Optical Fingerprint Chip Filter Integration for Thin Under-Display Design
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Solution Overview
Problem
The challenge in developing an optical fingerprint apparatus for large-area fingerprint identification under a screen is the fragility of thin glass substrates, leading to low yield and increased thickness, which compromises mechanical reliability and full-screen implementation due to the need for thicker substrates to support larger filters and micro-lens arrays.
Innovation Solution
Integrating a filter structure directly onto the optical fingerprint chip, eliminating the need for a thick glass substrate, and using a micro-lens array as a light directing component, while ensuring mechanical reliability through a support structure, thereby reducing the overall thickness and enhancing filtering efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a thinner glass substrate is used for the filter, then the thickness of the optical fingerprint apparatus is reduced, but the glass substrate becomes fragile and prone to fragmentation during preparation, resulting in low product yield
Solution Approach 1:
The patent integrates the filter layer directly onto the optical fingerprint chip substrate, eliminating the need for a separate thick glass substrate. This merging of the filter and chip into a single integrated structure reduces overall thickness while maintaining mechanical strength, as the filter is deposited directly on the chip's sensing surface rather than requiring a separate glass support layer.
Solution Approach 2:
The patent employs a thin film filter layer deposited directly on the optical chip substrate, replacing the traditional thick glass substrate. This thin film approach allows the filter to be integrated into the chip structure itself, achieving reduced thickness while the underlying chip substrate provides the necessary mechanical support and reliability.
2Reliability
If a glass substrate with thickness more than 200μm is used for large-area fingerprint identification, then the mechanical reliability is improved, but the thickness of the entire optical fingerprint apparatus increases
Solution Approach 1:
The patent combines the filter function with the optical fingerprint chip by depositing the filter layer directly onto the chip's sensing surface. This integration eliminates the need for a separate thick glass substrate that would be required to support large-area filters, thereby maintaining mechanical reliability while significantly reducing the overall apparatus thickness.
Solution Approach 2:
The optical fingerprint chip substrate serves multiple functions: it acts as the structural support for the sensing array, provides the mounting surface for the filter layer, and forms part of the optical path. This multi-functionality eliminates the need for separate support substrates, reducing overall thickness while maintaining the mechanical strength needed for large-area devices.
3Object-affected harmful factors
If the filter layer is deposited on a glass substrate, then the filtering function is achieved, but the overall structure becomes complex and the thickness increases
Solution Approach 1:
The patent merges the filter layer with the optical fingerprint chip by depositing it directly onto the chip's sensing surface. This integration simplifies the overall structure by eliminating separate glass substrate and filter assembly steps, reducing structural complexity while maintaining effective light filtering through the directly deposited filter layer.
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 approach allows for a thinner optical fingerprint apparatus with improved mechanical reliability and expanded fingerprint detection area, enabling full-screen solutions without compromising performance, thus addressing the limitations of existing technologies.
Implementation Method 1
a filter structure 33, where the filter structure 33 is deposited or sputtered on the optical fingerprint chip 31
Implementation Method 2
using a micro-lens array as a light directing component
Implementation Method 3
the filter structure 33 is deposited or sputtered on the optical fingerprint chip 31
Implementation Method 4
the filter structure 33 is deposited or sputtered on the optical fingerprint chip 31
Data Source
Figure 1A~2
Figure 3~5
Figure 6~7
AI summary
The present application provides an optical fingerprint apparatus and an electronic device, which could reduce a thickness of the optical fingerprint apparatus. The optical fingerprint apparatus is applied to an electronic device having a display screen and configured to be disposed under the display screen, and the optical fingerprint apparatus comprises: an optical fingerprint chip configured to receive a fingerprint detecting signal, wherein the fingerprint detecting signal is used to detect fingerprint information of a finger; and a filter structure, wherein the filter structure is deposited or sputtered on the optical fingerprint chip.