At the time when ITO is in the ascendant, a new generation of touch technology Metal Mesh has quietly emerged. Due to the larger screen size, the corresponding data processing will also increase, so the resistance value requirements will also increase. When the size reaches 15 inches or more, the function of ITO will be limited. At this time, Metal Mesh, Graphene The advantages of other alternative materials are gradually revealed, and due to the maturity of Metal Mesh technology, it has become the most likely alternative material for mass production. With the development of Metal Mesh, Metal Mesh has been continuously expanded to medium and large size applications above 15 inches, including TV panels, teaching boards, and smart home applications.
According to the settings of Microsoft and Corning, Metal Mesh will be used in vehicles or implemented in 2020, and the reality seems to bring this application ahead of schedule. And the super-large size of 60 inches to 300 inches, such as display windows, construction glass, museums and large-scale exhibition venues, the application prospects of Metal Mesh are also very broad, and even the trend of entering the military market is also very clear. According to the data survey, in 2013, the global shipment of smart phones was 1.0 to 1.1 billion, supporting tablet and touch computers, and the market capacity of Metal Mesh was 600 million US dollars. If it is enlarged to small and medium-sized applications such as vehicle glass and teaching boards , this market capacity will be expanded to 2 billion US dollars, and the application to the 60-inch to 300-inch super-sized field will open up a market of 8 billion US dollars. Such a large market capacity is one of the reasons why many companies continue to evolve Metal Mesh process technology and seek leading mass production. In addition to the bright market prospects, Metal Mesh has obvious characteristics and cost advantages over ITO, especially in the application of large-size panels.
Metal Mesh has the characteristics of low resistance value, which can be valued from 5 ohms to 100 ohms, and all lines can be densely covered in the case of low resistance values. The flexible feature allows the touch screen to achieve narrow or even borderless borders. ITO or other metal wires are floating on the PET material, and the Metal Mesh nano-silver process wraps it in a plastic medium, which can be bent when bent. No disconnection, which is already used in some wearable watches.
At the same time, Metal Mesh can also be composited in a multi-layer structure, and two or more layers can be made on the PET material to save the cost of using the PET material. Its conductivity and light transmittance are also high, and it will not bring adverse effects on the visual experience due to the metal grid. From the perspective of cost analysis, taking the touch screen per square meter as an example, the material cost of Metal Mesh is only US$3, which is much lower than the average cost of ITO at US$24, and the equipment cost is only one-third of ITO. Customized to meet the different needs of different customers.
From the above point of view, the advantages of Metal Mesh are obvious and beyond doubt. However, large-scale mass production and commercial use of Metal Mesh is not possible with technology and equipment. More importantly, it requires the support of professional technical teams. This is the most severe challenge facing many manufacturers. At the same time, in order to realize the mass production of Metal Mesh touch panels, there are more problems to be solved besides the team.
First, the current industry's Metal Mesh yield rate is not stable, which is the first obstacle to the mass production of Metal Mesh touch technology. In addition, how to find the perfect match between Metal Mesh and LCD panels and how to achieve flexible production are important thresholds that affect the actual introduction of Metal Mesh into mass production in the future.
Second, in order to fully control Metal Mesh technology, manufacturers must have the ability to independently produce Metal Mesh, a key conductive material. Otherwise, even if touch panel manufacturers step into Metal Mesh touch technology, they will probably repeat the same mistakes and fall into The fate of "the same technology as the thin-film touch panel, and the key materials are controlled by people".
The third is the cost of the combination of Metal Mesh and LCD. When Metal Mesh is matched with LCD liquid crystal panel, the so-called Murray effect will appear. Generally speaking, if the conductive pattern of the silver wire of Metal Mesh can be adjusted and modified according to the different LCD panels to be matched, this problem can be effectively solved. However, individual design patterns may make Metal Mesh very expensive, which will make implementation difficult.
In general, the obvious advantages of Metal Mesh make it possible to become a next-generation touch material, especially in the application of large-size panels. Although Metal Mesh still faces a series of technical and market problems to achieve mass production, once these problems are solved, the era of its mass production application will come. At that time, large-scale touch interaction will gradually penetrate into our daily life, bringing a real smart life experience to the general public.
Early metal grids are metal grid patterns formed on plastic films such as PET using metal materials or oxides such as silver and copper. Its theoretical minimum surface resistance value can reach 0.1 ohm/□, and it has the function of electromagnetic shielding to reduce signal interference; however, the touch sensor pattern produced by it has a slightly thicker line width (especially if the line width exceeds 5μm), which makes it difficult to The Swiss interference ripple is very obvious, and it is only suitable for the display screen with a long viewing distance. The Japanese companies that developed earlier were Fuji and Gunshi, both of which began to produce metal mesh films in 2009 and then provided them for use by touch panel manufacturers. Fuji and Gun are directly supplying touch sensors and even modules to help terminal manufacturers lower the technical barriers to entry. In addition to these two, although Atmel, an American company, provides solutions from touch IC to transparent conductive film, its technology development is relatively late, and its shipments are often affected by process problems during the production process, while mainland companies are affected by the development of Atmel. Influenced by the results, an attempt was made to strengthen both R&D and manufacturing capabilities to obtain a complete solution.
The basic technology of metal mesh can be mainly divided into three types. The first is to directly use metal ink for screen printing; Grids are generated; the third technique is similar to the second, except that the metal in it is changed to silver bromide, which is chemically reduced to silver. Fuji, which originally produced silver-salt film, adopted the third method and became the world's leading manufacturer of metal mesh films, while other manufacturers, such as Gunze and mainland manufacturers, adopted the first technology, while Atmel adopted the second technology. technology, and there are others that independently develop other technologies, such as the Japanese company Achilles (Achilles), but it has not yet been put into practical use.
The mass production of metal grids, in the first half of 2013, Taiwanese manufacturers ASUS 7-inch tablet PCs, mainland manufacturers Lenovo NB, etc. took the lead in adopting metal grids; mainland manufacturers Huawei and Japanese manufacturers NEC smart phones also joined successively. In particular, the latter is produced by metal evaporation technology. In addition, 20 also have GFF solutions or MetalMesh technology models equipped with thin-film touch control process. In 2014, although this technology is still in its infancy, it has potential in the field of medium and large size products on the road of replacing ITO's thin-film touch panel.
Although MetalMesh is a topical topic in the market due to the large number of invested manufacturers, and the price is not expensive, so far MetalMesh has not been really mass-produced. As pointed out by Li Xiangyu, general manager of SuperC_Touch, the problem is that the light transmittance is not enough. In the process of patterning to form thin lines, 95% to 99% of the touch sensing coating area must be removed, resulting in a decrease in touch signal. 20 to 100 times, it is difficult to support touch ICs today; secondly, in order to make it invisible to the eyes, the metal line width must be less than 5 microns, and the yellow light development process or precision printing technology is used, but the cost of both is high. Therefore, in order to keep the metal wire width below 5 microns from breaking, to solve the problem of metal reflection, and to oxidize the material, the metal grid technology has been tested.
In recent years, with the continuous improvement of materials and technologies, MetalMesh is no longer a myth, and related technical difficulties have been overcome, fully realizing the maximization of MetalMesh mass production. Mr. Wang Lei, general manager of CINOTOP, pointed out that the use of advanced light and shadow imaging technology combined with over-etching method to form ultra-fine lines, so that the mesh of Metal Mesh can meet the needs of various products.
The produced metal mesh products not only meet the customer's reliability test requirements, but also extend the integrated touch and communication products, allowing integrators to save the trouble of antenna modules
