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Publication Date: 2003-Dec-03
Document File: 8 page(s) / 2M

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Shawn Day: INVENTOR [+3]


Character recognition and registration with capacitive touch-sensor devices.

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Inventors: Shawn Day, Sarangan Narasimhan, and Joseph (Kurth) Reynolds

Synaptics Incorporated, San Jose, CA, USA

Field of Invention: Character recognition and registration with capacitive touch-sensor devices.

1.    Part I: Alternative Forms of Mobile Text Input Using 2D Touch Sensors

Figure 1: Nokia 6600

2.    Short Summary

A 2D touch sensor known as FlexPad has been envisioned as a text entry device for mobile phones. FlexPad would be mounted under a mobile phone keypad, allowing handwriting input using a finger sliding over the keypad. The present invention uses similar or identical hardware, but replaces the handwriting recognition with an on-screen keyboard along with alternative forms of selection.

3.    General Description

A 2D touch sensor would be embedded under the keypad of a mobile phone, such as the Nokia 6600 phone shown in Figure 1. The display would present an on-screen keyboard, similar to that employed for Spiral text input using a stylus.

When the user places a finger or thumb (referred to later as the “pointing finger”) on the keypad, a cursor appears on the screen in a corresponding location. Thus, there is a simple one-to-one mapping between the touch sensitive keypad and the display screen area. This one-to-one mapping allows the user to rapidly position the cursor anywhere on the display.

Moving the pointing finger over the keypad causes the cursor to move on the display. When the cursor is over one of the displayed keys on the on-screen keyboard, that key can be highlighted to provide feedback to the user. To enter a character corresponding to the highlighted key, the user simply presses down on the key that happens to be beneath the pointing finger. Thus, it is important for the keypad not to have significant inactive gaps between keys so that the pointing finger doesn’t need to be moved in order to press a key.

4.    Some Problems Solved

The present invention enables one-handed text input on mobile phones in a less awkward manner than handwriting recognition. In particular, while one-handed input for both approaches requires primary use of the thumb, the present invention requires significantly less thumb dexterity than handwriting recognition.

In addition, the present invention is a deterministic method for text input, meaning that a user should be able to enter any desired character reliably. Handwriting recognition, on the other hand, can be probabilistic due to different writing styles and ambiguity in character forms.

5.    Some Additional Advantages

Unlike handwriting recognition, the present invention is likely to require little or no training of the end user. When the mobile phone is in text input mode, the on-screen keyboard can be made to appear automatically, giving a visual indication that text input is expected. Even if the user doesn’t know how to proceed, he will eventually place a finger on the keypad, causing the cursor to suddenly...