FI124133B - Electronic wearable device - Google Patents

Description

ELECTRONIC WEARING DEVICE

Background of the Invention

Field of the Invention 5

The present invention relates to wearable electronic devices. The invention is particularly directed to a wrist-mounted device, for example a wrist computer having an antenna for wireless connection to other electronic devices. The invention further relates to a method for manufacturing an antenna for wearable devices.

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Description of the Related Art

Antennas have been assembled on wrist computers for some time to enable wireless data transmission to and from the device. However, the connection of the antenna to the wearable device is a challenging task due to size limitations, the large number of electronic components close to each other and the proximity of the human body.

US 2002/0098807 describes a wrist unit having an integrated loop antenna. The loop is flush with the other electronic circuits 20 of the device so that some of the electronics are located inside the antenna loop, whereby the electronic circuits function as the antenna ground plane.

Loop type antennas are also described in U.S. Patents 5,768,217, 5,926,144 and 6,278,873.

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Slit antennas can be used instead of conventional loop or dipole antennas because they can generate and detect alternating electromagnetic fields. The field produced by the slot antenna is of a very similar shape to the O-w field produced by a similarly sized dipole antenna, except that the polarization direction of the electric and magnetic fields 2 30 nat is interchanged.

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US 6,282,433 describes a cellular telephone having a slot antenna for short range communication. The antenna is used to connect directly to remote computers or to a local area network (LAN).

U.S. Patent 5,699,319 describes a wristwatch with an internal dipole antenna or slit antenna. The antenna is housed between two housings, one of which forms the outer face of the clock and the other contains the electronic and mechanical parts of the device. The antenna is formed as a separate element by applying a conductive material to the dielectric to form a suitable antenna pattern.

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A significant disadvantage of the wearable devices described above is that because the antenna is located deep within the device housing, conductive materials cannot be used in the device housing due to the resulting attenuation of the signal. Therefore, the described structure cannot be used in metal enclosed or metal coated devices. In addition, the antenna requires a large amount of space inside the device 15 and is easily coupled to the device circuits, whereby the location of the parts must be made taking into account the proximity of the antenna.

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate some prior art problems and to provide a wearable device having a novel antenna structure.

In particular, it is an object of the invention to provide a device comprising an antenna structure suitable for devices having electrically conductive housings, such as metallic or metallic housings.

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Thus, the invention is based on the idea of integrating the slit antenna into the housing g (outer housing) of the device, which slit antenna is electrically formed as part of the housing

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as a leader. Such a device generally comprises a radio unit within the insertion zone defined by the casing, which is electrically connected to the slot slot.

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The slot may be formed in the form of an opening formed in the conductive material applied to the device casing or in the conductive material casing. A particularly advantageous solution is achieved if the slot antenna is at least partially located on the outer surface of the casing.

More particularly, the invention is characterized by what is stated in the characterizing parts of claims 1 and 2.

The method of the present invention is essentially characterized by what is said in the characterizing part of claim 12.

The invention provides considerable advantages. In particular, the invention allows the use of a partially or wholly conductive sheath wirelessly in a wearable device that communicates without significant loss of signal due to the sheath. In addition, the slot antenna housed in the outer casing is easy to fabricate and has relatively poor contact with other electronic and conductive parts of the device due to its position on the side. The cover 15 acts as a conductive cage, allowing the antenna to radiate mainly outside the device.

The slot may be formed into a metal casing during the manufacturing of the casing. Typically, such lids are formed of a single piece of metal, whereby slot formation would only be a minor sub-step of this step. In addition, due to the antenna, no additional steps would be required during the assembly phase of the device. Thus, such a solution would not require any complicated mechanical or electrical arrangements within the device, whereby the number of components and further the size of the device can be kept small. The efficient use of the device housing as a radiating element also provides relatively free hands to place other components inside the device.

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δ 25 c \ j c \ j The positioning of the antenna in the outer housing of the device allows the effective size o of the antenna to be increased and thus longer wavelengths to be used than if the antenna were positioned inside the device. In addition, the directivity of the radiation can be adjusted by the three-dimensional structure of the conductive portions of the casing, co 30 o For the purposes of this document, the term "gap" means an elongated recess, especially 00 elongated aperture in the conductive material or materials in the casing electromagnetic radiation at a desired frequency and band. The gap may be open or filled with an insulating material such as a polymer.

In the text above and below, the terms "cover" and "outer casing" are used interchangeably and refer to parts or units arranged (in the assembly zone) to protect or secure internal components such as electronic circuits, user interface elements, such as buttons and screens, to give the device a look, or to allow it to be attached to a bracelet, for example. Typically, these parts or units are at least partially visible from outside the device. Hereby, the cover or housing may be formed of one or more parts. Preferably, the assembly zone is in the form of a space or recess within which at least a portion of the electronic circuits of the device can be located.

