JP2001274626A - Thin type highly stable piezoelectric oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin type highly stable piezoelectric oscillator adopting a configuration of controlling a heater temperature with a temperature control circuit that attains a nearly ultimate thin shape without the use of a thermostatic chamber made of a metallic block or the like causing a large-size and can satisfy various requirements such as stabilization of an oscillated frequency, low power consumption, improved assembling performance and cost reduction at the same time. SOLUTION: The thin type highly stable piezoelectric oscillator consists of a piezoelectric vibrator 21, a mother printed circuit board 22 having a notch to which the piezoelectric vibrator is fitted and fixing a lead terminal of the piezoelectric vibrator, a circuit component 25 mounted on the mother printed circuit board, two flexible printed circuit boards 27 that are placed along both front and rear sides of the piezoelectric vibrator and fixed to the mother printed circuit board, and heat resistors 26 each placed at a position opposed to both the front and rear sides of the piezoelectric vibrator and supported by each flexible printed circuit board.

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. Without using a constant-temperature bath such as a metal block, the thinning near the limit was achieved, and the oscillation frequency was stabilized.
The present invention relates to a thin and highly stable piezoelectric oscillator capable of simultaneously satisfying various demands of low power consumption, improved assemblability, and low cost.

[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, the size and weight of the thermostatic oven type piezoelectric oscillator have been required from the market. Have been.
That is, the height dimension of the conventional thermostatic oven type piezoelectric oscillator is usually 2
In some cases, the size is increased to a height of about 50 mm or more. However, in recent years, in response to the miniaturization of various devices, it has been strongly required that the height of the thermostat type piezoelectric oscillator be reduced to the same height as other large components. At present, among the thermostatic chamber type piezoelectric oscillators developed by the present applicant, the thinnest one is 9.2 mm in height, but the thermostatic chamber type piezoelectric oscillator which is thinner than this is on the market. Is required from. Meanwhile, in order to obtain a highly stable frequency, a conventional thermostatic oven type piezoelectric oscillator accommodates a piezoelectric vibrator in a recess of a thermostatic oven (open) such as a metal block having a large heat capacity, and further heats the metal block by a heater. Had been heated to the temperature. 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.

For example, a conventional thermostatic oven type piezoelectric oscillator shown in FIG. 5 includes a piezoelectric vibrator 1 such as a quartz vibrator and a piezoelectric vibrator 1.
Oscillator-side printed board 2 electrically connected to the lead terminals 1a of the piezoelectric vibrator 1 and the oscillator-side printed board 2
Metal block 4 housed inside with sideways
And a heater wire 5 wound around the outer surface of the metal block 4.
And a mother printed circuit board 7 electrically connected to and mechanically supported by the connecting member 6 protruding from the bottom surface of the metal block 4, and an oscillation circuit and the like mounted on a wiring pattern on the mother printed circuit board 7. A circuit component 8, a base 10 that penetrates and supports a lead member 9 that penetrates the mother printed board 7, and a case 11 that is assembled and fixed to the base 10 so as to surround a space on the base 10 that includes the above-described components. Etc. The lower part of the lead member 9 protruding downward from the base 10 is used when mounting on a printed board of a device body (not shown). A current is supplied from the lead member 9 to the circuit component 8 via the wiring pattern on the mother printed board 7, and further, a current is supplied to the piezoelectric vibrator 1 and the heater wire 5 via the connection member 6. .
However, in this type of thermostatic oven type piezoelectric oscillator,
Since the height of the metal block used is large and the metal block 4 is fixed in a state of floating above the upper surface of the mother printed board 7, the thickness T of the piezoelectric vibrator 1 is fixed.
The thickness T2 of the thermostatic chamber type piezoelectric oscillator main body is much larger than that of the first embodiment. Therefore, the height of the entire oscillator is increased.

