JP5605538B2 - Diffraction structure display - Google Patents

Description

  The present invention relates to a diffractive structure display, and more particularly to a diffractive structure display in which black and white of a display pattern is inverted or switched depending on the rotation position of the display.

  In many cases, a diffraction grating or a hologram is applied to a card such as a deposit / save card or a credit card in order to guarantee the authenticity thereof. In addition, diffraction gratings and holograms are often applied to expensive products or cases where counterfeit products are easily available, in order to guarantee their authenticity.

  The reason why diffraction gratings and holograms are applied to articles in various fields other than the above examples is because holograms and the like have difficulty in manufacturing or copying, and in appearance they are interference colors. It is easy to catch the eye and is excellent in design, and in some cases, it has the merit that it can be destroyed when trying to peel off, and it can be made a structure that can not be diverted elsewhere Because.

As such a hologram, Patent Document 1 proposes a hologram (CGH) in which phase information of a Fourier transform image of an original image is multivalued and recorded as a depth. A hologram (CGH) in which the phase information of the Fourier transform image is multi-valued and recorded as a depth is projected and reproduced on a screen surface or the like when a laser beam is applied. As shown in FIG. 11, the hologram (CGH) is obtained by sequentially performing the following steps (1) to (7).
(1) First, an original image is formed. The original image may be an arbitrarily determined image, and may be any of letters, numbers, figures or symbols, paintings, animations, photographs, and the like.
(2) Next, a Fourier transform image of the original image is created by subjecting the original image to a Fourier transform process using the computer.
(3) Amplitude = 1.
(4) Perform inverse Fourier transform.
(5) The amplitude is set to the original amplitude (the phase is left as it is).
Thereafter, returning to (2), after repeating “Fourier transform → Fourier inverse transform”, it stops when it is determined that a Fourier transform image satisfying a predetermined condition has been obtained.
(6) After stopping, extract phase data.
(7) The phase data is multivalued to obtain depth information of a predetermined number of steps.

  Multi-leveling of phase data based on the original image can be, for example, binarization, quaternarization, octarization, or 16-value conversion.

  On the other hand, Patent Literature 2 proposes a plurality of regions having a plurality of linear convex portions or concave portions having the same direction and having a plurality of light scattering ability anisotropies having different directions. As shown in FIG. 12, in the character region 20a of the number “9” and the region 20b surrounding the number “9”, the directions of a large number of linear convex portions or concave portions arranged in parallel are orthogonal to each other. When viewed from the direction perpendicular to the direction of the convex portion or concave portion of each region, the region appears to be relatively white due to scattering of ambient light, and when viewed from the direction of the convex portion or concave portion, ambient light is present in that direction. Since it is not scattered, it looks relatively black. Therefore, in the case of FIG. 12, when viewed from the upper right to the lower left, the character region 20a appears white and the surrounding region 20b appears black. When viewed from the upper left or lower right direction orthogonal thereto, the black and white are reversed, and the character region 20a appears black and the surrounding region 20b appears white.

JP 2003-122233 A JP 2008-107472 A

  Both the hologram (CGH) of Patent Document 1 and the medium having the light scattering ability anisotropy of Patent Document 2 are used as a forgery-preventing recording body or display body. It was not always sufficient in terms of design, decoration, and visual effects on the body. On the other hand, in the case of the display body of Patent Document 2, only the display pattern is reversed in black and white depending on the viewing direction, and there is little change such as switching of the display pattern, which is not necessarily sufficient in terms of design, decoration, or visual effect. It was.

  The present invention has been made in view of such a situation in the prior art, and the purpose thereof is to invert or switch the display pattern depending on the rotation position of the display body, and has high designability, decorativeness, and visual effect. Another object is to provide a diffractive structure display body having a high anti-counterfeit effect.

  The diffractive structure display body of the present invention that achieves the above object defines two coordinate axes that pass through the center of the display surface of the display body and that are orthogonal to each other along the display surface. A first pattern region comprising a first diffractive structure that diffracts and scatters with a component in the positive direction of the first coordinate axis, and a second diffraction that diffracts and scatters with a component in the negative direction of the first coordinate axis. A second pattern region comprising a structure and a third pattern region comprising a third diffraction structure having a component in the second coordinate axis direction and diffracting and scattering are arranged in parallel. To do.

