Reflective eyepiece optical system and head-mounted near-to-eye display device

A reflective eyepiece optical system, which is composed of a first optical element and a second optical element which are arranged sequentially along an incident direction of an optical axis of human eyes, and a first lens group located on an optical axis of a miniature image displayer;

• wherein the first optical element is used for transmitting and reflecting an image light from the miniature image displayer;
• the second optical element comprises an optical reflection surface, and the optical reflection surface is concave to the human eyes;
• the first optical element reflects the image light refracted by the first lens group to the second optical element, and then transmits the image light reflected by the second optical element to the human eyes;
• an effective focal length of the eyepiece optical system is fw, an effective focal length of the first lens group is f1, an effective focal length of the second optical element is f2, and fw, f1, and f2 satisfy the following relations (1) and (2):
• f1/fw<−0.50 (1);
• f2/fw<−0.70 (2);
• the first lens group is composed of a first sub-lens group and a second sub-lens group arranged sequentially along an optical axis direction from a human eye viewing side to a miniature image displayer side;
• an effective focal length of the first sub-lens group is f11, which is a positive value;
• an effective focal length of the second sub-lens group is f12, which is a positive value;
• and f11, f12 and f1 satisfy the following relations (3) and (4):
• 0.66<f11/f1 (3);
• 0.57<f12/f1 (4);
• the first sub-lens group is composed of two lenses which are a first lens away from the miniature image displayer side and a second lens close to the miniature image displayer side respectively;
• the first lens is a negative lens;
• the second lens is a positive lens;
• and the second sub-lens group is composed of a third lens located between the second lens and the miniature image displayer, and the third lens is a positive lens.