JP2009302701A - Constant temperature type crystal device - Google Patents

Abstract

A constant temperature crystal device is provided for surface mounting in which the occurrence of stress during temperature change is prevented and the frequency deviation is maintained with high accuracy.
A vibrator crystal piece 2 housed in a container body 1 having a recess composed of a bottom wall and a frame wall, a heating resistor 4 and a vibrator housed in the container body 1 to heat the vibrator crystal piece 2 The surface sensitive resistor 3 for detecting the operating temperature of the crystal piece 2 for use and the cover 5 provided on the opening end face of the container body 1 are used for surface mounting to keep the operating temperature of the crystal piece 2 for vibrator constant. In the constant temperature type quartz crystal device, the vibrator crystal piece 2 faces the holding crystal plate 10 fixed in the horizontal direction on the inner bottom surface of the container body 1, and the extraction electrode extends from the excitation electrode of the vibrator crystal piece 2. The outer peripheral portion is fixed to the holding crystal plate 10.
[Selection] Figure 1

Description

  The present invention relates to a constant temperature crystal device for surface mounting, and more particularly to a constant temperature crystal device for surface mounting that suppresses stress distortion of a crystal piece for a vibrator due to a difference in thermal expansion coefficient and increases frequency stability. .

(Background of the Invention)
Constant-temperature crystal devices such as crystal oscillators maintain a constant operating temperature, so crystal oscillators using them have high frequency stability (for example, 1 to 0.5 ppm or less), such as base stations for optical communications. Used for communication equipment. In recent years, downsizing of these communication facilities has been permeated, and as a part of this, a constant temperature crystal device for surface mounting is required.

(An example of conventional technology, Patent Documents 1 and 2)
FIG. 11 is a diagram of a constant temperature crystal resonator (hereinafter, referred to as a constant temperature resonator) for surface mounting, illustrating a conventional example. FIG. 11 (a) is a cross-sectional view of the constant temperature resonator. FIG. 2B is a plan view of the crystal piece.

  The constant temperature type vibrator includes a container body 1, a vibrator crystal piece 2, a temperature sensitive resistor 3, a heating resistor 4, and a metal cover 5. The container body 1 is made of a laminated ceramic and has concave portions on both main surfaces. The concave portion on one main surface has an inner wall stepped portion provided with a crystal holding terminal 6, and the external terminal 7 is provided on the concave end surface of the other main surface.

  The vibrator crystal piece 2 is, for example, an SC cut of Y-rotation twice (see Patent Document 2), has excitation electrodes 8a on both main surfaces, and extends extraction electrodes 8b on both sides of one end in the length direction. Both sides of one end of the crystal piece from which the extraction electrode 8b extends are fixed to the crystal holding terminal 6 on the inner wall step by the conductive adhesive 9. The crystal holding terminal 6 is electrically connected to a crystal terminal in the external terminal 7.

  Both the temperature sensitive resistor 3 and the heat generating resistor 4 are formed of film resistance, and the temperature sensitive resistor 3 is formed on the bottom surface of the concave portion on one main surface, and the heat generating resistor 4 is formed on the bottom surface of the concave portion on the other main surface. And it electrically connects to the external terminal 7 for temperature resistors and heating resistors. The metal cover 5 is joined to the opening end surface of one main surface by, for example, seam welding, and the crystal piece 2 for vibrator is hermetically sealed.

  In such a case, the operating temperature of the crystal resonator (vibrator crystal piece 2) is kept constant by a temperature control circuit having a comparator and a power transistor (not shown) connected to the temperature sensitive element and the external terminal 7 for the heating resistor. To maintain. The operating temperature is on the high temperature side of the normal temperature (25 ° C.) or higher of the frequency temperature characteristic, and is usually set to an extreme temperature T ° C. at which the frequency change becomes gentle. In SC cut, the frequency temperature characteristic is a cubic curve with an inflection point of about 95 ° C., and the operating temperature (extreme temperature T ° C.) is about 80 ° C., which is a maximum value (FIG. 12).

  In addition, since the operating temperature of the crystal unit is set to the normal temperature or higher and higher than the ambient temperature, the temperature in the tank in the container body 1 can be controlled. For example, when the operating temperature is close to room temperature, when the ambient temperature rises above this, depending on the control circuit using the heating resistor 4, it cannot be lowered to near room temperature. Further, the maximum value is selected because the maximum value is lower than the minimum value and the power consumption is small.

  Then, the operating temperature of the crystal resonator is detected by a temperature sensitive resistor (eg, thermistor) 3, and the output of the power transistor is controlled based on the temperature difference signal from the comparator with the extreme temperature T ° C. The heating resistor 4 is supplied with electric power at the operating temperature (extreme temperature T ° C.). As a result, the crystal resonator maintains the operating temperature at the extreme temperature T ° C., and maintains the oscillation frequency of an oscillation circuit (not shown) connected to the crystal terminal with high accuracy regardless of the change in the ambient temperature.

