EP2561409B1 - Element of regulation for a timepiece and a corresponding process - Google Patents

Description

Technical area

The invention relates to a mechanical timepiece whose control element comprises a restlessness, a spiral spring and an electronic circuit with a quartz oscillator.

State of the art

Mechanical watches are driven by a winding spring. This spring is the engine of the mechanical watch: it is wound up either manually or by wearing over the automatic winding mechanism of the watch on the wrist and thus stores the energy. This is then delivered continuously to the wheel train.

The gear train is a kind of gearbox that transmits and translates the great energy of the barrel to small wheels (minute, low floor, second and escape wheel). The escapement acts as a connecting link between the gear train and the balance for the clock transmission and releases the drive energy from the barrel to the unrest via the escapement wheel and the armature and keeps it from vibrating. The escapement, controlled by the control element, frees and stops the gear train at very precise intervals.

The control organ comprises a coil spring and a balance. The balance behaves in a similar way to a pendulum, which is always returned to the rest position with the help of the coil spring, thus ensuring that the clock has the same rhythm. For most modern watches, the balance oscillates at 8800A / h, or eight times a second, or nearly 700,000 times a day. These intervals cause the hands to indicate the "correct time" on the dial.

A disadvantage of the mechanical watch compared to the electronic watch is that the gear of the watch goes through Layer changes, fluctuating temperature, magnetism, dust, are adversely affected by irregular mounting and oiling.

Out EP848842 is a clockwork known whose spring via a gear train a time display and a generator supplying an AC voltage. The generator feeds a voltage converter circuit, the voltage converter circuit feeds a capacitive component, and the capacitive component feeds a reference electronic circuit having a stable oscillator and an electronic control circuit. The electronic control circuit comprises a comparator logic circuit and an energy dissipation circuit connected to an output of the comparator logic circuit and controllable by the comparator logic circuit in their power consumption. One input of the comparator logic circuit is connected to the electronic reference circuit and another input of the comparator logic circuit is connected to the generator via a comparator stage and an anti-coincidence circuit. The comparator logic circuit is adapted to compare a clock signal from the electronic reference circuit with a clock signal from the generator, and controls the magnitude of the power consumption of the electronic control circuit over the amount of power consumption of the energy dissipation circuit, depending on the result of this comparison this way, via the control of the control circuit power consumption regulates the gear of the generator and thus the course of the time display.

The clockwork off EP848842 but requires a relatively complicated electronics, a generator that provides the necessary energy for the operation of the electronics, and relatively much space to install the systems. Another disadvantage of such a movement is that the forces and moments are different than in a mechanical movement, so that the entire movement must be adjusted.

Presentation of the invention

It is an object of the invention to propose an improved control device for a mechanical watch.

It is a further object of the invention to propose a more accurate control device for a mechanical watch.

It is a further object of the invention to propose an electronic control device for a mechanical timepiece, wherein the electronic control element is powered by the mechanical movement and without battery.

Another object is to provide a new control mechanism or auxiliary control mechanism for a mechanical movement that can be incorporated in an existing mechanical movement with minimal changes.

These goals are achieved with a control device that includes a restlessness, a coil spring at least partially made of piezoelectric material, and a gait-regulating electronics.

According to one aspect, there is provided a mechanical timepiece governing device which substantially improves the accuracy of the mechanical governor by electronically stabilizing the oscillating frequency of the disturbance, the energy for the electronics of the governor being provided by the coil spring.

In one aspect, the coil spring of a conventional mechanical timepiece is replaced by a piezoelectric coil spring. The piezospiral spring generates an alternating voltage dependent on the oscillations of the balance and / or the coil spring.

The AC voltage is transmitted to control the vibration frequency of the balance via an electrical connection to an electronic circuit, which can change the stiffness of the coil spring and thus the frequency of the balance system balance / coil spring and thus can regulate. At the same time, the electronic circuit can be fed exclusively by the named piezospiral spring, so that an additional battery is not needed. Although a battery is not necessary, one can imagine that the electronic circuit powered by a solar cell and a small battery or a capacity.

Thus, when the balance is vibrated, an alternating voltage is generated by the piezoelectric materials mounted on the coil spring. So the coil spring works like a small generator. The AC voltage at the output of the coil spring is rectified to feed the electronic circuit.

The stiffness of the coil spring is adjusted by changing the impedance at the output of the piezospiral spring. In a preferred variant, this is achieved by adjusting the value of a capacitance parallel to the piezospiral spring. The greater the value of the capacitance connected in parallel with the piezospiral spring, the smaller the stiffness of the spiral spring. In a preferred embodiment, the adjustable capacitance comprises a number of capacitors which can be switched on and off with switches.

An example of piezoelectric coil spring was made by Tao Dong et al. in "Proceedings of PowerMEMS 2008+ micro EMS 2008", Sendai, Japan, November 9-12 , "A Mems-based spiral piezoelectric energy harvester"; However, this coil spring is not used as a control member for a movement, and the oscillation frequency is not set electronically.

US4435667 describes an actuator with a piezoelectric spiral; this actuator is not used for a movement.

JP2002228774 (Seiko Epson Corp) describes a method for adjusting the oscillation frequency of a piezoelectric coil spring in which the piezo element is either connected to an electrical circuit, or completely separated from this circuit. However, this results in abrupt changes in the impedance associated with the coil spring each time the electrical circuit is connected to or disconnected from the piezoelectric element. Such fast Impedance changes with a large amplitude abruptly modify the electrical voltage at the input of the electronic circuit. The larger the capacitance connected in parallel with the piezospiral spring, the smaller the induced AC voltage at the input of the rectifier. This can cause the voltage at the input of the electronics is no longer high enough to ensure the safe functioning of the electronics. Another problem is that in this embodiment, the agitation oscillates either too fast or too slow, but never at the right frequency. Again, this can lead to problems with the control and even unwanted vibrations. This proves to be detrimental to the accuracy.

In a preferred embodiment of the present invention, the capacitance at the output of the piezoelectric coil spring is set in several stages, on the one hand to be able to change the stiffness of the coil spring in small steps, and on the other hand only to switch the minimum necessary capacity parallel to the piezospiral spring, so that the Voltage at the input of the rectifier is not unnecessarily reduced. In a preferred embodiment, at least one fixed small capacitance in the electronic circuit is constantly connected to the piezoelectric coil spring. This has the advantage that the voltage at the input of the rectifier can be adjusted so that the rectifier works safely and has a high efficiency.

According to another independent aspect of the invention, the electronic circuit for adjusting the impedance at the output of the coil spring comprises an active rectifier, in which diodes are replaced by transistors, and / or a circuit having a plurality of transistors for adjusting the impedance at the output of the spiral spring; at least some of these transistors are driven with an increased voltage, for example, with a voltage that is higher than the voltage of the greater part of the digital components of the electronic circuit. The control of the switch can be realized for example with level shifter; This reduces the ohmic resistance in these switches.

The voltage for driving the transistors in the rectifier and / or in the impedance matching circuit is thus higher than the supply voltage Vdd of the electronic circuit with which the or most digital components of the electronic circuit are driven. As a result, the power consumption of the electronic circuit is reduced, and the transistors have a small ohmic resistance.

The transistors for adjusting the impedance at the output of the coil spring are switched on or off only when the voltage induced by the coil spring is lower than a predetermined threshold, or when the current generated by the coil spring is lower than a predetermined threshold. As a result, energy losses can be reduced.

