the temperature detected by the temperature-sensitive element. By controlling the power supplied to the container, the temperature inside the container is achieved.

JP 2005-341191 A

However, in the constant-temperature piezoelectric oscillator described in Patent Document 1, the heat capacity of a container including a base and a metal lid, and the size of the gap from the inner wall of the lid to the piezoelectric vibrator and the circuit board on which they are mounted, Depends on. For this reason, when trying to reduce the size of the main body (container) of the constant temperature type piezoelectric oscillator, the gap between the inner wall of the lid and the piezoelectric vibrator becomes smaller as the size of the main body (container) becomes smaller. Therefore, there is a possibility that the frequency characteristics may become unstable due to the influence of an external temperature change, and it is difficult to reduce the size.
Further, in the constant temperature type piezoelectric oscillator using the small SMD type crystal resonator as described above, a frequency shift due to thermal damage, which was not a problem with a large volume piezoelectric resonator, may become a problem. there were.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 A constant temperature type piezoelectric oscillator according to this application example includes a surface mount type piezoelectric vibrator in which a piezoelectric vibrating piece is housed in a package, a circuit board to which the piezoelectric vibrator is bonded, and the circuit board. An oscillation element connected to the piezoelectric vibrator, a temperature control element arranged on the circuit board, and a heating element connected to the temperature control element, the base and the lid A thermostatic piezoelectric oscillator housed in a container comprising: a lid having a resin layer on a part of the outer surface of the constant temperature piezoelectric oscillator, and at least the inner surface for heating A metal layer is provided on a surface facing the main surface of the element.

According to this configuration, since the surface of the container lid that is a part of the outer surface of the thermostatic piezoelectric oscillator is configured by the resin layer, it is possible to improve the heat capacity by adjusting the thickness of the resin layer. The influence of external temperature changes on the physical part such as a piezoelectric vibrator can be suppressed.
In addition, since the metal layer is provided on at least the main surface of the heating element on the inner surface of the lid, the absorption of the heat of the heating element into the resin layer is suppressed and the heat inside the container is reduced. Therefore, the inside of the container can be efficiently heated and kept warm and kept in a constant temperature state.
Therefore, it is possible to provide a small-sized constant temperature type piezoelectric oscillator having an efficient and stable heating and heat insulation structure and having a highly accurate and stable oscillation characteristic.

  Application Example 2 In the constant temperature piezoelectric oscillator according to the application example, the lid body includes a metal cover body as the metal layer and a mold resin layer as the resin layer covering the metal cover body. Features.

  According to this configuration, in a conventional constant temperature type piezoelectric oscillator in which a physical part such as a piezoelectric vibrator is housed in a container including a base and a metal cover body as a lid, at least the metal cover body is covered with the mold resin. By forming the layer, a structure that is hardly affected by external temperature changes can be obtained. Therefore, even when downsized, it is possible to manufacture a constant temperature type piezoelectric oscillator that is hardly affected by external temperature changes and that has a highly accurate and stable oscillation characteristic by a relatively simple manufacturing process.

  Application Example 3 The constant temperature piezoelectric oscillator according to the application example is characterized in that the metal layer of the lid is formed of a metal film formed on the surface of the resin layer.

  In this configuration, for example, the metal cover body is used as the metal layer by forming a metal layer made of a metal film by sputtering, vapor deposition, or plating on the original inner wall of a lid formed by molding a resin. Therefore, it is possible to provide a smaller constant temperature type piezoelectric oscillator having a smaller number of parts than the case where the lid is configured.

  Application Example 4 The constant temperature piezoelectric oscillator according to the application example is characterized in that the heating element is provided in contact with the metal layer.

  According to this configuration, the entire interior of the container can be kept in a stable and constant temperature state by radiant heat generated by the metal layer heated by the heating element, and the frequency temperature characteristics of the constant temperature type piezoelectric oscillator can be stabilized. Can do.