  In this case, the phase information of the Fourier transform image of the original image in which the first image is arranged at a position in the positive direction of the first coordinate axis passing through the center on the image plane is used as the phase information. It consists of a hologram recorded as a depth by multi-value quantization more than ternarization, and the second diffractive structure has a second image at a position in the negative direction of the first coordinate axis passing through the center on the image plane. The phase information of the Fourier transform image of the arranged original image can be composed of a hologram in which phase data is multivalued not less than three values and recorded as a depth.

  Alternatively, the first diffractive structure comprises a blazed diffraction grating that diffracts and scatters light incident perpendicularly to the display surface with a component in the positive direction of the first coordinate axis, and the second diffractive structure includes: It may be composed of a blazed diffraction grating that diffracts and scatters light incident perpendicularly to the display surface with a component in the negative direction of the first coordinate axis.

  In addition, the third diffractive structure uses the phase information of the Fourier transform image of the original image in which the third image is arranged in the positive or negative position of the second coordinate axis passing through the center on the image plane. A diffraction grating or a light scattering ability that scatters light incident perpendicularly to the display surface to both sides orthogonal to the second coordinate axis may be composed of a hologram that has been recorded in depth as a multivalued value. You may comprise from an anisotropic scatterer.

  The diffractive structure display of the present invention has another diffraction grating densely or separated from the periphery of the display body portion in which the first pattern region, the second pattern region, and the third pattern region are arranged in parallel. It is also possible that at least one of a display area consisting of and a display area consisting of another relief hologram is arranged.

  According to the present invention, when the display body is rotated 90 ° and 180 ° around its normal from the upright state, the patterns of the three diffractive structures appear to be reversed in black and white, and each rotation when viewed as a whole It looks as if it is switched to a different pattern depending on the position, and it has high design, decoration, and visual effects. In addition, since at least one of the diffractive structures is composed of a hologram, it is possible to reproduce the authentication information by irradiating laser light, and it has a high anti-counterfeiting effect while providing design, decoration, and visual effects. Can be achieved.

It is a figure for demonstrating the hologram which multi-values the phase information of the Fourier-transform image in the case of using a point light source as an original image, and records it as depth. It is a figure which shows one example of the hologram used for the diffraction structure display body of this invention. It is a figure which shows the other example of the hologram used for the diffraction structure display body of this invention. It is a figure which shows the other example of the hologram used for the diffraction structure display body of this invention. It is a figure for demonstrating the diffraction structure display body by this invention according to preparation order. FIG. 6 is a view similar to FIG. 5 when a diffraction grating is used instead of the hologram. It is a figure for showing arrangement of one example of a diffraction structure display object by the present invention. It is a figure which shows a mode that black and white inversion is carried out and a pattern switches when the diffraction structure display body of FIG. 7 is rotated. It is a figure which shows the arrangement | positioning for confirming the authenticity of the diffraction structure display body by this invention. It is a figure which shows the area | region which can arrange | position an image on an original image surface. It is a figure which shows the preparation procedure of the hologram which multi-valued the phase information of the Fourier-transform image of a well-known original image, and was recorded as depth. It is a figure which shows the display body which consists of a well-known area | region with several light scattering ability anisotropy, and appears to reverse black and white.

  Hereinafter, embodiments of the diffractive structure display body of the present invention will be described based on the principle description.

  FIG. 1 is a diagram for explaining a hologram (CGH) in which phase information of a Fourier transform image in a case where a point light source is used as an original image and recorded as a depth, and using a Fourier transform action of a positive lens. I will explain.

