JP4498195B2 - Airtight terminal, piezoelectric vibrating piece, piezoelectric vibrator, oscillator, and electronic device - Google Patents

Description

  The present invention relates to an airtight terminal, a piezoelectric vibrating piece, a piezoelectric vibrator, an oscillator, and an electronic device.

  A crystal resonator is an electronic element indispensable for manufacturing industrial products, and is widely used as a clock function or a frequency control mechanism in electronic devices such as information communication devices and portable devices, household electric appliances, and the like.

  As a piezoelectric vibrator package, a box-shaped ceramic package or a cylinder-type package having leads is commonly used. Hereinafter, the configuration of the cylinder type package will be briefly described with reference to the drawings.

  FIG. 10 is an example of a conventional cylinder type package of a new crystal unit. Here, an example of a tuning fork type crystal resonator is shown. FIG. 10A is a schematic diagram of a tuning-fork type crystal vibrating piece. The piezoelectric vibrating piece 6 made of quartz has a base portion 7 and a pair of vibrating arms 6a formed so as to protrude from the base portion. A pattern of the excitation electrode 8 is formed on the surface of the vibrating arm 6a. A weight 6b is formed at the tip of the vibrating arm and is used for adjusting the frequency. A region pattern (hereinafter referred to as a mount pad, denoted by reference numeral 9) for electrical and mechanical connection with the outside is disposed on the base portion 7. The mount pad 9 is formed symmetrically with respect to the longitudinal center line of the piezoelectric vibrating piece.

  FIG. 10B is a diagram schematically showing the AA cross section of FIG. A first metal film (underlying metal film) 21 that forms a strong bonding layer with the crystal is formed on the surface of the crystal 20, and a second metal film 22 is formed thereon. Chromium (Cr) is commonly used for the first metal film 21 and gold (Au) is commonly used for the second metal film 22. A weight metal film 23 is formed on the weight portion.

  10 (c) and 10 (d) show examples of conventional airtight terminals. The hermetic terminal 1 has a metal outer ring called a stem 3 filled with a filler 4 for hermetic sealing, and the filler 4 has two leads 2 made of metal rods of the same diameter. The shape is symmetrical with respect to the center line and is fixed in a parallel manner. A plating layer 5 having a thickness of about 10 μm to 15 μm is formed on the surface of the lead 2 and the stem 3. An example of such an airtight terminal is disclosed (for example, see Patent Document 1).

  FIG. 10E shows the connection (referred to as a mount) between the piezoelectric vibrating piece 6 and the airtight terminal 1. The connection between the pair of leads 2 and the pair of mount pads 9 on the piezoelectric vibrating piece 6 is accomplished by melting a plating layer 5 (not shown) coated on the surface of the inner lead 2 a with energy from the outside and joining the mount pads 9. ing. As the material of the plating layer 5, tin (Sn), tin-lead alloy (Sn—Pb), tin-copper alloy (Sn—Cu), tin bismuth alloy (Sn—Bi), or the like is commonly used. Alternatively, a conductive adhesive can be used in addition to the bonding by melting the plating layer. In this case, silver (Ag) is desirable as the outermost surface layer of plating. The bottomed cylindrical case 10 is inserted along the outer shape of the stem 3 so as to cover the piezoelectric vibrating piece 6. In FIG.10 (e), the case 10 was shown with the thick dashed-dotted line, and it was set as the transparent body. The airtight joining between the stem 3 and the case 10 is realized by cold pressure welding via the plating layer 5 which is a soft metal of the outer ring of the stem 3.

  In the lead 2, the side joined to the piezoelectric vibrating reed 6 with the filler 4 as a boundary is referred to as an inner lead, denoted by reference numeral 2 a, and the lead mounted on the substrate or the like is referred to as an outer lead, and reference numeral 2 b Expressed in

  In recent years, as electronic devices represented by portable devices have been rapidly reduced in size and weight, the dimensions of electronic components have been further reduced. The dimension D shown in FIG. 10 (e) is changed from 2 mm to 1.5 mm, and a 1.2 mm piezoelectric vibrator is frequently used in mobile phones. In the future, when the mounting density is further increased, or the vibrator mounted on a thin card, an airtight terminal having a dimension D of 1 mm or less is required.

However, the current hermetic terminal structure in which a pair of leads having the same diameter is arranged symmetrically with respect to the center line of the stem has a limit in miniaturization. Even if the lead is downsized, the lead itself needs to have a certain level of rigidity against external forces such as bending. If the rigidity of the lead is insufficient, the positional accuracy with the piezoelectric vibrating piece is deteriorated and the strength of the bonding is likely to occur, and the yield of the assembly process is reduced. On the other hand, if leads with a large wire diameter are used to increase the rigidity, the distance between the leads will be reduced, and in the barrel plating process of the hermetic terminal manufacturing process, defects such as lead-to-plating will frequently occur and the manufacturing yield will increase. It was greatly reduced.
JP 2004-63387 A

  In view of the above problems, an object of the present invention is to propose a structure of a small hermetic terminal capable of suppressing a decrease in yield in the manufacturing process of the hermetic terminal and the assembly process of the piezoelectric vibrator.

