Wearable band and wearable display apparatus

Abstract

A wearable band of a size and length suitable to be positioned around a limb, or other body part, of a user, said band comprising a flexible bistable strip movable between a first state, in which it is substantially axially straight, and a second, ring-like state, and having a yield point, said band being configured such that generally radial application of pressure exceeding said yield point to an end of said hand causes it to move, under its own tension, from said first state to said second state, wherein a portion of the length of said bistable strip at a free end thereof has a progressively reducing width and/or thickness such that the tensile force in said portion, when said band is in said first configuration, gradually lessens along said portion toward said free end.

Claims

1. An electronic device comprising a power supply and a wearable band of a size and length suitable to be positioned around a limb, or other body part, of a user, said band comprising a flexible bistable strip movable between a first state, in which it is axially straight, and a second, ring-shaped state, and having a yield point, said band being configured such that a radial application of pressure exceeding said yield point to an end of said band causes it to move, under its own tension, from said first state to said second state, wherein a portion of the length of said bistable strip at a free end thereof has a progressively reducing width and/or thickness such that a tensile force in said portion, when said band is in said first state, gradually lessens along said portion toward said free end, the tensile force that gradually lessens being transformed, in use, into a progressively reducing kinetic energy along said portion, toward said free end, that results in a corresponding slowing and softening of movement of the band from said first state to said second state, said wearable band further incorporating a layer located along the length of said bistable strip, said layer having thereon an electronic display comprising one or more light emitting diodes and/or a flexible display screen.

2. The electronic device comprising the wearable band according to claim 1, wherein said portion of the length of the bistable strip has at least one side edge that is tapered toward said end, thereby progressively reducing the width of the bistable strip along the length of said portion.

3. The electronic device comprising the wearable band according to claim 2, wherein both side edges of said portion of the length of the bistable strip are tapered toward said end, thereby progressively reducing the width of the bistable strip along the length of said portion.

4. The electronic device comprising the wearable band according to claim 1, wherein the angle of taper of the or each side edge is between 5° and 20° relative to the axial length of the strip.

5. The electronic device comprising the wearable band according to claim 1, wherein said portion of the length of the strip is at least one sixth of the total length of the strip.

6. The electronic device comprising the wearable band according to claim 1, wherein said portion of the length of the strip is between 30-50% of the total length of the strip.

7. The electronic device comprising the wearable band according to claim 1, wherein the bistable strip comprises an elongate strip of flexible tempered steel, bistable reeled composite or graphene.

8. The electronic device comprising the wearable band according to claim 7, wherein said bistable strip is transversely concave.

9. The electronic device comprising the wearable band according to claim 1, configured to be worn around a user's limb or head.

10. The electronic device comprising the wearable band according to claim 1, further comprising a control unit including a power supply and a conductive strip incorporated in said wearable band connecting said power supply to one or more electronic components on a flexible band incorporated in or on said wearable band.

11. The electronic device comprising the wearable band according to claim 1, wherein the wearable band comprises a rubber backing, a strip of thin steel, bistable reeled composite or graphene forming the bistable strip, an electro-luminescent display, a filter layer and an anti-moisture coating.

Description

(1) These and other aspects of the invention will be apparent from the following specific description, in which embodiments of the invention are described, by way of examples only, and with reference to the accompanying drawings, in which:

(2) FIG. 1 is a plan view of display apparatus including a wearable band according to an exemplary embodiment of the present invention;

(3) FIG. 1a is a schematic plan view of the bistable strip of a wearable band according to an exemplary embodiment of the present invention;

(4) FIG. 2 is a perspective view of the apparatus of FIG. 1 showing the details of the construction of the apparatus;

(5) FIG. 2a is a cross-section of part of FIG. 2 to an enlarged scale; and

(6) FIG. 3 is a perspective view of the apparatus of FIG. 1 in which the wearable band is in a second, coiled or rolled configuration.

(7) Referring to FIG. 1 of the drawings, there is illustrated a display apparatus, generally referred to as 10, including a wearable band according to an exemplary embodiment of the present invention. The display apparatus 10 comprises two main elements, a control unit 12 and a sprung band 14. The control unit 12 and the sprung band 14 may or may not be permanently connected, and the present invention is not necessarily intended to be in any way limited in this regard.

(8) The sprung band 14 is constructed of several layers which are shown in greater detail in FIG. 2 of the drawings, and which may be held together by, for example, double-sided LSE clear 3M adhesive between adjacent layers.

(9) The bottom layer 16 may, for example, comprise natural rubber or similarly resiliently flexible material for comfort and durability, and may be around 500 μm thick. Above that, there is a bistable layer 18 composed of, for example, plastic coated hardened and tempered steel, which may be around 50 μm thick. The bistable layer 18, which can be additionally seen in FIG. 1a of the drawings, is configured to be moveable, under its own tension, from a first state, in which it is substantially axially straight, and a second state in which it is curved or coiled into a ring-like state (as illustrated in FIG. 3 of the drawings).

