JP2008136033A - Thermally conductive tray, tray unit, printed circuit board unit, and highly stable piezoelectric oscillator for highly stable piezoelectric oscillator - Google Patents

Abstract

A piezoelectric vibrator is fitted and arranged in an opening or notch provided in a printed circuit board, and a power transistor is juxtaposed in the lateral direction of the piezoelectric vibrator to reduce the thickness dimension of the entire oscillator. Furthermore, the present invention provides a heat-stable tray for a highly stable piezoelectric oscillator, a tray unit, a unit for a printed circuit board, and a highly stable piezoelectric oscillator that can improve the positional accuracy of both parts relative to the printed circuit board.
A heat conducting tray 21 for a highly stable piezoelectric oscillator, in which a piezoelectric vibrator body is hermetically sealed in a metal case, and two lead terminals projecting from the bottom of the piezoelectric vibrator body , And a power transistor mounting portion 23 for fixing a power transistor 40 that is juxtaposed in the lateral direction of the piezoelectric vibrator housing recess and heats the piezoelectric vibrator. And a metal plate provided with.
[Selection] Figure 1

Description

  The present invention relates to an improvement of a highly stable piezoelectric oscillator used as a frequency control device or the like, and particularly in a highly stable piezoelectric oscillator having a configuration in which a piezoelectric vibrator is heated by a power transistor and a heating temperature is controlled by a temperature control circuit. The present invention relates to a heat conducting tray, a tray unit, a printed circuit board unit, and a highly stable piezoelectric oscillator for a highly stable piezoelectric oscillator that can increase the positioning accuracy between the piezoelectric vibrator and the power transistor on the printed circuit board and can be thinned. .

  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 oven type piezoelectric oscillator that can output a highly stable frequency without being affected by external temperature changes has been conventionally used. Known from. Furthermore, in recent years, in these fields, various devices have been required to be small, light and portable, and accordingly, the thermostatic chamber type piezoelectric oscillator is required from the market to be small and light. It has been.

  In order to obtain a highly stable frequency, a conventional thermostatic oven type piezoelectric oscillator houses a piezoelectric vibrator in a recess of a thermostatic oven (even) such as a metal block having a large heat capacity, and further heats the metal block to a predetermined temperature with a heater. It was heated to. However, when a large metal block is used, the bulk of the entire oscillator increases, so that it has not been possible to satisfy the demand for reduction in size and weight. In addition, since the piezoelectric vibration element inside the piezoelectric vibrator is heated via the metal block, there is a problem that it takes a long time for the heat from the heater to reach the piezoelectric vibration element and reach the desired frequency. .

As a surface-mounting type high-stability piezoelectric oscillator that does not use a metal block, Japanese Patent Laid-Open No. 2002-223122 discloses a piezoelectric vibrator main body 101 in which a piezoelectric vibration element is hermetically sealed in a metal case 102 as shown in FIG. And two lead terminals 105 connected to the wiring pattern on the printed circuit board at the other end protruding outside and supporting the piezoelectric vibrating element by one end in the piezoelectric vibrator main body. 100 is mounted on the printed circuit board 110 in a lying state, and a power transistor 111 serving as a heater is interposed between the piezoelectric vibrator main body 101 and the printed circuit board surface, so that the piezoelectric vibration element inside the metal case 102 is provided. A configuration for heating is disclosed. The two lead terminals 105 extending from the piezoelectric vibrator main body have a configuration in which the lead terminals 105 extend in parallel with the substrate surface and are bent (curved) toward the wiring pattern on the substrate. Circuit components 112 such as an oscillation circuit component and a temperature control circuit component are mounted on the printed circuit board 110, and a space on the printed circuit board including the piezoelectric vibrator 100, the power transistor 111, the circuit components 112, and the like is formed in a metal oscillation case 113. The structure surrounded by is provided.
However, in this highly stable piezoelectric oscillator, the piezoelectric vibrator main body 101 is directly mounted on the power transistor 111 mounted on the upper surface of the printed circuit board in order to ensure sufficient thermal coupling. Is a dimension obtained by adding the thicknesses of the printed circuit board 110, the power transistor 111, and the piezoelectric vibrator 100, and there is a limit to the reduction in the overall height of the oscillator. Further, there is a problem that heat of the power transistor escapes to the printed circuit board 110 side.

