JP3997611B2 - Piezoelectric oscillator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a piezoelectric oscillator, and more particularly to a piezoelectric oscillator having a highly stable oscillation frequency.
[0002]
[Prior art]
In the field of electrical equipment such as frequency counters and satellite communication devices used for maintenance of communication facilities of mobile communication base stations, the frequency stability is generally 1 × 10 ⁻⁷ to 1 as a reference signal source. Use a highly stable thermostat crystal oscillator of about × 10 ^-10 .
Furthermore, in recent years, there is a demand for miniaturization and weight reduction in these fields, and there is a high demand for miniaturization and weight reduction for the thermostatic chamber crystal oscillator used therefor.
However, in order to obtain a high stable oscillation frequency, a conventional general thermostat crystal oscillator stores a crystal resonator in a recess of a metal block having a large heat capacity, and further, the metal block is placed at a predetermined temperature. There is a problem in that the size of the oscillator is unavoidable due to the large size of the metal block.
[0003]
Therefore, a highly stable crystal oscillator that does not use a metal block has been proposed in order to achieve miniaturization, and FIG. 3 shows a structural diagram of the highly stable crystal oscillator.
FIG. 4A is a side structural view, and FIG. 4B is a top structural view. An oscillation circuit 102 and a temperature control circuit 103 are arranged on the lower surface of the printed circuit board 101 shown in the figure, and six surface mount type small heaters 104, 104 ′, 105, 105 ′, 106 and 106 ′ are arranged at substantially equal intervals.
Further, a temperature sensor 111 is disposed on the printed circuit board 101 between the small heaters 106 and 106 ′, and the temperature sensor 111 is electrically connected to the temperature control circuit 103.
Each of the small heaters 104, 104 ′, 105, 105 ′ is closely fixed between the metal cap 108 of the crystal resonator 107 and the printed board 101.
On the other hand, the small heaters 106 and 106 ′ are tightly fixed between the lead terminals 109 and 109 ′ of the crystal resonator 107 and the printed circuit board 101 via metal pieces 110 and 110 ′.
The small heaters 104, 104 ′, 105, 105 ′, 106, 106 ′ are all controlled by the temperature control circuit 103 so that the crystal unit 107 has a constant temperature.
Further, the power transistor 112 constituting the temperature control circuit is disposed on the front side of the printed circuit board, and the collector thereof is also used as an auxiliary heat source by fixing the collector closely to the metal cap 108.
[0004]
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 resonator 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 quartz base plate in the cap is warmed by the radiant heat from the metal cap 108.
The small heaters 106 and 106 ′ heat the lead terminals 109 and 109 ′, and warm the crystal base plate by heat directly transmitted from the lead terminals.
By adopting such a configuration, even if each small heater has a small heat capacity, a plurality of these heaters are used, and the crystal resonator is directly heated. A crystal oscillator that can be heated and controlled to a temperature and outputs a small and highly stable frequency has been obtained.
[0005]
[Problems to be solved by the present invention]
However, since the crystal oscillator described above uses a plurality of small heaters, the current consumption increases, and there has been a problem that a portable device using this has a short drive time by a battery.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a first aspect of the present invention relates to a printed circuit board comprising a piezoelectric vibrator, an oscillation circuit, a heater, and a temperature control circuit for controlling the heating temperature of the heater. In the piezoelectric oscillator disposed above, the temperature control circuit includes a temperature sensing element and a DC control transistor, and a collector terminal of the transistor is connected to a first main surface of the printed circuit board. A land pattern having a large area is provided, and at least the transistor, the heater, and the temperature sensitive element are arranged on the first main surface on the printed circuit board, and the piezoelectric vibrator is connected to the temperature sensitive element and the heater. And the piezoelectric vibrator and the land pattern are connected via a heat conductive member.
[0007]
The invention according to claim 2 is characterized in that, in addition to the invention according to claim 1, the piezoelectric vibrator and the land pattern are connected via a metal plate.
[0008]
The invention described in claim 3 is characterized in that, in addition to the invention described in claim 1 or 2, a resin is filled between the piezoelectric vibrator and the land pattern.
[0009]
[Embodiments of the Invention]
Hereinafter, the present invention will be described in detail based on illustrated embodiments.
FIGS. 1A and 1B are an exploded configuration diagram showing an embodiment of a crystal oscillator according to the present invention and a sectional structure diagram from the side.
In this embodiment, as shown in the same figure, a surface mount type small heater 2 is mounted on the upper surface of the printed circuit board 1, and one terminal of the small heater 2 has a large area provided on the printed circuit board. It is connected to the land pattern 3.
Further, a collector terminal of a power transistor 4 that is electrically connected to the small heater 2 is connected to the land pattern 3.
As shown in FIG. 2A, a thermistor 5 and a thermistor 5 ′ are arranged as thermal elements at equal intervals on both sides of the small heater 2, respectively.
