JP4571830B2 - Piezoelectric vibrator - Google Patents

Description

  The present invention relates to a piezoelectric vibrator having an electrode structure for detecting a structural defect or defect of a portion that supports a vibration part.

  Conventionally, a contour vibration type piezoelectric vibrator represented by a lame mode or a width-length / length-length coupling mode has a structure in which the vibration part on which the excitation electrode is formed is fixed in a state of being floated from the casing. The casing is connected to the casing via an arm-shaped support portion having a springy elasticity extending from the end portion. As shown in Patent Document 1, the piezoelectric vibrator includes a vibrating portion in which excitation electrodes are formed on both front and back surfaces of a rectangular quartz substrate sliced from a quartz crystal at a predetermined cut angle, and an end portion of the vibrating portion. It is integrally formed by punching except for the supporting portion to be supported. An electrode pattern is formed on the support part, and one end thereof is a terminal electrode part. By applying a voltage supplied from the outside to the terminal electrode part, an electric field having an opposite phase is applied to the front and back surfaces of the vibration part. To generate a lame mode vibration in the vibration part.

  The structure of the conventional lame mode piezoelectric vibrator is shown in FIG. 9A shows the front surface of the piezoelectric vibrator 1, and FIG. 9B shows the back surface. In this piezoelectric vibrator 1, three excitation electrodes (5a, 6b, 7a) are formed on the surface of the rectangular vibration portion 2, and three excitation electrodes (5b, 6a, 7b) are formed on the back surface (3). 1) The following lame mode crystal resonator, in which the vibrating portion 2 is supported and integrated with the frame portion 4 via the supporting portions 3a to 3d. The frame portion 4 is formed with a pair of terminal electrodes 4a and 4b. From one terminal electrode 4a to the excitation electrode (5a-6a-7a) through the support portions 3c and 3d, from the other terminal electrode 4b. Voltages having opposite phases are applied to the excitation electrodes (5b-6b-7b) via the support portions 3a and 3b. As described above, the electric fields of the front and back surfaces of each excitation electrode and adjacent excitation electrode surfaces on the same plane are in opposite phases, so that higher-order Lamé mode vibration is generated in the vibration unit 2.

Further, the contour vibration type piezoelectric vibrator according to the width-longitudinal-longitudinal coupling mode is applied to a thin quartz substrate cut by a predetermined cut angle for obtaining vibration in the width-longitudinal-length longitudinal coupling mode. As shown in FIG. 10, the rectangular vibration part 12 and a pair of support parts 13 and 16 extending outward from the outer peripheral surface of the vibration part 12 are punched out. The vibrating part 12 has excitation electrodes 15a and 15b formed on the front and back surfaces, respectively. The one support portion 13 includes a lead portion 13c connected to the vibrating portion 12, a lead portion 13d connected to the terminal electrode 14a, and a pair of arms swelled outwardly between the lead portions 13c and 13d. The parts 13a and 13b are integrally formed. The other support portion 16 includes a lead portion 16c connected to the vibrating portion 12, a lead portion 16d connected to the terminal electrode 14b, and a pair of arm portions 16a bulging outwardly between the lead portions 16c and 16d. , 16b. Since the support portions 13 and 16 support the vibration portion 12 while absorbing the vibration, the support portions 13 and 16 are thin and long. In addition, since the vibrating portion 12 is supported in a well-balanced manner and is housed in a small casing and is also a route for supplying voltage, the pair of arm portions 13a and 13b and the arm portions 16a and 16b are substantially omitted. It is formed symmetrically. The electrode pattern is formed on the entire front surface or back surface of the support portions 13 and 16.
JP 57-197906 A JP 2001-31537 A

  By the way, in the contour vibration type piezoelectric vibrator 1 by the Lame mode, the electrode patterns from the terminal electrodes 4a and 4b to which a voltage is applied have support portions 3a and 3b and support portions 3c and 3d extending from two directions. Therefore, there are two systems of conductive routes in parallel for each excitation electrode formed in the vibration part 2. In such a configuration in which one excitation electrode is excited through two conductive routes of the same electrode, even when one of the conductive routes is cut off, the other conductive route is alive (for example, In the case of being interrupted at point A of the support portion 3a shown in FIG. 9, a voltage is applied to the excitation electrode via the other support portion 3b), so that normal vibration characteristics are obtained and the shipping test is passed. May end up. However, since the blocked conductive route is caused by the lack of the support portion, there is a possibility that a defect may occur after shipping or the service life may be shortened.

