Patent ID: 7631999

Claim:
A line light irradiation device for use in product inspection comprising: multiple light emitting parts each of which is provided with an optical fiber band and a columnar lens wherein the optical fiber band comprises a light irradiating part formed by arranging light leading out end portions of multiple optical fibers in a straight line or in multiple straight lines and a binding part formed by binding light introducing end portions of the optical fibers and portions of the multiple optical fibers between the light irradiating part and the binding part are formed as a sheet form and the columnar lens is arranged to extend along a direction of the straight line in front of the light irradiating part in pairs, and that irradiate line light that converges into the straight line; and multiple light sources that introduce light into the multiple optical fibers; and a holding body that is arranged to face to an object on which the straight line light is to be irradiated, on which a monitoring bore is arranged to penetrate in order to monitor the object, the holding body holds the light emitting parts so that each optical axis of the line light irradiated from each of the light emitting parts crosses on a predetermined straight line, wherein the light emitting parts are of a same shape and predetermined lengths of the multiple optical fibers of the optical fiber band are made to be different so that the binding part is located to deviate to either one of two directions with respect to a center line of the light irradiating part and two identical optical fiber bands are mounted with their front and back sides turned upside down in the holding body so that the location of each adjacent binding part is different and the multiple light emitting parts are arranged serially along the above mentioned direction of the straight line and the multiple light sources are arranged along the above mentioned direction of the straight line on the holding body and wherein each light emitting part is arranged on the holding body so that the optical axis of the line light irradiated from each light emitting part is arranged radially viewed from the above-mentioned direction of the line.