JP2000315916A - Piezoelectric oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric oscillator that prevents heat loss from a lead terminal led out from a piezoelectric vibrator main body so as to reduce the power consumption. SOLUTION: The piezoelectric oscillator is provided with a piezoelectric vibrator 23, an oscillation circuit 31 connected to a lead terminal 36 extended from a piezoelectric vibrator main body, a heater 24 that heats up the piezoelectric vibrator 23, a temperature control circuit 25 that controls the temperature of the heater, and a printed circuit board on which the components above are mounted, and the piezoelectric vibrator main body 40 reposes on the heater mounted on the printed circuit board. The printed circuit board consists of a 1st printed circuit board 21 and a 2nd printed circuit board 22 that is placed upright in crossing with an upper face of the 1st printed circuit board 21, the heater 24 is mounted at least at the upper face of the 1st printed circuit board 21, relating to the 2nd printed circuit board 22 a thermister 30 is mounted at its inner side face in a state that the 2nd printed circuit board 22 is placed upright on the upper face of the 1st printed circuit board 21, and the piezoelectric vibrator main body 40 is placed just close to the thermister 30 placed on the inner side face of the 2nd printed circuit board 22 by employing the lead terminal 36 of the piezoelectric vibrator 23 whose length is made as short as possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric oscillator used as a frequency control device or the like, and more particularly, to a piezoelectric oscillator having a structure in which a piezoelectric vibrator is heated by a heater and the temperature of the heater is controlled by a temperature control circuit. The present invention relates to a piezoelectric oscillator which prevents heat loss from a long lead terminal led out from a piezoelectric vibrator body to reduce power consumption.

[0002]

2. Description of the Related Art As a piezoelectric oscillator, such as a crystal oscillator, which is a frequency control device used in mobile communication equipment and transmission communication equipment, a thermostatic chamber capable of outputting a highly stable frequency without being affected by an external temperature change. 2. Description of the Related Art Conventional piezoelectric oscillators are known. Furthermore, in recent years, in these fields, various devices have been required to be small, lightweight and portable, and accordingly, a thermostatic oven type piezoelectric oscillator has also been required to be small and lightweight. I have. In order to obtain a stable frequency, a conventional thermostatic oven type piezoelectric oscillator accommodates a piezoelectric vibrator in a recess of a metal block having a large heat capacity, and further heats the metal block to a predetermined temperature by a heater. However, when a large metal block is used, the bulk of the oscillator as a whole increases, so that it has not been possible to satisfy the demand for reduction in size and weight. In addition, since the piezoelectric vibrating element inside the piezoelectric vibrator is heated via the metal block, there is a problem that it takes time for the heat from the heater to reach the quartz vibrating element and reach a desired frequency. From such a place, as shown in FIGS. 7A and 7B, the piezoelectric vibrator main body 11 is directly laid on the heater 2 mounted on the printed circuit board 1 in a state of lying down. Long lead terminal 13 led out horizontally
A piezoelectric oscillator has been developed which employs a configuration in which the substrate is bent downward in an L shape and connected to an oscillation circuit 4 on a printed circuit board. In this piezoelectric oscillator, since the metal cap 14 of the piezoelectric vibrator main body 11 is directly heated by the heater 2, it is possible to omit the use of a metal block which is bulky and requires time for heat conduction. Reference numeral 3 denotes a temperature control circuit for controlling the energization of the heater 2, 5 denotes a temperature detecting element (thermistor), 10 denotes a piezoelectric vibrator, and 12 denotes a conductor base.

[0003]

