JP2011097369A - Crystal oscillation element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the generation of unnecessary oscillation and to improve a CI value. <P>SOLUTION: Projection parts are provided on both main surfaces of a planar crystal piece, one projection part is defined as a first projection part, the other projection part is defined as a second projection part, and the crystal oscillation element includes a first electrode provided on the first projection part and a second electrode provided on the second projection part. The crystal oscillation element is formed such that the surface area of the first projection part is smaller than the surface area of the second projection part, the surface area of the first electrode and the surface area of the second electrode are different, and the surface area of the first electrode and the surface area of the second electrode are smaller than the surface area of the first projection part. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a crystal resonator element used in an electronic device.

  Conventionally, for example, crystal resonators have been used in electronic devices. As an example of the conventional crystal resonator, it is mainly composed of an element mounting member, a crystal vibration element, and a lid member. The crystal vibration element is mounted in a recess provided in the element mounting member and hermetically sealed by the lid member. A stopped structure is known. Here, in the crystal resonator element, excitation electrodes are formed on both main surfaces of the crystal piece. The element mounting member is provided with a mounting pad for mounting the crystal resonator element in the recess. The lid member is a flat metal plate and is joined to the element mounting member in order to hermetically seal the recess. Moreover, for example, sealing using Au—Sn, sealing by seam welding, or the like is used for sealing the concave portion provided in the element mounting member.

Various shapes have been proposed for the crystal piece formed in the crystal resonator element.
For example, as a flat-plate type crystal piece, there are known a rectangular shape in plan view (see, for example, Patent Document 1) and a circular shape in plan view (see, for example, Patent Document 2). As the crystal piece, for example, a tuning fork shape (see, for example, Patent Document 3) is known. The flat element has a structure in which a convex portion is provided on the main surface and an electrode is provided on the main surface of the convex portion (see, for example, Patent Document 4), or a concave portion is provided. A structure having an electrode on the surface has been proposed (for example, see Patent Document 5).
These electrodes are electrically connected to the routing pattern, and are routed to the end of the crystal piece by this routing pattern.

Such a crystal piece having a square shape in plan view, a crystal piece having a circular shape in plan view, and a crystal piece having a tuning fork shape are formed from a crystal wafer.
For example, in the case of a crystal resonator element having a structure in which a convex portion is formed on the main surface of a quartz piece having a square shape in plan view, the main surface of the convex portion has a predetermined area and is formed in a quadrangular shape in plan view. This convex portion is formed by wet etching or the like.
An electrode is formed on the main surface of the convex portion, and an electrode is also provided on the opposite side so as to face the electrode, thereby forming a crystal resonator element (see, for example, Patent Document 4).
In addition, a convex part may be formed in only one main surface of a crystal piece, and may be formed in both main surfaces. In the crystal resonator element having such a shape, the thickness of the electrode is also considered as a convex portion, and is handled as a multistage convex portion together with the convex portion of the crystal piece.
The reason for providing such a convex portion is to allow the vibration energy of the crystal resonator element to be confined within the convex portion. As a result, it can be expected that an excellent characteristic having a crystal impedance (hereinafter referred to as “CI value”) lower than that of the flat plate-like crystal resonator element.
A low CI value can be said to be a state in which vibration energy is confined in the convex portion while being stable vibration.
Further, as other examples of elements intended to confine vibration energy, a convex-processed crystal piece and a bevel-processed crystal piece have been proposed (see, for example, Patent Document 6).

JP 2003-142975 A JP 2005-197801 A JP 2004-205426 A JP 2007-053820 A JP 2004-088137 A JP 2007-013571 A

However, the conventional crystal resonator element for the purpose of energy confinement may cause a boundary at the end portion of the convex portion and generate unnecessary vibration depending on the height of the convex portion.
For example, the unnecessary vibration is generated from a portion that becomes an outline of a crystal piece. As a result, in the crystal resonator element having multi-stage convex portions, unnecessary vibration is generated by the contour of the crystal piece, the contour of the convex portion provided on the crystal piece, and the contour of the electrode provided on the convex portion. . When this unnecessary vibration is eliminated, the CI value is lowered and excellent characteristics can be obtained. For this reason, the conventional crystal resonator element is formed by adjusting the height and the surface area in the width direction of the multi-stage convex portions in order to reduce this unnecessary vibration.
As a result, the conventional crystal resonator element reduces unnecessary vibration and improves the energy confinement of vibration, but it takes much time to form the crystal resonator element in an optimum state.

  Accordingly, an object of the present invention is to provide a crystal resonator element that solves the above-described problems, reduces the occurrence of unnecessary vibration, and improves the CI value.

  In order to solve the above problems, the present invention has convex portions on both main surfaces of a plate-shaped crystal piece, one convex portion as a first convex portion, and the other convex portion as a second convex portion, A crystal resonator element comprising a first electrode provided on the first convex portion and a second electrode provided on the second convex portion, wherein the surface area of the first convex portion is It is characterized by being provided smaller than the surface area of the second convex part.

  Further, the present invention provides a convex portion on both main surfaces of the plate-shaped crystal piece, wherein one convex portion is a first convex portion and the other convex portion is a second convex portion, and the first convex portion A quartz-crystal vibrating element comprising a first electrode provided at a part and a second electrode provided at the second convex part, wherein the surface area of the first convex part is the second convex part. Smaller than the surface area of the first electrode, the surface area of the first electrode is smaller than the surface area of the second electrode, the first electrode is provided on the entire main surface of the first convex portion, and the second electrode The electrode is configured to be provided on the entire main surface of the second convex portion.