  This problem is the same even in the case of the contour vibration type piezoelectric vibrator by the width-length / length-length coupled mode. In the case of the piezoelectric vibrator 11 in the width-longitudinal-longitudinal coupling mode, as shown in FIG. 10, electrode patterns that are electrically connected to the excitation electrodes 15a and 15b are formed on the front and back surfaces of the support portions 13 and 16, respectively. However, even if either of the pair of arm portions 13a and 13b is damaged in the support portion 13 or one of the pair of arm portions 16a and 16b is damaged in the support portion 16, A voltage is supplied to the excitation electrodes 15a and 15b. For example, even when a defect occurs in the arm portion 13b at the point B shown in FIG. 10, a voltage is supplied from the one arm portion 13a to the excitation electrode 15a. For this reason, the vibration unit 12 may normally excite predetermined vibrations and pass the shipping test. However, since the support portion 13 has a structural defect, there is a risk of causing a defect after the product is shipped.

  Such mechanical troubles such as breakage of the support portion have no effective means other than finally relying on human visual observation.

  Accordingly, an object of the present invention is to identify a defective portion by supporting a vibrating portion on which an excitation electrode is formed and electrically detecting a mechanical or structural failure of a supporting portion serving as a voltage supply route. It is also possible to provide a piezoelectric vibrator having an electrode structure that can reliably and easily select good and defective products at the time of product shipment.

In order to solve the above-mentioned problem, the piezoelectric vibrator of the present invention is formed on a vibration part in which three or more excitation electrodes are formed, a plurality of support parts that support the vibration part, and these support parts. A piezoelectric vibrator comprising three or more electrode patterns electrically connected to the excitation electrode and a terminal electrode for applying a voltage to the excitation electrode through the electrode pattern, wherein at least three excitation electrodes each include the plurality of the excitation electrodes. And directly connecting to at least three electrode patterns formed on the support portion, and having a portion where excitation electrodes of the same polarity are not connected to each other in the vibration portion, the at least three excitation electrodes pass through only the electrode patterns. Conductive with the terminal electrode .

According to another piezoelectric vibrator of the present invention, the three or more excitation electrodes are formed on the front surface and the back surface of the vibration portion and are not directly connected to the electrode pattern formed on the support portion. Including an excitation electrode connected to the electrode pattern on one surface of the vibration part, and a side electrode pattern in which an excitation electrode of the same polarity not directly connected to the electrode pattern on the other surface of the vibration part goes around the side surface of the vibration part It is connected .

Further, in another piezoelectric vibrator of the present invention, the vibration part has vibration nodes at four corners, and the four corners of the vibration part are supported by four support parts via the vibration nodes, and are provided on the front and back surfaces of the vibration part. Excitation electrodes having different polarities are alternately arranged on at least three surfaces, and electrode patterns formed on the four support portions are formed on the front and back surfaces of the vibration portion. One excitation electrode connected directly to one excitation electrode, while being connected to the electrode pattern on one surface of the vibration part, and the same polarity excitation electrode not directly connected to the electrode pattern on the other surface of the vibration part Are connected by a side electrode pattern that goes around the side surface of the vibration part .

In addition, another piezoelectric vibrator of the present invention has a vibration part in which a pair of excitation electrodes having different polarities are formed on the front surface and the back surface, and one end of two opposite sides of the vibration part as a node. A piezoelectric vibrator comprising a pair of bent support portions extending outward and terminal electrodes for applying a voltage having a polarity corresponding to each excitation electrode through electrode patterns respectively formed on the pair of support portions. , between the terminal electrodes corresponding to the excitation electrode she is characterized by being connected by a continuous electrode pattern of one system that are routed over the entire length of the support portions.