Next, the thermostatic oven type piezoelectric oscillator shown in FIG. 6 is an improvement of the type shown in FIG. 5 to reduce the thickness. The difference between this oven type piezoelectric oscillator and that of FIG. A point where the lower surface of the metal block 4 is open, a point where the lower surface opening of the metal block is in contact with the mother printed circuit board 7, a lower surface of the piezoelectric vibrator 1 exposed from the lower surface opening and the mother print. Heater 1 between upper surface of substrate 7
2 and the circuit components 8 are connected to the mother printed circuit board 7.
And the like disposed on the lower surface of the. In this type of thermostatic oven type piezoelectric oscillator, the thickness T1 of the piezoelectric vibrator 1 can be made close to the thickness T2 of the thermostatic oven type piezoelectric oscillator main body. The limit is 9.2 mm, and it is impossible to keep it below that limit. Further, since the metal block 4 is still required to heat the piezoelectric vibrator as in the case of FIG. 5, this has been a major factor impeding the reduction in size and height. In addition, since the circuit components are mounted on the lower surface of the mother printed board, the circuit components come close to the base 10, and the amount of heat radiation increases, and the temperature change of the components increases. Had an adverse effect.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a piezoelectric oscillator having a configuration in which a heater temperature is controlled by a temperature control circuit, using a thermostat such as a metal block which causes an increase in size. A thin high-stability piezoelectric oscillator that can simultaneously satisfy various demands of stabilization of oscillation frequency, low power consumption, improvement of assemblability, and low cost while achieving the thinnest near the limit without the need. Is to do.

[0006]

In order to solve the above-mentioned problems, the present invention is directed to a piezoelectric vibrator having a piezoelectric vibrator main body and a lead terminal projecting from the piezoelectric vibrator main body;
A mother printed circuit board provided with a notch for fitting the piezoelectric vibrator main body and fixing the lead terminal; a circuit component mounted on the mother printed circuit board; It is characterized by comprising two flexible printed boards fixed to a printed board, and a heater resistor arranged at a position facing the front and back surfaces of the piezoelectric vibrator and held by each flexible printed board. According to a second aspect of the present invention, in the first aspect,
The heater resistor is connected and fixed on a surface of the flexible printed circuit board in advance.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings. FIG. 1 is a longitudinal sectional view of a thin high-stable piezoelectric oscillator according to an embodiment of the present invention, and FIG.
3 is a plan view of a state in which a piezoelectric vibrator is assembled to a mother printed board, and FIG. 4 is a configuration explanatory view of a flexible printed board. The thin high-stability piezoelectric oscillator includes a piezoelectric vibrator 21 such as a quartz vibrator, a mother printed board 22 that fits and supports the piezoelectric vibrating element 21 in a notch 23 while lying down, and a mother printed board 22.
For example, a lead member 24 made of a conductive material penetrated and fixed at a plurality of peripheral edges, and a circuit component 2 constituting an oscillation circuit and the like arranged at appropriate positions on the front and back surfaces of the mother printed circuit board 22
5, a heater resistor 26 attached to both upper and lower surfaces of the piezoelectric vibrator 21, and a flexible printed circuit board (for example, a flexible printed circuit board holding the heater resistor 26 on one surface and covering both front and back surfaces of the mother printed circuit board 22 including the piezoelectric vibrator 21). , Thickness 0.1mm)
27, a thermistor 28 fixed in place on the flexible printed circuit board 27 (near the heater resistor 26), and a lead member 2 protruding from the lower surface of the mother printed circuit board 22.
4 has a base 30 fixed by glass or the like in a state where the lower part of the base 4 is penetrated, and a case 31 surrounding the above components in a pair with the base 30. The base 30 and the case 31 constitute a metal package. Further, the circuit component 25 includes an oscillation circuit, a temperature control circuit, and the like.
The temperature control circuit controls the heat generation of the heater resistor 26 based on the temperature detected by the temperature detecting element such as the thermistor 28 to keep the temperature of the piezoelectric vibrating element 21 constant. The piezoelectric vibrator 21 includes a piezoelectric vibrator main body 21a and lead terminals 21b extending from the bottom surface of the main body 21. As a matter of course, the thickness of the mother printed board 22 is
Flexible printed circuit board 2 which is much thinner than
The thickness of 7 is smaller than the thickness of mother printed board 22.
The piezoelectric vibrator main body 21a fitted into the notch 23 of the mother printed board 22 is configured to be supported by the mother printed board 22 by being pressed against or fixed to the inner peripheral edge of the notch 23 by bonding. Alternatively, it may be configured to be supported by the flexible printed circuit board 27.

