Abstract: The invention is directed to a device for generating an optical collimating beam having a defined angle with respect to a base when mounted thereon even in the presence of extreme mechanical and thermal loads. The device can be used for testing long guideways on machine tools, for example. The device includes a housing wherein a collimator is mounted in a form-tight manner for imaging a collimating mark out to infinity. The collimator is configured as a mirror system and includes several components connected tightly to each other. These components define a chamber filled with a gaseous medium and through which the imaging beam path extends. The collimator functions without problems even in the presence of extreme mechanical and thermal loads and, most importantly, is insensitive to temperature changes.

Abstract: The invention is directed to a device for generating an optical collimating beam. The device is so configured that it withstands extreme mechanical and thermal stresses and that the collimating beam is always at a precisely defined angle with respect to the base that supports the device. The device includes a single-lens objective having a first optical surface upon which the collimating mark is arranged which the objective images at infinity. The objective is made of transparent material having a linear temperature coefficient of expansion of less than 10.sup.-6 K.sup.-1. The objective is held in a metal housing in a form-tight manner and a thin layer surrounding the peripheral surface of the lens is disposed between the objective and the metal housing. This layer is made of an elastic material which is permanently elastic. The housing is connected form-tight and lock-tight with the base. The attachment is protected against shock and vibrational stress.