JP2009088896A - Surface-mounted type crystal vibrator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-mounted type crystal vibrator which is excellently resin-molded without deforming a sealing tube of a crystal vibrator. <P>SOLUTION: A cylinder type crystal vibrator 7 is constituted such that a sealing tube 7a and a lead terminal 7b led out of one end side thereof are fixed to a lead frame 3 by a means for soldering etc. The crystal vibrator 7 fixed to and held by the lead frame 3 is clamped with vertically disposed injection molding metal molds and a resin is injected inside the metal molds and hardened to obtain a surface-mounted type crystal vibrator 10. A top surface portion of the sealing tube 7a has a projection portion 7c directed to outside the sealing tube 7a and is formed in a shape which is not a flat surface. Consequently, pressure that the top surface portion receives owing to injection pressure of the resin injected during injection molding can be dispersed to prevent the top surface portion from deforming. Consequently, the excellent surface-mounted type crystal vibrator is obtained. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a surface-mount type crystal resonator.

  In general, a resin-molded surface-mount type crystal resonator has its crystal tube sealed on the surface of the mold resin when it is injection-molded after the terminals of the crystal resonator are fixed (welded) to the lead frame. In order to avoid this, a pin for positioning and fixing the sealing tube of the crystal resonator is provided in the injection mold so that the crystal resonator does not move during injection molding.

  FIG. 3 is a perspective view of a surface-mount type crystal resonator manufactured by a conventional technique, FIG. 4 is a view of the surface-mount type crystal resonator of FIG. 3 viewed from three directions, and (a) is a front view. (B) is a top view and (c) is a side view. 3 and 4 indicate the external shape of the internal crystal unit.

  Reference numeral 2 denotes a cylinder-type crystal resonator (hereinafter simply referred to as a crystal resonator), in which a sealing tube 2a and a lead terminal 2b led out from one end thereof are fixed to the lead frame 3 by means such as welding. The crystal resonator 2 fixedly held on the lead frame 3 is sandwiched between injection molds arranged in the vertical direction, and a surface-mounted crystal resonator 1 is formed by injecting and solidifying resin into the mold. In addition, after resin molding, a part of the lead frame 3 protruding to the outside is bent along the outer shape of the surface-mounted crystal resonator to form an external connection terminal 3a.

FIG. 5 is a front sectional view showing the positional relationship between the mold and the crystal unit during the manufacturing process of the surface-mount type crystal unit.
Reference numeral 4 denotes an upper die, and 5 denotes a lower die, each having a recess for accommodating the crystal resonator 2. The upper die 4 and the lower die 5 are combined so that the crystal resonator 2 is sandwiched from above and below the crystal resonator 2, and the crystal resonator 2 is a concave space formed by the upper die 4 and the lower die 5. Placed inside.

  The injection-molded resin gate port 6 is provided in a part of the mating surface of the upper mold 4 and the lower mold 5, and is provided at a position on the lead terminal 2 b side of the crystal resonator 2. Resin is injected from the gate port 6 with a constant pressure (injection pressure), filled in the space in the upper mold 5 and the lower mold 6 and the outer peripheral portion of the crystal unit 2 is completely covered with resin.

  When the resin is injected with the above-described configuration, the sealing tube 2a of the crystal unit 2 is pushed in either the vertical direction by the injection pressure of the resin, and comes into contact with the upper mold 4 or the lower mold 5 to perform surface mounting. When the quartz crystal resonator 1 is completed, the sealing tube 2a is exposed on the outer surface. In order to avoid this, if the distance between the outer surface of the sealing tube 2a and the dies 4 and 5 is increased, the exposure of the sealing tube 2a can be prevented, but the thickness of the surface-mounted crystal resonator 1 increases. This is a measure that cannot be adopted when downsizing of electronic components is desired. For this reason, pins 4a for positioning and fixing the crystal unit 2 are arranged in the vertical direction of the sealing tube 2a of the crystal unit 2 and injection molding is performed. With this configuration, the surface of the resin-molded surface is formed in a state where the marks of the positioning and fixing pins 4a reach the sealing tube 2a of the crystal unit 2 as holes 4a '. In FIG. 5, since the pins 4a are arranged only on the upper mold 4, the resin-molded surface-mounted crystal resonator 1 shown in FIGS. 3 and 4 has two holes 4a ′ only on the upper surface. is there. (See Patent Document 1)

