HK1194541B - Electronic quartz resonator module provided with shock resistant securing means - Google Patents

Description

Electronic quartz resonator module provided with impact-resistant fixing device

Technical Field

The invention relates to an electronic module with a quartz or MEMS resonator, which is provided with an impact-resistant fastening means. The quartz or MEMS resonator is confined within a resonator housing provided on at least one of its outer surfaces with electrical contact pads for electrical connection of the resonator. The printed circuit board carries the resonator case and comprises electrical connection terminals for connection to the electrical contact pads of the resonator case.

Background

SMD quartz clock resonators are generally mounted directly on a printed circuit board so as to be rigidly fixed to the clock movement of the watch. When the watch is subjected to mechanical shocks, the quartz resonator in its case may be damaged by the mechanical shocks transmitted directly to the resonator. Therefore, the efficiency of the quartz resonator may be reduced and thus poor operation accuracy may result. This risk is greater for high accuracy tables with temperature compensation. A watch provided with a quartz resonator of this type rigidly fixed in the watch movement is prone to loss of accuracy after being merely dropped on a hard floor, which is a drawback.

CN patent application No.201699667U discloses a module provided with a plug-in quartz resonator. In order to accommodate the quartz resonator, the module comprises a metal cover and a base on which the quartz resonator is mounted. The quartz resonator is electrically connected by two conductive flanges to pins protruding from the housing for electrical connection of the module. These conductive flanges provide some elasticity to protect the quartz resonator from any mechanical impact on the module. However, this module cannot be simply integrated in a watch case having small dimensions and does not guarantee a proper protection of the quartz resonator when the watch housing the electronic module is subjected to mechanical shocks, which is a drawback.

The CH patent No.609528B discloses a quartz resonator enclosed in a metal housing. A frame in the form of a spring rod holds and electrically connects the resonator within the housing for electrical connection to the exterior of the housing. The metal fastening frame provides the resonator with resistance to mechanical shocks, but the fastening frame is in direct mechanical and electrical contact with the quartz resonator inside the housing, which does not provide adequate resistance to repeated shocks. This therefore constitutes a drawback.

US patent application No.2007/0035214 discloses a piezoelectric oscillator. The oscillator includes a piezoelectric resonator confined within a resonator housing. The resonator housing is fixed on the base of the housing structure via elastic damping elements as impact-resistant fixing means. The resonator housing may also be fixed in the oscillator housing structure by being sandwiched between the damping elements. However, it is a drawback that the resonator housing is not sufficiently held in the oscillator housing structure to ensure a suitable impact-resistant fixture.

Disclosure of Invention

The main object of the present invention is therefore to overcome the above drawbacks by proposing an electronic module with a quartz or MEMS resonator, provided with a new type of shock-resistant fixing means and capable of being installed in a watch, such as a wristwatch.

The invention therefore relates to an electronic module with a quartz or MEMS resonator, which comprises the features of independent claim 1.

Dependent claims 2 to 12 define specific embodiments of the electronic module.

One advantage of the electronic module with a quartz or MEMS resonator of the invention is that the damping element, preferably an elastomeric element, fixedly holds the housing containing the quartz or MEMS resonator in the electronic module housing structure. When the electronic module is mounted in the watch close to the movement, any impact sustained by the watch is transmitted to the resonator inside its case, which is greatly reduced by the fixing means formed by the elastomer element. This protects the resonator from any mechanical shock and reduces any risk of the resonator losing accuracy or being damaged.

Advantageously, two damping elements are provided on both sides of the resonator housing to hold it in the electronic module housing structure. The two damping elements may be elastomeric elements that may be compressed between two inner walls of the electronic module housing structure. One of the elastomeric elements may be disposed between the printed circuit board and the resonator housing. The elastomeric element may further comprise wires for connecting the electrical connection terminals of the printed circuit board to the electrical contact pads of the resonator housing.

Drawings

The objects, advantages and features of the electronic quartz or MEMS resonator module can be more clearly seen from the following non-limiting description with reference to the attached drawings, in which:

figure 1 shows a cross-sectional view of a housing containing a quartz resonator for an electronic module according to the invention.

FIG. 2 shows a partial schematic view of a partial cross-section of a first embodiment of an electronic module according to the invention with a quartz or MEMS resonator, and

fig. 3 shows a partial schematic view of a partial cross-section of a second embodiment of an electronic module according to the invention with a quartz or MEMS resonator.

Detailed Description

In the following description, all those components of the electronic module with a quartz or MEMS resonator of the invention which are known to the person skilled in the art are described in a simple manner only. The following description is primarily based on the way in which a quartz or MEMS resonator housing is fixed within the housing structure of an electronic module by impact-resistant fixing means.

