JP4064378B2 - Method and apparatus for coupling external light in waveguide hologram - Google Patents

Description

  The present invention relates to a method and apparatus for coupling external light in a waveguide hologram, and more specifically, has a function equivalent to a watermark in a banknote, a micro character, a hologram in a credit card, and the like, and further, a passport, a license, an insurance. By applying it to certificates, various membership cards, etc. that are relatively easy to counterfeit, it is possible to guarantee the legitimacy of these carriers, or certify that the product package etc. has not been opened by applying it to the product package etc. The present invention relates to a method and apparatus for coupling external light in a waveguide hologram.

2. Description of the Related Art Conventionally, bills, credit cards, passports, licenses, insurance cards, various membership cards, and the like have been used with a technique for preventing forgery by attaching items that require advanced technology for manufacturing. For example, it is a watermark of a banknote, a micro character, a hologram in a credit card, etc. (for example, refer patent document 1). However, since these examples are made when manufacturing banknotes and cards, they are applied when making the same product in large quantities, especially for products manufactured without being conscious of safety. It does not prevent counterfeiting.
In order to prevent forgery of an article by applying a sticker to an article after manufacture, and to improve safety, it is desirable that the sticker to be attached satisfies the following standards.

(1) It is extremely difficult to forge.
(2) A legitimate manufacturer can manufacture at a low cost.
(3) Easy authentication.
(4) Can be easily applied, but difficult to remove.
(5) Even if it can be peeled off, it can no longer be used once peeled off.
(6) The safety level can be changed according to the importance.
And so on.

On the other hand, a hologram information recording medium using holography has been proposed as an information recording medium that is difficult to forge and has a large storage capacity.
However, conventional hologram information recording media cannot be mass-produced if they have excellent storage capacity, and those that can be mass-produced by applying printing technology have a large storage capacity because the storage density is limited. There are various problems such as being unable to do so. Therefore, the present inventors made use of the principle of a plane hologram that is difficult to forge and that can be mass-produced. On the other hand, the plane holograms can be stacked in multiple layers and the holograms from each layer can be reproduced independently. A reproduction-only multiplex hologram card was proposed (see Patent Document 2).

FIG. 9 is a cross-sectional view showing this reproduction-only multiplex hologram card. This reproduction-only multiplex hologram card 1 is divided into: / clad 2-1 / core 3-1 / clad 2-2 / ... core 3-n-1 / The end of the periodic layer structure such as the cladding 2-n / is a reflection surface 4 of 45 °. In any / cladding / core / cladding / unit, a planar single mode waveguide is formed with respect to the wavelength of the laser beam 5 to be used.
In this read-only multiplex hologram card 1, when a core and a clad are manufactured using a normal polymer material having a refractive index of about 1.48, the core thickness needs to be 2.4 μm or less from a single mode condition. . Further, in order to suppress crosstalk between the cores, it is necessary to make the thickness of the clad sufficiently thicker than 6 μm.

In this reproduction-only multiplex hologram card 1, the laser beam 5 is condensed by the convex lens 6 so as to be focused on the 45 ° cut position of each core (core 3-5 in FIG. 3) and reflected by the reflecting surface 4. It propagates as guided light 7 in each core (core 3-5 in FIG. 3). The guided light 7 is diffracted by the scattering factor 8 while propagating in the core 3-5 and appears as diffracted light 9 outside the core 3-5, and the diffracted light 9 forms a hologram image 10.
JP-A-6-259013 JP-A-11-345419

  By the way, as the technology level of the world advances, forgery technology also advances, so if the same technology is used, the condition of standard (1) is not satisfied. For example, in the method of attaching magnetic information, forgery has already been carried out relatively easily, and forged damage has occurred in various places. Also, a normal hologram seal is not safe because the hologram manufacturing technology is not already a technology that can be monopolized by a limited organization and does not satisfy the standard (5).

  In addition, when the reproduction-only multiplex hologram card described above is used as a seal, the reference (1) and the reference (2) can be easily achieved as described later. However, in the conventional waveguide hologram, the reference after the reference (3) is used. not filled. For example, in order to obtain a diffraction image, at least light must be coupled to the waveguide, but at least a human hand is used to accurately match the focused beam to the core layer having a thickness of about 1 μm. As long as there was a problem of having to expect a very rare coincidence.

The present invention has been made in view of the above circumstances, and has functions equivalent to a watermark and micro characters on a banknote, a hologram on a credit card, and the like, and also has a passport, license, insurance card, various membership cards. By applying it to items that are relatively easy to counterfeit, it is possible to guarantee the legitimacy of these carriers, and by applying it to product packages, etc., it is proved that the product package has not been opened. As a seal that satisfies the above-mentioned criteria (1) to (6), external light that enters the planar optical waveguide from the outside is coupled to the planar optical waveguide to be guided light. When using a waveguide hologram type anti-counterfeit seal comprising a waveguide hologram having an external optical coupling hologram made of a grating, this external optical coupling hologram To provide a binding method and coupling device of the external light in the waveguide holograms that can be more easily couple the external light for.

