Abstract:
A display system includes an electronic device, a display device, a power line and two converters. The electronic device is used to provide image data, and the display device displays images according to the image data. The first converter is coupled to the electronic device and plugged to a first power socket for receiving the image data sent by the electronic device and power from the power line, combining image signal and power signal and transmitting the combined signal to a second converter via the power line. The second converter is coupled to the display device and plugged to a second power socket for receiving the power from the power line and the image data sent by the first converter and separating the signal to transmit the image data to the display device.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates to a display system and, more particularly, to a display system which transmits image data via a power line. 
         [0003]    2. Description of the Related Art 
         [0004]    With the development of information technology and multi-media technology, users usually store mass image data via various electronic devices in daily life, and then process image data via a display device. For example, when in a meeting or a presentation, the speaker may use a projector to project the image data stored in a notebook computer on a screen to facilitate the discussion. 
         [0005]    Generally, the electronic device outputs the image data via a specific interface, and then transmits the image data to the display device via a cable. The display device may directly display the image (such as using a liquid crystal display (LCD) screen) or project the image (such as using the projector). An analog display system uses analog signal interfaces such as a D-subminiature (D-sub) interface or a composite video broadcast signal (CVBS) interface, and a digital display system uses digital signal interfaces such as a high definition multimedia interface (HDMI) or a digital visual interface (DVI). In the conventional display system, the power cable and the signal cable are independent of each other. The electronic device and the display device are connected to the power cable and the signal cable with different connecting ports according to different video interface specifications. In another aspect, the power for the display equipment is usually directly provided via the power line. 
         [0006]      FIG. 1  is a schematic diagram showing a conventional display system  100 . The display system  100  includes an electronic device  10  (such as a personal computer), a display device  20  (such as a projector) and cables C AC1  and C AC2 . The specification of C AC1  varies along with the specification of the image output terminal of the electronic device  10 . For example, when the connector of the image output terminal of the electronic device  10  is a video graphics array (VGA) connector, the cable C AC1  is also the VGA cable. The electronic device  10  includes a power input terminal P 1  which may be coupled to the power socket  41  via the cable C AC2  to receive the power and an image output terminal Q 1  which may output the image data via the cable C AC1 . The display device  10  includes a power input terminal P 2  and an image input terminal Q 2 , which may be coupled to the power socket  42  to receive the power via the cable C AC1 . 
         [0007]    In different practical applications, the architecture of devices in the display system  100  may be different. An extension cable C AC1  is usually needed to transmit the images between the electronic device  10  and the display device  20 . As a result, not only the cable is not easily laid, but also the display quality is affected due to the signal attenuation. In addition, some kinds of electronic devices  10  may not be detected correctly. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    The invention discloses a display system including an electronic device, a first converter, a second converter and a display device. The electronic device is used to output an image data. The first converter is plugged to a first socket and coupled to the electronic device for receiving image data sent by the electronic device and adding the image data to the power line to transmit the image data via the power line. The second converter is plugged to the second socket for receiving the power and image data transmitted from the power line, separating the power and the image data and outputting the image data. The display device is coupled to the second converter for receiving the image data outputted by the second converter and displaying the image data. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a block diagram showing a conventional display system; 
           [0010]      FIG. 2  is a block diagram showing the display system in a first embodiment of the invention; 
           [0011]      FIG. 3  is a block diagram showing the display system in a second embodiment of the invention; and 
           [0012]      FIG. 4  and  FIG. 5  are schematic diagrams showing the converter in embodiments of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0013]      FIG. 2  is a block diagram showing a display system  200  in the first embodiment of the invention. The display system  200  includes an electronic device  10  (such as a personal computer), a display device  20  (such as a projector), a power line  30 , two converters  31  and  32 , two power sockets  41  and  42  and cables C AC1 , C AC2 , C D1  and C D2 . In a common family, the electronic device  10  and the display device  20  may be disposed in two rooms RM 1  and RM 2 , respectively. The two rooms have the power sockets  41  and  42 , respectively, to receive the power signal of the power line  30 . The converter  31  may be a three-terminal element (denoted by A 1  to A 3  in  FIG. 2 ), and the converter  32  also may be a three-terminal element (denoted by B 1  to B 3  in  FIG. 2 ). The function and structure of the converters  31  and  32  are detailed illustrated hereinafter. The electronic device  10  includes an image output terminal Q 1  (such as a VGA port or a DVI port of the personal computer) and a power input terminal P 1 . The power input terminal P 1  is coupled to the A 3  terminal of the converter  31  via the cable C AC1  to receive the power from the power line  30 . The image output terminal Q 1  is coupled to the A 2  terminal of the converter  31  via the cable C D1  to transmit the image data. The display device  20  includes a power input terminal P 2  and an image input terminal Q 2 . The power input terminal P 2  is coupled to the B 3  terminal of the converter  32  via the cable C AC2  to receive the power of the power line  30 , and the image input terminal Q 2  is coupled to the B 2  terminal of the converter  32  via the cable C D2  to receive the image data provided by the electronic device  10 . The converter  31  is plugged in the socket  41  via the A 1  terminal, and the converter  32  is plugged in the socket  42  via the B 1  terminal. The sockets  41  and  42  are connected to each other via the power line  30 . 
