Under Display Sensor Depolarization for Polarized Eyewear
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Solution Overview
Problem
Mobile devices with polarized screens and sunglasses experience difficulties in maintaining clear visibility when rotated from portrait to landscape mode due to cross-polarization, leading to dark or black screens and degraded image quality.
Innovation Solution
Incorporating a sensing device with optical elements such as a first and second optical retardance element, a polarizing element, and a reflective element, which depolarize light to allow it to be sensed by a sensor array, enabling clear visibility regardless of orientation and mitigating optical artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a polarizing layer is used in the display screen, then the screen visibility is improved in portrait mode, but the screen becomes dark or black in landscape mode when viewed through polarized sunglasses
Solution Approach 1:
The optical stack is divided into multiple functional segments: a polarizing layer for initial polarization, a first depolarization layer with high retardance (≥8000nm) for depolarizing reflected light, and a second depolarization layer with lower retardance (100-1000nm) for fine-tuning polarization states. This segmentation allows each layer to address specific aspects of the polarization problem independently.
Solution Approach 2:
The patent changes the polarization state parameters of light through the optical stack. The high-retardance depolarization layer transforms linearly polarized light into depolarized light by introducing a retardance parameter ≥8000nm, while the low-retardance layer provides additional parameter adjustment. This enables the screen to maintain visibility across different orientations and viewing conditions.
2Object-affected harmful factors
If polarized lenses are used in sunglasses, then glare reduction is improved, but the ability to view the screen in all orientations is degraded
Solution Approach 1:
The patent converts the harmful effect of polarized sunglasses blocking screen visibility into a beneficial feature by incorporating depolarization layers that actively counteract the polarization. The high-retardance layer transforms the polarized light from the display into depolarized light, which then passes through the user's polarized sunglasses without being blocked, effectively converting the sunglasses' polarization-filtering property from a hindrance to a compatible feature.
Solution Approach 2:
The optical stack acts as an intermediary between the display screen and the user's polarized sunglasses. The depolarization layers modify the light's polarization state to be compatible with both the screen's polarizing layer and the user's polarized lenses, serving as a mediator that reconciles the conflicting polarization requirements.
3Adaptability or versatility
If multiple optical layers are added to the display stack, then viewing compatibility is improved, but the device complexity increases
Solution Approach 1:
The optical stack is designed with multi-functionality: the high-retardance depolarization layer serves both as a depolarization element for reflected light and as a polarization controller for emitted light, while the low-retardance layer provides additional polarization adjustment. This multi-functionality reduces the need for separate dedicated components for each function, thereby managing complexity while maintaining versatility.
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
Enables users to view mobile device screens in any orientation while wearing polarized eyewear, maintaining image quality and allowing biometric data sensing, such as fingerprint recognition, without the need to remove sunglasses.
Implementation Method 1
a first optical retardance element which may be configured to receive depolarized light from the reflective element along an optical path... where the first optical retardance element has a higher retardance than the second optical retardance element
Implementation Method 2
a reflective element... configured to receive depolarized light to transmit to the polarizing element and to receive depolarized and reflected light from a finger of the user along the optical path
Implementation Method 3
a sensor array which may be configured to receive light along the optical path... the sensor array may be further configured to sense light used to determine physiological information of a user
Data Source
AI summary
An optical system is described. The optical system may include a sensor which may be in a mobile device. The optical system may use the same light source for imaging the display and for providing light to a sensor or sensor device. The optical system may be configured so that randomly polarized light will exit the device for viewing so that a user may view the display in any rotated orientation while wearing polarized eyewear. The optical system may further be configured to mitigate reflections in the mobile device from ambient light entering the system and from reflected and backscattered light from cross-contaminating the imaging light of the display.