JP2008109538A - Crystal oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a crystal oscillator particularly for surface mounting, having enhanced junction intensity to a mount substrate (vessel main body) of a crystal chip. <P>SOLUTION: The crystal oscillator, of which outer circumference portion having an extraction electrode 7 extended from each oscillation electrode 6 of both main planes is secured on a crystal terminal 4 of the mount substrate by a conductive adhesive agent 8, includes a concave and a convex in the plane direction on the outer circumference portion of a crystal chip 2 having the above extended extraction electrode 7. Inside the outer circumference of the crystal chip, the above conductive adhesive agent is coated in the plane of both the crystal terminal and the crystal chip having the extended extraction electrode, in a circular shape centering a central portion of the outer circumference of the crystal chip having the extended extraction electrode. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to, for example, a crystal resonator for surface mounting (hereinafter referred to as a surface mount resonator) in the technical field, and more particularly to an electrode structure of a crystal piece with increased holding strength corresponding to downsizing.

(Background of the Invention)
Since surface-mounted resonators are small and light, they are used as frequency and time reference sources, especially in portable electronic devices. In recent years, miniaturization has permeated, and accordingly, it has been required to reduce the size of the crystal piece itself. For example, in a 2025 size (outer dimension is 2 × 2.5 mm) with a frequency band of 26 MHz in the de facto standard (an established standard), the crystal piece is approximately 0.8 × 0.6 mm.

(Example of conventional technology)
FIG. 4 is a view of a surface mount moving element for explaining one conventional example. FIG. 4 (a) is a sectional view and FIG. 4 (b) is a plan view excluding the cover 3. FIG.

  The surface mounting moving element has a rectangular planar outer shape, a crystal piece 2 is accommodated in a container body 1 as a mounting substrate, and a cover 3 is covered and hermetically sealed. The container body 1 is made of a laminated ceramic having a concave shape, and has crystal terminals 4 on both sides of, for example, one end of the inner bottom surface. The container body 1 has an external terminal 5 on the outer bottom surface, and is electrically connected to the crystal terminal 4 through the laminated surface and the side surface. The crystal terminal 4 has a rectangular shape of 0.1 × 0.08 mm.

  The crystal piece 2 is rectangular, for example, as an AT cut, and has excitation electrodes 6 on both main surfaces. From the excitation electrode 6, the extraction electrode 7 is extended on both sides of one end portion which is an outer peripheral portion. The extraction electrode 7 includes a first extraction portion 7a extending from the excitation electrode 6 and a second extraction portion 7b as a holding portion on both sides of one end connected to the first extraction portion 7a. The 2nd drawer | drawing-out part 7b has the 3rd drawer | drawing-out part (folding part) 7c formed by folding up to the opposite surface of the crystal piece 2 through an end surface. The second and third lead portions 7 (bc) have the same shape. For example, the excitation electrode 6 and the extraction electrode 7 have Cr as a base electrode and Au as a main electrode.

  And the 2nd and 3rd drawer | drawing-out part 7 (bc) of the one end part in the one main surface of the crystal piece 1 made into the magnitude | size comparable as the crystal terminal 4 is fixed by the conductive adhesive 8. FIG. The conductive adhesive 8 is applied over the inner bottom surface of the container body 1 in the length direction, for example, from the second lead portion 7b. Thereby, the center of the conductive adhesive applied in a circular shape is from the inner wall of the container body. In other words, the inner wall is closer to the center of the second and third lead portions 7 (bc).

The cover 3 is made of metal, and the outer periphery is joined to the opening end surface by, for example, seam welding. The external terminal 5 to be connected as the crystal terminal 4 is connected to one set of diagonal parts, and the metal cover 3 is connected to the grounding external terminal 5 of another set of diagonal parts. Further, a metal ring (not shown) including a thick film for welding is provided on the opening end face of the container body 1.
Japanese Patent No. 3865683

(Problems of conventional technology)
However, in the surface-mounted resonator having the above-described configuration, the inner product of the container body 1 is reduced when the size is further reduced. For this reason, for example, the conductive adhesive 8 does not protrude outside the crystal piece 2 but only between the crystal terminal 4 and the inner bottom surface of the container main body 1 to reduce the size. In other words, it was considered to enlarge the crystal piece 1. However, in this case, there is a problem that the amount of the conductive adhesive 8 decreases and the bonding strength decreases.

