JP5263777B2 - Manufacturing method of sealing can - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a sealed case with which air tightness in the sealed case can be maintained by suppressing creases generated on an inner circumferential surface of the sealed case, and to provide a piezoelectric vibrator, an oscillator, electronic equipment and a radio clock. <P>SOLUTION: There is provided the method of manufacturing the sealed case housing a piezoelectric vibrating piece inside in an air-tight sealed state. The method includes a plurality of drawing steps for setting a plate 50 to be worked into the case to a die 61 and pressing the plate into a die hole 63 of the die 61 by using a punch 62. In each drawing step, an inner diameter of the die hole 63 and an outer diameter of the punch 62 are set smaller than those in the preceding drawing step. Further, in each drawing step, clearance between a side surface of the punch 62 and an inner circumferential surface of the die hole 63 is set narrower than thickness of the plate 50 prior to drawing in the relevant drawing step. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

The present invention relates to a manufacturing how the sealing can.

  2. Description of the Related Art In recent years, a piezoelectric vibrator using a crystal or the like is used as a time source, a timing source such as a control signal, a reference signal source, and the like in mobile phones and portable information terminal devices. Various piezoelectric vibrators of this type are known. For example, one having a tuning fork type piezoelectric vibrating piece, one having a piezoelectric vibrating piece that vibrates in thickness and the like, and the like are known.

The piezoelectric vibrator described above includes a tuning fork-type piezoelectric vibrating piece, a plug, and a case (sealing can) that hermetically seals the piezoelectric vibrating piece together with the plug.
Here, the case is a bottomed cylindrical shape made of a white alloy made of an alloy such as copper (Cu) / nickel (Ni) / zinc (Zn). For example, the piezoelectric vibrating piece is accommodated inside the case in a vacuum. In this state, it is press-fitted into the stem outer periphery of the plug (see, for example, Patent Documents 1 and 2).

  Further, the case described above is generally formed into the above-described bottomed cylindrical shape by drawing a flat plate material. Specifically, the plate material set in the die is pushed into the die hole with a punch slightly smaller than the outer diameter of the case that is the product. Then, due to plastic deformation when the plate material is squeezed into the hole of the die, a compressive force is generated toward the inner side in the radial direction of the plate material, and a tensile force is generated along the axial direction, so that the inner diameter of the plate material is reduced and the axial direction is reduced. It will be stretched. In this case, when the axial length and inner diameter of the case are formed to be greater than or equal to the limit drawing of the plate material, the drawing process is divided into a plurality of stages and gradually reduced to obtain a product having a desired length and inner diameter. Techniques for manufacturing are also known (so-called redraw molding).

JP-A-5-167371 JP-A-5-183367

  By the way, in the drawing process described above, the clearance between the side surface of the punch and the inner peripheral surface of the die hole when the punch is pushed into the die hole is taken into consideration based on the plate thickness of the plate material in consideration of wear of the die and the punch. Is generally performed in a widely set state.

However, when the drawing is performed with the clearance set as described above, the inner peripheral surface of the case is satin-like due to the compressive force acting toward the inner side in the radial direction of the plate material and the tensile force acting along the axial direction. There is a problem that fine irregularities extending in the axial direction are generated. Furthermore, by carrying out multiple stages of drawing by redrawing as described above, the unevenness formed on the inner peripheral surface of the case becomes deeper in each process, and the convex portions adjacent in the circumferential direction overlap each other to form crack-like wrinkles There is a problem of being.
If crack-like wrinkles are generated in this way, the wrinkled portion may leak to the outside due to deterioration over time (so-called slow leak), and airtightness may not be maintained.

Then, this invention is made | formed in view of the problem mentioned above, the generation | occurrence | production of the flaw in the inner peripheral surface of a sealing can is suppressed, and the sealing can which can maintain the airtightness of a sealing can it is intended to provide a manufacturing how.

In order to solve the above-described problems, the present invention provides the following means.
A manufacturing method of a sealing can according to the present invention is a manufacturing method of a sealing can that stores an electronic component in an airtightly sealed state, and sets a plate material to be processed into the sealing can on a die, There are a plurality of squeezing steps to be pushed into the die hole of the die by punching, and in each squeezing step, the inner diameter of the die hole and the outer diameter of the punch are set smaller than in the preceding squeezing step, and each squeezing step Then, the clearance between the side surface of the punch and the inner peripheral surface of the die hole is set to be narrower than the plate thickness of the plate material before drawing in the drawing step.

