Fingerprint Sensor Optical Path Simplification
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Solution Overview
Problem
Existing optical fingerprint identification apparatuses have complex optical path structures and cumbersome processing processes, leading to low output efficiency and increased production costs due to the need for multiple transparent dielectric layers and the use of black matrix photoresist, which complicates the adhesion and coating processes.
Innovation Solution
A fingerprint identification apparatus with a simplified optical path structure using a light blocking layer made by coating film with inverse trapezoid holes, reducing the number of transparent dielectric layers and eliminating the need for black matrix photoresist, and incorporating color filter units formed by organic or inorganic materials to transmit specific light bands, thereby improving mass production efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If multiple transparent dielectric layers are used as adhesion buffer and flat buffer layers, then the structural stability and flatness are improved, but the device complexity and processing difficulty increase
Solution Approach 1:
The patent removes the transparent dielectric buffer layer between the color filter layer and microlens array layer, extracting the unnecessary component while maintaining the flatness requirement through direct contact design between the color filter layer and microlens array layer
Solution Approach 2:
The patent merges the adhesion function and flatness function into a single interface design between the color filter layer and microlens array layer, eliminating the need for a separate transparent dielectric buffer layer while achieving both structural stability and optical flatness
2Object-affected harmful factors
If black matrix photoresist is used for the light blocking layer, then the light blocking performance is improved, but the ease of manufacture and processing complexity worsen
Solution Approach 1:
The patent replaces the complex black matrix photoresist process with a simpler organic coating material that can be directly applied and cured, using a disposable, easy-to-process material that achieves the same light blocking function without requiring complex photolithography steps
Solution Approach 2:
The patent substitutes the mechanical photolithography process (black matrix photoresist) with a chemical/thermal curing process (organic coating material), replacing complex mechanical alignment and exposure steps with a simpler coating and curing operation
3Reliability
If multiple buffer layers are used between optical components, then the adhesion and flatness are improved, but the productivity and mass production efficiency decrease
Solution Approach 1:
The patent removes the transparent dielectric buffer layer between the color filter layer and microlens array layer, extracting the unnecessary component that slows down production while maintaining adhesion quality through direct contact design
Solution Approach 2:
The patent incorporates the adhesion function directly into the color filter layer and microlens array layer interface design, performing the adhesion function in advance through material selection and surface treatment rather than requiring an additional buffer layer during assembly
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
The solution simplifies the optical path laminated structure and processing process, enhancing mass production efficiency while maintaining effective fingerprint identification performance without affecting the quality of fingerprint images.
Implementation Method 1
an infrared radiation cut filter layer provided above the fingerprint sensor chip
Implementation Method 2
the first color filter units being configured to transmit light of at least one waveband among red light, blue light and green light
Implementation Method 3
the fingerprint sensor chip is configured to receive an optical signal returned by a finger above the display screen, converged by the microlens array
Implementation Method 4
a light blocking layer provided on an upper surface of the infrared radiation cut filter layer by means of coating film
Data Source
Figure 1
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AI summary
Embodiments of the present application disclose a fingerprint identification apparatus and an electronic device, which can simplify an optical path laminated structure and processing process, thereby improving efficiency of mass production. The fingerprint identification apparatus includes: a fingerprint sensor chip; an infrared radiation cut filter layer provided above the fingerprint sensor chip; a light blocking layer provided on an upper surface of the infrared radiation cut filter layer by means of coating film, the light blocking layer being provided with a first hole array, and cross sections of holes in the first hole array being inverse trapezoid; a light transmitting dielectric layer including first color filter units, the first color filter units being formed in part of the holes in the first hole array to cover the part of the holes; and a microlens array provided above the light transmitting dielectric layer.