Patent Publication Number: US-2022214851-A1

Title: Display device and method for controlling display device

Description:
TECHNICAL FIELD 
     The present invention relates to a display device and a method for controlling a display device. 
     BACKGROUND ART 
     A high-speed input switching function of a display device is for performing input switching at a high speed by taking in video signals of two inputs, displaying a screen of one input, setting a screen of the other input to be not displayed, and performing switching between the displayed screen and the not-displayed screen using a screen composition technology. In other words, in a two-screen display such as picture in picture (PinP), video signals of two inputs are taken into a memory, one input is displayed on a main screen, and the other input is displayed while reduced in size as a sub screen and is combined with the main screen. Here, for example, by setting the sub screen to be not displayed and interchanging the main screen and the sub screen, high-speed input switching can be performed. 
     In addition, a display device configuring a multiple displays by aligning a plurality of the display devices has a function of being able to output an input video signal to a display device of a next stage through relay. In other words, an external output non-correspondence video input terminal, an external output correspondence video input terminal, and a video output terminal are disposed in such a display device. In addition, in such a display device, a reception unit used for switching of a video signal from another video input terminal and supporting output of a video to the outside is disposed. In a case in which a display device is independently used, a video signal does not need to be transmitted to another display device, and thus an external output non-correspondence video input terminal is used. In a case in which a multiple-display is configured, a video signal from the previous stage is input to an external output correspondence video input terminal. Then, the mode of the reception unit is set to a mode for relaying a video signal, and a video signal from the previous stage is output from a video output terminal through the reception unit and is transmitted to a display device of the next stage. 
     In addition, Patent Literature 1 states that, in an environment in which a plurality of display devices are connected, display timings of a plurality of connected monitors are synchronized with other when switching between sources is performed. 
     CITATION LIST 
     Patent Literature 1 
     
         
         Japanese Unexamined Patent Application, First Publication No. H11-234595 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     As described above, in a display device having a function of being able to output an input video signal to a display device of the next stage through relay, an external output non-correspondence video input terminal and an external output correspondence video input terminal are disposed. In such a display device, when switching between a video signal from the external output non-correspondence video input terminal and a video signal from the external output correspondence video input terminal is performed using the technology of the high-speed input switching function described above, there is a problem in that a deviation in timing temporarily occurs. 
     In other words, an external output correspondence video signal is input through the reception unit used for switching between video signals and supporting output of a video to the outside. When a video signal is input from the external output non-correspondence input terminal, the reception unit is set to a mode in which a video signal is not output from the video output terminal. When the input is switched from the external output non-correspondence input terminal to the external output correspondence input terminal, the reception unit is switched to a mode in which a video signal is output from the external output terminal. At this time, the reception unit temporarily stops output of a signal at the time of mode switching. In accordance with this, a deviation in timing occurs. 
     In view of the problems described above, an object of the present invention is to provide a display device and a method for controlling a display device preventing occurrence of disturbance in timing at the time of performing input switching using a high-speed input switching function. 
     Solution to Problem 
     A display device according to one aspect of the present invention includes: a reception unit configured to receive a video signal input from an external output correspondence input terminal and a timing signal corresponding to the video signal; a video processing unit configured to perform processing on a video signal input from an external output non-correspondence input terminal and the video signal, which has been acquired from the reception unit, and input from the external output correspondence input terminal; and a control unit configured to acquire the timing signal supplied from the reception unit as a timing signal corresponding to a video signal of non-display in a state in which a displayed video is based on the video signal input from the external output non-correspondence input terminal, and the video signal of non-display input from the external output correspondence input terminal at that time is acquired by the reception unit in a case in which a process of a high-speed input switching function for switching between the video signal input from the external output non-correspondence input terminal and the video signal input from the external output correspondence input terminal is performed. 
     A method for controlling a display device according to one aspect of the present invention is a method for controlling a display device including: a reception unit configured to receive a video signal input from an external output correspondence input terminal and a timing signal corresponding to the video signal; and a video processing unit configured to perform processing on a video signal input from an external output non-correspondence input terminal and the video signal, which is acquired from the reception unit, input from the external output correspondence input terminal, the method including acquiring the timing signal supplied from the reception unit as a timing signal corresponding to a video signal of non-display in a state in which a displayed video is based on the video signal input from the external output non-correspondence input terminal, the video signal of non-display input from the external output correspondence input terminal at that time being acquired by the reception unit in a case in which a process of a high-speed input switching function for switching between the video signal input from the external output non-correspondence input terminal and the video signal input from the external output correspondence input terminal is performed. 