According to this configuration, there is no space between the punch and the die hole at the time of drawing, so the axial direction of the die hole in the plate material is larger than the case where the clearance between both is formed wider than the thickness of the plate material It is possible to increase the tensile force and to reduce the compressive force in the radial direction. Further, when the plate material is pushed in, there is no space between the punch and the die for the plate material to rise radially inward and plastically deform. As a result, it is possible to suppress the occurrence of unevenness on the inner peripheral surface of the plate material, and to prevent these unevenness from overlapping each other in the drawing process and growing into wrinkles or cracks.
Furthermore, since the surface pressure acting on the plate material from the punch increases as compared with the conventional case, the surface of the punch is transferred to the inner peripheral surface of the plate material. That is, since the inner surface shape of the plate material is formed following the outer surface shape of the punch, it is also possible to suppress the generation of wrinkles and cracks on the inner peripheral surface of the plate material.
Therefore, even when the drawing process is performed in a plurality of stages, generation of wrinkles and cracks can be suppressed, and therefore a sealed can having a favorable inner peripheral surface shape and high airtightness can be manufactured. As a result, it is possible to prevent a slow leak that occurs due to deterioration over time of the sealing can.

According to the method for manufacturing a sealing can according to the present invention, even when the drawing process is performed in a plurality of stages, generation of wrinkles can be suppressed, so that the inner peripheral surface shape is good and the sealing is highly airtight. Cans can be manufactured .

It is the figure which looked at the content of the case of the piezoelectric vibrator of one Embodiment concerning this invention, Comprising: It is a figure of the state which planarly viewed the piezoelectric vibrating piece. It is the top view which looked at the piezoelectric vibrating piece shown in FIG. 1 from the upper surface. It is the top view which looked at the piezoelectric vibrating piece shown in FIG. 1 from the lower surface. It is sectional drawing which follows the AA line of FIG. FIG. 2 is a perspective view of the piezoelectric vibrating piece shown in FIG. 1. It is sectional drawing which follows the BB line of FIG. It is process drawing which shows the manufacturing method of a case. It is process drawing which shows the manufacturing method of a case. It is sectional drawing which shows the shape of the board | plate material before and behind each drawing process. It is a block diagram which shows one Embodiment of the oscillator which concerns on this invention. It is a block diagram which shows one Embodiment of the electronic device which concerns on this invention. It is a block diagram which shows one Embodiment of the radio timepiece which concerns on this invention.

Next, embodiments of the present invention will be described with reference to the drawings.
(Piezoelectric vibrator)
FIG. 1 is a perspective view of a piezoelectric vibrator according to this embodiment. As shown in FIG. 1, the piezoelectric vibrator 1 is a cylinder package type piezoelectric vibrator, and includes a tuning fork-type piezoelectric vibrating piece (electronic component) 2, a plug 4 on which the piezoelectric vibrating piece 2 is mounted, a plug 4 and a case (sealing can) 3 for hermetically sealing the piezoelectric vibrating piece 2.

2 is a plan view seen from the upper surface of the piezoelectric vibrating piece, and FIG. 3 is a plan view seen from the lower surface. 4 is a cross-sectional view taken along line AA in FIG. 2, and FIG. 5 is a perspective view of the piezoelectric vibrating piece.
As shown in FIGS. 2 and 3, the piezoelectric vibrating piece 2 is a tuning fork type vibrating piece formed of a piezoelectric material such as crystal, lithium tantalate, or lithium niobate, and vibrates when a predetermined voltage is applied. To do.
The piezoelectric vibrating piece 2 includes a pair of vibrating arm portions 8 and 9 arranged in parallel, a base portion 10 that integrally fixes the base end sides of the pair of vibrating arm portions 8 and 9, and a pair of vibrating arm portions. An excitation electrode 14 comprising a first excitation electrode 12 and a second excitation electrode 13 which are formed on the outer surfaces of 8, 9 and vibrate the pair of vibrating arm portions 8 and 9, a first excitation electrode 12 and The mounting electrodes 15 and 16 are electrically connected to the second excitation electrode 13.
Further, the piezoelectric vibrating reed 2 of the present embodiment is formed with a certain length L on both main surfaces of the pair of vibrating arm portions 8 and 9 from the base end portion to the distal end portion of the vibrating arm portions 8 and 9. A groove portion 17 is provided. As shown in FIG. 4, the groove portion 17 is formed from the base end portions of the vibrating arm portions 8 and 9 to approximately the middle. Note that the arm widths of the pair of vibrating arm portions 8 and 9 are the same and are each W. Further, a portion of the base portion 10 connected to the base end portions of the pair of vibrating arm portions 8 and 9 is referred to as a crotch portion 10a.

  As shown in FIGS. 2, 3, and 5, the excitation electrode 14 including the first excitation electrode 12 and the second excitation electrode 13 has a predetermined direction in a direction in which the pair of vibrating arm portions 8 and 9 approach or separate from each other. It is an electrode that vibrates at a resonance frequency, and is formed by patterning the outer surfaces of the pair of vibrating arm portions 8 and 9 in a state of being electrically separated from each other. Specifically, the first excitation electrode 12 is mainly formed on the groove portion 17 of one vibration arm portion 8 and on both side surfaces of the other vibration arm portion 9, and the second excitation electrode 13 is It is mainly formed on both side surfaces of one vibrating arm portion 8 and on the groove portion 17 of the other vibrating arm portion 9.

