Abstract:
A method is adapted for providing privacy to a display device. The display device is adapted to display a normal image that can be viewed in a user area within which a user is situated. The method includes the steps of: a) configuring the display device to generate information of an interference image; b) configuring a display panel of the display device to display the normal image and the interference image; and c) configuring the display device to direct the interference image toward areas outside the user area. Accordingly, the user situated in the user area is able to view the normal image, while a viewer outside the user area is able to view the interference image, thereby achieving a privacy effect.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority of Taiwanese Application No. 099110345, filed on Apr. 2, 2010. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a method for providing privacy to a display device, more particularly to a method that utilizes an interference image to provide privacy to a display device. 
         [0004]    2. Description of the Related Art 
         [0005]    Display devices are widely used in many applications, such as notebook computers, cell phones, digital cameras, personal digital assistants, and so on. When the display devices are used, how to prevent information displayed by the display device from being viewed by other people is a significant problem. 
         [0006]    In a conventional method for providing privacy to a display device, a shield is attached to a display panel of the display device. By virtue of an optical film of the shield, a viewing region of the display panel is limited to a certain area at which a user may see an image displayed by the display panel such that other people situated in other areas outside the certain area may not see the image. Alternatively, the liquid crystal of the display device is controllable to block backlight of the display device such that, aside from an expected area at which an image displayed by the display device is viewable, the image may not be viewed at other areas. It is desirable to provide other methods for providing privacy to a display device. 
       SUMMARY OF THE INVENTION 
       [0007]    Therefore, an object of the present invention is to provide a method for providing privacy to a display device. 
         [0008]    Accordingly, a method of the present invention is adapted for providing privacy to a display device. The display device is adapted to display a normal image that can be viewed in a user area within which a user is situated. The method comprises the steps of: a) configuring the display device to generate information of an interference image; b) configuring a display panel of the display device to display the normal image and the interference image; and c) configuring the display device to direct the interference image toward areas outside the user area. 
         [0009]    Preferably, in step b), a part of picture elements of the display panel of the display device is controllable to operate as display pixels for displaying the normal image, and a remaining part of the picture elements of the display panel is controllable to operate as interference pixels for displaying the interference image. In step c), an optical path control component is configured to direct lights emitted from the interference pixels away from the user area and toward the areas outside the user area such that a viewer situated outside the user area is able to view the interference image. 
         [0010]    Preferably, the optical path control component is configured to block optical paths of the lights emitted from the interference pixels toward the user area and to direct the lights emitted from the interference pixels away from the user area and toward the areas outside the user area. Particularly, the optical path control component is formed with a plurality of light-transmissive parts and a plurality of opaque parts, and a line connecting one of the interference pixels and a corresponding one of the opaque parts extends to the user area. The light-transmissive parts permit passage of lights emitted from the display pixels toward the user area, whereas the opaque parts block passage of the lights emitted from the interference pixels toward the user area. Further, the display device is configured to adjust positions of the light-transmissive parts and the opaque parts of the optical path control component according to a position of the user as detected by a detector of the display device. Particularly, the display device is configured to determine a relative position of the user with respect to the display device via the detector, and to adjust the positions of the light-transmissive parts and the opaque parts of the optical path control component according to the relative position. Therefore, when the user moves, the positions of the light-transmissive parts and the opaque parts are adjusted such that the viewer situated outside the user area continues to view the interference image. 
         [0011]    Alternatively, the optical path control component is configured to refract and direct the lights emitted from the interference pixels toward the areas outside the user area. 
         [0012]    Preferably, in step b), the display panel of the display device is configured to alternately display the normal image and the interference image. In step c), the display device is configured to direct the normal image toward the user area when the display panel displays the normal image, and to direct the interference image toward the areas outside the user area when the display panel displays the interference image such that a viewer situated outside the user area is able to view the interference image. Particularly, for directing the normal image toward the user area and directing the interference image toward the areas outside the user area, a backlight module of the display device includes a first light source configured to project light such that the normal image is directed at least toward the user area, and a second light source configured to project light such that the interference image toward the areas outside the user area. 
         [0013]    Another object of the present invention is to provide a display device with privacy function. 
         [0014]    According to another aspect, a display device of the present invention is adapted for displaying a normal image that can be viewed in a user area within which a user is situated. The display device comprises a display panel, a display control module, and an optical path control component. The display panel includes a plurality of picture elements for image display. The display control module is electrically connected to the display panel, and is operable to generate information of an interference image, to control a part of the picture elements of the display panel to operate as display pixels for displaying the normal image, and to control a remaining part of the picture elements of the display panel to operate as interference pixels for displaying the interference image. The optical path control component is disposed to correspond to the picture elements of the display panel so as to control optical paths of lights emitted from the interference pixels and to direct the lights emitted from the interference pixels toward areas outside the user area. 
