The difference between the two



1. Thickness: LCD screens are thick and hard, and cannot be bent; OLED screens can be bent, making them softer and thinner. From a structural perspective, AMOLED thickness can be nearly 30% thinner than LCD.





2. Price: Due to the mature technology of LCD, LCD is cheaper in terms of price.



3. Service life: LCD screens use inorganic materials, while OLED screens use organic materials. OLED screens have a shorter service life than LCD screens.



4. Color expression: LCD emits light through backlight refraction, so when displaying black, there may be light leakage and whitening around the screen, making black more similar to gray. OLED can express colors through self emission, resulting in a more vivid and full display effect, but there is a risk of screen burn-in.

(Representation of Black)



5. Energy consumption: The luminous principle of LCD is that the color filter film will cause a decrease in light efficiency. Some analyses suggest that the utilization rate of LCD for backlight brightness will not exceed 15%, and 85% of energy is wasted. Therefore, OLED is more energy-efficient than LCD.



LCD is never a slave



OLED screens are often referred to as "blind screens" due to the issue of screen flicker. When adjusting screen brightness, OLED screens use PWM dimming, which is commonly understood as turning on and off every second to control brightness. The brightness is adjusted by the proportion of screen on/off time within the interval.



As long as I light up and turn off quickly enough, my brain cannot feel that I am rapidly switching between light and light states. For some people who are sensitive to screen flicker, PWM dimming is particularly unfriendly to their eyes at low brightness, especially at night, which is why some people may feel obvious eye pain and soreness when using their phones at night.



However, many manufacturers later introduced DC modulation to solve the problem of screen flicker, but with it came the problems of screen burn-in and uneven brightness.



LCD enthusiasts are shouting: LCD will never be enslaved, because of the fatal problem of OLED screen flicker.

(Screen flicker display under camera, image sourced from the internet)



future trends



Although OLED has screen flicker issues, in daily use, the human eye cannot clearly perceive it. Only those who are very sensitive to screen flicker will truly feel discomfort.



OLED with greater power than excess has more advantages, such as better contrast, better black performance, wider color gamut, lighter, thinner, bendable, and so on. That's why mainstream flagship phones now choose OLED screens.

In the future, the development trend of mobile phones will also move towards full screen, curved/foldable screens, and under screen fingerprint and under screen cameras, and the position of OLED will not be shaken. LCD screens will be more commonly used in mid to low end smartphones due to their low cost and mature technology.



So, whether to choose LCD screen or OLED screen, Haoge has summarized their respective advantages and disadvantages for everyone. If you are particularly sensitive to screen flicker, it is recommended to choose LCD. In addition, choosing OLED screen can bring a better visual experience.

Comparison of Three Packaging Technologies


1. COG (Chip On Glass): This is one of the most traditional packaging methods, with low technical barriers and low costs, and is the most commonly used technology for screens. From the English version, it can also be seen that this packaging method involves placing IC chips and FPC cables on the back glass of the screen. However, due to the IC chip being located directly below the LCD, a considerable amount of screen space is squeezed, inevitably resulting in a "chin".




2. COF (Chip On Film): Essentially, it is an upgraded version of COG and a key factor in the current screen transformation. The main principle is to place the display driver IC chip into a flexible FPC cable, and then fold it under the screen using the characteristics of the FPC itself. Specifically, through hot pressing, the Gold Bump of the IC chip and the Inner Lead on the flexible substrate circuit will be bonded together. Due to the release of space occupied by IC chips, the lower frame width can generally be reduced by at least 1.5 millimeters.






3. COP (Chip On Pi): It belongs to the process with the most reduced borders, but it should be emphasized that the premise of this process is the application of flexible OLED screens, which utilize the bending characteristics of flexible OLEDs to bend all cables and ICs below the screen. Of course, OLED is also divided into two types: hard screens and flexible screens. To use this technology, a combination of COP packaging technology and flexible OLED must be used. However, this technology still has the disadvantages of high cost and low yield rate.





After introducing the technical foundations of COG, COF, and COP, let's take a look at the practical application of COP technology on Samsung S8. This phone adopts innovative COP screen packaging technology, which allows the screen edges to bend without physical limitations, achieving a nearly borderless visual effect. This technology not only enhances the aesthetic appearance of mobile phones, but also brings them a wider display space.

The performance of the Chinese market is particularly outstanding. Starting from 2023, the Chinese market will surpass other markets and become the world's largest foldable screen mobile phone market. IDC predicts that in the next five years, the proportion of the Chinese market in the global foldable screen mobile phone market will remain stable at over 40%.

Specifically, in the first half of this year, the shipment volume of foldable screen smartphones in the Chinese market reached 4.98 million units, a year-on-year increase of 12.6%. Among them, Huawei's performance is particularly prominent, occupying 75% of the Chinese market share with a record high of 3.74 million units.

Specifically, in the first quarter of 2025, Huawei shipped 2.84 million units, accounting for approximately 76.6% of the market share; Following closely behind are brands such as Honor and OPPO, but far behind Huawei. Although there was a slight decline in the second quarter, Huawei still maintained its dominant position with a market share of 72.6%.

IDC pointed out that Chinese manufacturers are generally leading the global popularization of foldable screen technology by relying on mature local supply chains, high user acceptance, and precise market strategies. Huawei not only successfully boosted sales, but also promoted the localization of materials and core components in the industrial chain, further enhancing China's independent and controllable capabilities in this field.

Of course, the most significant feeling for consumers is that the current foldable screen prices are becoming increasingly affordable. In fact, this is also the result of the continuous expansion of the market and the continuous decline of supply chain costs. And more affordable prices can further drive market growth, thereby driving down the prices of foldable phones and gradually replacing conventional phones. So the question is, have you used a foldable phone yet?

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.