In order to solve the above-mentioned problems, the present invention employs the following method and apparatus for coupling external light in a waveguide hologram.
In other words, the external light coupling method in the waveguide hologram of the present invention is based on a grating that uses external light incident on the planar optical waveguide from the outside to the planar optical waveguide to be guided light. A method for combining external light in a waveguide hologram having an external optical coupling hologram, wherein light emitted from a laser light source or an output end of an optical fiber is used at an input portion of the external optical coupling hologram using a lens. In addition to the plane wave, the laser light source or the emission end is vibrated in a direction perpendicular to the optical axis of the lens by using a vibrating means, thereby vibrating the incident direction of the plane wave incident on the input unit. by matching the direction of the direction of the vibration in the traveling direction of the guided light, it is attached to the planar optical waveguide the plane wave as external light And wherein the door.

The external light coupling device in the first waveguide hologram of the present invention is a grating in which external light incident on the planar optical waveguide from the outside is coupled to the planar optical waveguide to be guided light. A device for coupling external light in a waveguide hologram having an external light coupling hologram comprising: a laser light source , and a lens that converts light emitted from the laser light source into a plane wave at an input portion of the external light coupling hologram And vibration means for vibrating the incident direction of the plane wave incident on the input unit by vibrating the laser light source in a direction perpendicular to the optical axis of the lens, and changing the direction of vibration in the incident direction. By matching the traveling direction of the guided light, the planar wave is coupled as external light to the planar optical waveguide.
The external light coupling device in the second waveguide hologram of the present invention is a grating in which external light incident on the planar optical waveguide from the outside is coupled to the planar optical waveguide to be guided light. A device for coupling external light in a waveguide hologram having an external optical coupling hologram comprising: a laser light source; an optical fiber that guides light emitted from the laser light source; and an output end of the optical fiber. The incident light incident on the input portion of the plane wave by vibrating the exit end in a direction perpendicular to the optical axis of the lens. Vibration means for oscillating the plane wave, and by making the direction of vibration in the incident direction coincide with the traveling direction of the guided light, the plane wave is used as the external light. Characterized in that for coupling to the waveguide.

To further explain the present invention, the criterion (1) is satisfied by adopting the waveguide hologram technique in light of the above-described six criteria. For reproduction of the hologram, a laser is used even if it is for visible light in consideration of "seeing with eyes". However, if necessary, a light receiver such as a CCD or a CMOS detector and an image recognition technique may be used.
Here, using a visible light laser contributes to improving security because it is difficult for general users to know what information is written.

  The light source may be any visible light laser having a coherence length of several millimeters or more, and a waveguide hologram can be produced in accordance with the wavelength. More specifically, the wavelength may be set according to the level of security required. For example, the shorter the wavelength, the more difficult it becomes to manufacture a waveguide hologram, so the level of security against forgery is improved, and it is generally difficult to obtain a laser light source with a short wavelength.

However, from the viewpoint of cost-effectiveness, it is preferable to use an inexpensive red semiconductor laser that is used as a compact disk reproducing light source. Even in this case, the unevenness of the hologram must be drawn with a fine line having a thickness of 0.2 μm or less at a pitch of 0.5 μm with respect to red laser light having a wavelength of 780 nm. However, at the current technical level, such a technique for drawing a fine line can be implemented only in a limited organization. For example, a malicious third party can obtain such a technique for drawing a fine line. The possibility of doing is small.
Furthermore, since a technique for forming an optical waveguide is required, it is necessary to have a microfabrication technique and a waveguide technique at the same time. In order for such a technology to generally spread, it will still require 10 years.

By the way, when the wavelength of the laser beam is 410 nm, the projections and depressions of the hologram require an ultrafine wire processing with a pitch of 0.3 μm and 0.1 μm or less, so an electron beam drawing device or a deep UV drawing device is used to produce a master disk. Is required. These devices are already established and possessed by some research institutions, etc., but it will take a longer time to spread to the general public.
On the other hand, if it is an organization having master production and waveguide technology, it is a merit of the waveguide hologram that mass production is possible. Therefore, the above-mentioned standard (1) and standard (2) are those of the waveguide hologram itself. The characteristic is satisfied to some extent.

According to the present invention, the standard (1) it is extremely difficult to forge, (2) a legitimate manufacturer can manufacture at a low cost, and (3) it is easy to determine authenticity. (4) Can be easily applied, but difficult to remove, (5) Even if it can be removed, it cannot be used again, (6) Security depending on importance Level that can be changed, etc. can be satisfied, anti-counterfeiting, and external that is incident on the planar optical waveguide from the outside as a seal that can authenticate the legitimacy of the wearer When a waveguide hologram type anti-counterfeit seal comprising a waveguide hologram having an external optical coupling hologram comprising a grating that couples light to the planar optical waveguide to produce guided light is used , It can be more easily couple the external light to the external light coupling hologram.

