Electrical generator or motor structure – Non-dynamoelectric – Piezoelectric elements and devices
Reexamination Certificate
2002-11-27
2004-03-16
Dougherty, Thomas M. (Department: 2834)
Electrical generator or motor structure
Non-dynamoelectric
Piezoelectric elements and devices
Reexamination Certificate
active
06707234
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a quartz crystal unit, its manufacturing method and a quartz crystal oscillator.
In particular, the present invention relates to the quartz crystal unit and the quartz crystal oscillator comprising a width-extensional mode quartz crystal resonator with a new cut angle and new electrode construction which is available for wearable equipment, communication equipment, measurement apparatus and consumer products requiring miniaturization, high accuracy, shock-proof and low prices for the quartz crystal resonator.
BACKGROUND OF THE INVENTION
A NS-GT cut coupling quartz crystal resonator which vibrates in the coupled width-extensional mode and length-extensional mode is well known and used as a time standard of consumer products and communication equipment.
FIG. 9
a
and
FIG. 9
b
show a top view and a side view of the conventional NS-GT cut coupling quartz crystal resonator. In
FIGS. 9
a
,
9
b
, The resonator
200
comprises vibrational portion
201
, connecting portions
203
,
206
and supporting portions
204
,
207
. The supporting portions
204
and
207
include respective mounting portions
205
and
208
.
In addition, as shown in
FIG. 9
a
and
FIG. 9
b
, electrodes
202
and
211
are disposed on the upper and lower faces of the vibrational portion
201
, the electrode
202
extends to the mounting portion
205
through the connecting portion
203
, while the electrode
211
extends to the mounting portion
208
through the connecting portion
206
. The electrodes
202
and
211
have opposite electrical polarities, and two electrode terminals are constructed.
Also, as shown in
FIG. 10
, the resonator
200
is mounted on a pedestal
313
by conductive adhesives at the mounting portions
205
and
208
. Furthermore, the pedestal
313
is connected to two lead wires
314
,
315
which pass through a case
311
, and the pedestal
313
with the resonator
200
is housed in a quartz crystal unit of tubular type
300
comprising the case
311
and a cap
312
. Namely, the electrodes
202
and
211
are connected to the lead wires
314
and
315
, respectively.
Now, when an alternating current(AC) voltage is applied between both lead wires
314
and
315
, an electric field E
t
occurs alternately in the thickness T direction, as shown by arrow signs of the solid and broken lines in
FIG. 9
b
. As a result, the coupled width-extensional mode and the length-extensional mode whose frequencies are inversely proportional to width W and length L of the vibrational portion, respectively, can be excited at the same time, and the NS-GT cut coupling resonator coupled in inverse phase is provided. The above-mentioned resonator is formed integrally by a chemical etching process.
In addition, the lager the area of vibrational portion for the NS-GT cut resonator becomes (low frequency), the smaller series resistance R
1
becomes and the larger quality factor Q becomes. Also, the NS-GT cut resonator with excellent frequency temperature behavior is determined by a dimensional ratio W/L, and which has a value of 0.95 approximately. In order to get a frequency higher than 4 MHz, it is necessary to decrease the area of the vibrational portion for the resonator.
Recently, according to the miniaturization and weight lightness of consumer products and communication equipment with a frequency higher than 4 MHz, a miniature quartz crystal unit and a miniature quartz crystal oscillator comprising a NS-GT cut resonator with the higher frequency is also required with a small series resistance R
1
and high quality factor Q.
It is, however, impossible to provide a miniature quartz crystal unit and a miniature quartz crystal oscillator having a NS-GT cut resonator with a frequency higher than about 4 MHz with a small series resistance R
1
and a high quality factor Q because the area of vibrational portion for the resonator becomes very small to get the higher frequency, and more an electro-mechanical transformation efficiency becomes very small, so that a series resistance R
1
becomes large and a quality factor Q also becomes small.
It is, therefore, desirable to provide a quartz crystal unit and a quartz crystal oscillator comprising a novel and miniature quartz crystal resonator with a frequency higher than about 4 MHz with a small series resistance R
1
, a high quality factor Q and a zero temperature coefficient.
SUMMARY OF THE INVENTION
The present invention relates to a quartz crystal unit, its manufacturing method and a quartz crystal oscillator, In addition, the quartz crystal unit and the quartz crystal oscillator comprise a width-extensional mode quartz crystal resonator capable of vibrating in a single mode with a high electro-mechanical transformation efficiency and a zero temperature coefficient.
In particular, the present invention relates to the quartz crystal unit and the quartz crystal oscillator comprising the width-extensional mode quartz crystal resonator with a new cutting angle and new electrode construction.
It is an object of the present invention to provide a miniature quartz crystal unit comprising a width-extensional mode quartz crystal resonator with a high electro-mechanical transformation efficiency.
It is an another object of the present invention to provide a miniature quartz crystal unit comprising a width-extensional mode quartz crystal resonator with a frequency higher than about 4 MHz with a small series resistance R
1
and a high quality factor Q.
It is a further object of the present invention to provide a miniature quartz crystal unit comprising a width-extensional mode quartz crystal resonator with a zero temperature coefficient.
It is a still firer object of the present invention to provide a method of manufacturing a quartz crystal unit comprising a width-extensional mode quartz crystal resonator.
It is an another object of the present invention to provide a miniature quartz crystal oscillator comprising a width-extensional mode quartz crystal resonator with a high electro-mechanical transformation efficiency, a small series resistance R
1
, a high quality factor Q and a zero temperature coefficient.
In order to accomplish a miniature quartz crystal unit and a miniature quartz crystal oscillator comprising a width-extensional mode quartz crystal resonator with a frequency higher than about 4 MHz and a high electro-mechanical transformation efficiency by which a small series resistance R
1
and a high quality factor Q are provided, it is needed to provide a novel width-extensional mode quartz crystal resonator which is formed from a quartz crystal plate with a new cutting angle, new electrode construction and a large piezoelectric constant.
In accordance with the present invention, the quartz crystal unit and the quartz crystal oscillator are accomplished by a width-extensional mode quartz crystal resonator with a new cutting angle and having new electrode construction and a large piezoelectric constant.
In more detail, such a resonator is formed in accordance with the present invention, from a quartz crystal plate of a new cutting angle using a particle method.
Moreover, such a resonator is provided in accordance with the present invention, by new electrode construction and a large piezoelectric constant.
In addition, in accordance with the present invention, a width-extensional mode quartz crystal resonator with a zero temperature coefficient is accomplished by a cutting angle. As a result of which a quartz crystal unit and a quartz crystal oscillator of the present invention comprising the width-extensional mode quartz crystal resonator have good frequency temperature behavior over a wide temperature range, respectively.
REFERENCES:
patent: 4313071 (1982-01-01), Hermann et al.
patent: 4350918 (1982-09-01), Sato
patent: 4355257 (1982-10-01), Kawashima et al.
patent: 4900971 (1990-02-01), Kawashima
Proceedings of The 1992 IEEE Frequency Control Symposium, “New Cuts for Width-Extensional Mode Quartz Crystal Resonators”, H. Kawashima, May 27-29, 1992, pp. 525-531.
Proceedings of The 1993 IEEE Internatio
Adams & Wilks
Addison Karen Beth
Dougherty Thomas M.
Piedek Technical Laboratory
LandOfFree
Quartz crystal unit, its manufacturing method and quartz... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Quartz crystal unit, its manufacturing method and quartz..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Quartz crystal unit, its manufacturing method and quartz... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3250977