Electronic dictionary and recording medium to record dictionary information display control program

An electronic dictionary including: a dictionary storage unit to store dictionary information in which headwords and explanation information are correlated, respectively; an input unit; a CPU to retrieve a headword corresponding to the search string inputted by the input unit from the dictionary storage unit, display the headword in a headword list, read, from the dictionary storage unit, explanation information of a headword selected from the list, and display the explanation information; and a keyword registration unit to register an inputted keyword correlated with the headword whose explanation information is displayed, wherein the CPU retrieves a headword correlated with a keyword corresponding to the search string from the keyword registration unit when the search string is inputted by the input unit in a state where the keyword correlated with the headword is registered in the keyword registration unit, and adds the headword to the headword list to display the headword.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electronic dictionary and a recording medium to record a dictionary information display control program.

2. Description of the Related Art

Conventionally, an electronic dictionary having a dictionary function includes a dictionary database which stores headwords and explanation information of the headwords being correlated with each other, respectively. The electronic dictionary is structured to read the explanation information of a headword from the dictionary database, the headword which corresponds to an inputted word, and to display the headword and the explanation information on a display.

Currently, in such an electronic dictionary, a keyword is attached to a headword by a user, and the headword can be retrieved by using the keyword, accordingly.

However, since a headword is retrieved by using an attached keyword by the above-mentioned art, unless a user remembers what keyword is attached to the headword, the headword cannot be retrieved by using the keyword. As a result, a problem arises that retrieval thereof is performed inefficiently.

SUMMARY OF THE INVENTION

The present invention is made in view of the circumstances, and there is provided an electronic dictionary which can efficiently retrieve explanation information of a headword to which a keyword is attached, and a recording medium to record a program for efficiently retrieving explanation information of a headword to which a keyword is attached.

To solve the problem mentioned above, a first aspect of the present invention is an electronic dictionary including: a dictionary storage unit to store dictionary information in which a plurality of headwords and a plurality of explanation information are correlated with each other, respectively; an input unit to input a search string based on a user operation; a headword list display control unit to retrieve at least one headword from the dictionary storage unit, the at least one headword corresponding to the search string inputted by the input unit, and to display the at least one retrieved headword in a headword list; an explanation information display control unit to read explanation information from the dictionary storage unit, the explanation information which is for a headword selected based on a user operation from among the at least one retrieved headword in the headword list displayed by the headword list display control unit, and to display the read explanation information; and a keyword registration unit to register a keyword which is inputted based on a user operation and the headword whose explanation information is displayed by the explanation information display control unit, the keyword and the headword being correlated with each other, wherein the headword list display control unit includes a keyword-addition-to-headword unit to retrieve a headword correlated with a keyword corresponding to the search string and registered in the keyword registration unit from among at least one headword registered in the keyword registration unit when the search string is inputted by the input unit in a state where the keyword is correlated with the headword and registered in the keyword registration unit, and to add the retrieved headword correlated with the keyword corresponding to the inputted search string and registered in the keyword registration unit to the headword list so as to display the retrieved headword correlated with the keyword corresponding to the inputted search string and registered in the keyword registration unit.

A second aspect of the present invention is a recording medium to record a dictionary information display control program for a computer including a dictionary storage unit to store dictionary information in which a plurality of headwords and a plurality of explanation information are correlated with each other, respectively, to display the dictionary information, the recording medium making the computer function as: an input unit to input a search string based on a user operation; a headword list display control unit to retrieve at least one headword from the dictionary storage unit, the at least one headword corresponding to the search string inputted by the input unit, and to display the at least one retrieved headword in a headword list; an explanation information display control unit to read explanation information from the dictionary storage unit, the explanation information which is for a headword selected based on a user operation from among the at least one retrieved headword in the headword list displayed by the headword list display control unit, and to display the read explanation information; and a keyword registration unit to register a keyword which is inputted based on a user operation and the headword whose explanation information is displayed by the explanation information display control unit, the keyword and the headword being correlated with each other, wherein the headword list display control unit includes a keyword-addition-to-headword unit to retrieve a headword correlated with a keyword corresponding to the search string inputted by the input unit and registered in the keyword registration unit from among at least one headword registered in the keyword registration unit when the search string is inputted by the input unit in a state where the keyword is correlated with the headword and registered in the keyword registration unit, and to add the retrieved headword correlated with the keyword corresponding to the inputted search string and registered in the keyword registration unit to the headword list so as to display the retrieved headword correlated with the keyword corresponding to the inputted search string and registered in the keyword registration unit.

According to the aspects of the present invention, when at least one headword corresponding to an inputted search string is retrieved from the dictionary storage unit, the at least one retrieved headword is displayed in a headword list. Then, a headword is selected from among the at least one retrieved headword in the headword list based on a user operation, and the explanation information of the selected headword is read from the dictionary information and displayed. When a keyword inputted based on a user operation is registered in the keyword registration unit, the keyword being correlated with the headword whose explanation information is displayed, and the search string is inputted thereafter, the headword correlated with the keyword which corresponds to the search string and registered in the keyword registration unit is retrieved from at least one headword registered in the keyword registration unit, and added to the headword list so as to be displayed. Accordingly, even when what keyword is attached to what headword is not remembered, a keyword corresponding to a search string is detected, a headword correlated with the keyword and registered in the keyword registration unit is retrieved, and the retrieved headword is added to a headwork list so as to be displayed. Consequently, retrieval of a headword to which a keyword is attached can be performed in addition to the standard headword retrieval without being aware that a keyword is attached to a retrieval-target headword. Accordingly, retrieval of a headword to which a user attaches a keyword can be performed efficiently.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1is a plane view of an electronic dictionary1.

As shown inFIG. 1, the electronic dictionary1includes a main-display10, a sub-display11, and a key set2.

The main-display10and the sub-display11display various data such as letters and symbols based on user operations of the key set2, and are composed of a liquid crystal display (LCD), an electronic luminescent display (ELD), or the like, respectively. The main-display10and the sub-display11according to an embodiment of the present invention are integrated with a touch panel110(shown inFIG. 2), so that by depressing a surface of the touch panel110, an input operation according to a depressed position on the touch panel110becomes available.

The key set2includes various keys for a user to operate the electronic dictionary1. More specifically, the key set2includes a translation/determination key2b, letter keys2c, dictionary selection keys2d, cursor keys2e, a shift key2f, and a return/list key2g.

The translation/determination key2bis used for execution of retrieval, determination of a headword, and the like. The letter keys2care used for inputting a word by a user, and the like. The letter keys2caccording to the embodiment of the present invention include keys A to Z. The dictionary selection keys2dare used for selecting a dictionary (or encyclopedia) database820(shown inFIG. 2) described below.