The top view which illustrates typically the constant temperature type crystal oscillator of 1st Embodiment as a constant temperature type piezoelectric oscillator seeing from an upper side. FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1 for schematically explaining the constant temperature crystal oscillator according to the first embodiment. The top view which illustrates typically the constant temperature type crystal oscillator of 1st Embodiment seeing from the bottom face side. (A) is a top view which illustrates typically the crystal oscillator as a piezoelectric vibrator, (b) is CC sectional view taken on the line of (a). Sectional drawing which shows the constant temperature type | mold crystal oscillator of 2nd Embodiment typically. Sectional drawing which shows the modification of a constant temperature crystal oscillator typically.

  Hereinafter, a constant temperature crystal oscillator as one embodiment of a constant temperature piezoelectric oscillator will be described with reference to the drawings.

(First embodiment)
1 to 3 schematically illustrate a constant temperature crystal oscillator according to the present embodiment, FIG. 1 is a plan view seen from above, and FIG. 2 is a cross-sectional view taken along line AA in FIG. 3 is a plan view seen from the bottom side. In FIG. 1, for convenience of describing the internal configuration of the constant temperature crystal oscillator, a part of the lid that forms the outer shape of the constant temperature crystal oscillator is cut out. FIGS. 4A and 4B illustrate a crystal resonator as a piezoelectric resonator used in the constant temperature crystal oscillator of the present embodiment, where FIG. 4A is a plan view and FIG. 4B is a CC line of FIG. It is line sectional drawing. Note that, in (a), for the sake of convenience in explaining the internal configuration of the crystal resonator, a part of the lid 29 bonded to the upper portion of the crystal resonator is cut out.

〔Crystal oscillator〕
First, the crystal resonator 30 provided in the constant temperature crystal oscillator 1 will be described.
As shown in FIG. 4, a so-called SMD type (surface-mount type) in which a quartz crystal resonator element 10 as a piezoelectric resonator element is bonded and sealed in a vibrator package 20 is connected to the constant temperature crystal oscillator 1 of the present embodiment. ) Crystal resonator 30 is used.
Since the SMD type crystal resonator 30 has been reduced in size and thickness, it is advantageous in reducing the size and thickness of the constant temperature crystal oscillator 1. In addition, the SMD type crystal resonator 30 standardized as a surface mount component is, for example, a type of crystal resonator that is sealed by covering a crystal resonator element bonded to a substrate with a cylindrical cap. It is not necessary to cut or mold the lead wire for external connection according to the connection terminal shape of the external board, and it is easy to automate mounting on the external board, which is advantageous for simplification of mounting process and cost reduction It is.

  In FIG. 4A, the quartz crystal resonator element 10 of the present embodiment is provided with an excitation electrode 15 as a driving electrode at the approximate center of one main surface of a quartz substrate formed in a rectangular flat plate shape. It is connected to an external connection electrode 16a provided near one end of the substrate. Similarly, the other main surface of the quartz substrate is provided with an excitation electrode (not shown) that is a counter electrode of the excitation electrode 15, and is provided outside the quartz substrate near one end. It is connected to an external connection electrode 16b provided in a different area from the connection electrode 16a.

  The electrodes such as the excitation electrode 15 and the external connection electrodes 16a and 16b are formed by, for example, nickel (Ni) by vapor deposition or sputtering after etching the quartz wafer serving as the base of the quartz substrate to form the external shape of the quartz crystal vibrating piece 10. Alternatively, it can be formed by using chromium (Cr) as a base layer, forming a metal film of, for example, gold (Au) thereon, and then patterning using photolithography.

  The vibrator package 20 includes a substantially rectangular flat plate-like first layer substrate 21, a substantially rectangular frame-shaped second layer substrate 22, a third layer substrate 23, and the like, which are sequentially stacked on the first layer substrate 21. A seal ring 28 is provided. With such a configuration, the vibrator package 20 is formed with a recess that opens to the second layer substrate 22 and the third layer substrate 23 side with the upper surface side of the first layer substrate 21 as a recessed bottom portion.

