Horology: time measuring systems or devices – Power supply details
Reexamination Certificate
1998-11-24
2002-10-01
Roskoski, Bernard (Department: 2859)
Horology: time measuring systems or devices
Power supply details
C361S204000
Reexamination Certificate
active
06459658
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electronic timepiece for storing energy generated by a thermoelectric element at a secondary battery and operated by generated power as well as energy of the secondary battery, particularly to effective use of generated power in accordance with power conservation and means for appealing situation of power generation or deficiency in the energy of the secondary battery to a user.
2. Description of the Prior Art
FIG. 2
shows a view of a structure of a thermoelectric element used in a conventional electronic timepiece having a thermoelectric element. A number of n-type semiconductors
203
and p-type semiconductors
204
are installed between a heat absorbing side substrate
202
and a heat radiating side substrate
201
. The n-type semiconductors
203
and the p-type semiconductors
204
are alternately and electrically connected in series by electrodes
205
installed at the heat absorbing side substrate
202
and the heat radiating side substrate
201
and both ends thereof are led out as leads
206
. A heat flow is flowed through the n-type semiconductors
203
and the p-type semiconductors
204
in parallel.
The heat absorbing side substrate
202
is thermally coupled with a rear lid of the electronic timepiece in touch with the user's arm the temperature of which is generally higher than air temperature. The heat radiating side substrate
201
is thermally coupled with a timepiece case radiating heat to the atmosphere. When a temperature difference is caused between the heat absorbing side substrate
202
and the heat radiating side substrate
201
, an electromotive force is generated by the Seebeck effect.
Next, an explanation will be given of a construction of the conventional electronic timepiece having the thermoelectric element in reference to a block diagram of FIG.
14
. Electromotive force of a thermoelectric element
101
having a structure shown by
FIG. 2
is transmitted to a booster circuit
302
, boosted by the booster circuit
302
and is stored in a storage mechanism
103
. Electric energy stored in the storage mechanism
103
is supplied as power source of a timepiece unit
110
. The timepiece unit
110
is constituted by an oscillation or oscillating circuit
105
using quartz having a frequency of 32 kHz or the like, a frequency dividing circuit
106
for dividing an oscillation signal thereof into a signal having a period of 1 Hz and so on, a display driving circuit
107
for driving a step motor for display in accordance with a divided output and a display unit
108
comprising a step motor, a wheel train and display hands.
According to the constitution of the conventional electronic timepiece having the thermoelectric element, when the thermoelectric element
101
generates electricity, power consumption of the timepiece unit
110
is supplied by energy from the thermoelectric element
101
and an extra amount thereof is stored in the storage mechanism
103
. Meanwhile, when the electromotive force is not provided from the thermoelectric element
101
, the storage mechanism
103
supplies power to the timepiece unit
110
, energy held by the storage mechanism
103
is reduced and voltage of the storage mechanism
103
is gradually lowered. At this occasion, in a range of voltage by which the timepiece can be operated, naturally, energy necessary for the operation is taken out from the storage mechanism
103
and further, even after a motor is stopped and the operation of the timepiece is stopped, a certain degree of current flows, energy from the storage mechanism
103
continues being discharged and the voltage continues lowering. Further, when the voltage of the storage mechanism
103
is dropped to a degree of about 0.6 V by which current is not flowed to the timepiece unit
110
, lowering of voltage is stopped and the voltage is substantially maintained.
According to the above-described conventional electronic timepiece having the thermoelectric element, when power generation of the thermoelectric element is stopped for a long period of time, the voltage of the storage mechanism is lowered to the degree of about 0.6 V and even when power generation of the thermoelectric element is restarted and starts to charge the storage mechanism, an extremely long time period is needed until the voltage reaches about 1.0 V by which the timepiece can be operated normally. Although a time period for voltage to reach 1.0 V is dependent on power generation capability and capacity of the charge mechanism, when the charge capacity is set to an amount for operating for six months, several days are required for voltage to reach 1.0 V.
When the timepiece is detached from the arm before voltage reaches about 1.0V which is voltage for operating the timepiece, the timepiece is immediately stopped without being able to utilize energy of the storage mechanism. That is, although in order to make the timepiece continue operating even when it is detached from the arm, power generation of the thermoelectric element needs to continue for several days, actually, the power generation is interrupted highly probably in the midst of power generation.
Further, there is a request for downsizing and thinning in an electronic timepiece and downsizing is also requested to a storage mechanism. Therefore, energy stored to the storage mechanism is reduced, a time period capable of maintaining operation of a timepiece circuit by energy of the storage mechanism is shortened and a probability of causing stoppage of the timepiece circuit becomes high. In order to reduce danger of stoppage of operation, power consumption of the timepiece circuit needs to reduce when a thermoelectric element does not generate electricity.
Further, it is preferable to inform stoppage of power generation to a user when the thermoelectric element stops generating electricity. Further, it is also preferable to inform a user that a remaining amount of energy of the storage mechanism is reduced. Further, it is preferable to carry out the display in a state in which power consumption is reduced more than in normal display.
SUMMARY OF THE INVENTION
As means for resolving the above-described problem, an electronic timepiece having a thermoelectric element according to the present invention is installed with a thermoelectric element, a storage mechanism for storing an electromotive force of the thermoelectric element or storing a power produced by boosting an output from the thermoelectric element by a booster circuit, an oscillating circuit, a frequency dividing circuit or a time information calculating circuit, a display driving circuit, a display unit and in addition thereto, a power monitoring circuit for monitoring a situation of at least either one of generated power and stored energy by measuring generated voltage or current of the thermoelectric element or output voltage or current of the booster circuit or voltage of the storage mechanism, and an operation stopping circuit or a display drive controlling circuit for controlling operation of the oscillating circuit or the frequency dividing circuit or the time information calculating circuit or the display driving circuit by a detected output of the power monitoring circuit. When the power monitoring circuit detects stoppage of power generation of the thermoelectric element or a deficiency in stored energy of the storage mechanism, in order to reduce power consumed in the electronic timepiece, operation of the oscillating circuit, the frequency dividing circuit or the time information calculating circuit or the display driving circuit is controlled by an ON/OFF control by the display drive controlling circuit or the operation stopping circuit.
Further, in the case of a timepiece in a so-to-speak analog display using motors, a wheel train and hands as a displayer, in a constitution having a motor for a hour hand and a minute hand and a motor for a second hand, when the power monitoring circuit detects lowering of at least either one of generated power and stored energy, the
Akase Tokuya
Fujita Susumu
Kurasawa Yoshimitsu
Miyazaki Joichi
Adams & Wilks
Roskoski Bernard
Seiko Instruments Inc.
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