The cursor keys2eare used for moving a reverse display position in a screen, namely, a cursor position in the screen, and the like. In the embodiment of the present invention, the cursor keys2ecan specify a direction to move the position, namely, to move up, down, left or right. The shift key2fis used when a Japanese word is set as a retrieval target, and the like. The return/list key2gis used for returning to a screen previously displayed, and the like.

Next, the internal structure of the electronic dictionary1is described.FIG. 2is a block diagram showing the internal structure of the electronic dictionary1.

As shown inFIG. 2, the electronic dictionary1includes a display unit40, an input unit30, a central processing unit (CPU)20, a flash read only memory (ROM)80, and a random access memory (RAM)90. The units and the like are connected with each other through a bus100so as to have data communications with each other.

The display unit40includes the main-display10and the sub-display11, which are mentioned above, and displays various information on the main-display10and the sub-display11based on display signals inputted from the CPU20.

The input unit30includes the key set2and the touch panel110, which are mentioned above, and outputs a signal to the CPU20, the signal corresponding to a key, which is depressed, of the key set2or a depressed position on the touch panel110.

The CPU20performs processing based on a prescribed program according to an inputted instruction, and transfers the instruction and/or data to each unit, and the like, so as to control the electronic dictionary1as a whole. More specifically, the CPU20reads each program stored in the flash ROM80in response to each operation signal and the like inputted from the input unit30, and performs processing according to the read program. Then, the CPU20stores the result of the processing in the RAM90, and appropriately outputs the result of the processing to the display unit40.

The flash ROM80is a memory to store programs and data for executing various functions of the electronic dictionary1. In the embodiment of the present invention, the flash ROM stores an information display program81, a dictionary/encyclopedia database set82, a keyword registration table84, and the like.

The information display program81is a program in the present invention, and allows the CPU20to perform dictionary/encyclopedia retrieval processing (shown inFIG. 5) described below.

The dictionary/encyclopedia database set82includes a plurality of databases820. In the embodiment of the present invention, the dictionary/encyclopedia database set82includes a dictionary database820aof an English to Japanese dictionary, a dictionary database820bof “Ko*en” (Japanese dictionary), a dictionary database820cof “Mei* Japanese Dictionary”, and an encyclopedia database820dof a ceremonial occasion encyclopedia.

As shown in PART (a) ofFIG. 3, a plurality of headwords, a plurality of explanation information, and the like are stored in each of the dictionary databases820ato820c. The plurality of headwords, the plurality of explanation information, and the like are correlated with each other, respectively, therein. Explanation information is composed of the meaning content of a headword.

A plurality of categories, a plurality of explanation information, and the like are stored in the encyclopedia database820d. The plurality of categories, the plurality of explanation information, and the like are correlated with each other, respectively, therein. As shown in PART (b) ofFIG. 3, the data structure of the encyclopedia database820daccording to the embodiment of the present invention is a hierarchy structure. The categories are divided into large categories, medium categories, and small categories. A plurality of medium categories is included in the content of each large category, a plurality of small categories is included in the content of each medium category, and each small category is correlated with its explanation information.

As shown in PART (c) ofFIG. 3, the keyword registration table84accumulates and stores titles of the dictionary (or encyclopedia) databases820, headwords (or small categories) stored in the databases820, keywords and comments inputted by a user, and language types of the keywords, all of which are correlated with each other, respectively, in keyword registration processing (shown inFIG. 8) described below.

The RAM90includes a memory region to temporality store various programs which the CPU20executes and data and the like for executing the programs. In the embodiment of the present invention, the RAM90includes a selected dictionary storage region91.

In the selected dictionary storage region91, the title of a dictionary (or encyclopedia) database820selected by a user as a search area for a headword is stored.

Next, operation of the electronic dictionary1is described.

FIGS. 4 to 8are flow charts showing the sequence of steps of the dictionary/encyclopedia retrieval processing which the CPU20performs by reading the information display program81.

In the dictionary/encyclopedia retrieval processing, when the explanation information of a headword (or small category) is retrieved from a database820which is a search area, and displayed, a keyword registration button111(shown in PART (b) ofFIG. 9) for instructing registration of a keyword or a comment with the headword (or small category) is displayed on the sub-display11. When a user operation for registering a keyword or a comment is performed through the keyword registration button111, the keyword registration processing shown inFIG. 8is performed. (Refer to Step T15ofFIG. 5, Step V15ofFIG. 6, and Step W11ofFIG. 7.) The detail of the dictionary/encyclopedia retrieval processing is described below.

In the following, first, the keyword registration processing is described, and the dictionary/encyclopedia retrieval processing is described thereafter, for convenience.

FIG. 8shows a flow chart showing the sequence of steps of the keyword registration processing as a sub-routine of the dictionary/encyclopedia retrieval processing.

As shown inFIG. 8, when the keyword registration processing is performed by the user operation for registering a keyword or a comment, the CPU20, first, displays a keyword input button112for instructing a start of a keyword input and a comment input button113for instructing a start of a comment input on the sub-display11(shown in PART (c) ofFIG. 9). Then, the CPU20judges whether a keyword input is selected by the user or not (Step U1). At the time, the CPU20divides a display region of the main-display10into two display areas. One of the display areas keeps displaying the explanation information of a headword (or small category), the explanation information which is displayed, and the other of the display areas displays an input frame for inputting an English keyword and an input frame for inputting a Japanese keyword.

When the CPU20judges that the keyword input is selected at Step U1(Step U1; YES), the CPU20judges whether an English keyword input is selected or not based on whether the input frame for inputting an English keyword is selected or not (Step U2).

When the CPU20judges that the English keyword input is selected at Step U2(Step U2; YES), the CPU accepts an input of an English keyword into the selected input frame from the user (Step U3). In the embodiment of the present invention, the keyword may be inputted by operating the key set2or by handwriting on the touch panel110of the sub-display11.

Next, the CPU20correlates the inputted keyword and its language type (in this case, English) with the title of the dictionary (or encyclopedia) database820which is the search area at the time and the headword (or small category) whose explanation information is displayed, registers the inputted keyword and its language type correlated with the title of the dictionary (or encyclopedia) database820and the headword (or small category) in the keyword registration table84(Step U4), and then moves to Step U1described above.

When the CPU20judges that the English keyword input is not selected at Step U2(Step U2; NO), the CPU20judges whether a Japanese keyword input is selected or not based on whether the input frame for inputting a Japanese keyword is selected or not (Step U5).

When the CPU20judges that the Japanese keyword input is not selected at Step U5(Step U5; NO), the CPU20moves to other processing.

When the CPU20judges that the Japanese keyword input is selected at Step U5(Step U5; YES), the CPU accepts an input of a Japanese keyword into the selected input frame from the user (Step U6). In the embodiment of the present invention, the keyword may be inputted by operating the key set2or by handwriting on the touch panel110of the sub-display11.