In addition, another piezoelectric vibrator of the present invention includes a vibrating portion having a pair of excitation electrodes formed on the front surface and the back surface, and an arm portion branched outwardly from one end of two opposite sides of the vibrating portion. a supporting portion closed loop shaped bent portion is formed by a pair of terminal electrodes for applying a voltage having a polarity corresponding to the respective excitation electrodes via said surface and the electrode pattern formed on the rear surface of the support portion In the piezoelectric vibrator having the above structure, a continuous electrode pattern of one system along the whole bent portion is formed on the front and back surfaces of the support portion by folding back between the respective arm portions. It is characterized by.

  According to the piezoelectric vibrator of the present invention, the structural defect of the support part that supports the vibration part is discovered by inspecting the capacitance change of the excitation electrode part formed in the vibration part that causes the contour vibration. Therefore, it is possible to reliably and promptly select non-defective / defective products at the time of product shipment.

  Hereinafter, the structure of the piezoelectric vibrator of the present invention will be described using a contour vibration type crystal vibrator as an example. Here, FIGS. 1 to 3 show a lame mode crystal resonator, and FIGS. 4 to 6 show a width-longitudinal length coupled mode crystal resonator.

  The crystal resonator 20 shown in FIGS. 1 to 3 has a structure for generating a lame mode vibration. The crystal unit 20 in the lame mode rotates the Y plate made of the XZ plane of the rough quartz stone around the X axis in the range of −40 ° to −60 °, or 30 ° to 40 °, and further this rotation. The XZ ′ plane (Y ′ plate) obtained in the above is punched into a shape obtained by plane rotation in the range of 40 ° to 50 °, and separated into a vibrating portion 21 and a frame portion 24 that supports the vibrating portion 21. Is done. FIG. 1A shows the front surface of the crystal unit 20, and FIG. 1B shows the back surface. The crystal resonator 20 of this embodiment includes a rectangular vibration part 21 having vibration nodes 22a, 22b, 22c, and 22d at four corners, and support parts 23a and 23b extending outward from the four nodes 22a to 22d. , 23c, 23d, and a frame portion 24 which is on the outer periphery of the vibration portion 21 and is supported via the support portions 23a to 23d.

  Exciting electrodes are formed on both the front and back surfaces of the vibration part 21, and each side is bent and deformed with the nodes 22 a to 22 d as fulcrums by applying electric fields of opposite phases from the frame part 24, thereby generating a lame mode vibration. . In the crystal resonator 20 of the present embodiment, in order to generate the (3, 1) -order lame mode vibration, excitation electrodes for generating the lame mode vibration are formed in three rows and columns on both the front and back surfaces of the vibration unit 21. .

  Terminal electrodes 24a and 24b are formed on the front surface and the back surface of the frame portion 24 facing each other with the vibration portion 21 interposed therebetween. One terminal electrode 24a is connected to the excitation electrodes 27a and 27b through the support portion 23d, and the excitation electrode 27c is connected through the support portion 23c. The other terminal electrode 24b is connected to the excitation electrodes 28a and 28b through the support portion 23a, and the excitation electrode 28c is connected through the support portion 23b. The excitation electrodes 27a and 27b and the excitation electrodes 28a and 28b are electrically connected by side electrode patterns 25 and 26 provided along the side surface of the vibration part 21, as shown in FIG.

  Thus, each excitation electrode (27a-27c, 28a-28c) formed in the surface and the back surface of the vibration part 21 is electrically connected via one of the four support parts (23a-23d). Will be connected. For example, as shown in FIG. 3, if the point C on the support portion 23a is damaged for some reason, no voltage is supplied from the terminal electrode 24b to the excitation electrodes 28a and 28b. For this reason, the capacitance changes in the region of the excitation electrodes 28a and 28b. Although description is omitted, the capacitance in the region where the excitation electrodes that conduct each other are changed even when any of the other support portions 23b to 23d is damaged.

