| CPC G02B 25/001 (2013.01) [G06F 1/163 (2013.01)] | 13 Claims |
|
1. An eyepiece optical system, comprising a first lens group, a second lens group, a third lens group, and a fourth lens group arranged coaxially and sequentially in an optical axis direction from an observation side of human eyes to a micro-image display side, wherein an effective focal length of the first lens group is F1, and F1 is a positive value, an effective focal length of the second lens group is F2, and F2 is a negative value, an effective focal length of the third lens group is F3, and F3 is a positive value, an effective focal length of the fourth lens group is F4, and an effective focal length of the eyepiece optical system is F, and F1, F2, F3, F4, and F meet the following relational expressions (1), (2), (3), and (4):
0.92≤F1/F≤1.20 (1);
−0.84≤F2/F≤−0.49 (2),
1.01≤F3/F≤1.44 (3);
0.90≤F4/F≤2.88 (4);
the first lens group is composed of two lenses, namely a first lens close to a human eye side and a second lens away from the human eye side, and both the first lens and the second lens are positive lenses; the second lens group is composed of two lenses, namely a third lens adjacent to the first lens group and a fourth lens away from the human eye side, and both the third lens and the fourth lens are negative lenses; the third lens group is composed of one lens, wherein the third lens group comprises a fifth lens adjacent to the second lens group, and the fifth lens is a positive lens; and the fourth lens group is composed of two lenses, namely a sixth lens adjacent to the third lens group and a seventh lens away from the human eye side;
material properties of the various lenses in the eyepiece optical system meet the following relational expressions (5) and (6):
1.63≤Nd≤2.00 (5);
20.4≤Vd≤54.90 (6)
wherein Nd is a refractive index of each lens in the eyepiece optical system on a d-line, and Vd is an Abbe number of each lens in the eyepiece optical system on the d-line.
|