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1. WO2006095976 - ALPHABET INPUT APPARATUS USING A TOUCHPAD AND METHOD THEREOF

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

[ EN ]

ALPHABET INPUT APPARATUS USING A TOUCHPAD AND
METHOD THEREOF

Technical Field

The present invention relates, in general, to an apparatus for inputting characters using a touch pad and a method of inputting the same and, more particularly, to an apparatus for inputting characters in which a user touches a touch pad that generates five different input signals using a finger in a standardized touch pattern to input English alphabets, Korean alphabets, symbols, numbers and function keys such that the user feels that he or she writes down the characters and a method of inputting the same.

Background Art

Nowadays, with the development of wireless communications, various functions such as functions of transmitting and receiving message characters and of storing telephone numbers and a wireless Internet function as well as a simple audio communication function are included in the functions of a mobile telephone. Also, with the appearance of small apparatuses such as a personal digital assistance (PDA) having a function of editing documents and tables that could be performed in large apparatuses such as a desktop computer, requirement for small apparatuses that can input characters is increasing.

On the other hand, nowadays, smaller portable electronic apparatuses that can be held in one hand such as a small MP3 player are widely used. Since a space for a small key pad that includes 3x4 key buttons for inputting characters does not exist in such a small electronic apparatus, a few control buttons such as an arrow and an input button are commonly used. However, with the development of technology, the capacity of the memory device of the small portable electronic apparatus significantly increases from 16M bytes to IG byte so that a significant amount of MP3 music is stored and that it is annoying to detect desired music by simply arranging navigation key buttons for horizontal and vertical movements.
Therefore, it will be convenient if desired music can be detected by inputting characters to the small MP3 player in which the space for the small key pad that includes the 3x4 key buttons for inputting characters does not exist. Furthermore, it is possible to make the electronic apparatus smaller and to increase a space for display if a smaller and more convenient character input apparatus exists instead of the small key pad in the electronic apparatus such as the mobile telephone or the PDA that adopts the small key pad that includes the 3x4 key buttons for inputting characters.

As described above, requirement for inputting characters increases. However, it is difficult to increase the size of the input apparatus due to the small size of the portable apparatus. Therefore, methods of inputting characters using the conventional 3x4 button-type keypad or another modified device without significantly changing the size of the input apparatus are disclosed.
For example, a technology of inputting characters even by a conventional small key pad that is designed to input only numbers by sequentially inputting the buttons of the key pad in a uniform order in accordance with a standardized pattern, which is a slight modification of the conventional

3x4 button-type key pad, is provided in Korean Patent Laid-open Publication (Korean Patent Application No. 10-2004-0009086 filed on February 11, 2004) by the inventor of the present invention under the title "an apparatus for inputting alphabets using a small key pad and a method of inputting the same". According to the technology, it is possible to easily input characters even by the conventional electronic apparatus such as the mobile telephone or the portable PDA that adopts the small key pad that includes the 3x4 key buttons through a minimal modification. Furthermore, since only five buttons that can be applied to a touch screen are used, it is possible to apply the technology to the electronic apparatus that uses the touch screen or the smaller electronic apparatus that includes only a few buttons for navigation. According to the technology, it is possible to write down English alphabets using only the five buttons that are arranged roughly square to input the English alphabets. However, there are limitations on making a user feel that he or she is writing down the English alphabets considering that the user presses the buttons. Also, since it is possible to input only the English alphabets, it cannot be used when it is necessary to input Korean alphabets and numbers .
On the other hand, an apparatus for inputting characters using a touch pad that replaces the conventional apparatus for inputting characters by arranging key buttons is provided so that numbers and characters can be input to a mobile terminal. For example, a mobile terminal that uses a touch pad in which the touch pad is set in the form of a small key pad that includes 3x4 key buttons to input numbers, stipulated characters, and script stipulated characters in accordance with input modes and to additionally utilize a mouse mode is disclosed in Korean Patent Laid-open Publication (Korean Patent Application No. 10-2001-0067202 filed on October 30, 2001 by the applicant "Mirae Communications Co., Ltd." and the inventor "Cheon Myung-cheol") under the title "a mobile terminal that uses a touch pad" . According to the technology, in a method of inputting characters, in particular, script characters, when the touch pad is pressed in accordance with a stipulated character pattern, a character that corresponds to the stipulated character pattern that is stored in a memory is provided. However, according to the technology, since the character pattern to be pressed on the touch pad is not specified, it is not possible to know whether characters can be actually input and to know which characters are actually input other than numbers. Furthermore, according to the technology, since the size of the touch pad is not expected to be smaller than the size of the conventional 3x4 key pad, it is not possible to use the technology for making the conventional mobile terminal smaller or for inputting characters to a smaller portable electronic apparatus.
Therefore, requirement for a character input apparatus that uses a new touch pad capable of replacing or supplementing the key pad that includes the key buttons in the portable electronic apparatus that adopts the conventional key button character input structure, of making characters input to a so small electronic apparatus that cannot adopt the conventional key button character input structure, of freely inputting English alphabets, symbols, numbers, and Hangeul consonants and vowels, and of increasing recognition speed and recognition ratio while making a user feel that he or she is actually writing down characters still exists .

