Abstract: A display device (4) for a telescope system is disposed between a first image plane (10) and a second image plane (20) of the telescope system. The display device includes a signal emitter (41), a converging lens group (42) positioned adjacent to the signal emitter, and a dioptric imaging lens group (43) positioned adjacent to the converging lens group. The optical signal emitted by the signal emitter is first transmitted through the converging lens group, then incident onto the dioptric imaging lens group, and finally imaged onto the second image after reflection of the dioptric imaging lens group. Therefore, both the image size and brightness of the displayed signal viewed by the observer can maintain unchanged in spite of the magnification variation of the telescope system.

Abstract: A display device (4) for a telescope system is disposed between a first image plane (10) and a second image plane (20) of the telescope system. The display device includes a signal emitter (41), a converging lens group (42) positioned adjacent to the signal emitter, and a dioptric imaging lens group (43) positioned adjacent to the converging lens group. The optical signal emitted by the signal emitter is first transmitted through the converging lens group, then incident onto the dioptric imaging lens group, and finally imaged onto the second image after reflection of the dioptric imaging lens group. Therefore, both the image size and brightness of the displayed signal viewed by the observer can maintain unchanged in spite of the magnification variation of the telescope system.

Abstract: An eyepiece lens group in a riflescope system comprises, from a front, eye side to a rear, object side, a glass lens and a plastic lens. The plastic lens has an aspherical surface and a diffractive surface, wherein the diffractive surface is on the front surface of the plastic lens and the aspherical surface is on the rear surface of the plastic lens. The aspherical surface of the plastic lens is utilized to abate the aberration. The diffractive surface of the plastic lens is utilized to abate the chromatic aberration. Therefore, the total numbers of lenses of the eyepiece lens group in the riflescope system could be reduced and the weight of the riflescope system could be reduced.