  In addition, as shown in FIGS. 2 and 3, the first excitation electrode 12 and the second excitation electrode 13 are formed continuously on both main surfaces of the base 10, and are respectively connected via extraction electrodes 19 and 20. Are electrically connected to the mount electrodes 15 and 16. The mount electrodes 15 and 16 are formed on the proximal end side of the piezoelectric plate 11. That is, the excitation electrode 14, the mount electrodes 15 and 16, and the extraction electrodes 19 and 20 function as an electrode film 18 that vibrates the pair of vibrating arm portions 8 and 9 when a predetermined voltage is applied.

  As shown in FIG. 4, the electrode film 18 is formed in a state where a base metal layer 18a and a finish metal layer 18b are laminated in two layers. In the present embodiment, chromium is used for the base metal layer 18a and gold is used for the finish metal layer 18b. However, the present invention is not limited to this. For example, you may form with the film of other electroconductive films, such as nickel (Ni), aluminum (Al), and titanium (Ti).

  Further, as shown in FIG. 5, the electrode film 18 has a part or all of the finish metal layer 18b removed at least in the region from the base end portion to the tip end portion of the vibrating arm portions 8 and 9. More specifically, on the distal end side from the proximal end portions of the vibrating arm portions 8 and 9, to a position separated from the proximal end portion by a certain length L (region RA shown in FIG. 5), as shown in FIG. All of the metal layer 18b is removed. Furthermore, from the base end part of the vibrating arm parts 8 and 9 to the base part 10 side, the base arm part 10 is moved to the base part 10 until reaching a position separated by twice the arm width W of the vibrating arm parts 8 and 9 (FIG. 5). And the finish metal layer 18b is completely removed.

That is, the electrode film 18 is a region RA and a region RB including the region where the groove portion 17 of the vibrating arm portions 8 and 9 is formed, and the entire surface including the inside of the groove portion 17 is a single-layer film including only the base metal layer 18a. Become. An insulating film (not shown) made of silicon oxide (SiO ₂ ) or the like is covered on the base metal layer 18a in the region RA and the region RB. In the following, the region including the region RA and the region RB will be described as a single layer region R.

  Further, as shown in FIGS. 2 and 3, weights for adjusting (frequency adjustment) to vibrate their own vibration state within a predetermined frequency range are provided at the ends of the pair of vibrating arm portions 8 and 9, respectively. A metal film 21 is coated. The weight metal film 21 is divided into a coarse adjustment film 21a used when the frequency is roughly adjusted and a fine adjustment film 21b used when the frequency is finely adjusted. By adjusting the frequency using the coarse adjustment film 21a and the fine adjustment film 21b, the frequency of the pair of vibrating arm portions 8 and 9 can be within the range of the nominal frequency of the device.

  Here, as shown in FIG. 1, the case 3 is formed in a bottomed cylindrical shape made of white or white, which is an alloy such as copper / nickel / zinc, and its axial direction and the longitudinal direction of the piezoelectric vibrating piece 2 The piezoelectric vibrating reed 2 is housed inside in a state where these are matched. In this state, the case 3 is press-fitted into an outer periphery of a stem 30 to be described later of the plug 4 and is fixedly fitted. The press-fitting of the case 3 is performed in a vacuum atmosphere, and the space surrounding the piezoelectric vibrating piece 2 in the case 3 is kept in a vacuum.

The plug 4 is arranged in parallel so as to pass through the stem 30 that seals the case 3, and the piezoelectric vibrating reed 2 is mounted on one end side with the stem 30 interposed therebetween (mechanically joined and electrically connected). The inner lead 31a is connected to the outside, and the other end is electrically connected to the outside. The two lead terminals 31 are electrically connected to the outside, and the stem 30 and the lead terminal 31 are fixed by being filled inside the stem 30. And an insulating filler 32 to be made.
The stem 30 is formed of a metal material in an annular shape. The material of the filler 32 is, for example, borosilicate glass. Further, the surface of the lead terminal 31 and the outer periphery of the stem 30 are respectively plated with the same material (not shown).

  In the two lead terminals 31, a portion protruding into the case 3 is an inner lead 31 a and a portion protruding outside the case 3 is an outer lead 31 b. The inner lead 31a and the mount electrodes 15 and 16 are mounted via conductive bumps E. That is, the inner lead 31a and the mount electrodes 15 and 16 are mechanically bonded via the bump E and at the same time are electrically connected. As a result, the piezoelectric vibrating piece 2 is mounted on the two lead terminals 31.

  The two lead terminals 31 described above have one end side (outer lead 31 b side) electrically connected to the outside and the other end side (inner lead 31 a side) mounted externally to the piezoelectric vibrating piece 2. Functions as a connection terminal.

Here, an example of dimensions and materials of the main parts constituting the plug 4 will be described.
The diameter of the lead terminal 31 is about 0.12 mm, for example, and Kovar (FeNiCo alloy) is commonly used as the material of the base material of the lead terminal 31. In addition, as a plating material to be coated on the outer surface of the lead terminal 31 and the outer periphery of the stem 30, Cu is used as a base film, and a heat-resistant solder plating (an alloy of tin and lead with a weight ratio thereof) is used as a finishing film. 1: 9), silver (Ag), tin-copper alloy (SnCu), gold-tin alloy (AuSn), or the like.
Further, the inside of the case 3 can be hermetically sealed in a vacuum state by cold-welding the inner periphery of the case 3 in vacuum while interposing a metal film (plating layer) coated on the outer periphery of the stem 30. It has become.

