Optical Light Redirecting Stack With Truncated Prisms for Low Distortion
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Solution Overview
Problem
Modern optical systems with light redirecting layers suffer from light distortion and splitting due to sharp prismatic structures, which affect the clarity and functionality of displays, particularly when detecting images like fingerprints.
Innovation Solution
An optical stack comprising stacked light redirecting layers with truncated and untruncated structures, where the truncated structures have planar top surfaces and untruncated structures meet at peaks, allowing for minimal light distortion and improved light transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If sharp prismatic structures are used in light redirecting layers, then light redirection efficiency is improved, but light distortion and splitting occur
Solution Approach 1:
The patent applies local quality by differentiating between two types of structures within the same light redirecting layer: truncated structures with planar top surfaces for regions requiring minimal distortion (such as fingerprint detection areas), and untruncated prismatic structures for regions requiring maximum light redirection. This spatial differentiation of structural properties allows simultaneous optimization of both light redirection efficiency and image clarity in different functional zones.
2Loss of information
If truncated structures with planar top surfaces are used, then light distortion is reduced, but light transmission efficiency may be compromised
Solution Approach 1:
The patent merges two previously separate structural approaches (truncated and untruncated structures) into a single integrated light redirecting layer. This combination allows the system to simultaneously achieve the distortion-reducing benefits of truncated structures and the high transmission efficiency of untruncated structures, with each structure type positioned in optimal locations to fulfill different functional requirements.
3Illumination intensity
If multiple light redirecting layers are stacked, then display brightness is enhanced, but device complexity increases
Solution Approach 1:
The patent segments the light redirecting function into multiple stacked layers, each containing a specific pattern of truncated and untruncated structures. This segmentation allows independent optimization of each layer's structural characteristics while collectively achieving enhanced brightness through multiple light redirection events, with each layer contributing additively to the overall optical performance.
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 optical stack enhances display brightness by reducing light distortion while maintaining high transmission efficiency for both visible and infrared wavelengths, enabling effective fingerprint detection.
Implementation Method 1
Each truncated first structure has opposing side surfaces making an angle of between about 60 degrees to about 120 degrees with each other and a substantially planar top surface joining the opposing side surfaces
Implementation Method 2
the reflecting layer may reflect at least 70% of the incident light for each wavelength in a human-visible wavelength range, and may transmit at least 70% of the incident light for the at least one wavelength in an infrared wavelength range
Data Source
AI summary
An optical stack includes stacked first and second light redirecting layers, each light redirecting layer including a plurality of truncated first structures, each truncated first structure with opposing side surfaces making an angle of between about 60 degrees to about 120 degrees with each other and a substantially planar top surface joining the opposing side surfaces, and a plurality of untruncated second structures, each untruncated second structure with opposing side surfaces making an angle of between about 60 degrees to about 120 degrees with each other and meeting at peak, wherein the peaks of the untruncated second structures and the substantially planar top surfaces of the first truncated structures substantially lie in the same plane.