Abstract:
The present invention is a mobile handheld communications devices with a light emitting diode (LED) that outputs sufficient light to illuminate an area external to the case and a switch to control the LED. An LED that outputs sufficient light to illuminate an area external to the case can be added to any mobile handheld communications device, including pagers, telephone handsets, and personal digital assistants (PDAs).

Description:
FIELD 
     The present invention relates generally to electronics, and more particularly to mobile hand held communications devices. 
     BACKGROUND 
     When talking on a mobile handset it can be difficult to perform manual tasks since the user generally can not have both hands free without running the risk of dropping the mobile phone. A particular problem occurs when the user needs to hold another device. In one example, the user may wish to perform tasks that require additional lighting while talking on a mobile phone or using a personal digital assistant (PDA). Such additional lighting may be desirable when performing such tasks as writing directions or reading a map while driving at night, or trying to unlock a door in the dark. While performing these tasks the users will only have one hand free making it difficult to hold both a light and the mobile phone while performing the additional task. 
     It is common to use a flashlight to perform tasks when additional light is needed. Many flashlights of various sizes and shapes are available and well known, but none of these meet the requirement of being easy to use while talking on a mobile phone and trying to perform manual tasks. In addition, many mobile phone and PDA users may not want to carry a flashlight. 
     SUMMARY 
     It is therefor an object of the present invention to provide a handheld communication device or PDA that enables a user to conveniently provide illumination. The present invention provides a handheld device with a lamp positioned to illuminate an area external the handheld device. In one embodiment the lamp is a light emitting diode (LED) constructed to output sufficient light to illuminate an area external to the case and a switch to control the LED. In a preferred embodiment the LED may be a super-bright or ultra-bright LED. The lamp may be added to any mobile handheld communication device, or PDA, including pagers and telephone handsets. 
     Advantageously, the lamp enables a user to conveniently provide illumination using the handheld device such as a mobile handset or PDA. Accordingly the user may more safely and confidently perform manual tasks while using the handheld device without the risk of holding a flashlight as another light source. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS AND TABLES 
     For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: 
     FIG. 1 is a front view of a light emitting handset in the form of, a wireless telephone handset with a light emitting diode (LED) located in the lower portion of the light emitting handset, with a lens in the lower side wall. 
     FIG. 1A is a detail view of the LED located in the lower portion of the light emitting handset, with a lens in the lower side wall of the wireless telephone handset. 
     FIG. 1B is a detail view of the LED, lens, and foucusing reflective surface. 
     FIG. 2 is a circuit diagram showing an embodiment of the light emitting handset wherein multiple LED&#39;s are driven by a power supply. 
     FIG. 3 is a circuit diagram for another embodiment of the light emitting handset wherein one LED is capable of being turned off independent of another LED. 
     FIG. 4 is a front view of a light emitting handset in the form of a telephone handset with an LED located in the upper side wall. 
     FIG. 5 is a circuit diagram for another embodiment of the light emitting handset wherein the intensity of the LED can be varied. 
     FIG. 6 is a circuit diagram for another embodiment of the light emitting handset wherein the intensity of the LED can be varied by using multiple resistors. 
    
    
     Use of the same reference symbols in different figures indicates similar or identical items. 
     DETAILED DESCRIPTION 
     Referring now to FIG. 1, an embodiment of the mobile handheld communications device  10  is shown in the form of a light emitting telephone handset. The mobile handheld communications device  10  includes a case  36 , a lamp receiving area  21 , a lamp in the form of a light emitting diode (LED)  14 , and a switch  23  for controlling the LED  14 . While FIG. 1 shows a single LED, it will be appreciated that multiple LED&#39;s can be used. In FIG. 1 the mobile hand held communications device  10  is a light emitting telephone handset; however, the hand held communications device can be any hand held communications device, such as a pager. Alternatively, the device may be a PDA. It will be appreciated that other handheld portable electronic devices may advantageously be used. The mobile handheld communications device  10  has an upper speaker portion  41 , a lower microphone portion  45 , and places the LED  14  in the lower microphone portion  45  of the mobile handheld communications device  10 . It will be appreciated that the elements may be alternatively arranged on the mobile handheld communications device  10 . 