  A plurality of resonator element connection terminals 26a to which the crystal resonator element 10 is bonded are mounted on a shelf portion of the second layer substrate 22 that forms a step on the first layer substrate 21 that is a concave bottom portion of the recess of the resonator package 20. , 26b. Further, as shown in FIG. 4B, a plurality of external connection terminals 25a and 25b mounted on the external mounting board are provided on the lower surface side of the first layer substrate 21 which is the outer bottom surface of the vibrator package 20. It has been. Each of the resonator element connecting terminals 26a and 26b and the external connecting terminals 25a and 25b are connected to each other by an inner wiring such as a lead wiring or a through hole (not shown) formed on the first layer substrate 21. Has been.

  The first layer substrate 21, the second layer substrate 22, and the third layer substrate 23 of the vibrator package 20 are made of a ceramic insulating material or the like. In addition, the resonator element connecting terminals 26a and 26b and the external connecting terminals 25a and 25b provided in the resonator package 20, or the wiring pattern or the in-layer wiring pattern for connecting them are generally tungsten (W), molybdenum ( It is formed by screen-printing and firing a metal wiring material such as Mo) on a ceramic insulating material and then plating nickel (Ni), gold (Au) or the like thereon.

The crystal resonator element 10 includes external connection electrodes 16 a and 16 b provided near one end of the crystal resonator element 10 and a corresponding resonator element connection terminal 26 a provided on the second layer substrate 22 of the vibrator package 20. , 26b are aligned with each other by a bonding member such as a conductive adhesive 90, for example. As a result, the quartz crystal vibrating piece 10 is cantilevered with a gap so as not to contact the first layer substrate 21 with the opposite side of the external connection electrodes 16a and 16b joined to the vibrator package 20 as a free end. It is supported.
In general, the conductive adhesive 90 is made of a resin such as polyimide, silicon, or epoxy mixed with a silver (Ag) filler or a nickel (Ni) filler. Further, the joining member for joining the crystal vibrating piece 10 is not limited to the conductive adhesive 90, and other joining members such as solder can be used.

  A lid 29 is bonded on the third layer substrate 23 of the vibrator package 20 to which the crystal vibrating piece 10 is bonded. In this embodiment, a metal lid 29 is seam welded via a seal ring 28 formed by punching an iron-nickel (Fe-Ni) alloy or the like into a frame shape. Thereby, the quartz crystal vibrating piece 10 bonded in the recess of the vibrator package 20 is hermetically sealed.

[Constant temperature crystal oscillator]
Next, the constant temperature crystal oscillator 1 of this embodiment provided with the SMD type crystal resonator 30 described above will be described.
1 to 3, a thermostatic crystal oscillator 1 includes a circuit board 40 to which a crystal resonator 30 is bonded, an oscillation element 70 disposed on the circuit board 40, and a temperature-sensitive element 60 as a temperature control element. The temperature control circuit element 80 or the heating element 50 is accommodated in a container made of a base substrate 121 as a base and a lid. Here, the lid of the constant temperature crystal oscillator 1 of the present embodiment includes a metal cover body 129 as a metal layer provided on the base substrate 121 so as to surround the circuit board 40, and the metal cover body 129. It consists of a mold resin layer 95 as a covering resin layer.

  In the circuit board 40, a plurality of metal pins 5 a to 5 d that support the circuit board 40 in the constant temperature crystal oscillator 1 are inserted in the vicinity of a corner portion of a substantially rectangular base material in a plan view made of, for example, glass epoxy resin. Pin holes are provided. Further, on one main surface side of the circuit board 40, there are a vibrator connection terminal 43 corresponding to the external connection terminals 25a and 25b of the crystal vibrator 30 and a temperature sensitive element 60 arranged in the vicinity of the crystal vibrator 30. A temperature-sensitive element connection terminal (not shown) to be joined is provided. On the other main surface side of the circuit board 40, although not shown, a circuit element connection terminal to which circuit elements such as the heating element 50, the oscillation element 70, and the temperature control circuit element 80 are joined is provided. ing. These circuit element connection terminals, and the connection terminals such as the temperature sensing element connection terminals and the vibrator connection terminals 43 are connected to each other by inter-terminal wiring or intra-layer wiring formed in the base material. Circuit wiring is formed on the circuit board 40.

