Apple Patent Application: “Backlight Unit Color Compensation Techniques”

AppleInsider:

Apple’s solution would address the issues associated with edge-lit backlights for LCD displays by utilizing a “light guide” Coupled with a “light-extracting surface area,” it could compensate for color shift issues found with current edge-lit displays, like those found in Apple’s MacBook Pro notebooks.

The problem: phosphor-coated white LED light has a blue-ish tint in short distances and turns yellow-ish the longer it travels. This variation affects color uniformity on a LCD using a white LED-based backlight unit. This patent thoroughly mixes the light to make sure light hitting the color filter is uniform in color.