Preliminary Exploration of ProMotion Technology: The Secret of Adaptive Refresh Rate


ProMotion， This name itself contains the dual meanings of "professional" and "dynamic", indicating a major innovation in Apple's screen display technology. In short, ProMotion technology is a mechanism that can automatically adjust the screen refresh rate based on the current display content, with refresh rates ranging from a minimum of 10Hz to a maximum of 120Hz. This means that when you swipe the screen to browse web pages, play games, or watch high frame rate videos, the screen can present incredibly smooth visual effects with a refresh rate of up to 120Hz; When displaying statically or performing low-intensity operations, such as reading e-books, viewing photos, or in standby mode, the screen will lower the refresh rate to a more suitable level to save power.



Why choose adaptive refresh rate?


The reason why Apple introduced adaptive refresh rate technology in the iPhone 13 Pro series is due to profound considerations and user demand insights.



Improving user experience: Firstly, a high refresh rate screen can bring a smoother visual experience. For gamers, a high refresh rate of 120Hz means lower latency and finer transitions, taking the gaming experience to the next level. For daily users, whether sliding the screen, scrolling through web pages, or switching applications, they can feel an unprecedented sense of smoothness. However, if the phone always maintains a 120Hz refresh rate, it will not only consume a lot of electricity, but may also cause problems such as device overheating due to unnecessary performance output, affecting the overall user experience.


Optimizing energy management: As stated by Apple, one of the core advantages of adaptive refresh rate is its excellent energy management capabilities. Mobile screens are one of the largest energy sources in smartphones, especially when the brightness is high and the refresh rate is fixed at a high level. Through ProMotion technology, the iPhone 13 Pro series can dynamically adjust the refresh rate according to actual needs, effectively avoiding unnecessary energy waste. For example, when users are still viewing pictures or documents, the screen refresh rate can be reduced to 10Hz or even lower, significantly reducing battery consumption and extending battery life. This is undoubtedly a huge blessing for users who frequently go out and have high requirements for mobile phone battery life.


The combination of intelligence and efficiency: The implementation of ProMotion technology relies on Apple's powerful hardware and software integration capabilities. It requires seamless collaboration between screen driver chips, operating systems, and various applications to ensure real-time and accurate refresh rate adjustments. This intelligent adjustment mechanism not only reflects Apple's technological innovation, but also its commitment to pursuing the ultimate user experience. The algorithm predicts the user's behavior and adjusts the refresh rate in advance, so that each screen refresh is just right, which not only ensures the smoothness of visual effects, but also realizes the efficient use of energy.


Challenges and Solutions Behind Technology


Implementing adaptive refresh rate is not an easy task, as it requires the phone to find a perfect balance between hardware design, software development, and user experience. Apple has invested a significant amount of research and development resources in this regard, overcoming multiple technical challenges



Hardware upgrade: The iPhone 13 Pro series is equipped with more advanced display driver chips, which have stronger data processing capabilities and lower power consumption, providing a hardware foundation for fast and accurate refresh rate adjustment.
Software optimization: The iOS system has been deeply optimized to ensure that the system and third-party applications can fully utilize the advantages of ProMotion technology. Developers need to update their applications to adapt to display effects at different refresh rates, which requires Apple to provide detailed development guidelines and technical support.


User experience considerations: When designing ProMotion technology, Apple fully considered the differences in user perception. For example, the change in refresh rate between fast and slow swiping needs to be smooth enough to avoid giving users a sense of abruptness. This requires fine tuning and extensive user testing.


Impact on the industry and future prospects


Apple's introduction of ProMotion technology in the iPhone 13 Pro series not only enhances the competitiveness of its own products, but also has a profound impact on the entire smartphone industry. On the one hand, it has promoted the innovation of screen technology, prompting other manufacturers to accelerate their research and development pace in adaptive refresh rate technology; On the other hand, it has also raised consumers' expectations for the refresh rate of mobile phone screens, making high refresh rate and adaptive adjustment a standard feature of high-end smartphones.



