JP5148351B2 - Surface mount crystal unit - Google Patents

Description

  The present invention relates to a surface mount crystal resonator (hereinafter referred to as a surface mount resonator) as a technical field, and more particularly to a surface mount resonator that prevents a change in frequency due to directionality during mounting.

(Background of the Invention)
The crystal resonator is known as a frequency control and selection element, and is incorporated in an oscillation circuit, for example, to supply a stable oscillation frequency. One of these is a surface-mount vibrator using a ceramic container, which is mounted on a set substrate for various uses.

(Example of conventional technology)
FIG. 2 is a diagram of a surface-mounted vibrator for explaining a conventional example. FIG. 2 (a) is a sectional view, FIG. 2 (b) is a plan view excluding a cover, and FIG. 2 (c) is a bottom view.

  The surface-mount vibrator accommodates a crystal piece 2 in a concave ceramic container 1 having a bottom wall 1a and a frame wall 1b, and covers and covers a cover 3. The ceramic container 1 has a rectangular shape in plan view and has arc-shaped cutouts 8 at four corners. The first and second mounting terminals 4 (ab) are provided on the outer bottom surfaces on both end sides in the long side direction. The first and second mounting terminals 4 (ab) are electrically connected to first and second crystal holding terminals 5 (ab) on both sides of one end provided on the inner bottom surface of the ceramic container 1 (bottom wall 1a). .

  The first and second mounting terminals 4 (ab) and the first and second crystal holding terminals 5 (ab) are formed on the inner peripheral surface and the inner surface of the notch portion 6 provided on the outer surface of the short side center portion of the bottom wall 1a. The first and second wiring paths 7 (ab) on the bottom are connected. Each first wiring path 7a connects the first mounting terminal 4a and the first crystal holding terminal 5a on one end side. The second wiring path 7 (ab) is connected to the second mounting terminal 4b on the other end side and the second crystal holding terminal 5a on the one end side.

  In such a case, first, in the state of the sheet-like bottom wall 11a as an aggregate of the bottom wall 1a made of ceramic (see FIG. 3), the mounting terminal 4 (ab), the crystal holding terminal 5 (ab), and the wiring The path 7 (ab) is formed by printing such as W (tungsten). In this case, first, a through hole 16 that becomes the cutout portion 6 is formed in advance in the sheet-like bottom wall 11a, and W during printing flows into the through hole 16 to form an electrode through hole (through hole).

  Next, the sheet-like frame wall 11b is laminated on the sheet-like bottom wall 11a to form the sheet-like container 11, and the notches 8 are formed in the four corners of the ceramic container 1 where the dividing lines AA and BB intersect. Corresponding through holes 18 are provided. Next, Ni (nickel) and Au (gold) films are formed by electrolytic plating on W exposed on the surface of the sheet-like container 11 by, for example, electrolytic plating.

  Finally, the sheet-like container 11 is divided along a dividing line, and a semi-elliptical cutout 6 having a metal film that becomes a part of the wiring path 7 (ab) is formed on the inner peripheral surface. In this case, the through holes 16 provided at the intersections of the dividing lines prevent burrs from occurring at the four corners of the ceramic container 1 and facilitate the division. 2 and 3, the wiring pattern for electrolytic plating is omitted, and in FIG. 3, the wiring path 7 (ab) itself is also omitted for convenience.

  The crystal piece 2 has excitation electrodes 9 (ab) on both main surfaces, and the extraction electrodes 10 (ab) extend on both sides of one end portion which is an outer peripheral portion of the crystal piece 2. The extraction electrode 10 (ab) is formed, for example, by being folded back on each opposite surface. Then, both ends of one end of the crystal piece 2 from which the extraction electrode 10 (ab) extends are fixed to the first and second crystal holding terminals 5 (ab) by the conductive adhesive 12.

The cover 3 is made of ceramic, for example, and is sealed with glass at the opening end face of the ceramic container 1 so as to hermetically enclose the crystal piece 2. Such a surface-mounted vibrator is mounted on a set substrate (not shown) on which an IC or the like forming an oscillation circuit is arranged.
JP 2004-64701 A JP 2008-17092 A

(Problems of conventional technology)
However, the surface-mounted vibrator having the above configuration has the following problems when it is oscillated by being electrically connected to an oscillation circuit (FIG. 4) in an IC disposed on a set substrate, for example. That is, when the long-side direction of the surface-mounted oscillator is connected in reverse, that is, when the first and second mounting terminals 4 (ab) connected to the input / output terminals of the oscillation amplifier 13 are connected in reverse, the oscillation frequency There was a problem that changed. In FIG. 4, reference numeral 2A denotes a crystal resonator (surface mount resonator), Ca and Cb denote oscillation capacitors, and R denotes a feedback resistor.