  Further, the present invention is a crystal resonator element using the crystal piece whose plane is parallel to the X-axis and the Z-axis, and when the reference direction of the length is the X-axis direction or the Z-axis direction, the crystal The X-axis of the second electrode provided on both ends of the length of the X-axis direction or the Z-axis direction of the piece, the planar center of the first electrode, and the entire main surface of the second convex portion Both ends of the length in the direction or the Z-axis direction are located on the outline of a predetermined circle.

  Further, the present invention provides a convex portion on both main surfaces of the plate-shaped crystal piece, wherein one convex portion is a first convex portion and the other convex portion is a second convex portion, and the first convex portion A quartz-crystal vibrating element comprising a first electrode provided at a part and a second electrode provided at the second convex part, wherein the surface area of the first convex part is the second convex part. A surface area of the first electrode is smaller than a surface area of the second electrode, and a surface area of the second electrode is larger than a surface area of the first convex portion. It is characterized by.

  Further, the present invention provides a convex portion on both main surfaces of the plate-shaped crystal piece, wherein one convex portion is a first convex portion and the other convex portion is a second convex portion, and the first convex portion A quartz-crystal vibrating element comprising a first electrode provided at a part and a second electrode provided at the second convex part, wherein the surface area of the first convex part is the second convex part. The surface area of the first electrode and the surface area of the second electrode are different from each other, and the surface area of the first electrode and the surface area of the second electrode are different from each other. It is characterized by being formed to be smaller than the surface area of the convex portion.

  Further, the present invention is a crystal resonator element using the crystal piece whose plane is parallel to the X-axis and the Z-axis, and when the reference direction of the length is the X-axis direction or the Z-axis direction, the crystal Both ends of the length in the X-axis direction or Z-axis direction of the piece, both ends of the length in the X-axis direction or Z-axis direction of the first protrusion, the plane center of the first electrode, Both ends of the length of the second convex portion in the X-axis direction or Z-axis direction, and both ends of the length of the second electrode corresponding to the X-axis direction or Z-axis direction of the crystal piece, It is located on the outline of a predetermined circle.

  Further, according to the present invention, the shape of the crystal piece, the shape of the first convex portion, the shape of the second convex portion, the shape of the crystal piece, and the shape of the crystal piece are predetermined. It is characterized by an ellipsoidal shape.

  According to such a crystal resonator element, since the surface area of the first convex portion is smaller than the surface area of the second convex portion, it becomes a crystal piece with a pseudo convex structure, and the contour of the crystal piece Unnecessary vibrations are less likely to occur in the portion, the contour portion of the first convex portion, and the contour portion of the second convex portion, and the CI value can be improved.

  According to such a crystal resonator element, the surface area of the first protrusion is smaller than the surface area of the second protrusion, and the surface area of the first electrode is smaller than the surface area of the second electrode. Since the first electrode is provided on the entire main surface of the first convex portion and the second electrode is provided on the entire main surface of the second convex portion, it is pseudo. A crystal piece with a convex structure is formed, and unnecessary vibrations are less likely to occur in the contour portion of the crystal piece, the contour portion of the first convex portion, and the contour portion of the second convex portion, and the CI value can be improved.

  Further, according to such a crystal resonator element, both ends of the crystal piece in the X-axis direction or the Z-axis direction, the plane center of the first electrode, and the main surface of the second convex portion Since both ends of the length of the second electrode provided on the entire surface in the X-axis direction or the Z-axis direction are located on the outline of a predetermined circle, a pseudo-convex crystal piece is obtained. The contour portion of the crystal piece, the contour portion of the first convex portion, and the contour portion of the second convex portion have a shape that makes it difficult to generate unnecessary vibration, and the CI value can be improved.

  According to such a crystal resonator element, the surface area of the first protrusion is smaller than the surface area of the second protrusion, and the surface area of the first electrode is smaller than the surface area of the second electrode. Since the surface area of the second electrode is smaller than the surface area of the first convex part, it becomes a crystal piece with a pseudo convex structure, and the contour part of the crystal piece, the first convex part Unnecessary vibration is less likely to occur at the contour portion of the second convex portion and the contour portion of the second convex portion, and the CI value can be improved.

  According to such a crystal resonator element, the surface area of the first convex portion is smaller than the surface area of the second convex portion, and the surface area of the first electrode and the surface area of the second electrode are different. In addition, since the surface area of the first electrode and the surface area of the second electrode are formed to be smaller than the surface area of the first convex portion, a crystal piece having a pseudo convex structure is obtained. Unnecessary vibration is less likely to occur in the contour portion of the first convex portion, the contour portion of the first convex portion, and the contour portion of the second convex portion, and the CI value can be improved.

  Further, according to such a crystal resonator element, both end portions of the crystal piece in the X-axis direction or Z-axis direction length and both ends of the first convex portion in the X-axis direction or Z-axis direction length Corresponding to the X-axis direction or the Z-axis direction of the quartz crystal piece, the center of the plane of the first electrode, both ends of the length of the second convex portion in the X-axis direction or the Z-axis direction, The both ends of the length of the second electrode are positioned on the contour of a predetermined circle, thereby forming a pseudo-convex crystal piece, the contour portion of the crystal piece, the contour of the first convex portion It becomes a shape which makes it difficult to generate unnecessary vibration at the contour portion of the portion and the second convex portion, and the CI value can be improved.

