Patent Publication Number: US-2007097068-A1

Title: Display apparatus and information processing apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2005-317533, filed Oct. 31, 2005, the entire contents of which are incorporated herein by reference.  
     BACKGROUND  
      1. Field  
      One embodiment of the invention relates to a display apparatus using a backlit liquid crystal display panel, and an information processing apparatus having the display apparatus.  
      2. Description of the Related Art  
      It is disclosed by, for example, Jpn. Pat. Appln. KOKAI Publication No. 2002-72234 to develop a liquid crystal display apparatus which uses a light emitting element such as an LED as a backlight light source, instead of a fluorescent tube.  
      A portable information processing apparatus having this type of liquid crystal display apparatus requires a circuit packaging technique for increasing the number of functions. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
      A general architecture that implements the various features of the invention will now be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate embodiments of the invention and not to limit the scope of the invention.  
       FIG. 1  is a block diagram showing the arrangements of a display apparatus and an information processing apparatus according to a first embodiment of the invention;  
       FIG. 2  is a block diagram showing the arrangements of the display apparatus and the information processing apparatus according to the first embodiment;  
       FIG. 3  is a perspective view showing the outer appearance of a more practical information processing apparatus according to a second embodiment of the invention;  
       FIG. 4  is a block diagram showing the system configuration of the more practical information processing apparatus according to the second embodiment;  
       FIG. 5  is a block diagram showing the arrangements of a display apparatus and an information processing apparatus according to a third embodiment of the invention; and  
       FIG. 6  is a block diagram showing the arrangements of a display apparatus and an information processing apparatus according to a fourth embodiment of the invention.  
    
    
     DETAILED DESCRIPTION  
      Various embodiments according to the invention will be described hereinafter with reference to the accompanying drawings. In general, according to one embodiment of the invention, there is provided a display apparatus comprising a display panel, a light emitting element arranged as a light source for the display panel, a board on which a first circuit for controlling power supply to the light emitting element is arranged, and a second circuit which is arranged on the board and executes a process unrelated to a drive process of the display panel.  
      According to another embodiment of the invention, there is provided an information processing apparatus comprising a main body which incorporates a first board, and a display unit arranged to be pivotal with respect to the main body. Note that the display unit further comprises a display panel, a light emitting element arranged as a light source for the display panel, a second board on which a first circuit for controlling power supply to the light emitting element is arranged, and a second circuit which is arranged on the second board and connected to a circuit arranged on the first board, and which executes a process unrelated to a drive process of the display panel.  
      According to an embodiment,  FIG. 1  shows the arrangements of a display apparatus and an information processing apparatus using this display apparatus according to the first embodiment of the present invention.  
      The information processing apparatus according to the embodiment of the present invention has a main body  10  serving as a main part of the information processing apparatus, and a display unit  20  serving as a display apparatus. The display unit  20  is supported to be pivotal about a hinge unit  30  with respect to the main body  10 . The main body  10  has a system circuit board  11 . A system circuit  12 A including a CPU, its peripheral circuit, various buses, and various controllers connected to these buses is arranged on the system circuit board  11 .  
      The display unit  20  has an liquid crystal display (LCD) panel  21 , and a sub-board (circuit board)  23  associated with the LCD panel  21 . The LCD panel  21  has a backlight  22  using an LED as a light source.  
      A backlight power supply circuit (LED/BL-PS)  24  which on/off-drives the LED serving as the light source for the backlight  22  is arranged on the sub-board  23 . An additional circuit  25  unrelated to driving of the LCD is also arranged on the sub-board  23 . The additional circuit  25  comprises a user interface (IF)  26 . The user interface  26  has a user interface function of handling a signal input to the system circuit board  11 , and that of handling a signal to be output from the system circuit board  11 . Alternatively, the user interface  26  has one of these user interface functions.  
      The additional circuit  25  which is arranged on the sub-board  23  and comprises the user interface  26  is electrically connected to the system circuit board  11  arranged in the main body  10 . Such electrical connection is established using a signal line extending through a through hole formed in the hinge unit  30 . This signal line is, e.g., a serial bus connected to a serial bus interface, an analog signal line, or a USB cable. When the through hole has a large diameter, the signal line may be a parallel bus having a width of a plurality of bits. The serial bus is suitable to be applied when the number of signal lines extending through the through hole in the hinge unit  30  is strictly limited.  