  For this reason, in the shipping test for checking the function of the crystal unit 20, when the capacitance value of the vibration unit 21 is measured, if there is an excitation region where the capacitance value is outside the reference value or cannot be detected. Thus, it can be easily confirmed that a defect has occurred in the electrode pattern leading to the excitation electrode region, particularly the electrode pattern formed on the corresponding support portion, and the structural defect of the crystal unit 20 can be detected early. It will be possible to discover.

  Next, a piezoelectric vibrator (quartz crystal vibrator) according to a second embodiment of the present invention will be described. This crystal oscillator is accompanied by the same contour vibration as the above-mentioned lame mode, and has a structure for generating vibration in the width-length / length-length coupled mode.

  A crystal resonator 30 shown in FIG. 4 rotates a Y plate made of an XZ plane of a rough quartz crystal around the X axis in a range of 40 ° to 60 °, and further, an XZ ′ plane (Y ′) obtained by this rotation. It is a crystal resonator formed by rotating a plate) in a range of 40 ° to 50 °. A typical example of this quartz substrate is an NS-GT cut substrate.

  The quartz crystal resonator 30 is formed by punching the quartz crystal substrate. As shown in FIGS. 4A and 4B, the quartz resonator 30 is formed from a rectangular vibrating portion 31 and an outer periphery of the vibrating portion 31. It is formed by a pair of support portions 33 and 36 that bend and extend outward, and one end of each of the support portions 33 and 36 is connected to terminal electrodes 34a and 34b provided in a casing (not shown).

  Excitation electrodes 37a and 37b are formed on both the front and back surfaces of the vibration unit 31, and each outer periphery is bent by applying reverse-phase voltages from the terminal electrodes 34a and 34b through the support units 33 and 36, respectively. Deforms to generate vibration in the width-length / length-length coupled mode.

  The support portions 33 and 36 buffer the vibration generated in the vibration portion 31 so as not to leak to the outside, and in order not to increase the equivalent series resistance value, in a range that does not affect the strength and stability, It is preferable to form it long and thin. For this reason, as shown in FIGS. 4 (a) and 4 (b), the intermediate portion is formed to have a predetermined length by projecting in the left-right direction. One support portion 33 includes a lead portion 33c connected to the vibrating portion 31, a lead portion 33d connected to the terminal electrode 34a, and a pair of arm portions 33a bulging outwardly between the lead portions 33c and 33d. , 33b. The other support portion 36 includes a lead portion 36c connected to the vibrating portion 31, a lead portion 36d connected to the terminal electrode 34b, and a pair of arm portions 36a bulging outwardly between the lead portions 36c and 36d. , 36b. Since the support portions 33 and 36 support the vibration portion 31 while absorbing the vibration, the support portions 33 and 36 are thin and long. In addition, since the vibrating portion 31 is supported in a well-balanced manner and is housed in a small casing, and is also a route for supplying voltage, as shown in FIG. 4, the pair of arm portions 33a and 33b. The arm portions 36a and 36b are formed substantially symmetrically. The electrode patterns 38 and 39 are formed on the entire front surface or back surface of the support portions 33 and 36.

  The pair of arm portions 33a and 33b branched from the lead-out portions 33c and 33d are formed in a symmetrical U-shape. An electrode pattern 38 for connecting the excitation electrode 37a and the terminal electrode 34a is formed on the surface of the support portion 33 integrally formed by the pair of arm portions 33a and 33b and the lead portions 33c and 33d. As shown in FIG. 5, this electrode pattern 38 is formed by a continuous line of conductive lines extending from the terminal electrode 34a to the lead portion 33c to the arm portion 33a to the arm portion 33b to the lead portion 33d to the excitation electrode 37a. Yes. In order to route such a series of continuous conductive lines, after wiring once along the arm portion 33a, it is folded back at the folded portion 38a near the joint portion of the lead portion 33d to the vicinity of the joint portion of the lead portion 33c. Returning, it is formed by being routed along the arm portion 33b as it is. Further, as shown in FIG. 4 (b), the electrode pattern 39 on the back surface side is a continuous line extending from the terminal electrode 34b to the lead portion 36c to the arm portion 36a to the arm portion 36b to the lead portion 36d to the excitation electrode 37b. The conductive line is formed. In order to route such a series of continuous electrode patterns 39, after wiring once along the arm portion 36a, it is folded back in the vicinity of the joint portion of the lead portion 36d and returned to the vicinity of the joint portion of the lead portion 36c. It is formed so as to extend to the portion 36b.

