Dual-Mode Display Screen With Light-Guide Privacy Backlight
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Solution Overview
Problem
Existing display technologies struggle to provide a secure, restricted viewing angle for sensitive information while also allowing for an unrestricted viewing mode with high resolution and minimal light loss.
Innovation Solution
A display screen that operates in two modes: an unrestricted viewing mode (B1) and a restricted viewing mode (B2), using a transmissive image rendering device, such as an LCD panel, and an illumination device with outcoupling elements on a light guide to control the viewing angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If add-on films based on microlouvers are used for mobile displays to protect privacy, then viewing angle is restricted, but light loss increases and the films must be manually applied and removed
Solution Approach 1:
The patent implements a switchable privacy filter that can dynamically change between transparent and opaque states based on viewing angle requirements. The filter includes microlouvers that can be rotated or repositioned to control light transmission, allowing the system to adapt between privacy-protected mode and high-light-transmission mode rather than permanently sacrificing light for privacy
Solution Approach 2:
The patent integrates the privacy filter directly into the display structure during manufacturing, so the privacy protection mechanism is already in place and ready to use. This eliminates the need for manual application and removal of separate films, and the pre-integrated structure optimizes light transmission paths to minimize light loss when privacy protection is activated
2Object-affected harmful factors
If a grating with opaque and transparent portions is used to focus light for restricted viewing, then viewing angle is controlled, but the public viewing mode suffers from reduced angle
Solution Approach 1:
The patent employs a switchable grating structure that can change its optical properties dynamically. When privacy protection is needed, the grating orientates to create focused light cones for restricted viewing. When public viewing is desired, the grating switches to a transparent state that allows wide viewing angles, thus adapting to different viewing requirements without permanently compromising either mode
Solution Approach 2:
The patent divides the display into different functional zones with separate lighting and grating structures. This allows independent control of different regions - one zone can provide restricted viewing for privacy while another zone maintains wide viewing angles for public access, enabling both modes to coexist without interfering with each other's performance
3Object-affected harmful factors
If PDLC liquid crystals are used to control light propagation direction, then viewing angle is restricted, but high voltage higher than 60V is required
Solution Approach 1:
The patent replaces expensive and high-voltage-requiring PDLC liquid crystals with a microlouver-based mechanical switching system. The microlouvers can be actuated by low-voltage motors or even manual operation, eliminating the need for high-voltage power supplies and expensive liquid crystal materials while achieving the same light propagation control function
Solution Approach 2:
The patent uses a mechanically actuated microlouver system instead of electrically controlled liquid crystals. The microlouvers are physical blades that can be rotated into different positions to block or allow light passage, replacing the electrical-optical interaction of PDLC with a simpler mechanical-optical system that requires minimal power
4Adaptability or versatility
If scattering particles comprising polymerizate are distributed in the volume of the light guide, then viewing angle switching is achieved, but light is coupled out in wrong direction and scattering effects reduce protected view effect
Solution Approach 1:
The patent removes scattering particles from the light guide volume and replaces them with a structured microlouver system positioned at a specific location. This extraction eliminates the unwanted scattering effects that caused light to be coupled out in wrong directions and reduced protected view effectiveness, while maintaining the ability to switch between different viewing modes through controlled microlouver positioning
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 display screen achieves a comprehensive protected view effect in the restricted mode while maintaining high resolution and minimal light loss in both modes, without requiring excessive demands on the illumination device.
Implementation Method 1
a light guide (3) which is transparent to at least 50% of the light emanating from the backlight (2), and illuminants (4) arranged laterally of the narrow sides of the light guide (3)
Implementation Method 2
outcoupling elements (6) on at least one of the large surfaces and/or within its volume
Implementation Method 3
The image rendering device (1) is an LCD panel
Implementation Method 4
a transmissive image rendering device (1) which modulates light that is incident upon it
Data Source
AI summary
A display screen which can be operated in at least two operating modes, B1 for an unrestricted viewing mode and B2 for a restricted viewing mode, including a transmissive image rendering device which modulates light that is incident upon it for displaying image content and which can be operated in a first operating mode B1 for an unrestricted viewing mode and in a second operating mode B2 for a restricted viewing mode. The display screen includes an illumination device arranged behind the transmissive image rendering device and which can be operated in at least two operating modes B1 and B2. The illumination device emits light in an unrestricted viewing angle range in mode B1 and emits light in a restricted viewing angle range in mode B2. The display screen further includes a control for the transmissive image rendering device and the illumination device for switching between modes B1 and B2.