Patent Publication Number: US-2007121186-A1

Title: Hologram read system

Description:
BACKGROUND OF THE INVENTION  
      The present invention relates generally to a hologram read system, and more particularly to a read system for a hologram in which authentication information hard to view in a normal viewing state is recorded.  
      Patent Publication 1 has come up with a hologram with improved forgery prevention effects, in which authentication information is recorded in such a way as to be hard to view in a normal viewing state. According to that hologram with the authentication information recorded, a minute object that is the authentication information is located behind a block object of an easily visible size, so that when the hologram is viewed in a given viewing direction, the authentication information is kept out of sight in the presence of the block object, but it is visible in another viewing direction. Accordingly, the presence of the authentication information is hardly noticeable, and even when the hologram is viewed on a magnified scale by magnifying and viewing means such as a loupe, the presence of the authentication information is hardly noticeable in a given direction that is a normal viewing direction. Thus, whether the authentication information is concealed or not is unlikely to be noticeable, making sure improved forgery prevention effects. Patent Publication 1 has also come up with an authentication information check system wherein a hologram and a camera adapted to magnify and view the authentication information recorded in the hologram are fixedly located, and a lighting device for directing reconstructing illumination light to the hologram is located in a relatively movable way, so that the authentication information can be checked up.  
      On the other hand, Japanese Patent Application No. 2005-7126 filed by Applicant discloses a fluorescent read system for an information recorded medium using a material capable of emitting visible fluorescence.  
      Patent Publication 1  
      JP(A) 2003-228270  
      As regards the authentication information check system shown in Patent Publication 1, however, there is nothing specific disclosed about the arrangement, moving mechanism, etc. of the lighting device.  
     SUMMARY OF THE INVENTION  
      In view of such situations with the prior art as described above, it is an object of the invention to provide a read system for a hologram wherein a minute object for authentication information is located behind a block object so that the minute object can be viewed from a specific direction alone.  
      According to the invention, the above object is achievable by the provision of a hologram read system adapted to view a minute object from a hologram wherein the minute object located behind a block object is recorded such that the minute object is blocked off by the block object and invisible upon viewing in a given direction, but visible from a direction different from said given direction, characterized by comprising a light block housing open at an upper end and a lower end, wherein a lighting substrate with a viewing window provided in a center is located within said light block housing at a given distance from, and substantially parallel with, said lower end, a magnifying lens adapted to magnify and view a hologram image reconstructed from said hologram through said viewing window and located facing an opening at said lower end is attached over an opening at said upper end or a camera capable of magnifying and viewing said reconstructed hologram image is detachably attached there-over, and an array of point light sources adapted to emit visible light is located on a lower surface of said lighting substrate except for said viewing window, so that any point light source in said array of point light sources can be selectively put on.  
      The invention also provides a hologram read system adapted to view a minute object from a hologram wherein the minute object located behind a block object is recorded such that the minute object is blocked off by the block object and invisible upon viewing in a given direction, but visible from a direction different from said given direction, characterized by comprising a light block housing open at an upper end and a lower end, wherein a lighting substrate with a viewing window provided in a center is located within said light block housing at a given distance from, and substantially parallel with, said lower end, a magnifying lens adapted to magnify and view a hologram image reconstructed from said hologram through said viewing window and located facing an opening at said lower end is attached over an opening at said upper end or a camera capable of magnifying and viewing said reconstructed hologram image is detachably attached there-over, and a single or multiple point light sources adapted to emit visible light are located on a lower surface of said lighting substrate except for said viewing window in such a way as to be movable said lower surface.  
      In the first hologram read system, said array of point light sources could comprise one linear array that extends in a direction tangent to the periphery of said viewing window, two linear arrays that extend in a direction tangent to the periphery of said viewing window, one or two or more linear arrays that extend in a direction tangent to the periphery of said viewing window and one or two or more linear arrays that extend in a diametrical direction of said viewing window, a circular array located around said viewing window, or a rectangular array located around said viewing window.  
