Abstract:
A computer input method includes obtaining a time interval elapsed between a current single touch and a last single touch both on a designated object upon detecting the current single touch, comparing the time interval with a predetermined reference time, and switching a pointing input of the computer input method between an absolute coordinate mode and relative coordinate mode depending on the time comparison result.

Description:
BACKGROUND 
     The present invention relates generally to human input devices for computing systems, and, more particularly, to a computer pointing device. 
     One of the most popular ways to position a cursor on a computer display is to use a mouse, which functions by detecting two dimensional motions relative to its supporting surface. Physically, a mouse comprises an object held under one of a user&#39;s hands, with one or more buttons. Clicking or hovering (stopping movement while the cursor is within the bounds of an area) can select files, programs or actions from a list of names, or (in graphical interfaces) through small images called “icons” and other elements. For example, a text file might be represented by a picture of a paper notebook, and clicking while the cursor hovers over this icon may cause a text editing program to open the file in a window. 
     However, conventional mice employ a relative coordinate system to position cursors. In a relative coordinate system, a cursor&#39;s coordinates are derived from the cursor&#39;s last coordinates and the mouse&#39;s travel distance, angle and speed. If an icon is on one side of a display while the cursor&#39;s last location is on the other side of the display, a computer user would have to drag the mouse over a sizable distance or with high speed to move the cursor over to the icon. In contrast, in an absolute coordinate system, a cursor&#39;s coordinates are derived directly from the mouse&#39;s current coordinates regardless of its last location. By employing absolute coordinate system, a computer user can directly place a cursor at a desired location without mouse dragging movement. 
     As such, what is desired is a computer pointing device that can automatically switch between relative coordinate mode and absolute coordinate mode. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  illustrates a computer input device with a designated touch sensing area for providing pointing input according an embodiment of the present invention. 
         FIG. 2  illustrates correspondence between corners of the touch sensing area of the computer input device of  FIG. 1  and corners of a computer display the computer input device is associated with. 
         FIG. 3  is a flow chart diagram illustrating operational steps for switching the computer input device between absolute coordinate mode and relative coordinate mode according to an embodiment of the present invention. 
         FIG. 4  is block diagram illustrating a computer system that includes a computer input device of the present invention. 
     
    
    