Normally, the oscillation frequency at the extreme temperature (T ° C.) that is the operating temperature is the nominal frequency f 0, the temperature inside the tank is allowed to be ± α °, for example, from the extreme temperature T ° C., and the frequency deviation standard is f 0 ± β ppm. And The temperature control circuit and the oscillation circuit are accommodated in the container body 1 separately from the container body 1 or together with the vibrator crystal piece 2. Thus, for example, miniaturization is promoted as compared with a constant temperature type vibrator using a heater wire.
JP 2004-343339 A JP 2007-201858 A JP 2008-11335 A (FIG. 7, SC cut frequency temperature characteristics) Japanese Patent No. 3017746 Japanese Patent No. 3017750 FCS Vol. su-31 No.1 January 1984 p11〜 (Simplified Expressions for the stress-Frequency Coefficients of Quartz Plates)

(Problems of conventional technology)
However, although the constant temperature type vibrator having the above-described configuration is a constant temperature type with a constant operating temperature, the temperature in the tank changes within an allowable temperature ± α ° with respect to the extreme temperature T ° C. On the other hand, the vibrator crystal piece 2 is fixed to the inner wall step portion of the container main body 1, and the vibrator crystal piece 2 and the container main body 1 have different thermal expansion coefficients with respect to temperature. Thereby, based on the difference in thermal expansion coefficient from the container body 1 within the allowable temperature ± α °, stress distortion occurs in the vibrator crystal piece 2 and the vibration frequency changes.

  Therefore, when the temperature in the bath changes during the operation of the constant temperature type vibrator, a frequency change occurs due to the frequency temperature characteristics of the crystal vibrator itself and the stress strain based on the difference in thermal expansion coefficient. In this case, in the SC cut, the extreme temperature T ° C. as the operating temperature is set to the maximum value (80 ° C.). Accordingly, when the operating temperature rises or falls from the extreme temperature T ° C., the vibration frequency drops from the nominal frequency f 0 at the extreme temperature (T ° C.) in any case.

  Then, when the temperature rises from the extreme temperature T ° C. and when the temperature falls, the action due to stress strain at the time of temperature change is also reversed, and the frequency change is in the opposite direction. For example, if the frequency decreases when the temperature rises from the extreme temperature T ° C., the frequency increases when the temperature drops from the extreme temperature T ° C.

  Therefore, in this case, due to the frequency temperature characteristics of the crystal resonator (SC cut), the temperature in the tank rises from the extreme temperature T (80 ° C.) and rises, for example, + α ° of the allowable value, and is within the frequency deviation standard. Even in the case of −β ppm, a frequency drop due to stress strain is added. Therefore, when frequency change due to frequency temperature characteristics and stress strain is taken into consideration, the frequency deviation standard is not satisfied.

  However, even if the temperature falls below the allowable value of -α ° from the extreme temperature T (80 ° C) and falls outside the frequency deviation standard of -βppm, the frequency increase due to stress strain is added. The deviation standard can be satisfied. However, as described above, the frequency deviation standard at the time of temperature rise cannot be satisfied.

  As a result, even if the operating temperature of the crystal resonator is, for example, the extreme temperature t ° ± α ° C., and the frequency deviation due to the frequency temperature characteristic is within 1 ppm, the frequency variation due to stress strain is added, so the frequency deviation is 1 ppm. There was a problem that exceeded. In addition to the frequency change due to the stress strain due to the difference in thermal expansion coefficient, the frequency also changes due to a change in the holding system including a change in the state of the conductive adhesive 9, for example.

  From this, it is conceivable to design the operating temperature of the crystal resonator as an extreme temperature t ° ± α ′ (<α) in consideration of the frequency change due to stress strain. However, in this case, the accuracy of the constant temperature structure including the temperature control circuit is required, which makes designing difficult. In particular, when the conductive adhesive 9 for fixing the crystal unit 2 for vibrator is made of, for example, polyimide, and has a high hardness, the amount of change in frequency due to stress increases, so the problem becomes significant.

  For example, the conductive adhesive 9 may be replaced by a silicone system instead of a polyimide system to relieve stress. However, in this case, the thermosetting temperature is also low, and the released gas at the time of curing adheres to the vibrator crystal piece 2 to deteriorate the vibration characteristics. On the other hand, the polyimide system has a high thermosetting temperature, hardly emits gas during curing, and does not adhere to the vibrator crystal piece 2, so that the vibration characteristics are favorably maintained.

(Object of invention)
An object of the present invention is to provide a constant temperature crystal device for surface mounting that prevents the generation of stress at the time of temperature change and maintains the frequency deviation with high accuracy to facilitate the design.

  According to the present invention, as shown in the claims (Claim 1), a container main body having a recess composed of a bottom wall and a frame wall on at least one main surface and containing a crystal piece for a vibrator in the recess; A heating resistor housed in the container main body for heating the vibrator crystal piece, a temperature sensitive resistor for detecting an operating temperature of the vibrator crystal piece, and an opening end face of one main surface of the container main body. A constant temperature crystal device for surface mounting that maintains a constant operating temperature of the vibrator crystal piece, and the vibrator crystal piece is fixed to the inner bottom surface of the container body in a horizontal direction. An outer peripheral portion facing the holding crystal plate and extending from the excitation electrode of the vibrator crystal piece is fixed to the holding crystal plate, and the inner surface of the container main body of the holding crystal plate Position and the vibration The structure different from the fixed position relative to the holding quartz plate child for the crystal element.