     Shown on FIG. 1, the case  36  has a top surface  54 , a bottom surface  58 , a first side wall  63 , second side wall  67 , an upper side wall  72 , and a lower wall  76 . Preferably the LED  14  is located on the lower side wall  76  and positioned and aimed relative to the speaker and microphone so that the light beam  32  of the LED  14  points in front of a user when a user is conversing on the mobile handheld communications device  10 . More specifically, the light beam  32  points in a direction generally parallel to the top surface  54 , the bottom surface  58 , the first side wall  63 , and the second side wall  67 . It will be appreciated that other light beam  32  orientations may be desired for specific applications. The light beam  32  projects on to a target surface  37  creating the illuminated area  43  with a focus area  35  within the focus area. 
     In one example, a user might try to talk on a phone and unlock a door at the same time. If the LED  14  is located on the lower side wall  76 , the user can easily point the light beam  32  in the direction of the door knob while talking on the telephone handset  10 . In another example, the device can be used to illuminate a map or other reading or writing surface while talking on the mobile handheld communications device  10 . 
     The switch  23  may be located anywhere on the case  36 . In one embodiment the switch  23  is located on the first side wall  63 . This location has the advantage of being easily operated by the user&#39;s little finger while talking on the phone. Additionally, there may be a second switch  27 . The second switch  27  may be located on the second side wall  67 . Having a switch on both side walls allows the light to be easily operated by the little finger on either hand. Alternatively, activation of the light source can be based on the depression of an existing key for a minimal dwell time. For example, in one embodiment a user can hold the “*” key for two seconds to activate and deactivate the light. 
     The LED  14  can be any color available, though white is preferred. In applications where the user wants to maintain night vision several choices are available. Red has traditionally been considered the best choice for retaining night vision, however, many pilots and the military now prefer green. Green is good for maintaining night vision and it does not make it difficult to see red lines on maps and charts. Blue is another possible choice. It is easy on the eyes and can lessen eyestrain. In addition the switch can be adapted to vary the intensity of the LED  14 . It will be appreciated that other colors or frequencies may be selected for an aesthetic or application specific purpose. 
     Referring now in particular to FIG. 1A, a detail view of the LED  14  is shown. The LED  14  includes a first lead  89  and a second lead  87  for supplying power to the LED  14 . The mobile handheld communications device  10  preferably has some method of focusing the light from the lamp onto a target surface. In this regard, the LED  14  also includes an encapsulation  85  that acts as a focusing element to concentrate the light into an illuminating beam. 
     Alternatively, the light beam can be focused as shown in FIG.  1 B. In FIG. 1B the light can be focused into an illuminating beam by using a lens  93  or by using a focusing reflective surface  97 . The lens  93  or the focusing reflective surface  97  may be built into the lamp or external to the lamp. The light can also be focused by some combination of lens  93  and focusing reflective surface  97  built into the lamp and external to the lamp including multiple lenses  93  and multiple focusing reflective surfaces  97 . FIG. 1B also shows the lamp receiving area  21 . The lamp receiving area  21  is a portion of the mobile handheld communications device  10  adapted to accept the lamp. 
     The lamp, in this case an LED  14 , should be able to create a focus pattern of sufficient strength to illuminate a portion of the target surface at a useful distance. Sufficient strength would be enough light to enable a person to visibly perceive the illuminated area in otherwise dimly lit environment. Accordingly the person is able to perform tasks with the additional illumination provided by the beam. Examples would include the ability to enable a user to identify a key hole or the ability to read twelve point font on a map. Depending on the application, useful distance would be between one and four feet. 
     As shown in FIG. 1, a lens  18  may be added for three purposes, to focus the light beam  32 , to protect the lamp, and to change the color of the light beam  32  by the mobile handset. 
     Referring now in particular to FIG. 2, a circuit diagram for an embodiment wherein multiple LED&#39;s are driven by a power supply will be discussed. This embodiment may be preferable in power sensitive applications. As the number of LED&#39;s increase the power consumed in the resistor decreases. It will be appreciated by one skilled in the art that the number of LED&#39;s can not be increased without bound and that the resistance of the resistor  104  will need to be lowered as the number of LED&#39;s is increased. 
