JP2009088805A - Surface-mounted type crystal vibrator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-mounted type crystal vibrator which is improved in moldability of a resin mold and durability of the resin. <P>SOLUTION: A sealing tube 2a of a cylinder type crystal vibrator 2 is supported by a lead frame 3 and a terminal 2b of the cylinder type crystal vibrator 2 is connected to the lead frame 3. A portion of the lead frame 3 fitted with the cylinder type crystal vibrator 2 is clamped with an upper mold 7 and a lower mold 8 of an injection molding device and after the sealing tube 2a of the cylinder type crystal vibrator 2 is positioned and fixed with a crystal oscillator fixing pin 5 provided to the upper mold 7, a resin 4 is charged from a gate opening 9 of the metal mold to mold the cylinder type crystal vibrator 2 and lead frame 3 with the resin. At this time, the crystal vibrator fixing pin 5 is disposed on the sealing tube 2a of the cylinder type crystal vibrator 2 while avoiding a thin portion of resin molding, so there is no obstacle to a flow of the resin 4 of the thin portion to prevent or make small the welding at the thin portion. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a surface-mounted crystal resonator in which a cylinder-type crystal resonator is resin-molded.

  Various forms have been proposed as surface-mount crystal units.

  A surface-mounted crystal resonator in which a cylinder-type crystal resonator is resin-molded will be described with reference to the drawings. FIG. 4 is a cross-sectional view illustrating a resin molding process. FIG. 5 is a three-side view of a conventional surface-mount type crystal resonator.

  As shown in FIG. 4, the lead frame 3 to which the cylinder type crystal resonator 2 is attached is set in a mold of an injection molding apparatus. The terminal 2b of the cylinder type crystal resonator 2 is connected to the lead frame 3. The quartz crystal resonator fixing pin 5 provided in the mold of the injection molding apparatus positions and fixes the sealing tube 2a of the cylindrical crystal resonator 2 with a thin portion of the resin mold, and a part of the lead frame 3 (not shown) is fixed. It is sandwiched between the upper mold 7 and the lower mold 8 of the injection molding apparatus, and the resin 4 is filled from the gate port 9.

  In the short-side direction of the surface-mounted crystal resonator 1 in which the cylindrical cylinder-shaped crystal resonator 2 is resin-molded, the cylinder-shaped crystal resonator 2 is the thinned portion where the thickness of the resin 4 closest to the outer surface is the thinnest.

  As shown in FIG. 5, the surface-mounted crystal resonator 1 has a hole 6 formed by a crystal resonator fixing pin 5 in a thin portion on the upper surface, and an external terminal 3 a formed by a lead frame 3 on the side surface and the lower surface. The cylindrical crystal resonator 2 is housed inside the resin 4.

JP-A-9-139648

  However, it has been found that a problem occurs when the quartz crystal resonator fixing pin is arranged in the thin wall portion of the resin mold. This will be described below with reference to FIGS. FIG. 6 is a top view for explaining a defective portion of a conventional surface-mount type crystal resonator.

  As shown in FIG. 4, resin is injected from the gate port 9. The resin flows from the periphery of the joint between the lead frame 3 and the terminal 2b of the cylindrical crystal resonator 2 to the periphery of the top surface of the sealing tube covering the sealing tube 2a. At this time, the two quartz crystal resonator fixing pins 5 provided in the thin wall portion impede the flow of the resin, and the resin is filled from the side toward the thin wall portion. Therefore, as shown in FIG. The weld 10 is formed between the holes 6-6 formed by the two crystal resonator fixing pins 5 arranged in the section.

  The weld 10 may have weak joint strength due to variations in injection molding conditions, and the resin may expand and contract due to rapid superheating and rapid cooling during reflow when mounted on a circuit board, causing cracks in the weld 10. At that time, some users may complain that there is a problem in appearance even if the characteristics as a crystal resonator are satisfied.

  It is an object of the present invention to provide a surface-mount type crystal resonator in which the moldability and durability of a resin mold are improved.

