stay Yesterday's article on full fit technology We also mentioned that the protective glass, touch screen and display screen of mobile phone screen need to be fitted twice in the production process. The display effect will be greatly reduced if the frame sticker is used only, and it is a problem if the full fitting yield is used. As the protective glass, touch screen and display screen go through a bonding process, the yield will be greatly reduced. If the bonding times can be reduced, it will undoubtedly increase the yield of full bonding. At present, there are several development directions: OGS scheme led by the original touch screen manufacturer, and panel manufacturer led On Cell and In Cell Technical proposal.
At present, the more powerful display panel manufacturers tend to promote the On Cell or In Cell solutions, mainly because they have the display production capacity, that is, they tend to make the touch layer on the display; However, touch module manufacturers or upstream material manufacturers prefer OGS, that is, touch layer is made on protective glass, mainly because of their strong manufacturing process capability and technology.
The common points of both can reduce the number of fitting times, which can also achieve cost saving and improve the yield of fitting. In addition, due to the lack of a touch layer, it can also achieve the purpose of saving material costs and achieving thinness. Apple's iPhone 5 uses the In Cell technology.
In-Cell
In-Cell It refers to the method of embedding touch panel functions into LCD pixels, that is, embedding touch sensor functions inside the display screen, which can make the screen thinner. At the same time, the In Cell screen Embed the matched touch IC, otherwise it is easy to cause wrong touch sensing signals or excessive noise. Therefore, for any display panel manufacturer, the threshold for entering the In Cell/On Cell touch screen technology is indeed quite high, and it still needs to overcome the difficulty of low yield. At present, the In Cell technology is used in addition to Apple's iPhone 5 and Nokia's Lumia920 。 The thickness of the iPhone 5 screen is estimated to be 2.54mm, and the In Cell thinning contribution is 0.44mm, accounting for about 25% of the 1.7mm thickness reduction.
The iPhone 5 has less touch screen than the iPhone 4S
Although Apple, a giant, has been vigorously promoting In Cell technology, it will still be limited to high-end smart phones in the next few years. The main problem is the yield rate, because In-Cell Once damaged, it is not only the touch screen that will be lost, display It will also be scrapped together, so the manufacturer In-Cell The yield requirement is higher.
On-Cell
On Cell It refers to the method of embedding the touch screen between the color filter substrate and the polarizer of the display screen, that is, the LCD panel is equipped with a touch sensor In Cell The technical difficulty has been reduced considerably. Samsung, Hitachi LG Wait for the manufacturer to On-Cell Rapid progress has been made on the structured touch screen. At present, On Cell Multi application to Samsung Amoled For panel products, the problem of uneven color caused by thinness and touch has not been overcome technically.
In Cell vs. On Cell
OGS
OGS technology The touch screen And protective glass Integrated together and plated on the inside of the protective glass ITO The conductive layer is directly coated and etched on the protective glass. Because a piece of glass and a bonding are saved, the touch screen can be thinner and cheaper. At present, domestic mobile phone brand manufacturers such as Tianyu Bumblebee 1, Jinli Fenghua and Xiaomi 2 have adopted OGS technology.
However, OGS still faces the problems of strength and processing cost. Since OGS protective glass and touch screen are integrated, they usually need to be strengthened first, then coated, etched, and finally cut. It is very troublesome to cut on the strengthened glass in this way. The cost is high, the yield is low, and some capillary cracks are formed on the edge of the glass. These cracks reduce the strength of the glass. At present, the insufficient strength has become an important factor restricting the development of OGS.
In Cell is the thinnest of the three solutions
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