Abstract:
A cellular phone has back light illumination for its display unit and a key unit, and is capable of receiving internet information, receiving karaoke songs, or receiving and sending electronic mails. In the case that the cellular phone is used for electronic mailing, it is checked whether the cellular phone is operated in a character/number input mode. If it is not in the input mode, only the display unit and a function key part of the key unit are illuminated. A ten key part of the key unit is illuminated only when it is to be manipulated to change display on the display unit. In the case of executing the internet function or the karaoke function, the illumination control for the display unit and the key unit is controlled in the similar manner.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application relates to and incorporates herein by reference Japanese Patent Applications No. 11-199253 filed on Jul. 13, 1999 and 2000-106997 filed on Apr. 7, 2000. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to a portable terminal device such as a cellular phone having illumination function for a key unit and a display unit. 
     Conventional cellular phones have respective key units and LCD display units on the front side. The key unit includes a plurality of keys for inputting numbers, characters, operation commands and the like. The display unit is for displaying various information in characters or in images. The key unit and the display unit also include backlights such as light-emitting diodes so that the key unit and the display unit may be illuminated in operation. The light emitting diodes are turned off after a predetermined time, e.g., 10 seconds, from the completion of operation of the key unit and the display unit thereby to save the energy of a built-in battery. 
     The cellular phone may have a character information display mode for displaying character information for electronic mails or bank account checking on its display unit. In this mode, the keys are operated frequently. If illumination control of the key unit and the display unit is effected simultaneously based on only the phone condition or the time lapse after completing phone operation, battery power consumption increases. 
     It is proposed in JP-A-11-154900 to enable manual predetermined setting of turning of f of either the display unit or the key unit. However, if turning off the key unit is set in advance, it becomes difficult to manipulate the keys in the darkness. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide a portable terminal device with illumination control which consumes less electric power. 
     According to the present invention, a portable terminal device such as a cellular phone comprises a key unit, a display unit, an illumination unit, and a light control circuit. The illumination unit first illuminates both the display unit and the key unit, but stops illuminating the key unit based on a display condition of the display unit to save power supplied by a built-in battery. 
     In an internet mode, the illumination of the key unit is stopped after a predetermined time, and the illumination of the display unit is maintained as long as the displayed information on the display unit is changing. 
     In a karaoke mode, the illumination of the key unit is stopped after a predetermined time, and the illumination of the display unit is maintained as long as music is produced, for instance, song words are displayed on the display unit. 
     In an electronic mail mode, the illumination of ten key part of the key unit is stopped when the terminal device is in a non-character/number input mode in a predetermined time, and illumination of the display unit and a function key part of the key unit is maintained in a character/number input mode in the predetermined time. 
    
    
     BACKGROUND OF THE INVENTION 
     Other features, objects and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings. 
     In the drawings: 
     FIG. 1 is a front view of a cellular phone to which the present invention is applied; 
     FIG. 2 is a block diagram showing an electronic circuit unit construction of the cellular phone shown in FIG. 1; 
     FIG. 3 is a flow diagram showing illumination control processing executed in the case of internet connection mode in a first embodiment of the present invention; 
     FIGS. 4A to  4 D are schematic views showing displays of the cellular phone in the first embodiment; 
     FIG. 5 is a flow diagram showing karaoke processing executed by the cellular phone in a second embodiment of the present invention; 
     FIG. 6 is a flow diagram showing an illumination control mode in the case of karaoke mode in the second embodiment; 
     FIG. 7 is an electric wiring diagram showing a part of the electronic circuit unit according to a third embodiment of the present invention; 
     FIG. 8 is a flow diagram showing illumination control processing executed in the third embodiment; 
     FIGS. 9A to  9 G are schematic views showing displays at the time of an electronic mailing mode in the third embodiment. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring first to FIG. 1, a cellular phone as a portable terminal device comprises a casing  10 , a key unit  20 , display unit  30  and a touch sensor unit  40 . The key unit  20  is provided on the front lower side of the casing  10 , and includes function key part  20 A and a ten key part  20 B. 
     The function key part  20 A includes an arrow key  20   a , a FIX key  20   b  and the like, and the ten key part  20 B includes number/character keys. The display unit  30  uses a liquid crystal display panel, and is fit in the opening  12  formed on the front upper side of the casing  10  to display various information. The touch sensor unit  40  includes a pair of touch sensors  41  and  42  provided at the left and right lower sides  13   a  and  13   b  of the casing  10 . The touch sensor unit  40  detects user&#39;s manipulation operation of the cellular phone, when both sensors  41  and  42  are manipulated. 
     The cellular phone also comprises an electronic circuit unit shown in FIG.  2 . The electronic circuit unit includes a microphone  50 , a speaker  51 , an audio circuit  52 , a radio signal processing circuit  53 , an antenna  54 , a memory unit  55 , a display light control circuit  56 , a key light control circuit  57 , a secondary battery  58 , and a microcomputer  59 . 
     The microphone  50  converts the phone user&#39;s input voice sounds to audio signals and applies the audio signals to the audio circuit  52  which is controlled by the microcomputer  52 . The audio circuit  52  responsively produces transmission signals, and the radio signal circuit  53  which is also controlled by the microcomputer  59  modulates the transmission signals. Thus, the modulated signals are transmitted from the antenna  54  to a base station (not shown). 
     The radio signal circuit  53  in turn receives modulated signals from the base station through the antenna  54 , and applies demodulated signals to the audio circuit  52 . The speaker  51  responsively produces output voice sounds in response to the demodulated signals from the audio circuit  52 . 
     The display light control circuit  56  controlled by the microcomputer  59  drives a plurality of light emitting diodes (for instance, light emitting diodes  7   a  and  7   b  in FIG. 7) provided as a back light exclusive to the display unit  30 . The key light control circuit  57  controlled by the microcomputer  59  drives a plurality of light emitting diodes (for instance, light emitting diodes  7   c  to  7   f  in FIG. 7) provided as a back light exclusive to the key unit  20 . 
     The secondary battery  58  supplies an electric power to the above circuits. The microcomputer  59  executes various processing such as a call transmitting and receiving processing, internet processing, karaoke processing, illumination control processing, and the like in the following manner based on a program and data stored in the memory unit  55 . 
     First Embodiment 
     In a first embodiment, the microcomputer  59  is programmed to execute the illumination control processing as shown in FIG.  3 . This processing is executed every predetermined time as an interrupt routine in the course of execution of the internet processing. 
     The microcomputer  59  first checks at step  200  whether the key unit  20  is manipulated. If the key unit  20  is manipulated (YES at step  200 ), the microcomputer  59  drives the display light control circuit  56  and the key light control circuit  57  at step  210 . Thus, both the display unit  30  and the key unit  20  are illuminated. 
     The microcomputer  59  checks at step  220  whether a predetermined time T 1  has lapsed from the start of illuminating the display unit  30  and the key unit  20 . If the predetermined time T 1  has lapsed (YES at step  220 ), the microcomputer  59  checks whether the display on the display unit  30  is changing. The microcomputer  59  determines the display change, if a display change flag stored in the memory unit  55  is in the set condition. If the display is changing (YES at step  230 ) after the manipulation of the key unit  20 , the microcomputer  59  instructs the key light control circuit  57  to turn off the illumination of the key unit  20  at step  240  thereby saving the electric power of the secondary battery  58 . However, the illumination of the display unit  30  by the display light control circuit  57  is continued, because the display is changing. 
     The microcomputer  59  checks at step  250  whether the display change ceased. If the display change ceased, that is, the display change flag in the memory unit  55  is in the reset condition (YES at step  250 ), the microcomputer  59  instructs the display light control circuit  56  to turn off the illumination of the display unit  30  at step  260 . The illumination of the display unit  30  may be turned off after a predetermined time T 2 . 
     If no display change occurs (NO at step  230 ), on the other hand, the microcomputer  59  instructs both the display light control circuit  56  and the key light control circuit  57  to turn off both illumination of the key unit  20  and the display unit  30  at step  290 . 
     The microcomputer  59  then checks at step  270  whether the touch sensor unit  40  is manipulated. If the touch sensor output changes from OFF to ON indicating the manipulation of the touch sensor unit  40  (YES at step  270 ), the microprocessor  59  repeats the above processing again from step  210  so that the key unit  20  and the display unit  30  are both illumination again. 
     If the touch sensor unit  40  is not manipulated (NO at step  270 ), the microcomputer  59  further checks at step  280  whether the key unit  20  is manipulated. If the key unit output changes from OFF to ON indicating the manipulation of the key unit  20  (YES at step  280 ), the microcomputer  59  repeats the above processing from step  210  so that the key unit and the display unit  30  are illuminated again. If neither the touch sensor unit  40  nor the key unit  20  is manipulated (NO at steps  270  and  280 ), the illumination for both the key unit  20  and the display unit  30  is maintained turned off. 
     The illumination light control for the key unit  20  and the display unit  30  performed by the above processing (FIG. 3) is shown in FIGS. 4A to  4 D with respect to the case in which news information is browsed through the internet by downloading internet information and displaying news menu. 
     When the key unit  20  is manipulated in the predetermined manner, the cellular phone starts receiving news data from a server side (base station) through the internet. The display unit  30  alternately displays two information as shown in FIG. 4A, while the news data are being received. In this instance, both the key unit  20  and the display unit  30  are illuminated, and a cartoon character image  30   a  displayed in the middle of the display unit  30  changes. The program for changing the cartoon character image  30   a  as shown in FIG. 4A is stored in the memory unit  55  as a part of internet function processing. 
     If the news data are still being received at the time of a lapse of the predetermined time T 1 , the cartoon character image  30   a  continues to change alternately with the illumination of the display unit  30  being maintained as shown in FIG.  4 B. However, the illumination of the key unit  20  is turned off in this instance. 
     When receiving the news data is completed, the change of the cartoon character image  30   a  is stopped and the display change flag is reset. The illumination of the display unit  30  is turned off after the predetermined time T 2 . The display unit  30  displays the menu of the news as shown in FIG.  4 C. If the touch sensor unit  40  is manipulated, both the key unit  20  and the display unit  30  are illuminated again as shown in FIG.  4 D. 
     In the above operation, the key unit  20  need not be manipulated as long as the news data is being received for browsing internet news. The key unit  20  and the display unit  30  are continued to be illuminated for the predetermined time T 1  from starting receiving the news data. However, the illumination of the key unit  20  is turned off, while the illumination of the display unit  30  is maintained until the display change stops. Thus, the electric power consumption can be reduced by turning off the illumination for the key unit  20  at an earliest possible time. 
     The power saving is very advantageous particularly when the information receiving operation continues for a long time without requiring manipulation of the key unit  20 . Further, it is advantageous particularly when the display unit  30  uses a color liquid crystal panel, because the color liquid crystal panel consumes more power. The electric power consumption is reduced further, because the illumination of the display unit  30  is also turned off when the predetermined time T 2  lapses after completing receiving the information. 
     In addition to the advantage of power saving, the illumination of the key unit  20  and the display unit  30  is restored by manipulation of the touch sensor unit  40  or the key unit  20  even after the illumination of the key unit  20  and the display unit  30  is turned off, so that the cellular phone can be manipulated with ease even in the darkness. 
     The first embodiment may be so modified that the illumination of both the key unit  20  and the display unit  30  is turned off after the internet information has completely been received. In this instance, the display on the display unit  30 , for instance, character images or pictures, may be changed after the completion of the information and turning off the illumination may be triggered by monitoring changes of the display. 
     The display change may be effected not only for the internet information but also for other display information so that the illumination control may be effected by monitoring the changes. The illumination of the key unit  20  may be turned off in the course of receiving information (downloading) without maintaining the illumination of the key unit  20  for the predetermined time T 1 . 
     Second Embodiment 
     In a second embodiment, the illumination control is effected in the course of karaoke processing which is shown in FIG.  5 . In the second embodiment, the memory unit  55  stores a flag KA indicative of karaoke function. Further, the memory unit  55  stores music data which includes both orchestral sound data and song words data. The music data may be received through the internet. 
     The microcomputer  59  executes the karaoke processing when the key unit  20  is manipulated in the predetermined manner to select and receive the music data. The microcomputer  59  first sets the karaoke flag KA (KA=1) at step  300 , and reads out the karaoke sound data from the memory unit  55  at step  310 . The microcomputer  59  drives the audio circuit  52  based on the sound data so that the orchestral sound may be output from the speaker  51  at step  320 . The microcomputer  59  also drives the display unit  30  based on the words data so that the display unit  30  displays the song words in timed relation with the sound output at step  330 . In the karaoke processing, the phone user&#39;s singing voice may be detected by the microphone  50  and produced from the speaker  51  together with the orchestral sound. 
     The microcomputer  59  checks at step  340  whether the karaoke song has ended. If the song is still produced (NO at step  340 ), the microcomputer  59  executes the above processing from step  310 . If the song has ended (YES at step  340 ), the microcomputer  59  resets the karaoke flag KA (KA=0) at step  350 , thus completing the karaoke processing. 
     In the second embodiment, the illumination control is executed as shown in FIG. 6 in place of the processing of the first embodiment shown in FIG.  3 . In FIG. 6, steps  210 ,  220  and  260  are the same as steps  210 ,  220  and  260  of FIG.  3 . This processing is executed every predetermined time as an interrupt to the karaoke processing. 
     The microcomputer  59  starts illuminating the display unit  30  and the key unit  20  at step  210  by the display light control circuit  56  and the key light control circuit  57 , respectively. The microcomputer  59  checks at step  220  whether the predetermined time T 1  has lapsed from starting the illumination. If the predetermined time has lapsed (YES at step  220 ), the microcomputer  59  instructs the key light control circuit  57  to turn off the illumination of the key unit  20  at step  221 , while still maintaining the illumination of the display unit  30 . This turning off may be effected after a predetermined time from a display of the song words on the display unit  30 . 
     The microcomputer  59  then checks at step  223  whether it is the end of the song with reference to the karaoke flag KA stored in the memory unit  55 . If the flag KA is in the set condition indicating that the orchestral sound is still being produced (NO at step  223 ), the microcomputer  59  executes steps  224  and  225  to check whether the touch sensor  224  or key unit  20  is manipulated, respectively, so that the illumination of the key unit  20  and the display unit  30  may be controlled in the same manner as at steps  270  and  280  in the first embodiment shown in FIG.  3 . However, if the flag KA is in the reset condition indicating the end of the song (YES at step  260 ), the microcomputer  59  instructs the display light control circuit  56  to turn off the illumination of the display unit  30  at step  260 . The illumination of the display unit  30  is turned off after the predetermined time T 2  as in the first embodiment. 
     In the second embodiment, the display unit  30  may be illuminated in timed relation with the display of the song words in place of the above timed relation with the production of the orchestral sound. 
     According to the second embodiment, the illumination of the key unit  20  is limited to the predetermined time T 1  while the illumination of the display unit  30  is maintained as long as the song words are displayed on the display unit  30 . Thus, the power for illuminating the key unit  20  is saved while ensuring visibility of the song words on the display unit  30 . 
     Third Embodiment 
     In a third embodiment, a pair of light emitting diodes  7   a  and  7   b  are provided between the display unit  30  and an uppermost key part (function key part  20 A including the arrow key  20   a  and the FIX key  20   b ) of the key unit  20  to illuminate both the display unit  30  and the function key part  20 A of the key unit  20 . The diodes  7   a  and  7   b  are connected in parallel between a power supply and a transistor  1  which is controlled by the microcomputer  59 . The transistor  1  operates as the display light control circuit  56 . 
     Another set of light emitting diodes  7   c  to  7   f  are provided in the middle and lowermost part (ten key part  20 B including ten ( 0  to  9 ) keys) of the key unit  20  to illuminate the ten key part  20 B. The diodes  7   c  to  7   f  are connected in parallel between the power supply and a transistor  2  which is controlled by the microcomputer  59 . The transistor  2  operates as the key light control circuit  57 . 
     The microcomputer  59  executes the illumination control processing shown in FIG. 8 every predetermined time (less than 10 seconds) as an interrupt in the course of other processing such as electronic mailing. 
     Referring to FIG. 8, the microcomputer  59  reads out the present condition of the cellular phone from the memory unit  55  at step  400 , and checks at step  410  whether it is in the wait condition with reference to the stored present condition. If the cellular phone is not in the wait condition (NO at step  410 ), the microcomputer  59  checks at step  420  whether a predetermined time T 0  (for instance, 10 seconds) has lapsed from the last manipulation of the keys. 
     If the lapsed time is less than the predetermined time T 0  (NO at step  420 ), the microcomputer  59  checks at step  450  whether it is in the character/number input mode. This check may be made with reference to a character/number input flag stored in the memory unit  55 . 
     If the input flag is set indicating the character/number input mode (YES at step  450 ), the microcomputer  59  turns on the transistors  1  and  2  at steps  460  and  461  to illuminate the display unit  30  and the key unit  20  by the light emitting diodes  7   a  to  7   f , respectively. If the input flag is reset (NO at step  450 ), the microcomputer  59  turns on the transistor  1  at step  470  to illuminate mostly the display unit  30  and the function key part  20 A of the key unit  20  by the light emitting diodes  7   a  and  7   b . However, it turns off the transistor  2  at step  471  so that the ten key part  20 B of the key unit  20  is not illuminated by the light emitting diodes  7   c  to  7   f.    
     Further, if the cellular phone is in the wait condition (YES at step  410 ) or the predetermined time T 0  has lapsed after the last key manipulation (YES at step  420 ), the microcomputer  59  turns off both transistors  1  and  2  so that the display unit  30  and the key unit  20  are not illuminated. 
     An exemplary operation of the third embodiment is shown in FIGS. 9A to  9 G. In this instance, the display at the time of the electronic mailing is shown as a character information mode. 
     When the FIX key  20   b  of the function key part  20 B in the key unit  20  is manipulated, the display unit  30  displays a menu screen as shown in FIG. 9A as a part of the character information mode. In this instance, the character input flag in the memory unit  55  is in the reset condition. As a result, the display unit  30  and the function key part  20 A of the key unit  20  are illuminated by the light emitting diodes  7   a  and  7   b , while the ten key part  20 B of the key unit  20  is not illuminated. 
     After inverting the display contrast of “GENERATE MAIL” on the display unit  30  by manipulating the arrow key  20   a  (for instance,  7 ), the FIX key  20   b  is manipulated to select “GENERATE MAIL”, that is, electronic mail transmission mode, of the displayed menu. Then the arrow key  20   a  is manipulated again to scroll the display screen so that mail address position selection screen appears on the display unit  30 . When the FIX key  20   b  is manipulated again, the mail address input screen is fixedly displayed on the display unit  30  as shown in FIG. 9B so that character/number input mode is executed. At this time, the character input flag is set in the memory unit  55 , and the ten key part  20 B is also illuminated by the light emitting diodes  7   c  to  7   f.    
     When the ten keys are manipulated to input the mail address as shown in FIG. 9C, the display unit  30  displays the input address. When the FIX key  20   b  is then manipulated, the character input flag in the memory unit  55  is reset so that the illumination for the ten key part  20 B is stopped. 
     Then, after manipulating the FIX key  20   b , the arrow key  20   b  is manipulated to further scroll the display screen so that a mail message text input selection screen appears on the display unit  30 . If the FIX key  20   b  is manipulated, the mail message text input screen is fixedly displayed as shown in FIG. 9D so that the mail message (character/number) input mode is executed. At this time, the character input flag is set in the memory unit  55 , and the ten key part  20 B is also illuminated again. 
     As the mail message is input by manipulation of the ten key part  20 B, the display unit  30  displays the input mail message as shown in FIG.  9 E. If the FIX key  20   b  is manipulated after the message input, the input mail is fixed as shown in FIG.  9 F and the character input flag in the memory unit  55  is reset. Thus, the illumination for the ten key part  20 B is stopped. 
     Then, the arrow key  20   a  is manipulated again to scroll the display screen so that a mail transmission (SEND) screen appears on the display unit  30 . When the FIX key  20   b  is manipulated again, the mail is transmitted or sent out, and the display unit  30  displays SEND screen as shown in FIG.  9 G. Thus, the electronic mailing processing ends. The illumination of the display unit  30  and the function key part  20 A is finally stopped after 10 seconds from the last manipulation of the FIX key  20   b.    
     According to the third embodiment, the ten key part  20 B is illuminated only in the character/number input mode is executed, while the display unit  30  and the function key part  20 A are illuminated continuously as long as the display unit  30  is displaying information. Thus, the electric power of the secondary battery  58  is saved. 
     The present invention should not be limited to the above embodiments, but may be implemented in many other ways. For instance, the portable terminal device may be a personal handy phone (PHS) or portable computer. The display unit may be a color liquid crystal display or other than a liquid crystal panel as long as illumination therefor is required.