fingerprint sensor in display
A fingerprint sensor in the display, also known as an in-display fingerprint sensor, is a biometric authentication technology that allows users to unlock their devices or authenticate transactions by placing their finger on the device's display. This technology has become increasingly popular in smartphones as it offers a seamless and convenient way to secure devices without the need for a physical fingerprint sensor on the front or back of the device.
Here is a technical explanation of how an in-display fingerprint sensor works:
- Sensor Types:
- Optical Sensors: Most in-display fingerprint sensors are optical sensors. These sensors use light to capture an image of the fingerprint when the user places their finger on the designated area of the screen.
- Ultrasonic Sensors: Another type of in-display fingerprint sensor uses ultrasonic waves to create a 3D map of the fingerprint. Ultrasonic sensors are less affected by environmental conditions such as dirt, oil, or water on the finger.
- Sensor Placement:
- The fingerprint sensor is embedded beneath the device's display. This requires the use of special materials that allow light or ultrasonic waves to pass through, ensuring that the sensor can capture an accurate image of the fingerprint.
- Illumination (Optical Sensors):
- In the case of optical sensors, a light source (usually an LED) illuminates the user's finger. The light passes through the display and reflects off the ridges and valleys of the fingerprint.
- Image Capture (Optical Sensors):
- A photosensitive sensor beneath the display captures the reflected light and generates an optical image of the fingerprint. This image is then processed by the device's software.
- Ultrasonic Mapping (Ultrasonic Sensors):
- In the case of ultrasonic sensors, the sensor emits ultrasonic waves through the display. These waves penetrate the outer layer of the skin and bounce back to the sensor, creating a detailed 3D map of the fingerprint.
- Image Processing:
- The captured fingerprint image or 3D map is processed by the device's software using advanced algorithms. The software analyzes the unique features of the fingerprint, such as ridge patterns, bifurcations, and minutiae points.
- Fingerprint Matching:
- The processed fingerprint data is compared to the stored fingerprint template on the device. If there is a match, the device grants access or authenticates the user.
- Security Measures:
- In-display fingerprint sensors often incorporate additional security measures to prevent unauthorized access. These may include anti-spoofing technologies to detect fake fingerprints, liveness detection to ensure that the fingerprint is from a living person, and encryption to protect the stored fingerprint data.
- Integration Challenges:
- Implementing in-display fingerprint sensors presents challenges related to display technology, material transparency, and sensor performance. Manufacturers need to optimize the integration to maintain display quality and ensure reliable and fast fingerprint recognition.
An in-display fingerprint sensor combines hardware (optical or ultrasonic sensor), software (algorithms for image processing and fingerprint matching), and design considerations to provide a secure and convenient biometric authentication method for users.