ELECTRONIC DEVICE AND TIMEPIECE

An electronic device including a first contact member, a second contact member which is arranged opposing the first contact member, a resilient conductive member which electrically connects the first contact member with the second contact member, and a resilient guide holding member having a guide portion which guides the resilient conductive member in opposing directions of the first contact member and the second contact member, and a resilient holding portion which holds the guide portion such that the guide portion is resiliently movable in the opposing directions of the first contact member and the second contact member.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2022-088952, filed May 31, 2022, the entire contents of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electronic device and a timepiece such as a wristwatch.

2. Description of the Related Art

For example, Japanese Patent Application Laid-Open (Kokai) Publication No. 2018-197759 discloses an electronic device such as a wristwatch which has a structure where a cylindrical member has been arranged between a circuit board and a solar panel, a coil spring has been inserted into and arranged in the cylindrical member so as to electrically connect the circuit board and the solar panel.

SUMMARY OF THE INVENTION

In order to solve the above-described problem, in accordance with one aspect of the invention, there is provided an electronic device comprising: a first contact member; a second contact member which is arranged opposing the first contact member; a resilient conductive member which electrically connects the first contact member with the second contact member; and a resilient guide holding member having a guide portion which guides the resilient conductive member in opposing directions of the first contact member and the second contact member, and a resilient holding portion which holds the guide portion such that the guide portion is resiliently movable in the opposing directions of the first contact member and the second contact member.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment in which the present invention has been applied in a wristwatch will hereinafter be described with reference toFIG.1toFIG.12B.

This wristwatch includes a wristwatch case1, as shown inFIG.1andFIG.2. On the six o'clock side and twelve o'clock side of the wristwatch case1, band attachment sections2are provided to which watch bands (not shown) are attached. In addition, on the two o'clock side, four o'clock side, eight o'clock side, and ten o'clock side of the wristwatch case1, switch sections3are provided.

In the structure of the above-described conventional technique, an end portion of the coil spring protrudes from an end of the cylindrical member and resiliently comes in contact with the circuit board or the solar panel. Accordingly, when the circuit board or the solar panel is rotated, deformation such as the buckling of the end portion of the coil spring protruding from the end of the cylindrical member may occur. That is, a stable and reliable connection between the circuit board and the solar panel cannot be achieved.

Therefore, a space is formed between the circuit board or the solar panel and an end of the cylindrical member corresponding thereto, and a buckling prevention section is formed on an end portion of the coil spring located in this space so as to prevent deformation such as the buckling of the end portion of the coil spring by this buckling prevention section and achieve a stable connection between the circuit board and the solar panel.

In this conventional structure, deformation such as the buckling of the coil spring can be suppressed by the buckling prevention section. However, there is a problem in that stress in the coil spring is increased by the presence of the buckling prevention section, and repulsive force against the circuit board and the solar panel is increased, whereby loads on the solar panel are increased.

The present embodiment is to improve this situation, and has a structure capable of preventing deformation such as buckling, lightening stress, and suppressing loads.

The wristwatch case1of the present embodiment includes a main body case4and an exterior case5, as shown inFIG.2toFIG.5. The main body case4is made of a metal such as stainless steel or a highly rigid synthetic resin, and has a substantially cylindrical shape. On the twelve o'clock side and six o'clock side of the main body case4, main body sections2aof the band attachment sections2are formed. In addition, on an inner circumferential portion of the main body case4, a flange section4ais formed projecting in a ring shape, as shown inFIG.4andFIG.5.

The exterior case5includes a first exterior member5awhich is arranged on an outer circumferential portion of the main body case4, and a second exterior member5bwhich is arranged on and covers the upper parts of the first exterior member5aand the main body case4, as shown inFIG.4andFIG.5. The first exterior member5aand the second exterior member are made of a metal such as stainless steel or a highly rigid synthetic resin, as with the main body case4.

On the twelve o'clock side and six o'clock side of the first exterior member5a,first cover sections2bof the band attachment sections2are provided which are arranged on the main body sections2aof the band attachment sections2, as shown inFIG.4andFIG.5(Note that, inFIG.4andFIG.5, only the first cover section2bon the twelve o'clock side is shown). Also, on the twelve o'clock side and six o'clock side of the second exterior member5b,second cover sections2cof the band attachment sections2are provided which are arranged on and cover the first cover sections2bof the band attachment sections2formed on the first exterior member5aand the main body sections2aof the band attachment sections2formed on the main body case4(Note that, inFIG.4andFIG.5, only the second cover section2con the twelve o'clock side is shown).