Looking ahead to the future, with the continuous advancement of technology, adaptive refresh rate technology will become more mature and its application scenarios will become more extensive. For example, combined with AI and machine learning technology, mobile phones can more intelligently predict the user's next operation, adjust the refresh rate in advance, and further improve the user experience. Meanwhile, with the popularization of technologies such as 5G and AR/VR, adaptive refresh rates will leverage their unique advantages in more fields, bringing unprecedented interactive experiences to users.



In short, the ProMotion adaptive refresh rate technology in the Apple iPhone 13 Pro series is another important milestone for Apple in pursuing the ultimate user experience. It not only demonstrates Apple's leading position in technological innovation, but also sets a new benchmark for the entire smartphone industry, indicating the direction of future smartphone screen technology development. With the continuous evolution of technology, we have reason to believe that future smartphones will serve our daily lives in a more intelligent, efficient, and energy-saving way, allowing the light of technology to illuminate every corner.

The rise of full lamination technology
The structure of a screen can be roughly divided into three parts: protective glass, touch screen, and display screen, which are arranged in sequence. To ensure the perfect presentation of the screen, it is usually necessary to perform two bonding operations: one between the protective glass and the touch screen, and the other between the display screen and the touch screen. And the film we are familiar with in daily life is actually the bonding process between the protective glass and the protective film. Although it may seem simple, it also requires exquisite bonding technology.

Screen bonding technology, according to its bonding method, is mainly divided into two categories: full bonding and frame bonding. Frame adhesive, also known as mouth glue bonding, refers to the simple fixation of the four sides of the touch screen and display screen through double-sided tape. This is the bonding method currently used by many display screens, which has the advantages of simple process and low cost. However, due to the presence of an air layer between the display screen and the touch screen, the refraction of light can affect the display effect, which is the main drawback of frame pasting technology.

Full lamination technology uses water-based adhesive or optical adhesive to completely stick the panel and touch screen together without any gaps. Compared to frame stickers, it provides a better display effect. The common full screen solutions in the market mainly come from OGS solutions from touch screen manufacturers, as well as 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, reduces the reflection between the display panel and glass, makes the screen more transparent, and thus improves the display effect of the screen. IMacs using full lamination technology can reduce reflection issues by up to 75%. In addition, full lamination technology can effectively prevent screen dust from entering and enhance the strength of the touch module. More importantly, it can significantly reduce the interference of display panel noise on touch signals.

Although full lamination technology has many advantages, its yield rate is relatively low, mainly due to the possible surface glass and panel loss during the lamination process. Therefore, controlling the defoaming and bonding yield has become the key to reducing costs.

In terms of full lamination technology, there are three main screen technologies: InCell, On Cell, and OGS. If frame pasting technology is used in the production process of mobile phone screens, it will seriously affect the display effect. And full lamination technology can significantly improve the yield rate, thereby reducing costs.



Different screen bonding technologies
In order to reduce the number of bonding cycles and improve the yield rate, several new development directions have emerged. Touch screen manufacturers mainly promote OGS/TOL solutions, while panel manufacturers are more inclined towards On Cell and In Cell technology solutions. These solutions can reduce the number of bonding times, save costs, and achieve the goal of lightweight.

In Cell technology is an innovative technique that embeds touch panel functionality into liquid crystal pixels. By embedding touch sensor functionality inside the display screen, the original three-layer structure (protective glass touch screen+display screen) has been optimized to two layers (protective glass+display screen with touch function), making the screen thinner and lighter. However, the research and development threshold for this technology is relatively high, mainly led by panel manufacturers.

Screen imaging principle
In the past, mobile phones had complex functions and rich details, but now, smartphones seem to be simplified into a single screen. We rely on this screen to operate and obtain information. The mobile phone screen displays colorful images through a combination of red, green, and blue pixels. With the development of technology, mobile phones are no longer limited to call functions, and the importance of screens has also become prominent. Whether watching videos, browsing pictures, or playing games, the screen carries the core content. Therefore, when choosing a smartphone, the screen often becomes an indispensable consideration for us.

However, are we really deep enough in our understanding of screens? When choosing a phone, we often only focus on screen size and resolution, but can these two really comprehensively measure the quality of the screen? In complex screen technology, which letter combinations truly reveal the material and panel technology of the screen? In fact, our misunderstanding of screens may be deeper than we imagine.