Next, in the piezoelectric oscillator proposed by Japanese Patent Application No. 2006-198021, the power transistor is fitted in the notch provided on the printed circuit board, and then three lead terminals extending from the power transistor are provided at the notch periphery. Solder connected to the pad. Furthermore, the piezoelectric vibrator body is fixed in parallel to the lower surface of the printed circuit board by fixing the tips of two lead terminals bent in an L shape to a wiring pattern provided on the lower surface of the power transistor. The upper surface of the piezoelectric vibrator main body is bonded to the lower surface of the power transistor. By bringing the metal case upper surface of the piezoelectric vibrator into close contact with the lower surface of the power transistor fitted and disposed in the notch, the total height of the oscillator is reduced by the thickness of the printed circuit board.
However, even in this conventional example, since the power transistor and the piezoelectric vibrator are assembled in a vertical relationship, there is a limit to reducing the thickness.

In this conventional example, a printed circuit board on which a power transistor, a piezoelectric oscillator, and circuit components are mounted is supported in a hollow state by pins erected on a surface-mounted base printed circuit board. Since the space on the base printed board including the board is surrounded by the metal oscillator case, there is no room in the vertical direction in the metal oscillator case, and the printed board on which the power transistor, piezoelectric oscillator, and circuit components are mounted. It was necessary to increase the position accuracy in the height direction and the thickness dimension accuracy. For this reason, there was a possibility that productivity may fall. Specifically, if the mounting angle of the power transistor or piezoelectric vibrator that should be held in parallel with the printed circuit board surface is slightly inclined with respect to the printed circuit board surface, the internal height dimension is limited. The metal case composing the piezoelectric vibrator body comes into contact with the inner wall of the made metal oscillator case, and it becomes easy to dissipate heat, and it becomes difficult to control the frequency of the piezoelectric vibration element with high accuracy. As a result, the output frequency of the oscillator The problem is that it tends to fluctuate.
JP 2002-223122 A Japanese Patent Application No. 2006-198021

  As described above, in the conventional highly stable piezoelectric oscillator, by heating the power transistor as a heater in close contact with the upper surface or the lower surface of the piezoelectric vibrator supported in a posture parallel to the printed circuit board surface. The piezoelectric vibration element inside the piezoelectric vibrator main body was maintained at an appropriate temperature. For this reason, there is a limit in reducing the thickness of the entire oscillator. The same applies to the case where the power transistor is fitted in the notch provided on the printed circuit board. In this case, the mounting angle of the power transistor or the piezoelectric vibrator with respect to the printed circuit board is slightly increased in the vertical direction. If there is an inclination, there is a risk of causing heat dissipation due to contact between the piezoelectric vibrator and the metal oscillator case and a reduction in frequency characteristics of the oscillator due to the heat dissipation.

  The present invention has been made in view of the above, and by placing a piezoelectric vibrator in an opening or notch provided in a printed circuit board and arranging a power transistor in the lateral direction of the piezoelectric vibrator. A heat-stable tray for a highly stable piezoelectric oscillator, a tray unit, a unit for a printed circuit board, and a highly stable piezoelectric oscillator capable of reducing the thickness of the entire oscillator and further improving the positional accuracy of both parts relative to the printed circuit board It is intended to provide.

In order to solve the above-described problems, a heat conducting tray for a highly stable piezoelectric oscillator according to the present invention includes a piezoelectric vibrator main body in which a piezoelectric vibration element is hermetically sealed in a metal case, and two protruding from the bottom of the piezoelectric vibrator main body. A power transducer mounting section for fixing a piezoelectric vibrator housing recess for housing a piezoelectric vibrator having a lead terminal, and a power transistor for heating the piezoelectric vibrator that is juxtaposed in the lateral direction of the piezoelectric vibrator housing recess And a metal plate material provided with.
Conventionally, since the piezoelectric vibrator and the power transistor are arranged one above the other, there is a limit to reducing the height of the oscillator by the total thickness of both parts. According to the heat conducting tray of the present invention, not only the piezoelectric vibrator and the power transistor are disposed adjacent to each other in the lateral direction with good positioning properties, but both parts are positioned and supported by the heat conducting tray made of a metal material having good heat conductivity. As a result, it is possible to reliably realize a low profile and to effectively transfer heat from the power transistor to the piezoelectric vibrator and prevent heat radiation to the printed circuit board and other peripheral components. Moreover, the height position of both components with respect to the heat conducting tray can be determined with high accuracy.

