Patent Publication Number: US-2007097020-A1

Title: Display device

Description:
TECHNICAL FIELD  
      The present invention relates to a display device, and especially relates to a display device with a digital interface and a display method for use in the display device.  
     BACKGROUND ART  
      A display device which has a digital interface and carries out display by processing a digital signal is used. The display device may be used with a PC (personal computer), or may be used with CE (consumer electronics) equipment. The CE equipment supplies a digital image signal to the display device. Typical CE equipment is an STB (set top box for a digital broadcast) and a DVD player. The display device which is provided with the digital interface corresponding to an input from the PC (hereinafter called PC equipment) or the CE equipment is desired.  
      The display device equipped with the digital interface often sends display specifications information to a host device. One example of the display specifications information is EDID (extended display identification data). The EDID includes the resolution of the display device, the information of a scan signal, a frame rate, a maker identifier, and an identifier of the display device. Referring to the EDID, the host device generates a digital signal in a format suited to the specifications of the display device. Such a function is generally called plug-and-play function.  
      Compatibility between EDID for the PC equipment and EDID for the CE equipment is not always ensured. The display device, to which the PC equipment or the CE equipment is connected, has to have the EDID for the CE equipment and the EDID for the PC equipment in accordance with the specifications of the host device (PC equipment/CE equipment). If the display device outputs proper EDID to the host device, the display device can obtain a proper digital signal (image signal) from the host device.  
       FIG. 1  of the accompanying drawings shows a display device (conventional display device) which supplies proper EDID to a host device, when a user operates a manual switch. The conventional display device includes a display device input section  110 , a controller  120 , and a display section (not shown). The display device input section  110  is connected to the controller  120 . The controller  120  is connected to the display section.  
      The display device input section  110  includes a receiver section  116 , a memory section for the CE equipment EDID  103 , a memory section for the PC equipment EDID  104 , memory shift switches  105  and  106 , a manual switch  107 , an analog video input processing section  108 , an analog PC input processing section  109 , analog video input terminals  111  and  112 , analog PC input terminals  113  and  114 , and a digital input terminal  115 . The receiver section  116  has a receiver module for a contents protection system  101 , and a receiver module for digital transmission  102 . The controller  120  has a display signal processor  121  and a display controller  122 .  
      The analog video input processing section  108  is connected to the analog video input terminals  111  and  112  and the display signal processing section  121 . A host device (not shown) is connected to the analog video input terminal  111 . The host device is connected to the analog video input terminal  112 .  
      The analog PC input processing section  109  is connected to the analog PC input terminals  113  and  114  and the display signal processing section  121 . The host device is connected to the analog PC input terminal  113 . The host device is connected to the analog PC input terminal  114 .  
      The receiver section  116  (the receiver module for the contents protection system  101  and the receiver module for digital transmission  102 ) is connected to the digital input terminal  115  and the display signal processing section  121 . The digital input terminal  115  corresponds to the above-mentioned interface. The host device (CE equipment or PC equipment; not shown) is connected to the digital input terminal  115 .  
      The EDID for the CE equipment is stored in the memory section for the CE equipment EDID  103 . The EDID for the PC equipment is stored in the memory section for the PC equipment EDID  104 .  
      The memory shift switch  105  is connected to the digital input terminal  115 , the receiver section  116 , the memory section for the CE equipment EDID  103 , and the memory section for the PC equipment EDID  104 . By switching the memory shift switch  105 , either the memory section for the CE equipment EDID  103  or the memory section for the PC equipment EDID  104  is connected to the digital input terminal  115 . The memory shift switch  106  is also connected to the digital input terminal  115 , the receiver section  116 , the memory section for the CE equipment EDID  103 , and the memory section for the PC equipment EDID  104 . By switching the memory shift switch  106 , either the memory section  103  or the memory section  104  is connected to the digital input terminal  115 . These memory shift switches  105  and  106  are connected to a data line and a clock line, respectively.  
      The user can operate the manual switch  107  to switch the memory shift switches  105  and  106 . When the user operates the manual switch  107 , connection is made between the memory section for the CE equipment EDID  103  and the digital input terminal  115 , or connection is made between the memory section for the PC equipment EDID  104  and the digital input terminal  115 .  
      The display signal processing section  121  is connected to the display section (not shown). The display control section  122  is connected to the display signal processing section  121 . The display signal processing section  121  selects one display signal from among an analog video signal supplied from the analog video input processing section  108 , an analog PC signal supplied from the analog PC input processing section-  109 , a digital video signal supplied from the receiver section  101 , and a digital PC signal supplied from the second receiver section  102 . Then, the display signal processing section  121  subjects the selected display signal to proper signal processing, and feeds a processed signal to the display section. The display control section  122  carries out various setups so that the display signal processing section  121  can perform the proper signal processing.  
      When the user utilizes the host device and the analog video input terminal  111 , an analog video signal is supplied from the host device to the analog video input processing section  108  through the analog video input terminal  111 . The analog signal (analog video signal) is supplied from the analog video input processing section  108  connected to the analog video input terminal  111  to the display signal processing section  121 . Then, the display signal processing section  121  generates an image signal for displaying the analog video signal on the display section, and supplies the image signal to the display section.  
      When the user uses the host device and the analog video input terminal  112 , an analog video signal is sent from the host device to the analog video input processing section  108  through the analog video input terminal  112 . The analog signal (analog video signal) is sent from the analog video input processing section  108  connected to the analog video input terminal  112  to the display signal processing section  121 . Then, the display signal processing section  121  generates an image signal for displaying the analog video signal on the display section, and supplies the image signal to the display section.  
      When the user uses the host device and the analog PC input terminal  113 , an analog PC signal is supplied from the host device to the analog PC input processing section  109  through the analog PC input terminal  113 . The analog signal (analog PC signal) is transferred from the analog PC input processing section  109  connected to the analog PC input terminal  113  to the display signal processing section  121 . Then, the display signal processing section  121  generates an image signal for displaying the analog PC signal on the display section, and supplies the image signal to the display section.  
      When the user uses the host device and the analog PC input terminal  114 , an analog PC signal is supplied from the host device to the analog PC input processing section  109  through the analog PC input terminal  114 . The analog signal (analog PC signal) is supplied from the analog PC input processing section  109  connected to the analog PC input terminal  114  to the display signal processing section  121 . Then, the display signal processing section  121  generates an image signal for displaying the analog PC signal on the display section, and transfers the image signal to the display section.  
      When the user uses the host device (CE equipment) and the digital input terminal  115 , the user operates the manual switch  107  to connect the digital input terminal  115  to the memory section for the CE equipment EDID  103 . The receiver section corresponding to the contents protection system  101  is used, when the digital input terminal  115  is connected to the memory section  103  through the memory shift switches  105  and  106 . When the host device (CE equipment) is connected to the digital input terminal  115 , the host device and the receiver section  101  carry out key authentication to each other. When the keys are authenticated, the CE equipment refers to the CE equipment EDID stored in the memory section  103 , and supplies a digital video signal to the digital input terminal  115  as a digital signal suited to the specifications of the conventional display device. The digital signal (digital video signal) is supplied from the CE equipment to the receiver section  101  through the digital input terminal  115 .  
      The digital video signal from the CE equipment is encoded on the basis of the contents protection system. When broadcasting a digital image, a contents protection function is sometimes used to protect a copyright on contents. For example, HDCP (high bandwidth digital protection) suited for a DVI (digital visual interface) is used for the contents protection. To protect the contents, the digital signal is encoded and transmitted between the CE equipment and the conventional display device. The receiver section corresponding to the contents protection system  101  decodes the encoded digital video signal.  
      The digital signal (digital video signal) is supplied from the receiver section  101  connected to the digital input terminal  115  to the display signal processing section  121 . The display signal processing section  121  generates an image signal for displaying the digital video signal on the display section, and supplies the image signal to the display section.  
      When the user uses the host device (PC equipment) and the digital input terminal  115 , the user operates the manual switch  107  to connect the digital input terminal  115  to the memory section for the PC equipment EDID  104 . The receiver section for digital transmission  102  is used, when the digital input terminal  115  is connected to the memory section  104  through the memory shift switches  105  and  106 . When the host device (PC equipment) is connected to the digital input terminal  115 , the host device refers to the PC equipment EDID stored in the memory section  104 , and outputs a digital PC signal to the digital input terminal  115  as a digital signal suited to the specifications of the conventional display device.  
