Base board defect detecting device

In use for detecting base plate of optical disk, the disclosed detector set includes a light source, a first polarized light plate and a second polarized light plate. Being setup at one side of the first polarized light plate, the light source emits a beam of light. The second polarized light plate is setup at the other side of the first polarized light plate. Direction of polarized light of the first polarized light plate is perpendicular to direction of polarized light of the second polarized light plate. In time of carrying out test, the optical base plate is placed between the first polarized light plate and the second polarized light plate. Light beam from light source passes through the first polarized light plate, the optical base plate and the second polarized light plate in sequence. The invention can raise yield of final product of optical disk and save manufacturing cost.