JP4019473B2 - Electronic devices - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a piezoelectric device, and in particular, facilitates an operation for adjusting variations in temperature-frequency characteristics of piezoelectric elements housed in a package, and increases the degree of freedom in arrangement when an oscillator is configured in a radio device or the like. The present invention relates to a chip component composite piezoelectric device suitable for the above.
[0002]
[Prior art]
In a conventional piezoelectric device, for example, a crystal resonator or a SAW resonator, in order to prevent deterioration of the element due to outside air, the piezoelectric element is generally stored in a sealed container in a sealed state. By the way, as an electronic circuit component using these piezoelectric devices, a Colpitts type oscillation circuit using an AT-cut crystal resonator is well known, and when the stability of the oscillation frequency with respect to temperature is required, a temperature compensation circuit is further provided. TCXO (temperature compensated crystal oscillator) marked with is used. As a method of temperature compensation by the temperature compensation circuit, a variable reactance element such as a varicap is connected in series to the piezoelectric element, and a method called an indirect type in which the terminal voltage is controlled according to the temperature, piezoelectric vibration A method called a direct type in which a compensation circuit composed of a parallel circuit of a temperature sensitive resistance element such as a thermistor and a capacitor is connected in series to a child, and a method of digitally processing the indirect type is also known. . Such TCXO is mainly used in wireless communication devices such as portable wireless devices. These piezoelectric devices such as TCXO have been miniaturized and reduced in profile year by year in order to meet the demand for miniaturization, and now packages with a capacity of 0.2 cc or less appear. Has reached. On the other hand, as a distribution channel of TCXO, a package of TCXO packaged by a piezoelectric element manufacturer such as quartz or an electronic component manufacturer is supplied to a device manufacturer, and the device manufacturer generally incorporates it into a wireless device or the like.
[0003]
[Problems to be solved by the invention]
However, conventional oscillators such as TCXO have the following requirements and problems. That is, although the miniaturization has progressed, the TCXO is relatively large compared to other electronic components, and occupies a considerable area when mounted on the printed board of the radio body. Therefore, the degree of freedom of arrangement of peripheral parts is limited. That is, if a device manufacturer such as a radio device can freely determine the arrangement of the TCXO element parts according to the balance with other peripheral components, the size of the entire radio device may be reduced. In addition, parts completed as TCXO, etc., have certain requirements such as the relationship between the operating temperature range of the radio and the frequency stability, power supply voltage, and even modulation when using TCXO as part of the modulator. Generally, it is made based on the specifications such as sensitivity. For this reason, the TCXO made for a specific radio on the piezoelectric device manufacturer side may not be applicable to other models with different specifications, and may lack general versatility. On the other hand, when considering a single piezoelectric vibrator incorporated in the TCXO, the temperature frequency characteristic of the piezoelectric vibrator is actually varied due to variations in the cut angle of each crystal or the like. In TCXO, variations are individually adjusted by exchanging peripheral components of the vibrators of these piezoelectric devices. If a TCXO is configured by directly mounting a crystal unit on a printed circuit board such as a radio device, a temperature test is performed on a block completed as a TCXO at a required part of the printed circuit board such as a radio device, and the frequency stability is If it is not satisfied, the capacitor value and the resistance value are exchanged, and further, the temperature test is repeated. It is considered that this cause is mainly due to variations in characteristics of piezoelectric devices such as quartz resonators as described above. That is, if the various characteristics of the individual piezoelectric devices are uniform, the complicated work load as described above can be reduced.
