In-display optical fingerprint sensor: what it is, how it works and what it does
A biometric component that uses light to capture fingerprint images through the device's display.
Definition and Principles
The in-display optical fingerprint sensor is a biometric component integrated into the display surface of an electronic device. Unlike capacitive or ultrasonic sensors, this technology is specifically classified as optical. Its operation is based on emitting light (typically LED) through the screen to illuminate the user's fingertip. A camera or image sensor located beneath the screen captures the reflected light, generating a digital image of the fingerprint's ridges and valleys.
Architecture and Operation
The architecture of this component requires the screen to allow light to pass through without significantly degrading the quality of the captured image. The process follows these steps:
- Light Emission: The sensor activates a light source that passes through the display panel.
- Reflection: The light hits the finger's skin and reflects differently depending on the fingerprint's topography (ridges reflect more light than valleys).
- Capture: The optical sensor records the pattern of reflected light.
- Processing: The system converts the image into a digital map for comparison with stored templates.
Applications and Scope
This component is primarily used in smartphones and tablets for biometric authentication. Its presence allows unlocking the device, authorizing payments, or accessing protected applications without the need for a dedicated physical button, optimizing the device's front design.
Limitations
As an optical technology, its performance can be affected by external factors such as dirt on the screen, moisture on the fingers, or intense ambient light, which can interfere with the clarity of the captured image.
Interpretation in Products
Specifying a fingerprint sensor as optical and in-display indicates that the device employs this specific methodology for biometric security. The confirmation of the presence of a fingerprint scanner (Fingerprint's scanner = Yes) along with the type definition (Type: in-display (optical)) allows for the precise identification of the authentication technology implemented in the product.