Patent ID: 7209046

Claim:
A method for the detection and signaling of dew films in optical smoke detector by means of an optical assembly in a detector casing, the optical assembly including at least one optical transmitter element and at least one optical receiver element, said optical receiver element emitting a reception signal that is representative of the incident amount of light, the method including the steps of: comparing the reception signal to a setpoint using an electronic evaluation device; generating an alarm signal when the reception signal reaches a predetermined threshold value wherein said electronic evaluation device compares the reception signal to a setpoint and an alarm signal is generated when the reception signal reaches a predetermined threshold value, the temperature being measured on at least one of on and in the detector casing; correlating the temporal characteristic of the temperature with the temporal characteristic of the reception signal of the optical receiver element; and generating a dew film signal when the rise in the reception signal is correlated to a rise in temperature.