Electronic timepiece

An embodiment of an electronic timepiece includes a cylindrical exterior case, a bezel and a windshield member. In the exterior case, a circuit board is housed. The bezel is formed of a metal material to be ring-shaped, includes an inward flange part that projects from an inner side surface toward a center of the ring-shaped bezel, is arranged on an outer upper side of the exterior case and is electrically connected with the circuit board. The windshield member is formed of a transparent dielectric substance, arranged in the bezel and supported by the inward flange part. The bezel is configured to resonate with a radio wave having a desired frequency by adjustment of at least one of (i) a relative permittivity of the dielectric substance and (ii) an area of an overlap region where the inward flange part and the windshield member overlap each other.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2017-215010, filed on Nov. 7, 2017, the entire contents of which are incorporated herein by reference.

BACKGROUND

1. Technical Field

The technical field relates to an electronic timepiece.

2. Description of the Related Art

There is known an electronic timepiece, such as a watch, which receives satellite radio waves to acquire accurate time information, position information and so forth. (Refer to, for example, JP 2009-168656 A.)

The electronic timepiece described in JP 2009-168656 A has a dial as ground and an antenna arranged at a concealing portion between the dial and a windshield member (cover glass).

The configuration described in JP 2009-168656 A makes the timepiece as a whole thick because the antenna is arranged on the dial.

In particular, if the antenna is large to receive radio waves having a desired frequency, a timepiece case also needs to be large, so that the electronic timepiece is large.

Further, because the dial is used as the ground, the dial needs to be formed of a metal material, for example. Hence, the range of choice about material and arrangement of the dial is limited, for example.

SUMMARY

An electronic timepiece is disclosed herein.

An electronic timepiece according to a preferred embodiment includes: a cylindrical exterior case in which a circuit board is housed; a bezel which is formed of a metal material to be ring-shaped, includes an inward flange part that projects from an inner side surface of the ring-shaped bezel toward a center of the ring-shaped bezel, is arranged on an outer upper side of the exterior case, and is electrically connected with the circuit board; and a windshield member which is formed of a transparent dielectric substance, arranged in the bezel, and supported by the inward flange part, wherein the bezel is configured to resonate with a radio wave having a desired frequency by adjustment of at least one of (i) a relative permittivity of the dielectric substance which forms the windshield member and (ii) an area of an overlap region where the inward flange part and the windshield member overlap each other.

DETAILED DESCRIPTION

Hereinafter, an embodiment(s) is described in detail with reference to the drawings. In the embodiment(s), a watch having a bezel as an exterior member having an antenna function is described as an electronic timepiece. However, the scope of the present invention is not limited to the embodiment(s) or illustrated examples.

FIG. 1is a front view of an electronic timepiece according to an embodiment(s).

As shown inFIG. 1, an electronic timepiece100includes a case (hereinafter referred to as “exterior case1”).

The exterior case1is formed of hard resin, such as an ABS resin.

The material for forming the exterior case1is not limited to resin. Usable examples thereof include: metal including stainless steel and titanium; ceramic; and other various materials.

As described below, in this embodiment, on the upper side of the exterior case1, a bezel2which functions as an antenna is mounted. Hence, if the exterior case1is formed of a conductive material, such as a metal material, it is preferable that an insulating low-loss resin or the like which has a certain level of relative permittivity and does not greatly change frequency characteristics of the bezel2as an antenna be interposed between the exterior case1and the bezel2in order to insulate the exterior case1and the bezel2from one another.

Even if the exterior case1is formed of a resin material, a reinforcing material may be mixed with the resin material so that the exterior case1can have strength. In this case, it is preferable that a nonconductive material, such as glass fiber, be used as the reinforcing material.

FIG. 2is a perspective view of the exterior case1.FIG. 3is a sectional side view of the electronic timepiece100of this embodiment.

As shown inFIG. 2, the exterior case1is approximately cylindrical. The upper side and the lower side of the exterior case1in its thickness direction (the up-down direction inFIG. 3) are opened such that the exterior case1is hollow. This hollow portion serves as storage space where various components are housed.

At both ends in the up-down direction inFIG. 1(at 12 o'clock and 6 o'clock in an analog timepiece) of the exterior case1, belt attachment parts11are formed. To the belt attachment parts11, a not-shown timepiece belt (s) can be attached.

Further, as described below, the bezel2and a buffer member4(4ato4c) are fixed to the exterior case1with screws or the like. At points on the exterior case1corresponding to screw insertion positions, holes13are formed. (Refer toFIG. 2andFIG. 3.)

