Parasitic elements of a conductive ink base for an antenna of a device

Abstract

A wearable device is provided. The wearable device includes a printed circuit board, a conductive housing, an antenna defined by a gap between the printed circuit board and the conductive housing, a cover having an outer surface, and a label. The label includes a film and a parasitic element. The parasitic element is positioned between the film and the outer surface of the cover and can be joined to the cover during an injection molding process. Further, the parasitic element can be printed on the label or otherwise disposed between a number of layers that are applied.

Description

Technical Field

[0001] The present disclosure generally relates to wearable devices. More specifically, the present disclosure relates to wearable devices including parasitic elements that improve the performance (e.g., radiation efficiency) of antennas of wearable devices.

Background Art

[0002] Modern electronic devices often include one or more radio frequency (RF) antennas to facilitate wireless communication with other electronic devices. Antennas can be included in electronic devices such as wearable devices, so that the devices can be equipped with functions of LTE, Global Positioning System (GPS), Wi-Fi®, and Bluetooth®. Frequently, especially in the case of wearable devices, antenna signals tend to radiate towards the user's skin rather than into the environment from the device, which can negatively affect the performance of the device depending on the use of the device.

[0003] Therefore, there is a need for wearable devices incorporating means to direct radiation towards the environment rather than the user's skin from the device.

Summary of the Invention

[0004] Aspects and advantages of embodiments of the present disclosure are shown in part in the following description, or can be learned from the description, or can be learned through the practice of the embodiments.

[0005] In one aspect, a wearable device is provided. The wearable device includes a printed circuit board, a conductive housing, an antenna, a cover having an outer surface, and a label including a film and a parasitic element. Further, the parasitic element is located between the film and the outer surface of the cover.

[0006] In some embodiments, the parasitic element can include a conductive ink layer. In some embodiments, the label may be insert molded on the outer surface of the cover.

[0007] In some embodiments, the label can include a decorative ink layer between the film and the parasitic element.

[0008] In some embodiments, the label can include a non-conductive masking ink layer between the decorative ink layer and the parasitic element.

[0009] In some embodiments, the label can include a first insulating ink layer. In some embodiments, the label can include a first gloss layer between the non-conductive masking ink layer and the first insulating ink layer.

[0010] In some embodiments, the label can include a second insulating ink layer, and the parasitic element can be present between the first insulating ink layer and the second insulating ink layer.

[0011] In some embodiments, the label can include an adhesive layer, and the adhesive layer can connect the label to the outer surface of the cover.

[0012] In some embodiments, the label can include a second gloss layer between the second insulating ink layer and the adhesive layer.

[0013] In some embodiments, the antenna can be a slot antenna defined by a gap between a printed circuit board and a conductive housing.

[0014] In some embodiments, the parasitic element is electrically grounded to the printed circuit board via a high-frequency grounding, a DC grounding, or a matching circuit.

[0015] In another aspect, a label for a wearable device housing an antenna is provided. The label includes a plurality of layers including a film, a decorative ink layer, a non-conductive masking ink layer, a first insulating ink layer, a parasitic element, and a second insulating ink layer. Further, the plurality of layers of the label are applied over the film, and the parasitic element includes a conductive ink layer.

[0016] In some embodiments, the label may include an adhesive layer. In some embodiments, the label may include a first gloss layer.

[0017] In some embodiments, a portion of the conductive ink layer may be exposed and may have no additional layer printed thereon.

[0018] In some embodiments, the label may be configured to be joined to a plastic cover during an insert molding process.

[0019] In yet another aspect, a method of forming a label for a wearable device housing an antenna is provided. The method includes printing one or more layers of non-conductive masking ink on a film, printing one or more layers of conductive ink on the film to define a parasitic element, printing an adhesive layer on the film to form the label, and forming the label in a shape that conforms to the shape of a cover to which it is applied.

[0020] In some embodiments, the label may be joined to the outer surface of a cover during an insert molding process, and the adhesive layer may be capable of joining the label to the cover.

[0021] In some embodiments, the method may include printing one or more layers of decorative ink on the film.

[0022] In some embodiments, the method may include printing one or more layers of insulating ink on the film.

[0023] In some embodiments, the method may include trimming the label to remove any excess portions.

[0024] These and other features, aspects, and advantages of the various embodiments of the present disclosure will become better understood with reference to the following description of the invention and the appended claims. The accompanying drawings, which are incorporated herein and form a part of this specification, illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the related principles.

[0025] A detailed description of embodiments directed to those skilled in the art is set forth in this specification with reference to the accompanying drawings.

Brief Description of the Drawings

[0026]

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DETAILED DESCRIPTION OF THE INVENTION

[0027] Reference will now be made in detail to embodiments of the present invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the present invention and not a limitation of the present invention. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the scope or spirit of the present invention. For example, features illustrated or described as part of one embodiment can be used with another embodiment to yield still another embodiment. Accordingly, the present invention is intended to cover modifications and variations that come within the scope of the appended claims and their equivalents.

[0028] As used herein, when used to modify a value, the terms "about", "approximately", or "substantially" indicate that the value can be increased or decreased by 5% and still remain within the scope of the disclosed embodiments. Further, when multiple ranges are provided, any combination of the minimum and maximum values described in the multiple ranges is contemplated by the present invention. For example, if the ranges "about 20% to about 80%" and "about 30% to about 70%" are described, the ranges "about 20% to about 70%" or "about 30% to about 80%" are also contemplated by the present invention.

