JP2001119244A - Crystal oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crystal oscillator that is miniaturized by especially reducing a thickness dimension and making the crystal oscillator short. SOLUTION: In a crystal resonator which is made of laminated ceramic having a recess, has a divided step part at one end side, electrically and mechanically holds a one end side of a piece of quartz crystal on the upper surface of the divided step part and is formed by adhering an IC chip and a capacitor onto the bottom of the recess, the laminated ceramic consists of a flat plate- shaped bottom wall, and a 1st frame wall having cavities in one set of opposite sides and a 2nd frame wall forming the divided step part as width being narrower than that of the 1st frame wall. In one set of cavities provided in the 1st frame wall, one cavity is narrower than the other and the longitudinal direction of the capacitor is inserted into it, the cross direction of the capacitor is inserted in the other cavity, and the piece of quartz crystal is held on the upper surface of the 1st frame wall having the one cavity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crystal oscillator for surface mounting in the industrial technical field, and more particularly to a method of accommodating a crystal piece, an IC chip and a chip element in a container body using a laminated ceramic.

[0002]

2. Description of the Related Art Crystal oscillators are used as various frequency and time reference sources in various electronic devices including communication devices. In recent years, miniaturization has been promoted as typified by, for example, mobile phones, and further miniaturization has been demanded for the next generation.

(Example of Prior Art) FIGS. 3 and 4 are views for explaining a conventional example. FIG. 3 is a sectional view of a crystal oscillator.
FIG. 4 is a bottom view of the same. In the crystal oscillator, a crystal blank 2, an IC chip 3, and a capacitor 4 (ab) are housed in an H-shaped container body 1 having concave portions on upper and lower surfaces. The crystal blank 2 is housed in the recess on the upper surface side, and the metal cover 5 is joined by seam welding. Further, the IC chip 3 and the capacitor 4 (a
b) is accommodated in a concave portion on the lower surface side, and a resin as the protective material 9 is embedded. The container body 1 is made of a laminated ceramic, and a metal ring 6 is soldered to the upper surface. The crystal blank 2 is fixed at one end where a lead electrode extends from an excitation electrode (not shown) with a conductive adhesive 7.

As shown by a dotted frame in FIG. 5, the IC chip 3 integrates circuit elements constituting a main part of an oscillation circuit.
Then, it is fixed to the bottom wall by face-down bonding. In the figure, reference numeral 8 denotes an amplifier, C1 and C2 denote oscillation capacitors, C3 denotes a bypass capacitor between a power supply and ground, C4 denotes a coupling capacitor that sends a high-frequency output (oscillation output) to the next stage, and 2A denotes a crystal oscillator. , R are resistors, Vcc is a power supply, and Vo is an output.

[0005] The capacitor 4 (ab) is the bypass and coupling capacitors C3 and C4, and the IC chip 3
Are arranged in the recesses 10 (ab) of the frame wall provided on both sides of the frame so that the length direction coincides with the side. These capacitors 4 (ab) are compared with the oscillation capacitors C1 and C2,
Because of the large capacity (about 10,000 pF) and difficulty in integration, it is inevitably housed separately from the IC chip 3 and independently.

[0006]

[Problems to be Solved by the Invention]
However, the crystal oscillator having the above configuration has the following problem with further miniaturization, particularly with a reduction in height. That is, I
Since the C chip 3 is accommodated in the lower surface recess and the protective material 9 is embedded, the height of the recess is increased. Further, the IC chip 3 is face-down bonded to the bottom wall while the container body 1 is in an H shape. Therefore, the bottom wall of the container body 1 is bent at the time of bonding, so that a minimum thickness is required. For this reason, it has been difficult to reduce the overall height to, for example, 1 mm or less.

From this, it is conceivable to make the container body concave, hold one end of the crystal blank in the internal dividing step, house the capacitor in the recess, and fix the IC chip to the center of the bottom wall. (Not shown). But in this case,
If the long side of the capacitor is accommodated in the recess with the long side of the capacitor facing the side of the frame wall as in the prior art, the width of the recess needs to be increased, and there has been a problem that one end of the crystal blank cannot be held sufficiently. Also,
When the longitudinal direction of the capacitor is inserted into the recess in order to provide symmetry, there is a problem that the external dimensions become large and the standard cannot be satisfied.

(Object of the Invention) It is an object of the present invention to provide a crystal oscillator which is reduced in size by promoting a reduction in thickness by reducing the thickness dimension.