Hereinafter, embodiments and reference embodiments of the present invention will be described with reference to the drawings.
[ First Reference Form ]
1A and 1B are diagrams showing a waveguide hologram type forgery prevention seal according to a first embodiment as a premise of the present invention, in which FIG. 1A is a side view, FIG. 1B is a top view, and FIG. In the figure, reference numeral 11 denotes an input portion, 12 denotes an output portion on which a hologram is formed, 13 denotes a clad constituting a waveguide, 14 denotes the same core, 15 denotes the same cladding, Is a grating composed of fine irregularities with a period of λ / n. Reference numeral 21 denotes external light composed of plane waves, 22 is guided light, and 23 is diffracted light.
This anti-counterfeit seal is a configuration in which external light is coupled by the grating 16 in order to satisfy the above-mentioned criterion (3), by crafting the external light coupling method to the waveguide hologram.

Next, the external optical coupling method will be described with reference to FIG. Here, for simplicity, it is assumed that the core 14 is made of only one layer. External light 21 that is a plane wave is applied to the input unit 11. In the input unit 11, a grating 16 having a period of λ / n is formed in the waveguide, where λ is the wavelength of the used light in the air and n is the refractive index of the core 14.
At this time, guided light 22 traveling substantially in the direction of the grating vector is generated by the interaction between the grating 16 having a period of λ / n and the external light 21. Here, if the output unit 12 on which the hologram is formed is formed in the direction of the grating vector of the input unit 11, the diffracted light 23 can be obtained.

  By adopting such an external optical coupling method, the above-mentioned criterion (3) can be satisfied. Since the size of the light beam of the input unit 11 is a millimeter (mm), if a plane wave 21 having a larger light beam is prepared, it is easy to perform “manual” alignment. Further, since the diffracted light 23 can be visually recognized, it is not necessary to prepare a CCD or other light receiver. However, as described above, when an automatic recognition area is necessary, a two-dimensional light receiver such as a CCD or CMOS detector may be used in combination with an image recognition technique.

  Although the above-mentioned criteria (1) and criteria (2) are satisfied to some extent as the characteristics of the waveguide hologram, even if it is an organization having a technique for producing a waveguide hologram, it is a legitimate manufacturer. It is important to provide a mechanism that cannot produce the same product unless it satisfies the criteria (6). A waveguide hologram type anti-counterfeit seal described below is provided with this mechanism.

[ Second Reference Form ]
FIG. 2 is a cross-sectional view showing a waveguide hologram type anti-counterfeit seal according to a second embodiment as a premise of the present invention . FIG. 2A shows a case where input light is not coupled to the waveguide, and FIG. Each shows a case where light is joined to a waveguide.

  In the figure, reference numeral 31 is a cladding, 32 is a core, 33 is a cladding, 34 is a surface irregularity, 35 is a uniform grating in the waveguide, 36 is a cladding, 37 is a core, 38 is a cladding, 39 is a surface irregularity, Reference numeral 40 denotes a uniform grating in the waveguide. Also, 41 is a plane wave input light, 42 is an input light modulated by the surface irregularities 34, 43 is an input light phase-modulated in advance so as to be coupled to the waveguide, and 44 is converted into a plane wave by the surface irregularities 39. The input light 45 is guided light.

This anti-counterfeit seal applies phase modulation to the light wavefront and uses the phase modulation pattern as an encryption key.
Here, phase modulation and its encryption key encryption will be described.
The case where the input light is not coupled to the waveguide (a) and the case where the input light is coupled to the waveguide (b) are different because the phases of the input light 41 and 43 are different.

  In the case where the input light is not coupled to the waveguide (a), the input light 41 is a plane wave, so that the input light 42 is modulated by the unevenness 34 formed on the surface of the cladding 33. The phase of the wavefront of the input light 42 is delayed at the convex portion (region A), whereas the phase is relatively advanced at the concave portion (region B). Therefore, if the phase of the wavefront of the input light 42 is shifted by 180 ° between the region A and the region B, the light that reaches the core 32 and is diffracted by the grating 35 is erased. Therefore, the input light 41, which is external light, is not coupled with the waveguide, and no reproduced image is obtained because no guided light exists.

  On the other hand, when the input light is coupled to the waveguide (b), the phase of the input light 43 is manipulated in advance, and when the input light 43 enters the clad 36 due to the unevenness 39 on the clad 36, it becomes a plane wave. Adjustment is made so that the input light 44 is converted. In this case, the guided light strengthens each other in the region A and the region B, coupling of the external light and the waveguide occurs, and the guided light 45 is generated. Therefore, a reproduced image from the output unit can be observed.

