JPH01124791A - Switch device for electronic timepiece - Google Patents

Abstract

PURPOSE:To reduce the influence of an alarm driving voltage upon a piezoelectric element for shock detection and to reduce the size by constituting an alarm piezoelectric element and a shock detecting piezoelectric elements as different bodies, and fixing them to a reverse lid plate as one member of a timepiece case. CONSTITUTION:The metallic reverse lid plate 2 is fixed to a time-piece case main body 1. The alarm piezoelectric element 3 for alarm tone generation and the shock detecting piezoelectric element 4 for detecting a shock applied to the timepiece case are formed in individual flat plate shapes and fixed to the reverse lid plate 2. The plane area of the shock detecting piezoelectric element 4 is equal to or smaller than the plane area of the alarm piezoelectric element 3. A timepiece movement 5 consists of a circuit board 5a where a time clocking circuit and a shock detecting circuit are mounted, an upper frame 5b, a lower frame 5c, and a battery pressure member for holding a battery.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a switch device in an electronic timepiece.

[Conventional technology]

The switch structure used in conventional electronic watches is often a mechanical contact method operated by a push-pull or crown. The idea of using this signal as an input signal in a switch was considered, and improvements in technology have made it possible to put it into practical use.

The technical idea regarding the piezoelectric element switch as described above is disclosed, for example, in Japanese Patent Application Laid-Open No. 53-80263.
By using a piezoelectric element fixed to a part of the watch case,
The idea is to activate the electronic circuit of the watch by the impact signal generated by hitting the watch case.

Furthermore, in Japanese Patent Application No. 61-223649, the present applicant fixed a piezoelectric element having two independent electrodes on one surface of a flat plate to a watch case, and applied an alarm signal to one electrode. However, by tapping the watch case while the alarm is sounding, an application was filed to detect the impact signal generated in other electrodes and stop the output of the alarm signal.

[Problem that the invention seeks to solve]

However, the patent application filed by the applicant in 1986-22
FIG. 5 shows a cross section of a piezoelectric element fixed to a part of a watch case according to No. 3649. In FIG. 5, 100 indicates the back cover of the watch case.

101 is a piezoelectric element, and the piezoelectric element 101 has the following configuration. Reference numeral 10-13 is a piezoelectric material, and a power supply electrode 101b is arranged on the contact surface with the watch and case back cover 101, and an alarm electrode 101C and an impact signal electrode 10 are arranged on the other surface.
1d is the arrangement. Piezoelectric element 10 configured in this way
1 is fixed to the back cover 100 of the watch case. ■ Voltage signal for alarm now. When is applied between the power supply electrode 101b and the alarm electrode 101C, a force is generated in the piezoelectric material 101a sandwiched between the alarm electrode 101C and the power supply electrode 101b in the direction of the arrow F'to.

Due to this force FIO, the watch case back cover 100 is also
It is well known that a force F20 on the watch case back 100 is smaller than the force F1o on the piezoelectric material 101a (
It is also well known that this decreases due to the adhesion force between the piezoelectric element 101 and the watch case back cover 100. However, in the same material, the loss due to force transmission is very small.

Therefore, the force F1o generated by the piezoelectric material 101a remains unchanged, and the strain F of the piezoelectric material 101a in the portion narrowed by the impact signal electrode 101d and the power supply electrode 101b. becomes. Therefore, in the shock signal electrode 101d, the piezoelectric material 1
It is also well known that a voltage V20 corresponding to the force F'to of 01a is generated between the power supply electrode 101b.
This voltage 2o is lower than the alarm voltage signal 1o depending on the energy conversion efficiency [(voltage→force) or (force→voltage)] of the piezoelectric material 101a. However, the voltage signal for alarm ■,. In this case, a voltage on the order of IOV generated from an alarm drive circuit in a normal electronic watch is applied.

Therefore, if the energy conversion efficiency is 0.6, the voltage v2o output from the impact signal electrode 101d is 3.6V (
=10VX0.6XO16). It is also well known that the timekeeping circuit of an electronic wristwatch normally operates at a power supply voltage of 3 µm or less. As can be seen from this, the patent application
In No. 3649, the voltage V20 generated in the impact electrode is removed by the level discrimination circuit using this alarm voltage signal Io, but this technology requires a high power supply that is not normally used for electronic watches such as electronic watches. This is a technology that can be used when voltage is applied.

In other words, the technology that attempts to detect only the voltage signal caused by an impact has a problem with the alarm voltage signal V1, which is a noise signal. )
The voltage V20 generated by this is too thick compared to the voltage generated by the impact signal.

