Commercialization of reflection holograms and its application

In recent years, rainbow molded hologram anti-counterfeiting labels have been widely used in China, and their characteristics have been familiar to people. With the development of holographic anti-counterfeiting technology, another kind of anti-counterfeiting label for holograms - the anti-counterfeiting label for reflection holograms - has also entered the market quietly. Several companies in Taiwan Province and the United States have successively demonstrated and introduced this use of photopolymerization in China. Reflective hologram anti-counterfeit labels made from the back sheet of material media are refreshing. At present, this type of anti-counterfeiting label has been used in imported cameras in 1996, the National Ninth Five-Year Spark Program promotion project in 1998, and international Sanshou competition tournament tickets in 1998. It has achieved great success and made people realize once again that the application of laser holography technology. Anti-counterfeiting artistic charm and anti-counterfeiting efforts.
What is a reflection hologram When an incident laser hits a transparent medium, part of the light is used as a reference light, and the other part of the light is transmitted through the medium to illuminate the object and is then scattered by the object back to the medium as object light. The object light and the reference light interfere with each other to generate a multi-layer interference fringe surface in the medium. After the medium film is processed, multiple transparent reflection surfaces are generated in the medium (for example, there may be more than 20 reflection surfaces in a 6 micron emulsion layer). . At this time, the object is no longer present, and when the hologram is irradiated with a white light source, the virtual image of the original can be seen against the reflected light, and this is called a reflection hologram.
Application of reflection holograms The reflection holograms described above are monochromatic and do not exhibit rainbow changes. Three-dimensional imaging can have a great depth and viewing angle. Because the interference fringe surface generated by it penetrates deep into the interior of the medium instead of being concentrated on the surface, it cannot be copied by molding. This kind of hologram was used in the field of cultural relics display, treasure displays, souvenirs, decorations, holographic elements and other fields. The medium used was silver salt, dichromate gelatin and so on. The use of reflection holograms for anti-counterfeit markings is a recent matter. The medium used is photopolymer, which can be processed in real-time and facilitates the automation of mass optical copies.
Commercially available true color three-dimensional holograms come out. Dai Nippon Printing Co., Ltd. (DNP) has recently launched a commercially available true color 3D photopolymer hologram film that can be mass-reproduced. Color three-dimensional photography, publishing and printing, product promotion, packaging and decoration, security security, souvenir production and other aspects have been applied.
The company has successfully produced a series of true color 3D holograms, among which 3000 "POCKET MONSTER" holograms are used for gift card making; 12,000 "ASTRO BOY" holograms are used for Promotion/commemoration card making; 5,000 true color 3D holograms used in the field of trade; in addition, they also made "PARROTS IN THE JUNGLE" on the cover of "MARKET PLACE" magazine (8th edition) published by the world. The parrot in the) true color 3D hologram. These true color three-dimensional holograms are vivid in color, high in reproduction image brightness, and large in field of view, which have attracted the attention of the international holographic community and are considered as new breakthroughs in commercial true color three-dimensional holography.
The recording material of commercially available true color three-dimensional photopolymer hologram color that can be bulk-reproduced by Japan DNP Company is a new full-color photopolymer holographic recording material of HRF 800001-15 recently introduced by DuPont, which is characterized by various visible light. The high sensitivity of the wave and the wide range of refractive index change make it possible to produce holograms with high image brightness and a large field of view.
Different holographic recording materials have different characteristics:
1 silver salt emulsion holographic medium, high sensitivity, but the refractive index range is small;
2 dichromated gelatin holographic media, refractive index changes in a wide range, but the sensitivity is low;
3 photopolymer emulsion holographic media, high sensitivity, refractive index change range is also very large, suitable for making high-brightness reproduction, large hologram field of view. In addition, this medium can be processed in real time with a dry process (using only UV irradiation and heating, which eliminates the traditional wet processing methods). Therefore, the characteristics of photopolymer emulsion holographic media are particularly suitable for making holographic masters. After a large number of contact copies.
Du Bangguang Polymer Latex has a thickness of approximately 15 μm. It is generally applied to a 0.002 inch thick Mylar polyester base film, and a 0.00092 inch Mylar polyester film is applied to the surface of the latex.
Japanese DNP company introduced their production steps:
1Design, decided according to the needs of customers;
2 model making, elaborate production and color of three-dimensional objects or two-dimensional planes;
3 master production;
4 copy, exposure on a special dedicated machine;
5 processing, using heating and ultraviolet irradiation to create a stable, bright hologram reproduction, DNP company uses DuPont's oven and composite machine;
After 6 processing, according to the needs of customers for painting, die-cutting and other steps.
DNP's production continues to increase, making it possible to make multiple rolls of holograms per day, each roll being one foot wide and 500 feet long. The price of the hologram is calculated as 2 inches x 2 inches, which is about 70 yen (about 0.5 USD).
Hans Bjelkhagen, an American holographic expert, believes: “The new full-color photopolymer holographic recording material recently introduced by DuPont Company is particularly suitable for true-color three-dimensional holography, although its sensitivity is slightly higher than that of silver salt emulsion holographic media. Low, but it can be processed in real-time with a dry process, so it is particularly suitable for making large-scale contact copies after the silver salt master is made. When recording, attach the film to the glass plate with matching liquid (be careful not to make the glass plate Bubbles or dust remain on the surface. To achieve mass production, special machines are required for copying. The RGB (red, green and blue) trichromatic ratio can be taken as 4:1:2, and 3 lasers can be used for scanning at the same time. The intensity can be selected as 10mm joules per square centimeter.After the laser scanning exposure is over, it needs to be exposed to strong white light or ultraviolet light.DuPont proposed that the exposure intensity can choose 10 millijoules per square centimeter, the wavelength can be selected from 350 to 380 nanometers. Heated in an oven at a temperature of 120°C for 2 hours to enhance the brightness of the reproduced image.
DNP claims that the lasers they use are: helium ion lasers for red light; argon ion lasers for green light, diode-pumped solid-state lasers, dye lasers; and argon ion lasers for blue light.