The present invention relates to a character input device provided in a mobile phone, a PDA, a notebook computer, a car navigation apparatus, or the like, and to a method of processing a character string input through the character input device.
Recently, with the rapid development of electronic equipment-related technology, portable terminals, which provide various functions, continue to appear. The size of terminals, which is a principle factor to consider for portability, trends toward reduction in connection with the evolution of related technology and consumers' demand. At the present time, it is no exaggeration to say that the key point governing reduction in size resides in the structure of a character input device provided in a terminal.
A keyboard that is reduced in size (reduced at a specific ratio) and has a ‘QWERTY’ arrangement is taken as an example of a conventional character input device for a terminal. This keyboard is constructed by reducing a keyboard, which is generally and widely used as a character input device for a computer and has a ‘Sholes’ arrangement, to a size suitable for the size of a mobile terminal. As the overall size is reduced at a specific ratio, a user commonly takes a method of inputting a specific character string by pressing key buttons using the thumb while holding both sides of the terminal with two hands. Since a keyboard having the above-described structure employs the arrangement of a computer keyboard as it is, it is advantageous in that it is not necessary to learn a new character layout. However, since the locations of key buttons reduced in size as described above are checked using the eyes and are pressed using the thumb, there are problems in that the rapid input of characters cannot be expected and use while moving is inconvenient.
For reference, the keyboard of a computer, in other words, a keyboard having a ‘Sholes’ arrangement, shown in
Meanwhile, another example of the conventional character input device for a mobile terminal is a character input scheme using the numeric keypad of a wired/wireless telephone, which is illustrated in
First, there is a method in which a user definitely designates the character to be input. For example, this method is a method in which character ‘A’ is input when key ‘2’, to which characters ‘A’, ‘B’ and ‘C’ have been assigned, is pressed once, character ‘B’ is input when the key ‘2’ is pressed twice, and character ‘C’ is input when the key ‘2’ is pressed three times. This method is disadvantageous in that the character input speed is lowered considerably because the same key must be pressed many times, and furthermore, a subsequent character must be input after a cursor has been moved to the input location of a subsequent character by pressing a predetermined direction key or after waiting until a predetermined time period has elapsed, in the case where characters assigned to the same key (for example, ‘J’, ‘K’ or ‘L’, assigned to key ‘5’) must be successively input.
Second, there is a method in which an input character is determined by a system itself, other than a user, in the case where a key to which a plurality of characters has been assigned is pressed. A user inputs a character string by pressing each key once regardless of which of the characters assigned to the corresponding key is input. In this case, since a plurality of characters has been assigned to a single button, a plurality of combination character strings is formed. For example, when the character string desired to be input is ‘PAT’, keys ‘7’, ‘2’ and ‘8’ are pressed. Since the keys are respectively assigned ‘P’, ‘R’ and ‘S’, ‘A’, ‘B’ and ‘C’, and ‘T’, ‘U’ and ‘V’, a total of 27 combination character strings can be formed. Each of the combination character strings is compared with the words in the word database stored in the system, only significant combination character strings corresponding to words are left and the other character strings are discarded, and a user is allowed to finally select one in the case where a plurality of combination character strings remains.
This method has improved character input speed, compared to the above-described first method, because a user presses a key, to which a character is assigned, once so as to input the corresponding character, but this method does not provide sufficiently fast input speed, compared to a computer keyboard (a keyboard having a ‘Sholes’ arrangement), because the numeric keypad structure of a telephone is still used, and therefore a user must input characters using the thumb or index finger. Furthermore, since it is difficult for a user to achieve complete mastery of the arrangement of characters assigned to keys, and since characters can be input using only one or more fingers, even if the user achieves complete mastery of the arrangement, the user must always observe the keys while inputting characters. As a result, this method also has poor utility in a mobile environment, like the first method.
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 device for a terminal and a method of processing a character string, which allow the size of the character input device to be sufficiently reduced so as to improve the portability of the terminal, enable rapid and accurate character input in a touch typing fashion even in a mobile environment, and can minimize the number of presses of each key for the input of each character.
Furthermore, another object of the present invention is to provide a character input device for a terminal, which employs a character arrangement having a mirror-image vertical symmetry based on a ‘Sholes’ character arrangement, therefore a user can easily grasp the usage method thereof.
