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

A reflective eyepiece optical system, composed of a first optical element and a second optical element arranged successively in 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<−0.47 (1);
• −2.53<f2/fw<−0.64 (2);
• the first lens group comprises a first sub-lens group, a second sub-lens group, a third sub-lens group, and a fourth sub-lens group arranged coaxially and successively along the optical axis from a human eye viewing side to the miniature image displayer side;
• effective focal lengths of the first sub-lens group, the second sub-lens group, and the third sub-lens group are a combination of positive, negative and positive;
• the effective focal length of the first sub-lens group is f11, the effective focal length of the second sub-lens group is f12, the effective focal length of the third sub-lens group is f13, and f11, f12, f13, and f1 satisfy the following relations (3), (4), and (5):
• 0.19<f11/f1 (3);
• f12/f1<−0.019 (4);
• 0.019<f13/f3 (5).