      The digital signal (digital PC signal) is supplied from the PC equipment to the receiver section  102  through the digital input terminal  115 . The digital signal (digital PC signal) is introduced from the receiver section  102  connected to the digital input terminal  115  to the display signal processing section  121 . The display signal processing section  121  generates an image signal for displaying the digital PC signal on the display section, and outputs the image signal to the display section.  
      When the user uses the CE equipment (host device) and the digital input terminal  115 , the user has to switch the manual switch  107  in order to supply the CE equipment EDID to the conventional display device. If the user forgets to switch the manual switch  107 , the proper digital signal (image signal) cannot be obtained from the CE equipment. When the user uses the PC equipment and the digital input terminal  115 , the user has to switch the manual switch  107  in order to supply the PC equipment EDID to the conventional display device. If the user forgets to switch the manual switch  107 , the proper digital signal (image signal) cannot be obtained from the PC equipment. Thus, a display device which can obtain a proper digital signal from the host device is desired. A display device which can always select proper display specifications information is desired, when a user uses the host device and a digital input terminal.  
      Japanese Patent Application Kokai (Laid-Open) No. 2001-175230 discloses a display device which displays an image on the basis of a group of signals introduced from a host. This display device has determination means, a plurality of storage means, and output means. The determination means determines the interface format of the host. The storage means store display specifications information on a connected-interface-format basis. The output means supplies the specifications information corresponding to the interface format concerned, from the storage means to the host on the basis of a determination result of the determination means.  
      Japanese Patent Kokai No. 2004-102067 discloses an image display device which can operate with a DDC (display data channel). This image display device has a single nonvolatile memory for the DDC, and control means. The control means writes EDID data of an input image signal, into the nonvolatile memory. This EDID data is selected from a plurality of EDED data for various types of image signal, on the basis of information indicating the type of input image signal.  
      When the display device has the single digital input terminal  115  and a plurality of analog input terminals ( 111  to  114 ), as shown in  FIG. 1 , the display signal processing section  121  has to select one of the input terminals, and accept an image signal (display signal) from the selected input terminal. The selection of the input terminal is also carried out on the basis of a command from the user. Specifically, when the user designates “video input” or “RGB input” by use of an operation button or the like, the display control section  122  controls the display signal processing section  121  so that the display signal processing section  121  selects the display signal supplied from the input terminal designated by the command.  
      A display device which can automatically select an input terminal and switch EDID without imposing a burden on a user is desired. When a display device is a digital device such as a liquid crystal display and a plasma display, it is predicted that demand for the display device equipped with a digital interface will increase in the future. Demand for a digital display device such as the plasma display will probably expand by solving the above described problems.  
     SUMMARY OF THE INVENTION  
      One object of the present invention is to provide a display device which can obtain a proper display signal from a host device.  
      Another object of the present invention is to provide a display device which can certainly select proper display specifications information, when a user uses the host device and a digital input terminal.  
      Still another object of the present invention is to provide a display device which reduces a burden on the user so that the display device becomes easier for a user to use.  
      According to one aspect of the present invention, there is provided a display device that includes a plurality of input terminals to receive a plurality of display signals. The input terminals have a digital input terminal. The display device also includes a display signal processing section which selects one of the display signals received at the input terminals, a first memory section which stores first display specifications information, a second memory section which stores second display specifications information, and a memory shift switch which connects the first or second memory section to the digital input terminal. The display device also includes a display control section which controls the operation of the display signal processing section and the memory shift switch. The first and second display specifications information is specifications information for the display signals which are introduced to the digital input terminal. The display control section carries out a “first operation,” in which the display control section controls the display signal processing section so as to select the display signal corresponding to the first display specifications information, and controls the memory shift switch so as to connect the first memory section to the digital input terminal. The display control section carries out a “second operation,” in which the display control section controls the display signal processing section so as to select the display signal corresponding to the second display specifications information, and controls the memory shift switch so as to connect the second memory section to the digital input terminal.  
      According to the present invention, the selection of the input terminal by the display signal processing section is made in conjunction with the switching of the memory shift switch. Therefore, a burden on a user is reduced.  
      This display device further includes an operation section which the user operates. The operation section is connected to the display control section. The operation section has at least one input selection switch which is used by the user to select at least one of the input terminals. The display control section carries out at least one of the “first operation” and the “second operation” in accordance with the operation of the at least one input selection switch by the user.  
      In this display device, the input terminals may further include at least one analog video input terminal to receive an analog video signal and at least one analog PC input terminal to receive an analog PC signal. The operation section has a first input selection switch for selecting either the digital input terminal or the at least one analog video input terminal, and a second input selection switch for selecting either the digital input terminal or the at least one analog PC input terminal.  
      The display control section controls the display signal processing section so as to select the display signal from either the digital input terminal or the at least one analog video input terminal, in accordance with the operation of the first input selection switch by the user. Also, the display control section controls the display signal processing section so as to select the display signal from either the digital input terminal or the at least one analog PC input terminal, in accordance with the operation of the second input selection switch by the user. When the display signal from the digital input terminal is selected in accordance with the operation of the first input selection switch by the user, the display control section carries out the “first operation.” When the display signal from the digital input terminal is selected in accordance with the operation of the second input selection switch by the user, the display control section carries out the “second operation.” 
      In the display device of the present invention, the operation section may be connected to the display control section by radio.  
      According to the present invention, as described above, when the user uses the host device and the digital input terminal, a digital input selection signal is generated in accordance with operation by the user, so that proper display specifications information is selected. Thus, according to a display method of the present invention, it is possible to certainly select the proper display specifications information, when the user uses the host device and the digital input terminal. Because the proper display specifications information is selected, the host device can refer to the proper display specifications information and supply a digital signal suited to the specifications of the display signal to a digital image input terminal. Therefore, according to the display method of the present invention, it is possible to obtain the proper digital signal from the host device.  
      In the display device according to the present invention, the first display specifications information is, for example, EDID (extended display identification data) of consumer electronics equipment and the second display specifications information is, for example, EDID of a personal computer.  
      According to another aspect of the present invention, there is provided a display device that includes a plurality of input terminals, a display signal processing section, a first memory section which stores EDID for video, a second memory section which stores EDID for a PC, a memory shift switch, and an input selection switch which selects one of the input terminals The input terminals include one digital input terminal which receives a digital display signal, at least one analog video input terminal which receives an analog video signal, and at least one analog PC input terminal which receives an analog PC signal. The display signal processing section selects one of the input terminals, and carries out signal processing on a display signal supplied from the selected input terminal to display the display signal on the display section in a format suited to the display section. The memory shift switch connects the digital input terminal to the first or second memory section. At this time, the memory shift switch is switched in accordance with a selection result by the input selection switch, and the display signal processing section determines the display signal to be displayed on the display section.  
      According to still another aspect of the present invention, there is provided a display method for use with a display device. The display device has a plurality of input terminals including a digital input terminal to receive display signals, a first memory section to store first display specifications information, and a second memory section to store second display specifications information. This display method includes: (A) selecting the digital input terminal from the input terminals, when a user selects the first or second display specifications information; (B) connecting the first memory section to the digital input terminal when the first display specifications information is selected, and connecting the second memory section to the digital input terminal when the second display specifications information is selected; and (C) displaying the display signal, which is supplied from the selected digital input terminal and suited to the first display specifications information, when the first display specifications information is selected, and displaying the display signal, which is sent from the selected digital input terminal and suited to the second display specifications information, when the second display specifications information is selected.  
      In this display method, the first display specifications information is EDID of consumer electronics equipment, and the second display specifications information is EDID of a personal computer.  
      According to yet another aspect of the present invention, there is provided a display method that includes the steps of making a user select one input from a plurality of inputs including a digital input, making the user select one digital equipment group from a plurality of digital equipment groups when the user has selected the digital input, connecting a memory section which stores display specifications information of the selected digital equipment group to the digital input terminal, and displaying a display signal which is suited to the display specifications information supplied from the input terminal.  
      As described above, the display device of the present invention can obtain the proper display signal from the host device.  
      Also, the display device of the present invention can always select the proper display specifications information, when the user uses the host device and the digital input terminal.  