In order to accomplish the above objects, the present invention provides a character input device for a terminal, including a plurality of character keys and a function key, wherein the character keys include a character arrangement corresponding a first half of a ‘Sholes’ character arrangement with respect to a center of the ‘Sholes’ character arrangement, a character arrangement of a second half of the ‘Sholes’ character arrangement being arranged on the character keys at locations mirror-image symmetrical to the first half with respect to the center of the ‘Sholes’ character arrangement.
Preferably, an input character string may be processed through step S100 of adding characters, arranged on respective pressed keys, to a character string buffer when an English key sequence is input through the character input device; step S200 of generating combination character strings from the characters added to the character string buffer; step S300 of searching the word database for words matching corresponding combination character strings on an assumption that each of the generated combination character strings is a word having a prefix/stem/suffix combination, and generating a recommended word list using the matching corresponding combination character strings; and step S400 of displaying the generated recommended word list on a display device of the terminal.
Meanwhile, an input character string may be processed through step S10 of adding characters, arranged on respective pressed keys, to a character string buffer when a Korean key sequence is input through the character input device; step S20 of generating a combination character string tree from the characters added to the character string buffer; step S30 of examining whether combination character strings of the combination character string tree comply with a rule of vowel and consonant combination; step S70, if the combination character string does not comply with the rule of vowel and consonant combination, deleting a part of a tree below the combination character string, backtracking to a location of a most recent meaningful character string, selecting a subsequent combination character string, and then returning to the step S30; step S40 of, if the combination character string complies with the rule of vowel and consonant combination, searching the word database for a word that matches the assumed word on an assumption that the corresponding combination character string is a word having a prefix/stem/suffix combination; step S50 of determining whether there is a matching word at the step S40; step S60, if, as a result of the determination at step S50, there is a matching word, adding the corresponding character string to the recommended word list, and displaying the combination character string on a display device of the mobile terminal; and the step of, if, as a result of the determination at the step S50, there is no matching word, returning to the step S70.
a is a view illustrating an example of a right hand-dedicated English character input device according to the present invention;
b is a view illustrating an example of the relationship between the conventional keyboard having a ‘Sholes’ arrangement and the character input device of
a is a view illustrating an example of a right hand-dedicated combination character input device according to the present invention;
b is a view illustrating an example of a left hand-dedicated combination character input device according to the present invention;
a is a detailed flowchart illustrating step S300 of
b to 11g are detailed flowcharts illustrating respective steps of
800: mobile terminal according to the present invention
810A: first character input device
810B: second character input device
820: memory
822: control program
824: word database
830: control module
The features and advantages of the present invention will be more apparent from the following detailed description based on the accompanying drawings. First, the terms and words used in the present specification and claims must be interpreted to comply with the technical spirit of the present invention based on the principle in which an inventor can define the concepts of terms in order to describe his or her invention in the best way. Furthermore, it should be noted that detailed descriptions are omitted below if it is determined that the detailed descriptions of well-known functions and constructions related to the present invention may make the gist of the present invention unclear.
When a character input device is applied to the above-described mobile terminal, most of attempts to disregard and completely change a well-known character arrangement may be ignored by users no matter how effective the mobile terminal is. The reason for this is that there are very few people who abandon a conventional character arrangement, to which they have been accustomed for a long time, and accept a new arrangement. Accordingly, the present invention uses the ‘Sholes’ character arrangement familiar to users, with the above fact being taken into consideration.