  When one of the arm portions 33a and 33b or the lead-out portions 33c and 33d (for example, point D) is damaged by the routing of the electrode pattern 38 over the entire circumference, as shown in FIG. The voltage from the terminal electrode 34a is not supplied to the excitation electrode 37a. Therefore, when the measured capacitance value of the excitation electrode 37a is out of the reference value or cannot be detected in the shipping test of the crystal unit 30, the excitation electrode 37a or the electrode pattern connected to the excitation electrode 37a is used. Since it can be predicted that there are 38 defects, structural defects such as the arm portions 33a and 33b forming the support portion 33 on which the electrode pattern 38 is disposed can be confirmed at an early stage. For this reason, it is possible to more reliably select a non-defective product or a defective product, and to suppress the defective product from being marketed. Although explanation is omitted, when the support portion 36 shown in FIG. 4B is damaged, the vibration of the excitation electrode 37b is affected.

  FIG. 7 shows a crystal resonator 40 in a width-longitudinal length-coupled mode having an electrode pattern by routing other than the above. The quartz crystal vibrator 40 vibrates via a straight electrode pattern 48a, 48b continuous from the pair of terminal electrodes 44a, 44b to the front surface (a), side surface (b) and back surface (c) of the support portions 43, 46. Conduction with the respective excitation electrodes 47a and 47b formed on the front surface and the back surface of the portion 41 is achieved. Thus, since the electrode patterns 48a and 48b are formed over the entire circumference of the support portions 43 and 46, when a part of the electrode patterns 48a and 48b is damaged, the capacitance of the diaphragm 41 changes. Appears and structural defects can be detected early.

  FIG. 8 shows an example of electrode pattern formation in the width-longitudinal crystal resonator 50. The width-longitudinal crystal resonator 50 is supported by a frame portion 52 provided with terminal electrodes 54 a and 54 b by a pair of support portions 53 and 56 extending from the longitudinal direction of the rectangular vibration portion 51. The excitation electrode 57a provided on the surface (a) of the vibration part 51 is formed through the surface of the support part 56 over the surface (a), side face (b) and back face (c) of the frame part 52. Conduction is achieved by 58a. The excitation electrode 57b provided on the back surface (c) of the vibration part 51 is an electrode formed on the back surface (c), side surface (b), and front surface (a) of the frame part 52 through the back surface of the support part 53. Conduction is achieved by the pattern 58b. Thus, since the electrode patterns 58a and 58b communicating with the excitation electrodes 57a and 57b are provided corresponding to either the front surface or the back surface of the support portions 53 and 56, any one of the support portions 53 and 56 is provided. If one of them is damaged, the vibration of the vibration unit 51 will be affected, and the failure location can be easily identified.

  In this embodiment, the contour vibration type piezoelectric vibrator represented by the lame mode and the width longitudinal / length longitudinal coupling mode has been described as an example. However, the present invention is limited to such a contour vibration type piezoelectric vibrator. As long as the structure has a connection with an electrode pattern such as a vibrating part on which an excitation electrode is formed and a support part that supports the vibrating part, the piezoelectric vibrator can be applied to any vibration mode. Is possible.

