| 摘要 |
An apparatus is provided for magnifying the image of distant objects which has the unique feature that objects to be viewed can be at any arbitrarily large distance from the apparatus. In addition, the apparatus does not require positioning of the eye at the exit pupil of the instrument; it does not require centering of the eye on the optic axis of the instrument; and it does not require refocusing for different object distances. Still, it provides erect, non-inverted images to the viewer. The invention includes a positive optical element (53) defining an optic axis for the apparatus and having a positive focal length for converging an incoming bundle of rays of electromagnetic radiation. Also included is a negative optical element (51) aligned with the optic axis and separated from said positive optical element by a distance d1, with the negative optical means having a negative focal length that is substantially equal in magnitude to the focal length of the positive optical means and having a focal point on the optic axis. |
