Abstract:
A display method, in which in a plurality of universal serial bus (USB) systems shares one display device, and USB devices connected to the display device and USB devices connected to the plurality of USB systems are shared,. The method includes, while output of a first predetermined USB system, among the plurality of USB systems, is transmitted to the display device, providing a predetermined menu to select a USB device to be shared and selecting a second predetermined USB system to connect to the selected USB device; if a menu item is selected, disabling a driver, which corresponds to the shared USB device in the first USB system; buffering information transmitted from the shared USB device in the display device; and transmitting the information, which is buffered in the display device, to the driver, which corresponds to the shared USB device, in the second USB system.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims the priority of Korean Patent Application No. 2002-41991, filed on Jul. 18, 2002, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a display apparatus and method, and more particularly, to a display apparatus and method, by which screen switching and switching of an input device thereof are automatically performed, and a universal serial bus (USB) device connected to a monitor hub and a USB device connected to a PC are shared between several PCs when several PCs are connected to one monitor. 
   2. Description of the Related Art 
     FIGS. 1A and 1B  are block diagrams illustrating the structure of a conventional display apparatus. Hereinafter, a PC mainframe is referred to as a PC.  FIG. 1A  illustrates the conventional setup of a monitor shared between two PCs. A user selects a corresponding PC (first PC  100   a  or second PC  103   a ) input from an input changeover switch  106 - 1   a . A MICOM (not shown) of the monitor  106   a  senses the PC input and outputs a control signal which enables an RGB signal to be output from the corresponding PC (first PC  100   a  or second PC  103   a ) and to be input to the monitor  106   a . The following operation is similar to the normal operation of a monitor. If the user switches the input changeover switch  106   a - 1   a  to the first PC  100   a , the monitor  106   a  receives and displays the RGB signal output from the first PC  100   a . A first keyboard  101   a  or first mouse  102   a  is used as an input device to the first PC  100   a . If the user switches the input changeover switch  106 - 1   a  to a second PC  103   a , the monitor  106  receives and displays the RGB signal output from the second PC  103   a . A second keyboard  104   a  or second mouse  105   a  is used as an input device to the second PC  103   a.    
   As many input devices as PCs are required in the structure of the conventional display apparatus shown in  FIG. 1A . This requirement demands a large space to accommodate the two or more input devices. In addition, the user can be easily confused when trying to select the input device that corresponds to the output screen. 
   In  FIG. 1B , a USB hub  103 - 2   b  is included in the display apparatus. If the user selects a PC (first PC  100   b  or second PC  101   b ) using an input changeover switch  103 - 1   b , a RGB signal is input to a monitor  103   b  from the selected PC and displayed on the screen. Simultaneously, an upstream port of the USB hub  103 - 2   b  is physically connected to the selected PC, providing support to input devices (keyboard  104   b  and mouse  105   b ). 
   In  FIG. 1B , unlike in  FIG. 1A , since input devices (keyboard  104   b  and mouse  105   b ) are connected to a USB port of the monitor  103   b , as many input devices as PCs are not required. However, the user must directly select the desired PC using the input changeover switch  103 - 1   b . In this case, the upstream port of the USB hub  103 - 2   b  is physically disconnected from or connected to the corresponding PC. However, it is difficult to connect other peripheral devices, other than the keyboard  104   b  or mouse  105   b , to the corresponding PC. 
   SUMMARY OF THE INVENTION 
   The present invention provides a display apparatus and method, by which screen switching and switching of an input device thereof are automatically performed, and a universal serial bus (USB) device connected to a monitor hub and a USB device connected to a PC are shared between several PCs when several PCs are connected to one monitor. 
   According to an aspect of the present invention, there is included a display method, in which a plurality of universal serial bus (USB) systems to share one display device are included, and USB devices connected to the display device and USB devices connected to the plurality of USB systems are shared, the method comprising, while output of a first predetermined USB system, among the plurality of USB systems, is transmitted to the display device, providing a predetermined menu to select a USB device to be shared and selecting a second predetermined USB system to connect to the selected USB device; if a menu item is selected, disabling a driver, which corresponds to the shared USB device in the first USB system; buffering information transmitted from the shared USB device in the display device; and transmitting the information, which is buffered in the display device, to the driver, which corresponds to the shared USB device, in the second USB system. 
   If the shared USB device is a keyboard or mouse, an input signal of the display device is switched so that output of the second USB system is transmitted to the display device. 
   The method further comprises releasing the shared USB device from the second USB system. 
