The utility model particularly relates to a backlight unit, display screen and display device. Wherein, backlight unit is including the blue light LED lamp strip, light guide plate, reflection subsides and the quantum rete that are used for sending the blue light. The first side of light guide plate is for going into the plain noodles, and sets up relatively with blue light LED lamp strip, is provided with the reflection on the second side of light guide plate and pastes, and the reflection is pasted an one side that is close to the light guide plate and is provided with the blue light and handles the layer, and the blue light is handled the layer and is used for absorbing the blue light, or by the blue light excite and the mixed light after form the white light, be provided with the quantum tunic on the play plain noodles of light guide plate, the intraformational quantum dot of quantum membrane excited by the blue light that jets out from the light guide plate and the mixed light after form the white light. The utility model discloses a be provided with the blue light in the one side that the light guide plate paste to be close to in the reflection and handle the layer, the bluelight handle the layer be used for absorbing the blue light or by the blue light arouse and the mixed light after form the technological means of white light, realized the technological effect of eliminating backlight unit blueing limit, solved the technical problem who appears blue limit on the current backlight unit.