FI129965B - Diving computer with coupled antenna and water contact assembly - Google Patents

Abstract

The invention concerns a wearable diving computer and/or water contact detector assembly for detecting an underwater condition of a wearable device. The wearable diving computer (50) comprises: - a housing including a conductive bezel (51) and a body (52), said bezel including a radiator element, - a radio unit (54) functionally connected to a diving computer circuitry in said housing, said radio unit having a conductive coupling (58) to said radiator element for enabling wireless communication between said diving computer and external devices, - a water contact surface extending through said body, said water contact surface being at least in part conductive; - a water contact detector circuit (55) arranged to sense an underwater condition of said wearable diving computer, and - an underwater condition sensing circuit comprising said water contact surface, said radiator element and a low-pass filter comprising at least an inductor (56) connected at one end to said conductive coupling (58) and at the other end to a ground potential (57) of said diving computer. The water contact detector circuit (55) is configured, When water establishes a current path through said underwater condition sensing circuit, to detect an electrical connection from the water contact surface to ground and to provide an indication of an underwater condition to the diving computer (50).

Description

DIVING COMPUTER WITH COUPLED ANTENNA AND WATER CONTACT

ASSEMBLY

Background 1. Technological Field

The present disclosure relates generally to electronic devices such as wireless or portable radio devices, and to methods of utilizing the same. Specifically, the present invention relates to diving computers and water contact detection assembles for such. 2. Description of Related Technology

Antennas are commonly found in most modern radio devices, such as mobile computers, portable navigation devices, mobile phones, smartphones, personal digital assistants (PDAs), or other personal communication devices (PCD). Typically, these antennas comprise a planar radiating element with a ground plane that is generally parallel to the planar radiating element. The planar radiating element and the ground plane are typically connected to one another via a short-circuit conductor in order to achieve the desired impedance matching for the antenna. The structure is configured so that it functions as a resonator at the desired operating freguency. Typically, these internal antennas are located on a printed circuit board (PCB) of the radio device inside a plastic enclosure that permits propagation of radio freguency waves to and from the antenna(s).

N More recently, it has been desirable for these radio devices to include a metal body or

O

N an external metallic surface. A metal body or an external metallic surface may be used co

O for any number of reasons including, for example, providing aesthetic benefits such as

N

N producing a pleasing look and feel for the underlying radio device. However, the use of

I

= 25 a metallic enclosure creates new challenges for radio freguency (RF) antenna 2 implementations. Typical prior art antenna solutions are often inadeguate for use with

O metallic housings and/or external metallic surfaces. This is due to the fact that the metal

N

S housing and/or external metallic surface of the radio device acts as an RF shield which degrades antenna performance, particularly when the antenna is reguired to operate in several freguency bands.

In the case of diving computers, at least part of the body is usually made of a non- conductive polymer material. In order to detect an underwater condition in such devices, a water contact needs to be provided. These usually consist of a couple of apertures in the body, through which water may enter to conductive surfaces connected to a water detection circuit in the housing, Current flowing through the water between such conductive surfaces is detected, and an underwater condition of the device may be established. The device may then be configured accordingly, e.g. be switched to a dive state. The diving computer may also collect information from other sensors, such a pressure sensor, when determining the correct course of action in an underwater situation.

Making apertures or holes in the housing of a diving computer is however something that needs to be avoided as much as possible. Every hole must be carefully designed and sealed to avoid water entering the system, also under high water pressure conditions.

Accordingly, there is a salient need for a water detection solution for use with, for example, a diving computer device that requires less or no extra apertures or holes in the body.

EP0745915 discloses a method for minimizing erroneous shift to a water depth measurement mode by judging whether shift to a water depth measurement mode is caused by normal operation or erroneous detection and for automatically getting out of the water depth measurement mode even in the case of erroneous shift to the water depth measurement mode. Instantaneous shift to a water depth measurement mode is

N prevented when the water depth judging circuit 5 judges that a water depth value Ddpt

O from the measurement arithmetic processing circuit exceeds a predetermined value and s that the water detection switch 6 detects no water contact, and a time information

N 25 display mode is automatically returned even in the case of erroneous shift to a water = depth measurement mode. Instantaneous shift to a water depth measurement mode is 3 prevented when the water detection switch is on under conditions other than diving, and 2 an original mode is automatically returned by judging the situation precisely even in the

N case of unexpected shift to a water depth measurement mode.

N

CN204116829 discloses a diving wrist watch capable of automatically starting when entering water and relates to the technical field of wrist watches. The diving wrist watch comprises a watch shell, a movement assembly arranged in the watch shell, an LCD display screen and a bottom cover arranged on the bottom part of the watch shell, wherein the LCD display screen is fixed in the watch shell and positioned above the movement assembly, the movement assembly comprises a COB assembly provided with a microprocessor MCU, the LCD display screen is electrically connected with the microprocessor MCU, the COB assembly is provided with an analog to digital converter

ADC electrically connected with the microprocessor MCU, two sides of the watch shell are respectively provided with a water entry sensor and a water pressure sensor, the water entry sensor is electrically connected with the analog to digital converter ADC, and the water pressure sensor is electrically connected with the microprocessor MCU of the COB assembly. The beneficial effects of the diving wrist watch are that a diving function can be automatically turned on after the diving wrist watch enters water and can be automatically turned off when the diving wrist watch leaves a water face; the diving wrist watch is small in power consumption and is intelligentized, service life is prolonged, and reliability of utilization is increased.

JP2009229368 discloses a radio-controlled watch 10 including a clocking part 38 keeping the time, a reception part 20 receiving radio waves including time information and acquiring the time information from the received radio wave, a time correcting part correcting the time clocked by the clocking part 38 on the basis of the time information acquired by the reception part 20, an underwater detection part 34 detecting that the radio-controlled watch 10 exists under water, and a reception control part 36

N controlling reception operation of the reception part 20 in response to a result detected

A 25 by the underwater detection part 34. In the reception control part 36, when the = underwater detection part 34 detects existence under water, reception of the radio waves - is stopped with respect to the reception part 20. a a 3 US2019058256 discloses an assembly for an antenna, wherein the assembly comprises 3 at least one circuit board of an electronic device, a conductive body arranged at a

O 30 distance from said at least one circuit board, and an element of said antenna which comprises multiple attachment points for at least one connecting member, and said at least one connecting member is coupled to only one of said multiple attachment points at a time.