  Conventionally, a pair of leads has been electrically insulated from the stem and case by a filler. That is, the stem and the case are used in an electrically floating state. However, the present invention has been made in consideration of the fact that the influence on the electric circuit is negligibly small even if the stem or the case is connected to one of the electrodes. Make the following suggestions:

  According to a first aspect of the present invention, there is provided an annular stem, a first lead disposed so as to penetrate through the stem and electrically insulated from the stem, and disposed within the stem, wherein the stem is electrically connected to the stem. An airtight terminal having a conductive second lead and a filler that hermetically seals the first lead and the second lead in the stem was obtained.

  According to a second aspect of the present invention, in the first aspect of the present invention, the airtight terminal has a cross-sectional area of the first lead larger than that of the second lead.

  According to a third aspect of the present invention, there is provided an annular stem having a projecting portion whose outer periphery extends in the axial direction, and is disposed so as to penetrate through the stem, and is electrically insulated from the stem. And an airtight terminal having a filler that hermetically seals the lead in the stem.

  Furthermore, in a fourth aspect based on the third aspect, the projecting portion is an airtight terminal extending both in the front and rear directions in the axial direction.

  In addition, the following proposal is made regarding the piezoelectric vibrating piece.

  According to a fifth aspect of the present invention, there is provided a piezoelectric vibrating piece made of a piezoelectric material, wherein the piezoelectric vibrating piece is formed on a surface of the piezoelectric vibrating piece, and is connected to the exciting electrode. And a connection region for performing electrical conduction to the outside, and the shape of the connection region is asymmetrical with respect to the longitudinal center line of the piezoelectric vibration member.

  In addition, the following proposal is made regarding the piezoelectric vibrator using the above-described hermetic terminal.

  A sixth invention is the airtight terminal of the first invention or the second invention, the piezoelectric vibrating piece joined to the first lead and the second lead of the airtight terminal, and the piezoelectric vibrating piece And a bottomed cylindrical case in which an airtight space is formed by inserting the stem of the airtight terminal so as to cover the piezoelectric vibrator.

  Furthermore, the following proposal is made with respect to a piezoelectric vibrator using an airtight terminal having an annular stem provided with a protruding portion whose outer periphery extends in the axial direction.

  In a seventh aspect of the present invention, the airtight terminal according to the third aspect or the fourth aspect of the invention, the piezoelectric vibrating piece joined to the lead and the protrusion of the airtight terminal, and the piezoelectric vibrating piece so as to cover the piezoelectric vibrating piece A piezoelectric vibrator having a bottomed cylindrical case in which the stem of the airtight terminal is inserted to form an airtight space.

  In addition, the following proposal is made using the above-described hermetic terminal and the newly proposed piezoelectric vibrating piece.

  The eighth invention is the piezoelectric vibrator of the sixth invention or the seventh invention, wherein the piezoelectric vibrating piece is the piezoelectric vibrating piece of the fifth invention.

  Further, the following proposal is made by applying the piezoelectric vibrator of the present invention to an oscillator and an electronic device.

  According to a ninth aspect of the invention, there is provided an oscillator that uses the piezoelectric vibrator according to any of the sixth to eighth aspects described above as an oscillator connected to an integrated circuit.

  Furthermore, a tenth aspect of the invention is an electronic device that uses the piezoelectric vibrator according to any of the sixth to eighth aspects of the invention connected to a timekeeping unit.

  Of the two pairs of leads constituting the hermetic terminal, one lead (second lead) is an airtight terminal having electrical continuity with the inner surface of the stem, thereby maximizing the distance between the pair of leads. As a result, the lead having a larger wire diameter than the conventional one can be adopted, and the rigidity of the lead can be increased. As a result, it is possible to solve the problem that the lead is bent in the assembly process, the positional accuracy of the piezoelectric vibrating piece is lowered, and the assembly yield is deteriorated. In addition, in the barrel plating process of the hermetic terminal manufacturing process, it is possible to suppress defects such as the connection between leads by plating. In addition, by using a lead having the same wire diameter as the conventional one, the stem outer diameter of the hermetic terminal can be made smaller than that of the conventional one, and a smaller hermetic terminal can be provided.

  Further, in the airtight terminal, the diameter of the lead (first lead) electrically insulated from the stem near the center line of the stem is increased to be larger than the cross-sectional area of the lead (second lead) connected to the stem. As a result, the lead having a large cross-sectional area and high rigidity and mechanically firmly fixing the piezoelectric vibrating piece and connected to the stem can be mainly intended for electrical connection. As described above, since a lead having a larger cross-sectional area and higher rigidity than the conventional one can be used, it is possible to provide an airtight terminal that does not reduce the assembly yield even when it is miniaturized.

  On the other hand, a projecting portion extending in the axial direction from a part of the outer periphery of the stem is arranged on one or both sides of the annular stem, and the projecting portion has a lead function. It is now possible to have only one lead. As a result, it is possible to increase the wire diameter of the lead that is fixed through, to improve the rigidity of the lead, and to further suppress the bending and twisting of the lead.

  In addition, by using the above-described hermetic terminal, it is possible to manufacture a piezoelectric vibrator that is further downsized than the conventional one with a high yield.