  When the piezoelectric vibrator 1 configured as described above is operated, a predetermined drive voltage is applied to the outer leads 31 b of the two lead terminals 31. As a result, a current can flow to the excitation electrode 14 including the first excitation electrode 12 and the second excitation electrode 13 via the inner lead 31a, the bump E, the mount electrodes 15 and 16, and the extraction electrodes 19 and 20. The pair of vibrating arm portions 8 and 9 can be vibrated at a predetermined frequency in a direction in which the pair of vibrating arm portions 8 and 9 are approached or separated. The vibration of the pair of vibrating arm portions 8 and 9 can be used as a time source, a control signal timing source, a reference signal source, or the like.

(Piezoelectric vibrator manufacturing method)
Next, a method for manufacturing the above-described piezoelectric vibrator will be described. In the following description, a method for manufacturing the case described above will be mainly described. 7 and 8 are process diagrams showing a manufacturing method of the case, and FIG. 9 is a cross-sectional view showing the shape of the plate material before and after each drawing process.
The case 3 (see FIG. 1) of the present embodiment has a bottomed cylindrical shape that is long in the axial direction by converting a flat plate material 50 (for example, thickness T) made of white and white through a plurality of drawing steps. The case 3 can be formed.

(Drawing equipment)
First, the drawing apparatus used in the drawing process will be described with reference to FIG.
As shown in FIG. 7A, the drawing device 60 includes a die 61 and a punch 62.
The die 61 is configured to have a rectangular parallelepiped appearance, and the upper surface thereof is a mounting surface 61 a of the plate member 50. A die hole 63 is formed in the center portion of the mounting surface 61a along the height direction. The die hole 63 is a hole in which the opening is formed in a circular shape and the plate material 50 is pushed in, and a constricted portion 64 is formed on the opening edge side. The constricted portion 64 includes a reduced diameter portion 65 whose inner diameter is gradually reduced from the opening edge, a narrowed portion 66 formed with a uniform inner diameter along the height direction from the tip of the reduced diameter portion 65, and a narrowed portion 66. And an enlarged-diameter portion 67 whose inner diameter is gradually enlarged from the tip. In addition, the corner | angular part of the opening edge of the die hole 63 and the boundary part of the constriction part 64 comprise the curved surface of a predetermined curvature radius.

  On the other hand, the punch 62 is a columnar member having an outer diameter smaller than the inner diameter of the narrowed portion 66 of the constricted portion 64 and having a good surface roughness, and the corner portion of the tip end surface has a predetermined radius of curvature. Constructs a curved surface. The punch 62 can be reciprocated at a predetermined stroke along the axial direction by a moving mechanism (not shown). In the drawing process described later, the punch 62 is inserted into the die hole 63 of the die 61 with the plate member 50 interposed therebetween. It is supposed to be pushed in.

  Here, as shown in FIG. 7B, the clearance Q between the side surface of the punch 62 and the inner peripheral surface of the throttle portion 66 of the die 61 when the punch 62 is pushed into the die hole 63 is the same as that before drawing. It is set narrower than the thickness T (see FIG. 7A) of the plate material 50 (for example, when flat) (Q <T). That is, no gap is generated between the narrowed portion 66 and the punch 62 during the narrowing process. In each drawing step described later, a plurality of (for example, two) drawing devices having different sizes are used. However, the drawing steps are substantially the same except for the sizes such as the inner diameter of the die hole 63 and the outer diameter of the punch 62. The same reference numerals are given and the description is omitted.

(Drawing process)
Next, each drawing process for manufacturing the case described above will be specifically described.
First, as shown in FIG. 7A, the plate material 50 is subjected to a first drawing process to form a bottomed cylindrical (bowl-shaped) plate material 50a (see FIG. 9B) that is shallow from the flat plate. (First drawing step). Specifically, the above-described plate material 50 having a thickness T made of white and white is prepared, and a die (hereinafter referred to as a first die 61) of a drawing device (hereinafter referred to as a first drawing device 60) used for the first drawing. On the mounting surface 61a. At this time, the center in the surface direction of the plate member 50 is set on the mounting surface 61 a of the first die 61 in a state in which the center in the surface direction coincides with the center of the die hole 63.