Summary

The present disclosure satisfies the foregoing needs by providing a water contact detection assembly arranged to sense an underwater condition for use within a metal or plastic housing.

In a first aspect, a wearable diving computer is provided. The wearable diving computer comprises: = ahousing including a conductive bezel and a body, said bezel including a radiator element, = aradio unit functionally connected to a diving computer circuitry in said housing, said radio unit having a conductive coupling to said radiator element for enabling wireless communication between said diving computer and external devices, — a water contact surface extending through said body, said water contact surface being at least in part conductive; — a water contact detector circuit arranged to sense an underwater condition of said wearable diving computer, — an underwater condition sensing circuit comprising said water contact surface, said radiator element and a low-pass filter comprising at least an inductor connected at one end to said conductive coupling and at the other end to a ground potential of said diving computer,

N s. K. .

N wherein said water contact detector circuit is configured, when water establishes a o> current path through said underwater condition sensing circuit, to detect an electrical

O . . . e.

N connection from said water contact surface to ground and to provide an indication of an

N se cq qe. + 25 underwater condition to said diving computer. a a < The invention also concerns the aspect of water contact detector assembly for detecting

O o . L.

Q an underwater condition of a wearable device comprising:

O

S — ahousing of said wearable device, said housing having a conductive bezel and a body;

— a radio unit in said housing, said radio unit having a conductive coupling to a radiator element in said bezel for enabling wireless communication between said wearable device and external devices, — a water contact surface extending through said body, said water contact surface being 5 at least in part conductive, — a water contact detector circuit, — an underwater condition sensing circuit comprising said water contact surface, said radiator element and a low-pass filter comprising at least an inductor connected at one end to said conductive coupling and at the other end to a ground potential of said wearable device, wherein said water contact detector circuit is configured, when water establishes a current path through said underwater condition sensing circuit, to detect an electrical connection from said water contact surface to ground and to provide an indication of an underwater condition to said wearable device.

Various embodiments of the inventive wearable diving computer and/or water contact detector assembly for detecting an underwater condition of a wearable device may include one or several of the following bulleted features: e the water contact surface may be arranged through a button which is operable from the outside of said body, and the structure of said button including said water contact surface. e thebutton may be a push-button component comprising a structure with a button part and a hollow guide part, wherein the button part consists of a touch surface

N portion connected to a shaft portion being arranged to slide in said hollow guide part

S when said button part is being engaged by a user, and wherein at least said guide 3 25 part includes said water contact surface.

N e the radio unit is a near field radio unit, such as a Bluetooth or WiFi transceiver

E unit. s e theradiounitisa satellite receiver unit, such as a GPS receiver unit. 3 e the water contact detector circuit may be arranged to deactivate said radio unit

O 30 when an underwater condition is detected.

e the water contact detector circuit may be arranged to automatically switch to an operating mode of the said diving computer when an underwater condition is detected.

Further features of the present disclosure, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description.

Brief description of the drawings

The features, objectives, and advantages of the present disclosure will become more apparent from the detailed description set forth below when taken in conjunction with the drawings, wherein:

FIG. 1 isa schematic diagram detailing the antenna apparatus according to one embodiment of the disclosure;

FIG. 2A is a perspective view of the underside of one embodiment of the coupled antenna apparatus of a radio device in accordance with the principles of the present disclosure;

FIG. 2B is a perspective of the coupled antenna apparatus of FIG. 2A configured according to one embodiment of the present disclosure;

FIG. 2C is an exploded view of the coupled antenna apparatus of FIGS. 2A-2B detailing various components of the coupled antenna apparatus in accordance with the principles of the present disclosure;

N

O

N —20 FIG. 3 shows an embodiment of a coupled antenna apparatus; &

N FIG. 4 and 4a show embodiments of a coupled antenna apparatus,

I

= . . L. .

FIG. 5 shows a schematic representation of a wearable diving computer usable in at + 2 least some embodiments of the invention,

S

N

N FIG. 6 shows a push-button construction that is usable at least in some embodiments of the invention,

Fig. 7 shows a clip washer that may be used in at least some embodiments of the inventive assembly, and

Fig. 8 shows some essential parts of an inventive water contact detector assembly.

Definitions

As used herein, the terms “antenna”, and “antenna assembly” refer without limitation to any system that incorporates a single element, multiple elements, or one or more arrays of elements that receive/transmit and/or propagate one or more frequency bands of electromagnetic radiation. The radiation may be of numerous types, e.g., microwave, millimeter wave, radio frequency, digital modulated, analog, analog/digital encoded, digitally encoded millimeter wave energy, or the like. The energy may be transmitted from location to another location, using, or more repeater links, and one or more locations may be mobile, stationary, or fixed to a location on earth such as a base station.

As used herein, the terms “board” and “substrate” refer generally and without limitation to any substantially planar or curved surface or component upon which other components can be disposed. For example, a substrate may comprise a single or multi- layered printed circuit board (e.g., FR4), a semi-conductive die or wafer, or even a surface of a housing or other device component, and may be substantially rigid or alternatively at least somewhat flexible.

The terms “frequency range”, and “frequency band” refer without limitation to any

N freguency range for communicating signals. Such signals may be communicated

N pursuant to one or more standards or wireless air interfaces. &

N As used herein, the terms “portable device”, “mobile device”, “client device”, and

Ek “computing device”, include, but are not limited to, personal computers (PCs) and 3 25 minicomputers, whether desktop, laptop, or otherwise, set-top boxes, personal digital 3 assistants (PDAs), handheld computers, personal communicators, tablet computers, ä portable navigation aids, J2ME equipped devices, cellular telephones, smartphones, tablet computers, personal integrated communication or entertainment devices, portable navigation devices, or literally any other device capable of processing data.

Furthermore, as used herein, the terms “radiator,” “radiating plane,” and “radiating element” refer without limitation to an element that can function as part of a system that receives and/or transmits radio-frequency electromagnetic radiation; e.g., an antenna.

Hence, an exemplary radiator may receive electromagnetic radiation, transmit electromagnetic radiation, or both.

