Abstract:
A wristworn device comprising a radio communication device for receiving from and/or transmitting signals to a radio communication device external to the wristworn device. In at least one embodiment, the casing comprises a metallic watchcase having a slot, and wherein the watchcase is electrically coupled to the radio communication device to function as the antenna. In another embodiment, a metallic loop is provided in the casing proximate the watchcase, wherein the metallic loop is electrically coupled to the radio communication device to function as the antenna and the watchcase comprises a slot and functions as an element for the reception and/or transmission of electromagnetic radiation. In a third embodiment, the metallic watchcase does not have a slot and the watchcase is electrically coupled to the radio communication device to function as the antenna.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates generally to antennas, and in particular, to an improved antenna for a wristworn device having signal transmitting and/or receiving capabilities. In exemplary embodiments, the wristworn device is a timepiece such as a wristwatch, but, as will become quite clear below, a timepiece or wristwatch is only by way of example and not limitation. In particular, the invention is primarily directed to improved signal transmission and reception within a metal casing, such as a casing for a timepiece. 
   The prior art is full of examples of antennas associated with wristworn devices, such as wristwatches. As would be well known to those skilled in the art, loop antennas are particularly advantageous due to their size and directivity, as it is well known that a loop antenna is desirable since it has a geometry that essentially “pulls in” signals from 360 degrees (i.e. from all different azimuths and orientations). For example, U.S. Pat. Nos. 5,072,231; 6,104,354; 6,028,555 and 6,154,177 are but just a few examples of devices incorporating loop antennas for signal reception and transmission. While these arrangements may have been satisfactory for their intended uses, they all are perceived to be deficient in various respects. 
   The use of loop antennas for signal reception and transmission has been found to be particularly desirable in devices, such as timepieces. However, use of a loop antenna in a metal case, such as a watch casing, has been found to have drawbacks and to be less than optimal, typically because of the poor performance due to the shielding of the antenna by the metal case itself. Additionally, electro-static discharge (ESD) is also a known problem when using a metal casing. 
   Introducing a slot in the case to improve signal reception or transmission is known. For example, the inventor is aware of at least one device that had therein an RFID transmitter/receiver, which incorporated a slotted casing. However, this known example utilizes a coil antenna with a ferrite core, which doesn&#39;t provide a desirable distance communication range. Moreover, the use of coil antennas in such devices are limited to short range (e.g. 1–2 feet) communications, which are less than desirable in the communications contemplated by the present invention. 
   With all of the known obstacles related to shielding and performance of a loop antennas in a metal casing, it is believed that the prior art designs have been less than effective in incorporating a loop antenna into a device having a metal casing. Even more remote is the idea of using the metal casing itself as the loop antenna. However, as discussed below, the present inventor has recognized that when a slotted casing is used as the actual antenna or when the loop is placed underneath and the case is used a “re-radiator,” signal reception/transmission performance is significantly improved. 
   OBJECTIVES AND SUMMARY OF THE INVENTION 
   Therefore, it is generally an object and advantage of the present invention to provide an improved antenna arrangement for a device comprising a metal casing. 
   It is still a further object and advantage of the present invention to provide an improved antenna arrangement for a wristworn device having improved signal transmission and reception functionality. 
   It is another object and advantage of the present invention to provide an improved antenna arrangement for a wristworn timepiece that incorporates therein a receiver, transmitter and/or transceiver. 
   It is yet another object of the present invention is to provide an improved antenna arrangement for a wristworn device that reduces the number of components of the device yet provides satisfactory or even improved signal reception and/or transmission. 
   Yet another object and advantage of the present invention is to provide an improved antenna arrangement that reduces ESD. 
   Further objects and advantages of this invention will become more apparent from a consideration of the drawings and ensuing description. 
   The invention accordingly comprises the features of construction, combination of elements, arrangement of parts and methodology of construction that will be exemplified in the disclosure hereinafter set forth, and the scope of the invention will be indicated in the claims. 
   To overcome the perceived deficiencies in the prior art and to achieve the objects and advantages above and below, the present invention, generally speaking, is directed to a wristworn device comprising a radio communication device for at least one of receiving signals from and transmitting signals to a radio communication device external to the wristworn device. 