   The releasing operation comprises, while output of the second USB system are transmitted to the display device, providing a predetermined menu to select a USB device to be released; if a menu item is selected, enabling a driver, which corresponds to the shared USB device, in the first USB system; and transmitting information, which is transmitted from the USB device, to a driver, which corresponds to the USB device, in the first USB system through the display device. 
   If the released USB device is a keyboard or mouse, an input signal of the display device is switched so that output of the first USB system are transmitted to the display device. 
   According to another aspect of the present invention, there is included a display apparatus, in which in a plurality of universal serial bus (USB) systems sharing one display device are included, and USB devices connected to the display device and USB devices connected to the plurality of USB systems are shared, wherein the apparatus includes a relay unit included in the display device, while output of a first predetermined USB system, among the plurality of USB systems is transmitted to the display device, the relay unit selects to share the USB device being used in the USB system with a second predetermined USB system, and if a driver, which corresponds to the shared USB device, in the first USB system is disabled, the relay unit buffers information transmitted from the shared USB device in the display device and transmits the information buffered in the display device to a driver corresponding to the shared USB device of the second USB system. 
   If the shared USB device is a keyboard or mouse, an input signal of the display device is switched so that output of the second USB system is transmitted to the display device. 
   If the USB device is released from the second USB system and if a driver, which corresponds to the shared USB device, in the first USB system is enabled, the relay unit transmits the information transmitted from the USB device to the driver, which corresponds to the USB device, in the first USB system. 
   Additional and/or other aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the preferred embodiments taken in conjunction with the accompanying drawings in which: 
       FIGS. 1A and 1B  are block diagrams illustrating the structure of a conventional display apparatus; 
       FIG. 2  is a block diagram illustrating the structure of a display apparatus according to an embodiment of the present invention; and 
       FIGS. 3A and 3B  are flowcharts illustrating a display method according to an embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Reference will now be made in detail to the present preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present invention by referring to the figures. 
     FIG. 2  is a block diagram illustrating the structure of a display apparatus according to the present invention. The display apparatus includes a first PC  200 ; first devices {circle around ( 1 )}, {circle around ( 2 )}, and {circle around ( 3 )}  204 ,  205 , and  206  connected to the first PC  200 ; a second PC  201 ; second devices {circle around ( 1 )}, {circle around ( 2 )}, and {circle around ( 3 )}  207 ,  208 , and  209  connected to the second PC  201 ; a monitor  203 ; a scanner  210  connected to the monitor  203 ; a printer  211  connected to the monitor  203 ; a keyboard  212  connected to the monitor  203 ; and a mouse  213  connected to the monitor  203 . The first PC  200  includes a first universal serial bus (USB) host  200 - 1  and a port  200 - 2  including first down ports {circle around ( 1 )}, {circle around ( 2 )}, {circle around ( 3 )}, and {circle around ( 4 )}  200 - 21 ,  200 - 22 ,  200 - 23 , and  200 - 24 . The second PC  201  includes a second USB host  201 - 1  and a port  201 - 2  including second down ports {circle around ( 1 )}, {circle around ( 2 )}, {circle around ( 3 )}, and {circle around ( 4 )}  201 - 21 ,  201 - 22 ,  201 - 23 , and  201 - 24 . The monitor  203  includes an image signal input unit  203 - 1 , a signal processing unit  203 - 2 , a display unit  203 - 3 , a monitor control unit  203 - 4 , a monitor USB hub  203 - 5 , and a relay unit  203 - 6 . The monitor USB hub  203 - 5  includes a USB hub control unit  203 - 51 , an upstream port  203 - 52 , and third down ports {circle around ( 1 )}, {circle around ( 2 )}, {circle around ( 3 )}, and {circle around ( 4 )}  203 - 53 ,  203 - 54 ,  203 - 55 , and  203 - 56 . The relay unit  203 - 6  includes a first buffer  203 - 61 , a first serial interface engine  203 - 62 , a control unit  203 - 63 , a second serial interface engine  203 - 64 , and a second buffer  203 - 65 . 