         [0015]    Preferably, the display pixels for displaying the normal image and the interference pixels for displaying the interference image are alternately arranged in one of vertical columns, horizontal rows, and an interlaced arrangement. 
         [0016]    Preferably, the optical path control component is a lenticular lens that is disposed on the display panel, and that includes a plurality of first column parts registered with the interference pixels, and a plurality of second column parts registered with the display pixels. The first column parts are configured to refract and direct the lights emitted from the interference pixels toward the areas outside the user area, whereas the second column parts are configured to direct lights emitted from the display pixels toward the user area. 
         [0017]    Preferably, the optical path control component is a liquid crystal shutter disposed in front of and spaced apart from the display panel. The liquid crystal shutter is formed with a plurality of light-transmissive parts permitting passage of lights emitted from the display pixels toward the user area, and a plurality of opaque parts blocking passage of the lights emitted from the interference pixels toward the user area. The display device further comprises a detector and a position-adjusting module. The detector is operable to detect a position of the user. The position-adjusting module cooperates with the detector to determine a relative position of the user with respect to the display device, and is operable to adjust positions of the light-transmissive parts and the opaque parts of the optical path control component according to the relative position so as to permit the passage of the lights emitted from the display pixels toward the user area and to block the passage of the lights emitted from the interference pixels toward the user area. 
         [0018]    Preferably, the optical path control component is a parallax barrier plate disposed in front of and spaced apart from the display panel. The parallax barrier plate is formed with a plurality of light-transmissive parts permitting passage of lights emitted from the display pixels toward the user area, and a plurality of opaque parts blocking passage of the lights emitted from the interference pixels toward the user area. 
         [0019]    According to a further aspect, a display device of this invention is adapted for displaying a normal image that can be viewed in a user area within which a user is situated. The display device comprises a display panel, a backlight module, and a display control module. The display panel is adapted for image display. The backlight module is disposed to correspond in position to the display panel, and includes a first light source and a second light source. The first light source is configured to provide the display panel with light such that an image displayed by the display panel is directed at least toward the user area and is viewable at the user area. The second light source is configured to provide the display panel with light such that the image displayed by the display panel is directed toward and is viewable at areas outside the user area. The display control module is electrically connected to the display panel and the backlight module. The display control module is operable to generate information of an interference image, to control the display panel to alternately display the normal image and the interference image, to turn on the first light source and turn off the second light source when the display panel displays the normal image, and to turn on the second light source and turn off the first light source when the display panel displays the interference image. 
         [0020]    Preferably, the display panel is a liquid crystal panel. 
         [0021]    According to this invention, a user situated within a user area is able to view a normal image and not view an interference image, whereas a viewer situated outside the user area is able to view the interference image, thereby resulting in a privacy effect. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments with reference to the accompanying drawings, of which: 
           [0023]      FIG. 1  is a schematic view for illustrating relationship between positions of a user area relative to a display device implementing a first preferred embodiment of a method for providing privacy according to this invention, and an interference area; 
           [0024]      FIG. 2  is a schematic view for illustrating components of the display device; 
           [0025]      FIG. 3  is a block diagram for illustrating hardware architecture of the display device; 
           [0026]      FIG. 4  is a flow chart for illustrating steps of the method of the first preferred embodiment; 
           [0027]      FIG. 5  is a fragmentary schematic view for illustrating picture elements of a display panel of the display device operating as display pixels and interference pixels; 
           [0028]      FIG. 6  is a fragmentary schematic view for illustrating a function of an optical path control component of the display device; 
           [0029]      FIG. 7  is a fragmentary schematic view for illustrating that positions of light-transmissive parts and opaque parts of the optical path control component are movable when a user moves; 
           [0030]      FIG. 8  is a schematic view for illustrating a display device implementing a second preferred embodiment of a method for providing privacy according to this invention; 
           [0031]      FIG. 9  is a block diagram for illustrating hardware architecture of the display device; 
           [0032]      FIG. 10  is a fragmentary schematic view for illustrating a function of an optical path control component of the display device; 
           [0033]      FIG. 11  is a flow chart for illustrating steps of the method of the second preferred embodiment; 
           [0034]      FIG. 12  is a schematic view for illustrating a display device implementing a third preferred embodiment of a method for providing privacy according to this invention, and for illustrating that an image displayed by the display device is directed toward a user area; 
