Edgelit Light Guide with Asymmetric Patterns for Restricted Viewing Angles
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Solution Overview
Problem
Conventional display devices lack the ability to restrict viewing angles, which can be a safety concern in situations like vehicle use, where drivers need to focus on the road without distractions, while passengers should have access to the display.
Innovation Solution
A backlight unit comprising multiple light source packages and a light guide plate with asymmetric patterns that control light emission to limit viewing angles, allowing for different viewing modes by adjusting the inclination angles and positions of these patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional display devices are used with wide viewing angles, then image quality and visibility are improved for multiple viewers, but driver safety deteriorates due to unrestricted viewing angles allowing distracted viewing
Solution Approach 1:
The patent applies dynamics by making the viewing angle adjustable rather than fixed. The light guide plate can switch between different light extraction patterns (first pattern for wide viewing angle, second pattern for restricted viewing angle) based on driving conditions. This dynamic adjustment allows the display to adapt between wide viewing angle mode for passenger entertainment and restricted viewing angle mode for driver safety, resolving the contradiction between versatility and reliability.
Solution Approach 2:
The patent changes the light extraction parameter by using different patterns on the light guide plate. The first light extraction pattern allows light to be extracted at wider angles for passenger viewing, while the second light extraction pattern restricts light extraction to narrower angles for driver safety. By changing this optical parameter based on usage scenario, the system simultaneously achieves both wide viewing angle capability and driver safety protection.
2Reliability
If the viewing angle is restricted to enhance driver safety, then driver distraction is reduced, but passenger access to display content deteriorates
Solution Approach 1:
The system dynamically switches between two operational modes: a driver safety mode with restricted viewing angles and a passenger entertainment mode with wide viewing angles. The controller adjusts the light extraction pattern based on whether the vehicle is in driving mode or entertainment mode, ensuring that passenger access is maintained when needed while prioritizing driver safety when the vehicle is in motion.
Solution Approach 2:
The patent implements periodic switching between different light extraction patterns based on driving conditions. During active driving, the system uses the second light extraction pattern to restrict viewing angles for safety. When the vehicle stops or enters entertainment mode, it switches to the first light extraction pattern to provide wide viewing angles for passengers. This periodic action between different operational states resolves the contradiction between driver safety and passenger access.
3Device complexity
If a single light extraction pattern is used in the light guide plate, then device complexity is reduced, but the ability to dynamically adjust viewing angles deteriorates
Solution Approach 1:
The light guide plate is segmented into different regions with different light extraction patterns. The first light extraction pattern is positioned to provide wide viewing angles for passenger areas, while the second light extraction pattern is positioned to restrict viewing angles in driver areas. This segmentation allows a single light guide plate to provide multiple viewing angle configurations without requiring multiple separate components, thus maintaining simplicity while achieving adaptability.
Solution Approach 2:
The light guide plate is designed with multi-functionality by incorporating both the first light extraction pattern and the second light extraction pattern within a single component. This universal design allows the same light guide plate to serve dual purposes: providing wide viewing angles when needed and restricting viewing angles when safety is prioritized. This eliminates the need for multiple separate light guide plates or complex mechanical adjustment mechanisms.
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 restricts side viewing angles to enhance driver safety by limiting distractions while allowing passengers to view content, and can dynamically switch between wide and narrow viewing angles based on user needs or driving conditions.
Implementation Method 1
The light incident from the first light source package to the light guide plate may be refracted by the first inclined surface of the first patterns and emitted through a top surface in the first area
Data Source
AI summary
A display includes a display panel; and a backlight unit with a first light source package, a second light source package facing towards the first light source package, and a light guide plate disposed between the first light source package and the second light source package. The light guide plate includes first and second patterns protruding from a bottom surface of the light guide plate, the patterns including at least one inclined surface with respect to the bottom surface of the light guide plate, the inclined surface facing towards a corresponding one of the first light source package or the second light source package.