Subsequently, when the punch 62 is lowered with a predetermined stroke (see the white arrow G in FIG. 7), the tip end surface of the punch 62 first comes into contact with the surface of the plate member 50. Then, as shown in FIG. 7B, by further lowering the punch 62, the plate member 50 is sandwiched between the punch 62 and the die 61 so that the plate member 50 has the outer surface shape of the punch 62 and the die hole 63. The inside of the die hole 63 is narrowed down following the shape of the inner surface.
Specifically, a compressive force acts on the plate member 50 squeezed into the die hole 63 toward the inside in the radial direction of the die hole 63, and the outer peripheral portion thereof is directed upward following the shape of the reduced diameter portion 65. Then, it bends as if it gets up (see the arrow in FIG. 7B). Further, when the punch 62 is pushed into the die hole 63 on the plate member 50, a tensile force acts along the axial direction of the die hole 63, and the plate member 50 extends along the axial direction. Thereafter, when the diaphragm portion 66 is further narrowed down, the center portion of the plate member 50 forms a bottom surface and the outer peripheral portion forms a circumferential surface, and the bottom surface and the circumferential surface are formed in a bowl shape so as to be approximately 90 degrees. Thus, the first drawing step is completed, and the plate member 50 is formed into a bowl-like plate member 50a as shown in FIG. 9B from the flat plate state as shown in FIG. 9A.

Here, in the first drawing process of the present embodiment, the clearance Q between the punch 62 of the drawing device 60 and the die 61 is set to be narrower than the thickness T of the plate material 50 before drawing. There is no space between 62 and the die hole 63. Thereby, compared with the case where the clearance Q is formed wider than the thickness T of the plate material 50, the plate material 50 is pushed more strongly into the die hole 63, so that the tensile force in the axial direction of the die hole 63 in the plate material 50 is increased. Can be increased and the compressive force in the radial direction can be reduced. Further, when the plate member 50 is pushed in, there is no space for the plate member 50 to be plastically deformed in the radial direction between the punch 62 and the die 61. As a result, the inner peripheral surface of the plate member 50 does not rise toward the inner side in the radial direction, and it is possible to suppress the occurrence of unevenness on the inner peripheral surface of the plate member 50.
Further, since the surface pressure acting on the plate member 50 from the punch 62 is increased as compared with the conventional case, the surface of the punch 62 is transferred to the inner peripheral surface of the plate member 50. That is, since the inner surface shape of the plate material 50 is formed following the outer surface shape of the punch 62, the occurrence of irregularities on the inner peripheral surface of the plate material 50 can also be suppressed.

Next, the bowl-shaped plate material 50a is drawn again to reduce the inner diameter of the plate material 50a and extend the length in the axial direction (second drawing process). Note that the second drawing device 60 used in the second drawing step is different from the inner diameter R1 (see FIG. 7A) of the die hole 63 of the first drawing device 60 and the outer diameter of the punch 62 described above. The inner diameter R2 of the hole 63 and the outer diameter of the punch 62 are set small, and the rest of the configuration is substantially the same.
First, as shown in FIG. 8A, the bowl-shaped plate material 50a formed in the first drawing process is set on the die 61 of the second drawing apparatus 60 in the same manner as in the first drawing process described above. .

  Subsequently, when the punch 62 is lowered with a predetermined stroke (see the white arrow G in FIG. 8), the tip surface of the punch 62 first comes into contact with the surface of the plate member 50a. Then, as shown in FIG. 8B, by further lowering the punch 62, the plate material 50a follows the outer surface shape of the punch 62 and the inner surface shape of the die hole 63, and enters the die hole 63 while reducing the inner diameter. It will be narrowed down. As a result, the plate member 50a is formed into a cylindrical shape having a reduced inner diameter as shown in FIG. 9C and extending in the axial direction from a shallow bowl-like state as shown in FIG. 9B. The The plate thickness T of the plate material (for example, the plate material 50a) after each drawing step is slightly different in the surface direction of the plate material, but is equal to the plate thickness T of the flat plate material 50 on average.

  Here, in the present embodiment, the clearance Q between the punch 62 and the die 61 of the drawing device 60 is set to be narrower than the thickness T of the plate material 50a before drawing in each drawing process. As described above, the occurrence of unevenness on the inner peripheral surface of the plate member 50b can be suppressed. That is, since it is possible to suppress the occurrence of unevenness on the inner peripheral surface of the plate material 50b (50a, 50) in each drawing step, it is possible to suppress the protrusions adjacent in the circumferential direction from overlapping and growing into wrinkles or cracks. . As a result, the case 3 having a good inner peripheral surface shape and high airtightness can be manufactured.

  As shown in FIG. 9C, by adjusting the stroke of the punch 62, the opening side of the plate material 50 c is formed in a funnel shape following the reduced diameter portion 65 of the die hole 63. Therefore, the opening end of the plate member 50c is cut in a direction orthogonal to the axial direction after the second drawing step. Thereby, the case 3 described above is completed.

On the other hand, before the piezoelectric vibrating piece 2 is hermetically sealed, the piezoelectric vibrating piece 2 and the plug 4 are electrically connected.
Specifically, first, a mounting process for bonding the mount electrodes 15 and 16 of the piezoelectric vibrating piece 2 to the inner lead 31a is performed. Specifically, while heating the bump E, the inner lead 31a and the piezoelectric vibrating piece 2 are superposed at a predetermined pressure with the bump E sandwiched therebetween. Thus, the inner lead 31a and the mount electrodes 15 and 16 can be connected via the bump E. As a result, the piezoelectric vibrating piece 2 can be mounted. That is, the piezoelectric vibrating piece 2 is mechanically supported by the lead terminals 31 and is electrically connected.
In addition, when bump connection is performed by heating and pressurization, the bump connection may be performed using ultrasonic waves.