  Still further, the mounting pad formed on the base portion of the piezoelectric vibrating piece and joined to the lead has an asymmetric configuration, so that the alignment accuracy in joining with the above-described airtight terminal is improved.

  Furthermore, a piezoelectric vibrator using such a piezoelectric vibrating piece and the above-described hermetic terminal can be manufactured with a high yield in the assembly process even if it is downsized.

  Further, since the above-described piezoelectric vibrator is used as an oscillator connected to an integrated circuit, the oscillator requiring the maximum volume is reduced in size, and the oscillator can be further reduced as a whole.

  Furthermore, since the above-described piezoelectric vibrator is used as an electronic device connected to the time measuring unit, the volume of the time measuring unit is reduced, and an electronic device that can be further miniaturized can be configured.

  The best mode for carrying out the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected about the same component as the component demonstrated in background art, and the detailed description is abbreviate | omitted.

  As a first embodiment of the present invention, the first lead of the airtight terminal having two leads is electrically insulated from the inner surface of the stem, and the second lead is disposed on the inner surface of the stem. An airtight terminal which is fixed to and has electrical continuity will be described with reference to FIG. In the first to third embodiments, the lead is represented by a solid round bar, but the cross section of the lead may be a quadrangular shape regardless of this.

  FIG. 1 is a schematic configuration diagram showing an example of an airtight terminal according to the first embodiment of the present invention. FIGS. 1A and 1B are examples of hermetic terminals in which the lengths of two leads are substantially equal to each other, and FIG. 1B is a sectional view taken along line xx ′ of FIG. . FIG. 1C and FIG. 1D are examples of hermetic terminals in which the lengths of two leads are different from each other, and FIG. 1D is a sectional view taken along line xx ′ of FIG. The broken lines xx ′ and yy ′ shown in FIGS. 1A and 1C indicate the center line of the hermetic terminal.

  As shown in FIGS. 1A and 1B, of the two leads 11a and 11b made of a conductive material, the first lead 11a is near the center of the annular stem 3 also made of a conductive material. Are arranged so as to penetrate the stem 3. The first lead 11a is surrounded by a filler 4 for hermetic sealing, and is insulated and fixed from the inner surface of the stem 3. In this embodiment, low carbon steel (Fe) is used as the conductive material for the leads 11a and 11b and the stem 3, but iron nickel alloy (Fe—Ni), iron nickel cobalt alloy (Fe—Ni—Co), etc. May be used. Further, as the filler 4, soda lime glass is used, but soda barium glass or borosilicate glass may be used.

  The second lead 11b is made of the same material and the same size as the first lead 11a, and a part of the outer periphery thereof is mechanically fixed to the inner surface of the stem 3 by means of welding or the like. It arrange | positions so that it may have general conduction. A portion of the stem 3 that is not in contact with the inner surface of the stem 3 of the second lead 11b is surrounded and sealed by the filler 4 like the first lead 11a. That is, the second lead 11b is hermetically sealed and fixed between the inner surface of the stem 3 and the filler 4 without a gap, and is destroyed even in a test in which a constant tension is applied to the lead from the outside. It is possible to satisfy the airtight characteristics without any problems. When the second lead 11b is disposed in the stem 3, it is preferable to increase the distance from the first lead 11a as much as possible.

  Further, the length of the second lead 11b on the inner lead side is arranged to have the same length as the length of the first lead 11a on the inner lead side. The length of the second lead 11b on the outer lead side is designed to be substantially the same as the length of the first lead on the outer lead side.

  Next, an example of an airtight terminal in which the lengths of two leads, which are modifications of the first embodiment, are different from each other will be described with reference to FIGS. 1 (c) and 1 (d).

  The airtight terminal shown in FIGS. 1C and 1D has electrical continuity on the inner surface of the stem 3 with respect to the airtight terminal shown in FIGS. 1A and 1B. The lengths of the mechanically fixed second leads 12b are different. The second lead 12b is obtained by shortening the length of the outer lead below the stem 3 in FIG. 1D, and is arranged with an appropriate length shorter than the first lead 12a. A thick one-dot chain line AA in FIG. 1D indicates the bottom surface of the stem 3, and the lead length of the second lead 12 b is desirably at least the length to the bottom surface of the stem 3.

  Although not shown, tin (Sn), tin-lead alloy (Sn-Pb), tin-copper alloy is provided on the outer periphery of the stem 3 and the surfaces of the first and second leads in the airtight terminals of the above two examples. A plating layer selected from (Sn—Cu), tin-bismuth alloy (Sn—Bi), or the like is formed.

  In the hermetic terminal shown in the first embodiment, the two parallel leads are separated from each other in comparison with the conventional hermetic terminal having the two leads electrically insulated from the inner surface of the stem. Can be arranged wider than the conventional lead interval. As a result, it is possible to suppress a decrease in yield in the hermetic terminal manufacturing process due to the connection between the leads that is likely to occur in the barrel plating process of the hermetic terminal manufacturing process. In addition, since the lead wire diameter can be reviewed and a thicker wire diameter than before can be adopted, the rigidity of the lead is improved. As a result, bending of the leads and entanglement between the leads can be suppressed, and handling of the hermetic terminal in the vibrator assembly process is improved. Further, since the rigidity of the lead is improved, the position of the lead and the piezoelectric vibrating piece is determined more precisely, and the position accuracy of the mount is improved.

