Under-screen Fingerprint Detection Using Light Shielding Layer
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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 efficiency of fingerprint detection, especially for dry fingers.
Innovation Solution
A fingerprint detection apparatus is designed with a plurality of optical sensing pixels and micro lenses arranged in an array or staggered manner, where a light shielding layer with openings allows oblique light signals to be converged onto the pixels, increasing the fingerprint identification region without enlarging the micro lens array, thereby improving the field of view and tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the micro lens array size is increased to expand the fingerprint identification region, then the fingerprint identification region is improved, but the device thickness 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 directed to sensing pixels through vertically stacked components rather than requiring a larger horizontal lens array, thus expanding the fingerprint identification region without increasing device thickness
Solution Approach 2:
The patent employs a nested structure where the light shielding layer with openings is positioned within the vertical stack between the micro lens array and optical sensing pixel array. This nested arrangement allows multiple functional layers to occupy the same horizontal footprint while maintaining distinct optical functions, enabling expanded light collection angles without increasing the overall device footprint or thickness
2Area of stationary object
If the micro lens array size is increased to expand the fingerprint identification region, then the fingerprint identification region is improved, but the manufacturing cost increases
Solution Approach 1:
By transitioning from a horizontal expansion approach to a vertical stacking approach with the light shielding layer, the patent achieves expanded fingerprint identification region using the same number of micro lenses and sensing pixels, thereby avoiding the increased manufacturing costs associated with larger arrays
Solution Approach 2:
The light shielding layer is segmented with multiple openings positioned at specific locations to direct oblique light from different angles to appropriate sensing pixels. This segmentation allows the system to capture light from a wider area without requiring proportionally more expensive and larger micro lens and pixel arrays
3Adaptability or versatility
If oblique light signals from multiple directions are captured, then the field of view and robustness are improved, but the optical system complexity increases
Solution Approach 1:
The light shielding layer with openings serves as an intermediary optical element that简单地 directs oblique light signals from multiple directions to the appropriate sensing pixels. This intermediary structure achieves expanded field of view and improved robustness without requiring complex multi-element lens systems or sophisticated optical designs
Solution Approach 2:
The light shielding layer features locally optimized openings positioned at specific locations to capture and direct light from particular angles. Each opening is strategically placed to address specific directional light paths, achieving comprehensive multi-directional light collection through simple local structural variations rather than global system complexity
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 thickness and cost of the apparatus, enhances the robustness and field of view, and improves the fingerprint identification effect, particularly for dry fingers, by allowing oblique light signals to be detected from multiple directions.
Implementation Method 1
at least one micro lens disposed above the plurality of optical sensing pixels... oblique light signals in multiple directions reflected from a finger above the display screen 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
Implementation Method 2
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
Data Source
AI summary
A fingerprint detection apparatus and an electronic device are provided. The fingerprint detection apparatus is applied under a display screen, 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.