     The drawings accompanying and forming part of this specification are included to depict certain aspects of the invention. A clearer conception of the invention, and of the components and operation of systems provided with the invention, will become more readily apparent by referring to the exemplary, and therefore non-limiting, embodiments illustrated in the drawings, wherein like reference numbers (if they occur in more than one view) designate the same elements. The invention may be better understood by reference to one or more of these drawings in combination with the description presented herein. 
     DESCRIPTION 
     The present invention relates to a computer input device utilizing a touch sensing device for pointing that can be automatically switched between absolute coordinate mode and relative coordinate mode operations. Preferred embodiments of the present invention will be described hereinafter with reference to the attached drawings. 
       FIG. 1  illustrates a computer input device  100  with a designated touch sensing area  112  for providing pointing input according an embodiment of the present invention. The computer input device  100  is a mouse-and-keyboard combo device as described in a patent application Ser. No. 13/341,913 by the same inventor, and the content of which is incorporated herein in its entirety. 
     As shown in  FIG. 1 , the computer input device  100  has a plurality of keys  105 , which overlays the designated touch sensing area  112 . Only touches within the designated touch sensing area  112  can be detected. There are numerous ways to detect the touches, such as infrared light emitting diodes (LED), capacitive or resistive touch pad. In embodiments, a peripheral area marked by the shaded area  115  is designated to be an area for entering absolute coordinates. The reason that only the peripheral area  115  is designated for entering absolute coordinates is because on a computer display, menu items are generally displayed on edges of the display. When a computer user wants to place a cursor over a menu item displayed on an edge, he or she can touch a corresponding spot in the peripheral area  115 , which will result in the cursor being placed directly in a vicinity of the menu item through an absolute coordinate mode operation. Then the user can slightly move the cursor exactly over the menu item through a relative coordinate mode operation. With a conventional mouse, the computer user would have to drag the mouse over a distance to move the cursor over the menu item. In other embodiments, the absolute coordinate entering area is not restricted to the peripheral area  115 , and can be any other or even the entire area of the touch sensing area  112 . 
     However, not every touch on the absolute coordinate entering area will generate absolute coordinates. Other conditions which will be described hereinafter, have to be met before the computer input device  100  switches from a default relative coordinate mode to the absolute coordinate mode operation. 
       FIG. 2  illustrates correspondence between corners of the touch sensing area  112  of the computer input device  100  of  FIG. 1  and corners of a computer display  200  the computer input device  100  is associated with. The touch sensing area  112  has four corners respectively labeled as A, B, C and D. The computer display  200  has a display area  205  which has four corners respectively labeled as A′, B′, C′ and D′. During a setup process, a computer user first moves a cursor to corner A′ of the display area  205 , and then presses a key at the location of corner A of the touch sensing area  112 . In such a way, corner A of the touch sensing area  112  is set to correspond to corner A′ of the display area  205 . Corner B, C and D of the touch sensing area  112  can be set to correspond to corner B′, C′ and D′ of the display area  205 , respective, in the same manner. In other embodiments, touching a corner of the touch sensing area  112  in combination with pressing a dedicated key other than the key at the touched corner may also enact the correspondence between two corners. In other embodiments, a correspondence can be set between any spot on the touch sensing area  112  and any spot on the display area  205 . 
       FIG. 3  is a flow chart diagram illustrating a process  300  for switching the computer input device  100  between absolute coordinate mode and relative coordinate mode according to an embodiment of the present invention. First of all, the process  300  is active only during a pointing or mouse operation that is when a single touch on the touch sensing area  112  is detected. When two or more touches on the touch sensing area  112  are detected, or no touch is detected at all, the computer input device  100  enters keyboard operation. 
     Referring again to  FIG. 3 , the switching process  300  begins with detecting any single touch occurred on the peripheral area  115  in step  310 . In case there is no touch on the peripheral area  115 , the computer input device  100  enters relative coordinate mode in step  370 , and then go back to step  310 . In this case, there must be a single touch on the rest of the touch sensing area  112  for the computer input device  100  to be operating in a mouse operation. In case a single touch on the peripheral area  115  is detected in step  310 , the process  300  obtains a time interval (ΔT) elapsed between a last single touch and the current single touch in step  320 . Here the last single touch can be anywhere within the touch sensing area  112 . The elapsed time interval, ΔT, is then compared with a predetermined reference time, Tref, in step  330 . In embodiments, the predetermined reference time, Tref, is set at two seconds. During the elapsed time interval, ΔT, two or more touches on the touch sensing area  112  may occur and is not considered as a last single touch. If ΔT&gt;Tref, the computer input device  100  enters absolute coordinate mode in step  360 , and then go back to step  310 . If ΔT≦Tref, the process  100  obtains a distance (ΔL) between the last single touch and the current single touch in step  340 . The distance, ΔL, is then compared with a predetermined reference distance, Lref, in step  350 . In embodiments, the predetermined reference distance is set at 60 millimeters. If ΔL&gt;Lref, the process  100  enters absolute coordinate mode in step  360 , and then goes back to step  310 . If ΔL≦Lref, the process  300  enters relative coordinate mode, and then goes back to step  310 . 
       FIG. 4  is block diagram illustrating a computer system  400  that includes a computer input device  410  of the present invention. The computing system  400  includes an input device  410 , a central processing unit (CPU)  420 , a display  430  and a memory and storage unit  440 . The input device  410  comprises a conventional keyboard  412 , a touch sensor  415  and a micro processing unit (MPU)  418 . The touch sensor  415  overlays the conventional keyboard  412  and performs the touch sensing as depicted in  FIGS. 1-3  and associated descriptions. The conventional keyboard  412  and the touch sensor  415  form a keyboard-mouse combo device. The MCU  418  interprets signals received from the keyboard  412  and the touch sensor as well as controlling the touch sensor  415 . In one embodiment, the MPU  418  passes keyboard pressing data and touch coordinate data directly to the CPU  420  which then performs the switching process  300  of  FIG. 3 . In another embodiment, the MPU  418  performs the switching process  300  of  FIG. 3 , and passes either absolute coordinate data or relative coordinate data along with keyboard pressing data to the CPU  420 . 
     The above illustration provides many different embodiments or embodiments for implementing different features of the invention. Specific embodiments of components and processes are described to help clarify the invention. These are, of course, merely embodiments and are not intended to limit the invention from that described in the claims. 
     Although the invention is illustrated and described herein as embodied in one or more specific examples, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention, as set forth in the following claims.