[0029] Exemplary aspects of the present disclosure are directed to, for example, wearable devices that can be worn on a user's wrist or other locations on the user's body. The wearable device can include an antenna, a conductive housing (e.g., a metal housing), a circuit board (e.g., a printed circuit board) located inside the conductive housing, a cover (e.g., a plastic cover), and a label including a film and parasitic elements. Further, although any type of antenna is contemplated by the present disclosure, in some embodiments, it should be understood that the antenna can be a slot antenna defined by a gap (e.g., a gap from about 0.1 mm to about 5 mm) between the conductive housing and the printed circuit board. The slot antenna can have signals operating in a plurality of different frequency bands. For example, the slot antenna can operate in the frequency bands of one or more global navigation satellite systems (GNSS) (e.g., Global Positioning System (GPS), GLONASS, Galileo, etc.). For example, the frequency bands of one or more global navigation satellite systems can include one or more GPS frequency bands (e.g., 1164 MHz to 1189 MHz, 1563 MHz to 1587 MHz, 1215 MHz to 1240 MHz). However, since the wearable device must be compact enough to be worn on, for example, the user's wrist, the distance of the antenna from the user's wrist can be short, which can, in some situations, affect the performance (e.g., radiation efficiency) of the slot antenna in one or more GPS frequency bands. Specifically, there may be a tendency for too many signals to be directly radiated to the user's wrist through the cover, which can adversely affect the GPS performance.

[0030] It should also be understood that the antenna can operate in other frequency bands, such as the frequency bands utilized in LTE, Wi-Fi, and Bluetooth applications, as known to those skilled in the art.

[0031] Regardless of the specific application in which the antenna of the wearable device is utilized, the wearable device includes parasitic elements. The parasitic elements can be positioned or disposed between the outer surface of the cover and the film, and the film and the parasitic elements, along with other layers, form a label. The parasitic elements are disposed as close as possible to the user's wrist in order to direct RF (e.g., GPS) signals away from the wrist and into the outside air. The parasitic elements are also metallic (e.g., including conductive ink) and have a low resistance (e.g., less than about 1 ohm over the length of the parasitic element). Further, the distance between the parasitic element and the user's wrist, and the distance between the parasitic element and the ground of the system (e.g., the printed circuit board (PCB) of the device) are precisely controlled to be within a certain range because if the parasitic element is too close to the PCB, the parasitic element will not efficiently radiate at the desired frequency(ies) and will not enhance the performance of the antenna. For example, the distance D1 (see FIG. 10) between the parasitic element and the user's wrist can range from about 0.15 millimeters to about 2.5 millimeters, such as from about 0.2 millimeters to about 2.25 millimeters, such as from about 0.25 millimeters to about 2 millimeters. Thus, the parasitic element is configured and disposed to be located at a position a distance D1 from the user's wrist when the wearable device is worn by the user. On the other hand, the distance D2 (see FIG. 14) between the parasitic element and the system ground in the PCB 300 can range from about 1.25 millimeters to about 3.5 millimeters, such as from about 1.5 millimeters to about 3 millimeters, such as from about 1.75 millimeters to about 2.75 millimeters.

[0032] Furthermore, the parasitic element can be applied as one of a series of layers printed on a film surrounding the outer surface of the cover of the wearable device, thereby forming a label. Next, the film (e.g., a transparent in-mold label (IML) film), the parasitic element, and the other layers of the label are stamped and formed into the shape of the outer surface of the cover and insert molded onto the outer surface of the cover, so that the parasitic element can achieve a thin design close to the user's wrist and away from the system ground (e.g., PCB 300), and the performance of the antenna can be improved. For example, the label including the parasitic element can have a thickness T (see FIG. 11) in the range of about 0.1 millimeter to about 0.5 millimeter, for example, in the range of about 0.125 millimeter to about 0.3 millimeter, for example, in the range of about 0.15 millimeter to about 0.25 millimeter. Furthermore, the label can include a plurality of printed layers, which can include, but are not limited to, a decorative ink layer, a non-conductive masking ink layer, a first gloss layer, a first insulating ink layer, a conductive ink layer, a second insulating ink layer, a second gloss layer, and a bonding layer, and each layer described can itself include a plurality of layers. The decorative ink layer is visible from the outside of the wearable device through the transparent film, and the masking ink layer is used to hide other layers of the label, such as the conductive ink layer forming the parasitic element. The insulating ink layer(s) can add electrical stability to the parasitic element, and the gloss ink layer(s) can protect the conductive ink layer and the decorative ink layer from the high-temperature plastic during the insert molding process, in which the various layers of the label including the parasitic element are joined to the plastic bottom cover of the wearable device. Furthermore, the bonding layer bonds the label to the outer surface of the plastic cover.

[0033] Furthermore, the parasitic element can be electrically connected to the printed circuit board. For example, the parasitic element can be electrically connected to the ground plane of the printed circuit board. For example, the parasitic element can be DC grounded at a first position on the printed circuit board. Furthermore, the parasitic element can be DC grounded at a second position on the printed circuit board. The first position and the second position can be spaced apart from each other along the printed circuit board. Furthermore, the printed circuit board can include a first fastener (e.g., a spring clip, a booster pin, a compression spring, etc.) at the first position and a second fastener (e.g., a spring clip, a booster pin, a compression spring, etc.) at the second position, and couple the parasitic element to the printed circuit board through a first opening and a second opening at the first position and the second position, respectively. For example, the first contact of the parasitic element and / or the second contact of the parasitic element can be mechanically coupled and / or electrically coupled to the printed circuit board through the first fastener and the second fastener, respectively, rather than through a soldered connection.

[0034] The parasitic element can be RF grounded to the printed circuit board at a plurality of different positions. In this way, when the antenna (e.g., a slot antenna) operates in one or more frequency bands, one or more currents can be induced in the parasitic element, thereby improving the performance (e.g., radiation efficiency) of the antenna in one or more frequency bands. Furthermore, the parasitic element can improve the radiation efficiency of the antenna in one or more frequency bands by at least about 2 decibels, for example at least about 3 decibels, for example at least about 4 decibels.