Further advantageous embodiments are specified in the subclaims.

Brief description of the figures

Fig.1

Eine schematische Ansicht der Regelung darstellt mit den Kapazitäten, den die Kapazitäten zu- und wegschaltenden Schaltern sowie der Komparator-Logik Schaltung, welche die Schalter ansteuern.

Fig.2

Eine schematische Ansicht darstellt der Regelung der Spannung des Kondensators, der die elektronische Schaltung mit Energie versorgt.

Fig.3a

Eine schematische Ansicht der gedruckten Schaltung mit den aufgelöteten Bauteilen zeigt, wobei neben der elektronischen Schaltung grosse Flächen vorhanden sind, auf denen Testpads oder Testkontakte aufgebracht sind.

Fig.3b

Eine schematische Ansicht der gedruckten Schaltung mit den aufgelöteten Bauteilen zeigt, wobei die Testflächen abgetrennt sind.

Fig.4

Eine schematische Ansicht einer Spiralfeder darstellt.

Fig.5a

Eine schematische Ansicht des Querschnitts einer erfindungsgemässen Spiralfeder darstellt.

Fig.5b

Einen Detail des Querschnitts der Spiralfeder mit den verschiedenen Schichten darstellt.

Fig.6

Eine schematische Ansicht der Unruhe, der Piezospiralfeder und der elektronischen Schaltung zeigt.

Fig.7

Eine schematische Ansicht der elektronischen Schaltung darstellt, wobei die Schalter für die Frequenzregelung und den aktiven Gleichrichter sowie der Schalter für die Spannungsregelung der zweiten Kapazität über Levelshifter angesteuert werden.

Fig.8

Eine schematische Ansicht der elektronischen Schaltung darstellt, wobei nur die Schalter für die Frequenzregelung sowie der Schalter für die Spannungsregelung der zweiten Kapazität über Levelshifter angesteuert werden.

The invention will be explained in more detail with reference to the attached figures, in which:

Fig.1

A schematic view of the control system is shown with the capacitors, the capacitors switching on and off the capacitors, and the comparator logic circuit which controls the switches.

Fig.2

A schematic view illustrates the regulation of the voltage of the capacitor, which supplies the electronic circuit with energy.

3a

A schematic view of the printed circuit with the soldered components shows, in addition to the electronic circuit large areas are present, on which test pads or test contacts are applied.

3b

A schematic view of the printed circuit with the soldered components shows, wherein the test surfaces are separated.

Figure 4

A schematic view of a spiral spring represents.

5a

A schematic view of the cross section of a spiral spring according to the invention.

5 b

Represents a detail of the cross section of the spiral spring with the different layers.

Figure 6

A schematic view of the restlessness, the piezospiral spring and the electronic circuit shows.

Figure 7

A schematic view of the electronic circuit is shown, wherein the switches for the frequency control and the active rectifier and the switch for the voltage control of the second capacitance are controlled by level shifter.

Figure 8

A schematic view of the electronic circuit is shown, wherein only the switches for the frequency control and the switch for the voltage control of the second capacitor are controlled by level shifter.

Ways to carry out the invention

A control device according to the invention comprises a conventional balance 30, a piezoelectric coil spring 20 (FIG. FIGS. 4 . 5a and 5b ) and an electronic circuit 40 for controlling the accuracy of a mechanical movement with a piezoelectric coil spring. This control element is conventionally connected via an escapement, not shown, with the gear train of a mechanical movement that supplies the required energy, and whose gear is thus regulated.

The piezoelectric spiral spring 20 consists entirely of a piezoelectric material, or of a material coated with at least one piezoelectric layer, preferably of a semiconductor material (for example silicon) 200, which is at least partially ( Fig. 5a and Fig. 5b ) is coated with a piezoelectric material 202-207 and an electrode 208. 202 is a seed layer, 203 and 204 are intermediate layers of AIGaN and AIN, 205 is the semiconductor layer (for example, GaN), 206 is an intermediate layer of AIN, 207 is another piezoelectric layer of GaN for example, and 208 is an electrode. The piezospiral is advantageously designed as a bimorph piezoelectric element, but other designs are conceivable.

The piezoelectric spiral spring can be produced, for example, from a wafer, for example from a wafer made from silicon. By using appropriately n-doped or p-doped silicon 200, the wafer is highly conductive, and the core of the piezospiral spring made of silicon can be used directly as an electrode.

The coil springs are structured on the wafer. With the Deep Reactive Ion Etching DRIE method, vertical structures can be easily realized in silicon.

After patterning the coil springs on the wafer, by controlled oxidation of the wafer, a thin oxide layer of the order of 1-3 μm is formed on the surface of the coil springs. This rounds the edges and smooths out the bumps in the vertically etched surfaces.

This oxide layer is then etched away, on the one hand to ensure a good electrical contact between the conductive core 200 of the spiral spring and the piezoelectric layer 205, 207, and on the other hand to achieve a good quality of the piezoelectric coating.

Subsequently, at least one piezoelectric layer 205, 207 having the desired layer thickness is applied to a seed layer 202 made of AIN on the wafer and thus onto the coil springs freed of an oxide layer, for example a layer of aluminum nitride. This layer 205, 207 ideally has an identical thickness throughout the coil spring. Thus it can be prevented that the coil spring deforms by the different thermal expansion coefficients of the silicon and the piezoelectric material in an undesired manner.

After the application of the piezoelectric layer (s), the electrodes 208 are still applied. One possibility is first to coat the entire wafer with a thin adhesive layer having a thickness of a few nm of chromium or titanium in order then to apply thereto a layer 208 of, for example, nickel or nickel / gold in a thickness of 100-500 nm. Thus, the entire wafer and the coil springs are provided on the entire surface everywhere with an electrically conductive layer.

After applying the electrodes 208, the electrode material on the top and bottom of the wafer is removed with a directed etching process, so that only electrodes 208 remain on the vertical side walls of the coil spring. After breaking a predetermined breaking point on the spiral roll and a predetermined breaking point of blocks then the electrodes 208 are separated on the inside and outside of the coil spring and the coil spring is ready for installation in the movement.

This piezoelectric coil spring is then mounted in place of a conventional coil spring in a mechanical movement. When the piezoelectric coil spring 20 vibrates, the piezoelectric material generates an electrical output signal V _gen AV _gen B, with which an electronic circuit 40 is fed on a printed circuit board 400. By changing an impedance which is switched in parallel to the coil spring 20, the rigidity of the piezospiral spring can be changed, and Thus, the oscillation frequency of the piezoelectric coil spring and the restlessness can be controlled by the electronic circuit 40.

An example of an electronic circuit 40 for controlling the oscillation frequency of a piezoelectric coil spring 20 is disclosed FIG. 2 , and in detail FIG. 7 . 8th shown. Two electrodes are connected to the piezomaterial on the piezospiral spring 20 and deliver an AC voltage V _gen AV _gen B. The coil spring thus works like a small generator.

The frequency of the output signal V _gen AV _gen B is controlled by a frequency control circuit 22, so that the gear of the mechanical movement is controlled.

A rectifier circuit 23 converts the AC voltage into a DC voltage V _dc , and a voltage regulation circuit with the transistor 25 regulates the voltage V _{dd of} a capacitance, by which the electronic circuit 40 is then fed. A first capacitive component 24 is preferably used as energy storage or energy buffer. The first capacitive component 24 either directly or via a second capacitive component 26, which is kept at a regulated voltage, feeds the electronic reference circuit with a stable quartz oscillator 1 and a frequency divider 2. The stable oscillator has an oscillating quartz whose oscillation defines a reference frequency , All components except the quartz oscillator and the external capacitors can be constructed as an IC 40; most digital components in the IC can be fed with a low supply voltage V _dd .

