Image display apparatus in which a specific area display attribute is modifiable

• US 20040080515A1
• Filed: 10/25/2002
• Published: 04/29/2004
• Est. Priority Date: 10/25/2002
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Hagiwara, Kunihiko
• Granted Patent: US 6,999,092 B2
• Time in Patent Office: Days
• US Class Current: 345/581
• CPC Class Codes: G09G 2320/0686 with two or more screen areas displaying information with different brightness or colours
• CPC Class Codes: G09G 2340/0464 Positioning
• CPC Class Codes: G09G 2370/04 Exchange of auxiliary data, i.e. other than image data, between monitor and graphics controller
• CPC Class Codes: G09G 5/005 Adapting incoming signals to the display format of the display terminal
• CPC Class Codes: G09G 5/006 Details of the interface to the display terminal specific for a display terminal using a CRT G09G1/167; using a flat panel G09G3/2096; circuits for interfacing with colour displays G09G5/04
• CPC Class Codes: G09G 5/18 Timing circuits for raster scan displays specially adapted for television H04N ; synchronisation between the display unit and other display units, videodisc player G09G5/12

Abstract

In an image display apparatus in which a display attribute of a specific area of the display can be modified based on an information input from a processor, a resolution of the image is determined from the input vertical and horizontal synchronization signals, dot clocks are generated by multiplying the horizontal synchronization signals depending on the determined resolution, a horizontal display period in one horizontal synchronization signal is detected using a signal in the image signals input from the processor, the actual count value of the dot clocks in the detected horizontal display period is compared with a standard value thereof in the horizontal display period in one line at the determined resolution of the image and the multiplication number of a dot clock generation circuit is corrected so that the count value coincides with the standard value to modify the display attribute of the specific area of the display.

Claims

1. An image display apparatus in which a display attribute of a specific area of the display can be modified based on an image signal input from an information processor, vertical and horizontal synchronization signals, and position information and display attribute information of the specific area, comprising:

a resolution determination circuit which determines the resolution of the displayed image, based on the input vertical and horizontal synchronization signals,

a dot clock generation circuit which generates dot clocks by multiplying the horizontal synchronization signal according to the determined resolution of the image,

a horizontal display period detection circuit which detects a horizontal display period in one horizontal synchronization signal, using a signal in the image signal input from the information processor,

dot clock counting circuit which actually counts the number of the dot clocks detected in the horizontal display period,

a dot clock standard value reading circuit which reads a standard value of the number of the dot clocks in the horizontal display period in a line at the determined resolution of the displayed image, and

a correction circuit which corrects the multiplication number in the dot clock generation circuit so that the actually counted dot clock number is identical to the standard value.

2. An image display apparatus according to claim 1 in which one signal of the image signals for detecting the horizontal display period in one horizontal synchronization signal is one of the RGB signals.

3. An image display apparatus according to claim 1 in which, if the number of the counted dot clocks is slightly different from the standard value, the correction circuit judges that the number of the counted dot clocks is equal to the standard value.

4. An image display apparatus according to claim 3 in which the slight difference between the number of the counted dot clocks and the standard value corresponds to one pulse of the dot clock.

5. An image display apparatus according to claim 1 in which the multiplication number is corrected by the correction circuit by dividing the standard value of the dot clock number by the actually counted number of the dot clocks, and multiplies the quotient by a current multiplication number of the dot clocks to thereby obtain a multiplication number.

6. An image display apparatus according to claim 1 in which the display is a CRT display.

7. An image display apparatus according to claim 1 in which the display is a liquid crystal display with an analogue interface.