  As a second embodiment of the present invention, an airtight terminal in which the diameter of the first lead close to the center line of the stem is increased and the cross-sectional area of the second lead connected to the stem is made larger will be described with reference to FIG. To do.

  FIG. 2 is a schematic configuration diagram showing an example of an airtight terminal according to the second embodiment of the present invention. 2A and 2B are examples of hermetic terminals in which the lengths of two leads are substantially equal to each other, and FIG. 2B is a sectional view taken along line xx ′ of FIG. . 2C and 2D are examples of hermetic terminals in which the lengths of the two leads are different from each other, and FIG. 2D is a cross-sectional view taken along line xx ′ of FIG. 2 (a) and 2 (c), the broken lines xx ′ and yy ′ indicate the center line in each direction of the hermetic terminal, and the intersection of the center lines indicates the axial center of the hermetic terminal.

  As shown in FIGS. 2A to 2D, the airtight terminal of the second embodiment is different from the airtight terminal of the first embodiment in that the cross-sectional area of the first leads 13a and 14a and the second area are the same. The cross-sectional areas of the leads 13b and 14b are different from each other. Since other components are the same as the airtight terminal of the first embodiment, detailed description thereof is omitted.

  In the airtight terminal in which the lengths of the two leads shown in FIGS. 2 (a) and 2 (b) are substantially equal to each other, the first lead 13a having a large cross-sectional area and a large wire diameter has the axial center of the airtight terminal, That is, the stem 3 is arranged near the center at a position slightly decentered with respect to the axial center position. Further, the first lead 13 a is electrically insulated from the inner surface of the stem 3 via the filler 4 and is fixedly sealed. Even if the wire diameter and cross-sectional area of the first lead 13a are compared with those of the second lead 13b, the first leads 11a and 12a and the second leads 11b and 12b of the hermetic terminal of the first embodiment are used. It is thick and big compared to

  On the other hand, the thin second wire lead 13b having a small cross-sectional area is disposed at a position that is greatly decentered with respect to the axial center position of the stem 3. Further, the second lead 13 b is disposed so that a part of the outer periphery thereof is mechanically fixed to the inner surface of the stem 3 and has electrical continuity with the stem 3. The wire diameter of the second lead 13b is substantially the same as the thickness of the stem 3 in the radial direction.

  Next, an example of an airtight terminal in which the lengths of two leads, which are modifications of the second embodiment, are different from each other will be described with reference to FIGS. 2 (c) and 2 (d).

  The airtight terminals shown in FIGS. 2C and 2D have electrical continuity on the inner surface of the stem 3 with respect to the airtight terminals shown in FIGS. 2A and 2B. The lengths of the mechanically fixed second leads 14b are different. The second lead 14b is not provided with an outer lead as the length to the bottom surface of the stem 3 in FIG.

  In FIG. 2B and FIG. 2D, the connection with the piezoelectric vibrating piece is firmly fixed by the first lead 13a or 14a that is close to the center line and has a large cross-sectional area, as will be described later. The other second lead 13b or 14b having a small cross-sectional area has an auxiliary role in mechanically connecting and fixing the piezoelectric vibrating reed, and is mainly intended for electrical conduction. The first lead having a large cross-sectional area close to the center improves the rigidity of the lead as compared to the conventional lead in which two leads having the same wire diameter are arranged symmetrically with respect to the center of the stem. The position of the resonator element is precisely determined, improving the position accuracy of the mount. On the other hand, the second lead 13b or 14b, which is far from the center line, has a low rigidity because of its thin wire diameter. Accordingly, it is preferable that the length of the outer lead is shorter as shown by 14b in FIG. Note that the first leads 13a and 14a shown in FIG. 2 are eccentric from the center of the stem, but may be arranged at the center.

  The fact that the material dimensions used for the leads in manufacturing hermetic terminals are not uniform is one factor that reduces the mass production effect of the hermetic terminals themselves, but leads with different wire diameters and cross-sectional areas are provided. As a result, the following effects can be obtained. That is, the entire hermetic terminal can be miniaturized while maintaining strength, and the piezoelectric vibrator and electronic component using the miniaturized hermetic terminal are miniaturized while maintaining reliability, and an electronic device or apparatus in which these electronic components are incorporated Can be further downsized.

  As a third embodiment of the present invention, an airtight terminal having a protruding portion extending in the axial direction from a part of the outer periphery of the stem on one side or both sides of an annular stem will be described with reference to FIG.

  FIG. 3 is a perspective view showing a schematic configuration of an example of an airtight terminal according to a third embodiment of the present invention, and FIG. 3A shows an example in which a protruding portion is formed only in one front direction. FIG. 3B shows an example in which the protruding portions are formed on both the front and rear sides. In the present specification, the inner lead side of the lead in the airtight terminal is defined as the front of the stem, and the outer lead side is defined as the rear of the stem.

