MIRROR INSPECTING DEVICE

PURPOSE:To reduce the burden of an inspector and to inspect the mirror of a plate-like plate material by forming a light source to a linear shape, and providing a photodetecting member having two pieces of linear photodetecting parts by placing an incident position of a reflected light between. CONSTITUTION:As for a light source 2, a white fluorescent lamp of 20W, etc., are used, and its length is selected suitably by a relation of width of an object 1 to be inspected and length of a photodetecting member 3. Also, in the member 3, photodetecting parts 3a, 3b are installed so as to be opposed by placing an incident position of a reflected light between, when the surface of the object 1 is completely specular. Light beams from both ends 2a, 2b of the light source 2 are reflected by two points 1ae, 1be on the object 1, and made incident on an arbitrary point 3e, therefore, data related to a state of a line between the point 1ae - the point 1be is overlapped and obtained. In the same way, a light beam from each point of the light source 2 is reflected by each point on the object 1 and made incident on each point of the member 3. If there is a defect on the surface, a halo which expands in the incident surface direction is made incident on both the photodetecting parts 3a, 3b, and made incident on plural areas of a silicon photodiode placed linearly in the direction vertical to the incident surface, therefore, a detection of a defect is executed.