Optical Sensor Light Transmittance via Refractive Index Matching
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Solution Overview
Problem
Current display devices with fingerprint sensing capabilities face challenges in achieving high transmittance, leading to poor light reception and deteriorated sensing functions due to deviations in light transmittance caused by the stack structure and thickness distribution of layers.
Innovation Solution
A display device structure is designed with a flexible substrate having a specific stack structure and refractive index distribution across its layers, including organic and inorganic materials, and an adhesive member with optimized refractive indices to minimize deviations in light transmittance, enhancing the optical sensor's ability to receive reflected light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a stack structure with multiple layers is used in the display device, then the device functionality is enhanced, but deviations in light transmittance occur due to thickness distribution of layers
Solution Approach 1:
The patent changes the refractive index parameter of the adhesive member to match that of the barrier layer (both set to approximately 1.7). This parameter matching minimizes optical deviations and maintains uniform light transmittance across the display device while preserving the multi-layer stack structure's functional benefits.
Solution Approach 2:
The patent uses a composite material approach by selecting an adhesive member with specific refractive index properties that complement the barrier layer. This composite material strategy ensures optimal optical performance while maintaining the structural integrity and functionality of the multi-layer display device.
2Strength
If the adhesive member thickness is increased to improve adhesion, then bonding strength is enhanced, but light transmittance deviations increase
Solution Approach 1:
The patent changes the refractive index parameter of the adhesive member to match the barrier layer (both approximately 1.7). This refractive index matching allows the adhesive member to maintain adequate thickness for strong bonding while minimizing light transmittance deviations, as the matched refractive indices reduce optical interface effects.
3Strength
If the barrier layer refractive index is optimized for adhesion, then bonding performance improves, but light transmittance uniformity deteriorates
Solution Approach 1:
The patent optimizes the refractive index parameter of the barrier layer to approximately 1.7, which simultaneously achieves strong adhesion performance and uniform light transmittance. This is accomplished by matching the barrier layer's refractive index with that of the adhesive member, creating optical compatibility while maintaining bonding strength.
4Adaptability or versatility
If an optical sensor is added below the protective film for fingerprint sensing, then sensing functionality is provided, but light reception is poor due to transmittance losses
Solution Approach 1:
The patent optimizes the refractive indices of the barrier layer and adhesive member (both approximately 1.7) to minimize light transmittance deviations. This ensures maximum light reaches the optical sensor below the protective film, improving light reception efficiency for fingerprint sensing while maintaining the sensor's functional integration.
Solution Approach 2:
The barrier layer and adhesive member act as optical intermediaries between the light source and the optical sensor. By matching their refractive indices, they facilitate efficient light transmission through the protective film structure, enabling the optical sensor to receive sufficient reflected light for accurate fingerprint sensing.
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 improves light reception rates and maintains high transmittance, thereby enhancing the fingerprint sensing functionality of the optical sensor.
Implementation Method 1
a photodetector that receives light emitted by the display device in a window direction that is reflected in a substrate direction from the optical member
Implementation Method 2
light emitted in a window direction that is reflected in a substrate direction from the optical member
Data Source
AI summary
A display device includes a substrate; a barrier layer above a first surface of the substrate; a protective film below a second surface of the substrate opposite the first surface; an adhesive member between the substrate and the protective film; and an optical sensor below a second surface of the protective film opposite a first surface of the protective film that faces the second surface of the substrate.