The "i" stands for interlaced and "p" stands for progressive. 1080i and 1080p/720p represent two different methods used to display HDTV video on a screen.
When video is interlaced, a single video frame only draws every other line. If you numbered each horizontal line in a 1080i frame from 1 (as the top line) to 1080 (as the bottom line), each successive video frame alternates between drawing the odd-numbered lines and the even-numbered lines. Therefore, a display supporting a 1080i format may draw all of the odd-numbered lines (totaling 540 lines) in one frame, and then draw the 540 even-numbered lines in the next frame. This format is used by CBS and NBC.
A display supporting 1080 or 720 progressive format will sequentially draw all 1080 or 720 lines in each frame. You will notice a difference in picture depending on whether the program is being shown using the progressive or interlaced method. ABC and FOX use the 720p format.
All of Sharp's LCD TV models, with the exception of the LC-15L1U-S, are able to display a 480p signal (progressive scan). Many models, including some 20" models and all 26" and larger models, can display a 720p/1080i signal. Sharp's current 45" AQUOS models and the new 65" LC-65D90U can display a 1080p signal, the highest resolution in the DTV spectrum.
