JP2000013140A - Piezoelectric oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small sized highly stable crystal oscillator with low current consumption. SOLUTION: In the crystal oscillator where a crystal vibrator 8, an oscillation circuit 6 and a temperature control circuit 7 provided with a surface mounted small sized heater, a thermister and a power transistor are mounted on a printed circuit board 1, a wide area land pattern 3 to which a collector terminal of the power transistor(TR) 4 connects is provided on a 1st major side of the printed circuit board 1 and at least a power TR 4, a small sized heater 2 and thermisters 5, 5' are mounted on the 1st major side, and the crystal vibrator 8 and the land pattern 3 are connected by a resin 11 with a good heat conductivity and a metal 10 so as to attain the small sized heater 2 with a small heat capacity before mainly heating the crystal vibrator 8 and then low current consumption of the piezoelectric oscillator is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric oscillator,
In particular, the present invention relates to a piezoelectric oscillator having a high oscillation frequency.

[0002]

2. Description of the Related Art In the field of electric equipment such as a frequency counter and a satellite communication device used for maintenance of communication equipment of a mobile communication base station, these reference signals generally have a frequency stability of 1.times. Use a high-temperature oven-controlled crystal oscillator of about 10 ^-7 to 1 × 10 ^-10 . Furthermore, in these fields, miniaturization and weight reduction have been demanded in recent years.
There is also a high demand for a thermostat type crystal oscillator used for such a device to be smaller and lighter. However, in order to obtain a highly stable oscillation frequency, a conventional general thermostat type crystal oscillator stores a crystal oscillator in a recess of a metal block having a large heat capacity, and furthermore, the metal block is heated at a predetermined temperature. Heating is used, and there is a problem that the size of the oscillator is inevitable due to the large size of the metal block.

Therefore, a highly stable crystal oscillator that does not use a metal block has been proposed in order to achieve miniaturization. FIG. 3 shows a structural diagram of the highly stable crystal oscillator. FIG. 1A is a side view, and FIG. 1B is a top view. Printed circuit board 1 shown in FIG.
An oscillation circuit 102 and a temperature control circuit 103 are arranged on the lower surface of the printed circuit board 01, and six small surface-mounted small heaters 104, 104 ', 105, 10
5 ', 106, 106' are arranged at substantially equal intervals from each other. Further, a temperature sensor 111 is disposed on the printed circuit board 101 between the small heaters 106 and 106 ′,
The temperature sensor 111 is electrically connected to the temperature control circuit 103. The small heaters 104, 104 ', 1
05 and 105 ′ are both tightly fixed between the metal cap 108 of the crystal unit 107 and the printed circuit board 101. On the other hand, the small heaters 106 and 106 ′ are provided between the lead terminals 109 and 109 ′ of the crystal unit 107 and the printed circuit board 101 by metal pieces 110 and 110 ′.
And is tightly fixed via The small heater 104,
Each of 104 ′, 105, 105 ′, 106 and 106 ′ is controlled by the temperature control circuit 103 so that the temperature of the crystal unit 107 becomes constant. Further, the power transistor 112 constituting the temperature control circuit is disposed on the front side of the printed circuit board, and its collector is connected to the metal cap 10.
It is also used as an auxiliary heat source by being tightly fixed to the substrate 8.

The operation of the crystal oscillator having such a configuration will be described. When power is supplied to the crystal oscillator, the oscillation circuit 102 starts oscillating at a frequency based on the resonance frequency of the crystal oscillator 107. On the other hand, the temperature control circuit 103
Supplies power to the six small heaters so that the temperature detected by the temperature sensor 111 matches the set temperature. The small heaters 104, 104 ′, 105, 105 ′ heat the metal cap 108, and the radiant heat from the metal cap 108 heats the quartz plate in the cap. The small heaters 106, 106 'are connected to the lead terminals 109, 1
09 ′ is heated, and the quartz crystal plate is heated by the heat directly propagating from the lead terminals. By adopting such a configuration,
Even though each small heater has a small heat capacity, it uses a plurality of heaters and directly heats the crystal unit. It was possible to obtain a crystal oscillator that outputs a small and highly stable frequency.

[0005]

However, since the above-described crystal oscillator uses a plurality of small heaters, current consumption increases, and a portable device using the same has a short driving time by a battery. Problem had arisen.

[0006]

According to a first aspect of the present invention, there is provided a piezoelectric vibrator comprising: a piezoelectric vibrator;
In a piezoelectric oscillator in which an oscillation circuit, a heater, and a temperature control circuit for controlling a heating temperature of the heater are arranged on a printed circuit board, the temperature control circuit includes a temperature-sensitive element, a DC control transistor, Wherein a large area land pattern for connecting a collector terminal of the transistor is provided on a first main surface of the printed circuit board,
At least the transistor, the heater, and the temperature sensing element are arranged on a first main surface on the printed circuit board. The piezoelectric vibrator is arranged to cover the temperature sensing element and the heater, and The device and the land pattern are connected via a heat conductive member.

According to a second aspect of the present invention, in addition to the first aspect, the piezoelectric vibrator and the land pattern are connected via a metal plate.