     Advantageous Effects of Invention 
     According to the present invention, when input switching is performed using a high-speed input switching function, the process is performed on a video signal passing through a reception unit by acquiring a timing of the reception unit, whereby a disturbance of a timing at the time of high-speed input switching can be prevented. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a block diagram illustrating an overview of a display device according to an embodiment of the present invention. 
         FIG. 2  is a block diagram used for describing a case in which a display device according to an embodiment of the present invention is independently used. 
         FIG. 3  is a block diagram used for describing a case in which a multiple-display system is built by connecting display devices according to an embodiment of the present invention. 
         FIG. 4  is a block diagram used for describing a case in which a multiple-display system is built by connecting display devices according to an embodiment of the present invention. 
         FIG. 5  is an explanatory diagram illustrating a case in which a high-speed input switching process is performed by a display device according to an embodiment of the present invention. 
         FIG. 6  is an explanatory diagram illustrating a case in which a high-speed input switching process is performed by a display device according to an embodiment of the present invention. 
         FIG. 7  is a flowchart illustrating a high-speed input switching process according to an embodiment of the present invention. 
         FIG. 8  is a flowchart illustrating another example of a high-speed input switching process according to an embodiment of the present invention. 
         FIG. 9  is a schematic block diagram illustrating a basic configuration of a display device according to the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, an embodiment of the present invention will be described with reference to the drawings.  FIG. 1  is a block diagram illustrating an overview of a display device  10  according to an embodiment of the present invention. As illustrated in  FIG. 1 , the display device  10  according to the embodiment of the present invention includes a video input terminal  11 , video input terminals  12   a  to  12   d , and a video output terminal  13 . In addition, the display device  10  includes a video processing unit  21 , a reception unit  22 , a display unit  23 , and a control unit  24 . 
     The video input terminal  11  is an external output non-correspondence video input terminal. As the video input terminal  11 , for example, an HDMI (registered trademark)  2 . 0  (high-definition multimedia interface 2.0) is used. A video signal input to the video input terminal  11  is transmitted to the video processing unit  21 . 
     The video input terminals  12   a  to  12   d  are external output non-correspondence video input terminals. As the video input terminals  12   a  to  12   d , for example, digital visual interface digital only (DVI-D) and HDMI 2.0 are used. Video signals input to the video input terminals  12   a  to  12   d  are transmitted to the reception unit  22 . 
     The video output terminal  13  is a video output terminal that outputs video signals to other devices. For example, HDMI 2.0 is used as the video output terminal  13 . 
     The video processing unit  21  performs various kinds of video processing on a display image such as resolution conversion, luminance adjustment, color adjustment, and the like. A video signal from the video input terminal  11  is input to the video processing unit  21 , and a video signal from the reception unit  22  is input to the video processing unit  21 . In addition, the video processing unit  21  includes a resolution setting unit  25 . By controlling writing and reading of an image memory, the resolution setting unit  25  sets a resolution of a display image. In addition, a two-screen display such as the PinP can be performed by this resolution setting unit  25 . Furthermore, image data of two screens is taken into the resolution setting unit  25 , one screen is displayed, the other screen is set to be not displayed, and switching between the displayed screen and the non-display screen is performed, whereby high-speed input switching can be performed. 
     The reception unit  22  receives video signals from a plurality of the video input terminals  12   a  to  12   d  and performs switching and output control of the video signals. A sink mode or a repeater mode can be set in the reception unit  22 . The sink mode is a mode in which the reception unit  22  is caused to operate as a signal receiver, and no video signal is output to the outside. At the time of the sink mode, the reception unit  22  outputs a video signal only to the video processing unit  21 , and a video signal is not output from the video output terminal  13 . The repeater mode is a mode in which the reception unit  22  is caused to operate as a relay device. In the repeater mode, the reception unit  22  outputs a video signal to the video processing unit  21  and outputs a video signal from the video output terminal  13 . 
     The display unit  23  displays an image based on a video signal processed by the video processing unit  21 . As the display unit  23 , for example, a liquid crystal display (LCD) is used. 
     The control unit  24  performs control of the reception unit  22  and the video processing unit  21 . In addition, the control unit  24  performs control of a high-speed input switching function. 
