Optical fiber illumination device and inspection apparatus
An inspection apparatus includes a light source unit which irradiates illumination light onto a hologram of a medium from a predetermined direction at which diffraction light from the hologram is obtained, a first light receiving member which receives the diffraction light from the hologram, a second light receiving member which receives transmitted part of illumination light irradiated onto the hologram, having passed through the medium, and an identification processing unit which identifies authenticity of the hologram from the diffraction light received by the first light receiving member and identifies a defect of the hologram from the transmitted light received by the second light receiving member.
1. An inspection apparatus which inspects a medium to be inspected on which a hologram is attached, the apparatus comprising:
a light source unit comprising a spotlight illuminator which irradiates spotlight illumination light onto the hologram of the medium from a predetermined direction at which diffraction light from the hologram is obtained, and a transmitting light illuminator which irradiates illumination light to transmit through the medium, onto a region larger than the size of the hologram to include the hologram;
a first light receiving member which receives the diffraction light from the hologram;
a second light receiving member which receives the transmitted part of illumination light irradiated onto the hologram, having passed through the medium; and
an identification processing unit which identifies authenticity of the hologram from the diffraction light received by the first light receiving member and identifies a defect of the hologram from the transmitted light received by the second light receiving member,
wherein the transmitting light illuminator is configured to irradiate illumination light onto the medium in a direction inclined to the medium, and the second light receiving member is arranged to receive the transmitted illumination light in a direction perpendicular to the medium.
2. The inspection apparatus according to claim 1 , wherein the spotlight illuminator is configured to irradiate spotlight illumination light having a spot diameter of the same size as that of the hologram.
3. The inspection apparatus according to claim 1 , wherein the spotlight illuminator is an illuminator which irradiates illumination light of a visible wavelength range, and the transmitting light illuminator is an illuminator which irradiates illumination light of the near-infrared range.
4. The inspection apparatus according to claim 1 , further comprising: a holder mechanism which holds the medium to be inspected while applying a tension to the medium, wherein the light source unit and the first light receiving member are provided on one side of the held medium and the second light receiving member is provided on another side of the medium.
5. The inspection apparatus according to claim 1 , further comprising: a conveying mechanism which conveys the medium in a direction parallel to a surface thereof to be inspected while applying a tension on the medium in a plane direction of the medium, wherein the inspection apparatus identifies authenticity and defect of the hologram while conveying the medium by the conveying mechanism.
6. The inspection apparatus according to claim 1 , wherein the hologram includes a metal layer attached on the medium and a diffraction pattern on the metal layer, and the identification processing unit is configured to identify a damage of the metal layer of the hologram from the transmitted light received by the second light receiving member.