Hereinafter, a character input device for a terminal according to an embodiment of the present invention, to which a ‘Sholes’ character arrangement is applied, is described below. As illustrated in
Each key of the character key part 310 is assigned a pair of characters that are placed at locations having a mirror-image symmetry relationship with respect to the center of a typical ‘Sholes’ keyboard, as illustrated in
In more detail, characters assigned to the corresponding fingers of both hands (for example, the index fingers of the right and left hands) in the conventional ‘Sholes’ keyboard are arranged on the keys 310a and 310b that correspond to the location of the same finger of one hand (in the present embodiment, the right hand), therefore both hands have a mirror-image symmetrical relationship. The reason for this is to enable touch typing to be performed using only the right hand, as in the embodiment of the present invention. Of course, in order to type characters, assigned to the left hand in the conventional keyboard, using only the right hand, some trial and error is required. However, considering that conventional touch typists (users accustomed to the conventional character arrangement) memorize the character arrangement (‘QWERTY’ arrangement) using the muscle memory of both fingers rather than their brains, the trial and error may be sufficiently reduced. In other words, the above-described character input device 300 of
The above-described character input device 300 relates to a right hand-dedicated English character input device, and enables a user to perform touch typing using the right hand while holding a terminal, which employs the character input device 300, using the left hand. In a similar way, a left hand-dedicated English character input device 400 that enables a user to perform touch typing using the left hand while holding a terminal using the right hand, which is shown in
Although character input devices 300 and 400 for English have been discussed, the same scheme may be applied to the Korean alphabet. In the present embodiment, a Hangeul 2-set standard keyboard layout corresponding to the ‘Sholes’ character arrangement is a basis. A right hand-dedicated Korean character input device 500 and a left hand-dedicated Korean character input device 600 may be constructed, as shown in
Furthermore, a character input device including the above-described English characters, Korean characters, and numerals 0˜9 may be considered. Preferably, switching between English character, Korean character and numeral input modes may be easily achieved using a specific switching key that may be added to the character input device as a function key. Moreover, switching between the right hand-dedicated input device and the left hand-dedicated character input device may be easily achieved through the control program of a terminal. A character input device composed of a combination of English characters, Korean characters and numerals (hereinafter referred to as a ‘combined character input device’) is as illustrated in
A character input device according to the present invention and a terminal using a terminal character input device are described in detail below with reference to
Here, the mobile terminal 800 further includes a detachable second character input device 810B, in which case the two character input devices 810A and 810B may be respectively set to a left hand-dedicated character input device and a right hand-dedicated character input device, and may be used as a full-sized ‘QWERTY’ keyboard. In the case where the two character input devices 810A and 810B are used, the mobile terminal 800 will be useful for vehicle terminals (navigation devices or computers) and general computers. In the case where the mobile terminal 800 is applied to a vehicle terminal, character input devices 810A and 810B may be placed on respective sides of a driver's seat; in the case where the mobile terminal 800 is applied to a notebook computer, the overall size of the character input devices may be reduced to a size suitable for a single character input device and may be used as a full-sized keyboard.
Meanwhile, as described above, a plurality of characters (m characters) is assigned to each of the keys of the character input devices 810A and 810B. Whenever a user presses a key, the number of character strings obtainable through combination increases m times. Assuming that two (m=2) characters are assigned to each key and the length of a character string input by a user is n, 2n character strings can be obtained. For example, in the case where a user inputs the word ‘FOR’, character strings obtainable through combination are ‘JOU’, ‘JOR’, ‘JWU’, ‘JWR’, ‘FOU’, ‘FOR’, ‘FWU’ and ‘FWR’, that is, a total of 23=8 combination character strings.
If the length of an input character string increases, the number of character strings obtainable through combination increases in geometric progression. However, among such character strings obtained through combination, the number of significant character strings (character strings used as words in a current language system) is considerably low and the remaining character strings are merely insignificant simple arrangements of characters. As a result, in order to extract significant character strings from character strings, the number of which increases in geometric progression based on a user's input key sequence, the task of searching a word database 824 for character strings obtained through combination (combination character string), checking whether there is a matching word, and adding only a corresponding combination character string to a word list (hereinafter referred to as a ‘recommended word list’) if there is a matching word.
In a series of processes, the performance of the application (control program) used is a very important factor. The reason for this is that it is necessary to perform the task of comparing each of the combination character strings, the number of which increases in geometric progression whenever a key of the character input device 810A or 810B is pressed, with tens of thousands of words in the case where the total number of words in a word database 824 stored in the memory 820 is tens of thousands. Taking the problem of performance into consideration, the present invention assumes that the number of words used in real life is tens of thousands and chiefly aims to improve processing speed for searching so as to provide for the case where the performance of a processor (control module 830) used to implement the present invention is not high.
In more detail, it is difficult to expect to efficiently store tens of thousands of words in the word database 824 and check whether there is a word matching each of the combination character strings, generated by the pressing of a key, using the performance of a typical low specification processor for controlling a character input device. In order to solve the problem, the present invention employs a method of analyzing the elements of words and considerably reducing the number of words to be actually processed in the present invention.
In order to implement the above method, the construction of typical words used in real life is discussed below. As illustrated in
With the features of the construction of words taken into consideration, the word database 824 according to the present invention stores stems in a database form in advance and uses prefixes and suffixes, which can be combined with each stem, as conjugated prefixes and suffixes at the time of checking a character string for the specific stem. Unlike a desktop computer, for a mobile terminal, the size of memory therein is an important factor that should be considered in the design of the terminal, therefore it is necessary to reduce the size of the word database 824 as much as possible. Accordingly, as long as there is no problem with processing speed, the present invention employs a method of creating conjugated words during runtime as required and discarding the words after use, rather than storing the conjugated words, so as to prevent the size of memory for storing the word database 824 from increasing excessively. In the present embodiment, words stored in the word database 824 have stem forms, and it is preferred that DBs for prefixes and suffixes that the stems can have (a prefix DB and a suffix DB) be included.