      Furthermore, the display device of the present invention reduces a burden on the user, and becomes easier for the user to use. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  shows the structure of a general display device (conventional technology);  
       FIG. 2  shows the structure of a display device according to the present invention (first to fourth embodiments);  
       FIG. 3  is a diagram showing CE equipment EDID which is stored in a memory section of the display device according to the present invention (first to fourth embodiments);  
       FIG. 4  is a diagram showing PC equipment EDID which is stored in another memory section of the display device according to the present invention (first to fourth embodiments);  
       FIG. 5  illustrates another structure of the display device according to the present invention (first to fourth embodiments);  
       FIG. 6  illustrates the structure of an operation section (first and second embodiments);  
       FIG. 7  is a flowchart showing the operation of the display device according to the present invention (first and second embodiments);  
       FIG. 8  is a flowchart showing PC input selection processing performed by the display device of the present invention (first embodiment);  
       FIG. 9  is a flowchart showing video input selection processing performed by the display device of the present invention (first embodiment);  
       FIG. 10  is a flowchart showing PC input selection processing performed by the display device of the present invention (second embodiment);  
       FIG. 11  is a flowchart showing video input selection processing performed by the display device of the present invention (second embodiment);  
       FIG. 12  is a diagram showing the structure of an operation section (third and fourth embodiments);  
       FIG. 13  is a flowchart showing the operation of the display device according to the present invention (third and fourth embodiments);  
       FIG. 14  is a flowchart showing processing when an RGB button is pressed, which is performed by the display device according to the present invention (third embodiment);  
       FIG. 15  is a flowchart showing processing when a video button is pressed, which is performed by the display device according to the present invention (third embodiment);  
       FIG. 16  is a flowchart of processing when the RGB button is pressed, which is performed by the display device according to the present invention (fourth embodiment); and  
       FIG. 17  is a flowchart of processing when the video button is pressed, which is performed by the display device according to the present invention (fourth embodiment). 
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION  
      The best mode for implementing a display device according to the present invention will be hereinafter described with reference to the accompanying drawings.  
     First Embodiment  
       FIG. 2  is a diagram showing the structure of a display device  50  according to a first embodiment of the present invention. The display device  50  includes a display device input section  10 , a controller  20 , a display section  30 , and an operation section  40 . The display device input section  10  is connected to the controller  20 . The controller  20  is connected to the display section  30  and the operation section  40 . The display section  30  is, for example, a plasma display or a liquid crystal display.  
      The display device input section  10  is connected to a host device (not illustrated) outputting a digital signal, or a host device (not illustrated) outputting an analog signal. The display device input section  10  has a digital interface for connecting to the host device outputting the digital signal, and an analog interface for connecting to the host device outputting the analog signal. The host device outputting the digital signal is, for example, CE equipment (consumer electronics equipment; digital equipment group) or PC equipment (personal computer; digital equipment group). The digital interface is, for example, a DVI (digital visual interface). The CE equipment is, for example, an STB (set top box for digital broadcast) or a DVD player.  
      When the CE equipment is connected to the digital interface, the CE equipment supplies a digital video signal to the digital interface. When the PC equipment is connected to the digital interface, the PC equipment supplies a digital PC signal to the digital interface.  
      The display device input section  10  has a receiver section  16 , a memory section for CE equipment EDID  3 , a memory section for PC equipment EDID  4 , memory shift switches  5  and  6 , an analog video input processing section  8 , an analog PC input processing section  9 , analog video input terminals  11  and  12 , analog PC input terminals  13  and  14 , and a digital input terminal  15 . The receiver section  16  includes a receiver for a contents protection system  1  and a receiver for digital transmission  2 . The controller  20  has a display signal processing section  21  and a display control section  22 . The display control section  22  is a microcomputer.  
      The analog video input processing section  8  is connected to the analog video input terminals  11  and  12  and the display signal processing section  21 . The analog video input terminal  11  corresponds to the analog interface, and a host device (not shown) is connected to the analog video input terminal  11 . The analog video input terminal  12  corresponds to the analog interface, and the host device is connected to the analog video input terminal  12 .  
      The analog PC input processing section  9  is connected to the analog PC input terminals  13  and  14  and the display signal processing section  21 . The analog PC input terminal  13  corresponds to the analog interface, and the host device is connected to the analog PC input terminal  13 . The analog PC input terminal  14  corresponds to the analog interface, and the host device is connected to the analog PC input terminal  14 .  
      The receiver section  16  (the receivers  1  and  2 ) is connected to the digital input terminal  15  and the display signal processing section  21 . The digital input terminal  15  corresponds to the digital interface, and the CE equipment (host device) or the PC equipment (host device) is connected to the digital input terminal  15 .  
      The CE equipment and the PC equipment have different display specifications from each other. In the memory section for the CE equipment EDID  3 , EDID (extended display identification data) for the CE equipment is stored. The CE equipment EDID is display specifications information, which indicates the specifications of the display device  50  when the CE equipment is connected to the digital input terminal  15 . The CE equipment EDID is information which includes at least one of the resolution of the display device  50  (display section  30 ), scan-signal-related information, a frame rate, a maker identifier (a vendor code) for identifying a maker, and an identifier (serial number) for identifying the display device  50  when the digital video signal from the CE equipment is displayed on the display device  50  (display section  30 ) (see  FIG. 3 ). The scan-signal-related information of the CE equipment EDID includes a frequency of the scan signal when the CE equipment displays the digital video signal on the display device  50  (display section  30 ).  
      In the memory section for PC equipment EDID  4 , EDID for the PC equipment is stored. The PC equipment EDID is display specifications information, which indicates the specifications of the display device  50  when the PC equipment is connected to the digital input terminal  15 . The PC equipment EDID is information which includes at least one of the resolution of the display device  50  (display section  30 ), scan-signal-related information, a frame rate, a maker identifier (a vendor code), and an identifier (serial number) of the display device  50  (see  FIG. 4 ) when the digital PC signal from the PC equipment is displayed on the display device  50  (display section  30 ). The scan-signal-related information of the PC equipment EDID includes a frequency of the scan signal when the PC equipment displays the digital PC signal on the display device  50  (display section  30 ).  
      The memory shift switch  5  is connected to the digital input terminal  15 , the receiver section  16 , the memory section for CE equipment EDID  3 , and the memory section for PC equipment EDID  4 . By switching the memory shift switch  5 , either the memory section  3  or the memory section  4  is connected to the digital input terminal  15 . The memory shift switch  6  is also connected to the digital input terminal  15 , the receiver section  16 , the memory section  3 , and the memory section  4 . By switching the memory shift switch  6 , either the memory section  3  or the memory section  4  is connected to the digital input terminal  15 . The memory shift switches  5  and  6  are connected to a data line and a clock line, respectively.  
      The display signal processing section  21  of the controller  20  is connected to the display section  30 . The display control section  22  of the controller  20  is connected to the operation section  40 , the display signal processing section  21 , and the memory shift switches  5  and  6 .  
      The display signal processing section  21  selects one display signal from among the analog video signal supplied from the analog video input processing section  8 , the analog PC signal supplied from the analog PC input processing section  9 , the digital video signal supplied from the receiver section  1 , and the digital PC signal supplied from the receiver section  2 . Then, the display signal processing section  21  subjects the selected display signal to proper signal processing, and supplies a processed signal to the display section  30 .  
      The display control section  22  carries out various setups so that the display signal processing section  21  can carry out the proper signal processing. Specifically, the display control section  22  supplies an input terminal selection signal to the display signal processing section  21 . The display signal processing section  21  selects one of the input terminals ( 11  to  15 ) in accordance with the input terminal selection signal, and receives a display signal from the selected input terminal.  
      In this embodiment, the display control section  22  switches the memory shift switches  5  and  6 . Specifically, the display control section  22  causes the display signal processing section  21  to select the digital video signal from the receiver section  1 , and outputs a control signal for selecting the memory section  3  to the memory shift switches  5  and  6 . Accordingly, the memory shift switcher  5  and  6  are switched, and hence the digital input terminal  15  is connected to the CE equipment EDID memory  3 . Alternatively, the display control section  22  causes the display signal processing section  21  to select the digital PC signal from the receiver section  2 , and outputs a control signal for selecting the memory section  4  to the memory shift switches  5  and  6 . In this case, the memory shift switches  5  and  6  are switched such that the digital input terminal  15  is connected to the memory section  4 . In other words, the display control section  22  according to this embodiment not only causes the display signal processing section  21  to select a single proper input terminal out of the input terminals, but also perform the switching of the memory shift switches  5  and  6 .  
