Horology: time measuring systems or devices – Electrical time base – Solid state oscillating circuit type
Reexamination Certificate
2000-08-11
2001-12-04
Miska, Vit (Department: 2859)
Horology: time measuring systems or devices
Electrical time base
Solid state oscillating circuit type
C368S204000, C318S696000
Reexamination Certificate
active
06327225
ABSTRACT:
TECHNICAL FIELD
The present invention relates to electronic units having a plurality of motors and to control methods for electronic units.
BACKGROUND ART
Recently, there have been known compact analog timepieces, such as watches, provided with only one motor and a hand moving mechanism for simultaneously moving a seconds hand, a minute hand, and an hour hand according to the driving timing of the motor and those provided with a plurality of motors so that a seconds hand and minute and hour hands, or a seconds hand, a minute hand, and an hour hand are separately driven according to the driving timings of the motors.
Analog timepieces which drive three hands by one motor are inferior in terms of flexibility in driving control to analog timepieces which drive hands by a plurality of motors because they have to drive all the three hands by one motor.
When a seconds-hand moving mechanism and an hour-and-minute-hand moving mechanism are independently driven by two motors, hand-moving timings match the driving timings of the motors. Therefore, if the seconds-hand and the hour-and-minute-hand moving timings are the same, a seconds motor and an hour-and-minute motor are driven at the same time. A current load for driving the motors occur at that time and a problem arises in that a power-supply voltage is reduced.
To prevent the power-supply voltage from decreasing, it can be considered that different intervals are used for the driving timings of the seconds motor and the hour-and-minute motor. In this case, a problem occurs in that a difference between the hand-moving timings for the seconds hand and the hour and minute hands becomes conspicuous to the user.
The above-discussed problems will be specifically described below.
FIG. 11
shows the structure of a general driving control system in a time measuring apparatus, which is a prerequisite for the following description.
As shown in
FIG. 11
, a driving control circuit
24
generates a driving-pulse control signal, and sends the generated driving-pulse control signal to an hour-and-minute driving circuit
30
m
and to a seconds driving circuit
30
s
. The hour-and-minute driving circuit
30
m
and the seconds driving circuit
30
s
send an hour-and-minute driving-pulse signal to an hour-and-minute motor
10
m
and a seconds driving-pulse signal to a seconds motor
10
s
, respectively, according to the driving-pulse control signal sent from the driving control circuit
24
.
The hour-and-minute motor
10
m
and the seconds motor
10
s
drive the hour-and-minute motor
10
m
and the seconds motor
10
s
to move hands by the hour-and-minute driving-pulse signal and the seconds driving-pulse signal sent from the hour-and-minute driving circuit
30
m
and the seconds driving circuit
30
s
, respectively.
The driving control circuit
24
is also provided with a function for detecting the rotations of the hour-and-minute motor
10
m
and the seconds motor
10
s
according to induced voltages generated at driving coils not shown by the rotations of the motors, and a function for detecting magnetic fields around the hour-and-minute motor
10
m
and the seconds motor
10
s
according to induced voltages generated at the driving coils not shown by the surrounding magnetic fields.
The driving control circuit
24
determines with the use of the above-described rotation detection function whether the hour-and-minute motor
10
m
and the seconds motor
10
s
correctly rotate by the hour-and-minute driving-pulse signal, and also determines with the use of the magnetic-field detection function whether an external magnetic field which affects the normal functioning of the rotation detection function exists around the hour-and-minute motor
10
m
and the seconds motor
10
s.
A detailed description will be given by referring to FIG.
10
.
When the seconds hand and the hour and minute hands are driven by the motors in that order, for example, the driving control circuit
24
outputs the seconds driving-pulse signal K
1
s
6
to the seconds driving circuit
30
s
to drive the seconds hand as shown by the pulse timing O
s
6
in FIG.
10
.
After outputting the seconds driving-pulse signal K
1
s
6
, the driving control circuit
24
outputs a seconds rotation-detection-pulse signal SP
2
s
6
used for checking whether the seconds hand has correctly rotated.
If a correct rotation is not detected by the use of the seconds rotation-detection-pulse signal SP
2
s
6
, the driving control circuit
24
outputs a seconds auxiliary pulse signal P
2
s
6
used for positively driving the seconds hand, which is larger in effective electric power than the seconds driving-pulse signal K
1
s
6
, to drive the seconds motor
10
s.
As shown by the pulse timing O
m
6
in
FIG. 10
, the driving control circuit
24
outputs an hour-and-minute driving-pulse signal K
1
m
6
to the hour-and-minute driving circuit
30
m
to drive the hour and minute hands.
The period of time T
61
shown in
FIG. 10
indicates the maximum period between the seconds-hand moving timing and the hour-and-minute-hand moving timing. If the period of time T
61
is long, the difference between the seconds-hand moving timing and the hour-and-minute-hand moving timing becomes conspicuous to the user.
The period of time T
62
shown in
FIG. 10
indicates the minimum period between the seconds-hand moving timing and the hour-and-minute-hand moving timing. If the period of time T
62
is short and current loads caused by the driving of the hour-and-minute motor
10
m
and the seconds motor
10
s
, which drive the hour and minute hands and the seconds hand, overlap, the power-supply voltage is reduced and in some cases, incorrect hand movement may be performed.
When the seconds hand and the hour and minute hands are driven with the period of time T
61
being set such that the difference between the seconds-hand moving timing and the hour-and-minute-hand moving timing does not become conspicuous to the user, it is understood from the above description that the period T
62
becomes too short and a problem arises in that the hour-and-minute driving-pulse signal K
1
m
6
is output before the power-supply voltage has recovered from a reduced voltage caused by the output of the seconds auxiliary pulse signal P
2
s
6
after the seconds auxiliary pulse signal P
2
s
6
has been output.
OBJECT OF INVENTION
The present invention has been made in consideration of the above situation.
Accordingly, an object of the present invention is to provide an electronic unit and a control method for an electronic unit which suppress a reduction in power-supply voltage even if a plurality of motors are driven, and which allow a difference in hand moving timing to be made inconspicuous.
DISCLOSURE OF INVENTION
In a first mode of the present invention, an electronic gear for driving a plurality of motors by the use of electric power supplied from a power supply is characterized by comprising a magnetic-field detection unit for detecting an external magnetic field around the motors; a rotation detection unit for detecting the rotations of the motors; an output-timing control unit for controlling the output timings of driving pulses for driving the motors, according to at least one of the detection results obtained by the magnetic-field detection unit and the rotation detection unit, and for controlling such that, in a state in which a power-supply voltage is recovered from a reduced voltage caused by the output of a first driving-pulse signal for driving a first motor, which is one of the motors, a seconds driving-pulse signal for driving a seconds motor, which is another motor, is output within a predetermined period of time, determined in advance, after the output of the first driving-pulse signal; and a driving-pulse output unit for outputting the driving-pulse signals to the motors under the control of the output-timing control unit.
A second mode of the present invention is characterized in that, in the first mode, the output-timing control unit is provided with an auxiliary-driving-pulse-signal output control unit for controlling such that
Kitahara Joji
Kojima Hiroyuki
Okeya Makoto
Shimura Noriaki
Yabe Hiroshi
Gabrik Michael T.
Miska Vit
Seiko Epson Corporation
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