  With such a configuration, the crystal device for surface mounting is made to be a constant temperature type, and the crystal piece for vibrator is fixed (held) to the holding crystal plate. In this case, the thermal expansion coefficient with respect to the temperature of the vibrator crystal piece and the holding crystal plate is basically the same because they are the same crystal. The fixing position of the holding crystal plate to the inner surface is different from the fixing position of the vibrator crystal piece to the holding crystal plate. Therefore, even if a stress distortion occurs between the fixing parts due to the difference in thermal expansion coefficient between the holding crystal plate and the container main body, the difference between the fixing positions of the holding crystal plate and the vibrator crystal piece between the fixing positions is different. The stress strain at is relaxed. Therefore, even if the temperature in the tank of the container main body changes, the frequency change of the quartz crystal piece for vibrator due to the stress strain is prevented.

  From this, the frequency change due to the change in the temperature of the vessel body is basically only the change based on the frequency-temperature characteristics of the crystal resonator. Therefore, it is not necessary to consider the frequency change due to the stress strain based on the difference in thermal expansion coefficient of the quartz crystal piece for the vibrator, so that the design of the constant temperature structure is facilitated and the frequency deviation is maintained with high accuracy.

(Embodiment section)
According to a second aspect of the present invention, in the first aspect, the operating temperature of the vibrator crystal piece is an extreme temperature at which the frequency temperature characteristic has a maximum value or a minimum value equal to or higher than room temperature. This clarifies the operating temperature in the frequency temperature characteristics of the crystal unit for vibrator. Then, it is possible to eliminate a change in frequency of the quartz crystal piece for vibrators in opposite directions due to stress strain when the temperature in the bath rises or falls below the extreme temperature.

  However, even if the operating temperature of the quartz crystal piece for vibrator is a temperature between the minimum value and the maximum value above room temperature as in the case of SC cut, for example, it is not necessary to consider stress strain as described above. Basically applicable. In this case, the frequency change with respect to the temperature change can be reduced by setting the inflection point temperature as the operating temperature, for example, as the cutting angle between the maximum value and the minimum value, which is, for example, 0 temperature coefficient.

  In the third aspect of the present invention, in the second aspect, the quartz crystal piece for vibrator is an SC cut having a maximum value above the room temperature of the frequency temperature characteristic or an AT cut having a minimum value above the room temperature of the frequency temperature characteristic. As a result, the crystal unit for vibrator according to claim 2 is made concrete and a highly stable oscillation frequency for communication can be obtained. In addition to the SC cut, it is needless to say that it can be applied to a so-called two-turn Y-cut having a maximum value above room temperature, for example, an IT cut.

  In the fourth aspect of the present invention, in the first aspect, the vibrator crystal piece is fixed to the holding crystal plate with a polyimide-based conductive adhesive. Thereby, for example, compared to a silicone type made flexible, the generation of organic gas is prevented and vibration characteristics are maintained well, and stress distortion due to the hardness of the polyimide-based adhesive is alleviated. The effect of 1 is remarkable.

  According to claim 5 (corresponding to the first embodiment), in claim 1, the extraction electrode extends to both sides of one end portion of the vibrator crystal piece, and both ends of the end portion of the crystal piece for vibrator are the holding crystal. The holding quartz plate is fixed to both sides of one end of the plate, and the center of both ends in the length direction is fixed to the inner surface of the container body. As a result, both sides of one end of the crystal piece for vibrator become free ends together with the holding crystal plate, so that stress distortion does not occur.

  In claim 6 (corresponding to the second embodiment), in claim 1, the extraction electrode extends to both sides of one end of the vibrator crystal piece, and both ends of the crystal part for vibrator are on the holding crystal. The holding quartz plate is fixed to both sides of one end of the plate, and both end sides in the width direction which are closer to the center than both sides of the one end are fixed to the inner surface of the container body.

  According to this, the fixing position of the vibrator crystal piece to the holding crystal plate and the fixing position to the inner surface of the holding crystal plate are different in the length direction. Therefore, even if stress strain is generated in the width direction near the center of the holding crystal plate, the stress strain on both sides of the one end portion separated from the center is reduced. Therefore, both sides of the one end portion where the vibrator crystal piece and the holding crystal plate are fixed are free ends, so that no stress distortion occurs.

  According to claim 7 (corresponding to the fourth embodiment), in claim 1, the extraction electrode extends to both ends of the vibrator crystal piece, and both ends of the vibrator crystal piece are formed on the holding crystal plate. The holding crystal plate is fixed to both end portions, and both end portions of the holding crystal plate are fixed to the inner surface of the container main body, the fixing positions of the both end portions of the vibrator crystal piece to the holding crystal plate, and the holding crystal plate The fixing positions of both end portions with respect to the inner surface are different in the width direction.

  In this case, the fixing position of the vibrator crystal piece to the holding crystal plate and the fixing position to the inner surface of the holding crystal plate are different in the width direction. Therefore, similarly to the sixth aspect, since both ends where the crystal unit for vibrator and the crystal plate for holding are fixed become free ends, stress distortion does not occur.