[0004]
Therefore, in order to make the individual characteristics of the piezoelectric device uniform, there has been proposed one in which a characteristic compensation component such as a capacitor or a resistor is housed in a sealed container together with the piezoelectric device. That is, if frequency deviations and characteristics caused by manufacturing errors such as cut angles are changed and the values of capacitors, resistors, or coils are changed, the characteristics of each piezoelectric device are made uniform and supplied to radio equipment manufacturers, etc. The above problems when a TCXO circuit or the like is directly incorporated into a printed circuit board of a radio can be solved. However, when adjusting the characteristics of a piezoelectric device that has been sealed in the past by adjusting the values of elements having a temperature compensation function, i.e., capacitors, resistors, etc., provided in the package, the lid of the package is used. However, the characteristics of the piezoelectric device may differ from the state in which the piezoelectric vibrator is sealed. After sealing, the temperature frequency characteristics changed and it was difficult to adjust the characteristics stably. The present invention has been made in view of such circumstances, and an object of the present invention is to provide a piezoelectric device suitable for a radio maker to configure an oscillator and a filter in accordance with their own wishes.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a central portion on the outer bottom surface of a substantially rectangular package body having electrode terminals for surface mounting on the outer bottom surface and accommodating at least a second electronic component therein. Having four cross-shaped protrusions extending toward the center of the four sides, and electrode terminals for surface mounting are disposed on the bottom surfaces of the end portions of the protrusions, at the four corners of the outer bottom surface of the package body. The first electronic component is accommodated in at least one of the recessed portions positioned.
Further, the present invention is characterized in that the first electronic component has a function of temperature-compensating at least electrical characteristics of the second electronic component.
Further, the present invention is characterized in that the first electronic component is any one of a capacitive element, a variable capacitive element, a reactance element, or a semiconductor.
In addition, the present invention is characterized in that the second electronic component uses a piezoelectric material.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to embodiments shown in the accompanying drawings. FIG. 1 is a circuit diagram showing one embodiment of the composite piezoelectric vibrator of the present invention. That is, in this circuit, a parallel circuit of two capacitors C1 and C2 is connected in series with the AT-cut crystal resonator X. The composite piezoelectric vibrator shown in FIG. 1 can be used as a part of a conventionally known Colpitts oscillation circuit or a part of a clock OSC using an inverter. FIG. 2 is a structural view showing an embodiment according to the present invention in which the circuit component is housed, wherein (a) is a top view, (b) is a side view, (c) is a front view, and (d) is a front view. A bottom view and (e) are AA sectional views. The characteristic configuration of this embodiment is shown in FIGS. That is, as shown in (d), the outer bottom surface of the package body 1 is provided with, for example, a recessed portion 2 extending from the center portion to the front surface, and a predetermined interval is provided on the ceiling surface of the recessed portion 2. Two opposing electrodes 3 and 4 are formed so as to be opposed to each other, and are connected to package electrode terminals H2 and TC exposed on the outer bottom surface by a conductive pattern penetrating the package body. Two chip capacitors C1 and C2 (first electronic components) are mounted between the four. Further, as shown in FIG. 4E, inside the package body, an AT-cut quartz crystal unit X (second electronic component) is electrically conductive in a cantilevered state on one electrode pad 6 on the internal support 5. It is supported and fixed via an adhesive 7. The recessed portion 2 has an opening 2a on the front side thereof, and even when the bottom surface side of the package body 1 is mounted on a printed board, the inside of the recessed portion 2 communicates with the outside air, A gas vent is used to eliminate problems caused by heat and gas trapped in the recess. In addition, the formation position of the opening 2a may be not only the front side shown in the figure, but also the rear side, or one of the right side and the left side, and further, the front side, the rear side, the left and right Openings may be provided at two, three, or four of the lateral sides so that the inside of the recessed portion communicates with the outside.
