OGS technology evolution and touch screen development status

OGS technology integrates the touch screen with the protective glass, coats the inner side of the protective glass with an ITO conductive layer, and directly coats and photolithographs the protective glass. Since a piece of glass and one lamination are saved, the touch screen can be made thinner and at a lower cost. Currently, domestic mobile phone brand manufacturers such as Tianyu Bumblebee 1, Gionee Fenghua, and Xiaomi 2 have all adopted OGS technology.

OGS manufacturing flow chart

Analysis of the evolution of OGS technology

1. OGS will become the dominant technology direction of the touch screen industry in recent years. OGS (One Glass Solution, i.e. integrated touch screen) has three benefits: (1) saving the cost of a layer of glass and reducing the cost of one bonding; (2) reducing weight; (3) increasing light transmittance. OGS can better meet the ultra-thin requirements of smart terminals and improve the display effect. It is the inevitable choice for high-end brand terminals next year.

2. The evolution of OGS technology has fallen into a state of flux, and the conflict of interests between touch and panel manufacturers has intensified. In terms of the specific direction of OGS technology evolution, touch and panel manufacturers have diverged in their technology choices. In order to maintain an independent industry chain, touch manufacturers have integrated upstream tempered glass CoverLens and proposed the TOL (TouchOnLens) solution; while panel manufacturers tend to in-house the touch process and proposed two solutions: On-cell and In-cell.

3. Sheet method has the greatest potential in TOL solutions. The Sheet method led by Wintek has always been troubled by problems such as secondary edge strengthening, and corresponding solutions are now available. Compared with the Picec method proposed by TPK, the Sheet method can use higher-generation substrates and has more scale effect advantages after mass production.

4. On-Cell and In-Cell matured faster under Apple's leadership. Samsung's monopoly on AMOLED has posed a higher challenge to the display effect and thinness and power saving of Apple's iPhone. Apple turned to seek cooperation with panel manufacturers Sharp and TMD, and invested a lot of money and technology to support the research and development of the screen and touch technology of the new generation of iPhone. The iPhone5 has adopted In-cell technology.

5. In-Cell will become the final direction of OGS. In terms of thinning effect, In-Cell is about 0.4mm thinner than TOL and about 0.3mm thinner than On-Cell. The "noise reduction" problem currently encountered by In-Cell requires in-depth cooperation between panel manufacturers and high-end driver IC manufacturers to solve. Apple has such industry chain integration capabilities, and mass production is only a matter of time.

6. TOL has advantages in technology maturity and mass production time, and will be the most cost-effective technology in 2012. In the future, the competition between Apple and non-Apple camps will focus more on panels, and the core position of touch technology is declining. From the current situation of industry chain competition, the non-Apple camp has a broader market space, and the focus will sink to the middle and low end. The cost-effective TOL technology (Sheet Process) will become the dominant technology in the middle and high-end market, accelerating the replacement of the current G/G bonding solution.

Current status of touch screen industry

Projected capacitive touch panels that target multi-touch applications are mainly divided into two technologies: film type and glass type. Apple uses glass projected capacitive (glass type), while non-Apple uses film type PET. The current mainstream film structure is to photolithography or print ITO on PET film, with a protective glass on the outside, called GFF (Glass-Film-Film) structure, while the mainstream glass structure is to make the touch sensor on ITO glass, with a protective glass on the outside, called GG (Glass-Glass) structure. The former is limited by the fact that high-end ITO film materials are in the hands of a few Japanese companies, and the latter has a generally low GG bonding yield, which are the main reasons for the high cost of projected capacitive touch modules.

In order to effectively reduce the cost of touch modules and meet the market trend of thinner terminal consumer electronic products, touch industry players have actively started research and development to reduce the use of ITO film or ITO glass in the past two years, and have developed OGS, embedded touch or GF film technology. OGS technology integrates ITO glass and protective glass into one piece of glass, which not only reduces one piece of glass, but also saves a lamination process. It is about 0.4 mm thinner than two-piece G/G products, and is estimated to save about 50% of the cost.

Currently, the professional touch module manufacturers TPK, Wintek, and Dahong are the most active in developing OGS. Among them, Wintek's OGS has the fastest mass production and shipment speed. In 2011, it has been applied to many international brand smartphones and introduced to domestic first-tier tablet computer manufacturers. In early 2012, domestic touch industry companies also actively invested in the development of OGS products and began to send samples to customers for certification. If the problems of glass strengthening and production efficiency are overcome, OGS is expected to become the new mainstream of glass touch technology in the future.

Compared with the external professional touch module manufacturers actively deploying OGS technology, major TFT or AMOLED panel manufacturers tend to develop embedded technology (In Cell Touch), directly making the sensor in the display, which can be roughly divided into two technologies: In-cell and On-cell. The advantage of embedded touch is that it can also save a piece of glass and a bonding process, but since the panel manufacturer that introduces embedded technology must have LTPS technology, the entry threshold is relatively high, and the current process yield is still low, it will not have much impact on external touch panels in the short term.

However, as Apple supports embedded technology and has recently been actively cooperating with Japanese and Korean companies in development, and Samsung will also launch AMOLED application products with on-cell touch technology this year, the future of embedded touch cannot be underestimated.

In 2012, glass touch panels are competing with OGS and embedded technologies, setting off a wave of competition for the thin and light touch technology market. Industry insiders pointed out that under the development trend of OGS in the touch market, in addition to the original sensor and module manufacturers, protective glass manufacturers and color filter manufacturers also have the opportunity to enter the touch module field, and the revolution of the touch industry is ready to take off.

It is worth noting that Samsung and its cooperative suppliers in South Korea recently planned to build the latest OGS production line and actively set up related strategic supply chains. For example, the key OGS sputtering equipment technology is expected to be provided by Taiwan manufacturer Beiru Precision. It is understood that Samsung Group may reverse the past touch module factory procurement model and set up part of the touch production line in house, revealing Samsung's change in touch supply chain strategy, which is worthy of the attention of domestic industry players.