Subsequently, after adjusting the frequency (fine adjustment) of the piezoelectric vibrating piece 2, the case 3 manufactured by the above-described manufacturing method is press-fitted into the stem 30 so that the mounted piezoelectric vibrating piece 2 is housed inside. Then, a case press-fitting step for hermetically sealing the piezoelectric vibrating piece 2 is performed. Specifically, the case 3 is press-fitted into the outer periphery of the stem 30 of the plug 4 while applying a predetermined load in a vacuum. Then, since the metal film formed on the outer periphery of the stem 30 is elastically deformed, it can be hermetically sealed by cold pressure welding. Thereby, the piezoelectric vibrating piece 2 can be sealed and vacuum-sealed in the case 3.
In addition, before performing this process, it is preferable that the piezoelectric vibrating piece 2, the case 3 and the plug 4 are sufficiently heated to desorb moisture adsorbed on the surface and the like.

Then, after the case 3 is fixed, screening is performed. This screening is performed in order to stabilize the frequency and the resonance resistance value and to suppress the occurrence of metal whisker due to the compressive stress in the fitting portion into which the case 3 is press-fitted.
After screening, the internal electrical characteristics are inspected. That is, the resonance frequency, resonance resistance value, drive level characteristic (excitation power dependence of the resonance frequency and resonance resistance value), etc. of the piezoelectric vibrating piece 2 are measured and checked. In addition, the insulation resistance characteristics and the like are also checked. Finally, an appearance inspection of the piezoelectric vibrator 1 is performed to finally check dimensions, quality, and the like. As a result, the piezoelectric vibrator 1 shown in FIG. 1 can be manufactured.

Thus, in the present embodiment, in the drawing process of the case 3, the clearance Q between the punch 62 and the die hole 63 used in each drawing process is set to the plate thickness of the plate material (for example, the plate materials 50 and 50a) before drawing. It was set as the structure set narrower than T.
According to this configuration, since no space is generated between the punch 62 and the die hole 63 during the drawing, the clearance Q between the two is greater in the plate material than in the case where the clearance Q is formed wider than the thickness T of the plate material. While increasing the tensile force in the axial direction of the die hole 63, the compressive force in the radial direction can be reduced. Further, when the plate material is pushed in, there is no space between the punch 62 and the die 61 for the plate material to rise radially inward and plastically deform. As a result, it is possible to suppress the occurrence of unevenness on the inner peripheral surface of the plate material, and to suppress the convex portions adjacent in the circumferential direction from overlapping each other in the drawing process and growing into wrinkles or cracks.
Furthermore, since the surface pressure acting on the plate material from the punch 62 increases as compared with the conventional case, the surface of the punch 62 is transferred to the inner peripheral surface of the plate material. That is, since the inner surface shape of the plate material is formed following the outer surface shape of the punch 62, it is also possible to suppress the occurrence of wrinkles and cracks on the inner peripheral surface of the plate material.
Therefore, even when the drawing process is performed in a plurality of stages, since the occurrence of wrinkles and cracks can be suppressed in each drawing process, the case 3 having a good inner surface shape and high airtightness can be manufactured. As a result, it is possible to prevent a slow leak that occurs due to deterioration of the case 3 over time. Then, the piezoelectric vibrating reed 2 is hermetically sealed using the case 3 manufactured in this way, whereby the highly accurate piezoelectric vibrator 1 that is stable over a long period of time can be provided.

(Oscillator)
Next, an embodiment of an oscillator according to the present invention will be described with reference to FIG.
As shown in FIG. 10, the oscillator 100 according to the present embodiment is configured such that the piezoelectric vibrator 1 is an oscillator electrically connected to the integrated circuit 101. The oscillator 100 includes a substrate 103 on which an electronic component 102 such as a capacitor is mounted. On the substrate 103, the above-described integrated circuit 101 for the oscillator is mounted, and the piezoelectric vibrator 1 is mounted in the vicinity of the integrated circuit 101. The electronic component 102, the integrated circuit 101, and the piezoelectric vibrator 1 are electrically connected by a wiring pattern (not shown). Each component is molded with a resin (not shown).

In the oscillator 100 configured as described above, when a voltage is applied to the piezoelectric vibrator 1, the piezoelectric vibrating piece 2 in the piezoelectric vibrator 1 vibrates. This vibration is converted into an electric signal by the piezoelectric characteristics of the piezoelectric vibrating piece 2 and input to the integrated circuit 101 as an electric signal. The input electrical signal is subjected to various processes by the integrated circuit 101 and is output as a frequency signal. Thereby, the piezoelectric vibrator 1 functions as an oscillator.
Further, by selectively setting the configuration of the integrated circuit 101, for example, an RTC (real-time clock) module or the like according to a request, the operation date and time of the device and the external device in addition to a single-function oscillator for a clock, etc. A function for controlling the time, providing a time, a calendar, and the like can be added.

