Automatic spelling correction apparatus

This patent application is a continuation application (CA) of a U.S. patent application Ser. No. 10/817,804 filed Apr. 6, 2004, and now pending. The contents of the related patent application are incorporated herein for reference.

The present invention relates to input correction, and more particularly to an apparatus for automatic spelling correction.

Handheld devices, such as cellular phones, and PDAs, are designed to be small enough to meet mobility requirements. In order to reduce size handheld devices provide a limited number of buttons for input, and the sum of the buttons is less the total number of characters, such as English letters or phonetic symbols corresponding with Zhu Yin Fu Hao phonetic symbol system. Mobile phones, for example, are limited to 12 buttons for input of phonetic symbols to assemble a Chinese word while the Zhu Yin Fu Hao phonetic symbol system has 37 phonetic symbols, resulting in input difficulty. Hence, cycled buttons, capable of inputting character combinations with one key have been introduced for use in handheld devices. The cycled button enables to input a series of character elements by continuous key pressing. Cycled buttons are discussed in further detail in the following.

FIG. 1 is a schematic diagram of a conventional key pad of mobile phone. Buttons 10 to 19 are utilized to input Arabic numerals, phonetic symbols, English letters, or other characters associated with a particular input mode. In Zhu Yin Fu Hao input mode, the phonetic symbol is input by pressing button 11, and is subsequently, replaced with and in sequence when button 11 is pressed continuously. In addition, is appended to to generate the phonetic symbol combination since is input when button 19 is pressed. Similarly, cycled button input is also applicable to English entries. The letter “A” is input by pressing button 12. “A” is replaced sequentially by “B” and then “C” when button 12 is pressed continuously. Further, after the letter “A” is input, the letter “W” is appended to “A” by pressing button 19 to generate the character combination “AW”.

Although character entry via cycled button is functional, requiring additional keystrokes to input a phonetic symbol or an English letter may be considered by some to be inconvenient or even difficult. For example, the phonetic symbol combination requires only 3 keystrokes, it requires a total of 6 keystrokes using the cycled buttons described above.

It has often been argued manipulating cycled buttons is difficult due to small, difficult to read prompts. Additionally, when an incorrect character is input, the “clear” button must be pressed to first erase the character before the correct character can be input, resulting in additional keystrokes. For example, when the intended input is but is entered instead, the clear button must first be pressed to erase and button 18 must then be pressed to append to

Moreover, a series of not only characters but character combinations are generated by continuously pressing cycled buttons. Not all character combinations, however, have valid spelling. For example, and are sequentially generated by pressing the button 18 after is input, but is an invalid spelling. Hence, it is desirable to provide a means of automatically disregarding the invalid spelling, thereby eliminating unnecessary additional keystrokes.

In view of these limitations, a need exists for a method and an apparatus of automatic spelling correction to effectively reduce keystrokes.

It is therefore an object of the present invention to provide an automatic spelling correction apparatus to reduce keystrokes.

According to the invention, the apparatus comprises a storage device, a processing unit, and a display unit. The sum of cycled buttons of the apparatus is less than the sum of the characters. Each cycled button with a keystroke number corresponds to a unique character.

The storage device stores a character group table and multiple character combination records. The character group table stores a character sequence associated with each cycled button. The character combination records store multiple character combinations indicating the partial or complete valid spelling.

After inputting an original character combination and a first character, the processing unit first determines whether a first character combination consisting of the original character combination and the first character is valid spelling according to the character combination records.

In one embodiment, if the first character combination is invalid spelling, a second character combination is automatically generated by appending a second character to the original character combination. The first character and the second character are associated with the same cycled button.

In one embodiment, if the first character combination is invalid spelling, a third character combination is generated by replacing the last character of the original character combination with the first character combination.

In one embodiment, if the first character combination is invalid spelling, a fourth character combination is generated by replacing the first character of the first character combination with a third character without activating a clear button.

In one embodiment, the apparatus is a handheld communication device and the characters are Zhu Yin Fu Hao phonetic symbols to be converted into Chinese words.