Under-screen Fingerprint Detection via Light Shielding Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing under-screen optical fingerprint identification technology is limited by the size of the micro lens array, which restricts the fingerprint identification region and affects the performance of fingerprint recognition.
Innovation Solution
The proposed solution involves a fingerprint detection apparatus with a micro lens array and a light shielding layer, where the micro lenses are positioned above the optical sensing pixels, and the light shielding layer has openings that allow oblique light signals to be converged and transmitted to the pixels, effectively increasing the fingerprint identification region without increasing the size of the micro lens array.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the size of the micro lens array is increased to expand the fingerprint identification region, then the fingerprint identification region is improved, but the device complexity and cost increase
Solution Approach 1:
The patent introduces a light shielding layer with openings positioned between the micro lens array and optical sensing pixel array, creating a new spatial dimension for controlling light paths. This allows oblique light signals to be redirected to adjacent pixels, effectively expanding the fingerprint identification region without increasing the micro lens array size.
Solution Approach 2:
The light shielding layer with openings acts as an intermediary element that mediates between the micro lens array and optical sensing pixel array. It selectively blocks and transmits light signals, enabling oblique light from the finger to reach adjacent pixels and thereby expanding the identification region.
2Area of stationary object
If the micro lens array size is increased to improve fingerprint detection coverage, then the detection coverage is improved, but the thickness of the apparatus increases
Solution Approach 1:
The patent utilizes the vertical dimension by positioning the light shielding layer with openings between the micro lens array and pixel array. This vertical arrangement allows oblique light paths to be created within the existing thickness, expanding detection coverage without increasing overall apparatus thickness.
3Measurement precision
If oblique light signals are allowed to reach optical sensing pixels to expand identification region, then the fingerprint identification effect is improved, but Moire fringes may occur
Solution Approach 1:
The light shielding layer with selectively positioned openings extracts and transmits only specific oblique light signals that contribute to fingerprint identification, while blocking other light paths that would cause Moire fringes. This selective extraction improves identification effect while avoiding harmful interference patterns.
Solution Approach 2:
The light shielding layer has different opening configurations at different locations, creating local quality variations. This allows optimal control of light paths for each region, enabling oblique light to reach pixels for improved identification while preventing Moire fringes in specific areas through localized light blocking.
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 design enhances the field of view and robustness of the fingerprint detection apparatus, improves the fingerprint identification effect, especially for dry fingers, and reduces the thickness and cost of the apparatus while avoiding Moire fringes.
Implementation Method 1
each of the at least one micro lens converges oblique light signals in multiple directions reflected from a finger above the display screen to optical sensing pixels below the light shielding layer through openings provided in the at least one light shielding layer
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A fingerprint detection apparatus and an electronic device are provided. The fingerprint detection apparatus is applied under a display screen to achieve under-screen optical fingerprint detection, the fingerprint detection apparatus includes a plurality of fingerprint detecting units distributed in an array or arranged in a staggered manner, and the fingerprint detecting unit includes: a plurality of optical sensing pixels; at least one micro lens disposed above the plurality of optical sensing pixels; and at least one light shielding layer disposed between the at least one micro lens and the plurality of optical sensing pixels, each of the at least one light shielding layer being provided with an opening corresponding to the plurality of optical sensing pixels; where oblique light signals in multiple directions are respectively transmitted to the plurality of optical sensing pixels through an opening provided in the at least one light shielding layer after being converged by the at least one micro lens. According to the fingerprint detection apparatus, a fingerprint identification region of the fingerprint detection apparatus could be effectively increased without the increase of a size of a micro lens array.