Since the AC voltage that can be generated with a piezoelectric element 20 may be relatively high, no voltage multiplier is needed to power the IC 40.

The electronic circuit 40 can only further reduce the frequency of the restlessness.

Setting / regulating the frequency

On the one hand, the oscillation frequency of restlessness and piezospiral spring 20 can be influenced by the piezospiral spring 20 having to deliver a lot of electrical power. This could for example be done by an ohmic resistor is connected in parallel with the piezospherical spring, or by an ohmic resistance parallel to the first capacitor 24, which is fed from the piezospiral spring via the rectifier 23, is switched. The disadvantage of this solution, however, is that the change in frequency is on the one hand only small, of the order of 0.5% or less, and that on the other hand, the amplitude of vibration of restlessness is very small, because energy is permanently destroyed by the ohmic resistance.

A much larger frequency change in the combination of restlessness and piezospiral spring can be achieved by the impedance changing circuit 22 varying the capacitance which is switched in parallel with the piezospiral spring 20. The greater the capacity, the smaller the stiffness of the piezospiral spring 20 and thus the oscillation frequency of the system. Frequency changes of the order of 1-2% can be achieved. This corresponds to a correction possibility of 10-20 minutes per day.

In a variant, not shown, both electrical connections of the piezospiral spring 20 are each connected via a capacitance to the ground, wherein at least one capacitance is varied.

In one embodiment, the electronic control circuit 40 has a comparator logic circuit 4, whose one input to the electronic reference circuit 1, 2 and the other input via a zero crossing of the AC voltage V _gen AV _gene B detecting comparator stage 5 and an anti-coincidence circuit 3 is connected is. The anti-coincidence circuit 3 is essentially an intermediate memory which prevents the simultaneous occurrence of pulses on both inputs of the comparator logic circuit 4. An exit of the Comparator logic circuit 4 controls the switching on and off of the capacitances in the impedance varying circuit 22.

The impedance varying circuit 22 is constructed in this example from a plurality of equal small capacitances 21, 222, 223, 224, 226, 228 (capacitors). However, the capacitances can also have different values, for example, the capacitance values can be selected such that the smallest capacitance has a value of 1nF, the second capacitance a value of 2nF, the third capacitance a value of 4nF and the fourth capacitance a value of 8nF , The comparator logic circuit 4 controls the impedance of the impedance varying circuit 22 by changing the number or combination of the capacitances connected in parallel to the piezospiral spring 20. In this way, the impedance of the electronic control circuit 40 can be controlled in small steps in a size range predetermined by the number and the value of the capacitances.

The comparator logic circuit 4 compares a clock signal A coming from the electronic reference circuit 1, 2 with a clock signal B originating from the piezoelectric generator. Depending on the result of this comparison, the comparator logic circuit 4 controls the magnitude of the impedance of the electronic control circuit via the Number or combination of parallel to the piezospiral 20 connected capacitances 21, 222, 224, 226, 228. In this way, the control of the impedance of the gear of the piezospiral spring 20 and balance and thus the gear of the time display is regulated. The control is designed so that the gear of the time display is synchronized in the desired manner with the reference frequency supplied by the quartz crystal 1.

In order to realize a control circuit that is as energy-efficient as possible, it makes sense to implement the comparator logic circuit 4 with the aid of counters (not shown).

One possibility is to connect the one input of an up-down counter to the output of the comparator 5, which has the phase V _gen A, V _gene B of the induced voltage of the piezospiral spring 20, for example, the zero crossing of the AC voltage detected to connect; and to connect the other input of the up-down counter with the reference circuit 1, 2. The signals from the comparator 5 are added to the count, and the signals from the reference circuit 1, 2 are subtracted. The value counted by the counter thus corresponds to the difference between the number of pulses from the piezospiral spring 20 and the number of pulses from reference circuit 1, 2.

The incoming signals, which are obtained from the counter in the comparator logic circuit 5, are synchronized with the anti-coincidence circuit 3 so that never simultaneously a UP pulse from the comparator 5 and a DOWN pulse from the reference circuit 1, 2 arrive at the counter.

If both frequencies are identical, the count will only increase by one step as soon as the UP signal from the comparator (which measures, for example, the zero crossing of the piezospiral induced voltage) arrives at the counter and again decreases by one step as soon as the reference signal DOWN from the reference circuit 1, 2 arrives. Now, if the unrest swings too fast, more UP pulses will arrive as DOWN pulses over time, and the count will increase. In a simple embodiment, switches 221, 223, 225, 227 (transistors), which connect or disconnect the capacitors 222, 224, 226, 228 in parallel with the piezospiral spring 20, can now be activated directly from the output of the counter. The greater the phase shift, the greater the count, and the more capacitances are connected in parallel with the piezospiral spring 20. However, the greater the impedance connected in parallel to the piezospiral spring 20, the more the oscillation frequency of the restlessness is slowed down.

Thus, in short-term disturbances, for example, if the oscillation frequency of restlessness is too low in the short term, the scheme can safely operate below a certain count none of the turn-off capacity 222, 224, 226, 228 connected in parallel to the piezospiral 20. This can be realized by, for example, counter stage 0-7 no capacity (or only the fixed capacitance 21) capacitance is connected in parallel to the piezospiral spring 20, but from counter reading 8-15 the corresponding number or combination of capacitors is connected in parallel, ie at count 8 is an additional capacity In parallel with the piezospiral spring, with counter reading 9 two additional capacitors are connected in parallel, with count 10 three, etc., if capacitances with equal capacitance values are used.

When using binary capacity value capacitances, the switches 221, 223, 225, 227 for connecting and disconnecting the capacitors 222, 224, 226, 228 can be driven directly from the binary counter in the comparator logic circuit 4. With this principle, a simple variant of a control can be realized, which also consumes very little power. However, it may be that the second hand may have a deviation of up to 1s, since the maximum number of capacities in this example is only turned on when the counter 7 has received UP pulses more than Down pulses. However, 8 RPM pulses are equivalent to one second on the dial when using 4Hz restlessness.

The size of the counter in the comparator logic circuit 4 can be chosen freely, but it is reasonable to use a counter which can cover a range of +/- 2-4 seconds.

Lossless switching of capacities

Ideally, the capacitances 222, 224, 226, 228 are switched on or off only when the induced voltage at the output of the piezospiral spring 20 is very small or zero. This has the advantage on the one hand that the electrical losses can thus be minimized. Another advantage is that the polarity of the capacitances must not be detected and / or stored beforehand. Yet another advantage is that so per capacitance 222, 224, 226 and 228 only one switch 221, 223, 225 and, 227, consisting of a P-channel and an N-channel transistor, the are connected in parallel, needed. The capacities can all be interconnected with the one electrical connection, only one switch per capacity is required for the respective other connection. Thus, on the one hand the electrical resistance can be minimized, and on the other hand, fewer outputs for the switching transistors 221, 223, 225, 227 must be provided. This allows the construction of a smaller printed circuit 400, as well as the use of a chip 40 with fewer terminal pads.