      The serial bus can be applied when the number of signal lines extending through the through hole in the hinge unit  30  is limited in the circuit arrangement in which a digital signal such as a command and data is transferred between the system circuit board  11  and the additional circuit  25 . For example, the serial bus can be applied to the following circuit arrangement. In this circuit arrangement, a digital signal is transmitted from an I/O controller  12 B on the system circuit board  11  in the main body  10  to the additional circuit  25  on the sub-board  23  in the display unit  20 . The additional circuit  25  then digital-to-analog-converts the transmitted digital signal, and outputs the converted signal to the user interface  26 . Alternatively, the serial bus can be applied to the circuit arrangement in which the additional circuit  25  generates a command (or data) according to the operation state of the user interface  26 , and transmits the generated command to the system circuit board  11 .  
      The analog signal line can be applied when various analog signals related to the user interface are transmitted/received between the system circuit board  11  and the additional circuit  25 . For example, the analog signal line can be applied to the following circuit arrangement. In this circuit arrangement, the I/O controller  12 B arranged on the system circuit board  11  transmits a digital-to-analog-converted signal (e.g., audio signal) to the additional circuit  25 . The additional circuit  25  then analog-amplifies the transmitted signal, and outputs the amplified signal to the user interface  26 . Alternatively, the analog signal line can be applied to the circuit arrangement in which the additional circuit  25  analog-amplifies the analog signal (e.g., microphone input signal) from the user interface  26  to transmit the amplified signal to the system circuit board  11 , and the system circuit board  11  analog-to-digital-converts the above analog signal to input the converted signal.  
      When the USB cable is used, video, audio, and operation instruction signals handled by the user interface can be transmitted/received between the system circuit board  11  and the additional circuit  25  by performing isochronous transfer to transfer sound data, image data, and the like between the system circuit board  11  and the additional circuit  25 , and interrupt transfer to transfer pointing device data from the additional circuit  25  to the system circuit board  11 .  
      The following circuit arrangement can also be implemented. In this circuit arrangement, a control circuit (CNT)  29  which comprises a microprocessor and controls data transfer between the sub-board  23  and the system circuit board  11  is arranged on the sub-board  23 . Under the control of the control circuit  29 , each of the backlight power supply circuit  24  and additional circuit  25  on the sub-board  23  transmits/receives data to/from the system circuit board  11 . In this case, the signal line can be shared. As another example, the control circuit  29  can also control both or one of the backlight power supply circuit  24  and additional circuit  25  on the sub-board  23 . For example, one of the following two processing functions can be implemented: inputting reception data from the system circuit board  11  to the control circuit  29  to execute a predetermined process, and transmitting the processed data to the additional circuit  25  and the system circuit board  11 ; and processing the data from the additional circuit  25  to perform input/output control for the user interface  26 , and transmitting the processed data to the system circuit board  11 . Note that the control circuit  29  is arranged on the sub-board  23  alone. However, the present invention is not limited to this. For example, the control circuit  29  may be incorporated in the additional circuit  25  or the backlight power supply circuit  24 .  
      As described above, the additional circuit  25  with the user interface  26  is arranged on the sub-board  23  on which the backlight power supply circuit  24  is arranged. In this arrangement, when a new functional circuit is to be added in order to increase the number of functions, the functional circuit with the user interface  26  can be arranged as the additional circuit  25  in the display unit  20  without ensuring a mounting space on the system circuit board  11  or without ensuring a board mounting space in the display unit  20 . Accordingly, a multifunctional apparatus can be easily implemented (the function can be extended) without degrading operability.  
      Also, the number of functions can be increased using an economically advantageous circuit packaging means without degrading operability. For example, when the LED is used for the backlight light source for a backlit LCD panel in place of the fluorescent (FL) tube, the backlight power supply circuit which handles a high-voltage power supply for on/off-driving the fluorescent tube need not be mounted on the backlight power supply circuit board (sub-board) associated with the LCD panel. The backlight power supply circuit is replaced with a small-scale and low-voltage circuit for on/off-driving the LED. Hence, a sufficient mounting space for mounting another functional circuit can be ensured on the backlight power supply circuit board. A sufficient wiring space can also be ensured in the through hole in the hinge unit. Accordingly, both of the backlight power supply circuit and the functional circuit with the user interface can be arranged on the backlight power supply circuit board (sub-board) without ensuring a new board mounting space in the display unit. As a result, the design of the display unit and main body need not be largely changed, and the function can be extended by the additional circuit in an economically advantageous arrangement in which the present sub-board or the board mounting space is efficiently used.  