JP-A-9-139648

By the way, the injection pressure of the resin to be injected at the time of injection molding differs depending on the resin material to be selected. For example, when a thermoplastic resin (liquid crystal polymer) is used, the injection pressure at the stage of injection into the mold is used. Is about 650 kg / cm ² . Therefore, when the resin is injected with such a high injection pressure, there is a concern about the positional deviation of the crystal resonator that receives the high pressure over the entire surface, but as described in the prior art, the crystal resonator provided in the mold Since the positioning and fixing pins act effectively, there is no problem with respect to the positional deviation of the crystal unit.

  However, since the resin injected at a high injection pressure flows in as shown by an arrow in FIG. 5 and covers the crystal resonator 2, the crystal resonator 2 receives pressure on the entire surface thereof. Therefore, depending on the case, a part of the crystal unit 2 may be deformed.

  In particular, the sealing tube 2a of the quartz crystal resonator 2 is formed by deep drawing a thin metal plate, and since the top surface portion is a flat surface, the flat surface easily receives high pressure. For this reason, the top surface portion is a portion most likely to be deformed. Since the top surface portion is pressed from the outside by the resin that has passed through the gaps in the molds 4 and 5, there is a possibility that the top surface portion is indented and deformed inside the sealing tube 2a as indicated by a broken line in FIG. . When such a deformation occurs, the top surface portion comes into contact with a crystal piece housed inside the crystal resonator 2, resulting in a product defect.

  Since the sealing tube 2a is cylindrical, the outer peripheral surface portion is a curved surface, so that the received pressure is dispersed and does not deform. Further, the lead terminal 2b side is not deformed because it is a bottom portion of an airtight terminal (not shown) press-fitted into the sealing tube 2a.

  In order to avoid the above-mentioned deformation problem, it is conceivable to inject the resin by slightly lowering the injection pressure. However, in this case, the wraparound of the resin is worsened and a weld is generated in a portion where the resin thickness is thin. It is difficult to adopt because of the problem.

  In view of the above problems, the present invention intends to provide a surface-mount type crystal resonator that is satisfactorily resin-molded without deforming a sealing tube constituting the crystal resonator.

At least a cylinder-type crystal unit,
A lead frame that supports the cylinder-type crystal resonator and is connected to a terminal of the cylinder-type crystal resonator to form an external connection terminal;
In the surface mount type crystal resonator in which the cylinder type crystal resonator is resin molded by injection molding,
The entire surface of the top surface of the sealing tube, which is the outer periphery of the cylinder-type crystal resonator, has a convex shape facing outward, and is a surface-mount crystal resonator that is not a flat surface.

  A surface-mount type crystal resonator in which the top surface portion of the sealing tube has a spherical shape is used.

  A surface-mount type crystal resonator in which a top surface portion of the sealing tube has a conical shape is used.

  According to the present invention, since the top surface portion of the sealing tube of the crystal resonator that is easily deformed by the injection pressure of the resin injected at the time of injection molding is formed in a convex shape and is not a flat surface, the pressure applied to the top surface portion Can be dispersed, and a good surface-mount type crystal resonator that prevents deformation can be obtained.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol shall be used about the same member as what was shown to the prior art.

  1A and 1B are views showing a surface-mounted crystal resonator according to an embodiment of the present invention, in which FIG. 1A is a front view and FIG. 1B is a top view. The two-dot chain line in the figure indicates the outer shape of the crystal resonator in the resin mold.

  Reference numeral 7 denotes a cylinder type crystal resonator (hereinafter simply referred to as a crystal resonator), in which a sealing tube 7a and a lead terminal 7b led out from one end thereof are fixed to the lead frame 3 by means such as welding. The crystal resonator 7 fixedly held on the lead frame 3 is sandwiched between injection molds arranged in the vertical direction, and a surface-mounted crystal resonator 10 is formed by injecting and solidifying resin into the mold. Since the injection molding means and the mold to be used are the same as those of the prior art, detailed description thereof is omitted.