[0035] The parasitic element can be electrically grounded to the printed circuit board. For example, in some embodiments, the parasitic element can be RF grounded at multiple locations on the printed circuit board. In this way, an antenna (e.g., a slot antenna) can induce one or more currents in the parasitic element when operating in one or more frequency bands, thereby improving the performance (e.g., radiation efficiency) of the antenna in one or more frequency bands. Further, the parasitic element can improve the radiation efficiency of the antenna in one or more frequency bands by at least about 2 decibels, e.g., at least about 3 decibels, e.g., at least about 4 decibels.

[0036] In some embodiments, the parasitic element can be electrically grounded to the printed circuit board via a matching circuit. It should be understood that the matching circuit can include various electronic components (e.g., capacitors, inductors, resistors, switching devices, etc.) to facilitate electrically grounding the parasitic element to the printed circuit board. In an alternative embodiment, the parasitic element can be DC grounded to the printed circuit board.

[0037] Referring now to the figures, FIG. 1 shows a wearable device 100 according to some embodiments of the present disclosure. As shown, the wearable device 100 can be worn, for example, on a user's wrist 102. For example, the wearable device 100 can include a band 104 and a housing assembly 110. The housing assembly 110 can be coupled to the band 104. In this way, the band 104 can be fastened around the user's wrist 102 to secure the housing assembly 110 to the user's wrist 102.

[0038] In some embodiments, the wearable device 100 can include a display 112 that can display content (e.g., time, date, etc.) to the user. In some embodiments, the display 112 can include an interactive display (e.g., a touch screen or touch-free). In such embodiments, the user can interact with the wearable device 100 via the display 112 to control the operation of the wearable device 100. Alternatively or additionally, the wearable device 100 can include one or more input devices 114 that can be operated by the user to interact with the wearable device 100. For example, the one or more input devices 114 can include mechanical buttons that can be operated (e.g., pressed) to interact with the wearable device 100. In some embodiments, the one or more input devices 114 can be operated to control the operation of a backlight (not shown) associated with the display 112. It should be understood that the one or more input devices 114 can be configured to enable the user to interact with the wearable device 100 in any suitable manner. For example, in some embodiments, the one or more input devices 114 can be operated by the user to navigate through one or more menus of the display 112.

[0039] In some embodiments, the wearable device 100 can be designed to be worn by the user (e.g., continuously). The wearable device 100 can collect data regarding activities performed by the user while worn, or data regarding the physiological state of the user. Such data can include data representing the ambient environment around the user or the interaction between the user and the environment. For example, the data can include motion data regarding the user's movement, ambient light, ambient noise, air quality, etc., and / or physiological data obtained by measuring various physiological characteristics of the user such as heart rate, level of sweating, body temperature, etc.

[0040] Referring now to FIG. 2, a side view of the housing assembly 110 of the wearable device 100 according to some embodiments of the present disclosure is provided. As shown, the housing assembly 110 can include a conductive housing 120. The conductive housing 120 can be attached to a band 104 that is used to secure the housing assembly 110 to the user's wrist 102 (FIG. 1). The housing assembly 110 can include a bottom cover 122 coupled to the conductive housing 120. In some embodiments, the bottom cover 122 can be coupled to the bottom of the conductive housing 120. In this way, the bottom cover 122 can contact (e.g., touch) the user's wrist 102 (FIG. 1) when the housing assembly 110 is secured to the user's wrist 102 via the band 104.

[0041] The conductive housing 120 can include any suitable conductive material. For example, in some embodiments, the conductive housing 120 can include a metal housing. The bottom cover 122 can include an insulating material. For example, in some embodiments, the bottom cover 122 can include a plastic cover.

[0042] In some embodiments, the wearable device 100 can include an electrocardiogram (ECG) electrode 200. As shown in the figure, the ECG electrode 200 can be disposed inside an opening (e.g., notch) defined by the bottom cover 122. In this way, the ECG electrode 200 can be disposed adjacent to the user's wrist 102 (FIG. 1) when the housing assembly 110 is fixed to the user's wrist 102 via the band 104. When the ECG electrode 200 is sufficiently close to the user's wrist 102, the ECG electrode 200 can be electrically connected to the user's wrist 102. Further, it should be understood that when the wearable device 100 is electrically connected to the user's wrist 102 via the ECG electrode 200, the wearable device 100 can determine one or more health measurement criteria (e.g., heart rate) of the user based at least in part on the data obtained via the ECG electrode 200.

[0043] Referring now to FIGS. 3 and 4, side views of the wearable device 100 are provided in accordance with some embodiments. FIG. 3 shows a side view of the wearable device 100 with the bottom cover 122 (FIG. 2) removed. FIG. 4 shows a side view of the wearable device 100 with the housing assembly 110 (FIG. 2) removed. As shown, the display 112 can include a display trace (e.g., ITO coating) 116 and a touch trace (e.g., ITO coating) 118 in some embodiments. The wearable device 100 can also include one or more electrodes 124 for collecting and storing data regarding any number of parameters (such as skin electrical activity) that can be communicated to the user.

[0044] The wearable device 100 can include a printed circuit board 300 disposed inside a housing assembly 110 (see FIG. 2). For example, in some embodiments, a first portion of the printed circuit board 300 can be disposed inside the conductive housing 120, and a second portion of the printed circuit board 300 can be disposed inside the bottom cover 122 (see FIG. 2). The printed circuit board 300 can include a plurality of electronic components (not shown) disposed thereon. In some embodiments, the printed circuit board 300 can include a shield can 302 that covers at least a portion of the printed circuit board 300. In this way, the shield can 302 can cover one or more of the plurality of electronic components disposed on the printed circuit board 300. Alternatively or additionally, the printed circuit board 300 can include one or more charging pins 304. In this way, the wearable device 100 can be coupled to a charging circuit (not shown) via the one or more charging pins 304 to facilitate charging of an energy storage device (e.g., a battery) of the wearable device 100.