     The control unit  24  has a storage area in which various kinds of data can be stored therein. In addition, the storage area of the control unit  24  may be provided outside the control unit  24 . Such a storage area, for example, may be realized using, for example, a storage medium such as a hard disk drive (HDD), a flash memory, an electrically erasable programmable read only memory (EEPROM), a random access read/write memory (RAM), or a read only memory (ROM) or a storage device configured by an arbitrary combination of such storage media. As this storage device, for example, a nonvolatile memory may be used. 
       FIG. 2  is a block diagram used for describing a case in which the display device  10  according to the embodiment of the present invention is independently used. 
     In a case in which the display device  10  is independently used, the reception unit  22  is set to the sink mode. For this reason, a video signal is not output from the video output terminal  13 . Then, a video generating device  50  is connected to the external output non-correspondence video input terminal  11 . In accordance with this, a video signal from the video generating device  50  is transmitted to the video processing unit  21 , and an image based on the video signal from the video generating device  50  is displayed on the display unit  23 . 
       FIGS. 3 and 4  are block diagrams used for describing a case in which a multiple-display system is built by connecting display devices  10 - 1  to  10 - 4  according to the embodiment of the present invention. 
     As illustrated in  FIG. 3 , in a case in which the multiple-display system is built by connecting the display devices  10 - 1  to  10 - 4 , the video generating device  50  and the external output correspondence video input terminal  12   a  of the foremost display device  10 - 1  are connected. Then, from the next stage, in the display device  10 - n  (here, n is an integer), the video input terminal  12   a  thereof is connected to the video output terminal  13  of the display device  10 -( n −1) of the previous stage, and the video output terminal  13  thereof is connected to the external output correspondence video input terminal  12   a  of the display device  10 -( n +1) of the next stage. In other words, the video output terminal  13  of the display device  10 - 1  and the video input terminal  12   a  of the display device  10 - 2  of the next stage are connected. The video output terminal  13  of the display device  10 - 2  and the video input terminal  12   a  of the display device  10 - 3  of the next stage are connected. The video output terminal  13  of the display device  10 - 3  and the video input terminal  12   a  of the display device  10 - 4  of the next stage are connected. Here, although the video input terminal  12   a  is used as an external output correspondence video input terminal, any one of the video input terminals  12   b  to  12   d  that are correspondence with other external outputs may be used. 
     As illustrated in  FIG. 4 , in a case in which a multiple-display is configured using display devices according to the embodiment of the present invention, the video input terminal  12   a  of the display device  10 - n  is connected to the video output terminal  13  of the display device  10 -( n −1) of the previous stage. In addition, the video output terminal  13  of the display device  10 - n  is connected to the video input terminal  12   a  of the display device  10 -( n +1) of the next stage. In addition, at this time, the reception unit  22  is set to the repeater mode. 
     A video signal is transmitted to the video input terminal  12   a  from the video output terminal  13  of the display device  10 -( n −1) of the previous stage. This video signal is input to the reception unit  22  of the display device  10 - n . The reception unit  22  is set to the repeater mode, and thus, a video signal from the reception unit  22  is transmitted to the video processing unit  21  and is output from the video output terminal  13 . In accordance with this, an image based on the video signal from the display device  10 -( n −1) is displayed in the display unit  23  of the display device  10 - n . In addition, a video signal from the reception unit  22  is output from the video output terminal  13  and is transmitted to the video input terminal  12   a  of the display device  10 -( n +1) of the next stage. 
     In this way, the display device  10  according to the embodiment of the present invention has a function of outputting a video signal from the video output terminal  13 . In this way, the display device  10  can be independently used or may be used by building a multiple-display system. 
     Next, the process of a high-speed input switching function according to the embodiment of the present invention will be described.  FIGS. 5 and 6  are explanatory diagrams illustrating cases in which a high-speed input switching process is performed by the display device according to the embodiment of the present invention. 
     As described above, the display device  10  according to the embodiment of the present invention can receive a video signal from the external output non-correspondence video input terminal  11  as an input and display a screen on the display unit  23 . In addition, the display device  10  according to the embodiment of the present invention can build a multiple-display by receiving a video signal from a display device of the previous stage to the external output correspondence video input terminals  12   a  to  12   d  as an input and outputting a video signal to a display device of the next stage from the video output terminal  13 . 