  And at least a cylinder-type crystal unit and a lead frame that supports the cylinder-type crystal unit and is connected to a terminal of the cylinder-type crystal unit to form an external terminal. The cylinder-type crystal unit and the lead In the surface-mount type crystal resonator in which the frame is resin-molded by an injection molding device, the crystal resonator fixing pin for positioning and fixing the cylinder-type crystal resonator provided in the mold of the injection molding device includes: A surface-mounted crystal resonator is formed by resin molding in a state where the resin thickness between the cylinder-type crystal resonator and the outer surface after the resin molding is avoided is avoided.

  Further, it is assumed that the crystal resonator fixing pin is a surface-mount type crystal resonator in which at least two places are arranged.

  By placing the crystal unit fixing pin while avoiding the thin part of the resin mold, the flow of the resin to the thin part during resin molding is improved, and the weld generated in the thin part can be eliminated or reduced. In addition, it is possible to provide a surface-mounted crystal resonator with improved durability against thermal stress.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a surface-mount type crystal resonator according to the present invention. FIG. 2 is a diagram for explaining a surface-mounted crystal resonator according to the present invention. FIG. 3 is a top view of another embodiment of the surface-mount type crystal resonator according to the present invention. Since the resin molding process is the same in the present invention and the prior art, the resin molding process will be described with reference to FIG.

  As shown in FIG. 4, the sealing tube 2 a of the cylinder type crystal resonator 2 is supported by the lead frame 3, and the terminal 2 b of the cylinder type crystal resonator 2 is connected to the lead frame 3.

  A part (not shown) of the lead frame 3 to which the cylinder type crystal unit 2 is attached is sandwiched between the upper mold 7 and the lower mold 8 of the injection molding apparatus, and the crystal unit fixed to the upper mold 7 is fixed. The sealing tube 2a of the cylinder type crystal resonator 2 is positioned and fixed with the pin 5.

  The resin 4 is filled from the gate 9 of the mold, and the cylinder type crystal unit 2 and the lead frame 3 are resin molded. At that time, since the quartz crystal resonator fixing pin 5 is arranged so as to avoid the thin portion of the resin mold with respect to the sealing tube 2a of the cylinder type crystal resonator 2, the flow of the resin 4 in the thin portion is obstructed. It is possible to prevent or reduce the occurrence of the weld 10 at the thin wall portion.

  Since the crystal resonator fixing pin 5 is provided so as to be diagonal with respect to the thin portion of the resin, the surface of the surface-mounted crystal resonator that has been molded is provided on the upper surface of the crystal resonator fixing pin 5 as shown in FIG. Holes 6 that are marks are formed diagonally to the thin-walled portion of the resin.

  As shown in FIGS. 1 and 2, the weld 10 is not generated on the upper surface of the surface-mounted crystal resonator 1 or is extremely small even if it is generated. Further, one end of the lead frame 3 connected to the terminal 2 b of the cylinder type crystal resonator 2 becomes an external terminal 3 a of the surface mount type crystal resonator 1.

  Incidentally, the holes 6 formed on the upper surface of the surface-mount type crystal resonator 1 are not limited to being formed diagonally as shown in FIG. 2, but as shown in FIG. Two or more locations may be formed at positions avoiding the thin portion.

A perspective view of a surface-mounted crystal resonator according to the present invention. The figure explaining the surface mount type crystal unit by this invention FIG. 6 is a top view of another embodiment of the surface-mounted crystal resonator according to the present invention. Sectional drawing explaining resin molding process Three views of a conventional surface-mount crystal unit Top view explaining the defects of a conventional surface-mount crystal unit

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Surface mount type crystal resonator 2 Cylinder type crystal resonator 2a Sealing tube 2b Terminal 3 Lead frame 3a External terminal 4 Resin 5 Crystal resonator fixing pin 6 Hole 7 Upper die 8 Lower die 9 Gate port 10 Weld

Claims (2)

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 terminal;
In the surface mount type crystal resonator in which the cylinder type crystal resonator and the lead frame are resin-molded by an injection molding device,
The crystal resonator fixing pin for positioning and fixing the cylinder-type crystal resonator provided in the mold of the injection molding apparatus has the largest resin thickness between the cylinder-type crystal resonator and the outer surface after resin molding. A surface-mount type crystal resonator characterized by being resin-molded in a state where it is disposed at a position avoiding a thinned portion.   2. The surface-mounted crystal resonator according to claim 1, wherein at least two crystal resonator fixing pins are arranged.

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