[0045] In some embodiments, the conductive housing 120 can define an opening (e.g., a notch) for one or more electrodes 124. In this way, the one or more electrodes 124 can be visible to the user. In some embodiments, the one or more electrodes 124 can include electro-dermal activity (EDA) electrodes. In such embodiments, the user can contact (e.g., touch) the one or more electrodes 124 to facilitate measurement of one or more health metrics of the user (e.g., heart rate, blood pressure, EDA, etc.). It should be understood that the one or more electrodes 124 can be electrically coupled to the printed circuit board 300.

[0046] Referring now to FIG. 5, the printed circuit board 300 can be arranged relative to the conductive housing 120 such that a gap 400 is defined between the conductive housing 120 and the printed circuit board 300. The gap 400 can extend along a part or the entire periphery of the printed circuit board 300. In other words, at least a part of the printed circuit board 300 cannot contact (e.g., touch) the conductive housing 120.

[0047] In some embodiments, the width 402 of the gap 400 defined between the conductive housing 120 and the printed circuit board 300 can range from about 0.5 millimeter to about 10 millimeters, such as from about 1 millimeter to about 7.5 millimeters, such as from about 1.5 millimeters to about 5 millimeters. In some embodiments, the width 402 of the gap 400 can vary around the outer periphery of the printed circuit board 300. For example, the width 402 of the gap 400 between the conductive housing 120 and the printed circuit board 300 at a first portion of the outer periphery of the printed circuit board 300 can be different (e.g., wider, narrower) from the width 402 of the gap 400 between the conductive housing 120 and the printed circuit board 300 at a second portion of the outer periphery of the printed circuit board 300. In some embodiments, the printed circuit board 300 can contact the conductive housing 120.

[0048] Referring now to FIGS. 6 and 7, in some embodiments, the outer periphery of the printed circuit board 300 may include a copper-free or ground keep-out region 306. It should be understood that the ground keep-out region 306 may include an area of the printed circuit board 300 where electronic components (e.g., resistors, capacitors, etc.) cannot be placed. In some embodiments, the width 308 of the ground keep-out region 306 of the printed circuit board 300 may range from 0.1 millimeter to about 2 millimeters, such as from about 0.2 millimeter to about 1.9 millimeters, such as from about 0.3 millimeter to about 1.8 millimeters. As discussed below, the ground keep-out region 306 can function as an electrical gap. In some embodiments, the ground keep-out region 306 is around the entire periphery of the printed circuit board 300. In some embodiments, the ground keep-out region 306 is only in a part of the periphery of the printed circuit board 300.

[0049] In some embodiments, an antenna, such as slot antenna 500 (shown in dashed lines), can be defined by a gap 400 between the conductive housing 120 and the printed circuit board 300. Further, in some embodiments, the antenna 500 can be further defined by an electrical gap extending across the width 308 of the ground keep-out region 306 of the printed circuit board 300. In such embodiments, the width of the slot antenna 500 can extend across the width 402 of the gap 400 (FIG. 5) and the width 308 of the ground keep-out region 306 of the printed circuit board 300. For example, in some embodiments, the width of the slot antenna 500 can be in the range of about 0.5 millimeter to about 10 millimeters, such as from about 0.75 millimeter to about 9 millimeters, such as from about 1 millimeter to about 8 millimeters.

[0050] The slot antenna 500 may be operable in a plurality of different frequency bands. For example, the slot antenna 500 may be operable in one or more Global Navigation Satellite System (GNSS) frequency bands. In some embodiments, one or more GNSS frequency bands may include one or more GPS frequency bands. One or more GPS frequency bands may include at least one of a first GPS frequency band in the range of about 1164 megahertz (MHz) to about 1189 MHz, a second GPS frequency band in the range of about 1563 MHz to about 1587 MHz, and a third GPS frequency band in the range of about 1215 MHz to about 1240 MHz. Further, in addition to one or more GPS frequency bands, the antenna 500 can be configured to radiate in one or more frequency bands associated with cellular communication (e.g., 4G, 5G) or wireless local area communication (e.g., Wi-Fi, personal area network (e.g., Bluetooth)). However, it should be understood that the slot antenna 500 may be operable in a frequency band associated with any suitable communication standard.

[0051] In some embodiments, the slot antenna 500 can include a first grounding contact 502 and a second grounding contact 504. The first grounding contact 502 can couple the conductive housing 120 to the ground of the printed circuit board 300 at a first location. Conversely, the second grounding contact 504 can couple the conductive housing 120 to the ground of the printed circuit board 300 at a second location. In some embodiments, the first location and the second location can correspond to opposing sides of the printed circuit board 300. However, it should be understood that the first grounding contact 502 and the second grounding contact 504 can be coupled to the ground of the printed circuit board 300 at any suitable location to adjust the length of the slot antenna 500. For example, the first grounding contact 502 and the second grounding contact 504 can be arranged to shorten the slot antenna 500. Alternatively, the first grounding contact 502 and the second grounding contact 504 can be arranged to lengthen the slot antenna 500.

[0052] Referring now to FIGS. 8 and 9, parasitic elements 600 of a wearable device (e.g., the wearable device 100 of FIG. 1) are provided in accordance with some embodiments of the present disclosure. The parasitic elements 600 can be configured to increase the radiation of RF signals when the wearable device 100 is on a user's wrist. In some embodiments, the parasitic elements 600 can be disposed entirely within the housing assembly 110 of the wearable device 100 (FIG. 1). In alternative embodiments, the parasitic elements 600 can be positioned partially within the housing assembly 110. For example, a first portion of the parasitic element 600 can be disposed within the housing assembly 110, while a second portion of the parasitic element 600 can be disposed outside the housing assembly 110.

