Directional Display Privacy Control via Dynamic Viewing Window
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Solution Overview
Problem
Existing directional display devices lack effective privacy control mechanisms that distinguish between primary and secondary viewers, often blurring the image for everyone, including the primary user, when attempting to prevent unwanted viewing.
Innovation Solution
A directional display device with a transmissive spatial light modulator and adjustable directional backlight, capable of detecting secondary viewers and adjusting the viewing window's width and position to ensure only the primary viewer can see the image, using a combination of image analysis, electromagnetic tags, and location sensors to determine viewer permissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the displayed image is blurred to prevent secondary viewers from seeing it, then privacy protection is improved, but the primary viewer's ability to view the image is degraded
Solution Approach 1:
The patent applies local quality by directing light into a specific viewing window in front of the display device. This creates a localized region where the image is visible to the primary viewer while remaining obscured to secondary viewers from other angles. The directional backlight selectively illuminates only the intended viewing area, providing privacy protection without degrading the primary viewer's experience.
Solution Approach 2:
The patent segments the viewing experience by creating a distinct viewing window separated from the rest of the display area. The directional backlight divides the light distribution into a focused viewing cone, effectively segmenting the image visibility so that only viewers within the specific angular range can see the content clearly, while others see only a blurred or obscured version.
2Object-affected harmful factors
If the viewing window width is reduced to prevent shoulder surfing, then privacy protection is improved, but the viewing comfort for the primary user is degraded
Solution Approach 1:
The patent applies dynamics by making the viewing window adjustable rather than fixed. The system can dynamically modify the width and position of the viewing window based on the detected presence and position of secondary viewers. This allows the viewing window to adapt to different viewing scenarios, maintaining privacy protection while optimizing viewing comfort for the primary user in real-time.
Solution Approach 2:
The patent implements feedback by using sensors to detect the presence and position of viewers, then using this information to adjust the directional backlight's viewing window. The system continuously monitors the viewing environment and modifies the light direction and window parameters accordingly, creating a closed-loop control system that balances privacy protection with viewing comfort based on actual conditions.
3Device complexity
If a fixed directional backlight is used to create a viewing window, then device complexity is reduced, but adaptability to different viewing scenarios is degraded
Solution Approach 1:
The patent applies universality by designing a directional backlight system that can perform multiple functions: creating a fixed viewing window for basic privacy, dynamically adjusting the viewing window width and position for adaptive privacy, and responding to different viewing scenarios. This multi-functional approach allows the same hardware to serve both simple and complex privacy needs without requiring separate systems.
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 solution effectively reduces the visibility of the displayed image to secondary viewers while maintaining visibility for the primary user, enhancing privacy control by dynamically adjusting the viewing window based on detected viewers and their permissions.
Implementation Method 1
a waveguide arranged to direct light from the light sources into respective optical windows in the viewing plane
Implementation Method 2
a transmissive spatial light modulator capable of displaying a displayed image
Data Source
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AI summary
A directional display apparatus including a directional display device that is capable of directing a displayed image into a viewing window of variable width is provided with a privacy control function. A control system detects the presence of one or more secondary viewers in addition to a primary viewer, and decides whether the one or more secondary viewers is permitted to view the displayed image. The control system directs a displayed image into a viewing window which is adjusted, for example by decreasing the width, in dependence on that detection. In addition, the control system detects relative movement between the primary viewer and the display device, and the width of the viewing window is increased in response to detection of said relative movement.