  According to such a crystal resonator element, the shape of the crystal piece, the shape of the first protrusion, the shape of the second protrusion, the shape of the crystal piece, and the shape of the crystal piece And has a predetermined ellipse shape

An example of the crystal oscillation element which concerns on 1st embodiment or 2nd embodiment of this invention is shown, (a) is the side view which showed notionally the length of the X-axis direction, (b) is the 1st. It is the perspective view seen from the one electrode side, (c) is the perspective view seen from the 2nd electrode side. An example of the crystal oscillation element which concerns on 3rd embodiment of this invention is shown, (a) is the side view which showed notionally the length of a X-axis direction, (b) is seen from the 1st electrode side. (C) is the perspective view seen from the 2nd electrode side. It is the side view which showed the modification of the crystal oscillation element which concerns on 3rd embodiment of this invention. It is a side view which shows an example of the crystal vibration element which concerns on 4th embodiment of this invention. An example of the crystal oscillation element which concerns on the modification of this invention is shown, (a) is the perspective view seen from the 1st electrode side, (b) is the perspective view seen from the 2nd electrode side. 2 is a simulation photograph of the crystal resonator element of Example 1. FIG. 6 is a simulation photograph of the crystal resonator element of Comparative Example 1. 6 is a simulation photograph of the crystal resonator element of Comparative Example 2.

  Next, the best mode for carrying out the present invention (hereinafter referred to as “embodiment”) will be described in detail with reference to the drawings as appropriate. Note that each component is exaggerated for easy understanding of the state.

(First embodiment)
As shown in FIGS. 1A to 1C, a crystal resonator element 100a according to a first embodiment of the present invention includes a crystal piece 10a having convex portions 11a and 11b on both main surfaces, and the convex portion It is mainly composed of electrodes 12a and 12b provided on the main surfaces of the portions 11a and 11b.

  The crystal piece 10a is AT cut and is formed in an ellipse shape. Here, when the convex portion provided on one main surface is the first convex portion 11a and the convex portion provided on the other main surface is the second convex portion 11b, the first convex portion 11a is: It is formed smaller than the second convex portion 11b. That is, the surface area of the main surface of the first convex portion 11a is formed smaller than the surface area of the main surface of the second convex portion 11b. The first convex portion 11a and the second convex portion 11b are formed such that the planar shape of the main surface is an ellipse.

  The crystal piece 10a has a plane parallel to the X axis and the Z axis. Here, for example, in the case of AT cut, a case where the Z axis is rotated at a predetermined angle and used as a new Z ′ axis is also included in the Z axis.

Electrodes 12a and 12b are provided on the main surface of the first convex portion 11a and the main surface of the second convex portion 11b. In addition, the electrode provided in the main surface of the 1st convex part 11a is set as the 1st electrode 12a, and the electrode provided in the main surface of the 2nd convex part 11b is set as the 2nd electrode 12b.
The first electrode 12a is provided on the entire main surface of the first convex portion 11a. The second electrode 12b is provided on the entire main surface of the second convex portion 11b.
In addition, as long as these 1st electrodes 12a and 2nd electrode 12b are formed in the main surface of a convex part in the range with which the said state is satisfy | filled, you may set the length arbitrarily.

  As described above, the crystal resonator element 100a according to the first embodiment of the present invention is configured so that the surface area of the first convex portion 11a is smaller than the surface area of the second convex portion 11b. This is a crystal piece with a convex structure, and the CI value is set so that unnecessary vibrations are less likely to occur in the contour portion of the crystal piece, the contour portion of the first convex portion, and the contour portion of the second convex portion, and the CI value becomes low. Can be improved.

(Second embodiment)
Next, a crystal resonator element according to a second embodiment of the present invention will be described using the same piezoelectric resonator element as in the first embodiment.
As shown in FIGS. 1A to 1C, a crystal resonator element 100a according to a second embodiment of the present invention includes a crystal piece 10a having convex portions 11a and 11b on both main surfaces, and the convex portion It is mainly composed of electrodes 12a and 12b provided on the main surfaces of the portions 11a and 11b.

  The crystal piece 10a is AT cut and is formed in an ellipse shape. Here, when the convex portion provided on one main surface is the first convex portion 11a and the convex portion provided on the other main surface is the second convex portion 11b, the first convex portion 11a is: It is formed smaller than the second convex portion 11b. That is, the surface area of the main surface of the first convex portion 11a is formed smaller than the surface area of the main surface of the second convex portion 11b. The first convex portion 11a and the second convex portion 11b are formed such that the planar shape of the main surface is an ellipse.

Electrodes 12a and 12b are provided on the main surface of the first convex portion 11a and the main surface of the second convex portion 11b. In addition, the electrode provided in the main surface of the 1st convex part 11a is set as the 1st electrode 12a, and the electrode provided in the main surface of the 2nd convex part 11b is set as the 2nd electrode 12b.
The first electrode 12a is provided on the entire main surface of the first convex portion 11a. The second electrode 12b is provided on the entire main surface of the second convex portion 11b.
At this time, the first electrode 12a is provided smaller than the second electrode 12b. That is, the surface area of the first electrode 12a is set smaller than the surface area of the second electrode 12b. The first electrode 12a and the second electrode 12b are formed in an elliptical shape in plan view.