Disclosure of the Invention

Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a character input technology that uses a touch pad by which it is possible to solve the problems of the above-described conventional character input technology using the touch pad and that has additional advantages .
Another object of the present invention is to provide an apparatus for inputting characters using a new touch pad capable of inputting various characters such as English alphabets, Hangeul consonants and vowels, numbers, symbols, and keys that represent several functions only by five areas using the touch pad that includes the areas that generate five different signals that are arranged square and a method of inputting the same.
Another object of the present invention is to provide an apparatus for inputting characters using a new touch pad capable of inputting numbers, English alphabets, and Korean alphabets using only a smaller touch pad so that it can be applied to a smaller electronic apparatus that cannot adopt the small key pad as well as the electronic apparatus that adopts the conventional key pad that includes the 3x4 key buttons and that it is possible to utilize the function of using characters in electronic apparatuses of various sizes and a method of inputting the same.
Another object of the present invention is to provide an apparatus for inputting characters using a new touch pad by which a user can input desired characters by drawing lines using a finger or a pen-type stylus in accordance with a standardized touch pattern in five areas that are arranged square on the touch pad so that it is possible to make the user feel that he or she is writing down characters and to increase recognition speed and recognition ratio unlike in the conventional writing down type input method.
In order to accomplish the above objects, according to an aspect of the present invention, there is provided an apparatus for inputting characters using a touch pad. The apparatus for inputting characters using a touch pad comprises a touch pad including five character input areas A that generate different signals of a center area A3 and a left-top area A1, a left-bottom area A4, a right-top area A2, and a right-bottom area A5 that are arranged in the vicinity of apexes of a square around the center area A3, means receiving coordinate signals that are generated by a user touching the respective areas of the touch pad to be input, converting the coordinate signals into area input signals, and outputting the area input signals, means sequentially receiving the converted area input signals to generate the received input area input signals as area input signal sequences, storage means storing a character list that includes character sequences that are composed of sequential sequences of an arbitrary area input signal, characters, and function data so that one character or one function data is related to at least one character sequence, and character detection and output means detecting the character list using sequences of the area input signal or a series of area input signals to output a corresponding character whenever one area input signal is received.
According to the present invention, each of the character sequences of the character list is preferably formed of a signal that is generated by continuously touching one or more areas that are arranged in the touch pad in the form similar to a writing form of a related character to be input.
According to the present invention, the character of the character list may comprise at least a part of small letters of English alphabets, capital letters of English alphabets, Hangeul consonants and vowels, numbers, and symbols. In this case, function data that are related to the character sequences preferably comprise at least a mode switching function for switching from one input mode among an English alphabet small letter input mode, an English alphabet capital letter input mode, a number input mode, a symbol input mode, and a Hangeul input mode to another input mode .
According to the present invention, in a pattern where the five areas that generate different signals are arranged, the center area A3 is preferably adjacent to the remaining four areas A1, A2, A4, and A5, the left-top area A1 is preferably adjacent to the left-bottom area A4, the center area A3, and the right-top area A2, the right-top area A2 is preferably adjacent to the left-top area A1, the center area A3, and the right-bottom area A5, the left-bottom area A4 is preferably adjacent to the left-top area A1, the center area A3, and the right-bottom area A5, and the right-bottom area A5 is preferably adjacent to the left-bottom area A4, the center area A3, and the right-top area A2.
According to the present invention, specific marks that make a user visually distinguish the five areas that generate different signals of the touch pad from each other may be printed on the external surface of the touch panel using different materials.
According to the present invention, in a portable electronic apparatus that includes at least a display, the touch pad may be exclusively used for inputting characters in addition to the display. In this case, the character input touch pad preferably has a size of between about 5mmx5mm and about 30mmx30mm and is preferably realized to be proper to inputting characters using a finger of a user or a pen-type stylus.
According to the present invention, in a portable electronic apparatus that includes at least a display and key buttons, the touch pad may overlap at least a part of the key buttons .
According to the present invention, in a portable electronic apparatus that includes at least a display, the touch pad may be a touch screen that includes a transparent hardware touch pad that overlaps the display so that the five areas that are distinguished from each other of the touch pad may be realized as soft touch pad areas on the touch screen. In this case, the soft touch pad areas may be realized to be semi-transparent.
According to another aspect of the present invention, there is provided a method of inputting characters using a touch pad that includes five areas that generate different signals of a center area and a left-top area, a left-bottom area, a right-top area, and a right-bottom area that are arranged around the center area in apexes of a square in order to input characters, the character input method comprising the steps of receiving coordinate signals that are generated by a user touching the respective areas of the touch pad to be input, converting the received coordinate signals into area input signals, and outputting the converted area input signals, sequentially receiving the converted area input signals to generate the received area input signals as area input signal sequences, detecting a character list that includes character sequences that are formed of sequential sequences of an arbitrary area input signal and characters and function data that are related to the at least one character sequences using the area input signal sequences, and when it is determined that a character that corresponds to the area input signal sequences exists, outputting the detected character and receiving the next area input signal to repeatedly detect the character list. Here, each of the character sequences of the character list is formed of a signal that is generated by continuously touching one or more areas that are arranged in the touch pad in the form similar to a writing form of a related character to be input .
According to a preferred embodiment of the present invention, the characters of the character list comprise at least small and capital letters of English alphabet and, when the small and capital letters are input, one of a method a in which character sequences that correspond to the small and capital letters are the same and in which the input of the small or capital letters is determined by whether a character input mode is a small letter input mode or a capital letter input mode, a method b in which character sequences that correspond to the capital letters are additionally determined as repetitions of parts of character sequences of the small letters that are related to the corresponding capital letters, and a method c in which both the methods a and b are adopted may be used.
According to another preferred embodiment of the present invention, the characters of the character list comprise at least Hangeul consonants and vowels and the method may further comprise the step of pressing final areas for a long time and touching the final areas once more after touching characters that correspond to the Hangeul consonants and vowels, that is, character sequences that correspond to the character components to determine that the corresponding character components are completely input.
According to another aspect of the present invention, there is provided a method of inputting characters by detecting a character list that includes character sequences that are formed of a series of area input signals and characters that are related to the character sequences and that is previously stored and by outputting characters in accordance with sequentially input area input signal sequences using a touch pad that includes five areas that generate different signals of a center area and a left-top area, a left-bottom area, a right-top area, and a right-bottom area that are arranged around the center area in apexes of a square in order to input characters, the method comprising a first stand-by step of waiting for an area input signal to be received, a step of adding the received area input signal to generate an area input sequence, a step of detecting the character list using the area input signal sequence, a step of, when it is determined that a character sequence that corresponds to the area input signal sequence exists in the detection step, outputting characters that are related to the character sequence to return to the first stand-by step, a second stand-by step of, when it is determined that a character sequence that corresponds to the area input signal sequence does not exist in the detection step, determining whether a character sequence that includes a sequence that corresponds to the area input signal sequence as a part exists to return to the first stand-by step when the partially including character sequence exists, an erroneous input correction step of, when the partially including character sequence does not exist, determining whether the preliminary character extraction step existed after the detection step when the area input signal was previously received to ignore all of the area input signal sequences that are currently received and to return to the first stand-by step when it is determined that the preliminary character extraction step did not exist, and a definite character extraction step of, when it is determined that the preliminary character extraction step existed, extracting an output character as a definite character to output the extracted character and generating an area input signal sequence that includes only a currently received area input signal to return to the detection step.
According to the present invention, a software program comprising program commands that are realized to perform the steps of the above-described method by a microprocessor and a computer readable recording media in which the software programs are recorded are provided.