  As described above, according to the oscillator 100 of this embodiment, since the high-quality piezoelectric vibrator 1 is provided, the quality of the oscillator 100 itself can be improved in the same manner. In addition to this, it is possible to obtain a highly accurate frequency signal that is stable over a long period of time.

(Electronics)
Next, an embodiment of an electronic apparatus according to the present invention will be described with reference to FIG. Note that the portable information device 110 having the above-described piezoelectric vibrator 1 will be described as an example of the electronic device. First, the portable information device 110 according to the present embodiment is represented by, for example, a mobile phone, and is a development and improvement of a wrist watch in the related art. The appearance is similar to that of a wristwatch, and a liquid crystal display is arranged in a portion corresponding to a dial so that the current time and the like can be displayed on this screen. Further, when used as a communication device, it is possible to perform communication similar to that of a conventional mobile phone by using a speaker and a microphone that are removed from the wrist and incorporated in the inner portion of the band. However, it is much smaller and lighter than conventional mobile phones.

  Next, the configuration of the portable information device 110 of this embodiment will be described. As shown in FIG. 11, the portable information device 110 includes the piezoelectric vibrator 1 and a power supply unit 111 for supplying power. The power supply unit 111 is made of, for example, a lithium secondary battery. The power supply unit 111 includes a control unit 112 that performs various controls, a clock unit 113 that counts time, a communication unit 114 that communicates with the outside, a display unit 115 that displays various types of information, A voltage detection unit 116 that detects the voltage of the functional unit is connected in parallel. The power unit 111 supplies power to each functional unit.

  The control unit 112 controls each function unit to control operation of the entire system such as transmission and reception of audio data, measurement and display of the current time, and the like. The control unit 112 includes a ROM in which a program is written in advance, a CPU that reads and executes the program written in the ROM, and a RAM that is used as a work area of the CPU.

  The timer unit 113 includes an integrated circuit including an oscillation circuit, a register circuit, a counter circuit, an interface circuit, and the like, and the piezoelectric vibrator 1. When a voltage is applied to the piezoelectric vibrator 1, the piezoelectric vibrating piece 2 vibrates, and this vibration is converted into an electric signal by the piezoelectric characteristics of the crystal and input to the oscillation circuit as an electric signal. The output of the oscillation circuit is binarized and counted by a register circuit and a counter circuit. Then, signals are transmitted to and received from the control unit 112 via the interface circuit, and the current time, current date, calendar information, or the like is displayed on the display unit 115.

The communication unit 114 has functions similar to those of a conventional mobile phone, and includes a radio unit 117, a voice processing unit 118, a switching unit 119, an amplification unit 120, a voice input / output unit 121, a telephone number input unit 122, and a ring tone generation unit. 123 and a call control memory unit 124.
The wireless unit 117 exchanges various data such as audio data with the base station via the antenna 125. The audio processing unit 118 encodes and decodes the audio signal input from the radio unit 117 or the amplification unit 120. The amplifying unit 120 amplifies the signal input from the audio processing unit 118 or the audio input / output unit 121 to a predetermined level. The voice input / output unit 121 includes a speaker, a microphone, and the like, and amplifies a ringtone and a received voice or collects a voice.

In addition, the ring tone generator 123 generates a ring tone in response to a call from the base station. The switching unit 119 switches the amplifying unit 120 connected to the voice processing unit 118 to the ringing tone generating unit 123 only when an incoming call is received, so that the ringing tone generated in the ringing tone generating unit 123 is transmitted via the amplifying unit 120. To the audio input / output unit 121.
The call control memory unit 124 stores a program related to incoming / outgoing call control of communication. The telephone number input unit 122 includes, for example, a number key from 0 to 9 and other keys. By pressing these number keys and the like, a telephone number of a call destination is input.

  When the voltage applied to each functional unit such as the control unit 112 by the power supply unit 111 falls below a predetermined value, the voltage detection unit 116 detects the voltage drop and notifies the control unit 112 of the voltage drop. . The predetermined voltage value at this time is a value set in advance as a minimum voltage necessary for stably operating the communication unit 114, and is, for example, about 3V. Upon receiving the voltage drop notification from the voltage detection unit 116, the control unit 112 prohibits the operations of the radio unit 117, the voice processing unit 118, the switching unit 119, and the ring tone generation unit 123. In particular, it is essential to stop the operation of the wireless unit 117 with high power consumption. Further, the display unit 115 displays that the communication unit 114 has become unusable due to insufficient battery power.

That is, the operation of the communication unit 114 can be prohibited by the voltage detection unit 116 and the control unit 112, and that effect can be displayed on the display unit 115. This display may be a text message, but as a more intuitive display, a x (X) mark may be attached to the telephone icon displayed at the top of the display surface of the display unit 115.
In addition, the function of the communication part 114 can be stopped more reliably by providing the power supply cutoff part 126 that can selectively cut off the power of the part related to the function of the communication part 114.