  Now, from the viewpoint of controlling the coupling strength between external light and guided light, it is the same as in the second embodiment described above, but instead of forming irregularities on the cladding, the grating of the input section itself is modulated. It is also possible to apply. This structure is a waveguide hologram type anti-counterfeit seal described below.

[ Third Reference Form ]
FIG. 3 is a cross-sectional view showing a waveguide hologram type anti-counterfeit seal according to a third embodiment as a premise of the present invention . FIG. 3A shows a case where input light is not coupled to the waveguide, and FIG. Each shows a case where light is joined to a waveguide.

  In the figure, reference numeral 51 is a clad, 52 is a core, 53 is a clad, 54 is a grating inverted in regions A and B, 56 is a clad, 57 is a core, 58 is a clad, and 59 is inverted in regions A and B. It is a grating. Also, 61 is a plane wave input light, 62 is a plane wave input light traveling in the cladding 56, 63 is a phase modulated input light so that it can be coupled to the waveguide, and 64 is phase modulated traveling in the cladding 56. Remaining input light 65 is guided light.

The case where the input light is not coupled to the waveguide (a) and the case where the input light is coupled to the waveguide (b) have the same structure, but the input is the same as in the second embodiment. The results are different because the lights 61 and 63 are different.
When the input light is not coupled to the waveguide (a), the input light 61 is a plane wave. Here, unlike the case of FIG. 2, the surface of the clad 51 is not uneven, so the input light 62 traveling through the clad 51 is also a plane wave. . However, since the inverted grating 54 in the region A and the region B formed in the core 52 is modulated to generate guided light having a phase different by 180 ° between the region A and the region B, they are erased. Therefore, since the input light 61 which is external light is not coupled to the waveguide, a reproduced image cannot be obtained.

On the other hand, in the case where the input light is coupled to the waveguide (b), the phase of the input light 63 is modulated in anticipation of the modulation of the grating 59, so that the guided light generated in the regions A and B is strengthened. . As a result, guided light 65 is generated and a reproduced image is obtained.
Also in this forgery prevention seal, it is possible to obtain a reproduced image only with modulation of external light.

In the anti-counterfeit seal of the second and third reference forms described above, it is possible to obtain a reproduced image only with external light modulation. Here, the phase modulation pattern plays the role of the encryption key. Here, for example, if the unit of phase modulation is 2 μm and the size of the input unit is 1 mm square, the phase modulation is 500 × 500 pixels. Further, since the phase patterns orthogonal to each other have the same pattern types as the number of pixels, 250,000 types of patterns can be taken.

としたとき、

を満たすことである。
但し、

はクロネッカーのデルタである。 Here, the phase is orthogonal means the phase of the (i, j) pixel in the phase patterns α and β, respectively.

When

Is to satisfy.
However,

Is the Kronecker Delta.

  In general, unlike an amplitude mask, it is expensive to manufacture a phase mask, so that the task of trying all 250,000 types of phase masks requires enormous costs and time. Therefore, it can be seen that even an engine having a technique for producing a waveguide hologram is difficult to duplicate unless the phase modulation pattern is known, and satisfies the above-mentioned criterion (6).

In the anti-counterfeit seal in the form of the second and third reference forms , the level of safety is increased by adding a configuration in which the grating period of the external optical coupling hologram of each layer differs depending on the layer as necessary. Further increase is possible.
When forgery is suspected, use layers, wavelengths and phase patterns that are not normally used.
When adding this configuration forgery-proof seal of the second reference embodiment, although the position of the input unit should be arranged so as not to overlap each other, forgery-proof seal of this configuration a third reference embodiment In the case of adding to, the input units may overlap each other.

  Assuming the same size as the above because there are two input parts, there can be 250,000 types of phase patterns. Therefore, there can be 250,000 × 250,000 types, that is, 62.5 billion types of phase patterns. It is effectively impossible to decipher and forge this. It is also effective to increase the security level by keeping the wavelength of the second layer and the existence of the second layer secret.

  The above-mentioned standard (4) can be satisfied by using an adhesive that is difficult to peel off, for example, a two-component mixed type epoxy adhesive. The more difficult standard is the standard (5), and it has a function of confirming the history of peeling when it is peeled off. This configuration is an article provided with a waveguide hologram type anti-counterfeit seal described below.

[ Fourth Reference Form ]
FIG. 4 is a partial cross-sectional view showing an article provided with a waveguide hologram type anti-counterfeit seal according to a fourth embodiment as a premise of the present invention . In the figure , reference numeral 71 denotes an adherend, and 72 denotes a waveguide. Hologram-type anti-counterfeit seal, 73 is a transparent cover seal (transparent seal), 74 is an adhesive portion between the adherend 71 and the transparent cover seal 73, 75 is an adhesive portion between the anti-counterfeit seal 72 and the transparent cover seal 73, 76 is This is an adhesion portion between the forgery prevention seal 72 and the adherend 71.