     FIGS. 3A and 3B  are flowcharts illustrating a display method according to the present invention. The display method according to the present invention comprises operations of determining whether a user requests to share a USB device with the second PC  201  ( 300 ), displaying a USB device that can be shared with the second PC  201  ( 301 ), selecting a USB device to be shared with the second PC  201  ( 302 ), selecting a PC to which the selected and shared USB device is to be connected ( 303 ), determining whether display switching is required ( 304 ), controlling an image signal input so that a monitor displays the corresponding PC screen ( 305 ), transmitting an ID of the selected and shared USB device to a control unit ( 306 ), requesting interrupt ( 307 ), determining whether the transmitted ID of the shared USB device exists ( 308 ), disabling a driver corresponding to the shared USB device in the former PC to which the shared USB device has been connected ( 309 ), determining whether data is transmitted from the shared USB device ( 310 ), recording the data in a second buffer after passing through a first buffer ( 311 ), determining whether data exists in the second buffer ( 312 ), decoding the type and ID of the USB device which has transmitted the data ( 313 ), transmitting data to a driver corresponding to the shared USB device of a new PC ( 314 ), displaying the currently shared USB device ( 315 ), selecting a USB device to be released ( 316 ), transmitting an ID of the released USB device to the control unit ( 317 ), requesting an interrupt ( 318 ), determining whether the transmitted ID of the released USB device exists ( 319 ), enabling a driver corresponding to the released USB device ( 320 ), and determining whether a shared USB device exists (not shown). 
   Hereinafter, the present invention will be described in detail with reference to  FIGS. 2 ,  3 A, and  3 B. 
   The first PC  200  and the second PC  201  described above are referred to as first and second USB systems in the following claims, and the monitor  203  described above is referred to as a display device. 
   The first and second PCs  200  and  201  share the monitor  203 . That is, when the user uses the first PC  200 , output of the first PC  200  is displayed on the monitor  203 , and when the user uses the second PC  201 , output of the second PC  201  is displayed on the monitor  203 . In the present invention, although the system sharing the monitor  203  discussed in relation to two PCs, such as the first and second PCs  200  and  201 , two or more PCs may be used. 
   The first USB host  200 - 1  of the first PC  200  controls USB communication between the first PC  200  and one of the first devices {circle around ( 1 )}, {circle around ( 2 )}, and {circle around ( 3 )},  204 ,  205 , and  206  connected to the first PC  200 . Here, the first devices {circle around ( 1 )}, {circle around ( 2 )}, and {circle around ( 3 )}  204 ,  205 , and  206  may each be a scanner, printer, keyboard, or mouse, and is not limited to the above example. The first USB host  200 - 1  includes a hub (not shown). The hub relays input/output data of the first devices {circle around ( 1 )}, {circle around ( 2 )}, and {circle around ( 3 )},  204 ,  205 , and  206  connected to the first PC  200  through the first down ports {circle around ( 1 )}, {circle around ( 2 )}, {circle around ( 3 )}, and {circle around ( 4 )}  200 - 21 ,  200 - 22 ,  200 - 23 , and  200 - 24 . 
   The second USB host  201 - 1  of the second PC  201  controls USB communication between the second PC  201  and one of the second devices {circle around ( 1 )}, {circle around ( 2 )}, and {circle around ( 3 )}  207 ,  208 , and  209  connected to the second PC  201 . Here, the second devices {circle around ( 1 )}, {circle around ( 2 )}, and {circle around ( 3 )}  207 ,  208 , and  209  may each be a scanner, printer, keyboard, or mouse, and is not limited to the above example. The second USB host  201 - 1  includes a hub (not shown). The hub relays input/output data of the second devices {circle around ( 1 )}, {circle around ( 2 )}, and {circle around ( 3 )}  207 ,  208 , and  209  connected to the second PC  201  through the second down ports {circle around ( 1 )}, {circle around ( 2 )}, {circle around ( 3 )}, and {circle around ( 4 )}  201 - 21 ,  201 - 22 ,  201 - 23 , and  201 - 24 . 
   The monitor  203  displays output from the first PC  200  or second PC  201 . The image signal input unit  203 - 1  receives an image signal transmitted from the first PC  200  or the second PC  201 . The signal processing unit  203 - 2  performs signal processing to display the transmitted image signal. The display unit  203 - 3  displays the signal-processed image signal. The monitor control unit  203 - 4  controls all operations performed so that received image signals are displayed, and controls each block of the monitor  203 . 
   The scanner  210 , the printer  211  and the keyboard  212  which are USB devices, are connected to the monitor  203  through the monitor USB hub  203 - 5 . The USB hub control unit  203 - 51  controls the third down ports {circle around ( 1 )}, {circle around ( 2 )}, {circle around ( 3 )}, and {circle around ( 4 )}  203 - 53 ,  203 - 54 ,  203 - 55 , and  203 - 56 , which enables connection of a USB device to each of the third down ports {circle around ( 1 )}, {circle around ( 2 )}, {circle around ( 3 )}, and {circle around ( 4 )}  203 - 53 ,  203 - 54 ,  203 - 55 , and  203 - 56  and enables transmission of a signal from a USB device to the upstream port  203 - 52 . The upstream port  203 - 52  is connected to the first down port {circle around ( 1 )}  200 - 21  of the first PC  200 , establishing USB communication between the first USB host  200 - 1  and the monitor  203 . 
