Optical fiber illumination device and inspection apparatus

Abstract

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.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.

FIG. 1 is a perspective view of a paper instrument inspection apparatus according to a first embodiment of the present invention;

FIG. 2 is a side view schematically showing the paper instrument inspection apparatus;

FIG. 3 is a block diagram showing an entire structure of the paper instrument inspection apparatus;

FIG. 4 is a diagram showing diffraction light and reflection light of the hologram;

FIG. 5 is a diagram showing diffraction light of the hologram created with illumination of a spotlight;

FIG. 6 is a perspective view of a paper instrument inspection apparatus according to a second embodiment;

FIG. 7 is a perspective view of a paper instrument inspection apparatus according to a third embodiment;

FIG. 8 is a side view schematically showing the paper instrument inspection apparatus according to the third embodiment;

FIG. 9 is a perspective view of a hologram inspection apparatus according to a fourth embodiment;

FIG. 10 is a block diagram showing an entire structure of the hologram inspection apparatus;

FIG. 11 is a diagram showing incident light on the hologram and reflection diffraction light;

FIG. 12A is a diagram showing incident light on the hologram and reflection diffraction light, viewed from direction a in FIG. 11;

FIG. 12B is a diagram showing incident light on the hologram and reflection diffraction light, viewed from direction b in FIG. 11;

FIG. 13A is a side view of a light guide of the hologram inspection apparatus;

FIG. 13B is a plan view showing a light irradiated region of the light guide of the hologram inspection apparatus;

FIG. 14 is a diagram showing a cross section of the light guide taken along the line XIV-XIV of FIG. 13A;

FIG. 15 is a diagram showing a cross section of the light guide taken along the line XV-XV of FIG. 13A;

FIG. 16 is a plan view showing the hologram having a plurality of diffraction patterns;

FIG. 17 is a side view of a light guide of a hologram inspection apparatus according to the fifth embodiment;

FIG. 18 is a plan view of a light-emitting surface side of the light guide of the hologram inspection apparatus according to a fifth embodiment;

FIG. 19 is a timing chart indicating the control of the irradiation of the emission light; and

FIG. 20 is a diagram showing an optical fiber illumination device according to another embodiment of the present invention.

Claims

1. An inspection apparatus which inspects a medium to be inspected on which a hologram is attached, the apparatus comprising: a light source unit which irradiates illumination light onto the hologram of the 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; andan 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.

2. The inspection apparatus according to claim 1, wherein the light source unit includes a spotlight illuminator which irradiates spotlight illumination onto a region larger than size of the hologram to include the hologram.

3. The inspection apparatus according to claim 1, wherein the light source unit includes an illuminator which irradiates illumination light containing a wavelength range from a visible range to a near-infrared range.

4. The inspection apparatus according to claim 1, wherein the light source unit includes a spotlight illuminator which irradiates spotlight illumination onto a region in which the hologram is formed and a transmitting light illuminator which irradiates illumination light to transmit the medium, onto a region larger than size of the hologram to include the hologram.

5. The inspection apparatus according to claim 4, wherein the spotlight illuminator is an illuminator which irradiates illumination light of the visible wavelength range, and the transmitting light illuminator is an illuminator which irradiates illumination light of the near-infrared range.

6. 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.

7. 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.

8. The inspection apparatus according to claim 1, wherein the light source unit includes a light source, an optical fiber formed of a plurality of elemental fibers and guiding light from the light source and emitting the light from an emitting end, and a guide member which holds an emitting end portion of the optical fiber and has an emitting surface facing in parallel with the to-be-inspected surface of the medium, and the plurality of elemental fibers are arranged side by side and inclined at a predetermined angle excluding 90 degrees with respect to the emitting surface of the guide member in the emitting end portion of the optical fiber, and emitting ends of the plurality of elemental fibers are set to meet the emitting surface of the guide member.