(Object of invention)
An object of the present invention is to provide a crystal resonator in which the bonding strength of a crystal piece to a mounting substrate (container body) is increased.

  According to the present invention, as shown in the claims (Claim 1), the outer peripheral portion where the extraction electrode extends from the excitation electrode on both main surfaces is fixed to the crystal terminal of the mounting substrate by the conductive adhesive. In the crystal resonator according to the present invention, a planar unevenness is provided on the outer peripheral portion of the crystal piece from which the extraction electrode extends.

  With such a configuration, the surface area of the crystal piece from which the extraction electrode is extended is increased, so that the substantial surface area is increased. Therefore, the adhesive strength by the conductive adhesive can be increased.

(Embodiment section)
In claim 2 of the present invention, in claim 1, the conductive adhesive is applied to the outer periphery of the crystal piece. This effectively utilizes the bottom surface area of the mounting substrate to promote downsizing.

  In the third aspect of the present invention, in the first aspect, the conductive adhesive is applied in a circular shape around the center of the outer peripheral portion of the crystal piece from which the extraction electrode extends. Thereby, the protrusion of the conductive adhesive applied in a circular shape from the outer periphery of the crystal piece is reduced, and the configuration of claim 2 is realized.

  In the fourth aspect of the present invention, in the first aspect, the conductive adhesive is applied to an outer peripheral portion of the crystal piece from which the extraction electrode extends. This prevents an electrical short circuit in the width direction of the crystal piece and maintains good vibration characteristics with little influence on the central region (vibration region).

  In claim 5, the outer peripheral portion of the crystal piece from which the extraction electrode extends and the crystal terminal have the same shape and the same position in plan view, and the conductive adhesive is the outer periphery of the crystal piece. It is applied in the plane of the part and the crystal terminal. Thereby, the structure of Claims 1-5 becomes more concrete.

  In claim 6, in claim 1, the extraction electrode includes a first extraction portion extending from the excitation electrode, and a folded portion connected to the first extraction portion and provided on an outer peripheral portion of the crystal piece. And a second drawer portion. Thereby, the structure of the extraction electrode in Claim 1 is further clarified.

  FIG. 1 is a view of a surface-mounted moving element for explaining an embodiment of the present invention. FIG. 1 (a) is a sectional view and FIG. 1 (b) is a plan view excluding a cover. In addition, the same number is attached | subjected to the same part as a prior art example, and the description is simplified or abbreviate | omitted.

  As described above, the surface mount slider is electrically conductive to the crystal terminal 4 provided on the inner bottom surface of the container body 1 in which both ends of the crystal piece 2 from which the extraction electrode 7 extends from the excitation electrode 6 are concave. It is fixed by the adhesive 8. And the metal cover 3 is joined to the opening end surface of the container main body 1 by seam welding, for example.

  The extraction electrode 7 of the crystal piece 2 is again composed of a first extraction portion 7 a extending from the excitation electrode 6 and a second extraction portion 7 b having folded portions 7 c provided on both sides of one end portion. And as shown in FIG. 2, the one main surface of the one end part side where the 2nd drawer | drawing-out part 7b extended is provided with an unevenness | corrugation in a planar direction, for example, a two-dimensional direction (vertical and horizontal). 2A is a partially enlarged plan view, and FIG. 2B is a cross-sectional view taken along the line AA. The colored part in FIG. 2 (a) is the convex part 9a, and the non-colored part is the concave part 9b.

  These are first formed with concavo-convexities on one main surface on both sides of one end of the crystal piece 2 by etching using a photolithographic technique in a state of a crystal wafer (not shown), for example. Next, the excitation electrode 6 and the extraction electrode 7 are formed. In this case, the folded portion 7c of the second lead portion 7b is formed on the opposite surface by a through hole. Or after forming an unevenness | corrugation in a quartz wafer, it divides | segments and divides | segments into each crystal piece 2, and forms the excitation electrode 6 and the extraction electrode 7 by vapor deposition or sputtering.

  First, a thermosetting conductive adhesive 8 is applied on the crystal terminal 4 provided on the inner bottom surface of the container body 1. Here, the crystal terminal 4 has the same shape as the second lead portion 7b (folded portion 7c). The conductive adhesive 8 has a circular shape centered on the center portion of the crystal terminal 4, and is further applied to the surface of the crystal terminal 4.

