When you pick up an iPhone, the black pill-shaped cutout at the top of the screen is always there.

From the notch on the iPhone X to the Dynamic Island on the iPhone 14 Pro, Apple has spent nearly a decade trying—and failing—to fully hide the Face ID sensors.

In October 2026, the iPhone 18 Pro series, for the first time, embedded the infrared flood illuminator beneath the screen.

The width of the Dynamic Island has been reduced from 20.76mm to approximately 16.57mm, shrinking its area by about 20% and increasing the screen-to-body ratio to 94.7%.

But here's the question: Face ID relies on infrared light, which can't penetrate the screen. How did Apple pull it off?

01

Infrared Light Can't Penetrate the Screen?

Make a Path for It

The TrueDepth module for Face ID needs to emit and receive infrared light simultaneously. It projects over 30,000 invisible infrared dots onto the user's face to create a 3D depth map for identification.

However, the pixel arrangement in conventional OLED screens is too dense for infrared light to penetrate the pixel layer.

Apple's solution comes in three steps. The first step is to make room for the pixels.

Apple redesigned the pixel arrangement in the under-display Face ID area, intentionally leaving larger physical gaps between pixels to allow infrared light to pass through the gap (gaps).

The trade-off is that the pixel density in this area has dropped by about 50%, a figure confirmed by Apple.

The second step is to compensate for the brightness.

With half the pixels gone, the display brightness would be uneven, appearing as a dark spot in the middle of the screen.

Apple simultaneously increased the luminance of the remaining pixels in this area, ensuring that the perceived brightness matches the surrounding regions.

The third step is to install a one-way door. A dedicated infrared filter layer has been added inside the screen.

This filter acts like a one-way door, allowing only infrared light to pass through while blocking visible light from leaking through the pixel gaps, further concealing the sensor components below.

The result of these three engineering layers is that, during everyday use, the under-display Face ID module is nearly undetectable even when observing the screen up close.

Image Source: Internet

Only under microscope-level magnification can the special pixel arrangement in this area be observed.

It should be noted that Apple has only placed the infrared flood illuminator beneath the screen this time, while the front camera, dot projector, and infrared camera remain in the Dynamic Island.

This is a partial under-display implementation, not a complete hiding of the entire Face ID module.

02

The Dynamic Island Shrinks

But Holds More Information

The most immediate impact of this technology is a significant increase in usable space within the Dynamic Island.

The iPhone 18 Pro's Dynamic Island can now display up to three real-time activities simultaneously, compared to just two in the previous generation.

This means navigation, music playback, food delivery tracking, and timers can all appear on the Dynamic Island at the same time, without needing to crowd out (crowd out) or take turns displaying.

In video playback and fullscreen gaming scenarios, a smaller Dynamic Island means a more complete picture.

The black area at the top has narrowed by about 20%, so fullscreen content is no longer obstructed.

Image Source: Internet

But Apple's ambitions don't stop there. According to its long-term design roadmap, the goal is to eventually move the front camera beneath the screen as well, achieving a truly hole-free front design.

The under-display Face ID on the iPhone 18 Pro is the first mass-produced implementation on this technical path.

03

Why Didn't Android Do It First?

The technical difficulty of under-display Face ID is far greater than that of under-display fingerprint or under-display camera.

Under-display fingerprint only needs to recognize a two-dimensional fingerprint pattern, while under-display camera only needs to let light pass through the screen to reach the sensor.

Face ID, however, needs to project and receive tens of thousands of infrared dots to construct a 3D depth map. The infrared light must pass through and return, requiring signal quality and precision several orders of magnitude higher.

Cost is another barrier. The Face ID module itself includes multiple precision components such as a VCSEL laser, infrared camera, and flood illuminator, with a per-module cost about 2-3 times that of under-display fingerprint.

Add in the fact that custom high-transmittance OLED screens cost over 30% more than regular screens, and the BOM cost for the entire solution soars.

Another often-overlooked reason is that most Android flagships have already shifted to ultrasonic under-display fingerprint, reducing the priority for 3D facial recognition.

Image Source: Internet

The Pixel 4 previously attempted 3D facial recognition but abandoned it after just one generation, citing reasons including the aesthetic compromise of a large forehead design and excessively high component procurement costs. Since Pixel 4 sales were far lower than iPhones, it couldn't amortize these costs.

Apple ships around 200 million units annually, so any yield issues with new processes are magnified.

The current mass-production light transmittance for consumer-grade AMOLED under-display infrared cameras hovers between 65-70% at the industry's top level, while Apple has set a Qualified (qualified) transmittance threshold of ≥80% for the Face ID infrared imaging module. This gap isn't just a few points—it's a physical bottleneck that any full under-display solution must overcome.

Meanwhile, Apple maintains equally stringent yield requirements for screen panels, setting the LTPO+ panel yield threshold at over 85%. This directly caused suppliers with yields of only 65-70% to lose orders.

This means Apple only implemented partial under-display Face ID components on the iPhone 18 Pro, not the entire module. It retained some cutouts, planning to gradually expand under-display implementation as transmittance and yields improve.

04

Final Thoughts

From the notch on the iPhone X to the Dynamic Island on the iPhone 14 Pro, and now to the shrunk Dynamic Island on the iPhone 18 Pro, Apple has spent nine years transforming a screen that once had a chunk cut out into one where the cutout is nearly invisible.

The mass production of under-display Face ID means the design vision of a single, unbroken glass surface has transitioned from concept to engineering reality.

Another change is the evolving functional role of the Dynamic Island.

As it shrinks but can now carry three real-time activities simultaneously, its role has shifted from a cosmetic cover-up for cutouts to an information hub at the top of the screen.

Navigation prompts, food delivery progress, music controls, timers—information you can see without opening an app—is redefining the purpose of that small area at the top of your phone screen. #Apple18 #DynamicIsland