Advantageous Effects

As described above, in the apparatus for inputting characters using a touch pad according to the present invention and a method of inputting the same, it is possible to input various characters such as English alphabets, Hangeul consonants and vowels, numbers, symbols, and keys that represent several functions using a touch pad that includes five areas that generate different signals that are arranged square. Furthermore, according to the present invention, since it is possible to input numbers, English alphabets, and Korean alphabets using only a smaller touch pad, the present invention can be applied to a smaller electronic apparatus that cannot adopt the small key pad as well as to the conventional electronic apparatus that adopts the conventional key pad that includes the 3x4 key buttons . Therefore, it is possible to utilize the function of using characters in electronic apparatuses of various sizes. Also, according to the present invention, since a user can input desired characters by drawing lines using a finger or a pen-type stylus in accordance with a standardized touch pattern in five areas that are arranged square on the touch pad, it is possible to make the user feel that he or she is writing down characters and to increase recognition speed and recognition ratio unlike in the conventional writing down type input method.

Brief Description of the Drawings

FIG. 1 is a block diagram that illustrates the structure of a four-line resistance-type touch pad that is a conventional pointing touch pad for the movement of a mouse point of a note book;
FIG. 2 is a block diagram that illustrates the structure of a character input apparatus that uses a touch pad according to an embodiment of the present invention;
FIG. 3 illustrates steps of extracting English alphabets in accordance with an English alphabet input algorithm in a character input apparatus that uses a touch pad according to an embodiment of the present invention;
FIG. 4 schematically illustrates an English alphabet input touch pattern in a character input apparatus that uses a touch pad according to an embodiment of the present invention;
FIG. 5 schematically illustrates a character input touch pattern for inputting symbols or switching an input mode in a character input apparatus that uses a touch pad according to an embodiment of the present invention;
FIG. 6 schematically illustrates a touch pattern for inputting numbers in a character input apparatus that uses a touch pad according to an embodiment of the present invention;
FIG. 7 schematically illustrates a touch pattern for inputting Hangeul consonants in a character input apparatus that uses a touch pad according to an embodiment of the present invention;
FIG. 8 schematically illustrates a touch pattern for inputting Hangeul vowels in a character input apparatus that uses a touch pad according to an embodiment of the present invention;
FIG. 9 schematically illustrates a portable electronic apparatus to which a character input apparatus that uses a touch pad according to an embodiment of the present invention is applied;
FIG. 10 schematically illustrates the size of a character input apparatus that uses a touch pad according to an embodiment of the present invention and a touch method using a finger;
FIG. 11 schematically illustrates a pattern in which five input areas that are distinguished from each other are arranged in the touch pad of a character input apparatus that uses a touch pad according to an embodiment of the present invention;
FIG. 12 schematically illustrates several examples of specific marks on the external surface of the touch pad according to the embodiments of the present invention; and

FIG. 13 schematically illustrates an example in which a character input apparatus that uses a touch pad according to an embodiment of the present invention is applied to a notebook keyboard.

<Description of the elements in the drawings>
A; touch pad A1; left-top area
A2; right-top area A3; center area
A4; left-bottom area A5; right-bottom area
20; character input apparatus 22; touch panel
24; touch panel controller 26; main processor
25; memory 28; display
200; character recognition program
300; look-up table 40; portable MP3 player

42; display 44; touch pad
46; control button 60; PDA
62; display 64; touch panel
66; control button Best Mode for Carrying Out the Invention

Hereinafter, preferred einbodiments of the present invention will be described with reference to the attached drawings. The same reference numerals in the drawings denote similar elements.
In an apparatus for inputting characters according to the present invention and a method of inputting the same, a touch pattern standardized to be similar to a pattern in which a user writes down characters is previously determined so that the user sequentially touches the areas of a character input touch panel that includes five areas in accordance with the touch pattern to easily input desired characters.
