Device and method for online detecting waviness of float glass

The invention discloses a device for online detecting waviness of float glass, comprising a light source, a expander lens, a light source box, a supporting stage and a projection whiteboard; the semiconductor laser and expander lens are arranged in the light source box separately, the expander lens is arranged in front of the light exit opening of the light source box, and a slit matched with theexpander lens is arranged on the light source box, the to-be-detected float glass is fixed on the bearing platform, parallel light beams are emitted from the slit, and the light beams are irradiated to the to-be-detected float glass and irradiated to the projection white board after diffraction. The device for online detecting waviness of float glass overcomes the problems that the detection speedis too slow although the detection method in the prior art is accurately, that the detection area is not comprehensive for the larger and larger glass since sampling inspection is only performed on the float glass, and that g