     FIG. 2 shows a power source  100  coupled to several switches  23 ,  27 ,  126  and ground  122 . The power source  100  supplies power to a resistor  104  and several LED&#39;s  108 ,  113 ,  117  that are coupled to ground  122 . When at least one of the switches  23 ,  27 ,  126  are on, current flows through the circuit of FIG.  2 . All of the elements in FIG. 2, except the switches  23 ,  27 ,  126  are connected in series so that the voltage drop across the resistor  104  is minimized. This minimizes the power consumed by the resistor  104 . 
     It is possible for a single switch  23  to be used to control the LED. This would be less expensive than having two or more switches  23 ,  27 ,  126 . But multiple switches may provide greater flexibility and utility. Additionally, having a single switch would require fewer openings in the case  36 . It will be appreciated that other switch arrangements may be used. 
     FIG. 2 also shows a processor  137 . A program adapted to run on the processor  137  may be incorporated to control the switch  126  that turns the LED&#39;s  108 ,  113 ,  117  on and off. If a processor  137  is used software settings can be used to enable the LED&#39;s  108 ,  113 ,  117 . Through the use of a processor  137  many different features are possible, for example, the LED&#39;s  108 ,  113 ,  117  can be turned on for a predetermined amount of time, the LED&#39;s  108 ,  113 ,  117  can be turned on at a predetermined time, or the processor can be used to flash the LED&#39;s  108 ,  113 ,  117  on and off. In addition, the intensity of the LED can be adjusted by varying the on-off duty cycle produced by the processor. One of the benefits of this is power consumption can be reduced. FIG. 2 also shows circuitry detail  141 . Circuitry detail  141  will be described further with reference to FIG.  5 . It will be apparent by one skilled in the art that the processor  137  could be a microprocessor, a microcontroller, a programmable logic device, an application-specific integrated circuit (ASIC), or discrete components. 
     Referring now in particular to FIG. 3, a circuit diagram for an embodiment wherein LED&#39;s  108 ,  113 ,  117  are driven by a power supply  100  with one LED  117  capable of being turned off separate from the other LED&#39;s  108 ,  113  will be discussed. FIG. 3 is similar to FIG.  2 . Two components have been added. A fourth switch  133  connected to LED&#39;s  113 ,  117  and resistor  130  coupled to ground  122  and the forth switch  133 . This embodiment allows one of the LED&#39;s  117  to be turned off while the other two are on. It will be appreciated by one skilled in the art that many different circuit configurations are possible. 
     Referring now in particular to FIG. 4, an embodiment showing a mobile handheld communications device will now be described. FIG. 4 shows an embodiment wherein the LED  14  is located in the upper speaker portion  41  of the telephone hand set  10 . This embodiment would be preferred for applications where the telephone handset  10  is going to be used as a flashlight while not being used as a telephone. The user would have a tendency to hold the telephone handset  10  in their hand in the same orientation as when they talk on the telephone. With the LED  14  in the top of the telephone handset  10  the user can easily point the light in the direction desired by pointing their arm in the direction that they want the light to point. It will be understood that the telephone handset  10  may be any mobile handheld communications device or PDA. 
     Referring now in particular to FIG. 5, a circuit diagram showing circuit detail  141  for an embodiment wherein the switches  23 ,  27 ,  126  are replaced by a switch  150  and the resistor  104  is replaced by a potentiometer  153  configured to vary the intensity of the LED&#39;s  108 ,  113 ,  117 . As the resistance is changed the intensity of the LED&#39;s  108 ,  113 ,  117  will change. 
     Referring now in particular to FIG. 6, a circuit diagram showing circuit detail  141  for an embodiment wherein the switches  23 ,  27 ,  126  are replaced by a selector switch  173  and resistor  104  is replaced by several resistors  177 ,  179 ,  184 . Each resistor  177 ,  179 ,  184  can be a different value. The resistor  177 ,  179 ,  184  selected by the selector switch  173  determines the intensity of the LED  14 . FIG. 6 shows an example with a selector switch capable of selecting one of three resistors. In theory any plurality of resistors is possible. Some limitations on the number of resistors used include the availability of a selector switch  173  with the desired number of selections, and space constraints of the mobile communications device. 
     The description and drawings contained herein are particular embodiments of the invention and are representative of the subject matter broadly contemplated by the invention. However, the invention encompasses other embodiments that will be apparent to those skilled in the art. Accordingly, the scope of the invention is limited only by the appended claims.