Since it is sufficient for the touch panel used in the present invention to provide only five areas that provide different signals as described later, various touch panels, that is, a touch panel to which characters are input by a finger such as a touch panel that is used as auxiliary input means for moving a cursor in a notebook, a touch panel of an improved technology for a touch screen that is used for a terminal of a bank, and a touch panel for a personal digital assistance (PDA) touch screen in which a pen-type stylus is used can be used.
FIG. 1 illustrates a method in which a simple touch panel that can be adopted in the present invention operates. FIG. 1 is a block diagram that schematically illustrates the structure of a conventional four-line resistance-type touch panel apparatus 10. The touch panel apparatus 10 includes a touch panel 12 having lines that can sense four resistances and a touch panel controller 14 that receives analog resistance values from the touch panel 12. The controller 14 includes an analog-to-digital (A/D) converter 142 for converting the received analog resistance values into digital signals, a controller 144 for determining the converted signals as X and Y coordinate values, a local memory 146 in which a reference value for determining the coordinate values and a touch panel driving algorithm are stored, and a communication interface 148 for transmitting the coordinate values to a main processor 16. For example, the main processor 16 that may be a central processing unit (CPU) of an electronic apparatus such as a notebook computer and a PDA is connected to a main memory 15 in which application programs are stored. The main processor 16 controls the movement of a cursor that is displayed on a display 18 using the coordinate values that are received from the controller 14.
FIG. 2 is a block diagram that schematically illustrates the structure of a character input apparatus 20 that uses a touch panel according to the present invention. In the character input apparatus 20, the structures of a touch panel 22, a touch panel controller 24, a main processor 26, a main memory 25, and a display 28 are similar to the structures of the touch panel 12, the touch panel controller 14, the main processor 16, the main memory 15, and the display 18 of the touch panel apparatus 10 that is illustrated in FIG. 1. However, according to the present invention, the signal values from the touch panel 22 are converted into five different area input signals in the controller 24. It is well known to those skilled in the art that the conversion process may be determined by setting the A/D converter in the controller 24 or by setting the touch panel-driving algorithm that is executed by the controller 144.
As illustrated in FIG. 11, the five different area input signals correspond to signals that are generated when a user touches five areas that are distinguished from each other of a touch pad A. The five area input signals on the touch pad A are arranged in the apexes of a square and in the center of the square. For convenience sake, the five areas will be referred to as a left-top area A1, a right-top area A2, a center area A3, a left-bottom area A4, and a right-bottom area A5. The signals that are generated by touching the respective areas will be referred to as A1, A2, A3, A4, and A5 in order to simplify description.
Here, the term 'touch' means 'an act of the user knocking a touch panel or pressing the touch panel to draw a line using an auxiliary tool such as a finger or a pen- type stylus', that is, the same act as the touch act that is performed by common users of the touch panel to move a cursor. Also, the term 'touch' is used to include the meanings of 'clicking' and 'pressing' buttons.
According to the present invention, the user touches the five areas A1, A2, A3, A4, and A5 that are distinguished from each other of the touch panel in a uniform pattern as described later. That is, the areas are continuously touched as if drawing a line using a finger or a stylus in a predetermined uniform order to input characters. When the characters are input, the user touches adjacent regions in order to input one character. Therefore, the character input method according to the present invention has an advantage in that it is possible to input characters in a similar method to the method of writing down characters using a finger such as a thumb.
Referring to FIG. 2, the character input apparatus 20 that uses the touch panel according to an embodiment of the present invention includes the touch pad 22 that includes five areas that are distinguished from each other. The touch pad 22 is connected to the touch panel controller 24 for converting resistance values, pressure values, or supersonic waves strength signals that are generated by touching the touch pad 22 into digital values that are proper to be processed. The controller 24 executes a touch panel-driving program to provide the signals that are generated by touching the touch panel 22 to the main processor 26 as different area input signals. The main processor 26 may be a CPU of a notebook or a main microprocessor in a portable electronic apparatus such as a PDA, a mobile telephone, and an MP3 player according to preferred embodiments of the present invention. A memory 25 and the display 18 are connected to the main processor 26.

