Dual Backlight Display Screen with Light Guide for Viewing Mode Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing display technologies fail to efficiently switch between wide and narrow viewing angles on a display screen without significant light loss, complexity, or increased cost, and cannot selectively restrict viewing on part of the screen.
Innovation Solution
A display screen with two backlights, one for a non-restricted and one for a restricted angular range, combined with a transparent light guide and lateral light sources, allowing for switching between modes with minimal light loss and maintaining high resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If accessory films based on micro-louvers are used to provide optical data protection, then viewing angle restriction is achieved, but light loss occurs and the films cannot be switched between modes
Solution Approach 1:
The patent applies dynamics by making the light guide switchable between different optical states. The light guide can be configured to guide light in wide angles for free viewing mode or in narrow angles for restricted viewing mode, enabling dynamic adaptation to different privacy requirements without permanent structural changes or manual film attachment.
Solution Approach 2:
The patent changes the optical parameters of the light guide by controlling the emission angles of the backlight units. By adjusting the angular distribution of light from the backlights, the system can switch between wide viewing angle mode and narrow viewing angle mode, resolving the contradiction between viewing restriction and light loss.
2Adaptability or versatility
If two backlights are used to provide both wide and narrow illuminating angles, then viewing mode switching is enabled, but device complexity increases
Solution Approach 1:
The patent merges the two backlight units into a single integrated light guide structure. The first and second backlights are combined within the same light guide, allowing them to work together as a unified system rather than separate components, thereby reducing overall device complexity while maintaining the capability to provide both wide and narrow illuminating angles.
Solution Approach 2:
The light guide serves multiple functions: it guides light from both backlights, provides the switching mechanism between viewing modes, and acts as the optical element that determines the final emission angle. This multi-functionality reduces the need for additional separate components, simplifying the overall device structure.
3Object-affected harmful factors
If light is converted from narrow illuminating angle to wide illuminating angle using partial mirrors, then viewing angle is expanded, but light intensity is greatly reduced
Solution Approach 1:
The patent replaces the mechanical partial mirror system with a light guide-based optical control mechanism. Instead of using mirrors to redirect and spread light (which causes significant intensity loss), the light guide uses total internal reflection and controlled emission to achieve angle conversion while preserving light intensity through optimized optical pathways.
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 seamless switching between free and restricted viewing modes on a display screen with minimal light loss and high resolution, suitable for applications like vehicle entertainment and secure data entry, while being cost-effective and easy to implement.
Implementation Method 1
a light guide (3), which is designed in such a way that it outcouples, through at least one of its large surfaces, light fed through at least one of its narrow sides (edges)
Implementation Method 2
the light guide (3) is transparent to at least 70%, preferably at least 85%, of the light emitted by the backlights
Data Source
AI summary
A display screen operable on at least a partial area A in two operating modes, free-viewing mode B1, and restricted-viewing modeB2, with the residual display area of the screen outside the area A maintaining a free viewing mode; comprising a first backlight arranged below the residual display area; a second backlight arranged below the area A; a transmissive image generator in front of the backlights; a plate-shaped transparent light guide arranged between the image generator and the backlights that outcouples, through one of its large surfaces, light coupled in through one of its edges; light sources arranged laterally an edge of the light guide, wherein the light guide is transparent to at least 70% of the light emitted by the backlights, and wherein in the B1 mode, the light sources are switched on, and in the B2 mode, the backlights are on and the light sources are off.