  A plane passing through the front focal point F of the positive lens L at the focal length f and orthogonal to the optical axis is defined as the original image plane, and a plane passing through the rear focal point of the positive lens L and orthogonal to the optical axis is defined as the hologram surface H. The optical axis of the positive lens L is taken in the horizontal direction, the x-axis in the horizontal direction orthogonal to the optical axis on the original image plane, the y-axis in the vertical direction, the p-axis in the horizontal direction perpendicular to the optical axis on the hologram surface H, and the vertical Take q-axis in direction. When the point light source P is located at a position away from the optical axis (origin) on the y-axis on the original image plane in the negative direction, that is, as the original image, a position deviated from the center of the original image plane in the vertical direction. Consider a Fourier transform image of an image where the point light source P is located. The spherical wave emitted from the point light source P is converted into a plane wave by the positive lens L, and enters the hologram surface H as a plane wave traveling in a linear direction passing through the center of the point light source P and the positive lens L. 1A is a plan view, and FIG. 1B is a side view. The equiphase surface S of the light beam converted into a plane wave by the positive lens L is parallel to the hologram surface H when viewed from the plan view. Then, the light enters the hologram surface and enters the hologram surface H at an angle when viewed from a side view. Therefore, the equiphase position (intersection (line) between the equiphase surface S and the hologram surface H) of the Fourier transform image of the point light source P recorded on the hologram surface H is a parallel line extending in the horizontal direction (p direction). . As the equiphase position, for example, when the position of phase π and its odd multiple is the deepest position, and the position of 2π and its integral multiple is the highest position, the distribution of the highest position is the horizontal direction on the hologram surface H ( Equally spaced parallel lines (interference fringes) extending in the (p direction). The same applies when the point light source P is displaced in the positive direction from the origin on the y-axis.

  It can be understood from this examination that if the point light source P is located in a predetermined direction (y-axis direction in the above example) from the center on the original image plane, the isophase lines (interference fringes) of the Fourier transform image are obtained. Is a straight line extending in a direction orthogonal to the direction of deviation (p-axis direction in the above example).

  Although the original image is not usually a point light source P, it can be considered as a set of point light sources P. Therefore, the original image is arranged on both sides of the original image plane so as to be shifted from the center on the original image plane across a predetermined direction. The Fourier transform image of an image is formed by superimposing a number of equiphase lines parallel to a direction orthogonal to the predetermined direction and isophase lines extending at a small angle in the direction orthogonal to the predetermined direction.

  FIGS. 2A and 2B are diagrams showing one actual example, where FIG. 2A is an original image, and FIG. 2B is a diagram showing a Fourier transform image. The original image deviates vertically from the center of the original image plane (+ y direction). The character “D” is located at the position where the Fourier transform image of the original image is distributed so that the equiphase lines (interference fringes) B are substantially directed in the horizontal direction (p direction). I understand that there is.

  In this way, the Fourier transform image of the original image in which the original image is located at a position deviating from the center of the image plane is a direction (specific direction) in which the equiphase lines (interference fringes) B are orthogonal to the predetermined. Alternatively, it extends at a small angle with respect to the orthogonal direction.

  Such a phase image recording medium (hologram (CGH)) is composed of a large number of curved convex portions or concave portions B extending in parallel in a specific direction, and can be said in the embodiment of FIG. For example, light incident from the front surface of the hologram (CGH) has a light scattering ability anisotropy that scatters in a direction orthogonal to the curved convex portion or concave portion B, that is, in the ± q direction (Patent Document 2). ).

  However, as will be described later, when recording a phase on a hologram (CGH), multi-leveling of phase data is not binarized, but more than three values, four values, eight values, 16 values. In the case of the embodiment of FIG. 2, the recorded equiphase lines (interference fringes) B are blazed, and in the case of the embodiment of FIG. The light is scattered.

  FIG. 3 is a diagram showing another example, where (a) is an original image, (b) is a diagram showing a Fourier transform image, and the original image is vertically downward (−y direction) from the center of the original image plane. The character “GENUINE” is located at a deviated position, and the Fourier transform image of the original image has an equiphase line (interference fringe) B substantially in the horizontal direction (p direction) as in the case of FIG. It can be seen that they are distributed so as to face.

  Also in this case, when phase is recorded in the hologram (CGH), the phase data is converted into multi-values by performing ternarization, quaternarization, octarization, 16-value conversion, etc. (Interference fringes) B is blazed and has a characteristic that most of the ambient light is scattered in the −q direction, which is the bias direction of the original image “GENUINE”.

  FIG. 4 is a diagram showing another example, (a) is an original image, (b) is a diagram showing a Fourier transform image, and the original image is in the horizontal left direction (+ x direction) from the center of the original image plane. The character “OK” is located at an off position, and the Fourier transform image of the original image is now distributed so that the equiphase lines (interference fringes) B are substantially directed in the vertical direction (q direction). You can see that it is.

