エッジライト型、直下型

Backlight, Wikipedia
"Most LED backlights for LCDs are edge-lit（エッジライト型）, i.e. several LEDs are placed at the edges of a lightguide, which distributes the light behind the LC panel. Advantages of this technique are the very thin flat-panel construction and low cost. A more expensive version is called full-array or direct（直下型）LED and consists of many LEDs placed behind the LC panel (an array of LEDs), such that large panels can be evenly illuminated. This arrangement allows for local dimming to obtain darker black pixels depending on the image displayed."