The purpose of the present invention is to reduce the voltage V20 generated by the alarm voltage signals ■ and o, which are noise signals, as much as possible (
By doing so, it is possible to provide a switch device that uses impact force with better sensitivity.

[Means for solving problems]

In order to achieve the above object, the present invention includes a first piezoelectric element for generating an alarm sound, a second piezoelectric element for detecting an impact applied to the clock, and a voltage signal generated by the second piezoelectric element. , an electronic timepiece having a detection circuit for detecting a signal generated by an impact and a clock circuit for performing clock timekeeping, etc., wherein the first piezoelectric element and the second piezoelectric element are each in an individual flat plate shape; The piezoelectric element is characterized in that the planar area of the piezoelectric element is the same as or smaller than the planar area of the first piezoelectric element, and is fixed to the watch case.

〔Example〕

Embodiments of the present invention will be described in detail below based on the drawings.

FIGS. 1 to 4 and FIGS. 6 and 7 are drawings of an embodiment of the present invention. FIG. 3 is a sectional view of essential parts showing the sectional structure of the electronic timepiece of this embodiment. Figure 1 shows the 3rd
FIG. 2 is a plan view of the back cover member of the electronic timepiece shown in the figure when viewed from arrow BB. FIG. 2 shows the electronic timepiece shown in FIG. 3 with the back cover member shown in FIG.
- It is a top view seen from A. 4 is a cross-sectional view of the back cover member showing in detail the cross-sectional structure of the back cover member shown in FIG. 1. FIG. FIG. 6 is a system diagram of this embodiment, and FIG. 7 is a waveform diagram of the system diagram (FIG. 6).

First, the structure of this embodiment will be explained. 1 is a watch case body. As shown in Fig. 2, the watch case body 1 has four screw holes 1a for screwing the back cover plate 2. Reference numeral 2 denotes a metal back cover plate that holds the diaphragm of the piezoelectric element. As shown in Fig. 1, a screw hole 2a is provided, and as shown in Fig. 3, it is fixed to the watch case main body 1 with a screw (not shown). ,
It is a piezoelectric element for alarm, and the piezoelectric element 6 for alarm is:
As shown in FIG. 4, electrodes 6b are provided on the upper and lower surfaces of the piezoelectric material 6a.
6C is arranged, and the electrode 6C is fixed to the back cover plate 2 with an adhesive so as to be in contact therewith.

4 is a piezoelectric element for impact detection, and as shown in FIG. 4, electrodes 4b and 4C are formed on the upper and lower surfaces of a piezoelectric material 4a. Further, an electrode 4C is fixed to the back cover plate 2 so as to be in contact therewith. Here, as shown in FIG. 1, the shock detection piezoelectric element 4 has a smaller plane area than the alarm piezoelectric element 3. 5 is a watch movement. 6 is a display glass; It is crimped to the case body 1.The watch case consists of the watch case body 1, the display glass 6, and the back cover plate 2.
It is composed of. The clock movement 5 includes a circuit board 5a equipped with a clock timing circuit and a shock detection circuit, and an upper frame 5.
b, a lower frame 5C, a battery 5d, and a battery pressing member 5e for holding the battery 5d. Further, the battery pressing member 5e is formed with a protrusion 5el that connects the back cover plate 2 and the electrode of the battery 5d, and a protrusion 5e2 that connects the (G) pole of the battery 5d and the circuit of the circuit board 5a.

Reference numeral 7 designates an alarm contact spring for connecting an alarm drive signal from a clock circuit mounted on the circuit board 5a to the electrode 6b of the alarm piezoelectric element B.

Reference numeral 8 designates an impact signal connection spring for connecting an impact signal generated at the electrode 4b of the impact detection piezoelectric element 4 to an impact detection circuit mounted on the circuit board 5a.

Now, as shown in FIG. 3, when the back cover plate 2 shown in FIG. 1 is assembled into the electronic watch shown in FIG. It is connected to the substrate 5a and the back cover plate 2.

Here, as shown in FIG. 4, it is assumed that an alarm drive signal is applied to the electrode 6b of the alarm piezoelectric element B via the alarm contact spring 7. On the other hand, the alarm piezoelectric element 6
The electrode 6C is grounded to the 1) pole via the back cover plate 2. Therefore, the alarm drive signal voltage vl is
The voltage is applied between the electric power 6C and the electrode 6b which sandwich the voltage.

