JPH1144783A - Electroluminsecent circuit for watch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep the lighting time constant and suppress power consumption with a small and simple structure. SOLUTION: This electroluminescent (EL) circuit for a watch is provided with a drive circuit 2 feeding electric power to an EL section 4 and a timer circuit 8. The timer circuit 8 is constituted of a power storage circuit 10 charged to the operating voltage when a switch 6 is turned on and a stop circuit 12 stopping the power feed from the drive circuit 2 to the EL section 4 to turn it off when the power storage circuit 10 is charged to the operating voltage. The timer circuit 8 has a simple structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an EL light-emitting circuit for illuminating a time display section of a timepiece and the like, and more particularly to an EL light-emitting circuit provided with a timer circuit for limiting the EL lighting time to a fixed time.

[0002]

2. Description of the Related Art As a conventional EL light-emitting timepiece, there has been one in which an EL light-emitting circuit is provided in a hand movement circuit of the timepiece. In this timepiece, the emission time of the EL is measured using a timing circuit or the like in a hand operation circuit, and the EL is emitted for a certain period of time.

[0003] There is also an EL light-emitting timepiece provided with an EL light-emitting circuit separated from a hand operation circuit. This timepiece is configured to emit light while a switch is turned on.

[0004]

Normally, since a high battery voltage is required for EL emission, the battery voltage drops rapidly during EL lighting. At this time, in the above-described conventional EL light-emitting timepiece in which the EL light-emitting circuit is provided in the hand movement circuit, a sudden drop in the battery voltage may interfere with the timekeeping circuit and the hand movement, leading to a decrease in accuracy. there were.

On the other hand, in a conventional timepiece in which the EL light emitting circuit is separated from the hand movement circuit, the above-described EL lighting does not cause a decrease in the timekeeping accuracy. Since it cannot be incorporated, it has a very simple function of turning on the EL only while the switch is being turned on. Therefore, the lighting time of the EL varies depending on the operation time of the switch, and the lighting time generally increases,
There is a problem that the battery is often consumed quickly.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to provide a timepiece EL light emitting circuit which is small and simple, and which can suppress the power consumption by keeping the lighting time constant.

[0007]

According to the present invention, there is provided a timepiece EL light emitting circuit, comprising: a drive circuit for supplying power to an EL light emitting portion in response to an ON operation of a switch to emit light. And a timer circuit for stopping the power supply from the drive circuit to the EL light-emitting unit when a predetermined time has elapsed from the ON operation of the switch.

The timer circuit in the timepiece EL light emitting circuit according to the present invention includes a power storage circuit that is charged to an operating voltage when the switch is turned on and a predetermined time elapses, and a power storage circuit that is charged to the operating voltage after a lapse of a predetermined time. Then, a stop circuit for applying a stop signal to the drive circuit to stop the power supply to the EL light-emitting unit.

In the timepiece EL light emitting circuit according to the present invention, when the switch is turned off, the switch is short-circuited to discharge the power storage circuit.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The timepiece EL light emitting circuit according to the present invention is provided with a timer circuit in addition to a drive circuit for supplying power to the EL light emitting section, and the EL lighting time is set to a predetermined time by the timer circuit. Has restricted. The timer circuit has a power storage circuit that is charged to an operating voltage for a certain period of time when a switch is turned on, and stops the power supply from the drive circuit to the EL light emitting unit when the power storage circuit is charged to the operating voltage and turns off the light. And a stop circuit. Since the timer circuit has a simple configuration as described above, it can be downsized. Further, even if the switch is continuously turned on, the EL is turned off after a certain period of time until the power storage circuit is charged to the operating voltage, so that power consumption can be minimized. Furthermore, since the power storage circuit is discharged through the switch that has been turned off, the lighting time can be kept constant even when the switch is continuously turned on.

[0011]

FIG. 1 is a circuit diagram showing a timepiece EL light emitting circuit according to an embodiment of the present invention. Reference numeral 2 denotes a drive circuit that applies an AC voltage to the EL light emitting unit 4 to turn on the EL light emitting unit 4.

