JPH073694Y2 - Surface mount type crystal unit - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a surface mount type crystal unit that uses a vacuum-press-sealed cylinder type crystal unit.

[Conventional technology]

In recent years, demands for smaller and lighter electronic parts have increased, and surface mount type electronic parts have been increasing in order to further increase the mounting density of substrates. The same applies to crystal oscillators, and there is an increasing demand for smaller and lighter surface mount types. Many of the surface-mount type crystal units that meet the requirements for downsizing and weight saving use originally small and lightweight cylinder type crystal units with improved heat resistance. A conventional surface mount type crystal unit that uses a cylinder type crystal unit has an internal cylinder made of engineering plastic, as shown in Fig. 2, which aims at cost reduction as well as size and weight reduction. In many cases, a cylinder type crystal unit is housed in an outer case that has a space for forming, and the leads (3) are formed so that they can be soldered.

[Problems to be solved by the device]

The conventional surface mount type crystal unit shown in FIG.
Two parts, the cylinder type crystal unit with improved heat resistance and the outer case made of engineering plastic, and the man-hours, the cylinder type crystal unit is housed in the outer case and the leads are formed. Therefore, it is possible to reduce the cost as well as the size and weight.

Now, in addition to the two leads, the surface mount type crystal unit shown in Figs. 2a and 2b has a slit on the end of the outer case facing the lead in the length direction to form a cap end of the cylinder type crystal unit. The parts are used as soldering points. However, although the cut is certainly shown in FIG. 2b, the cap end of the cylinder type crystal unit of the cut part of the outer case which must be soldered when actually mounted on the board is the land pattern of the board. Since the outer case is lifted by the thickness of the outer case, soldering may not be performed when the amount of solder is small. Also, the second
In the surface mount type crystal unit shown in the figure, in order to securely solder to the cut part of the outer case, the land pattern of the board, which is the cut part of the outer case, should be coated with solder more than the thickness of the outer case, It turns out that it must be placed on the land pattern of the substrate. . However, when the surface mount type crystal resonator shown in FIG. 2 is automatically mounted on a substrate, the surface mount type crystal resonator may be displaced due to nozzle suction and vibration of the mounting board. When the position shift occurs, the position shift can be corrected by the self-alignment effect in the general surface mount type electronic component, but in the case of the surface mount type crystal unit shown in FIG. 2, the lead ( 3) Soldering with only two leads to a small soldering area, so self-alignment effect cannot be expected, and in the end, it is not possible to solder at the cut part and the lead is misaligned. Only two leads (3) Will be soldered. If the soldering is not done securely at the cut portion, the end of the surface mount type crystal unit shown in FIG. 2 to be soldered is only the lead (3). If some force is applied to the part, the surface mount type crystal unit may start up or bend left or right with the soldered lead part as a fulcrum. And, especially when it got up, it turned out that it would not lie on the substrate unless the end of the surface mount type crystal unit was pressed in some way.

Therefore, considering a surface mount type crystal unit that can reliably solder at three points, if a metal piece is attached to the end in the length direction opposite to the lead, two pieces of the lead (3) and a metal piece are attached. It can be reliably soldered at three places on one piece. For example, as shown in FIG. 3a, a method of attaching a metal cap (5) to the end portion in the lengthwise direction facing the lead, and a side face of the outer case in the lengthwise end facing the lead as shown in FIG. 3b. A method of making a soldering part by cutting the metal piece (4) and inserting the metal piece (4) into the bottom of the outer case
As shown in FIG. 3c, a cylinder type crystal unit in which a metal piece (4) is welded to the cap end (2) is housed in an outer case, and the welded metal piece is bent on the bottom surface of the outer case to form a soldered portion. Can be considered. However, in each of the above methods, in order to make a surface mount type crystal unit, an outer case made of engineering plastic, a cylinder type crystal unit, and a metal piece or a metal cap are required. Since the soldering portion is formed at the end portion in the length direction, the number of steps is increased, resulting in a costly surface mount type crystal unit.

An object of the present invention is to solve the above problems and eliminate the conventional defects in a surface mount type crystal unit using a cylinder type crystal unit. That is, it is an object of the present invention to provide a surface mount type crystal resonator at low cost, which enables reliable automatic mounting with only two parts, a cylinder type crystal resonator and an outer case made of engineering plastic.