  However, in the case of FIG. 4, the phase data is binarized when the phase is recorded on the hologram (CGH). In this way, the recorded equiphase lines (interference fringes) B are not blazed and have a characteristic that most of the ambient light scatters in the ± p direction along the bias direction of the original image “OK”.

Thus, the Fourier transform image of the original image in which the original image is located at a position deviating from the center of the image plane is a direction (specific direction) in which the equiphase lines (interference fringes) B are orthogonal to the predetermined direction. ) Or extending at a small angle with respect to the orthogonal direction.

  Such a phase image recording medium (hologram (CGH)) is composed of a large number of curved convex portions or concave portions B extending in parallel in a specific direction. In the embodiment of FIG. Light incident from the front surface of (CGH) has light scattering ability anisotropy that scatters in a direction orthogonal to the curved convex portion or concave portion B, that is, in the ± q direction (Patent Document 2). The same applies to the embodiments of FIGS.

  However, as will be described later, when recording a phase on a hologram (CGH), multi-leveling of phase data is not binarized, but more than three values, four values, eight values, 16 values. In the case of the embodiment of FIG. 2, the recorded equiphase lines (interference fringes) B are blazed, and in the case of the embodiment of FIG. In the case of the embodiment of FIG. 3, the characteristic is that most of the ambient light is scattered in the −q direction, which is the bias direction of the original image “GENUINE”. In the case of the embodiment of FIG. 4, since the phase data is binarized, most of the ambient light is not only in the bias direction of the original image “OK” but also in the opposite direction, that is, in the ± p direction. It becomes a scattering characteristic.

  As shown in FIG. 1, when the point light source P is located at a position deviating from the center of the image plane in a predetermined direction, the isophase line (interference fringe) B is perpendicular to the deviating direction as described above. If the phase data is converted into multi-values that are ternary or higher, it becomes the same as a blazed diffraction grating (blazed diffraction grating). In the case of binarization, it is the same as a simple (not blazed) diffraction grating.

  Next, three holograms (CGH) as shown in FIGS. As shown in FIGS. 5 (a) / (1), (b) / (1), (c) / (1), they are shown in FIGS. 2 (a), 3 (a), and 4 (a), respectively. Prepare an original image like this. In other words, the original image 12 in FIGS. 5A and 5A has the character “D” positioned at a position deviated vertically upward (+ y direction) from the center O of the original image plane 11. Yes, in the original image 22 of FIGS. 5B / 5A, the vertically inverted character “GENUINE” is located at a position deviated vertically downward (−y direction) from the center O of the original image plane 21. The original image 32 in FIG. 5C / (1) is the one in which the character “OK” is located at a position off the center O of the original image plane 31 in the horizontal left direction (+ x direction). is there.

  Fourier transform images 13, 23, and 33 obtained by performing Fourier transform on the original image surfaces 11, 21, and 31 in the same manner as in (1) to (6) of Patent Document 1 are shown in FIGS. 5 (a) / (2), (B) / (2) and (c) / (2) have phase data as shown, and the curve schematically shows isophase lines. FIG. 2 (b), FIG. 3 (b), and FIG. And by performing each Fourier-transform image 13,23,33 like (7) of patent document 1, FIG. 5 (a) / (3), (b) / (3), (c), respectively. In the case of FIGS. 5 (a) / (3) and (b) / (3), multi-valued holograms (CGH) 14 and 24 having three or more values are shown in FIG. In the case of 5 (c) / (3), a binarized hologram (CGH) 34 is obtained.