As a result, the piezoelectric material 6a generates force in the direction of arrow F1. The generated force F becomes a vibration force that vibrates the back cover plate 2 in the direction of the arrow F2 due to the fixing force of the piezoelectric element 6 to the back cover plate 2. This vibration force F2 becomes an alarm sound. This photographing force F2 is also transmitted to another impact detection piezoelectric element 4 fixed to the upper surface of the back cover plate 2, as shown in FIG. Due to this vibrational force F, the piezoelectric material 4a of the impact detection piezoelectric element 4 is similarly subjected to a force in the direction of the vibrational force F. As a result, the four piezoelectric elements 4a for impact detection transmit the voltage v2 to the electrode 4b.
This occurs between the electrode 4C and the electrode 4C.

As described above, the impact detection piezoelectric element 4 also generates the voltage 2 due to the alarm drive voltage 2.

To summarize this process, the alarm drive voltage ■ → Vibration force F1 of the alarm piezoelectric element B → Vibration force F2 of the back cover plate 2 →
The vibration force F3 of the piezoelectric element 4 for collision detection becomes → the generated voltage ■2.

As mentioned above, the efficiency of converting the electrical energy of the piezoelectric element into force energy, or vice versa, is generally 0.6 or less, and the piezoelectric element is The efficiency transmitted by the adhesion force between the
It becomes 4V (=10X0.6X0.2X0.2.X0.6), which is very small.

Note that by hitting a part of the watch case with your hand (this causes the back cover plate 2 to bend significantly. As a result, the impact detection piezoelectric element 4 generates a voltage due to the impact.A typical piezoelectric gas lighter As is clear from the fact that even a very small piezoelectric element generates enough voltage to ignite gas, it is clear that by tapping a wristwatch, the voltage generated by a piezoelectric element with a diameter of 10 gates is 5 to 10 V. be.

Therefore, the alarm piezoelectric element 3 requires a large area in order to produce as loud a sound as possible.

On the other hand, the impact detection piezoelectric element 4 does not require a large area.

Therefore, the impact detection piezoelectric element 4 may be smaller than the alarm piezoelectric element 6.

Next, using FIGS. 6 and 7, a method of detecting only a voltage signal generated by an external force shock and inputting it to a timepiece circuit will be described.

FIG. 6 is a system circuit diagram, and FIG. 7 is a waveform diagram showing waveforms at each terminal of the system circuit diagram (FIG. 6).

In Figure 6, 6a1, 6b, 6C14a14b, 4
c and 5d indicate the same components as those explained in FIG. 1, FIG. 2, FIG. 3, and FIG. 4, respectively, so their explanation will be omitted. 10 is an alarm signal amplification circuit, and 11 is a detection circuit for detecting a voltage signal generated by the piezoelectric element 4a. The detection circuit 11 is constituted by the capacitance C'Q of the impact detection piezoelectric element 4 and a resistor RO. Reference numeral 12 denotes a level discrimination circuit which inputs the detection signal A of the detection circuit 11, accepts only signals of a certain level or above from the detection signal A, and outputs a pulse signal of a certain width or above. The level determination circuit 12 is equipped with a field-effect MO for determining the level.
S transistor (hereinafter referred to as MO8 transistor) Tr
, a resistor R1 and a capacitor C1 for determining the pulse width,
It consists of a buffer 12a for pulsing.

16 is a clock circuit. The clock circuit 16 includes an alarm output terminal AL that outputs an alarm signal to the alarm signal amplification circuit 10, a switch input terminal SW, and (g) a power supply terminal VD.
D and day power terminal V8g are provided.

An alarm signal is output from the alarm output terminal AL of the first clock circuit 16 and input to the alarm signal amplification circuit 10. Then, the alarm signal amplification circuit 10 converts it into a voltage higher than the alarm signal AL, for example, IOV as described above, in order to vibrate the alarm piezoelectric element 6.

When the alarm signal amplification circuit 10 applies a voltage signal vI from its output terminal AL″Q to the electrode 3b of the alarm piezoelectric element 6, the alarm piezoelectric element 6 is distorted due to the piezoelectric effect, and as described above, the back cover plate 2 Take a picture.

At this time, in the detection circuit 11, the impact detection piezoelectric element 4
As explained in FIG. 4, a voltage V2 is generated at the electrode 4b due to the vibration force F3.

In the detection circuit 11, a bypass filter circuit is formed by a capacitor CQ and a resistor Rt.

As a result, when the back cover plate 2 is subjected to distortion at low frequencies, the signal generated by the impact detection piezoelectric element 4 is cut off, and only the signal above a certain frequency is output as the detection signal A of the detection circuit 11. do.

Therefore, as explained in FIG. 4, the voltage signal V2 generated by the impact detection piezoelectric element 4 due to the alarm sound is as small as 0.144V.