Unveiling the Technology and Principles of Mobile Screen

To present the text and images in our eyes, mobile phone screens rely on the three primary colors of red (R), green (G), and blue (B). Each pixel on the screen contains a complete RGB sub-pixel arrangement, and colors are recorded and expressed through RGB values. The RGB components of each pixel are within the intensity range of 0-255. It is through the different proportions of red, green, and blue that we can see a rich and colorful world.

Pixel, the color wizard of mobile phone screens

The colorful colors in our eyes are the clever combination of the three primary colors of red (R), green (G), and blue (B) on the screen. Each pixel contains a complete RGB sub-pixel arrangement, which creates a myriad of colors through different combinations of RGB values. Within the brightness range of 0-255, the proportional changes of the RGB three colors constitute the rich and colorful world in our eyes.



The comparison between 441ppi and 326ppi shows that the display effect of 441ppi on the left is more delicate and smooth.



After upgrading to 2K resolution, the screen's delicacy has reached a level that is difficult for the naked eye to distinguish. We have witnessed the continuous increase in screen resolution, which signifies that with the continuous advancement of technology, screens of the same size can now accommodate more pixels. By using PPI (pixel density) as an indicator, we can understand the number of pixels contained in each inch of the screen.

In the early days of the 1080p era of smartphones, we compared the screens of HTC Butterfly and iPhone 5, the world's first 1080p models. After capturing and zooming in on the screen with a macro lens, we found that the 441ppi HTC Butterfly surpassed the 326ppi iPhone 5 in terms of delicacy. This means that visually, the graininess on the screen is significantly reduced, and the overall display effect is more delicate and smooth. Nowadays, as mobile phone screens enter the 2K era, this level of delicacy has reached new heights, although it is still uncertain whether the naked eye can detect this change.

However, to comprehensively evaluate the quality of a mobile phone screen, relying solely on screen size and resolution is far from enough. These visible red, green, and blue small bright spots, also known as pixels, are undoubtedly the foundation, but they are only a part of screen display technology. The screen material and display technology also have a profound impact on the final visual effect.

LCD and OLED technology
In the current smartphone market, mainstream screen technologies can be divided into two categories: LCD and OLED.



LCD screens rely on backlighting during display, and light needs to pass through two layers of glass, a substrate, and various optical films, alignment films, color filters, and other components to produce polarization, which inevitably results in a loss of brightness and color. TFT, also known as thin-film transistor technology, is a key technology in LCD screens. It improves image quality by depositing a thin film as a channel area on a glass substrate.

In the TFT-LCD structure, the upper glass substrate is closely adjacent to the color filter, while the lower glass substrate is embedded with transistors. When current passes through a transistor, an electric field change is generated, causing liquid crystal molecules to deflect, thereby changing the polarization of light. Polarizers determine the brightness and darkness of pixels based on this polarity change. At the same time, the color filter attached to the upper layer of glass forms what we call RGB tri color pixels, which together constitute the colors and images displayed on the screen.



Subsequently, we will explore the types or panel technologies of LCD panels. LCD panels can be divided into two categories: simple matrix drive and active matrix drive. Among them, simple matrix driving mainly includes TN and STN technologies, while active matrix driving covers technologies such as TN, IPS, VA, and OCB. In the current smartphone market, TN and IPS technologies are more common, while VA technology is more commonly used in TV products.

TN screen, also known as Twisted Nematic (twisted nematic liquid crystal) screen, has been widely used since the emergence of liquid crystal technology and once dominated the field of electronic devices. However, nowadays many users mistakenly confuse TN screens with TFT screens, which is actually a misunderstanding of the two concepts. However, due to the mature production technology and affordable price of TN screens, they are still favored by some low-cost mobile phone brands. In addition, the high aperture ratio of TN screens makes them more energy-efficient compared to other technologies at the same brightness, and the response speed of 8-15ms is also quite fast. Therefore, although TN screens have shortcomings such as narrow viewing angles and color distortion, these advantages still make them occupy a place in the smartphone market.