  Here, the relationship among the lengths of the first convex portion 11a, the second convex portion 11b, the first electrode 12a, and the second electrode 12b will be described. The X-axis direction of the AT-cut crystal piece 10a is defined as a reference direction of length. At this time, each length is the length of the ellipse-shaped major axis, that is, the major axis. Further, the Z-axis direction may be used as the reference direction for the length. In this case, for example, the Z-axis direction is the minor axis direction of the ellipse.

  First, the length L1 of the crystal piece 10a in the X-axis direction is determined in advance. At this time, the end portions P1a and P1b having the length L1 in the X-axis direction of one main surface of the crystal piece 10a are in a state of being positioned on the contour of a virtual circle having a predetermined radius R1. In this state, the center of the length L2 of the first electrode 12a, that is, the point P2 at the center of the plane is in a state of being located on the contour of the circle having the predetermined radius R1.

In other words, the length L1 of the crystal piece 10a is a length in which both end portions P1a and P1b of one main surface of the length L1 are positioned on the contour of a circle having a predetermined radius R1. The length L1 of the crystal piece 10a is determined in advance.
Further, the first electrode 12a has a length on the contour of the circle having the predetermined radius R1 from a position away from the crystal piece 10a in consideration of the thickness of the first convex portion 11a and the first electrode 12a. The center point P2 of L2, that is, the plane center is located.

  Further, in the length L1 of the crystal piece 10a, the end portions P3a and P3b of the other main surface of the crystal piece 10a in the X-axis direction have a predetermined size different from the circle having the predetermined radius R1. It is in the state located on the outline of the virtual circle of radius R2. In this state, both ends P4a and P4b of the length L3 of the second electrode 12b are in a state of being located on the contour of a circle having a predetermined radius R2.

In other words, the length L1 of the crystal piece 10a is a length in which both ends P3a and P3b of the other main surface of the length L1 are positioned on the contour of a circle having a predetermined radius R1.
In addition, the second electrode 12b has a length L3 on the contour of the circle having the predetermined radius R2 from a position away from the crystal piece 10a in consideration of the thickness of the first recess 11b and the first electrode 12b. It is set as the length which located both ends P4a and P4b.
Thereby, the length of the 1st convex part 11a is the same as the length of the 1st electrode 12a. Similarly, the length of the second convex portion 11b is the same as the length of the second electrode 12b.

Note that the thickness of the first electrode 12a is a thickness converted to the density of crystal.
As a result, the center point P2 of the plane of the first electrode 12a is in contact with the contour of the circle having the predetermined radius R1. Therefore, the actual thickness of the first electrode 12a is a value different from the thickness when it is positioned on the contour of the circle having the predetermined radius R1.
Similarly, the thickness of the second electrode 12b is a thickness converted to the density of quartz when positioned on the contour of the circle having the predetermined radius R2. Therefore, the actual thickness of the second electrode 12b is a value different from the thickness when positioned on the contour of the circle having the predetermined radius R2.
The radius R1 and the radius R2 may be the same size.

  Therefore, in the crystal resonator element 100a according to the second embodiment of the present invention, the surface area of the first protrusion 11a is smaller than the surface area of the second protrusion 11b, and the surface area of the first electrode 12a. Can be made smaller than the surface area of the second electrode 12b.

  In addition, the length of the short diameter of the 1st convex part 11a is the distance from the edge part of the length of the 1st convex part 11a to the edge part (for example, edge part P1a) of the length of the crystal piece 10a, for example. It is determined so as to be secured even on the short diameter side of the crystal piece 10a.

  Since the crystal resonator element 100a according to the second embodiment of the present invention is configured as described above, the surface area of the first protrusion 11a is smaller than the surface area of the second protrusion 11b, and the surface area of the first electrode 12a. Is smaller than the surface area of the second electrode 12b, the first electrode 12a is provided on the entire main surface of the first convex portion 11a, and the second electrode 12b is provided on the entire main surface of the second convex portion 11b. Since it is configured, it becomes a quartz piece with a pseudo convex structure, and it is difficult for unnecessary vibrations to occur in the outline part of the crystal piece 10a, the outline part of the first electrode 12a, and the outline part of the second electrode 12b, The CI value can be improved so as to obtain a low CI value. Can be improved.

  Further, according to such a crystal resonator element 100a, the crystal piece 10a is provided on the entire principal surface of the first protrusion 11a and both ends P1a, P1b, P3a, P3b of the length L1 in the X-axis direction. Both ends P2a, P2b of the length L2 in the X-axis direction of the first electrode 12a and both ends of the length L3 in the X-axis direction of the second electrode 12b provided on the entire main surface of the second protrusion 11b Since the parts P4a and P4b are located on the outline of a predetermined circle, it becomes a shape that makes it difficult to generate unnecessary vibration, and the CI value can be improved.

(Third embodiment)
Next, a crystal resonator element according to a third embodiment of the invention will be described.
As shown in FIGS. 2A to 2C, a crystal resonator element 100b according to a third embodiment of the present invention includes a crystal piece 10b having convex portions 11c and 11d on both main surfaces, and the convex portion It is mainly composed of electrodes 12c and 12d provided on the main surface of the part.
In the crystal resonator element 100b according to the second embodiment, the lengths of the first convex portion 11c, the second convex portion 11d, the first electrode 12c, and the second electrode 12d in the X-axis direction are the same. They differ from the second embodiment in different points.