Next, the CPU20correlates the inputted keyword and its language type (in this case, Japanese) with the title of the dictionary (or encyclopedia) database820which is the search area at the time and the headword (or small category) whose explanation information is displayed, registers the inputted keyword and its language type correlated with the title of the dictionary (or encyclopedia) database820and the headword (or small category) in the keyword registration table84(Step U7), and then moves to Step U1described above.

When the CPU20judges that the keyword input is not selected at Step U1(Step U1; NO), the CPU20judges whether a comment input is selected by the user or not (Step U8).

When the CPU20judges that the comment input is selected at Step U8(Step U8; YES), the CPU20displays at least one keyword on the main-display in a list form (Step U9), the keyword being correlated with the headword (or small category) whose explanation information is displayed, and being registered in the keyword registration table84.

When the user selects a keyword to which a comment is to be attached (Step U10), and the comment to be attached is inputted (Step U11), the CPU20correlates the inputted comment with the selected keyword, the title of the dictionary (or encyclopedia) database820which is the search area at the time, and the headword (or small category) whose explanation information is displayed, and registers the inputted comment correlated with the selected keyword, the title of the dictionary (or encyclopedia) database820, and the headword (or small category) in the keyword registration table84(Step U12). In the embodiment of the present invention, the comment may be inputted by operating the key set2or by handwriting on the touch panel110of the sub-display11.

When the CPU20judges that the comment input is not selected at Step U8(Step U8; NO), the CPU20judges whether an operation for completing registration is performed or not (Step U13). When the CPU20judges that the operation for completing registration is not performed at Step U13(Step U13; NO), the CPU20moves to other processing.

When the CPU20judges that the operation for completing registration is performed at Step U13(Step U13; YES), the CPU displays a registration-completed message on the main-display10(Step U14), and ends the keyword registration processing thereafter.

In the above-described keyword registration processing according to the embodiment of the present invention, a plurality of keywords and comments can be attached to one headword (or small category).

Next, the dictionary/encyclopedia retrieval processing is described referring toFIGS. 4 to 8.

As shown inFIG. 4, when a user selects one of the databases820stored in the flash ROM80as a search area by one of the dictionary selection keys2d(Step S1) after the dictionary/encyclopedia retrieval processing is performed, the CPU20judges whether the database820selected as the search area is the dictionary database820aof the English to Japanese dictionary or not (Step S2) after storing the title of the selected database820in the selected dictionary storage region91.

When the CPU20judges that the database820selected as the search area is the dictionary database820aof the English to Japanese dictionary at Step S2(Step S2; YES), the CPU20performs English to Japanese dictionary retrieval processing (Step S3).

More specifically, as shown inFIG. 5, in the English to Japanese dictionary retrieval processing, the CPU20, first, displays an input screen for inputting a search string on the main-display10(Step T1). At Step T1, the CPU20displays an input frame in the input screen, the input frame for inputting a search string in order to retrieve a headword in a language type of the headwords stored in the dictionary database820aof the English to Japanese dictionary, namely, English.

Next, the CPU20judges whether a Japanese keyword is correlated with the dictionary database820aof the English to Japanese dictionary and registered in the keyword registration table84by the keyword registration processing (shown inFIG. 8) described above or not (Step T2). When the CPU20judges that a Japanese keyword is not correlated with the dictionary database820aof the English to Japanese dictionary and registered in the keyword registration table84at Step T2(Step T2; NO), the CPU20moves to Step T4described below.

When the CPU20judges that a Japanese keyword is correlated with the dictionary database820aof the English to Japanese dictionary and registered in the keyword registration table84at Step T2(Step T2; YES), the CPU20displays an input frame in the input screen, the input frame for inputting a search string in order to retrieve a headword in a language type of Japanese (Step T3). Namely, when a keyword is registered in a language type (Japanese) which is different from the language type (English) of the headwords stored in the dictionary database820aof the English to Japanese dictionary, an input frame for the language type (Japanese) of the keyword is displayed in the input screen.

Next, the CPU20judges whether headword retrieval in English is selected or not based on whether the input frame for English is selected by the user or not (Step T4).

When the CPU20judges that the headword retrieval in English is selected at Step T4(Step T4; YES), the CPU accepts an input of an English search string into the selected input frame from the user (Step T5).

Next, the CPU20judges whether an English keyword is correlated with the dictionary database820aof the English to Japanese dictionary and registered in the keyword registration table84by the keyword registration processing (shown inFIG. 8) described above or not (Step T6).

When the CPU20judges that an English keyword is not correlated with the dictionary database820aof the English to Japanese dictionary and registered in the keyword registration table84at Step T6(Step T6; NO), the CPU20retrieves at least one headword corresponding to the search string, or more specifically, at least one headword which agrees with the search string in the prefix (or in the first letter at least), from the dictionary database820aof the English to Japanese dictionary (Step T20), displays the at least one retrieved headword as a headword list on the main-display10(Step T21), and moves to Step T9described below thereafter.

When the CPU20judges that an English keyword is correlated with the dictionary database820aof the English to Japanese dictionary and registered in the keyword registration table84at Step T6(Step T6; YES), the CPU20retrieves at least one headword corresponding to the search string from the dictionary database820aof the English to Japanese dictionary and also retrieves at least one headword correlated with a keyword corresponding to the search string and registered in the keyword registration table84from among at least one headword registered in the keyword registration table84(Step T7).

Next, the CPU20displays the at least one retrieved headword as a headword list on the main-display10(Step T8), and moves to Step T9described below. More specifically, at Step T8, the CPU20displays, among the at least one headword retrieved from the dictionary database820aof the English to Japanese dictionary, a headword which completely agrees with the search string at the top of the headword list, and displays the headword retrieved from the keyword registration table84immediately under the headword which completely agrees with the search string in the headword list. At the time, the CPU20displays the headword retrieved from the keyword registration table84so as to be distinguishable in the headword list. In the embodiment of the present invention, the CPU20displays the headword retrieved from the keyword registration table84so as to be distinguishable by changing a display color thereof or a line width thereof, but another way can be used therefor.

When the CPU20judges that the headword retrieval in English is not selected at Step T4(Step T4; NO), the CPU judges whether headword retrieval in Japanese is selected or not based on whether the input frame for Japanese is selected by the user or not (Step T30).

When the CPU judges that the headword retrieval in Japanese is not selected at Step T30(Step T30; NO), the CPU20moves to other processing.

When the CPU judges that the headword retrieval in Japanese is selected at Step T30(Step T30; YES), the CPU accepts an input of a Japanese search string into the selected input frame from the user (Step T31).