      In the hologram read system of the invention, said point light sources could each be made up of, for instance, a white light emitting diode.  
      Said light block housing could have a substantially circular or rectangular section parallel with the lower end.  
      Preferably at a given position of the outer surface of said light block housing, there is an alignment mark located.  
      In one preferable embodiment, an infrared light source adapted to visualize information that is invisible under visible light but visualized by excitation with infrared light, or an ultraviolet light source adapted to visualize information that is invisible under visible light but visualized by excitation with ultraviolet light is located below said lighting substrate except for said viewing window.  
      According to the hologram read system as recited above, a hologram wherein a minute object is recorded, said minute object located behind a block object and taking an authentication information role, is illuminated with light in such a way as to make the minute object visible. While ambient light is blocked off by the light block housing, a magnifying lens or camera is used to magnify and view a hologram image for authentication information upon reconstruction by illuminating light. It is thus possible to view the authentication information in a visual, stable yet easy way.  
      Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.  
      The invention accordingly comprises the features of construction, combinations of elements, and arrangement of parts which will be exemplified in construction hereinafter set forth, and the scope of the invention will be indicated in the claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is illustrative of how one exemplary hologram with authentication information recorded in it works so as to give an account of the principles of the hologram read system according to the invention.  
       FIG. 2  is an exterior view of the hologram read system.  
       FIG. 3  is illustrative in vertical section of the hologram read system.  
       FIG. 4  is illustrative of only a lighting substrate taken out of the hologram read system, as viewed from its lower end side.  
       FIG. 5  is illustrative of how a hologram works, which hologram has a plurality of sets each comprising a block object and a minute object recorded in it.  
       FIG. 6  is illustrative of a point light source array located on the lighting substrate of the hologram read system adapted to read the hologram of  FIG. 5 .  
       FIG. 7  is illustrative of a point light source array located on the lighting substrate of the hologram read system adapted to read a reflection type volume hologram.  
       FIG. 8  is illustrative of another example of the point light source array located on the lighting substrate of the hologram read system.  
       FIG. 9  is illustrative of yet another example of the point light source array located on the lighting substrate of the hologram read system.  
       FIG. 10  is illustrative of the direction of movement of point light sources of the hologram read system adapted to read authentication information by the mechanical movement of point light sources along the lower surface of the lighting substrate.  
       FIG. 11  is a circuit diagram illustrative of one exemplary arrangement for successively putting on point light sources along the array.  
       FIG. 12  is illustrative of one exemplary mechanism for the mechanical movement of point light sources.  
       FIG. 13  is a sectional view of the hologram read system, and a perspective view of the lighting substrate for the purpose of illustrating a modification to the hologram read system of the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      The principles and examples of the hologram read system according to the invention will now be explained.  
      First of all, a hologram with authentication information recorded in it, such as the one proposed in Patent Publication 1, will briefly be explained, and the principles of the hologram read system of the invention will then be explained.  FIG. 1  is illustrative of the action of one exemplary hologram with authentication information recorded in it, as set forth typically in Patent Publication 1.  FIG. 1 ( a ) is a view as viewed from above, and  FIG. 1 ( b ) is a view as viewed from the right side. As reconstruction illuminating light  1  is incident on a hologram  10  from the front ( FIG. 1 ( a ) ) as viewed horizontally, and from above at an angle θ with respect to a normal as viewed vertically, it permits diffracted light  2  from the hologram  10  to be diffracted about the frontal direction, so that a block object  12  of an easily visible size is reconstructed in front of the hologram  10 , and a minute object  11  that is authentication information is reconstructed in the rear of the hologram  10 . Because of the fact that the minute object  11  is positioned behind the block object  12 , however, the minute object  11  is blocked off by the block object  12 ; it is not visible to the eye E of a viewer positioned in the frontal direction. As the viewer moves the eye E in either one of the right and left directions, the minute object  11  comes from behind the block object  12 , and so the viewer can view it.  