[0007]
Next, the circuit configuration shown in FIG. 1 is realized by the configuration shown in FIG. 2. According to this configuration, the concave portions provided on the outer bottom surface of the package by the capacitors C1 and C2 added for characteristic compensation are provided. 2 and is connected to the vibrator inside the package and the external terminals H2 and TC, so that the capacitors C1 and C2 can be exchanged as necessary when the vibrator is sealed. Fine adjustment of high-precision characteristics becomes easy. In an actual circuit, the effect of characteristic compensation is greater when at least one of the capacitors C1 and C2 is a temperature compensation capacitor whose capacitance value changes according to temperature. The reason and effect will be described below. Here, TCXO (temperature compensated oscillator) will be mainly described as an example using the piezoelectric device of the present invention. That is, consider a case where a TCXO (temperature compensated oscillator) as shown in FIG. 3 is configured using a composite piezoelectric vibrator of the crystal resonator X and capacitors C1 and C2 as shown in FIG. The circuit shown in FIG. 3 is a well-known Colpitts oscillator. The amplifier includes the piezoelectric device (AT-cut crystal resonator) of the present invention, the above-described direct type or indirect type compensation circuit, and fine frequency adjustment. For example, an AT-cut quartz resonator has a variation in a certain range of temperature / frequency characteristics due to a manufacturing error of a cut angle as described above. Therefore, in the present invention, as shown in the circuit diagram of FIG. 1, a parallel circuit of capacitors C1 and C2 is connected in series to the crystal resonator X, and both or one of the capacitors C1 and C2 is temperature-controlled. As a result, even if there is variation in the cut angle of the crystal resonator, the resonance frequency of the entire circuit including the capacitor satisfies the standard value at the normal temperature value, and the temperature characteristics are also Adjustment is possible so as to obtain a desired value. That is, if the temperature characteristic of the capacitor is appropriately selected according to the variation in the cut angle of the crystal resonator, the temperature characteristic of the overall frequency can be made uniform for each device. At this time, in the present invention, since the capacitor is disposed in the recessed portion provided on the outer surface of the package, the characteristic adjustment can be performed from the outside of the package in a sealed state. As a result, there is no need for the wireless device manufacturer that purchased the piezoelectric device from the piezoelectric vibrator manufacturer to adjust the characteristics by itself. If this is necessary, the radio equipment manufacturer can replace the capacitor. As a temperature compensating capacitor, for example, a negative temperature characteristic, that is, a U characteristic in which a capacitance value decreases as the temperature rises is well known. If the cut angle of the crystal unit X is as specified, the C1 and C2 capacitors do not need to be temperature-compensated, and if that is the case, select a capacitor with flat temperature characteristics, for example, one with C characteristics. Good.
[0008]
FIG. 4 shows a capacitor having a negative temperature characteristic, for example, a relationship between the capacitance of the U characteristic and the temperature. This is a capacitor whose capacitance value decreases as the temperature rises. If this capacitor is used for C1 and C2, for example, the temperature characteristics of the AT-cut quartz crystal resonator indicated by broken lines in FIG. 5 can be compensated so that the frequency decreases on the low temperature side and increases on the high temperature side. If the capacitor has a positive temperature characteristic, it can be compensated to increase the frequency on the low temperature side and decrease it on the high temperature side. Further, if only one of the capacitors C1 and C2 is a temperature compensation type capacitor, the compensation amount can be arbitrarily set according to the ratio of the capacitance values of both capacitors. As described above, if the composite piezoelectric vibrator having the circuit configuration shown in FIG. 1 is manufactured and the temperature characteristics of the capacitor are appropriately selected to correct the variation in the cut angle of the crystal vibrator, the piezoelectric device can be obtained. Since the overall frequency-temperature characteristics of each individual can be made almost uniform, when using these to configure TCXO or other oscillators, and filters, etc., the effects of cut angle variations are a concern. Thus, the peripheral circuit element value can be determined without the need for troublesome work of replacing the TCXO circuit element after mounting.
[0009]
FIG. 6 is an equivalent circuit diagram showing a modification of the present invention. This embodiment is characterized in that a trimming resistor R is connected in parallel to the parallel capacitors C1 and C2 in the circuit of FIG. As is well known, the trimming resistor is a resistor component having a function of changing a resistance value by forming a resistor on a substrate by a thick film technique or the like and partially cutting it by laser or the like or mechanical cutting. Specifically, a plate-like component in which the above-described resistor is formed on the outer peripheral surface of the package body 1 shown in FIG. 2 or a part of the recessed portion 2 for mounting the capacitors C1 and C2 or a trimming resistor is formed. May be additionally connected so as to have the circuit configuration shown in FIG. According to this configuration, as is well known, a parallel circuit of a capacitor and a resistor functions as an electrically equivalent series circuit, and the equivalent series capacitance is a function of the resistor R. Therefore, if the resistance value is changed by trimming, the capacitance value acting in series with the crystal resonator can be arbitrarily changed. According to this configuration, if the frequency temperature characteristic of the assembled piezoelectric vibrator or the resonance frequency at the reference temperature is different from the desired value, the desired value can be obtained by adjusting the resistance value by trimming.