  A crystal resonator 30 is bonded to one main surface side of the circuit board 40. Specifically, the external connection terminals 25a and 25b provided on the outer bottom portion of the crystal resonator 30 and the corresponding resonator connection terminals 43 of the circuit board 40 are aligned, and solder or conductive adhesive (not shown) is arranged. It joins, measuring electrical connection with joining members, such as. A temperature sensitive element 60 is joined in the vicinity of the crystal unit 30. In addition, as the temperature sensing element 60, for example, an SMD type thermistor element made of a p-type semiconductor oxide or the like whose specific resistance changes relatively with increasing temperature can be used.

Circuit elements such as the heating element 50, the oscillation element 70, and the temperature control circuit element 80 are joined to the other main surface side of the circuit board 40. Specifically, each terminal portion (not shown) of each circuit element and the corresponding circuit element connection terminal (not shown) of the circuit board 40 described above are aligned, and solder or conductive material (not shown) is aligned. It joins, measuring electrical connection via joining members, such as an adhesive agent, or a bonding wire.
As the heating element 50, a chip resistance element having a relatively high resistance value or a heating element such as a chip type power transistor can be used.
As the oscillation element 70 and the temperature control circuit element 80, a so-called IC chip, which is a dedicated or general-purpose semiconductor circuit element in which an oscillation circuit or a temperature control circuit is formed, is used.

When the electric power controlled by the temperature control circuit element 80 is supplied to the heating element 50 in the physical part of the constant temperature crystal oscillator 1 including the circuit board 40 to which the circuit elements are bonded as described above, the joule of the heating element 50 is supplied. Heat is propagated to the crystal unit 30. Further, the temperature sensing element 60 directly detects the temperature of the circuit board 40 immediately below the crystal unit 30 and feeds back the temperature data to the temperature control circuit element 80, whereby the power supplied to the heating element 50 is reduced. Control.
In the present embodiment, the heating element 50 is disposed so as to overlap with the crystal resonator 30 bonded to the main surface on the opposite side of the circuit board 40 in plan view, and the heat generated by the heating element 50 is An example of conducting efficiently to the crystal unit 30 through the circuit board 40 will be described with reference to the drawings. The arrangement of the heating element 50 is not limited to this, and may be arranged so that the temperature in the vicinity of the crystal unit 30 can be kept constant by the heating element 50 at a practical level.

  The circuit board 40 to which circuit elements such as the crystal unit 30, the heating element 50, the temperature sensing element 60, the oscillation element 70, and the temperature control circuit element 80 are bonded is a metal pin provided in a plurality on the base substrate 121. It is supported by 5a to 5d. Specifically, the circuit board 40 is horizontally fixed in a state where the corresponding metal pins 5 a to 5 d erected on the base substrate 121 are inserted into pin holes provided in the vicinity of corner portions of the circuit board 40. ing.

  The plurality of metal pins 5 a to 5 d support the circuit board 40 to which various circuit elements are bonded and are used for electrical connection between the circuit board 40 and the base substrate 121. A plurality of mounting terminals 125a to 125d for joining the constant temperature crystal oscillator 1 and the external substrate are provided on the surface of the base substrate 121 that is the outer bottom surface of the constant temperature crystal oscillator 1 (FIG. 3). The mounting terminals 125 a to 125 d are connected to the corresponding metal pins 5 a to 5 d by intra-layer wiring such as routing wiring or through holes (not shown) provided on the base substrate 121. In the present embodiment, as shown in FIG. 3, the metal pin 5a and the mounting terminal 125a, the metal pin 5b and the mounting terminal 125b, the metal pin 5c and the mounting terminal 125c, and the metal pin 5d and the mounting terminal 125d are connected correspondingly. Has been.

  As described above, the lid is provided on the base substrate 121 including the circuit board 40 supported by the metal pins 5a to 5d so as to be covered over the circuit board 40 through a space. The lid body of the present embodiment includes a metal cover body 129 provided so as to cover the base substrate 121 on which the circuit board 40 is supported, and a mold resin layer 95 covering the outer peripheral surface of the metal cover body 129. .

