Rollable Screen Craze

The Evolution of Smartphone Screens: A New Era

In 1973, Martin Cooper made the first call from a portable mobile device at Motorola’s laboratory in Manhattan, New York, marking the beginning of the consumer mobile communication era. Fast forward a few decades, and the phone has evolved from a simple communication tool to a multifunctional smart device that caters to entertainment, consumption, social interaction, and more. The phrase “phones glued to our hands” has become a common consensus for most people.

The transition of phones from communication tools to comprehensive smart devices is attributed to changes in the way we interact with them. The shift from physical buttons to touch and swipe gestures has opened up more innovative possibilities for developers and users. When we talk about changes in interaction, the screen plays a pivotal role: on one hand, it is responsible for core content output as over 90% of human information is visual; on the other hand, the touch screen has long replaced the keyboard as the primary input medium. It can be said that the screen handles the majority of the phone’s input/output functions. The main theme of screen evolution largely revolves around advancements in display technology.

From the revolution of Retina LCD to the leap to high-end OLED

The groundbreaking moment when the iPhone changed the world lay in the upgrade of its screen: the touch screen replaced physical keyboards and stylus pens, refreshing the human-machine interaction model. Simultaneously, the high definition of the “Retina display” transformed the display quality of phone screens significantly.


(Image Source: Cellular Sale)

Retina LCD touch screens are not the starting point nor the end goal of phone screen upgrades.

In 2017, Apple, a long-time user of LCD screens, integrated OLED screens into its “next-generation” product, the iPhone X. Subsequently, OLED became a coveted feature in the smartphone market. With its flexibility and superior display quality, OLED quickly became a standard feature in flagship models. At that time, OLED displays were already popular in smart TVs and other devices, with the technology maturing and costs becoming more affordable.

Apart from Apple, leading Android phone manufacturers also embraced OLED screens. Over the past few years, high-quality OLED display panels have transitioned from flagship to mid-range markets, allowing more consumers to experience a completely different visual experience.

Recently, Honor unveiled the world’s first smartphone with a dual-layer series-connected OLED display at its flagship launch event – the Honor Magic6 RSR Porsche Design edition. Its exceptionally high brightness and extended lifespan left a lasting impression on users. During this event, Leitech personally experienced this innovation and concluded that the next era of smartphone screens has arrived.

As mobile product forms mature, most manufacturers face the dilemma of innovation saturation. By 2024, AI became the new focus for phone manufacturers. Meanwhile, key functions like imaging, screens, materials, communications, batteries, and charging continue to show diverse innovative trends (Leitech has extensively reported, reviewed, and analyzed systems focused on AI hard technology). Screens have now become a crucial focal point for competition.

Pushing brightness to the limit: There’s no brightest, only brighter

OLED panels offer higher brightness, contrast, and better color presentation, which are enormous advantages for small mobile devices such as smartphones and smartwatches. Among these features, brightness is one of the most crucial parameters for screens and has become a focal point for phone manufacturers.


(Image Source: Xiaomi)

In January 2023, Samsung showcased a new small-sized OLED display with a peak brightness of 2000 nits, setting a new industry record at the time. This record has been continually broken over the past year, with the Xiaomi 14 series featuring Huaxing Optoelectronics’ C8 luminescent material hitting a peak brightness of 3000 nits, and the OnePlus 12 equipped with the “Oriental Screen” jointly customized with BOE, achieving a sensational 4500 nits of peak brightness.


(Image Source: OnePlus)

In Leitech’s perspective, enhancing brightness in OLED panels is the right direction. On one hand, smartphones have become indispensable in our lives, implying increased usage in high-light environments. Super high peak brightness resolves the issue of phones being difficult to read in such scenarios. On the other hand, with more platforms supporting HDR content, the viewing experience on smartphones with matching brightness for HDR content has become crucial, enhancing the user experience.

Recently, Realme held an online media briefing, inviting Leitech to witness the arrival of a new generation of unparalleled screens. This screen boasts a partial peak brightness exceeding 6000 nits, with intense light peak brightness reaching 1600 nits, maintaining above 1000 nits even with manual activation.


(Image Source: Realme)

We have every reason to believe that Realme’s new generation of unparalleled screens is not the limit to the “brightness roll” of OLED panels. More new technologies might arrive later this year, including double-layer series-connected OLED technology. **

The dual-layer series-connected OLED technology first debuted on the Porsche Design version of Magic6 RSR by Honor is essentially stacking multiple traditional OLED devices in series through a connecting layer to achieve higher brightness and better display performance. In addition, the biggest advantage of dual-layer series-connected OLED is that it manages to keep power consumption below 30% while doubling the brightness, resulting in longer brightness activation time.

