HK1143867B - A time base device for a watch - Google Patents

Description

Time base unit for a watch

Technical Field

The invention relates to a time base device for a timepiece, in particular an electronic timepiece. The time base unit has at least one electric motor coil which can be used to drive an analog display device, a module having at least one time base oscillator circuit mounted in a module housing, and an electric power source.

Background

It is known in the art to use an oscillator coupled to a quartz resonator to manufacture a time base device for a clock movement. Such a time base unit also comprises a frequency divider for dividing the oscillator frequency and a control circuit for an electric motor connected to the frequency divider. The electric motor is controlled by a control circuit to drive in particular the hands of a time display, for example on a dial.

Each component of the time base unit is usually fixed to at least one printed circuit board, on which an electrical connection is formed between the electronic components of the time base unit. The printed circuit board comprising said time base unit may also be connected to a watch movement. These various elements are also powered by a voltage source, for example a battery or accumulator, which may be mounted in a housing provided therefor, which is connected to the printed circuit board. The assembly of all these time base unit electronics therefore occupies a relatively large volume, which is a drawback for assembly or integration in small-sized clocks.

In order to reduce the bulk of the electronic component assembly of the time base device, it is known to use a quartz resonator (in the form of a tuning fork associated with an oscillator) to form part of the time base. The tuning fork quartz resonator and the integrated circuit comprising the oscillator may be grouped together in the same housing.

It is known to group various electronic components within the same housing, in particular as known from us patent No.3,784,725. In this document, the electronic components for the watch form a single unit. The electronic components of the assembly are usually mounted separately and connected to the printed circuit board, which causes problems and costs for mounting in watch cases of small dimensions. However, such electronic assemblies combine all of the electronic components with the watch bezel to facilitate mounting the assembly within a conventional watch movement, plastic watch case, or jewelry piece.

Although the prior art solutions can partially reduce the volume specifically occupied by some of the components of the time base, the available space is still insufficient to allow a timepiece of small size. The need to mount multiple integrated circuits on one or more printed circuit boards in order to perform multiple watch functions means that a large amount of space is occupied within the watch. This requires an extreme increase in the volume of the watch, which is undesirable.

Disclosure of Invention

It is therefore a main object of the present invention to overcome the above drawbacks by providing a time base unit for a watch which is compact and easy to carry out the assembly operations inside a small-sized watch case.

The invention relates to a time base unit for a watch, comprising at least one coil of an electric motor, an electronic module with at least one time base oscillation circuit mounted in a housing of said module, and a power voltage source, said time base unit being characterized in that said coil, said electronic module with oscillation circuit and said voltage source are mechanically and electrically connected to each other to form a compact unit without the use of a printed circuit board.

Particular embodiments of the time base unit are defined in the dependent claims 2-11.

One advantage of the time base unit according to the invention lies in the fact that: the electrical connection between the voltage source (which may be a battery or an accumulator) and the electronic time base module and between the motor coil and said electronic module is realized without the use of printed circuit boards. The metal flanges connect the battery positive and negative poles to two external connection terminals of the module, and the two metal wires of the coil winding are directly connected to the other two external connection terminals of the module. In the case of a two-phase motor, it is advantageous if the three metal coil wires are connected directly to the three external connection terminals of the module.

Since the electronic module advantageously accommodates the oscillator (e.g. quartz oscillator), the frequency divider and the motor control circuit within the same housing, only 4 or 5 electrical connection terminals are required on the outer surface of the module housing. The oscillator, frequency divider and control circuit may form a single integrated circuit. This reduces the bulk of all the elements of the time base unit, i.e. it reduces the bulk of the watch movement by moving the motor closer to the battery.

Grouping the various elements of the time base unit together in a reduced space also reduces the connection length between the electronic components of the unit and also reduces the sensitivity of the oscillator to external disturbances. This also eliminates some mechanical operations for assembling the electronic components, which reduces the production costs of the movement equipped with the time base unit according to the invention.