A character recognition program 200 and a look-up table 300 according to the preferred embodiments of the present invention are stored in the memory 25. The character recognition program 200 is an algorithm that is executed by the main processor 26 and corresponds seguences that are formed of area input signals that are sequentially input to characters as described later in detail with reference to FIG. 3. The look-up table 300 illustrates a list in which the character sequences that are formed of the area input signals from the touch panel 22 are connected to the characters that correspond to the character sequences, which will be described in detail with reference to FIGs. 4 to 8 and Tables 1 to 10. The display 28 displays the characters that are recognized by the main processor 26 to the user whenever the touch panel 22 is touched. In the drawings, the touch panel 22 and the display 28 are separated from each other. However, it is apparent to those skilled in the art that a touch screen in which the transparent touch panel 22 overlaps the display 28 belongs to the scope of the present invention.
A few application examples of the character input apparatus that uses the touch panel according to the present invention of the above structure are illustrated in FIGs. 9 and 13. FIG. 9A illustrates an example of a design that can be applied to a small MP3 player 40. A display 42 and a touch panel 44 are provided on the front surface of the MP3 player 40 and a control button 46 such as an on/off power switch button is provided on the side surface of the MP3 player. According to the present example, navigation such as the movement of a cursor and character input according to the present invention can be performed by the touch panel 44. FIG. 9B illustrates an example of a design that can be applied to a PDA 60. According to the present embodiment, a touch panel 64 overlaps a navigation arrow button 66 to be provided under the navigation arrow button 66. When the user navigates a menu, the touch panel 64 may be deactivated. When the user inputs characters, the touch panel 64 for inputting characters is activated and the navigation arrow button 66 may be deactivated. FIG. 13 illustrates an example of a keyboard 70 of a notebook computer. According to the present example, a character input touch panel A according to the present invention is added to a common keyboard 72 and a touch panel 74 for moving a cursor. The above examples are some of various application examples of the character input apparatus that uses the touch panel according to the present invention and it is apparent that those skilled in the art can easily conceive other various application examples .
Although not shown, the touch pad according to the present invention is a touch screen that includes a transparent hardware touch pad that overlaps a display in a portable electronic apparatus that includes a display. At this time, the five areas that are distinguished from each other of the touch can be realized as a soft touch pad areas that are provided on the touch screen. In this case, the soft touch pad areas are preferably realized to be semi-transparent .
In the character input apparatus that uses the touch pad according to the present invention, in particular, the size of the character input touch pad may be significantly reduced. In this case, the size of the touch pad may be between about 5mmx5mm and about 30mmx30mm and is preferably about 15mmxl5mm. Such a size is proper for the user to input characters using a finger. Such a specific size is proper as the size of the touch panel according to the preferred embodiment of the present invention for a small electronic apparatus. However, the present invention is not limited to the size. For example, a large touch pad of about 50mmx50mm can be made.
On the other hand, the touch panel according to the present invention is preferably square. However, it is apparent to those skilled in the art that it is not necessary to use only the square touch panel for the present invention but that a touch panel of any form in which five areas that are distinguished from each other are arranged roughly square be used for the present invention.