      Instead, as the direction of incidence of the reconstructing illumination light  1  is fixed in the vertical direction and its angle φ to a normal is changed in the horizontal direction, as shown in  FIG. 1 ( a ), the direction of diffraction of the diffracted light  2 , too, changes by about the angle φ in the horizontally opposite direction, so that there is a displacement in the positions where the minute object  11  and block object  12  are reconstructed. The block object  12  positioned in front of (before) the hologram  10  moves in the direction opposite to the direction of movement of the reconstructing illumination light  1 , and the minute object  11  positioned in the rear of (behind) the hologram  10  moves in the same direction as the direction of movement of the reconstructing illumination light  1 . As a result, there is a change in the horizontally relative positions of the block object  12  and minute object  11 , so that the minute object  11  is not blocked off by the block object  12 , and so becomes visible to the viewer&#39;s eye E positioned in the frontal direction of the hologram  10 .  
      The hologram  10  is prepared in the form of a reflection type relief hologram with a reflective layer provided on its relief or back surface, or a reflection type volume hologram. However, the reflection type relief hologram is constructed in the form of a rainbow hologram that can be reconstructed with white light or incoherent light. When the hologram  10  is constructed as the reflection type volume hologram, information about the relative positions of the block object  12  and minute object  11  is recorded in it in not only the horizontal direction but also the vertical direction, so that even when the reconstructing illumination light  1  is vertically moved, the minute object  11  is again not blocked off by the block object  12 , and so becomes visible to the viewer&#39;s eye E positioned in the frontal direction. When the hologram  10  is constructed as the rainbow hologram, however, three-dimensional information is recorded in it in the horizontal direction alone; when the reconstructing illumination light  1  goes up or down, the minute object  11  remains out of sight.  
      Now, some embodiments of the hologram read system according to the invention used to embody such principles are explained.  FIG. 2  is a schematic exterior view of the hologram read system, and  FIG. 3  is illustrative in vertical section of the hologram read system. In a hologram read system  20  of the invention, a main component  21  of the hologram read system is connected with a control device  26  by way of a connecting cord  27 , as shown in the exterior view of  FIG. 2 . The main component  21  comprises a cylindrical form of light block housing  22  open at its upper end  22   u  and lower end  22   d . Within the housing  22 , a substrate  23  for lighting purposes (hereinafter called the lighting substrate) with a center viewing window  24  is mounted at a given distance from, and parallel with, the lower end  22   d , and a magnifying lens  25  capable of magnifying and viewing a reconstructed hologram image is mounted over an opening at the upper end  22   u . The outside of the light block housing  22  could be in a cylindrical, truncated conical, polyhedral cylindrical or other like configuration. At a given position on the outer surface of the light block housing  22 , there is an alignment mark  28  provided, which facilitates alignment of the direction of the hologram read system with the hologram  10 . And then, to enable a hologram image reconstructed from the hologram  10  to be magnified and viewed with such a hologram read system  20 , an information recorded medium having the hologram  10 , wherein such authentication information as described above is recorded on the surface of, for instance, a substrate  31 , is brought in contact with the opening at the lower end  22   d  of the light block housing  22  while the hologram  10  is positioned within the opening at the lower end  22   d.    
      The illumination light source located on the lighting substrate  23  is now explained.  FIG. 4  is illustrative of only the lighting substrate  23  removed out of the housing  22 , as viewed from the lower end  22   d  side. The outside shape of the lighting substrate  23  is in conformity with the inside shape of the light block housing  22 . In the embodiment here, however, it is illustrated in a rectangular form for brevity. In the middle of the lighting substrate  23 , there is the viewing window  24  provided, and a linear point light source array  40  comprising a plurality of point light sources  29   1 ,  29   2 , . . . ,  29   n  such as white LEDs is located near the upper edge of that viewing window  24 . The lighting substrate  23  is fitted in the light block housing  22  such that when the information-recorded medium  30  is viewed with the alignment mark  28  in alignment with the upper direction of the hologram  10 , the point light source array  40  is oriented in alignment with the left-and-right transverse direction. The distance of the point light source array  40  from the center of the viewing window  24  is determined such that when the center point light source  29   c , in the point light source array  40  is put on, the minute object  11  and block object  12  are reconstructed at positions indicated by solid lines in  FIG. 1 ; that is, light from the point light source  29   c  becomes the reconstructing illumination light  1  that falls from above at the angle θ to the normal to the hologram  10 .  