     In the case illustrated in  FIG. 5 , by connecting the video generating device  50  to the external output non-correspondence video input terminal  11 , a video signal from the video generating device  50  can be displayed on the display unit  23 . In addition, by connecting a display device  10 -( n −1) of the previous stage to the external output correspondence video input terminal  12   a  and connecting a display device  10 -( n −1) of the next stage to the video output terminal  13 , multiple-display can be built. Here, switching between a video signal from the external output non-correspondence video input terminal  11  and a video signal from the external output correspondence video input terminal  12   a  is performed using the high-speed input switching function. 
     The high-speed input switching function is realized by taking in image data of two screens (a video signal from the external output non-correspondence video input terminal  11  and a video signal from the external output correspondence video input terminal  12   a ) of two screens, that is, one video signal and the other video signal correspondence with image data of two screens in the resolution setting unit  25 , displaying a screen of one video signal, setting a screen of the other video signal to be a non-display, and switching between the displayed screen and the non-display screen. For this reason, generally, the control unit  24  performs a process using a timing signal T 1  from the resolution setting unit  25  that is synchronized with a timing of an input video signal. In other words, the timing signal T 1  is input to the resolution setting unit  25  together with a video signal. The resolution setting unit  25  outputs the timing signal T 1  to the control unit  24 . Alternatively, the timing signal T 1  is input to the resolution setting unit  25  as a signal included in a video signal. By extracting the timing signal T 1  from the video signal, the resolution setting unit  25  generates the timing signal T 1 . The resolution setting unit  25  outputs the extracted timing signal T 1  to the control unit  24 . Here, the timing signal T 1  is a synchronization signal for drawing a video signal (a video signal from the external output non-correspondence video input terminal  11 ), is composed of a vertical synchronization signal and a horizontal synchronization signal, and is a signal from which a resolution, a vertical-direction frequency, a horizontal-direction frequency, and a display type of the video signal can be acquired. The display type is signal information included in a synchronization signal representing a display method indicating whether a video signal is a signal for display using RGB (three colors) or a signal for display using color difference signals (Y/PB/PR). 
     However, in a case in which a video signal is input from the external output non-correspondence video input terminal  11  and is displayed on the display unit  23 , the sink mode is set to the reception unit  22 . In a case in which a multiple-display is built, the repeater mode is set to the reception unit  22 . Thus, when the input is switched between a video signal of the external output non-correspondence video input terminal  11  and a video signal of the external output correspondence video input terminal  12   a , mode switching between the sink mode and the repeater mode occurs in the reception unit  22 . At this time, the reception unit  22  temporarily stops output of a signal at the time of mode switching. For this reason, the timing signal T 1  from the resolution setting unit  25  is disturbed, and the control unit  24  detects an unstable signal state. 
     Thus, in this embodiment, as illustrated in  FIG. 6 , in the case of being switched to a video signal passing through the reception unit  22 , the control unit  24  is configured to acquire a timing signal T 2  from the reception unit  22 . In other words, the timing signal T 2  is input to the reception unit  22  together with a video signal. The reception unit  22  outputs the timing signal T 2  to the control unit  24 . Alternatively, the timing signal T 2  is input to the reception unit  22  as a signal included in a video signal. By extracting the timing signal T 2  from the video signal, the reception unit  22  generates the timing signal T 2 . The reception unit  22  outputs the extracted timing signal T 2  to the control unit  24 . Here, the timing signal T 2  is a synchronization signal for drawing a video signal (a video signal from the external output correspondence video input terminal  12   a ), is composed of a vertical synchronization signal and a horizontal synchronization signal, and is a signal from which a resolution, a vertical-direction frequency, a horizontal-direction frequency, and a display type of a video signal can be acquired. The timing signal T 2  from the reception unit  22  is a timing signal output from a signal source and thus is stable regardless of a change in the mode of the reception unit  22 . For this reason, when the high-speed input switching function is controlled using the timing signal T 2 , a stable process can be performed even when the mode of the reception unit  22  is switched. 
       FIG. 7  is a flowchart illustrating the high-speed input switching process according to the embodiment of the present invention. 
     The flowchart illustrated in  FIG. 7  may be executed with an arbitrary period timing (for example, once per second). Alternatively, since a timing signal is acquired for drawing a video signal (for example, once per 50 milliseconds), the flowchart illustrated in  FIG. 7  may be executed together with a flow for acquiring a timing signal. 
     The flowchart illustrated in  FIG. 7  is executed once per second on the background. 