To the upper opening of the main body case4, a watch glass6is attached via a packing6a,as shown inFIG.4andFIG.5. In an area under this watch glass6, a ring-shaped parting member7having hour markers7a(refer toFIG.1) is arranged on the flange section4aof the main body case4. Also, to the lower part of the main body case4, a back cover8is attached via a waterproof ring8a.This back cover8is made of a conductive metal such as stainless steel.

On the outer circumferential side of the upper surface of the back cover8, or in other words, on the outer circumferential side of the inner surface of the back cover8, a circular frame section8bis formed, as shown inFIG.5. On the outer circumferential surface of this frame section8b,a male thread section8cis formed. As a result, the back cover8is structured to be attached to the lower part of the main body case4via the waterproof ring8aby the male thread section8cbeing screwed into and tighten in a female thread section4bformed in the inner circumferential surface of the lower opening of the main body case4.

More specifically, the back cover8is structured such that, when being screwed into the female thread section4bof the main body case4so as to be tighten, the male thread section8cis moved in the back-to-front direction of the wristwatch case1, that is, a vertical direction of the wristwatch case1while being laterally rotated with the back cover8, as shown inFIG.5. Also, in the main body case4, a timepiece module10is provided via a middle frame9(refer toFIG.10).

The timepiece module10has a housing11which is arranged in the middle frame9, as shown inFIG.4toFIG.9. This housing11is provided with a time indication display section12which displays and indicates the time by driving pointers12asuch as an hour pointer and a minute pointer, a display panel13which electrooptically displays information such as a time of day, a date, and a day of the week, an auxiliary information display section14which displays and indicates sub-functional information such as the remaining battery level of a battery15by driving a sub-pointer14a,and a battery15(refer toFIG.9).

On the lower part of this housing11, a circuit board16which is a first contact member is provided, as shown inFIG.4,FIG.5,FIG.7, andFIG.9. To this circuit board16, later-described electronic components such as a solar panel22and a piezoelectric element25are electrically connected in addition to the time indication display section12, the display panel13, the auxiliary information display section14, and the battery15. Also, under this circuit board16, a base plate17is provided. This base plate17is formed of a thin plate made of a metal such as stainless steel, and attaches the circuit board16to the undersurface of the housing11.

More specifically, this base plate17is structured such that a plurality of hook sections17aare provided upright on outer circumferential portions of this base plate17along the outer circumferential surface of the housing11(refer to FIG.9), and disengageably engage with a plurality of projection sections11bformed on the outer circumferential surface of the housing11, whereby the circuit board16is pressed against and attached to the undersurface of the housing11, as shown inFIG.4andFIG.5.

On the plurality of hook sections17aof the base plate17, contact springs17bare provided, as shown inFIG.8andFIG.9. These plural contact springs17bare plate springs extending along the outer circumference of the housing11, and provided corresponding to a plurality of push button switches3. More specifically, these contact springs17b,which force the push button switches3in directions in which the push button switches3are pressed toward the outside of the wristwatch case1, are structured to detachably come in contact with contact points (not shown) of the circuit board16when the push button switches3are pressed against the spring force, and thereby turn on the push button switches3.

On the other hand, on the upper surface of the housing11, a first dial plate20is arranged via a hold-down plate18having a ring shape, as shown inFIG.4andFIG.5. This first dial plate20is formed such that its outer circumference is substantially equal to those of the housing11and the hold-down plate18. As a result, the first dial plate20is structured such that its outer circumferential portion is arranged corresponding to the undersurface of the flange section4aof the main body case4while being arranged on the hold-down plate18.

In an area inside the hold-down plate18having the ring shape, a second dial plate21and the solar panel22are arranged overlapping with each other, as shown inFIG.4. The solar panel22is arranged on the upper surface of the housing11and its outer circumferential portion is arranged on a stepped section18aformed on the undersurface of the inner circumferential side of the hold-down plate18. Also, the second dial plate21, of which the outer circumference is formed to be substantially equal to the inner circumference of the hold-down plate18, is arranged on the solar panel22while being arranged within the inner circumference of the hold-down plate18.

The first dial plate20, above which the pointers12aof the time indication display section12are moved, is made of alight transmissive synthetic resin such as polycarbonate (PC), as shown inFIG.1, andFIG.4toFIG.6. Also, the second dial plate21, above which the sub-pointer14aof the auxiliary information display section14is rotated, is made of a light transmissive synthetic resin such as polycarbonate (PC), as in the case of the first dial plate20.

As a result, the solar panel22is structured such that external light that has entered into the wristwatch case1from the outside of the wristwatch case1through the watch glass6is applied to the solar panel22through the first dial plate20and the second dial plate21and generates electromotive force, as shown inFIG.4andFIG.5.