  The hermetic terminal shown in FIG. 3A has a narrow width extending from a part of the outer periphery of the stem 3 in the forward direction corresponding to the inner lead (upward direction in which the amount of protrusion of the lead 2 from the stem 3 is small). After the protrusion 3a is formed, the protrusion 3a is bent at an appropriate angle in the center direction of the stem. One lead 2 is provided, and the projecting portion 3a is paired with the lead 2 and serves as an inner lead.

  On the other hand, in the airtight terminal shown in FIG. 3B, a part of the outer periphery of the stem 3 is extended in both directions on the inner lead side in the axial direction and the rear outer lead side in the axial direction of the stem 3 so that the protruding portions 3a and 3b are formed. It is formed. The protruding portion 3a toward the inner lead is bent at an appropriate angle toward the center of the stem 3 as described above, and serves as an inner lead. The protrusion 3b formed on the outer lead side is arranged and formed with an appropriate length in parallel with the outer lead of the lead 2 that passes through the filler 4 and is fixed. The protruding portion 3b to the outer lead side is arranged with the intention of connecting to a lead frame when mounting a substrate or resin molding.

  In this embodiment, since the projecting portion serving as a lead is formed on the stem 3, it is possible to solve the narrowing of the distance between the leads, which is a problem when the hermetic terminal is downsized. Since the diameter of the lead 2 fixed through the filler can be increased, the rigidity of the lead is increased, the positions of the lead and the piezoelectric vibrating piece are accurately determined, and the positional accuracy of the mount is improved.

  As a fourth embodiment of the present invention, a piezoelectric vibrating piece in which the shapes of two connection regions are asymmetric with respect to the longitudinal center line of the piezoelectric vibrating piece will be described with reference to FIG.

  FIG. 4 shows an example in which a mount pad, which is a pair of connection regions formed at the base of a tuning fork type crystal piezoelectric vibrating piece, is asymmetric with respect to the longitudinal center line of the piezoelectric vibrating piece. In FIG. 4, the left mounting pad is wide. By increasing the area of the mount pad 9a, it is possible to position the mount pad 9a within the area of the mount pad even if a thick lead connected to the mount pad is selected. In addition, a margin can be provided for mechanical displacement between the mount pad and the lead. In addition, the plating coated on the lead sufficiently spreads to the mount pad in joining with the lead, thereby enabling strong joining. That is, the mechanical connection between the mount pad and the lead of the hermetic terminal is intended so that sufficient strength can be obtained only by the connection with one lead having a large diameter. On the other hand, the right mount pad 9b is narrow and therefore has a small area. The mount pad corresponds to connection with a protrusion that extends from the outer periphery of the stem when the lead is thin, and is intended for electrical connection.

  As a fifth embodiment of the present invention, a piezoelectric vibrator using the above-described hermetic terminal and a piezoelectric vibrating piece will be described with reference to FIGS.

  FIG. 5 shows an example of a piezoelectric vibrator using four types of hermetic terminals. 5 (a) and 5 (b) show a piezoelectric vibrator using an airtight terminal which is fixed to the inner surface of the stem and has electrical connection with the stem among the pair of leads having the same wire diameter. Is shown. FIG. 5A shows an AA cross section of FIG. In FIG. 5A, a circle indicated by reference numeral 10 is a case. A rectangle indicated by reference numeral 7 indicates a base portion of the piezoelectric vibrating piece. An inner pair of rectangles indicated by reference numeral 6 a indicates a vibrating arm, and the vibrating arm 6 a has a spatial margin with respect to the inner surface of the case 10.

  5 (c), 5 (d), 5 (e), and 5 (f), the diameter of the first lead near the center of the stem is large, and the second lead fixed on the inner surface of the stem is shown. It is an example of the piezoelectric vibrator using the airtight terminal larger than a cross-sectional area. In FIGS. 5E and 5F, the second lead 17b fixed to the inner surface of the stem does not extend to the outer lead side. The pair of mount pads 9a and 9b formed at the base of the piezoelectric vibrating piece are formed asymmetrically with respect to the longitudinal center line of the piezoelectric vibrating piece, and the width of the left mounting pad 9a is the right mounting pad. It is wider than the width of 9b. Since the left mounting pad 9a having a large area is connected to the first leads 16a and 17a having a large wire diameter and high rigidity, it is possible to achieve a strong connection with excellent positional accuracy. One mount pad 9b having a relatively small area is connected to second leads 16b and 17b which are fixed to the inner surface of the stem and have electrical continuity.

  FIG. 5G and FIG. 5H are examples of a piezoelectric vibrator using an airtight terminal having a stem extending from the outer periphery of the stem and provided with a protruding portion 3a on the inner lead side. The lead 18, the large mount, and the pad 9 a are connected to form a strong bond, and the protruding portion 3 a extending from the outer periphery of the stem is connected to the mount pad 9 b of the piezoelectric vibrating piece and serves as an inner lead.

  The mount pad and the lead are connected by bonding a plating film (not shown) coated on the lead surface to the mount pad surface by heating and melting with external energy such as heat. In addition, a conductive adhesive can be used for bonding without using a plating film.