  The container body according to claim 1 is provided with at least a temperature control circuit element or an oscillation circuit element. Thereby, a crystal device with increased added value can be obtained.

(First embodiment)
FIG. 1 is a view for explaining a first embodiment of the present invention. FIG. 1 (a) is a cross-sectional view of a constant temperature type vibrator, FIG. 1 (b) is a plan view of a container body, and FIG. FIG. In addition, the same number is attached | subjected to the same part as a prior art example, and the description is simplified or abbreviate | omitted.

  As described above, the constant temperature type vibrator is provided with the temperature sensitive resistor 3 on the bottom surface of the concave portion, which is one main surface of the container body 1 made of multilayer ceramic, and the heating resistor 4 is provided on the bottom surface of the concave portion of the other main surface. Both the temperature sensitive resistor 3 and the heating resistor 4 are formed by printing and baking as film resistance. The resonator crystal piece 2 is SC-cut, and the extreme temperature T (80 ° C.) that is the maximum value of the frequency temperature characteristic is the operating temperature. An opening end face of one main surface of the container main body 11 is covered with a metal cover 5 so that the vibrator crystal piece 2 is hermetically sealed.

  In this embodiment, the resonator crystal piece 2 faces the holding crystal plate 10, and both ends of one end of the extraction electrode 8 b extending from the excitation electrode 8 a are fixed by the conductive adhesive 9. The holding crystal plate 10 is, for example, an SC cut having the same cutting angle as that of the vibrator crystal piece 2. And the crystal holding | maintenance crystal | crystallization piece 2 is fixed, and it has the crystal | crystallization holding | maintenance terminal 6 which electrically connects on the both ends of the one end part of one main surface. The crystal holding terminal 6 extends to the other main surface through the outer surface by a wiring path (not shown), and is electrically connected to the conduction terminal 11 at the center of both ends. For example, a protective film made of coating or the like is provided on the wiring path to prevent disconnection or the like during transfer by vacuum suction, for example.

  Correspondingly, the conductive terminal 11 is fixed to the circuit terminal 12 at the center of both ends provided on the inner bottom surface of the container body 1 by a conductive adhesive 9 (not shown) and is electrically connected. In short, the center of both ends of the holding crystal plate is fixed to the center of both ends of the inner wall step which is the inner surface of the container main body 1, and the vibrator crystal piece 2 is fixed as both sides of one end of the holding crystal plate.

  All the conductive adhesives 9 are made of polyimide which generates less organic gas. Then, the external terminal (crystal terminal) 7 of the vibrator crystal piece 2 provided on the outer bottom surface of the container body 1 is connected to the oscillation circuit, and the temperature sensitive resistor 3 and the external terminal 7 of the heating resistor 4 are connected to the temperature control circuit. As a result, the operating temperature of the constant temperature oscillator is controlled within the extreme temperature T (80 ° C.) ± α ° as described above, and the frequency deviation standard of the oscillation frequency is set to f 0 ± β ppm.

  With such a configuration, both ends of one end of the crystal piece 2 for vibrator are fixed to the holding crystal plate 10 having the same cutting angle and the same thermal expansion coefficient. Therefore, even when the vibrator crystal piece 2 is different from the thermal expansion coefficient of the container main body 1, stress distortion due to the difference in thermal expansion coefficient can be basically suppressed.

  However, the holding crystal plate 10 has an SC cut with the same cutting angle as that of the crystal piece 2 for vibrator, but basically, a quartz crystal can be applied because it has almost the same thermal expansion coefficient. In particular, if the holding crystal plate 10 is a cutting angle having a stress resistance smaller than that of the resonator crystal piece 2, such as an AT cut, the holding crystal plate 10 absorbs stress distortion and is not transmitted to the resonator crystal piece 2. Therefore, it is suitable (nonpatent literature 1).

  In this embodiment, in particular, the holding crystal plate 10 is fixed to the inner wall step which is the inner surface of the container body 1 at the center of both ends, and the vibrator crystal piece 2 is fixed to both ends of the holding crystal plate 10. The Therefore, even if stress distortion in the length direction (for example, bending in the length direction) occurs in the holding crystal plate 10 due to a difference in thermal expansion coefficient between the holding crystal plate 10 and the container main body 1 (ceramic), the holding crystal plate 10 is held. Since the center of both ends of the crystal plate 10 is held, both end sides in the width direction become free ends and no stress distortion occurs. The vibrator crystal piece 2 has both ends fixed to the holding crystal plate 10 and has the same thermal expansion coefficient, so that no stress distortion occurs in the vibrator crystal piece 2.

  In this case, the temperature in the tank of the container body 1 having a constant temperature structure is controlled within ± α ° with reference to the operating temperature (extreme temperature 80 ° C.). Therefore, even if the temperature in the tank changes from the extreme temperature T (80 ° C.) by an allowable range of ± α °, the frequency changes in opposite directions due to stress strain with respect to the temperature change around the extreme temperature. Suppress.

