Fingerprint Sensor Optical Pattern Polishing for Higher Transmittance
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Solution Overview
Problem
Display devices with integrated fingerprint detection sensors face challenges in achieving improved light transmittance, as existing methods often result in residual light blocking materials on the surface of transmissive portions, affecting the sensor's performance.
Innovation Solution
A manufacturing method for a detection sensor involving a biometric information sensing layer with a transistor, an initial optical pattern layer forming transmissive portions and light blocking portions with specific zeta potentials, and an abrasive with polyacrylic acid and polystyrene sulfonate for chemical mechanical polishing to expose the transmissive surfaces, ensuring complete removal of light blocking materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a light blocking material is coated to cover the upper surface of transmissive portions, then light blocking performance is improved, but light transmittance deteriorates due to residual material on the surface
Solution Approach 1:
The patent changes the zeta potential parameter of the abrasive particles to be opposite in sign to the light blocking material surface charge. This parameter change enables selective adsorption of the light blocking material by the abrasive, allowing complete removal without residue and thereby improving light transmittance while maintaining light blocking performance through controlled material properties
Solution Approach 2:
The patent replaces conventional mechanical polishing methods with a chemical-mechanical polishing approach where electrostatic interactions (chemical aspect) between the charged abrasive and light blocking material enable selective removal. The charged abrasive particles selectively adsorb and remove the light blocking material through electrostatic attraction, substituting pure mechanical abrasion with a combined chemical-mechanical process that achieves residue-free removal
2Ease of manufacture
If conventional polishing methods are used to remove light blocking material, then manufacturing simplicity is maintained, but manufacturing precision deteriorates due to incomplete removal and surface residue
Solution Approach 1:
The patent modifies the abrasive particle properties by controlling their zeta potential to be opposite in sign to the light blocking material surface charge. This parameter change enables selective adsorption and complete removal of the light blocking material, achieving superior surface cleanliness and manufacturing precision while maintaining process simplicity through a single polishing step
Solution Approach 2:
The patent introduces charged abrasive particles as an intermediary between the polishing pad and the light blocking material. These abrasive particles act as mediators that selectively adsorb the light blocking material through electrostatic attraction, enabling complete and precise removal without direct mechanical contact that would leave residues, thereby improving manufacturing precision
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 method enhances light transmittance by completely removing light blocking materials from the surface of transmissive portions, improving the detection sensor's performance and accuracy.
Implementation Method 1
spraying an abrasive having the first zeta potential on the initial light blocking portion, and polishing the initial light blocking portion such that the upper surface of the transmissive portions is exposed to form a light blocking portion
Data Source
AI summary
A method of manufacturing a detection sensor is disclosed. The method includes forming a biometric information sensing layer including a transistor on a base layer, forming an initial optical pattern layer on the biometric information sensing layer, patterning the initial optical pattern layer to form a plurality of transmissive portions spaced apart from each other and having a first zeta potential, coating a light blocking material to form an initial light blocking portion that covers a side surface and an upper surface of the transmissive portions and has a second zeta potential different from the first zeta potential, and polishing the initial light blocking portion such that the upper surface of the transmissive portions is exposed to form a light blocking portion. The initial light blocking portion is polished by the abrasive, which has the first zeta potential, using a pad.