The invention will now be described in more detail with reference to the accompanying description and the accompanying drawings.

Brief Description of the Drawings

Fig. 1 is a schematic perspective view of a first preferred embodiment of the device of the present invention with a slot formed at the edge of a fully conductive cover body.

Figure 2 shows a second preferred embodiment m of the device according to the present invention in a schematic perspective view with a gap formed between the body main body 25 and the conductive ring attached to the upper part of the body main body.

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Fig. 3 shows a third preferred embodiment of the device according to the present invention in a schematic perspective view with the gap formed in the casing.

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'Into a dangerous film or coating.

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Fig. 4 is a diagrammatic sectional view of the housing and assembly zone of the device of the present invention, viewed from above.

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DETAILED DESCRIPTION OF THE INVENTION Devices and antennas according to embodiments described herein may be used for communication with remote devices, such as a heart rate monitor belt 5 (or other separate life-sensitive transmitter), speed and / or distance-measuring pedometer or and a GPS receiver (stand-alone position transmitter) or an environmental sensor that sends location information to the wrist unit. In addition, the device may communicate with another compatible wrist unit or a remote computer with a suitable adapter, a wireless network such as a local or wide area network, Bluetooth applications, or, for example, sports timing or performance monitoring applications. The antenna can be used to receive Global Positioning System (GPS) signals or used in a cellular network. Typically, the device is capable of communicating with UHF or microwave region 11a. The illustrated antenna structure 15 enables high-quality connections at a frequency of about 2.4 GHz, for example, used in Bluetooth-enabled communications.

The slot antenna may serve as a transmitting antenna, receiving antenna or transceiver antenna, depending on the intended use of the device. In this case, the radio unit may comprise electrical transmission means (excitation means), reception means or both. Your device may be equipped with Bluetooth compatible signal and / or data processing units that are connected to or included in the radio unit.

The device illustrated in Figures 1-3 preferably comprises a main unit 10, 20, 30 and a bracelet. The main unit 25 includes a jacket having a recessed slot antenna and electronic components contained in the jacket. Typically, the casing comprises a cylindrical peripheral zone on which the slot antenna is formed. In this case, the antenna is typically curved in shape, in particular arcuate. The main unit is typically fitted with a display or pointer □ - 13, 23, 33, typically in a recess or aperture on the top surface of the main unit, co 30m. Figure 4 illustrates how the top 401 also typically comprises a base plate 424 which

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seals the structure from the opposite side to the display board. The mechanism of the device, i.e. electronic components 422, internal wiring 428, and possibly also mechanical parts (not illustrated) are typically accommodated in space 6 426 of inner surface 415 of casing 401, although some or all electronic parts may also be embedded in outer material 415 ).

The slot 402 is preferably mapped to the edge or frame of the cover 401 such that it extends longitudinally along the shape of the periphery of the cover 416 in a substantially lateral plane (i.e., substantially parallel to the plane of the pointer of the device). The slot 412 may also be shaped such that its considerable dimension is also perpendicular to this plane. Slot 412 may be formed on the display panel side of the device, whereby the display panel portion is to be understood as part of the outer housing.

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Generally, the slot is limited in its narrower direction by the first leading edge 15, 25, 35 and the second leading edge 16, 26, 36. The first edge 15, 25, 35 is opposite the second edge 16, 26, 36 such that the slot 12, 22, 32 or recess) is formed between the boundaries. Preferably, the slot has a constant width. The edges are interconnected by conductive end portions 15, 17, 18; 27, 28; 37, 38 which form the edges of the gap. The length of the gap is determined by the distance between the edges when traveling along the gap. In the case of a recess type slot, the edges are also joined together by means of the bottom of the slot. The base is preferably formed of an insulating material.

The gap is preferably at least, typically substantially equal to λ / 2, where λ is the wavelength of electromagnetic radiation. The slot width may be substantially smaller than the wavelength. Therefore, the wrist unit slot antenna is best suited for UHF and microwave applications.

Because of the typically curved shape of the slot, the slot length is between the two end portions

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o 25 linear distances are not equal. This means that the phase difference between the electromagnetic signal passing through the slot and the phase difference between electromagnetic fields between the end portions is different, whereby the antenna is not optimally fed by the electromagnetic field (or the antenna does not radiate optimally during transmission). According to a preferred embodiment

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the gap is dimensioned such that the phase difference of the electromagnetic field between the end portions is less than 50%, especially less than 40%, most preferably less than 25%, than the phase difference of the electric signal in the gap.