For reference, assuming that there is an average of 10 conjugated words and the number of stems stored in the word database 824 is 10 thousand, the number of words that can be processed in the present invention is a total of 100 thousand (the number of stems×10). In reality, in the case of English, the number of conjugated words for each stem is greater than 10, and in the case of Korean, tens of conjugated words exist for each stem.
Assuming that the key sequence input by a user is in English, the process of generating the above-described recommended word list is described below. Prior to the description, input word character strings are classified into the following six types, and then the process is described:
1) words each composed of only a ‘stem’—for example, about, on, for
2) words each composed of a ‘stem’+a ‘suffix’—for example, nation+alize
3) words each composed of a ‘prefix’+a ‘stem’—for example, re+transmit
4) words each composed of a ‘prefix’+a ‘stem’+a ‘suffix’—for example, inter+nation+alization
5) words (compound words) each composed of a ‘first stem’+a ‘second stem’—for example, credit+card, and
6) words (compound words) each composed of a ‘first stem’+a ‘second stem’+a ‘suffix’
Referring to
At step S100 is included the step of determining whether the length of the character string is greater than 1 after adding the character to the character string buffer. If the length of the character string is greater than 1, the control module 830 detects the pressing of a key from the character input device 810A until the length of the character string is greater than 1.
Step S200 of generating all possible combination character strings using respective characters stored in the character string buffer is as described above, and another example thereof is as follows. Assuming that the character input device 810 is the right hand-dedicated character input device 300 of
Step S300 is a process of performing sequential processing while applying the above-described six types to each of the combination character strings generated at step S200, and includes step S310 of searching the word database 824 for each of the character strings on the assumption that the combination character string is a character string composed of a ‘stem’, as illustrated in
As illustrated in
Here, each of the combination character strings stored in the recommended word list may be stored along with information about the frequency of use of the combination character string. The reason for this is to help a user make a final selection by storing each of the combination character strings along with information about the frequency of use of the combination character string because a plurality of combination character strings may be stored in the recommended word list. In more detail, if a currently input character string is not the first word of a sentence, the value of the frequency of use may be adjusted by searching the word database 824 for the feature values of a character string input as a previous word (the part of speech of a word, and the various features of a word when the word forms a sentence, etc.) and considering the relationship between the previous word and the current word (context). By doing so, a specific word is frequently used. In the state in which a previous word is fixed to a specific word, the sequence of the recommended word list is adjusted in the case where another word is used more frequently, therefore words can be successively input without a user having to select a specific word.
Of course, it is preferred that the frequencies of use and the feature values be previously stored for respective words in the word database 824. Since the frequencies of use and the relationships between words may be applied to steps S320 to S360 in the same manner, descriptions thereof will be omitted below.
Thereafter, step S320, as illustrated in
At the step S320, in some cases, the stem may have a substring relationship to another stem. Accordingly, it is preferable to repeatedly search all ‘stem+suffix’ combinations for the corresponding combination character string.
Step S330, as shown in
Here, since, like the above-described step S320, the stem may have a substring relationship to another stem, it is preferable to sequentially search for all ‘prefix+stem’ combinations for the corresponding combination character string.
Referring to
Referring to
Finally, step S360, as illustrated in
Up to now, the process of generating a recommended word list has been made on the assumption that the key sequence input by a user is in English. The recommended word list generated after this process is output through the display device (not shown) of the mobile terminal 800. At this time, the character strings of the recommended word list may be arranged in descending sequence of frequency of use as described above. If the character string indicated in the uppermost part of the recommended word list is the character string desired to be input, a user selects the character string indicated in the uppermost part by pressing a space key (the key ‘SPACE’ shown in
Furthermore, the above-described step S300 is a so-called ‘word-level definition mode’. It is preferred that step S300 be performed whenever a user presses a key until he or she presses a space key (here, the phase “pressing of the space key” means the termination of input of a character string), and that the recommended word list be updated in real time whenever the user presses a key.
Through the recommended word list arranged according to the frequency of use as described above, the number of presses of keys and presses of a space key, in other words, except for the number of presses of keys for general character input, become less than 1, even though the number of times user definitely presses the ‘Alt’ key is taken into consideration.
