Patent ID: 12243679

DETAILED DESCRIPTION OF THE INVENTION

In a first aspect a tablet stand is provided which incorporates a near field antenna configuration which couples to a near field antenna in the back of a tablet and provides a near field antenna coupling region for near field communication at the front of the tablet. The stand may be completely passive and use conductive antenna elements and passive resonance matching circuit elements to provide efficient coupling. In another aspect a tablet stand and passive keyboard combination adapted for use with a near field enabled tablet is provided. In another aspect a rotatable mounting bracket with embedded antenna, near field enabled tablet, and passive keyboard combination is provided adapted for converting the tablet into a notebook type configuration.

Referring toFIG.1a combination10of a tablet12mounted in stand14is shown in a side view. Stand14as shown has three sections16,18,20. Section18supports the tablet at a desired angle which may be adjustable. Sections16,18,20may preferably be a single piece construction, for example of plastic, with bendable connections24,25between each section. This allows the stand to be folded flat for compact storage when traveling and/or dimensioned to be a cover for tablet12. If used as a cover the stand may include means to attach to the tablet front, such as magnets or snap fit edges or edge portions (such as holders26illustrated below) or other known connection means allowing easy removal of the cover/stand. Bendable connection24allows section16to be reconfigured from a first position22indicated by the dashed line when near field communication is not needed to a second position in front of the tablet for near field communication at the front of the tablet, as shown by the solid line. Alternatively, however, if portability is not critical the sections16,18,20may be formed of a single solid piece, or only two pieces with section16pivotable about position24to provide a more solid base and allow the reconfiguration noted above. Also, more than three sections may be provided, for example, four sections may be provided with section22being a fourth section for stability and section16reconfigurable on top or below section22or18, when in its first position. One or more of section joining positions24,25,27may be separable so the sections there are movable, not merely bendable, to adjust the stand configuration and tablet support angle. (The part of position24joining sections16and18, however, is not separable unless provisions are made for coupling the embedded antenna across the separation, or through an additional section22via a transmission line, as discussed below. Also, in such an embodiment sections22and16may be a single piece with section18movable to adjust the stand angle.) Separable joining positions may include means to hold the sections in place, including recesses, magnets, snap fit or other means. Tablet12may rest against the stand or may be held in position by a holder26which may have a shape (including a shape extending around the tablet edge in a U shape to form a slot for the tablet edge or a snap fit design) and extension for desired stability. Alternatively, other means such as magnets may be employed to hold the tablet in place. The relative size of the sections may be varied and, for example, section16may be smaller (in length and/or in width).

FIG.2Ais a front perspective view andFIG.2Bis a back view of stand and tablet combination10. Shown in dashed lines inFIG.2Bis a schematic outline of the tablet near field communication antenna28. Tablet12will also include appropriately designed near field reader circuitry. Antenna28may be any of various designs and may be a coil, for example and designed for resonance coupling at the near field communication frequency employed. For example, 13.56 MHz is commonly employed for near field communication using the ISO 14443 standard but various other frequencies and near field communication approaches are possible. Dimensions of antenna28may vary as well as shape so the shape and size shown is schematic in nature and for illustration purposes. As shown section18is configured to overlap with the antenna28position in the tablet. If the antenna28is configured at or near the top of device12section18will therefore extend up to the top of the back of the device or alternatively an additional section of the stand may be provided in this upper area, which is movably coupled to section18. In such case an embodiment of antenna30with two separate near field inductive coupling portions connected by a transmission line, as described below in relation toFIG.7andFIG.8may be preferred for more efficient coupling. This transmission line may pass through the sections necessary to provide coupling at the desired position displaced from antenna28, depending on the specific stand configuration.