However, the piezoelectric vibrating element such as a quartz vibrating element located in the piezoelectric vibrator main body 11 has a lead made of a metal conductor rather than the influence of radiant heat from the metal cap 14 to which the heater 2 contacts. If the lead terminals 13 are long as shown in the figure, the metal cap 14 is heated by a heater to raise the internal crystal vibrating element to a desired temperature because the lead terminals 13 are more strongly affected by the heat conduction through the terminals 13. Even if heated, the lead terminals 13
The heat loss through the crystal resonator increases, and the frequency stability of the crystal resonator decreases. In order to solve this problem, it is necessary to increase the amount of heat generated by the heater, which leads to an increase in power consumption. However, in the conventional configuration, the printed circuit board 1
Since there is a limit in shortening the distance between the main body 11 and the quartz oscillator main body 11 supported on the heater 2, the lead terminals 13
There is a limit to the reduction of the length of the device, and it has been difficult to reduce the heat loss via the lead terminals. The problem to be solved by the present invention is to provide a piezoelectric oscillator having a configuration in which a piezoelectric vibrator is laid on a heater mounted on a printed circuit board to heat the piezoelectric vibrator. An object of the present invention is to provide a piezoelectric oscillator which prevents loss and reduces power consumption. In other words, by making the lead-out length as short as possible, heat loss from the lead terminal is minimized, and if necessary, the crystal vibrating element can be efficiently made by heat conduction through the lead terminal. The object is to cause heating.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a first aspect of the present invention is a piezoelectric vibrator having a piezoelectric vibrator main body and a lead terminal extending from the piezoelectric vibrator main body; An oscillation circuit connected thereto, a heater for heating the piezoelectric vibrator, a temperature control circuit for controlling the heater temperature,
And a printed board on which these are mounted, wherein the printed board comprises a first printed board, and a second printed board erected on the upper surface of the first printed board. The printed circuit board of No. 2 has a thermistor mounted on the inner surface thereof, and the lead terminals of the piezoelectric vibrator are made as short as possible so that the piezoelectric vibrator main body can be brought close to the thermistor on the inner surface of the second printed circuit board. It is characterized by being arranged. According to a second aspect of the present invention, in the piezoelectric vibrator, a conductor base, a lead terminal hermetically penetrating the conductor base, a piezoelectric vibration element supported by an upper part of the lead terminal, and a conductor base including the piezoelectric vibration element And a metal cap for hermetically sealing the space. The conductor base has a recess in the center thereof, and the thermistor is located in the recess sealed by the second printed circuit board surface. It is characterized by the following. The invention according to claim 3 is characterized in that a heater is arranged between the outer peripheral edge of the conductor base and the second printed circuit board. The invention according to claim 4 is characterized in that the heater is arranged close to a lead terminal. The invention of claim 5 is characterized in that a metal block having a U-shaped cross section surrounding the piezoelectric vibrator is fixed on the first printed circuit board. The invention of claim 6 is characterized in that a heater for heating at least the piezoelectric vibrator main body is arranged on the first printed circuit board.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings. FIGS. 1A and 1B are a front view and a plan view showing a state immediately before assembly of an example of a piezoelectric oscillator according to the present invention, and FIGS. 1C and 1D are front views showing a completed state of the piezoelectric oscillator. It is a figure and a top view. Also,
FIG. 2 is a perspective view showing the relationship between the piezoelectric vibrator and the second printed circuit board. The piezoelectric oscillator includes a horizontal first printed circuit board 21, a second printed circuit board 22 which is provided substantially vertically on the first printed circuit board, a piezoelectric vibrator 23,
The heater 24 mounted on the first printed circuit board 2, the temperature control circuit 25 mounted on the lower surface of the first printed circuit board 21, and the heater 24 mounted on the inner side surface (right side surface) of the second printed circuit board 22 Thermistor 30 and second printed circuit board 22
And an oscillation circuit 31 mounted on the outer side surface (left side surface). The oscillation circuit 31 is provided on the first printed circuit board 21.
It may be provided on the side. A characteristic configuration of the present invention is a piezoelectric oscillator in which a piezoelectric vibrator main body is laid on a heater 24 on a first printed circuit board 21 and supported on the first printed circuit board 21. By mounting a thermistor 30 on the inner surface of the piezoelectric element 22 and arranging the piezoelectric vibrator main body 40 as close to the thermistor 30 as possible, the lead terminals 3 drawn out from the piezoelectric vibrator main body 40
6 is made as short as possible, thereby reducing heat loss via the lead terminals. That is, the piezoelectric vibrator 23 supports a piezoelectric vibrating element (not shown in FIG. 1) at the ends of two lead terminals 36 that hermetically penetrate the conductor base 35,
Further, a configuration is provided in which a metal cap 37 for hermetically sealing the piezoelectric vibrating element with the conductor base 35 is fixed to the conductor base 35. The conductor base 35, the piezoelectric vibrating element, and the metal cap 37 constitute a piezoelectric vibrator main body 40.

[0006] As shown in FIG.
Are formed with two through-holes 22a, and each lead terminal 36 is inserted into these through-holes 22a and fixed by soldering, so that an electrical connection with the oscillation circuit 31 is made. Next, the assembling procedure will be described with reference to FIG. 1. As shown in FIGS. 1 (a), (b), (c), and (d), the piezoelectric vibrator 23 is inserted into the through hole 22a on the second printed circuit board 22. The lead cap 36 is inserted and fixed by soldering, and the metal cap 3 constituting the piezoelectric vibrator main body 40 is formed.
7 is laid on the heater 24. At this time, the heater 24 and the metal cap 37 are fixed if necessary. When the bottom surface of the conductor base 35 is flat as in the example of FIG. 1, the lead terminals 36 and the second printed circuit board 22 are placed in a state where the bottom surface of the conductor base 35 is in contact with the thermistor 30.
Is fixed. In this case, since the lead terminals 36 are exposed between the second printed circuit board 22 and the conductor base 35, heat loss occurs from the exposed lead terminal portions. Because it is much shorter than the terminals, the amount of heat loss that occurs is negligibly small.