On the outer circumferential surface of the exterior case1, operation buttons12(operation buttons12aand12b) to input various operation instructions, such as instructions for time adjustment, are arranged. At the positions on the exterior case1for the operation buttons12, through holes14through the exterior case1are formed.

FIG. 4andFIG. 5are partially exploded perspective views showing configuration of each operation button12.

As shown inFIG. 4, the electronic timepiece100of this embodiment has the operation buttons12awhich are push buttons arranged at positions for approximately 2 o'clock, 4 o'clock, 8 o'clock and 10 o'clock in an analog timepiece.

Each push operation button12aincludes a body121which is operated by a user with his/her finger, a buffer member122which serves as a cushion and absorbs impact or the like when the operation button12ais operated, and a button pipe123which holds the body121in a state in which the body121is housed in the button pipe123.

The tip of the button pipe123is inserted into the exterior case1from the through hole14, and when the body121of the operation button12ais operated, this operation is transmitted to timepiece modules or the like arranged in the exterior case1.

As shown inFIG. 5, the electronic timepiece100of this embodiment has the operation button12bwhich is a winding crown arranged at a position for approximately 3 o'clock in an analog timepiece.

The winding operation button12bincludes a body124, a spacer125and a buffer member126which serves as a cushion and absorbs impact when the operation button12bis operated.

The body124includes a shaft part124aone end of which is inserted into the exterior case1from the through hole14, and a head part124bwhich is arranged on the other end of the shaft part124aand operated by a user with his/her finger.

When the body124of the operation button12bis rotationally operated by a user, this operation is transmitted to the timepiece modules or the like arranged in the exterior case1.

As shown inFIG. 3, in the storage space of the exterior case1, various modules (timepiece modules) for the electronic timepiece100to function as a timepiece are housed. The various modules includes: a housing7in which a battery (cell)74and so forth are arranged; a circuit board (circuit board71) arranged on the upper surface of the housing7; a pressing plate73which suppresses ricketiness of components, such as the circuit board71; and a liquid crystal panel55as a display.

The housing7, the circuit board71and so forth are fixed with a screw (s)75so that their unsteadiness, dislocation and so forth in the exterior case1are prevented.

The liquid crystal panel55is placed on a panel placement part17formed in the exterior case1, and electrically connected with the circuit board71via a wiring member56constituted of a flexible wiring circuit board or the like.

The liquid crystal panel55displays various types of information, such as time, a date, a day of a week and position information. In this embodiment, the liquid crystal panel55is exposed to the visible side via a ring-shaped dial5, which is described below, to be visible through a windshield member3(cover glass, to be specific).

The display is not limited to the liquid crystal panel55. Examples usable as the display include various display units made of, for example, organic EL (ElectroLuminescence).

The circuit board71is a circuit to receive radio waves with an antenna, and provided with a functional component set72constituted of various circuits including an antenna circuit, electronic components, and so forth all of which are not shown.

FIG. 6is a perspective view of the exterior case1viewed from the back surface side (an invisible side or the lower side inFIG. 3), the exterior case1shown inFIG. 2being reversed.

As shown inFIG. 2andFIG. 6, at or near a position which is on the outer edge portion of the exterior case1and corresponds to the antenna circuit mounted on the circuit board71, a notched part150and circuit connection hole parts15are provided to insert a connecting member25which electrically connects the below-described bezel2with the circuit board71.

Although the position and shape of the notched part150, the number and arrangement of the circuit connection hole parts15to be provided, and so forth are not particularly limited, in this embodiment, the notched part150which is approximately arc-shaped along the shape of the outer edge of the exterior case1is formed at a position for 4 o'clock to 5 o'clock in an analog timepiece, and four circuit connection hole parts15are formed next to one another along a side of the notched part150close to the outer circumference of the exterior case1.

Further, at a position which is on the outer edge portion of the exterior case1and is different from the position of the notched part150and the circuit connection hole parts15, a notched part160and ground connection hole parts16are provided to insert a not-shown ground terminal which connects the bezel2to the ground.

Although the position and shape of the notched part160, the number and arrangement of the ground connection hole parts16to be provided, and so forth are not particularly limited, in this embodiment, the notched part160which is approximately arc-shaped along the shape of the outer edge of the exterior case1is formed at a position for 7 o'clock to 8 o'clock in an analog timepiece, and five ground connection hole parts16are formed next to one another along a side of the notched part160close to the outer circumference of the exterior case1.

