Which is More Advanced: Optical or Ultrasonic Fingerprint Sensor Technology?

Optical fingerprint sensors, also known as fingerprint scanners, rely on light emitted from the screen to capture fingerprints. Utilizing highly sensitive scanners with integrated lenses and OLED screens, these sensors enable each pixel on the screen to emit independent light.

An essential aspect of optical fingerprint sensors is the requirement for OLED screens. Independent light emission from pixels allows direct illumination of fingerprints. The reflected signals are then captured by the sensor and analyzed by the integrated processor. High-end devices often adopt this technology, whereas those with LCD screens cannot support it.

While considered relatively secure, the security of optical sensors lags behind traditional and ultrasonic fingerprint technologies. The reflected 2D images from the light are processed through an internal chip, and algorithms convert them into encrypted forms for user identification.

Algorithms within optical fingerprint sensors typically originate from the main component manufacturers. Companies like Xiaomi, OPPO, and vivo commonly use Synaptics fingerprint sensors. Beyond manufacturing, Synaptics also provides fingerprint recognition algorithms to its partners.

When you place your fingerprint on the fingerprint sensor to unlock, the device repeats the registration process to check if the raised and recessed parameters of the fingerprint match. A deviation of less than 10% ensures quick and convenient usage.

A drawback of optical fingerprint sensors is the screen's bright illumination in the sensor area during usage. This can be somewhat uncomfortable for nighttime usage. To address this, manufacturers often add interesting animations to enhance liveliness and make users feel more comfortable.

Operating Principle of Ultrasonic Fingerprint Sensor

Ultrasonic fingerprint sensors seem to be a technological leap beyond optical sensors. In theory, this technology uses ultrasonic waves to analyze fingerprints in more detail, with algorithms providing clear analysis and storage.

Fundamentally, the components of ultrasonic fingerprint sensors do not differ much from optical sensors. In addition to the fingerprint scanner, an ultrasonic emitter is added below to emit ultrasonic waves instead of light from the phone screen. With this fingerprint sensor, you won't experience the screen's bright glow at night, reducing discomfort and eye strain.

Moreover, ultrasonic fingerprint scanners hold an edge thanks to ultrasonic waves providing better signal feedback intensity. This results in the collection of a more substantial amount of fingerprint-reflected data, ensuring higher accuracy and lower error rates compared to optical fingerprint sensors using screen illumination.

Ultrasonic fingerprint sensor modules come with a relatively high price tag, and currently, very few manufacturers equip this type of fingerprint sensor in their products. Except for Samsung, the brand that has actively worked on and integrated ultrasonic fingerprint sensors since the Galaxy S10 series introduced in 2018.

So, which technology is superior?

Honestly speaking, from a basic user perspective, you won't be able to discern clear differences or determine which one is significantly better, even when using a variety of devices equipped with these technologies from different brands. Simply because current on-screen fingerprint sensors have undergone significant improvements, making errors very rare.

For my personal experience, the optical fingerprint sensor provides a quick and convenient experience, even when using a relatively thick screen protector. On the OnePlus 10 Pro, I noticed rapid recognition and fast unlocking times, taking only about 1-2 seconds to access the main screen.

For users of older phone generations, unlocking may require a bit of patience and tapping on the screen. In contrast, newer generations have improved the under-display area for a quicker, gentle touch unlock experience, minimizing eye glare. Adjusting the fingerprint sensor brightness is not possible, so users must accept this limitation when using optical fingerprint sensors.

As for ultrasonic fingerprint sensors, this modern technology provides a remarkably fast speed. Unlocking the screen with ultrasonic waves is even faster than optical fingerprint sensors, taking less than 1 second. This is a personal estimate based on my experience with .

Eye glare or discomfort will never occur as the ultrasonic scanning system doesn't require any supporting light. So, if you use your phone extensively in the dark, you'll find it much more comfortable than optical fingerprint sensors. However, there are limitations when applying screen protectors as ultrasonic waves may be obstructed by thick tempered glass.

Additionally, the ultrasonic fingerprint sensor, by collecting detailed information about fingerprint ridges and valleys, enhances security and unlocks faster. This is especially true when fingers are wet or sweaty, as it won't impede fingerprint recognition like optical fingerprint technology.

A significant drawback of the ultrasonic fingerprint sensor is its high cost, making the overall product price more expensive compared to other brands. For instance, Samsung integrated ultrasonic fingerprint sensors for the entire Galaxy S2 lineup, but excluded this feature in the Galaxy S20 FE.

In summary

In essence, it's challenging to compare the unlocking speed of optical fingerprint sensors and ultrasonic fingerprint sensors at the current moment. Additionally, users cannot choose their preferred technology; it entirely depends on what the manufacturer equips for that specific model. The only choice you have is your preference for a particular brand. In a thorough comparison, ultrasonic fingerprint technology will perform better when your hands are dirty. Meanwhile, optical fingerprint sensors have the advantage of penetrating through screen protectors effectively.

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