  The hermetic sealing is realized by press-fitting a bottomed cylindrical metal case along the outer periphery of the stem in a vacuum or an inert gas atmosphere such as nitrogen so as to cover the piezoelectric vibrating piece. The inner diameter of this case is designed to be an interference fit with respect to the outer periphery of the stem. In the case of a tuning fork type crystal resonator as in this embodiment, sealing in a vacuum is suitable for the purpose of reducing the resonance resistance value.

  FIG. 6 shows an example of connection between the piezoelectric vibrator and the external circuit when the number of outer leads shown in FIGS. 5 (f) and 5 (h) is one. The outer lead 2b connected to the excitation electrode is bent into, for example, a crank shape and connected to the pattern 26a of the mounting board 25 using mounting solder 27. The other excitation electrode can be connected to the corresponding pattern 26 b of the mounting substrate 25 through the case 10 having electrical continuity with the stem 3. The case 10 and the pattern can be connected by mounting solder 27 or a combination of conductive adhesive and fixing adhesive (not shown).

  FIG. 7 shows an outline of a manufacturing flowchart of the piezoelectric vibrator. Briefly described below.

[Piezoelectric vibrating piece manufacturing process]
In the manufacturing process of the piezoelectric vibrating piece, first, after setting the quartz lamberde ore into a work table with the aid of the X-ray diffraction method so as to have a predetermined cutting angle, for example, by using a cutting device such as a wire saw, Is sliced and cut to a thickness of approximately 200 μm. Next, the wafer is polished until a certain thickness is reached. Thereafter, the surface is etched to remove the work-affected layer, and then polishing and cleaning are performed to finish a mirror surface having a predetermined thickness and a predetermined flatness (step 5).

  Subsequently, a metal thin film for a mask is deposited to a predetermined film thickness using a film forming means such as sputtering. The thin film is deposited on both sides of the wafer. Next, a mask for outer shape of the tuning fork vibrator is formed by lithography. Using this metal thin film mask, the crystal is etched with a hydrofluoric acid aqueous solution to form a plurality of external shapes on the wafer (step 10).

  Thereafter, all the metal film used as the mask is once peeled off. After the peeling, a metal thin film that becomes an electrode film with a predetermined film thickness is again deposited on the both surfaces of the wafer with a predetermined film thickness by a film forming means such as sputtering. After depositing the film, a pattern of the electrode film is formed using a lithography technique (step 15).

  Next, a weight metal film is formed in a thickness of several microns on the tip region of the vibrating arm (step 20). Subsequently, frequency adjustment (coarse adjustment) is performed. In coarse adjustment, a weight or the like is irradiated in the atmosphere with a laser to measure the oscillation frequency, and a part of the deposited weight metal film is evaporated to adjust the frequency to a predetermined range (step 25). Through the above-described steps, a wafer having a plurality of piezoelectric vibrating pieces is completed.

[Piezoelectric vibrator assembly process]
A plurality of hermetic terminals 1 of the present invention are aligned on a pallet, which is a jig for flow in an assembly process (step 30). Subsequently, a mounting process is performed (step 35). The piezoelectric vibrating piece manufactured according to the above and the inner lead of the airtight terminal are joined. In the mounting process, first, the piezoelectric vibrating reed 6 is cut out by a laser or mechanical means from a connecting portion (not shown) connecting the individual piezoelectric vibrating reeds and the wafer, and then aligned with the inner lead 2a. Next, the plating layer (not shown) of the inner lead 2 a is melted by applying heat from the outside, and joined to the mount pad 9 formed on the piezoelectric vibrating piece 6. As a means for melting the plating layer, heating by a laser or a light source or arc discharge heat can be used. Alternatively, the piezoelectric vibrating reed 6 can be connected with a conductive adhesive or the like without using the plating layer of the inner lead 2a.

  After the mounting process, baking is performed by heating to a predetermined temperature in a vacuum apparatus to remove distortion generated in the mounting process (step 40).

  Next is a frequency adjustment process (fine adjustment). Each pallet is fed into the vacuum device, and the outer lead 2b is probed to measure the oscillation frequency, while the laser beam is irradiated to the weight 6b of the vibrating arm of the piezoelectric vibrating piece, the adjustment metal film is evaporated and the frequency is adjusted. (Step 45). Thereafter, a plurality of pallets each having a frequency-adjusted piezoelectric vibrator are arranged in the mold, and the sealing case 10 is arranged to face each other. In order to desorb moisture and gas components adsorbed in the process before sealing, sufficient vacuum heating is performed in the sealing device. After the heating, the case 10 is press-fitted and vacuum-tight sealing can be performed (step 50). Airtightness is maintained by the case 10 designed to be an interference fit with the plating layer which is a soft metal of the outer ring of the stem. Thereafter, screening is performed at a predetermined temperature for the purpose of stabilizing the oscillation frequency (step 55).

  After the screening, the piezoelectric vibrator is inspected for an oscillation frequency, a resonance resistance value, and other electric characteristics in an electric characteristic inspection apparatus. In the electrical characteristic inspection, the outer lead 2b of the piezoelectric vibrator is probed and each characteristic is measured (step 60).

  After the measurement is finished, the aligned piezoelectric vibrators are removed from the pallet using a jig (step 65). The tuning fork type crystal resonator is completed through the above steps.