The switching of the capacitances at the zero crossing (when the voltage induced by the piezospiral spring 20 is 0 or only a few mV) can be realized by synchronizing the switching operation to the zero crossing comparator 5 which detects the zero crossing of the voltage at the output of the spiral spring. From the comparator logic circuit 4, the information about the combination of zuzuschaltenden capacitors is supplied, and the next sign change of the generator voltage, the switches 221-227 for the connection of the capacitances 222-228 are driven with this information until the next sign change of the Piezo generator 20 supplied voltage at which then the switches for the next cycle are driven with the information from the comparator logic circuit.

The switching on or off of the capacitances 222-228 can also take place during the charging of a first capacitor 24 at the output of the rectifier 23. Then, the output from the piezoelectric generator 20 voltage V _gen AV _gen B over a certain period of time is virtually constant, since the charging capacitor 24 is charged and the internal resistance of the piezospiral spring 20 is very high. If a small capacitance 222 to 228 with the correct polarity is switched on, this does not change the induced voltage. So no electricity will flow, and the system will not take energy from it.

The switching of the capacitances 222 to 228 must be synchronized in this case to the charging process. The comparator logic circuit 4 determines the combination of zuzuschaltenden capacity, and during the next charging process, this combination of capacitances is switched to the piezospiral spring.

However, in order to avoid or minimize the transient losses, the capacitors 222 to 228 in this variant must be connected with the correct polarity. The applied polarity can either be stored or determined with additional comparators. A disadvantage of this solution, however, is that then per switch 222 to 228 each 2 switches must be used. This means that 2 outputs per IC are needed on the IC 40, and the number of tracks on the printed circuit 400 will be larger accordingly.

Put simply, the capacitances 222 to 228 are ideally switched on or off parallel to the piezospiral spring 20 if the voltage across the piezospiral spring 20 and the voltage at the corresponding capacitor 24 are approximately equal, and if this voltage is more than a few to a few dozen mV must also be the same polarity.

Control with 2 counters

An even more elegant solution for the control can be realized by, on the one hand, combining a counter in the comparator logic circuit 4, as described above, with a second small counter. If the meter reading is between 0 and 7 for the large meter, no additional capacities 222 to 228 will be connected in parallel. When counting between 7 and 8, the number of capacitors connected in parallel is determined by the small counter. And if the count of the large counter is greater than 8 all available capacitances are connected in parallel with the piezospiral spring 20.

In this variant, therefore, the phase shift between the UP pulse of the piezospiral spring 20 and the subsequent DOWN pulse from the reference circuit is measured with the small counter. The larger the phase shift is, ie each size Time is between the UP pulse and the DOWN pulse, the greater the value of the combination of the capacitances, which are switched parallel to the piezospiral spring.

The small counter is operated for example with 64Hz. Each UP pulse starts the counter at 0, and the counter is stopped by the subsequent DOWN pulse. The value at the output of the small counter is latched after the input of the DOWN pulse, and at the next zero crossing of the AC voltage, when an UP pulse is again generated, the corresponding combination of capacitances is switched in parallel with the piezospiral spring with the latched value from the small counter. With count 1-7 no capacity (or only the fixed capacity 21) is switched on, with count 8-15 an additional capacity is switched on, with count 16-23 a second additional capacity is switched on etc. (if the capacities are all the same size ). The regulation takes place in this case in the range of 1 / 8s, which is barely noticed by the user of the clock, for the user, the clock will always indicate the exact time.

The small counter can also be operated at a much higher frequency, for example, 1024Hz. With each UP pulse, the counter is started at 0, and with the DOWN pulse, the counter is stopped and the value of the count is stored to switch the corresponding combination of capacitances parallel to the piezospiral spring 20 at the next UP pulse.

Adjust the induced voltage

If a capacitor 21, 222, 224, 226 or 228 is connected in parallel to the piezo spring, the induced voltage at the output of the piezospiral spring 20 is influenced as described above. A large capacitance results in a small induced voltage, a small capacitance or no capacitance connected in parallel with the piezospiral spring 20 gives a large voltage at the input of the rectifier 23. Thus, the voltage V _gen A, V _gen B induced by the piezospiral spring 20 can be adjusted by means of a capacitance 21 connected in parallel with the piezospiral spring 20. On the one hand, this may be necessary so that the induced voltage is in a range favorable for the electronics 40. The induced voltage must not be too high, as otherwise protective diodes will be switched on at the inputs on the IC 40, resulting in a loss of energy. On the other hand, the induced voltage should be higher than the minimum operating voltage, which is necessary for a safe functioning of the electronic circuit.

With a capacitance 21 connected in parallel with the piezospiral spring 20, the desired induced voltage can be set. A first small capacitance 21 in the value of 1-10nF can be switched fixed parallel to the piezospiral spring, so that the voltage at the input of the rectifier 23 is in the desired range and does not exceed a maximum value.

It is also possible to use only one, for it a big capacity for the control of frequency of restlessness. This capacity must be so large that the frequency of the restlessness / spiral spring with the capacity switched on is in any case smaller than the nominal frequency. But since it is not known exactly how big the capacity has to be, this capacity will have to be chosen too big. But this has the disadvantage that the induced voltage of the piezospiral when connecting the capacitance is much smaller, depending on the piezospiral spring and the capacity used, and thereby the securing of the power supply of the electronic circuit is difficult. The voltage at the input of the rectifier can even be so deep that a safe functioning of the electronic circuit can no longer be guaranteed.

Therefore, it is advantageous to use more than one capacity for the control. Then only the capacitance value which is necessary to obtain the correct oscillation frequency of the rest / coil spring is switched on, and the induced voltage at the input of the electronic control circuit is not unnecessarily reduced.

Active rectifier

The electronic circuit 40 must be able to operate with minimal power consumption. This is achieved by at least one passive component (for example a diode for the rectifier) of the rectifier circuit 23 being at least temporarily replaced by an active structural unit (for example a switch controlled by a comparator 7 or 8) 230 ', 231', 232 ', 233'. is replaced with a smaller in the forward direction electrical resistance.

The switch 230 ', 231', 232 ', 233' may be a field-effect transistor and may be connected in such a way that, in its blocked state, part of its structure acts as a diode. In this way, all four diodes of the rectifier 23 are replaced by active switches. Voltage losses across the switch are at least an order of magnitude less than voltage losses across the diode. The voltage drop across a diode can be several hundred mV. However, the voltage drop across the channel of a field effect transistor is only a few mV.

The charging of the first capacitor 24 takes place in the start-up phase of the movement on the subject with a high voltage loss diodes. In the further course, as soon as the comparators 7, 8 function, the diodes are replaced by the active components, so that the voltage loss can be minimized, which is much cheaper energetically than charging via the diodes. In this way, the energy reserve of the movement is used more economically and increases the power reserve.

The charging of the first capacitive component 24 thus takes place only in the start-up phase of the movement on the subject with a high voltage loss diodes.

The first comparator 7 compares the electrical potential V _dc at the terminal of the first capacitive component 24, which is not at ground potential, with the electrical potential V _gen B of the non-ground potential load-side terminal of the rectifier 23. The first switch 230 'is closed by the first comparator 7 only when the voltage of the first capacitive device 24 is sufficient to operate the first comparator 7 and the electrical potential V _dc at the ground-free load-side terminal of the rectifier 23, for further charging of the first capacitive device is high enough.