   The relay unit  203 - 6  relays data transmission when the first PC  200  and the second PC  201  share a USB device. The first buffer  203 - 61  buffers the signal transmitted from the selected and shared USB device. The buffered signal is transmitted to the control unit  203 - 63  through the first serial interface engine  203 - 62 . The control unit  203 - 63  checks the ID of the shared USB device and transmits the buffered signal to the second buffer  203 - 65  through the second serial interface engine  203 - 64 . The second PC  201  accesses the second buffer  203 - 65 , receives data stored in the second buffer  203 - 65  transmitted through the second down port {circle around ( 4 )}  201 - 24  to the second USB host  201 - 1 , and drives a driver corresponding to the USB device. 
   The display method by which the first and second PCs  200  and  201  share different USB devices through the relay unit  203 - 6  of the monitor  203 , will be described with reference to  FIGS. 3A and 3B . 
   When the user uses the first PC  200 , output of the first PC  200  is transmitted to the monitor  203 . In this case, if it is assumed that the input device is the keyboard  212  and the mouse  213 , which are connected to the monitor  203 , then data input from the keyboard  212  and the mouse  213  is transmitted to the USB hub control unit  203 - 51  through the third down port {circle around ( 3 )}  203 - 55 . The USB hub control unit  203 - 51  outputs the data to the upstream port  203 - 52 , and the data is then transmitted to the first USB host  200 - 1  through the first down port {circle around ( 1 )}  200 - 21  of the first PC  200 . The first USB host  200 - 1  transmits the data to the drivers corresponding to the keyboard  212  and the mouse  213  and transmits the results of data processing to the image signal input unit  203 - 1  from the drivers corresponding to the keyboard  212  and the mouse  213 . The signal processing unit  203 - 2  performs signal processing on the data, which is output to the display unit  203 - 3 . 
   In operation  300 , it is determined whether the user requests to share a USB device with the second PC  201 . When the user uses the keyboard  212  and the mouse  213  as input devices to the first PC  200  and wishes to share the keyboard  212  and the mouse  213  with the second PC  201 , the user opens a share program stored in the first PC  200 . For example, the user might desire to share the keyboard  212  and the mouse  213  so as to perform CAD work in the second PC  201  while performing word processing in the first PC  200 . In this case, the first PC  200  can open the share program by clicking the right button on the mouse  213 . The share program is applied to both the first and second PCs  200  and  201 . 
   If the user using the first PC  200  selects the share program to share a USB device with the second PC  201 , then in operation  301 , the USB devices that can be shared with the second PC  201  are displayed on the monitor  203 . In the case of the first PC  200 , the first devices {circle around ( 1 )}, {circle around ( 2 )}, and {circle around ( 3 )}  204 ,  205 , and  206 ; the scanner  210 ; the printer  211 ; the keyboard  212 ; and the mouse  213  are displayed on the monitor  203 , and in the case of the second PC  201 , the second devices {circle around ( 1 )}, {circle around ( 2 )}, and {circle around ( 3 )}  207 ,  208 , and  209  are displayed on the monitor  203 . 
   In operation  302 , the displayed USB devices that can be shared with the second PC  201  are seen, and a USB device to be shared with the second PC  201  is selected. For example, if the user wants to share the keyboard  212  and the mouse  213  with the second PC  201  while using the first PC  200 , the USB devices selected are the keyboard  212  and the mouse  213 . 
   If a shared USB device is selected, then in operation  303 , a PC is selected to connect to the selected and shared USB device. If the keyboard  212  and the mouse  213  are the selected USB devices to be shared with the second PC  201 , the PC selected is the second PC  201 . 
   In operation  304 , it is determined whether display switching is required. It is determined whether the monitor  203  displaying the output of the first PC  200 , must display the output of the second PC  201 . 
   If display switching is required, in operation  305 , the image signal input is controlled so that the monitor  203  displays the corresponding USB host screen. When the shared USB device is the scanner  210  or printer  211 , display switching is not required. However, when the shared USB device is the keyboard  212  or the mouse  213 , the image signal input is controlled so that the output of the second PC  201  is transmitted to the monitor  203 . 
   After the PC is selected and display switching is performed, then in operations  306  and  307 , an ID of the selected and shared USB device is transmitted to the control unit  203 - 63  of the relay unit  203 - 6 , and an interrupt is requested. 
