Optical Sensor Light Collimating Layer Debris Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional fingerprint sensors face challenges in structural strength and production yield due to debris and contaminants obstructing the light collimating layer during manufacturing, which reduces sensitivity and increases production costs.
Innovation Solution
A light collimating layer is formed with transparent pillars on the sensor pixel array and a metal layer between them, along with a mask layer to prevent obstruction and crosstalk, enhancing the structural integrity and performance of the optical sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional light collimating layer is used during manufacturing, then the manufacturing process is simpler, but debris and contaminants can obstruct the sensor pixels, reducing production yield and sensitivity
Solution Approach 1:
The light collimating layer is segmented into multiple functional components: transparent pillars (for light transmission and structural support), metal layer (for mechanical strength and debris barrier), and mask layer (for light blocking and pattern definition). This segmentation allows each component to perform its specific function optimally while collectively preventing debris obstruction of sensor pixels.
Solution Approach 2:
The light collimating layer uses a composite structure combining transparent material (for optical transmission), metal material (for structural strength and contamination barrier), and mask material (for light blocking). This composite approach leverages the advantages of each material to achieve both protective functionality and optical performance.
2Strength
If the light collimating layer structure is simplified for easier manufacturing, then production costs decrease, but structural strength is reduced making the sensor more vulnerable to damage
Solution Approach 1:
The structural strength function is separated from the optical function by introducing a dedicated metal layer component. The metal layer provides mechanical strength and acts as a barrier to contaminants, while the transparent pillars handle light transmission. This segmentation allows optimization of each component for its primary function.
Solution Approach 2:
Different regions of the light collimating layer have different properties: the metal layer provides strength and contamination barrier in areas where structural support is needed, while the transparent pillars provide optical transmission in areas where light passage is required. This local differentiation of material properties optimizes both strength and manufacturability.
3Productivity
If transparent pillars are added to the light collimating layer to prevent debris obstruction, then production yield improves, but light crosstalk between pixels increases
Solution Approach 1:
The mask layer acts as an intermediary between the transparent pillars and the sensor pixels. It blocks stray light and prevents crosstalk while allowing the transparent pillars to maintain their debris-protection function. The mask layer mediates between the need for structural protection and the need for precise light collimation.
Solution Approach 2:
The mask layer is selectively positioned to block light in specific areas where crosstalk would occur, while leaving other areas open for necessary light transmission. This local differentiation of light blocking properties allows the system to achieve both debris protection and precise light collimation.
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 prevents debris and contaminants from obstructing the sensor pixels, improves manufacturing yield, and enhances the sensitivity and performance of the optical sensor by ensuring proper light collimation and reducing unwanted light crosstalk.
Implementation Method 1
the light collimator is utilized to ensure that light which is incident to the sensor is parallel, to reduce energy loss from divergent light
Implementation Method 2
a plurality of transparent pillars disposed on the sensor pixel array
Data Source
AI summary
An optical sensor includes a substrate and a light collimating layer. The substrate includes a sensor pixel array having a plurality of sensor pixels. The light collimating layer is disposed on the substrate. The light collimating layer includes a patterned seed layer, a plurality of transparent pillars, a metal layer, and a mask layer. The patterned seed layer is disposed on the substrate. The patterned seed layer exposes the sensor pixel array. The transparent pillars are disposed on the sensor pixel array. The metal layer is disposed on the patterned seed layer and in between the transparent pillars. The mask layer is disposed on the metal layer.