In short, when the surface mount vibrator is mounted on the set substrate, the first and second wiring paths 7 (ab) generate stray capacitances C1 and C2 between the set substrate and the ground pattern. As shown in FIG. 4 , the stray capacitances C1 and C2 are added between both terminals of the crystal resonator 2A in the oscillation circuit and the ground. Here, since the second wiring path 7 (ab) is longer than the first wiring path 7 (ab), the stray capacitance C2 is larger than C1.

  Usually, the output capacitance of the oscillation amplifying element 13 of the oscillation circuit, for example, the inverter element is large and the input capacitance is small. Therefore, even if the stray capacitance C2 is added to the output side of the inverter element, the oscillation frequency is hardly affected, and the stray capacitance C1 on the input capacitance side affects the oscillation frequency. For this reason, if the direction of the long side direction of the surface-mounted vibrator is ignored and connected, the stray capacitance on the input side becomes C1 or C2, so that the frequency changes. In particular, a change in oscillation frequency becomes a problem when the stray capacitance C2 has a large capacitance.

(Object of invention)
An object of the present invention is to provide a surface-mount resonator that prevents a change in oscillation frequency and obtains a uniform oscillation frequency.

  The present invention has the first and second mounting terminals on the outer bottom surface at both ends in the long side direction as shown in the claims (Claim 1). The terminal has a rectangular rectangular shape in a plan view electrically connected to the first and second crystal holding terminals on the inner bottom surface by the first and second wiring paths, and the lead electrode is connected to the outer periphery from the excitation electrodes on both main surfaces. A crystal piece for surface mounting, in which the outer peripheral portion of the crystal piece from which the extraction electrode extends is electrically connected and fixed to the first and second crystal holding terminals. In the child, the first and second mounting terminals are configured to be asymmetrical with respect to a center line that bisects the long side direction of the ceramic container.

  With such a configuration, since the first and second mounting terminals are asymmetric, the directionality in the long side direction can be recognized. Therefore, it can always be mounted in the same direction on the set substrate on which the oscillation circuit is formed. In this case, the change in the oscillation frequency can be reduced by connecting the first or second mounting terminal having the larger stray capacitance between the crystal resonator and the ground as the output side of the oscillation amplifying element.

(Embodiment section)
According to a second aspect of the present invention, in the first aspect, the extended outer peripheral portion of the extraction electrode is fixed to the first and second crystal holding terminals as both ends of one end portion of the crystal piece, and the first and second The lengths of the two wiring paths are different. As a result, when the surface-mounted resonator is mounted on the set substrate with the long side direction reversed, the stray capacitance between both terminals of the crystal resonator and the ground changes, so the effect of claim 1 is significant. Become.

  In the third aspect of the present invention, in the first aspect, the ceramic container has an arc-shaped cutout at the four corners, and the first and second mounting terminals are outer peripherals that are at both ends of the ceramic container 1. The first and second mounting terminals are each provided with a notch that is asymmetrical in at least one of the opposing inner peripheries of the first and second mounting terminals. Thereby, the first and second mounting terminals can be made asymmetrical while the sheet-like container is easily divided.

  FIG. 1 is a view of a surface-mounted vibrator for explaining an embodiment of the present invention. FIG. 1 (a) is a bottom view and FIG. 1 (b) is a plan view. In addition, the same number is attached | subjected to the same part as a prior art example, and the description is simplified or abbreviate | omitted.

  As described above, the surface-mount vibrator accommodates the crystal piece 2 in the concave ceramic container 1 having a rectangular shape in plan view and having the notches 8 at the four corners, and covers the glass-sealed cover 3 so as to be hermetically sealed. To do. The first and second mounting terminals 4 (ab) provided on the outer bottom surfaces on both end sides in the long side direction of the ceramic container 1 are the first and second crystal holding terminals 5 on both sides of one end portion provided on the inner bottom surface. (Ab) is electrically connected to the first and second wiring paths 7 (ab). Even in this case, the second wiring path 7b is longer than the first wiring path 7a (refer to FIG. 2 (b)).