On the five o'clock side of the first dial plate20, the five o'clock side of the second dial plate21, the five o'clock side of the solar panel22, and the five o'clock side of the housing11, display window sections20bhaving substantially rhombus shapes are formed corresponding to the display area of the display panel13, as shown inFIG.1,FIG.6, andFIG.8. Also, in the center of the first dial plate20, the center of the second dial plate21, the center of the solar panel22, and the center of the housing11, through holes (not shown) are formed penetrating vertically, into which a pointer shaft (not shown) where the pointers12aof the time indication display section12are attached is inserted.

Moreover, on the nine o'clock side of the first dial plate20, a sub-display opening section20ahaving a circular shape is formed corresponding to a sub-display area where the sub-pointer14aof the auxiliary information display section14is rotated, as shown inFIG.1,FIG.4,FIG.5, andFIG.8. In a portion of the second dial plate21on the nine o'clock side, a portion of the solar panel22on the nine o'clock side, and a portion of the housing11on the nine o'clock side, insertion holes23corresponding to the center of the sub-display opening section20aof the first dial plate20are formed penetrating vertically, into which a sub-pointer shaft14bwhere the sub-pointer14aof the auxiliary information display section14is attached is inserted.

Furthermore, on an outer circumferential portion of the sub-display opening section20aof the first dial plate20, a decoration section24having a substantially semi-circular shape is formed, as shown inFIG.1,FIG.4toFIG.6, andFIG.8. This decoration section24, which is a decorative reinforcement member, has scale marks (not shown) that indicate sub-functional information such as the remaining battery level of the battery15by indication by the sub-pointer14a,and is made of a highly rigid synthetic resin. As a result, the timepiece module10is structured such that the flexural deformation of its portion corresponding to the decoration section24is suppressed.

To the upper surface of the back cover8, that is, the inner surface of the back cover8attached to the lower part of the wristwatch case1, a piezoelectric element25which is a second contact member is adhered by an adhesion layer26, as shown inFIG.5,FIG.11A, andFIG.11B. This piezoelectric element25, which vibrates and emits sounds when voltages are applied thereto, has a conductive section27provided on the center of its undersurface and is structured to be electrically connected to the back cover8by the conductive section27, as shown inFIG.11B.

The back cover8is structured such that a plate spring section17cprovided on the four o'clock side of the base plate17comes in contact with an upper surface (inner surface) portion of the back cover8located around the outer circumference of the piezoelectric element25, as shown inFIG.3,FIG.7, andFIG.9. As a result, the plate spring section17cis structured to electrically connect the circuit board16with the undersurface of the piezoelectric element25via the back cover8.

On the upper surface of the piezoelectric element25, an electric conduction guard plate28is provided, as shown inFIG.11B. This electric conduction guard plate28, which protects the upper surface of the piezoelectric element25, is made of a conductive metal such as stainless steel. As a result, the upper surface of the piezoelectric element25is electrically connected to the circuit board16by a coil spring30which is a resilient conductive member via the electric conduction guard plate28.

The coil spring30is made of a conductive metal such as stainless steel, as shown inFIG.12AandFIG.12B. This coil spring30has a large-diameter section30aand a small-diameter section30b.The large-diameter section30ais formed such that its outer diameter is greater than the inner diameter of a connection hole31formed penetrating vertically in the circuit board16, and the small-diameter section30bis formed such that its outer diameter is slightly shorter than the inner diameter of the connecting hole31of the circuit board16.

Also, this small-diameter section30bis formed such that its axial length, that is, its vertical length is greatly longer than the vertical length of the large-diameter section30aand slightly longer than the length from the circuit board16to the bottom of the middle frame9, as shown inFIG.12AandFIG.12B. As a result, the coil spring30is structured such that the small-diameter section30bis inserted from above into the connection hole31of the circuit board16and protrudes below the circuit board16, and this protruding lower end resiliently comes in contact with the upper surface of the piezoelectric element25of the back cover8via the electric conduction guard plate28, whereby the upper surface of the piezoelectric element25and the circuit board16are electrically connected to each other.

Also, the coil spring30is structured such that, by a hold-down member11cprovided in the housing11, the large-diameter section30ais resiliently pressed against the upper surface of the outer circumferential portion of the connection hole31in the circuit board16with the small-diameter section30bprotruding below the circuit board16, as shown inFIG.12AandFIG.12B.

Moreover, the coil spring30is structured such that, when pressed against the upper surface of the circuit board16, the large-diameter section30acomes in contact with an electrode (not shown) provided on the upper surface of the outer circumferential portion of the connection hole31in the circuit board16, whereby this coil spring30is electrically connected to the circuit board16. As a result, the coil spring30is structured to electrically connect the upper surface of the piezoelectric element25and the circuit board16via the electric conduction guard plate28.