Next, the CPU20retrieves at least one headword correlated with a keyword corresponding to the search string (in this case, Japanese search string) and registered in the keyword registration table84from among at least one headword registered in the keyword registration table84(Step T32).

The CPU20displays the retrieved headword on the main-display10as a headword list (Step T33).

Then, the CPU20judges whether a headword of the at least one headword in the headword list is specified (temporarily selected) by the user through the cursor keys2eor not (Step T9).

When the CPU20judges that a headword of the headword in the headword list is specified at Step T9(Step T9; YES), the CPU20judges whether a comment is correlated with the specified headword and registered in the keyword registration table84or not (Step T10). When the CPU20judges that a comment is not correlated with the specified headword and registered in the keyword registration table84at Step T10(Step T10; NO), the CPU20moves to Step T9described above.

When the CPU20judges that a comment is correlated with the specified headword and registered in the keyword registration table84at Step T10(Step T10; YES), the CPU20displays the comment on the sub-display11(Step T11), and moves to Step T9described above thereafter.

When the CPU20judges that a headword of the at least one headword in the headword list is not specified at Step T9(Step T9; NO), the CPU20judges whether a headword is selected from the at least one headword in the headword list by the user through the cursor keys2eand the translation/determination key2bor not (Step T12).

When the CPU20judges that a headword is not selected from the headword in the headword list at Step T12(Step T12; NO), the CPU20moves to other processing.

When the CPU20judges that a headword is selected from the headword in the headword list at Step T12(Step T12; YES), the CPU20reads the explanation information of the selected headword from the dictionary database820aof the English to Japanese dictionary, and displays the read explanation information on the main-display10(Step T13). At the time, the CPU20displays the keyword registration button111on the sub-display11.

Next, the CPU20judges whether the operation for registering a keyword or a comment is performed by the user or not based on whether the keyword registration button111is operated or not (Step T14). When the CPU20judges that the operation for registering a keyword or a comment is not performed at Step T14(Step T14; NO), the CPU20moves to other processing.

When the CPU20judges that the operation for registering a keyword or a comment is performed at Step T14(Step T14; YES), the CPU20performs the keyword registration processing (shown inFIG. 8) described above (Step T15). Consequently, a keyword or a comment is correlated with a retrieved headword, and registered in the keyword registration table84.

When the keyword registration processing is completed, the CPU20ends the English to Japanese dictionary retrieval processing and the dictionary/encyclopedia retrieval processing, as shown inFIGS. 4 and 5.

As shown inFIG. 4, when the CPU20judges that the database820selected as the search area is not the dictionary database820aof the English to Japanese dictionary at Step S2(Step S2; NO), the CPU20judges whether the database820selected as the search area is Japanese-related dictionaries or not (Step S4). When the Japanese-related dictionaries is selected as the search area, Japanese-related dictionaries such as the dictionary database820bof “Ko*en” (Japanese dictionary), the dictionary database820cof “Mei* Japanese Dictionary”, a Japanese to English dictionary, an encyclopedia, and other dictionaries with which at least one Japanese word is correlated (the ceremonial occasion encyclopedia in the embodiment of the present invention), all of which are retrievable in Japanese, are the search area.

When the CPU20judges that the databases820selected as the search area is the Japanese-related dictionaries which are retrievable in Japanese (Step S4; YES), the CPU20performs the Japanese-related dictionaries retrieval processing (Step S5).

More specifically, as shown inFIG. 6, in the Japanese-related dictionaries retrieval processing, the CPU20, first, displays an input screen for inputting a search string on the main-display10(Step V1). At Step V1, the CPU20displays an input frame in the input screen, the input frame for inputting a search string in order to retrieve a headword in a language type of headwords stored in Japanese-related dictionaries such as the databases820band820cof the Japanese dictionaries, namely, Japanese.

Next, the CPU20accepts an input of a Japanese search string into the selected input frame from the user (Step V5).

Then, the CPU20judges whether a Japanese keyword is correlated with a database820of the databases820of the dictionary/encyclopedia database set82and registered in the keyword registration table84by the keyword registration processing (shown inFIG. 8) described above or not (Step V6).

When the CPU20judges that a Japanese keyword is not correlated with a database820of the databases820of the dictionary/encyclopedia database set82and registered in the keyword registration table84at Step V6(Step V6; NO), the CPU20retrieves at least one headword corresponding to the search string from the Japanese-related dictionaries (Step V20), displays the at least one retrieved headword as a headword list on the main-display10(Step V21), and moves to Step V9described below thereafter. At Step V21, the CPU20correlates the title of a dictionary database820with a headword in the headword list, the dictionary database820from which the headword is retrieved, and displays the title thereof correlated with the headword on the main-display10, with regard to each headword in the headword list.

When the CPU20judges that a Japanese keyword is correlated with a database820of the databases820of the dictionary/encyclopedia database set82and registered in the keyword registration table84at Step V6(Step V6; YES), the CPU20retrieves at least one headword corresponding to the search string from the Japanese-related dictionaries such as the dictionary databases820band820cof the Japanese dictionaries, and also retrieves at least one headword and/or small category which is correlated with a keyword corresponding to the search string and registered in the keyword registration table84from among at least one headword and/or small category registered in the keyword registration table84(Step V7).

Next, the CPU20displays the retrieved headwords and/or small categories as the headword list on the main-display10(Step V8). More specifically, at Step V8, the CPU20correlates the headword retrieved from the databases820of the Japanese-related dictionaries with the title of a database820from which the headword is retrieved, and also correlates the headword and/or small category retrieved from the keyword registration table84with the title of a dictionary and/or encyclopedia which is correlated with the retrieved headword and/or small category and which is registered in the keyword registration table84, so as to display the retrieved headwords and/or small categories with the titles on the main-display10. The CPU20displays, among the headword retrieved from the Japanese-related dictionaries such as the dictionary databases820band820cof the Japanese dictionaries, a headword which completely agrees with the search string at the top of the headword list, and displays the headword and/or small category retrieved from the keyword registration table84immediately under the headword which completely agrees with the search string in the headword list. At the time, the CPU20displays the headword and/or small category retrieved from the keyword registration table84so as to be distinguishable in the headword list. In the embodiment of the present invention, the CPU20displays the headword and/or small category retrieved from the keyword registration table84so as to be distinguishable by changing a display color thereof or a line width thereof, but another way can be used therefor.

Next, the CPU20judges whether a headword or small category of the headword and small category in the headword list is specified (temporarily selected) by the user through the cursor keys2eor not (Step V9).

When the CPU20judges that a headword or small category of the headword and small category in the headword list is specified at Step V9(Step V9; YES), the CPU20judges whether a comment is correlated with the specified headword or small category and registered in the keyword registration table84or not (Step V10). When the CPU20judges that a comment is not correlated with the specified headword or small category and registered in the keyword registration table84at Step V10(Step V10; NO), the CPU20moves to the Step V9described above.