[0053] The parasitic element 600 can be electrically connected to the printed circuit board 300. For example, the parasitic element 600 can be electrically connected to the ground plane of the printed circuit board 300. In some embodiments, the parasitic element 600 can be DC grounded to the printed circuit board 300 at multiple positions. For example, the parasitic element 600 can be DC grounded to the printed circuit board 300 at the first position 602 and the second position 604 of the printed circuit board 300. As shown in the figure, the first position 602 and the second position 604 can be spaced apart from each other along the printed circuit board 300. It should be understood that in some embodiments, the parasitic element 600 can be DC grounded to the printed circuit board 300 at more than two positions (e.g., the first position 602, the second position 604).

[0054] In some embodiments, the parasitic element 600 can be coupled to the printed circuit board 300 via one or more matching circuits. For example, in some embodiments, the parasitic element 600 can be RF grounded to the printed circuit board 300 at the first position 602 via the first RF bypass capacitor 610. Further, the parasitic element 600 can be RF grounded to the printed circuit board 300 at the second position 604 via the second RF bypass capacitor 612. It should be understood that the RF bypass capacitors (e.g., the first RF bypass capacitor 610 and the second RF bypass capacitor 612) can keep the parasitic element 600 electrically insulated from the electrical ground at DC and low frequencies (e.g., non-RF frequencies). In some embodiments, the parasitic element 600 can be coupled to the printed circuit board at the first position 602 via a first matching circuit that can consist of one or more inductors and capacitors. Further, the parasitic element 600 can be coupled to the printed circuit board 300 at the second position 604 via a second matching circuit that can consist of one or more inductors and capacitors.

[0055] The parasitic element 600 can improve the performance (e.g., radiation efficiency) of the slot antenna 500 in one or more frequency bands. For example, since the parasitic element 600 is electrically coupled (e.g., RF grounded, DC grounded) to the printed circuit board 300 at multiple locations (e.g., the first location 602, the second location 604), the slot antenna 500 can induce one or more currents in the parasitic element 600 when the slot antenna 500 is operating in one or more frequency bands. It should be understood that the slot antenna 500 that induces one or more currents in the parasitic element 600 can improve the performance (e.g., radiation efficiency) of the slot antenna 500 in one or more frequency bands. For example, in some embodiments, the radiation efficiency of the antenna 500 can increase by at least 2 decibels, such as at least about 3 decibels, such as at least about 4 decibels, at least in part because the parasitic element 600 is electrically coupled to multiple locations (e.g., the first location 602, the second location 604) of the printed circuit board 300.

[0056] In some embodiments, the printed circuit board 300 can include a first fastener (e.g., a spring clip) at its first location 602 and a second fastener at its second location. In this way, the parasitic element 600 can be mechanically coupled to the printed circuit board 300 at the first location 602 and the second location 604 via the first fastener and the second fastener, respectively, as described in more detail below.

[0057] Referring now to FIG. 10, a cross-sectional view of a wearable device 100 according to some embodiments of the present disclosure is shown. The wearable device 100 includes a parasitic element 600 in accordance with some embodiments of the present disclosure, which forms one layer of the label 150 and is disposed between the film 128 and the bottom cover 122 of the housing assembly 110. Specifically, the parasitic element 600 can be disposed between the outer surface 123 of the bottom cover 122, which can be formed from a plastic material, and the film 128. Further, the bottom cover 122 is coupled to the conductive housing 120, which can be attached to a band 104 used to secure the housing assembly 110 to the user's wrist 102. The parasitic element is disposed at a distance D1 from the user's wrist 102. The distance D1 between the parasitic element 600 and the user's wrist 102 can range from about 0.15 millimeters to about 2.5 millimeters, such as from about 0.2 millimeters to about 2.25 millimeters, such as from about 0.25 millimeters to about 2 millimeters, so as to improve the radiation efficiency of the slot antenna 500 of the wearable device 100.

[0058] Referring now to FIG. 11, an enlarged cross-sectional view of the bottom cover 122 and the label 150 of FIG. 10 is shown, including the film 128, the parasitic element 600, and additional layers. The label (e.g., an in-mold label (IML)) 150 can be insert molded onto the outer surface 123 of the bottom cover 122 as shown after various additional layers and the parasitic element 600 are printed or otherwise applied to the film 128. The overall thickness T of the label 150, including the film 128, the parasitic element 600, and the additional layers, can range from about 0.1 millimeters to about 0.5 millimeters, such as from about 0.125 millimeters to about 0.3 millimeters, such as from about 0.15 millimeters to about 0.25 millimeters.

[0059] Next, to describe each layer of the label 150 in more detail, it should be understood that each of the layers described below may itself include more than one layer, such as two or more layers, such as more than three layers, such as four or more layers. In some embodiments, each layer may be composed of 2 to 10 layers, while in other embodiments, each layer may include only one individual layer. Further, the overall resistance across the length of the parasitic element 600 may be less than about 2.5 ohms, such as less than about 1.5 ohms, such as less than about 1 ohm.

[0060] To form the label 150, first, the decorative ink layer 130 can be applied to the film 128. Since the film 128 is transparent, the decorative ink layer 130 may be visible to the user or viewer from the bottom 129 of the wearable device 100. It should be understood that the decorative ink layer 130 may be printed or applied only to a part of the film 128, depending on the specific design, text, etc. that the user or other viewer of the wearable device 100 desires to see. Understanding that the decorative ink layer 130 is non-conductive, any suitable ink of any desired color can be used for the decorative ink layer 130.

[0061] Next, a non-conductive masking ink layer 132 can be applied over the decorative ink layer 130. The non-conductive masking ink layer 132 can be used to mask, hide, or obscure other layers described below from a user or any other viewer of the bottom 129 of the wearable device 100, and such masking can enhance or highlight the decorative ink layer 130. Further, the non-conductive masking ink layer 132 may not be applied over the entire inner surface 131 of the film 128 and overlying intervening layers, as various apertures 125 (see FIG. 12) may be required to facilitate external charging of the wearable device 100, or apertures 126 (see FIG. 12) may need to be exposed where sensors 127 may be disposed (see FIGS. 12 - 14), as will be described in more detail below. The non-conductive masking ink layer 132 can be any suitable color as long as the non-conductive masking ink layer 132 obscures layers that can be printed or applied over it. In some embodiments, the non-conductive masking ink layer 132 is black, but it should be understood that the color of the non-conductive masking ink layer 132 is not limited to black.