IPS screen, also known as In Plane Switching (transverse electric field effect display technology), has significantly improved the color difference and narrow field of view problems of TN screens in poor viewing angles since its introduction in 1996 with its wide viewing angle technology. The electrodes of IPS liquid crystal are located in the same plane as the liquid crystal, thus achieving a wide viewing angle of 178 degrees up, down, left, and right. This breakthrough effectively overcomes the inherent defects of TN screens. However, IPS screens are not flawless. Despite its excellent viewing angle, it consumes relatively high power and has a slightly insufficient response speed, so it is necessary to weigh its pros and cons when using it.

Subsequently, in 1998, Hitachi launched an upgraded version of S-IPS (Super IPS), which not only inherited the original technological advantages of IPS, but also further optimized the response speed. In 1999, LG Philips joined the IPS camp as a joint venture, and after the bankruptcy of the joint venture in 2006, the IPS business was mainly taken over by LG Display and has continued to develop ever since.

Now, let's turn to OLED technology. OLED， The abbreviation for Organic Light Emitting Diode is different from TFT-LCD in that it has self luminescence and does not require backlight support. OLED technology has many advantages such as wide viewing angle, high contrast, low energy consumption, high reaction speed, full-color and simple process.



According to different driving methods, OLEDs can be divided into passive OLEDs (PMOLEDs) and active OLEDs (AMOLEDs). PMOLED and AMOLED are two different types. If OLED is compared to an upgraded version of LCD, then PMOLED is more similar to STN LCD, which has gradually withdrawn from the market. PMOLED performs poorly in displaying dynamic images and has a relatively slow response speed. Despite its power-saving features, it is limited in size. For smartphone users who pursue large screens and high-definition effects, PMOLED's 5-inch low resolution display is clearly not attractive enough to meet their needs. In addition, expanding the size of PMOLED will lead to an increase in pixel brightness and operating current, thereby shortening its lifespan.

Therefore, the vast majority of OLED screens we come into contact with today are AMOLED screens. AMOLED， Active matrix organic light-emitting diode, meaning active matrix organic light-emitting diode or active matrix organic light-emitting diode. The term 'AM' represents the pixel addressing technology behind it. This technology enables AMOLED to achieve low energy consumption and wide viewing angle display while maintaining high resolution and fast response, becoming one of the mainstream display technologies today. Not only smartphones, but also Samsung and LG's TV products use AMOLED screens, further proving their broad application prospects.

The core of AMOLED technology lies in its OLED matrix molecules, which can emit and store or integrate light into TFTs after electrical excitation. By precisely controlling the direction of current flowing to each pixel, AMOLED achieves high resolution and fast response. Each pixel is equipped with at least two TFTs to ensure stable control of continuous current. TFT backplane technology is crucial for AMOLED, and currently this technology has adopted two solutions: polycrystalline silicon and amorphous silicon.

The significant advantages of AMOLED include its self luminescence, wide viewing angle display, high contrast, and fast response time. In addition, compared to PMOLED, AMOLED also has a higher refresh rate, significantly reducing energy consumption. However, under direct sunlight, the reading effect of AMOLED may be affected to some extent. To improve this issue, Samsung has launched Super AMOLED technology, which enhances the display effect under strong light by reducing the screen spacing.

With the advancement of technology, Super AMOLED technology, as an upgraded version of MOLED, has the core improvement of reducing the screen spacing, which significantly improves the display effect in strong light environments. This technological innovation has significantly improved the outdoor reading experience of Super AMOLED, bringing consumers a more comfortable visual enjoyment.

First determine the type of fault

Fixed position color stripes/lines with broken inner screen, loose or aged wiring, lightly press screen edges for testing, backup data for repair

Full screen flashing/jumping stripe display driver failure, motherboard issue. Restart the phone to restore factory settings

Touch failure+striped touch screen damage or cable breakage, immediately stop using to avoid further damage

Possible self-study steps (at your own risk)

1. Eliminate software issues

Force restart of phone:

Huawei/Honor: Press and hold the power button for more than 10 seconds.

Xiaomi/Redmi: Power button+volume up button for 10 seconds.

IPhone: Quickly press Volume+, Volume -, and then long press the power button until the Apple logo appears.