  Similarly to the second embodiment, the crystal piece 10b is an AT cut and is formed in an elliptical shape. Here, when the convex portion provided on one main surface is the first convex portion 11c and the convex portion provided on the other main surface is the second convex portion 11d, the first convex portion 11c is: It is formed smaller than the second convex portion 11d. That is, the surface area of the main surface of the first protrusion 11c is smaller than the surface area of the main surface of the second protrusion 11d. The first convex portion 11c and the second convex portion 11d are formed such that the planar shape of the main surface is an ellipse.

Electrodes are provided on the main surface of the first convex portion 11c and the main surface of the second convex portion 11d. The electrode provided on the main surface of the first convex portion 11c is referred to as a first electrode 12c, and the electrode provided on the main surface of the second convex portion 11d is referred to as a second electrode 12d.
The first electrode 12c is provided on the center side of the main surface of the first convex portion 11c. The second electrode 12d is provided on the center side of the main surface of the second convex portion 11d.
At this time, the first electrode 12c is provided smaller than the second electrode 12d. That is, the surface area of the first electrode 12c is provided smaller than the surface area of the second electrode 12d. The first electrode 12c and the second electrode 12d are formed in an elliptical shape in plan view.
Further, the surface area of the second electrode 12d is formed smaller than the surface area of the first convex portion 11c.

  Here, the relationship among the lengths of the first convex portion 11c, the second convex portion 11d, the first electrode 12c, and the second electrode 12d will be described (see FIG. 2). In the quartz resonator element 100b according to the third embodiment, as in the second embodiment, the X-axis direction of the AT-cut quartz piece 10b is the reference direction for the length. At this time, each length is the length of the ellipse-shaped major axis, that is, the major axis. Further, the Z-axis direction may be used as the reference direction for the length. In this case, for example, the Z-axis direction is the minor axis direction of the ellipse.

First, the length L4 of the crystal piece 10b in the X-axis direction is determined in advance. At this time, the end portions P5a and P5b having a length L4 in the X-axis direction of one main surface of the crystal piece 10b are in a state of being positioned on the contour of a virtual circle having a predetermined radius R3. In this state, both end portions P6a and P6b of the length L5 of the first convex portion 11c are positioned on the contour of the predetermined circle.
In other words, the length L4 of the crystal piece 10b is a length in which both end portions P5a and P5b of one main surface of the length L4 are positioned on the contour of a circle having a predetermined radius R3. The length L4 of the crystal piece 10b is determined in advance.
Further, the first convex portion 11c has a length in which both end portions P6a and P6b of the length L5 are positioned on the contour of the circle having the predetermined radius R3 from a position away from the crystal piece 10a in consideration of the thickness. To do.
In addition, the first electrode 12c is described later in a circular outline having the predetermined radius R3 from a position away from the crystal piece 10b in consideration of the thickness of the first convex portion 11c and the first electrode 12c. The center point P7 of the length L8, that is, the plane center is located.

Next, the length L6 in the X-axis direction of the second convex portion 11d provided on the other main surface of the crystal piece 10b is determined.
In this case, both end portions P8a and P8b of the length L6 of the second convex portion 11d are located on the contour of a circle having a predetermined radius R4. At this time, when the thickness of the second protrusion 11d is the same as that of the first protrusion 11c, the length L6 of the second protrusion 11d is longer than the length L5 of the first protrusion 11c. Thus, both end portions P8a and P8b having a length L6 are positioned on the contour of the predetermined circle.

Next, the length L7 of the second electrode 12d is determined in this state.
Both ends P9a and P9b of the length L7 of the second electrode 12d having a predetermined thickness are in a state of being positioned on the contour of the circle having the predetermined radius R4. At this time, the length L7 of the second electrode 12d is shorter than the length L5 of the first convex portion 11c.

  Note that the thickness of the second electrode 12d is a thickness converted to the density of quartz when positioned on the contour of the circle having the predetermined radius R4. Therefore, the actual thickness of the second electrode 12d is a value different from the thickness when positioned on the contour of the circle having the predetermined radius R4.

Next, the length L8 of the first electrode 12c is determined.
Both end portions of the length L8 of the first electrode 12c having the same thickness as the second electrode 12d are not located on the contour of the circle having the predetermined radius R3, and have an arbitrary length. At this time, the length L8 of the first electrode 12c is shorter than the length L6 of the second electrode 12d.

  According to such a crystal resonator element 100b according to the third embodiment of the present invention, the surface area of the first protrusion 11c is smaller than the surface area of the second protrusion 11d, and the surface area of the first electrode 12c is smaller. Since the surface area of the second electrode 12d is smaller than that of the second electrode 12d and the surface area of the second electrode 12d is smaller than the surface area of the first convex portion 12c, a pseudo-convex crystal piece is obtained. Unnecessary vibration is less likely to occur in the contour portion, the contour portion of the first convex portion 11c, the contour portion of the second convex portion 11d, the contour portion of the first electrode 12c, and the contour portion of the second electrode 12d, and is low. The CI value can be improved so as to be the CI value.

  Further, according to the crystal resonator element 100b according to the third embodiment of the present invention, the both ends P5a and P5b of the length L4 in the X-axis direction of the crystal piece 10b and the X of the first convex portion 11c are used. Both ends P6a and P6b having an axial length L5, both ends P8a and P8b having an X-axis length L6 of the second convex portion 11d, and a second electrode corresponding to the X-axis direction of the crystal piece 10b Since both end portions P9a and P9b having a length L7 of 12d are positioned on the contour of a predetermined circle, a shape that makes it difficult to generate unnecessary vibration can be obtained, and the CI value can be improved.