As shown in FIGS. 1, 2, and 3, the piezoelectric vibrator 21 has a mother printed circuit board 22 with a lead terminal 21b extending from a main body 21a of the piezoelectric vibrator 21 facing an inner edge 23a of a notch 23. The lead terminals 21b are fixed by being soldered to a wiring pattern (not shown) arranged along the inner edge 23a of the notch. The circuit component is arranged at an arbitrary position on the mother printed board surface excluding the notch 23. The flexible printed board 27 has a configuration in which a wiring pattern is formed on a flexible insulating substrate as is well known. As shown in FIG. 4, the flexible printed circuit board 27 has a configuration in which a heater resistor 26 is fixed on a wiring pattern (not shown) provided on a surface facing the upper or lower surface of the piezoelectric vibrator 21. A thermistor 28 is connected and fixed on the nearby wiring pattern. That is, the heater resistor 26 and the thermistor 28 are fixed on the surface of the flexible printed circuit board 27 in advance, and the piezoelectric vibrator 21 and the lead member 24 are arranged in a positional relationship as shown in FIG.
To the flexible printed circuit board 27.
A hole 27a is formed in the periphery of the flexible printed circuit board 27 so as to penetrate the upper part of the lead member 24 projecting upward from the periphery of the mother printed circuit board 22.
(Not shown) and this lead member 24 are connected by soldering. A conductive pad 27b (or a hole) is provided at an appropriate position in the surface of the flexible printed board 27, and the conductive pad 27b and a pad (not shown) on the mother printed board are electrically connected by a connecting member (not shown) or the like. By doing so, the mother printed circuit board 22
To the flexible printed circuit board 27. Thus, the thin high-stability piezoelectric oscillator of the present embodiment is
A notch 23 having a shape for fitting the piezoelectric vibrator 21 is formed in the mother printed board 22, and the lead terminals 21 b are connected to the mother printed board 22 with the piezoelectric vibrator 21 fitted in the notch 23. Since the wiring pattern is fixed by soldering, the mother printed board is fixed substantially at the center of the thickness of the piezoelectric vibrator main body 21a, and the height corresponding to the thickness of the mother printed board is reduced. Further, a heater resistor 26 is mounted on a flexible printed circuit board 27 having a size substantially equal to that of the mother printed circuit board 22 in advance, and the two flexible printed circuit boards are arranged so that the heater resistors 26 contact the front and back surfaces of the piezoelectric vibrator body 21a, respectively. 27 are attached so as to sandwich the piezoelectric vibrator body 21a from both sides. Therefore, the thickness T1 of the piezoelectric vibrator body 21a
And the thickness T2 of the oscillator body can be made substantially equal.