Here, the base substrate 121 and the metal cover body 129 are inserted into holes (not shown) provided on the outer periphery of the base substrate 121 by, for example, claw portions (not shown) provided on the opening end surface of the metal cover body 129. Are joined.
Then, a mold resin layer 95 is formed by applying a mold resin with a dispenser or the like so as to cover the outer periphery of the metal cover body 129 and solidifying or molding the mold resin by a transfer molding method.

  Thereby, circuits such as the heating element 50, the temperature sensing element 60, the oscillation element 70, and the temperature control circuit element 80 joined to the circuit board 40 supported by the metal pins 5a to 5d erected from the base substrate 121. The constant temperature crystal oscillator 1 is configured in which the element and the crystal unit 30 are housed in a container made of a lid made of a metal cover 129 and a mold resin layer 95 and a base substrate 121.

According to the constant temperature crystal oscillator 1 of the first embodiment, the lid of the container forming the outer shape of the constant temperature crystal oscillator 1 is a metal cover body 129 conventionally used as a lid, and the metal cover body 129. Therefore, the heat capacity is higher than that in the case of using a container having only the metal cover body 129 as a lid. Thus, even when the metal cover body 129 is downsized as the constant temperature crystal oscillator 1 is downsized, the mold resin layer 95 exhibits a heat insulating effect, and an external temperature change causes physical changes such as the crystal unit 30. The influence on the part can be suppressed.
In addition, since the surface serving as the inner wall of the lid is constituted by the metal cover body 129, the inner surface of the metal cover body 129 has heat from the heating element 50, heat due to the operation of other circuit elements, etc. Is reflected to the inside of the container, so that the inside of the container can be efficiently heated and maintained at a constant temperature.
Therefore, it is possible to provide a small-sized constant temperature crystal oscillator 1 having an efficient and stable heating and heat insulation structure and having a highly accurate and stable oscillation characteristic.

(Second Embodiment)
In the constant temperature crystal oscillator 1 of the first embodiment, a lid having a configuration in which a metal cover 129 conventionally used as a lid is covered with a mold resin layer 95 as a resin layer is used. Not limited to this, it is possible to further reduce the size of the thermostatic crystal oscillator by using a lid with a metal coating as a metal layer on the inner wall surface of the body portion of the lid made of a resin layer. It is.

  FIG. 5 is a cross-sectional view schematically showing the constant temperature crystal oscillator of the second embodiment, and illustrates the same cross-sectional position as FIG. 2 describing the constant temperature crystal oscillator 1 of the first embodiment. is there. Of the configuration of the constant temperature crystal oscillator of the second embodiment, the configuration other than that the metal layer of the lid is made of a metal film is the same as that of the first embodiment, and thus the first embodiment. The same components as those in FIG.

  The constant temperature crystal oscillator 110 of the second embodiment shown in FIG. 5 includes a temperature control element including a crystal resonator 30, an oscillation element 70, a temperature sensitive element 60, a temperature control circuit element 80, and the like, and a heating element 50. Is bonded to a plurality of metal pins 5a to 5d (5c and 5d are not shown in the figure) erected on the base substrate 121. On the base substrate 121, a mold resin layer 95 is provided as a main body portion of the lid so as to surround the circuit board 40.

  The mold resin layer 95 can be formed using a resin molding die, for example, by a method of injection molding using an injection molding die. In the present embodiment, an example in which the mold resin layer 95 that becomes the main body portion of the lid body is formed by using the mold resin as in the first embodiment will be described. Not limited to this, other resin materials may be used.

A metal coating 229 as a metal layer is formed on the inner wall surface of the mold resin layer 95. The metal coating 229 can be formed by a sputtering method, a vapor deposition method, a plating method, or the like. The metal coating 229 may be any material as long as the metal coating 229 can function as a heat reflecting film. For example, various metals such as aluminum, nickel, or gold can be selected.
With the above-described configuration, circuit elements such as the heating element 50, the temperature sensitive element 60, the oscillation element 70, the temperature control circuit element 80, and the crystal vibration bonded to the circuit board 40 erected from the base substrate 121. A thermostat crystal oscillator 110 is formed in which a child 30 is housed in a container made of a base body 121 and a lid made of a mold resin layer 95 and a metal coating 229 formed on the inner wall surface of the mold resin layer 95. .

