Abstract:
A rechargeable electronic device system including a charging device and a rechargeable electronic device. The charging device includes at least one laser source. The rechargeable electronic device is mounted in the charging device. The rechargeable device includes a rechargeable battery and at least one photovoltaic receptor. The at least one laser source is aligned with the at least one photovoltaic receptor such that the at least one laser source emits laser light to the at least one photovoltaic receptor. The at least one photovoltaic receptor converts laser light to energy used to recharge the rechargeable battery.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to rechargeable electronic devices, and more particularly to a method and apparatus for recharging batteries used to power a rechargeable electronic device, such as a wrist watch computer.  
         [0003]     2. Description of the Related Art  
         [0004]     Rechargeable electronic devices use rechargeable batteries, such as NiCd (nickel cadmium), NiMH (nickel-metal hydride) and lithiuim-based batteries. Conventionally, the rechargeable batteries are recharged by supplying current through wires that are connected to the electronic device. The electronic device may have external electrical contacts for receiving electrical energy from an external power supply to recharge the batteries. Such external electrical contacts may be prone to poor performance, or even failure, due to becoming dirty or corroded. Further, electrical contacts are undesirable for use with electronic devices that are exposed to water, because the electrical contacts make the electronic device difficult to water proof.  
         [0005]     Alternatively, contact-less charging using induction has been used in electronic devices, such as motorized toothbrushes and cordless phones. According to this conventional method, an inductively rechargeable electronic device is placed in an inductive charger. The inductive charger includes a primary coil and the electronic device includes a secondary coil. Alternating current flows through the primary coil of the inductive charger, causing a varying magnetic field that is used by the secondary coil in the electronic device to generate energy. The energy generated by the secondary coil is then used to charge the battery in the electronic device.  
         [0006]     Although inductive charging obviates the need for contacts, such a method is not practical for use with smaller electronic devices because such devices do not have enough space to fit a coil large enough to generate energy to charge a battery. Further, the coil may interfere with the ability of the electronic device to communicate using radio frequency.  
       SUMMARY OF THE INVENTION  
       [0007]     An object of the present invention is to provide an apparatus and method for recharging a rechargeable battery within a small electronic device.  
         [0008]     Another object of the present invention is to provide an apparatus and method for recharging a battery within an electronic device that eliminates the need for electrical contacts between the electronic device and a charging device.  
         [0009]     Another object of the present invention is to provide an apparatus and method for recharging a battery within an electronic device that allows for the electronic device to be waterproof.  
         [0010]     An exemplary embodiment of the rechargeable electronic device system of the invention includes a charging device and a rechargeable electronic device. The charging device includes a plurality of laser sources. The rechargeable electronic device is mounted in the charging device and includes a rechargeable battery and a plurality of photovoltaic receptors. The plurality of laser sources of the charging device is aligned with the plurality of photovoltaic receptors of the rechargeable electronic device such that the plurality of laser sources emits laser light to the plurality of photovoltaic receptors. The plurality of photovoltaic receptors convert the laser light to energy used to recharge the rechargeable battery.  
         [0011]     According to an exemplary embodiment of the invention, the rechargeable electronic device is a wrist watch. The wrist watch can have photovoltaic receptors arranged on the bezel of the wrist watch.  
         [0012]     An exemplary embodiment of the method for recharging a rechargeable electronic device of the invention includes aligning a plurality of laser sources arranged on a charging device with a plurality of receptors arranged on the rechargeable electronic device. Laser light is emitted from the plurality of laser sources on the charging device to the plurality of receptors. The laser light is converted into energy for recharging the rechargeable electronic device. The rechargeable electronic device is charged using the energy converted from the laser light.  
         [0013]     These and other objects, features and advantages of the present invention will become apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings.  
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0014]     The invention will be described in detail in the following description of preferred embodiments with reference to the following figures wherein:  
         [0015]      FIG. 1  shows an exemplary embodiment of the rechargeable wrist watch system according to the invention;  
         [0016]      FIG. 2  shows an exemplary embodiment of the rechargeable wrist watch according to the invention;  
         [0017]      FIG. 3  is a block diagram illustrating the internal components of an exemplary embodiment of the wrist watch according to the invention;  
         [0018]      FIG. 4  shows an exemplary embodiment of the charging device according to the invention;  
         [0019]      FIG. 5  shows an exemplary embodiment of the opaque shield useable with the various exemplary embodiments of the rechargeable electronic device system according to the invention; and  
         [0020]      FIG. 6  is a cross sectional view of an exemplary embodiment of the charging device according to the invention.  
