Patent ID: 6333751
Filing Date: 2001-12-25
Classification: G09G

Abstract:
A multiscanning type display apparatus comprising:a matrix drive type display that has a predetermined number of display lines and displays a picture signal;a picture signal supplier that supplies the picture signal to the matrix drive type display device;a synchronization signal supplier that outputs a synchronization signal included in the picture signal;a frequency extractor that extracts a horizontal frequency and a vertical frequency from the synchronization signal;a change ratio memory that stores a plurality of change ratios for converting a resolution of the picture signal into a resolution of the matrix drive type display device and a plurality of pairs of a horizontal frequency and a vertical frequency, each of the plurality of change ratios being associated with one of the plurality of pairs of a horizontal frequency and a vertical frequency, each pair corresponding to one of a plurality of resolutions of picture signals supplied by the picture signal supplier;a change ratio reader that compares at least one of the horizontal and vertical frequencies extracted by the frequency extractor with the plurality of pairs of the vertical frequency and the horizontal frequency stored in the change ratio memory in order to specify the picture signal supplied by the picture signal supplier, and retrieves one of the plurality of change ratios corresponding to the specified picture signal;a resolution changer that executes a resolution change by multiplying the picture signal by the change ratio retrieved by the change ratio reader;a total-line-number calculator that calculates a total number of lines of the picture signal by dividing the horizontal frequency by the vertical frequency extracted by the frequency extractor when the change ratio reader does not retrieve one of the plurality of change ratios corresponding to the specified picture signal;a resolution memory that stores a plurality of numbers of display lines each corresponding to one of a plurality of resolutions used in the picture signal supplier;a resolution selector that retrieves one of the plurality of numbers of display lines from the resolution memory in accordance with the total number of lines of the picture signal;a change ratio calculator that calculates a change ratio to convert the number of display lines retrieved by the resolution selector into the predetermined number of display lines of the matrix drive type display device; andthe resolution changer further executing the resolution change by multiplying the picture signal by the change ratio calculated by the change ratio calculator.