[0062] Further, a first gloss layer 134 can be applied over the non-conductive masking ink layer 132. In certain embodiments, the first gloss layer 134 can include four separate gloss layers. The first gloss layer 134 can be used to protect any of the various layers of the label 150 from thermal damage when the label 150 is applied to the bottom cover 122 by insert molding. In some embodiments, the first gloss layer 134 can be completely transparent. Further, the first gloss layer 134 may not be applied over the entire inner surface 131 of the film 128 and overlying intervening layers, as various apertures 125 may be required to facilitate external charging of the wearable device 100, or apertures 126 may need to be exposed where sensors 127 may be disposed (see FIGS. 12 - 14), as will be described in more detail below.

[0063] Next, a first insulating ink layer 136 can be applied over the first gloss layer 134. The first insulating ink layer 136 (and the second insulating ink layer 140 described below) can be used to sandwich one or more parasitic elements 600, which are conductive ink layers, to protect them from interference with other layers of the label 150. The first insulating ink layer 136 can be a dielectric ink. In some embodiments, the first insulating ink layer 136 can be completely transparent. Further, the first insulating ink layer 136 can include from about 40 wt% to about 90 wt%, such as from about 45 wt% to about 85 wt%, such as from about 50 wt% to about 50 wt% glycol ether, based on the total weight of the first insulating ink layer 136. In one embodiment, the glycol ether can be diethylene glycol ethyl acetate, but it should be understood that any other suitable glycol ether known to those skilled in the art can be used. Further, the first insulating ink layer 136 may not be applied over the entire inner surface 131 of the film 128 and over any intervening layers, as various openings 125 may be required to facilitate external charging of the wearable device 100, or the opening 126 may need to be exposed where the sensor 127 can be disposed (see FIGS. 12 - 14), as will be described in more detail below.

[0064] After the first insulating ink layer 136 is applied, a conductive ink layer forming the parasitic element 600 can be applied thereon. The conductive ink layer can be a metal, function as the parasitic element 600, and promote the enhancement of the slot antenna 500 of the wearable device 100 to result in an enhanced RF signal 106. In one particular embodiment, the conductive ink layer forming the parasitic element 600 can include two separate conductive ink layers. The conductive ink layer can be a metal paste. For example, the conductive ink layer can include silver, copper, gold, aluminum, cobalt, nickel, tungsten, zinc, rhodium, iridium, ruthenium, osmium, palladium, platinum, or combinations thereof. However, it should also be understood that non-metallic materials that are conductive can also be used. For example, in some embodiments, the conductive ink layer can be in the form of a graphite paste. The metal or conductive non-metallic material can be present in the conductive ink layer in an amount in the range of about 40 wt% to about 85 wt%, such as about 45 wt% to about 80 wt%, such as about 50 wt% to about 75 wt%, based on the total weight of the conductive ink layer. The conductive ink layer can also include a polyester resin, an ethoxylin resin, amorphous silica, or combinations thereof. The polyester resin can be present in an amount in the range of about 1 wt% to about 25 wt%, such as about 2.5 wt% to about 20 wt%, such as about 5 wt% to about 15 wt%, based on the total weight of the conductive ink layer. Further, the ethoxylin resin can be present in an amount in the range of about 0.05 wt% to about 5 wt%, such as about 0.075 wt% to about 4 wt%, such as about 0.1 wt% to about 3 wt%, based on the total weight of the conductive ink layer. Further, the conductive ink layer may not be applied over the entire inner surface 131 of the film 128 and over any intervening layers, as various openings 125 are required to facilitate external charging of the wearable device 100 or openings 126 need to be exposed where the sensor 127 can be disposed (see FIGS. 12 - 14), as will be described in more detail below.

[0065] Furthermore, a second insulating ink layer 140 can be applied on top of the conductive ink layer that forms the parasitic element 600. The second insulating ink layer 140 (and the aforementioned first insulating ink layer 136) can be used to sandwich the conductive ink layer that forms the parasitic element 600 and protect it from interference with other layers of the label 150. The second insulating ink layer 140 can be a dielectric ink. In some embodiments, the second insulating ink layer 140 can be completely transparent. Further, the second insulating ink layer 140 can include from about 40 wt% to about 90 wt%, for example, from about 45 wt% to about 85 wt%, for example, from about 50 wt% to about 50 wt% glycol ether. In one embodiment, the glycol ether can be diethylene glycol ethyl acetate, but it should be understood that any other suitable glycol ether known to those skilled in the art can be used. Further, the second insulating ink layer 140 may not be applied over the entire inner surface 131 of the film 128 and on top of any intervening layers, as various openings 125 may be required to facilitate external charging of the wearable device 100, or the opening 126 may need to be exposed where the sensor 127 can be disposed (see FIGS. 12 - 14), as will be described in more detail below. Further, the second insulating ink layer 140 may not be applied over a portion of the conductive ink layer, such that the resistance of the parasitic element 600 can be measured at one or more exposed portions 624 after injection molding of the bottom cover 122 and before final assembly of the wearable device 100, and the conductive ink layer that forms the parasitic element 600 can be connected to the printed circuit board 300 at one or more exposed portions 626 (see FIG. 12).