Drawings

Objects, advantages and features of a time base unit for a watch may be apparent in the following description, made in a non-limiting manner with reference to the accompanying drawings, in which:

figure 1 shows a schematic view of an electronic watch with an analog display, comprising a time base unit according to the invention;

fig. 2 shows a three-dimensional view of various elements of a time base unit according to the invention;

FIG. 3 shows a partial longitudinal cross-sectional view of an electronic module of a time base unit according to the invention; and

fig. 4 is a partial top view of an electronic module of a time base unit according to the invention.

Detailed Description

In the following description, only those elements of all time base units for electronic watches which are already known to those skilled in the art are mentioned in a simplified manner.

Fig. 1 schematically shows the components of an electronic watch comprising a time base unit according to the invention. The meter has a voltage source 8, for example a battery or accumulator, to power the electronic module 1, the electronic module 1 having a time base and means for controlling the electric motor 6. The electric motor is controlled to drive a gear train (not shown) to rotate an analog display device, such as a pointer 9, for example, indicating time.

The time base unit is essentially formed by the voltage source 8, the electronic module 1 and the at least one coil of the electric motor 6. As described below with reference to fig. 2, these time base unit elements are advantageously mechanically and electrically connected to form a compact unit of small size without the use of a printed circuit board.

In one case, the electronic module 1 comprises an oscillator 3, which oscillator 3 may be an oscillator with, for example, a piezoelectric resonator 2 (such as a quartz resonator) or even a silicon MEMS resonator connected to the terminals of the oscillator 3. The electronic module 1 further comprises a frequency divider 4 to obtain the required operating frequency for the watch to indicate the correct time, wherein an input of the frequency divider 4 is connected to an output of the oscillator 3. The output of the frequency divider 4 is connected to a control circuit 5 of an electric motor 6 for driving a pointer 9. The oscillator 3 with the resonator 2 and the frequency divider 4 may form part of a time base oscillator circuit.

A Lavet type stepping motor may be used as the electric motor 6, which electric motor 6 may also be called a bipolar motor, which is formed by a magnetized rotor, a stator having a large magnetic permeability to form a magnetic circuit loop, and at least one coil. The coil acts to generate a magnetic field in the stator when the coil is in operation, whereby the stator transforms into a magnet, wherein the polarity of the magnet depends on the direction of current in the coil. Thus, the control circuit 5 of the motor 6 supplies the current flowing in the coil. The motor is controlled by a series of positive and negative pulses separated by a current interrupt. However, other types of motors, such as a two-phase stepper motor, may be used to obtain a bi-directional motor capable of setting the time of the schedule forward and backward. In the case of a two-phase motor, three motor outputs need to be provided on the electronic module 1.

Advantageously, as shown in fig. 1, the oscillator 3, the frequency divider 4 and the electric motor control circuit 5 together form part of a single integrated circuit 7. This reduces the space occupied by these electronic components in the electronic module 1 and, in particular, reduces electromagnetic interference with the electronic components due to the length of the wiring connections between the components.

As shown in fig. 2 to 4, and all the above elements are grouped in an electronic module 1, said electronic module 1 having only four or five external connection terminals, instead of eight terminals as is usual. In practice, two connection terminals are usually provided for exciting the resonator 2, two further terminals are provided for connecting to the integrated circuit 7, two further terminals are provided for powering the integrated circuit, and finally two further terminals are provided for controlling the motor. In the electronic module 1, four terminals or five terminals are shown in the figure as having to be on the outside of the housing, i.e. two terminals for powering the integrated circuit and two or three terminals for connecting to the integrated circuit for controlling the motor. The other terminals are arranged only inside the housing of the electronic module 1.

Fig. 2 shows a three-dimensional view of a time base unit according to the invention. Like reference numerals are used to refer to like elements described with reference to fig. 1. This time base unit therefore comprises a voltage source 8, the electronic module 1 and an electric motor coil 30, the voltage source 8 preferably being a battery.