Fig. 1 shows a quartz or MEMS resonator component 2 in general terms. The member 2 comprises, for example, a quartz resonator 3 placed in a resonator housing 5, which resonator housing 5 is sealed by a cover 5'. The resonator housing may be made of a metal or a ceramic material. The clock integrated circuit 4 connected to the quartz resonator 3 can also be placed in a sealed resonator housing in a known manner. Electrical contact pads 15 are provided on at least one outer surface of the resonator case 5 for electrically connecting the quartz resonator 3 or the resonator to the watch integrated circuit 4. For example, two, four or eight metal electrical contact pads may be provided at the four corners of the rectangular outer surface of the resonator case 5.

Quartz resonator components such as MicroCrystal CM7 or MicroCrystal WM-1322-C7 or WM-1323-C7 can be used in electronic modules. However, other types of quartz or MEMS resonator components may also be used in the electronic module. The dimensions of this type of quartz resonator member may be 3 to 4mm long, 1.5 to 2mm wide and less than 1mm thick.

Fig. 2 is a schematic view of a first embodiment of an electronic module 1 with a quartz or MEMS resonator. The illustration of the various elements in fig. 2 does not reflect their actual dimensions. The quartz or MEMS resonator component 2 is fixedly held in the housing structure of the electronic module 1 via at least one damping element 7. The damping element may be made of an elastomer for protecting the quartz or MEMS resonator in the resonator housing 5 from any mechanical impact on the electronic module. The quartz or MEMS resonator member 2 is also mounted on the printed circuit board 6. The member 2 is preferably mounted on a rigid printed circuit board 6 via said elastomer element 7.

The electrical connection terminals 18 of said printed circuit board 6 are arranged to be electrically connected to the electrical contact pads 15 of the resonator case 5. The printed circuit board 6 also includes a metal via structure (not shown). The first damping element 7 is an elastomeric element comprising conductive wires 17 in an elastomeric material, which wires 17 are used to connect the electrical contact pads 15 of the resonator housing 5 to electrical connection terminals 18 of the printed circuit board 6. The electrical connection between the connection terminal 18 and the contact piece 15 via the lead 17 can be simply achieved by contact by pressing the elastomer element 7 or by retention using a conductive adhesive.

The first elastomeric element 7 is a "zebra" connector. Preferably, the first elastomeric element 7 comprises a plurality of rows of regularly spaced metal wires 17, which pass right through the thickness of said first elastomeric element. The first elastomer element, for example the silicon elastomer element 7, may be of the GB-Matrix type manufactured by Shin-Etsu company. It may have a thickness between 0.3 and 2.5mm and a length and width comparable to the quartz or MEMS resonator housing 5 used.

Preferably, the resonator housing 5 is fixedly held in the housing structure of the electronic module 1, sandwiched between two damping elements 7, 8, which damping elements 7, 8 may be elastomeric elements of the same or different types. Only the first elastomeric element is provided with wires 17. The first elastomeric element 7 may be in contact with the entire lower surface of the resonator housing 5, while the second elastomeric element 8 may be in contact with the entire upper surface of the resonator housing 5. The elastomer elements 7 and 8 may also extend on each side of the support surface of the resonator housing 5. Said damping elastomer element keeps the resonator housing 5 compressed between two walls or inner surfaces of the housing structure of the electronic module 1. Two elastomer elements may also be bonded to the upper and lower surfaces of the resonator housing 5.

In this first embodiment, the housing structure of the electronic module 1 comprises a base formed by the printed circuit board 6. The printed circuit board is preferably rigid. The housing structure of the electronic module 1 further comprises a rigid cover 9, which is glued or soldered to the printed circuit board to confine the resonator housing 5 in at least the first cavity. The cover may be made of opaque plastic or metal. The resonator housing 5 is fixedly held in this housing structure of the electronic module 1, sandwiched between two damping elements 7 and 8. Once the cover 9 is fixed on the printed circuit board, the two elastomeric elements 7 and 8 may fixedly hold the resonator housing 5 by squeezing the resonator housing 5 between the inner surface of the cover 9 and the inner surface of the printed circuit board 6.

The printed circuit board 6 may also include one or more other electronic components, such as an integrated circuit 14, on the same electrical connection surface. The integrated circuit 14 can be used, for example, for controlling the signals provided by the resonators coupled to the clock circuit and for storing various data. The integrated circuit 14 may be located in the second cavity of the lid 9. Although not shown in fig. 2, the printed circuit board 6 may also include external connection terminals that are accessible outside the housing structure of the electronic module 1.

Fig. 3 is a schematic view of a second embodiment of an electronic module 1 with a quartz or MEMS resonator. The quartz or MEMS resonator component 2 is mounted directly on a printed circuit board 6, which printed circuit board 6 is preferably flexible. The electrical contact pads 15 of the resonator case 5 are soldered directly to the electrical connection terminals 18 of the flexible printed circuit board 6. The resonator housing 5, which is fixed to the printed circuit board 6, is also fixedly held in the housing structure of the electronic module 1 via at least one damping element 7.