  From this, even if there is a change within the allowable range ± α ° from the operating temperature T (80 ° C.) in the tank temperature of the container body 1, only the frequency change due to the SC cut frequency temperature characteristic occurs, and the frequency due to stress strain Change can be ignored. Therefore, the frequency deviation standard f 0 ± β ppm becomes dominant and depends on the frequency temperature characteristic, so that the design of the constant temperature type vibrator is facilitated.

  In this embodiment, the holding crystal plate 10 is fixed to the inner wall step (inner surface) at the center of both ends, and the resonator crystal piece 2 is fixed to both ends of the holding crystal plate 10. If the fixing position of the holding crystal plate 10 to the inner surface and the fixing position of the vibrator crystal piece 2 to the holding crystal plate 10 are different, the stress distortion generated in the vibrator crystal piece 2 is alleviated.

  Further, although both the temperature sensitive resistor 3 and the heating resistor 4 are formed exposed on the surface as film resistance, for example, the heating resistor 4 may be formed on the laminated surface of the bottom wall or the inner bottom surface (recess bottom surface). “FIG. 2 (ab)”. In this case, since the heating resistor 4 is shielded from the outside air, the heating effect can be enhanced.

  Further, both the temperature sensitive resistor 3 and the heating resistor 4 may be formed on the outer bottom surface of the container body 1 (not shown). The temperature sensitive resistor 3 and the heat generating resistor 4 are the same even if any one or both are formed as a chip element. FIG. 2 (c) shows an example in which the temperature sensitive resistor 3 and the plurality of heating resistors 4 are formed on the bottom surface of the recess.

  Further, in this embodiment, the inner wall step portion is provided and the center of both end portions of the holding crystal plate 10 is fixed. However, as shown in FIG. 3, for example, the thickness of the conductive adhesive 9 is not provided without the inner wall step portion. For example, the gap may be fixed to the bottom surface of the recess with a gap. However, there is no particular problem even if it comes into contact with the facing surface of the holding crystal plate 10. Thereby, a height dimension can be made small. Of course, when a chip element is disposed on the bottom surface of the recess, an inner wall step is required.

  Further, although the vibrator crystal piece 2 is illustrated as a flat plate shape, it may be a bevel or a convex shape. In this case, a pillow (not shown) for preventing contact of the vibration region where the excitation electrode 8a is formed may be provided at the other end of the holding crystal plate 10, or a recess may be provided on the surface facing the vibrator crystal piece 2. You can also.

(Second Embodiment)
FIG. 4 is a diagram for explaining a second embodiment of the present invention, in which FIG. 4 (a) is a cross-sectional view of a thermostatic transducer, FIG. 4 (b) is a plan view of a container body, and FIG. FIG. In the following embodiments, the same parts as those in the previous embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

  In this embodiment, the holding crystal plate 10 has the crystal holding terminals 6 on both sides of one end portion of one main surface as described above, and both ends of the one end portion of the crystal piece 2 for vibrator with the lead electrode extended are conductive adhesive. 9 is fixed. In this case, the crystal holding terminal 6 is electrically connected to the conduction terminals 11 provided at both ends in the width direction so as to be closer to the center than both sides of one end of the other main surface through the outer surface.

  Correspondingly, the conductive terminal 11 is fixed to the circuit terminal 12 provided on the inner bottom surface of the container body 1 by the conductive adhesive 9. In short, the fixing position in the length direction with respect to the inner bottom surface of the holding crystal plate 10 is different from the fixing position in the same direction with respect to the holding crystal plate 10 of the vibrator crystal piece 2.

  Here, the center of the other end of the holding crystal plate 10 is fixed by a conductive or insulating adhesive 9a to increase the stability by holding three points. The conductive adhesive 9 and the adhesive 9a are both polyimide-based, which generates less organic gas. A temperature sensitive resistor 3 is formed on the inner bottom surface of the container body 1 and a heating resistor 4 is formed on the outer bottom surface in the same manner as described above.

  Then, the external terminal 7 of the vibrator crystal piece 2 provided on the outer bottom surface of the container body 1 is connected to the oscillation circuit, and the external terminals 7 of the temperature sensitive resistor 3 and the heating resistor 4 are connected to the temperature control circuit. As described above, the operating temperature of the crystal resonator is controlled within the extreme temperature T (80 ° C.) ± α °, and the frequency deviation standard of the oscillation frequency is set to f 0 ± β ppm.

  In such a case, the fixing position of the resonator crystal piece 2 to the holding crystal plate 10 is on both sides of one end, and the fixing position to the inner bottom surface of the holding crystal plate 10 is on both ends of one end closer to the center. The position of fixing in the length direction is varied. Therefore, even if a stress strain occurs in the width direction between the fixing positions near the center of the holding crystal plate 10 due to the difference in thermal expansion coefficient with the container body 1, the stress strain on both sides of the one end separated from the center is reduced. .

  As a result, both sides of the one end of the vibrator crystal piece 2 and the holding crystal plate 10 are expanded and contracted in the width direction based on the same thermal expansion coefficient, so that the vibrator crystal piece 2 is stress-strained in the same direction. Does not occur. Further, since the other end portion of the vibrator crystal piece 2 in the length direction is a free end, no stress distortion occurs in the same direction.