      As the point light source array  40  comprising such point light sources  29   1 ,  29   2 , . . . ,  29   n  is located in the transverse direction and the point light sources  29   1 ,  29   2 , . . . ,  29   n  in the array are successively put on from right to left or left to right or the point light source near the left or right end of the point light source array  40  is selectively put on, it permits the minute object  11  that is the authentication information hidden off by the block object  12  to be magnified through the magnifying lens  25  and read from the front.  
      In some cases, a plurality of sets of block object  12  and minute object  11  to be reconstructed with a plurality of reconstructing illumination light beams having different angles of incidence are recorded in the hologram  10 , as shown in  FIG. 5 .  FIG. 5 ( a ) is a view of the hologram  10  as viewed from above;  FIG. 5 ( b ) is a view of a hologram portion reconstructed with one reconstructing illumination light  1   1  as viewed from the right side; and  FIG. 5 ( c ) is a view of a hologram portion reconstructed with another reconstructing illumination light  1   2  as viewed from the right side. As the one reconstructing illumination light  1   1  is incident from above on the hologram  10  at an angle θ 1  with respect to the normal, it permits diffracted light  2   1  from the hologram  10  to be diffracted about the frontal direction, so that a block object  12   1 , is reconstructed in front of the hologram  10 , and a minute object  11   1  is reconstructed in the rear of the hologram  10  while the minute object  11   1 , is positioned behind the block object  12   1 . As the another reconstructing illumination light  1   2  is incident from above on the hologram  10  at an angle θ 2  to the normal, said angle θ 2  different from the above angle θ 1 , it permits diffracted light  2   2  from the hologram to be diffracted about the frontal direction, so that another block object  12   2  is reconstructed in front of the hologram  10  and another minute object  11   2  is reconstructed in the rear of the hologram  10  while the minute object  11   2  is positioned behind the block object  12   2 .  
      In order to enables the minute objects  11   1 ,  11   2  that are the authentication information for such a hologram  10  to be viewed from the front, two rows of parallel point light source arrays  40   1 ,  40   2  are located near the upper edge of the viewing window  24  in the lighting substrate  23 , as shown in  FIG. 6 . The point light source arrays  40   1 ,  40   2  are oriented in the same left-and-right transverse direction as is the case with the point light source array  40  of  FIG. 4 . The distance of one point light source array  40   1 , from the center of the viewing window  24  is determined such that when the point light source at the center of that array is put on, the minute object  11   1  and block object  12   1 , in the layout of  FIG. 5 ( b ) are reconstructed, and the distance of another point light source array  40   2  from the center of the viewing window  24  is determined such that when the point light source at the center of that array is put on, the minute object  11   2  and block object  12   2  in the layout of  FIG. 5 ( c ) are reconstructed.  
      As either one of such point light source arrays  40   1 ,  40   2  is successively put on from right to left or left to right or the point light source near the left or right end of either one of the point light source arrays  40   1 ,  40   2  is selectively put on, it permits the minute object  11   1 , or  11   2  that is the authentication information hidden off by the block object  12   1 , or  12   2  to be magnified through the magnifying lens  25  and read from the front. Alternatively, as the point light sources in both the point light source arrays  40   1 ,  40   2  are successively put on from right to left or left to right or the point light sources near the left or right ends of both the point light source arrays  40   1 ,  40   2  are selectively put on, it permits the minute objects  11   1  and  11   2  that are the authentication information hidden off by the block objects  12   1 , and  12   2  to be simultaneously magnified through the magnifying lens  25  and read from the front. It is noted that when the point light sources in the point light source array  40   1 , and the point light sources in the point light source array  40   2  are put on at the same time, reconstructed images are often viewed as they overlap each other. In this case where the authentication information is hardly to view, it is preferable to selectively switch only one point light source array on.  