In particular, a preferred characteristic of a small touch panel is schematically illustrated in FIG. 10. FIG. 1OA illustrates that a user puts his or her thumb in the center of the touch panel 44 mounted in the MP3 player 40 and FIG. 1OB illustrates that the user puts his or her finger at the edge of the touch panel 44. A preferred relative size between the touch panel and the finger is illustrated in the drawing. Also, according to the present invention, a smaller touch panel may be used. In this case, not a finger but an auxiliary tool such as a pen-type stylus that is commonly used in a conventional PDA is used to input characters.
As illustrated in FIG. 12, according to the present invention, specific marks by which a user visually distinguishes the five areas that generate the different signals of the touch pad may be printed on the external surface of the touch pad using different materials to protrude or recede from boundaries among the areas. FIG. 12 illustrates nine examples of the marks. However, the present invention is not limited to the above examples but various modifications may be conceived by those skilled in the art. Also, a case in which there are no marks on the touch panel belongs to the scope of the present invention. As another example, five buttons may be displayed on the touch panel. Also, marks in the form of various stickers may be provided so that the user selects a desired mark to be used.
In the character input apparatus according to the present invention, the user can input characters using the touch panel in which specific marks exist or no marks exist as if he or she writes down the characters on paper. In this case, signal values are generated in the five input areas that are distinguished from each other of the touch panel as analog values to be converted into one or more discrete values or to be generated as a plurality of discrete values. Such an input method will often be referred to as a 'graffiti' method hereinafter since characters are input by drawing lines. In another method, the user may touch the respective areas by pressing buttons using a touch panel on which five buttons are displayed. In this case, the signal values that are generated in the five areas that are distinguished from each other of the touch panel may not be in an analog method and it is enough that only one signal is generated. The method of inputting characters by pressing the buttons will often be referred to as 'a button pressing input method' hereinafter.
Referring to FIGs. 2 and 3, the area input signals that are generated by touching the touch pad 22 are processed by the character recognition program 200 that is executed by the main processor 26, are extracted as the corresponding characters through the steps illustrated in FIG. 3 in which English alphabets are illustrated as an example, and are displayed on the display 28. In the process of extracting the characters, a character list in which the character sequences that are formed of the predetermined area input signals are connected to the characters that correspond to the character sequences as described in detail with reference to FIGs 4 to 8 and Tables 1 to 10 is detected. The character list may be realized as the look-up table 300 that is stored in the memory 25 that is connected to the main processor 26 to be inquired. According to the present invention, detection of the character list is preferably performed by a control device whenever one area is pressed as described in detail hereinafter.
As noted from FIGs. 4 to 8, in the character input method according to the present invention, in order to input arbitrary characters among English alphabets, symbols, function keys, numbers, and Hangeul consonants and vowels, the areas that are arranged to be similar to the written form of the corresponding character are pressed. For example, as illustrated in FIG. 4 and Table 1, in order to input a character 'a' , a user sequentially presses the areas A4, A3, and A5 among the five areas A1, A2, A3, A4, and A5 (refer to FIG. 11) . In this case, as illustrated in the drawings, since the areas to be presses are arranged to be adjacent in the form that is similar to 'a' , the user presses or 'touches' the corresponding areas as if drawing a line by a finger.
According to a specific embodiment, when a small letter and a capital letter of an English alphabet are input, the input sequence pattern of the capital letter 'A' may be the same as the input sequence pattern of the small letter 'a' . According to an embodiment of the present invention, with respect to the same area input pattern, a small letter is output in a small letter input mode and a capital letter is output in a capital letter input mode. At this time, a 'Caps Lock' function key sequence for switching to a capital letter input mode or for switching to a capital letter/a small letter in a toggle method a 'Shift' function key sequence may be designated. The function key sequences are illustrated in Table 3 and FIG. 5. For example, the sequence for the 'Shift' function key is Al and A4 and only one character input can be input as a capital letter after the sequence. On the other hand, the sequence for the 'Caps Lock' function key is A1, A4, A1, and A4, which is a repetition of the 'Shift' function key. In this case, switching to the capital letter input mode can be performed.

