Headlight device

A headlight device, comprising:

• a light source disposed on a circuit board, and the light source has a light emitting surface;
• a reflector disposed on a side of the circuit board and covering the light source, the reflector has a reflecting surface, the reflecting surface facing the light emitting surface, an opening formed by a side of the reflecting surface, and an angle between a direction of the opening and the normal line of the light emitting surface equal to or greater than 90 degrees;
• a Fresnel lens located on a side of the opening opposite to the light source;
• and
• a blocking plate;
• wherein a light beam emitted from the light emitting surface is reflected by the reflecting surface and then passes through the Fresnel lens, the light beam converges towards an energy convergence area on a vertical plane, the blocking plate is located between the vertical plane and the light source in order to block part of the light beam so as to create a light pattern having a cut-off line;
• wherein a reference plane is defined to perpendicular to the opening, an optical axis of the light source is on the reference plane, the reflecting surface and the reference plane intersect at a curved line on the reflecting surface, and the curved lined line has an opening end and a connecting end opposite to each other, the connecting end is located on a side of the reflector close to the circuit board, the curved line is defined by a quadratic Bezier curved function, and the quadratic Bezier curved function comprises:
• Bx(t)=(1−t)2P0x+2t(1−t)P1x+t2P2x, t∈[0,1];
• and
• By(t)=(1−t)2P0y+2t(1−t)P1y+t2P2y, t∈[0,1];
• wherein the connecting end is an origin of a coordinate, the X-coordinate and the Y-coordinate of the connecting end are respectively P0x and P0y, the X-coordinate and the Y-coordinate of the opening end are respectively P2x and P2y, the X-coordinate and the Y-coordinate of a reference point in adjusting the curvature of the curved line are respectively P1x and P1y, the coefficient in determining any point on the curved line is t, and the X-coordinate and the Y-coordinate of any point on the curved line are respectively Bx(t) and By(t).