Backlight unit, backlight module, reflection structure and display device

The embodiment of the utility model provides a backlight unit, a backlight module, a reflection structure and a display device. The backlight unit comprises a substrate base plate; the plurality of light-emitting parts are arranged on one side of the substrate; the reflector plate is arranged on the side, facing the light-emitting parts, of the substrate, a plurality of openings are formed in the reflector plate, the openings correspond to the light-emitting parts one to one so that light of the light-emitting parts can be emitted, and in the first direction, the outer boundary of the reflector plate shrinks inwards by a first preset distance towards the center of the backlight unit relative to the corresponding outer boundary of the substrate, the outer boundary is the outermost boundary perpendicular to the first direction. According to the technical scheme, in the cutting process of the backlight unit, the reflector plate cannot be cut, poor cutting of the reflector plate is avoided, and the production yie