The terms “feed”, and “RF feed” refer without limitation to any energy conductor and coupling element(s) that can transfer energy, transform impedance, enhance performance characteristics, and conform impedance properties between an incoming/outgoing RF energy signals to that of one or more connective elements, such as for example a radiator.

As used herein, the terms “top”, “bottom”, “side”, “up”, “down”, “left”, “right”, and the like merely connote a relative position or geometry of one component to another, and in no way connote an absolute frame of reference or any required orientation. For example, a “top” portion of a component may actually reside below a “bottom” portion when the component is mounted to another device (e.g., to the underside of a PCB).

As used herein, the term “wireless” means any wireless signal, data, communication, or other interface including without limitation Wi-Fi, Bluetooth, 3G (e.g., 3GPP, 3GPP2, and UMTS), HSDPA/HSUPA, TDMA, CDMA (e.g, IS-95A, WCDMA, etc.), FHSS,

DSSS, GSM, PAN/802.15, WiMAX (802.16), 802.20, narrowband/FDMA, OFDM,

PCS/DCS, Long Term Evolution (LTE) or LTE-Advanced (LTE-A), analog cellular,

CDPD, satellite systems such as GPS and GLONASS, and millimeter wave or

N microwave systems.

N

N

3 Overview

N In one salient aspect, the present disclosure provides improved antenna apparatus and s 25 methods of use and tuning. In one exemplary embodiment, the solution of the present 3 disclosure is particularly adapted for small form-factor, metal-encased applications that 3 utilize satellite wireless links (e.g., GPS), and uses an electromagnetic (e.g., capacitive,

S in one embodiment) feeding method that includes one or more separate feed elements that are not galvanically connected to a radiating element of the antenna. In addition,

certain implementations of the antenna apparatus offer the capability to carry more than one operating band for the antenna.

Detailed Description of Exemplary Embodiments

Reference is now made to the drawings wherein like numerals refer to like parts throughout. Detailed descriptions of the various embodiments and variants of the apparatus and methods of the disclosure are now provided. While primarily discussed in the context of portable radio devices, such as wristwatches, the various apparatus and methodologies discussed herein are not so limited. In fact, many of the apparatus and methodologies described herein are useful in any number of devices, including both mobile and fixed devices that can benefit from the coupled antenna apparatus and methodologies described herein.

Furthermore, while the embodiments of the coupled antenna apparatus of FIGS. 1-2C are discussed primarily in the context of operation within the GPS wireless spectrum, the present disclosure is not so limited. In fact, the antenna apparatus of FIGS. 1-2C are useful in any number of operating bands including, without limitation, the operating bands for: GLONASS, Wi-Fi, Bluetooth, 3G (e.g., 3GPP, 3GPP2, and UMTS),

HSDPA/HSUPA, TDMA, CDMA (e.g., IS-95A, WCDMA, etc.), FESS, DSSS, GSM,

PAN/802.15, WiMAX (802.16), 802.20, narrowband/FDMA, OFDM, PCS/DCS, Long

Term Evolution (LTE) or LTE-Advanced (LTE-A), analog cellular, and CDPD.

Exemplary Antenna Apparatus

N Referring now to FIG. 1, one exemplary embodiment of a coupled antenna apparatus

N 100 is shown and described in detail. As shown in FIG. 1, the coupled antenna

S apparatus 100 includes three (3) main antenna elements, including an outer element 102

N that is disposed adjacent to a middle radiator element 104 and an inside feed element

E 25 106. The radiator element 104, feed element 106, and the outer element 102 are not in 3 galvanic connection with one another, and instead are capacitively coupled as discussed 3 below. The outer element 102 is further configured to act as the primary radiator

O element for the antenna apparatus 100. The width of the outer element and the distance of the outer element from the middle element are selected based on specific antenna design requirements, including (i) the frequency operating band of interest, and (ii) the operating bandwidth, exemplary values of which can be readily implemented by one of ordinary skill given the present disclosure.

As shown in FIG. 1, the middle radiator element of the coupled antenna apparatus is disposed adjacent the outer element, and is separated from the outer element by a gap distance 120. For example, in one implementation, a distance of 0.2-1 mm is used, but it will be appreciated that this value may vary depending on implementation and operating frequency. Moreover, the coupling strength can be adjusted by adjusting the gap distance and by adjusting the overlapping area of the outer and middle radiator elements and by the total area of both the outer and middle radiator elements. The gap 120 enables the tuning of, inter alia, the antenna resonant frequency, bandwidth, and radiation efficiency. The middle radiator element further comprises two parts 104(a) and 104(b). The first part 104 a is the main coupling element, and the second part 104 b is left floating and not otherwise connected to the antenna structure. The second part 104 b can, for example, be left in the structure if for some mechanical reason the middle element is formed as a larger part, and only a shorter portion of it is needed as a coupling element. Disposed at one end of the middle radiator element part 104(a) is a short circuit point 110 for connecting the middle radiator element 104 to ground. The short circuit point 110 is in the illustrated embodiment located at a predefined distance 122 (typically 1-5 mm in the exemplary implementations, but may vary depending on implementation and operating frequency) from the inside feed element 106. The placement of the short circuit point 110 determines in part the resonant frequency of the coupled antenna apparatus 100. Part 104(a) is connected to part 104(b), wherein part 104(b) forms the complete middle radiator (ring).

N

N FIG. 1 also illustrates an inner feed element 106 comprised of a ground point 114, as 3 25 well as a galvanically connected feed point 116. The inner feed element 106 is disposed

N at a distance 124 from the middle radiator element 104. Furthermore, the placement and = positioning of the ground point 114 with respect to the feed point 116 determines in part 3 the resonant frequency of the coupled antenna apparatus 100. It is noted that the ground 3 point of the feed element is primarily used for feed point impedance matching. In one

O 30 implementation, the feed element forms and IFA-type (Inverted F Antenna) structure of the type known in the art, and impedance adjustment of such an element is well known by ordinary antenna designers, and accordingly not described further herein. A typical distance between the feed and ground points is on the order of 1-5 mm, but this may vary depending on frequency and application.

Moreover, it will be appreciated that the ground point may be eliminated if desired, such as by placing a shunt inductor onto the feed line. The placement of the feed point 116 and ground points 110 and 114 greatly affect the right-handed circular polarization (RHCP) and left-handed circular polarization (LHCP) isolation gains, as discussed below. As a brief aside, GPS and most satellite navigation transmissions are RHCP; satellites transmit the RHCP signal since it is found to be less affected by atmospheric signal deformation and loss than for example linearly polarized signals. Thus, any receiving antenna should have the same polarization as the transmitting satellite.