[0066] Furthermore, a second gloss layer 142 can be applied on top of the second insulating ink layer 140. In certain embodiments, the second gloss can include two separate gloss layers. The second gloss layer 142 can be used to protect any of the various layers of the label 150 from thermal damage when the label 150 is applied to the bottom cover 122 by insert molding. In some embodiments, the second gloss layer 142 is completely transparent. Further, the second gloss layer 142 may not be applied over the entire inner surface 131 of the film 128 and over any intervening layers, as various openings 125 are required to facilitate external charging of the wearable device 100 or openings 126 need to be exposed where the sensor 127 can be disposed (see FIG. 12), as will be described in more detail below. Further, the second gloss layer 142 may not be applied over a portion of the conductive ink layer and over any intervening layers, such that the resistance of the parasitic element 600 can be measured at one or more exposed portions 624 after injection molding of the bottom cover 122 and prior to final assembly of the wearable device 100, and the conductive ink layer forming the parasitic element 600 can be connected to the printed circuit board 300 at one or more exposed portions 626 (see FIG. 12).

[0067] Next, the bonding layer 144 can be applied on top of the second gloss layer 142. The bonding layer 144 can be used to enhance the adhesion of the label 150 to the outer surface 123 of the bottom cover 122 during the insert molding process. Further, the bonding layer 144 may not be applied over the entire inner surface 131 of the film 128 and any intervening layers, as various openings 125 are required to facilitate external charging of the wearable device 100 or openings 126 need to be exposed where the sensor 127 can be disposed (see FIGS. 12 - 14), as will be described in more detail below. Further, the bonding layer 144 may not be applied over a portion of the conductive ink layer and any intervening layers, such that the resistance of the parasitic element 600 can be measured at one or more exposed portions 624 after injection molding of the plastic cover 122 and before final assembly of the wearable device 100, and the conductive ink layer forming the parasitic element 600 can be electrically connected to the printed circuit board 300 at one or more exposed portions 626 (see FIG. 12).

[0068] Turning now to FIG. 12, a top view is shown of the film 128 and the label 150 including the parasitic element 600 of FIG. 11 with the bottom cover 122 removed, according to some embodiments of the present disclosure. As shown, the conductive ink layer forming the parasitic element 600 can include one or more exposed portions 624 without the second insulating layer 140, the second gloss layer 142, and the bonding layer 144 such that the resistance of the parasitic element 600 can be measured after injection molding of the bottom cover 122 and before assembly of the wearable device 100. Further, as shown, the conductive ink layer forming the parasitic element 600 can include one or more exposed portions 626 without the second insulating layer 140, the second gloss layer 142, and the bonding layer 144 such that the parasitic element 600 can be electrically connected to the printed circuit board 300 through the opening 620 of the bottom cover 122 (see FIGS. 13 - 14).

[0069] Referring further to FIG. 12, the placement of parasitic element 600 of cover 122 is described in more detail. In particular, the configuration of parasitic element 600 is chosen to occupy a significant portion (20 - 80%) of cover 122, and as a result, may occupy the biosensor hub of wearable device 100. Although not limited to any particular shape, the shape of parasitic element 600 may be affected by other factors such as the location of sensor 127 (e.g., a heart rate monitor sensor), or the location of the injection molding gate used to form cover 122. The shape of parasitic element 600 can be selected to balance by maximizing the gap to the nearest metal component of the wearable device (e.g., PCB 300 or conductive housing 120) while achieving a larger surface area. Thus, parasitic element 600 generally does not extend to the edge of cover 122 (and thus the edge of the biosensor hub of wearable device 100) because that region is too close to conductive housing 120. The maximum dimension of parasitic element 600 is generally about 1 / 10 to about 1 / 2 of the wavelength of the lowest frequency wave boosted by parasitic element 600. Further, it should be understood that there may be multiple parasitic elements 600 printed or otherwise disposed on film 128 to form label 150. In other words, label 150 can include one or more parasitic elements 600, such as two, three, four, five, six, or more parasitic elements 600, and the number of parasitic elements 600 can correspond to the number of openings 620 in bottom cover 122 for connecting parasitic elements 600 to printed circuit board 300 via any desired fastener or contact (e.g., spring clips 614 and booster pins 616, compression spring 618, etc. shown in FIGS. 13 - 16).

[0070] Referring now to FIGS. 13 - 14, FIG. 13 shows a perspective cross - sectional view of the printed circuit board 300, the slot antenna 500, the bottom cover 122, and the label 150, including the parasitic element 600 and the film 128 of the wearable device 100, and the various other layers described above. FIG. 14 is an enlarged view of FIG. 13, showing in more detail the opening 620 of the slot antenna 500 and the bottom cover 122 for connecting the parasitic element 600 to the printed circuit board 300 according to some embodiments of the present disclosure. The distance D2 (see FIG. 14) between the parasitic element 600 and the antenna 500 can range from about 1.25 millimeters to about 3.5 millimeters, for example from about 1.5 millimeters to about 3 millimeters, for example from about 1.75 millimeters to about 2.75 millimeters, in order to optimize the GPS performance of the wearable device 100. The opening 620 of the bottom cover 122 is generally aligned with the exposed portion 626 of the conductive ink layer forming the parasitic element 600 (see FIG. 12) in order to connect the parasitic element 600 to the printed circuit board 300. The diameter d of the opening 620 can range from about 0.6 millimeters to about 1.2 millimeters, for example from about 0.7 millimeters to about 1.1 millimeters, for example from about 0.8 millimeters to about 1 millimeter. Without intending to be limited to any particular theory, the inventors have found that such a diameter range ensures both a sufficient mechanical connection between the parasitic element 600 and the printed circuit board 300 while maintaining the strength and integrity of the film 128. Further, a conductive pad 622 in the form of an adhesive, paste, foam, or other suitable medium can be applied to the parasitic element 600 such that the conductive pad 622 is aligned with the opening 620 of the bottom cover 122, and the mechanical connection between the parasitic element 600 and the printed circuit board 300 can be strengthened via fasteners in the form of spring clips 614 and booster pins 616 or compression springs 618 (see FIGS. 15 - 16) as will be described in more detail below.Also, a conductive pad 623 in the form of an adhesive, paste, foam, or other suitable medium can be applied to the printed circuit board 300 to enhance the mechanical connection between the parasitic element 600 and the printed circuit board 300 via a spring clip 614 and a booster pin 616, a compression spring 618, or a fastener in the form of any other suitable fastener, as will be described in more detail below (see FIGS. 15-16).