The first damping element 7 may be an elastomeric element as described in the first embodiment. However, with this second embodiment, the first elastomer element does not have any wires for connecting the contact pieces 15 to the connection terminals 18, since the resonator member 2 is directly fixed on the printed circuit board 6. Preferably, the resonator housing 5 fixed on the flexible printed circuit board 6 is fixedly held in the housing structure of the electronic module 1, sandwiched between two damping elements 7 and 8. The two damping elements may be elastomeric elements.

The first elastomeric element 7 is in contact with the inner surface of a rigid base 10 of the housing structure and the second elastomeric element 8 is in contact with the inner surface of a rigid opaque cover 9 of the housing structure. The cover 9 is bonded or welded to the base 10. When the cover 9 is fixed to the base, the two elastomeric elements 7 and 8 may be compressed in order to keep the resonator case 5 fixedly housed in the first cavity of the cover 9.

The flexible printed circuit board 6 may carry further electronic components arranged in the second cavity of the cover 9. The metal via structures (not shown) of the printed circuit board 6 are provided for electrical connection of said electronic components, such as the integrated circuit 14. However, other electronic components may be mounted on another rigid printed circuit board 16, which rigid printed circuit board 16 is directly mechanically and electrically connected to the flexible printed circuit board 6. The connecting portions of the two printed circuit boards 6, 16 can be arranged in suitably dimensioned channels between the two cavities of the housing structure. This restricts the movement of the connecting portions of the two printed circuit boards within the housing structure of the electronic module 1.

It is noted that the two printed circuit boards 6 and 16 may form a single component, but the flexible portion has a much smaller thickness.

From the description just given, a person skilled in the art can devise many variants of an electronic quartz or MEMS resonator module without departing from the scope of the invention as defined by the claims. A damping element, such as an elastomeric element, may be provided on the side of the resonator housing. The resonator housing can be fixed on the flexible printed circuit board and held on the housing structure of the electronic module by means of damping elements fixed on the sides of the resonator. A metal spring flange or any other elastic element capable of damping mechanical shocks to the electronic module may also be used as a damping element. The resonator case may also be fixed to the printed circuit board by a flexible conductive resin adhesive.

Claims (8)

1. An electronic module (1) with a quartz resonator or a MEMS resonator, comprising:

-a quartz resonator or a MEMS resonator confined within a resonator housing (5) provided with electrical contact pads (15) on at least one outer surface of said resonator housing, said electrical contact pads (15) being used for electrical connection of said quartz resonator or MEMS resonator,

-a printed circuit board (6) for carrying the resonator housing (5), which printed circuit board (6) comprises electrical connection terminals (18) for connection to the electrical contact pads (15) of the resonator housing,

characterized in that the resonator case (5) is fixedly held in a case structure (6, 9, 10) of the electronic module (1) and sandwiched between two damping elements (7, 8) for damping mechanical shocks, which hold the resonator case (5) and are pressed between two inner walls of the case structure of the electronic module (1),

the electrical contact pads (15) of the resonator housing being fixed directly on the electrical connection terminals (18) of the printed circuit board (6), the printed circuit board (6) being flexible, the resonator housing (5) fixed on the flexible printed circuit board (6) being fixedly held in the housing structure of the electronic module (1) and being sandwiched between the two damping elements (7, 8), a first damping element (7) of the two damping elements being in contact with the inner surface of a base (10) of the housing structure, a second damping element (8) of the two damping elements being in contact with the inner surface of a cover (9) of the housing structure, the cover (9) being fixed on the base (10),

the flexible printed circuit board (6) is connected to another rigid printed circuit board (16) carrying other electronic components (14).

2. Electronic module (1) according to claim 1, characterized in that the damping element is formed by one or more elastomeric elements.

3. Electronic module (1) according to claim 2, characterized in that a first damping element (7) is in contact with the entire lower surface of the resonator housing (5) and a second damping element (8) is in contact with the entire upper surface of the resonator housing (5).

4. Electronic module (1) according to claim 1, characterized in that the housing structure of the electronic module (1) comprises a base formed by the printed circuit board (6) and a cover (9) fixed on the printed circuit board (6), wherein a first damping element (7) is in contact with the lower surface of the printed circuit board (6).

5. Electronic module (1) according to claim 1, characterized in that said two damping elements are elastomeric elements pressed between the inner surface of said base (10) and the inner surface of said cover (9).

6. Electronic module (1) according to claim 1, characterized in that the flexible printed circuit board (6) and the rigid printed circuit board (16) form a single component.

7. An electronic module (1) according to claim 1, characterized in that the resonator housing (5) and the damping element are arranged in a first cavity of the housing structure (6, 9, 10) of the electronic module (1), and one or more electronic components (14) connected to the printed circuit board (6, 16) are arranged in a second cavity of the housing structure of the electronic module.

8. Electronic module (1) according to claim 1, characterized in that said resonator case (5) comprises a timepiece integrated circuit (4) and said quartz or MEMS resonator (3).