Referring toFIG.3the stand14is shown in a top view assuming the sections may fold into a flat configuration as described above. If not the view may be still generally be considered a top view (with relative dimensions and orientations altered accordingly) without affecting the general functional discussion. As shown by the dashed line a passive near field coupling antenna30is embedded in the stand sections16and18. Antenna30may comprise a conductive coil printed or mounted on the sections or a suitable substrate to maintain a thin configuration for stand14, especially for portable applications. A tuning circuit32is provided to match the resonant frequency to that of antenna28with one or more passive elements including a capacitor to form a resonant tank circuit along with the intrinsic antenna inductance. Design of the antenna for most effective coupling to antenna28may employ known near field antenna design teachings, such as in “The RFID Handbook”, by Klaus Finkenzeller, 3rdEd., Wiley Publishing, 2010, the disclosure of which is incorporated herein by reference. As will be appreciated fromFIG.2BandFIG.3the near field coupling antenna30will efficiently couple to the magnetic field from tablet antenna28and will preferably encircle the entire diameter of antenna28to capture substantially all the flux therefrom. The portion of antenna30on the front section16in turn will provide an efficient near field coupling area in front of the tablet. The antenna30area in section16and the antenna area in section18, may be varied. For example, as shown inFIGS.4A and4Bthe antenna configuration in section18may be chosen to match the size of antenna28while the antenna size in section16may be varied up to substantially full width of section16as shown. The antenna Q factor, antenna coupling factor, communication bandwidth and resonance tuning frequency may be considered for optimizing the antenna parameters for the application.

Although section16is shown extending in a front bottom portion of the support surface of stand section18, which is desirable for coupling to a keyboard, in other embodiments where coupling to other portable devices is desired, section16may extend to the side of the support surface to extend beyond the front of the tablet. Also, in such an embodiment section16may slide sideways into the stand section. Therefore, more generally, section16is movable in various ways along with near field coupling antenna30to extend the near field coupling to the portable device to be accessible at the front of the stand.

Referring toFIG.5A, tablet12and stand14are shown configured with a keyboard40adapted for wireless near field communication with tablet12. Keyboard40may employ the teachings of U.S. Pat. No. 7,006,014, the disclosure of which is incorporated herein by reference. Keyboard40will include one or more near field coupling antennas42which are coupled to modulating circuitry in the keyboard to communicate keystrokes to tablet12, typically via load modulation detection in reader circuitry in tablet12. Keyboard40preferably does not have a battery and the keyboard modulator circuitry is powered by the magnetic field from antenna30. Separate antennas42may be provided for simultaneously activated keyboard tags/modulators. For example, separate row and column antennas may be provided which can be simultaneously independently modulated at different sub-carrier frequencies to identify a key. Other examples are described in the '014 patent.

In the configuration shown inFIG.5Aantenna(s)42overlap portion of antenna30in section16of the stand for good near field coupling via antenna30to tablet antenna28. (Means may be provided to hold the keyboard in the stand14in this position if desired, for example, a side bracket on section16, like bracket26described above, may be provided.) If the keyboard has thin profile keys, in particular keys commonly referred to as a scissor switch design, it may have a metallic substrate portion adapted for receiving the scissor switch keys48, for example, a thin aluminum substrate44. This metallic substrate may interfere with the inductive near field coupling and a nonmetallic portion45may be provided and the keyboard near field communication antenna42is configured over the nonmetallic portion45. Non-scissor switch keys47, such as function keys may be provided in this area. Alternatively, a ferrite material46may be provided between keyboard near field communication antenna42and the metallic substrate to reduce negative effects of the metal on the coupling. The ferrite material46may be a separate layer or a coating or part of the antenna structure42. Also, while antenna42is shown above layer44it may be below the layer44with layer46in between.FIG.5Ais therefore highly schematic as many different configurations may be provided. Also, if the ferrite layer is provided adjacent or on the antenna42it will increase the antenna inductance and coupling factor allowing a reduced antenna size. This may be desirable allowing a more compact implementation of the antenna(s) in the keyboard and providing more area for the keys. The ferrite will affect coupling parameters to antenna30and circuitry32may be adjusted accordingly for desired communication. Keyboard40, being wirelessly coupled, may be freely movable as shown inFIG.5Bwith a representative distance D shown for illustration. Since tablet12has typically a relatively small screen a communication distance of comfortable use may be provided (the drawing is not to scale for illustration purposes). An additional coupling antenna43may be provided in keyboard40to enhance read range, as described in the '014 patent. This antenna may be un-modulated by any direct key coupling and may have different dimensions, Q factor and coupling factor than antenna42; therefore this antenna in combination with passive coupling antenna30may thus enhance wireless near field communication with keyboard40and tablet12over a distance otherwise impractical to implement. Although shown below antenna42, antennas42and43may be in a side by side relation. Also, antenna43may have a ferrite material over some or a portion thereof if it overlaps metal layer44. Also, the antenna43may have a ferrite material and be relatively large while antenna(s)42may not, for example, antenna(s)42may be of smaller size and not configured over metal layer44. One illustrative embodiment is shown inFIG.9with a large antenna43partially overlapping metal substrate44(preferably below substrate44) and with partial ferrite layer46in the overlap region. Also, shown are three smaller antennas42coupled to the key modulated RFID tags as schematically shown by arrows49. Three antennas42may allow independent row, column and multi-function key tag connections in an embodiment. Antenna(s)42may overlap antenna43as shown or may be beside antenna43as noted above. In an overlap configuration antenna43may enhance tag coupling parasitically whereas in a non-overlapping configuration a direct connection to the tag(s) power supply is preferably employed.