[0071] As described above, FIG. 15 shows one configuration for mechanically connecting the parasitic element 600 to the printed circuit board 300 via a spring clip 614 and a booster pin 616, in which conductive pads 622 and 623 are used to enhance the mechanical connection between components. The spring clip 614 and the booster pin 616 can be used when higher frequencies are required for the antenna 500 of the wearable device 100 (e.g., for GPS applications). Further, FIG. 16 shows another configuration for mechanically connecting the parasitic element 600 to the printed circuit board 300 via a compression spring 618. The inductance inherently present in the compression spring 618 may be desirable, for example, in applications where lower frequencies are required for the antenna 500 of the wearable device (e.g., for LTE applications).

[0072] FIG. 17 shows a method 700 of assembling a wearable device 100 that may include a label 150, a cover 122, a printed circuit board 300, an antenna 500 (e.g., a slot antenna), a conductive housing 120, and a display 112. For example, in step 702, one or more decorative ink layers 130, non-conductive masking ink layer 132, gloss layer 134 and / or 142, insulating ink layer 136 and / or 140, and conductive ink layer that form parasitic elements 600 may be printed or otherwise applied onto a film 128 so as to form the label 150. Next, in step 704, a bonding layer 144 may be applied to the film 128 with the various layers printed or otherwise applied thereon. Next, in step 706, the label 150 may be formed into a desired shape (e.g., a shape corresponding to the shape of the outer surface 123 of the bottom cover 122), and then any excess label 150 may be trimmed in step 708. Thereafter, in step 710, the label 150 may be molded onto the outer surface 123 of the bottom cover 122, such as by insert molding. Next, in step 712, a parasitic element 600, which is part of the label 150, can be mechanically connected to a printed circuit board 300 disposed above the bottom cover 122. Next, in step 714, the conductive housing 120 may be attached to the bottom cover 122. Further, in step 716, the antenna 500 can be formed by a gap 400 around the printed circuit board 300. Next, in step 718, the display 112 may be attached to the conductive housing 120. Finally, it should be understood that the steps of the method 700 described above can be performed in any other suitable order, as would be understood by one of ordinary skill in the art.

[0073] Although the subject matter of the present disclosure has been described in detail with respect to its various specific and exemplary embodiments, each example is provided for illustrative purposes only and is not intended to limit the present disclosure. Those of ordinary skill in the art, upon reaching the foregoing understanding, will be able to readily make changes, modifications, and equivalents to such embodiments. Accordingly, the subject disclosure does not exclude including such modifications, variations, and / or additions to the subject matter that would be readily apparent to those of ordinary skill in the art. For example, features illustrated or described as part of one embodiment may be used in another embodiment to create yet another embodiment. Accordingly, the present disclosure is intended to cover such changes, modifications, and equivalents.

Claims

1. A wearable device, a printed circuit board, a conductive housing, an antenna, a cover having an outer surface, and a label including a film and a parasitic element, the parasitic element being located between the film and the outer surface of the cover, the wearable device.

2. The wearable device according to claim 1, wherein the parasitic element includes a conductive ink layer.

3. The wearable device according to claim 1 or 2, wherein the label is insert-molded on the outer surface of the cover.

4. The wearable device according to any one of the preceding claims, wherein the label includes a decorative ink layer between the film and the parasitic element.

5. The wearable device according to claim 4, wherein the label includes a non-conductive masking ink layer between the decorative ink layer and the parasitic element.

6. The wearable device according to claim 5, wherein the label includes a first insulating ink layer.

7. The wearable device according to claim 6, wherein the label includes a first gloss layer between the non-conductive masking ink layer and the first insulating ink layer.

8. The wearable device according to claim 6 or 7, wherein the label includes a second insulating ink layer, and the parasitic element is between the first insulating ink layer and the second insulating ink layer.

9. The wearable device according to claim 8, wherein the label includes a bonding layer, and the bonding layer connects the label to the outer surface of the cover.

10. The wearable device according to claim 9, wherein the label includes a second gloss layer between the second insulating ink layer and the bonding layer.

11. The wearable device according to claim 1, wherein the antenna is a slot antenna defined by a gap between the printed circuit board and the conductive housing.

12. A label for a wearable device including an antenna, the label including a plurality of layers including a film, a decorative ink layer, a non-conductive masking ink layer, a first insulating ink layer, a parasitic element, and a second insulating ink layer, the plurality of layers of the label being applied on the film, and further the parasitic element including a conductive ink layer, the label.

13. The label according to claim 12, further including a bonding layer.

14. The label according to claim 12 or 13, further comprising a first gloss layer.

15. The label according to any one of claims 12 to 14, wherein a part of the conductive ink layer is exposed and there is no additional layer printed thereon.

16. The label according to any one of claims 12 to 15, wherein the label is configured to be joined to a plastic cover during an insert molding process.

17. The label according to any of the preceding claims, wherein the parasitic element is electrically grounded to the printed circuit board via high-frequency grounding, DC grounding, or a matching circuit.

18. A method of forming a label for a wearable device including an antenna, comprising: printing one or more layers of non-conductive masking ink on a film; printing one or more layers of conductive ink on the film to define a parasitic element; printing a bonding layer on the film to form the label; and forming the label in a shape that conforms to the shape of a cover to which it is applied.

19. The method according to claim 18, wherein the label is joined to an outer surface of the cover during an insert molding process, and the bonding layer joins the label to the cover.

20. The method according to claim 18 or 19, further comprising printing one or more layers of decorative ink on the film.

21. The method according to any one of claims 18 to 20, further comprising printing one or more layers of insulating ink on the film.

22. The method according to any one of claims 18 to 21, further comprising trimming the label to remove any excess portions.

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