The heat-stable tray unit for a highly stable piezoelectric oscillator according to the present invention is characterized in that the piezoelectric vibrator and the power transistor are respectively mounted on the heat-sink tray for the highly stable piezoelectric oscillator.
By mounting the piezoelectric vibrator and the power transistor on the heat conducting tray for the highly stable piezoelectric oscillator with good positioning, the positional accuracy in the height direction when incorporated in the oscillator can be increased. Further, it is possible to effectively conduct heat to the piezoelectric vibrator via the heat conducting tray.

In the heat conducting tray unit for a highly stable piezoelectric oscillator according to the present invention, the power transistor includes a heat radiating plate connected to a collector of a transistor chip on an upper surface thereof, and a solder is provided between the heat radiating plate and the piezoelectric vibrator. It is characterized by being connected.
A heat sink connected to the collector that generates the maximum amount of heat from the power transistor is exposed on the outer surface, and the heat sink and the piezoelectric vibrator are connected by soldering. In particular, the piezoelectric vibrator can be heated. Therefore, the frequency of the piezoelectric vibration element can be controlled with high accuracy, and the output frequency of the oscillator can be stabilized.

The heat-stable tray unit for a highly stable piezoelectric oscillator according to the present invention is characterized in that a metal piece is interposed and fixed between the piezoelectric vibrator and the heat dissipation plate of the power transistor.
The frequency of the piezoelectric vibration element can be controlled with high accuracy, and the output frequency of the oscillator can be stabilized.

In the heat conducting tray unit for a highly stable piezoelectric oscillator according to the present invention, the power transistor is mounted in a state where the collector side of the transistor chip faces downward and is in contact with the power transistor mounting portion of the heat conducting tray. The metal piece is inserted and fixed between the upper surface of the piezoelectric element and the piezoelectric vibrator.
The frequency of the piezoelectric vibration element can be controlled with high accuracy, and the output frequency of the oscillator can be stabilized.

  The printed circuit board unit for a highly stable piezoelectric oscillator according to the present invention includes the heat conductive tray unit, a printed circuit board that supports the heat conductive tray unit in a state where each lead terminal of the piezoelectric vibrator is connected to a wiring pattern, Circuit components mounted on a printed circuit board.

In the printed circuit board unit for a highly stable piezoelectric oscillator according to the present invention, the heat conduction tray unit is fitted and disposed in an opening formed in the surface of the printed circuit board or in a notch. It is characterized by that.
Since the piezoelectric vibrator and power transistor are not stacked one above the other, the height can be reduced, and the heat conducting tray unit is fitted and placed in the opening and notch provided in the printed circuit board. Thinning can be achieved.

The highly stable piezoelectric oscillator according to the present invention includes a base printed board on which the printed board unit is mounted, and a metal oscillator case surrounding the space on the base printed board including the printed board unit. Features.
By using the printed circuit board unit, productivity can be significantly increased.

Hereinafter, the present invention will be described in detail based on the embodiments shown in the drawings.
FIG. 1 is a front longitudinal sectional view showing a configuration of a highly stable crystal oscillator as a highly stable piezoelectric oscillator according to an embodiment of the present invention, and FIGS. 2A and 2B are perspective views of a main part (printed circuit board unit). FIG.
A highly stable crystal oscillator 1 includes a surface-mounted base printed circuit board (base printed circuit board) 2 and a printed circuit board unit 10 that is laid in parallel by pins 5 via a predetermined space between the upper surface of the base printed circuit board 2. And a metal oscillator case 50 fixed on the base printed circuit board 2 so as to surround a space on the base printed circuit board 2 including the printed circuit board unit 10.
The printed circuit board unit 10 includes a printed circuit board 11 and a heat conducting tray unit 20 that is disposed and fixed in an opening (or notch) 12 provided in the printed circuit board 11.