Specifically, the adherend 71 is a passport sheet, various licenses, or a membership card itself.
The forgery prevention seal 72 includes a clad 81, a core 82, and a clad 83. Here, only one layer of the core 82 of the anti-counterfeit seal 72 is shown, but a plurality of cores 82 may be provided.

Here, the adhesive strength between the adherend 71 and the transparent cover seal 73 is Asb, the adhesive strength between the adherend 71 and the anti-counterfeit seal 72 is Awb, and the transparent cover seal 73 and the anti-counterfeit seal 72 are When the adhesive strength is Asw and the adhesive strength between the core 82 and the clad 81, 83 is Acc,
Asb >> Acc (2-1)
Awb >> Acc (2-2)
Asw >> Acc (2-3)
Meet.

That is, the adhesive strength between the adherend 71 and the anti-counterfeit seal 72, the adhesive strength between the anti-counterfeit seal 72 and the transparent cover seal 73, and the adhesive strength between the transparent cover seal 73 and the adherend 71 Is larger than the adhesive strength between the core 82 of the optical waveguide and the clads 81 and 83.
As described above, when the transparent cover seal 73 is attempted to be peeled off, the transparent cover seal 73 is peeled off at the bonding portion between the core 82 and the clad 81 and 83 before the transparent cover seal 73 is peeled off, so that light is guided again. There is no. Therefore, the above-mentioned criterion (5) can be satisfied.

[ First Embodiment ]
5A and 5B are diagrams showing an external light coupling method and coupling apparatus according to the first embodiment of the present invention and a waveguide hologram type anti-counterfeit seal as a premise thereof. FIG. 5A is a top view, and FIG. Is a side view. In the figure, reference numeral 91 denotes an input portion of the forgery prevention seal, and 92 denotes the output portion. This anti-counterfeit seal has a clad 94, a core 95, and a clad 96 sequentially laminated on a polycarbonate sheet 93, and the back surface of the polycarbonate sheet 93 is used as an adhesive surface. Reference numeral 97 is a semiconductor laser, 98 is a convex lens, 99 is guided light, 100 is diffracted light, and 101 is vibration applied to the semiconductor laser 97 by vibration means such as a voice coil.

As the semiconductor laser 97, a 680 nm red semiconductor laser used for a light source of a magneto-optical disk is preferably used.
This anti-counterfeit seal is an elongated sheet having a thickness of 221 μm, a width of 1 mm, and a length of 3 cm. An input portion 91 made of a uniform grating having a size of 1 mm × 1 mm is formed at one end in the longitudinal direction of the sheet, and an output portion 92 having a size of 1 mm × 1 mm is formed at the other end. The uniform grating of the input unit 91 is a grating having a pitch of 0.44 μm × depth of 0.2 μm × duty of 50%, and is formed by pressing a stamper against the clad 94 of the input unit 91.

The output unit 92 is also formed with irregularities like the input unit 91, but this is not a simple grating but a hologram that creates an arbitrary wavefront.
This anti-counterfeit seal is produced using an ultraviolet curable resin with a core 95 having a refractive index of 1.52 and clads 94 and 96 having a refractive index of 1.50. The thickness of the core 95 is 1 μm, and the thickness of each of the clads 94 and 96 is 10 μm. The total thickness of the core 95 and the clads 94 and 96 is 21 μm. However, since this thickness is too thin to prevent wrinkles, it is lined with a polycarbonate sheet 93 having a thickness of 200 μm.

This anti-counterfeit seal is adhered to the adherend and the adhesive on the back surface 93a of the polycarbonate sheet 93. Accordingly, light is input from the opposite surface, that is, from above the cladding 96, and a reproduced image obtained by forming the diffracted light 100 is also observed from the opposite side of the adhesive surface.
Here, attention must be paid to coupling of external light to the input unit 91.
In general, in a thin film type hologram, Bragg conditions are not imposed on diffraction from a waveguide type hologram to the outside. The reason is that there is a degree of freedom in the diffraction angle of the diffracted light to the outside.

  On the other hand, in the case of coupling of external light to a waveguide, since the waveguide direction is constrained by the waveguide, the external light must have a degree of freedom. For this purpose, the traveling direction of the input light must be variable in a plane that includes the traveling direction of the guided light and is perpendicular to the waveguide surface. For this reason, the semiconductor laser 97 is vibrated 101 in the horizontal direction within the paper surface using a vibrating means such as a voice coil, so that the incident direction of the input light emitted from the semiconductor laser 97 is vibrated, and the oscillating input light is focused. A plane wave is generated by the input unit 91 using a convex lens 98 having a distance f.