Meanwhile, if the character string input by the user is not a word that is registered in the word database 824, the character string intended to be input by the user is not included in the recommended word list. In this case, by pressing an ESCAPE key (not shown) separately provided in the character input device 810A, the user can exit from the ‘word-level definition mode’ and then input the character string in a ‘character-level definition mode’. The term ‘character-level definition mode’ refers to a process in which a user positively indicates the intended character by pressing the ‘Alt’ key after each input character. By doing so, a user can input a new word character string that has been previously registered in the word database 824, and furthermore the user can add the input new word to the word database 824.
Most of the above-described process can be applied to Korean. However, in general, Korean has many cases where users do not accurately space words, unlike English. Provided that a user inputs Korean words according to the rules of Korean orthography, the process of generating a recommended word list can be simplified. However, most of the cases are otherwise. It is preferable to assume that a word and a word, or a character string and a character may be combined with each other. Furthermore, since a large number of Korean words can be successively combined with each other, unlike an English compound word, in which only two words are combined with each other, ‘phrase-level definition’ must be considered, therefore the amount of computational work for searching all combinations of words is estimated to be considerably larger than that for English, with the result that the process requires additional processing steps, unlike in the case of English.
A process of generating a recommended word list in the case where the key sequence input by the user is Korean is described in greater detail below with reference to the accompanying drawings.
Referring to
Thereafter, a combination character string is generated for respective characters stored in the character string buffer (preferably, characters assigned to pressed keys) at step S20. In this case, the combination character string is generated through the same process as the case of English. Illustrating the process in a structural fashion (in a tree form) to facilitate the following description on the assumption that the character string desired to be input is ‘’, the process may be illustrated as shown in
Thereafter, whether a first combination character string in a combination character string tree complies with the rule of Korean vowel and consonant combination is examined at step S30. As is well known, the rule governing the combination of Korean vowels and consonants is a rule that uses the special feature of Korean, and prescribes that the fundamental combination of a vowel and consonants of each word should be ‘initial sound+medial sound+final sound’ or ‘initial sound+medial sound’. For example, an initial sound must be a consonant (which may be a compound consonant, such as ‘’), a vowel (which may be a compound vowel, such as ‘’) should be placed after the initial sound, and finally a consonant should be placed at the location of the final consonant.
Step S30, if the corresponding combination character string complies with the rule of vowel and consonant combination, searches the word database 824 for a word that matches the assumed word on the assumption that the corresponding combination character string is a word having a prefix/stem/suffix combination at step S40. If there is a matching word, it is determined that the corresponding character string is a meaningful character string at step S50, and the corresponding character string is stored in the recommended word list and is displayed on the display device (not shown) of the mobile terminal 800 at step S60.
Meanwhile, if, as a result of the determination at step S30, the corresponding combination character string does not comply with the rule of vowel and consonant combination, the process deletes the corresponding combination character string and the part of a tree below the character string, moves to the location of the most recent meaningful character string (hereinafter referred to as ‘Backtracking’) and selects a subsequent combination character string at step S70, and returns to step S30 step. If, as a result of the determination at step S50, the corresponding combination character string is not a meaningful character string, the process returns to the above-described step S70.
Through the above-described steps S30 to S50 and step S70, in other words, the application of the rule of vowel and consonant combination to the combination character string and backtracking, the entire processing time can be considerably reduced. In more detail, with the above-described character string ‘’ taken as an example (refer to
From the above-described example, it can be seen that the number of steps and the amount of processing are considerably reduced through the rule of vowel and consonant combination and backtracking according to the present invention.
Although the description and the illustration have been provided in conjunction with the preferred embodiment for the illustration of the technical spirit of the present invention, the present invention is not limited to the illustrated and described construction and operation, but those skilled in the art can appreciate that various variations and modifications are possible without departing from the scope of the spirit of the present invention. Accordingly, all appropriate variations, modifications and equivalents must be considered to fall within the scope of the present invention.
According to the above-described present invention, characters can be rapidly and accurately input in a touch typing manner even in a mobile environment, and the number of presses of keys for the input of a single character can be minimized.
Furthermore, according to the present invention, how to use thereof can be easily acquired by adopting a mirror-image symmetrical character arrangement based on the ‘Sholes’ character arrangement.
Number | Date | Country | Kind |
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10-2005-0100753 | Oct 2005 | KR | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/KR2006/004323 | 10/23/2006 | WO | 00 | 3/31/2008 |