As shown inFIG. 3, to the lower side (back surface) of the exterior case1(the lower side inFIG. 3or the invisible side), a back cover member8as a closing member which closes the opening in the back surface of the exterior case1is attached via a waterproof ring81. The back cover member8is formed of a metal material, such as stainless steel or titanium, for example.

The material for forming the back cover member8is not limited to those exemplified herein. Usable examples thereof include various resin materials including an ABS resin.

The back cover member8is fixed to the exterior case1with a screw82.

On the outer upper side of the exterior case1(the upper side inFIG. 3, the visible side or the front surface side), the bezel2is arranged.

In this embodiment, the bezel2is configured to resonate with radio waves having a desired frequency, and functions as an antenna.

It is preferable that the radio waves having a desired frequency receivable by the bezel2, which functions as an antenna, include radio waves transmitted from satellites.

For example, radio waves transmitted from GPS (Global Positioning System) satellites and radio waves transmitted from QZSS (Quasi-Zenith Satellite System), which are quasi-zenith satellites of Japan, have a frequency of 1575.42 MHz, and radio waves transmitted from GLONASS (GLObal NAvigation Satellite System) have a frequency band the center frequency of which is 1602.5625 MHz.

In this embodiment, the bezel2is made to function as an antenna which can receive radio waves having a desired frequency by appropriate setting of various conditions about the bezel2, the below-described windshield member3and so forth.

For example, if the bezel2is configured to resonate with radio waves having a frequency of 1575.42 MHz for GPS and so forth and/or radio waves having a frequency of 1602.5625 MHz for GLONASS, the bezel2can receive radio waves transmitted from GPS and/or GLONASS. Consequently, the electronic timepiece100can make use of time information and position information contained in these radio waves.

The radio waves having a desired frequency receivable by the bezel2, which functions as an antenna, are not limited to the radio waves transmitted from GPS satellites and so forth described above.

In this embodiment, the bezel2is formed of a metal material, such as SUS316 (stainless steel 316), to be ring-shaped, for example.

The material for forming the bezel2is not limited to SUS316.

However, in this embodiment, as described above, the bezel2is configured to function as an antenna which resonates with radio waves having a desired frequency. From this point, it is considered that if conductivity of the material forming the bezel2is low (resistivity thereof is high), sufficient antenna gain cannot be obtained.

To make the bezel2function as an antenna having excellent antenna gain, it is preferable to use, as the material for forming the bezel2, a metal material having a certain level of conductivity or higher (i.e. having a certain level of resistivity or lower) and a certain level of magnetic permeability or lower.

From this point, as the material for forming the bezel2of this embodiment, for example, the following metal materials can be used: the abovementioned SUS316 (resistivity (μΩ·cm) of 74); SUS304 (resistivity (μΩ·cm) of 72); silver (resistivity (μΩ·cm) of 1.62); copper (resistivity (μΩ·cm) of 1.72); titanium (Ti) (resistivity (μΩ·cm) of 55); Nichrome (alloy of Ni, Fe and Cr) (resistivity (μΩ·cm) of 109); and Ti64 (resistivity (μΩ·cm) of 166). The above metal materials have a magnetic permeability (relative magnetic permeability) of about 1.

The material for forming the bezel2should be appropriately selected in accordance with the frequency of radio waves desired to be received by the bezel2as an antenna and other various conditions, and hence is not limited to those exemplified herein.

FIG. 7is a perspective view showing the bezel2and components surrounding the bezel2.FIG. 8is an exploded perspective view showing the bezel2and components to be arranged in the bezel2.

As shown inFIG. 7andFIG. 8, the bezel2has an inward flange part21which projects from the inner side surface (inner circumferential surface) of the ring-shaped bezel2toward the center of the ring-shaped bezel2.

The inward flange part21of this embodiment includes: a first stage flange21a; and a second stage flange21bwhich is formed on a further lower side than the first stage flange21a(the lower side inFIG. 8) and projects further toward the center of the ring-shaped bezel2than the first stage flange21a.

On the upper surface (the surface on the upper side inFIG. 8) of the second stage flange21b, the outer edge of the dial5is placed.

The dial5of this embodiment includes an upper dial51and a lower dial52which are adhesively fixed to one another with an adhesive member53constituted of, for example, a double-sided tape not to be dislocated, thereby being integrated with one another.

The lower surface of the dial5(the back surface of the lower dial52) is adhesively fixed to the upper surface of the second stage flange21bwith an adhesive member54constituted of a double-sided tape or the like so that the dial5is not dislocated.