      When connection plugs such as a connector, plug, and jack, and user interfaces including operation devices such as a jog dial and switch to be used by the user are mounted on the display unit housing, the function can be extended by the additional circuit with excellent operability, without ensuring a new mounting space for the user interface in the main body to extend the function.  
      When some functional circuits mounted on the system circuit board  11  are moved as the above additional circuits to the sub-board in the display unit, a new functional circuit can be added to the system circuit board  11 . Additionally, when the above display unit  20  is applied to a tablet information processing apparatus, a multifunctional tablet information processing apparatus with excellent operability can be implemented.  
      The second embodiment of the present invention as a more practical example of the first embodiment of the present invention will be described below.  
       FIG. 2  shows the arrangements of a display apparatus and an information processing apparatus using the display apparatus according to the second embodiment of the present invention. The second embodiment exemplifies the arrangement in which a sound circuit  251  is arranged as an additional circuit on a sub-board  23 . Note that the same reference numerals in  FIG. 2  denote the same components as those in  FIG. 1 , and a description thereof will be omitted.  
      In addition to a backlight power supply circuit  24  which on/off-drives the LED as the light source for a backlight  22 , the sound circuit  251  as the additional circuit is arranged on the sub-board  23  in a display unit  20 . The sound circuit  251  comprises an audio jack (JK)  252  used by a user, and a variable controller (VR)  253  operated by the user, as user interfaces. The audio jack (JK)  252  is, e.g., a headphone jack or microphone jack. The variable controller  253  is, e.g., a variable resistor for adjusting volume control, or an operation device such as a jog dial.  
      The sound circuit  251  which is arranged on the sub board  23  and comprises the audio jack  252  and the variable controller  253  is electrically connected to a sound controller  126  arranged on a system circuit board  11  in a main body  10 .  
      The second embodiment implements a functional circuit which can input/output various audio signals handled by the user interface to/from the system circuit board  11  via the sound circuit  251  arranged on the sub-board  23 .  
       FIGS. 3 and 4  show the arrangements of the information processing apparatus as a more practical example of the second embodiment.  
       FIG. 3  shows the outer appearance of a more practical information processing apparatus according to the second embodiment. In  FIG. 3 , a battery-drivable and portable notebook personal computer is exemplified. This personal computer comprises the main body  10  and the display unit  20 .  
      The display unit  20  is supported to be pivotal about a hinge unit  30  with respect to the main body  10 . The display unit  20  incorporates, in its housing, a transparent LCD panel  21  whose display surface is exposed from the front surface of the housing. The backlight  22  using an LED as a light source shown in  FIG. 2  is arranged on the back surface of the LCD panel  21 . The audio jack  252  and variable controller  253  connected to the sound circuit  251  shown in  FIG. 2  are also formed on the side surface of the housing of the display unit  20 , in a state wherein a jack, operation dial, and the like are exposed from the housing.  
      The main body  10  has a low-profile box-shaped housing. On the top surface of the housing, a keyboard  13 , a power button  14  used to turn on/off a system power supply, an input operation panel  15 , a touch pad  16 , and the like are arranged. The input operation panel  15  is an input device used to input an event corresponding to a pressed button, and has a plurality of buttons for activating respective functions. The button group also includes a brightness control button  15 A. The brightness control button  15 A is a button switch used to adjust the display brightness of the LCD panel  21 , i.e., the brightness of the LED serving as the light source for the backlight  22 .  
       FIG. 4  shows the internal arrangement of the main body  10  and display unit  20  shown in  FIG. 3 .  
      As shown in  FIG. 2 , the system circuit board  11  in the housing of the main body  10  comprises a CPU  111 , north bridge  112 , main memory  113 , graphics controller  114 , south bridge  119 , BIOS-ROM  120 , hard disc drive (HDD)  121 , optical disc drive (ODD)  122 , embedded controller/keyboard controller (EC/KBC) IC  124 , power supply controller  125 , sound controller  126 , and the like.  
      The power supply controller  125  is connected to a battery  125 A and an AC adapter  125 B, controls power from the battery  125 A or the AC adapter  125 B to be a predetermined value, and supplies power to the EC/KBC  124 .  
