Abstract: A method is provided for determining the distance between two optical boundary surfaces spaced apart from each other in a first direction. A first image is ascertained wherein the plane into which the pattern acquired coincides with a first of two optical boundary surfaces or has the smallest distance to the first optical boundary surface in a first direction. A position of the first image in the first direction is determined. A second image is ascertained wherein the plane into which the pattern acquired coincides with a second of two optical boundary surfaces or has the smallest distance to the second optical boundary surface in the first direction. The position of the second image in the first direction is determined. The distance is calculated by means of determined positions of the first and second image.

Abstract: A method is provided for determining the distance between two optical boundary surfaces spaced apart from each other in a first direction. A first image is ascertained wherein the plane into which the pattern acquired coincides with a first of two optical boundary surfaces or has the smallest distance to the first optical boundary surface in a first direction. A position of the first image in the first direction is determined. A second image is ascertained wherein the plane into which the pattern acquired coincides with a second of two optical boundary surfaces or has the smallest distance to the second optical boundary surface in the first direction. The position of the second image in the first direction is determined. The distance is calculated by means of determined positions of the first and second image.

Abstract: A tube attachment for microscopes which facilitates visual microscope work particularly over extended periods and which can be used universally for different types of microscopes and, at the same time, can be produced economically using simple manufacturing techniques, it is suggested that a tube attachment is constructed as a holder which can be adjusted with respect to height and, optionally, with respect to angle and can be fastened directly to a binocular tube of a microscope. The holder includes two carriers which are displaceable axially relative to one another and which have a forehead rest and a chin support or one carrier with the forehead rest for a user, and devices are provided at the carriers for clamping the adjusting movements of the carriers.

Abstract: A microscope objective having at least four lenses or groups of lenses and which can be used to improve image contrast. According to the invention, a phase plate, aligned concentrically to the optical axis, can be integrated into and taken out of the air space between the first lens and the second lens, as viewed from the object side. The defined arrangement of the phase plate and the associated shift of the real pupil into the air space between the first two lenses or groups of lenses, respectively, of the microscope objective allows a microscope objective, initially designed as a bright-field variant, to be redesigned as a phase contrast variant with relative ease.

Abstract: The invention relates to a microscope objective which consists of at least four lenses or groups of lenses and can preferably be used to improve image contrast. According to the invention, a phase plate, aligned concentrically to the optical axis, can be integrated into and taken out of the air space between the first lens and the second lens, as viewed from the object side. The defined arrangement of the phase plate and the associated shift of the real pupil into the air space between the first two lenses or groups of lenses, respectively, of the microscope objective allows a microscope objective, initially designed as a bright-field variant, to be redesigned as a phase contrast variant with relative ease.

Abstract: In order to provide a tube attachment for microscopes which facilitates visual microscope work particularly over extended periods and which can be used universally for different types of microscopes and, at the same time, can be produced economically using simple manufacturing techniques, it is suggested that a tube attachment is constructed as a holder which can be adjusted with respect to height and, optionally, with respect to angle and can be fastened directly to a binocular tube of a microscope. The holder comprises two carriers which are displaceable axially relative to one another and which have a forehead rest and a chin support or one carrier with the forehead rest for a user, and devices are provided at the carriers for clamping the adjusting movements of the carriers.