| 摘要 |
The device has a main beam path (31,32) and one or more windows (37,39). The windows have at least two sections at or capable of being set to an angle to each other. These sections are illuminated by an additional transmitting and receiving beam path (38). In addition to the main beam path, a reference beam path with its own transmitter (33) and receiver (34) are provided. The transmitted (31) and received (32) main beams preferably each have a window with an angled section. For each window, a reference beam path may be used, where a wall with a filter for the wavelength of the reference beam between the windows. This wavelength differs from the transmitted wavelength of the main beam path. The reference beam path may be formed for an integral measurement of window pane pollution. |
