Patent Publication Number: US-2007121020-A1

Title: Information processing device and control method for information processing device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2005-317693, filed Oct. 31, 2005, the entire contents of which are incorporated herein by reference.  
     BACKGROUND  
      1. Field  
      Embodiments of the present invention relate to an information processing device and a method for controlling a viewing angle and outputting a video signal to an external display.  
      2. Description of the Related Art  
      In recent years, liquid crystal display devices have been widely used as display device for notebook type computers, monitors or the like. Improvements in viewing angle dependency of the liquid crystal display device have progressed and the viewing angle with the same level as that of a CRT has been achieved for the liquid crystal display device.  
      However, it is important for a display device, mainly for the use of a mobile terminal, etc., to allow a user to view displayed items from the front direction and to make the display device hard to be viewed from the obliquely front direction. This is because, when confidential documents or the like are prepared or read in a public place and the like, the display device intends to prevent persons other than the user from viewing displayed documents or the like. Hence, the display device is structured to allow the user located in front of the display device to read or write a personal mail without caring about the surroundings.  
      As for a technique to control the viewing angle, a technique using a liquid crystal panel (hereinafter, referred to as a “control filter”) is disclosed (refer to Jpn. Pat. Appln. KOKAI Publication No. 2004-133334). In the technique described in the aforementioned patent document, when the control filter is turned on, a blocking pattern is viewed from the obliquely front direction to protect information on a screen such as a text. Further, even when the control filter is operated, the manner of being viewed from the front is not changed. When the control filter is turned off, the user can view the screen with an original viewing angle of an image display panel for displaying images.  
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       FIG. 1  is an exemplary perspective view showing an example of a schematic configuration of a computer as an information processing device and an external display regarding a first embodiment of the present invention;  
       FIG. 2  is an exemplary view showing an example of an arrangement relationship between a liquid crystal display (LCD) and a privacy filter regarding the first embodiment;  
       FIG. 3A  and  FIG. 3B  are exemplary views explaining examples of viewing angle control by the privacy filters, respectively;  
       FIG. 4  is an exemplary block diagram showing an example of a circuit configuration of the computer regarding the first embodiment of the present invention;  
       FIG. 5  is an exemplary view showing a setting screen to inhibit a video to be automatically output outward when the privacy filter is driven;  
       FIG. 6  is an exemplary flowchart showing a procedure of processing capable of inhibiting the video to be output outward when the privacy filter is driven; and  
       FIG. 7  is an exemplary perspective view showing an example of a schematic configuration of the computer as the information processing device, a docking station as an expansion unit and the external display regarding the first embodiment of the first invention.  
    
    
     DETAILED DESCRIPTION  
      Hereinafter, embodiments of the present invention will be described with reference to the drawings.  
       FIG. 1  is an exemplary view showing an example of a computer as an information processing device regarding a first embodiment of the present invention. Of course, the information processing device may be any other device including, but not limited or restricted to a cellular telephone, personal digital assistant or the like.  
      A computer  10  comprises a computer main body  12  and a display unit  14 . An LCD  16  being a display panel and a privacy filter  17  are incorporated in the display unit  14 .  
      The computer  10  can output a video signal to an external display  200  to display a video thereon.  
      The privacy filter  17  is, as shown in  FIG. 2 , a viewing angle control filter that is mounted on an image display surface of the LCD  16 . The privacy filter  17  may be mounted on a surface on an opposite side of the image display surface of the LCD  16 . The computer  10  can use the privacy filter  17  by mounting it within the display unit  14 . According to one embodiment of the invention, privacy filter  17  has a polarizer on a panel surface, such as an organic EL panel, a liquid crystal panel and others.  
      The display unit  14  is attached to a hinge (support unit)  18  disposed at an end on a depth side of the main body  12  so as to vary rotatably between a closing position to cover an upper face of the main body  12  and an opening position to expose the upper face of the main body  12 .  
      The main body  12  has a thin box-shaped housing, and a central part of an upper face of the housing is provided with a keyboard  20  used for an input device. A palm rest is formed on an upper face of a housing part on near side of the main body  12 . An almost central part of the palm rest is provided with a touch pad  22  used for another input device, a scroll button  24  and a touch pad control button  26 . A power button  28  and a privacy filter button  30  to turn on/off a power source of the main body  12  are arranged on the upper face of the housing part on the depth side of the main body  12 .  