5 (a) / (4) and (b) / (4) are schematic sectional views taken along a straight line AA ′ parallel to the q-axis of the holograms (CGH) 14 and 24, respectively. 5 (c) / (4) are diagrams schematically showing a sectional view taken along a line CC ′ parallel to the p-axis of the hologram (CGH) 34, and FIG. The cross-sectional shape of the equiphase line B indicating the phase distribution of (CGH) 14 and 24 has a sawtooth shape in the cross section of each convex portion. Even when this hologram (CGH) 14 and 24 is used in a transmission type, When a reflective surface is used with a reflective coating, the slope of the sawtooth cross section acts as a refracting or reflecting surface, and diffracted or scattered light is directed in a specific direction in the same way as a blazed surface of a diffraction grating. The hologram shown in FIGS. 4 (a) / (3) and (4). (CGH) 14, either scatter disproportionately light incident from the front + q direction is the original image 12 side scatter light incident from the oblique direction of + q in the front direction. On the other hand, the hologram (CGH) 24 shown in FIGS. 4 (b) / (3) and (4) scatters light incident from the front side in the -q direction on the original image 22 side, or scatters in the -q oblique direction. The light incident from the side is scattered in the front direction. Further, the cross-sectional shape of the equiphase line B indicating the phase distribution of the hologram (CGH) 34 is such that the cross section of the convex portion has a rectangular wave shape, and even when this hologram (CGH) 34 is used as a transmission type, the relief surface Also, when a reflective coating is used with a reflection coating, etc., diffracted light or scattered light is concentrated on both sides orthogonal to the equiphase line B, and FIG. 5 (c) / (3), ( The hologram (CGH) 34 of 4) scatters light incident from the front in the ± p direction or scatters light incident from the ± p oblique direction in the front direction.

  Note that in the case of a point light source in which the original image 12 is located at a position deviated from the center O of the original image surface 11 in the vertical upward direction (+ y direction), the above-described Fourier transform and multi-value phase data are not required. The cross section is serrated as shown in FIGS. 6 (a) / (2) (same as FIGS. 5 (a) / (4)), and the direction of the lattice is shown in FIGS. 6 (a) / (1). Thus, in the case of the point light source, the blazed diffraction grating 14 extends in the horizontal direction (p direction), and similarly, the original image 22 is located at a position deviated from the center O of the original image plane 21 in the vertical downward direction (−y direction). Even if the Fourier transform and the phase data are not multi-valued as described above, the cross section has a sawtooth shape as shown in FIG. 6 (b) / (2) (same as FIG. 5 (b) / (4)). As shown in FIG. 6 (b) / (1), the direction of the grating becomes a blazed diffraction grating 24 extending in the horizontal direction (p direction). In the case where the point light source 32 is located at a position deviated from the center O of the original image plane 31 in the horizontal left direction (+ x direction), the cross section is as shown in FIG. 6 without performing the Fourier transform and the multi-level phase data as described above. (C) / (2) (same as FIG. 5 (c) / (4)), and the direction of the grating is vertical (as shown in FIG. 6 (c) / (1)). The diffraction grating 34 is simple (not blazed) extending in the q direction.

  Similar to the hologram (CGH) 14, such a blazed diffraction grating 14 also scatters light incident from the front side biased in the + q direction or scatters light incident from the oblique direction of + q in the front direction. . Similarly to the hologram (CGH) 24, the blazed diffraction grating 24 also scatters light incident from the front side biased in the -q direction, or scatters light incident from an oblique direction of -q in the front direction. is there. Similarly to the hologram (CGH) 34, the non-blazed diffraction grating 34 also scatters light incident from the front in the ± p direction, or scatters light incident from the ± p oblique direction in the front direction. Is.

  Therefore, for example, as shown in FIG. 7, three pattern areas arranged in parallel on the display body, an inner area 41 of the character “A”, an inner area 42 of the character “B”, and an outer area 43 of the characters “A” and “B”. And the hologram (CGH) 14 in which the phase data of FIG. 5 (a) / (3) is multi-valued into three or more values (CGH) 14 or FIG. 6 (a) / The blazed diffraction grating 14 of (1) is arranged, and the hologram (CGH) 24 in which the phase data of FIG. Alternatively, the blazed diffraction grating 24 of FIG. 6B / (1) is arranged, and the phase data of FIG. 5C / (3) is binarized in the outer region 43 of the letters “A” and “B”. Hologram (CGH) 34, or the simple (blazed) of FIG. 6 (c) / (1) B) forming the display body 1 by disposing the diffraction grating 34.