The electronic module 1, which is accommodated in a housing, in particular a ceramic housing, comprises an oscillator and a resonator, a frequency divider and an electric motor control circuit. As mentioned above, the oscillator, frequency divider and control circuit may form a single integrated single circuit, although it is of course conceivable that these elements could be fabricated on more than one integrated circuit if necessary.

Four connection terminals 14, 15, 16 and 17 are provided on the outer surface of the electronic module 1. As described with reference to fig. 3 and 4, these connection terminals are provided on the outer surface of one wall of the housing. An integrated circuit and conductive connection paths connecting the integrated circuit to the resonator and the connection terminals are mounted on the inner surface of the wall. The four connection terminals shown are preferably disposed at four corners of the outer surface, respectively. These connection terminals on the outer surface are advantageously used as a base for connecting other elements of the time base unit. This simplifies the assembly of the time base device elements of the watch movement and also greatly reduces the bulk of the assembly by reducing the number of parts.

This electronic module 1 can be housed in a substantially parallelepiped-shaped receptacle 10, which receptacle 10 is open on one or both faces. The receiving member 10 may be defined in whole or in part as a metal or plastic plate, or may form part of an integral watch movement. In the example shown in fig. 2, the receiving member 10 is open on both surfaces.

Once the electronic module 1 has been fixed in the receiver, for example by gluing, four or five connection terminals of the electronic module can be reached from the open top surface of the receiver. Preferably, the outer surface of the module 1, where the connection terminals 14, 15, 16 and 17 are located, is arranged at the same level as the mouth of the open top surface of the receiver 10, in particular at the top edge of the vertical receiver wall. This facilitates the electrical and mechanical connection of the other elements of the time base unit.

The two first connection terminals 14 and 15 of the outer surface of the module are intended to be electrically connected to the two positive and negative poles of a voltage source 8, here the voltage source 8 preferably being a battery, via two conventional metal flanges 24 and 25, respectively. The first flange 24 is fixed or welded to one of the first metal connection terminals 14 to connect the positive electrode of the battery, and the second flange 25 around the outside of the receiving member 10 is fixed or welded to the other first metal connection terminal 15 to connect the negative electrode of the battery.

The two second connection terminals 16 and 17 of the outer surface of the module are connected to the conventional windings of the electric motor coil 30, wherein said two second connection terminals 16 and 17 are arranged on opposite sides of the two first terminals 14 and 15. The first metal wire 31 of the coil 30 is soldered to one of the second metal connection terminals 16, and the second metal wire 32 of the coil 30 is soldered to the other second metal connection terminal 17. The core of the coil 30, which is part of the magnetic circuit 33, can be fixed to another, not shown, part of the magnetic circuit of the electric motor, for example by means of screws provided for this purpose through two holes.

The skilled person will also appreciate that the receiving part 10 of the electronic module 1 can be used as a support for the motor coil 30 in case of using all its mechanisms. This coil may also be directly fixed to the edge of the opening side surface of the receiving member 10. The battery attachment flanges 24 and 25 may be integrally formed into a housing that receives a battery (not shown). This housing may form part of the receiving member 10 or be fixed to a side wall of the receiving member.

The arrangement of all components, for example inside a ceramic housing of an electronic module, is now explained with reference to fig. 3 and 4. Like reference numerals are used to refer to like elements described with reference to fig. 1 and 2.

Fig. 3 is a central and longitudinal cross section of the electronic module 1 of the time base unit. Inside the housing 11 of the module, the resonator 2 is fixed by soldering or gluing with a conductive adhesive the connection pads of the two sets of electrodes located on the base of the resonator to the corresponding conductive paths 18 provided on a step 19 at the bottom of the housing 11. This allows the resonator 2 to be located above the integrated circuit 7 disposed on the inner surface of the bottom wall of the housing 11.