9. The inspection apparatus according to claim 1, wherein the light source unit includes a light source, a plurality of optical fibers each formed of a plurality of elemental fibers and guiding light from the light source and emitting the light from an emitting end, and a guide member which holds emitting end portions of the plurality of optical fibers and has an emitting surface facing in parallel with the to-be-inspected surface of the medium, and the plurality of elemental fibers are arranged side by side and inclined at predetermined angles respectively excluding 90 degrees with respect to the emitting surface of the guide member in the emitting side end portion of each of the optical fibers, and emitting ends of the plurality of elemental fibers are set to meet the emitting surface of the guide member.

10. The inspection apparatus according to claim 9, wherein the emitting ends of the plurality of elemental fibers of the optical fiber are arranged side by side in line in the emitting surface.

11. The inspection apparatus according to claim 9, further comprising irradiation control means for allowing irradiation of light only from those optical fibers set at a desired angle, of the plurality of optical fibers.

12. The inspection apparatus according to claim 11, wherein the irradiation control means includes a shutter mechanism which opens/closes the emitting end of each of the plurality of optical fibers.

13. The inspection apparatus according to claim 9, wherein the light source includes a plurality of independent light sources respectively connected to the plurality of optical fibers, and the irradiation control means includes a control section which switches ON/OFF the plurality of light sources.

14. An optical fiber illumination apparatus which irradiates a surface to be inspected, comprising: a light source;an optical fiber including a plurality of elemental fibers, which guides light from the light source and emits the light from an emitting end; anda guide member which supports an emitting end portion of the optical fiber and has an emitting surface facing in parallel with the surface to be inspected,the plurality of elemental fibers being arranged side by side and inclined at a predetermined angle excluding 90 degrees with respect to the emitting surface of the guide member in the emitting end portion of the optical fiber, and emitting ends of the plurality of elemental fibers being set to meet the emitting surface of the guide member.

15. An optical fiber illumination apparatus which irradiates a surface to be inspected, comprising: a light source;a plurality of optical fibers each formed of a plurality of elemental fibers, which guide light from the light source and emit the light from emitting ends, anda guide member which holds emitting end portions of the plurality of optical fibers and has an emitting surface facing in parallel with the to-be-inspected surface,the plurality of elemental fibers being arranged side by side and inclined at a predetermined angle excluding 90 degrees with respect to the emitting surface of the guide member in the emitting end portion of each of the optical fibers, the inclined angles of the optical fibers being different from each other, and emitting ends of the plurality of elemental fibers being set to meet the emitting surface of the guide member.

16. The optical fiber illumination apparatus according to claim 15, wherein the emitting ends of the plurality of elemental fibers of the optical fiber are arranged side by side in line in the emitting surface.

17. The optical fiber illumination apparatus according to claim 15, further comprising irradiation control means for allowing irradiation of light only from those optical fibers set at a desired angle, of the plurality of optical fibers.

18. The optical fiber illumination apparatus according to claim 17, wherein the irradiation control means includes a shutter mechanism which opens/closes the emitting end of each of the plurality of optical fibers.

19. The optical fiber illumination apparatus according to claim 17, wherein the light source includes a plurality of independent light sources respectively connected to the plurality of optical fibers, and the irradiation control means includes a control section which switches ON/OFF the plurality of light sources.

20. An inspection apparatus which inspects a hologram including a diffraction pattern which diffracts reflection light of incident light made at a specific incident angle in a certain direction, the apparatus comprising: a holder mechanism which holds a medium to which the hologram is attached;an optical fiber illumination apparatus which irradiates light on the hologram;an image pickup section which picks up an image of diffraction light from the hologram;an image processing section which processes the image picked up by the image pick up section; andan identification processing section which identifies deficiency, fatigue and authenticity of the hologram from the processed image;the optical fiber illumination apparatus including: a light source; an optical fiber formed of a plurality of elemental fibers, which guide light from the light source and emit the light from emitting ends, and a guide member which holds emitting end portions of the elemental fibers and has an emitting surface facing in parallel with the medium, the plurality of elemental fibers being arranged side by side and inclined at a predetermined angle excluding 90 degrees with respect to the emitting surface of the guide member in the emitting end portion of the optical fiber, and emitting ends of the plurality of elemental fibers being set to meet the emitting surface of the guide member.

21. The inspection apparatus according to claim 20, wherein the image pickup section includes a line image sensor.