      When the hologram  10  is the rainbow hologram as described above, there is the three-dimensional information recorded in it in the horizontal direction alone. In order to make it possible for the viewer to view the minute object  11 ,  11   1 ,  11   2  that is the authentication information from the front, it is only needed to extend the point light source array  40 ,  40   1 ,  40   2  on the lighting substrate  23  in the horizontal direction of the hologram with the three-dimensional information recorded in it, as shown in  FIGS. 4 and 6 . However, when the hologram  10  is constructed as the reflection type volume hologram, it is possible to view the minute object  11 ,  11   1 ,  11   2  from the front even upon vertical movement of the reconstructing illumination light  1 , because the three-dimensional information is recorded in it in not only the horizontal direction but also the vertical direction. To this end, for instance, yet another point light source array  40   3  is located on the lighting substrate  23 , which extends in a direction orthogonal to the point light source arrays  40   1 ,  40   2 . As the point light source array  40   3  is put on successively from the viewing window  24  side to the outside or the point light source array near the outer end of the point light source  40   3  is selectively put on, it permits the minute objects  11 ,  11   1 ,  11   2  that is the authentication information hidden off by the block objects  12 ,  12   1 ,  12   2  to be magnified through the magnifying lens  25  and viewed from the front. It is noted that point light source arrays  40   1 ,  40   2  in  FIG. 7  are provided to read two minute objects  11   1 ,  11   2  selectively or simultaneously as is the case with the  FIG. 6 .  
      As described previously, at the given position of the outer surface of the light block housing  22 , there is the alignment mark  24  provided so as to facilitate alignment of the reader system with the hologram  10 . Instead for or in addition to such an alignment mark, one or multiple rows of point light source arrays  40   4 ,  40   5  may be located on the lighting substrate  23  around and coaxial with the viewing window  24 , as shown in  FIG. 8 . In this case, there is an improvement in the degree of flexibility in the orientation of the light block housing  22  set with respect to the hologram  10 . And then, the outside shape of the light block housing  22  is preferably configured into a square in section in conformity with the orientation of the sides of the square point light source arrays  40   4 ,  40   5 , because alignment of the hologram  10  with the light block housing  22  is easily achievable.  
      It is also preferable that a circular array  40   6  of point light sources is located around and coaxial with the viewing window  24  as shown in  FIG. 9 , because there is no need of aligning the light block housing  22  with the hologram  10 . In this case, how the authentication information comes into sight is somewhat different from that in the case where an illuminating light source array is in a linearly arrangement; however, there is practically no problem.  
      In the foregoing embodiments, the point light source arrays  40  and  40   1 - 40   6  comprising a plurality of point light sources  29   1 ,  29   2 , . . . ,  29   n  such as white LEDs are used as the light sources for lighting the hologram  10  located below the lower surface of the lighting substrate  23 , and the point light sources  29   1 ,  29   2 , . . . ,  29   n  are successively put on along the array for optional selection and change of the lighting position. However, it is also possible to locate one LED or other point light source or a plurality of LED or other point sources corresponding to the number of point light source arrays at the lower surface of the lighting substrate  23  in such a way that their movement is controllable. In this case, if one or plural such point light sources are mechanically moved along the lower surface of the lighting substrate  23 , it is then possible to move the illuminating point light sources to a desired position to the hologram  10 , thereby allowing the minute objects  11   1 ,  11   2  that are the authentication information for the hologram to be viewed from the front.  FIG. 10  is illustrative of one exemplary direction of movement to that end. More specifically, an example of  FIG. 10 ( a ) corresponds to  FIG. 4 , wherein one LED or other point light source  29  is located at the lower surface of the lighting substrate  23  in such a way as to be movable as indicated by an arrow, and by moving that point light source  29  along a locus corresponding to the point light source array  40  of  FIG. 4 , it is possible to view the minute object  11 . An example of  FIG. 10 ( b ) corresponds to  FIG. 6 , wherein two LED or other point light sources  29   a ,  29   b  are located at the lower surface of the lighting substrate  23  in such a way as to be movable as indicated by arrows, and by moving them along loci corresponding to the point light source arrays  40   1 ,  40   2  in  FIG. 6 , respectively, it is possible to view the minute objects  11   1 ,  11   2 . It is understood that if there is one point light source  29  provided as in  FIG. 10 ( a ) and that one point light source  29  is moved along the loci corresponding to the point light source arrays  40   1 ,  40   2  in  FIG. 6 , it is then possible to selectively read two minute objects  11   1 ,  11   2 . The same as in FIGS.  10 ( a ) and  10 ( b ) could apply to the movement of one or two or more point light sources  29 ,  29   a ,  29   b  along the loci corresponding to the point light source arrays  40   1 - 40   6  in FIGS.  7  to  9 , too.  
