Fingerprint Sensing Module Interposer Adhesion and Stray Light Control
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Solution Overview
Problem
Under-screen fingerprint sensing modules face issues with stray light causing blurred images due to large gaps between micro lenses, and poor material compatibility leads to adhesion problems with light-shielding layers, affecting production yield.
Innovation Solution
A fingerprint sensing module design featuring a light-shielding layer with recessed openings and an interposer that stabilizes micro lenses, reducing the risk of peeling and enhancing optical characteristics for anti-counterfeiting functions while simplifying manufacturing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a light-shielding layer is arranged between micro lenses to block stray light, then image clarity is improved, but material compatibility issues cause poor adhesion and peeling of the light-shielding layer
Solution Approach 1:
An interposer layer is introduced between the light-shielding layer and the micro lenses to serve as a mediator that improves adhesion. The interposer layer is made of a material that is compatible with both the light-shielding layer and the micro lenses, thereby preventing peeling while maintaining the light-shielding function.
Solution Approach 2:
The patent uses composite material structure by combining the light-shielding layer, interposer layer, and micro lenses into a multi-layer composite structure. Each layer is selected with specific material properties to achieve both optical performance and mechanical adhesion reliability.
2Manufacturing precision
If micro lenses are directly placed on the light-shielding layer to block stray light, then image clarity is improved, but production yield decreases due to peeling issues
Solution Approach 1:
The interposer layer acts as an intermediary that resolves the adhesion problem between the light-shielding layer and micro lenses, thereby eliminating the peeling defect that reduces production yield while preserving the stray light blocking function.
3Reliability
If conventional color-resistance anti-counterfeiting structures are used, then anti-counterfeiting function is achieved, but manufacturing processes become more complex
Solution Approach 1:
The interposer layer serves multiple functions: it provides adhesion between layers, enables anti-counterfeiting through optical characteristic differences, and maintains structural integrity. This multi-functionality eliminates the need for separate color-resistance anti-counterfeiting structures, simplifying the manufacturing process.
Solution Approach 2:
The patent utilizes optical characteristic differences (such as spectral distribution variations) of light passing through different regions to achieve anti-counterfeiting functionality. This approach replaces complex color-resistance structures with a simpler optical differentiation mechanism.
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 module achieves improved image clarity by reducing stray light incidence and stabilizing micro lens adhesion, increasing production yield and flexibility in material selection, and providing an anti-counterfeiting feature with fewer manufacturing steps.
Implementation Method 1
the sensing light will be reflected by the user's finger (diffusely) into the fingerprint sensing module under the display panel
Implementation Method 2
the reflected light will be converged on the photosensitive element through a plurality of micro lenses and a collimation structure
Implementation Method 3
a plurality of micro lenses are disposed on the interposer and respectively overlap the first openings
Implementation Method 4
light pass through these first openings and are transmitted to the corresponding photosensitive device
Data Source
AI summary
A fingerprint sensing module including a substrate, a plurality of photosensitive devices, a collimation structure layer, a light-shielding layer, an interposer and a plurality of micro lenses is provided. The photosensitive devices are disposed on the substrate. The collimation structure layer is disposed on the photosensitive devices. The light-shielding layer is disposed on the collimation structure layer and has a surface and a plurality of first openings recessed from the surface. The first openings respectively overlap the photosensitive devices. The interposer is disposed on the collimation structure layer and positioned in a part of the first openings of the light-shielding layer. The micro lenses are disposed on the interposer and respectively overlap the first openings.