Here, since the input unit 91 is small, the convex lens 98 may be a small object having a diameter of 1.5 mm and a focal length f of about 3 mm. Since the vibration 101 of the semiconductor laser 97 by the vibration means such as a voice coil is about several tens Hz and the amplitude is about 0.1 mm, the burden on the vibration means is small.
The output unit 92 is designed so that an image having a size of 1 cm × 1 cm is formed at a position where the diffracted light 100 is 10 cm away from the waveguide. As described above, if the distance from the waveguide is about 10 cm, it is easy to enlarge the image from 1 mm × 1 mm to 1 cm × 1 cm. In addition, observation with the human eye is easy if the size is 1 cm × 1 cm.

[ Second Embodiment ]
6A and 6B are diagrams showing a coupling method and coupling apparatus for external light according to a second embodiment of the present invention and a waveguide hologram anti-counterfeit seal as a premise thereof. FIG. 6A is a top view, and FIG. Is a side view. In the figure, reference numeral 111 denotes an input portion for a wavelength of 680 nm of the anti-counterfeit seal, 112 denotes an input portion for 532 nm, and 113 denotes the same output portion. In this anti-counterfeit seal, a 10 μm thick clad 114, a 0.7 μm thick 532 nm core 115, a 10 μm thick clad 116, a 1 μm thick 680 nm core 117, and a 10 μm thick clad 118 are sequentially laminated on a polycarbonate sheet 93. The back surface of the polycarbonate sheet 93 is an adhesive surface.

  Reference numeral 121 is a semiconductor laser for a wavelength of 680 nm, 122 is an optical fiber emitting end for a wavelength of 532 nm, 123 is a convex lens, 124 is vibration applied to the semiconductor laser 121 by vibration means such as a voice coil, and 125 is vibration means such as a voice coil. Is the vibration given to the optical fiber exit end 122. Reference numeral 126 denotes guided light, and 127 denotes diffracted light.

This anti-counterfeit seal is the same as the anti-counterfeit seal which is the premise of the above-described first embodiment in that it is a long and thin sheet having a width of 1 mm × length of 3 cm, but has a configuration including two core layers. It is different.
Further, the upper core 117 has a wavelength of 680 nm and the lower core 115 has a wavelength of 532 nm, and a YAG / SHG laser is preferably used. The input portion 111 for wavelength 680 nm is formed so as not to overlap the input portion 112 for 532 nm. The output unit 113 is common to the upper core 117 and the lower core 115, but of course, the layers are different.

The points that the refractive indexes of the cores 115 and 117 are 1.52, and the refractive indexes of the clads 114, 116, and 118 are 1.50 are the same as the forgery prevention seal that is the premise of the first embodiment .
The clads 114, 116, and 118 are all 10 μm thick, but the core 115 is 0.7 μm thick and the core 117 is 1 μm thick. Therefore, when combined with the 200 μm thick polycarbonate sheet 93, the total thickness is 231.7 μm. Thick.
The input portion 111 for 680 nm is configured by a grating with a pitch of 0.44 μm × depth of 0.2 μm × duty of 50%, and the input portion for 532 nm of pitch of 0.35 μm × depth of 0.2 μm × duty of 50%. It consists of a grating.

This anti-counterfeit seal can usually be checked only by the semiconductor laser 121 for 680 nm, but if forgery is suspected, the 532-nm diffracted light 126 is also checked. Here, a laser beam of 532 nm emitted from a YAG / SHG laser (not shown) is emitted from the optical fiber emitting end 122.
Further, the point that the vibration means such as the convex lens 123 and the voice coil is necessary is the same as in the first embodiment described above. The aperture and focal length of the convex lens 123, the vibration condition by the voice coil, and the like may be the same as those in the first embodiment .

[ Fifth Reference Form ]
FIG. 7 is a schematic diagram showing a phase modulation pattern of a waveguide hologram type anti-counterfeit seal according to a fifth reference embodiment as a premise of the present invention . FIG. 7 (a) is a diagram showing all quadrature phases composed of 2 × 2 pixels. Types (here, 4 types) of patterns are shown, (b) shows patterns of all types (here, 16 types) of 4 × 4 pixels, and (c) and (d) are 16 ×. Two types of patterns of 256 types of quadrature with 16 pixels are shown. In particular, (c) is a quadrature pattern assumed to be used in the present embodiment.
In these drawings, the phase is 180 ° different between the white portion and the shaded portion. That is, the white portions and the shaded portions have the same phase.

Here, an example in which input light is phase-modulated will be described.
In the forgery prevention seal of this reference form , the shape of the waveguide hologram is the same as that of the first embodiment described above except for the grating formed in the input unit 91 and the semiconductor laser 97 and the convex lens 98 which are the input lens system. It is the same as the anti-counterfeit seal which is the premise of

First, phase modulation will be described.
In general, when phase modulation using N × N pixels is used, N2 types of quadrature patterns can exist. FIG. 7 shows (a) 4 patterns of 2 × 2 pixels, (b) 16 patterns of 4 × 4 pixels, and (c) and (d) 2 patterns of 256 patterns of 16 × 16 pixels, respectively. .