Restore factory settings (data will be cleared):
Enter the system recovery mode (with different combinations of buttons for each brand) and select 'Clear Data'.



2. Check physical connections (for users with strong hands-on abilities only)

Disassemble the machine and re plug and unplug the ribbon cable (requires a screwdriver and pry bar):

After shutting down, remove the back cover (search for the corresponding disassembly video for the model).

Find the screen ribbon cable (usually located at the top of the motherboard), disconnect it, and then re fasten it.
⚠️ Risk: Improper operation may damage other components!

3. Temporary relief of display issues

Lightly press the edge of the screen: If the stripes change with pressing, it may be due to poor contact of the ribbon cable. You can try pressing the edge of the screen lightly for 12 hours (non permanent repair) with a book.

Do not attempt ineffective/dangerous operations

Heat the screen with a hair dryer (which may exacerbate delamination).

Freezing mobile phones (condensation water can corrode circuits).

Using the 'Screen Repair App' (purely false advertising, hardware issues cannot be fixed by software).

Ultimate solution official repair:

After sales replacement of screen assemblies for brands such as Huawei, Xiaomi, and Apple (priced at 300-1500 yuan, but with guaranteed quality).

Prioritize booking through official websites (such as Huawei services, Apple support).

Third party repair: Choose a store with good reputation and require the use of original or high imitation screens (lower price but higher risk).

Use a phone case and tempered glass film.

Avoid putting your phone under pressure (such as sitting in a pocket), high temperatures, or humid environments.

Regularly backup data to prevent sudden screen failure and data loss.

If the screen stripes are accompanied by touch failure or worsening diffusion, please stop using them immediately and send them for repair to avoid damaging the motherboard!

Why choose us? ‌As a globally leading one-stop wholesale service provider for mobile phone screens, batteries, and accessories, we boast 10 years of industry experience, dedicated to providing retailers, repair shops, and e-commerce platforms with high-quality, cost-effective mobile device accessories. Our core strengths include:
Certified factory direct supply: All products are produced by ISO-certified factories, ensuring quality control from the source.Authoritative quality inspection report: Each batch of screens has passed 20 rigorous tests including brightness, color, touch, etc., and provides a third-party inspection report, ensuring your procurement is worry-free.One-stop solution: Covering a full range of products including mobile phone screens, batteries, Flex Cables, Phone Housings, etc., supporting LOGO customization, OEM/ODM services, and meeting branding needs.Product highlight: Horizon series mobile phone screenFull type coverage: Mainstream screen technologies such as Incell, TFT, OLED, and Ori, compatible with models from brands like iPhone, Samsung, and Huawei.
Original-grade quality: The resolution and size are consistent with the genuine product, with a brightness of ≥400cd/m², a color reproduction rate of 98%, and having passed a 100% aging test.Customized Services: We support product packaging LOGO printing and Private Label, helping you create a unique brand image.Fast delivery: With ample inventory and support for DDP international logistics, we ensure global arrival within 7-15 days, reducing capital occupation.Core advantage: full-chain support from production to brandingOEM/ODM professional services:We offer OEM production of mobile phone screens and batteries, customizing parameters according to your specifications (such as size and interface).The ODM model supports the entire process from design to mass production, reducing your research and development costs.Private label and white label supply:We provide "white label" accessories for brand owners, without any brand identification, making it convenient for you to conduct private label sales.
Our private label service allows you to have your product packaging printed with your exclusive LOGO, enhancing market recognition.Win-win situation for quality and price:By reducing the unit price through large-scale production, we can offer a price 15%-30% lower than the market price, while ensuring no dark spots or liquid leakage.
We offer a 1-year warranty with an after-sales response time of no more than 24 hours.

Overview of Screen Materials


With the popularity of mobile phone color screens, the choice of screen material has become increasingly crucial. The differences in color screens of mobile phones mainly stem from differences in LCD quality and research and development technology, leading to the emergence of several major screen materials, including TFT, TFD, UFB, STN, and OLED. Usually, the more colors that can be displayed, the more complex images can be presented on the phone, and the levels of the screen are also richer.