Significant signal loss will occur (on the order of tens of dB) if the receiving device antenna is dominantly LHCP polarized. In addition the satellite signal will change polarization from RHCP to LHCP each time when it is reflected from an object, for example the earth's surface or a building. Signals that are reflected once near the receiving unit have almost the same amplitude but a small time delay and LHCP, as compared to directly received RHCP signals. These reflected signals are especially harmful to GPS receiver sensitivity, and thus it is preferred to use antennas in which

LHCP gain is at minimum 5 dB to 10 dB lower than the RHCP gain.

For example, in the exemplary illustration, the feed and ground line placements are chosen for the RCHP gain to dominate and the LHCP gain to be suppressed (so as to enhance sensitivity to GPS circularly polarized signals). However, if the feed and ground lines placements were reversed, the “handedness” of the antenna apparatus 100

N would be reversed, thereby creating a dominant LHCP gain, while suppressing RHCP

N gain. To this end, the present disclosure also contemplates in certain implementations 3 25 the ability to switch or reconfigure the antenna e.g., on the fly, such as via a hardware or

N software switch, or manually, so as to switch the aforementioned “handedness” as z desired for the particular use or application. It may for example be desired to operate in 3 conjunction with a LHCP source, or receive the aforementioned reflected signals.

O

S

O Accordingly, while not illustrated, the present disclosure contemplates: (i) portable or other devices having both RHCP-dominant and LHCP dominant antennas that can operate substantially independent of one another, and (ii) variants wherein the receiver can switch between the two, depending on the polarization of the signals being received.

The coupled antenna apparatus 100 of FIG. 1 thus comprises a stacked configuration comprising an outer element 102, a middle radiator element 104 disposed internal to the outer element, and an inside feed element 106. It is noted that one middle radiator element is enough to excite on the desired operating frequency. However, for multiband operation, additional middle elements and feed elements can be added. If, as one example, a 2.4 GHz ISM band is needed, then the same outer radiator can be fed by another set of middle element and feed elements. The inside feed element is further configured to be galvanically coupled with a feed point 116, and the middle radiator element is configured to be capacitively coupled to the inside feed element. The outer element 102 is configured to act as the final antenna radiator and is further configured to be capacitively coupled to the middle radiator element. In the present embodiment, the dimensions of the outer element 102, and the feed elements 104 and 106 are selected to achieve a desired performance. Specifically, if the elements (outer, middle, inner) are measured as separated from each other, none of them would be independently tuned to a value close to the desired operating frequency. When the three elements are coupled together, however, they form a single radiator package that creates resonances in the desired operating frequency (or frequencies). A relatively wide bandwidth of a single resonance is achieved due to the physical size of the antenna, and use of low dielectric mediums like plastic. One salient benefit of this structure in the exemplary context of satellite navigation applications is that there is a typical interest in covering both GPS and GLONASS navigation systems with same antenna, i.e., 1575-1610 MHz at

N minimum, which the exemplary implementation allows.

N

S 25 It will be appreciated by those skilled in the art given the present disclosure that the

N above dimensions correspond to one particular antenna/device embodiment, and are

E configured based on a specific implementation and are hence merely illustrative of the 3 broader principles of the present disclosure. The distances 120, 122 and 124 are further 3 selected to achieve desired impedance matching for the coupled antenna apparatus 100.

O 30 For example, due to multiple elements that may be adjusted, it is possible to tune the resulting antenna to a desired operating freguency even if unit size (antenna size) varies largely. For instance, the top (outer) element size can be expanded to say 100 by 60 mm, and by adjusting the couplings between the elements, the correct tuning and matching can advantageously be achieved.

Portable Radio Device Configurations

Referring now to FIGS. 2A-2C, an exemplary embodiment of a portable radio device comprising a coupled antenna apparatus configured in accordance with the principles of the present disclosure is shown and described. Various implementations of the outer element can be utilized in conjunction with the coupled antenna apparatus embodiment illustrated in FIGS. 2A-2C in order to further enable optimization of the various antenna operating characteristics. In some embodiments, one or more components of the antenna apparatus 100 of FIG. 1 are formed using a metal covered plastic body, fabricated by any suitable manufacturing method (such as, for example an exemplary laser direct structuring (“LDS”) manufacturing process, or even a printing process such as that referenced below).

Recent advances in LDS antenna manufacturing processes have enabled the construction of antennas directly onto an otherwise non-conductive surface (e.g., onto thermoplastic material that is doped with a metal additive). The doped metal additive is subsequently activated by means of a laser. LDS enables the construction of antennas onto more complex three-dimensional (3D) geometries. For example, in various typical smartphones, wristwatch and other mobile device applications, the underlying device housing and/or other antenna components on which the antenna may be disposed, is manufactured using an LDS polymer using standard injection molding processes. A

N laser is then used to activate areas of the (thermoplastic) material that are then

O subseguently plated. Typically an electrolytic copper bath followed by successive s additive layers such as nickel or gold are then added to complete the construction of the

N 25 antenna.

T

E Additionally, pad printing, conductive ink printing, FPC, sheet metal, PCB processes

S$ may be used consistent with the disclosure. It will be appreciated that various features

S of the present disclosure are advantageously not tied to any particular manufacturing

N technology, and hence can be broadly used with any number of the foregoing. While some technologies inherently have limitations on making e.g., 3D-formed radiators, and adjusting gaps between elements, the inventive antenna structure can be formed by using any sort of conductive materials and processes.

However, while the use of LDS is exemplary, other implementations may be used to manufacture the coupled antenna apparatus such as via the use of a flexible printed circuit board (PCB), sheet metal, printed radiators, etc. as noted above. However, the various design considerations above may be chosen consistent with, for example, maintaining a desired small form factor and/or other design requirements and attributes.

For example, in one variant, the printing-based methods and apparatus described in

US9780438, are used for deposition of the antenna radiator on the substrate. In one such variant, the antenna radiator includes a quarter-wave loop or wire-like structure printed onto the substrate using the printing process discussed therein.