  Therefore, as in the first embodiment, even if the temperature in the tank changes from the extreme temperature T (80 ° C.) by an allowable range of ± α °, the stress changes due to the temperature change centered on the extreme temperature. To suppress frequency changes in opposite directions. As a result, the frequency deviation standard f 0 ± β ppm becomes dominant and depends on the frequency temperature characteristic, thereby facilitating the design of the constant temperature type vibrator.

  In the second embodiment, as in the first embodiment, the temperature sensitive resistor 3 and the heating resistor 4 can be provided at any location of the container body 1. And, for example, as shown in FIG. 5, an inner wall step is formed on the container body 1 to provide a circuit terminal 12, which is connected to the conduction terminal 11 by a conductive adhesive (not shown). The temperature sensitive resistor 3 and the heating resistor 4 can be provided.

(Third embodiment)
FIG. 6 is a diagram for explaining a third embodiment of the present invention, where FIG. 6 (a) is a cross-sectional view of a thermostatic transducer, FIG. 6 (b) is a plan view of a container body, and FIG. FIG.

  In the third embodiment, for example, the temperature sensitive resistor 3 and the heat generating resistor 4 which are both film resistors are formed on the holding crystal plate 10. As described above, the holding crystal plate 10 has crystal holding terminals 6 on both sides of one end portion of one main surface, and is electrically connected to the conduction terminal 11a closer to the center of the other main surface. Both ends of the extended end portion of the lead electrode of the crystal piece 2 for vibrator are fixed to the crystal holding terminal 6.

  Here, the temperature sensitive resistor 3 is formed on one main surface of the holding crystal plate 10 facing the crystal plate 2 for vibrator, and the heat generating resistor 4 is formed on the other main surface. These are all the central region of the holding crystal plate 10. A wiring path (not shown) extends from the temperature sensitive resistor 3 and the heating resistor 4 and is electrically connected to a conduction terminal 11 (bc) provided on the other end side of the other main surface of the holding crystal plate 10.

  The conduction crystal terminal 2 (abc) of the resonator crystal piece 2, the temperature sensitive resistor 3 and the heating resistor 4 are not shown in the circuit terminal 12 (abc) on the inner bottom surface of the container body 1 provided corresponding thereto. It is fixed by a conductive adhesive. These circuit terminals 12 (abc) are electrically connected to the external terminals 7 on the outer bottom surface.

  Even in such a configuration, the fixing position of the vibrator crystal piece 2 to the holding crystal plate 10 and the fixing position to the inner bottom surface of the holding crystal plate 10 are different in the length direction. Therefore, similarly to the second embodiment, the stress distortion due to the difference in thermal expansion coefficient between the both end sides in the width direction near the center which is the fixing position with the container body 1 is separated from the holding crystal plate. 10 is reduced on both sides of one end.

  As a result, the vibrator crystal piece 2 to which both ends of the one end are fixed expands and contracts together with the holding crystal plate 10, so that stress distortion is suppressed. Therefore, even if the temperature in the tank changes, frequency changes in opposite directions due to stress strain are suppressed, so that it is easy to design a thermostat type vibrator that maintains high frequency accuracy.

  In the third embodiment, the temperature sensitive resistor 3 and the heat generating resistor 4 are formed as film resistors on both main surfaces of the holding crystal plate 10. However, for example, a step or a recess is formed on the holding crystal plate 10. It can also be a chip element. Then, either the temperature sensitive resistor 3 or the heat generating resistor 4 can be formed on the holding crystal plate 10 and the other can be formed at an arbitrary location on the container body.

(Fourth embodiment)
FIG. 7 is a view for explaining a fourth embodiment of the present invention. FIG. 7 (a) is a cross-sectional view of a constant temperature type vibrator, FIG. 7 (b) is a plan view of a crystal piece, and FIG. FIG. 4D is a plan view of the container body.

  In the embodiment of FIG. 4, the quartz crystal piece 2 for vibrator extends from the excitation electrodes 8a on both main surfaces to the extraction electrodes 8b at both ends. The holding crystal plate 10 has a crystal holding terminal 6 at the center of both ends, and the center of both ends of the crystal plate 2 for vibrator is fixed by a conductive adhesive 9. The crystal holding terminals 6 are electrically connected to the conduction terminals 11 provided on both end sides in the length direction of the other main surface.

  Correspondingly, the conductive terminal 11 is fixed to the circuit terminal 12 provided on the inner bottom surface of the container body 1 by the conductive adhesive 9. In short, the fixing position in the width direction of the vibrator crystal piece 2 with respect to the holding crystal plate 10 is different from the fixing position in the same direction with respect to the inner bottom surface of the holding crystal plate 10.

  Here, the center of the long side opposite to the long side on which the conductive terminal 11 is formed is fixed by the conductive or insulating adhesive 9a to maintain the three points, thereby increasing the stability. Also in this example, both the conductive adhesive 9 and the adhesive 9a are polyimide. A temperature sensitive resistor 3 is formed on the inner bottom surface of the container body 1 and a heating resistor 4 is formed on the outer bottom surface in the same manner as described above.

