Under-Display Fingerprint Sensor Filling Structure for Signal Reliability
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Solution Overview
Problem
The reliability of fingerprint sensors in display devices is compromised by the attenuation of incident and reflected signals due to the presence of various members between the display panel and the fingerprint sensor, affecting the accuracy of fingerprint authentication.
Innovation Solution
Incorporating a filling member between the fingerprint sensor and the display panel to minimize signal attenuation by ensuring direct contact between the fingerprint ridges and the sensor, thereby enhancing signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple members are disposed between the display panel and the fingerprint sensor, then the display device can be assembled with various functional components, but the incident signal and reflected signal are attenuated, reducing fingerprint authentication reliability
Solution Approach 1:
The patent removes the lower polarizer from the display panel structure to eliminate the source of signal attenuation. By extracting this specific component that was causing the contradiction, the fingerprint sensor can receive stronger incident signals and detect reflected signals with higher reliability, while the display device retains its essential functionality through alternative optical compensation methods
Solution Approach 2:
The patent introduces a wavelength selective absorber as an intermediary component between the display panel and fingerprint sensor. This mediator selectively absorbs specific wavelengths of light that would otherwise cause interference and signal attenuation, allowing the fingerprint sensor to operate with improved reliability while maintaining compatibility with the display panel structure
2Ease of manufacture
If members are disposed between the display panel and the fingerprint sensor, then the display device structure can be completed, but the signal transmission is attenuated, affecting measurement precision
Solution Approach 1:
The patent extracts the lower polarizer from the display panel assembly to eliminate the primary source of signal attenuation. This extraction improves the optical transmission characteristics for the fingerprint sensor without significantly complicating the manufacturing process, as the removed component was part of the standard display panel structure
Solution Approach 2:
The patent changes the optical parameters of the display panel by removing the lower polarizer and introducing a wavelength selective absorber with specific spectral characteristics. These parameter changes optimize the light transmission properties in the fingerprint sensing wavelength range, thereby improving measurement precision while maintaining ease of manufacture through standard optical material substitutions
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Improves the reliability and accuracy of fingerprint authentication by reducing signal loss, ensuring consistent and reliable detection of fingerprint patterns.
Implementation Method 1
An incident signal emitted from the fingerprint sensor is reflected from the user's fingerprint and received back in the form of a reflected signal by the fingerprint sensor
Data Source
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AI summary
A display device includes a display panel, a metal plate disposed on a bottom surface of the display panel and configured to support the display panel, a filling member disposed on the bottom surface of the display panel, the filling member being disposed on the same level as the metal plate relative to the bottom surface of the display panel, and a material of the metal plate being different from a material of the filling member, a fingerprint sensor disposed on a bottom surface of the filling member, and a member-sensor bonding member disposed between the fingerprint sensor and the filling member to bond the fingerprint sensor to the filling member. A hardness of the filling member is greater than a hardness of the member-sensor bonding member.