(Source: Honor)

With higher brightness, lower power consumption, and longer lifespan, it is hard to imagine dual-layer series-connected OLED technology not becoming a guiding light in the smartphone market. It is reported that Samsung has also made advancements in dual-layer series-connected OLED technology and is expected to collaborate with Apple to debut screens utilizing this technology on the next generation iPad Pro, enhancing the market acceptance of OLED panels for iPad Pro as they transition from LED.

(Source: Digital Trends)

In addition to dual-layer series-connected OLED technology, Samsung is planning to shift its QD-OLED production line towards the field of small to medium-sized panels. According to South Korean media outlet KIPOST, Samsung Display has currently halted investments in large-sized QD-OLED panels (TVs, professional displays) and is turning towards the small to medium-sized market (phones, PCs), potentially unveiling corresponding display solutions in the near future. Compared to traditional OLED panels, QD-OLED panels offer higher brightness, longer lifespan, and superior color accuracy.

Of course, for an excellent screen, brightness is just one important indicator among others like contrast, color performance, refresh rate, and eye protection effects, with refresh rate being one of the focus areas within smartphone screen technology nowadays.

Elevating refresh rates to “trick” the human eye

In 2017, Sharp released the first 120Hz refresh rate smartphone AQUOS R, making “high refresh rate” a standard feature for smartphones, and for a period, it became one of the most fiercely contested hardware specifications among manufacturers. Initially starting from 90Hz, progressing to 120Hz, then 144Hz, and even reaching 240Hz comparable to PC gaming screens. However, consumers began to notice that higher refresh rates led to increased power consumption, which was deemed unacceptable.

To meet the consumer demand for a balance between experience and power efficiency, panel semiconductor manufacturers began applying LPTO technology in the smartphone domain. This technology offers different refresh rates for various scenarios, allowing phones to switch between them to save power.

Today, apart from the standard iPhone models, screens supporting high refresh rate technology have appeared in smartphones across various price points. Even budget phones like Redmi 13C, priced at 699 RMB, already feature a 90Hz screen. But in reality, the journey towards higher refresh rates is far from over.

(Source: Xiaomi)

The Xiaomi 14 Ultra launched a C8 display panel jointly customized with Huaxing Optoelectronics, which leads the industry in color depth, brightness, and eye protection effects. What’s more surprising is that this screen goes a step further in LTPO technology, supporting a wider range of variable refresh rates. LTPO technology combines LTPS and IGZO in the driving circuit, enabling the screen to automatically switch between multiple refresh rates as needed for power efficiency.

Typically, due to the complex structure of LTPO components, most manufacturers offer only a few levels of variation. For instance, the iPhone Pro series provides 13 levels from 1Hz to 120Hz, where the screen adjusts the refresh rate based on the user’s finger movements.

While covering a wide range of rates, the transition between different refresh rates can still be perceptible to keen users, causing slight stutters during screen swiping due to varying touch response speeds. Xiaomi 14 Ultra offers a richer variety of rate switches on its screen, alleviating visual and tactile lags, enhancing overall smoothness.

Currently, most customized systems provide ample animated transitions. However, even with refined interruptions like those in Honor’s MagicOS 8.0, the adaptive refresh rates continue to challenge seamless user experiences. With Xiaomi 14 Ultra leading the market in this technology, more manufacturers are expected to follow suit, aiming for “infinite high refresh rates” to further enhance visual and tactile experiences for users.

As screens improve, phones become more powerful, users depend on them increasingly. How to protect users’ eyes has become a new issue for more manufacturers to ponder and solve. Thus, “eye protection” has become another direction for upgrading smartphone screens.

Embracing digital wellness, screen eye protection enters the AI era

Due to LCD panels utilizing DC dimming, inherently causing less eye strain compared to OLED panels, this explains why there is still significant demand for LCD panel smartphones despite OLED’s advantages.

Over the past two years, nearly every manufacturer has emphasized “eye protection” as a key feature, such as Honor’s Oasis Screen and OnePlus’s Vision Guard technology. ** ## Understanding OLED Panel Dimming Technologies

In essence, there are three main types of dimming technologies for OLED panels: high-frequency PWM dimming, DC-like dimming, and low-frequency PWM. Manufacturers’ “eye protection technology” involves a reasonable combination of these three dimming technologies to achieve better results.

(Image Source: Xiaomi)

High-frequency PWM dimming is a focal point for eye protection that various smartphone manufacturers are focusing on. For instance, Xiaomi’s Qing Shan eye protection technology features high-frequency dimming up to 3840Hz, while Honor’s Green Oasis eye protection screen raises the frequency to 4320Hz. Generally, it is widely accepted in the industry that the critical value of high-frequency PWM dimming is around 1250Hz. Once this value is exceeded, the eye protection effect can be considered satisfactory.

