Abstract: A comparison-type dimension measurement system in which a laser 1 provides linearly polarized light that is directed by a polarization beam splitter 5 into a microscope system in which a specimen 13 is mounted. The reflected polarized light is rotated 90.degree. by a quarter wave plate 9 and passes through the beam splitter to a multi-element line sensor 19. The laser light is scanned by a rotatable mirror 3 over the specimen. Threshold intensities are determined on indicia of known separation on a reference specimen and used to calibrate the distance measured by the line sensor.

Abstract: An automatic focusing device for vertical focusing of a specimen 23 in which an enlarging condenser lens 11 is placed between a light source 12 and a half mirror 7 in an automatic focus detecting system so that an enlarged image 24 of the light source is presented to an objective 1 of the focusing microscope M.

Abstract: Automatic focusing apparatus in an optical drawing machine, comprising a drawing optical means having a dichroic mirror which transmits light for drawing and reflects light for detecting the focus to apply the focus detecting light to which a photosensitive material is insensitive onto the latter, an imaging lens means, and a focus detecting device for detecting whether the surfaces of the photosensitive material are located in the depth of focus of the drawing optical means.