The voltage value of the first capacitive component 24, which is sufficient for operating the first comparator 7 and for operating a second comparator 8 present in the rectifier 23, is 0.7 V in this exemplary embodiment. Once the first capacitive component 23 is connected via the passive components (diodes). is charged to at least 0.7 V, the power source and thus also the comparators 7,8. The first comparator 7 closes as soon as the voltage V _gen B delivered by the piezospiral spring is higher than the voltage V _{dc of} the first capacitive component 24, ie it closes the first switch 230 'or opens the first field effect transistor. As soon as the voltage V _genB delivered by the piezospiral spring 20 again _drops below the voltage V _{dc of} the first capacitive component 24, the first comparator 7 closes the first field effect transistor 230 '. If the voltage V _genB delivered by the piezospiral spring 20 again _rises to a sufficiently large value, the first comparator 7 opens the first field-effect transistor 230 'again and so on. However, the voltage drop across the channel of the first field effect transistor 230 'is only a few mV compared to the diodes. The efficiency of the rectifier with the active elements is thus substantially higher than that of a rectifier 23 with passive elements. The voltage loss is thus significantly reduced by the use of an active rectifier.

But if only small voltages and currents are switched, it may be that a swinging or bouncing of the combination comparator / switch arises. The comparator 7 (or 8) measures a voltage difference, but once the switch 230 'is closed, the voltage drop across the switch 230' is so small that the comparator 7 reopens the switch. As soon as the switch is opened detected the comparator again a voltage difference, and the switch is closed again. Thus, the system can oscillate switch / comparator, which in extreme cases may result in the capacitive device not being charged with enough voltage to ensure the functioning of the electronic circuit. In any event, the efficiency of the rectifier 23 will degrade as the comparator / switch system begins to bounce or oscillate.

On the one hand, this can be prevented by using comparators 7, 8 with a sufficiently large offset and a sufficiently large hysteresis. This also has the advantage that the piezoelectric generator 20 is always connected in one way or another with the first capacitor via a switch with a more or less large internal resistance as soon as the induced voltage of the piezospiral spring 20 is greater than the voltage at the first capacitor.

Another way to avoid this effect is to measure during the time T1 with the comparator 7, 8 (measuring phase), whether the switch 230 '(or 231', 232 ', 233') must be closed or remain open can. If the comparator 7 (or 8) has detected a voltage difference at which the voltage generated by the piezoelectric generator in front of the transistor is greater than the voltage of the capacitive element, the switch is closed during the time T2 (switching phase).

Subsequently, the switch 230 '(or 231', 232 ', 233') is opened again and measured again during the time T1 with the comparator 7, 8, whether the switch during the next time T2 must be closed or left open. In this way, bouncing or vibration of the active diodes can be avoided.

Said control circuit contains at least one memory means which stores in the first phase (T1, measuring phase) with the switch disabled, at least one control signal which is to be applied to said switch, wherein further in the second phase (T2, Switching phase) of said switch is controlled by said control signal.

If the voltage supplied by the piezoelectric generator 20 is not high enough to supply the electronic circuit 40 with sufficiently high voltage after rectification with the active rectifier 23, a voltage converter circuit with a rectifier, for example a voltage doubler circuit, can be used instead of the simple rectifier 23. However, this has the small disadvantage that more than one external capacitive element is required, which results in an increased space requirement for the electronic circuit.

The rectifier 23 could also consist only of passive diodes.

Minimum power consumption / Maximum amplitude independence

The oscillation amplitude of the restlessness of a mechanical clock can vary relatively strongly. When the elevator spring is fully wound up, the escape wheel transmits a large drive torque to the turbulence via the armature. In this case the restlessness has a large oscillation amplitude. Due to the piezo spring, a relatively high voltage is generated in this case. If only little drive torque is transmitted to the restlessness, for example, when the drive spring is only slightly raised, accordingly, the vibration amplitude of the restlessness and thus the voltage generated by the piezoelectric spring is relatively small.

The electronics must also be able to be operated with a low power consumption even at different high AC voltages from the piezospiral spring 20.

A first possibility is that at least a substantial part of the electronics 40 on the integrated circuit 400 is operated with a regulated voltage, for example the Quartz oscillator 1 and the frequency divider 2, the anti-coincidence circuit 3 and the comparator logic circuit 4, the comparators 5 and 11, possibly also the comparators 7, 8. This ensures that even at a high voltage at the first capacitor 24, the IC 40 with a minimum power consumption can be operated. This has the advantage that even with a large amplitude of the restlessness and thus a large induced voltage from the piezoelectric generator 20 and thus a high voltage at the output of the rectifier 23, the power consumption of the IC will not rise significantly.

A second possibility is to regulate the supply voltage for the integrated circuit 40. The easiest way to do this is by controlling the voltage of the capacitance 26 which powers the electronics. By the (active) rectifier 23, the electric voltage V _gen generated by the piezoelectric spring 20 is rectified and the capacity is charged. The voltage of V _dd can be regulated by turning off the rectifier above a certain level of V _dd and no longer charging the capacitance, although the voltage from the piezo generator is higher at the moment than the voltage at V _dd . For example, a possible upper limit for the V _dd might be 1.2V.

A third possibility is that a first capacitor 24 is fed by the rectifier 23. In this case, this first capacitor 24 is always charged via the rectifier 23 from the electric power supplied by the piezospiral spring 20. There is a second capacitance 26 which powers the electronic circuit 40. This second capacitor 26 is now regulated to a certain voltage V _dd . This can be done, for example, by making a switch 25 at certain intervals, for example 8 times per second, an electrical connection between the first capacitor 24, which has a voltage between 1.2 and 5V, and the second capacitor 26, if after the last charging the voltage at the second capacitor 26 has fallen below the desired value _Vdd . As soon as the desired voltage, for example 1.2V, has been reached at the second capacitor, the charging process is interrupted. Or a lower V _low and an upper voltage V _high can be defined. When the voltage is on the second capacitance is lower than V _low , the switch is closed between the first and second capacitances and the second capacitance is charged by the first capacitance. When the voltage on the second capacitor 26 then rises above the value of V _high , the switch 25 is opened again.

A fourth possibility is to vary the length of the charging window, that is the time during which the capacitor 26, which supplies the supply voltage V _dd for the integrated circuit, can be charged at all. The higher the V _dd , the shorter the loading window becomes. A small charging window gives a relatively small V _dd even at high input voltages from the piezo generator. In this way, the amount of voltage on the capacitor 26 can also be limited.

Another advantage of the regulation of the supply voltage for the integrated circuit 40 is that the piezospiral spring 20 no longer has to be adapted so precisely to the electronics 40. The piezospiral spring 20 must provide only a minimum voltage V _gen during operation sufficient to safely operate the electronics 40 and to control or control the pace of the agitation. If the piezoelectric generator 20 delivers a voltage which is greater than necessary for safe operation, the power consumption of the electronics will therefore not be higher.

Driving the switching transistors 230 ', 231', 232 ', 233' for the rectifier 23 with higher voltage than the supply voltage Vdd of the IC 40th

In order that the control signals for the control of the electronic switching elements / transistors 230 ', 231', 232 ', 233' may be used on the part of the electronic circuit with the higher voltage, these signals must be from the part of the electronic circuit 40 with the low voltage be brought by means of level shifters 10 to a higher voltage V _dc .

The analog circuit with current sources and oscillator 1 and comparators 5, 7, 8, 11 and the logic circuit 4 and the frequency divider 2 and the anti-coincidence circuit 3 is at a low voltage V _dd , for example 200mV above the minimum voltage at which the electronic circuit 40 still safe works, feeds.