As shown in FIG. 5B, other electronic components that constitute the oscillation circuit 6, the temperature control circuit 7, and the like are disposed on the back surface of the printed circuit board, for example.
Further, a metal support 9 is fitted into the crystal resonator 8, and a terminal 10 protruding downward is provided at a part of the periphery of the support 9.
The terminal 10 is provided at a position corresponding to the land pattern 3 when the crystal resonator 8 is mounted on the printed circuit board 1. The terminal 10 is connected to the terminal 10 by solder having excellent thermal conductivity. The land pattern 3 is fixed.
At this time, the crystal unit 8 is disposed 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 board 1.
Note that the collector of the transistor is considered to be insulated from the ground.
[0010]
FIG. 2 is a circuit diagram showing an embodiment of a temperature control circuit used in the crystal oscillator in which the respective components are arranged as shown in FIG.
In the same figure, the thermistor TH1 and thermistor TH2 are shown in 5 and 5 'in FIG. 1, the power transistor TR1 is shown in 4 in FIG. 1, and the heater H1 connected to the collector of the power transistor TR1 is shown in 2 in FIG. Each corresponds.
With this configuration, the crystal resonator 6 directly transfers heat from the small heater 2 from the lower side of the crystal resonator 8, and the land pattern 3 is formed by the small heater 2 and the collector of the power transistor 4. Then, 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 heat is transferred to the crystal resonator 8 by using the land pattern 3 having a large area and the resin adhesive 11, it is one small size having a small heat capacity. Even with heating by a heater, the crystal resonator 6 can be sufficiently heated.
Further, the thermistors 5 and 5 ′ are arranged on both sides of the crystal resonator 8, and the temperature detection point is increased to enable highly sensitive temperature control.
[0011]
【The invention's effect】
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 the land pattern having a large area, and the heat transmitted to the land pattern is further transmitted to the piezoelectric vibrator. By configuring, the heat of the power transistor is effectively transferred to the piezoelectric vibrator, so that a small heater with a small heat capacity can be used as a main heating element for heating the piezoelectric vibrator. There is an effect that current consumption can be reduced.
[0012]
According to a second aspect of the present invention, in addition to the effect of the first aspect of the invention, the heat of the power transistor transmitted to the land pattern is effectively transmitted through a metal plate interposed between the land pattern and the piezoelectric vibrator. Since it is configured to be transmitted to the piezoelectric vibrator, the heater that mainly heats the piezoelectric vibrator can be made to have a small heat capacity, which makes it possible to reduce the current consumption of the piezoelectric oscillator. There is an effect.
[0013]
According to a third aspect of the invention, in addition to the first or second aspect of the invention, the heat of the power transistor transmitted to the land pattern is passed through a resin filled between the land pattern and the piezoelectric vibrator. Since it is configured so as to be effectively transmitted to the piezoelectric vibrator, it is possible to reduce the heat capacity of the heater that mainly heats the piezoelectric vibrator, and this makes it possible to reduce the current consumption of the piezoelectric oscillator. There is an effect.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an embodiment of a crystal oscillator according to the present invention.
(A) The exploded block diagram of one Example of the crystal oscillator based on this invention is shown.
(B) A side sectional structural view of an embodiment of a crystal oscillator according to the present invention is shown.
FIG. 2 is a circuit diagram of an embodiment of a temperature control circuit used in the present invention.
FIG. 3 is a structural diagram of a conventional crystal oscillator.
(A) The side surface structure figure of the conventional crystal oscillator is shown.
(B) A top structural view of a conventional crystal oscillator.
[Explanation of symbols]
1, 101 printed circuit board, 2 small heater, 3 land pattern, 4, 112 power transistor, 5, 5 'thermistor, 6, 102 oscillation circuit, 7, 103 temperature control circuit, 8, 107 crystal oscillator, 9 support, 10 Terminal, 11 resin, 104, 104 ′, 105, 105 ′, 106, 106 ′ small heater, 108 metal cap, 109, 109 ′ terminal, 110, 110 ′ metal plate, 111 temperature sensor,

Claims (3)

In a piezoelectric oscillator in which a piezoelectric vibrator, an oscillation circuit, a heater, and a temperature control circuit for controlling the heating temperature of the heater are arranged on a printed circuit board, the temperature control circuit includes a temperature sensing element and A large-area land pattern for connecting the collector terminal of the transistor to the first main surface of the printed circuit board, and a first main surface on the printed circuit board. At least the transistor, the heater, and the temperature sensing element are disposed on a surface, the piezoelectric vibrator is disposed so as to cover the temperature sensing element and the heater, and the piezoelectric vibrator and the land pattern A piezoelectric oscillator characterized in that the gap is connected through a heat conducting member.   The piezoelectric oscillator according to claim 1, wherein the piezoelectric vibrator and the land pattern are connected via a metal plate.   The piezoelectric oscillator according to claim 1 or 2, wherein a resin is filled between the piezoelectric vibrator and the land pattern.

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