     
    
     DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0021]     The various exemplary embodiments of the systems and methods according to the present invention are described below with respect to recharging a rechargeable wrist watch, particularly an “intelligent” wrist watch that is capable of wirelessly accessing information from a network and other devices, as well as performing a variety of desktop PC-like functions. However, it should be appreciated that the systems and methods according to the various exemplary embodiments of the invention can be applied to recharging any battery powered device having a rechargeable battery, such as, for example, a pager, a cellular phone, or a digital camera.  
         [0022]      FIG. 1  shows one exemplary embodiment of the rechargeable wrist watch system  1  according to the invention. As shown in  FIG. 1 , the rechargeable wrist watch system  1  includes a rechargeable wrist watch  100  and a wrist watch charging device  200 .  
         [0023]      FIG. 2  shows an exemplary embodiment of the rechargeable wrist watch  100  according to the invention. The wrist watch  100  includes a casing  110 , a watch face  120 , a bezel  130  and a wrist band  140 . The bezel  130  surrounds the watch face  120 . The casing  110  is attached to the watch band  140 , which in turn can be used to strap the wrist watch  100  to the wrist of a user. A plurality of photovoltaic receptors  150  are disposed on the upper surface  135  of the bezel  130 . As shown in  FIG. 2 , the photovoltaic receptors  150  are arranged in semicircular patterns around the bezel  130 . However, it should be appreciated that, in other embodiments of the invention, the photovoltaic receptors  150  could be arranged in any other shaped pattern around the bezel  130 .  
         [0024]      FIG. 3  is a block diagram illustrating internal components of the wrist watch  100 . As shown in  FIG. 3 , the wrist watch  100  includes the plurality of photovoltaic receptors  150 , a battery management circuit  160 , a DC to DC voltage regulating circuit  170 , a rechargeable battery  180  and various electrical/electromechanical components  190  that allow the wrist watch  100  to function as a time-keeping device, access information from a network and/or other devices, and perform a variety of PC-like functions. For example, the components  190  could include a communication interface  195  having GPS (Global Positioning System) and mobile phone communication capability.  
         [0025]     Although only one battery  180  is shown in  FIG. 3 , it should be appreciated that there may be more than one battery  180 . The battery  180  can be any known rechargeable battery, such as, for example, a lithium based rechargeable battery, a NiCd rechargeable battery, or a NiMH rechargeable battery. The photovoltaic receptors  150  can be any suitable photovotaic receptors, such as GaAs (gallium arsenide) photovoltaic receptors.  
         [0026]     The battery management circuit  160  can be any conventional battery management circuit that properly charges the battery  180  and protects the battery  180  from overcharging. For example, the battery management circuit can include any suitable voltage decreasing or voltage increasing circuitry, as needed, to match the voltage output of the photovoltaic receptors  150  to the charging voltage needed to recharge the battery  180 .  
         [0027]     The DC to DC voltage regulating circuit  170  can be any conventional voltage regulating circuit that provides a relatively constant output DC voltage to the wrist watch components despite the declining voltage input it receives from the rechargeable battery  180  over time.  
         [0028]      FIG. 4  shows an embodiment of the charging device  200 . The charging device  200  includes a lower base  210 , an upper base  220 , and opaque shields  230  and  240 . The opaque shields  230  and  240  connect the lower base  210  to the upper base  220 . The upper base  220  includes a plurality of laser sources  225  arranged in semicircular patterns to correspond to the semicircular patterns of the photovoltaic receptors  150  arranged around the bezel of the wrist watch  100 . It should be appreciated that, in other embodiments, the plurality of laser sources  225  can be arranged to correspond to any other pattern of the plurality of photovoltaic receptors  150 . As explained more fully below, the wrist watch  100  can be placed on the lower base  210  of the charging device  200  so that the plurality of laser sources  225  of the upper base  210  align with the plurality of photovoltaic receptors  150  of the wrist watch  100 .  
         [0029]     The charging device  200  may be supplied with power for the laser sources  225  from any suitable external electrical power source. Alternatively, the charging device  200  may include at least one disposable or rechargeable battery located within the charging device  200 .  
