Oscillators – Solid state active element oscillator – Transistors
Reexamination Certificate
1999-11-30
2001-06-26
Mis, David (Department: 2817)
Oscillators
Solid state active element oscillator
Transistors
C331S077000, C331S096000, C331S10800D, C331S1170FE, C331S179000, C455S129000
Reexamination Certificate
active
06252470
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a microwave oscillating circuit used in a remote controller of home appliance products such as “kotatsu” adjustable by a remote controller using a radio wave.
BACKGROUND OF THE INVENTION
A remote controller attached to home appliances adjustable with a radio wave from a remote controller employs a microwave in order to avoid interference with unwanted electromagnetic wave emitted from various other home appliances, because the frequency of microwave is substantially apart from those of the electromagnetic waves. A microwave oscillating circuit mounted to a remote controller employs a strip-line stub of which tip is open. The strip-line stub is formed by a printed circuit board including a dielectric layer having a uniform dielectric constant and being subject to little loss in order to stabilize oscillating characteristics such as an oscillating frequency, oscillating output power and the like. A “kotatsu” is one of those home appliances adjustable with a microwave from a remote controller. A “kotatsu” is a Japanese traditional heating appliance used mostly in a living room. The constitution of “kotatsu” is explained in general in Prior Art of U.S. Pat. No. 4,449,034.
In the kotatsu, a remote controller is integrated into a top plate of the kotatsu and transmits a weak microwave signal modulated by a control signal to a receiver. The receiver integrated into a kotatsu body receives and demodulates the microwave signal, and the resultant signal controls a temperature of heating element of the kotatsu. Disperses of components characteristics transistors' characteristics among others making up the microwave oscillating circuit cause a disperse of an oscillating frequency. Since a control sensitivity of respective remote controllers is subject to the disperse, each product eventually has its own dispersion. In order to suppress this dispersion of the oscillating frequency, a bandwidth of a band-pass-filter in the receiver has been widened; however, the resultant receiver has been vulnerable to noises and unwanted electromagnetic waves. This method is, therefore, not appropriate to overcome the problem. Other methods described below have been employed to overcome the problem discussed above.
(1) Variable inductance
82
A is added to an oscillating circuit as shown in
FIG. 8A
; however, this not only enlarges a size of a remote controller but also boosts the cost.
(2) Japanese Patent Application Non-examined Publication No. H05-335833 discloses that conductive small lands
85
A-
85
E powered in advance are disposed in resonator
85
, one of elements making up an oscillating circuit, as shown in FIG.
8
B. The small lands are physically separated from resonator
85
by a laser cutter thereby varying an electrical length of resonator
85
so that an oscillating frequency can be adjusted. This method, however, requires an expensive precision apparatus such as a laser cutter.
(3) Japanese Patent Application Non-examined Publication No. H09-162642 discloses that tip-open type stubs
88
A are provided in resonator
88
and conductive patterns
88
B are disposed near resonator
88
in advance, where resonator
88
is coupled to strip-line stub
87
which connected to circuit
86
as shown in FIG.
8
C. Those elements are electrically connected with solder or bonding wires thereby adjusting an oscillating frequency. This method, however, results in lowering reliability of the oscillating circuit because it requires solder bridges. Further, this method needs an expensive precision apparatus such as a wire-bonder.
SUMMARY OF THE INVENTION
The present invention addresses the problems discussed above and aims to provide a microwave oscillating circuit, which oscillates a frequency in a more stable manner than a conventional circuit, for a remote controller. This microwave oscillating circuit thus narrows the dispersion of control sensitivity of the remote controller.
The microwave oscillating circuit of the present invention adjusts the oscillating frequency by changing a length of a tip-open type strip-line-stub coupled to a base terminal of a transistor an element of the circuit mounted on a printed circuit board. For this purpose, small conductive lands are formed in an isolated manner near the open tip, and then these lands are coupled electrically with the stub tip. Chip resistors, in particular those having a small resisting value, are used for this coupling.
The construction discussed above allows the microwave oscillating circuit to adjust an oscillating frequency thereby compensating a dispersion of electrical characteristics of the transistors. This solves the problems previously discussed. The present invention thus can provide a quality, reliable and small size remote controller at a low cost.
REFERENCES:
patent: 3796976 (1974-03-01), Heng et al.
patent: 3921056 (1975-11-01), Mahoney
patent: 4527130 (1985-07-01), Lütteke
patent: 4600906 (1986-07-01), Blight
patent: 4818956 (1989-04-01), Stajcer
patent: 4906956 (1990-03-01), Kakihana
patent: 5321374 (1994-06-01), Uwano
patent: 5805026 (1998-09-01), Kuroda et al.
patent: 5982244 (1999-11-01), Fujisaki
patent: 6043727 (2000-03-01), Warneke et al.
patent: 5-335833 (1993-12-01), None
patent: 06013808 (1994-01-01), None
patent: 09162642 (1997-06-01), None
Matsushita Electric - Industrial Co., Ltd.
Mis David
Ratner & Prestia
LandOfFree
Microwave oscillating circuit and remotely controllable... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Microwave oscillating circuit and remotely controllable..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Microwave oscillating circuit and remotely controllable... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2512449