Optical scanning device

#The invention relates to an optical scanning device comprising a light transmitter and a light receiver which are arranged in spatial proximity to one another and which each comprise a deflecting device with which a scanning light beam emitted by a transmitter unit is directable along a transmission path onto an object to be scanned and, after reflection at said object, along a reception path onto a receiving unit.

#Such scanning devices serve, for example, as range finders which work according to the principle of light transit time and in which the transmitting unit comprises a laser device.

#These systems are characterized by high sensitivity of the light receiver which can be in the range of some nW so that a reliable detection of objects with low degrees of reflection is ensured. The transmitting power of the light transmitter is, in contrast, a plurality of orders of magnitude higher and can be, for example, in the range of some mW to some W.

#The invention is described in the following by way of example with reference to the drawing.

#FIG. 1 shows an optical scanning device in accordance with an embodiment of the invention in a sectioned view;

#FIG. 2a shows the scanning device of FIG. 1 in a sectioned view, turned 90° with respect to FIG. 1, in the region of a light transmitter; and

#The optical scanning device in accordance with FIG. 1 comprises a light transmitter 12 and a light receiver 14 which are each arranged in close proximity to one another in a respective chamber 42, 44 of a common housing 26. The transmitting chamber 42 and the receiving chamber 44 are separated from one another by a light-tight partition wall 36. A light permeable window 52, 54, made for example of glass, is provided for each of the chambers 42, 44 in the housing wall.

#Reference is also made to the views of FIGS. 2a and 2b, each turned through 90° with respect to FIG. 1, to describe the light transmitter 12 and the light receiver 14.

#The light transmitter 12 comprises a transmitting unit 32 with a laser apparatus and a deflecting device 22 in the form of a drivable mirror wheel rotatable around an axis 38. Light emitted from the laser of the transmitting unit 32 is incident to one of the planar mirror surfaces 22a of the mirror wheel 22, which rotates in operation, and is reflected at a certain angle, in this embodiment at an angle in an angular range of approximately 90°, through the window 52 as a scanning light beam 16 in dependence on the instantaneous angular position of said mirror wheel 22. The totality of all light propagation paths for scanning light beams 16 coming from the transmitting unit 32 forms one transmission path up to the reflection at an object 18 (cf. FIG. 1) whose distance is to be measured.