Collision avoidance system for detecting the blind spot of vehicle

A collision avoidance system detecting the blind spot of a vehicle is provided to miniaturize the system to be easily mounted on a side mirror of a vehicle by replacing an infrared light emitting diode generator with a single channel generator. A collision avoidance system detecting the blind spot of a vehicle comprises an infrared sensor unit. The infrared sensor unit sends and receives infrared ray to an obstacle within the blind spot of the vehicle and radiates sensing signals The infrared sensor unit comprises a single channel infrared ray generator(410), an optical path change part(420), a rotary reflecting part(430), and a receiving controller. The single channel infrared ray generator radiates the infrared ray by including one infrared light emitting diode(412). The optical path change part is installed at the light emitting side of the single channel infrared ray generator. The optical path change part comprises a reflection flat board(422). The rotary reflecting part is installed to be parallel to the optical path change part. The rotary reflecting part rotates with consecutively reflecting the reflected infrared ray to the blind spot of the vehicle. The receiving controller senses the incident infrared ray and determines the existing of an obstacle.