Talking about the Advantages of Screen Printing in the Production of Smart Labels

As the transponder of the RFID (radio frequency identification) system, the smart tag is the most advanced non-contact sensing technology. It has a series of outstanding advantages, such as large data memory capacity, high data density, good anti-pollution ability and durability, almost no impact on the pollution of water, oil and chemicals, long reading distance, high speed, and good data security performance. and many more. The facts have proved that with the development of RFID and materials technology, smart labels will replace the currently popular bar codes and become the new darling of retail, packaging and logistics.

RFID is a non-contact automatic identification technology that automatically recognizes target objects and obtains relevant data through radio frequency signals. The RFID system generally consists of three modules: a smart tag, a reader, and a radio frequency antenna. The system works as follows. When a tag is exposed to a radio frequency signal generated by a system reader and transmitted by a radio frequency antenna, the internal line generates an induced current and the chip is activated; the chip transmits its own information through the tag's built-in antenna (coil); RFID system The RF antenna receives the carrier signal sent by the tag and transmits it to the reader via the antenna regulator. The reader then demodulates and decodes the received signal to obtain the data information contained in the tag.

From the working principle of the RFID system, the reader of the system can read multiple smart tags at the same time, and the identification of the tags is completely non-contact automatic recognition. Without any manual intervention, only a variety of objects to be labeled with smart tags are needed. Move through the RF area. Therefore, using smart tag technology saves the manpower necessary for bar code technology, and at the same time it also improves the sales efficiency of supermarkets, which facilitates consumers and saves consumers time.

The relatively high cost of labels is a bottleneck in the promotion process of smart labels. Market research shows that the unit price of each label currently ranges from about 20 cents to 1 US dollar; generally speaking, for a single item, the acceptable label price is 5 cents. Therefore, the overall promotion of smart labels should be mainly from two aspects: to further improve the performance of the label and reduce the production cost of the label.

The smart tag consists of a (silicon) chip, a built-in antenna (coil), and a substrate. At present, the performance and price of the chip and the substrate are basically stable, so the advantages of various manufacturing methods can only be reflected in the optimization of the manufacturing process of the tag's built-in antenna and reducing the manufacturing cost of the antenna. Judging from a method, the built-in antenna of the tag is functional and cost-effective. It should meet at least three standards: 1 The antenna should have high electrical performance (impedance); 2 It is easy to install the chip on the antenna. ; 3 can carry out large-scale, low-cost production.

At present, there are mainly three methods for producing smart tag antennas.

Etching method. Also called subtraction production technology. Firstly, a flat copper foil is laminated on a plastic film by this method; then, a photosensitive paste is coated on the copper foil, dried, passed through a positive film (a pattern having a desired shape) and lighted; and put into a chemical developer. At this time, the photosensitive part of the photoresist is washed away to expose the copper; finally put into the etching bath, all the copper that is not covered by the photoresist is etched away, so as to obtain the desired shape of the copper coil.

· Coil winding method. The label coil is wound on a winding tool and fixed. At this time, the number of turns of the antenna coil is required to be larger (typically 50 to 1,500 turns). This method is usually used when the frequency range is small (for example, less than 135 kHz) and the label is not considered in the market.

Conduction ink printing method. Also known as additive manufacturing technology. Since the tag antenna has a relatively rough shape, it can be realized by printing (adding) a conductive ink on the substrate. Currently, a screen printing method is mainly used to produce a UHF (Ultra High Frequency) tag antenna.

The advantages of screen printing antenna

Screen Printing Labels The built-in antenna uses conductive ink.

Conductive ink is a kind of conductive composite material formed by metal conductive particles (silver, copper, carbon) dispersed in the connecting material. After printed on the substrate, it acts as a wire, an antenna, and a resistor. The ink is printed on a flexible or rigid substrate (paper, PVC, PE, etc.) to make a printed circuit, and an antenna printed with conductive ink can receive RFID-specific radio frequency signals. Smart tag built-in antenna using conductive ink screen printing method has many advantages over other methods (such as copper etching method), can be said to be a green, stable, low-cost solution, is a high-volume production of low-cost tags is a This kind of ideal craft method, its advantage manifests in the following several aspects:

1. Low cost

A significant advantage of using the method of screen printed conductive ink to make a tag built-in antenna is low cost and easy operation. The low-cost nature of this method is reflected in two aspects.

(1) screen printing process. First of all, the investment in the introduction of screen printing equipment is much cheaper than the introduction of copper etching equipment; in addition, since there is no need for additional investment in the screen printing process due to environmental protection requirements, the maintenance cost of production and equipment is lower than that of the copper etching method. In fact, the maintenance of copper etching lines and the disposal of wastes (such as residues in chemical etching tanks) themselves require a very expensive fixed cost, and thus also increase the single piece cost of the tag.

(2) conductive ink. First of all, from the material cost, the conductive ink is cheaper than the etching metal coil; In addition, from the material consumption, the etching process consumes a lot of metal, and the conductive ink printing antenna or circuit is fast and low cost. efficient.

2. Easy to operate

As an additive manufacturing technique, screen printing technology is itself an easy-to-control, one-step process compared to subtractive manufacturing techniques such as etching. In the screen printing process, there are no technical problems such as ink balance in the offset printing, replacement of the blanket, ink emulsification, and adjustment of the ink fountain key, so it has an easy operation performance.