     On the other hand, a user is not aware of switching of an input change super function (the high-speed input switching function) between validity/invalidity at a certain timing. At the same time, a user can freely set signals that are a front signal (“a displayed video” in the following flow) and a back signal (“a video to be switched to in the following flow). For example, a user can freely select the signals on an on-screen display (OSD) screen of a monitor (the display device). 
     During this time, the flowchart illustrated in  FIG. 7  is executed once per second. In addition, for performing high-speed switching in a state in which the input change super function is validated, a button for high-speed switching corresponding to the input change super function is prepared in a remote controller. A user selects a terminal corresponding to the front signal or the back signal by selecting the front signal or the back signal set on the OSD screen and pressing a button. In other words, a user may select the front signal or may select the back signal. 
     In this way, a target for the input change super function is the front signal or the back signal, and the front signal or the back signal is set on a separate OSD screen. 
     In addition, switching of display is performed last in a situation in which all the conditions for selecting the timing signal T 1  or T 2  are satisfied in the flowchart illustrated in  FIG. 7 . Thus, a relationship and an order are formed such that, after execution of the flowchart illustrated in  FIG. 7 , the front signal can be switched to the back signal at a high speed. 
     (Step S 1 ) The control unit  24  determines whether or not the high-speed input switching function is validated. In a case in which the high-speed input switching function is not validated (Step S 1 : No), the control unit  24  causes the process to proceed to Step S 2 . On the other hand, in a case in which the high-speed input switching function is validated (Step S 1 : Yes), the control unit  24  causes the process to proceed to Step S 3 . 
     (Step S 2 ) The control unit  24  acquires a timing signal T 1  from the resolution setting unit  25  side and ends the process. 
     (Step S 3 ) The control unit  24  determines whether or not a video displayed on the display unit  23  is a video of the external output non-correspondence input terminal. In a case in which the video displayed on the display unit  23  is a video of the external output non-correspondence input terminal (Step S 3 : Yes), the control unit  24  causes the process to proceed to Step S 4 . In a case in which the video displayed on the display unit  23  is a video of the external output correspondence input terminal (Step S 3 : No), the control unit  24  causes the process to proceed to Step S 5 . 
     (Step S 4 ) In a case in which it is determined that the video displayed on the display unit  23  is a video of the external output non-correspondence input terminal in Step S 3  (Step S 3 : Yes), the video signal has not passed through the reception unit  22 , and thus the control unit  24  acquires a timing signal T 1  from the resolution setting unit  25  side and causes the process to proceed to Step S 6 . 
     (Step S 5 ) In a case in which it is determined that the video displayed on the display unit  23  is not a video of the external output non-correspondence input terminal in Step S 3  (Step S 3 : No), the displayed video is a video signal passing through the reception unit  22 , and thus the control unit  24  acquires a timing signal T 2  from the reception unit  22  side and causes the process to proceed to Step S 6 . 
     (Step S 6 ) The control unit  24  determines whether or not a video for which input switching is performed is a video of the external output correspondence input terminal. In a case in which the video for which input switching is performed is a video of the external output correspondence input terminal (Step S 6 : Yes), the control unit  24  causes the process to proceed to Step S 7 . In a case in which the video for which input switching is performed is not a video of the external output correspondence input terminal (Step S 6 : No), the control unit  24  causes the process to proceed to Step S 8 . 
     (Step S 7 ) In a case in which it is determined that the video for which input switching is performed is a video of the external output correspondence input terminal in Step S 6  (Step S 6 : Yes), the video signal has passed through the reception unit  22 , and thus the control unit  24  acquires a timing signal T 2  from the reception unit  22  side. 
     (Step S 8 ) In a case in which it is determined that the video for which input switching is performed is not a video of the external output correspondence input terminal in Step S 6  (Step S 6 : No), the video signal has not passed through the reception unit  22 , and thus the control unit  24  acquires a timing signal T 1  from the resolution setting unit  25  side. 
     In this way, in this embodiment, in a case in which the video signal at the time of performing input video switching is a video signal passing through the reception unit  22 , the control unit  24  acquires the timing signal T 2  from the reception unit  22  side and performs the process. In accordance with this, when switching between a video signal from the external output non-correspondence video input terminal and a video signal from the external output correspondence video input terminal is performed, a deviation in the timing does not occur. 
