Light control system for windshield

A light control system for a windshield comprising:

• a windshield of a vehicle, the windshield being capable of changing a visible light transmittance of an upper part and a non-upper part;
• and
• a controller that controls a change of the visible light transmittance, wherein
• when the vehicle is not in a driving state, the controller permits a change of reducing the visible light transmittance of the upper part and the non-upper part to be lower than a predetermined value,
• when the vehicle is in a driving state, the controller controls the visible light transmittance of the upper part to be freely selectable in a first changeable range that is set in advance and includes a visible light transmittance lower than the predetermined value, and controls the visible light transmittance of the non-upper part to be selectable only in a range having a visible light transmittance equal to or higher than the predetermined value within a second changeable range that is set in advance and includes a visible light transmittance lower than the predetermined value, and
• when the vehicle is in the driving state, the controller permits a change of reducing the visible light transmittance of the upper part to be lower than the predetermined value and prohibits a change of reducing the visible light transmittance of the non-upper part to be lower than the predetermined value.