Next, FIGS. 3A and 3B are an external view showing a structure of a piezoelectric vibrator used in a modified example of the present invention, and a longitudinal sectional view of a state mounted on a second printed circuit board. is there. The piezoelectric vibrator 23 supports a piezoelectric vibrating element 38 at the ends of two lead terminals 36 which hermetically penetrate a conductor base 35 having a concave portion 35a at the center, and further has a piezoelectric vibrator between it and the conductor base 35. A structure is provided in which a metal cap 37 for hermetically sealing the vibration element is fixed to the conductor base 35. As shown in FIG. 3B, the piezoelectric vibrator 2 is placed on the second printed circuit board 22.
3 when the outer peripheral edge 35b of the conductor base 35 is assembled.
Adheres on the second printed circuit board 22, and the thermistor 30
And the lead terminals 36 are sealed in the space between the second printed circuit board 22 and the conductor base 35,
There is no risk of heat radiation from the short lead terminal 36 into the atmosphere, and the frequency stability of the piezoelectric vibrating element 38 can be improved, and the amount of energy consumed by the heater can be minimized. Further, since the thermistor 30 is disposed close to the lead terminal 36 and the conductor base 35 in the closed space, the temperature can be measured at a position closer to the piezoelectric vibration element 38, and the heat in the heater temperature control using the temperature control circuit can be measured. Responsiveness can be improved, and frequency control with high follow-up to fluctuations in outside air can be performed.

FIG. 4 is a cross-sectional view showing a main part of another embodiment of the present invention (a modification of FIG. 3B). In this embodiment, a piezoelectric vibrator 23 is formed. Conductor base 3
5 is fixed on the second printed circuit board 22 via two second heaters (chip type) 40 mounted on the second printed circuit board 22. Therefore, the conductor base 35 and the metal cap 37 of the piezoelectric vibrator 23 can be efficiently heated together with the heating using the heater 24 on the first printed circuit board. Since the conductor base 35 and the lead terminals 36 are fixed via hermetic glass or the like, by heating the conductor base 35 with the heater 40, the internal piezoelectric vibration element 38 is efficiently heated via the lead terminals 36. can do. In this embodiment, since the heater 40 for heating the piezoelectric vibrator main body and the lead terminals is arranged on the second printed circuit board 22, the heater 24 on the first printed circuit board 21 can be omitted.

FIGS. 5 (a) and 5 (b) are a sectional view and an exploded perspective view, respectively, showing a modification of FIG. 4. The piezoelectric oscillator according to this embodiment has a second printed circuit board 22. It is characteristic that the two second heaters 40 provided above are configured so as to simultaneously contact (or approach) not only the outer peripheral portion 35b of the conductor base 35 but also each of the lead terminals 36. It is. With this configuration, not only the conductor base 35 and the metal cap 37 but also the lead terminals 36
Can be directly heated, so that the piezoelectric vibrating element 38 can be efficiently heated and controlled to a desired frequency. In this embodiment, since the heater 40 for heating the piezoelectric vibrator main body and the lead terminals is disposed on the second printed circuit board 22, the heater 24 on the first printed circuit board 21 is provided.
May be omitted. In each of the embodiments shown in FIGS. 4 and 5, since a gap is formed between the second printed circuit board and the outer peripheral edge of the conductor base, external cold air comes into contact with the lead terminals. Since the second heater is close to or in contact with the lead terminals, it is possible to perform sufficient heating and heat retention to compensate for the temperature drop due to external cold air. Finally, FIG. 6 shows an example in which the piezoelectric oscillator shown in each of the above embodiments is covered with a metal block as a thermostat so as to form a thermostat. The metal block 50 is formed in a U-shape using a metal having a good thermal conductivity and a large heat capacity, such as aluminum, for example. The metal block 50 includes the piezoelectric vibrator 23 and the thermistor 30 as illustrated. After being covered so as to cover, it is fixed on the first printed circuit board 21.