[0009]

Means for Solving the Problems The present invention provides a set of depressions 1 provided on a first frame wall 12a of a container body 1 having a concave shape.
0 (ab) indicates that one recess 10a is smaller in width than the other recess 10b and the longitudinal direction of the capacitor 4a is inserted, and the other recess 10b is inserted in the width direction of the capacitor 4b. And

[0010]

According to the present invention, since the width of one of the recesses 10a is reduced and the longitudinal direction of the capacitor 4a is inserted, one end of the crystal blank can be sufficiently held. Hereinafter, an embodiment of the present invention will be described.

[0011]

1 and 2 are views for explaining one embodiment of the present invention. FIG. 1 is a half sectional view of a crystal oscillator, and FIG. 2 is a plan view excluding a second frame wall. The same parts as those in the prior art are denoted by the same reference numerals, and description thereof will be simplified or omitted.
As described above, the crystal oscillator is formed by housing the crystal blank 2, the IC chip 3, and the capacitor 4 (ab) in the recess of the container body 1 made of a laminated ceramic, and bonding the cover 5 thereto. The container body 1 has a bottom wall 11 and first and second frame walls 12 (a
b). A recess 10 is formed at both ends of the first frame wall 12a.
(Ab), and the width of one dent 10a is changed to the other dent 1
0b. The second frame wall 12b is the first frame wall 12a
Is formed to be smaller than the width of the first frame wall 12a.

Then, for example, a bypass capacitor 4
a is inserted into one of the recesses 10a having a small width in the longitudinal direction. Further, the coupling capacitor 4b is inserted in the width direction into the other large recess 10b, and is fixed by a conductive adhesive (not shown). The IC chip 3 is connected to both capacitors 4 (a
b) It is eccentrically fixed from the center during the fixing. The crystal blank 2 is electrically and mechanically connected to and held by the conductive adhesive 7 on the upper surface of the first frame wall (divided step portion) of one of the depressions 10a.

With such a configuration, the crystal blank 2, the IC chip 3, and the capacitor 4 (ab) are accommodated in one recess, so that the thickness can be basically reduced. Since the width of one of the recesses 10a is reduced to form a stepped portion, one end of the crystal blank 2 can be sufficiently held. Also, the capacitor 4a is accommodated in one of the recesses 10a in the longitudinal direction,
The capacitor 4b is accommodated in the widthwise other recess 10b in the width direction. Therefore, although the symmetry is lacking, the IC chip 3 and the capacitor 4 (ab) can be accommodated in the concave portion and the standard size can be maintained.

[0014]

Others In the above embodiment, the capacitor 4 (ab) is used for bypassing and coupling. However, other capacitors that are difficult to integrate, such as a CR filter for reducing phase noise, may be used. However, in this case, the bypass capacitor 4a is externally provided. Further, the first frame wall 12a has a single layer, but may have two layers according to the thickness of the capacitor 4.

[0015]

According to the present invention, a crystal ceramic, an IC chip, and a capacitor are accommodated in one laminated ceramic recess, and one set of recesses in the first frame wall has one recess wider than the other recess. Since the capacitor 4 is inserted in the longitudinal direction and the capacitor is inserted in the other recess in the width direction, it is possible to provide a crystal oscillator which has a reduced thickness, promotes a reduction in height, and is downsized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a crystal oscillator illustrating one embodiment of the present invention.

FIG. 2 is a plan view for explaining an embodiment of the present invention, excluding a second frame wall.

FIG. 3 is a cross-sectional view of a crystal oscillator illustrating a conventional example.

FIG. 4 is a bottom view illustrating a conventional example.

FIG. 5 is a circuit diagram of a crystal oscillator illustrating a conventional example.

[Explanation of symbols]

1 container body, 2 crystal pieces, 3 IC chips, 4 capacitors, 5 covers, 6 metal rings, 7 conductive adhesives, 8 amplifiers, 9 protective materials, 10 dents, 11 bottom walls, 12 frame walls.

Claims (1)

[Claims] 1. A step made of a laminated ceramic having a concave portion on one end side, and one end of a crystal blank is electrically and mechanically held on an upper surface of the divided step portion, and an IC is mounted on a bottom surface of the concave portion.
In the quartz resonator having a chip and a capacitor fixedly attached, the laminated ceramic is divided into a first frame wall having a flat bottom wall and a pair of opposing sides having a recess, and a width smaller than the width of the first frame wall. A pair of depressions in the first frame wall, one of the depressions having a smaller width than the other depression and being inserted in the longitudinal direction of the capacitor, and being inserted into the other depression. Insert the width direction of the capacitor,
A crystal oscillator, wherein the crystal piece is held on an upper surface of the first frame wall having the one recess.