Attenuating an inspection device that inspects transparent or translucent cylindrical body

1 . An inspection device that inspects a transparent or translucent cylindrical body as an inspection object, the inspection device comprising:

an illumination device that irradiates the inspection object with predetermined light;

a rotation unit that rotates the inspection object about a predetermined rotation axis;

a fiber optical plate that:

holds a plurality of optical fibers arrayed in parallel along a direction of the rotation axis, and

has a light incident surface facing the inspection object and a light emission surface opposite to the light incident surface, wherein

light rays from the inspection object enter the light incident surface, pass through the optical fibers to reach the light emission surface, and are output from a plurality of outlets of the optical fibers disposed at the light emission surface, and

the light incident surface and the light emission surface are flat surfaces orthogonal to a side face of the fiber optical plate located between the light incident surface and the light emission surface;

an imaging unit that:

comprises a plurality of sensor elements that are arranged in a row and respectively correspond to the outlets, and

takes an image of the inspection object by receiving with the sensor elements the light rays transmitted through the fiber optical plate;

a control device that determines whether a quality of the inspection object is good or poor based on the image obtained by the imaging unit; and

an oblique ray attenuation body that:

is disposed between the light emission surface and the imaging unit, and

comprises a plurality of attenuation function elements arrayed in parallel and each surrounding an optical path between each of the outlets and each of the sensor elements corresponding to each of the outlets, wherein

the attenuation function elements attenuate, out of the light rays output from the light emission surface, oblique rays that are inclined with respect to an extending direction of the attenuation function elements, and

each of the attenuation function elements is:

composed of at least one of:

a bellows cylindrical body; and

a telescopic cylindrical body including two or more cylindrical portions, and

extendible between the outlets and the sensor elements to change an absorption area that absorbs the oblique rays and regulate a degree of attenuation of the oblique rays.

2 . The inspection device according to claim 1 , further comprising:

a distance adjustment unit that comprises a holding base and a rail, and moves at least one of the inspection object and the fiber optical plate, and adjusts a distance between the inspection object and the light incident surface of the fiber optical plate.

3 . The inspection device according to claim 1 , further comprising:

a distance keeping unit that keeps constant a distance between a part of the inspection object that is an imaging object by the imaging unit and the light incident surface of the fiber optical plate by moving at least one of the inspection object and the fiber optical plate with rotation of the inspection object by the rotation unit.

4 . The inspection device according to claim 2 , further comprising:

a distance keeping unit that keeps constant a distance between a part of the inspection object that is an imaging object by the imaging unit and the light incident surface of the fiber optical plate by moving at least one of the inspection object and the fiber optical plate with rotation of the inspection object by the rotation unit.

5 . The inspection device according to claim 1 , further comprising:

a distance keeping unit that keeps constant a distance between a location of the inspection object that is an imaging object by the imaging unit and the light incident surface of the fiber optical plate by moving at least one of the inspection object and the fiber optical plate with rotation of the inspection object by the rotation unit.

6 . The inspection device according to claim 1 , further comprising:

a distance keeping unit that keeps constant a distance between a location of the inspection object that is an imaging object by the imaging unit and the light incident surface of the fiber optical plate by moving at least one of the inspection object and the fiber optical plate with rotation of the inspection object by the rotation unit.