Reference numeral 6 denotes a switch which is provided on the outer periphery of the watch case or the like and which includes an externally operable push button or the like.
The switch 6 is provided between one electrode of a battery serving as a DC power supply and the drive circuit 2, and connects the drive circuit 2 and the battery when turned on. Also, this switch 6
Is configured not only to disconnect the drive circuit 2 from the battery when turned off, but also to connect the circuit-side connection line to the other electrode of the battery to short-circuit. That is, as shown in FIG. 2, the switch 6 has an operation portion 6a, a switch plate 6b having a contact piece 6e that is bent when pressed by the operation portion 6a, and a switch plate 6b pressed by the operation portion 6a. Plate 6c with which the contact piece 6e contacts
a is not pressed, the contact piece 6 of the switch plate 6b
e with which the short-circuit switch plate 6d contacts. The switch plate 6b, the receiving plate 6c and the short-circuit switch plate 6d are fixed to a watch exterior or the like, and only the contact pieces 6e having the spring property of the switch plate 6b contact the receiving plate 6c and the short-circuit switch plate 6d, respectively. Are arranged as follows. Then, the switch plate 6b is connected to the circuit side,
The receiving plate 6c is connected to one electrode side of the battery, and the short-circuit switch plate 6d is connected to the other electrode side of the battery.

Reference numeral 8 denotes a timer circuit, which applies a stop signal composed of a voltage signal to the power storage circuit 10 connected to the battery via the switch 6 and the drive circuit 2 when the charged voltage becomes higher than the operating voltage. And a stop circuit 12 for stopping power supply. The storage circuit 10 includes a current limiting resistor 14 and a capacitor 16 connected to the battery via the resistor 14 and the switch 6. Further, the stop circuit 12 is provided with a resistor 1 for limiting current.
8 and 20, and a transistor 22 having a base connected to the capacitor 16 via the resistor 18, a collector connected to the switch 6 via the resistor 20, and an emitter connected to the other electrode of the battery. Have been. The stop circuit 12 is connected so that a stop signal is applied to the drive circuit 2 from the collector side of the transistor 22.

Next, the operation of the watch EL light-emitting circuit having the above configuration will be described. First, when the switch 6 is pressed and turned on, the drive circuit 2 is connected between the electrodes of the battery via the switch 6, and an AC voltage is applied from the drive circuit 2 to the EL light emitting unit 4, and the EL light emitting unit 4 is turned on. Light.

At this time, the power storage circuit 10 is also connected between the electrodes of the battery via the switch 6, and the capacitor 16 is charged with a set time constant. Then, when the capacitor 16 is charged to the operating voltage or more after a certain period of time,
The transistor 22 having the charging voltage of the capacitor 16 as the base voltage is turned on. When the transistor 22 is turned on, a stop signal composed of a voltage signal is applied from the collector side to the drive circuit 2, and the drive circuit 2 stops applying the AC voltage to the EL light emitting unit 4 in response to the stop signal.

In this state, when the switch 6 is stopped and turned off, the switch 6 is connected to the ground electrode of the battery. As a result, the capacitor 16 discharges through the switch 6 and returns to the initial state. Therefore, even if the switch 6 is again turned on immediately after that, the time until the charged voltage reaches the operating voltage is always constant because the capacitor 16 has already returned to the initial state. By connecting the capacitor 16 and the off-side terminal of the switch 6 in FIG. 1 without the interposition of the resistor 14, the discharging time of the capacitor 16 at the time of the OFF operation can be shortened. However, it is possible to prevent the lighting of the EL light-emitting unit 4 from being hindered or to shorten the time until the light is turned off.

[0017]

According to the present invention, the timer circuit having a simple structure is provided in the EL light emitting circuit, so that the EL light emitting circuit is prevented from becoming large and can be incorporated in a small product such as a watch. An EL light-emitting circuit with a timer can be provided.

Also, by providing the timer circuit,
Even if the switch is continuously turned on, the EL is turned off for a certain period of time, so that power consumption can be minimized and battery life can be extended.

Further, since the timer circuit is composed of very few components, an increase in cost can be minimized.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a watch EL light emitting circuit according to one embodiment of the present invention.

FIG. 2 is a plan view showing the structure of the switch shown in FIG.

[Explanation of symbols]

 2 drive circuit 4 EL light emitting part 6 switch 8 timer circuit 10 power storage circuit 12 stop circuit

Claims (3)

[Claims] 1. A timepiece E having a drive circuit for supplying power to an EL light-emitting unit in response to an ON operation of a switch to emit light.
The L light emitting circuit for a timepiece, further comprising a timer circuit for stopping power supply from the driving circuit to the EL light emitting unit when a predetermined time has elapsed from the on operation of the switch. 2. The power supply circuit according to claim 1, wherein the switch circuit is turned on and the storage circuit is charged to an operation voltage when a predetermined time elapses, and a stop signal is transmitted to the drive circuit when the storage circuit is charged to the operation voltage. The timepiece EL light emitting circuit according to claim 1, further comprising: a stop circuit that stops the power supply to the EL light emitting unit by applying the voltage. 3. The switch according to claim 2, wherein when the switch is turned off, the switch is short-circuited to discharge the power storage circuit.
The EL light-emitting circuit for a timepiece described in the above.