floodlight; floodlight projector
Technical term for a lighting device that projects a broad, intense beam, used in stadiums, construction sites, or outdoor events.
Floodlights are used at construction sites for nighttime work.
The stadium floodlights came on all at once.
投光器 is a more common, shorter term for a floodlight or projector, while 投光照明器 explicitly includes the lighting (照明) aspect and sounds more technical.
Compound of 投光 (projecting light) + 照明 (illumination) + 器 (device). A straightforward technical coinage.