           [0035]      FIG. 13  is a schematic view for illustrating that an image displayed by the display device is directed toward areas outside the user area; 
           [0036]      FIG. 14  is a block diagram for illustrating hardware architecture of the display device; and 
           [0037]      FIG. 15  is a flow chart for illustrating steps of the method of the third preferred embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0038]    Referring to  FIG. 4 , a first preferred embodiment of a method for providing privacy to a display device is implemented by a display device  1  shown in  FIGS. 1 to 3 . The display device  1  includes a control unit  10 , a backlight module  11 , an optical layer  12 , a display panel  13 , a memory unit  14 , an optical path control component  15 , and a detector  16 . As shown in  FIG. 2 , the backlight module  11 , the optical layer  12  and the display panel  13  are stacked in sequence from rear to front, and the optical path control component  15  is disposed in front of and spaced apart from the display panel  13 . The optical path control component  15  is controlled by the control unit  10  so as to adjust a viewing angle of the display panel  13 . The control unit  10  is operable to read the memory unit  14  and control the display panel  13  to display an image, and is coupled to and cooperates with the detector  16  to adjust the optical path control component  15 . For convenience of the following description, in this embodiment, an area within which a user  400  is situated is defined as a user area  401 , and an area outside the user area  401  is defined as an interference area  402 . Further, the user area  401  and the interference area  402  may move when the user  400  moves. 
         [0039]    The backlight module  11  includes a light-guiding plate  111  and a pair of light sources  112  respectively disposed at opposite sides of light-guiding plate  111 . In this embodiment, the light sources  112  are cold cathode lamps. It should be noted that the backlight module  11  is not limited to this embodiment and may be other types of backlight modules, such as a light-emitting-diode backlight module. The optical layer  12  is disposed on the backlight module  11 , and maybe one of a brightness enhancement film, a prismoidal lens, and a diffusion plate. Further, in other embodiments, the display device  1  may include a plurality of the optical layers  12 , or the optical layer  12  may even be omitted. 
         [0040]    The display panel  13  is disposed on the optical layer  12 , and includes a plurality of picture elements for image display. In this embodiment, the display panel  13  is a liquid crystal panel. However, the display panel  13  may be a plasma panel or an organic light-emitting display panel that do not require the backlight module  11 . The memory unit  14  stores information of a normal image, and provides the control unit  10  with required memory space. In this embodiment, the memory unit  14  is a dynamic random access memory (DRAM). 
         [0041]    Referring to  FIGS. 1 and 3 , the detector  16  is operable to detect a position of the user  400  for determining the user area  401 . In particular, the detector  16  may be a charge-coupled device (CCD) or a CMOS image sensor (CIS), and is adapted to capture an image of the user  400  and to transmit information of the captured image of the user  400  to the control unit  10 . The control unit  10  includes a position-adjusting module  102  electrically connected to the detector  16  and the optical path control component  15 . The position-adjusting module  102  is adapted to receive the information of the image captured by the detector  16 , and to implement image processing for determining a relative position of the user  400  with respect to the display device  1  so as to identify the user area  401  associated with the user  400 . Referring to  FIG. 6 , the optical path control component  15  is formed with a plurality of light-transmissive parts  151  and a plurality of opaque parts  152 , and the position-adjusting module  102  is operable to adjust positions of the light-transmissive parts  151  and the opaque parts  152  according to the relative position of the user  400  in step  701  shown in  FIG. 4 . The function of the optical path control component  15  will be described later. In this embodiment, the control unit is a microprocessor, and the position-adjusting module  102  may be implemented using software. In other embodiments, the control unit  10  and the position-adjusting module  102  may be implemented using electronic circuits. 
         [0042]    The control unit  10  further includes a display control module  101  electrically connected to the memory unit  14  and the display panel  13  as shown in  FIG. 3 . In this embodiment, the display control module  101  may be implemented using software or electronic circuits. The display control module  101  is operable to generate information of an interference image. In step  702  shown in  FIG. 4 , the display control module  101  is operable to control a part of the picture elements of the display panel  13  to operate as display pixels  131  for displaying the normal image according to the information stored in the memory unit  14 , and to control a remaining part of the picture elements of the display panel  13  to operate as interference pixels  132  for displaying the interference image. In particular, as shown in  FIG. 5 , the display control module  101  is operable to set the picture elements in odd vertical columns as the display pixels  131 , and to set the picture elements in the even vertical columns as the interference pixels  132 . That is to say, the picture elements in the odd vertical columns are used for displaying the normal image, and the picture elements in the even vertical columns are used for displaying the interference image. Certainly, the display pixels  131  and the interference pixels  132  may be alternately arranged in horizontal rows or in an interlaced arrangement in other embodiments. 