When the CPU20judges that a comment is correlated with the specified headword or small category and registered in the keyword registration table84at Step V10(Step V10; YES), the CPU20displays the comment on the sub-display11(Step V11), and moves to Step V9described above thereafter.

When the CPU20judges that a headword or small category of the headword and small category in the headword list is not specified at Step V9(Step V9; NO), the CPU20judges whether a headword or small category is selected from the headword and small category in the headword list by the user through the cursor keys2eand the translation/determination key2bor not (Step V12).

When the CPU20judges that a headword or small category is not selected from the headword and small category in the headword list at Step V12(Step V12; NO), the CPU20moves to other processing.

When the CPU20judges that a headword or small category is selected from the headword and/or small category in the headword list at Step V12(Step V12; YES), the CPU20reads the explanation information of the selected headword or small category from the dictionary (or encyclopedia) database820whose title is displayed, and displays the read explanation information on the main-display10(Step V13). At the time, the CPU20displays the keyword registration button111on the sub-display11.

Next, the CPU20judges whether the operation for registering a keyword or a comment is performed by the user or not based on whether the keyword registration button111is operated or not (Step V14). When the CPU20judges that the operation for registering a keyword or a comment is not performed at Step V14(Step V14; NO), the CPU20moves to other processing.

When the CPU20judges that the operation for registering a keyword or a comment is performed at Step V14(Step V14; YES), the CPU20performs the keyword registration processing (shown inFIG. 8) described above (Step V15). Consequently, a keyword or a comment is correlated with a retrieved headword or small category and registered in the keyword registration table84.

When the keyword registration processing is completed, the CPU20ends the Japanese-related dictionaries retrieval processing and the dictionary/encyclopedia retrieval processing, as shown inFIGS. 4 and 6.

As shown inFIG. 4, when the CPU20judges that the database820selected as the search area is not the Japanese-related dictionaries at Step S4(Step S4; NO), the CPU20judges whether the database820selected as the search area is the encyclopedia database820dor not (Step S6). When the CPU20judges that the database820selected as the search area is not the encyclopedia database820dat Step S6(Step S6; NO), the CPU20moves to other processing.

When the CPU20judges that the database820selected as the search area is the encyclopedia database820dat Step S6(Step S6; YES), the CPU20performs the ceremonial occasion encyclopedia retrieval processing (Step S7).

More specifically, as shown inFIG. 7, in the ceremonial occasion encyclopedia retrieval processing, the CPU20, first, displays a category selection screen for selecting a large category as a search area on the main-display10(Step W1). At Step W1, the CPU20displays large categories stored in the encyclopedia database820dof the ceremonial occasion encyclopedia in a list form in the category selection screen in a state where a large category can be selected therefrom.

Next, the CPU20judges whether a Japanese keyword is correlated with the encyclopedia database820dof the ceremonial occasion encyclopedia and registered in the keyword registration table84by the keyword registration processing (shown inFIG. 8) described above or not (Step W2). When the CPU20judges that a Japanese keyword is not correlated with the encyclopedia database820dof the ceremonial occasion encyclopedia and registered in the keyword registration table84at Step W2(Step W2; NO), the CPU20moves to Step W4described below.

When the CPU20judges that a Japanese keyword is correlated with the encyclopedia database820dof the ceremonial occasion encyclopedia and registered in the keyword registration table84at Step W2(Step W2; YES), the CPU20displays an input frame in the category selection screen, the input frame for inputting a search string in order to retrieve a small category in a language type of Japanese (Step W3).

Next, the CPU20judges whether an English keyword is correlated with the encyclopedia database820dof the ceremonial occasion encyclopedia and registered in the keyword registration table84by the keyword registration processing (shown inFIG. 8) described above or not (Step W4). When the CPU20judges that an English keyword is not correlated with the encyclopedia database820dof the ceremonial occasion encyclopedia and registered in the keyword registration table84at Step W4(Step W4; NO), the CUP20moves to Step W6described below.

When the CPU20judges that an English keyword is correlated with the encyclopedia database820dof the ceremonial occasion encyclopedia and registered in the keyword registration table84at Step W4(Step W4; YES), the CPU20displays an input frame in the category selection screen, the input frame for inputting a search string in order to retrieve a small category in a language type of English (Step W5).

Next, the CPU20judges whether a large category is selected from the large categories by a user through the category selection screen or not (Step W6). When the CPU20judges that a large category is selected from the large categories at Step W6(Step W6; YES), the CPU20displays medium categories of the selected large category on the main-display10in a list form in a state where a medium category can be selected from the medium categories (Step W7).

When a medium category is selected from the medium categories by the user, small categories of the selected medium category are displayed on the main-display10in a state where a small category can be selected from the small categories. When a small category is selected from the small categories by the user (Step W8), the CPU20reads the explanation information of the selected small category from the encyclopedia database820d, and displays the read explanation information on the main-display10(Step W9). At the time, the CPU20displays the keyword registration button111on the sub-display11.

Next, the CPU20judges whether the operation for registering a keyword or a comment is performed by the user or not based on whether the keyword registration button111is operated or not (Step W10). When the CPU20judges that the operation for registering a keyword or a comment is not performed at Step W10(Step W10; NO), the CPU20moves to other processing.

When the CPU20judges that the operation for registering a keyword or a comment is performed at Step W10(Step W10; YES), the CPU20performs the keyword registration processing (shown inFIG. 8) described above (Step W11). Consequently, a keyword or a comment is correlated with a retrieved small category and registered in the keyword registration table84.

When the keyword registration processing is completed, the CPU20ends the ceremonial occasion encyclopedia retrieval processing and the dictionary/encyclopedia retrieval processing, as shown inFIGS. 4 and 7.

When the CPU20judges that a large category is not selected from the large categories at Step W6(Step W6; NO), the CPU20judges whether a category retrieval in Japanese is selected or not based on whether the input frame for Japanese is selected by the user or not (Step W12).

When the CPU20judges that the category retrieval in Japanese is selected at Step W12(Step W12; YES), the CPU20accepts an input of a Japanese search string into the selected input frame from the user (Step W13).

Next, the CPU20retrieves at least one small category correlated with a keyword corresponding to the search string from among at least one small category registered in the keyword registration table84(Step W14), and moves to Step W18described below thereafter.

When the CPU20judges that the category retrieval in Japanese is not selected at Step W12(Step W12; NO), the CPU20judges whether a category retrieval in English is selected or not based on whether the input frame for English is selected by the user or not (Step W15).

When the CPU20judges that the category retrieval in English is not selected at Step W15(Step W15; NO), the CPU20moves to other processing.