   In a first embodiment, the wristworn device comprises a casing comprising a metallic watchcase, a crystal that seals a first end of the watchcase and a case back that seals a second end of the casing; controller means disposed in said casing and operatively coupled to the radio communication device, and wherein the watchcase comprises a slot, and wherein the watchcase is electrically coupled to the radio communication device to function as the antenna for at least one of reception or transmission of signals for the radio communication device. 
   In a second embodiment, the wristworn device comprises a casing comprising a metallic watchcase, a crystal that seals a first end of the watchcase and a case back that seals a second end of the casing; controller means disposed in said casing and operatively coupled to the radio communication device, a metallic loop provided in the casing proximate the watchcase, wherein the metallic loop is electrically coupled to the radio communication device to function as the antenna for at least one of reception or transmission of signals for the radio communication device; and wherein the watchcase comprises a slot and functions as an element for the reception and/or transmission of electromagnetic radiation. 
   In a third embodiment, the wristworn device comprises a casing comprising a metallic watchcase, a crystal that seals a first end of the watchcase and a case back that seals a second end of the casing; controller means disposed in said casing and operatively coupled to the radio communication device, and wherein the watchcase is electrically coupled to the radio communication device to function as the antenna for at least one of reception or transmission of signals for the radio communication device. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above set forth and other features of the invention are made more apparent in the ensuing Description of the Preferred Embodiments when read in conjunction with the attached Drawings, wherein: 
       FIG. 1  is an exploded perspective view of the present invention in accordance with a first embodiment; 
       FIG. 2  is an exploded perspective view of the present invention in accordance with a second embodiment; and 
       FIG. 3  is an exploded perspective view of the present invention in accordance with a third embodiment. 
   

   Like reference numbers are used for like parts, although not every feature is numbered in each figure. 
   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Reference shall be first made  FIG. 1  and the following disclosure, which depicts and discloses a wristworn device, generally indicated at  10 , constructed in accordance with a first embodiment of the present invention. 
   In a preferred embodiment, device  10  is a wristworn device, and preferably a timepiece. However, as indicated above, device  10  need not be limited to a timepiece or wristwatch, and may be a variety of other devices, such as a heart rate monitor, glucose monitor or other communication device, examples of which are disclosed in Published Application Serial No. 2004/0233788 (the &#39;788 Published Application), which is hereby incorporated by reference in its entirety. 
   As illustrated in  FIG. 1 , device  10  preferably comprises a metal watchcase  15 , a glass or plastic transparent watch crystal  20  that allows viewing of a watch dial  22 , a case back  25  and a watch movement generally indicated at  30  that contains the electrical and mechanical mechanisms for timekeeping, including hand movement. A battery (not shown) is also provided. Watch dial  22  provides for the display of information in an analog or digital fashion. An audible indicator may also be provided. As will be true for all the figures, it should be apparent that dial  22  is “under” the crystal  20  and that controller means  30  (i.e. and the movement) is preferably “under” the dial  22 . 
   As disclosed in the aforementioned &#39;788 Published Application, an “analog fashion” of display typically comprises the use of hands, while a “digital fashion” display typically consists of an LED, LCD, a dot matrix or a variety of the new display technologies that display information without the use of indicator hands. 
   As is also well-known in the art, controller means/movement  30  for device  10  (e.g. a watch movement”) usually comprises a printed circuit board that contains a microcontroller, and/or discreet semiconductor devices and/or an application specific integrated circuit (ASIC) to perform timekeeping and communications functions. Controller means/movement  30  may also comprise one or more (e.g. stepping) motors for the rotation of the indicator (e.g. hour/minute, display) hands. Similarly, the controller means or “movement” may comprise a digital display for the display of data in the “digital fashion” format. In either “movement,” a battery (not shown) and frame (not shown) are provided to hold the mechanism together as one unit. Disclosure of a suitable controller and other hand movement components for the present invention is provided in the &#39;788 Published Application and incorporated by reference herein. To be clear, the phrase “controller means” is intended to comprehensively encompass all the circuitry, software and hardware to communicate with the communication device  50  which will be hereinafter disclosed, which in turn communicates with the external communication device. Moreover, the “controller means” is intended to also include all the hand rotation signaling and functionality to carry out the objectives set forth herein and made apparent hereby. 