TFT-LCD characteristics


TFT-LCD liquid crystal display screen, also known as thin-film transistor type liquid crystal display screen, is known as the "true color" display technology. Its uniqueness lies in equipping each pixel with a semiconductor switch, allowing each pixel to be directly controlled through point pulses, thereby achieving higher reaction speed and color accuracy. Therefore, TFT LCD displays not only have excellent brightness and high contrast, but also have a strong sense of hierarchy and bright colors. Despite its drawbacks of high power consumption and high cost, TFT LCD technology still drives the rapid development of mobile phone color screens. Nowadays, many new generation color screen phones support displays of up to 65536 colors or even 160000 colors, which undoubtedly demonstrates the significant advantages of TFT LCD in color richness and contrast.



IPS Technology Improvement


In addition, IPS technology is also worth mentioning. This technology is not a new screen material, but an improvement of LCD technology developed by Hitachi in Japan. By changing the arrangement of TFT liquid crystal molecules, IPS screens not only have a larger viewing angle, but also almost no ripples appear when pressed, resulting in higher color reproduction and more realistic images. It is worth mentioning that IPS displays perform well in handling highlight issues. After the transistor on a regular display screen burns out, it will produce bright spots, while IPS screens can transform it into dark spots without light, thus avoiding interference during viewing. Therefore, when choosing a screen, IPS screen is undoubtedly a recommended choice.



Advantages of AMOLED


AMOLED， Active Matrix/Organic Light Emitting Diode is an active matrix organic light-emitting diode that has the ability to emit light autonomously. It inherits many advantages of OLED, such as fast response, high contrast, wide viewing angle, and lightweight features. In addition, due to the inherent luminescence of AMOLED, its power consumption is only 60% of that of traditional screens, making it very suitable for use in mobile phone screens. When displaying dark colors, its luminous brightness is low, further saving energy.

At present, Samsung is a leading enterprise in AMOLED technology and holds the core technology. With numerous inherent advantages, AMOLED is expected to dominate the screen market in the future. However, due to production capacity limitations, Samsung is unable to meet the needs of all customers. For example, the iPhone 4 was originally planned to use an AMOLED screen, but ultimately switched to an IPS screen due to insufficient production capacity.



Enhancement of Super AMOLED


On the other hand, Super AMOLED, as an upgraded version of AMOLED, further optimizes the screen structure. It removes the touch sensitive panel in the middle and integrates touch functionality directly onto the AMOLED display layer, making touch more sensitive and color rendering more vibrant. In addition, the design of the native touch panel also improves the transparency of the screen, making the display effect more outstanding. Therefore, Super AMOLED surpasses traditional AMOLED screens in terms of touch sensitivity and display performance.



It is worth mentioning that Super AMOLED technology also incorporates two touch technologies, oncoll and incell. Among them, the oncell technology embeds the touch panel function between the color filter substrate and the polarizing plate, simplifying the production process. Although the production yield of incell technology still needs to be improved, its design concept of directly integrating touch panel functions into LCD pixels undoubtedly brings more possibilities for future screen technology.



Comparison of different materials


Compared with TFT screens, AMOLED has the characteristics of faster response speed, higher contrast, wider viewing angle, and thinner and lighter. In addition, due to the inherent luminescence of AMOLED screens, their power consumption is only 60% of that of TFT screens, making them very suitable for use in mobile phone screens. With the continuous maturity of AMOLED technology, we have reason to believe that it will be widely used in more mobile phones.



In the comparison of various screen materials, STN screen was the main component of early color screens, initially only able to display 256 colors. Although it can display 4096 or even 65536 colors after technological improvements, the common STN screens on the market still mainly use 256 colors. The advantages of STN screens are low cost and low energy consumption.



TFT screens are known for their excellent brightness, contrast, and layering, as well as vibrant colors, but their drawbacks are high power consumption and relatively high cost.



The UFB screen is designed specifically for mobile phones and PDAs, featuring ultra-thin and high brightness, capable of displaying 65536 colors, and a resolution of up to 128 × 160. Its special grating design reduces pixel spacing, thereby improving image quality. The UFB screen combines the advantages of STN and TFT, with lower power consumption than TFT and a price comparable to STN.