     In other words, switching between a video signal from the external output non-correspondence video input terminal  11  and a video signal from the external output correspondence video input terminal  12   a  can be performed using the high-speed input switching function. In this case, the processes of Steps S 1 , S 3 , S 4 , S 6 , and S 7  are performed, and the control unit  24  acquires a timing signal T 2  from the reception unit  22  side in accordance with determination results acquired in Steps S 3  and S 6  and performs high-speed input switching. 
     In other words, in a state in which the displayed video is a video signal input from the external output non-correspondence video input terminal  11  (the result of Step S 3 ), and a video signal of non-display input from the external output correspondence video input terminal  12   a  has been acquired by the reception unit  22  (the result of Step S 6 ) at that time, the control unit  24  acquires a timing signal T 2  supplied from the reception unit  22  as a timing signal corresponding to the video signal of non-display (Step S 7 ). 
     Then, the control unit  24  causes the video signal of non-display input from the external output correspondence video input terminal  12   a  to be drawn, in other words, sets a video signal of non-display to a video signal of display (a video signal to be displayed) by controlling the video processing unit  21  on the basis of the acquired timing signal T 2 . 
     In accordance with this, when switching between a video signal from the external output non-correspondence video input terminal and a video signal from the external output correspondence video input terminal is performed, an unstable signal state in which a deviation in the timing occurs can be avoided, and input switching can be performed at a high speed. 
     In addition, since information of a resolution and a frequency is necessary for adjustment of a viewing angle of an output signal at the time of displaying the output signal on a panel (the display unit  23 ), the video processing unit  21  that performs screen display at the current time point acquires a timing signal T 1  from a scaler (the resolution setting unit  25 ) in Step S 4 . 
     Furthermore, switching between a video signal from the external output correspondence video input terminal  12   a  and a video signal from the external output non-correspondence video input terminal  11  can be performed using the high-speed input switching function. In this case, the processes of Steps S 1 , S 3 , S 5 , S 6 , and S 8  are performed, and the control unit  24  acquires a timing signal T 1  from the resolution setting unit  25  in accordance with determination results acquired in Steps S 3  and S 6  and performs high-speed input switching. 
     In other words, in a state in which the displayed video is a video signal input from the external output correspondence video input terminal  12   a  (the result of Step S 3 ), and a video signal of non-display input from the external output non-correspondence video input terminal  11  has been acquired by the resolution setting unit  25  (the result of Step S 6 ) at that time, the control unit  24  acquires a timing signal T 1  supplied from the resolution setting unit  25  as a timing signal corresponding to the video signal of non-display (Step S 8 ). 
     Then, the control unit  24  causes the video signal of non-display input from the external output non-correspondence video input terminal  11  to be drawn, in other words, sets a video signal of non-display to a video signal of display (a video signal to be displayed) by controlling the video processing unit  21  on the basis of the acquired timing signal T 1 . 
     In this case, when switching between a video signal from the external output non-correspondence video input terminal and a video signal from the external output correspondence video input terminal is performed, an unstable signal state in which a deviation in the timing occurs can be avoided, and input switching can be performed at a high speed, and the flowchart illustrated in  FIG. 7  is a flowchart for operating a product. 
     In other words, the flowchart illustrated in  FIG. 7  is a flowchart in which determination can be performed in one flowchart even when any one of a video signal input from the external output correspondence video input terminal  12   a  and a video signal input from external output non-correspondence video input terminal  11  is displayed as a front signal, and a timing signal that is necessary for a back signal can be acquired. 
       FIG. 8  is a flowchart illustrating another example of a high-speed input switching process according to the embodiment of the present invention. 
       FIG. 8  is a flowchart that mainly represents the process performed by the control unit  24  in a case in which a displayed video is a video signal input from the external output non-correspondence video input terminal  11 , and a video to be switched to is a video signal input from the external output correspondence video input terminal  12   a.    
     (Step S 11 ) It is determined whether or not the input change super function is validated. 
     More specifically, the control unit  24  determines whether or not the high-speed input switching function is validated. 
     In a case in which the high-speed input switching function is not validated (Step S 11 : No), the control unit  24  repeatedly performs the process of Step S 11 . In a case in which the high-speed input switching function is validated (Step S 11 : Yes), the control unit  24  causes the process to proceed to Step S 12 . 
     (Step S 12 ) It is determined whether or not a displayed video signal is a signal input to the scaler. 