The connection between the connection pads on the base of the resonator 2 and the integrated circuit 7 for exciting the electrodes and vibrating the resonator can be realized by means of the conductive pads 18 connected to the holes 22. These holes 22 are formed in the step 19 and filled with a suitable conductive material and are connected to conductive paths provided on the inner surface of the bottom wall of the housing. These conductive paths are in turn connected to corresponding contact pads of the integrated circuit 7.

The integrated circuit 7 may be connected to the connection terminals 14, 15, 16 and 17 outside the housing, these terminals 14, 15, 16 and 17 being provided on the outer surface of the bottom wall of the housing, as described above. For this purpose, in this example, the connection studs 12 are provided on the inner surface of the bottom wall, advantageously below the integrated circuit 7. These connection studs or connection bumps 12 are arranged in the same way as the contact pads of the integrated circuit 7, so that they can be electrically connected to said contact pads of the integrated circuit by means of flip-chip technology. Some of the integrated circuit contact pads are thus electrically connected by conductive paths to the external connection terminals 14, 15, 16 and 17 by means of holes 20 through the bottom wall of the housing 11, wherein said holes 20 are filled with a conductive adhesive 21 or any other suitable conductive material. Since these holes are disposed opposite to the connection terminals 14, 15, 16, and 17, the conductive adhesive 21 provides electrical connection with the inside of the housing.

Fig. 4 is a top view of the electronic module 1 of the time base unit without the sealing cover. For the sake of simplicity, the resonator inside the casing, which may be made of ceramic material and is substantially parallelepiped-shaped, is not shown. A cover (not shown) hermetically sealing the housing may advantageously be made of glass to allow for precise laser tuning of the resonator frequency.

Inside the housing 11 of the electronic module 1, the integrated circuit 7 is fixed via contact pads 13 (shown in dashed lines) to connection bumps (not shown) provided on the inner surface of the bottom wall of the housing. As mentioned above, the arrangement of the contact bumps is the same as the arrangement of the contact pads 13, so that the integrated circuit can be fixed by flip-chip technology. The integrated circuit 7 comprises an oscillator, a frequency divider and an electric motor control circuit.

Resonator electrodes (not shown) are soldered to the conductive pads 18 connected to the holes 22. These holes 22 are formed in the step 19 and filled with a suitable conductive material, such as a conductive adhesive or metal. Thus, the conductive pad 18 is connected to a conductive path 23, which conductive path 23 is provided on the inner surface of the bottom wall of the housing. These conductive paths 23 connect the conductive pads 18 to some of the contact pads 13 of the integrated circuit 7 and also connect some other conductive pads 13 of the integrated circuit 7 to the external connection terminals 14, 15, 16 and 17.

The integrated circuit 7 is electrically connected to the external connection terminals by means of holes 20 through the bottom wall of the housing 11. These holes 20 are filled with a conductive adhesive 21 or any other suitable conductive material. Since the holes are disposed opposite to the connection terminals 14, 15, 16, and 17, the conductive adhesive 21 provides electrical connection with the electronic components inside the housing. The two first external connection terminals 14, 15 are connected to a voltage source, for example a battery, for powering the integrated circuit 7. Two second external connection terminals 16 and 17 are connected to the windings of the electric motor coil to provide positive and negative electric pulses.

Due to the arrangement of the integrated circuit 7 (the resonator connected to the inside of the housing), the space occupied by all these elements is optimized. Furthermore, the integrated circuit 7 is protected from any external disturbances, also due to the relatively short connection paths between the components.

Given the description that has just been given, a person skilled in the art will be able to derive numerous variants of a compact time base unit without departing from the scope of the invention as defined by the claims. Multiple electric motors may be connected across the same connection terminals or across different connection terminals of the electronic module. The timing of the start of each motor connected to the electronic module may be different. The electronic module may be connected to the voltage source and to the coil without being disposed within the receiving member. The voltage source that powers the electronic module may be formed in part as a combination of a solar cell and a battery or accumulator.