(Modification of the third embodiment)
Next, a modification of the crystal resonator element according to the modification of the third embodiment of the present invention will be described.
As shown in FIG. 3, the crystal resonator element 100b2 according to the modification of the third embodiment of the present invention is different from the first embodiment in that the first electrode is configured to be larger than the second electrode. Is different.
In addition, the electrode provided in the 1st convex part 11c is set as the 1st electrode 12c2, and the electrode provided in the 2nd convex part 11d is set as the 2nd electrode 12d2.

At this time, the first electrode 12c2 is provided larger than the second electrode 12d2. That is, the surface area of the first electrode 12c2 is larger than the surface area of the second electrode 12d2. The first electrode 12c2 and the second electrode 12d2 are formed in an elliptical shape in plan view.
The surface areas of the first electrode 12c2 and the second electrode 12d2 are formed to be smaller than the surface area of the first protrusion 11c.
In the present embodiment, the second electrode 12d2 is provided smaller than the first electrode 12c2. In this case, both end portions of the second convex portion 11d and the center point of the plane of the second electrode 12d2 are configured to be in contact with the predetermined radius R4. Further, both ends of the crystal piece 10b, both ends of the first convex portion 11c, and both ends of the first electrode 12c are configured to contact a circle having a predetermined radius R3.

  The crystal resonator element 100b2 according to the modification of the third embodiment of the present invention also has the same effect as that of the third embodiment.

(Fourth embodiment)
Next, a crystal resonator element according to a fourth embodiment of the invention will be described.
As shown in FIG. 4, a crystal resonator element 100c according to a fourth embodiment of the present invention is provided on a crystal piece 10c having convex portions 11e and 11f on both main surfaces, and on the main surface of the convex portions. The electrodes 12e and 12f are mainly configured.
In the crystal resonator element 100c according to the third embodiment, the lengths of the first convex portion 11e, the second convex portion 11f, the first electrode 12e, and the second electrode 12f in the X-axis direction are the same. Different from the second embodiment in each different point, the second electrode 12f differs from the third embodiment in that the surface area of the second electrode 12f is larger than the surface area of the first convex portion 11e.

  Similarly to the second embodiment, the crystal piece 10c is an AT cut and is formed in an elliptical shape. Here, when the convex portion provided on one main surface is the first convex portion 11e and the convex portion provided on the other main surface is the second convex portion 11f, the first convex portion 11e is: It is formed smaller than the second convex portion 11f. That is, the surface area of the main surface of the first protrusion 11e is formed smaller than the surface area of the main surface of the second protrusion 11f. The first convex portion 11e and the second convex portion 11f are formed such that the planar shape of the main surface is an ellipse.

Electrodes are provided on the main surface of the first convex portion 11e and the main surface of the second convex portion 11f. The electrode provided on the main surface of the first convex portion 11e is referred to as a first electrode 12e, and the electrode provided on the main surface of the second convex portion 11f is referred to as a second electrode 12f.
The first electrode 12e is provided on the center side of the main surface of the first convex portion 11e. The second electrode 12f is provided on the center side of the main surface of the second convex portion 11f.
At this time, the first electrode 12e is provided smaller than the second electrode 12f. That is, the surface area of the first electrode 12e is provided smaller than the surface area of the second electrode 12f.
Further, the first electrode 12e and the second electrode 12f are formed in an elliptical shape in plan view.

  Here, the relationship among the lengths of the first convex portion 11e, the second convex portion 11f, the first electrode 12e, and the second electrode 12f will be described (see FIG. 4). In the quartz resonator element 100c according to the fourth embodiment, the X-axis direction of the AT-cut quartz piece 10c is the reference direction of the length, as in the third embodiment. At this time, each length is the length of the ellipse-shaped major axis, that is, the major axis. Further, the Z-axis direction may be used as the reference direction for the length. In this case, for example, the Z-axis direction is the minor axis direction of the ellipse.

  First, the length L9 of the crystal piece 10c in the X-axis direction is determined in advance. At this time, the end portions P10a and P10b having the length L9 in the X-axis direction of one main surface of the crystal piece 10c are in a state of being located on the contour of a virtual circle having a predetermined radius R5. In this state, both end portions P11a and P11b of the length L10 of the first protrusion 11e are located on the contour of the circle having the predetermined radius R5.

In other words, the length L9 of the crystal piece 10c is a length in which both end portions P10a and P10b of one main surface of the length L9 are positioned on the contour of a circle having a predetermined radius R5. The length L9 of the crystal piece 10c is determined in advance.
Further, the first convex portion 11e has a length in which both end portions P11a and P11b of the length L10 are positioned on the contour of the circle having the predetermined radius R5 from a position away from the crystal piece 10c in consideration of the thickness. To do.

  In addition, the first electrode 12e is described later on the outline of the circle having the predetermined radius R5 from a position away from the crystal piece 10c in consideration of the thickness of the first protrusion 11e and the first electrode 12e. The center point P12 of the length L13, that is, the plane center is located.

Next, the length in the X-axis direction of the second convex portion 11f provided on the other main surface of the crystal piece 10c is determined.
In this case, both end portions P13a and P13b of the length L11 of the second convex portion 11f are located on the contour of a circle having a predetermined radius R6. At this time, when the thickness of the second protrusion 11f is the same as that of the first protrusion 11e, the length L11 of the second protrusion 11f is greater than the length L10 of the first protrusion 11e. Both ends P13a and P13b of length L11 are positioned on the contour of a circle having a predetermined radius R6 so as to be longer.
In this state, the length of the second electrode 12f is determined.
Both ends P14a and P14b of the length L12 of the second electrode 12f having a predetermined thickness are in a state of being located on the contour of the circle having the predetermined radius R6. At this time, the length L12 of the second electrode 12f is longer than the length L10 of the first convex portion 11e.