  Next, the second lead portion and the folded portion 7 (bc) on both sides of the one end portion of the crystal piece 2 are positioned on each crystal terminal 4. In this case, the 2nd drawer part and the folding | returning part 7 (bc) are made into the same position on each crystal terminal 4 by planar view. As a result, the conductive adhesive 8 is applied in a circular shape around the center of the second drawn-out portion and the folded portion 7 (bc). Furthermore, the conductive adhesive 8 is applied to the surface of the second drawn portion and the folded portion 7 (bc) without protruding from the outer periphery of the crystal piece 2. Then, the conductive adhesive 8 is heated and melted, and the outer peripheral portions that are both sides of one end of the crystal piece 2 are fixed.

  With such a configuration, both sides of the one end portion, which is the outer peripheral portion of the crystal piece 2 from which the extraction electrode 7 extends, have vertical and horizontal irregularities, so that the substantial surface area increases. Therefore, the adhesive strength with respect to the crystal terminal 4 can be increased. Further, since the conductive adhesive 8 is in the plane on both sides of the one end portion of the crystal piece 2, it is possible to promote miniaturization by eliminating the protrusion of the conductive adhesive 8. And the electrical short by the conductive adhesives in the width direction of the crystal piece 2 is prevented. In addition, since the vibration region where the excitation electrode 6 is formed is also separated, the vibration characteristics are favorably maintained.

(Other matters)
In the above embodiment, the crystal piece 2 has a flat plate shape. However, for example, as shown in FIG. 3 (cross-sectional view), the crystal piece 2 is also applied to an inverted mesa structure including a vibrating portion having a small thickness and an outer peripheral portion having a larger thickness. it can. In this case, the leading end surface of the leg portion having a large thickness becomes the second lead portion 7b and becomes an uneven surface. In the case of the inverted mesa structure, since the thickness of the outer peripheral portion where the extraction electrode 7 extends is large, the depth of the unevenness can be increased. Therefore, the leg width of the outer peripheral portion can be narrowed to maintain the adhesive strength.

  Moreover, although the unevenness | corrugation of the convex part 9a and the recessed part 9b was arrange | positioned vertically and horizontally, for example, when a 2nd extraction electrode is circular shape etc., it is good also as radial, These can be arrange | positioned arbitrarily. Moreover, although the container main body 1 as a mounting substrate is concave, it may be a flat plate having mounting terminals. In this case, the concave cover is joined by, for example, glass sealing.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure of the surface mount moving element explaining one Embodiment of this invention, The figure (a) is sectional drawing, The figure (b) is a top view except a cover. 1A and 1B are diagrams of a crystal piece according to an embodiment of the present invention, in which FIG. 1A is a partial plan view, and FIG. It is sectional drawing of the crystal piece explaining the other example of application of this invention. It is a figure of the surface mount moving element explaining a prior art example, the figure (a) is a sectional view and the figure (b) is a top view except a cover.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Container body, 2 Crystal piece, 3 Cover, 4 Crystal terminal, 5 External terminal, 6 Excitation electrode, 7 Extraction electrode, 8 Conductive adhesive, 9a Convex part, 9b Concave part.

Claims (6)

  In the quartz crystal unit in which the outer peripheral portion of the lead electrode extending from the excitation electrode on both main surfaces is fixed to the crystal terminal of the mounting substrate by a conductive adhesive, the outer peripheral portion of the crystal piece from which the lead electrode is extended Quartz crystal having unevenness in a plane direction   2. The crystal resonator according to claim 1, wherein the conductive adhesive is applied in an outer periphery of the crystal piece.   2. The crystal resonator according to claim 1, wherein the conductive adhesive is applied in a circular shape around a center portion of an outer peripheral portion of the crystal piece from which the extraction electrode extends.   2. The crystal resonator according to claim 1, wherein the conductive adhesive is applied in an outer peripheral portion of a crystal piece from which the extraction electrode extends.   2. The crystal resonator according to claim 1, wherein the conductive adhesive is applied in a plane between the crystal terminal and an outer peripheral portion of the crystal piece from which the extraction electrode extends.   In Claim 1, the said extraction electrode has the 1st extraction part extended from the said excitation electrode, and the 2nd extraction part which has the return part provided in the outer peripheral part of the said crystal piece connected to the said 1st extraction part, A crystal unit consisting of