[0010]
Next, FIGS. 7A and 7B are perspective views showing the package structure of another embodiment of the present invention, respectively, and FIG. 7A shows at least one chip-type electron directly on one side of the package body 1. A characteristic is that the component is mounted, and the electronic component, the piezoelectric vibrator in the package body, and the electrode terminals of the package are connected by a conductive pattern. In the embodiment shown in FIG. 7 (a), electrodes 3 and 4 for mounting the chip-type electronic component 10 are arranged opposite to each other at a predetermined interval on an appropriate side surface of the package body 1, for example, at the center as shown in the figure. The electronic component 10 is soldered with the electrodes 3 and 4 being straddled. The configuration in which the electronic component 10, the piezoelectric vibrator in the package body, and the electrode terminals of the package are connected by a conductive pattern is the same as in the above embodiment. Next, in the embodiment shown in FIG. 7B, when the chip-type electronic component 10 is mounted on the center of one side surface of the package body 1 as in the embodiment shown in FIG. In addition, the electrodes 3 and 4 are disposed on the inner bottom surface of the recessed portion 11, and the chip-type electronic component 10 is soldered on both electrodes. The configuration in which the electronic component 10, the piezoelectric vibrator in the package body, and the electrode terminals of the package are connected by a conductive pattern is the same as in the above embodiment. In this embodiment, since the mounting location of the chip component is located on the outer surface, mounting is easy, and heat and gas are not trapped around the chip component. Also, a low profile can be realized.
[0011]
Next, FIG. 8 is a top perspective view showing a package structure according to another embodiment of the present invention, and a concave portion 15 is provided at an appropriate position on the upper surface (cap) of the package main body 1, in this example, on the two opposite edge sides. The electrodes 3 and 4 are arranged at predetermined intervals on the inner bottom surface of each recess 15, and the chip-type electronic component 10 is solder-connected across both electrodes. The configuration in which the electronic component 10, the piezoelectric vibrator in the package body, and the electrode terminals of the package are connected by a conductive pattern is the same as in the above embodiment. In this embodiment, since the mounting location of the chip component is located on the upper outer surface, it is easy to mount the chip component, the mounted component does not fall, and heat and gas are not trapped around the chip component. Also, it is possible to reduce the height of parts.
[0012]
Next, FIGS. 9A to 9D are a plan view, a side view, a front view, and a bottom view showing the package structure of another embodiment of the present invention. In this embodiment, a cross-shaped protrusion 20 (the bottom surface is a flat surface) is provided on the bottom surface of the package body 1, and electrode pads H1, H2, TC, and GND are provided on the bottom surfaces of the four end portions of the protrusion 20, The structure is characterized in that electrodes 3 and 4 for solder-connecting the chip-type electronic component 22 are formed on the ceiling surface of each recess 21 located at the four corners of the bottom surface. The configuration in which the chip-type electronic component 22, the piezoelectric vibrator in the package body, and each electrode terminal of the package are connected by a conductive pattern is the same as that in the above-described embodiment.
[0013]
FIG. 10 is an equivalent circuit diagram of the package structure of the embodiment of FIG. 9. Since the package body of this embodiment has four recesses 21 for accommodating chip-type electronic components, for example, each recess 21 has a respective one. One chip part can be arranged. In this case, as shown in FIG. 10, the thermistor TH1, the fixed resistor R1, and the fixed capacitors C1 and C2 are connected as shown. In this case, temperature compensation of the piezoelectric vibrator is performed by a parallel circuit of the thermistor TH1 and the capacitor C1. In the above description of each embodiment, the crystal resonator is exemplified as the piezoelectric element. However, the present invention is not limited to this, and any piezoelectric element or other element may be used. For example, the present invention can be widely applied to an element that requires compensation of temperature characteristics, such as a delay element using a SAW resonator or a piezoelectric material. Further, the components connected to these piezoelectric elements are not limited to capacitors, and may be coils, variable capacitance elements, variable reactance elements constituted by semiconductors, or the like.
[0014]
【The invention's effect】
As described above, according to the present invention, since the individual characteristics of the piezoelectric device itself are made uniform, a radio device manufacturer can provide a piezoelectric device suitable for configuring an oscillator or the like according to his / her wishes. In this case, it is possible to provide a chip component composite piezoelectric vibrator that facilitates complicated temperature-frequency characteristic adjustment work and is suitable for miniaturization. That is, the characteristic adjustment of the piezoelectric device can be easily performed from the outside of the package of the piezoelectric device in a sealed state. As a result, adjustment work after the piezoelectric device is incorporated into the wireless device, replacement of the piezoelectric device once mounted on the substrate, and the like can be eliminated.
