How described in the previous paragraphs, the optical path in X-RAY imaging runs from the light emitting phosphor of the image intensifier tube to the recording surface of a camera. In both cases the optical systems will be optimised for the glass layer mounted on a tube intensifier and on the TV-Camera.
Normally the thickness of the cover glass of the Vidicon camera is 2.3 mm and 1 mm for a CCD Camera.
The same optical system is designed to accept this glass thickness variation. The thickness of the cover glass mounted on the intensifier tube is different, in fact it can change from 3.5 mm to 16 mm : for this reason is necessary to design the appropriate optical system with a compensation for each particular cover glass.
In the following paragraphs the optical systems as collimating lens, TV-Camera lens and optical relay will be presented and described; in the table 3.1 the list of the Optical Relay is reported, in the table 3.2 and 3.3 the list of the collimating lens and in the "X-RAY Application Table" all the possibilities to couple the lens with the X-Ray tube and TC-Camera are listed.
Any description will be performed about the cine/spot camera lens because, for the moment, OPTEC doesn't produce these particular optical systems. The standard solution is composed of two lenses, a collimating lens and a camera lens, combined to a so called tandem combination.
The focal plane of the collimating lens coincides optically with the object plane ( this plane is the output window of the intensifier tube ). In this manner the object plane is projected to infinity plane, normally the focal length of the collimating lens is chosen such as to make the maximum field angle 8 degrees.
In front of the collimating lens the TV-Camera lens is mounted in order to transfer the image from the collimator to the focal plane of the TV-Camera lens ( this plane is the recorder surface of the camera ).