The portable device illustrated in FIGS. 2A-5C (i.e. a wrist mountable watch, asset tracker, sports computer, diving computer, etc. with GPS functionality) is placed in an enclosure 200 configured to have a generally circular form. However, it is appreciated that while this device shown has a generally circular form factor, the present disclosure may be practiced with devices that possess other desirable form factors including, without limitation, square, rectangular, other polygonal, oval, irregular, etc. In addition, the enclosure is configured to receive a display cover (not shown) formed at least partly with a transparent material such as a transparent polymer, glass or other suitable transparent material. The enclosure is also configured to receive a coupled antenna apparatus, similar to that shown in FIG. 1. In the exemplary embodiments, the enclosure is formed from an injection molded polymer, such as polyethylene or ABS-PC. In one

N variant, the plastic material further has a metalized conductive layer (e.g., copper alloy)

N disposed on its surface. The metalized conductor layers generally form a coupled 3 25 antenna apparatus as illustrated in FIG. 1.

N z Referring now to FIGS. 2A-2C, one embodiment of a coupled antenna apparatus 200 3 for use in a portable radio device in accordance with the principles of the present 3 disclosure is shown. FIG. 2A illustrates the underside of the coupled antenna apparatus

N 200 illustrating the various connections made to a printed circuit board (219, FIGS. 2B

N 30 and 2C). Specifically, FIG. 2A illustrates short circuit point 210 for the middle ring radiator element 204 as well as the short circuit point 216 and galvanic feed point 214 for the inner feed trace element 206. Both the inner feed trace element and middle ring radiator element are disposed internal to the front cover 203 of the illustrated embodiment for the coupled antenna apparatus for use with a portable radio device. The front cover 203 (see FIGS. 2A and 2C) is manufactured, according to a first embodiment of the disclosure, using a laser direct structuring (“LDS”) polymer material that is subsequently doped and plated with an outer ring radiating element 202 (see

FIGS. 2B-2C). The use of LDS technology is exemplary in that it allows complex (e.g. curved) metallic structures to be formed directly onto the underlying polymer material.

The outer ring radiating element 402 may alternatively comprise a stamped metallic ring formed from e.g., stainless steel, aluminum or other corrosion resistant material (if exposed environmental stress without any additional protective coating). The selected material ideally should have adequate RF conductivity. Plated metals can be also used, for example nickel-gold plating, etc. or other well-known RF materials that are disposed onto the front cover 203.

In addition, a middle ring radiator element 204 is disposed on the inside of the doped front cover 203 using LDS technology as well in an exemplary embodiment. The middle ring radiator element 204 is constructed into two (2) parts 204(a) and 204(b). In an exemplary implementation, element 204(«) is used to provide a favorable place for the ground contact (short circuit point) 210 to mate. The short circuit point 210 is disposed on one end of the first part 204(a) of middle ring radiator. Coupled antenna apparatus 200 further includes an LDS polymer feed frame 218 onto which an inside feed element 206 is subsequently constructed. The inside feed element comprises a galvanic feed point 216 as well as a short circuit point 214, both of which are

N configured to be coupled to a printed circuit board 219 at points 216" and 214,

A 25 respectively (see FIG. 2C). The inside feed frame element is disposed adjacent to the = middle radiator ring element part 204 such that coaxial feed point is at a distance 222 - from the middle radiator element short circuit point 210. Short circuit points 210 of the

E middle radiator element and 214 of the inside feed element are configured to interface

S$ with the PCB 219 at points 210" and 214’, respectively. A back cover 220 is positioned

S 30 on the underside of the printed circuit board and forms the closed structure of the

S coupled antenna apparatus.

While the aforementioned embodiments generally comprise a single coupled antenna apparatus disposed within a host device enclosure, it will also be appreciated that in some embodiments, additional antenna elements in addition to, for example, the exemplary coupled antenna apparatus 100 of FIG. 1 can be disposed within the host device. These other antenna elements can designed to receive other types of wireless signals, such as and without limitation e.g., Bluetooth®, Bluetooth Low Energy (BLE), 802.11 (Wi-Fi), wireless Universal Serial Bus (USB), AM/FM radio, International,

Scientific, Medical (ISM) band (e.g., ISM-868, ISM-915, etc.), ZigBee®, etc., so as to expand the functionality of the portable device, yet maintain a spatially compact form factor.

The coupled antenna apparatus 200 as illustrated may comprise of two antenna assemblies comprising a middle radiator element and an inside feed element (not shown), both having a common outer ring element 202. The two antenna assemblies may operate in the same frequency band, or alternatively, in different frequency bands.

For example, antenna assembly “a” may be configured to operate in a Wi-Fi frequency band around 2.4 GHz, while antenna assembly may be configured to operate in the

GNSS frequency range to provide GPS functionality. The operating frequency selection is exemplary and may be changed for different applications according to the principles of the present disclosure.

Moreover, the axial ratio (AR) of the antenna apparatus of the present disclosure can be affected when antenna feed impedance is tuned in conjunction with user body tissue loading (see prior discussion of impedance tuning based on ground and feed trace

N locations). Axial ratio (AR) is an important parameter to define performance of

N circularly polarized antennas; an optimal axial ratio is one (1), which correlates to a 3 25 condition where the amplitude of a rotating signal is equal in all phases. A fully linearly

N polarized antenna would have infinite axial ratio, meaning that its signal amplitude is = reduced to zero when phase is rotated 90 degrees. If an optimal circular polarized signal 3 is received with a fully linearly polarized antenna, 3 dB signal loss occurs due to 3 polarization mismatch. In other words, 50% of the incident signal is lost. In practice, it

O 30 is very difficult to achieve optimal circular polarization (AR=1) due to asymmetries on mechanical constructions, etc. Conventionally used ceramic GPS patch antennas typically have an axial ratio of 1 to 3 dB when used in actual implementations. This is considered to be “industry standard”, and has a sufficient performance level.

Furthermore, it will also be appreciated that the device 200 can further comprise a display device, e.g., liquid crystal display (LCD), light emitting diodes (LED) or organic LED (OLED), TFT (thin film transistor), etc., that is used to display desired information to the user. Moreover, the host device can further comprise a touch screen input and display device (e.g., capacitive or resistive) or the type well known in the electronic arts, thereby providing user touch input capability as well as traditional display functionality.