      When using the host device and the analog video input terminal  11 , a user operates the operation section  40 . The display control section  22  outputs a first analog video input terminal selection signal to the display signal processing section  21  in accordance with the operation of the operation section  40  by the user. In this embodiment, the display device  50  carries out “VIDEO 1” selection processing.  
      In the “VIDEO 1” selection processing, the display signal processing section  21  selects the analog video input terminal  11  out of the analog video input terminals  11  and  12 , the analog PC input terminals  13  and  14 , and the digital input terminal  15  in accordance with the first analog video input terminal selection signal. When the host device is connected to the selected analog video input terminal  11 , the host device supplies the analog video signal (i.e., the analog signal) to the analog video input processing section  8  through the analog video input terminal  11 . The analog signal (analog video signal) is supplied from the analog video input processing section  8  connected to the analog video input terminal  11  into the display signal processing section  21 . The display signal processing section  21  generates an image signal for displaying the analog video signal on the display section  30 , and outputs the image signal to the display section  30 .  
      When using the host device and the analog video input terminal  12 , the user operates the operation section  40 . The display control section  22  supplies a second analog video input terminal selection signal to the display signal processing section  21  in accordance with the operation of the operation section  40  by the user. In this embodiment, the display device  50  carries out “VIDEO 2” selection processing.  
      In the “VIDEO 2” selection processing, the display signal processing section  21  selects the analog video input terminal  12  out of the analog video input terminals  11  and  12 , the analog PC input terminals  13  and  14 , and the digital input terminal  15  in accordance with the second analog video input terminal selection signal. When the host device is connected to the selected analog video input terminal  12 , the host device supplies the analog video signal (i.e., the analog signal) to the analog video input processing section  8  through the analog video input terminal  12 . The analog signal (analog video signal) is issued from the analog video input processing section  8  connected to the analog video input terminal  12  into the display signal processing section  21 . The display signal processing section  21  generates an image signal for displaying the analog video signal on the display section  30 , and supplies the image signal to the display section  30 .  
      When using the host device and the analog PC input terminal  13 , the user operates the operation section  40 . The display control section  22  supplies a first analog PC terminal selection signal to the display signal processing section  21  in accordance with the operation of the operation section  40  by the user. In this embodiment, the display device  50  carries out “RGB (red, green, and blue) 1” selection processing.  
      In the “RGB 1” selection processing, the display signal processing section  21  selects the analog PC input terminal  13  out of the analog video input terminals  11  and  12 , the analog PC input terminals  13  and  14 , and the digital input terminal  15  in accordance with the first analog PC terminal selection signal. When the host device is connected to the selected analog PC input terminal  13 , the host device supplies the analog PC signal (i.e., the analog signal) to the analog PC input processing section  9  through the analog PC input terminal  13 . The analog signal (analog PC signal) is supplied from the analog PC input processing section  9  connected to the analog PC input terminal  13  into the display signal processing section  21 . The display signal processing section  21  generates an image signal for displaying the analog PC signal on the display section  30 , and supplies the image signal to the display section  30 .  
      When using the host device and the analog PC input terminal  14 , the user operates the operation section  40 . The display control section  22  supplies a second analog PC terminal selection signal to the display signal processing section  21  in accordance with the operation of the operation section  40  by the user. Then, the display device  50  carries out “RGB 2” selection processing.  
      In the “RGB 2” selection processing, the display signal processing section  21  selects the analog PC input terminal  14  out of the analog video input terminals  11  and  12 , the analog PC input terminals  13  and  14 , and the digital input terminal  15  in accordance with the second analog PC terminal selection signal. When the host device is connected to the selected analog PC input terminal  14 , the host device supplies the analog PC signal (i.e., the analog signal) to the analog PC input processing section  9  through the analog PC input terminal  14 . The analog signal (analog PC signal) is supplied from the analog PC input processing section  9  connected to the analog PC input terminal  14  into the display signal processing section  21 . The display signal processing section  21  generates an image signal for displaying the analog PC signal on the display section  30 , and supplies the image signal to the display section  30 .  
      When using the host device (CE equipment; not shown) and the digital input terminal  15 , the user operates the operation section  40 . The display control section  22  generates a digital video input selection signal to the display signal processing section  21  in accordance with the operation of the operation section  40  by the user. Furthermore, the display control section  22  supplies a control signal to the memory shift switches  5  and  6  to select the CE equipment EDID memory  3 . Then, the display device  50  simultaneously carries out “RGB 3/VIDEO 3 (video input mode)” selection processing and CE equipment EDID memory selection processing.  
      In the “RGB 3/VIDEO 3 (video input mode)” selection processing, the display signal processing section  21  selects the digital input terminal  15  out of the analog video input terminals  11  and  12 , the analog PC input terminals  13  and  14 , and the digital input terminal  15  in accordance with the digital video input selection signal.  
      In the CE equipment EDID memory selection processing, the memory shift switches  5  and  6  are switched in accordance with the control signal from the display control section  22 , so that the memory section  3  is connected to the digital input terminal  15 . The receiver section for the contents protection system  1  is used, when the CE equipment EDID memory selection processing is carried out (when the digital input terminal  15  is connected to the memory section  3  through the memory shift switches  5  and  6 ). When the CE equipment (not illustrated) is connected to the selected digital input terminal  15 , the CE equipment and the receiver section  1  carry out key authentication to each other. When the keys are authenticated, the CE equipment refers to the CE equipment EDID stored in the memory section  3 , and sends a digital video signal to the digital input terminal  15  as a digital signal suited to the specifications of the display device  50 .  
      In the “RGB 3/VIDEO 3 (video input mode)” selection processing, the digital signal (digital video signal) is sent from the CE equipment to the receiver section  1  through the digital input terminal  15 . The digital video signal from the CE equipment is encoded on the basis of the contents protection system. When broadcasting a digital image, a contents protection function may be utilized to protect the copyright of contents. For instance, HDCP (high bandwidth digital protection) corresponding to the DVI (digital visual interface) may be utilized. To protect the contents, the digital signal which is encoded by use of the HDCP is transmitted between the CE equipment and the display device  50 . The receiver section for the contents protection system  1  decodes the encoded digital video signal.  
      The digital signal (digital video signal) is issued from the receiver section  1  connected to the digital input terminal  15  into the display signal processing section  21 . The display signal processing section  21  generates an image signal for displaying the digital video signal on the display section  30 , and sends the image signal to the display section  30 .  
      When using the host device (PC equipment; not shown) and the digital input terminal  15 , the user operates the operation section  40 . The display control section  22  sends a digital PC input selection signal to the display signal processing section  21  in accordance with the operation of the operation section  40  by the user. Furthermore, the display control section  22  sends a control signal to the memory shift switches  5  and  6  to select the PC equipment EDID memory  4 . The display device  50  simultaneously carries out “RGB 3/VIDEO 3 (PC input mode)” selection processing and PC equipment EDID memory selection processing.  
      In the “RGB 3/VIDEO 3 (PC input mode)” selection processing, the display signal processing section  21  selects the digital input terminal  15  out of the analog video input terminals  11  and  12 , the analog PC input terminals  13  and  14 , and the digital input terminal  15  in accordance with the digital PC input selection signal.  
      In the PC equipment EDID memory selection processing, the memory shift switches  5  and  6  are switched in accordance with the control signal from the display control section  22 , so that the memory section  4  is connected to the digital input terminal  15 . The receiver section for digital transmission  2  is used, when the PC equipment EDID memory selection processing is carried out (when the digital input terminal  15  is connected to the memory section  4  through the memory shift switches  5  and  6 ). When the PC equipment is connected to the selected digital input terminal  15 , the PC equipment refers to the PC equipment EDID stored in the memory section  4 , and outputs a digital PC signal to the digital input terminal  15  as a digital signal suited to the specifications of the display device  50 .  
      In the “RGB 3/VIDEO 3 (PC input mode)” selection processing, the digital signal (digital PC signal) is transferred from the PC equipment to the receiver section  2  through the digital input terminal  15 . The digital signal (digital PC signal) is issued from the receiver section  2  connected to the digital input terminal  15  into the display signal processing section  21 . The display signal processing section  21  generates an image signal for displaying the digital PC signal on the display section  30 , and outputs the image signal to the display section  30 .  