When the CPU20judges that the category retrieval in English is selected at Step W15(Step W15; YES), the CPU20accepts an input of an English search string into the selected input frame from the user (Step W16).

Next, the CPU20retrieves at least one small category correlated with a keyword corresponding to the search string from among the at least one small category registered in the keyword registration table84(Step W17).

Then, the CPU20displays the at least one retrieved small category on the main-display in a list form (Step W18), and judges a small category of the small category in the list is specified (temporarily selected) by the user through the cursor keys2eor not (Step W19).

When the CPU20judges that a small category of the small category in the list is specified at Step W19(Step W19; YES), the CPU20judges whether a comment is correlated with the specified small category and registered in the keyword registration table84or not (Step W20). When the CPU20judges that a comment is not correlated with the specified small category and registered in the keyword registration table84at Step W20(Step W20; NO), the CPU20moves to Step W19described above.

When the CPU20judges that a comment is correlated with the specified small category and registered in the keyword registration table84at Step W20(Step W20; YES), the CPU20displays the comment on the sub-display11(Step W21), and moves to Step W19described above thereafter.

When the CPU20judges that a small category of the small category in the list is not specified at Step W19(Step W19; NO), the CPU20judges whether a small category is selected from the small category in the list by the user through the cursor keys2eand the translation/determination key2bor not (Step W22).

When the CPU20judges that a small category is not selected from the small category in the list at Step W22(Step W22; NO), the CPU20moves to other processing.

When the CPU20judges that a small category is selected from the small category in the list at Step W22(Step W22; YES), the CPU20reads the explanation information of the selected small category from the encyclopedia database820d, displays the read explanation information on the main-display10(Step W23), and moves to Step W10described above thereafter. At Step W23, the CPU20displays the keyword registration button111on the sub-display11.

Embodiments of Operation

Next, the dictionary/encyclopedia retrieval processing is described in detail referring toFIGS. 9 to 17.

First Embodiment of Operation

First, as shown in PART (a) ofFIG. 9, when a user selects the dictionary database820aof the English to Japanese dictionary as a search area (Step S2; YES), the input screen including the input frame for inputting an English search string is displayed on the main-display10(Step T1).

When the user selects the input frame for inputting an English search string (Step T4; YES), and inputs an English search string “have” therein (Step T5), headwords “have” and the like corresponding to the English search string “have” are retrieved from the dictionary database820aof the English to Japanese dictionary (Step T20) by being judged that there is no English keyword correlated with the dictionary database820aof the English to Japanese dictionary and registered in the keyword registration table84(Step T6; NO). The retrieved headwords “have” and the like are displayed on the main-display10as a headword list (Step T21).

When the headword “have” is selected from among the headwords “have” and the like in the headword list (Step T12; YES), as shown in PART (b) ofFIG. 9, the explanation information of the selected headword “have” is read from the dictionary database820aof the English to Japanese dictionary and displayed on the main-display (Step T13). Then, the keyword registration button111is displayed on the sub-display11.

When the operation for registering a keyword or a comment is performed by the user through the keyword registration button111(Step T14; YES), as shown in PART (c) ofFIG. 9, the input frame for inputting an English keyword and the input frame for inputting a Japanese keyword are displayed on the main-display10. In addition, the keyword input button112for instructing a start of inputting a keyword and the comment input button113for instructing a start of inputting a comment are displayed on the sub-display11(Step U1).

When, as shown in PART (c) and PART (d) ofFIG. 9, the user selects the English keyword input (Step U1; YES, Step U2; YES), and inputs an English keyword “eat” on the touch panel110of the sub-display11by handwriting (Step U3), the inputted keyword “eat” and its language type “English” are correlated with the title “English to Japanese dictionary” of the dictionary database820awhich is the search area and the headword “have” whose explanation information is displayed, and registered in the keyword registration table84(Step U4), as shown in the second row of PART (c) ofFIG. 3.

When, as shown in PART (a) to PART (c) ofFIG. 10, the user selects the comment input (Step U1; NO, Step U8; YES), selects a keyword “eat” from a list of keywords which are correlated with the headword “have” and registered in the keyword registration table84, the headword “have” whose explanation information is displayed (Step U10), and inputs a comment “since apparently being related to ‘have’, . . . ”, the comment which is to be attached, on the sub-display11by handwriting (Step U11), the inputted comment “since apparently being related to ‘have’, . . . ” is correlated with the selected keyword “eat”, the title “English to Japanese dictionary” of the dictionary database820a, and the headword “have”, and registered in the keyword registration table84(Step U12).

When the user selects the Japanese keyword input (Step U1; YES, Step U5; YES) and inputs a Japanese keyword(tsukamu))” on the touch panel110of the sub-display11by handwriting (Step U3) after the user re-selects the dictionary database820aof the English to Japanese dictionary as the search area (Step S2; YES) and the explanation information of the headword “have” is displayed on the main-display10(Step T13) in the same way described above, the inputted keyword(tsukamu))” and its language type “Japanese” are correlated with the title “English to Japanese dictionary” of the dictionary database820aand the headword “have”, and registered in the keyword registration table84(Step U4).

When the user re-selects the Japanese keyword input (Step U2; YES), the input screen including the input frame for inputting an English search string is displayed on the main-display10(Step T1) as shown in PART (a) ofFIG. 11. In addition, the input frame for inputting a Japanese search string is displayed in the input screen (Step T3) by being judged that a Japanese keyword(tsukamu))” is correlated with the dictionary database820aof the English to Japanese dictionary and registered in the keyword registration table84(Step T2; YES).

When the user selects the input frame for inputting a Japanese search string, and selects the headword retrieval in Japanese (Step T30; YES), a Japanese search string can be inputted into the selected input frame (Step T31).

In the state shown in PART (b) ofFIG. 11, when the user does not select the input frame for a Japanese search string but selects the input frame for inputting an English search string (Step T4; YES), and inputs an English search string “eat” therein (Step T5), headwords “eat”, “eatable”, and the like corresponding to the search string “eat” are retrieved from the dictionary database820aof the English to Japanese dictionary. In addition, a headword “have” correlated with a keyword “eat” corresponding to the search string “eat”, shown in the second row of PART (c) ofFIG. 3, is retrieved from headwords registered in the keyword registration table84(Step T7) by being judged that there is an English keyword which is correlated with the dictionary database820aof the English to Japanese dictionary and registered in the keyword registration table84(Step T6; YES).