  As described above, according to the portable information device 110 of the present embodiment, since the quality-enhanced piezoelectric vibrator 1 is provided, the quality of the portable information device itself can be improved as well. In addition to this, it is possible to display highly accurate clock information that is stable over a long period of time.

(Radio watch)
Next, an embodiment of a radio timepiece according to the present invention will be described with reference to FIG.
As shown in FIG. 12, the radio-controlled timepiece 130 according to the present embodiment includes the piezoelectric vibrator 1 electrically connected to the filter unit 131. The radio-controlled timepiece 130 receives a standard radio wave including timepiece information and is accurate. It is a clock with a function of automatically correcting and displaying the correct time.
In Japan, there are transmitting stations (transmitting stations) that transmit standard radio waves in Fukushima Prefecture (40 kHz) and Saga Prefecture (60 kHz), each transmitting standard radio waves. Long waves such as 40 kHz or 60 kHz have the property of propagating the surface of the earth and the property of propagating while reflecting the ionosphere and the surface of the earth, so the propagation range is wide, and the above two transmitting stations cover all of Japan. doing.

Hereinafter, the functional configuration of the radio timepiece 130 will be described in detail.
The antenna 132 receives a long standard wave of 40 kHz or 60 kHz. The long-wave standard radio wave is obtained by subjecting time information called a time code to AM modulation on a 40 kHz or 60 kHz carrier wave. The received long standard wave is amplified by the amplifier 133 and filtered and tuned by the filter unit 131 having the plurality of piezoelectric vibrators 1.
The piezoelectric vibrator 1 in this embodiment includes crystal vibrator portions 138 and 139 having resonance frequencies of 40 kHz and 60 kHz that are the same as the carrier frequency described above.

Further, the filtered signal having a predetermined frequency is detected and demodulated by the detection and rectification circuit 134.
Subsequently, the time code is taken out via the waveform shaping circuit 135 and counted by the CPU 136. The CPU 136 reads information such as the current year, accumulated date, day of the week, and time. The read information is reflected in the RTC 137, and accurate time information is displayed.
Since the carrier wave is 40 kHz or 60 kHz, the crystal vibrator units 138 and 139 are preferably vibrators having the tuning fork type structure described above.

  In addition, although the above-mentioned description was shown in the example in Japan, the frequency of the long standard wave is different overseas. For example, in Germany, a standard radio wave of 77.5 KHz is used. Accordingly, when the radio timepiece 130 that can be used overseas is incorporated in a portable device, the piezoelectric vibrator 1 having a frequency different from that in Japan is required.

  As described above, according to the radio timepiece 130 of the present embodiment, since the high quality piezoelectric vibrator 1 is provided, the quality of the radio timepiece itself can be improved in the same manner. In addition to this, it is possible to count time stably and with high accuracy over a long period of time.

As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.
For example, in the above-described embodiment, the cylinder package type piezoelectric vibrator 1 is described as an example of the piezoelectric vibrator, but the piezoelectric vibrator 1 is not limited thereto. For example, a ceramic package type piezoelectric vibrator or a cylinder package type piezoelectric vibrator 1 may be further solidified with a mold resin portion to form a surface mount vibrator. Further, not only the piezoelectric vibrator but also a case manufactured by the above-described manufacturing method may be used when various electronic components are hermetically sealed. In this case, the material for manufacturing the case is not limited to the white, and various materials can be selected and used.

  In the above-described embodiment, the case where the drawing process is performed in two stages on the plate material has been described. However, the inner diameter of the die hole 63 and the outer diameter of the punch 62 are gradually reduced as compared with the previous drawing process, and If the clearance Q of the drawing device 60 used in the drawing process is set to be narrower than the plate thickness T of the plate material before drawing, it may be performed not only in two steps but also in three or more steps.

DESCRIPTION OF SYMBOLS 1 ... Piezoelectric vibrator 2 ... Piezoelectric vibration piece (electronic component) 3 ... Case (sealing can) 50, 50a, 50b ... Plate material 61 ... Die 62 ... Punch 63 ... Die hole 100 ... Oscillator 101 ... Oscillator integrated circuit 110 ... Portable information device (electronic device) 113 ... Timekeeping unit of electronic device 130 ... Radio clock 131 ... Filter unit of radio clock

Claims (1)

It is a manufacturing method of a sealing can that stores an electronic component in an airtightly sealed state inside,
The plate material to be processed into the sealing can is set in a die, and has a plurality of drawing steps to be pushed into the die hole of the die by punching,
In each drawing step, the inner diameter of the die hole and the outer diameter of the punch are set smaller than the drawing step in the previous stage,
In each of the drawing processes, a clearance between a side surface of the punch and an inner peripheral surface of the die hole is set to be narrower than a plate thickness of the plate material before drawing in the drawing process. Manufacturing method.

Images