(10) It will be appreciated that the bistable layer 18 could be formed, additionally or alternatively, of an alternative material to tempered steel. For example, bistable reeled composite (BRC) or graphene could be advantageously utilised. BRC is a structural material formed of high-tech fibres embedded in thermoplastic polymers such that it can take first and second states, namely a long, rigid structure and coiled strip respectively. Such materials may be advantageous compared with tempered steel for a number of reasons. For example, the strip is stable in both states and supports its own weight. Thus, a sliding clip or similar means may be provided to enable the device in its extended or rigid state to be clipped to a user's clothing, for example (in the manner of a pen or the like), without the risk of the device accidently moving to the coiled state. Furthermore, such material may be much more durable than tempered steel in that it can be repeatedly moved between the two states without degradation. Similarly, graphene is exceptionally flexible and durable, whilst being 200 times stronger than steel.

(11) Above the bistable layer 18, there may, in some exemplary embodiments of the invention, be a 100 μm thick electro-luminescent display layer 20 and, above that, a 50 μm polyester deep dyed filter layer 22. Finally, there is an anti-moisture ingress coating 24, which may be around 100 μm thick. All of the above-mentioned layers form a composite sandwich-like structure to make up the sprung band 14.

(12) Referring additionally to FIG. 2a of the drawings, the bistable layer 18 has the transverse shape illustrated, that is curved in a gentle arc, when the sprung band 14 is in the above-mentioned first state (i.e. extended and substantially axially straight). When pressure is applied to the ends of the band, and exceeds the yield point of the bistable layer 18, the band 14 moves, under its own tension, into the second, curved state (FIG. 3) and the transverse curve in the bistable layer 18 straightens out. The tension in the bistable layer 18 acts to maintain the band in the curved or “wrapped” state until an opposing force is applied to “peel” it off.

(13) The four layers, excluding the electro-luminescent layer 20, terminate first inside the control unit 12. The electro-luminescent layer 20 continues further into the control unit 12 and adopts its shape. The layer 20 may have a beryllium-copper surface-mounted connector similar to the mounting of an LCD in a mobile phone, for example. This allows the user to have several displays of differing colours and layouts driven from a common driver circuit and battery.

(14) The sprung band 14 may also contain touch sensitive buttons (not shown) to enable a user to control functions of the display apparatus, as required by the application.

(15) It can be seen from FIGS. 1 and 2 of the drawings particularly, that the free end of the sprung band 14, opposite the end at which the control unit 12 is mounted, has tapered side edges along a portion of the length thereof. In the example illustrated, the tapered portion 14a of the band 14 comprises about 40% of the total length of the band 14, but this will be dependent on the material used for, and the width and thickness of, the bistable layer 18 and, therefore, its tensile force when in the above-mentioned first (extended) state. It is this tensile force that dictates the speed at which the band 14 springs or otherwise moves from the first state to the second, curved state shown in FIG. 3 of the drawings.

(16) It will be appreciated by a person skilled in the art that, since a principal objective of the tapered portion 14a of the band 14 is to slow and soften this movement, the required reduction in tensile force in the bistable layer 18 along this portion will accordingly be dependent on the degree to which the tensile force is to be reduced. It will be appreciated by a person skilled in the art that the side edges of the entire band 14 may be tapered to match the tapered edges of the bistable strip 18, as shown in FIG. 1 of the drawings. However, this is not essential, and in other embodiments (as illustrated in FIG. 2 of the drawings), only the bistable strip 18 has a tapered portion 18a, and the strip 18 is embedded or sandwiched within the other layers that are substantially rectangular and not tapered. The present invention is not necessarily intended to be limited in this regard.

(17) Thus, this progressive reduction in tensile force at the end of the band 14 could, for example, be achieved (additionally or alternatively) by a tapering (i.e. progressively reducing) thickness of the bistable layer 18 along the portion 14a toward the free end of the band 14. In the example shown, the reduction in tensile force toward the free end of the band 14 is achieved by inwardly tapering side edges, such that the width of the bistable layer 18 (and, indeed, the entire band 14) is progressively reduced along the portion 14a toward the free end of the sprung band 14. In the specific example shown, the side edges of the end portion 14a of the band 14 taper inwardly (toward the longitudinal axis of the band) at an angle of around 6.5° relative to the axial length of the band 14. However, once again, the specific taper angle will be dependent on the tensile force in the untampered bistable layer 18, the gradual reduction in tensile force required to be achieved, and the length of the portion 14a.

(18) Thus, in this specific example, an object of the invention is achieved by using a 50 μm thick tempered steel bistable layer, which may be between 15 and 40 cm in width. An end portion 14, extending over around 30-45% of the total length of the band 14, may be provided having side edges that taper toward the end at an angle of around 5-10° relative to its axial length. However, it will be appreciated by a person skilled in the art that different materials or thickness of materials used to form the bistable layer 18 may require a different relative length of the tapered portion 14a, a different angle of tapering or, indeed, additional or alternative tapering of the thickness of the bistable layer 18 toward the free end of the band 14, in order to achieve a desired lessening of the tensile force along the portion 14a, and the present invention is not necessarily intended to be limited in this regard.