These satisfy the above-described formula (1). Here, the 2n × 2n format is exemplified because the phase of each pixel can be only two types of 0 ° or 180 °, which is convenient for producing a phase mask for phase modulation of input light. Because it is good.
Here, it is assumed that a checkered phase pattern as shown in (c) is selected. In this figure, the 180 ° phase is different between white and black.
Since the input unit 91 has a size of 1 mm × 1 mm, each pixel size of the phase pattern of 16 × 16 pixels is 62.5 μm × 62.5 μm.

FIGS. 8A and 8B are configuration diagrams showing an input optical system applied to the anti-counterfeit seal according to the reference embodiment . FIG. 8A shows an actual phase pattern type optical system, and FIG. 8B shows a Fourier phase pattern type optical system. is there.
In the figure, 131 is an input part of a forgery prevention seal, 132 is a phase mask (phase modulation means), 133 is a convex lens, 134 is a semiconductor laser, 135 is vibration by a voice coil (not shown), 136 is a Fourier transform lens, and 137 is a collimating lens. It is. A convex lens 133 having a diameter of about 1.5 mm and a focal length f = 3 mm is used.

  In the actual phase pattern method (a), the phase mask 132 is disposed in close contact with the input portion 131 of the forgery prevention seal. The phase mask 132 can be manufactured by glass etching or plastic material stamping. Here, a plastic having a refractive index of 1.5 is used as a mask. The phase modulation of the phase mask 132 and the anti-counterfeit seal must be the same size. The phase mask 132 has a concave portion in the portion corresponding to the black portion in FIG. 7C and a convex portion in the portion corresponding to the white portion, and the height difference between them should be 450 nm.

Regarding the input part of the forgery prevention seal, for example, in the second reference embodiment , the black portion in FIG. 7C corresponds to the region A and the white portion corresponds to the region B, and the altitude difference of 450 nm. It is produced so that it may have.
In the third reference embodiment , the black portion in FIG. 7C corresponds to the region A and the white portion corresponds to the region B, and the phase of the grating is inverted between the region A and the region B. It is said that.

  On the other hand, in the Fourier pattern method (b), the same phase mask 132 as the actual phase pattern method is used. The Fourier transform lens 136 is the same as the actual phase pattern type convex lens 133, but is arranged at a position where the Fourier image of the phase mask 132 is formed at the input portion 131 of the anti-counterfeit seal. The collimating lens 137 is provided for collimating the laser beam, and the focal length may be about f ′ = 2 mm.

However, as the anti-counterfeit seal, the phase pattern of the input unit 131 is given as the complex conjugate phase pattern of the Fourier transform of the phase mask 132, so that the phase of each pixel is not given in two types and becomes a complicated pattern.
However, the merit of this method is that the tolerance for the positional deviation of the input beam is increased.

If the anti-counterfeit seal of the present invention is “lock” and the phase mask 132 is “key”, it is determined whether “lock” and “key”, that is, whether the anti-counterfeit seal of the present invention and the phase mask 132 match. You can authenticate with. In this case, it is possible to immediately determine whether authentication is possible at the stage of recognizing whether the anti-counterfeit seal of the present invention matches the phase mask 132.
Furthermore, if a forgery prevention seal in which a plurality of holograms are laminated is used, the level of safety can be increased.

[ Sixth Reference Form ]
The waveguide hologram type anti-counterfeit seal of the sixth reference form which is the premise of the present invention uses a forgery-preventing seal substantially equivalent to the anti-counterfeit seal which is the premise of the first embodiment . However, the core material is different.

Further, the article provided with the forgery prevention seal uses an Arton resin sheet having a thickness of 0.2 mm as the transparent cover seal 73 shown in FIG. The adherend 71 is paper.
The adhesive parts 74 to 76 all use a two-component mixed epoxy adhesive. Further, by using a fluorine-added ultraviolet curable resin for the core 82, the adhesive strength between the core 82 and the clads 81 and 83 is weakened.

As mentioned above, although each embodiment and reference form of this invention were demonstrated, this invention is not necessarily limited only to embodiment mentioned above, The objective said to this invention is achieved, and it says to this invention. Changes can be made as appropriate within the range having the effect.

