JPS5946356B2 - Electronic clock with buzzer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a buzzer mechanism in an electronic timepiece with a buzzer.

The buzzer mechanism in conventional electronic watches with a buzzer consists of bonding a piezoelectric element to a metal diaphragm, one pole of the piezoelectric element is grounded to the power supply voltage, and the other pole is connected to a high voltage boosted by a coil. A method has been used in which a voltage oscillation signal is applied, which is converted into mechanical vibration by a piezoelectric element, and a buzzer sound is generated by a vibrating diaphragm.

However, the number of elements constituted here is large, and among the elements, the coil is large in shape and has low efficiency. Therefore, by implementing the present invention, it is possible to eliminate the need for boosting the coil voltage. , it is possible to obtain an efficient buzzer mechanism with a small number of elements. The buzzer mechanism of the electronic timepiece with a buzzer according to the present invention will be described in detail below.

Figure 1 shows the circuit diagram of the present buzzer circuit, and Figure 2 shows the circuit diagram of the buzzer circuit.
5 is a time chart showing voltage waveforms in the figure.

FIG. 3 shows a cross section of a buzzer mechanism of an electronic watch with a buzzer using the present buzzer circuit. In FIGS. 1 and 2, 1 indicates a piezoelectric element, and 2 and 3 are complementary MOS inverters (C-MOS inverters) for amplification.
The buffers 2 and 3 constitute a drive circuit D for the piezoelectric element 1. Therefore, when the signals f and END as shown in FIG.
The MOS transistor on the channel side is turned on, and a current of iA flows. Then, at time B, iB flows in the opposite direction to that at time A. Therefore, since a voltage E whose polarity alternates between VDD and -VDD is applied to both ends of the piezoelectric element 1, the piezoelectric element 1 is driven with substantially twice the voltage, which is different from the conventional method. This eliminates the need for a boost coil. FIG. 2 shows a sectional view of an electronic timepiece with a buzzer using the buzzer drive circuit shown in FIG.

4 is a piezoelectric element, and electrodes are provided on the upper and lower surfaces of the piezoelectric element 4.

5 is a vibrating body made of metal, a piezoelectric element 4 is bonded to the vibrating body 5, and one electrode of the piezoelectric element 4 is connected to the vibrating plate 5.

Reference numeral 6 denotes a back cover constituting a watch exterior member, and the back cover 6 is provided with several sound emitting holes 6a.

T is a rubber waterproof packing, 8 is a resin auxiliary ring, and the waterproof packing 7 and the auxiliary ring 8 constitute an electrically insulating holding means for mechanically holding the diaphragm 5. As shown in the figure, the diaphragm 5 is sandwiched between a waterproof gasket 7 and an auxiliary ring 8, and is electrically insulated from a metal back cover 6 whose power source is grounded, and maintains waterproof properties. is set up. 9 is the outer body of the exterior, 10
11 is a waterproof gasket, and 11 is an inner frame for fixing the movement 12 to the exterior.

Therefore, the movement 12 is fixed to the outer body 9 via the inner frame 11 by closing the back cover 6. 13,
14 is a coil spring for applying a signal from an integrated circuit built into the movement 12 to the diaphragm 5 and the piezoelectric element 4.

Therefore, signals as shown in FIG. 1 are applied to the coil springs 13 and 14, and each signal is applied to the piezoelectric element 4, and the piezoelectric element 4 starts to vibrate due to each signal.
The diaphragm 5 is vibrated, and the buzzer sound generated by this vibration is emitted as sound to the outside through the sound emitting hole 6a. As described above, by applying a voltage with alternating polarity to both poles of the piezoelectric element using a pair of complementary MOS inverters, the piezoelectric element can be driven with approximately twice the drive voltage. In addition to improving the driving efficiency, the present invention eliminates the need for a coil that conventionally required a relatively large space inside the limited electronic timepiece, making it possible to downsize the electronic timepiece.

Furthermore, the diaphragm to which the piezoelectric element is fixed is made of metal, and this diaphragm is held electrically insulated from the metal back cover, which is connected to one pole of the power source (grounded). If it is mechanically held by means, it is possible to avoid the situation where the power supply is short-circuited by the complementary MOS inverter during driving, and at the same time, it is possible to use the diaphragm as one input terminal of the piezoelectric element. can.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of the buzzer mechanism of the present invention, FIG. 2 is a time chart showing voltage waveforms in FIG. 1, and FIG. 3 is a sectional view of an electronic timepiece with a buzzer. 1, 4... Piezoelectric element, 5... Vibration plate,
E: Voltage, D: Drive circuit, F, D: Signal.

Claims (1)

[Claims] 1. A metal diaphragm for sound generation, a piezoelectric element fixed to the metal diaphragm, each output being connected to both poles of the piezoelectric element, and each input receiving signals of approximately opposite phase to each other. A pair of complementary MOS inverters for applying a voltage whose polarity changes alternately to the piezoelectric element upon input; a metal timepiece exterior member grounded to one pole of the power supply; and the timepiece exterior member. 1. An electronic timepiece with a buzzer, comprising: a holding means for mechanically holding the metal diaphragm in a state where it is electrically insulated from the metal diaphragm.