       FIG. 3A  and  FIG. 3B  show exemplary screen viewing angles when the privacy filters  17  are mounted on the LCDs  16 , respectively.  FIG. 3A  illustrates the states of the display screen (from left oblique to right oblique side) when no voltage is applied to the privacy filter  17 . In contrast,  FIG. 3B  shows three states of the display screen when a voltage is applied to the privacy filter  17 .  
      More specifically, as shown within  FIG. 3A  and  FIG. 3B , the left screen indicates how the display screen would be viewed from left oblique side. The central screen image indicates how the display screen would be viewed from front side, and the right screen indicates the screen image as viewed from right oblique side respectively.  
      As mentioned above, in a state where no voltage is applied, the computer  10  displays the same screen as that displayed even when the screen is viewed from the left or right oblique side.  
      In contrast, in a state where voltage is applied, the computer  10  produces the same screen as that displayed when the screen is viewed from the front side. However, when the screen is viewed from the left or right oblique side, a blacken part is generated in response to an area disposed on an orientation film to block the display on an LCD device. By displaying such a block figure, the computer  10  makes recognition of the screen from an obliquely lateral direction more difficult and can prevent other persons from reading material displayed on the screen.  
      Next, an example of a system configuration of the computer  10  will be described by referring to  FIG. 4 .  
      The computer  10  includes, as shown in  FIG. 4 , a CPU  102 , a north bridge  104 , a main memory  114 , a graphics controller  108  as output means, a south bridge  106 , a basic input output system (BIOS)-ROM  120 , a hard disk drive (HDD)  126 , an embedded controller/keyboard controller (EC/KBC) IC  124 , or the like.  
      The CPU  102  is a processor disposed in order to control operations of the computer  10  and executes an operation system (OS) and a variety of application programs loaded into the main memory  114  from the HDD  126 .  
      The CPU  102  loads a system BIOS stored in the BIOS-ROM  120  then executes it. The system BIOS is a program to control hardware.  
      The north bridge  104  is a bridge device to connect between a local bus of the CPU  102  and the south bridge  106 . A memory controller to control access to the main memory  114  is also incorporated in the north bridge  104 . The north bridge  104  also has a function of performing a communication with the graphics controller  108  via an accelerated graphics port (AGP) bus, etc.  
      The graphics controller  108  is a display controller to control the LCD  16  used as a display monitor of the computer  10 . The graphics controller  108  has a video memory (VRAM) and generates a video signal to form a display image to be displayed on the LCD  16  from display data drawn in the VRAM by an OS/application program. The video signal generated by the graphics controller  108  is output to a line.  
      The graphics controller  108  can further output the video signal to the external display  200  connected to any one of an RGB connector  131 , a DVI  132 , an S-Video connector  133  and a D-terminal  134 . When the external display  200  is connected to any one of the RGB connector  131 , DVI  132 , S-Video connector  133  and D-terminal  134 , the setting whether or not the graphics controller  108  outputs the video signal to the external display  200  is registered in ExtMon output setting  120 B in the BIOS-ROM  120 . A switch  128  is provided between the RGB connector  131  and the graphics controller  108  to make it possible to control on and off of a video signal output. An instruction from a video BIOS can control the output of the video signal from the graphics controller  108  to the DVI connector  132 , S-Video connector  133  and D-terminal  134 .  
      The graphics controller  108  can output the video signal to at least one of the LCD  16  and the external displays connected to the connectors  131  to  134 .  
      The EC/KBC IC (filter control unit)  124  controls the touch pad  22 , scroll button  24 , and touch pad control button  26  and also functions as a controller to control the driving of the privacy filter  17 . According to one embodiment of the invention, the EC/KBC IC  124  is a one-chip microcomputer to monitor and control a variety of devices (peripheral device, sensor, power supply circuit, etc.) regardless of a system state of the computer  10 .  
      Operations of the privacy filter button  30  by a user makes the EC/KBC IC  124  switch on/off a drive signal to the privacy filter  17 . The EC/KBC IC  124  notifies a driving state of the privacy filter  17  to the system BIOS. The system BIOS enables (drives) or disables (does not drive) a privacy filter driving flag (PF driving flag)  161  in the main memory  114  in accordance with the driving state of the privacy filter  17 .  