      Conventionally, when a user uses a host device (PC equipment or CE equipment) and the digital input terminal  115 , the user has to switch the manual switch  107  in order to make the host device (PC equipment or CE equipment) refer to proper EDID (EDID for PC equipment or EDID for CE equipment). Accordingly, if the user forgets to switch the manual switch  107 , it is impossible to obtain a proper digital signal from the host device (PC equipment or CE equipment). Also, the user has to conduct another operation, i.e., make a display signal processing section  121  select one of the input terminals ( 111  to  115 ).  
      In the display device  50  according to the first embodiment of the present invention, the selection of the input terminal ( 11  to  15 ) by the display signal processing section  21  is conducted in conjunction with the switching of the memory shift switches  5  and  6 . Specifically, when the user uses the host device (PC equipment or CE equipment) and the digital input terminal  15 , the user operates the operation section  40 . In accordance with the user&#39;s operation, the display control section  22  sends the input selection signal (digital video input selection signal) to the display signal processing section  21 , and also sends the control signal for selecting the CE equipment EDID to the memory shift switches  5  and  6 . Alternatively, the display control section  22  outputs the input selection signal (digital PC input selection signal) to the display signal processing section  21 , and also outputs the control signal for selecting the PC equipment EDID to the memory shift switches  5  and  6 . Therefore, according to the display device  50  of the first embodiment of the present invention, it is possible to certainly select the proper EDID, when the user uses the host device (PC equipment or CE equipment) and the digital input terminal  15 . Furthermore, since the selection of the EDID is performed in conjunction with the selection of the input terminal ( 11  to  15 ), a burden on the user is reduced.  
      According to the display device  50  of the first embodiment of the present invention, the proper EDID is selected so that the host device (PC equipment or CE equipment) can supply the digital signal suited to the specifications of the display device  50  to the digital image input terminal  15  with reference to the proper EDID. Thus, the display device  50  according to the first embodiment of the present invention can obtain the proper digital signal from the host device (PC equipment or CE equipment).  
       FIG. 5  is a diagram showing a modification to the display device  50  according to the first embodiment of the present invention. The operation section  40  is provided in a main body of the display device  50  in the foregoing description, but may be provided in a remote control terminal  45  as shown in  FIG. 5 . In this case, the display device  50  is provided with a receiver section  46  instead of the operation section  40 , and the remote control terminal  45  is provided with the operation section  40 . The remote control terminal  45  communicates with the main body (display device  50 ) in a wired or wireless manner. The receiver section  46  connected to the display control section  22  supplies a signal to the display control section  22  in accordance with operation from the operation section  40  by the user.  
       FIG. 6  is a diagram showing the structure of the operation section  40 . The operation section  40  has a “PC INPUT SELECTION” button  41  and a “VIDEO INPUT SELECTION” button  42 . The display control section  22  has a PC input counter (not shown) and a video input counter (not shown).  
       FIG. 7  is a flowchart showing the operation of the display device  50  according to the first embodiment of the present invention. Ever time the user presses the “PC INPUT SELECTION” button  41  of the operation section  40  (step S 1 —YES), the display control section  22  increments a count number i of the PC input counter by  1 , and clears a count number j of the video input counter (step S 2 ). Then, the display device  50  carries out PC input selection processing (step S 3 ).  
      Every time the user presses the “VIDEO INPUT SELECTION” button  42  of the operation section  40  (step S 1 —NO and S 4 —YES), the display control section  22  clears the count number i of the PC input counter, and increments the count number j of the video input counter by 1 (step S 5 ). In this case, the display device  50  carries out video input selection processing (step S 6 ).  
       FIG. 8  is a flowchart of the PC input selection processing (step S 3 ) performed by the display device  50  according to the first embodiment of the present invention. When the count number i of the PC input counter is  1 , i.e., when the user has pressed the “PC INPUT SELECTION” button  41  of the operation section  40  once (step S 11 —YES), the display control section  22  sends the first analog PC terminal selection signal to the display signal processing section  21 . Then, the display device  50  carries out the “RGB 1” selection processing (step S 12 ).  
      In the “RGB 1” selection processing (step S 12 ), the display signal processing section  21  selects the analog PC input terminal  13  out of the analog video input terminals  11  and  12 , the analog PC input terminals  13  and  14 , and the digital input terminal  15  in accordance with the first analog PC terminal selection signal. Accordingly, when the analog PC signal is supplied from the analog PC input processing section  9  connected to the analog PC input terminal  13  into the display signal processing section  21 , the display signal processing section  21  can generate the image signal for displaying the analog PC signal on the display section  30  and outputs the image signal to the display section  30 . The display signal processing section  21  displays, for example, “RGB 1” in a predetermined position of the display section  30  so as to inform the user that an analog PC input image from the analog PC input terminal  13  is displayed.  
      When the count number i of the PC input counter is  2 , in other words, when the user has pressed the “PC INPUT SELECTION” button  41  of the operation section  40  once more (twice) (step S 11 —NO and S 13 —YES), the display control section  22  outputs the second analog PC terminal selection signal to the display signal processing section  21 . Then, the display device  50  carries out the “RGB 2” selection processing (step S 14 ).  
      In the “RGB 2” selection processing (step S 14 ), the display signal processing section  21  selects the analog PC input terminal  14  out of the analog video input terminals  11  and  12 , the analog PC input terminals  13  and  14 , and the digital input terminal  15  in accordance with the second analog PC terminal selection signal. Accordingly, when the analog PC signal is introduced from the analog PC input processing section  9  connected to the analog PC input terminal  14  into the display signal processing section  21 , the display signal processing section  21  can generate the image signal for displaying the analog PC signal on the display section  30  and outputs the image signal to the display section  30 . The display signal processing section  21  displays, for example, “RGB 2” in a predetermined position of the display section  30 , for the purpose of informing the user that an analog PC input image from the analog PC input terminal  14  is displayed.  
      When the count number i of the PC input counter is  3 , in other words, when the user has pressed the “PC INPUT SELECTION” button  41  of the operation section  40  once more (three times) (step S 11 —NO, S 13 —NO, and S 15 —YES), the display control section  22  supplies the digital PC input selection signal to the display signal processing section  21 , and supplies the control signal to the memory shift switches  5  and  6 . Then, the display device  50  simultaneously carries out the “RGB 3/VIDEO 3 (PC input mode)” selection processing (step S 16 ) and the PC equipment EDID memory selection processing (step S 17 ).  
      In the “RGB 3/VIDEO 3 (PC input mode)” selection processing (step S 16 ), the display signal processing section  21  selects the digital input terminal  15  out of the analog video input terminals  11  and  12 , the analog PC input terminals  13  and  14 , and the digital input terminal  15  in accordance with the digital PC input selection signal.  
      In the PC equipment EDID memory selection processing (step S 17 ), the memory shift switches  5  and  6  are switched in accordance with the control signal, and the digital input terminal  15  is connected to the memory section  4 . When the PC equipment is connected to the selected digital input terminal  15 , the PC equipment refers to the PC equipment EDID stored in the memory section  4 , and outputs the digital PC signal to the digital input terminal  15  as the digital signal suited to the specifications of the display device  50 .  
      In the “RGB 3/VIDEO 3 (PC input mode)” selection processing (step S 16 ), the digital PC signal is introduced from the receiver section  2  connected to the digital input terminal  15  into the display signal processing section  21 . The display signal processing section  21  generates the image signal for displaying the digital PC signal on the display section  30 , and supplies the image signal to the display section  30 . The display signal processing section  21  displays, for example, “RGB 3/VIDEO 3 (PC input mode)” in a predetermined position of the display section  30 , for the purpose of informing the user that a digital PC input image from the digital input terminal  15  is displayed.  
      When the count number i of the PC input counter is  4 , in other words, when the user has pressed the “PC INPUT SELECTION” button  41  of the operation section  40  once more (four times) (step S 11 —NO, S 13 —NO, and S 15 —NO), the display control section  22  sets the count number i of the PC input counter at  1  (step S 18 ), and carries out the step S 11 .  
       FIG. 9  is a flowchart showing the video input selection processing (step S 6 ) performed by the display device  50  according to the first embodiment of the present invention. When the count number j of the video input counter is  1 , in other words, when the user has pressed the “VIDEO INPUT SELECTION” button  42  of the operation section  40  once (step S 21 —YES), the display control section  22  sends the first analog video terminal selection signal to the display signal processing section  21 . Then, the display device  50  carries out the “VIDEO 1” selection processing (step S 22 ).  