On the upper surface (the surface on the upper side inFIG. 8) of the first stage flange21a, the outer edge of the windshield member3is placed via a spacer32.

If a component under the windshield member3(the dial5, in this embodiment) is not sufficiently fixed, the component may contact or stick to the lower surface of the windshield member3. The spacer32is for preventing this situation from happening and catches the outer edge of the windshield member3.

It is preferable that the spacer32be subjected to glass printing or the like so as to be invisible from the outside.

The spacer32is formed of PET (PolyEthylene Terephthalate, i.e. a PET resin), for example. Although its forming method is not particularly limited, a method of cutting out a pattern from (i.e. punching out in) a PET sheet can be used, for example.

In addition to the forming method, the material for forming the spacer32is not particularly limited, either.

Usable examples as the spacer32include double-sided tapes having a certain level of hardness, components molded from an ABS resin, a polycarbonate (PC) resin and so forth, and components formed of various metal materials.

In the bezel2(the first stage flange21aof the bezel2, in this embodiment), a waterproof ring31is arranged. The windshield member3is press-fitted into the bezel2with the waterproof ring31in between, so that the windshield member3is fitted in and fixed to the ring-shaped bezel2, and is supported by the inward flange part21(the first stage flange21a, in this embodiment).

Configuration of the inward flange part21is not limited to that exemplified herein.

For example, the exterior case1may have a supporting part which supports the dial5, and the inward flange part21may be a flange part having only one stage (corresponding to the first stage flange21ain this embodiment) which supports the windshield member3.

The windshield member3is formed of a transparent material and is a cover glass which covers the visible side of the electronic timepiece100. The windshield member3is supported by the inward flange part21of the bezel2.

In this embodiment, the windshield member3is formed of a dielectric substance. Examples thereof include various types of glass including super white glass, and sapphire (transparent synthetic sapphire).

In this embodiment, the bezel2is made to function as an antenna. Hence, use of the dielectric substance as the material for forming the windshield member3, which is contiguous with the bezel2, can promise increase in antenna gain of the bezel2as an antenna.

In this embodiment, the bezel2is configured to resonate with radio waves having a desired frequency, namely, to function as an antenna which resonates with radio waves having a desired frequency, by adjustment of at least one of (i) the relative permittivity of the dielectric substance which forms the windshield member3and (ii) the area of an overlap region where the inward flange part21(the first stage flange21aof the bezel2, in this embodiment) and the windshield member3overlap each other.

A method for adjusting the frequency receivable by the bezel2is described below in detail.

As shown inFIG. 4,FIG. 5and so forth, the electronic timepiece100of this embodiment further includes the buffer member4which partially or entirely covers the bezel2.

The buffer member4can be formed of resin, such as a urethane resin.

As described above, in this embodiment, the bezel2is made to function as an antenna. Hence, is preferable that the buffer member4which contacts the bezel2be formed of a nonconductive low-loss (dielectric loss (tan δ)) material in order not to block the function of the bezel2as an antenna.

The electronic timepiece100of this embodiment includes, as the buffer member4, first buffer members4awhich cover portions of the bezel2for 12 o'clock and 6 o'clock in an analog timepiece, a second buffer member4bwhich covers a portion of the bezel2for 3 o'clock in an analog timepiece, and a third buffer member4cwhich covers a portion of the bezel2for 9 o'clock in an analog timepiece.

In each of the first buffer members4awhich respectively cover the portions for 12 o'clock and 6 o'clock in an analog timepiece, two screw holes42to insert screws41are formed.

As shown inFIG. 3, the screws41are inserted from the screw holes42formed in the first buffer members4ainto the holes13formed in the exterior case1via screw holes22formed in the bezel2, so that the bezel2and the buffer member4(the first buffer members4a, in this embodiment) are screwed to the exterior case1.

On the first buffer members4a, at the positions where the operation buttons12(12a) are arranged, holes43to insert the operation buttons12(12a) into the exterior case1are formed.

On the second buffer member4b, at the position where the operation button12(12b) is arranged, a not-shown hole to insert the operation button12(12b) into the exterior case1is formed.

The second buffer member4band the third buffer member4care fixed (screwed) to the exterior case1with screws45, and at the positions where the screws45are inserted, not-shown screw holes are formed.

Configuration of the buffer member4is not limited to that exemplified herein. For example, the buffer member4may be formed to be continuous, not being divided. Further, the buffer member4may entirely cover the bezel2.