[Means for Solving the Problems]

In order to solve the above-mentioned problems, the tip of the cap part of the cylinder type crystal unit in which the cap is solder-plated into the outer case made of engineering plastic is inserted diagonally to the bottom of the outer case. The exposed outer peripheral portion of the cap tip may be used as a third soldering portion after the two leads.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a side view of a surface mount type crystal unit according to the present invention. The outer case (1) is made of engineering plastic such as PPS (polyphenylene sulfide) or liquid crystal polymer, and has an obliquely cylindrical space for accommodating a cylinder type crystal unit. The cylinder type crystal unit cap (2) with improved heat resistance is made of nickel silver and has a Pb surface.
It is covered with solder plating of about 40% (lead) and about 60% Sn (tin). Then, the cylinder type crystal unit is obliquely inserted into the outer case (1), the tip outer peripheral portion of the cap (2) of the cylinder type crystal unit is brought into contact with the bottom extension of the outer case (1), and the lead is attached. To form.

FIG. 4 is a sectional view of a surface mount type crystal unit according to the present invention mounted on a substrate. As is apparent from the figure, the leads (3) and the outer peripheral portion (2) of the tip of the cap of the cylinder type crystal unit are securely soldered to the land pattern (7) of the substrate. Fig. 5 a, b
Is an embodiment of exposing the end of the cap of the cylinder type crystal unit according to the present invention.

There are various types of cylinder type crystal units, such as AT-cut cylinder type crystal units, tuning fork type cylinder type crystal units, and the external shape is φ1mm × 4mm to φ3m.
Although the size is up to m × 10 mm, the present invention is effective in any case.

[Effect of device]

As described above, according to the present invention, in the surface mount type crystal unit using the vacuum press-fitted sealed cylinder type crystal unit, the cylinder type crystal unit is obliquely inserted into the outer case made of engineering plastic to solder. It was possible to use the outer peripheral portion of the cap end of the cylinder type crystal unit in which the attachment point was in contact with the extension of the bottom surface of the outer case. When the surface mount type crystal unit according to the present invention is placed on the substrate, the cap tip outer periphery of the cylinder type crystal unit will always contact the land pattern of the substrate. It became possible to reliably solder to the board at three points on the outer periphery of the tip of the cap. Since soldering can be reliably performed at three points, the surface mount type crystal unit does not rise or bend even when an external force is applied. In addition, the self-alignment effect can be surely expected as in general electronic parts, and it becomes possible to correct some misalignment of the surface-mount type crystal oscillator that occurs when mounting on a board. Further, in the surface mount type crystal resonator according to the present invention, since the soldering points other than the two leads are the tip of the cap of the cylinder type crystal resonator without relying on parts such as metal pieces, the conventional surface mount type crystal resonator As in the case of the child, the reliability of the board mounting could be improved without increasing the cost by only using the two parts, the cylinder type crystal unit and the outer case made of engineering plastic. Also, since the cap part of the cylinder type crystal unit is soldered, dropping the soldered land pattern to the ground reduces high frequency noise when the surface mount type crystal unit is oscillating. be able to.

From the above, yield at the time of component mounting and reliability of board mounting,
It can be said that there is a great effect in terms of noise reduction.

[Brief description of drawings]

FIG. 1 is a side view of a surface mount type crystal unit using a cylinder type crystal unit according to the present invention. Figure 2a
Is a side view of a surface mount type crystal unit that uses a conventional cylinder type crystal unit. FIG. 2B is a bottom view of a surface mount type crystal unit using a conventional cylinder type crystal unit. FIGS. 3A to 3C are examples of a surface mount type crystal unit in which a metal is used at the end portion in the length direction facing the lead and a soldering portion is formed in addition to the lead. FIG. 4 is a sectional view of a surface mount type crystal unit according to the present invention mounted on a substrate. 5a and 5b show an example of exposing the cap end of the cylinder type crystal unit according to the present invention. (1) …… External case made of engineering plastic (2) …… Cylinder type crystal unit cap (3) …… Cylinder type crystal unit lead (4) …… Metal piece (5) …… Metal cap ( 6) ... solder (7) ... board land pattern (8) ... board

Claims (1)

[Scope of utility model registration request] 1. A cylinder type crystal unit is obliquely housed in an outer case made of engineering plastic to expose the tip of the cap portion of the cylinder type crystal unit to the bottom surface of the outer case, and the exposed outer periphery of the cap end. A surface mount type crystal unit that can be soldered at a total of three places with two formed leads.