  Note that the thickness of the second electrode 12f is a thickness converted to the density of crystal when positioned on the contour of the circle having the predetermined radius R6. Therefore, the actual thickness of the second electrode 12f is a value different from the thickness when positioned on the contour of the circle having the predetermined radius R6.

Next, the length L13 of the first electrode 12e is determined.
Both ends of the length L13 of the first electrode 12e having the same thickness as that of the second electrode 12f are not located on the contour of the circle having the predetermined radius R5, and have an arbitrary length. At this time, the length L13 of the first electrode 12e is shorter than the length L12 of the second electrode 12f.

  According to the crystal resonator element 100c according to the fourth embodiment of the present invention, the surface area of the first protrusion 11e is smaller than the surface area of the second protrusion 11f, and the surface area of the first electrode 12e is smaller. Since the surface area of the second electrode 12f is smaller than that of the second electrode 12f and the surface area of the second electrode 12f is larger than that of the first convex portion 12e, a pseudo-convex crystal piece is obtained. Unnecessary vibrations are less likely to occur at the contour portion, the contour portion of the first convex portion 11e, the contour portion of the second convex portion 11f, the contour portion of the first electrode 12e, and the contour portion of the second electrode 12f, which are low. The CI value can be improved so as to be the CI value.

  Further, according to the crystal resonator element 100c according to the fourth embodiment of the present invention, the both ends P10a and P10b of the length L9 in the X-axis direction of the crystal piece 10c and the X of the first convex portion 11e are used. Both ends P11a, P11b of the length L10 in the axial direction, both ends P13a, P13b of the length L11 in the X-axis direction of the second protrusion 11f, and the second electrode corresponding to the X-axis direction of the crystal piece 10c Since both end portions P14a and P14b of the length L12 of 12f and the point P12 at the center of the plane of the first electrode 12e are located on the contour of a predetermined circle, it becomes a shape that makes it difficult to generate unnecessary vibration. , CI value can be improved.

(Modification)
Next, a modified example will be described.
For example, as shown in FIGS. 5A to 5B, a crystal resonator element 100d according to the modification includes a crystal piece 10d, a first convex portion 11g, a second convex portion 11h, a first electrode 12g, It is composed of the second electrode 12h. At this time, the relationship in length in the X-axis direction of the crystal piece 10d, the first protrusion 11g, the second protrusion 11h, the first electrode 12g, and the second electrode 12h is the same as in the third embodiment. And
As described above, in the crystal resonator element 100d according to the modification, the crystal piece 10d, the first convex portion 11g, the second convex portion 11h, the first electrode 12g, and the second electrode 12h have a quadrangular shape. The same effects as in the third embodiment are achieved.

Next, examples will be described.
In Example 1, the length of the crystal piece in the X-axis direction is 1000 μm, the length of the first convex portion is 580 μm, the length of the second convex portion is 820 μm, The length is 370 μm, the length of the second electrode is 410 μm, the radius of the predetermined circle is 10 mm, the end of the crystal piece in the X-axis direction, the length of the first convex portion , The end of the length of the second convex portion, and the end of the length of the second electrode are located on the contour of the circle having the radius of 10 mm.
The structure of Example 1 is the same as that of the crystal resonator element of the third embodiment.
Here, as shown in FIG. 6, when the shape of the crystal resonator element is Example 1, the vibration generated in the crystal resonator element is concentrated on the portion where the first electrode or the second electrode is formed. I can confirm that.
This is because unnecessary vibration is generated in the contour portion of the crystal piece, the contour portion of the first convex portion, the contour portion of the second convex portion, the contour portion of the first electrode, and the contour portion of the second electrode. It is not considered.

In Comparative Example 1, the length of the crystal piece in the X-axis direction is 1000 μm, the length of the first convex portion is 800 μm, the length of the second convex portion is 800 μm, The length is 600 μm, and the length of the second electrode is 600 μm.
That is, in the case of the comparative example 1, the length of the 1st convex part and the length of the 2nd convex part are the same, and the length of the 1st electrode and the length of the 2nd electrode are the same.
Further, the shape of the crystal piece, the shape of the first convex portion, the shape of the second convex portion, the shape of the first electrode, and the shape of the second electrode are formed in an ellipse shape.
Here, as shown in the figure, when the shape of the crystal resonator element is Comparative Example 1, it can be confirmed that the vibration generated in the crystal resonator element is irregularly generated with a number of vibration peaks. This is because of the vibration expected in the design, the contour part of the crystal piece, the contour part of the first convex part, the contour part of the second convex part, the contour part of the first electrode, the contour part of the second electrode It is thought that the unnecessary vibrations generated in the above are combined.

