Method and Apparatus To Input Text On Devices Requiring A Small Keypad

#Mobile personal devices, like handhelds or cell phones are providing people with more and more convenience, as more and more they are light in weight, small in size, flexible in manipulation and powerful in functionality. Yet there lies a big difficulty or bottleneck toward making it ultimately convenient: inputting data, or inputting text. The prevailing way nowadays to input data into electronic devices are using keyboard/mouse, but by its nature, a mobile device can only be attached with relatively small inputting elements.

#Existing design and inventions to address this problem fall into two categories: using a keyboard or using a keypad. The former includes reducing the size of the keyboard or make it transferable—e.g. foldable—to make it mobile. But essentially a keyboard with all the keys on can not achieve the same mobility cell phones possessing.

#To instead use a keypad with limited number of keys on, each key must carry multiple characters, followed that there must be a method to resolve the ambiguity, i.e. to determine which one is entered at the time a key is pressed. There are prior arts as following:

#FIG. 1 is a front view of a cellular phone with two shift keys on the side as an embodiment of the invention. With two such keys, plus actuated together forming a third one, 10 regular keys can generate 40 character outputs equally by the time of one press, which is enough to cover 10 numbers and 26 letters;

#FIG. 2 illustrates the embodiment of the invention mentioned in FIG. 1 being held in a human hand. The middle and the third finger naturally rest on the two shift keys, enabling users to operate conveniently and comfortably.

#FIG. 3 is a back view of a cellular phone with the surface concaved to allocate a shift key on the bottom. Instead of having a flat surface thus shift-key press happens in the direction of back to front, this design allows it to be in the top-down direction without causing movements of the phone body. The concaved part is preferred to be home position of the forefinger.

#By studying on cell phones and similar devices, it could be observed that at least three fingers are always required in the device operation. Normally a thumb presses buttons, and the middle and the third finger together with the palm play the role of holding the device. In the case of using the right hand, the middle and the third finger are placed on the left side and the palm on the right. The little finger is usually placed under the device to provide extra support, although that may not always be necessary.

#For devices even smaller, often only the middle finger is placed on the left side. But in this case the forefinger is there to form another strong support, consequently there are still three fingers in participation.

#As it can be seen, two fingers in the operation now only have limited usages of holding and supporting. The thumb is the only one doing the actual inputting. If all fingers participate key-pressing the task could be made easier. This is possible as the fingertips still have the flexibility and freedom to press a button as other part of the finger holding the device. If two special buttons placed on the position where they can naturally access, the original issues may be solved. This leads to the idea of Shift keys there, which functions similar to such keys on a regular keyboard. Unlike on a keyboard where one key is shared at most by two characters, more Shift keys are necessary for a keypad on which one key is typically shared by four characters.