Jepsen has described the removal of the filters that color the RGB subpixels as the critical design innovation in the new LCD. Instead of using subtractive color filters, the display uses a plastic diffraction grating and lenses on the rear of the LCD to illuminate each pixel. This grating pattern is stamped using the same technology used to make DVDs. The grating splits the light from the white backlight into a spectrum. The red, green and blue components are diffracted into the correct positions to illuminate the corresponding pixel with R, G or B. This innovation results in a much brighter display for a given amount of backlight illumination: while the color filters in a regular display typically absorb 85% of the light that hits them, this display absorbs little of that light. Most LCD screens at the time used cold cathode fluorescent lamp backlights which were fragile, difficult or impossible to repair, required a high voltage power supply, were relatively power-hungry, and accounted for 50% of the screens' cost (sometimes 60%). The LED backlight in the XO-1 is easily replaceable, rugged, and inexpensive.