In Comparative Example 2, the length of the crystal piece in the X-axis direction is 1100 μm, the length of the first convex portion is 800 μm, the length of the second convex portion is 800 μm, The length is 600 μm, and the length of the second electrode is 600 μm.
That is, in the case of the comparative example 2, the length of the first convex portion and the length of the second convex portion are the same, and the length of the first electrode and the length of the second electrode are the same.
In addition, the shape of the crystal piece, the shape of the first protrusion, the shape of the second protrusion, the shape of the first electrode, and the shape of the second electrode are formed in a quadrangle.
Here, as shown in the figure, when the shape of the crystal resonator element is Comparative Example 2, as in Comparative Example 1, the vibration generated in the crystal resonator element generates vibrations that can irregularly form a number of peaks. You can see that This is because of the vibration expected in the design, the contour part of the crystal piece, the contour part of the first convex part, the contour part of the second convex part, the contour part of the first electrode, the contour part of the second electrode It is thought that the unnecessary vibrations generated in the above are combined.

  Thereby, compared with the comparative example 1, Example 1 does not leak the vibration which generate | occur | produces from the part of a 1st electrode and a 2nd electrode, and since unnecessary vibration does not generate | occur | produce, CI value is made low. I was able to.

As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment. For example, the crystal piece, the first convex portion, the second convex portion, the first electrode, and the second electrode may be polygonal.
In the case where the center point of the plane is in contact with a circle having a predetermined radius, it is preferable to use the smaller one of the first electrode and the second electrode.
For example, when the size of the first electrode is smaller than that of the second electrode, the radius of a predetermined circle is determined so as to be in contact with the center point of the first convex portion and the plane of the first electrode. For example, when the size of the second electrode is smaller than that of the first electrode, the radius of the predetermined circle is determined so as to be in contact with the center point of the second convex portion and the plane of the second electrode.
Thus, even if the present invention is configured, a pseudo convex structure can be configured.
Further, the first electrode and the second electrode can be provided on the crystal piece by using a vapor deposition technique or a plating technique. The first convex portion, the second convex portion, the first electrode, and the second electrode can be formed by a photolithography technique or an etching technique.

100a, 100b, 100c, 100d Quartz vibrating element 10a, 10b, 10c, 10d Quartz piece 11a, 11c, 11e, 11g First convex portion 11b, 11d, 11f, 11f Second convex portion 12a, 12c, 12e, 12g First electrode 12b, 12d, 12f, 12h Second electrode R1, R2, R3, R4, R5, R6 Radius

Claims (7)

There are convex portions on both main surfaces of the plate-shaped crystal piece, one convex portion is a first convex portion, and the other convex portion is a second convex portion, and the first convex portion is provided on the first convex portion. A quartz crystal vibration element comprising one electrode and a second electrode provided on the second convex portion,
The crystal resonator element, wherein the surface area of the first convex portion is provided smaller than the surface area of the second convex portion. There are convex portions on both main surfaces of the plate-shaped crystal piece, one convex portion is a first convex portion, and the other convex portion is a second convex portion, and the first convex portion is provided on the first convex portion. A quartz crystal vibration element comprising one electrode and a second electrode provided on the second convex portion,
The surface area of the first convex part is smaller than the surface area of the second convex part,
The surface area of the first electrode is smaller than the surface area of the second electrode;
The first electrode is provided on the entire main surface of the first protrusion,
The quartz resonator element, wherein the second electrode is formed on the entire main surface of the second convex portion. When the crystal resonator element uses the crystal piece whose plane is parallel to the X axis and the Z axis, and the reference direction of the length is the X axis direction or the Z axis direction,
Both ends of the length of the crystal piece in the X-axis direction or the Z-axis direction;
A planar center of the first electrode;
Both ends of the length of the second electrode in the X-axis direction or Z-axis direction provided on the entire main surface of the second convex portion;
The crystal resonator element according to claim 2, wherein the crystal resonator element is located on a contour of a predetermined circle. There are convex portions on both main surfaces of the plate-shaped crystal piece, one convex portion is a first convex portion, and the other convex portion is a second convex portion, and the first convex portion is provided on the first convex portion. A quartz crystal vibration element comprising one electrode and a second electrode provided on the second convex portion,
The surface area of the first convex part is smaller than the surface area of the second convex part,
The surface area of the first electrode is smaller than the surface area of the second electrode;
The quartz resonator element, wherein the surface area of the second electrode is formed larger than the surface area of the first convex portion. There are convex portions on both main surfaces of the plate-shaped crystal piece, one convex portion is a first convex portion, and the other convex portion is a second convex portion, and the first convex portion is provided on the first convex portion. A quartz crystal vibration element comprising one electrode and a second electrode provided on the second convex portion,
The surface area of the first convex part is smaller than the surface area of the second convex part,
The surface area of the first electrode and the surface area of the second electrode are different sizes,
The crystal resonator element, wherein the surface area of the first electrode and the surface area of the second electrode are formed to be smaller than the surface area of the first protrusion. When the crystal resonator element uses the crystal piece whose plane is parallel to the X axis and the Z axis, and the reference direction of the length is the X axis direction or the Z axis direction,
Both ends of the length of the crystal piece in the X-axis direction or the Z-axis direction;
Both ends of the length of the first convex portion in the X-axis direction or the Z-axis direction;
A planar center of the first electrode;
Both ends of the length of the second convex portion in the X-axis direction or the Z-axis direction;
Both ends of the length of the second electrode corresponding to the X-axis direction or the Z-axis direction of the crystal piece;
6 is located on the outline of a predetermined circle. 6. The crystal resonator element according to claim 4, wherein: The shape of the crystal piece;
The shape of the first convex portion;
The shape of the second convex portion;
The shape of the crystal piece;
The shape of the crystal piece;
The crystal resonator element according to claim 1, wherein the quartz resonator element has a predetermined ellipse shape.

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