Switchable Privacy Backlight With Barrier Slit And Lens Array
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Solution Overview
Problem
Current automotive display systems fail to achieve a strong privacy mode while maintaining sufficient brightness in both private and public viewing modes due to insufficient light efficiency and residual off-axis light transmission.
Innovation Solution
A switchable privacy display system incorporating a reflective barrier and slit structure combined with a lens array, along with a hydrodynamic hybrid-aligned nematic (HHAN) liquid crystal cell, which enhances privacy in a narrow viewing angle mode and scatters light for a wide viewing angle mode, achieving improved light efficiency and brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a Louvre film is used for view angle control, then privacy mode is achieved, but light efficiency is low and public mode appears dim
Solution Approach 1:
The view angle control function is divided into two separate components: a Louvre film for privacy mode and a switchable scattering layer for public mode. This segmentation allows each component to be optimized for its specific function, with the Louvre film providing strong off-axis light blocking and the scattering layer providing wide-angle light diffusion when activated.
Solution Approach 2:
The scattering layer is made switchable, allowing the display to dynamically transition between privacy mode (Louvre film only) and public mode (Louvre film + activated scattering layer). This dynamic capability enables the system to adapt to different viewing requirements while maintaining high light efficiency in both modes.
2Object-affected harmful factors
If a switchable scattering LCD is added to enhance privacy mode, then off-axis light is blocked, but device complexity increases
Solution Approach 1:
The scattering layer is implemented as a thin film structure that can be integrated into the existing display stack. This thin film approach enhances privacy functionality without significantly increasing device complexity or thickness, as the scattering particles are embedded within a thin polymer or liquid crystal matrix.
3Adaptability or versatility
If light is scattered to wider angles for public mode, then viewing angle is improved, but brightness is reduced
Solution Approach 1:
The Louvre film is positioned to pre-collimate the backlight light before it reaches the scattering layer. This preliminary collimation ensures that when the scattering layer is activated, it scatters already-directional light rather than omnidirectional light, maximizing light efficiency while achieving wide viewing angles in public mode.
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 system provides a strong private mode with enhanced brightness in both modes, significantly surpassing conventional configurations by recycling light and optimizing light transmission, ensuring compliance with automotive safety standards.
Implementation Method 1
a lens array of lens elements located on a viewing side of the barrier and slit structure, with the lens elements being located in a separate plane relative to the barrier regions, wherein the barrier and slit structure and the lens array operate to transmit light from the backlight unit collimated in a limited viewing angle range
Implementation Method 2
the barrier regions are reflective barrier regions that recycle light emitted from the backlight unit
Implementation Method 3
a hydrodynamic hybrid-aligned nematic (HHAN) liquid crystal cell, which in a first mode enhances the privacy of the display device, and in a second mode scatters the previously collimated light off-axis to provide the public mode
Data Source
AI summary
A display component controls a viewing angle in a display system that achieves a strong private mode and enhanced brightness in the private and public modes as compared to conventional configurations. A display system that is operable in the private mode and the public mode includes the display component in combination with an image panel. The display component includes a backlight unit that emits light from a non-viewing side of the display component toward a viewing side of the display component; a barrier and slit structure located on a viewing side of the backlight unit, the barrier and slit structure comprising a plurality of opaque barrier regions interspersed with a plurality of transparent slit regions; and a lens array of lens elements located on a viewing side of the barrier and slit structure, with the lens elements being located in a separate plane relative to the barrier regions, wherein the barrier and slit structure and the lens array operate to transmit light from the backlight unit collimated in a limited viewing angle range.