Since the heating of the piezoelectric vibrator 23 is performed directly by the heater 24 or the like, a metal block having a large heat capacity is not required, and the size can be reduced. Also, the oscillation circuit 31
Is located outside the metal block 50, so that the size of the thermostat can be avoided. Further, when the thermistor 30 is disposed in the metal block, a change in the operation of the oscillation circuit 31 due to a change in environmental temperature cannot be detected. By configuring so as to detect a change in the surrounding temperature, the temperature of the heater can be controlled based on the detected data, and as a result, the frequency stability can be ensured. In addition, the thermostatic oven type piezoelectric oscillator configured as described above is a case where high stability with respect to temperature is required, such as an oscillator used in a base station or the like, and does not hinder the shape from being slightly enlarged. It is suitable for the case. That is, it is possible to increase the heat capacity and improve the temperature stability by merely covering the metal block having a simple U-shape.

[0011]

As described above, according to the present invention, in a piezoelectric oscillator having a configuration in which a piezoelectric vibrator is laid on a heater mounted on a printed circuit board and heated, the piezoelectric vibrator is derived from the piezoelectric vibrator main body. Since the lead terminals are made as short as possible, it is possible to prevent an increase in heat loss from the lead terminals and reduce power consumption. In other words, the length of the lead terminal is set as short as possible, and the lead terminal is sealed in a closed space or heated by a heater to minimize heat loss from the lead terminal. Further, the quartz vibrating element can be efficiently heated by heating via the lead terminals. Note that, in the present invention, instead of providing a heater for lying down the piezoelectric vibrator on the first printed circuit board, the piezoelectric vibrator may be heated using a heater on another printed circuit board that is erected. In this case, the overall height of the piezoelectric oscillator can be reduced. In addition, it is possible to convert to a constant temperature bath type by putting a U-shaped metal block having a very simple configuration on the piezoelectric vibrator.

[Brief description of the drawings]

FIGS. 1 (a) and 1 (b) are a front view and a plan view showing an assembled straight state of an example of a piezoelectric oscillator according to the present invention, and FIGS.
(d) is the front view and top view which show the completion state of the assembly of the said piezoelectric oscillator.

FIG. 2 is a perspective view showing a relationship between a piezoelectric vibrator and a second printed circuit board.

FIGS. 3A and 3B are an external view showing a structure of a piezoelectric vibrator used in a modified example of the present invention, and a longitudinal sectional view of a state where the piezoelectric vibrator is mounted on a second printed circuit board.

FIG. 4 shows another embodiment of the present invention (a modification of FIG. 3B).
Sectional drawing which shows the principal part structure of FIG.

5 (a) and 5 (b) are a main part sectional view and an exploded perspective view showing a modification of FIG. 4;

FIGS. 6A and 6B are explanatory diagrams of a case where the piezoelectric oscillator of the present invention is configured as a thermostatic oven.

7 (a) and (b) are explanatory diagrams of a conventional example.

[Explanation of symbols]

Reference Signs List 21 first printed circuit board, 22 second printed circuit board, 23 piezoelectric vibrator, 24 heater, 25 temperature control circuit, 30 thermistor, 31 oscillation circuit, 35 conductor base, 35a recess, 35b outer peripheral edge, 36 lead terminal , 37 Metal cap, 38 Piezoelectric vibration element, 4
0 Piezoelectric vibrator body, 50 metal block

Claims (6)

[Claims] 1. A piezoelectric vibrator having a piezoelectric vibrator main body and a lead terminal extending from the piezoelectric vibrator main body, an oscillation circuit connected to the lead terminal, a heater for heating the piezoelectric vibrator, and a heater temperature. , And a printed circuit board on which these are mounted, wherein the printed circuit board is a first printed circuit board, and a second printed circuit board is provided on an upper surface of the first printed circuit board. The second printed circuit board is provided with a thermistor on the inner surface thereof, and the lead terminals of the piezoelectric vibrator are made as short as possible to form a piezoelectric vibrator main body. A piezoelectric oscillator which is disposed immediately adjacent to a thermistor on an inner surface of a substrate. 2. The piezoelectric vibrator includes: a conductor base; a lead terminal hermetically penetrating the conductor base; a piezoelectric vibration element supported by an upper portion of the lead terminal; and a space on the conductor base including the piezoelectric vibration element. And a metal cap that hermetically seals the conductor base. The conductor base has a recess in the center thereof, and the thermistor is located in the recess sealed by the second printed circuit board surface. The piezoelectric oscillator according to claim 1, wherein: 3. The piezoelectric oscillator according to claim 2, wherein a heater is arranged between an outer peripheral portion of the conductor base and the second printed circuit board. 4. The piezoelectric oscillator according to claim 3, wherein said heater is arranged close to a lead terminal. 5. The piezoelectric oscillator according to claim 1, wherein a metal block having a U-shaped cross section surrounding the piezoelectric vibrator is fixed on the first printed circuit board. 6. The piezoelectric oscillator according to claim 1, wherein a heater for heating at least the piezoelectric vibrator main body is disposed on the first printed circuit board.