Display device and display method
A display device having an on-screen display (OSD) function receives a YUV video signal such as the camera video signal or broadcast video signal of YUV format from a camera or recording medium, receives an RGB-OSD signal from a circuit device (serial interface) of another system different from this YUV video signal, causes a memory within an OSD processor to store the OSD signal, converts an RGB video signal resulting from conversion of the YUV video signal to a panel-matched RGB video signal synchronized with a display synchronization signal, reads a panel-matched RGB OSD signal from the memory of the OSD processor in synchronism with this display synchronization signal, composes those RGB video signal and OSD signal, using an OSD composer, and supplies the resulting RGB composite video signal and the display synchronization signal to a display panel.
1. A display device comprising:
a display panel having an array of display elements;
a signal processor that responds to control information and to a display synchronization signal generated from said control information to produce a panel-matched video signal and panel-matched on-screen display (OSD) signal of which the resolutions correspond to that resolution of said display panel, and that produces at an output of the signal processor a composite video signal of said panel-matched video signal and said panel-matched OSD-signal together with said display synchronization signal;
a scanning circuit that produces an output of a scanning signal in synchronism with said display synchronization signal produced from said signal processor so as to select ones of said arrayed display elements of said display panel; and
a drive circuit that uses said composite video signal and said display synchronization signal produced from said signal processor to drive said display elements selected by said scanning signal produced from said scanning circuit, said signal processor comprising:
a conversion circuit which converts the format of an inputted video signal;
a panel-matched conversion circuit which converts a video signal produced from said conversion circuit to said panel-matched video signal;
an OSD processing circuit which converts an inputted OSD signal to said panel-matched OSD signal;
a synchronization signal generation circuit which supplies said control information and said display synchronization signal to said panel-matched conversion circuit and said OSD processing circuit; and
an OSD composing circuit which composes said panel-matched video signal and said panel-matched OSD signal.
2. A display device according to claim 1 , wherein said OSD processing circuit comprises:
a compression circuit which compresses said panel-matched OSD signal or said OSD signal;
a memory which stores said compressed panel-matched OSD signal or said compressed OSD signal;
a restoration circuit which restores said compressed panel-matched OSD signal or said compressed OSD signal read from said memory to the original signals; and
an OSD panel-matched conversion circuit which converts the resolution of said OSD signal or said restored OSD signal to a resolution corresponding to the resolution of said display panel, and
the OSD signal which is inputted asynchronously with said inputted video signal is synchronized with said display synchronization signal.
3. A display device according to claim 2 , wherein when said control information indicates that the amount of one-frame data of said OSD signal is larger than that necessary to display on said display panel, said OSD panel-matched conversion circuit converts the resolution of said OSD signal to a resolution corresponding to the resolution of said display panel before said OSD signal is stored in said memory.
4. A display device according to claim 2 , wherein when said control information indicates that the amount of one-frame data of said OSD signal is smaller than that necessary to display on said display panel, said OSD panel-matched conversion circuit converts the resolution of said OSD signal to a resolution corresponding to the resolution of said display panel after said OSD signal is read from said memory.
5. A display device according to claim 2 , wherein when said control information contains a value for specifying a displaying position, said OSD panel-matched conversion circuit converts said value for specifying said displaying position to a value for specifying a displaying position on said display panel.
6. A display device according to claim 1 , wherein said OSD signal is supplied asynchronously with said inputted video signal when the OSD signal is inputted to said display device, and then said OSD signal is displayed in synchronism with said video signal when the OSD signal is supplied to said display panel.
7. A display device according to claim 1 , wherein the format of said inputted OSD signal is different from the format of said inputted video signal, but the format of said OSD signal to be displayed on said display panel is the same as the format of said video signal to be displayed on said display panel.
8. A display device according to claim 7 , wherein
the format of said inputted video signal is a YUV format,
the format of said inputted OSD signal is an RGB format, and
the format of said OSD signal to be displayed on said display panel and the format of said video signal to be displayed on said display panel are both RGB format.
9. A display device according to claim 1 , wherein said signal processor comprises:
a first input port for receiving said inputted video signal; and
a second input port for receiving said inputted OSD signal.
10. A display device for composing a first video signal and a second video signal and displaying the resulting composite video signal, comprising:
a display panel;
a signal processor which processes said first and second video signals; and
a drive circuit which drives said display panel to display said processed first and second video signals, wherein
the format of said first video signal fed to said display device is different from that of said second video signal fed to said display device,
said second video signal is supplied to said display device asynchronously with said first video signal,
said second video signal is displayed on said display panel in synchronism with said first video signal, and
said signal processor converts the format of said second video signal to the same format as that of said first video signal, makes said first video signal be synchronized with said second video signal, and composes said synchronized first video signal and said converted second video signal.
11. A method comprising steps of:
converting a video signal and an OSD signal to a panel-matched video signal and a panel- matched OSD signal on the basis of control information, respectively,
composing said panel-matched video signal and said panel-matched OSD signal to produce a composite video signal, and
causing a display panel to display said composite video signal in synchronism with a display synchronization signal derived from said control information, wherein:
the converting of said video signal into said panel-matched video signal is based on said display synchronization signal, and
the converting of said OSD signal into said panel-matched OSD signal is based on said display synchronization signal.
12. A method according to claim 11 , further comprising:
converting the format of said video signal, wherein the converted video signal is converted to said panel-matched video signal on the basis of said control information after the conversion of the format of said video signal.
13. A method according to claim 11 , further comprising compressing said OSD signal or said panel-matched OSD signal.