As shown in PART (c) ofFIG. 11, the retrieved headwords “eat”, “eatable”, “have”, and the like are displayed as a headword list on the main-display10(Step T8). More specifically, the headword “eat” which completely agrees with the search string is displayed at the top of the headword list among the headwords “eat”, “eatable”, and the like retrieved from the dictionary database820aof the English to Japanese dictionary, and the headword “have” retrieved from the keyword registration table84is displayed immediately under the headword “eat”, which completely agrees with the search string, in the headword list. In addition, at the time, the headword “have” retrieved from the keyword registration table84is displayed in boldface type so as to be distinguishable in the headword list.

When the user specifies the headword “have” in the headword list through the cursor keys2e(Step T9; YES), the comment “since apparently being related to ‘have’, . . . ” which is correlated with the specified headword “have” and registered in the keyword registration table84is displayed on the sub-display11(Step T11).

As shown in PART (a) ofFIG. 12, when the user selects the Japanese-related dictionaries (dictionaries which are retrievable in Japanese such as the dictionary database820bof “Ko*en” (Japanese dictionary) and the dictionary database820cof “Mei* Japanese Dictionary”) as the search area at the time (Step S4; YES), and inputs a Japanese search string(tsukamu))” (Step V5), it is judged that a Japanese keyword(tsukamu))” is correlated with the dictionary database820aof the English to Japanese dictionary of the dictionary/encyclopedia database set82, and registered in the keyword registration table84(Step V6; YES).

Next, headwords(tsukamu))” and the like corresponding to the search string(tsukamu))” are retrieved from each of the dictionaries which are retrievable in Japanese such as the dictionary databases820band820c. In addition, a headword “have” correlated with a keyword(tsukamu))” which corresponds to the search string(tsukamu))” is retrieved from among headwords registered in the keyword registration table84(Step V7) as shown in the third row of PART (c) ofFIG. 3.

Then, as shown in PART (b) ofFIG. 12, the retrieved headwords(tsukamu))”, “have”, and the like are displayed as a headword list on the main-display10(Step V8). More specifically, the headwords(tsukamu))” and the like retrieved from the dictionary databases820are correlated with the title of each of the databases820from which each of the headwords is retrieved so as to be displayed, the displayed title being “Ko*en” or “Mei*” as shown in PART (b) ofFIG. 12. Also, the headword “have” retrieved from the keyword registration table84is correlated with the title of the dictionary which is correlated with the headword “have” and registered in the key registration table84so as to be displayed, the displayed title being “E to J” as shown in PART (b) ofFIG. 12. At the time, the headword(tsukamu)” which completely agrees with the search string is displayed at the top of the headword list among the headwords(tsukamu)” and the like retrieved from the dictionary databases820band820cof the Japanese dictionaries, and the headword “have” retrieved from the keyword registration table84is displayed immediately under the headword(tsukamu)”, which completely agrees with the search string, in the headword list. In addition, at the time, the headword “have” retrieved from the keyword registration table84is displayed in boldface type so as to be distinguishable in the headword list.

Second Embodiment of Operation

First, as shown in PART (a) ofFIG. 13, when a user selects the encyclopedia database820dof the ceremonial occasion encyclopedia as the search area (Step S6; YES), the category selection screen for selecting a large category from among large categories including “coming-of-age” and “marriage” is displayed on the main-display10(Step W1).

When the user selects a large category “manner” through the category selection screen (Step W6; YES), medium categories “basic rules of etiquette” and the like of the selected large category “manner” are displayed on the main-display10in a list form (Step W7). When the user selects the medium category “basic rules of etiquette”, small categories(about posture)” and the like of the selected medium category “basic rules of etiquette” are displayed on the main display10as shown in PART (b) ofFIG. 13.

When the user selects the small category(about posture)” (Step W8), the explanation information of the selected small category(about posture)” is read from the encyclopedia database820d, and displayed on the main-display10(Step W9) as shown in PART (c) ofFIG. 13. At the time, the keyword registration button111is displayed on the sub-display11.

When, as shown in PART (d) and PART (e) ofFIG. 13, the user selects the Japanese keyword input (Step U1; YES, Step U5; YES), and inputs a Japanese keyword; shisei)” on the touch panel110of the sub-display11by handwriting (Step U6), the inputted keyword; shisei)” and its language type “Japanese” are correlated with the title “ceremonial occasion encyclopedia” of the encyclopedia database820d, which is the search area, and the small category(about posture)”, and registered in the keyword registration table84(Step U7), as shown in the fourth row of PART (c) ofFIG. 3.

When, as shown in PART (a) to PART (c) ofFIG. 14, the user selects the comment input (Step U1; NO, Step U8; YES), selects the keyword; shisei)” from a list of keywords which are correlated with the small category(about posture)” and registered in the keyword registration table84, the small category whose explanation information is displayed (Step U10), and inputs a comment “by; shisei)’, manner of posture can . . . ”, the comment which is to be attached, on the sub-display11by handwriting (Step U11), the inputted comment “by; shisei)’, manner of posture can . . . ” is correlated with the selected keyword; shisei)”, the title “ceremonial occasion encyclopedia” of the encyclopedia database820d, and the small category(about posture)”, and registered in the keyword registration table84(Step U12).

As shown in PART (a) ofFIG. 15, when the user selects the Japanese-related dictionaries as the search area (Step S4; YES), and inputs a Japanese search string; shisei)” (Step V5), it is judged that a Japanese keyword; shisei)” is correlated with the encyclopedia database820dof the dictionary/encyclopedia database set82, and registered in the keyword registration table84(Step V6; YES).

Next, headwords; shisei)” and the like corresponding to the search string; shisei)” are retrieved from each of the Japanese-related dictionaries such as the dictionary databases820band820c. In addition, a small category(about posture)” correlated with a keyword; shisei)” which corresponds to the search string; shisei)” is retrieved from small categories registered in the keyword registration table84(Step V7) as shown in the fourth row of PART (c) ofFIG. 3.

Then, as shown in PART (b) ofFIG. 15, the retrieved headwords (and small categories); shisei)”,(about posture)”, and the like are displayed as a headword list on the main-display10(Step V8). More specifically, the headwords; shisei)” and the like retrieved from the dictionary databases820are correlated with the title of each of the databases820from which each of the headwords is retrieved so as to be displayed, the displayed title being “Ko*en” or “Mei*” as shown in PART (b) ofFIG. 15. Also, the small category(about posture)” retrieved from the keyword registration table84is correlated with the title of the encyclopedia which is correlated with the small category(about posture)” and registered in the key registration table84so as to be displayed, the displayed title being “Ceremonial Occasion”. At the time, the headwords; shisei)” which completely agree with the search string are displayed at the top of the headword list among the headwords; shisei)” and the like retrieved from the dictionary databases820band820cof the Japanese dictionaries, and the small category(about posture)” retrieved from the keyword registration table84is displayed immediately under the headwords; shisei)”, which completely agrees with the search string, in the headword list. In addition, at the time, the small category(about posture)” retrieved from the keyword registration table84is displayed in boldface type so as to be distinguishable in the headword list.