Figure 3 shows an additional embodiment of a coupled antenna apparatus including a transient voltage suppressor (TVS). Figure 3 is similar to figure 1 described above. In certain situations it is desirable to have the outer radiator element 132 as a portion of the antenna. The outer radiator element 132 can share some or all of the properties as the outer element 102 as discussed above. However, as the outer radiator element 132 is a portion of the antenna it cannot readily be grounded in the antenna configuration of figure 1. Therefore, a TVS diode 130 is electrically connected to the outer radiator element 132. An example schematic thereof is shown in Figure 3. The TVS 130 therefore connects the outer radiator element 132 to a ground when there is a big enough potential or voltage in the outer radiator element 132. As such, the TVS diode protects the electronics within a device from being harmed from, for example, an electric spark outside of the device.

N In the example of Figure 3, the first part 104(a) of the middle radiator element, and the

O inner feed element 106 are connected to the ground. Additionally, they are inside the s electrostatic discharge (ESD) protection provided by the outer radiator element 132

N 25 connected to the TVS diode. Without TVS grounding a large enough potential will in = practice find its way through the outermost conductive portion of a device and damage 3 internal electronics. One particular problem in smart watches and mobile devices is that 3 large potentials will pass through display lines and connections in and damage display ä drivers.

Figure 4 shows an embodiment of an inventive coupled antenna apparatus including a transient voltage suppressor circuit 134. Figure 4 is similar to figure 1 and 3 described above. In certain situations it is desirable to have the outer radiator element 132 as a portion of the antenna. The outer radiator element 132 can share some or all of the properties as the outer element 102 as discussed above. However, as the outer radiator element 132 is a portion of the antenna it cannot readily be grounded in the antenna configuration of figure 1. Therefore, an LC circuit 134 is electrically connected to the outer radiator element 132. An example thereof is shown in Figure 4. The LC circuit 134 is closed, i.e. connects the outer radiator element 132 to ground at low frequencies and DC Direct Current). The value of the impedance of the LC the circuit is thus selected to allow electrostatic discharges to flow through it. The LC circuit 134 protects the electronics within a device from being harmed from, for example, an electric spark outside of the device.

At its resonant frequency, the LC 134 circuit makes a stopband and acts like an open circuit. The values of the L and C components are chosen for the circuit to resonate at the antenna’s working frequency.

In the example of Figure 4, the first part 104(a) of the middle radiator element, and the inner feed element 106 are connected to the ground. Additionally electrostatic discharge (ESD) protection is provided by the outer radiator element 132 connected to the LC circuit 134. Without such a high-impedance grounding a large enough potential will in practice find its way through the outermost conductive portion of a device and damage internal electronics. One particular problem in smart watches and mobile devices is that

N large potentials will pass through display lines and connections in and damage display

N drivers. 3

N 25 According to certain examples, a fixed or variable capacitor C, or one or more = switchable capacitors C1, C2 (see Fig. 4A) may be added in parallel to the coil L, in 3 order to make the LC circuit 134 tunable. By tuning a variable capacitor C, and/or by 3 switching capacitors C1 and C2 with suitably selected capacitances on and/or off, the

N LC circuit 134 or 134a can be tuned to different freguencies received by the antenna, s 30 such as to the freguencies of GPS, Glonass and Galileo navigation systems. Also other wireless systems may be interfaced with the inventive device, such as Bluetooth or

WiFi, which frequencies may be received and the LC circuit 134 or 134a tuned to resonate on such frequencies as well, thus providing optimization of the antenna performance in a variety of systems. Surprisingly, LC circuits 134 or 134a provides

ESD protection with a very small negative impact on antenna performance.

A bezel, for example for a wrist-wearable electronic device, can have an inner and an outer surface. All or a portion of the outer surface of the bezel can be an outer radiator element. Furthermore, one or more additional radiator elements can be located, housed and/or supported by the inner surface of the bezel. According to certain examples, one or more of the additional radiator elements are electrically isolated from, but mechanically connected to the inner surface of the bezel.

As described above, a coupled antenna apparatus can comprise a bezel which includes an outer radiator element. The outer radiator element forms a part of the antenna structure. The outer radiator element can be, for example, a section and/or sector of the bezel. The outer radiator element can have a closed loop structure and can even be the entire bezel. In examples where the bezel is metallic, the outer radiator element can be an integral portion of the bezel. The outer radiator element can also be a separate portion of the bezel which is combined with one or more other portions to form a bezel.

Numerous types of electronic devices can include a coupled antenna apparatus as described herein. One example is a wrist-wearable electronic device having an outer housing which includes one or more portions. At least one of the portions of the housing can be a bezel. According to certain examples the outer housing of the device includes a

N bezel, in accordance with any bezel discussed above, and a body. The body and/or the

O bezel can contain a plurality of electrical components. An outer portion of the bezel can s contain a metallic portion which is, or acts as an outer radiator element. The outer

N 25 radiator element can be generally ungrounded. However, said outer radiator element can = be electrically coupled, for example by a pogo pin, to a TVS device housed within the 3 outer housing, to protect at least some of the plurality of internal electrical components 3 from large potentials which the outer radiator element may be thereby exposed to.

O

O

N Furthermore, according to certain examples, an electronic device may further include at least one screw. The screw may be primarily for mechanically coupling the bezel to the body of the outer housing, and/or to one or more other portions of the device. The screw may be electrically conductive, e.g. metallic, and therefore in electrical contact with a portion of the bezel and/or outer radiator element. Thus, the screw can form an additional conductive portion of the outer radiator element. In certain embodiments the screw may electrically ground at least a portion of the bezel. Furthermore, other connection means besides a screw but having similar electro-mechanical properties may be used in place of an actual screw.

Referring now to Figure 5, a schematic representation of a diving computer 50 that is usable in connection with at least some embodiments of the invention is shown. The wearable diving computer has a housing which consists mainly of a conductive bezel 51 and a body 52. The bezel includes a radiator element, such an ungrounded outer radiator element 202 shown in Figures 2A — 2C. A radio unit 54 is functionally connected to the diving computer circuitry (not shown) enclosed in the housing, and has a conductive coupling 58 to the radiator element, for enabling wireless communication between the diving computer and external devices. A suitable core circuit for the radio unit may be a

Bluetooth processor (BLE SoC) nRF51422 by Nordic Semiconductor®, for example.

