Switchable Optical Element for Display Privacy Without Light Loss
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Solution Overview
Problem
Current display technologies face challenges in switching between public and private viewing modes without significant light loss, complexity, or reduction in brightness, especially in achieving a wide viewing angle with limited angular range in private mode.
Innovation Solution
A two-dimensionally extensive optical element with alternating regions of different refractive indices, featuring opaque layers that control light propagation directions, allowing switching between public and private modes with minimal brightness reduction and universal applicability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If microlouver films are used for private viewing mode, then viewing privacy is improved, but light loss increases and the films cannot be switched dynamically
Solution Approach 1:
The patent implements dynamic switching between public and private viewing modes using an optical element with switchable light propagation characteristics. The optical element can transition between different states (e.g., via liquid crystal reorientation or mechanical adjustment) to control light direction, enabling the display to switch from wide viewing angle to restricted viewing angle on demand, unlike static microlouver films
Solution Approach 2:
The patent replaces the mechanical mounting and manual application/removal of microlouver films with an integrated optical element that uses optical principles (such as liquid crystal orientation changes or prismatic structures) to achieve mode switching. This eliminates the need for mechanical attachment and removal mechanisms
2Object-affected harmful factors
If complex optical elements like microlens elements and prism structures are used to transform light, then viewing angle control is improved, but device complexity and light losses increase
Solution Approach 1:
The patent combines the light transformation function and viewing angle control function into a single integrated optical element. Rather than using separate microlens elements and prism structures as described in prior art, the invention integrates these functions into one component that can be positioned directly at the display surface, reducing overall device complexity while maintaining effective viewing angle control
Solution Approach 2:
The optical element is designed to perform multiple functions: it controls viewing angles, transforms light propagation directions, and enables dynamic switching between public and private modes. This multi-functional design eliminates the need for multiple separate optical components, simplifying the overall display structure
3Object-affected harmful factors
If complex light transformation is used to achieve viewing angle control, then private mode effectiveness is improved, but brightness is reduced
Solution Approach 1:
The patent controls light propagation by changing optical parameters such as the orientation of liquid crystal molecules or the angular configuration of prismatic structures, rather than using complex multi-stage light transformation. This approach maintains higher brightness levels while achieving effective private mode viewing by directing light at specific angles rather than absorbing or scattering it through multiple transformations
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 optical element effectively limits light propagation directions, enabling a top hat light distribution with minimal brightness decrease, allowing for seamless switching between public and private viewing modes without compromising display resolution or increasing complexity.
Implementation Method 1
first regions B1 comprising at least a first transparent material with a first refractive index N1 and second regions B2 comprising a second transparent material with a second refractive index N2 which alternate over the surface of the first optical element 1 in a one-dimensional or two-dimensional periodic sequence, the first refractive index N1 being higher than the second refractive index N2 within the entire wavelength range visible to the human eye
Implementation Method 2
Depending on the incident angle, polarization and the ratio of the first refractive index N1 to the second refractive index N2, light which has impinged on the optical element 1 on the light entry side a) propagates unimpeded or is totally internally reflected inside of a first region B1 and is thereafter coupled out again at a light exit surface of the corresponding first region B1
Data Source
AI summary
A two-dimensionally extensive optical element having a light entry side and a light exit side. The optical element includes alternating transparent first regions and second regions having materials with different first refractive indices and second refractive indices. The first refractive index is higher than the second refractive index. First layers and second layers which are opaque or are switchable to be opaque are arranged at the light entry surfaces and light exit surfaces of the second regions. When the layers are opaque, the propagation directions of light passing through the optical element are limited compared to layers which are switched to be transparent.