The heat conducting tray unit 20 includes a heat conducting tray 21 having a shape and size that can be fitted and arranged inside the opening 12 of the printed circuit board 11, and a crystal resonator (piezoelectric vibration) mounted on the heat conducting tray 21. Child) 30 and the power transistor 40.
As shown in the front view, plan view, and side view of FIGS. 3A, 3B, and 3C, the heat conducting tray 21 has a crystal resonator receiving recess that stores the crystal resonator 30 in a horizontal posture. (Piezoelectric vibrator housing recess) 22 and a power transistor mounting portion 23 on which the power transistor 40 is mounted side by side in the lateral direction of the crystal vibrator housing recess 22. Further, a locking piece 24 that is solder-fixed to the inner peripheral portion of the opening 12 of the printed circuit board protrudes from each side edge of the crystal resonator housing recess 22 and the power transistor mounting portion 23 as necessary. Has been established.

FIGS. 4A and 4B are an external perspective view and a front longitudinal sectional view showing the configuration of the crystal resonator. The crystal resonator 30 includes a crystal resonator element (piezoelectric resonator element) 33 in a metal case 32. A crystal resonator body 31 hermetically sealed, and two lead terminals 35 protruding from the bottom 34 of the metal case 32. The quartz resonator element 33 has a configuration in which excitation electrodes 33b are formed on both front and back surfaces of a quartz substrate 33a having a vibrating portion at the center, and lead patterns 33c are drawn from the excitation electrodes 33b toward opposite edges of the quartz substrate. I have.
The lead terminal 35 passes through a through hole provided in the bottom (base) 34 of the metal case and extends in and out of the metal case. The through hole and the lead terminal are insulated by a hermetic glass 36 and hermetically sealed. It has been stopped. An inner end portion of each lead terminal 35 is connected to each lead pattern 33 c of the crystal resonator element 33.

FIG. 5 is an external perspective view showing the configuration of a power transistor used as a heater. The power transistor 40 has an outer surface of a power transistor chip (not shown) covered with a mold resin 41 and three terminals extending from the transistor chip. 42 is configured to protrude from one end surface of the mold resin. Further, a heat radiating plate 43 in close contact with one surface (collector side) of the built-in transistor chip is exposed on the upper surface of the mold resin, and a heat radiating metal is disposed at the end of the heat radiating plate 43 opposite to the terminal 42. The projecting piece 44 is provided in a projecting manner. The protruding piece 44 constitutes a part of the heat radiating plate 43.
The heat conducting tray 21 made of a thin metal plate is processed with high accuracy in shape and size so that the heat conducting tray 21 is held in a posture parallel to the printed circuit board surface when fixed in the opening 12 of the printed circuit board.

By accommodating the crystal unit 30 in the crystal unit accommodating recess 22 and fixing it with an adhesive, solder, or the like, the crystal unit 30 is in a posture parallel to the printed circuit board surface and is at a height position with respect to the printed circuit board. Can be determined uniquely. Further, the power transistor is mounted on the power transistor mounting portion 23 and fixed, so that the power transistor has a posture parallel to the printed circuit board surface, and the height position relative to the printed circuit board can be uniquely determined. Further, the lateral positional relationship between the crystal unit 30 and the power transistor can be uniquely determined.
The heat conducting tray 21 has both the positioning means in the height direction and the lateral direction of the crystal unit 30 and the power transistor 40 with respect to the printed circuit board 11 and a function as a heat radiating plate. That is, the height position of each upper surface of the quartz crystal unit seated and fixed in the accommodation recess 22 and the power transistor 23 mounted on the mounting unit 23 is always constant.
The thin metal plate constituting the heat conducting tray 21 is manufactured using, for example, a nickel alloy, phosphor bronze, nickel plated aluminum plate, etc. that are compatible with solder.

