Display Panel With Light-Collimating Protrusions for Fingerprint Sensing
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Solution Overview
Problem
Existing display technologies face challenges in achieving a high screen ratio due to the presence of fingerprint recognition units, which occupy front area and affect the screen's effective display space.
Innovation Solution
A display panel design with protrusions and openings in transparent layers to refract and collimate fingerprint detection light, enhancing light entry and improving fingerprint image quality and acquisition success rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fingerprint recognition unit is disposed on the front of the terminal device, then the fingerprint recognition function can be provided, but the screen ratio is reduced due to occupation of front area
Solution Approach 1:
The fingerprint recognition unit is relocated from the front surface to the rear surface of the display panel, transitioning from a two-dimensional front-mounted configuration to a three-dimensional rear-integrated configuration. This dimensional shift allows the fingerprint sensor to occupy space behind the display rather than reducing the visible screen area, thereby maintaining a high screen ratio while preserving fingerprint recognition functionality.
Solution Approach 2:
The fingerprint recognition unit is nested within the display panel structure, specifically positioned in the rear substrate layer. The sensor array is integrated into the multi-layer substrate configuration, allowing the fingerprint recognition function to be embedded within the display device's internal architecture rather than occupying external front space.
2Measurement precision
If light is transmitted directly to photosensitive elements without optical components, then the structure is simple, but the light entry amount is insufficient and image quality is poor
Solution Approach 1:
A convex lens with a curved surface is introduced between the light source and the photosensitive elements. The curved geometry of the convex lens enables effective light focusing and collimation, improving the light entry amount onto the photosensitive elements and thereby enhancing fingerprint image quality through optical concentration of photons.
Solution Approach 2:
A convex lens is introduced as an intermediary optical component between the light source and the photosensitive elements. This intermediary element facilitates efficient light transmission and focusing, acting as a mediator that improves the coupling between the light source and the sensor array, thereby enhancing image acquisition quality.
3Reliability
If the protrusions and openings are precisely aligned to maximize light entry, then the light collimation is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The convex lens structure is merged with the existing substrate manufacturing process, where the lens is formed as an integral part of the rear substrate rather than being a separate component requiring precise alignment. This integration combines the optical function with the structural substrate, reducing the number of separate alignment operations and lowering manufacturing precision requirements.
Solution Approach 2:
The optical parameters of the convex lens, including its curvature radius and refractive index, are optimized to achieve effective light focusing while being compatible with standard manufacturing tolerances. By carefully selecting and adjusting these parameters, the system achieves good light collimation without requiring extremely tight manufacturing precision, balancing optical performance with manufacturability.
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
The design improves the collimation degree of fingerprint detection light, increasing the effective light entering amount of photosensitive elements, thereby enhancing fingerprint image quality and acquisition success rate.
Implementation Method 1
the protrusions, the first openings, and the photosensitive elements correspond one by one, and orthographic projections of the protrusions, the first openings, and the photosensitive elements on the second substrate are at least partially overlapped
Data Source
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AI summary
A display panel includes a first substrate, a second substrate disposed opposing the first substrate, a first transparent layer, a first light shield layer, and a photosensitive element layer located between the first substrate and the second substrate. The first transparent layer, the first light shield layer, and the photosensitive element layer are sequentially disposed along a direction from the first substrate to the second substrate. The first transparent layer includes a plurality of protrusions extending toward the first substrate. The first light shield layer includes a plurality of first openings, and the photosensitive element layer includes a plurality of photosensitive elements for acquiring a fingerprint image. The protrusions, the first openings, and the photosensitive elements have one-to-one correspondence, and have at least partially overlapped orthographic projections on the second substrate.