  After the resin molding, a part of the lead frame 3 protruding to the outside is bent along the outer shape of the surface-mounted crystal resonator to become an external connection terminal 3a.

  The top surface portion of the sealing tube 7a has a convex portion 7c facing the outside of the sealing tube 7a, and has a shape that is not a flat surface. In the present embodiment, the convex portion 7c is formed in a spherical shape. According to this configuration, the pressure applied to the top surface portion by the injection pressure of the resin injected during injection molding can be dispersed, and deformation of the top surface portion can be prevented. Therefore, a good surface-mount type crystal resonator can be obtained.

  Since the sealing tube 7a is formed by drawing a metal thin plate, if the shape of the press machine is an arbitrary shape, a desired shape, in this embodiment, the top surface portion is a spherical shape. The sealing tube 7a can be easily formed.

FIG. 2 is a top view showing a surface-mounted crystal resonator according to another embodiment of the present invention. The two-dot chain line in the figure indicates the outer shape of the crystal resonator in the resin mold.
Reference numeral 8 denotes a cylinder-type crystal resonator (hereinafter simply referred to as a crystal resonator), which has a sealing tube 8a and lead terminals 8b led out from one end side thereof. The crystal resonator 8 is sandwiched between injection molds arranged in the vertical direction, and a surface-mounted crystal resonator 11 is formed by injecting and solidifying resin into the mold. Since the injection molding means and the mold to be used are the same as those of the prior art, detailed description thereof is omitted.

  The top surface portion of the sealing tube 8a has a configuration having a convex portion 8c facing the outside of the sealing tube 8a, and has a shape that is not a flat surface. In the present embodiment, the convex portion 8c is formed in a conical shape. According to this configuration, the pressure applied to the top surface portion by the injection pressure of the resin injected during injection molding can be dispersed, and deformation of the top surface portion can be prevented. Therefore, a good surface-mount type crystal resonator can be obtained.

  The sealing tube 8a is formed by drawing a metal thin plate in the same manner as in the first embodiment, and a sealing tube 8a having a conical top surface as in this embodiment can be easily formed. .

  As explained above, since the top surface of the sealing tube of the crystal resonator that is easily deformed by the injection pressure of the resin injected during injection molding is formed in a convex shape and is not a flat surface, the pressure applied to the top surface Thus, it is possible to obtain a good surface-mount type crystal resonator in which deformation is prevented. The shape of the top surface of the sealing tube is not limited to the spherical shape or the conical shape shown as a specific example, and it is needless to say that the shape can be implemented in various forms without departing from the gist of the present invention.

The figure which shows the surface mount-type crystal resonator of one Example of this invention. Example 1 The top view which shows the surface mount-type crystal resonator of the other Example of this invention. (Example 2) The perspective view of the surface mount type crystal unit manufactured by the prior art. FIG. 4 is a diagram of the surface-mounted crystal resonator of FIG. 3 viewed from three directions. FIG. 6 is a front cross-sectional view showing the positional relationship between the mold and the crystal unit during the manufacturing process of the surface mount type crystal unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Surface mount type crystal resonator 2 Crystal resonator 2a Sealing tube 2b Lead terminal 3 Lead frame 3a External connection terminal 4 Upper die 4a Pin 4a 'hole 5 Lower die 6 Gate port 7 Crystal resonator 7a Sealing tube 7b Lead terminal 7c Convex part 8 Quartz crystal 8a Seal tube 8b Lead terminal 8c Convex part

Claims (3)

At least a cylinder-type crystal unit,
A lead frame that supports the cylinder-type crystal resonator and is connected to a terminal of the cylinder-type crystal resonator to form an external connection terminal;
In the surface mount type crystal resonator in which the cylinder type crystal resonator is resin molded by injection molding,
A surface-mounted crystal resonator, wherein the entire top surface of the sealing tube, which is an outer peripheral portion of the cylinder-type crystal resonator, has a convex shape facing outward and is not a flat surface.   The surface-mount type crystal resonator according to claim 1, wherein a top surface portion of the sealing tube has a spherical shape. The surface-mount type crystal resonator according to claim 1, wherein a top surface portion of the sealing tube has a conical shape.

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