Optical device for the observation of an elongated object

DETAILED DESCRIPTION Accordingly, it is an object of the invention to obtain a large resolution with an extended field.
The object is obtained by applying to the object, optionally by a transparent plate, a cylindrical lens or the like whose axis is along the large dimension of the object.
In a plane passing through the axis of the cylindrical lens, the convergence, and therefore the magnification, is insignificant while in a plane perpendicular to the axis, i.
e.
along the small dimension of the object to be observed, the lens is convergent with a magnification which increases the resolution.
However, the focal distance of this cylindrical lens (distance considered along the small dimension of the object) is small relative to the focal distance of the object for observation so that this cylindrical lens does not cause an appreciable aberration to this lens.
The focal distance of the cylindrical lens is preferably between 100 microns and 1 mm and the ratio between the focal distance of the object and that of the cylindrical lens is preferably between 10 and 100.
The elongated cylindrical lens, of practically the same dimensions as the object to the observed, can consist of a single optical fiber which, preferably, exhibits a flat surface along its length.
The flat surface is, for example, along a diametral plane.
This optical fiber, exhibiting or not a flat surface along its large dimension, can be glued to an elongated, transparent plate.
As indicated above, the cylindrical lens forms part of an optical device for observation, and optionally illumination, of the object.
To this cylindrical lens, another cylindrical lens, of more standard embodiment, can be joined, for observation, to correct the astigmatism introduced by the first cylindrical lens covering the object to be examined.
The interference introduced by the first cylindrical lens is small, the convergence of the cylindrical lens for correction is also small.