  In the frequency adjustment process and the electrical characteristic inspection process, conventionally, a pair of outer leads can be probed to measure electrical characteristics. However, in the present invention, one outer lead is used for miniaturization. In that case, the electrical characteristics can be measured by probing the outer lead and the stem or the case.

  As a sixth embodiment of the present invention, an oscillator in which the piezoelectric vibrator is connected to an oscillation circuit as an oscillator will be described with reference to FIG.

  FIG. 8 is a schematic diagram showing the configuration of a tuning fork type crystal oscillator according to the present invention, and shows a plan view of a surface mount type piezoelectric oscillator using the tuning fork type crystal resonator described above.

  In FIG. 8, a tuning fork type crystal resonator 51 is set at a predetermined position on a substrate 52, and an integrated circuit for an oscillator indicated by reference numeral 53 is disposed adjacent to the crystal resonator. An electronic component 54 such as a capacitor is also mounted. These components are electrically connected by a wiring pattern (not shown). The mechanical vibration of the piezoelectric vibrating piece of the tuning fork type crystal resonator 51 is converted into an electric signal by the piezoelectric characteristics of the crystal and input to the integrated circuit 53. In the integrated circuit 53, signal processing is performed, and a frequency signal is output to function as an oscillator. Each of these components is molded with a resin (not shown). By appropriately selecting the integrated circuit 53, in addition to the single-function oscillator for a clock, there are functions for controlling the operation date and time of the device and external device, and providing the user with time and calendar information.

  By using the piezoelectric vibrator manufactured by the manufacturing method of the present invention, it is possible to reduce the size of the vibrator having the largest volume among the components constituting the oscillator. Therefore, the external dimensions of the oscillator can be further reduced.

  As a seventh embodiment of the present invention, an electronic apparatus that uses the piezoelectric vibrator connected to a timer unit will be described with reference to FIG. As an example of an electronic device, a preferred embodiment in a portable information device represented by a mobile phone will be described in detail.

  First, as a premise, the portable information device according to the present embodiment is a development and improvement of a wrist watch in the prior art. The appearance is similar to that of a wristwatch, and a liquid crystal display is arranged in a portion corresponding to the dial so that the current time and the like can be displayed on this screen. When used as a communication device, it can be removed from the wrist and communicated in the same manner as a conventional mobile phone by a speaker and a microphone built in the band. However, it is much smaller and lighter than conventional mobile phones.

  Next, a functional configuration of the portable information device according to the embodiment of the present invention will be described with reference to the drawings. FIG. 9 is a block diagram functionally showing the configuration of the portable information device according to the present embodiment.

  In FIG. 9, reference numeral 101 denotes a power supply unit that supplies power to each functional unit described later, and is specifically realized by a lithium ion secondary battery. A control unit 102, a timing unit 103, a communication unit 104, a voltage detection unit 105, and a display unit 107, which will be described later, are connected in parallel to the power supply unit 101, and power is supplied from the power supply unit 101 to each functional unit.

  The control unit 102 controls each function unit to be described later, and controls operation of the entire system such as transmission and reception of audio data, measurement and display of the current time, and the like. Specifically, the control unit 102 is realized by a program written in advance in a ROM, a CPU that reads and executes the program, a RAM that is used as a work area of the CPU, and the like.

  The timer 103 includes an integrated circuit including an oscillation circuit, a register circuit, a counter circuit, an interface circuit, and the like, and a tuning fork type crystal resonator as shown in FIG. The mechanical vibration of the tuning fork type crystal resonator is converted into an electric signal by the piezoelectric characteristics of the crystal and input to an oscillation circuit formed by a transistor and a capacitor. The output of the oscillation circuit is binarized and counted by a register circuit and a counter circuit. Signals are transmitted to and received from the control unit through the interface circuit, and the current time, current date, or calendar information is displayed on the display unit 107.

  The communication unit 104 has functions similar to those of a conventional mobile phone, and includes a radio unit 104a, a voice processing unit 104b, an amplification unit 104c, a voice input / output unit 104d, a ring tone generation unit 104e, a switching unit 104f, and a call control memory. Part 104g and telephone number input part 104h.

  The wireless unit 104a transmits and receives various data such as voice data to and from the base station via the antenna. The audio processing unit 104b encodes / decodes an audio signal input from the radio unit 104a or an amplification unit 104c described later. The amplifying unit 104c amplifies the signal input from the audio processing unit 104b or the audio input / output unit 104d described later to a predetermined level. The voice input / output unit 104d is specifically a speaker and a microphone, and amplifies a ringtone and a received voice or collects a speaker voice.

  Also, the ring tone generator 104e generates a ring tone in response to a call from the base station. The switching unit 104f switches the amplifying unit 104c connected to the voice processing unit 104b to the ringing tone generating unit 104e only when an incoming call is received, so that the generated ringing tone is transmitted to the voice input / output unit 104d via the amplifying unit 104c. To be output.

  The call control memory 104g stores a program related to incoming / outgoing call control of communication. The telephone number input unit 104h is specifically composed of 0 to 9 number keys and some other keys, and inputs the telephone number of the destination.