As shown in FIG. 2A, in the state where the crystal unit 30 and the power transistor 40 are mounted on the required portions on the heat conducting tray 21 respectively, the two lead terminals 35 of the crystal unit 30 are connected to the periphery of the opening 12. The terminals 42 extending from the power transistor 40 are soldered to the pads on the periphery of the opening 12 while being soldered to the pads. Here, the central terminal of the three terminals 42 is a collector terminal, and this terminal and the locking piece 24 disposed below the terminal are soldered to the pad.
Further, in the present invention, the protruding piece 44 extending in the lateral direction from the heat sink 43 provided on the upper surface of the power transistor 40 is brought into contact with the metal case 32 of the crystal unit 30, and the metal case 32 and the protruding piece 44 (or The heat radiating plate 43 is connected and integrated by solder (heat transfer means) 45.

  According to the present invention, the metal case 32 of the crystal unit 30 is connected via the heat sink 43, the projecting piece 44, and the solder 45 that are in direct contact with the collector that is the heat generating part of the transistor chip disposed inside the power transistor 40. Not only a large amount of heat is conducted to the upper surface, but also the heat transmitted to the power transistor mounting portion 23 in contact with the lower surface of the power transistor 40 passes through the crystal unit housing recess 22 to the lower surface of the metal case 32. In order to be transmitted, the crystal unit inside the metal case is heated from both the upper and lower directions. For this reason, the heat generated from the power transistor can be effectively utilized for heating the crystal unit effectively and efficiently through the heat conducting tray 21.

Next, FIG. 6 is a front longitudinal sectional view showing another embodiment of the highly stable piezoelectric oscillator according to the present invention. The highly stable piezoelectric oscillator 1 is different from the piezoelectric oscillator according to the embodiment in that a crystal resonator and The metal piece (heat transfer means) 46 is interposed and fixed between the power transistor and the heat dissipation plate.
The metal piece 46 is fixed between the heat radiating plate 43 (projection piece 44) and the crystal unit 30 using solder or an adhesive having good thermal conductivity.
According to the present invention, with respect to the upper surface of the metal case 32 of the crystal resonator 30 via the heat sink 43 and the metal piece 46 which are in direct contact with the collector which is the heat generating part of the transistor chip disposed inside the power transistor 40. Thus, not only a large amount of heat is conducted, but also the heat transmitted to the power transistor mounting portion 23 in contact with the lower surface of the power transistor 40 is transmitted to the lower surface of the metal case 32 through the crystal resonator housing recess 22. Therefore, the crystal unit inside the metal case is heated from both the upper and lower directions. For this reason, the heat generated from the power transistor can be effectively utilized for heating the crystal unit effectively and efficiently through the heat conducting tray 21.

Next, FIG. 7 is a front longitudinal sectional view showing another embodiment of the highly stable piezoelectric oscillator of the present invention. The highly stable piezoelectric oscillator 1 is different from the piezoelectric oscillator according to each of the above embodiments in that it is a power transistor 40. Is mounted with the collector side (heat radiating plate side) of the transistor chip inside facing down and in contact with the power transistor mounting portion 23 of the heat conducting tray 21, and the upper surface of the power transistor (the side opposite to the collector) and the crystal The metal piece (heat transfer means) 46 is inserted and fixed between the vibrator 30 and the vibrator 30.
The metal piece 46 is fixed between the power transistor 40 and the crystal unit 30 using solder or an adhesive having good thermal conductivity.
According to the present invention, a large amount of heat is applied to the metal case 32 of the crystal unit 30 via the heat radiation plate 43 and the heat conducting tray 21 that are in direct contact with the collector that is the heat generating part of the transistor chip disposed inside the power transistor 40. Since not only heat is conducted but also heat from the upper surface of the power transistor 40 is transmitted to the upper surface of the metal case 32 via the metal piece 46, the crystal resonator inside the metal case is heated from both the upper and lower directions. Can do. For this reason, the heat generated from the power transistor can be effectively used for heating the crystal unit effectively and efficiently through the heat conducting tray.

  Although the crystal oscillator has been described in the above embodiment, the present invention can also be applied to other piezoelectric oscillators using a piezoelectric material other than quartz.