Furthermore, the coil spring30is structured such that, by a resilient guide holding section32which is a resilient guide holding member, the small-diameter section30bis guided to be deformed in vertical directions that are opposing directions of the circuit board16and the piezoelectric element25, as shown inFIG.12AandFIG.12B. More specifically, the resilient guide holding section32is formed to be positioned in an opening section33provided in an area extending from the center of the bottom part of the middle frame9for housing and holding the housing11to the ten o'clock side thereof, as shown inFIG.3,FIG.7, andFIG.10.

The middle frame9is made of a synthetic resin such as polyacetal (POM). Similarly, the resilient guide holding section32is made of a synthetic resin such as polyacetal (POM), which is integrally formed in the bottom part of the middle frame9, as shown inFIG.3,FIG.7,FIG.10,FIG.12A, andFIG.12B. This resilient guide holding section32includes a guide section34which guides the small-diameter section30bof the coil spring30in the vertical directions and a spring section35which is a resilient holding portion that holds the guide section34such that it can be resiliently moved in the vertical directions.

The guide section34, which is a cylindrical section where the small-diameter section30bof the coiled spring30is inserted in a manner to be movable in axial directions which are vertical directions, is formed such that its length (height) is substantially equal to the thickness of the bottom part of the middle frame9, as shown inFIG.3,FIG.7,FIG.10,FIG.12A, andFIG.12B. The spring section35includes a plurality of plate springs and, in a planar view, has a substantially S shape as a whole. These plate springs constituting the spring section35are formed such that the thickness of each plate spring is substantially half the thickness of the bottom part of the middle frame9, the cylindrical guide section34is provided at the center of the substantially S shape in the planar view, and the ends of the substantially S shape are connected to edges of the opening section33of the middle frame9.

More specifically, the plurality of plate springs serving as the spring section35includes a plurality of first extending sections35aextending in mutually opposite directions from outer circumferential portions of the guide section34, a plurality of curved sections35bextending to be curved in directions different from the above-described mutually opposite directions from the plurality of first extending sections35a,and a plurality of second extending sections35cextending from the plurality of curved sections35bin directions different from the extending directions of the plurality of first extending sections35aso as to reach the edges of the opening section33of the middle frame9, as shown inFIG.3,FIG.7,FIG.10,FIG.12A, andFIG.12B.

For example, the plurality of first extending sections35aextends from the seven o'clock side and one o'clock side of the outer circumferential surface of the guide section34in directions opposite to the seven o'clock side and the one o'clock side, as shown inFIG.3. Of the plurality of curved sections35b,the curved section35bon the seven o'clock side is curved at an end of the first extending section35aon the seven o'clock side toward the four o'clock side, and the curved section35bon the one o'clock side is curved at an end of the first extending section35aon the one o'clock side toward the ten o'clock side.

Also, of the plurality of second extending sections35c, the second extending section35con the four o'clock side linearly extends toward the one o'clock side from the four o'clock side end of the curved section35bon the seven o'clock side, and reaches an inner peripheral edge portion of the opening section33of the middle frame9on the one o'clock side, as shown inFIG.3. The second extending section35con the ten o'clock side linearly extends toward the seven o'clock side from the ten o'clock side end of the curved section35bon the one o'clock side, and reaches an inner peripheral edge portion of the opening section33of the middle frame9on the seven o'clock side.

As a result, by the plurality of plate springs, the spring section35is formed in a substantially S shape as a whole in a planar view, and thereby structured such that the guide section34can be linearly, that is, vertically moved in the vertical directions of the timepiece module10without being laterally oscillated, as shown inFIG.12AandFIG.12B.

As a result of this structure, the coil spring30is structured such that, when the back cover8is being attached to the lower part of the wristwatch case1with the small-diameter section30bbeing positioned in the connection hole31of the circuit board16and the large-diameter section30abeing pressed against the electrode (not shown) on the upper surface of the circuit board16, deformation such as the buckling of the small-diameter section30bdoes not occur by the presence of the resilient guide holding section32in spite of the piezoelectric element25being rotated to be gradually moved upward together with the back cover8and pressed against the lower end of the small-diameter section30bvia the electric conduction guard plate28, as shown inFIG.12AandFIG.12B.

That is, the coil spring30is structured such that, when the piezoelectric element25is being rotated to be gradually moved upward together with the back cover8that is attached to the lower part of the wristwatch case1with the lower end of the small-diameter section30bbeing pressed against the piezoelectric element25via the electric conduction guard plate28, the small-diameter section30bis not deformed to be buckled but deformed to be compressed by being guided in a vertical direction by the guide section34of the resilient guide holding section32in spite of the lower end of the small-diameter section30bbeing relatively moved on the electric conduction guard plate28of the piezoelectric element25along with the rotation and movement of the piezoelectric element25, as shown inFIG.12AandFIG.12B.