Referring toFIGS.6A and6Ban alternative embodiment is shown with stand14replaced by a hinged bracket assembly50, shown in side and front perspective views engaged with a tablet12and keyboard40. The rotatable mounting bracket50, with embedded antenna30, near field enabled tablet12, and passive keyboard40combination as provided is adapted for easily converting the tablet into a notebook type configuration. No direct electrical connections are required to tablet12or keyboard40to convert the tablet into a notebook configuration, the two devices may simply be inserted into the two sides of mounting bracket50.

Bracket assembly50may include two rotatably connected slotted sections adapted to receive tablet12and keyboard40, respectively. For example, rotatable connection may be via hinges52fixed to one section (e.g., bottom keyboard receiving section) and pivotably mounted to the other section. Other hinge designs are possible, however. Near field coupling antenna30may be configured across the two sections through hinges52. For example, the top and bottom portions of the antenna ofFIG.3may pass through the respective hinges52.

In an embodiment, bracket assembly50may be integrated with keyboard40with a receptacle to receive tablet12. In this case antenna(s)42(or43) and30need not be separate antennas. Also, the rotatable assembly may be configured to rotate to a flat configuration aligned with the plane of the keyboard for portability. This flat configuration may be from folding the assembly50toward the keyboard to the sides or recesses therein, or to the front of the keyboard.

Alternatively coupling antenna30may comprise two antennas30A and30B, on the tablet receiving and keyboard receiving sections of bracket50, respectively, which are coupled together. For example, as shown inFIG.7a thin transmission line60may couple the two antennas30A and30B, through one of hinges52. (Transmission line60may for example be designed to be 50 Ohms, but other designs are possible.) The coupling of the two antennas30A and30B to the transmission line is schematically shown provided by the inductor (loops) on the ends of the transmission line. Coupling may be implemented in various ways to provide efficient coupling and impedance matching.

Alternatively, the two antennas30A and30B may couple inductively through adjacent positioning of respective edge portions of the antenna coils at the mating edge of bracket assembly50so that no wiring need pass through hinge52. Also, inductive coupling may be provided at the hinges. Also, near field coupling antenna30A or30B within one or both of hinges52may include a ferrite material to enhance coupling for a smaller coil geometry or if part of the hinge is composed of metal. Also, one hinge may include a ferrite material and coil and the other hinge a non-ferrite coil. For example, the ferrite coil may couple to antenna43and the non-ferrite coil to antenna(s)42. Also, in an embodiment the coil may wind about a ferrite cylinder shaped piece forming part of the hinge spindle or axle.

It should be noted that a two antenna design30A,30B may also be provided in the prior embodiments of stand14instead of a single antenna design (with direct inductive coupling or via a strip line as illustrated inFIG.7andFIG.8). This may prevent antenna damage due to folding of the stand over time. Also, this may provide more efficient coupling where one or both of antenna portions30A,30B are desired to be smaller and spaced a distance apart.

The above embodiments are non-limiting and various modifications may be for specific implementations and such are within the scope of the invention. Also, the drawings are not to scale and are not meant to limit relative dimensions of illustrated components.