That is, according to the present invention, a concave portion having an unsealed structure is provided on the outer bottom surface of a package containing at least a piezoelectric vibrator, and at least one chip-type electronic component is mounted in the concave portion, and the electronic component and the piezoelectric component are mounted. Since the required parts of the vibrator and the electrode terminal of the package are connected by a conductive pattern, the electronic component for adjusting the characteristics, which has been incorporated in the package in the past, is located in the recessed portion on the outer surface of the package. As a result, the characteristics can be easily adjusted from the outside of the package. If a piezoelectric device having uniform characteristics as described above is assembled in a wireless device or the like, it is not necessary to remove the device from the substrate and replace it after mounting. Further, since the recessed portion has a non-sealing structure, the recessed portion can be communicated with the outside air even when mounted on a printed circuit board, and gas and heat can be prevented from being trapped. That is, since the opening is eliminated by eliminating the minimum one side around the recess, heat and gas accumulation can be eliminated when mounting the vibrator on the printed circuit board.
[0015]
In the present invention, since the chip-type electronic component is disposed on the side surface or the edge of the upper surface of the package body, heat and gas accumulation are prevented, and a cavity portion is provided at the bottom. In comparison, there is no possibility that the mounted chip component will fall. Furthermore, the height can be reduced.
In the present invention, since the cross-shaped protrusion is provided on the bottom surface of the package body and the recesses for disposing the chip components are provided at the four corners of the bottom surface, the number of chip components to be mounted can be increased. The mounting workability when parts are required can be improved, and heat and gas accumulation during mounting can be prevented.
In the present invention, since the chip-type electronic component has a characteristic that the capacitance value changes according to the ambient temperature, it becomes easy to correct the variation in the cut angle of the piezoelectric vibrator in the piezoelectric device. That is, it is convenient to correct the variation in the cut angle of the piezoelectric vibrator by appropriately selecting the temperature characteristics of the capacitor.
[Brief description of the drawings]
FIG. 1 is a circuit diagram of a composite piezoelectric vibrator according to an embodiment of the present invention.
2 is a structural diagram showing an embodiment of the present invention for realizing the circuit of FIG. 1, wherein (a) is a top view, (b) is a side view, (c) is a front view, and (d) is a front view. A bottom view and (e) are AA sectional views.
FIG. 3 is a circuit diagram showing an example of a TCXO using the piezoelectric device of the present invention.
FIG. 4 is a graph showing one characteristic of a temperature compensation capacitor that can be used in the present invention.
FIGS. 5A and 5B are diagrams illustrating operational effects in one embodiment of the present invention. FIGS.
FIG. 6 is an equivalent circuit diagram showing a modification of the present invention.
FIGS. 7A and 7B are views showing a package structure according to another embodiment of the present invention. FIG.
FIG. 8 is a view showing a package structure according to another embodiment of the present invention.
FIGS. 9A to 9D are a plan view, a side view, a front view, and a bottom view showing a package structure according to another embodiment of the present invention.
10 is an equivalent circuit diagram of the package structure of FIG. 9;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Package body, 2 recessed part, 3, 4 counter electrode, 5 internal support stand, 6 electrode pad, 10 chip-type electronic component, 11 recessed part, 15 recessed part, 20 protrusion, 21 recessed part, 22 chip-type electronic parts.

Claims (4)

  A cross having an electrode terminal for surface mounting on the outer bottom surface and extending from the central portion toward the vicinity of the center of the four sides on the outer bottom surface of the substantially rectangular package body containing at least the second electronic component therein A protrusion of the mold, and electrode terminals for surface mounting are arranged on the bottom of each end of the protrusion, and at least one of the recesses located at the four corners of the outer bottom of the package body An electronic device comprising a single electronic component.   The electronic device according to claim 1, wherein the first electronic component has a function of temperature-compensating at least electrical characteristics of the second electronic component.   The electronic device according to claim 1, wherein the first electronic component is any one of a capacitive element, a variable capacitive element, a reactance element, or a semiconductor.   The electronic device according to claim 1, wherein the second electronic component uses a piezoelectric material.

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