However, high-frequency PWM dimming requires relatively complex hardware conditions and algorithms, leading to higher costs compared to ordinary dimming technologies. This is why initially only some flagship models could incorporate this technology. Recently, smartphones like OnePlus Ace 3V and the upcoming Realme Neo 6 series have implemented the latest eye protection technologies, indicating that “eye protection” is poised to become one of the mainstream elements in future screen technologies.

(Image Source: OnePlus official website)

As mentioned earlier, a mixed solution for dimming technology is currently considered a compromise to cater to different brightness scenarios for smartphones. However, customizing a reasonable mixed mode is a significant challenge for manufacturers. For example, Xiaomi’s Redmi K70 series features an all-scenario AI dimming strategy that uses AI to adjust the most suitable dimming strategy for various scenarios. On the other hand, Realme delegates some tasks to AI large models to make decisions, with its “Greenfield AI Eye Protection” system intelligently determining eye protection based on user fatigue, physical condition, and usage scenario.

Over the past year, AI large models have been widely utilized in smartphones, such as Xiaomi’s collaboration with imaging, Honor’s partnership with smart interconnection, and OPPO/vivo’s intelligent assistant, leading to the development of interesting functionalities like AIGC elimination. With the advancement of large model technology, AI is set to penetrate various specific areas on smartphones. Just as Xiaomi and Realme have integrated AI with dimming algorithms, this integration is expected to be a new trend in the future.

Smartphone’s Craze for “Rollable” Screens to Satisfy Visual “Cravings”

From traditional mobile phones to smartphones, we are heavily reliant on these handheld devices in various aspects of life. With the arrival of foldable screen phones that redefine the mode of “mobile office” and AI large models making smartphones the most efficient assistants, the significance of smartphones has been magnified infinitely.

This brings us to a vital point of concern: smartphone addiction.

According to a report by Market Research Firm Election Hub, the Philippines ranks highest in smartphone addiction globally, with individuals spending approximately 32.53% of their day staring at the screen. Meanwhile, China leads the world in average smartphone usage, with individuals spending 19.54% of their day using smartphones for life and work tasks.

This implies that we spend nearly 5 hours a day in front of screens. Poor screen quality, such as flickering and blue light issues, can easily trigger eye diseases and cause irreversible harm.

(Image Source: Honor)

It must be acknowledged that “rollable” screens are one of the most challenging solutions for smartphone manufacturers. Unlike cameras that allow users to feel the difference instantly in experience when trying in a store, or heavy-hitting performance and heat dissipation to provide a smooth experience in benchmarks and mobile games, the quality of a smartphone significantly influences consumer desire. This perhaps clarifies why smartphone manufacturers are enthusiastic about “rollable” screen technology.

(Image Source: OPPO official website)

Furthermore, as camera technology continues to advance on smartphones, screen quality naturally needs to be upgraded in tandem. Taking OPPO as an example, as early as 2023, the OPPO Find X6 series introduced ProXDR technology, which fully records the on-site lighting scenes and light and dark information when shooting HDR content on the phone, and then displays it using HDR technology on the screen. ProXDR has now shown a trend towards downward accessibility, with the recent release of the budget-friendly OnePlus Ace 3V also supporting this feature.

(Image Source: Xiaomi)

In addition to HDR support brought by high brightness, professional-grade original color displays on screen panels are a key direction for improving screen quality. Xiaomi’s Mi 14 Ultra, which debuted “Master Portrait” and “AISP,” supports professional original color displays on its Huaxing Optoelectronics C8 panel. This not only helps in better color reproduction of photos but also reduces the color difference between it and professional monitors, gaining recognition for the image capabilities of smartphones among professionals.
Therefore, the concept of “curved” screens is not merely about competing on specifications, but it progresses in line with the real needs of consumers and the enhancement of other features in smartphones. Whether it’s the users themselves or the smartphone manufacturers, they are beneficiaries of these new technologies.

To what extent should smartphone screens be “curved” to reach market saturation? According to Ray Technology, this question may not have a definite answer.

Firstly, in terms of display technology, new technologies such as Mini LED, Micro LED, AI display, etc., continue to refresh display quality. In due course, when these technologies mature, smartphones will continue to see screen innovations.

Secondly, how to achieve “compact size, large display” for screens? Users demand both large screens and portability. Display technologies like “foldable screens” and “holographic projection screens” are highly anticipated, as people need more and better display expansion solutions.

Finally, beyond flat displays, the wave of spatial computing stirred by devices like Vision Pro necessitates new types of display solutions that can blend the real world with the virtual world. The essence of XR (Extended Reality) is to revolutionize display and human-computer interaction modes. Thus, 3D spatial display will also be a crucial direction for future smartphone screen upgrades.

Human beings have an insatiable appetite for vision. As long as electronic product screens cannot match the real world 100% (including high definition, color, realism, brightness, and health), there will still be a demand for screen technology upgrades. The upgrade of smartphone screens is an ongoing process, with no endpoint in sight.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.