Hereinafter, configuration to electrically connect the bezel2with the circuit board71(the antenna circuit mounted on the circuit board71) is described with reference toFIG. 9AtoFIG. 9C.

FIG. 9Ais an important portion enlarged sectional view showing a connection portion where the bezel2is connected with the circuit board71.FIG. 9Bis a perspective view of the connecting member25which connects the bezel2with the circuit board71.FIG. 9Cis an important portion plan view showing a state in which the connecting member25is inserted into the circuit connection hole part15of the exterior case1viewed from the visible side.

As shown inFIG. 9A, between the bezel2and the circuit board71of this embodiment, the connecting member25is arranged.

The connecting member25is a terminal plate formed of a conductive material. Examples thereof include various metal materials. The connecting member25is interposed between the bezel2and the circuit board71, so that the bezel2and the circuit board71are electrically connected with one another.

As shown inFIG. 9B, the connecting member25has: at one end, a connecting tongue piece252having a bezel-side connecting part251which is connected to the bezel2; and at the other end, a connecting leg part254having a circuit board-side connecting part253which is connected to the circuit board71. The connecting member25also has, at both (right and left) sides of the connecting tongue piece252, hook parts255which are bent toward the connecting leg part254.

The connecting member25is formed, for example, by die-cutting and then bending a thin metal plate in such a way as to form the bezel-side connecting part251, the connecting tongue piece252, the circuit board-side connecting part253, the connecting leg part254and the hook parts255. The whole connecting member25has spring properties.

As shown inFIG. 9C, the connecting member25is inserted into the notched part150of the exterior case1, and the pair of the hook parts255is inserted into one of the circuit connection hole parts15from the above (the upper side inFIG. 9Aor the bezel2side), so that the connecting member25is set. Then, from the above the exterior case1, the bezel2is placed, so that the connecting member25is interposed between the bezel2and the circuit board71, and its position is fixed.

InFIG. 9A, the connecting member25in a state of no application of external force thereto is indicated by a two-dot chain line, and the connecting member25in a state of being interposed between the bezel2and the circuit board71and pressed in the up-down direction (the up-down direction inFIG. 9Aor the thickness direction of the exterior case1) is indicated by a solid line.

As shown inFIG. 9A, the connecting member25is arranged between the bezel2and the circuit board71in a state of being pressed and thereby shrinking as a whole. The bezel-side connecting part251is pressed on the back surface (the lower surface inFIG. 9A) of the bezel2, and the circuit board-side connecting part253is pressed on the front surface (the upper surface inFIG. 9A) of the circuit board71.

Into the ground connection hole part16, the not-shown ground terminal is inserted to connect the bezel2to the ground.

In this embodiment, the circuit board71functions as the ground, and one end and the other end of the ground terminal contact the bezel2and the circuit board71, respectively.

The component which functions as the ground is not limited to the circuit board71. If there is another component which functions as the ground, the ground terminal is arranged such that the other end thereof contacts this component as the ground.

In this way, the bezel2formed of a metal material is electrically connected with the circuit board71(the antenna circuit mounted on the circuit board71) and connected to the ground, and consequently can function as an antenna.

Next, the method for adjusting the frequency receivable by the bezel2according to this embodiment is described.

As described above, in this embodiment, at least one of (i) the relative permittivity of the dielectric substance which forms the windshield member3and (ii) the area of the overlap region where the inward flange part21(the first stage flange21aof the bezel2, in this embodiment) and the windshield member3overlap each other is adjusted and set such that the bezel2resonates with radio waves having a desired frequency, namely, such that the bezel2functions as an antenna which resonates with radio waves having a desired frequency.

In general, if radio waves having a low frequency are desired to be received, an antenna is long. However, in the case where the electronic timepiece100having the bezel2which is made to function as an antenna is a watch, it is difficult for a normal bezel, which is provided as an exterior member of a watch, to ensure the antenna length for a low frequency, in terms of its size.

In this embodiment, by a combination of the bezel2and the windshield member3with no change in the size of the bezel2, the resonance frequency of the bezel2is adjusted such that the bezel2can receive radio waves having a desired frequency.

The relative permittivity of the dielectric substance which forms the windshield member3and the frequency have a relationship in which the higher the relative permittivity of the windshield member3is, the lower the frequency of radio waves receivable by the bezel2is.

FIG. 10shows relative permittivity (εr) at 1 MHz and dielectric loss (tan δ×10−4) at 1 MHz of super white glass and sapphire.