The switches 230 ', 231', 232 ', 233' in the rectifier 23, the switches 221, 223, 225, 227 for changing the impedance (by switching capacitors 222-228 on or off), feeding the level shifters 9, 10 12 and the switch 25 needed to supply the low voltage part of the circuit are operated at a higher voltage V _dc , typically between 1.2 and 5V.

When the supply voltage for the integrated electronic circuit 40 is regulated to, for example, 1.0V by controlling the second capacitance 26 to this voltage, but the induced voltage across the piezospiral spring 20 is higher than the 1.0V, and the first capacitance 24 to, for example 5V is charged, the switching transistors 230 ', 231', 232 ', 233' in the rectifier 23 must also be controlled with 5V. This can be done by bringing the control signal for the switching transistors 230 ', 231', 232 ', 233' by means of level shifters 10 to approximately the same voltage as the voltage to be switched. The level shifters are fed by the first capacitor 24, which is loaded by the piezoelectric generator 20.

If the first capacitor 24, which is charged directly by the piezospiral spring 20 via the active rectifier 23, is kept at approximately 1 V by stopping the charging as soon as the desired voltage V _{dc is} reached, the transistors 230 ', 231 ', 232', 233 'are still driven in the rectifier with a voltage which is approximately the same size as the voltage to be switched from the piezoelectric generator. This can be done by internally providing a boost circuit, such as a voltage doubler or quadrupler. Then, the logic signals that drive the switch / transistors, by means of Level shifters 9, 10, 12, which are fed by the internal voltage booster circuit, raised to an increased voltage level V _dc .

However, there is also the possibility of the comparators 13, 14 for the rectifier with the higher voltage V _dc from the first capacitor 24 to the rectifier 23 (see FIG. 8 ) to operate. Then the switches 230 'to 233' for the rectifier 23 can be controlled directly via the comparators 13, 14, in which case no level shifters are necessary for the rectifier.

Driving the switching transistors for the impedance change with higher voltage than the supply voltage V _{dd of} the IC 40th

When the resistance across the switches 221, 223, 225, 227, which turn on or off the capacitances 222, 224, 226, 228, becomes too large, for example, 1Mohm or greater, the electrical losses become large and the oscillation amplitude of the restlessness then becomes far too small. A safe functioning of the movement is then no longer guaranteed.

So that the lowest possible electrical resistance can be ensured via the switching transistors 221, 223, 225, 227, at least one P-channel transistor and one N-channel transistor are connected in parallel per switch. Via level shifters 9, which are supplied with a sufficiently high voltage V _dc as described above, these transistors are activated for the connection and disconnection of the capacitances 222 to 228. The logic signals from the comparator logic circuit 4, which drive the switch / transistors are so by means of the level shifters 9, which are fed either by the higher voltage V _dc at the output of the first capacitor or by an internal voltage booster circuit to an increased Raised voltage level.

Limitation of the maximum amplitude

For movements with an automatic elevator, it may happen that the elevator spring is pulled up too much and Accordingly, too high a torque is delivered to the movement. A high torque on the elevator spring generates a large amplitude at the unrest. Too big an amplitude is not desired. In the case of equipped with a piezospiral 40 clockwork leads a large amplitude to a large induced voltage, and thus to a relatively large voltage across the capacitor 24, which is fed from the rectifier 23. But as soon as this capacity is loaded, for example by switching a resistor in parallel with the capacitance, the voltage across the capacitance will decrease and the piezoprial spring will be loaded more. This leads to the oscillation amplitude of the restlessness becoming smaller, which in this case is desired. It is therefore sufficient to measure the voltage at the first capacitor 24 after the rectifier 23, and to switch a resistor, not shown, parallel to the capacitor 24 when a certain voltage is exceeded, so as to limit the amplitude.

Minimizing power consumption comparators

Comparators are used to measure different signals. Since the system is already largely stabilized by the mechanical oscillator, the times are known when the different values are needed. So it is possible to work with a reduced number of comparators. The inputs and outputs of the comparators are then switched differently depending on the phase.

Another option is to turn off certain comparators when they are not needed. Even so, electricity can be saved. If, for example, the comparator 5 for the measurement of the sign change of the induced voltage of the piezator (zero crossing) is switched off after the switching process for 1/16 seconds, since the next zero crossing takes place only after 1/8 second (4Hz restlessness), thus electricity can be saved become. The functioning of the movement is nevertheless ensured, since the vibration frequency is already largely stabilized by the restlessness / spiral spring.

After switching on the comparators they need a certain time until the desired operating point is reached. In order to prevent the comparators from supplying false signals during this period, the output of the respective comparator is not enabled until the operating point of the corresponding comparator has been reached. This can be realized by only after a predefined period of time after switching on the comparator, the output of the comparator is enabled.

Power on reset (POR)

With a POR circuit (in short: POR), not shown, it is ensured that the electronic control circuit 40 can safely start, does not require too high a starting current, and does not get stuck in the startup process. In the process, the elements that are required for the particular phase of the startup process are activated, or those elements that are not needed at that moment are activated, or some elements are put into a startup mode.

In order for the electronic control circuit 40 to start safely, it must be ensured that when the circuit starts up, the active rectifier 23 is put into a start-up mode, as long as the quartz oscillator 1 does not yet work. The POR serves to operate the rectifier 23 with the comparators and the switches (for example field effect transistors), even without the oscillator 1 functioning.

At the very beginning of the start-up phase, a portion of the switches 230 'to 233' operate as simple diodes, and in this phase at least one capacitor 24 is charged via these lossy diodes. As soon as the internal power source on the IC works, the comparators will start to work as well. In this phase, the switches are then controlled directly by the comparators.

So that there is a favorable AC voltage for starting the electronic circuit, the POR can also be used to switch one or more capacitors 222 to 228 parallel to the piezospiral spring 20 during the start-up phase. Thus, the induced voltage can be set to a certain value favorable for starting the electronic circuit 40. As soon as the quartz oscillator 1 works and the POR disappears, the switching on and off of the capacitances 222 to 228 is again used to regulate the oscillation frequency of the disturbance.

The POR also serves to ensure safe start-up of the quartz oscillator 1 and to ensure that when starting the crystal oscillator 1 not too much power is needed on. This can be realized by first charging at least one capacitor 24 with the aid of the rectifier, first with the passive elements (diodes), and once the power source has started up with the active elements (comparators and switches). Only when the capacitance which supplies the quartz oscillator is charged to a minimum voltage, for example 1 V, is the quartz oscillator 1 started. The current can reach 200nA for one second. However, this is not a problem since most of the electrical power is supplied by the already charged capacity. With a capacitance of 1uF and 1V, this results in approximately a voltage drop of 0.2V. Thus, a safe starting of the quartz oscillator can be ensured without the system restlessness / coil spring is loaded too much by a high starting current.

The POR also ensures that the second capacitor 26 is supplied with sufficient electrical energy by the first capacitor 24 during the startup process. It is also possible to feed the quartz oscillator 1 exclusively by the second capacitor 26 and to start the oscillator 1 as soon as the second capacitor 26 has reached a certain minimum voltage.

The POR also serves to start the regulation of the oscillation frequency of the restlessness in a certain control state. If the Control by means of a counter in the comparator logic circuit 4 works, for example, by the POR or the counters are first placed in a certain state A, and then set and released in the state B on the disappearance of the POR.