Claims (13)

1. Time base unit for a watch, comprising at least one coil (30) of an electric motor (6), an electronic module (1) having at least one time base oscillation circuit (2, 3, 4) mounted within a casing (11) of said electronic module, and a power voltage source (8), characterized in that: two contact flanges (24, 25) connect the positive and negative poles of a source of electric power voltage (8) to two first external connection terminals (14, 15) of the electronic module, at least two metal wires (31, 32) of the winding of the electric motor coil (30) being directly connected to at least two second external connection terminals (16, 17) of the electronic module, said coil (30), said electronic module (1) with oscillating circuit and said source of electric power voltage being mechanically and electrically connected to each other so as to form a compact unit.

2. The time base unit of claim 1, wherein: the electronic module (1) comprises, within the housing: an oscillator (3), a frequency divider (4) and a control circuit (5) for an electric motor (6), the oscillator and the frequency divider forming the time-based oscillation circuit, which is powered by the electric voltage source from outside the housing.

3. The time base unit according to claim 2, characterized in that: the oscillator (3) is connected to the inside of the housing, to the piezoelectric resonator (2); and the piezoelectric resonator, the frequency divider and the control circuit for the electric motor are made in a single integrated circuit (7).

4. The time base circuit according to claim 2, characterized in that: the oscillator, the frequency divider and the control circuit for the electric motor are manufactured in a plurality of integrated circuits (7).

5. Time base unit according to claim 3, characterized in that: -contact pads (13) of the integrated circuit (7) are connected to conductive bumps (12), the conductive bumps (12) having the same arrangement as the contact pads, the conductive bumps (12) being arranged on the inner surface of the bottom wall of the housing of the electronic module (1): and a conductive path (23) connecting a conductive bump on the inner surface of the bottom wall to the piezoelectric resonator (2) and to the at least four external connection terminals (14, 15, 16, 17) provided outside the module case (11).

6. Time base unit according to claim 5, characterized in that: a conductive path (23) connecting the at least four external connection terminals (14, 15, 16, 17) by means of a conductive hole (20) penetrating the bottom wall of the housing; and said at least four external connection terminals are arranged at four corners of said external rectangular surface, connected to said electric power voltage source by means of two contact flanges (24, 25), and connected on opposite sides to at least two metal wires (31, 32) of a winding of said electric motor coil (30), and said control circuit (5) in said housing controls said electric motor to drive an analog display device.

7. The time base unit of claim 6, wherein: the electronic module (1) comprises three second external connection terminals respectively connected to three metal wires of at least one winding of a two-phase motor coil (30), which is an electric motor coil.

8. The time base unit of claim 1, wherein: the electronic module (1) is housed inside a receiving element (10), the receiving element (10) being open at least on the top surface; and the electronic module (1) comprises said at least four external connection terminals (14, 15, 16, 17) arranged at the four corners of the external rectangular surface of the bottom wall of the housing (11), the electronic module being arranged within the receptacle such that the at least four external connection terminals are accessible through the open top surface of the receptacle (10).

9. The time base unit of claim 8, wherein: the outer surface of the electronic module (1) where the at least four external connection terminals (14, 15, 16, 17) are located is arranged at the same level as the mouth of the open top surface of the receiving part (10).

10. The time base unit of claim 9, wherein: the coil (30) and/or the electric voltage source are fixed to the receiving member (10) as a support so as to define a compact unit.

11. The time base unit of claim 9, wherein: the receiving part (10) forms part of a watch movement.

12. Time base unit according to claim 3, characterized in that: the piezoelectric resonator (2) is a quartz resonator or a silicon MEMS resonator.

13. The time base unit of claim 9, wherein: the receiving element (10) forms part of a watch.