Here, the voltage waveform of the detection signal A is shown in A of FIG. In A of FIG. 7, A1 is an alarm detection signal by an alarm sound. The voltage value of the detection signal A1 caused by the alarm sound is ■2.

Here, a state in which an external force impact is applied will be explained. When an external force impact is applied, the impact is transmitted to the back cover plate 2 described above, causing it to vibrate. Therefore, the impact detection piezoelectric element 4 is distorted. The impact detection signal generated by this impact is as shown at A2 in A of FIG. The voltage value of the impact detection signal A2 is VgK.

Here, the voltage value ■3□ of the impact detection signal A2 is larger than the voltage value ■2 of the detection signal A1 caused by the alarm sound. The reason for this is clear from the explanation in FIG.

Therefore, the detection signal A passes the impact detection signal A2 detected by the detection circuit 11 and is input to the level discrimination circuit 12. In the level discrimination circuit 12, the MOS
It is input to the gate terminal of the transistor Tr. In this way, the threshold value vth is applied to the gate of the MOS transistor Tr.
When a signal exceeding
It enters the N state, and the B terminal approaches the VD power supply which is (+O)V.

In other words, it is clear from the previous explanation and experiment that the peak value VIIK of the alarm detection signal A1 is much smaller than the peak value VIIK of the shock detection signal A2, as is clear from A in FIG. , and can be set smaller than the critical value ■th, so that the impact detection signal A
A high voltage can be generated by applying a small shock to 2.

Therefore, if the time point at which the voltage of the impact detection signal A2 (K V = t crosses the critical value V t h from high level to low level is Vs, or conversely, the time point at which it crosses from Low level to High level is VIIK2, the alarm detection signal When inputting AI, MOS transistor Tr
The source-gate voltage of is small and is in the OFF state.

Next, at the time of V, , , a signal exceeding the threshold value ■tb is input to the MOS transistor Tr, the source-gate voltage becomes ON, the capacitor C1 is charged, and the B terminal is at the (0) ■ level. become. Then V, τ
At time point 2, a voltage below the threshold value is applied to the gate of the MOS transistor Tr, and the source-gate becomes OFF. Therefore, the electric charge stored in the capacitor C1 is transferred to the discharge characteristic of the capacitor C1 and the resistor R2 (B in Fig. 7).
■88. Shown below. ), the voltage waveform at the B terminal exhibits the appearance shown in FIG. 7B.

Next, a signal as shown in FIG. 7B is sent to the buffer 12a.
is pulsed by the sharp saliva voltage vth to become a pulse signal shown in FIG. The pulse width t of the pulse signal needs to have a sufficient time width for the clock circuit 16 to read, and the pulse width t is set by the respective values of the resistor R1 and the capacitor C1. The clock circuit 16 performs a specified switch operation by reading and inputting a pulse signal.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, the piezoelectric element for alarm and the piezoelectric element for impact detection are made separate and fixed to the back cover plate, which is a part of the watch case. Since the element is not affected by the alarm driving voltage very little (and the area of the piezoelectric element for impact detection can be made small, it is possible to provide an excellent switching device that can be applied to small wristwatches). .

[Brief explanation of the drawing]

1 to 4 and 6 and 7 show one embodiment of the present invention, and FIG. 1 is a plan view of the back cover member of the electronic timepiece shown in FIG. 3, viewed from the inside. Similarly, FIG. 2 is a plan view of the electronic timepiece shown in FIG. 3 with the back cover removed, FIG. 3 is a cross-sectional structural diagram of the electronic timepiece of this embodiment, and FIG. FIG. 5 is a cross-sectional view of the back cover member shown in FIG. 1, FIG. 5 is a cross-sectional view of the back cover member of the conventional technology, FIG. 6 is a system circuit diagram of the present embodiment, and FIG. 7 is a system circuit diagram. Circuit diagram (6th
FIG. 3 is a voltage waveform diagram of each terminal in FIG. 1... Watch case body, 2... Back cover plate, 3... Piezoelectric element for alarm, 4... Piezoelectric element for impact detection. Figure 4 Figure 5 Figure 6 ``'FttlriiJ'' Tube 7 Figure

Claims (1)

[Claims] A first piezoelectric element for generating an alarm sound, a second piezoelectric element for detecting an impact applied to the watch case, and a detection circuit for detecting a signal generated by the impact among the voltage signals generated by the second piezoelectric element. In an electronic timepiece having a clock circuit for timekeeping, etc., the first piezoelectric element and the second piezoelectric element are each formed into individual flat plates, and the planar area of the second piezoelectric element is equal to the area of the first piezoelectric element. A switch device for an electronic watch, characterized in that it is fixed to a watch case with a planar area equal to or smaller than that of the watch case.