  According to the configuration of the constant-temperature crystal oscillator 110 of the second embodiment, compared to the constant-temperature crystal oscillator 1 of the first embodiment having a configuration in which the metal cover body 129 is used as the metal layer of the lid body, It is possible to provide a smaller constant temperature crystal oscillator 110 with a small number of points.

  The constant temperature crystal oscillators 1 and 110 described in the first and second embodiments can be implemented as the following modifications.

(Modification)
In the constant temperature crystal oscillators 1 and 110 of the first and second embodiments, the heating element 50 is disposed on the circuit board 40 to which the crystal resonator 30 and other circuit elements are bonded. Not limited to this, the heating element 50 may be arranged in contact with the metal layer of the lid.

  FIG. 6 is a cross-sectional view schematically showing the constant temperature crystal oscillator of the present modification, and the same cross section as FIG. 2 or FIG. 5 explaining the constant temperature crystal oscillators 1 and 110 of the first and second embodiments. The position is illustrated. Note that, among the configurations of the constant temperature crystal oscillator of the present modification, the configurations other than the arrangement of the heating elements are the same as those in the first and second embodiments. Therefore, the same configurations are denoted by the same reference numerals and described. Is omitted.

  The constant temperature crystal oscillator 210 of this modification shown in FIG. 6 includes a circuit board 40 to which a temperature control element composed of a crystal resonator 30, an oscillation element 70, a temperature sensitive element 60, a temperature control circuit element 80, and the like is bonded. The plurality of metal pins 5a to 5d (5c and 5d are not shown) are supported on the base substrate 121.

  As described above, on the base substrate 121 including the circuit board 40 supported by the metal pins 5a to 5d, the metal cover body 129 provided on the circuit board 40 through the space, and A lid made of a mold resin layer 95 covering the outer peripheral surface of the metal cover body 129 is disposed.

  In the constant-temperature crystal oscillator 210 of the present modification, the heating element 150 is arranged in contact with a part of the inner wall surface of the metal cover body 129 that becomes the inner wall surface of the lid. The heating element 150 has a feeling as a temperature control element joined to the circuit board 40 by a routing wiring, an intra-layer wiring (not shown) formed on the base substrate 121, or metal pins 5a, 5b (5c, 5d). The temperature element 60 and the temperature control circuit element 80 are connected. Note that the size and arrangement of the heating element 150 in FIG. 6 are for explaining an example, and have sufficient performance for making the constant temperature crystal oscillator 210 constant, and as a metal layer of the lid. The metal cover body 129 may be disposed so as to be in contact therewith, and is not limited to the illustrated one.

  According to the constant-temperature crystal oscillator 210 of the above modification, a container made of the lid made of the metal cover body 129 and the mold resin layer 95 and the base board 121 by the radiant heat generated by the metal cover body 129 heated by the heating element 150 It becomes possible to keep the whole inside of the container in a stable and constant temperature state. Therefore, it is possible to provide the constant temperature crystal oscillator 210 in which the frequency temperature characteristic is stabilized.

  The embodiment of the present invention made by the inventor has been specifically described above, but the present invention is not limited to the above-described embodiment, and various modifications are made without departing from the scope of the present invention. Is possible.

  For example, in the constant-temperature crystal oscillators 1, 110, and 210 of the above-described embodiments and modifications, circuits such as the crystal resonator 30, the temperature-sensitive element 60, the oscillation element 70, and the temperature control circuit element 80 that are bonded to the circuit board 40. The arrangement of the element, the heating element 50, and the like is an example of the arrangement, and can be changed as appropriate.

  In the embodiment and the modification, the example in which the metal cover 129 or the metal coating 229 as the metal layer of the lid is a metal layer formed on the entire inner wall of the lid has been described. Not limited to this, if the metal layer of the lid is formed on at least the main surface of the heating elements 50 and 150 on the inner wall surface of the lid, the heating elements 50 and 150 are generated. A large part of heat is reflected by the metal layer, and the inside of the container is kept constant.