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According to the first embodiment shown in Figure 1, the casing 11 is substantially entirely made of conductive material, wherein the gap 12 is made directly on the casing. The slot 12 may be an opening having a length relative to the desired wavelength, at the edge of the cover 11. The longitudinal edges of the slot 12 are denoted by reference numerals 15 and 16 and the transverse edges by the reference numerals 17 and 18. The slot 12 can be formed simply by forming a cut in the casing material, for example by sawing, drilling or cutting.

According to another embodiment depicted in Figure 2, the cover 21 comprises at least two separate portions 24, 29 (slit-forming means) which are joined together to form a slit 22 between the slots 22. A particularly advantageous embodiment is achieved by providing a first edge 25 and 28 is formed by a second edge 26 in the form of a second topsheet 24, for example as a separate conductive plate, ring, rod or the like to the first topsheet 29. The second topsheet may be a specific element of the pointer portion of the device, e.g. which is used to attach a glass, window 15 or screen to the device. The electrical contact of the plate or ring to the first casing must be ensured by sufficient compression of the parts and / or by the use of a suitable contacting agent. The slot-forming members 29, 24 can also be secured to each other by screws 27, 28, whereby the distance of the screws determines the length of the slot, i.e. forming the ends of the slot. More generally, separate contact members 27, 28 may be provided between the first and second cover portions 20 29, 24, which contact members define the gap length. This embodiment provides a sturdy structure in which conventional portions of the device can be used to form a slot 22 in a novel manner.

According to a third embodiment illustrated in Figure 3, the casing 31 is partially fabricated

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25 of the first material 34 and partially of the second material 39 (or a plurality of first materials and second materials). A gap is formed in the portion 39 of the second material of the casing, and every other material is electrically conductive. The second material may be a sheet, film, or x foil, which is preferably adhered to the outer surface of the casing. In Figure 3, slot 32 is formed

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The narrow film 39 applied to the surface of the first material portion 34 may also be substantially completely coated with the second material into which the slot 32 is formed. This embodiment enables a slot antenna

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forming also in devices having, for example, plastic-insulated housing (insulating portion 34 of the first material). A portion of the second material of the coating may be applied to the first material by, for example, conventional metallization techniques, laminating, gluing, vaporizing, hugging, pouring or immersion. If the slot is not already formed at the application stage of another material, it may be formed by removing the conductive material, for example by mechanical machining or etching. According to one embodiment, the conductive material, the etching compound, or both, is applied to the lid in a printing process.

The main embodiments described above and described in the drawings may also be freely combined to produce other various enclosures and slit structures.

According to a further embodiment, the gap, i.e. the elongated recess, in particular the opening, is filled with insulating material to make the coating water and dustproof. This is especially important if the gap is tracked in the form of a complete opening in the housing.

The geometry of the slot and the casing can influence the coverage and directionality of its 15 fields. The slot orientation determines the general direction of the radiation field, and the most effective direction (best coverage area) is typically normal to the plane (surface) defined by the outer edges of the slot. The conductive material in the vicinity of the slot enhances the field outside the casing while reducing the connection of the interior of the device to the field.

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We have found that the shape of the device casing can be effectively used to provide the desired field coverage. In some applications, it is advantageous to tilt the slot so that the best coverage area is formed by the curve as seen upward from the lateral plane, thereby also improving coverage on the front of the device and weakening the connection of the antenna to the device. In such solutions, the cover of the device may be shaped so that it is inclined towards the display board. Thus, the slot automatically locates into the overlay in the correct position. This embodiment may conveniently be combined with all of the above-described superstructure and slit structures.

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According to a preferred embodiment, the corresponding

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o the first and second terminals respectively. The first and second terminals are used for electrical tuning of the antenna or for reading the antenna signal. The terminals are electrically connected to the conductive portions of the casing to achieve the desired oscillation state of the antenna. Figure 4 illustrates the electrical connection between radio unit 420 and antenna 402 by wires 411 and 412. Typically, the terminals are located symmetrically on each side of slot 402 in proximity to its edges substantially in the center of its length, as shown in Figure 4.

The first and second terminals of the antenna 402 are typically connected by means of a suitable coupling member or pair of coupling members 411, 412 to a radio unit 420 located inside the device. Thereby, for example, a coaxial or twisted pair transmission cable may be arranged between the radio unit 420 and the terminals. If necessary, the transmission cable may have balancing properties or a separate balancing transformer (as desired). In some embodiments, the radio unit 420 may be positioned at a position relative to the terminals of the antenna 420 such that it can be directly connected to the terminals, i.e. without a separate transmission cable. Other electronic components may also be present, for example, a (pre) amplifier coupled to the antenna 402 and / or radio unit 420. Also, an electrical ground plane in the form of a conductive plate may be arranged in the vicinity of the gap inside the casing.