It is a figure which shows the waveguide hologram type forgery prevention seal of the 1st reference form of this invention, (a) is a side view, (b) is a top view, (c) is the partially expanded cross section which expanded the input part. FIG. It is sectional drawing which shows the waveguide hologram type forgery prevention seal of the 2nd reference form of this invention, (a) is a case where input light is not couple | bonded with a waveguide, (b) joins input light to a waveguide Is the case. It is sectional drawing which shows the waveguide hologram type forgery prevention seal of the 3rd reference form of this invention, (a) is a case where input light is not couple | bonded with a waveguide, (b) joins input light to a waveguide Is the case. It is a fragmentary sectional view which shows the article | item provided with the waveguide hologram type forgery prevention seal of the 4th reference form of this invention. It is a figure which shows the coupling method and coupling | bonding apparatus of external light which concern on the 1st Embodiment of this invention, and the waveguide hologram type forgery prevention seal | sticker used as the premise , (a) is a top view, (b) is a side view It is. It is a figure which shows the coupling method and coupling | bonding apparatus of external light which concern on the 2nd Embodiment of this invention, and the waveguide hologram type forgery prevention seal | sticker used as the premise , (a) is a top view, (b) is a side view It is. It is a schematic diagram which shows various examples of the phase modulation pattern of the waveguide hologram type forgery prevention seal of the 5th reference form of this invention. It is a block diagram which shows the input optical system applied to the forgery prevention seal | sticker of the 5th reference form of this invention, (a) is an optical system of a real phase pattern system, (b) is an optical system of a Fourier phase pattern system It is. It is sectional drawing which shows a reproduction-only multiple hologram card.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Read-only multiple hologram card 2-1 to 2-n Clad 3-1 to 3-n-1 Core 4 Reflecting surface 5 Laser light 6 Convex lens 7 Waveguide light 8 Scattering factor 9 Diffracted light 10 Hologram image 11 Input part 12 Output part 13 Clad 14 Core 15 Clad 16 Grating 21 External light 22 Waveguide light 23 Diffracted light 31, 33, 36, 38 Clad 32, 37 Core 34, 39 Concavities and convexities 35, 40 Uniform grating 41 Plane wave input light 42 Modulated input light 43 Pre-phase-modulated input light 44 Input light converted to plane wave 45 Waveguide light 51, 53, 56, 58 Clad 52, 57 Core 54, 59 Inverted grating 61, 62 Plane wave input light 63, 64 Pre-phase modulation Input light 65 guided light 71 adherend 72 waveguide hologram forgery Stop seal 73 transparent cover seal (transparent seal)
74-76 Adhesive part 81, 83 Clad 82 Core 91 Input part 92 Output part 93 Polycarbonate sheet 94, 96 Clad 95 Core 97 Semiconductor laser 98 Convex lens 99 Waveguide light 100 Diffracted light 101 Vibration 111 Input part for 680 nm 112 Input part for 532 nm 113 Output unit 114, 116, 118 Clad 115 Core for 532nm 117 Core for 680nm 121 Semiconductor laser for 680nm 122 Optical fiber exit end 123 Convex lens 124, 125 Vibration

Claims (3)

Coupling of external light in a waveguide hologram having an external optical coupling hologram made of a grating that couples external light incident on the planar optical waveguide from the outside into the planar optical waveguide to be coupled to the planar optical waveguide. A method,
While making the light emitted from the laser light source or the output end of the optical fiber into a plane wave at the input part of the external light coupling hologram using a lens ,
By vibrating the laser light source or the emitting end in a direction perpendicular to the optical axis of the lens using a vibrating means, the incident direction of the plane wave incident on the input unit is vibrated,
A method for coupling external light in a waveguide hologram , wherein the plane wave is coupled as external light to the planar optical waveguide by making the direction of vibration in the incident direction coincide with the traveling direction of the guided light. Coupling of external light in a waveguide hologram having an external optical coupling hologram made of a grating that couples external light incident on the planar optical waveguide from the outside into the planar optical waveguide to be coupled to the planar optical waveguide. A device,
A laser light source ;
A lens that converts the light emitted from the laser light source into a plane wave at the input portion of the external light coupling hologram;
Vibration means for vibrating the incident direction of the plane wave incident on the input unit by vibrating the laser light source in a direction perpendicular to the optical axis of the lens;
With
An apparatus for coupling external light in a waveguide hologram , wherein the plane wave is coupled as external light to the planar optical waveguide by making the direction of vibration in the incident direction coincide with the traveling direction of the guided light. Coupling of external light in a waveguide hologram having an external light coupling hologram composed of a grating that couples external light incident on the planar optical waveguide from the outside into the planar optical waveguide to be coupled to the planar optical waveguide. A device,
A laser light source;
An optical fiber for guiding light emitted from the laser light source;
A lens that makes the light emitted from the exit end of the optical fiber a plane wave at the input portion of the external optical coupling hologram;
Vibrating means for vibrating the incident direction of the plane wave incident on the input unit by vibrating the emitting end in a direction perpendicular to the optical axis of the lens;
With
An apparatus for coupling external light in a waveguide hologram, wherein the plane wave is coupled as external light to the planar optical waveguide by making the direction of vibration in the incident direction coincide with the traveling direction of the guided light.

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