  In this embodiment, the notch 14 is provided in the first mounting terminal 4 a at one end of the outer bottom surface of the ceramic container 1. The notch 14 is provided, for example, at one of both corners on the inner periphery facing the second mounting terminal 4b. Thus, the first and second mounting terminals 4 (ab) are asymmetric with respect to the center line that bisects the long side of the ceramic container 1. The notch 14 may be at both corners or the center, and may be any shape as long as it is asymmetric.

In this case, corresponding to one end portion of the outer bottom surface on which the first mounting terminal 4a is provided, the first and second crystal holding terminals 5 (ab) are provided on both sides of one end portion of the inner bottom surface of the ceramic container 1 as described above. ). Then, both sides of one end of the crystal piece 2 from which the extraction electrode 10 (ab) extends are fixed to the crystal holding terminal 5 (ab). Therefore, one end of the container body 1 provided with the notch 14 is the crystal holding terminal 5a side where the crystal piece 2 is held.

  In this case, both sides of one end of the crystal piece 2 are fixed to the crystal holding terminal 5 (ab), and the cover 3 is joined and hermetically sealed. And the frequency or serial number (hereinafter referred to as product display) are displayed. For example, it displays from the one end part of the container main body 1 in which the notch 14 was provided toward the other end side.

  With such a configuration, when the surface-mounted oscillator is mounted on the set substrate, the mounting terminal 4a held at one end of the crystal piece 2 is connected to the oscillation amplifier based on the notch 14 on the outer bottom surface or the product display of the cover. Thus, the mounting terminal 4b at the other end can be reliably mounted (connected) as the output side.

  In this case, at one end portion of the surface mount vibrator (ceramic container 1), the wiring path 7a between the crystal holding terminal 5a and the mounting terminal 4a is short and the stray capacitance C1 is also small. At the other end of the ceramic container 1, the wiring path 7b between the crystal holding terminal 5b and the mounting terminal 4b is long and the stray capacitance C2 is large. Absent. Therefore, the influence on the oscillation frequency can be reduced and the oscillation frequency can be made uniform.

  The product is displayed in one direction with respect to the cover 3 based on the notch 14 on the outer bottom surface. Therefore, for example, even if the product display may be unclear or confused with the left and right, the product display may be inspected based on the notch 14 when checking the product display, so that an inspection error can be prevented.

  In the above embodiment, the crystal piece holds both sides of the extended end portion of the extraction electrode 10 (ab). For example, even when the extraction electrode 10 (ab) extends to both end portions and holds the same portion, The second wiring path 7 (ab) is different, or for other reasons, the present invention can be applied to the case where the oscillation frequency is different when the directionality is reversed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a bottom view and FIG. 2B is a plan view of a surface-mounted vibrator for explaining an embodiment of the present invention. It is a figure of the surface mount vibrator | oscillator explaining a prior art example, the figure (a) is sectional drawing, the figure (b) is a top view except a cover, and the figure (c) is a bottom view. It is a partially expanded plan view of a sheet-like container for explaining a conventional example. It is a figure of the oscillation circuit explaining the problem of a prior art example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Ceramic container, 2 Crystal piece, 3 Cover, 4 Mounting terminal, 5 Crystal holding terminal, 6 Notch part, 7 Wiring path, 8, 14 Notch, 9 Excitation electrode, 10 Lead electrode, 11 Sheet-like container, 12 Conductivity Adhesive, 13 Oscillating amplifier, 15, 16 Through hole.

Claims (2)

In a manufacturing method of a crystal unit for mounting comprising a ceramic container and a cover for sealing and sealing a crystal piece in the ceramic container , the first mounting terminal and the second mounting terminal are connected to both ends of the outer bottom surface of the ceramic container. opposed to the side, and wherein the provided asymmetrical notches on at least one of the peripheral inner opposed first mounting terminal and the second mounting terminal, on the basis of the notch, the A method of manufacturing a surface-mount crystal resonator , characterized by displaying a product on a surface of a cover .

Notches on the arc are provided at the four corners of the ceramic container, and the first mounting terminal and the second mounting terminal have the notch at both outer corners on both ends of the ceramic container. A method for manufacturing a surface-mount crystal resonator according to claim 1.