   In accordance with the present invention, device  10  comprises a radio communication device, generally indicated at  50 , such as a transmitter, a receiver and/or a transceiver. Device  50  is preferably mounted on the printed circuit board and usually interfaces to the microcontroller (not shown) of the controller means  30 . Data is transferred to or from radio communication device  50  for the purpose of data display, data storage and/or control, all as is well known in the art. 
   Metal watchcase  15  includes a slot  16  in the circumference which creates a broken circular loop  17 . Slot  16  is preferably filled with a nonmetallic material  18 , such as plastic by injection molding, to minimize water and debris infiltration into the casing  15 . For aesthetic reasons, slot  16  may be provided proximate the crown. In the preferred embodiment, the loop is in fact circular, but as would be understood by those skilled in the art, the loop can also be other shapes such as a square broken loop in a device with a square watch case. 
   The break in metal watchcase  15  that creates a circular loop forms an electric field type loop antenna that is connected to radio communication device  50 . To maximize the exchange of electromagnetic energy between the antenna  17  thus formed and radio communication device  50 , a tuning network  55  comprising inductors and/or capacitors, as would be known to those skilled in the art, is preferably placed between antenna  17  and device  50 . 
   As can thus be seen in this first embodiment, the novelty of loop antenna  17  is the use of metal watchcase  15  therefor. The loop configuration created by slot  16  in the casing creates a form factor that efficiently radiates energy and receives radiated energy. 
   Metal in proximity of the loop  17  depending on its orientation and continuity can affect the ability of the performance of antenna  17 . Since any deviation from the loop form factor such as the addition of a metal case back would detract from the ability of antenna  17  to radiate waves or receive radiated waves, case back  25  preferably comprises a form factor that maintains the loop configuration. This is achieved by using a non metallic case back such as glass, ceramic and/or plastic which do not significantly impede radiation. However, the case back  25  can also be comprised of a nonmetallic material in the center of the case back and a metallic material on the perimeter of the case back, effectively maintaining the loop configuration. Likewise, dial  22  should also be configured from nonmetallic material to minimize any negative effects on transmission or reception. Again, for purposes of simplicity, no significant detail is provided for dial  22 , although it should be clear that conventional dials with, for example, numerical indicia, are contemplated herein. 
   Reference is now made to  FIG. 2  in connection with the following disclosure, which depicts and discloses a wristworn device, generally indicated at  100 , constructed in accordance with a second embodiment of the present invention. 
   In this preferred embodiment, device  100  is likewise preferably a wristworn device, and preferably a timepiece. However, as indicated above with respect to device  10 , device  100  need not be limited to a timepiece or wristwatch, and may be a variety of other devices, such as those disclosed above. 
   Similar to device  10 , device  100  also preferably comprises metal watchcase  15 , glass or plastic transparent watch crystal  20 , case back  25 , a dial  22 , a controller means/watch movement  30  such as that disclosed above, and radio communication device  50  that is coupled to the controller means. Again, the controller means may comprise a controller such as that disclosed in the aforementioned &#39;788 Published Application, the subject matter of which is incorporated herein by reference. The design and construction of the foregoing features are similarly constructed. For example, watchcase  15  of this second embodiment also preferably comprises a slot  16  in the circumference which creates a broken circular loop, with slot  16  also preferably filled with a nonmetallic material  18 , such as plastic, to minimize water and debris infiltration into the casing. Again, while the preferred shape of the loop is circular, this is by example and not limitation. 
   This second embodiment most significantly differs from the first embodiment by its inclusion of a metallic loop  60  placed within the circumference of metal watchcase  15 . This metallic loop  60  forms an electric field type loop antenna and is electrically coupled to radio communication device  50 . In this implementation, loop  60  acts as the primary antenna, and metal watchcase  15  acts as a re-radiator element. Electrical energy is efficiently transferred from inner loop  60  to metal watchcase  15  because the two loops, namely loop  60  and watchcase  15  are in close proximity to each other and therefore closely coupled. 
