Non-uniform Insulating Layer for High-Resolution Fingerprint Sensing
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Solution Overview
Problem
Current display devices face challenges in achieving high-resolution biometric information sensing, particularly in reducing the effective fingerprint area to match the pitch of fingerprints, which affects the accuracy and reliability of fingerprint recognition.
Innovation Solution
The display device incorporates a specific design with a base layer, light emitting elements, optical sensing elements, a thin film encapsulation layer, an insulating layer, and a light blocking pattern, where the insulating layer has a thickness greater than the insulating layer itself, and the light blocking pattern includes openings corresponding to the light emitting and optical sensing elements, optimizing the effective fingerprint area and enhancing sensing resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the effective fingerprint area is reduced to match the pitch of fingerprints, then the resolution of sensed fingerprints is improved, but the sensing area is reduced
Solution Approach 1:
The insulating layer is designed with non-uniform thickness, featuring a first area with a first thickness and a second area with a second thickness that is different from the first thickness. This local variation in thickness allows different regions to serve different functions: the thinner first area provides better optical access for sensing while the thicker second area provides structural support and protection, thereby achieving high fingerprint resolution without compromising overall sensing area integrity
Solution Approach 2:
The patent introduces a vertical dimension variation through the non-uniform insulating layer thickness, transitioning from a uniform planar structure to a three-dimensional profile. By varying the thickness in the vertical dimension across different horizontal areas, the design optimizes both optical access for high-resolution sensing and structural integrity, effectively resolving the contradiction between reduced sensing area and maintained resolution
2Reliability
If the insulating layer thickness is increased to protect the optical sensing element, then the protection is improved, but the optical access is reduced
Solution Approach 1:
The insulating layer features localized thickness variations where the first area has a first thickness optimized for optical access to the optical sensing element, while the second area has a second thickness optimized for protection. This local differentiation allows the structure to simultaneously achieve both optical accessibility and protective functions without compromise
Solution Approach 2:
The insulating layer is segmented into distinct functional areas: a first area providing optical access pathways and a second area providing protective coverage. This segmentation allows each region to be optimized for its specific function, with the first area maintaining thinner profiles for light transmission and the second area providing enhanced protection for the optical sensing element
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
This configuration reduces the effective fingerprint area to be equal to or less than the fingerprint pitch, thereby increasing the resolution of sensed fingerprints and improving biometric information recognition accuracy.
Implementation Method 1
an optical sensing element disposed on the base layer
Implementation Method 2
a light emitting element disposed on the base layer
Data Source
AI summary
A display device includes a display module and a window disposed on the display module. The display module includes a base layer, a light emitting element disposed on the base layer, an optical sensing element disposed on the base layer, a thin film encapsulation layer that covers the light emitting element and the optical sensing element, an insulating layer disposed on the thin film encapsulation layer, a light blocking pattern disposed on the insulating layer, and a color filter disposed on the insulating layer. The insulating layer includes a first area that overlaps the light emitting element and a second area that overlaps the optical sensing element, and the second area has a thickness greater than a thickness in the first area. The light blocking pattern includes a first opening that corresponds to the light emitting element and a second opening that corresponds to the optical sensing element.