Also, the coil spring30is structured such that, when the piezoelectric element25is rotated to be gradually moved upward together with the back cover8that is attached to the lower part of the wristwatch case1, the upper surface of the electric conduction guard plate28of the piezoelectric element25approaches and comes in contact with the lower end surface of the guide section34of the resilient guide holding section32, whereby stress in the coil spring30is lightened as compared to the above-described conventional technology having the buckling prevention section, the repulsion force of the coil spring30with respect to the piezoelectric element25is reduced to a low level, and loads on the piezoelectric element are suppressed, as shown inFIG.12AandFIG.12B.

As such, the piezoelectric element25is structured such that the repulsion force of the coil spring30with respect to the piezoelectric element25when the lower end of the small-diameter section30bof the coil spring30is pressed against the piezoelectric element25via the electric conduction guard plate28is reduced to a low level as compared to the above-described conventional technology, and therefore loads on the piezoelectric element25due to the repulsion force of the coil spring30are suppressed, whereby the volume of a sound by vibration generated by a voltage being applied satisfies a specified value, as shown inFIG.12AandFIG.12B.

Also, the coil spring30is structured such that, when the back cover8is rotated to be loosened and the piezoelectric element25and the back cover8are moved downward in a direction away from the circuit board16, the small-diameter section30bgradually expands and protrudes from and below the guide section34of the resilient guide holding section32, as shown inFIG.12AandFIG.12B.

That is, the coil spring30and the resilient guide holding section32are structured such that, when the back cover8is detached from the main body case4, the small-diameter section of the coil spring30returns to its initial state, and the guide section34of the resilient guide holding section32and the spring section35thereof also return to their initial states, as shown inFIG.12AandFIG.12B. As a result, the spring section35is structured not to be plastically deformed when the back cover8is screwed onto the main body case4and tightened.

Next, a procedure for assembling this wristwatch is described.

First, the timepiece module10is assembled. In this assembly, first, the time indication display section12, the display panel13, and the secondary information display section14are arranged in the housing11. More specifically, the time indication display section12is arranged corresponding to a substantially central portion of the housing11, the display panel13is arranged corresponding to the five o'clock side of the housing11, and the secondary information display section14is arranged corresponding to a substantially nine o'clock side of the housing11.

In this state, the circuit board16is arranged on the undersurface of the housing11. Here, the time instruction display section12, the display panel13, and the auxiliary information display14are electrically connected to the circuit board16. In addition, the coil spring30is attached to the circuit board16. More specifically, the small-diameter section30bof the coil spring30is inserted from above into the connection hole31of the circuit board16in a manner to protrude below the circuit board16and, in this state, the large-diameter section30ais arranged on the upper surface of the outer circumferential portion of the connection hole31.

Then, the base plate17is arranged under the circuit board16, and the plurality of hook sections17aformed upright on the outer circumferential portions of the base plate17is locked to the plurality of projection sections11bformed on outer circumferential portions of the housing11. As a result, the circuit board16is attached to the undersurface of the housing11by the base plate17, and the contact springs17bformed on the plurality of hook sections17aare arranged on the two o'clock side, four o'clock side, eight o'clock side, and ten o'clock side of the housing11.

Here, the large-diameter section30aof the coil spring30is pressed against the upper surface of the circuit board16by the hold-down member11cprovided in the housing11. As a result, the large-diameter section30ais resiliently connected to the electrode (not shown) provided on the upper surface of the outer circumferential portion of the connection hole31in the circuit board16, and thereby electrically connected to the circuit board16. In the housing11, the time indication display section12, the display panel13, and the secondary information display section14have been mounted with them being electrically connected to the circuit board16.

Then, the solar panel22is arranged on the upper surface of the housing11, and the second dial plate21is arranged on the solar panel22. In this state, the hold-down plate18having a ring shape is arranged on an upper surface portion of the housing11located around the outer circumferences of the solar panel22and the second dial plate21, and the first dial plate20is arranged on the hold-down plate18. In addition, the pointer shaft (not shown) of the time indication display section12is inserted into through holes (not shown) coaxially formed in the center of the solar panel22, the center of the second dial plate21, and the center of the first dial plate20.

Here, the display area of the display panel13is positioned corresponding to the display window sections20bformed on a substantially five o'clock side of the solar panel22, a substantially five o'clock side of the second dial plate21, a substantially five o'clock side of the first dial plate20. In addition, the sub-pointer shaft14bof the secondary information display section14is inserted into the insertion holes23coaxially formed on a substantially nine o'clock side of the solar panel22and a substantially nine o'clock side of the second dial plate21, and thereby arranged in the circular sub-display opening section20aformed on a substantially nine o'clock side of the first dial plate20.