When the display 1 is observed obliquely from the front of FIG. 7 when the illumination light source is positioned obliquely upward in the state of FIG. 7, as shown in FIG. The hologram (CGH) 14 or the blazed diffraction grating 14 in the inner region 41 of FIG. 1 mainly diffracts and scatters ambient light incident from an obliquely upper side of the display body 1, so that it is relative to an observer located in front. The hologram (CGH) 24 or the blazed diffraction grating 24 in the inner region 42 of the letter “B” looks bright and is positioned in front because the ambient light incident from obliquely above the display body 1 hardly diffracts and scatters forward. It looks relatively dark to the observer, and the hologram (CGH) 34 or the diffraction grating 34 in the outer region 43 of the letters “A” and “B” has an ambient light incident from diagonally above the display body 1 forward. When Since it does not diffract or scatter, it looks relatively dark to the observer located in front, so only the inner area 41 of the letter “A” appears bright, and as shown in FIG. As for 1, only the letter “A” is observed brightly.

  From this state (FIG. 7), when the display body 1 is rotated 90 ° right about its normal line while the illumination light source is located obliquely upward, the illumination light source is located relatively obliquely to the left, This time, the hologram (CGH) 14 or blazed diffraction grating 14 in the inner region 41 of the letter “A” and the hologram (CGH) 24 or blazed diffraction grating 24 in the inner region 42 of the letter “B” are almost forward. Since it is not diffracted or scattered, it looks relatively dark to the observer located in front, and diffracts and scatters forward from the hologram (CGH) 34 or diffraction grating 34 in the outer region 43 of the letters “A” and “B”. Therefore, in the display 1, the characters “A” and “B” are relatively dark, and the outer area 43 of the characters “A” and “B” is relatively bright, as shown in FIG. In addition, the display 1 is a sentence "A" and "B" are observed as dark characters.

  Similarly, when the display body 1 is rotated 90 ° to the left about the normal line while the illumination light source is located obliquely upward from the state of FIG. 7, as shown in FIG. “A” and “B” are observed as dark characters. The difference between FIGS. 8B and 8C is only that the directions of the characters “A” and “B” are opposite.

  From the state of FIG. 8 (a) (FIG. 7), the display body 1 is rotated 180 ° to the right or left about the normal line, or is further rotated 90 ° to the right from the state of FIG. 8 (b), or When the light source is further rotated by 90 ° to the left from the state of FIG. 8C, the illumination light source is positioned relatively obliquely downward, and the hologram (CGH) 14 or blazed diffraction of the inner region 41 of the letter “A”. The grating 14 hardly diffracts and scatters in the forward direction, and is now diffracted and scattered forward from the hologram (CGH) 24 or the blazed diffraction grating 24 in the inner region 42 of the letter “B”. From the hologram (CGH) 34 or the diffraction grating 34 of the outer area 43 of “A” and “B” hardly diffracts and scatters forward, so only the inner area 42 of the letter “B” looks bright. As shown in FIG. 8 (d), the display 1 is observed brightly only letter "B".

  Therefore, when the observer observes from the front, the display body 1 of the present invention is rotated by 90 ° and 180 ° from the upright state, and the patterns of the three holograms (CGH) 14, 24, and 34 are respectively obtained. Black and white appear to be reversed, and when viewed as a whole, the pattern is switched to a different pattern at each rotational position, and the design, decoration, and visual effects are high.

  Then, the authenticity proof method will be described taking the card 10 using such a display body 1 as an example. In this case, the display 1 includes a hologram (CGH) 14 in the inner area 41 of the letter “A”, a hologram (CGH) 24 in the inner area 42 of the letter “B”, and the letters “A” and “B”. In the case where the hologram (CGH) 34 is arranged in the outer area 43, the hologram is arranged not in all of the three areas 41 to 43 but only in one or two areas, and diffracted in the other areas. A lattice may be arranged. However, when the diffraction gratings 14, 24, and 34 are all arranged in the three regions 41 to 43, the following authenticity proof method cannot be adopted.

As shown in FIG. 9, a laser light source 51 is applied to such a diffractive structure display 1 to irradiate laser light 52, which is coherent light having a predetermined wavelength, from directly above. The beam diameter of the laser beam 52 may be smaller than the regions 41, 42, and 43 of the diffractive structure display 1, but the size of the plurality of regions 41 to 43 is preferable. By this irradiation, the hologram (CG) of the region 41
H) 14, original image “D”, “GENUINE”, and “OK” recorded as multi-value depth information information in hologram (CGH) 24 in region 42 and hologram (CGH) 34 in region 43. Is reproduced by the diffracted beams 54a, 54b and 54c. The authenticity can be confirmed by comparing the reconstructed image with a reference image prepared in advance and determining whether they are the same or different.