  In such a case, the fixing position of the vibrator crystal piece 2 to the holding crystal plate 10 and the fixing position to the inner bottom surface of the holding crystal plate 10 are made different in the width direction. Therefore, even if stress strain in the length direction is generated between the fixing positions on the long side of the holding crystal plate 10 due to the difference in thermal expansion coefficient with the container body 1, the vibrator crystal piece 2 of the vibrator crystal piece 2 is separated from this. Stress strain between the centers of both ends to be fixed is reduced.

  As a result, the center of both ends where the resonator crystal piece 2 and the holding crystal plate 10 are connected are expanded and contracted in the length direction based on the same thermal expansion coefficient, so that the resonator crystal piece 2 is stressed in the same direction. Does not generate distortion. Further, since both end portions in the width direction of the crystal unit 2 for vibrator are free ends, no stress distortion occurs in the same direction.

  Therefore, as in each embodiment, even if the temperature in the tank changes, frequency changes in opposite directions due to stress strain are suppressed, so it is easy to design a thermostatic oscillator that maintains high frequency accuracy. To. In addition, although the center of both ends of the resonator crystal piece 2 is fixed, the effect is enhanced when it is separated from the fixing position with respect to the inner bottom surface of the holding crystal plate 10, so that it is opposite to the long side where the conduction terminal 11 is formed. You may hold | maintain the both ends of the other long side used as the side.

  In this embodiment, as in the third embodiment, the temperature sensitive resistor 3 and the heat generating resistor 4 can be formed on the holding crystal plate 10, and the temperature sensitive resistor 3 and the heat generating resistor 4 can be arbitrarily formed. It can be arranged as a position or chip element.

(Other matters)
In the above embodiment, the constant temperature crystal device for surface mounting has been described as a constant temperature oscillator. For example, as shown in FIGS. 8 (abc), 9 and 10 (ab), the IC chip 13a A constant temperature crystal oscillator can be configured by integrally housing circuit elements 13 such as temperature compensation elements and oscillation circuit elements. FIG. 8 (abc) is a cross-sectional view, and the external terminals are a power source, an output, a ground, and the like.

  FIG. 8 (abc) is an example using the container body 1 having a recess only on one main surface. For example, in FIG. 8A, the temperature sensitive resistor 3, the heating resistor 4 and the circuit element 13 are arranged on the bottom surface of the recess, and the holding crystal plate 10 is joined to the inner wall step. In FIG. 8B, the holding crystal plate 10 is arranged on the bottom surface of the recess, and the circuit board 14 having the temperature sensitive resistor 3, the heating resistor 4 and the circuit element 13 is provided on the inner wall step. In FIG. 8 (c), the inner wall stepped portion has two steps, and the vibrator crystal piece 2 is hermetically sealed by the first-stage inner lid 15, and is separated from the substrate 14 on the second step surface.

  In FIG. 9, the crystal piece 2 for the vibrator, the temperature sensitive resistor 3 and the heating resistor 4 are provided on the lower surface of the holding crystal plate 10, and the circuit element 13 is provided on the upper surface of the holding crystal piece 10. Then, both end portions of the lower surface of the holding crystal plate 10 where the terminals such as the oscillation circuit are formed are fixed to the inner wall step portion. Even in this case, the fixing position of the holding crystal plate 10 to the inner wall step portion and the fixing position of the vibrator crystal piece 2 to the holding crystal plate 10 are different. Therefore, even if stress distortion occurs between the holding crystal plate 10 and the inner wall step, the stress distortion of the vibrator crystal piece 2 is alleviated.

  The holding crystal plate 10 in FIGS. 8 (bc) and 9 is fixed to the inner wall step portion to shield the metal cover 5 and the vibrator crystal piece 2. FIG. Therefore, a heat insulating space layer is formed between the holding crystal plate 10 and the metal cover 5. As a result, the quartz crystal piece 2 for vibrator is less susceptible to changes in the outside air temperature (ambient temperature), and frequency fluctuations due to thermal shock due to sudden temperature changes can be prevented.

  FIG. 10 (ab) shows an example in which a container body 1 having recesses on both main surfaces is used. For example, in FIG. 10 (a), the holding crystal plate 10 provided with the temperature sensitive resistor 3 and the heating resistor 4 is provided in the concave portion on one main surface, and the circuit element 13 including the IC chip 13 is provided on the other main surface. FIG. 10 (b) shows an example in which the circuit board 14 on which the circuit elements 13 are arranged is joined to the recesses on the other main surface. It should be noted that the present invention is not limited to these arrangement configurations and can be arbitrarily configured as necessary.