      The CPU  111  is a processor which controls operations of the system. The CPU  111  executes an operating system (OS) and various application programs which are loaded from the hard disc drive (HDD)  121  onto the main memory  113  via the south bridge . 119  and the north bridge  112 . The CPU  111  also executes a Basic Input Output System (BIOS) stored in the BIOS-ROM  120 . The BIOS is a program for hardware control. In this case, under the control of the BIOS in accordance with the operation of the brightness control button  15 A, the backlight power supply circuit  24  arranged on the sub-board  23  controls the display brightness (the light quantity of the LED) of the backlight  22  for the LCD panel  21 .  
      The north bridge  112  is a bridge device that connects the local bus of the CPU  111  and the south bridge  119 . The north bridge  112  incorporates a memory controller that executes access control for the main memory  113 . The north bridge  112  also has a function of making a communication with the graphics controller  114  via an Accelerated Graphics Port (AGP) bus or the like.  
      The graphics controller  114  is a display controller which controls the LCD panel  21  of the display unit  20 . The graphics controller  114  has a video memory (VRAM)  114 A, and generates a video signal for forming a display image to be displayed on the LCD panel  21  of the display unit  20 , in accordance with the display data written in the video memory  114 A by the OS/application program.  
      The south bridge  119  controls each device on an Low Pin Count (LPC) bus. The south bridge  119  incorporates an Integrated Drive Electronics (IDE) controller for controlling the HDD  121  and ODD  122 . The south bridge  119  also has a function of executing access control for the BIOS-ROM  120 .  
      Various I/O controllers including the sound controller  126  are connected to the south bridge  119  via a PCI bus  131 . The sound controller  126  connected to the south bridge  119  via the PCI bus  131  performs input/output control for sound data or an analog sound signal under the control of the application program which handles sound information. The sound controller  126  is electrically connected to the sound circuit  251  on the sub-board  23  via a predetermined bus or signal line.  
      The HDD  121  is a storage device for storing various software and data. In the HDD  121 , the above-described operating system and various application systems are stored. The optical disc drive (ODD)  122  is a drive unit for driving a storage medium such as a DVD and CD in which video content is stored.  
      The embedded controller/keyboard controller (EC/KBC) IC  124  is a 1-chip microcomputer on which an embedded controller for power management, and a keyboard controller that controls the keyboard (KB)  13  and touch pad  16  are integrated. When the user presses the brightness control button  15 A, the embedded controller/keyboard controller (EC/KBC) IC  124  generates an interruption signal such as an System Management Interrupt (SMI) in order to notify the BIOS that a display brightness switching event is input.  
      The embedded controller/keyboard controller (EC/KBC) IC  124  has a function of turning on/off the power of the computer  10  in response to user&#39;s operation of the power button  14  in collaboration with the power supply controller  125 .  
      The backlight power supply circuit  24  arranged on the sub-board  23  in the display unit  20  on/off-drives the light source for the backlight  22  arranged on the back surface of the transparent LCD panel  21 . The backlight  22  has a plurality of LEDs serving as light sources for the backlight  22 , and a light guide plate which uniformly illuminates the back surface of the LCD panel  21  with light emitted from each LED.  
      The sound circuit  251  arranged on the sub-board  23  in the display unit  20  comprises the audio jack  252  and variable controller  253  as the user interfaces. The sound circuit  251  is electrically connected to the sound controller  126  via the bus or signal line extending through the hinge unit  30 .  
      The sound circuit  251  implements an interface circuit function for supplying sound information (digital sound data or an analog sound signal) from the sound controller  126  to the user. The sound circuit  251  also implements an interface circuit function for converting the sound information received from the user into a signal form which can be input by the sound controller  126 , and transmits the converted information to the sound controller  126 .  
      The detailed circuit function of the sound circuit  251  will be exemplified below.  
      As the first example, the sound circuit  251  realizes a circuit function of converting (decoding) digital sound data from the sound controller  126  into the analog sound signal, amplifying the converted signal to a sound level according to the operation instruction from the variable controller  253 , and outputting the amplified signal to the audio jack  252 . In this case, such electrical connection between the sound controller  126  and the sound circuit  251  may be serial bus connection, parallel bus connection, or USB cable connection.  
