Transparent Projection Screen with Polarized Behind-Display Camera Filtering
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Solution Overview
Problem
Conventional display screens are not sufficiently transparent and obstruct the view when a camera is placed behind them, causing issues with light reflection, ghost images, and Moiré patterns, which degrade the video conferencing experience by preventing eye-to-eye contact and misaligning the presenter's gaze with digital content.
Innovation Solution
A system comprising a transparent display screen with a series of optical layers, including orthogonal linear polarizers and a projector synchronized with a rolling shutter camera, to block projected images from being captured by the camera while allowing ambient light to pass through, and using a dispersion layer to ensure clear image capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a camera is placed behind the display screen to achieve unobstructed eye-to-eye contact, then the video conferencing naturalness is improved, but the display screen transparency is insufficient causing ghost images and Moiré patterns
Solution Approach 1:
The patent introduces an optical layer as an intermediary between the display screen and the camera. This optical layer selectively transmits certain wavelengths of light while blocking others, thereby preventing ghost images and Moiré patterns from reaching the camera sensor while maintaining the behind-screen camera configuration for natural eye-to-eye contact
Solution Approach 2:
The patent changes the optical parameters of the display system by introducing an optical layer with specific transmission characteristics. This layer modifies the light spectrum passing through the display, blocking specific wavelengths that cause ghost images and Moiré patterns while allowing other wavelengths to pass through for normal display functionality
2Ease of operation
If the camera is positioned at the front center of the screen to achieve unobstructed view, then the eye-to-eye contact is improved, but the displayed content is blocked
Solution Approach 1:
Instead of placing the camera at the front where it would block the display, the patent inverts the camera position to the back of the display screen. This allows the camera to capture the presenter's face through the transparent display without obstructing the displayed content from the viewer's perspective
3Illumination intensity
If a transparent OLED display with 40% transparency is used to improve light transmission, then the camera capture quality is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
Rather than relying solely on expensive transparent OLED technology with complex manufacturing processes, the patent introduces an optical layer as a simpler intermediary component. This optical layer can be applied to conventional displays and achieves the desired light transmission and ghost image suppression without requiring complex transparent OLED manufacturing
Solution Approach 2:
The patent modifies the optical parameters of the display system by adding an optical layer with specific transmission properties. This approach achieves improved light transmission and ghost image suppression through parameter modification rather than through complex manufacturing process changes required for transparent OLED displays
4Ease of manufacture
If conventional display screens are used to maintain simplicity, then the manufacturing cost is reduced, but the transparency is insufficient causing the camera to capture displayed content
Solution Approach 1:
The patent introduces an optical layer as an intermediary component that can be applied to conventional display screens. This layer selectively blocks the transmission of projected image light to the camera while maintaining the overall simplicity and low cost of conventional display manufacturing
Solution Approach 2:
The patent modifies the optical parameters of conventional display screens by adding an optical layer with specific transmission characteristics. This changes the light transmission properties to prevent projected image capture by the camera while maintaining manufacturing simplicity and cost-effectiveness
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 effectively removes ghost images and Moiré patterns, allowing for a natural video conferencing experience with the presenter's gaze aligned with digital content, enhancing user interaction and clarity.
Implementation Method 1
a first linear polarizer, a partially reflective layer or dispersion layer, and a second linear polarizer. The first and second linear polarizers are orthogonal to one another, i.e., their axes are oriented 90 degrees to one another to block the projected image from being received by the camera
Implementation Method 2
a partially reflective layer or dispersion layer
Data Source
AI summary
A system for video conferencing comprises a video projector and a transparent projection screen of clear material. A behind-display camera captures a video image through the transparent projection screen of a user located on the front side of the screen. To optimize the brightness of the projected video image (as viewed by the user) while preventing the behind-display camera from capturing that same projected video image transmitted through the screen, a series of optical layers in the form of films and/or coatings are included in the optical path between the projector and the camera. The series of optical layers may comprise a first linear polarizer, a partially reflective layer or dispersion layer, and a second linear polarizer. The first and second linear polarizers are orthogonal to one another, i.e., their axes are oriented 90 degrees to one another to block the projected image from being received by the camera. In a front projection arrangement, the partially reflective layer is designed to reflect a bright projected image to the user while permitting ambient light on the user's side to transmit to the camera. In a rear projection arrangement, the dispersion layer is designed to transmit a bright projected image to the user while permitting ambient light on the user's side to transmit through to the camera.