In the above-described embodiment and the modification, the so-called surface-mount type constant temperature crystal oscillators 1, 110 and 210 having the mounting terminals 125a to 125d on the surface of the base substrate 121 which is the outer bottom portion of the container have been described. For example, the metal pins 5a to 5d may protrude through the outer bottom surface of the base substrate 121, and the protruding portions of the metal pins 5a to 5d may be used as connection terminals to the outside.
The constant temperature crystal oscillators 1, 110, 210 may be configured to hermetically seal the inside of the container formed of the base substrate 121 and the lid in a surface mount type or other type of configuration. A structure that is not hermetically sealed can also be selected. For example, when the inside of the container is hermetically sealed, various elements such as a heating element 50, a temperature sensing element 60, an oscillation element 70, and a temperature control circuit element 80 bonded to the circuit board 40, In addition, since the crystal unit 30 is shielded from the outside air, a constant temperature crystal oscillator having excellent aging characteristics and high reliability can be provided.

In the embodiment and the modification, the constant temperature crystal oscillators 1, 110 and 210 on which the crystal resonator 30 using the crystal resonator element 10 as the piezoelectric resonator element is mounted have been described. In addition to quartz, aluminum nitride (AlN), lithium niobate (LiNbO ₃ ), lithium tantalate (LiTaO ₃ ), lead zirconate titanate (PZT), lithium tetraborate (Li ₂ B ₄ O ₇₎ ) Or a piezoelectric vibrating piece made of a piezoelectric material formed by laminating a thin film piezoelectric material such as aluminum nitride or tantalum pentoxide (Ta ₂ O ₅ ) on a glass substrate. A constant temperature piezoelectric oscillator other than the oscillator can be provided.

  Further, the vibrator package 20 constituting the crystal vibrator 30 is not limited to the one having the laminated structure described in the above embodiment, and may be one integrated by machining or the like.

  DESCRIPTION OF SYMBOLS 1,110,210 ... Constant temperature crystal oscillator as a constant temperature type piezoelectric oscillator, 5a-5d ... Metal pin, 10 ... Crystal vibration piece as a piezoelectric vibration piece, 15 ... Excitation electrode, 16a, 16b ... External connection electrode, 20 ... Package for vibrator, 25a, 25b ... external connection terminal, 30 ... crystal vibrator as piezoelectric vibrator, 40 ... circuit board, 43 ... vibrator connection terminal, 50, 150 ... heating element, 60 ... temperature control element Temperature sensing element, 70 ... Oscillation element, 80 ... Temperature control circuit element, 90 ... Conductive adhesive, 95 ... Mold resin layer as resin layer, 121 ... Base substrate as base, 125a to 125d ... Mounting terminals 129: Metal cover body as a metal layer, 229: Metal film as a metal layer.

Claims (4)

A surface mount type piezoelectric vibrator in which a piezoelectric vibrating piece is housed in a package;
A circuit board to which the piezoelectric vibrator is bonded;
An oscillation element disposed on the circuit board and connected to the piezoelectric vibrator;
A temperature control element disposed on the circuit board;
The heating element connected to the temperature control element is a thermostatic piezoelectric oscillator housed in a container composed of a base and a lid,
The lid has a resin layer on a surface that is a part of the outer surface of the constant-temperature piezoelectric oscillator, and has a metal layer on at least the inner surface facing the main surface of the heating element. Constant temperature type piezoelectric oscillator. The constant temperature piezoelectric oscillator according to claim 1,
The thermostatic piezoelectric oscillator, wherein the lid includes a metal cover body as the metal layer and a mold resin layer as the resin layer covering the metal cover body. The constant temperature piezoelectric oscillator according to claim 1,
The constant temperature type piezoelectric oscillator, wherein the metal layer of the lid is made of a metal film formed on a surface of the resin layer. The constant temperature piezoelectric oscillator according to any one of claims 1 to 3,
The constant temperature piezoelectric oscillator, wherein the heating element is provided in contact with the metal layer.

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