In this state, when attached to the pointer shaft (not shown) of the time indication display section12, the pointers12aare set in a state where they can be driven above the first dial plate20. In addition, when attached to the sub-pointer shaft14bof the secondary information display section14, the sub-pointer14ais positioned in the circular sub-display opening section20aof the first dial plate20, and set in a state where it can be rotated above the second dial plate21. As a result of this procedure, the assembly of the timepiece module10is completed.

Next, a procedure for mounting the timepiece module10assembled as described above in the wristwatch case1is described.

In this procedure, first, the ring-shaped parting member7is inserted from above into the upper part of the main body case4of the wristwatch case1, and arranged on the ring-shaped flange section4aprovided in the main body case4. In this state, the watch glass6is fitted from above into the upper opening of the main body case4together with the packing6a,and the parting member7is pressed against and fixed on the flange section4aof the main body case4by this watch glass6.

Subsequently, a first buffering member36is arranged on the undersurface of the timepiece module10, and the timepiece module10is arranged in the middle frame9. Here, the small-diameter section30bof the coil spring30protruding below the circuit board16is inserted into the guide section34of the resilient guide holding section32in the bottom part of the middle frame9such that a lower end portion of the small-diameter section30bprotrudes below the guide section34. In this state, the timepiece module10is inserted from below into the main body case4together with the middle frame9, and the outer circumferential portion of the first dial plate20of the timepiece module10is brought into contact with the undersurface of the flange section4aof the main body case4.

Then, the push button switches3are attached to the two o'clock side, four o'clock side, eight o'clock side, and ten o'clock side of the main body case4. Here, these plural push button switches3are positioned corresponding to the plurality of contact springs17bprovided on the base plate17of the timepiece module10. In this state, the exterior case5is attached to the outer circumferential portion of the main body case4. Here, the first exterior member5aof the exterior case5is attached to the outer circumferential portion of the main body case4, and the second exterior member5bof the exterior case5is attached to the outer circumferential portion of this first exterior member5aand the upper part of the main body case4. As a result, the assembly of the wristwatch case1is completed.

In this state, the back cover8is attached to the lower part of the wristwatch case1, or more specifically, the lower part of the main body case4. Before this attachment, a second buffering member37is arranged on the undersurface of the bottom part of the middle frame9. In addition, the piezoelectric element25is attached to the inner surface (upper surface) of the back cover8by the adhesion layer26. Here, the undersurface of the piezoelectric element25and the back cover8are electrically connected to each other by the conductive section27provided on the center of the undersurface of the piezoelectric element25. Then, the electric conduction guard plate28is arranged on the upper surface of the piezoelectric element25, and the back cover8is attached to the lower part of the main body case4.

In this attachment, the male screw section8cformed on the outer circumferential surface of the frame section8bof the back cover8is screwed into the female screw section4bin the inner circumferential surface of the lower opening of the main body case4and tightened. As a result, the back cover8is attached to the lower part of the main body case4. Here, since the back cover8is gradually moved toward the upper side of the main body case4while being laterally rotated, the small-diameter section30bof the coil spring30is guided by the guide section34of the resilient guide holding section32and the lower part of the small-diameter section30bis pressed into the guide section34.

Here, since the guide section34has been held in a manner to be resiliently movable in the vertical directions of the timepiece module10by the spring section35, or in other words, since the spring section35has a substantially S shape as a whole in a planar view by including the plurality of plate springs, the guide section34is linearly, that is, vertically moved in the vertical directions of the timepiece module10without being laterally oscillated.

Therefore, when the back cover8is being attached to the lower part of the wristwatch case1with the small-diameter section30bof the coil spring30being positioned in the connection hole31of the circuit board16and the large-diameter section30athereof being pressed against the electrode (not shown) on the upper surface of the circuit board16, the small-diameter section30bis not deformed to be buckled but deformed to be compressed by the presence of the resilient guide holding section32in spite of the piezoelectric element25being rotated to be gradually moved upward together with the back cover8and pressed against the lower end of the small-diameter section30bvia the electric conduction guard plate28.

That is, when the piezoelectric element25is being rotated to be gradually moved upward together with the back cover8that is attached to the lower part of the wristwatch case1with the lower end of the small-diameter section30bof the coil spring30being pressed against the piezoelectric element25via the electric conduction guard plate28, the small-diameter section30bis not deformed to be buckled by being guided in a vertical direction by the guide section34of the resilient guide holding section32in spite of the lower end of the small-diameter section30bbeing relatively moved on the electric conduction guard plate28of the piezoelectric element25along with the rotation and movement of the piezoelectric element25.