         [0043]    It should be noted that, in this embodiment, the optical path control component  15  is a liquid crystal shutter formed with the light-transmissive parts  151  and the opaque parts  152  as shown in  FIG. 6 . Particularly, a line connecting one of the interference pixels  132  and a corresponding one of the opaque parts  152  extends to the user area  401 . In step  703  as shown in  FIG. 4 , lights emitted from the interference pixels  132  are blocked by the opaque parts  152 , that is to say, the opaque parts  152  block passage of the lights emitted from the interference pixels  132  toward the user area  401 . Therefore, the interference image will not be directed toward the user area  401 . Furthermore, the light-transmissive parts  151  permit passage of lights emitted from the display pixels  131  toward the user area  401 . Thus, the user  400  situated within the user area  401  may see the normal image but not the interference image, and other people within the interference area  402  may see the interference image and be disturbed thereby. Accordingly, an effect of providing privacy is achieved. 
         [0044]    Additionally, referring to  FIG. 7 , when the position-adjusting module  102  cooperates with the detector  16  to determine that the position of the user  401  has changed, the position-adjusting module  102  is operable to adjust positions of the light-transmissive parts  151  and the opaque parts  152  according to the relative position of the user  400  with respect to the display device  1 . That is to say, the positions of the light-transmissive parts  151  and the opaque parts  152  are adjustable according to the position of the user  400  detected by the detector  16 . Therefore, the light-transmissive parts  151  may still accurately permit the passage of the lights emitted from the display pixels  131  toward the user area  401  and direct the normal image to the user area  401 , and the opaque parts  152  may still block the passage of the lights emitted from the interference pixels  132  toward the user area  401 . As a result, no matter where the user  400  is situated, the user  400  may only see the normal image but not the interference image. Further, since the interference image displayed by the interference pixels  132  is still directed to the interference area  402  outside the user area  401 , the interference image still interferes with the people within the interference area  402  to thereby maintain the effect of providing privacy. Moreover, an ultrasonic detector or an infrared detector may be used for detecting the position of the user  400  so as to determine the relative position of the user  400  with respect to the display device  1  in other embodiments. 
         [0045]    Additionally, the memory unit  14  may be configured to store both the information of the normal image and the information of the interference image such that the display control module  101  is operable to control the display pixels  131  and the interference pixels  132  to display the normal image and the interference image according to the information stored in the memory unit  14 , respectively. Further, the optical path control component  15  may alternatively be a parallax barrier plate. It should be noted that, while the positions of the light-transmissive parts  151  and the opaque parts  152  formed on the liquid crystal shutter are adjustable, the positions of the light-transmissive parts  151  and the opaque parts  152  formed on the parallax barrier plate are not adjustable. 
         [0046]    Referring to  FIG. 11 , a second preferred embodiment of a method for providing privacy to a display device is implemented by a display device  2  shown in  FIGS. 8 to 10 . The display device  2  includes a control unit  20 , a backlight module  21 , an optical layer  22 , a display panel  23 , a memory unit  24 , and an optical path control component  25 . The backlight module  21 , the optical layer  22 , the display panel  23  and the memory unit  24  are similar to the backlight module  11 , the optical layer  12 , the display panel  13  and the memory unit  14  of the display device  1  described in the first preferred embodiment. It should be noted that the optical path control component  25  of the display device  2  of this embodiment is not adjustable, and thus the user area  401  associated with the display device  2  within which the user  400  may see the normal image is immovable. That is to say, a viewing angle of the display device  2  for displaying the normal image is constant. The viewing angle is associated with the user area  401 , and an area outside the viewing angle is the interference area  402 , i.e., a viewing angle of the display device  2  for displaying the interference image. 
         [0047]    Compared with the first preferred embodiment, the control unit  20  of the display device  2  of the second preferred embodiment only includes a display control module  201 . In this embodiment, the control unit  20  is a microprocessor, and the display control module  201  maybe implemented using software or electronic circuits. 