     More specifically, the control unit  24  determines whether or not the displayed video is a video signal input from the external output non-correspondence video input terminal  11  and is a signal input to the resolution setting unit  25 . 
     In a case in which the displayed video is a video signal input from the external output correspondence video input terminal  12   a  and is a signal input to the reception unit  22  (Step S 12 : No), the control unit  24  causes the process to proceed to Step S 11 . On the other hand, in a case in which the displayed video is a video signal input from the external output non-correspondence video input terminal  11  and is a signal input to the resolution setting unit  25  (Step S 12 : Yes), the control unit  24  causes the process to proceed to Step S 13 . 
     (Step S 13 ) It is determined whether or not a video signal of non-display is a signal input to a digital receiver RX block. 
     More specifically, the control unit  24  determines whether or not a video to be switched to is a video signal input from the external output correspondence video input terminal  12   a  and is a signal input to the reception unit  22 . 
     In a case in which a video to be switched to is a video signal input from the external output non-correspondence video input terminal  11  and is a signal input to the resolution setting unit  25  (Step S 13 : No), the control unit  24  causes the process to proceed to Step S 11 . On the other hand, in a case in which the displayed video is a video signal input from the external output correspondence video input terminal  12   a  and is a signal input to the reception unit  22  (Step S 13 : Yes), the control unit  24  causes the process to proceed to Step S 14 . 
     (Step S 14 ) A timing signal is acquired from the digital receiver RX block. 
     More specifically, the control unit  24  acquires the timing signal T 2  supplied from the reception unit  22  as a timing signal corresponding to the video signal input from the external output non-correspondence video input terminal  11 . 
     In this way, in this embodiment, in a case in which a video signal at the time of performing input video switching is a video signal passing through the reception unit  22 , the control unit  24  acquires the timing signal T 2  from the reception unit  22  side and performs the process. In accordance with this, when switching between a video signal from the external output non-correspondence video input terminal and a video signal from the external output correspondence video input terminal is performed, a deviation in the timing does not occur. 
     In other words, switching between a video signal from the external output non-correspondence video input terminal  11  and a video signal from the external output correspondence video input terminal  12   a  can be performed using the high-speed input switching function. In this case, the processes of Steps S 11 , S 12 , S 13 , and S 14  are performed, and the control unit  24  acquires the timing signal T 2  of the reception unit  22  side in accordance with determination results acquired in Steps S 12  and S 13  and performs high-speed input switching. 
     In other words, in a state in which the displayed video is a video signal input from the external output non-correspondence video input terminal  11  (the result of Step S 12 ), and a video signal of non-display input from the external output correspondence video input terminal  12   a  has been acquired by the reception unit  22  (the result of Step S 13 ) at that time, the timing signal T 2  supplied from the reception unit  22  is acquired as a timing signal corresponding to the video signal of non-display (Step S 14 ). 
     Then, the control unit  24  causes the video signal of non-display input from the external output correspondence video input terminal  12   a  to be drawn, in other words, sets a video signal of non-display to a video signal of display (a video signal to be displayed) by controlling the video processing unit  21  on the basis of the acquired timing signal T 2 . 
     In accordance with this, when switching between a video signal from the external output non-correspondence video input terminal and a video signal from the external output correspondence video input terminal is performed, an unstable signal state in which a deviation in the timing occurs can be avoided, and input switching can be performed at a high speed. 
     Next, an operation of the control unit  24  causing the video processing unit  21  to display a video signal input from the external output correspondence video input terminal  12   a  (hereinafter referred to as a video signal A) using a timing signal T 3  generated by the video processing unit  21  will be described. 
     Here, the timing signal T 3  is input to the video processing unit  21  together with a video signal. The video processing unit  21  outputs the timing signal T 3  to the control unit  24 . Alternatively, the timing signal T 3  is input to the video processing unit  21  as a signal included in a video signal. The video processing unit  21  generates a timing signal T 3  by extracting the timing signal T 3  from the video signal. The video processing unit  21  outputs the extracted timing signal T 3  to the control unit  24 . Here, the timing signal T 3  is a synchronization signal for drawing a video signal (hereinafter referred to as a video signal A), is composed of a vertical synchronization signal and a horizontal synchronization signal, and is a signal from which a resolution, a vertical-direction frequency, a horizontal-direction frequency, and a display type of the video signal can be acquired. 