It is a top view which shows the surface (a) and back surface (b) of the piezoelectric vibrator of 1st Embodiment which concerns on this invention. It is a side view of the vibration part of the piezoelectric vibrator. In the piezoelectric vibrator of the said 1st Embodiment, it is an effect | action figure which shows the state of the excitation electrode when one of the support parts is damaged. It is a top view which shows the surface (a) and back surface (b) of the piezoelectric vibrator of 2nd Embodiment which concerns on this invention. It is a figure which shows the example of formation of the electrode pattern formed in the support part of the said piezoelectric vibrator. In the piezoelectric vibrator of the said 2nd Embodiment, it is an action figure which shows the state of the excitation electrode when one of the support parts is damaged. It is a top view which shows the example of formation of the other electrode pattern in the width-length / length-length coupling mode piezoelectric vibrator. It is a top view which shows the example of formation of the electrode pattern in a width longitudinal vibrator. It is a top view which shows the surface (a) and back surface (b) of the conventional lame mode piezoelectric vibrator. It is a top view which shows the surface (a) and back surface (b) of the conventional width longitudinal-length longitudinal coupling mode piezoelectric vibrator.

Explanation of symbols

20, 30, 40, 50 Crystal resonator (piezoelectric resonator)
21, 31 Vibration part 23a-23d Support part 24a, 24b Terminal electrode 27a-27c Excitation electrode 28a-28c Excitation electrode 33, 36 Support part 34a, 34b Terminal electrode 37a, 37b Excitation electrode

Claims (5)

A vibrating part on which three or more excitation electrodes are formed;
A plurality of support parts for supporting the vibration part ;
Three or more electrode patterns formed on these support portions and electrically connected to the excitation electrode ;
A piezoelectric vibrator comprising a terminal electrode for applying a voltage to the excitation electrode through this electrode pattern ,
Each of the at least three excitation electrodes is directly connected to at least three electrode patterns formed on the plurality of support portions, respectively, and has a portion where excitation electrodes having the same polarity are not connected to each other in the vibration portion, A piezoelectric vibrator, wherein at least three excitation electrodes are electrically connected to the terminal electrode only through each electrode pattern . The three or more excitation electrodes include excitation electrodes that are formed on the front and back surfaces of the vibration part and are not directly connected to the electrode pattern formed on the support part,
The excitation electrode connected to the electrode pattern on one surface of the vibration part and the excitation electrode of the same polarity that is not directly connected to the electrode pattern on the other surface of the vibration part are connected by a side electrode pattern that wraps around the side surface of the vibration part. The piezoelectric vibrator according to claim 1 . The vibration part has vibration nodes at four corners, and the four corners of the vibration part are supported by four support parts via the vibration nodes, and at least three excitation electrodes of different polarities are alternately arranged on the front and back surfaces of the vibration part. The above is arranged on each surface, and the electrode patterns respectively formed on the four support portions are directly connected to the two excitation electrodes on each surface formed on the front surface and the back surface of the vibration portion,
On the other hand, one excitation electrode connected to the electrode pattern on one surface of the vibration part, and a side electrode in which an excitation electrode of the same polarity not directly connected to the electrode pattern on the other surface of the vibration part goes around the side surface of the vibration part The piezoelectric vibrator according to claim 2, which is connected by a pattern . A vibrating portion in which a pair of excitation electrodes having different polarities are formed on the front surface and the back surface ;
One end of the two opposite sides of the vibrating portion is a node, and a pair of bent support portions extending outward from the node,
In a piezoelectric vibrator comprising terminal electrodes for applying a voltage having a polarity corresponding to each excitation electrode through an electrode pattern formed on each of the pair of support portions,
The piezoelectric vibrator is characterized in that the excitation electrode and the corresponding terminal electrode are connected by a series of continuous electrode patterns drawn over the entire length of each support portion . A vibrating part in which a pair of excitation electrodes are formed on the front and back surfaces, and a support part in which a closed loop-shaped bent part is formed by the branched arm part extending outward from one end of two opposite sides of the vibrating part. When, in the piezoelectric vibrator having a pair of terminals electrodes for applying a surface and the polarity of the voltage corresponding to the respective excitation electrode through said electrode patterns formed on the back surface of the support portion,
A piezoelectric vibrator characterized in that a series of continuous electrode patterns along the entire bent portion are formed on the front and back surfaces of the support portion by folding back between the respective arm portions.

Images