A wet type dust collecting apparatus of a vacuum cleaner is provided. By using this device, polarization-dependent differences in the intensity and response of the light passing through the objective, which lead to a worsening of the imaging quality of the projection objective, can largely be avoided. The dovetail joint secures the rods to the endplates without the need for sealing or coating agents. In a specific embodiment, a laser dazzling device includes a plurality of green laser diodes. When using the product, it is not required to evacuate the air conditioning system.