Furthermore, the comparators 7, 8 (13, 14) for the rectifier 23 are switched with the POR in such a way that during the starting process the comparators 7, 8 (13, 14) are always switched on and work, and only with the disappearance of the POR The comparators are switched on and off at certain times in order to save electricity. It is also possible to operate in the start-up phase, only the comparators for the rectifier 23, and then turn on the other comparators 5, 11 as soon as they are needed in the further course of the start-up process.

The signal POR depends on the internal current source and the quartz oscillator 1 and, if desired, also on the voltage at at least one capacitance. As long as the current source does not supply enough power, a signal of a PORA is one, and as long as the frequency of the quartz oscillator does not reach a predetermined value, the signal of a PORB is also one. And as long as the voltage on a capacitance does not reach a desired value, the signal of the PORC is also one. The signal POR can be formed of PORA, PORB, PORC and signals from the frequency divider and the logic part of the electronic circuit; In addition, signals from the analog part of the electronic circuit can also be used. However, different PORs can also be formed from the signals described above.

Miniaturization of the electronic circuit

The electronic circuit is preferably designed so small that can be readily arranged in the movement under a bridge and hide.

Ideally, this happens by the restless bridge of a conventional mechanical movement together with the unrest and the Spiral spring is replaced. Now additionally the electronics 40 must be placed in the movement. It may be advantageous to place the electronics so that they are no longer visible, for example under the jam bridge. For this to be feasible, the electronics must be made as small as possible. Ideally, the electronic control circuit can even be integrated directly into the jitter bridge.

This can be realized by realizing the entire electric circuit 40 except the external capacitors and the external crystal 1 as an integrated electronic circuit 400. In order to save further space, the chip 40 is mounted directly with the flip-chip mounting technology, without further connecting wires, with the active contacting side facing downwards - to the substrate / circuit carrier. This leads to particularly small dimensions of the housing and short conductor lengths. Thus, the entire surface of the die (of the chip) can be used for contacting.

The dimensions of the individual commercially available components then have the following dimensions, for example: IC / chip 40 1x 1.52 x 1.03 x 0.4 mm Quartz 1 1x 2.0 x.0 x 0.6 mm capacitor 2x 1.0 x 0.5 x 0.5 mm capacitor 3x 0.4 x 0.2 x 0.2 mm

The elements are so small that they can be accommodated on a printed circuit board 400 of approx. 3.35 x 2.3mm, even if the elements are only mounted on one side. However, it would be possible to mount the elements on both sides of the printed circuit. Or it is also possible to use a flexible printed circuit and then bend the printed circuit so that capacitors come to lie on each other.

On such a small module but the space is very limited, it has practically only enough space for the electronic components. Test pads for debugging the electronic circuit can not be mounted on such a small circuit board. Also, arranging the conductor tracks for connecting the elements with each other is hardly possible. This problem can be solved by on the one hand the circuit board has on both sides strip conductors, which can also be interconnected through the circuit board. Thus, it is possible to solder a number of very small capacitors on top of the circuit board, but to arrange the electrical connections to the other elements on the underside of the circuit board. But this does not solve the problem of the test pads. This can be solved by placing the test pads 401 on an additional part of the circuit board 400 ( Fig. 3a, 3b ). This part of the circuit board 400 is disconnected after successful testing of the electronics. Thus, the test pads 401 can be generously designed, which facilitates testing later. But since this part is separated after successful testing, the final circuit board 400 has only very small dimensions.

Another way to save space is to make the circuit board 400 at least partially of flexible material. Thus, the terminals 300 for the piezospiral spring 20 may be configured as a thin long extension 402 of the circuit board 400. So it is no longer necessary to solder wires on the circuit board, which then produce the electrical connection to the piezospiral spring 20. The function of the wires takes over the thin, long extension of the flexible circuit board. This has the further advantage that after attaching the electronic components on the circuit board and the subsequent testing only the connection to the piezospiral spring 20 must be made. These are just two electrical connections that can be made with soldering or with electrically conductive glue. The electrical connection could also be made by bonding.

On the printed circuit 400, copper is provided under the IC 40 on both sides of the printed circuit. So no light penetrate through the printed circuit and affect the functioning of the IC.

Another possibility is the use of a multilayer, flexible circuit board 400, for example, with 3 layers. The electrical connection between the individual layers is produced by vertical contacts. On the top layer, the contacts to the IC, the capacitances, the quartz and the piezo spiked spring are applied. In the interlayer, the connections between the IC, quartz, capacitance and piezo-generator junctions are made, and the third layer can be used to form an opaque barrier under the IC. Thus, can be dispensed Lötstoplack, and the first and the third full-surface layer can first be nickel-plated and then gold-plated.

In order to ensure a safe functioning of the electronic circuit, the electronic circuit is coated after the separation of the test pads with a thin electrically insulating protective layer, for example with a paint which cures under UV light. This can be prevented that the electronic module makes an unwanted electrical contact with the movement or parts of the movement and is thus impaired in the function.

In this way, an electronic module with the smallest possible base area, but also with the smallest possible volume can be realized.

However, it is also conceivable not to separate the test pads 401 after testing out the electronics, but to fold the test pads in such a way that they take up only little space under the electronic circuit 400.

If the electronic circuit is bent then nickel should not be coated at this point. Nickel is too hard and the print could break at this point. With a three-layer flexible printed circuit can solve this problem by the electrical Connection to the piezoprial spring is realized by the middle layer or layer.

The entire electronics module is thus very small and can be easily hidden under a bridge or a similar component. This has the further advantage that the electronics are then protected from light, from electric fields and from magnetic fields. According to the invention, it would be advantageous to place the electronics under the balance bridge. Thus, an inventive movement looks like a purely mechanical movement, but has the advantage of much better accuracy.

Determining the control area

For the watchmaker can be helpful, the ability to display with the control electronics, if the frequency of the disturbance is no longer within the control range of the electronics. For example, if the disturbance oscillates too slowly, the electronics may indicate that the control range has been exhausted by changing the vibrational frequency of the crystal. This can be done by adding or removing internal capacitances of the integrated circuit 40 to the terminals of the crystal oscillator 1. Exactly the same can happen if the disturbance oscillates too fast and is no longer within the control range. For example, the frequency of the crystal oscillator can be increased if the disturbance oscillates too slowly and outside the control range of the electronics. Conversely, the frequency of the crystal oscillator can be slowed down if the noise oscillates too fast and outside the control range of the electronics. Thus, by simply measuring the frequency of the quartz oscillator, the watchmaker can determine if electronics can properly control the frequency of the disturbance.

Connection of the piezospiral spring 20 to the electronic circuit 40

The electrical connection 300 from the piezospiral spring 20 to the electronic circuit 40 must be designed such that it Connection is not mechanically stressed by the swinging of the restlessness.

This can be done, for example, by providing the end 30 of the coil spring 20 with a thickening 280. This thickening is then no longer subject to deformation when the rest swings back and forth and the coil spring is deformed. The mechanical fixation of the coil spring can also be realized at this thickening, be it by screws, clamps or gluing. And the electrical connection to the electronic circuit can be realized by soldering, gluing with an adhesive conductive adhesive or Adhesive Conduction Paste or by bonding; but it is also an electrical connection conceivable realized by mechanical means, for example by clamping.

Another possibility is to extend the coil spring 20 so that the end 280 of the piezospiral spring 30 protrudes beyond the blocks, so that the electrical connection 300 between the piezospiral spring 20 and the electronic circuit 40 can be made at the mechanically unloaded end. This can be done with soldering, for example, if the Curie temperature of the piezoelectric material is not exceeded.