         [0048]    In step  801  of the flowchart shown in  FIG. 11 , the display control module  201  is operable to control apart of the picture elements of the display panel  23  to operate as display pixels  231 , and to control a remaining part of the picture elements of the display panel  23  to operate as interference pixels  232  as shown in  FIG. 10 . Arrangement of the display pixels  231  and the interference pixels  232  is similar to the arrangement of the display pixels  131  and the interference pixels  132  of the first preferred embodiment shown in  FIG. 5 . In particular, the display control module  201  in this embodiment is operable to set the picture elements of the display panel  23  in odd vertical columns as the display pixels  231 , and to set the picture elements of the display panel  23  in the even vertical columns as the interference pixels  232 . 
         [0049]    Referring to  FIG. 10 , the optical path control component  25  in this embodiment is a lenticular lens formed with a plurality of first column parts  251  registered with the interference pixels  232 , and a plurality of second column parts  250  registered with the display pixels  231 . In step  802  of the flowchart shown in  FIG. 11 , the second column parts  250  are configured to direct lights emitted from the display pixels  231  toward the user area  401 , and the first column parts  251  are configured to refract and direct lights emitted from the interference pixels  232  toward the interference area  402 . Optical structure of the optical path control component  25  is configured to refract the lights emitted from the interference pixels  232  and originally directed toward the user area  401 , and to direct the interference image to the interference area  402 . Therefore, the user  400  situated within the user area  401  may only see the normal image, and people situated within the interference area  402  may see the interference image and be disturbed thereby. Accordingly, an effect of providing privacy is achieved. 
         [0050]    Referring to  FIG. 15 , a third preferred embodiment of a method for providing privacy to a display device is implemented by a display device  3  shown in  FIGS. 12 to 14 . The display device  3  includes a control unit  30 , a backlight module  31 , a display panel  32 , and a memory unit  33 . The memory unit  33  in this embodiment is similar to the memory unit  14  of the display device  1  of the first preferred embodiment, and details thereof will be omitted herein for the sake of brevity. 
         [0051]    The display panel  32  is adapted for displaying an image. In this embodiment, the display panel  32  is a liquid crystal panel. The backlight module  31  is stackedly disposed to correspond in position to the display panel  32  so as to provide backlight to the display panel  32  for displaying images. In this embodiment, the backlight module  31  is a directional backlight module, and includes an optical light-guiding plate  311 , a first light source  312  disposed at one side of the optical light-guiding plate  311 , and a second light source  313  disposed at the other side of the optical light-guiding plate  311 . Techniques of the directional backlight module are disclosed in Taiwanese Patent No. I312883, and details thereof will be omitted herein for the sake of brevity. By the design of the optical light-guiding plate  311 , when the first light source  312  is turned on and the second light source  313  is turned off, lights emitted from the display device  3  will be directed toward the user area  401  as shown in  FIG. 12 . When the second light source  313  is turned on and the first light source  312  is turned off, the lights emitted from the display device  3  will be directed toward the interference area  401  as shown in  FIG. 13 . 
         [0052]    Referring to  FIG. 14 , the control unit  30  includes a display control module  301  electrically connected to the memory unit  33 , the display panel  32  and the backlight module  31 . In this embodiment, the control unit  30  is a microprocessor, and the display control module  301  may be implemented using software or electronic circuits. In step  901  of the flowchart shown in  FIG. 15 , the display control module  301  is operable to generate information of an interference image, and to control the display panel  32  to alternately display the normal image and the interference image. Further, in step  902 , when inputting the information of the normal image to the display panel  32  for displaying the normal image, the display control module  301  is operable to control the backlight module  31  to turn on the first light source  312  and turn off the second light source  313  so as to direct the normal image toward the user area  401  as shown in  FIG. 12 . On the other hand, when inputting the information of the interference image to the display panel  32  for displaying the interference image, the display control module  301  is operable to control the backlight module  31  to turn on the second light source  313  and turn off the first light source  312  so as to direct the interference image toward the interference area  402  as shown in  FIG. 13 . Therefore, by directing the interference image toward the interference area  402 , people situated within the interference area  402  will see the interference image and be disturbed thereby, and thus an effect of providing privacy is achieved. 
         [0053]    In summary, the display device  1 ,  2 ,  3  of this invention is adapted to generate the interference image. By the above-mentioned steps and components, the display device  1 ,  2 ,  3  allows the user  400  situated within the user area  401  to see the normal image but not the interference image, and makes people situated within the interference area  402  see the interference image. Therefore, the people situated within the interference area  402  will be disturbed by the interference image to thereby achieve an effect of providing privacy to the display device  1 ,  2 ,  3 . 
         [0054]    While the present invention has been described in connection with what are considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.