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Typically, the wearable device also comprises a timer unit, a microprocessor and a memory unit within the housing. A sensor or a plurality of sensors, such as ambient sensors, acceleration sensors, alignment sensors, proximity sensors, and frame sensors, operatively coupled to each other and eventually to the slot 20 antenna, may be provided inside or outside the housing to transmit data from the sensor. The enclosure of the device can shield the electronics inside the enclosure from harmful electrical and magnetic fields and at the same time act as an efficient antenna for transmitting data in the desired frequency range.

The wrist unit according to the embodiments described above has many uses.

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As will be appreciated by one of ordinary skill in the art, establishing a data connection with, for example, a computer or other similar device enables any data transfer between the devices.

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The above-described embodiments can be used in sports-related applications, where durable, preferably metal-shell wrist computers are becoming more common. The device can be used both o during and after training to transfer and analyze data.

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Local network connectivity, both Bluetooth-enabled and dedicated, can be easily found in a variety of sports. For example, in running, cycling, walking or racing, a data link to a wrist unit and / or wrist unit can be established for timing and to inform all competitors of the competition situation. In orienteering, the device can be used as part of a competition tracking system. In point scoreboards, such as golf and tennis, the device can be operated either by directing the points entered by the user to other players or by transferring to the player the latest competitive information. In all sports, the device can be used as a lightweight data transfer unit to transfer data between the athlete and his coach during exercise and to transfer performance-related data to external data processing equipment.

As will be apparent to one skilled in the art, multiple slots, possibly of different sizes or directions, and intended for various purposes, may have been embedded in a single device.

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Claims (13)

An wrist-worn electronic device comprising: - an outer shell (401) defining an assembly zone (426), and a radio unit (420) within the assembly zone, wherein the outer shell is at least partially made of conductive material, characterized in that: an integrated slit antenna (402) formed in its conductive material, the antenna being electrically connected to said radio unit, and - the device being adapted to communicate with the outer casing by means of a separate life sensitive transmitter, separate motion sensitive transmitter, separate position tracking transmitter or . An electronic device worn on a wrist, comprising: - an outer shell (401) defining an assembly zone (426), and - a radio unit (420), a timer unit, a microprocessor and a memory unit within the assembly zone, the outer shell being at least partially made of conductive material. the combination comprising: - an outer casing comprising an integrated slot antenna (402) formed in its conductive material, the antenna being electrically connected to said radio unit, and - the device further comprising at least one sensor, the sensor, timer unit, mikes 25 and connected to each other and the slot antenna so as to transmit the sensor-generated data to the outer casing by means of an integrated slot antenna LO. 0 cc □ _ A wearable device according to claim 1 or 2, characterized in that the slot antenna is formed on the outer surface of the shell. LO o o CVJ Wearable device according to one of Claims 1 to 3, characterized in that the slot antenna is in the form of an elongated recess in the housing, wherein the recess width is limited by a first leading edge (15, 25, 35) and a second leading edge (16, 26, 36) and wherein the conductive end portions (17 and 18, 27 and 28, 37, 38) limit the length of the recess. A wearable device according to any one of the preceding claims, characterized in that the shell 5 is substantially entirely made of conductive material and that the slot antenna is arranged in the form of an elongated opening (12, 22) in the shell. A wearable device according to any one of claims 1 to 4, characterized in that the shell comprises an insulating first material portion (34) and a conductive second material (39) applied to the shell surface, the slot antenna being formed in the second material portion (39). A wearable device according to claim 6, characterized in that the conductive second material is located on the outer surface of the first material part. Wearable device according to one of the preceding claims, characterized in that the shell comprises at least two parts (24, 29), at least some of which form the longitudinal edges (25, 26) of the slot antenna. A wearable device according to claim 8, characterized in that one of said portions forms one longitudinal edge of the slit antenna and the other portions forms the opposite longitudinal edge of the slit antenna and said parts are secured together by conductive fastening members (27, 28). A wearable device according to claim 8 or 9, characterized in that one of said supported parts is a holder for holding a safety glass or plastic on the surface of the device. i c \ j o A wearable device according to any one of the preceding claims, characterized in that the x gap is filled with an insulating material such as a polymer to seal the gap. CL CO o 30 A method of forming a slot antenna in a wrist-held device (10, 20, LO 30), the method comprising taking a cover (11, 31) of a device capable of containing a radio unit in a CVJ and made at least partially of conductive material, characterized in removing conductive material from the shell to form an elongated recess comprising a first conductive edge (15, 35) and a second conductive end (16, 36) opposite the first conductive edge and two conductive end portions (17 and 18, 37 and 38) connecting the first and second edge. A method according to claim 12, characterized in that said removal of material 5 is carried out by mechanical processing such as sawing or machining or chemically such as etching. co δ c \ j i c \ j o m o X cc CL CO CO o δ o o c \ j P ATENTKRAV: