Patent Publication Number: US-2007120808-A1

Title: Display unit and portable device provided with the same

Description:
This application claims priority to prior application JP 2005-153576, the disclosure of which is incorporated herein by reference.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a color display unit provided with a plurality of illuminants mutually differing in luminous colors, and a portable device provided with the same.  
      2. Description of the Related Art  
      A display unit for displaying a character and an image has widely been mounted on an electronic equipment.  FIG. 1  is a block diagram illustrating a conventional liquid crystal display unit. As shown in  FIG. 1 , a liquid crystal display unit  401  contains an LCD (Liquid Crystal Display) panel  402  for displaying an image. A backlight  403  for providing the LCD panel  402  with a light is provided behind the LCD panel  402 . The LCD panel  402  is provided with a display section  404  for displaying the image, a scanning line drive circuit  405  for sequentially scanning a scanning line arranged on the display section  404 , and an LCD drive circuit  406  for applying a data signal to a data line arranged on the display section  404 . The backlight  403  contains a white LED (Light Emitting Diode)  407  and a light guide plate (not illustrated). The white LED  407  emits a white light upon receiving an electric current signal from outside, while the light guide plate emits the white light in a planar form toward the LCD panel  402 . adjustment circuit  208  is comprised of a variable resistor VR 2  and a rectifier diode D 2 , while the adjustment circuit  209  is comprised of a variable resistor VR 3  and a rectifier diode D 3 . By adjusting the variable resistors VR 2  and VR 3 , it is possible to control the emission intensity of the green LED  202  and the blue LED  203 , respectively. In this backlight, by adjusting the electric currents being applied to the LEDs  201  through  203  including each color it is possible to adjust the color at the time of displaying the white color.  
      However, in the backlight as shown in  FIG. 2 , when it is desired to have set a white color once by adjusting the variable resistors and subsequently to display the white color including a different color, it is necessary to adjust the variable resistors again. Also, when it is desired to get back to the initial color, it is necessary to adjust the variable resistors again. For this reason, there is a problem that the color of the white color display cannot easily be adjusted.  
      As a technique for solving the problem, other backlight is disclosed in Patent Document 1.  FIG. 3  is a block diagram illustrating another backlight. As shown in  FIG. 3 , the backlight is different from the one as shown in  FIG. 2  in the following points. First, the backlight as shown in  FIG. 3  is not provided with the adjustment circuits  207  through  209  (refer to  FIG. 2 ). Additionally, a DAC (Digital-Analog Converter)  221  is provided in the drive circuit  204  in addition to the transistor T 1  and the fixed resistor R 1 . An analog output signal of the DAC  221  is inputted into a gate of the transistor T 1  via a buffer  224 . Similarly, the drive circuit  205  is provided with a DAC  222  and a buffer  225 , while the drive circuit  206  is provided with a DAC  223  and a buffer  226 .  
      A microcomputer chip  230  for inputting digital signals to the DACs  221  through  223 , respectively is provided, and the microcomputer chip  230  is provided with a storage circuit  230 M. Further, photodetectors PD 1 , PD 2 , and PD 3  for detecting the lights outputted from the LEDs  201 ,  202  and  203 , respectively, are provided and the results of detection of the photodetectors PD 1  through PD 3  are inputted into the microcomputer chip  230 . The configuration other than the described above in this backlight is similar to that of the backlight as shown in  FIG. 2 .  
      In this backlight, the photodetectors PD 1  through PD 3  detect the emission intensities of the LEDs  201  through  203 . Based on these results of detection, the microcomputer chip  230  controls the electric currents being applied to the LEDs  201  through  203  with reference to information stored in the memory circuit  230 M. Thus, it is possible to easily and accurately adjust the color at the time of displaying the white color.  
       FIG. 4  is a block diagram illustrating a mobile phone disclosed in Patent Document 2. As shown in  FIG. 4 , a mobile phone  301  includes an LCD  302  for displaying an image and an LCD backlight for providing the LCD  302  with a light. The LCD backlight  303  includes LEDs (not illustrated) having each color of R, G, and B. The mobile phone  301  also includes a control section  304  for controlling the LCD  302  and the LCD backlight  303 .  
      The control section  304  includes a CPU (Central Processing Unit)  305 , an ROM (Read-Only Memory)  306 , and an RAM (Random Access Memory)  307 , that are connected to the CPU  305 . The control section  304  also includes an RGB drive IC (Integrated Circuit)  308  for driving the LCD backlight  303  based on a control signal from the CPU  305 , and a peripheral IC  309  connected to the CPU  305 . Outside the control section  304 , there are provided a keypad  310  for inputting information to the peripheral IC  309 , and an external I/O  311  to be used for connection with outside.  
      In the mobile phone  301 , electric current setting values for driving the LEDs having each color of R, G, and B of the LCD backlight  303  are stored in the ROM  306 . When a user selects the electric current setting value stored in the ROM  306  by means of operating the keypad  310 , the CPU  305  controls the RGB drive IC  308  based on the electric current setting value, and thereby adjusting the color at the time of displaying the LCD backlight  303  in white color. Thus, the user of the mobile phone  301  can easily display a desired color of the white color on the LCD  302 .  
      The above-mentioned conventional technique, however, has problems as described hereinbelow.  
      The backlight as shown in  FIG. 3  requires a number of signal lines for inputting digital signals to the DACs  221  through  223  of the drive circuits  204  through  206 . Moreover, although not shown in  FIG. 3 , the liquid crystal display unit including the backlight is also provided with signal lines for transmitting an LCD image signal and an LCD control signal. For this reason, a circuit area required for arranging the signal lines becomes wide, resulting in an increase in size of the liquid crystal display unit. Moreover, if trying to prevent an increase in size, a narrow-pitch or multilayered circuit board is consequently required, resulting in an increase in cost of the unit.  
      The mobile phone as shown in  FIG. 4  has similar problems. As shown in  FIG. 4 , electric current setting value data for the LCD backlight  303  is outputted from the CPU  305  to the RGB drive IC  308 . The LCD image signal is also outputted from the CPU  305  to the peripheral IC  309 . The electric current setting value data and the LCD image signal require a number of signal lines for transmission. For this reason, the circuit area required for arranging the signal lines becomes wide, resulting in an increase in size and cost of the unit.  
     SUMMARY OF THE INVENTION  
      The present invention is made in view of the above-mentioned problems, and aims to provide a display unit having fewer number of signal lines and a portable device including the same, in a display unit capable of performing color display.  
      A display unit according to the present invention comprises a plurality of illuminants mutually differing in luminous colors, a drive section for driving the illuminants, a display panel for displaying an image by being illuminated from the illuminants, a control section for controlling the drive section and the display panel. According to an aspect of the present invention, the display unit further comprises a common signal line for transmitting a first signal constituting at least a part of signals that the control section outputs to the drive section, and a second signal constituting at least a part of signals that the control section outputs to the display panel.  
      In the present invention, transmitting the first signal and the second signal via the common signal line makes it possible to decrease the number of the signal lines.  
      In the display unit according to the present invention, it may be that the common signal line transmits the first signal and the second signal in a time-division format and that both the first signal and the second signal are arranged within one frame.  
      Further, it may be that the first signal is electric power data for representing the magnitude of electric power wherein the drive section supplies to each of the illuminants, and that the second signal is image data for representing the image-displayed on the display panel.  
      In this case, the display unit still further comprises other common signal line for transmitting a third signal constituting at least a part of signals excluding the first signal out of signals that the control section outputs to the drive section and a fourth signal constituting at least a part of signals excluding the second signal out of signals that the control section outputs to the display panel. Thus, the number of the signal lines can be further decreased.  
      Furthermore, it is desirable that the control section generates the first signal based on input information inputted from outside and thereby adjusts an emission intensity of the each illuminant. Thus, a user can set the emission intensity of each illuminant.  
      It is desirable that the display unit further comprises a storage section for storing the electric power data and that the control section reads the electric power data from the storage section based on the input information, and thereby generates the first signal. Thus, the emission intensity of each illuminant can be easily adjusted.  
      It may be that the control section adjusts a color of white color display of the display panel by adjusting the emission intensity. In this case, the input information may relate to a color temperature of the white color display, and the input information may relate to the emission intensity of the each illuminant. Alternatively, the input information may relate to the emission intensity of the each illuminant. Thus, it is possible to correspond to preferences of colors that are different depending on regions.  
      It may be that the control section adjusts the brightness of the display panel by adjusting said emission intensity.  
      According to another aspect of the present invention, the display unit may comprise a common signal line for transmitting a first signal which constitutes at least a part of signals that said control section outputs to said drive section and which is electric power data for representing the magnitude of electric power that said drive section supplies to each of said illuminants, and a fourth signal which constitutes at least a part of signals that said control section outputs to said display panel and which is a control signal for controlling a drive circuit provided in said display panel.  
      According to still another aspect of the present invention, a portable device comprising the above-mentioned display unit is provided.  
      According to yet another aspect of the present invention, a portable device comprising the above-mentioned display unit and a GPS device is provided. In this case, the portable device obtains information for representing the region through the GPS device.  
      According to yet another aspect of the present invention, a portable device comprising the above-mentioned display unit is provided. The portable device obtains information for representing the region from international roaming information.  
      According to the present invention, in the display unit capable of performing the color display, it is possible to decrease the number of the signal lines by transmitting the first and second signals via the common signal line. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a block diagram illustrating a conventional liquid crystal display unit;  
       FIG. 2  is a circuit diagram illustrating a backlight of a liquid crystal display unit as disclosed in Patent Document 1;  
       FIG. 3  is a block diagram illustrating other backlight as disclosed in Patent Document 1;  
       FIG. 4  is a block diagram illustrating a mobile phone as disclosed in Patent Document 2;  
       FIG. 5  is a block diagram illustrating a liquid crystal display unit according to a first embodiment of the present invention;  
       FIG. 6  is a block diagram illustrating a configuration of a control section as shown in  FIG. 5 ;  
       FIG. 7  is a diagram illustrating a composite data signal outputted from the control section as shown in  FIG. 5 ;  
       FIG. 8  is a block diagram illustrating a configuration of a backlight drive section as shown in  FIG. 5 ;  
       FIG. 9  is a block diagram illustrating a configuration of an LCD module as shown in  FIG. 5 ;  
       FIG. 10  is a flowchart illustrating the operation when a user sets a desired color;  
       FIG. 11  is a perspective view illustrating an example of a setup screen in case of setting the color by selecting a color temperature;  
       FIG. 12  is a perspective view illustrating an example of the setup screen in case of setting the color by adjusting the intensity of each color;  
       FIG. 13  is a perspective view illustrating an example of the setup screen in case of setting the brightness;  
       FIG. 14  is a block diagram illustrating a liquid crystal display unit according to a third embodiment of the present invention;  
       FIG. 15  is a block diagram illustrating a configuration of an LCD module as shown in  FIG. 14 ;  
       FIG. 16  is a perspective view illustrating the LCD module and a flexible cable as shown in  FIG. 14 ; and  
       FIG. 17  is a perspective view illustrating an example of the LCD module and the flexible cable for the purpose of comparison with the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. First, a first embodiment of the present invention will now be described.  FIG. 5  is a block diagram illustrating a liquid crystal display unit according to the first embodiment, while  FIG. 6  is a block diagram illustrating a control section shown in  FIG. 5 .  FIG. 7  is a diagram illustrating a composite data signal outputted from the control section as shown in  FIG. 5  in time series, while  FIG. 8  is a block diagram illustrating a backlight drive section as shown in  FIG. 5 .  FIG. 9  is a block diagram illustrating an LCD module as shown in  FIG. 5 . The liquid crystal display unit according to the first embodiment is mounted on a portable device such as a mobile phone  71  (refer to  FIG. 11 ).  
      As shown in  FIG. 5 , the liquid crystal display unit according to the first embodiment is generally comprised of five blocks, namely, an input section  1 , a control section  2 , a storage section  3 , a backlight drive section (drive section)  4 , and an LCD module  7 . The LCD module  7  is comprised of a backlight  5  and an LCD panel  6 .  
      The input section  1  is a circuit for receiving input information  10  from a key (not shown) provided on the portable device and subsequently outputting the input information  10  to the control section  2 . The control section  2  reads LED electric current data stored in the storage section  3  based on the input information  10  inputted from the input section  1  to control the backlight drive section  4 , and controls the LCD panel  6  based on the input information  10  and a video signal  11 . The storage section  3  includes, for example, a memory, and stores, the LED electric current data (or power data) for representing an electric current value of an LED provided in the backlight  5 . The LED electric current data is referred to when the control section  2  selects the color of the white color display of the LCD panel  6 . The backlight drive section  4  provides the backlight  5  with an electric current according to the LED electric current data. As shown in  FIG. 5 , a part of a signal (first signal) outputted to the backlight drive section  4  from the control section  2  and a part of a signal (second signal) outputted to the LCD panel  6  from the control section  2  are transmitted via the same signal line (common signal line)  8 . The signal line  8  is a composite wire comprised of, for example, eighteen wirings.  
      Configurations of each block will be hereinbelow described in detail. As shown in  FIG. 6 , the control section  2  is comprised of an input information processing section  21 , a backlight control section  22 , an LCD panel control section  23  including an image memory  28  and a controller  24 . The input information processing section  21  is a circuit for receiving the input information from the input section  1 , and processing the input information  10  to sort to the backlight control section  22  and the LCD panel control section  23 . The backlight control section  22 , based on the input information  10  inputted from the input information processing section  21 , selects the LED electric current data from a table stored in the storage section  3  to output selected LED electric current data  25  to the controller  24 , and outputs a selection signal  29  of three sorts, R, G, and B, of DACs (Digital-Analog Converter) as described later, to the backlight drive section  4 .  
      To the LCD panel control section  23 , the input information  10  sorted by the input information processing section  21  is inputted, and the video signal  11  is inputted from the outside of the liquid crystal display unit. The LCD panel control section  23  generates image data  26  with RGB having 6 bits each from the video signal  11 , or information stored in the image memory  28 , and outputs the same to the controller  24  and outputs a control signal  30  to the LCD panel  6 . The control signal  30  includes a serial I/F (Interface) signal for performing various settings to an LCD drive circuit (to be described later) provided in the LCD panel, a horizontal synchronizing signal outputted every horizontal scanning period, a vertical synchronizing signal outputted every vertical scanning period, and a clock signal in synchronization with a composite data signal  27  to be described later.  
      To the controller  24 , the LED electric current data  25  with RGB, each color having 6 bits, is inputted from the backlight control section  22 , and the image data  26  with RGB, each color having 6 bits, is inputted from the LCD panel control section  23 . The controller  24  generates the composite data signal  27  based an the LED electric current data  25  and the image data  26 , and outputs the same to both the backlight drive section  4  and the LCD panel  6  (refer to  FIG. 15 ).  
      The composite data signal  27  is a digital signal with RGB, each color having 6 bits. As shown in  FIG. 7 , the composite data signal  27  includes the LED electric current data (first signal)  25  and the image data (second signal)  26  in a time-division format during one frame cycle, namely, during a cycle for rewriting one screen of an image. In other words, in the composite data signal  27 , the LED electric current data  25  is inserted during the period of time from when output of one screen of the image data  26  in a certain frame was completed to when output of the image data  26  in the next frame is started. Thus, the image data  26  and the LED electric current data  25  can be outputted to both the backlight drive section  4  and the LCD panel  6  without having any effect on the display (refer to  FIG. 5 ). Note herein that, the LED electric current data  25  is outputted every frame in the first embodiment, however, the same can be outputted only at the time of changing the data.  
      The image data  26  included in the composite data signal  27  is of 18 bits of digital signals, in total, of each color having 6 bits. The digital signals are then transmitted in parallel using eighteen wirings constituting the signal line  8 . Namely, placing one bit of a digital signal on one wiring, the 18 bits of digital signals may simultaneously be transmitted. Meanwhile, the LED electric current data  25  included in the composite data signal  27  is also of 18 bits of digital signals, in total, each color having 6 bits. However, the LED electric current data  25  is transmitted using six wirings out of the eighteen wirings constituting the signal line  8 . That is, the three colors of data are transmitted every color in a time-division format.  
      As shown in  FIG. 8 , the backlight drive section  4  includes a switch section  41 . The switch section  41  is comprised of switches  41 R,  41 G, and  41 B corresponding to each color, RGB. The composite data signal  27  outputted from the controller  24  of the control section  2  is inputted into each of one end of the switches  41 R,  41 G and  41 B. On/off of each switch is controlled by the selection signal  29  outputted from the backlight control section  22  of the control section  2 . An input terminal of a DAC  42 R is connected to the other end of the switch  41 R, and a drive circuit  43 R is connected to an output terminal of the DAC  42 R. Similarly, a DAC  42 G and a drive circuit  43 G are connected to the other end of the switch  41 G in this order, and a DAC  42 B and a drive circuit  43 B are connected to the other end of the switch  41 B to in this order.  
      The switch section  41  sorts the data of each color of the LED electric current data  25  included in the composite data signal  27  to the DACs  42 R,  42 G, and  42 B. For example, the switch  41 R takes out only red color data of the LED electric current data  25  from the composite data signal  27  and outputs the same to the DAC  42 R. The DAC  42 R converts a digital voltage signal inputted from the switch  41 R into an analog voltage signal. The drive circuit  43 R converts the analog voltage signal inputted from the DAC  42 R into an electric current signal and provide the same to a red LED  51 R of the backlight  5  (refer to  FIG. 9 ). The switch  41 G, the DAC  42 G the drive circuit  43 G, the switch  41 B, the DAC  42 B and the drive circuit  43 B, have similar functions, and each of the same deals green color data and blue color data. Since the LED electric current data  25  includes the data of RGB, each color having 6-bits, the DACs can output the electric current with 64 gradations, respectively. Hence, approximately 260,000 series of electric current settings can be made for the whole of RGB. Note herein that, when such detailed electric current settings are not required, the number of bits of the LED electric current data  25  may be reduced.  
      As shown in  FIG. 9 , the backlight  5  of the LCD module  7  has three sorts of LEDs,  51 R,  51 G, and  51 B (hereinafter also collectively referred to as LEDs  51 ) for emitting lights of each color of RGB, and a light guiding plate (not shown) for synthesizing the lights entered from the LEDs  51  and outputting the same to the LCD panel  6  in a planar form.  
      The LCD panel  6  of the LCD module  7  includes a display section  61 . The display section  61  includes a plurality of scanning lines (not shown) extending in a horizontal direction (transverse direction) of a screen and a plurality of data lines (not shown) extending in a vertical direction (longitudinal direction) of the screen, and is comprised of a plurality of pixels provided every nearest point of contact of the scanning line and the data line. The display section  61  is provided with a color filter (not shown). The LCD panel  6  also includes a scanning line drive circuit  62  for sequentially selecting the scanning line for performing a vertical scanning, and an LCD drive circuit  63  connected to the scanning line drive circuit  62  and the data lines. The control signal  30  and the image data  26  among the composite data signal  27  are inputted to the LCD drive circuit  63 , and thereby, the LCD drive circuit  63  generates a control signal for controlling the scanning line drive circuit  62 , and writes the image data  26  into each pixel of the display section  61  via the data lines. Since the image data  26  is of a signal including data of colors, each having 6 bits, the display section  61  can perform the color display with 260,000 colors.  
      Next, the operation of the liquid crystal display unit according to the first embodiment configured as explained above will be described with reference to  FIGS. 5 through 9 .  
      First, the operation at the time of power activation of the mobile phone will be described. When the power of the mobile phone is activated, the LCD panel control section  23  of the control section  2  as shown in  FIG. 6  outputs the control signal  30  to the LCD drive circuit  63  of the LCD panel  6 . In other words, the LCD panel control section  23  outputs the serial I/F signal to perform various sorts of settings for activating the LCD drive circuit  63 , and also outputs other control signals (the horizontal synchronizing signal, the vertical synchronizing signal, and the data clock signal). The LCD drive circuit  63  generates the control signal for the scanning line drive circuit  62  based on the serial I/F signal, and puts the scanning line drive circuit  62  into operation. Through the above-mentioned operation, the LCD panel  6  enters a wait state for the composite data signal  27 . Moreover, the LCD panel control section  23  reads start-up image data stored in the image memory  28 , and outputs the same to the controller  24  as the image data  26 .  
      Meanwhile, a table as preliminarily shown in Table 1 is stored in the storage section  3 . As shown in Table 1, 6 bits of data representing the LED electric current value of each of RGB every color is stored in the table. For example, the electric current value being applied to the red LED  51 R in the color having a color temperature of 6500 K is stored in the storage section  3  as 6 bits of data R 3 . The backlight control section  22  reads the LED electric current data  25  corresponding to a predetermined color, for example, the LED electric current data  25  having the color temperature of 6500 K from the storage section  3  in the tables as shown in Table 1 and outputs the same to the controller  24 .  
                       TABLE 1                                      LED Electric current data                                     Color Temperature   R   G   B                       . . .   . . .   . . .   . . .           5500K   R1   G1   B1           6000K   R2   G2   B2           6500K   R3   G3   B3           7000K   R4   G4   B4           7500K   R5   G5   B5           . . .   . . .   . . .   . . .                      
 
      The controller  24  synthesizes the image data  26  for representing the start-up image transmitted from the LCD panel control section  23  and the LED electric current data  25  transmitted from the backlight control section  22  and thereby, generates the composite data signal  27  (refer to  FIG. 7 ). The controller  24  outputs to both the switch section  41  of the backlight drive section  4  and the LCD drive circuit  63  of the LCD panel  6  through the signal line  8 . At this time, the image data  26  included in the composite data signal  27  is transmitted in parallel using the eighteen wirings constituting the signal line  8 . Meanwhile, the LED electric current data  25  transmits three-color data in a time-division format, using six wirings out of the eighteen wirings constituting the signal line  8 .  
      The LCD drive circuit  63  downloads the image data  26  included in the composite data signal  27 . The LCD drive circuit  63  then writes the image data  26  into the data lines in synchronization with the moment when the scanning line drive circuit  62  sequentially selects the scanning line of the display section  61 . Thus, the image represented by the image data  26 , namely, the start-up image is displayed on the display section  61 .  
      Meanwhile, the backlight control section  22  of the control section  2  outputs the selection signal  29  to the switch section  41  of the backlight drive section  4 , and sequentially turns on the switches  41 R,  41 G, and  41 B. Thus, the red color data R 3 , the green color data G 3 , and the blue color data B 3  of the LED electric current data  25  as shown in Table 1 are taken out from the composite data signal  27  and provided to the DAC  42 R, the DAC  42 G, and the DAC  42 B, respectively. Each of the red color data R 3 , the green color data G 3 , and the blue color data B 3  is of 6 bits of digital voltage signal, respectively. Subsequently, the DAC  42 R converts the red color data R 3  into the analog voltage signal, and the drive circuit  43 R then converts the analog voltage signal into the analog electric current signal to provide the same to the LED  51 R of the backlight  5 . Similarly, the DAC  42 G converts the green color data G 3  into the analog voltage signal, and the drive circuit  43 G then converts the same into the analog electric current signal to provide the same to the LED  51 G. Moreover, the DAC  42 B converts the blue color data B 3  into the analog voltage signal, and the drive circuit  43 B then converts the same into the analog electric current signal to provide the same to the LED  51 B. Thus, receiving the electric current signals after conversion, the LED  51  of the backlight  5  emits light with brightness according to the electric current signals. The light is synthesized and emitted in a planar form, by the light guiding plate, being illuminated to the LCD panel  6 . As a result of this, the LCD module  7  sets the white color display to a predetermined color and displays the image.  
      Next, the operation in case that a user sets a desired color will be described.  FIG. 10  is a flowchart illustrating the operation in case that a user sets the desired color, while  FIG. 11  is a perspective view illustrating the setup screen in case that the color is set by selecting the color temperature.  FIG. 12  is a perspective view illustrating a setup screen in case that the color is set by adjusting intensity of each color, while  FIG. 13  is a perspective view illustrating the setup screen in case that the brightness thereof is set.  
      First, at Step S 1  in  FIG. 10 , the user selects a color setting by a key input. Thus, at Step S 2 , the LCD panel control section  23  of the control section  2  selects the image data  26  for representing the setup screen as shown in  FIG. 2011  from the image data stored in the image memory  28 , and outputs the same to the controller  24 . The controller  24  replaces only the image data  26  in the composite data signal  27 , and then outputs the same to the LCD panel  6  as the new composite data signal  27 . As a result of this, the display panel  6  of the mobile phone  71  displays the setup screen as shown in  FIG. 11 . At this time, a background color of the setup screen has been changed into the white color.  
      Next, at Step S 3  in  FIG. 10 , the user, while watching the setup screen as shown in  FIG. 11 , selects the color temperature by operating up/down keys so as to obtain the desired color. For example, the user may select 7000 K by increasing the color temperature by one level from 6500 K. The input information  10  inputted by the key input is inputted to the control section  2  via the input section  1 . The input information processing section  21  of the control section  2  receives the input information  10 , and then sends an instruction to the backlight control section  22  and the LCD panel control section  23 .  
      Based on the instruction, the backlight control section  22  reads the LED electric current data  25  corresponding to the selected color temperature (for example, 7000 K) from the table (refer to Table 1) stored in the storage section  3 , and outputs the same to the controller  24 . Meanwhile, the LCD panel control section  23  reads, from the image memory  28 , the image data of the image indicating the color temperature (for example, 7000 K) that is selected by the user, and outputs the same to the controller  24  as the image data  26 . The image is the one in which an indication of “6500 K” in the setup screen as shown in  FIG. 11  has been changed to an indication of “7000 K”, for example.  
      The controller  24  changes the image data  26  and the LED electric current data  25 , respectively, and generates the new composite data signal  27  to output the same to the backlight drive section  4  and the LCD panel  6 . As a result of this, the color of the background color (white color) of the setup screen displayed on the display section  61  is changed to the color with the selected color temperature.  
      Next, the process proceeds to Step S 4 . At Step S 4 , if the selected color does not meet the color of a user&#39;s preference, the process returns to Step S 3 , and then Steps S 3  and S 4  are repeated until the color meets that of the user&#39;s preference. If the color of the background color of the setup screen meets that of the user&#39;s preference, the process proceeds to Step S 5 . At Step S 5 , the LED electric current data  25  that the backlight control section  22  reads from the storage section  3  at the time of start-up of the mobile phone is changed to the data set by the user from the data set at the stage of shipping. As a result of this, the user setting of the color is completed as shown at Step  86 .  
      By performing the above-mentioned operation, thereafter, every time the power of the mobile phone is activated, the backlight control section  22  reads, from the storage section  3 , the LED electric current data  25  corresponding to the color selected by the user, and the LCD module  7  always displays the white color with the color selected by the user.  
      The above-mentioned description is about the operation in case that the user sets the color of the white color display by selecting the color temperature. In the liquid crystal display unit according to the first embodiment, however, the user can set the color of the white color display by adjusting the intensity of each color of RGB, respectively. Hereinafter, the operation for this case will be described.  
      By means of the user&#39;s selection of the color setting, the LCD panel control section  23  selects the image data  26  for representing the setup screen as shown in  FIG. 12  from the image data stored in the image memory  28 , and outputs the same to the controller  24 . Thus, the LCD panel  6  of the mobile phone  71  displays the setup screen as shown in  FIG. 12 . While watching the setup screen, the user individually adjusts the intensity of each color of RGB. For example, if the user desires to intensify R (red), the user slides a bar R toward “high”. Based on this information, the input information processing section  21  of the control section  2  issues an instruction to the backlight control section  22 . The backlight control section  22 , based on this instruction, reads the new LED electric current data  25  from the storage section  3 , and outputs the same to the controller  24 . The subsequent operation is the same as the above-mentioned operation at the time of selecting the color temperature. In a manner described above, the color of the white color display can be set.  
      In addition, in the liquid crystal display unit according to the first embodiment, the brightness of the display may also be changed. Hereinafter, the operation will be described. By means of the user&#39;s selection of a brightness setting, the LCD panel control section  23  reads the image data  26  for representing the setup screen shown in  FIG. 13  from the image data stored in the image memory  28 , and outputs the same. Thus, the LCD panel  6  of the mobile phone  71  displays the setup screen as shown in  FIG. 13 . While watching the setup screen, the user adjusts the brightness by the key input. In case of changing the brightness, the backlight control section  22  outputs an electric current obtained by multiplying the LED electric current data  25  by a certain gain (coefficient). Thus, the electric current values can be uniformly increased or decreased without changing a relative ratio of the electric current values being applied to the LEDs,  51 R,  51 G, and  51 B. Since the brightness of the LED increases in proportion to the electric current, it is possible to change the brightness by such operation without changing the color of the display. Note herein that, if the brightness of the LED becomes non-linear to the electric current value, the gain according to the non-linear characteristic may be stored in the storage section  3  in advance and the backlight control section  22  may select the gain in accordance with the brightness setting.  
      When also adjusting the brightness, the background color of the display becomes a white color, and the brightness of a background white color display is changed in accordance with the key input. After a brightness adjustment is completed, the new LED electric current data  25  is set to the backlight control section  22 . As a result of this, thereafter, every time the power of the liquid crystal display unit is activated, the new LED electric current data  25  is outputted from the backlight control section  22 , and thereby, the LCD module  7  can always display with the brightness selected by the user.  
      Next, effects according to the first embodiment will be described. In the first embodiment, the storage section  3  stores the LED electric current data corresponding to a plurality of colors. For this reason, when it is desired to change the color of the white color display, it is possible to easily change the color of white color display by reading the LED electric current data stored in the storage section  3 .  
      In addition, in the first embodiment, the controller  24  of the control section  2  synthesizes the LED electric current data  25  and the image data  26 , and generates the composite data signal  27  to transmit the combined data to both the backlight drive section  4  and the LCD panel  6  via the signal line  8 . As a result of this, it is possible to decrease the number of the signal lines for transmitting the LED electric current data  25  and the image data  26 , and to reduce the circuit area for arranging the signal lines. Thus, it is possible to work for a reduction in size and weight of the liquid crystal display unit instead of using an expensive narrow-pitch wiring board or multilayer wiring board. As a result of this, it is possible to work out for reduce in size and weight, and cost reduction of the mobile phone mounting the liquid crystal display unit.  
      Further, according to the first embodiment, it is possible to set the color of the white color display by both selecting the color temperature and adjusting the intensity of each color. Hence, the user can select a method for operating more easily, and set the color. Still further, it is possible to easily adjust the brightness of the display without providing a specific component for adjusting the brightness of the display.  
      Incidentally, the first embodiment shows the example where the LED electric current data  25  included in the composite data signal  27  is transmitted in a time-division format, using the six wirings out of the eighteen wirings constituting the signal line  8 , however, the present invention is not limited thereto. For example, the LED electric current data  25  can be transmitted, using all of eighteen wirings constituting the signal line  8 . In this case, the eighteen wirings are divided into six wirings each, for example, and each may be connected to the DACs  42 R,  42 G, and  42 B of the backlight drive section  4  as shown in  FIG. 8 , respectively. This allows the data of each color of the LED electric current data  25  to be directly inputted to the DACs  42 R,  42 G, and  42 B, respectively. As a result of this, it is possible to eliminate the switch section  41  and the selection signal  29 .  
      Next, a second embodiment of the present invention will be described. The second embodiment differs from the first embodiment in the table stored in the storage section  3  (refer to  FIG. 5 ). Table 2 shows the table stored in the storage section  3  of the liquid crystal display unit according to the second embodiment. As shown in Table 2, in the table, the color temperature is set corresponding to a region where the mobile phone is used, and the LED electric current data corresponding to each color temperature is stored therein. The configuration in the second embodiment other than explained above is similar to that of the first embodiment.  
                       TABLE 2                                      LED electric current data                                 Region   Color Temperature   R   G   B               . . .   . . .   . . .   . . .   . . .       (1)   5500K   R1   G1   B1       (2)   6000K   R2   G2   B2       (3)   6500K   R3   G3   B3       (4)   7000K   R4   G4   B4       (5)   7500K   R5   G5   B5       . . .   . . .   . . .   . . .   . . .                  
 
      Next, the operation and effect of the second embodiment will be described. In the actual market, there may be a case that the desired color differs depending on the region. Hence, as for the liquid crystal display unit according to the second embodiment, in a process for performing settings of the various data before products&#39; shipment, information indicating the region to which products are shipped, for example, “region (3)” shown in Table 2, is inputted into the liquid crystal display unit. The information indicating the region is inputted into the input information processing section  21  of the control section  2  via the input section  1  shown in  FIG. 5 . Based on the information, the input information processing section  21  sends an instruction to the backlight control section  22 . Based on the instruction, the backlight control section  22  reads the data corresponding to “region (3)”, namely, the LED electric current data  25  corresponding to the color with the color temperature of 6500 K, from the storage section  3 . The subsequent operation is similar to that of the first embodiment.  
      As a result of this, the LED electric current data  25  set in accordance with the region becomes as default setting data, and thereafter, the white color display is performed with this color every time the power of the mobile phone is activated. This state is continued until the next color is set, for example, the user setting is performed. This makes it possible to set the color of the white color display to a color corresponding to the region at the time of shipping products, and to correspond to the user preference that differs depending on the region. Moreover, in case of changing the color by the user setting after shipment, it can be performed in a manner similar to that of the first embodiment. The operation and effect of the second embodiment other than explained above are similar to those of the first embodiment.  
      Incidentally, the color may be set in accordance with the region after shipping products. For example, a region where the portable device is used may be identified in cooperation with an international roaming to set a color corresponding to the region. Moreover, in case of a mobile phone mounting a GPS (Global Positioning System) device, the color may be set based on positional information obtained by the GPS device and inputted in the control section  2  as shown in  FIG. 5 .  
      Next, a third embodiment of the present invention will be described.  FIG. 14  is a block diagram illustrating a liquid crystal display unit according to the third embodiment, while  FIG. 15  is a block diagram illustrating an LCD module shown in  FIG. 14 .  FIG. 16  is a perspective view illustrating the LCD module shown in  FIG. 14  and a flexible cable, while  FIG. 17  is a perspective view illustrating the LCD module and the flexible cable for the purpose of comparison. Note herein that, in  FIG. 14 , the display section (reference numeral  61  in  FIG. 9 ) and the scanning line drive circuit (reference numeral  62  in  FIG. 9 ) are omitted for the purpose of simplifying the drawing.  
      As shown in  FIGS. 14 and 15 , in the liquid crystal display unit according to the third embodiment, the backlight drive section  4  is provided inside the LCD panel  6 . Additionally, the selection signal (third signal)  29  outputted from the control section  2  to the backlight drive section  4  is a serial I/F signal, which is transmitted via a common flexible cable (another common signal line)  13  (refer to  FIG. 16 ) shared with the serial I/F signal of the control signal (fourth signal)  30  outputted to the LCD panel  6  from the control section  2 .  
      As shown in  FIG. 16 , in the liquid crystal display unit according to the third embodiment, the flexible cable  13  and a connector  14  are used. One end of the flexible cable  13  is connected to the LCD panel  6 , while the other end is connected to the connector  14 . The connector  14  is connected to the backlight control section  22  and the LCD panel control section  23  of the control section  2  as shown in  FIG. 6 . The backlight control section  22  transmits the selection signal  29  to the backlight drive section  4  arranged in the LCD panel  6  via the connector  14  and the flexible cable  13 , while the LCD panel control section  23  transmits the control signal  30  to the LCD drive circuit  63  of the LCD panel  6  via the connector  14  and the flexible cable  13 . Moreover, the control section  2  outputs a selection signal  31  to the LCD panel  6 . The selection signal  31  indicates to which of the backlight drive section  4  and the LCD panel  6 , the serial I/F signal transmitted via the flexible cable  13  is outputted.  
      Meanwhile, a flexible cable  15  is connected between the LCD panel  6  and the backlight  5 . The backlight drive section  4  arranged in the LCD panel  6  provides the LEDs  51  of the backlight  5  with the electric currents through the flexible cable  15 . Any connector is not connected to the flexible cable  15 . Hence, only one connector (connector  14 ) is provided in the third embodiment. The configuration of the third embodiment other than the stated above is similar to that of the first embodiment.  
      In the liquid crystal display unit in  FIG. 17  shown for the purpose of comparison, a flexible cable  113  is provided, one end of which is connected to the LCD panel  6 , and the other end of which is connected to a connector  114 . The connector  114  is connected to the LCD panel control section. Meanwhile, a flexible cable  115  is provided, one end of which is connected to the LED of the backlight  5 , and the other end of which is connected to a connector  116 . The connector  116  is connected to the backlight control section.  
      As described above, in the liquid crystal display unit shown in  FIG. 17  for the purpose of comparison, the LCD panel control section and the LCD panel  6  are connected by the connector  114  and the flexible cable  113 , while the backlight control section and the backlight  5  are connected by the connector  116  and the flexible cable  115 . That is to say, it means that two connectors are required.  
      As described above, in the liquid crystal display unit in the third embodiment as shown in  FIGS. 14 through 16 , as compared with the liquid crystal display unit as shown in  FIG. 17 , the connector  116  connecting the backlight drive section  4  with the LEDs  51  may be eliminated. As a result of this, it is possible to establish reduction in size, weight, and cost of the liquid crystal display unit and that of the portable device having the same.  
      Moreover, in the third embodiment, the selection signal  29  transmitted from the backlight control section  22  to the backlight drive section  4  is commonized with the control signal  30  transmitted from the LCD panel control section  23  to the LCD drive circuit  63 . Hence, in the third embodiment, the signal added between the backlight control section  22  and the backlight drive section  4  is only the selection signal  31  for indicating to which of the backlight drive section  4  and the LCD panel  6 , the serial I/F signal that is transmitted through the flexible cable  13  is outputted. As a result of this, the number of signal lines in the conventional liquid crystal display unit is almost the same as that of the signal lines connecting between the LCD panel control section and the LCD panel. The operation and effect of the third embodiment other than the described above are similar to those of the first embodiment.  
      Incidentally, in the third embodiment, the backlight drive section  4  and the LCD drive circuit  63  may be comprised of the same IC (Integrated Circuit). Thus, it is possible to establish further reduction in size and cost of the liquid crystal display unit.  
      In addition, a connection form as shown in  FIG. 16  may also be applicable to the first and second embodiments. Also in this case, the connector that has conventionally been provided for connecting between the backlight drive section  4  and the LEDs  51  can be eliminated. In this case, however, since three signal lines are added in addition to the flexible cable  13  between the backlight drive section  4  and the LEDs  51 , a total number of connection lines increase more than the number in the third embodiment.  
      Further, in the first through third embodiments, there have been provided an exemplification in which the image data  26  and the LED electric current data  25  are commonized to thereby generate the composite data signal  27 . However, the LED electric current data  25  may be formed in the serial I/F signal and commonized with the control signal  30  that is the serial I/F signal. Additionally, the signals may be used in common using a manner other than described above.  
      Furthermore, in the first through third embodiments, there has been provided a description of such a type of LCD module that the three-color LEDs  51  may simultaneously be lit up. However, the present invention is not limited thereto, and the three-color LEDs  51  may be sequentially lit up. This type of LCD module is referred to as a field sequential drive LED module. Namely, the field sequential drive LED module sequentially displays the RGB images on the display section  61  in synchronization with a timing of light-up of the three-color LEDs  51  and impresses the user on the color image obtained by synthesizing each of images having RGB, respectively.  
      Furthermore, in the first through third embodiments, there has been provided an exemplification of the mobile phone as the portable device. However, the portable device of the present invention is not limited to the mobile phone but may include, for example, a PDA (Personal Digital Assistance), a note-type personal computer, or the like.