Current status and issues of printing technology for electronic marking (2)
We are a big printing company in Shenzhen China . We offer all book publications, hardcover book printing, papercover book printing, hardcover notebook, sprial book printing, saddle stiching book printing, booklet printing,packaging box, calendars, all kinds of PVC, product brochures, notes, Children's book, stickers, all kinds of special paper color printing products, game cardand so on.
For more information please visit
http://www.joyful-printing.com. ENG only
http://www.joyful-printing.net
http://www.joyful-printing.org
email: info@joyful-printing.net
3. Print the antenna with conductive ink
The conductive ink is usually made by embedding silver flakes in a curable resin binder such as epoxy. In order to obtain the curing of the ink and the performance of the conductor as an electronic circuit, it is necessary to cure in time after printing, and the heating at this time The condition, even for the low curing type, needs to be set at about 130 °C. Therefore, a raw material having heat resistance and dimensional stability is required. For plastic film, it is common to stretch PET and PEN vertically and horizontally, but since heat shrinkage cannot be avoided, it is desirable to cure the ink at a lower temperature. In order to solve this problem, a method of curing using ultraviolet rays or electron wires has recently been proposed.
The use of conductive printed antennas has been adopted on IC public telephone cards, but has not yet become mainstream in terms of non-contact type IC cards such as railways or electronic money. The structure of these cards is formed by laminating 4 to 8 layers, and the surface is required to have high smoothness for pattern printing. Therefore, the main raw materials used are PVC and PETG (amorphous polyester) excellent in printability and thermal adhesion. The problem of low-temperature curing, which is only suitable for these materials, is clear and clear, and unnecessary adhesive layers can be reduced.
The electronic mark of the short-wave band is the same as the non-contact IC card, and the operating frequency is 22m at a wavelength of 13.56 MHz. Softness is required from the requirements of the roll-to-roll workflow and the curved surface of the trademark, but from the ink point of view, there are opposite requirements, so the design is difficult.
Through the efforts of ink manufacturers, there have been improvements in low resistance, low temperature firing, and flex resistance, but further improvements are needed to reach levels beyond the etched antenna.
However, the printed antenna has been re-optimized in terms of UHF tapes and microstrips that have recently received attention in practical use, and the reasons are as follows.
‧Because of the high frequency, the antenna length of the antenna is short, and the wiring resistance is not a problem.
‧The antenna can be formed in a single layer and in a simple shape.
‧High frequency, plus skin effect, the conductor film can be thinner
‧ Even if paper-based materials are used, the antenna can be produced by printing
‧Can also be made using original printing technology and equipment
In addition to the above, research is being conducted on inkjet printing antennas, die-cutting antennas made of punched metal foils, and transfer substrates such as hot stamping, which are low in cost and high in mass productivity. Manufacturing technology is the goal.
V. Points to be considered in antenna manufacturing
Looking at the technical prospects of electronic marking, when considering the practical use of printed antennas in the future, it is worthwhile to talk about the ideas for enlightenment.
1. Things to consider when designing the antenna
The shape of the high-band antenna seems to be very simple, and the design of the electromagnetic field characteristic for obtaining the best performance and the balance analysis of the radiation characteristics of the electric wave require a superb technique. For the setting of the resonance frequency, the Q value, and the directionality, the processing form, the use environment, and the like should be considered, and most of them are individually adjusted. In order to design a better antenna, we must first think of the production process, but also consider the factors that change due to the processing form and the use environment.
2, the thickness of the conductor film should be designed to what extent
The biggest point of printing is the thickness of the conductor film. From the point of view of the skin effect, the thickness should be minimized. The higher the signal frequency, the more current is concentrated on its surface. This phenomenon is called the skin effect, and the depth of its current conduction is called the skin depth. The required film thickness can be calculated from the main frequency of the electronic mark, and the UHF tape and the microwave band are only a few μm. Compared with the short-wave band, it can be regarded as absolutely thin, which fully demonstrates that the production of printed antennas can be realized.
3. How to treat the precision of the model
Regarding the mounting of the IC chip, the direct mounting of the bare chip is mainly based on the requirements of cost reduction and thinning. The trend is to miniaturize the chip body that is cheaper. The contact point of the chip line is connected with the two points of the power supply point on both sides of the antenna side. Due to the miniaturization of the chip, the contact point of the chip line and the two points of the power supply point on the antenna side are connected, and the antenna pad is required. The gap between the pieces is more precise. At present, the main body size of the mainstream IC chip is 1.0 mm angle up and down, and it is possible to develop a low-priced micro chip with an angular level of 0.4 mm.
Sixth, electronic tag chip installation
In order to understand the technology of electronic marking in depth, the current status of chip mounting is introduced.
With the installation process of the roll to roll antenna, from the point of view of high productivity, not only for electronic marking, but also for the use of non-contact IC cards. At present, in the manufacture of electronic markings, it is necessary to pay attention to the installation technology of general-purpose inexpensive materials. For this reason, in the case of unstable materials, it is more necessary to be able to firmly bond the chips. For a typical PET film, once it exceeds 100 ° C, the heat shrinkage rate becomes large, and when it exceeds 240 ° C, it melts. Like a printed circuit board, a high-temperature process such as soldering cannot be used.
In the case of electronic marking, since a low cost and high productivity are required, a flip chip in which a chip wiring surface is directly bonded to an antenna becomes mainstream, and it is necessary to form a bump electrode of gold or the like on the electrode on the IC chip side. The antenna base material can be directly connected as the material of the bump electrode, and high-purity gold is usually used. In the past, in order to cope with the strong press-in on the antenna wiring side, a palladium bump electrode having a high hardness was used, and the deformation of the contact portion and the reliability were ensured, and printing was performed by using a conductive resin to form a bump electrode. Technology is available.
In terms of the manner of bonding on the printed circuit board, it is roughly classified into metal bonding and pressure bonding. Among the pressure welding methods, the ACF method using an anisotropic conductive film is the mainstream from the practical consideration of a transmission IC that mostly uses an LCD. From the recent trend, in order to further reduce production costs, the NCP method using non-conductive materials has also been put into use.
Seven, the conclusion
Electronic markup is an indispensable technology for the information society, and it will usher in a popularization boom in the coming years. During the period, printing technology will show its talents. In addition, in view of the technical trend of high performance, thinness, and softness, it is expected that there will be many technological developments in the future due to the printing technology to solve printed semiconductors, bar codes, and signal source marks. This article details the technical issues related to antenna manufacturing. If you have a reference to the engineering and technical personnel who actually participate in the development of electronic marking, it is fortunate.