It is a front longitudinal cross-sectional view which shows the structure of the highly stable crystal oscillator as a highly stable piezoelectric oscillator which concerns on one Embodiment of this invention. (A) And (b) is a perspective view of a printed circuit board unit, and an exploded perspective view. (A) (b) And (c) is a front view, a top view, and a side view of a heat conducting tray. (A) And (b) is the external appearance perspective view which shows the structure of a crystal oscillator, and a front longitudinal cross-sectional view. It is an external appearance perspective view which shows the structure of the power transistor used as a heater. It is a front longitudinal cross-sectional view which shows other embodiment of the highly stable piezoelectric oscillator of this invention. It is a front longitudinal cross-sectional view which shows other embodiment of the highly stable piezoelectric oscillator of this invention. It is a longitudinal cross-sectional view which shows the structure of the highly stable piezoelectric oscillator which concerns on a prior art example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Highly stable piezoelectric oscillator, 2 ... Base printed circuit board, 4 ... Projection piece, 5 ... Pin, 10 ... Printed circuit board unit, 11 ... Printed circuit board, 12 ... Opening part, 20 ... Heat conduction tray unit, 21 ... Heat conduction tray, 22 DESCRIPTION OF REFERENCE SYMBOLS: Crystal resonator housing recess, 23 ... Power transistor, 23 ... Power transistor mounting portion, 24 ... Locking piece, 30 ... Piezoelectric resonator (crystal resonator), 31 ... Crystal resonator body, 32 ... Metal case, 33 DESCRIPTION OF SYMBOLS ... Quartz vibration element, 33a ... Quartz substrate, 33b ... Excitation electrode, 33c ... Lead pattern, 34 ... Bottom part, 35 ... Lead terminal, 36 ... Hermetic glass, 40 ... Power transistor, 41 ... Mold resin, 42 ... Terminal, 43 ... Radiation plate, 44 ... projecting piece, 45 ... solder, 46 ... metal piece, 50 ... metal oscillator case.

Claims (8)

A heat conducting tray for a highly stable piezoelectric oscillator,
A piezoelectric vibrator main body in which a piezoelectric vibration element is hermetically sealed in a metal case, and a piezoelectric vibrator housing recess for housing a piezoelectric vibrator having two lead terminals protruding from the bottom of the piezoelectric vibrator main body;
A power transistor mounting portion for fixing a power transistor which is juxtaposed in a lateral direction of the piezoelectric vibrator housing recess and heats the piezoelectric vibrator;
A heat-conducting tray for a highly stable piezoelectric oscillator, characterized by comprising a metal plate material provided with   A heat conducting tray unit for a highly stable piezoelectric oscillator, wherein the piezoelectric vibrator and the power transistor are respectively mounted on the heat conducting tray for a highly stable piezoelectric oscillator according to claim 1.   3. The high stability according to claim 2, wherein the power transistor includes a heat radiating plate connected to a collector of a transistor chip on an upper surface thereof, and the heat radiating plate and the piezoelectric vibrator are connected by solder. Heat conduction tray unit for piezoelectric oscillators.   The heat conducting tray unit for a highly stable piezoelectric oscillator according to claim 3, comprising a configuration in which a metal piece is interposed and fixed between the piezoelectric vibrator and a heat dissipation plate of the power transistor. The power transistor includes a heat dissipation plate connected to a collector of a transistor chip, and is mounted in a state in which the heat dissipation plate side faces downward and is in contact with the power transistor mounting portion of the heat conducting tray.
The heat conducting tray unit for a highly stable piezoelectric oscillator according to claim 2, comprising a configuration in which a metal piece is interposed and fixed between an upper surface of the power transistor and the piezoelectric vibrator.   6. The heat conducting tray unit according to claim 2, 3, 4, or 5, a printed circuit board that supports the heat conducting tray unit in a state where each lead terminal of the piezoelectric vibrator is connected to a wiring pattern, and mounted on the printed circuit board. And a printed circuit board unit for a highly stable piezoelectric oscillator.   7. The highly stable piezoelectric oscillator according to claim 6, wherein the heat conduction tray unit is reduced in height by being fitted and disposed in an opening formed in a surface of the printed circuit board or in a notch. Printed circuit board unit.   A highly stable system comprising: a base printed circuit board on which the printed circuit board unit according to claim 6 is mounted; and a metal oscillator case that surrounds a space on the base printed circuit board including the printed circuit board unit. Piezoelectric oscillator.

Images