When the user specifies the small category(about posture)” in the headword list through the cursor keys2e(Step T9; YES), the comment by; shisei)’, manner of posture can . . . ”, which is correlated with the specified small category(about posture)” and registered in the keyword registration table84, is displayed on the sub-display11(Step T11) as shown in PART (c) ofFIG. 15.

When the user re-selects the encyclopedia database820dof the ceremonial occasion encyclopedia as the search area (Step S6; YES), the category selection screen for selecting a large category from large categories including “coming-of-age” and “marriage” is displayed on the main-display10(Step W1) as shown inFIG. 16. At the time, the input frame for inputting a search string in order to retrieve a small category in a language type of Japanese is displayed in the category selection screen (Step W3) by being judged that a Japanese keyword; shisei)” is correlated with the encyclopedia database820dof the ceremonial occasion encyclopedia and registered in the keyword registration table84(Step W2; YES).

When the user selects the input frame for Japanese, and selects category retrieval in Japanese (Step W12; YES), a Japanese search string can be inputted in the selected input frame (Step W13).

Third Embodiment of Operation

In a state where a keyword “have” is correlated with a headword “have” of the dictionary database820aof the English to Japanese dictionary by default and a user adds a keyword “had” to the headword “have”, when the user selects the dictionary database820aof the English to Japanese dictionary as the search area (Step S2; YES) as shown in PART (a) ofFIG. 17, and the explanation information of the headword “have” is read from the dictionary database820aof the English to Japanese dictionary and displayed on the main-display10(Step T13), the keyword registration button111is displayed on the sub-display11.

When the user selects the comment input (Step U1; NO, Step U8; YES), the keywords “have” and “had” which are correlated with the headword “have” and registered in the key registration table84are displayed on the main-display10in a list form, the headword whose explanation information is displayed (Step U9) as shown in PART (b) ofFIG. 17.

When the user selects a keyword from the keywords (Step U10), and inputs a comment to be attached to the headword (Step U11), the inputted comment is correlated with the selected keyword, the title “English to Japanese Dictionary” of the dictionary database820a, and the headword “have”, and registered in the keyword registration table84(Step U12).

By the electronic dictionary1described above, as shown in Steps T7and T8ofFIG. 5, Steps V7and V8ofFIG. 6, PART (c) ofFIG. 11, PART (b) ofFIG. 12, and the like, when headwords corresponding to an inputted search string are retrieved from the dictionary storage unit, the retrieved headwords are displayed as a headword list, and the explanation information of a headword which is selected based on a user operation from among the headwords in the headword list is read from dictionary information and displayed. Then, when a keyword which is inputted based on a user operation is correlated with the headword and registered in the keyword registration table84, the headword whose explanation information is displayed, and the search string is inputted thereafter, the headword correlated with the keyword corresponding to the search string is retrieved from headwords registered in the keyword registration table84, and added to the headword list so as to be displayed. Accordingly, even when what keyword is attached to what headword cannot be remembered, a keyword corresponding to the search string is detected, and a headword correlated with the keyword and registered in the keyword registration table84is retrieved, and added to the headword list to be displayed. As a result, retrieval of a headword to which a keyword is attached can be performed in addition to the standard headword search without being aware that a keyword is attached to a retrieval-target headword. Therefore, retrieval of a headword to which a user attaches a keyword can be performed efficiently.

As shown in Step T8ofFIG. 5, Step V8ofFIG. 6, PART (c) ofFIG. 11, PART (b) ofFIG. 12, and the like, since a headword correlated with a keyword and registered in the keyword registration table84is displayed so as to be distinguishable in a headword list, the headword correlated with a keyword which corresponds to a search string and registered in the keyword registration table84can be distinguished from headwords retrieved from the dictionary databases820. Consequently, a headword correlated with a keyword and registered in the keyword registration table84can be easily selected from a headword list so that the explanation information of the selected headword is displayed. Therefore, retrieval of a headword to which a keyword is attached can be performed more efficiently.

As shown in Step T11ofFIG. 5, Step V11ofFIG. 6, PART (c) ofFIG. 11, and the like, when a headword correlated with a keyword and registered in the keyword registration table84is specified in a headword list by a user operation, a comment correlated with the specified headword and registered in the keyword registration table84is displayed on the sub-display11. Consequently, it can be easily understood why a user attaches a keyword to a headword.

As shown in Step T3ofFIG. 5, PART (a) ofFIG. 11, and the like, an input frame for a language type of headwords stored in a dictionary database820is displayed in the input screen. In addition, when a keyword is registered in a language type which is different from a language type of the headwords stored in the dictionary database820, an input frame for the language type of the keyword is also displayed. Therefore, when a keyword is registered in a language type which is different from a language type of headwords, retrieval of a headword can be performed in the language type of the keyword.

As shown in Steps W3, W5, and W12to W23ofFIG. 7,FIG. 16, and the like, when a keyword is correlated with a category of the encyclopedia database820dand registered in the keyword registration table84, an input frame for the language type of the keyword is displayed on the category selection screen. When a search string is inputted in the input frame of the category selection screen in the language type corresponding to the input frame based on a user operation, retrieval of a category, which is correlated with a keyword corresponding to the search string and registered in the keyword registration table84, from categories registered in the keyword registration table84is performed, and the explanation information of the category is read from the encyclopedia database820dand displayed. Therefore, even in the case of the encyclopedia database820dfrom which a category cannot be retrieved by inputting a search string, retrieval of a category corresponding to a keyword can be performed.

As shown in Step T8ofFIG. 5, Step V8ofFIG. 6, PART (c) ofFIG. 11, PART (b) ofFIG. 12, and the like, a headword which completely agrees with a search string is displayed at the top of a headword list among retrieved headwords, and a headword which is correlated with a keyword corresponding to the search string and registered in the keyword registration table84is displayed immediately under the headword which completely agrees with the search string, in the headword list. Consequently, a headword correlated with a keyword and registered in the keyword registration table84can be easily selected from a headword list so that the explanation information of the selected headword is displayed. Therefore, retrieval of the explanation information of a headword to which a keyword is attached can be performed more efficiently.

The present invention is not limited to the embodiments described above, and can be appropriately modified without departing from the scope of the present invention.

For example, the information display program81in the present invention may be stored in a memory card, a CD, or the like, which is attachable to and removable from the electronic dictionary1.

Furthermore, the various operations performed by a user to the electronic dictionary1may be performed by using other keys which are different from the keys described above.

Japanese Patent Application No. 2009-225736 filed on Sep. 30, 2009, the entire disclosure of which, including the description, claims, drawings, and abstract, is incorporated herein by reference in its entirety.