As shown inFIG. 10, super white glass has a relative permittivity of 7 and a dielectric loss of 36, and sapphire (synthetic sapphire) has a relative permittivity of 10 and a dielectric loss of 0.001. Hence, to decrease the frequency of radio waves receivable by the bezel2(i.e. to decrease the resonance frequency or resonance point), it is preferable to use sapphire, the relative permittivity of which is higher than that of super white glass, as the material for forming the windshield member3.

The materials shown inFIG. 10are examples and do not intend to limit the material for forming the windshield member3. The material for forming the windshield member3can be appropriately selected and used from materials having a high relative permittivity to a low relative permittivity so as to be suitable for the frequency of radio waves desired to be received by the bezel2.

The bezel2and the windshield member3have, about arrangement, a relationship in which the wider the area of the overlap region where the inward flange part21and the windshield member3overlap each other is, the lower the frequency of radio waves receivable by the bezel2is.

FIG. 11is a schematic view to explain the overlap of the bezel2and the windshield member3.FIG. 12is a graph showing the relationship between the overlap region of the bezel2and the windshield member3and the frequency.

InFIG. 11, “Gd” represents diameter of the windshield member3, “BId” represents inner diameter of the inward flange part21(the first stage flange21a, in this embodiment) of the bezel2, and “Bfw” represents width of a ring-shaped portion where the inward flange part21(the first stage flange21a, in this embodiment) and the windshield member3overlap each other. Further, inFIG. 11, “Ar” indicating a shaded region represents the ring-shaped overlap region where the inward flange part21(the first stage flange21a, in this embodiment) and the windshield member3overlap each other.

FIG. 12shows change in the frequency of radio waves receivable by the bezel2in a case where the inner diameter BId of the inward flange part21shown inFIG. 11is 38.4 mm, and each of the windshield members3having diameters Gd of 39.2 mm (the area of the overlap region Ar is 48.5 mm2), 39.4 mm (the area of the overlap region Ar is 61.1 mm2), 39.6 mm (the area of the overlap region Ar is 73.5 mm2), 39.8 mm (the area of the overlap region Ar is 86 mm2) and 40 mm (the area of the overlap region Ar is 98.5 mm2) is arranged.

As shown inFIG. 12, when the area of the overlap region Ar is small and 48.5 mm2, radio waves having a high frequency of about 1592 MHz can be received, and as the area of the overlap region Ar increases, the frequency of radio waves receivable decreases, and is about 1574 MHz when the area of the overlap region Ar is 98.5 mm2.

Under the above condition, 0.4 mm decrease in the diameter Gd of the windshield member3(i.e. 0.2 mm decrease in the width Bfw of the overlap portion) results in about 10 MHz increase in the frequency of radio waves receivable by the bezel2(resonance frequency).

Hence, to decrease the frequency of radio waves receivable by the bezel2(i.e. to decrease the resonance frequency or resonance point), it is preferable to set the size of the windshield member3and/or the width of the inward flange part21of the bezel2in such a way as to increase the area of the overlap region Ar.

Both of (i) the relative permittivity of the dielectric substance which forms the windshield member3and (ii) the area of the overlap region Ar where the inward flange part21(the first stage flange21aof the bezel2, in this embodiment) and the windshield member3overlap each other may be adjusted.

In this case, forming the windshield member3from a dielectric substance having a high relative permittivity at a size which increases the area of the overlap region Ar allows the bezel2to receive radio waves having a lower frequency.

In contrast, forming the windshield member3from a dielectric substance having a low relative permittivity at a size which decreases the area of the overlap region Ar allows the bezel2to receive radio waves having a higher frequency.

In addition to the region on the back surface of the windshield member3placed on the inward flange part21, the circumferential surface of the windshield member3in the thickness direction also contacts the bezel2.

However, it is considered that the overlap region on the circumferential surface of the windshield member3in the thickness direction does not much affect change in the frequency of radio waves receivable by the bezel2(resonance frequency). Hence, inFIG. 12, no particular consideration is given thereto.

More specifically, for the change in the frequency (resonance frequency), consideration needs to be given to effective relative permittivity, and what is especially important is degree of overlap of the windshield member3on, of the bezel2, a portion where more current flows. Because more current flows near the ground, in this embodiment where the circuit board71serves as the ground, it is considered that more electricity is likely to gather at, of the inward flange part21, a portion close to the center of the ring-shaped bezel2and near the circuit board71.