         [0014]    In the first embodiment of the invention, the converter  31  is a multiplexer, and the converter  32  is a demultiplexer. Therefore, in the display system  200  of the invention, the converter  31  receives the image data sent by the electronic device  10 , adds the image data to the power signal, and then transmits the power and the image data via the power line  30 . In another aspect, the converter  32  receives the power signal and the image data transmitted from the power line  30  and separates the power signal and the image data. Therefore, the power signal and the image data can be transmitted to the power input terminal P 2  and the image input terminal Q 2  of the display device  20 , respectively. The invention is not limited to the embodiment in  FIG. 2 . 
         [0015]      FIG. 3  is a block diagram showing the function of the display system  300  in the second embodiment of the invention. The display system  300  includes an electronic device  10  (such as a personal computer), a display device  20  (such as a projector), a power line  30 , two converters  33  and  34 , four power sockets  41 ,  42 ,  43  and  44  and cables C AC1 , C AC2 , C D1  and C D2 . In a common family, the electronic device  10  and the display device  20  may be disposed in two rooms RM 1  and RM 2 , respectively. The room RM 1  has the power sockets  41  and  43  to receive the power signal from the power line  30 . The room RM 2  has the power sockets  42  and  44  to receive the power signal from the power line  30 . The converter  33  may be a two-terminal element (denoted by A 1  and A 2  in  FIG. 3 ), and the converter  34  also may be a two-terminal element (denoted by B 1  and B 2  in  FIG. 3 ). The function and structure of the converters  33  and  34  are illustrated hereinafter. The electronic device  10  includes an image output terminal Q 1  (such as the VGA port or the DVI port of the personal computer) and a power input terminal P 1 . The power input terminal P 1  is coupled to the socket  43  via the cable C AC1  to receive the power from the power line  30 . The image output terminal Q 1  is coupled to the A 2  terminal of the converter  33  via the cable C D1  to transmit the image data. The display device  20  includes a power input terminal P 2  and an image input terminal Q 2 . The power input terminal P 2  is coupled to the socket  44  via the cable C AC2  to receive the power from the power line  30 , and the image input terminal Q 2  is coupled to the B 2  terminal of the converter  34  via the cable C D2  to receive the image data provided by the electronic device  10 . The converter  33  is plugged in the socket  41  via the A 1  terminal, the converter  34  is plugged in the socket  42  via the B 1  terminal, and the sockets  41  and  42  are connected to each other via the power line  30 . 
         [0016]    In the second embodiment of the invention, the converter  33  is a multiplexer and the converter  34  is a demultiplexer. Therefore, in the display system  300  of the invention, the converter  33  receives the image data sent by the electronic device  10 , adds the image data to the power signal, and then transmits the power and the image data via the power line  30 . In another aspect, the converter  34  receives and separates the power signal and the image data. Therefore, the converter can transmit the image data to the image input terminal Q 2  of the display device  20 . The invention is not limited to the embodiment in  FIG. 3 . 
         [0017]      FIG. 4  is a schematic diagram showing the converter  31  in the first embodiment of the invention. In the embodiment, the display device  20  and the electronic device  10  send and receive multi-media information via an analog video interface, and thus the A 2  terminal of the converters  31  may be set as a VGA terminal with 15 pins. According to the power supply specification of the power line  30 , the A 3  terminal of the converter  31  may be designed to be a B-type socket with three slots, and thus it allows the cable C AC1  to be plugged in. The A 1  terminal of the converter  32  may be designed to be the B-type plug with three pins, and thus it may be plugged into the socket  41 . According to the signal display specifications of the electronic device  10  and the display device  20  and the power supply systems in different districts, the Al to A 3  terminals of converter  31  may be different. The invention is not limited to the embodiment in  FIG. 4 . 
         [0018]      FIG. 5  is a schematic diagram showing the converter  32  in the first embodiment of the invention. In the embodiment, the electronic device  10  and the display device  20  send and receive multi-media information via the analog video interface, and the B 2  terminal of the converter  32  may be designed as a D-sub terminal with 15 pins. The B 1  terminal and B 3  terminal of the converter  32  may be correspondingly designed according to the power supply specification of the power line  30 . For example, the B 3  terminal of the converter  32  may be designed to be a B-type socket with three slots, and thus it allows the cable C AC2  to be plugged in. The B 1  terminal of the converter  31  may be designed to be the B-type plug with three pins, and it may be plugged into the socket  42 . According to the signal display specifications of the display device  20  and the electronic device  10  and the power supply system in different districts, the B 1  to B 3  terminals of converter  32  can be different. The invention is not limited to the embodiment in  FIG. 5 . 
         [0019]    In another aspect, the structure of the converter  33  in the second embodiment is similar to that of the converter  31  in the first embodiment of the invention, and the structure of the converter  34  in the second embodiment is similar to that of the converter  32  in the first embodiment of the invention. Therefore, they are not illustrated herein again for concise purpose. 
         [0020]    In the invention, the display system uses a power line to transmit power and image data, and then transmits the image data to the display device after the converter separates the power and the image data. Therefore, an extension cable is not needed in transmitting image signals. In the invention, the display system is easy to be laid, and the signal quality would not be reduced due to the signal attenuation. 
         [0021]    Although the present invention has been described in considerable detail with reference to certain preferred embodiments thereof, the disclosure is not for limiting the scope of the invention. Persons having ordinary skill in the art may make various modifications and changes without departing from the scope. Therefore, the scope of the appended claims should not be limited to the description of the preferred embodiments described above.