Patent ID: 7885005

Claim:
An eyepiece system comprising: a basic lens group in which a lens having a negative refractive power and a lens having a positive refractive power are joined, the basic lens group as a whole having a positive refractive power; and at least one diffraction optical element; the diffraction optical element including a first diffractive element piece having a first diffractive optical surface, and a second diffractive element piece having a second diffractive optical surface; the first diffractive element piece and the second diffractive element piece being arranged so that the first diffractive optical surface and the second diffractive optical surface face each other; and the following conditional expressions being satisfied: when DH 1≦ DH 2, DH 1 /DH 1 H 2≦0.5 when DH 1 >DH 2, DH 2 /DH 1 H 2≦0.5 where DH 1 H 2 is the absolute value of the distance on an optical axis between a front principal point and a rear principal point of the eyepiece system positioned between an image surface and an eye point; DH 1 is the absolute value of a distance on the optical axis between a front principal point and the first diffractive optical surface of the eyepiece system positioned between the image surface and the eye point; and DH 2 is the absolute value of a distance on the optical axis between a rear principal point and the first diffractive optical surface of the eyepiece system positioned between the image surface and the eye point.