   To maximize the exchange of electromagnetic energy between metallic loop  60  and radio communication device  50 , a tuning network  55 , comprising inductors and/or capacitors, is placed between metallic loop  60  and device  50 . Metal watchcase  15  can be tuned with inductors and/or capacitors or be left un-tuned depending on the desired antenna characteristics particular for each design. 
   As will thus be appreciated, this second embodiment provides for the use of metal watchcase  15  as a re-radiator, along with metallic loop  60  as the antenna. The loop configuration created by slot  16  in watchcase  15  and metallic loop  60  creates a form factor that efficiently radiates energy and receives radiated energy. 
   As with the first embodiment, metal in proximity of loop  60  depending on its orientation and continuity can affect the ability of its performance as an antenna. Thus, as with the first embodiment, case back  25  comprises a form factor that maintains the loop configuration. Here again, this may be achieved by using a non metallic case back such as glass, ceramic and/or plastic which do not significantly impede radiation. On the other hand, it can likewise also be comprised of a nonmetallic material in the center of the case back and a metallic material on the perimeter of the case back, thereby effectively maintaining the loop configuration. 
   In yet an alternative to this second embodiment, case  15  may be non-metallic (e.g. plastic). 
   Reference is now made to  FIG. 3  in connection with the following disclosure, which depicts and discloses a wristworn device, generally indicated at  1000 , constructed in accordance with yet a third embodiment of the present invention. 
   In this preferred embodiment, device  1000  is likewise preferably a wristworn device, and preferably a timepiece. However, as indicated above with respect to device  10  and  100 , device  1000  need not be limited to a timepiece or wristwatch, and may be a variety of other devices, such as those disclosed above and in the &#39;788 Published Application. 
   Similar to devices  10  and  100 , device  1000  also preferably comprises a metal watchcase, glass or plastic transparent watch crystal  20 , a dial  22 , a case back  25 , controller means/watch movement  30  such as that disclosed above, and radio communication device  50  coupled to controller means  30 . The design and construction of the foregoing features are similarly constructed. 
   This third embodiment most significantly differs from the foregoing first two embodiments by providing a continuous metal case  150  (i.e. there is no slot as defined and illustrated above, provided in the watchcase). Watchcase  150  may be circular or square, by way of example and not limitation. 
   In this embodiment, radio communications device  50  is coupled/fed into two points of the metal watchcase  150 . By optimum selection of these two feed points with respect to resistance and reactance of the watch case at the frequency or range of frequencies at which radio device  50  operates, watchcase  150  becomes an electric field type loop antenna. To maximize the exchange of electromagnetic energy between the antenna  150  and radio communication device  50 , a tuning network  55  consisting of inductors and/or capacitors is coupled therebetween. 
   The loop configuration created by the selected feed points and tuning network creates a form factor that efficiently radiates energy and receives radiated energy. The unique approach with this third embodiment is the optimum match of radio device  50  to metal watchcase  150 , which becomes a radiating element. 
   Similar to the first two embodiments, metal in proximity of the loop depending on its orientation and continuity can affect the ability of the loop performance. And, since any deviation from the loop form factor such as the addition of a metal case back would detract from the loop&#39;s ability to radiate waves or receive radiated waves, case back  25  is comprised of a form factor that maintains the loop configuration. This is achieved most easily by using a non metallic case back such as glass, ceramic and/or plastic which do not significantly impede radiation. It can also be comprised of a nonmetallic material in the center of the case back and a metallic material on the perimeter of the case back, effectively maintaining the loop configuration. Here again, dial  22  is preferably configured from nonmetallic material to minimize any negative effects to transmission or reception. 
   It can thus be seen that the present invention provides an improved antenna arrangement for a wristworn device having improved signal transmission and reception functionality. Further, the present invention provides an improved antenna arrangement for a wristworn timepiece that incorporates therein a receiver, transmitter and/or transceiver. Further, the present invention provides an improved antenna arrangement for a wristworn device that reduces the number of components of the device yet provides satisfactory or even improved signal reception and/or transmission. In addition, the present invention provides an improved antenna arrangement that reduces ESD. 
   It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in the above constructions without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. 
   It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention described herein and all statements of the scope of the invention which as a matter of language might fall therebetween.