      In the “VIDEO 1” selection processing (step S 22 ), the display signal processing section  21  selects the analog video terminal  11  out of the analog video input terminals  11  and  12 , the analog PC input terminals  13  and  14 , and the digital input terminal  15  in accordance with the first analog video terminal selection signal. Accordingly, when the analog video signal is supplied from the analog video input processing section  8  connected to the analog video terminal  11  into the display signal processing section  21 , the display signal processing section  21  can generate the image signal for displaying the analog video signal on the display section  30  and sends the image signal to the display section  30 . The display signal processing section  21  displays, for example, “VIDEO 1” in a predetermined position of the display section  30 , for the purpose of informing the user that an analog video input image from the analog video input terminal  11  is displayed.  
      When the count number j of the video input counter is  2 , in other words, when the user has pressed the “VIDEO INPUT SELECTION” button  42  of the operation section  40  once more (twice) (step S 21 —NO and S 23 —YES), the display control section  22  supplies the second analog video terminal selection signal to the display signal processing section  21 . Then, the display device  50  carries out the “VIDEO 2” selection processing (step S 24 ).  
      In the “VIDEO 2” selection processing (step S 24 ), the display signal processing section  21  selects the analog video terminal  12  out of the analog video input terminals  11  and  12 , the analog PC input terminals  13  and  14 , and the digital input terminal  15  in accordance with the second analog video terminal selection signal. Accordingly, when the analog video signal is supplied from the analog video input processing section  8  connected to the analog video terminal  12  into the display signal processing section  21 , the display signal processing section  21  can generate the image signal for displaying the analog video signal on the display section  30  and supplies the image signal to the display section  30 . Then, the display signal processing section  21  displays, for example, “VIDEO 2” in a predetermined position of the display section  30 , for the purpose of informing the user that an analog video input image from the analog video input terminal  12  is displayed.  
      When the count number j of the video input counter is  3 , in other words, when the user has pressed the “VIDEO INPUT SELECTION” button  42  of the operation section  40  once more (three times) (step S 21 —NO, S 23 —NO, and S 25 —YES), the display control section  22  supplies the digital video input selection signal to the display signal processing section  21 , and supplies the control signal to the memory shift switches  5  and  6 . The display device  50  simultaneously carries out the “RGB 3/VIDEO 3 (video input mode)” selection processing (step S 26 ) and the CE equipment EDID memory selection processing (step S 27 ).  
      In the “RGB 3/VIDEO 3 (video input mode)” selection processing (step S 26 ), the display signal processing section  21  selects the digital input terminal  15  out of the analog video input terminals  11  and  12 , the analog PC input terminals  13  and  14 , and the digital input terminal  15  in accordance with the digital video input selection signal.  
      In the CE equipment EDID memory selection processing (step S 27 ), the memory shift switches  5  and  6  are switched in accordance with the control signal, and the digital input terminal  15  is connected to the memory section  3 . When the CE equipment is connected to the selected digital input terminal  15 , the CE equipment refers to the CE equipment EDID stored in the memory section  3 , and outputs the digital video signal to the digital input terminal  15  as the digital signal suited to the specifications of the display device  50 .  
      In the “RGB 3/VIDEO 3 (video input mode)” selection processing (step S 26 ), the digital video signal is issued from the receiver section  1  connected to the digital input terminal  15  into the display signal processing section  21 . The display signal processing section  21  generates the image signal for displaying the digital video signal on the display section  30 , and outputs the image signal to the display section  30 . Then, the display signal processing section  21  displays, for example, “RGB 3/VIDEO 3 (video input mode)” in a predetermined position of the display section  30 , for the purpose of informing the user that a digital video input image from the digital input terminal  15  is displayed.  
      When the count number j of the video input counter is  4 , in other words, when the user has pressed the “VIDEO INPUT SELECTION” button  42  of the operation section  40  once more (four times) (step S 21 —NO, S 23 —NO, and S 25 —NO), the display control section  22  sets the count number j of the video input counter at  1  (step S 28 ), and carries out the step S 21 .  
      The display control section  22  carries out the step S 18  and proceeds to the step S 11 , when the user presses the “PC INPUT SELECTION” button  41  of the operation section  40  four times. The display control section  22  may carry out the step S 18  and proceed to the step S 11 , when the user presses the “PC INPUT SELECTION” button  41  of the operation section  40  for a certain (predetermined) period of time. The display control section  22  carries out the step S 28  and shifts to the step S 21 , when the user presses the “VIDEO INPUT SELECTION” button  42  of the operation section  40  four times. The display control section  22  may carry out the step S 28  and shift to the step S 21 , when the user presses the “VIDEO INPUT SELECTION” button  42  of the operation section  40  for a certain (predetermined) period of time.  
      In the PC input selection processing (step  3 ), the order of carrying out the “RGB 1” selection processing (step S 12 ), the “RGB 2” selection processing (step S 14 ), the “RGB 3/VIDEO  3  (PC input mode)” selection processing (step S 16 ), and the PC equipment EDID memory selection processing (step S 17 ) is fixed. It should be noted, however, that this order is just an example for carrying out the invention, and is flexibly changeable.  
      In the video input selection processing (step S 6 ), the order of carrying out the “VIDEO 1” selection processing (step S 22 ), the “VIDEO 2” selection processing (step S 24 ), the “RGB 3/VIDEO 3 (video input mode)” selection processing (step S 26 ), and the CE equipment EDID memory selection processing (step S 27 ) is fixed. It should be noted, however, that this order is just an example for carrying out the invention, and is flexibly changeable.  
      In the step S 2 , the count number j of the video input counter is cleared. It should be noted that the count number j may be held; not cleared. In the step S 5 , likewise, the count number i of the PC input counter is cleared, but the count number i may be held.  
      According to the display device  50  of the first embodiment of the present invention, the selection of the input terminal ( 11  to  15 ) is made in conjunction with the selection of the EDID memory ( 3  and  4 ). Thus, a burden on the user is reduced. Therefore, it is possible to provide the display device  50  which is easy for the user to use. The user only has to operate the “PC INPUT SELECTION” button  41  or the “VIDEO INPUT SELECTION” button  42  of the operation section  40 , and does not have to operate the manual switch. If the user operates the operation section  40  (“PC INPUT SELECTION” button  41  or “VIDEO INPUT SELECTION” button  42 ) on the remote controller  45 , the user can control the display device  50  from a remote place, so that a burden on the user is further reduced. Also, when the proper EDID is selected, the kind of the input signal is displayed on the display section  30  of the display device  50 . Therefore, it is possible to provide the display device  50  which is much easier for the user to use.  
      According to the display device  50  of the first embodiment of the present invention, when the user uses the host device (PC equipment or CE equipment) and the digital input terminal  15 , the display control section  22  selects the PC equipment EDID in accordance with the operation by the user, or the display control section  22  selects the CE equipment EDID in accordance with the operation by the user. Thus, the display device  50  according to the first embodiment of the present invention can certainly select the proper EDID, when the user uses the host device (PC equipment or CE equipment) and the digital input terminal  15 .  
      The display device  50  of the first embodiment of the present invention selects the proper EDID so that the host device (PC equipment or CE equipment) can refer to the proper EDID and send the digital signal suited to the specifications of the display device  50  to the digital image input terminal  15 . Therefore, the display device  50  of the first embodiment of the present invention can obtain the proper digital signal from the host device (PC equipment or CE equipment).  
     Second Embodiment  
      The PC input selection processing (step S 3 ) performed by the display device  50  according to a second embodiment of the present invention is different from the first embodiment. Specifically, pressing the “PC INPUT SELECTION” button  41  of the operation section  40  switches the digital PC input image into the digital video input image. The video input selection processing (step S 6 ) performed by the display device  50  according to the second embodiment of the present invention is also different from the first embodiment. Specifically, pressing the “VIDEO INPUT SELECTION” button  42  of the operation section  40  switches the digital video input image into the digital PC input image. In the following description of the display device  50  according to the second embodiment of the present invention, description overlapping the first embodiment is omitted.  
