LCD is the panel technology in most commercial displays. A liquid crystal layer selectively blocks light from a backlight, which is almost always LED, which is why "LED screen" and "LCD screen" usually describe the same object.
For signage it is the default for good reasons: mature, available in every size, bright enough for most indoor environments, and by far the best value per square metre. Commercial-grade LCD is what the overwhelming majority of menu boards, wayfinding screens and corporate displays actually are.
The caveat is black level and viewing angle. Because the backlight is always on, black is really very dark grey, and in a dim room that greyness is visible, which is where OLED wins. Off-axis, contrast and colour shift, so a screen mounted high and viewed from below looks worse than it measures.
The related trap is image persistence. LCD does not burn in the way OLED does, but a static element left for months can leave a faint temporary ghost. It usually clears; on a menu board running the same layout for years, sometimes it does not.