Abstract: A compact Keplerian optical system includes a telescope having an image-rotator (Pechan roof prism pair), and an eyepiece and objective lens operative to form an intermediate image plane within the image-rotator, thereby decreasing the overall length. The objective lens optionally forms part of a replaceable cap, and plurality of replaceable caps may be provided, each with a different focal length to adjust for working distance. In the preferred embodiments, the eyepiece includes a singlet and a doublet lens to minimize eyestrain, and the objective lens includes a doublet and singlet field lens operative to increase depth of field and field of view. A practical implementation includes a pair of the telescopes, one for each eye of a user. Such a configuration may take the form of loupes mounted relative to eyeglass frames for surgical, medical or dental viewing applications.

Abstract: A head-mounted illuminator, particularly suited to surgical, medical and dental applications, includes a housing with a hollow interior having a light-receiving end and a light-projecting end. An optical fiber or fiber bundle is used to carry light from the source of light into the interior of the housing through the light-receiving end, and a Fresnel lens, mounted in the light-projecting end of the housing, receives light from the optical fiber and projects the light into a field of view. The Fresnel lens is constructed from acrylic material, enabling the design to focus and concentrate visible light. In the preferred “grooves in” embodiment, the light-projecting end and the light-receiving end of the housing are connected with a threaded coupling, enabling the light-projecting end to be moved forward and backward relative to the light-receiving end to adjust the light projected into the field of view.

Abstract: A compact Keplerian optical system includes a telescope having an image-rotator (Pechan roof prism pair), and an eyepiece and objective lens operative to form an intermediate image plane within the image-rotator, thereby decreasing the overall length. The objective lens optionally forms part of a replaceable cap, and plurality of replaceable caps may be provided, each with a different focal length to adjust for working distance. In the preferred embodiments, the eyepiece includes a singlet and a doublet lens to minimize eyestrain, and the objective lens includes a doublet and singlet field lens operative to increase depth of field and field of view. A practical implementation includes a pair of the telescopes, one for each eye of a user. Such a configuration may take the form of loupes mounted relative to eyeglass frames for surgical, medical or dental viewing applications.