Patent Publication Number: US-2009234503-A1

Title: Automatic switch device by sensing direction for a handheld apparatus having double-sided keypad arrangement

Description:
TECHNICAL FIELD 
     This invention relates to switches, and more particularly to switches controlled by gravity. 
     BACKGROUND OF THE INVENTION 
     With great advance of battery and semiconductor technologies, so many kinds of handheld apparatuses, such as mobile phones, portable multimedia players (PMPs), remote controls, MPS players, personal digital assistants, digital cameras, portable global positioning systems, electronic dictionaries, the SideShow devices used for the VISTA operating system of Microsoft etc., become popular. It is very confused and inconvenient that a user carries or uses various individual handheld apparatuses. Thus, a 2-in-1 integrating approach is adopted by many conventional handheld apparatuses, such as a combination of a SideShow device and a remote control, or a combination of a mobile phone and a PMP. Usually, those 2-in-1 apparatuses arrange keypads of the two combined systems on two opposite side of a cuboidal housing, respectively. When a user holds the 2-in-1 apparatus with his/her palm to operate either of the two systems facing him/her, it will be very possible that the keypad on backward side of another system not being operated is unintentionally pressed. Therefore, undesired operations and unnecessary power consuming of battery will occur. 
     Some handheld apparatuses with double-sided keypad arrangement equip a switch for manually switching a keypad on either side to be enabled and the other one to be disabled, so that it can prevent users from intentional operations to the disabled keypad. However, under this arrangement, every time a user must first operate the switch to enable the keypad of the system he/she wants to use. It is very inconvenient. Further, the switch also tends to be damaged because of frequent operations. 
     SUMMARY OF THE INVENTION 
     A primary object of the invention is to provide an automatic switch device by sensing direction for a handheld apparatus having double-sided keypad arrangement, which can detect directionality of the handheld apparatus to automatically enable the keypad on the upward side (facing the user) and simultaneously to disable the downward keypad (facing the ground or facing outward). An automatic switch without any additional operations can be performed when a user turns over the handheld apparatus. It will be very convenient for users of the apparatuses with double-sided keypad arrangement. 
     In order to accomplish the object abovementioned, the handheld apparatus has a cuboidal housing, whose two opposite sides equip a keypad, respectively. The switch device in the apparatus has a gravity sensor for detecting a distribution of gravity of the apparatus along three coordinate axes. The senor sends a gravity signal to a controller, which judges direction of the apparatus being disposed. The controller sends a switching signal to a relay connected to the two keypads. The relay controls either of the keypads to be available. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  illustrates a handheld apparatus having double-sided keypad arrangement in accordance with the principles of the invention; 
         FIG. 2  illustrates a block diagram of an embodiment in accordance with the principles of the invention; and 
         FIG. 3  is a graph indicating a principle of direction judgment according to the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 1 , a handheld apparatus having double-sided keypad arrangement in accordance with the principles of the invention is shown. The apparatus has a cuboidal housing  1  including a first panel  11  and a second panel  12  which are parallel. Two keypads  111 ,  121  are equipped on the two panels  11 ,  12 , respectively. Of course, other elements, such as a display  112 ,  122 , also can be additionally equipped on the panels  11 ,  12 . 
     Referring to  FIG. 2 , it shows a preferred embodiment according to the invention. There are two independent systems, a first system la and a second system  1   b , in the housing  1 . The two keypads  111 ,  121  belong to the two systems  1   a ,  1   b , respectively. As mentioned above, the two keypads  111 ,  121  are located on two parallel sides of the housing, respectively. A gravity sensor  2 , which can detect a distribution of gravity along three rectangular coordinate axes, is arranged in the housing  1 . The gravity sensor  2  electrically connects to a controller  3 . The gravity sensor  2  sends a gravity signal reflecting the distribution of gravity along three rectangular coordinate axes to the controller  3 . In the embodiment as shown in  FIG. 2 , an output end of the controller  3  electrically connects to control ends  41   a ,  41   b  of a relay  4 . An inverter (NOT gate)  43  is arranged between the two control ends  41   a ,  41   b  to make them be constantly opposite. The two control ends  41   a ,  41   b  control switches  42   a ,  42   b  to open or close, respectively. The two switches  42   a ,  42   b  electrically connect to the first keypad  111  and the second keypad  121 , respectively. The controller  3  judges directionality of the housing  1  according to the gravity signal from the gravity sensor  2 , and then output a switching signal to the control ends  41   a ,  41   b  of the relay  4  to have the two keypads  111 ,  121  enable and disable, respectively. Those skilled in the art will recognize that the term “enable” means the keypads  111 ,  121  are available and “disable” means they are unavailable. The two keypads  111 ,  121  are always under an opposite state. The embodiment shown in  FIG. 2  uses one inverter  43  and two independent single-pole-single-throw (SPST) switches to constitute the relay  4 , but those skilled in the art must know that the relay  4  also can be replaced with any other types, such as single-pole-double-throw (SPDT), double-pole-single-throw (DPST) or double-pole-double-throw (DPDT). If a relay with double pole or double throw is adopted, the inverter  43  can be optionally disappeared by means of a directly inverse switching through the relay. 
     Referring to  FIG. 3 , let&#39;s suppose the housing  1  of the handheld apparatus is in a horizontal position, i.e. its both first panel  11  and second panel  12  are parallel to an x-y plane of a  3  dimensional rectangular coordinate system. Let&#39;s further suppose the first panel  11  is a front and the second panel  12  is a back, i.e. z-axis is in a direction toward the first panel  11 . When the first panel  11  is upward to face a user (not shown) and the second panel  12  is downward to face the ground (not shown), a gravity of −g on z-axis will be detected as shown in  FIG. 3A . (because the gravity is in an opposite direction of z-axis, it becomes negative.) Contrarily, when the housing  1  is turned over with an angle of 180 degrees to make the second panel  11  upward and the first panel  11  downward, z-axis becomes downward as shown in  FIG. 3B . At this time, gravity completely falls on z-axis, but a gravity of +g on z-axis will be detected because the direction of gravity is the same as z-axis. The controller  3  can judge that either the first panel  11  or the second panel  12  is upward according to the principle, and further control the relay  3  to make the upward keypad  111 ,  121  enable and the other one disable. Of course, the abovementioned configuration is suitable for a using mode with the operated panel being upward. If the present invention is utilized in other special using modes, the problem can be simply solved by turning over the coordinate axes or adjusting the judging standard in the controller  3 . Additionally, under a practical situation, the housing  1  of the handheld apparatus may be disposed in any other directions or angles besides horizontal, its detailed judging process will be filed as another individual patent application. In principle, it can be a rough judging standard that the gravity on z-axis is positive or negative. 
     The present invention can automatically switch a keypad on one side being operated to be enabled and the other one to be disabled without manually switching when a user is turning over a handheld apparatus with double-sided keypad arrangement. An unintentional operation to the non-being-operated keypad can be avoided. Therefore it is very convenient for users. 
     An embodiment of the invention has been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are the scope of the following claims.