Nano-brick array holographic sheet applied to holographic anti-counterfeiting and design method for nano-brick array holographic sheet

Abstract

The invention relates to a nano-brick array holographic sheet applied to holographic anti-counterfeiting and a design method for the nano-brick array holographic sheet. Nano-brick array units in periodical arrangement are etched in the working surface of a substrate, a resonance-based reflective type working pattern is adopted, and the diffraction distance is 1-10[mu]m; the substrate can be divided into multiple unit structures corresponding to the nano bricks; all the unit structures are the same in lengths, widths and heights, the working surface of a single unit structure is square, and the length of side can be obtained by electromagnetic simulation optimization; in the nano-brick array units, the number of the nano bricks and the number of pixels in target images are equal; and the lengths, widths and heights of all the nano bricks are equal, and the orientation angles are designed according to phase distribution. According to the nano-brick array holographic sheet, redundant diffraction levels are omitted, good imaging quality and high efficiency are realized, and the energy is completely refracted basically; and compared with the conventional surface embossment type and refractive index type phase hologram, the nano-brick array holographic sheet has the advantages of small size, high integration, light weight, batch copying and the like, and can be widely applied to the aspects of laser trademarks, holographic anti-counterfeiting and the like.

Description

technical field [0001] The invention relates to the fields of micro-nano optics and polarization optics, in particular to a nano-brick array hologram based on a silicon nano-brick metamaterial and a design method thereof. Background technique [0002] Holographic anti-counterfeiting is an anti-counterfeiting technology developed by applying laser holographic technology. In the early laser holographic photos, the image can only be observed by using a laser as a light source to irradiate the hologram at a certain angle. Laser holograms can only be put into practical use if they can reproduce white light. At present, holograms that can be reproduced using white light mainly include rainbow holograms and image holograms. To be applied to anti-counterfeiting and trademarks, it must meet the conditions of large-scale batch replication. However, when the rainbow hologram is reproduced with white light, there will always be colored stripes, which greatly affects the visual effect. ...

AI Technical Summary

Problems solved by technology

At present, holograms that can be reproduced using white light mainly include rainbow holograms and image holograms. To be applied to anti-counterfeiting and trademarks, it must meet the conditions of large-scale batch replication. Replication, but when the rainbow hologram is reproduced with white light, there will always be colored stripes, which greatly affects the visual effect

Under certain conditions, the color blur of image plane holography can be unrecognizable to the naked eye, but it lacks the technical means of large-scale batch replication

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