Oscillators – With outer casing or housing
Reexamination Certificate
2001-07-12
2003-12-23
Pascal, Robert (Department: 2817)
Oscillators
With outer casing or housing
C331S066000, C331S10800D, C331S158000, C257S698000, C257S700000
Reexamination Certificate
active
06667664
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an oscillator which can make compact a temperature-compensated oscillator particularly used in the field of mobile communications by, e.g., a radio communication device or portable telephone, a manufacturing method therefor, and an oscillator.
BACKGROUND ART
Quartz oscillators each using, e.g., quartz crystal as a piezoelectric vibrator (piezoelectric component) are widely utilized in the field of data communications, information processing, and the like. Particularly, a potable terminal such as a portable telephone requires a frequency stability in a wide temperature range and a stability exceeding the obtained frequency to temperature characteristics.
Regarding this, a piezoelectric vibrator comprised of, e.g., quartz crystal, has temperature characteristics in that its frequency changes according to the ambient temperature. As an example of this, it is widely known that an AT-cut quartz vibrator has specific temperature characteristics in that the frequency varies largely in the high and low temperature sides with respect to a temperature near 25° C. where the difference from the center frequency is the smallest. Therefore, in order to obtain the required characteristics described above, a temperature compensation circuit is generally added to a quartz oscillator so that stable operation can be obtained.
One temperature-compensated oscillator added with such a temperature compensation circuit has a container structure in which, as shown in, e.g., Japanese Patent Laid-Open Nos. 8-204452 and 9-167918, a container accommodating an oscillation circuit and a container accommodating a piezoelectric vibrator such as a quartz vibrator are integrally formed on the upper and lower sides of a substrate. As shown in
FIG. 13
a
, an oscillator
1301
with this temperature compensation function has a container
1305
in which an accommodating portion
1305
a
for a piezoelectric vibrator
1302
and an accommodating portion
1305
b
for an electronic component
1303
constituting an oscillation circuit or the like are integrally formed in its upper and lower sides.
Although not shown, a predetermined circuit interconnection is formed on the bottom surface of the accommodating portion
1305
a
of the container
1305
, and the piezoelectric vibrator
1302
is fixed to a predetermined portion of this circuit interconnection with a conductive adhesive or the like. In addition, a lid
1306
a
hermetically seals the interior of the accommodating portion
1305
a.
A predetermined circuit interconnection (not shown) is formed also on the bottom surface of the accommodating portion
1305
b
of the container
1305
, and the electronic component
1303
is mounted at a predetermined portion of this circuit interconnection. A lid may be provided also to the accommodating portion
1305
b
of the electronic component
1303
in order to seal this region. Alternatively, a filler
1303
a
formed of a synthetic resin may fill the accommodating portion
1305
b
so that it covers and protects the electronic component
1303
. In a temperature compensation type quartz oscillator shown in Japanese Patent Laid-Open No. 9-167918, an electronic component adjusting hole is formed in the lid of a container for the electronic component. The electronic component can be adjusted after a quartz oscillator is assembled and completed as well.
Also, another temperature-compensated oscillator has a container structure in which a container on which a substrate having an oscillation circuit is mounted and a container accommodating a piezoelectric vibrator are stacked on each other. As shown in
FIG. 14
, in an oscillator
1321
with this temperature compensation function, a container
1322
accommodating a piezoelectric vibrator and a container
1324
mounted with an electronic component
1323
constituting an oscillation circuit or the like are stacked on each other. The container
1324
has a recess. A predetermined circuit interconnection is formed at the bottom of this recess, and the electronic component
1323
is mounted at a predetermined portion of this circuit interconnection. A terminal of the circuit interconnection extends onto a bank surrounding the recess of the container
1324
, so that it is electrically connected to the piezoelectric vibrator in the container
1322
.
A portable terminal such as a portable telephone as described above requires downsizing and cost reduction as well as the frequency stability in a wide temperature range. Regarding these requirements, since the temperature-compensated oscillator with the arrangement of
FIG. 13
needs a container for accommodating a piezoelectric vibrator and a container for accommodating an electronic component, it is difficult to downsize.
Since the temperature-compensated oscillator has an integral structure, if a trouble occurs in either one of the piezoelectric vibrator and electronic component, the entire temperature-compensated oscillator becomes defective. For this reason, even if no trouble occurs in the electronic component, since the piezoelectric vibrator is defective, the non-defective electronic component is treated as a defective one.
As shown in
FIG. 13
b
, conventionally, sometimes the filler
1303
a
charged to fix the electronic component
1303
is attracted to the inner wall of the accommodating portion
1305
b
so it cannot completely cover the electronic component
1303
. As described above, the conventional arrangement leads to a decrease in manufacturing yield and leads to an increase in product cost.
The present invention has been made to solve the above problems, and has as its object to downsize an oscillator to become smaller than a conventional one and to manufacture an oscillator at a lower cost than in the conventional case.
DISCLOSURE OF INVENTION
According to the present invention, in a container for an oscillation circuit which accommodates a piezoelectric vibrator, an oscillator comprises an electrode structure, that can be electrically connected, on the other surface of a multilayered substrate where a piezoelectric component is to be mounted, which opposes a side where the piezoelectric component is mounted, the electrode structure having a sufficient thickness.
According to the present invention, when the container for the oscillation circuit is mounted on another substrate through the electrode structure, a space is defined by the electrode structure between another substrate and the container for the oscillation circuit.
According to another embodiment of the present invention, in a container for an oscillator comprised of a piezoelectric vibrator and a plurality of semiconductor components, there is provided an oscillator in which the semiconductor components are mounted on the other surface of a multilayered substrate where the piezoelectric vibrator is to be mounted, which opposes a side where the piezoelectric component is mounted, a surface where the piezoelectric vibrator is mounted has a recessed structure, and the surface where the semiconductor components are mounted has an electrode structure that can be electrically connected to an external circuit mounting substrate when mounted thereon, the electrode structure having a thickness slightly larger than those of the semiconductor components.
According to the present invention, when the container for the oscillation circuit is mounted on another substrate through the electrode structure, the semiconductor component is placed in a space defined by the electrode structure between another substrate and the container for the oscillation circuit.
According to the present invention, in an oscillator comprised of a piezoelectric vibrator and a plurality of semiconductor components, the semiconductor components are mounted on the other surface of a multilayered substrate, where the piezoelectric vibrator is to be mounted, which opposes a side where the piezoelectric component is to be mounted, a surface where the piezoelectric vibrator is mounted has a recessed structure, and the surface where the semiconductor components ar
Akagawa Hiroaki
Kobayashi Hirokazu
Blakely & Sokoloff, Taylor & Zafman
Glenn Kimberly E
Kinseki Limited
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