Light-guide optical element

A light-guide optical element, comprising:

• a transparent light-guide body comprising a side surface facing a first direction, and a first surface and a second surface which are adjacent to the side surface and face each other, and the transparent light-guide body further comprising:
• a first inclined surface disposed in the transparent light-guide body and extending from the first surface to the second surface, the first inclined surface forming a first angle with the first surface, and a geometric center of the first inclined surface and a geometric center of the side surface are spaced apart with a first distance;
• a second inclined surface disposed in the transparent light-guide body and located at the other side of the first inclined surface facing the side surface, the second inclined surface extending from the first surface to the second surface and forming a second angle with the first surface, and a geometric center of the second inclined surface and the geometric center of the first inclined surface are spaced apart with a second distance;
• a third inclined surface disposed in the transparent light-guide body and located at the other side of the second inclined surface facing the first inclined surface, the third inclined surface extending from the first surface to the second surface, the third inclined surface forming a third angle with the first surface, and a geometric center of the third inclined surface and the geometric center of the second inclined surface are spaced apart with a third distance;
• a first reflective layer disposed on the first inclined surface;
• and
• a second reflective layer disposed on the second inclined surface;
• wherein the side surface is configured as an light receiving surface to receive an input light in a direction parallel to the first direction, such that the input light enters the transparent light-guide body from the side surface and travels within the transparent light-guide body without being reflected by the first surface or the second surface, and the input light is sequentially and partially reflected by the first inclined surface, the second inclined surface and the third inclined surface to form an output light output from the first surface of the transparent light-guide body,
• wherein the first distance is shorter than the second distance, and the second distance is longer than the third distance, and
• wherein a reflectance of the first reflective layer is 5% to 15%, and a reflectance of the second reflective layer is 20% to 30%.