      As the second example, the sound circuit  251  realizes a circuit function of inputting the analog sound signal from the sound controller  126 , amplifying the input signal to the sound level according to the operational instruction from the variable controller  253 , and outputting the amplified signal to the audio jack  252 . In this case, electrical connection between the sound controller  126  and the sound circuit  251  may be signal line connection for transmitting the analog signal.  
      As the third example, the sound circuit  251  realizes a circuit function of amplifying a microphone signal from the audio jack  252  to a predetermined level, converting the amplified signal into the digital signal form which can be input by the sound controller  126 , and supplying the converted signal to the sound controller  126 . In this case, electrical connection between the sound controller  126  and the sound circuit  251  may be serial bus connection, parallel bus connection, or USB cable connection.  
      As the fourth example, the sound circuit  251  realizes a circuit function of amplifying the microphone signal from the audio jack  252  to the sound level according to the operational instruction from the variable controller  253 , and supplying the amplified signal as the analog sound signal to the sound controller  126 . In this case, electrical connection between the sound controller  126  and the sound circuit  251  may be signal line connection for transmitting the analog signal.  
      The above-described various circuit functions are combined, as needed, in accordance with the specification of the user interface to extend a desired sound function on the sub-board  23 .  
      As described above, the sound circuit  251  with the user interfaces is arranged on the sub-board  23  having the backlight power supply circuit  24 . Hence, when a new functional circuit is to be added in order to increase the number of functions, the sound functional circuit with the user interfaces can be arranged as the additional circuit in the display unit  20  without ensuring the mounting space on the system circuit board  11 , and without ensuring a new board mounting space in the display unit  20 . This easily increases the number of functions without degrading operability.  
       FIG. 5  shows the arrangements of a display apparatus and an information processing apparatus using the display apparatus as a more practical example of the first embodiment of the present invention according to the third embodiment of the present invention. The third embodiment exemplifies an arrangement in which a USB power supply circuit  261  is arranged as an additional circuit for a USB port on a sub-board  23 . Note that the same reference numerals in  FIG. 5  denote the same components as those in  FIG. 1 , and a description thereof will be omitted.  
      In addition to a backlight power supply circuit  24  which on/off-drives an LED serving as a light source for a backlight  22 , the USB power supply circuit  261  is arranged as the additional circuit on the sub-board  23  in a display unit  20 . The USB power supply circuit  261  comprises two USB connectors  262  and  263  as user interfaces.  
      The USB power supply circuit  261  has a circuit function of performing power supply control for the USB connectors  262  and  263 , and transmitting/receiving a USB input/output signal between each of the USB connectors  262  and  263  and an I/O controller  12 B having a USB interface on a system circuit board  11 .  
      As a result, the USB port can be easily added, as needed. Since the USB connectors  262  and  263  are mounted on the housing of the display unit  20 , various USB devices can be used independently of the state of a main body  10 . For example, when the USB connectors  262  and  263  are formed on the side or back surface of the housing of the display unit  20 , the USB devices can be easily used when the display unit  20  is opened or closed with respect to the main body  10 .  
       FIG. 6  shows the arrangements of a display apparatus and an information processing apparatus using the display apparatus according to the fourth embodiment of the present invention as a more practical example of the first embodiment of the present invention. The fourth embodiment exemplifies an arrangement in which an interface circuit (camera controller)  271  having an image sensing camera is arranged as an additional circuit on a sub-board  23 . Note that the same reference numerals in  FIG. 6  denote the same components as those in  FIG. 1 , and a description thereof will be omitted.  
      The camera controller  271  serving as the additional circuit is arranged on the sub-board  23  in a display unit  20 , in addition to a backlight power supply circuit  24  which on/off-drives an LED serving as the light source for a backlight  22 . The camera controller  271  comprises an image sensing camera  272 .  
      The camera controller  271  converts image data sensed by the camera  272  into the input format of an image processing function unit  12 C arranged on a system circuit board  11 , and transmits the converted data to the system circuit board  11  via, e.g., a USB cable.  
      Since the camera controller  271  with the camera  272  is arranged as the additional circuit on the sub-board  23  in the display unit  20 , a camera function can be easily extended independently of the state of a main body  10 .  
      The above-described embodiments can be applied not only to a portable computer as shown in  FIG. 3  but also to various information processing devices which require display units  20 . For example, when an embodiment is applied to a tablet information processing apparatus, a multifunctional tablet information processing apparatus with excellent operability can be implemented.  
      While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.