Illuminating device and a method for optimizing the light pattern

An illuminating device, comprising:

• a lamp case having a lighting space;
• a light-reflecting cup, located in the lighting space and including a light incident side and a light emergent side wherein the light-reflecting cup includes a light reflecting portion having a lower narrow light processing portion and upper wide light processing, portion;
• a light source, located m the lighting space and corresponding to the light incident side of the light reflecting cup, and light emitted by the light source corresponds to the lower narrow light processing portion and the upper wide light processing portion;
• and
• a cylindrical lens, located in the lighting space and corresponding to the light emergent side of the light reflecting cup;
• wherein one surface of the cylindrical lens has a plurality of convex columns extending from top to bottom, and each convex column faces the light emergent side;
• wherein, when the light source emits the light, a main bright area of a light pattern reflected by the light reflecting portion of the light reflecting cup is wide at the top and narrow at the bottom;
• wherein the light source includes a high beam light source, the light reflecting portion includes a high beam light processing portion, and the high beam light source corresponds to the high beam light processing portion.