Also, when the piezoelectric element25is rotated to be gradually moved upward together with the back cover8that is attached to the lower part of the wristwatch case1, the upper surface of the electric conduction guard plate28of the piezoelectric element25approaches and comes in contact with the lower end surface of the guide section34of the resilient guide holding section32, whereby the repulsion force of the middle frame9(the guide section34) with respect to the piezoelectric element25is reduced to a low level as compared to the above-described conventional technology having the buckling prevention section. Accordingly, the circuit board16and the upper surface of the piezoelectric element25are connected with loads on the piezoelectric element25being suppressed.

As such, the repulsion force of the middle frame9(the guide section34) with respect to the piezoelectric element25when the lower end of the small-diameter section30bof the coil spring30is pressed against the piezoelectric element25via the electric conduction guard plate28is reduced to a low level, and therefore loads on the piezoelectric element25are suppressed as compared to the above-described conventional technology having the buckling prevention section, whereby the volume of a sound by the vibration of the piezoelectric element25generated by a voltage being applied to the piezoelectric element25satisfies a specified value.

Here, the plate spring section17cprovided on the four o'clock side of the base plate17comes in contact with an inner surface portion of the back cover8located around the outer circumference of the piezoelectric element25. As a result, the back cover8to which the undersurface of the piezoelectric element25has been connected is electrically connected to the circuit board16. Accordingly, the piezoelectric element25is electrically connected to the circuit board16by an electrode on its upper surface side being connected to the circuit board16by the coil spring30and an electrode on its lower surface side being connected to the circuit board16by the plate spring section17cof the base plate17.

In a case where the back cover8is detached from the lower part of the main body case4, the back cover8is rotated and loosened. Here, the piezoelectric element25is moved downward in a direction away from the circuit board16together with the back cover8, whereby the small-diameter section30bof the coil spring30gradually expands and protrudes below the guide section34. Then, when the back cover8is detached from the main body case4, the small-diameter section30bof the coil spring30and the resilient guide holding section32return to their initial states.

Next, the usage of the wristwatch worn on an arm is described.

In the case of this wristwatch, normally, information such as a time of day, a date, and a day of the week, and sub-functional information such as the remaining battery level of the battery15can be checked by the timepiece module10. That is, the pointers12aof the time indication display section12of the timepiece module10are driven above the first dial plate20so as to indicate the time, whereby the time can be checked.

In addition, the display panel13of the timepiece module10electro-optically displays information such as a time of day, a date, and a day of the week, whereby the information such as a time of day, a date, and a day of the week can be checked through the display window sections20b.Moreover, the sub-pointer14aof the secondary information display section14of the timepiece module10is rotated above the second dial plate21in the sub-display opening section20aof the first dial plate20so as to indicate sub-functional information such as the remaining battery level of the battery15, whereby the sub-functional information such as the remaining battery level of the battery15can be checked.

When a preset time is reached, an alarm sound is emitted. More specifically, when a preset time is reached, a voltage is applied to the piezoelectric element25from the circuit board16. As a result, the piezoelectric element25is vibrated and resonates the back cover8, whereby an alarm sound is emitted to inform that the set time has been reached.

In the present embodiment, stress in the coil spring30is lightened as compared to the above-described conventional technology having the buckling prevention section, and the repulsion force of the coil spring30with respect to the piezoelectric element25and the repulsion force of the middle frame9(the guide section34) with respect to the piezoelectric element25are reduced to low levels, whereby loads on the piezoelectric element25are suppressed and the volume of a sound by the vibration of the piezoelectric element25generated by a voltage being applied to the piezoelectric element25satisfies a specified value. As a result of this structure, alarm sounds can be favorably emitted.

As described above, this wristwatch includes the circuit board16which is a first contact member, the piezoelectric element25which is a second contact member arranged opposing the circuit board16, the coil spring30which is a resilient conductive member for electrically connecting the circuit board16with the piezoelectric element25, and the resilient guide holding section32having the guide section34which guides the coil spring30in the vertical directions that are the opposing directions of the circuit board16and the piezoelectric element25, and the spring section35which is a resilient holding portion that holds the guide section34such that the guide section34can be resiliently moved in the vertical directions, whereby deformation such as buckling can be prevented and the stress can be lightened.

That is, in the case of this wristwatch where the guide section34of the resilient guide holding section32is held by the spring section35in a manner to be resiliently movable in the vertical directions and the coil spring30is guided in the vertical directions by the guide section34, deformation such as the buckling of the coil spring30can be reliably and favorably prevented even when the piezoelectric element25approaches the circuit board16while being laterally rotated. In addition, the repulsion force of the middle frame9(the guide section34) with respect to the piezoelectric element25can be reduced to a low level, whereby loads on the piezoelectric element25can be suppressed as compared to the above-described conventional technology having the buckling prevention section.