In another method, the input sequence pattern of the capital letter 'A' may be different from the input sequence pattern of the small letter 'a' , however, is preferably a pattern obtained by adding a simple rule, for example, a pattern that is similar to the small letter input pattern such that a part of the small letter input pattern is repeated in order to prevent the user from being confused. Such an example of the capital letter input pattern is illustrated in Table 2. As illustrated in the Table 2, meanwhile the input pattern of the small letter 'a' is A4, A3, and A5, the input pattern of the capital letter 'A' is A4, A3, A5, and A3. The capital letter rule according to the present example is to repeatedly touching the immediately previous area of the final input area signal . According to such a method, the user adds a simple repetition rule to the small letter input method to easily input the capital letter.
As illustrated in FIG. 4, the number of area input sequences that are related to 'A' or 'a' may be four and the number of area input sequences related to 'B' or 'b' may be two. One or more input sequence patterns may be related to each of other English alphabets, sentence marks, numbers, Hangeul consonants and vowels as illustrated in FIGs. 4 to 8 and Tables 1 to 10. The examples illustrated in FIGs. 4 to 8 and the Tables 1 to 10 are some of various examples that may exist and various combinations can be alternatively and/or additionally performed.
In the following tables that are given as examples, A1, A2, A3, A4, and A5 refer to a left-top area, a right-top area, a center area, a left-bottom area, and a right-bottom area and are illustrated in FIG. 11.
The rule of the touch patterns for inputting characters according to the present invention that are illustrated in the following tables and FIGs. 4 to 8 is Continuity' . That is, in the character extraction through the touch patterns according to the present invention, a character is extracted using continuous input area signals from the area in which the user starts to touch the touch panel to the area in which the user terminates touching the touch panel . The user must write down a character without taking his or her finger (or stylus) off the touch panel from the touch start area to the touch termination area. This rule is applied to all of the touch patterns for inputting characters excluding 'k' and 'K' .
According to the present invention, touch patterns can be made only if the rule that the five areas are continuously touched is satisfied. However, additional rules that limit the above rule on start and termination may be further provided.
Additional Rule 1 [Limitation on the Termination Area of a Touch Pattern] The termination points of all of the touch orbits (here, an 'orbit' an abstract line that connects the touched areas to each other) excluding the touch orbits whose resultant values are closed areas do not terminate in the left-top area A1. For example, when the user desires to input the alphabet 'D' , a touch pattern in which the user touches the areas in the order of A1-A3-A4 is available, however, a touch pattern in which the user touches the areas in the order of A4-A3-A1 is not available. As described above, the touch pattern in which the termination area is A1 is processed as an error. However, the above is not true of touch patterns for symbols or function keys . The function keys include a function key for switching to a capital letter and a small letter such as 'Caps Lock' and a function key for deleting previously input characters such as 'back space' and the symbols are commonly used together with characters such as '?' .
Additional Rule 2 [Limitation on the Start Area of a Touch Pattern] The orbit by which the user continuously touches the areas does not start from the right-bottom area, that is, A5. For example, 'A4-A3-A5' is available as a touch pattern for inputting the alphabet 'a' , however, a touch pattern such as 'A5-A3-A4' is not available.
The additional rules are aimed at making the touch patterns of the graffiti input method the same as the touch patterns of the button pressing input method. The button pressing input method is different from the 'continuous' graffiti input method in that five button pressing input signals are included in the button pressing input method and that only intermittent button pressing acts exist without 'continuous writing acts' in the button pressing input method. When the additional rules are applied to the graffiti input method, it is possible to make the touch patterns of the button pressing input method as the touch patterns of the graffiti input method. However, reverse input may be performed without limitations of the additional rules on the start and termination in the touch patterns of the graffiti input method according to a preferred embodiment of the present invention.
In the touch patterns of the button pressing input method of Hangeul of Tables 7 and 8, when the final input area signals that are thickly underlined are pressed for a long time, it means that the corresponding character sequences are completed. In the touch patterns of the button pressing input method of Hangeul of Tables 9 and 10, the input area signals that are thickly underlined and that are repeated mean that the corresponding character sequences are completed to be distinguished from the preceding input characters . In accordance with the number of times of repetitions, phonetic values are switched in the order of voiceless consonants-aspirations-fortes in the case of the consonants and in the order of single vowels-diphthongs in the case of the vowels.

[TABLE 1]
Graffiti input patterns of English small letters
(or English capital letters)


