Dual Backlight Display Unit for Selective Visibility Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Display devices in vehicles and portable devices face challenges in maintaining confidentiality of information displayed, as it can be visible to unintended users, and information intended for passengers may distract drivers, requiring a solution to control visibility selectively.
Innovation Solution
A display device with a screen having controllable optical transmission and a dual backlight system, where the first backlight emits light with a reduced angular width to a specific field, and the second backlight emits light with a wider angular field, allowing selective visibility to users based on their position, controlled electrically without mechanical movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If a single backlight assembly illuminates the entire screen, then all users in the vicinity can view the displayed information, but information confidentiality is compromised and unintended users (such as drivers) may be distracted
Solution Approach 1:
The single backlight assembly is divided into two independent backlight assemblies (first and second backlight assemblies), each capable of independently illuminating the screen. This segmentation allows selective activation of different backlight assemblies to control which users can view the displayed information, thereby maintaining confidentiality while avoiding the need for complex mechanical moving parts.
Solution Approach 2:
The system dynamically switches between different backlight assemblies based on operational context. The control unit selectively activates the first backlight assembly for driver-assistance information or the second backlight assembly for entertainment content, enabling adaptive control of information visibility without mechanical movement.
2Ease of operation
If the screen displays information visible to all nearby users, then accessibility is improved, but driver distraction and safety risks increase
Solution Approach 1:
The backlight system is segmented into two independent assemblies with different illumination characteristics. The first backlight assembly provides wide-angle illumination for driver visibility, while the second provides narrow-angle illumination for passenger entertainment, allowing information to be selectively accessible to different user groups without causing driver distraction.
Solution Approach 2:
Different regions of the passenger compartment are provided with different illumination characteristics. The first backlight assembly directs light toward the driver's position for critical information, while the second directs light toward passenger positions for entertainment content, creating localized viewing zones that prevent driver distraction while maintaining accessibility for intended users.
3Loss of information
If a privacy filter is used to restrict viewing angle, then information confidentiality is improved, but overall visibility and brightness are reduced
Solution Approach 1:
Instead of using a static privacy filter that reduces overall brightness, the system dynamically selects between two backlight assemblies with different illumination characteristics. The control unit activates the appropriate backlight assembly based on the type of information being displayed, maintaining high brightness levels while controlling viewing angles through selective activation rather than optical filtering.
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 secure display of information by restricting visibility to intended users and controlling the visibility of critical driving information to prevent driver distraction, enhancing confidentiality and safety.
Implementation Method 1
the light guide being made using a plate at least partially transparent, the at least partially transparent plate of the second backlighting system allows the first light radiation emitted by the first backlighting system to pass through, at least in part
Implementation Method 2
a second light source arranged around the periphery of the plate, the light guide being configured so that a second light beam received from the second light source exits at least partially from said plate towards the screen
Implementation Method 3
the first backlighting assembly includes an imposing optical filter on the first light radiation, said reduced angular width
Implementation Method 4
the display device includes a polarization recycling filter positioned between the second backlight assembly and the screen's input face
Data Source
AI summary
The invention relates to a display unit (10) comprising: a screen (13) having controllable optical transmission and a first backlighting assembly (11) configured to emit first light radiation towards the screen so as to illuminate a first field of illumination after transmission by the screen. According to the invention, the display unit comprises a second backlighting assembly (12), situated between the screen and the first backlighting device and comprising: a light guide produced by means of an at least partially transparent plate (122), and a second light source (112) arranged on the periphery of the plate, the light guide being configured in such a way that second light radiation received from the second light source exits at least partly from said plate in the direction of the screen in order to illuminate, after passing through the screen, a second field of illumination at least partially separate from the first field of illumination.