Infrared Sensor Film With Collimating Optics for Display Imaging
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Solution Overview
Problem
Existing display systems struggle to effectively image user body portions such as fingers or veins using both visible and infrared wavelengths while maintaining high optical performance across varying incident angles.
Innovation Solution
A display system with an optical stack comprising multiple polymeric layers and a light collimating film, designed to optimize optical reflectance and transmittance across visible and infrared ranges, ensuring co-extensive optically active regions with the display panel and sensor, and incorporating alternating first and second regions to manage light absorption and transmission efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional optical stack is used, then the structure is simple, but the optical reflectance and transmittance performance across visible and infrared wavelengths at varying incident angles is insufficient
Solution Approach 1:
The optical stack is segmented into multiple functional layers including a first optical reflector with 30-100 polymeric layers for infrared reflectance, a light collimating film with alternating first and second regions for light direction control, and a second optical reflector. Each segment performs a specific optical function to collectively achieve superior broadband performance across visible and infrared wavelengths at varying incident angles.
Solution Approach 2:
The patent employs composite material structures where the first optical reflector uses alternating polymeric layers with different refractive indices, the light collimating film combines transparent and absorbing regions, and the second optical reflector uses similar composite layering. These composite structures enable simultaneous optimization of reflectance and transmittance across multiple wavelength ranges.
2Reliability
If the optical stack uses many polymeric layers to improve infrared reflectance, then the infrared optical performance improves, but the manufacturing complexity increases
Solution Approach 1:
The patent specifies precise parameter ranges to optimize performance while managing manufacturability: 30-100 polymeric layers with each layer being 50-200 nm thick, first regions with height-to-width ratio ≥2, and specific absorbance/transmittance thresholds. These parameter specifications enable systematic manufacturing control despite the multi-layer complexity.
Solution Approach 2:
Different regions of the light collimating film have specialized properties: first regions are transparent with specific transmittance ≥50% to allow light passage, while second regions have absorbance ≥30% to absorb excess light. This local differentiation optimizes overall optical performance while enabling targeted manufacturing approaches for each region type.
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 system achieves enhanced imaging capabilities for user body portions by maintaining high optical reflectance and transmittance across different wavelengths and angles, improving the visibility and detection of features like fingers or veins.
Implementation Method 1
the plurality of polymeric layers has an average optical reflectance of greater than about 70% in the visible wavelength range
Implementation Method 2
an optical transmittance of greater than about 30% for the at least the first wavelength in the infrared wavelength range
Implementation Method 3
the second regions of the light collimating film have an average optical absorbance of greater than about 30%
Implementation Method 4
For the second incident angle and for each of the visible and infrared wavelength ranges, the optical stack has an optical transmittance of less than about 10%
Data Source
AI summary
A display system for imaging a user body portion includes a display panel, an optical sensor disposed on the display panel and configured to detect light reflected by the user body portion, and an optical stack disposed between the display panel and the optical sensor. The optical stack includes a first optical reflector and a light collimating film. The light collimating film includes a plurality of substantially coplanar alternating first and second regions. For an incident light, a visible wavelength range, and an infrared wavelength range, and for each of a first incident angle of less than about 5 degrees and a second incident angle of between about 40 degrees and about 70 degrees, the plurality of polymeric layers has an average optical reflectance of greater than about 70% in the visible wavelength range and an optical transmittance of greater than about 30% in the infrared wavelength range.