Stacked Array Lens Optical Fingerprint Identification System
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Solution Overview
Problem
Conventional in-display optical fingerprint identification systems face challenges with poor fingerprint image quality due to the use of a single collimator layer, which limits identification accuracy and increases difficulty when receiving light at different fields of view, and require thicker lens modules for improved image quality, hindering the miniaturization of electronic devices.
Innovation Solution
The optical fingerprint identification system employs a stacked configuration of first and second array lens elements with coaxial optical axes, forming imaging units, along with a light emitting layer and image sensor, to achieve effective light convergence and aberration correction, while maintaining a thin form factor, using materials like glass or plastic for the lens elements and incorporating filter coatings to enhance image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single collimator layer is used to receive light, then the device structure is simple, but the fingerprint image quality is poor and identification accuracy decreases
Solution Approach 1:
The optical layer is segmented into multiple functional layers: a collimator layer for light collection and multiple array lens elements for light convergence. Each layer performs a specific optical function, with the collimator layer having a lattice partition for light reception and the array lens elements providing focused imaging capability. This segmentation allows each component to be optimized for its specific function while working together to achieve high image quality.
2Measurement precision
If a micro lens is disposed under the display to improve fingerprint image quality, then the image quality improves, but the lens module thickness increases resulting in a thicker electronic device
Solution Approach 1:
The patent transitions from a single-plane lens configuration to a three-dimensional stacked array configuration. Multiple array lens elements are arranged in layers at different positions along the optical axis, creating a volumetric optical structure. This dimensional transformation allows the system to achieve superior light convergence and image quality while maintaining a compact overall footprint, as the stacked arrangement efficiently utilizes vertical space rather than requiring a single thick lens element.
3Adaptability or versatility
If the collimator layer receives light at different fields of view, then the field of view coverage is comprehensive, but the fingerprint identification difficulty increases due to poor image quality
Solution Approach 1:
The array lens elements are strategically positioned at different locations and depths within the optical layer, with each element optimized for capturing light from specific field of view regions. The lattice partition of the collimator layer directs light from different angular regions to corresponding array lens elements, ensuring that each region of the field of view is captured with high quality by the appropriately positioned lens 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 significantly improves fingerprint image quality, enhances identification accuracy, and reduces the overall thickness of the device, enabling miniaturization while maintaining high performance and compatibility with smart mobile devices.
Implementation Method 1
The optical layer includes a first array layer and a second array layer... Each of the first array lens elements and a corresponding second array lens element of the second array layer are coaxial along an optical axis and form an imaging unit
Implementation Method 2
The light emitting layer is disposed below the cover... The display or a lateral light-guiding medium can be a light source to emit light onto user's fingerprint
Implementation Method 3
employ a stacked configuration of first and second array lens elements with coaxial optical axes, forming imaging units, along with a light emitting layer and image sensor, to achieve effective light convergence and aberration correction
Data Source
AI summary
An optical fingerprint identification system includes a cover, a light emitting layer, an optical layer, an image sensor and a base that are sequentially disposed from top to bottom. The cover has a fingerprint contact surface on top. The image sensor has an image surface. The optical layer includes a first array layer and a second array layer, and the first array layer is stacked on top of the second array layer. The first array layer and the second array layer respectively include a plurality of first array lens elements and a plurality of second array lens elements respectively arranged at equal intervals in a first direction. Each of the first array lens elements and a corresponding second array lens element of the second array layer are coaxial along an optical axis and form an imaging unit.