  The voltage detection unit 105 detects the voltage drop and notifies the control unit 102 when the voltage applied to each functional unit including the control unit 102 by the power supply unit 101 falls below a predetermined value. To do. The predetermined voltage value is a value set in advance as a minimum voltage necessary for stably operating the communication unit 104, and is, for example, a voltage of about 3V. Upon receiving the voltage drop notification from the voltage detection unit 105, the control unit 102 prohibits the operations of the radio unit 104a, the voice processing unit 104b, the switching unit 104f, and the ring tone generation unit 104e. In particular, it is essential to stop the operation of the wireless unit 104a with high power consumption. At the same time, the display unit 107 displays that the communication unit 104 has become unusable due to insufficient battery power.

  The operation of the communication unit 104 can be prohibited by the functions of the voltage detection unit 105 and the control unit 102, and a message to that effect can be displayed on the display unit 107.

  As the present embodiment, the function of the communication unit can be stopped in a more complete form by providing the power cutoff unit 106 that can selectively cut off the power supply of the part related to the function of the communication unit.

  The display indicating that the communication unit 104 has become unusable may be made by a text message, but more intuitively by a method such as marking the phone icon on the display unit 107 with a cross (X). Good.

  By using the small piezoelectric vibrator manufactured by the manufacturing method of the present invention for a portable information device, the portable electronic device can be further reduced in size.

It is a schematic block diagram which shows the example of the airtight terminal which concerns on 1st Example of this invention. It is a schematic block diagram which shows the example of the airtight terminal which concerns on the 2nd Example of this invention. It is a schematic block diagram which shows the example of the airtight terminal which concerns on the 3rd Example of this invention. It is a figure explaining the example of the piezoelectric vibrating piece which concerns on the 4th Example of this invention. It is a schematic block diagram which shows the example of the piezoelectric vibrator which concerns on the 5th Example of this invention. It is a schematic diagram which shows the example of mounting of the piezoelectric vibrator regarding the 5th Example of this invention. It is a manufacturing flowchart of the piezoelectric vibrator which concerns on the 5th Example of this invention. It is a top view which shows an example of a structure of the oscillator which concerns on the 6th Example of this invention. It is a block diagram which shows one example of a structure of the electronic device which concerns on the 7th Example of this invention functionally. It is a schematic block diagram which shows the piezoelectric vibrator which consists of a conventional cylinder type package.

Explanation of symbols

1 Airtight terminal 2 Lead 2a Inner lead 2b Outer lead 3 Stem 3a Projection (inner lead side)
3b Projection (outer lead side)
4 Filling Material 5 Plating Layer 6 Piezoelectric Vibrating Piece 6a Vibrating Arm 6b Weight 7 Base 8 Excitation Electrode 9 Mount Pad (Connection Area)
9a Mount pad with large area 9b Mount pad with small area 10 Case 11a, 12a, 13a, 14a, 15a, 16a, 17a First lead 11b, 12b, 13b, 14b, 15b, 16b, 17b Second lead 18 Lead 20 Crystal 21 First layer metal film (underlying metal film)
22 Second-layer metal film 23 Weight metal film 25 Mounting substrate 26a Pattern 26b Pattern 27 Mounting solder 51 Tuning fork type crystal resonator 52 Substrate 53 Integrated circuit 54 Electronic component 101 Power supply unit 102 Control unit 103 Timing unit 104 Communication unit 104a Wireless Unit 104b audio processing unit 104c amplifying unit 104d audio input / output unit 104e ringing tone generation unit 104f switching unit 104g call control memory unit 104h telephone number input unit 105 voltage detection unit 106 power supply cutoff unit 107 display unit

Claims (6)

An annular stem;
A first lead disposed through the stem and electrically insulated from the stem;
A second lead disposed through the stem, mechanically fixed along the inner peripheral surface of the stem, and having electrical continuity with the stem ;
A filler for hermetically sealing the first lead and the second lead in the stem;
An airtight terminal characterized by comprising:   The hermetic terminal according to claim 1, wherein a cross-sectional area of the first lead is larger than a cross-sectional area of the second lead. A piezoelectric vibrating piece made of a piezoelectric material,
An excitation electrode that is formed on a surface of the piezoelectric vibrating piece and vibrates the piezoelectric vibrating piece;
A connection region connected to the excitation electrode and electrically conducting outside the piezoelectric vibrating piece;
3. The piezoelectric vibrating piece connected to the hermetic terminal according to claim 1 , wherein the shape of the connection region is asymmetric with respect to a longitudinal center line of the piezoelectric vibrating piece. The airtight terminal according to claim 1 or 2,
A piezoelectric vibrating piece joined to the first lead and the second lead of the hermetic terminal;
And said inserting the stem of the airtight terminal so as to cover the piezoelectric resonator element form an airtight space, the bottomed cylindrical to have a electrical continuity with said hermetic terminal case,
A piezoelectric vibrator characterized by comprising: An oscillator using the piezoelectric vibrator according to claim 4 as an oscillator connected to an integrated circuit. An electronic apparatus comprising the piezoelectric vibrator according to claim 4 connected to a time measuring unit.

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