  Therefore, assuming a certain surface 53 that is separated from the display body 1 to some extent, for example, the recorded image “D” of the hologram (CGH) 14 in the area 53a on the right in FIG. 9 and the left 53b in FIG. 9, the recorded image “GENUINE” of the hologram (CGH) 24 can be observed, and the recorded image “OK” of the hologram (CGH) 34 can be observed in the area 53 c on the back side of FIG. Prepare an instrument having a top plate, a laser light source 51 and a fixing base (not shown) of the diffraction structure display 1 (card 10) for authenticity verification, etc., and each area of 53a to 53c on the top plate of the box If a transmissive screen is provided on the screen, it is possible to determine the reproduced image using this instrument, and confirm the authenticity of the diffraction structure display 1 for authenticity verification. However, it can be simplified. If the hologram is arranged only in one or two of the three areas 41 to 43, one or two of the original images “D”, “GENUINE”, and “OK” are reproduced. The Even in that case, authenticity can be confirmed by comparing with the reference image.

  In the description of FIGS. 2 and 3, images (characters) “D” and “GENUINE” recorded as holograms (CGH) 14 and 24 at positions deviated from the center of the image plane in the + y direction or −y direction of the y axis. However, it did not explain how much the image may spread in the direction orthogonal to the y-axis. The smaller the spread in the direction perpendicular to the y-axis, the more the phase of the equiphase line (interference fringe) B is directed in the direction perpendicular to the y-axis, and the scattering direction at the equiphase line (interference fringe) B Therefore, the black and white inversion of the region 41 of the hologram (CGH) 14 and the region 42 of the hologram (CGH) 24 can be remarkably observed, which is desirable.

  FIG. 10 shows a hatched area in which an image can be arranged when it actually deviates from the center O of the original image planes 11 and 21 in the + y direction. If an image to be recorded as a Fourier transform image is arranged in a range of ± 45 ° from the center O of the original image planes 11 and 21 with the y-axis in between, black and white inversion can be easily observed. Further, it is desirable to arrange within the range of 1/2 of the maximum value of the original image planes 11 and 21 in the + y direction from the center O. Exceeding the half of the maximum value in the + y direction from the center O is not preferable because the images (“D” and “GENUINE” in FIG. 9) reproduced from the holograms (CGH) 14 and 24 are distorted.

  The image (character) “OK” to be recorded on the original image surface 31 to be recorded as the hologram (CGH) 34 in FIG. 4 is desirably arranged in the same range as the hatched area in FIG. However, in this case, the y-axis in FIG. 10 is replaced with the x-axis.

  By the way, light from both sides orthogonal to the equiphase line (interference fringe) or grating line is scattered in the front direction, or light incident from the front direction is scattered to both sides orthogonal to the equiphase line (interference fringe) or grating line. Instead of the hologram (CGH) 34 or the diffraction grating 34, the light scattering ability anisotropy composed of a plurality of linear convex portions or concave portions with the same direction as described in Patent Document 2 having similar characteristics Alternatively, a light scattering region (light scattering ability anisotropic scatterer) having the following may be used. In the present invention, such a light scattering ability anisotropic scatterer is also included in the diffraction structure.

  Instead of the hologram (CGH) 34 or the diffraction grating 34, a hologram (CGH) or a blazed diffraction grating similar to the holograms (CGH) 14, 24 or the blazed diffraction gratings 14, 24 may be used. In that case, in the example of FIG. 7, the entire surface is observed in a dark and uniform state in the state of FIG. 8B or FIG. 8C.

  By the way, the diffractive structure display according to the present invention includes a first diffractive structure that diffracts and scatters light perpendicularly incident on the display surface as described above having a component in the positive direction of the first coordinate axis. A first pattern region, a second pattern region comprising a second diffractive structure that diffracts and scatters with a component in the negative direction of the first coordinate axis, and a second coordinate axis direction orthogonal to the first coordinate axis. Not only the display body 1 in which the third pattern region having the third diffraction structure having the component and diffracting and scattering is arranged in parallel, but also the display region having another diffraction grating and another relief hologram A card having a display body that is complex and has a higher design effect may be configured by arranging the display area composed of the above in a dense or separated manner around the display body 1.

