Fingerprint Sensor Optical Layer Layout for In-Display Recognition
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Solution Overview
Problem
Fingerprint sensors integrated into display devices face limitations in expanding the display area due to their placement, particularly when disposed in bezel or non-display areas, which restricts the widening of the display area.
Innovation Solution
A fingerprint sensor design incorporating a light sensing layer with a light transmitting member, a light blocking member, and a planarization member, where the light blocking member surrounds the light transmitting areas and the planarization member overlaps the light blocking member, optimizing light transmittance and blocking to enhance fingerprint recognition while minimizing space usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the fingerprint sensor is disposed in the bezel area or non-display area, then the fingerprint sensor can be integrated into the display device, but the display area cannot be widened
Solution Approach 1:
The fingerprint sensor is integrated into the display area by utilizing the vertical dimension and optical layer structure rather than occupying horizontal bezel space. The optical layer with light transmitting and blocking areas enables the sensor to function within the display plane, effectively adding fingerprint recognition capability without reducing display area.
2Object-affected harmful factors
If the light blocking member is disposed to surround the light transmitting areas, then light blocking performance is improved, but manufacturing complexity increases
Solution Approach 1:
The light blocking member and planarization member are combined into a single integrated structure. The light blocking member serves dual functions: blocking light in the light blocking area and providing a planar upper surface through its protruding portion. This merging reduces the number of separate components and simplifies the manufacturing process while maintaining effective light blocking performance.
3Shape
If the planarization member overlaps the light blocking member, then surface planarity is improved, but the risk of over-etching and contamination increases
Solution Approach 1:
The planarization member acts as an intermediary protective layer during the etching process. By positioning the planarization member to overlap and cover portions of the light blocking member, it serves as a protective mask that prevents over-etching and reduces contamination risk during manufacturing, while still allowing the light blocking function to operate effectively through the exposed portions.
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 design allows for efficient fingerprint recognition within the display area, maintaining high light transmittance and reliability of the fingerprint sensor, while minimizing the risk of over-etching and contamination during manufacturing, thus enhancing the overall performance and usability of the fingerprint sensor.
Implementation Method 1
a light transmitting member disposed in the plurality of light transmitting areas... light transmittance of the light transmitting member is greater than light transmittance of the planarization member
Implementation Method 2
a light blocking member disposed in the light blocking area... light transmittance of the planarization member is greater than light transmittance of the light blocking member
Implementation Method 3
the planarization member includes a third organic material and a positive-type photosensitive material
Data Source
AI summary
A fingerprint sensor includes: a light sensing layer including a light sensing element; and an optical layer including a plurality of light transmitting areas, a light blocking area, a light transmitting member disposed in the plurality of light transmitting areas, a light blocking member disposed in the light blocking area, and a planarization member disposed on the light blocking member, wherein the light blocking area surrounds the plurality of light transmitting areas, wherein the light transmitting member includes a first organic material, wherein the light blocking member includes a second organic material, and wherein the planarization member includes a third organic material and a positive-type photosensitive material.