Another variant is to make the blocks so that in the front region of the piezo-helical spring 20 is mechanically held and absorbs the vibrations, and in the rear region of the electrical contact between the electrodes of the piezoelectric material and the electronic circuit 40 is made. The electrodes can be applied to the piezo material by CVD (Chemical Vapor Deposition) process. Alternatively, the electrodes may be applied by sputtering or by a galvanic process.

In a movement according to the invention, all the complications already known for mechanical watches, such as automatic winding, date, moon phase, chronograph, etc., can be realized. The difference to the conventional mechanical movement is only in the Realization of the scheme. All other components are identical to a mechanical clock.

The inventive movement can be designed so that the end customer can choose whether he wants to have a conventional, mechanical restlessness or an additionally electronically controlled restlessness. In this case, the restlessness and the spiral spring of the inventive movement will be designed differently, anchor, escape wheel can remain the same, although they may also be changed. The bearings are the same. The electronics can be integrated, for example, in the balance bridge. This ensures that the watch's plate is the same for both types of watches, whether purely mechanical or electronically controlled. In this way, a higher added value can be generated with the same amount of capital.

Merging of balance and piezospiral spring

Because they are made separately, the balance and coil spring must be matched. It is very important to make the spiral and balance precisely so that the moment of inertia of the balance and the moment of the coil spring can be balanced.

This method consists in bringing together a balance with the appropriate coil spring. The riots, already balanced, are divided into several, for example twenty, classes according to their moment of inertia.

The piezospiral springs are also classified according to their respective moment in several, for example twenty, classes.

The riots and spiral springs so divided can now be assigned to each other according to their classes.

Since the oscillation frequency of the restlessness can be changed by means of the control electronics in a range of about 1%, it is in the careful measurement of restlessness and piezospiral and the subsequent assembly possible to regulate the exact oscillation frequency of restlessness only with the small auxiliary electronics. Ideally, the watchmaker has nothing to do with the regulator.

It is also useful not only to measure the mechanical properties of the piezospiral spring, but also the electrical properties such as the induced voltage as a function of the amplitude of the restlessness, the internal resistance of the piezospiral spring and the electrical capacity of the piezospiral. So mechanically faultless, electrically but defective coil springs can be sorted out.

Claims (22)

1. Method for controlling the oscillation frequency of a piezoelectric balance-spring (20) in a clockwork, characterized in that the oscillation frequency of the piezoelectric balance-spring is controlled by adjusting a capacitor (22) connected in parallel with the balance-spring.
2. Method according to claim 1, characterized in that said capacitance (22) consists of a number of capacitors (222, 224, 226, 228) which can be activated or deactivated.
3. Method according to claim 2, characterized in that the oscillation frequency is controlled by individual activating or deactivating of the individual capacitors (222, 224, 226, 228).
4. Method according to claim 3, characterized in that the combination of the capacitors to be activated is determined by the magnitude of the phase shift between the frequency of the balance (30) and a reference frequency.
5. Method according to one of the claims 1 to 4, characterized in that the capacitors (222, 224, 226, 228) are activated only when the voltage induced by the balance-spring (20) is lower than a predetermined threshold.
6. Method according to one of the claims 1 to 4, characterized in that the capacitors (222, 224, 226, 228) are activated only when the current generated by the balance-spring is lower than a predetermined threshold.
7. Method according to one of the claims 1 to 6, characterized in that each capacitor (222, 224, 226, 228) is activated individually via a single switch (221, 223, 225, 227).
8. Method according to claim 7, characterized in that the control voltage of said switches is approximately equal to the voltage to be switched.
9. Method according to one of the claims 7 to 8, characterized in that said switches (221, 223, 225, 227) are switched via a level shifter (9).
10. Method according to one of claims 7 to 9, characterized in that said switches are controlled by an electronic circuit, the control voltage (V_dc) of said switches (221, 223, 225, 227) being higher than the supply voltage (V_dd) of most digital components in the electronic circuit.
11. Method according to one of the claims 1 to 10, characterized in that a capacitor (21) is connected in parallel with the piezoelectric balance-spring (20) permanently, so that the output voltage of the piezoelectric balance-spring (20) is in a predetermined range.
12. Method according to one of the claims 1 to 11, characterized in that the voltage induced by the spiral (20) is rectified by a rectifier (23), in that said rectifier comprises diodes which, after starting, are replaced by switches (230 'to 233'), and in that the control voltage of said switches of the rectifier is approximately equal to the rectified voltage.
13. Method according to one of the claims 1 to 12, characterized in that the voltage induced by the spiral is rectified by a rectifier (23), in that said rectifier comprises diodes which, after starting, are replaced by switches (230 'to 233'), and in that said switches of the rectifier are switched via a level shifter (10).
14. Method according to one of the claims 1 to 13, wherein one input of a comparator logic circuit (4) is connected to an electronic reference circuit (1, 2), another input of the comparator logic circuit is connected to the piezoelectric balance- spring (20), wherein the comparator logic circuit compares a clock signal from the electronic reference circuit with a clock signal from the balance-spring and, depending on the result of this comparison, controls the magnitude of the impedance of the electronic control circuit (22) over the number of parallel capacitors (222, 224, 226, 228) connected in parallel to the piezoelectric balance-spring, and in this way adjusts the running of the time display by controlling the impedance, wherein at least one comparator (5) is turned off during each period.
15. Method according to one of claims 1 to 12, characterized in that when starting the electronic circuit by a power on reset POR signal, a certain combination of capacitors (222, 224, 226, 228) is connected in parallel to the piezoelectric balance-spring (20), in order to achieve advantageous induced voltage of the piezoelectric balance-spring for starting the electronic circuit.
16. Method according to one of the claims 4 to 15, wherein said phase shift is determined on the basis of a first large counter and of a second small counter.
17. Method according to one of the claims 1 to 16, characterized in that the counter value is buffered at the output of the small counter after the arrival of a down-pulse and used later to activate or deactivate said capacity.
18. Control element for a watch movement, comprising the following components:

    a balance (30) oscillating at an oscillating frequency around a balance staff;

    a piezoelectric balance-spring (20) connected with the balance, which generates a voltage dependent on the oscillations of the balance and of the balance-spring;

    an electronic circuit as an auxiliary control element, for adjusting the rigidity of the piezoelectric balance-spring (20) to control the oscillating frequency of the balance;

    characterized in that the electronic circuit comprises at least one capacity connected in parallel to the balance-spring (20) for adjusting the oscillating frequency of the piezoelectric balance-spring.
19. Control element according to claim 18, characterized in that the capacitor has a plurality of individually switchable capacitors (222, 224, 226, 228).
20. Control element according to one of the claims 18 or 19, wherein the auxiliary control element comprises a rectifier circuit (23) for rectifying the voltage generated by the balance-spring, wherein at least a first capacitive component is charged at least immediately after a first start of the movement via a passive component or passive components, and the passive component or the passive components are replaced by an active unit, as soon as the voltage of the first capacitive component is sufficient for operating the active unit, wherein the active unit has, in the forward direction, a lower electrical resistance than the passive component.
21. Control element according to one of the claims 19 or 20, characterized by:

    switches (221, 223, 225, 227) for activating said capacitors;

    a level shifter (9) for controlling said switches with an increased voltage.
22. Control element according to one of the claims 18 to 21, characterized by a flexible printed circuit board for connecting the piezoelectric balance-spring (20) to the electronic circuit (40).

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