LCD controller to hold a fixed image aspect ratio

Abstract

A circuit and a method for maintaining the aspect ratio of images when there is a difference in format between image sources and display panels is provided. Lines are added in the vertical direction both at the top and at the bottom of the display panel in order to make the display panel have the same aspect ratio as the input image. A line enable signal is used to expand the vertical lines to maintain aspect ratio. Previously, the period of line enable signals could not be programmed to vary sufficiently to yield the necessary expansion to allow the aspect ratio of the display panel image to match the aspect ratio of the source image. This design allows the period of the line enable signal to vary enough to match all reasonable aspect ratios of input images.

1 . A method of scaling an image for a display comprising the steps: 
 providing a source image having an aspect ratio,    adding blank vertical lines at the top and bottom of the source image so that a resulting image has a second aspect ratio, and    upscaling the resulting image to a larger x/y dimension while maintaining the second aspect ratio.    
   
   
       2 . The method of scaling an image for a display of  claim 1  wherein a line enable, LE, signal is expanded at top side of said resulting image.  
   
   
       3 . The method of scaling an image for a display of  claim 1  wherein a line enable, LE, signal is expanded at bottom side of said resulting image.