INTRODUCTION
Holograms have been introduced into Thailand since the late 80s. Nowadays we could say without exaggeration that in Thailand we can find plenty of occasions seeing examples of hologram applications.
Purposes of the applications are diversified. For examples, security or authentication for documents and ID cards, anti-counterfeiting and brand protection for commercial items, decoration of packaging, coupons for sale promotion, new artistic features for printing materials, etc. Two most important applications of holograms, however, are for security and packaging.
Thailand’s hologram market used to totally rely on imports from North America, Europe, Taiwan, and China. With the founding of Azure Photonics Co., Ltd., in 1999, hologram manufacturing industry had been established in Thailand, supplying the domestic hologram market and exporting to a number of countries.
BRIEF HISTORY
The birth of holographic technology took place in 1948 when Noble Prize laureate D. Gabor invented hologram [1] as a means for recording and replaying image in the form of light waves. The optical quality of those days’ holograms, however, was limited due to the lack of a genuine coherent light source. Therefore, with the coherent light waves available from the laser that was invented in 1959, E. N. Leith and J. Upatnieks further revised the hologram technique and spectacularly improved the optical quality of holographic images in 1962[2].
Since then a great number of techniques and materials had been proposed to exploit the tremendous potential of the hologram as a new media for recording, storage and replay of information and images. Among them were rainbow holograms proposed by S. A. Benton (1969) [3], and dot matrix “holograms” by different persons and companies (1980s – 1990s). Along with the evolution of holography, different technologies for mass production of holograms were also explored and developed.
Hologram embossing has been the most popular manufacturing technology. Developed in the late 70s, this technology is for manufacturing very high quality hologram replicas at very high speeds. In such a production process, the surface-relieved information on a rainbow hologram and/or dot matrix “hologram” (see explanation in the text to follow) is being transferred to replicas. The first significant commercial application of embossed holograms probably was the small 3D image hot-stamped on Visa cards in 1982. If the scale of the project and the impacts it brought about could be considered the start of an industry, then the embossed hologram manufacturing industry is now 30 years of age.
It might be worthwhile to mention Thailand’s first pilot factory for embossed hologram manufacturing that the author established and started operating in 1994 for NECTEC (The National Electronics and Computer Technology Center), on the campus of King Mongkut Institute Lardkrabang. The governmental program introduced, for the first time, hologram embossing technology into Thailand as part of the efforts for promoting photonics industries in the country. The achievement of the program was recognized internationally and in 1997 was among the sixteen hologram manufacturing countries listed in an authoritative sourcebook of the worldwide holographic industry, “Holography Market Place, the hologram industry reference text and sourcebook”[4].
BASIC HOLOGRAPHY
A unique media storing an image for replay, the hologram is totally different from other kinds of image media, such as photos, paintings, drawings, movies, and video/computer monitors, etc. The fundamental characteristics of the hologram lie in the fact that its image is handled in the form of light waves. In other words, the hologram does not store the image explicitly. Instead, what the hologram stores is a physical record of the light waves that came out from the imaging object. Using this record one can replay the light waves to optically realize the stored image. In practice, all what is needed to visualize a hologram image is just a beam of light. More accurately speaking, when illuminating a hologram with a beam of light in a particular manner prescribed for the hologram itself, the image will be replayed with all its colors and shapes in a 3D manner. No inks and color filters are involved in the recording and replay processes. And for embossed holograms, the embossing process of the hologram image on the plastic film takes only one single operation: all colors are recorded (“printed”) simultaneously onto the hologram replica in one single embossing operation (“printing”).
Pages : 1 2 3