[TABLE 2 ]
Graffiti input patterns of English Capital letters


[TABLE 3 ]
Graffiti input patterns of symbols and function keys


[TABLE 4]
Graffiti input patterns of numbers


[TABLE 5 ]
Graffiti input patterns of Hangeul consonants


[TABLE 6]
Graffiti input patterns of Hangeul vowels


[TABLE 7 ]
Button pressing input patterns of Hangeul consonants


[TABLE 8]
Button pressing input patterns of Hangeul vowels

[TABLE 9]
Button pressing input patterns 2 of Hangeul consonants


[TABLE 10]
Button pressing input patterns 2 of Hangeul vowels


The above-described character extracting process 200 will be described in detail with reference to FIG. 3. In the drawing, the process of extracting English alphabets is illustrated. However, it is apparent to those skilled in the art that the process is also applied to symbols, numbers, and Hangeul consonants and vowels.
According to the present invention, when the user knocks the areas that are distinguished from each other on the touch panel A or presses the areas to draw a line, the signal that is generated by the touch panel in accordance with the act is input to the character extracting process 200 that is performed by the character recognition program that is executed by the main processor that is the control device as the area input signal. The character extracting process 200 includes a first stand-by step 220 of standing by an area input signal, a step 235 of generating an area input sequence, a step 245 of detecting a character list, preliminary character extraction steps 255 and 256 of outputting a character to return to the first stand-by step, a second stand-by step 265 of returning to the first stand-by step without preliminary character extraction, a first erroneous input correction step 275 of ignoring all of the area input signal sequences that are currently received, and a definite character extraction step 285 of extracting a character to return to the detection step.
First, when the user presses the center area for no less than a predetermined time, an English alphabet small letter input mode according to the present invention can start (step 210) . In an initialization step 215, a count I is initialized to a null 0 value and a character value m that represents a character and an area input signal sequence I are initialized to the null 0 value.
In the first stand-by step 220, the control device waits for the next area input signal to be received. When the next signal is received, the count i increases by one and the area input signal currently received is added to a previously input signal (when the signal exists) to generate the area input signal sequence I (step 235) . The area input signal sequence I that is generated in the generation step 235 is compared with the character sequences that are included in the character list so that related characters are detected accordingly.
On the other hand, it is determined whether the area signal is a reset area, an area to be switched to another function, or an area (key) for switching to an input mode of another language/canceling before the generation step 235 (step 225) . In a case of the reset area (for example, when the left-top area is pressed for a predetermined time for a long time) , the step is returned to the initialization step 215 and, in a case of another function key, the character extraction step is stopped to resume the corresponding function (step 230) .

When the area input signal sequence I is generated, the character list is detected using the generated area input signal sequence I. In this step, it is determined whether the character sequence that corresponds to the area input signal sequence I exists in the character list (step 245) .
In the step of detecting the character list, it is determined whether the character sequence that corresponds to the area input signal sequence I and the character that is related to the area input signal sequence I exist (step 250) . When it is determined that the character sequence that corresponds to the area input signal sequence I and the character that is related to the area input signal sequence I exist, the related character mi is output as a preliminary character extraction step (step 255), the character m' is added to the character value m (step 256) , and the step is returned to the first stand-by step 220. For example, when the currently touched area is A4, however, when the A4 area signal is added to the A1 area signal that is the previous signal to generate an area input signal sequence {A1, A4 }, since the character sequence that is related to the character 'i' exists, the character 'i' is output. Since the character that is extracted in this step may not be definite, this step is a preliminary character extraction step. In order to definitely extract the character, the preliminary character extraction step must be performed.
In the detection step, when it is determined that the character sequence that corresponds to the area input signal sequence does not exist, (NO of step 250) , it is determined whether a character sequence that includes the sequence that corresponds to the area input signal sequence as a part exists (step 260) . When the partially including character sequence exists (YES) , the step as the second stand-by step returns to the first stand-by step without any output (step 265) . When the user first touches the A4 area after initialization, the character that corresponds to the area input signal sequence {A4 } does not exist with reference to the Table 1. However, a plurality of characters such as a, m, o, and p exist as characters that partially include the area input signal sequence {A4}. In this case, since one character cannot be determined, no character is displayed in the current step to wait for the next area to be input.
When the partially including character sequence does not exist (NO) , it is determined whether the preliminary character extraction step existed after the detection step when the area input signal was previous received (step 270) . When the preliminary character extraction step did not exist (mi-1 does not exist) , the step proceeds to the erroneous input correction step. In the erroneous input correction step, all of the area input signal sequences that are currently received are ignored and the process returns to the first stand-by step. At this time, a warning sound (beep) that informs erroneous input may be output

(step 275) . For example, when the user touches the A5 area to generate an area input signal sequence {A5}, since no character that is related to the character sequence {A5}

(even partially) is found in the Table 1, all of the area input signals (the right-bottom area according to the present example) that are currently input are ignored and the process returns to the step of waiting for the next area to be input with the output of the beep. According to the erroneous input correction step, the erroneously input area sequence is automatically deleted. Therefore, the user can resume inputting areas for desired characters without additional manipulating areas for deletion.
In the step 270, when the preliminary character extraction step existed (mi-1 exists) , the output character is extracted as a definite character to be output (step 285) . At the same time, an area input signal sequence that includes only the currently received area input signal is generated again (step 290) to return to the detection step. This step is a definite character extraction step. A character will be made definite only by this step. For example, when the user inputs the A1 area to generate an area input signal sequence {A2, A5, A1}, no character that is related to the character sequence {A2, A5, A1} is found in the Table 1. However, the character 'i' was preliminarily extracted by {A2, A5} in the previous step. Therefore, the character 'i' that was preliminarily extracted in the previous step is output as a definite character in the current step. At the same time, an area input signal sequence that includes only the currently received area input signal is generated. According to the present example, the process returns to the step of detecting the character list again using the sequence that is composed of {A1}.
The main processor extracts a character through the above steps to display the extracted character on the display so that the character can be input. Since the respective steps are rapidly processed, the user only has to draw a desired character on the touch pad.
According to the present invention, the respective steps of realizing the above-described methods can be performed by logically processing the input area signals and by detecting the previously stored list. Therefore, the methods can be realized by program commands that can be executed by a microprocessor. Therefore, according to the present invention, there is provided computer readable recording media in which software programs for realizing the methods are recorded.
While this invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.