As a result, for example, H
When the C43U type is used, the thickness T2 of the oscillator main body can be set to 4.8 mm, the gap between the base 30 and the case 31 and the flexible printed circuit board,
The total thickness of this oscillator is 7.8 mm, which is a value obtained by adding 3 mm that is the sum of the thicknesses of the base 30 and the case 31. For example, when the HC54U type is used as the piezoelectric vibrator 21, the thickness T2 of the oscillator main body is set to 3.2.
mm, and a value obtained by adding each dimension of the gaps S1 and S2 between the base 30 and the case 31 and the flexible printed board and 3 mm which is a total thickness of the respective thicknesses of the base 30 and the case 31. Some 6.2 mm is the total thickness of this oscillator. As described above, according to the present invention, the thickness of the oscillator main body can be made as close as possible to the thickness of the piezoelectric vibrator main body 21a as an extremely thin, and as a result, the total thickness when housed in a package is limited to the conventional limit. The value could be suppressed to 9.2 mm or less. In addition to the elimination of the metal block, there is another advantage in that a conventionally required printed circuit board for an oscillator is not required. That is, the number of parts is small, and the assemblability is improved. In addition, since heating is performed by the heater resistance from both front and back surfaces of the piezoelectric vibrator, the heating capacity can be increased as compared with the conventional heating from one side, and the piezoelectric vibrator and circuit components are heated from both sides, Temperature characteristics are improved. As described above, in the present invention, without using a thermostat such as a metal block that causes an increase in size and height, the same thermal insulation effect as the thermostat is exhibited, thereby stabilizing the oscillation frequency and reducing power consumption. It is possible to achieve the thinning near the limit, and at the same time, satisfy various demands for improvement in assemblability and cost reduction.

[0010]

As described above, according to the present invention, in a piezoelectric oscillator having a configuration in which a heater temperature is controlled by a temperature control circuit, without using a constant temperature bath such as a metal block which causes an increase in size, And a thin, highly stable piezoelectric oscillator that can simultaneously satisfy various requirements of stabilization of oscillation frequency, low power consumption, improvement of assemblability, and low cost. . That is, according to the present invention, the piezoelectric vibrator is fitted into the notch of the mother printed board provided with the notch, and the lead terminals of the piezoelectric vibrator are fixed to the wiring pattern on the mother printed board. Circuit components are mounted on the top, and two printed circuit boards are attached to the front and back sides of the piezoelectric vibrator, and heater resistors are arranged at positions facing the front and back sides of the piezoelectric vibrator, and each flexible printed circuit board is used. Since the holding is performed, a constant temperature bath such as a metal block is not required at all, and the thickness can be reduced. That is, 0.1
The piezoelectric vibrator is surrounded by a thin flexible printed circuit board of about mm, and heater resistors fixed to this flexible printed circuit board are attached to both front and back surfaces of the piezoelectric vibrator. Thus, the heating capacity can be increased as compared with the conventional heating from one side, and the piezoelectric vibrator and the circuit components are heated from both sides, so that the temperature characteristics are improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a thin high-stability piezoelectric oscillator according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view on the right side of FIG.

FIG. 3 is a plan view showing a state in which a piezoelectric vibrator is mounted on a mother printed board.

FIG. 4 is a diagram illustrating the configuration of a flexible printed circuit board.

FIG. 5 is an explanatory view of a conventional example.

FIG. 6 is an explanatory view of another conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 21 Piezoelectric vibrator, 21b Lead terminal, 22 Mother printed board, 23 Notch, 24 Lead member, 25
Circuit components, 26 Heater resistance, 27 Flexible printed circuit board, 28 Thermistor, 30 Base, 31
Case,

Claims (2)

[Claims] 1. A piezoelectric vibrator having a piezoelectric vibrator main body and a lead terminal protruding from the piezoelectric vibrator main body, and a mother having a notch for fitting the piezoelectric vibrator main body and fixing the lead terminal. A printed circuit board, circuit components mounted on the mother printed circuit board, two flexible printed circuit boards attached to the front and back surfaces of the piezoelectric vibrator and fixed to the mother printed circuit board, and both front and back surfaces of the piezoelectric vibrator. A thin, high-stable piezoelectric oscillator, comprising: a heater resistor arranged at a position facing each other and held by each flexible printed circuit board. 2. The thin and highly stable piezoelectric oscillator according to claim 1, wherein the heater resistor is connected and fixed in advance on a surface of the flexible printed circuit board.