Fingerprint Recognition Device Using Optical Gratings
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Solution Overview
Problem
Current fingerprint recognition structures in display devices are overly complex, resulting in thick and bulky devices due to the use of pinhole light filter and lens structures.
Innovation Solution
A fingerprint recognition device with a light transmission substrate, a light guiding layer, and recognizer units comprising a first optical grating, a second optical grating, and a detector module, where the first optical grating diffractively couples fingerprint light rays within a preset angle range into the light guiding layer, and the second optical grating extracts and transmits these rays to the detector module for intensity detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pinhole light filter and lens structures are used for fingerprint recognition, then fingerprint recognition function is achieved, but device structure becomes complex and thickness increases
Solution Approach 1:
The patent extracts and eliminates the pinhole light filter and lens structures from the fingerprint recognition system, replacing them with a simplified optical path that uses only a light guiding layer and detector module, thereby reducing structural complexity while maintaining recognition functionality
Solution Approach 2:
The light guiding layer serves multiple functions: it guides light from the display substrate, provides structural support, and enables the optical path for fingerprint recognition, replacing the need for separate pinhole filters and lenses
2Reliability
If pinhole light filter and lens structures are used for fingerprint recognition, then fingerprint recognition function is achieved, but device thickness increases
Solution Approach 1:
The patent removes the thickness-contributing pinhole light filter and lens components, retaining only the essential light guiding layer and detector module, which significantly reduces the overall device thickness while preserving fingerprint recognition capability
Solution Approach 2:
The light guiding layer is implemented as a thin film structure that provides sufficient optical guidance functionality while minimizing thickness, enabling the fingerprint recognition module to be integrated into thin display devices
3Reliability
If traditional fingerprint recognition structures are used, then recognition function is provided, but manufacturing cost increases
Solution Approach 1:
The patent eliminates complex optical components (pinhole filters, lenses) that are difficult and expensive to manufacture, replacing them with a simpler light guiding layer structure that is easier to fabricate and integrate, thereby reducing manufacturing costs
Solution Approach 2:
The patent merges the light guiding function and structural support function into a single layer, reducing the number of components that need to be manufactured and assembled, which simplifies the manufacturing process and reduces costs
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 solution simplifies the structure, making the fingerprint recognition device thinner, lighter, and more cost-effective while improving user experience by accurately detecting fingerprint information with reduced thickness and increased accuracy.
Implementation Method 1
the first optical grating is configured to diffractively couple a fingerprint light ray having an incident angle within a preset angle range to the light guiding layer
Implementation Method 2
the second optical grating is configured to extract the fingerprint light ray in the light guiding layer to the detector module
Data Source
AI summary
A fingerprint recognition device, a recognition device and a display device are provided to include: a light guiding layer and a plurality of recognizer units, on a side of a light transmission substrate. Each recognizer unit includes: a first optical grating which is between the light guiding layer and the light transmission substrate and is configured to diffractively couple a fingerprint light ray having an incident angle within a preset angle range to the light guiding layer; a second optical grating on a side of the light guiding layer; and a detector module on a side of the second optical grating away from the light guiding layer. The second optical grating is configured to extract the fingerprint light ray in the light guiding layer to the detector module, and the detector module is configured to detect a light intensity of the fingerprint light ray.