Optical system having a focus detection device

摘要

An optical system is described, in which a light beam is projected from a projection device from the image side of the optical focusing element of the optical system with a focusing function onto an object via the optical focusing element; the light beam reflected by the object passes again through the optical focusing element and is then detected by means of a light reception device, whereby the distance to the object can be measured; on the image side of the optical focusing element a light-directing element is disposed, which makes use of total reflection in order to direct the light beam from the light projection device onto the optical focusing element and to direct the light beam from the optical focusing element onto the light reception device.