Also, in the case of this wristwatch, the spring section35has a plurality of plate springs including the plurality of first extending sections35aextending in mutually opposite directions from the guide section34, the plurality of curved sections35bextending to be curved in directions different from the above-described mutually opposite directions from the plurality of first extending sections35a,and the plurality of second extending sections35cextending from the plurality of curved sections35bin directions different from the extending directions of the plurality of first extending sections35a,whereby the guide section34can be linearly moved in up-and-down directions or, in other words, resiliently moved in vertical directions without being laterally oscillated. Accordingly, deformation such as the buckling of the coil spring30can be prevented and the stress of the guide section34formed on the bottom of the middle frame9can be lightened, whereby loads on the opposing member can be reduced.

As such, in the case of this wristwatch, the guide section34can be linearly moved in the up-and-down directions or, in other words, resiliently moved in the vertical directions by the spring section35without being laterally oscillated, whereby the stress of the middle frame9(the guide section34) can be lightened and the repulsion force of the middle frame9(the guide section34) with respect to the piezoelectric element25can be reduced to a low level. As a result, loads on the piezoelectric element25can be suppressed as compared to the above-described conventional technology having the buckling prevention section, whereby the circuit board16and the piezoelectric element25can be reliably and favorably connected to each other, and the piezoelectric element25can be favorably vibrated so as to favorably emit sounds.

Also, in the case of this wristwatch, even when the piezoelectric element25serving as a second contact member is laterally rotated so as to be moved in a vertical direction that is an opposing direction of the circuit board16and the piezoelectric element25, deformation such as the buckling of the coil spring30can be reliably and favorably prevented by the resilient guide holding section32. As a result of this structure, the circuit board16and the piezoelectric element25can be reliably and favorably connected to each other by the piezoelectric element25approaching the circuit board16.

Moreover, in this wristwatch, the circuit board16serving as a first contact member is mounted in the housing11that is arranged in the wristwatch case1, and the resilient guide holding section32is provided in the middle frame9that holds the housing11so that the housing11is arranged in the wristwatch case1. As a result of this structure, the resilient guide holding section32is not required to be manufactured as a separate part, whereby the number of parts of the wristwatch can be reduced and the assembly thereof can be simplified.

Furthermore, in this wristwatch, the piezoelectric element25serving as a second contact member is attached to the inner surface of the back cover8that is screwed onto the lower part of the wristwatch case1. As a result of this structure, the piezoelectric element25can be arranged on the lower side of the wristwatch case1together with the back cover8, and the back cover8can be used as a diaphragm, whereby sounds such as alarm sounds can be favorably emitted by the vibration of the piezoelectric element25being resonated on the back cover8.

In the above-described embodiment, the spring section35of the resilient guide holding section32includes a plurality of plate springs which has a substantially S shape in a planar view. However, the spring section35of the present invention is not necessarily required to be constituted by a plurality of plate springs. This spring section35may be constituted by only one plate spring, or may be constituted by three or more plate springs.

Also, the present invention is not limited to the above-described structure and may have a structure where the spring section35of the resilient guide holding section32has a spiral shape, a helix shape, or a bellows shape. In addition, the spring section35of the resilient guide holding section32is not necessarily required to be formed using plate springs, and may be formed using elastic members such as rubber and elastomer. That is, in the present invention, any material can be used to form the resilient guide holding section32as long as it can hold the guide section34such that the guide section34is resiliently or elastically movable in the attachment and detachment directions of the circuit board16and the piezoelectric element25.

Moreover, as a resilient conductive member, the coil spring30is used in the above-described embodiment. However, the present invention is not limited thereto. For example, a stick-shaped or pillar-shaped conductive rubber may be used.

Furthermore, in the above-described embodiment, the resilient guide holding section32is provided in the middle frame9. However, the present invention is not limited thereto, and the resilient guide holding section32may be provided in the housing11or the base plate17which is insulative. That is, the resilient guide holding section32may be provided in any insulating member of the timepiece module10as long as it is a member to be arranged close to the piezoelectric element25of the back cover8. In addition, the resilient guide holding section32may be separately manufactured and mounted in the housing11.

Still further, in the above-described embodiment, the circuit board16is a first contact member and the piezoelectric element25is a second contact member. However, the present invention is not limited thereto, and the second contact member may be another connecting member such as the solar panel22. In addition, the first contact member is not necessarily required to be the circuit board16, and may be another connecting member.

Yet still further, in the above-described embodiment, the present invention has been applied in a wristwatch. However, the present invention is not necessarily required to be applied in a wristwatch. For example, the present invention is applicable to various types of timepieces such as a travel watch, an alarm clock, a table clock, and a wall clock. In addition, the present invention is not necessarily required to be applied in timepieces, and can be applied in electronic devices such as cell-phones and portable information terminals.