      When the external display  200  is connected in a state of driving of the privacy filter  17 , the computer  10  can inhibit output of the video signal to the external display  200 . A setting window to set this inhibition is displayed as shown in  FIG. 5 . This setting is displayed though a manner in which a PF utility (PF Util.)  140  stored in the HDD  126  is loaded into the main memory  114  and is executed by the CPU  102 .  
      By putting a check mark into a check box  171  shown in  FIG. 5 , the computer  10  can inhibit the output of the video signal to the external display  200  in driving the privacy filter  17 . This setting is registered in ExtMon/PF non-driving setting  120 A in the BIOS-ROM  120  as shown in  FIG. 4 .  
      Next to this, a procedure of processing capable of inhibiting the output of the video signal to the external display  200  in driving the privacy filter  17  will be described with reference to the flowchart in  FIG. 6 .  
      As generally shown in  FIG. 6 , the IO controller  127  of  FIG. 4  first determines whether or not the external display  200  is connected to any one of the RGB connector  131 , DVI  132 , S-Video connector  133  and D-terminal  134  (block S 11 ). If the external display  200  is not connected (No, in block S 11 ), the IO controller  127  determines whether or not the external display is connected, at specified timing (block S 11 ).  
      If the external display  200  is connected (Yes, in block S 11 ), the IO controller  127  notifies to the EC/KBC IC  124  the fact that the external display  200  has been connected. The EC/KBC IC  124  refers to the ExpMon output setting  120 B to determine whether or not it is set to output the video signal to the external display  200  (block S 12 ).  
      If the ExpMon output setting  120 B is enabled and it is set to output the video signal to the external display  200  (Yes, in block S 12 ), the EC/KBC IC  124  refers to the ExtMon/PF non-driving setting  120 A to determine whether or not it is set not to output the video signal to the external display  200  when the privacy filter  17  is driven (block S 13 ).  
      If the ExtMon output setting  120 B is enabled, if the privacy filter  17  is driving and when it is set not to output the video signal to the external display  200  (Yes, in block S 13 ), the EC/KBC IC  124  determines whether or not the privacy filter has been driven by referring to the privacy filter driving flag  114 A (block S 14 ).  
      If the ExtMon output setting  120 B is disabled and when EC/KBC IC  124  is set not to output the video signal to the external display  200  (No, in block S 12 ), or when the privacy filter  17  is driven (Yes, in block S 14 ), the EC/KBC IC  124  operates as an inhibit means to inhibit the video signal to be output via the external output terminal (block S 15 ). The EC/KBC IC  124  turns off the switch  128  inserted between, for example, the RGB connector  131  and graphics controller  108  so as not to output the video signal from the RGB connector  131 . Moreover, the EC/KBC IC  124  instructs the video BIOS so as not to output the video signal to the DVI connector  132 , S-Video connector  133  and D-terminal  134 . The video BIOS instructs the graphics controller  108  so as not to supply the video signal to the external output terminal.  
      When the ExtMon/PF non-driving setting  120 A of  FIG. 4  is disabled (No, in block S 13 ) and when the privacy filter flag is disabled (No, in block S 14 ), the EC/KBC IC  124  outputs the video signal to the external display  200  connected to any one of the RGB connector  131 , DVI  132 , S-Video connector  133  and D-terminal  134 .  
      As mentioned above, the driving of the privacy filter  17  can enhance the confidentiality of the information by inhibiting the video signal to be input to the external display  200 . The computer  10  can simplify operations of the user by controlling the output from the external display  200  in response to the driving state of the privacy filter  17 .  
      As shown in  FIG. 7 , the computer  10  can optionally output the video signal to the external display  200  via a docking station  300 . Even in such a case, the IO controller  127  may detect whether or not the external display  200  is connected to the docking station  300  in the block S 11 . As like the foregoing description, when the IO controller  127  detects the connection of the external display  200  to the docking station  300 , the computer  10  may determine whether the video signal should be or not be output to the external display  200  connected to the docking station  300  in accordance with the ExtMon output setting  120 B of  FIG. 4 , ExtMon/PF non-driving setting  120 A of  FIG. 4  and PF driving flag  114 A of  FIG. 4 .  
      Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.