Firstly, what is full lamination? In the fierce competition of the smartphone market, major manufacturers are seeking hardware differentiation to highlight their own characteristics. Therefore, new terms such as IPS, SLCD, Retina, and ClearBlack emerge constantly, but often new technical terms emerge before we fully understand these new technologies. Recently, "full lamination" technology has become a new selling point for many mobile phone manufacturers. So, what kind of technology is this? Next, let's explore together.

1. The basic structure of a screen
A screen usually consists of three main parts, from top to bottom: protective glass, touch screen, and display screen. To ensure that these components can work smoothly together, they usually need to undergo lamination processing. This bonding process usually requires two steps, the first being between the protective glass and the touch screen, and the second being between the display screen and the touch screen. The bonding methods are mainly divided into two categories: full bonding and frame bonding.

2. Frame stickers
Frame sticker, also known as mouth glue bonding, is a simple bonding method that uses double-sided tape to fix the four sides of the touch screen and display screen. This method is widely used in many current display screens, and its advantage lies in the relatively simple manufacturing process and low cost. However, the drawbacks of frame stickers are also obvious. Due to the presence of an air layer between the display screen and the touch screen, light will refract when passing through, which seriously affects the display effect.

3. Full lamination
Full lamination technology, which uses water-based or optical adhesive to seamlessly bond the panel and touch screen, ensuring complete adhesion between the two. Compared to the frame pasting method, the full lamination technology significantly improves the display effect. At present, the widely used fully integrated screen solutions in the market mainly include OGS solutions, which are led by touch screen manufacturers; And the On Cell and In Cell technology solutions, led by panel manufacturers.

The advantage of full lamination technology is that it eliminates the air layer between the screens, thereby reducing the reflection phenomenon between the display panel and the glass, making the screen more transparent, and significantly improving the display effect of the screen.

IMacs using full lamination technology can reduce screen reflection issues by up to 75%. In addition, full lamination technology also brings many other benefits. Firstly, the problem of screen graying has been fundamentally solved, as the close integration of the touch module and panel not only enhances strength, but also effectively reduces the interference of display panel noise on touch signals. However, despite the significant advantages of full lamination technology, its yield rate is relatively low, which to some extent increases production costs. Therefore, the control of defoaming and bonding yield has become crucial, even more important than material cost.
In terms of full lamination technology, InCell, On Cell, and OGS are the three main screen technologies. In the production process of mobile phone screens, it is usually necessary to bond the protective glass, touch screen, and display screen twice. If the traditional framing method is used, the display effect will be seriously affected. The full lamination technology can significantly improve the display effect, but the yield rate has become a major challenge.
In order to reduce the number of bonding cycles and improve the yield rate, several new development directions have emerged in the industry. The OGS/TOL solution led by touch screen manufacturers, as well as the On Cell and In Cell technology solutions led by panel manufacturers, are all committed to reducing the number of bonding cycles. At present, strong display panel manufacturers are more inclined to promote On Cell or In Cell solutions because they have display screen production capabilities and tend to integrate touch layers into the display screen. However, touch module manufacturers and upstream material suppliers are more inclined towards OGS solutions, which have the advantage of strong manufacturing processes and technological capabilities.
The common goal of these two schemes is to reduce the number of bonding times, thereby saving costs and improving the yield rate. Meanwhile, by reducing one touch layer, material costs can be further saved and the product can be made thinner and lighter. It is worth mentioning that the Apple iPhone 5 has successfully adopted In Cell technology, fully demonstrating the huge potential of full lamination technology in improving display performance.
4. In Cell Technology
InCell technology involves directly integrating touch panel functionality into LCD pixels, that is, integrating touch sensors inside the display screen. This innovative design makes the screen thinner and lighter. However, to implement this technology, the screen must be equipped with a dedicated touch IC to avoid erroneous touch sensing signals or noise interference. Therefore, for display panel manufacturers, mastering InCell/OnCell touch screen technology and overcoming the problem of low yield is a major challenge. After adopting InCell technology, the screen thickness of Apple iPhone 5 significantly decreased to 2.54mm, with InCell technology contributing about 0.44mm, accounting for 25% of the total screen thickness reduction.
Although tech giants such as Apple are actively promoting the development of InCell technology, it is expected that this technology will still be mainly limited to the high-end smartphone market in the coming years. The main obstacle lies in the issue of yield rate, because once InCell technology encounters problems, not only the touch screen is damaged, but the entire display screen will be scrapped. Therefore, manufacturers have extremely strict requirements for the yield rate of InCell technology.
5. On Cell Technology
On Cell technology involves embedding a touch screen between the color filter substrate and polarizer of the display screen, which is achieved by equipping a touch sensor on the liquid crystal panel. Compared to In Cell technology, its technical difficulty has been reduced. At present, companies such as Samsung, Hitachi, LG, etc. have made significant progress in the field of On Cell structured touch screens, especially Samsung, whose AMOLED panel products have widely adopted this technology. However, the technology still faces some challenges, such as thinning issues and uneven color distribution during touch, which need to be further overcome.

6. OGS/TOL technology
OGS technology combines a touch screen with protective glass by coating an ITO conductive layer on the inside of the protective glass, enabling direct coating and photolithography on the glass. This technology saves a piece of glass and bonding process in traditional methods, making touch screens thinner and more cost-effective. At present, domestic mobile phone brands such as Tianyu Bumblebee

1, Jinli Fenghua, and Xiaomi 2 have adopted this technology. However, OGS technology still faces challenges in terms of strength and processing costs. Due to the integrated design of OGS protective glass and touch screen, its production process includes multiple steps such as strengthening, coating, etching, and cutting, which increases the complexity of manufacturing, especially the cutting difficulties in the glass strengthening process, resulting in high costs and low yield. At the same time, the capillary cracks generated by cutting can also affect the strength of the glass. These issues have become key factors constraining the further development of OGS technology. It is worth noting that in the internal documents of some touch manufacturers, OGS technology is also known as TOL (Touch On Lens), which has the same meaning and emphasizes the direct formation of ITO conductive film and sensor on the protective glass, achieving dual functions of protection and touch on a single piece of glass.

4. Comparison of In Cell, On Cell, OGS, and GG Screen Technologies

In Cell technology combines the touch panel and display screen into one, achieving perfect integration of touch and display by directly embedding touch elements inside the LCD panel. On Cell technology combines the touch screen with the display panel, using a special process to tightly integrate the two, thereby improving the sensitivity and display effect of the touch screen. OGS technology, on the other hand, saves costs and simplifies the production process by integrating touch screens with protective glass. GG technology is a traditional screen technology that achieves touch functionality by adding a touch layer on glass. These four screen technologies each have their own advantages, with certain differences in performance, cost, and manufacturing processes.