The radio unit 54 may also comprise a balun transformer like NRF02D3 by ST

Microelectronics® between the Bluetooth processor and the inductance 56, for example, to convert between balanced and unbalanced signals and/or to transform impedances between the processor and inductance circuits. The inductance 56 may be a coil such as

LQGI15HS22NJ02D by Murata®, with which the antenna is grounded for DC currents and a current path 59 for the water contact is established.

N Also included is a water contact detector circuit 55 which is arranged to sense when the

N wearable diving computer enters an underwater condition. An exemplary push button 3 25 53 extending through the body 52 is operable from the outside of the body. The push-

N button includes a conductive water contact surface, enabling the push- button to convey z a water contact signal to the water contact detector circuit 55, sensed as a voltage drop 3 over the resistor R. The push-button 53 may be a push-button or navigation button that 3 is part of the user interface of the diving computer, and using it in that capacity has no

S30 effect on the water contact detection or vice versa.

Instead of a push-button, the water contact may be arranged in a navigation-type of button, or by any surface or structure in the housing being in contact with water when the diving computer is submerged.

As an alternative to sensing a voltage drop over the resistor R may be current sensing in the water contact detector circuit using a current supply. This may render the resistor R obsolete and the detection may be made by a semiconductor circuit. Further embodiments may include various signal forms, like DC, pulsed DC, or AC (alternating current).

The underwater condition sensing circuit in Fig. 5 comprises the conductive coupling 58 between the radiator element in the bezel 51 and the radio unit 54 and a low-pass filter, which comprises at least the inductor 56, connected at one end to the conductive coupling 58 and at the other end to the ground potential 57 of the diving computer.

Thus the underwater condition sensing circuit 58, 56 and 57 senses when water establishes a conductive path 59 between from water contact surface of the push-button to the bezel 51 and the radiator element onwards as a DC short-circuit through the inductance 56 to ground, thus providing in the sensing loop of the resistor R a voltage indication of an underwater condition to the water contact detector circuit 55.

Importantly, the radio unit 54 will not see this short-circuit of its radiator element, because of the low-pass filter 56. Typically the radio unit operates in the 2.4 GHz range for Bluetooth applications and in the 1.5 GHz range for GPS applications, for example.

A DC short-circuit will pass the filter 56, but will not pass GHz range signals.

N According to some embodiments, the water contact detector circuit 55 may be arranged

N to automatically switch to a dive operating mode of the diving computer when an 3 underwater condition is detected. In some embodiments, the contact detector circuit 55

N 25 may be arranged to deactivate the radio unit when an underwater condition is detected,

E for example in order to reduce power consumption.

S$ Referring now to Figure 6, a push-button component that is usable at least in some

S embodiments of the invention is shown. The push-button component interfaces with the device housing at an aperture in the housing, and has a button part 60 having a touch surface portion 64a with a circular or otherwise suitably shaped form to be engaged by a touch or press from a user’s finger. The button part 60 also includes a shaft portion 64b connected to the touch surface portion 64a and which preferably is integral with and perpendicular to the shaft portion 64b, as shown. The shaft portion 64b is sliding in the fixed guide portion 63 inwards and outwards, as shown by arrow B, when the button part 60 is engaged by a user.

The fixed guide portion 63 acts as a bushing for the button part 60. The shaft portion 64b of the push-button is supported inside the guide part by greased O-rings 69a. A spring 69b with a washer 69c provides the necessary return force and resistance to the touch surface 64a.

At the other end of the guide portion 63, there is a further bushing surface 69d for the touch surface portion 64a of the button part.

The outward movement of the push-button 64a, 64b is limited by a stopper 67, which abuts against an end portion of the guide part 63.

Preferably, the fixed guide part 63 includes a conductive water contact surface area A, where water will enter in an underwater condition, which may then be sensed via a conducting element 65 and a detector circuit 66, as described above. Obviously, the water contact may be made from any conductive surface in the push-button component.

However, because the button 64a, 64b may be made from non-conductive material, allowing more freedom of design and the device aesthetics can be improved, and because a more reliable connection to a sensor circuit can be made from a fixed structure, the water contact surface area A on the guide part 63 is a preferred solution.

In some embodiments, there may be grooves 61a and 62a (dashed line) at the body part

N 61 and the bottom part 62 of the device, respectively. The purpose of the grooves are to

S flush in water to the water contact surface area A of the guide part 63, and to prevent the 3 25 buildup of pressure and/or air bubbles in between the push-button 60 and the housing of

N the device, that would impair the water contact to the guide part. The shaft portion 64b

E and the button portion 64a may be coated, for example to inhibit creep currents from x causing false water electrical contact indications.

D

S Water is blocked from entering the interior of the device by a seal, such as an O-ring 68,

N 30 running between the guide part 63, a body part 61 and a bottom part 62 of the device, respectively.

In Fig. 6 is also shown an inventive clip washer 65 that is pressed or snapped onto the guide part 63, and a connector element that extends from the clip washer 65 and provides electrical connection stud 66. The clip washer will be described in detail in the following, referring to now Figs. 7 and 8.

In Fig. 7, a clip washer that may be used in some embodiments of the inventive assembly is shown. The clip washer 70 is preferably made of an integral piece of sheet metal, having a general appearance of a circlip fastener consisting of a semi-flexible metal clip ring 71 with an open end which can be pressed or snapped onto the guide portion 63 in Fig. 6.

The clip washer is provided with a flexible connector element 73 extending a distance from the washer to provide an electrical connection, such as contact stud 74, for a circuit in the device. Such a circuit may be a water contact detection circuit, as shown in

Fig. 5. The element 73 may be integral with the clip 70 and made of the same piece of sheet metal, or it may be a tongue, a spring, a wire, or any other suitable connector element.

In some embodiments the inner edges 72 of the clip ring 71 may be sharp and cut in to a conductive surface of the guide portion, thus locking itself into place when pressed onto the guide portion. In some further embodiments, the inner edges 72 of the clip ring 71 may be rounded and to snap into a circumferential groove on the conductive surface of the guide portion, thus locking itself into place when pressed onto a portion.