         [0030]     The charging device  200  may also include a switch  260  for turning on and off the laser sources  225 . The switch may be activated manually by a user. Alternatively, for better safety, the switch may be activated by the wrist watch  100  when the wrist watch  100  is placed on the lower base  210  of the charging device  200 . Any suitable sensor/switch circuitry may be used for the switch  260 , such as, for example, circuitry using a photointerrupter.  
         [0031]      FIG. 5  shows the opaque shield  230 . The opaque shields  230  and  240  contain the laser light emitted from the laser sources. The opaque shields  230  and  240  can be made of any suitable opaque material, such as, for example, plastic. Opaque shield  230  is identical to opaque shield  240 , so that further description of the opaque shield  240  is omitted. As shown in  FIG. 5 , the opaque shield  230  includes an inner wall  232 , an outer wall  234 , and side walls  236  and  238 . The outer wall  234  forms a section of a circular shape having a diameter slightly larger than that of the bezel of the wrist watch  100 . The inner wall  232  forms a section of a circular shape concentric with the section of the circular shape formed by the outer wall  234 . The section of the circular shape formed by the inner wall  232  has a diameter slightly smaller than that of the bezel of the wrist watch  100 . The inner wall  232  and the outer wall  234  are attached to one another by the side walls  236  and  238 .  
         [0032]      FIG. 6  is a cross sectional view of the charging device  200 . As shown in  FIG. 6 , the inner wall  232  does not contact the lower base  210 , so that a gap  250  is formed between the inner wall  232  and the lower base  210 . The plurality of laser sources  225  are arranged between the inner wall  232  and the outer wall  234 , so that laser light emitted by the laser sources  225  is contained between the inner wall  232  and the outer wall  234 . As illustrated in  FIG. 6 , the gap  250  is large enough so that the bezel  130  of the wrist watch  100  can be placed underneath the inner wall  232 . There is just enough space between the opaque shields  230  and  240  to allow the wrist band  140  to lay flat on the lower base  210  when the watch casing  110  is placed between the opaque shields  230  and  240 . Thus, the spacing of the opaque shields  230  and  240  automatically aligns the photovoltaic receptors  150  arranged on the bezel  130  of the wrist watch  100  with the laser sources  225  when the watch casing  110  is placed between the opaque shields  230  and  240 .  
         [0033]     The laser sources  225  can be any suitable laser sources, such as, for example, GaAs laser sources. However, from a safety perspective, the laser sources  225  should be low power, preferably operating at about 1 mW or less. The photovoltaic receptors  150  can be tuned to the precise wavelength of the laser light emitted by the laser sources  225 . Thus, the photovoltaic receptors can be quite efficient, converting a large fraction of the incident laser light into energy to be used to charge the battery  180 . For example, several hundred laser sources  225  can be used in conjunction with several hundred corresponding photovoltaic receptors  150  to recharge a battery in a few hours time.  
         [0034]     In operating the rechargeable wrist watch system  1 , a user places the wrist watch  100  into the charging device  200  so that the photovoltaic receptors  150  on the bezel  130  of the wrist watch  100  are aligned below the laser sources  225  of the upper base  220  of the charging device  200 . The user then activates the switch  260 , or alternatively the switch is automatically activated by the switch sensing the presence of the wrist watch  100  on the lower base  210 . When activated, the laser sources  225  of the charging device  200  emit laser light down onto the photovoltaic receptors  150  of the wrist watch  100 . The laser light is converted into energy by the photovoltaic receptors  150 . The energy is then used to charge the battery  180  of the wrist watch  100 .  
         [0035]     In other embodiments of the invention, the laser sources  225  of the charging device  200  can be used to input data to the wrist watch  100 . For example, the laser sources  225  can be controlled to modulate the laser light so as to download digital data to the wrist watch  100  through the photovoltaic receptors  150 . The digital data can include information such as, for example, address and telephone entries, scheduling information, and budgeting details. In embodiments of the invention, the charging device  200  includes multiple laser sources  225 . Thus, by modulating the laser sources  225 , the charging device  200  is able to independently download to the wrist watch  100  a large amount of different types of digital information at once.  
         [0036]     Although the illustrative embodiments have been described herein with reference to the accompanying drawings, it is to be understood that the present invention and method are not limited to those precise embodiments, and that various other changes and modifications may be affected therein by one of ordinary skill in the related art without departing from the scope or spirit of the invention. All such changes and modifications are intended to be included within the scope of the invention as defined by the appended claims.