Hence, in this embodiment, no consideration is given to the overlap region on the circumferential surface of the windshield member3in the thickness direction, andFIG. 12shows only the relationship indicating change in the frequency (resonance frequency) with respect to the overlap region Ar where the upper surface of the inward flange part21contacts the back surface of the windshield member3.

Factors which can adjust the frequency of radio waves receivable by the bezel2are not limited to those described above. The relative permittivity of the windshield member3and the overlap region Ar of the windshield member3and the bezel2may be combined with another/other factor(s) so as to adjust the frequency of radio waves receivable by the bezel2more widely.

For example, in this embodiment, between the upper surface of the inward flange part21and the back surface of the windshield member3, the spacer32is arranged. The higher the relative permittivity of the material forming the spacer32is, the lower the frequency of radio waves receivable by the bezel2(resonance frequency) is.

For example, if PET is used as the material for forming the spacer32as described above, because the relative permittivity of PET is about 3.2, which is relatively low, the resonance frequency tends to be high. Replacement of the material for forming the spacer32with one having a high relative permittivity can promise an effect of making the resonance frequency low.

Further, the thicker the spacer32is, the higher the frequency of radio waves receivable by the bezel2is.

That is, bringing a component having a possible higher relative permittivity in contact with (or to be contiguous with) the bezel2as an antenna can increase the effective relative permittivity, and consequently can produce the same or similar effect as or to that produced by increasing the area of the overlap region Ar where the bezel2and the windshield member3overlap each other.

Hence, giving consideration also to the combination of the thickness of the spacer32and the material for forming the spacer32can more greatly change the frequency of radio waves receivable by the bezel2(resonance frequency).

Further, the further away the connecting member25, which electrically connects the bezel2with the circuit board71, is located from the ground terminal, the higher the frequency of radio waves receivable by the bezel2is.

Hence, appropriate determination about into which circuit connection hole part15and ground connection hole part16, the connecting member25and the ground terminal are inserted, respectively, can also adjust the frequency of radio waves receivable by the bezel2(resonance frequency).

Next, operation of the electronic timepiece100according to this embodiment is described.

In assembling of the electronic timepiece100, first, the dial5is arranged such that its outer edge is placed on the second stage flange21bof the inward flange part21of the bezel2, and the dial5is fixed thereto with the adhesive member54, such as a double-sided tape.

Next, the waterproof ring31is arranged in the first stage flange21aof the inward flange part21of the bezel2along the inner side surface of the bezel2, and also the spacer32is arranged on the upper surface of the first stage flange21a, and the windshield member3is press-fitted into the bezel2from the above.

Next, the first buffer members4a, the second buffer member4band the third buffer member4care attached to the outer side of the bezel2. The first buffer members4aand the bezel2are fixed to the exterior case1with the screws41. The second buffer member4band the third buffer member4care fixed to the exterior case1with the screws45.

Next, the operation buttons12(12aand12b) are attached by being inserted into the holes43of the first buffer members4aand the through holes14of the exterior case1.

Next, the connecting member25is arranged in the notched part150, and the hook parts255of the connecting member25are fitted in and fastened to the circuit connection hole part15. Also, the ground terminal is arranged in the notched part160and fitted in and fastened to the ground connection hole part16.

Next, the housing7housing the battery74and so forth, the circuit board71, the liquid crystal panel55and so forth are arranged in the exterior case1, and the opening in the back surface of the exterior case1is closed by the back cover member8.

In this way, the electronic timepiece100is complete (i.e. assembled).

In the assembled state, the bezel2is electrically connected with the circuit board71via the connecting member25. At the time, between the bezel2and the circuit board71, the connecting member25, which has spring properties, is pressed and thereby shrinks. This can ensure a sufficient contact pressure, and consequently can surely connect the bezel2and the circuit board71with one another. Further, in the assembled state, the bezel2is connected with the circuit board71, which functions as the ground in this embodiment, via the ground terminal.

In this way, the bezel2formed of a metal material can function as an antenna.

Further, for example, if signals from GPS satellites are desired to be received, (i) the relative permittivity of the material for forming the windshield member3arranged in the bezel2is given consideration and/or (ii) the area of the overlap region Ar of the bezel2and the windshield member3is adjusted such that the bezel2can resonate with radio waves having a desired frequency, for example, 1575.42 MHz. In this way, the bezel2as an antenna can receive radio waves having a desired frequency.

Reception of radio waves having a desired frequency enables acquirement of accurate time information, position information and so forth, and consequently enables correction of, for example, time to be displayed by the electric timepiece100to right one as needed.