According to a third aspect of the present invention, in addition to the first or second aspect, a resin is filled between the piezoelectric vibrator and the land pattern.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on illustrated embodiments. FIGS. 1A and 1B are an exploded structural view showing an embodiment of a crystal oscillator according to the present invention and a sectional structural view from a side. In this embodiment, as shown in FIG. 1, a small heater 2 of a surface mount type is mounted on the upper surface of a printed board 1, and one terminal of the small heater 2 has a large area provided on the printed board. It is connected to the land pattern 3. Further, a collector terminal of a power transistor 4 electrically connected to the small heater 2 is connected to the land pattern 3. As shown in FIG. 1A, a thermistor 5 and a thermistor 5 'are disposed at both sides of the small heater 2 at equal intervals as thermal elements. As shown in FIG.
And other electronic components constituting the temperature control circuit 7 and the like are arranged, for example, on the back surface of the printed circuit board. In addition, a metal support 9 is fitted into the crystal unit 8, and a terminal 10 protruding downward is provided on a part of the periphery of the support 9. The terminal 10 is connected to the land pattern 3 when the crystal unit 8 is mounted on the printed circuit board 1.
The terminal 10 and the land pattern 3 are fixed to each other by solder or the like having excellent thermal conductivity. At this time, the quartz oscillator 8 is arranged so as to be in close contact with the upper surface of the heater 2. Finally, a resin adhesive 11 having excellent thermal conductivity is filled between the vibrator 8 and the printed circuit board 1. The collector of the transistor is considered to be insulated from the ground.

FIG. 2 is a circuit diagram showing one embodiment of a temperature control circuit used in a crystal oscillator in which components are arranged as shown in FIG. In this figure, the thermistors TH1 and TH2 are denoted by 5 and 5 'in FIG. 1, the power transistor TR1 is denoted by 4 in FIG. 1, and the heater H1 connected to the collector of the power transistor TR1 is denoted by 2 in FIG. Each corresponds. With this configuration, the crystal oscillator 6 transfers heat from the small heater 2 directly from below the crystal oscillator 8 to the land pattern 3 by the small heater 2 and the collector of the power transistor 4. Is heated, and this heat is transmitted to the crystal oscillator 8 via the terminal 10 provided on the support 9 and the resin adhesive 11. Since the heat of the power transistor 4 is effectively used as an auxiliary heat source and the heat is transmitted to the crystal unit 8 by using the land pattern 3 having a large area and the resin adhesive 11, one small size having a small heat capacity is provided. It is possible to sufficiently heat the crystal unit 6 even with the heater. In addition, thermistors 5, 5 'are arranged on both sides of the crystal unit 8, and the number of temperature detection points is increased to enable highly sensitive temperature control.

[0011]

As described above, according to the first aspect of the present invention, the heat of the power transistor, which is an auxiliary heat source, is transmitted to a large area land pattern, and the heat transmitted to the land pattern is further subjected to piezoelectric vibration. By transmitting the heat to the piezoelectric vibrator, the heat of the power transistor is effectively transmitted to the piezoelectric vibrator, so that a small heater having a small heat capacity can be used as a main heating element for heating the piezoelectric vibrator, This produces an effect that the current consumption of the piezoelectric oscillator can be reduced.

According to a second aspect of the present invention, in addition to the effect of the first aspect, the heat of the power transistor transmitted to the land pattern is transmitted through a metal plate interposed between the land pattern and the piezoelectric vibrator. Since it is configured to be effectively transmitted to the piezoelectric vibrator, a heater for mainly heating the piezoelectric vibrator can have a small heat capacity, thereby reducing current consumption of the piezoelectric oscillator. This has the effect of becoming

According to a third aspect of the present invention, in addition to the first or second aspect, the heat of the power transistor transmitted to the land pattern is filled between the land pattern and the piezoelectric vibrator. Since the piezoelectric vibrator is configured to be effectively transmitted to the piezoelectric vibrator via the resin, the heater for mainly heating the piezoelectric vibrator can have a small heat capacity, thereby reducing the current consumption of the piezoelectric oscillator. It has the effect that it becomes possible.

[Brief description of the drawings]

FIG. 1 shows a configuration diagram of an embodiment of a crystal oscillator according to the present invention. FIG. 1A is an exploded view of an embodiment of a crystal oscillator according to the present invention. (B) is a side cross-sectional structural view of one embodiment of the crystal oscillator according to the present invention.

FIG. 2 is a circuit diagram of an embodiment of a temperature control circuit used in the present invention.

FIG. 3 shows a structural diagram of a conventional crystal oscillator. (A) is a side view of a conventional crystal oscillator. (B) shows a top view of a conventional crystal oscillator.

[Explanation of symbols]

1, 101 printed circuit board, 2 small heaters, 3 land patterns, 4, 112 power transistors, 5, 5 'thermistor, 6, 102 oscillation circuit, 7, 103 temperature control circuit,
8, 107 crystal oscillator, 9 support, 10 terminals, 11 resin, 104, 104 ', 105, 105', 106, 10
6 'small heater, 108 metal cap, 109, 109'
Terminal, 110, 110 'metal plate, 111 temperature sensor,

Claims (3)

[Claims] A piezoelectric oscillator in which a piezoelectric vibrator, an oscillation circuit, a heater, and a temperature control circuit for controlling a heating temperature of the heater are arranged on a printed circuit board.
The temperature control circuit includes a temperature-sensitive element and a DC control transistor, and has a large area land pattern for connecting a collector terminal of the transistor on a first main surface of the printed circuit board, At least the transistor, the heater, and the temperature sensing element are arranged on a first main surface on the printed circuit board. The piezoelectric vibrator is arranged to cover the temperature sensing element and the heater, and A piezoelectric oscillator, wherein an element and the land pattern are connected via a heat conducting member. 2. The piezoelectric oscillator according to claim 1, wherein the piezoelectric vibrator and the land pattern are connected via a metal plate. 3. The piezoelectric oscillator according to claim 1, wherein a resin is filled between the piezoelectric vibrator and the land pattern.