   In operations  308  and  309 , the control unit  203 - 63  of the relay unit  203 - 6  determines whether the transmitted ID of the shared USB device exists and, if the transmitted ID of the shared USB device exists, the driver corresponding to the shared USB device is disabled in the PC to which the shared USB device was initially connected. For example, the keyboard  212  and the mouse  213  are connected to the second PC  201  only after the first PC  200  disables drivers corresponding to the keyboard  212  and the mouse  213 . 
   In operations  310  and  311 , it is determined whether data is transmitted from the shared USB device. If data is transmitted, then the data is recorded in the second buffer  203 - 65  after passing through the first buffer  203 - 61 . The data input from the keyboard  212  and the mouse  213  is transmitted to the first USB host  200 - 1  through the third down port {circle around ( 3 )}  203 - 55 , the upstream port  203 - 52 , and the first down port {circle around ( 1 )}  200 - 21 . However, since the drivers corresponding to the keyboard  212  and the mouse  213  are disabled, data processing is not performed, and the data is recorded in the first buffer  203 - 61  of the relay unit  203 - 6  through the first down port {circle around ( 1 )}  200 - 21 , the upstream port  203 - 52 , and the third down port {circle around ( 4 )}  203 - 56 . Data of the keyboard  212  and the mouse  213  recorded in the first buffer  203 - 61  is serial data, and the serial data is converted into parallel data by the first serial interface engine  203 - 62  and transmitted to the control unit  203 - 63 . The control unit  203 - 63  checks the ID of the keyboard  212  and the mouse  213 , and the parallel data is then converted into serial data by the second serial interface engine  203 - 64  and buffered by the second buffer  203 - 65 . 
   In operation  312 , the second PC  201  frequently checks the second buffer  203 - 65  and determines whether any data exists in the second buffer  203 - 65 . 
   If data exists in the second buffer  203 - 65 , then in operation  313 , the type and ID of the USB device, which has transmitted the data, are decoded. 
   In operation  314 , the data is transmitted to the driver in the second PC  201 , corresponding to the shared USB device. Data from the keyboard  212  and the mouse  213  stored in the second buffer  203 - 65  is transmitted to the second USB host  201 - 1  through the second down port {circle around ( 4 )}  201 - 24 . The second USB host  201 - 1  operates the drivers corresponding to the keyboard  212  and the mouse  213  using the transmitted data. 
   When the user wants to release the shared USB device, the user opens the share program stored in the first PC  200  or second PC  201 . The first PC  200  can open a share release program by clicking the right button on the mouse  213 . The share program is applied to both the first PC  200  and the second PC  201 . 
   When the user of the first PC  200  selects the share program to release the USB device from the second PC  201 , then in operation  315 , the USB device currently shared is displayed on the monitor  203 . In the case of the first PC  200 ; the first devices{circle around ( 1 )}, {circle around ( 2 )}, and {circle around ( 3 )}  204 ,  205 , and  206 ; the scanner  210 ; the printer  211 ; the keyboard  212 ; and the mouse  213  are displayed on the monitor  203 , and in the case of the second PC  201 , the second devices {circle around ( 1 )}, {circle around ( 2 )}, and {circle around ( 3 )}  207 ,  208 , and  209  are displayed on the monitor  203 . 
   In operation  316 , a USB device is selected to be released from the second PC  201 . For example, if the user shares the keyboard  212  and the mouse  213  with the first and second PCs  200  and  201  and wishes to release the second PC  201  from the keyboard  212  and the mouse  213 , the USB devices selected are the keyboard  212  and the mouse  213 . 
   If a USB device is selected to be released, in operations  317  and  318 , it is determined whether display switching is required. If display switching is required, display switching is performed, and then an ID of the released USB device is transmitted to the control unit  203 - 63 , and an interrupt is requested. 
   In operations  319  and  320 , the control unit  203 - 63  of the relay unit  203 - 6  determines whether the transmitted ID of the released USB device exists. If the transmitted ID of the released USB device exists, a driver corresponding to the released USB device is enabled in the PC to which the released USB device is still connected. For example, the keyboard  212  and the mouse  213  are released from the second PC  201 , and thus, the first PC  200  enables drivers corresponding to the keyboard  212  and the mouse  213 . After that, the data input from the keyboard  212  and the mouse  213  is transmitted to the first USB host  200 - 1  through the third down port {circle around ( 3 )}  203 - 55 , the upstream port  203 - 52 , and the first down port {circle around ( 1 )}  200 - 21 . 
   As described above, the display apparatus and method, according to the present invention automatically perform screen switching and switching of an input device thereof and share between several PCs a universal serial bus (USB) device connected to a monitor hub and a USB device connected to a PC body, when several PCs are connected to one monitor. 
   Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in this embodiment without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.