As described above, according to this embodiment, the electronic timepiece100includes: the cylindrical exterior case1in which the circuit board71where the antenna circuit is formed is housed; the bezel2which is formed of a metal material to be ring-shaped, includes the inward flange part21that projects from the inner side surface of the ring-shaped bezel2toward the center of the ring-shaped bezel2, is arranged on the outer upper side of the exterior case1, and is electrically connected with the circuit board71; and the windshield member3which is formed of a transparent dielectric substance, arranged in the bezel2, and supported by the inward flange part21, wherein the bezel2is configured to function as an antenna which resonates with radio waves having a desired frequency by adjustment of at least one of (i) the relative permittivity of the dielectric substance which forms the windshield member3and (ii) the area of the overlap region where the inward flange part21and the windshield member3overlap each other.

That is, the frequency of radio waves receivable by the bezel2(resonance frequency) can be set with no change in the size or shape of the bezel2.

Hence, limitations in design as a timepiece can be suppressed, and radio waves having a desired frequency can be received well while design quality is maintained.

Further, because the bezel2is configured to function as an antenna which resonates with radio waves having a desired frequency by appropriate setting of the relative permittivity of the windshield member3, the area of the overlap region Ar of the inward flange part21and the windshield member3and/or the like, the bezel2as an antenna can receive the radio waves having the desired frequency. This can realize the electronic timepiece100which can acquire accurate time information and position information.

Further, in this embodiment, the frequency of radio waves receivable by the bezel2as an antenna can be set at a lower frequency by the relative permittivity of the dielectric substance which forms the windshield member3being higher.

Further, in this embodiment, the frequency of radio waves receivable by the bezel2as an antenna can be set at a lower frequency by the area of the overlap region Ar where the inward flange part21and the windshield member3overlap each other being wider.

Further, the bezel2of this embodiment is connected with the circuit board71via the connecting member25.

That is, the bezel2, which functions as an antenna, is connected with the circuit board71directly by the connecting member25. This stabilizes their connection state and can keep excellent antenna characteristics as compared with a case where an antenna is connected with a circuit board indirectly by capacitive coupling.

Further, in this embodiment, the radio waves having the desired frequency receivable by the bezel2, which functions as an antenna, include radio waves transmitted from satellites.

The bezel2is configured to resonate with radio waves having, for example, a frequency of 1575.42 MHz by appropriate setting of the size, shape, forming material and/or the like of the bezel2, and consequently can receive radio waves transmitted from GPS (Global Positioning System) satellites and radio waves transmitted from QZSS, which are quasi-zenith satellites of Japan. This allows the electronic timepiece100to make use of time information and position information contained in these radio waves.

One or more embodiments of the present invention are described above. Needless to say, however, the present invention is not limited to the embodiment(s) and can be modified in a variety of aspects without departing from the scope of the present invention.

For example, the configuration to connect the bezel2with the circuit board71is not limited to that exemplified in the embodiment. For example, a coaxial cable or a feed pin may be used therefor.

Further, the electronic timepiece100may include a solar panel.

In this case, the solar panel is also arranged at a position relatively close to the bezel2, which functions as an antenna. Hence, it is preferable that consideration be also given to, for example, the relative permittivity of the material for forming the solar panel so as to be suitable for the frequency of radio waves desired to be received by the bezel2.

Further, in the embodiment, the circuit board71serves as the ground. However, the ground to which the bezel2, which functions as an antenna, is connected is not limited to the circuit board71.

For example, if the dial5is formed of a metal material or the like, the dial5may function as the ground. In this case, one end and the other end of the ground terminal are connected to the bezel2and the dial5, respectively.

Further, if the electronic timepiece100includes the solar panel as described above, the solar panel may function as the ground.

Further, in the embodiment, the electronic timepiece100includes the digital display constituted of the liquid crystal panel55or the like. However, the display arranged in the electronic timepiece100is not limited to such a digital display. For example, the display may be an analog display having hands or the like, or may be an analog-digital display.

Further, in this embodiment, the electronic timepiece100is a watch, but not limited thereto. The electronic timepiece of the present invention is applicable to a wide range of devices as far as they can be used as a timepiece.

For example, the electronic timepiece of the present invention may be applied to various devices including a pedometer, an altimeter and a barometer.

In the above, one or more embodiments of the present invention are described. However, the scope of the present invention is not limited thereto, and includes the scope of claims below and the scope of their equivalents.