       FIG. 10  is a flowchart showing the PC input selection processing (step S 3 ) performed by the display device  50  according to the second embodiment of the present invention. When the count number i of the PC input counter is  4 , i.e., when the user has pressed the “PC INPUT SELECTION” button  41  of the operation section  40  once more (four times) (step S 11 —NO, S 13 —NO, S 15 —NO, and S 19 —YES), the display device  50  simultaneously carries out “RGB 3/VIDEO 3 (video input mode)” selection processing (step S 26 ) and CE equipment EDID memory selection processing (step S 27 ), which are the same as those in the first embodiment.  
      When the count number i of the PC input counter is  5 , i.e., when the user has pressed the “PC INPUT SELECTION” button  41  of the operation section  40  once more (five times) (step S 11 —NO, S 13 —NO, S 15 —NO, and S 19 —NO), the display control section  22  sets the count number i of the PC input counter at  1  (step S 18 ), and carries out step S 11 .  
       FIG. 11  illustrates a flowchart of the video input selection processing (step S 6 ) carried out by the operation of the display device  50  according to the second embodiment of the present invention.  
      When the count number j of the PC input counter is  4 , i.e., when the user has pressed the “VIDEO INPUT SELECTION” button  42  of the operation section  40  once more (four times) (step S 21 —NO, S 23 —NO, S 25 —NO, and S 29 —YES), the display device  50  simultaneously carries out “RGB 3/VIDEO 3 (PC input mode)” selection processing (step S 16 ) and PC equipment EDID memory selection processing (step S 17 ), which are the same as those in the first embodiment.  
      When the count number j of the PC input counter is  5 , i.e., when the user has pressed the “VIDEO INPUT SELECTION” button  42  of the operation section  40  once more (five times) (step S 21 —NO, S 23 —NO, S 25 —NO, and S 29 —NO), the display control section  22  sets the count number j of the video input counter at  1  (step S 28 ), and carries out the step S 21 .  
      The display control section  22  carries out the step S 18  and advances to the step S 11 , when the user has pressed the “PC INPUT SELECTION” button  41  of the operation section  40  five times. It should be noted, however, that the display control section  22  may carry out the step S 18  and advance to the step S 11 , when the user presses the “PC INPUT SELECTION” button  41  of the operation section  40  for a certain (predetermined) period of time. The display control section  22  carries out the step S 28  and proceeds to the step S 21 , when the user has pressed the “VIDEO INPUT SELECTION” button  42  of the operation section  40  five times. It should be noted, however, that the display control section  22  may carry out the step S 28  and proceed to the step S 21 , when the user presses the “PC INPUT SELECTION” button  42  of the operation section  40  for a certain (predetermined) period of time.  
      In the PC input selection processing (step S 3 ), the order of carrying out the “RGB 1” selection processing (step S 12 ), the “RGB 2” selection processing (step S 14 ), the “RGB 3/VIDEO 3 (PC input mode)” selection processing (step S 16 ), the PC equipment EDID memory selection processing (step S 17 ), the “RGB 3/VIDEO 3 (video input mode)” selection processing (step S 26 ), and the CE equipment EDID memory selection processing (step S 27 ) is fixed. It should be noted that this order is just an example for carrying out the invention, and is flexibly changeable.  
      In the video input selection processing (step S 6 ), the order of carrying out the “VIDEO 1” selection processing (step S 22 ), the “VIDEO 2” selection processing (step S 24 ), the “RGB 3/VIDEO 3 (video input mode)” selection processing (step S 26 ), the CE equipment EDID memory selection processing (step S 27 ), the “RGB 3/VIDEO 3 (PC input mode)” selection processing (step S 16 ), and the PC equipment EDID memory selection processing (step S 17 ) is fixed. The order is just an example for carrying out the invention, and is flexibly changeable.  
      According to the display device  50  of the second embodiment of the present invention, when the user uses the host device (PC equipment; not shown) and the digital input terminal  15 , the user is only required to operate the “PC INPUT SELECTION” button  41  of the operation section  40 . When the user uses the host device (CE equipment; not shown) and the digital input terminal  15 , the user is only required to operate the “PC INPUT SELECTION” button  41  of the operation section  40  again. When the user uses the host device (CE equipment) and the digital input terminal  15 , the user is only required to operate the “VIDEO INPUT SELECTION” button  42  of the operation section  40 . When the user uses the host device (PC equipment) and the digital input terminal  15 , the user is only required to operate the “VIDEO INPUT SELECTION” button  42  of the operation section  40  again. According to the display device  50  of the second embodiment of the present invention, as described above, the user operates the same button to switch between the PC equipment and the CE equipment. Thus, in addition to the advantage of the first embodiment, a burden on the user is further reduced, and the display device  50  becomes easier for the user to use.  
     Third Embodiment  
      The display device  50  according to a third embodiment of the present invention directly switches among the analog PC input image from the analog PC input terminal  13 , the analog PC input image from the analog PC input terminal  14 , the digital PC input image from the digital input terminal  15 , the analog video input image from the analog video input terminal  11 , the analog video input image from the analog video input terminal  12 , and the digital video input image from the digital input terminal  15 . In the following description of the display device  50  according to the third embodiment of the present invention, description overlapping the first and second embodiments is omitted.  
       FIG. 12  is a diagram showing the structure of an operation section  40 . The operation section  40  is provided with an “RGB 1” button  51 , an “RGB 2” button  52 , an “RGB 3” button  53 , a “VIDEO 1” button  61 , a “VIDEO 2” button  62 , and a “VIDEO 3” button  63 , instead of the “PC INPUT SELECTION” button  41  and the “VIDEO INPUT SELECTION” button  42 .  
       FIG. 13  is a flowchart showing the operation of the display device  50  according to the third embodiment of the present invention. When the user presses any “RGB” button out of the “RGB 1” button  51 , the “RGB 2” button  52 , and the “RGB 3” button  53  of the operation section  40  (step S 31 —YES), the display device  50  carries out RGB button-pressed processing (step S 32 ). When the user presses any “VIDEO” button out of the “VIDEO 1” button  61 , the “VIDEO 2” button  62 , and the “VIDEO 3” button  63  of the operation section  40  (step S 31 —NO and S 33 —YES), the display device  50  carries out video button-pressed processing (step S 34 ).  
       FIG. 14  is a flowchart showing the RGB button-pressed processing (step S 32 ) performed by the display device  50  according to the third embodiment of the present invention. When the user presses the “RGB 1” button  51  of the operation section  40  (step S 41 —YES), the display control section  22  sends the first analog PC terminal selection signal to the display signal processing section  21 . Then, the display device  50  carries out the “RGB 1” selection processing which is the same as that of the first embodiment (step S 12 ).  
      When the user presses the “RGB 2” button  52  of the operation section  40  (step S 41 —NO and S 42 —YES), the display control section  22  sends the second analog PC terminal selection signal to the display signal processing section  21 . Then, the display device  50  carries out the “RGB 2” selection processing which is the same as that of the first embodiment (step S 14 ).  
      When the user presses the “RGB 3” button  53  of the operation section  40  (step S 41 —NO, S 42 —NO, and S 43 ), the display control section  22  outputs the digital PC input selection signal to the display signal processing section  21 . Then, the display device  50  simultaneously carries out the “RGB 3/VIDEO 3 (PC input mode)” selection processing (step S 16 ) and the PC equipment EDID memory selection processing (step S 17 ), which are the same as those of the first embodiment.  
       FIG. 15  is a flowchart showing the video button-pressed processing (step S 34 ) performed by the display device  50  according to the third embodiment of the present invention. When the user presses the “VIDEO 1” button  61  of the operation section  40  (step S 51 —YES), the display control section  22  outputs the first analog video terminal selection signal to the display signal processing section  21 . Then, the display device  50  carries out the “VIDEO 1” selection processing which is the same as that of the first embodiment (step S 22 ).  
      When the user presses the “VIDEO 2” button  62  of the operation section  40  (step S 51 —NO and S 52 —YES), the display control section  22  outputs the second analog video terminal selection signal to the display signal processing section  21 . Then, the display device  50  carries out the “VIDEO 2” selection processing which is the same as that of the first embodiment (step S 24 ).  
      When the user presses the “VIDEO 3” button  63  of the operation section  40  (step S 51 —NO, S 52 —NO, and S 53 ), the display control section  22  supplies the digital video input selection signal to the display signal processing section  21 . Then, the display device  50  simultaneously carries out the “RGB 3/VIDEO 3 (video input mode)” selection processing (step S 26 ) and the CE equipment EDID memory selection processing (step S 27 ), which are the same as those of the first embodiment.  