As the flexible connector element 73 at the contact stud 74 is subject to a force 77 from a counterpart stud on a printed circuit board or the like, it is in some embodiments

N preferable to ensure that the clip washer 70 does not start to rotate around the guide

O portion. This may be prevented by providing support from the device housing or 3 25 structure at some point 75a, 75b, 75c of the clip washer. In Fig. 7 is shown such a

N support 76 structure at point 75a, which prevents a downward force 77 from rotating the

E washer 70.

S Fig. 8 shows some essential parts of an inventive assembly. A clip washer 81 as shown 3 in Fig. 7 is mounted, by pressing and/or snapping, onto a guide portion 82 of an

S 30 assembly, similar to the guide portion 63 of Fig. 6. The guide portion supports a button part 80, consisting of a touch surface portion 83 and a shaft portion 84 in the guide portion, as shown by dashed lines. The shaft portion 84 slides in the guide portion inwards and outwards, as shown by arrow 85, when the button part 80 is engaged by a user.

It is to be understood that the embodiments of the invention disclosed are not limited to the particular structures, process steps, or materials disclosed herein, but are extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that terminology employed herein is used for the purpose of describing particular embodiments only and is not intended to be limiting.

Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment.

As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unigue member. Thus, no individual member of such list should be construed as a de facto eguivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary. In addition, various embodiments and example of the present invention may be referred to herein

N along with alternatives for the various components thereof. It is understood that such

O embodiments, examples, and alternatives are not to be construed as de facto eguivalents s of one another, but are to be considered as separate and autonomous representations of

N 25 the present invention.

T

E Furthermore, the described features, structures, or characteristics may be combined in

S$ any suitable manner in one or more embodiments. In the following description,

S numerous specific details are provided, such as examples of lengths, widths, shapes,

N etc., to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention.

While the forgoing examples are illustrative of the principles of the present invention in one or more particular applications, it will be apparent to those of ordinary skill in the art that numerous modifications in form, usage and details of implementation can be made without the exercise of inventive faculty, and without departing from the principles and concepts of the invention. Accordingly, it is not intended that the invention be limited, except as by the claims set forth below.

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Claims (12)

1. A wearable diving computer (50), characterized in that the wearable diving computer comprises: — a housing including a conductive bezel (51) and a body (52), said bezel (51) including a radiator element (202), — a radio unit (54) functionally connected to a diving computer circuitry in said housing, said radio unit (54) having a conductive coupling (58) to said radiator element (202) for enabling wireless communication between said diving computer (50) and external devices, — a water contact surface extending through said body (52), said water contact surface being at least in part conductive; — a water contact detector circuit (55) arranged to sense an underwater condition of said wearable diving computer (50), — an underwater condition sensing circuit (58, 56, 57) comprising said water contact surface, said radiator element (202) and a low-pass filter (56) comprising at least an inductor connected at one end to said conductive coupling and at the other end to a ground potential (57) of said diving computer (50), wherein said water contact detector circuit is configured, when water establishes a current path (59) through said underwater condition sensing circuit, to detect an electrical connection from said water contact surface to ground and to provide an indication of an underwater condition to said diving computer (50).

2. A wearable diving computer (50) according to claim 1, wherein said water contact N surface is arranged through a button (53) which is operable from the outside of said N body (52), and the structure of said button (53) including said water contact surface. co = 25

3. A wearable diving computer (50) according to claim 2, wherein said button (53) is a - push-button component comprising a structure with a button part (60) and a hollow S guide part (63), wherein the button part consists of a touch surface portion (64a) 3 connected to a shaft portion (64b) being arranged to slide in said hollow guide part (63) S when said button part (60) is being engaged by a user, and wherein at least said guide & 30 part (63) includes said water contact surface.

4. A wearable diving computer (50) according to any of claims 1 - 3, wherein said radio unit (54) is a near field radio unit, such as a Bluetooth or WiFi transceiver unit.

5. A wearable diving computer (50) according to any of claims 1 - 3, wherein said radio unit (54) is a satellite receiver unit, such as a GPS receiver unit.

6. A wearable diving computer (50) according to any of claims 1 - 5, wherein said water contact detector circuit is arranged to deactivate said radio unit (54) when an underwater condition is detected.

7. A wearable diving computer (50) according to any of claims 1 - 5, wherein said water contact detector circuit is arranged to automatically switch to an underwater operating mode of the said diving computer (50) when an underwater condition is detected.

8. A water contact detector assembly for detecting an underwater condition of a wearable device (50), characterized in that the water contact detector assembly comprises: — a housing of said wearable device (50), said housing having a conductive bezel (51) and a body (52); — a radio unit (54) in said housing, said radio unit (54) having a conductive coupling (58) to a radiator element (202) in said bezel (51) for enabling wireless communication between said wearable device (50) and external devices, — a water contact surface extending through said body (52), said water contact surface being at least in part conductive, — a water contact detector circuit (55), N — an underwater condition sensing circuit (58, 56, 57) comprising said water N contact surface, said radiator element (202) and a low-pass filter (56) comprising S at least an inductor connected at one end to said conductive coupling and at the N 25 other end to a ground potential (57) of said wearable device (50), I E wherein said water contact detector circuit is configured, when water establishes a S$ current path (59) through said underwater condition sensing circuit, to detect an S electrical connection from said water contact surface to ground and to provide an N indication of an underwater condition to said wearable device (50).

9. A water contact detector assembly according to claim 8, wherein said water contact surface is arranged through a button (53) which is operable from the outside of said body (52), and the structure of said button (53) including said water contact surface.

10. A water contact detector assembly according to claim 9, wherein said button (53) is a push-button component comprising a button part (60) and a hollow guide part (63), wherein the button part (60) consists of a touch surface portion (64a) connected to a shaft portion (64b) being arranged to slide in said hollow guide part (63) when said button part (60) is being engaged by a user, and wherein at least said guide part (63) includes said water contact surface.

11. A water contact detector assembly according any of claims 8 - 10, wherein said water contact detector circuit is arranged to deactivate said radio unit (54) when an underwater condition is detected.

12. A water contact detector assembly according to any of claims 8 - 11, wherein said water contact detector circuit is arranged to automatically switch to an underwater operating mode of said wearable device (50) when an underwater condition is detected. N N O N © <Q N N I a a + O O LO O N O N