(19) In use, the band 14 is placed over a user's wrist in its first (extended or flat) state. The user then applies pressure to the ends of the band 14. The sprung band 14 yields to the pressure and moves into the second, coiled state around the user's wrist and, in this form, can be seen most clearly in FIG. 3 of the drawings. The movement from the first to the second state, unlike prior art snap bands, is not a sudden, springing or snapping movement, but a slower, more controlled movement, in view of the tapered side edges, as described above.

(20) The band 14 does not require any latch mechanism, or indeed any other form of retaining means, to hold it in this position, as the tension in the sprung band 14 retains it around the user's wrist until the wearer wishes to remove it.

(21) It will be apparent to a person skilled in the art, from the foregoing description, that modifications and variations can be made to the described embodiments without departing from the scope of the invention as defined by the appended claims.

(22) In particular, as well as variations in the materials used to form the bistable layer 18 and, therefore, the degree to which the tensile force therein needs to be graduated to achieve the desired effect, it will be appreciated that the applications to which the resultant device lends itself, and the functionality that can be incorporated therein, can vary greatly according to requirements. Some configurations of the present invention may include a control unit, as described above, and others may not. The configurations envisaged within the scope of the present invention, and the corresponding technical improvement achieved by the present invention, namely the slowing and softening of the movement of the band between the two states, are particularly advantageous in respect of electronic applications in which any form of electronic component incorporated in the band is protected from degradation and damage that would otherwise be caused by the repeated, often forceful, “snapping of the band between the two states. Where a power supply is required for components within the band, e.g. touch-sensitive control elements, LCD display elements, or even simple LED elements incorporated in the band itself, consideration needs to be given to the manner in which such a power supply will be provided. In the exemplary embodiment described above, a battery is incorporated in a control unit 12 and the electro-luminescent layer defines a connector for carrying power from the battery to the various components incorporated in the layer 20. The layer, 20, is naturally quite fragile and susceptible to damage and the repeated movement thereof between the two band states could, in prior art devices, cause premature failure thereof, whereas the present invention significantly reduces the stress applied to this layer during movement thereof, thus increasing its longevity. In other exemplary embodiments, particularly in the case where a control unit is provided in which all processing/functionality, controls and the device display are provided therein, together with a battery, it may be desirable to provide simple display elements, e.g. LEDs or micro LEDs, in the band itself. Such display elements could be connected to the battery in the control unit via a thin wire or conductive strip extending from the control unit to the elements. Once again, the present invention is highly advantageous in that it minimises the stress to which the conductive wire or strip would otherwise be subjected during state changes, thereby optimising the longevity and reliability of the device. In yet another exemplary embodiment, a flexible battery may be incorporated in the band as one of the layers (in which case, all functionality and controls may be provided within the band itself and the control unit may be omitted in some cases) and, once again, the functionality, structural integrity and life span of such a flexible battery is protected and optimised by the present invention.

(23) For the avoidance of doubt, the present invention may lend itself to a number of different applications, and is not necessarily intended to be limited in this regard. Any level of desired functionality and connectivity can be provided. For example, the device may comprise a music streaming device, including a processor, mobile network connectivity and/or memory, Bluetooth or other connectivity, loudspeaker(s) and/or headphone jack, display elements and controls. All of these components (including the display and control elements) may be provided in a control unit, and the band itself may be entirely passive, or it may include some simple display elements (e.g. LEDs or micro LEDs) as described above. At the other end of the spectrum, all of the functionality, including the display and controls, may be provided as layers of the band, in which case there may be no control unit at all. It is, alternatively envisaged, that the functionality, display and controls of the device may be split between a control unit and the band itself.

(24) More generally, any functionality currently available in computing devices such as smart phones and computer tablets could be incorporated, either wholly or partially within a control unit and/or wearable band. Such functionality may include, but is not limited to, Bluetooth (or other wireless) connectivity, sound sensors and/or loudspeaker(s)/microphone, a micro camera and lens for capturing still or video images, integrated motion sensors, a visual recognition module, Near Field Communications (NFC) capability, biosensors, LTE (e.g. 4G network) connectivity, voice/text communications, etc. Any part of the display and/or controls may be provided in the band itself. Where a control unit is provided, any or all of the functionality, display and controls may be provided therein/thereon. Equally, some exemplary embodiments of the invention may not include a control unit at all, and all functionality, display and controls can be provided in, and supported by, the wearable band. Two-dimensional transistors, flexible PCBs, flexible memory, flexible battery, hybrid electronics (structural/surface/in-mould electronics) and similar technologies may, for example, be utilised in this regard and incorporated in the form of one or more layers within the band. The display may comprise a flexible display on one side, or even both sides, of the wearable band. In any or all cases, the device may incorporate a light sensor to control illumination of the display (whether that is provided on a control unit, on the band itself, or both). The battery, irrespective of the form this may take (if required) may be rechargeable by means of, for example, a conventional charger, conductive charging, or even by means of a solar or thermoelectric cell.