      According to the display device  50  of the third embodiment of the present invention, when the user uses the host device (PC equipment) and the digital input terminal  15 , the user is only required to operate the “RGB 3” button  53  of the operation section  40 . When the user uses the host device (CE equipment) and the digital input terminal  15 , the user is only required to operate the “VIDEO 3” button  63  of the operation section  40 . According to the display device  50  of the third embodiment of the present invention, therefore, when the user switches between the PC equipment and the CE equipment, the display device  50  directly supplies the proper EDID (EDID for PC equipment or EDID for CE equipment) to the host device (PC equipment or CE equipment). Therefore, in addition to the advantage of the first embodiment, a burden on the user is further reduced, and the display device  50  becomes easier for the user to use.  
     Fourth Embodiment  
      The RGB button-pressed processing (step S 32 ) performed by the display device  50  according to a fourth embodiment of the present invention is different from the third embodiment. Specifically, pressing the “RGB 3” button  53  of the operation section  40  switches the digital PC input image into the digital video input image. The video button-pressed processing (step S 34 ) performed by the display device  50  according to the fourth embodiment of the present invention is also different from the third embodiment. Specifically, pressing the “VIDEO 3” button  63  of the operation section  40  switches the digital video input image into the digital PC input image. In the following description of the display device  50  according to the fourth embodiment of the present invention, description overlapping the third embodiment is omitted.  
       FIG. 16  is a flowchart showing RGB button-pressed processing (step S 32 ) carried out by the display device  50  according to the fourth embodiment of the present invention. When the user presses the “RGB 1” button  51  of the operation section  40  (step S 41 —YES), the display control section  22  clears the count number i of the PC input counter and the count number j of the video input counter (step S 44 ), and supplies the first analog PC terminal selection signal to the display signal processing section  21 . Then, the display device  50  carries out the “RGB 1” selection processing which is the same as that of the first embodiment (step S 12 ).  
      When the user presses the “RGB 2” button  52  of the operation section  40  (step S 41 —NO and S 42 —YES), the display control section  22  clears the count number i of the PC input counter and the count number j of the video input counter (step S 45 ), and supplies the second analog PC terminal selection signal to the display signal processing section  21 . Then, the display device  50  carries out the “RGB 2” selection processing which is the same as that of the first embodiment (step S 14 ).  
      When the user presses the “RGB 3” button  53  of the operation section  40  (step S 41 —NO, S 42 —NO, and S 43 ), the display control section  22  increments the count number i of the PC input counter by  1 , and clears the count number j of the video input counter (step S 46 ).  
      When the count number i of the PC input counter is  1 , in other words, when the user presses the “RGB 3” button  53  of the operation section  40  once (step S 47 —YES), the display control section  22  outputs the digital PC input selection signal to the display signal processing section  21 . Then, the display device  50  simultaneously carries out the “RGB 3/VIDEO 3 (PC input mode)” selection processing (step S 16 ) and PC equipment EDID memory selection processing (step S 17 ), which are the same as those of the first embodiment.  
      When the count number i of the PC input counter is  2 , in other words, when the user presses the “RGB 3” button  53  of the operation section  40  once more (twice) (step S 47 —NO and S 48 —YES), the display control section  22  outputs the digital video input selection signal to the display signal processing section  21 . Then, the display device  50  simultaneously carries out the “RGB 3/VIDEO 3 (video input mode)” selection processing (step S 26 ) and the CE equipment EDID memory selection processing (step S 27 ), which are the same as those of the first embodiment.  
      When the count number i of the PC input counter is  3 , in other words, when the user presses the “RGB 3” button  53  of the operation section  40  once more (three times) (step S 47 —NO and S 48 —NO), the display control section  22  sets the count number i of the PC input counter at  1  (step S 49 ), and carries out the step S 47 .  
       FIG. 17  is a flowchart of video button-pressed processing (step S 34 ) carried out by the display device  50  according to the fourth embodiment of the present invention. When the user presses the “VIDEO 1” button  61  of the operation section  40  (step S 51 —YES), the display control section  22  clears the count number i of the PC input counter and the count number j of the video input counter (step S 54 ), and outputs the first analog video terminal selection signal to the display signal processing section  21 . Then, the display device  50  carries out the “VIDEO 1” selection processing which is the same as that of the first embodiment (step S 22 ).  
      When the user presses the “VIDEO 2” button  62  of the operation section  40  (step S 51 —NO and S 52 —YES), the display control section  22  clears the count number i of the PC input counter and the count number j of the video input counter (step S 55 ), and outputs the second analog video terminal selection signal to the display signal processing section  21 . Then, the display device  50  carries out the “VIDEO 2” selection processing which is the same as that of the first embodiment (step S 24 ).  
      When the user presses the “VIDEO 3” button  63  of the operation section  40  (step S 51 —NO, S 52 —NO, and S 53 ), the display control section  22  clears the count number i of the PC input counter, and increments the count number j of the video input counter by  1  (step S 56 ).  
      When the count number j of the video input counter is  1 , in other words, when the user presses the “VIDEO 3” button  63  of the operation section  40  once (step S 57 —YES), the display control section  22  outputs the digital video input selection signal to the display signal processing section  21 . Then, the display device  50  simultaneously carries out the “RGB 3/VIDEO 3 (video input mode)” selection processing (step S 26 ) and the CE equipment EDID memory selection processing (step S 27 ), which are the same as those of the first embodiment.  
      When the count number j of the video input counter is  2 , in other words, the user presses the “VIDEO 3” button  63  of the operation section  40  once more (twice) (step S 57 —NO and S 58 —YES), the display control section  22  outputs the digital PC input selection signal to the display signal processing section  21 . Then, the display device  50  simultaneously carries out the “RGB 3/VIDEO 3 (PC input mode)” selection processing (step S 16 ) and the PC equipment EDID memory selection processing (step S 17 ), which are the same as those of the first embodiment.  
      When the count number j of the video input counter is  3 , in other words, when the user presses the “VIDEO 3” button  63  of the operation section  40  once more (three times) (step S 57 —NO and S 58 —NO), the display control section  22  sets the count number j of the video input counter at  1  (step S 59 ), and carries out the step S 57 .  
      The display control section  22  carries out the step S 49  and proceeds to the step S 47 , when the user presses the “RGB 3” button  53  of the operation section  40  three times. It should be noted that the display control section  22  may carry out the step S 49  and proceed to the step S 47 , when the user presses the “RGB 3” button  53  of the operation section  40  for a certain (predetermined) period of time. The display control section  22  carries out the step S 59  and proceeds to the step S 57 , when the user presses the “VIDEO 3” button  63  of the operation section  40  three times. It should be noted that the display control section  22  may carry out the step S 59  and proceed to the step S 57 , when the user presses the “VIDEO 3” button  63  of the operation section  40  for a certain (predetermined) period of time.  
      The count number j of the video input counter is cleared in the steps S 44 , S 45 , S 46 , S 54 , and S 55  in the foregoing description. It should be noted, however, that the count number j may be held instead of being cleared. The count number i of the PC input counter is cleared in the steps S 44 , S 45 , S 54 , S 55 , and S 56  in the foregoing description. It should be noted, however, that the count number i may be held instead of being cleared.  
      According to the display device  50  of the fourth embodiment of the present invention, when the user uses the host device (PC equipment) and the digital input terminal  15 , the user is only required to operate the “RGB 3” button  53  of the operation section  40 . When the user uses the host device (CE equipment) and the digital input terminal  15 , the user is only required to operate the “RGB 3” button  53  of the operation section  40  again. When the user uses the host device (CE equipment) and the digital input terminal  15 , the user is only required to operate the “VIDEO 3” button  63  of the operation section  40 . When the user uses the host device (PC equipment) and the digital input terminal  15 , the user is only required to operate the “VIDEO 3” button  63  of the operation section  40  again. According to the display device  50  of the fourth embodiment of the present invention, as described above, the user can switch between the PC equipment and the CE equipment by the same buttons. Therefore, in addition to the advantages of the third embodiment, a burden on the user is further reduced, and the display device  50  becomes easier for the user to use.  
      As understood from the foregoing description, the display device  50  of the present invention can obtain the proper display signal from the host device.  
      Also, the display device  50  of the present invention can always select the proper display specifications information, when the user uses the host device and the digital input terminal  15 .  
      Furthermore, the display device  50  of the present invention can reduce a burden on the user, and is easy for the user to use.