  In the above description, diffraction and scattering are used in parallel as in “diffraction and scattering” because they are incident on a diffraction grating, hologram interference fringes, and light scattering ability anisotropic scatterer from a specific direction. The light is directed in a specific direction because it can be considered to be based on the diffraction phenomenon and to be considered based on the scattering phenomenon, and is used in parallel.

  The principle and examples of the diffractive structure display of the present invention have been described above. However, the present invention is not limited to these examples, and various modifications can be made.

  According to the present invention, when the display body is rotated 90 ° and 180 ° around its normal from the upright state, the patterns of the three diffractive structures appear to be reversed in black and white, and each rotation when viewed as a whole It looks as if it is switched to a different pattern depending on the position, and it has high design, decoration, and visual effects. In addition, since at least one of the diffractive structures is composed of a hologram, it is possible to reproduce the authentication information by irradiating laser light, and it has a high anti-counterfeiting effect while providing design, decoration, and visual effects. Can be achieved.

f: Focal length L ... Positive lens F ... Front focal point H ... Hologram plane P ... Point light source S ... Equiphase plane B ... Equiphase line (interference fringe, convex or concave)
O ... center of original image plane 10 ... card 11, 21, 31 ... original image plane 12, 22, 32 ... original image 13, 23, 33 ... Fourier transform image 14, 24 ... hologram (CGH), blazed diffraction grating 20a ... Character area 20b ... Area 34 surrounding the character area ... Hologram (CGH), non-blazed diffraction grating 41, 42 ... Character inside area 43 ... Character outside area 51 ... Laser light source 52 ... Laser light 53 ... Surface 53a ... Right zone 53b ... Left zone 53c ... Back zones 54a, 54b, 54c ... Diffraction light

Claims (6)

Two coordinate axes passing through the center of the display surface of the display body and orthogonal to each other along the display surface are defined, and light incident perpendicularly to the display surface is diffracted and scattered with a component in the positive direction of the first coordinate axis. A first pattern region comprising a first diffractive structure, a second pattern region comprising a second diffractive structure that has a component in the negative direction of the first coordinate axis and diffracts and scatters, and is perpendicular to the display surface A third pattern region comprising a third diffractive structure that diffracts and scatters light incident on the second coordinate axis having components on both sides of the positive and negative directions of the second coordinate axis. Characteristic diffraction structure display. The first diffractive structure converts the phase data of the phase information of the Fourier transform image of the original image in which the first image is arranged in the positive direction position of the first coordinate axis passing through the center on the image plane into phase data. The second image is arranged at a position in the negative direction of the first coordinate axis passing through the center on the image plane. 2. The diffractive structure display body according to claim 1, comprising a hologram in which phase information of a Fourier transform image of the original image is recorded as phase data obtained by converting the phase data into multi-values of three values or more. The first diffractive structure includes a blazed diffraction grating that diffracts and scatters light perpendicularly incident on the display surface with a component in the positive direction of the first coordinate axis, and the second diffractive structure includes the display surface. 2. A diffractive structure display according to claim 1, comprising a blazed diffraction grating which diffracts and scatters light perpendicularly incident on the light having a component in the negative direction of the first coordinate axis. The third diffractive structure binarizes the phase information of the Fourier transform image of the original image in which the third image is arranged in the positive or negative position of the second coordinate axis passing through the center on the image plane. 4. The diffractive structure display body according to claim 1, wherein the diffractive structure display body comprises a hologram recorded as a depth. The third diffractive structure comprises a diffraction grating or a light scattering ability anisotropic scatterer that scatters light incident perpendicularly to the display surface to both sides of the positive and negative directions of the second coordinate axis. The diffraction structure display body according to any one of claims 1 to 3. A display area comprising another diffraction grating densely or spaced apart around a display body portion in which the first pattern area, the second pattern area, and the third pattern area are arranged in parallel; another relief hologram 6. The diffractive structure display body according to claim 1, wherein at least one of the display regions is arranged.

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