     As described above, the control unit  24  displays a video signal input from the external output non-correspondence input terminal  11  on the display unit  23  using the video processing unit  21 . When a switching instruction for switching a video signal that is a target to be displayed to a video signal A input from the external output correspondence input terminal  12   a  is accepted, the control unit  24  causes the video processing unit  21  to perform the process of displaying the video signal A on the display unit  23  using the timing signal T 2  supplied from the reception unit  22  (a timing signal corresponding to the video signal A). The video processing unit  21  displays the video signal A on the display unit  23  using the timing signal T 2  supplied from the control unit  24  on the basis of an instruction from the control unit  24 . 
     Then, the video processing unit  21  performs signal processing on the video signal A and displaying, and, immediately after switching to the video signal A, although the timing signal T 3  cannot be generated or the generated timing signal T 3  is a signal that is in an unstable state, when a time of certain degrees elapses after switching, a stable timing signal T 3  can be generated on the basis of this video signal A. In other words, the control unit  24  causes the video processing unit  21  to perform the process of displaying the video signal A on the display unit  23  using the timing signal T 2  supplied from the reception unit  22  (a timing signal corresponding to the video signal A) and, when the timing signal T 3  is generated by the video processing unit  21 , causes the video processing unit  21  to perform the process of displaying the video signal A on the display unit  23  using the timing signal T 3  generated by this video processing unit  21  instead of using the timing signal T 2  supplied from the reception unit  22 . At this time, the control unit  24  instructs the reception unit  22  to stop supply of the timing signal T 2 . The reception unit  22  stops supply of the timing signal T 2  to the control unit  24  on the basis of a stop instruction from the control unit  24 . 
     In accordance with this, when a state in which the timing signal T 3  can be generated by the video processing unit  21  is formed, the supply of the timing signal T 2  from the reception unit  22  to the control unit  24  stops, and thus, the reception unit  22  can be caused not to perform an unnecessary process, and in accordance with this, the load of the display device  10  can be reduced. 
       FIG. 9  is a schematic block diagram illustrating a basic configuration of a display device according to the present invention. The display device  100  according to the present invention includes a reception unit  106  that receives a video signal input from the external output correspondence input terminal  102  and a timing signal T 2  corresponding to the video signal, a video processing unit  105  that performs processing on a video signal input from an external output non-correspondence input terminal  101  and a video signal, which is acquired from the reception unit  106 , input from the external output correspondence input terminal  102 , and a control unit  107 . 
     In a case in which the process of the high-speed input switching function is performed for switching between a video signal input from the external output non-correspondence input terminal  101  and a video signal input from the external output correspondence input terminal  102 , in a state in which a displayed video is based on the video signal input from the external output non-correspondence input terminal  101 , and a video signal of non-display input from the external output correspondence input terminal  102  at that time is acquired by the reception unit  106 , the control unit  107  acquires a timing signal T 2  supplied from the reception unit  106  as a timing signal corresponding to the video signal of non-display. 
     All or a part of the display device  10  according to the embodiment described above may be realized using a computer. In such a case, a program used for realizing this function may be recorded on a computer-readable recording medium, and the display device may be realized by causing a computer system to read the program recorded on this recording medium and execute the program. A “computer system” described here includes an OS and hardware such as peripherals. In addition, the “computer-readable recording medium” represents a portable medium such as a flexible disc, a magneto-optical disk, a ROM, or a CD-ROM or a storage device such as a hard disk built into a computer system. Furthermore, the “computer-readable recording medium” may include a medium dynamically storing the program for a short time such as a communication line of a case in which the program is transmitted through a network such as the Internet or a communication circuit line such as a telephone line and a medium storing the program for a predetermined time such as an internal volatile memory of the computer system that becomes a server or a client in such a case. In addition, the program described above may be a program used for realizing a part of the function described above or a program that can realize the function described above in combination with a program that is already recorded in the computer system and may be realized using a programmable logic device such as an FPGA. 
     As above, although the embodiment of the present invention has been described in detail with reference to the drawings, a specific configuration is not limited to this embodiment, and designs and the like in a range not departing from the concept of the present invention are included therein. 
     REFERENCE SIGNS LIST 
     
         
         
           
               10 ,  100  Display device 
               11 ,  101  External output non-correspondence video input terminal 
               12   a  to  12   d ,  102  External output correspondence video input terminal 
               13 ,  103  Video output terminal 
               21 ,  105  Video processing unit 
               22 ,  106  Reception unit 
               23  Display unit 
               24 ,  107  Control unit