      It is understood that the positions to which one or two or more point light sources  29 ,  29   a ,  29   b  are moved are not only on but also near the loci corresponding to the point light source arrays  40  and  40   1 - 40   6  in  FIGS. 4 and 6 - 10 , and that they are movable to an area between the adjacent loci.  
      In order to put on the point light sources  29   1 ,  29   2 , . . . ,  29   n  successively along the point light sources  40  and  40   1 - 40   6  in  FIGS. 4 and 6 - 9 , it is preferable that such a rotary switch  41  as shown in  FIG. 11  is located in the control device  26  and that rotary switch  41  is used to put on the point light sources  29   1 ,  29   2 , . . . ,  29   n  successively in this order. And of course, an electronic changeover switch could be used to the same purpose, too.  
      For the mechanism by which the point light sources  29 ,  29   a ,  29   b  in  FIG. 10  are moved, various mechanical moving mechanisms could be used. For instance, in order to move one point light source  29  on a simple linear locus, it is preferable that the point light source  29  is attached integrally to one point on a belt  44  extending between pulleys  43   1 , and  43   2 , and the movement of the belt  44  is controlled by control of rotation of a motor  45  adapted to rotate one pulley  43   2 , as shown in  FIG. 12 ( a ) In order to provide free movement of one point light source  29  along a two-dimensional plane on any desired locus, it is preferable that the point light source  29  is attached to one point on an X-Y table  46  that is controllable to any desired position by means of a motor  47   x  adapted to move it in the X direction and a motor  47   y  adapted to move it in the Y direction, as shown in  FIG. 12 ( b ).  
      To add to this, an infrared light source capable of visualizing and viewing information that remains invisible under visible light but is visualized by excitation with infrared light may be located at any desired position below the lighting substrate  23  except for the viewing window  24 , as is the case with the fluorescent reader system set forth in Japanese Patent Application No. 2005-7126. One example is now explained with reference to  FIG. 13 ( a ) that is a sectional view of the reader system and  FIG. 13 ( b ) that is a perspective view of the lighting substrate. In this example, a plurality of infrared light emitting LEDs  48  capable of emitting infrared excitation light are located inside point light source arrays  40   1 ,  40   2  comprising hologram-read white LEDs or the like located at the lower surface of the lighting substrate  23  and around the viewing window  24 . When information drawn by a fluorescent material that is visualized by infrared excitation light is located facing an opening in the lower end  22   d  of the main component  21  of the reader system for reading purposes, point light sources  40   1 ,  40   2  in the visible range are put off while the infrared light emission LED  48  is put on.  
      While the hologram read system of the invention has been described with reference to its principles and examples, it is understood that the invention is not limited thereto and many modification could be made thereto. With the hologram read system of the invention, it is possible not only to magnify and view a reconstructed image in a visual way but also to use a TV camera through which a reconstructed image is magnified and viewed. To this end, while the magnifying lens  25  remains attached to the upper end  22   u  of the light block housing  22  or after the magnifying lens  25  is taken out, it is preferable to locate the TV camera in place. Further, an ultraviolet light source capable of visualizing information that remains invisible under visible light but is visualized by excitation with ultraviolet light could be provided in place.