  Furthermore, although the crystal resonator is SC cut, it may be, for example, an AT cut that has the highest frequency of use and has a minimum frequency temperature characteristic in the vicinity of 80 ° C. A crystal resonator (crystal piece) having a frequency temperature characteristic having a value can be applied. The conductive adhesive is a polyimide based material that suppresses the generation of organic gas, but may be fixed using, for example, a eutectic alloy such as AuSn.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining 1st Embodiment of this invention, The figure (a) is sectional drawing of a thermostat type vibrator, The figure (b) is a top view of a container main body, The figure (c) is a plane of a holding substrate. FIG. It is a figure explaining other examples of a 1st embodiment of the present invention, and the figure (abc) is a sectional view of a constant temperature type vibrator. FIG. 6 is a cross-sectional view of a constant temperature oscillator for explaining still another example of the first embodiment of the present invention. FIG. 6 is a diagram for explaining a second embodiment of the present invention, in which FIG. (A) is a cross-sectional view of a thermostatic transducer, FIG. (B) is a plan view of a container body, and (c) is a plan view of a holding substrate. FIG. It is sectional drawing of the thermostat type | mold explaining the other example of 2nd Embodiment of this invention. FIG. 6 is a diagram for explaining a third embodiment of the present invention, in which FIG. (A) is a cross-sectional view of a thermostatic transducer, FIG. (B) is a plan view of a container body, and (c) is a plan view of a holding substrate. FIG. FIG. 6A is a cross-sectional view of a thermostatic oscillator, FIG. 5B is a plan view of a crystal piece, and FIG. 4C is a plan view of a holding substrate. The figure and the figure (d) are top views of a container main part. It is a figure explaining other embodiment of this invention, and the same figure (abc) is sectional drawing of the crystal oscillator made into the constant temperature type. It is sectional drawing of the crystal oscillator made into the constant temperature type explaining further another embodiment of this invention. FIG. 6 is a diagram for explaining still another embodiment of the present invention, and FIG. 5B is a cross-sectional view of a constant temperature crystal oscillator. It is a figure explaining a prior art example, the figure (a) is a sectional view of a thermostat type vibrator, and the figure (b) is a top view of a crystal piece. It is a frequency temperature characteristic of the crystal resonator made into SC cut explaining a prior art example.

Explanation of symbols

1 Container body, 2 Crystal piece, 3 Temperature sensitive resistor, 4 Heating resistor, 5 Metal cover,
6 Crystal holding terminal, 7 External terminal, 8a Excitation electrode, 8b Lead electrode, 9 Conductive adhesive, 10 Holding crystal plate, 11 Conducting terminal, 12 Circuit terminal, 13 Circuit element

Claims (8)

  A container main body having a recess made of a bottom wall and a frame wall on at least one main surface, and housing the crystal quartz piece for vibrator in the recess, and a heating resistor housed in the container main body for heating the crystal quartz piece for vibrator And a temperature-sensitive resistor for detecting an operating temperature of the vibrator crystal piece, and a cover provided on an opening end surface of one main surface of the container body, and maintaining the operating temperature of the vibrator crystal piece constant. In the constant temperature crystal device for surface mounting, the crystal piece for the vibrator faces the holding crystal plate fixed in a horizontal direction on the inner bottom surface of the container body, and is drawn from the excitation electrode of the crystal piece for the vibrator. The outer peripheral part where the electrode extends is fixed to the holding crystal plate, the fixing position of the holding crystal plate to the inner surface of the container body, and the fixing position of the vibrator crystal piece to the holding crystal plate Is different Constant-temperature type quartz crystal device according to claim Rukoto.   2. The constant temperature crystal device according to claim 1, wherein an operating temperature of the vibrator crystal piece is an extreme temperature at which the operating temperature of the frequency temperature characteristic is equal to or higher than room temperature, or an extreme temperature at which the operating temperature becomes a minimum value.   3. The constant temperature crystal device according to claim 2, wherein the quartz crystal piece for vibrator is an SC cut having a maximum value above the room temperature of the frequency temperature characteristic or an AT cut having a minimum value above the room temperature of the frequency temperature characteristic.   2. The constant temperature crystal device according to claim 1, wherein the vibrator crystal piece is fixed to the holding crystal plate with a polyimide conductive adhesive.   2. The holding crystal plate according to claim 1, wherein the extraction electrode extends to both sides of one end portion of the vibrator crystal piece, and both ends of the one end portion of the vibrator crystal piece are fixed to both sides of one end portion of the holding crystal plate. Is a constant temperature crystal device in which the center of both end portions in the length direction is fixed to the inner surface of the container body.   2. The holding crystal plate according to claim 1, wherein the extraction electrode extends to both sides of one end portion of the vibrator crystal piece, and both ends of the one end portion of the vibrator crystal piece are fixed to both sides of one end portion of the holding crystal plate. Is a constant temperature crystal device in which both ends in the width direction closer to the center than both sides of the one end are fixed to the inner surface of the container body.   2. The extraction electrode according to claim 1, wherein the lead electrodes extend to both end portions of the vibrator crystal piece, and both end portions of the vibrator crystal piece are fixed to both end portions of the holding crystal plate. Are fixed to the inner surface of the container main body, and the fixing positions of the both ends of the crystal piece for vibrator to the holding crystal plate and the fixing positions of the both ends of the holding crystal plate to the inner surface are in the width direction. Different constant temperature crystal devices.   The constant temperature crystal device according to claim 1, wherein the container body is provided with at least a temperature control circuit element or an oscillation circuit element.