Backlight Light Expander Structures for Uniform Illumination
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Solution Overview
Problem
Conventional backlight assemblies for displays, particularly in head-mounted displays, face inefficiencies in providing uniform and bright light, which can impact the quality of virtual and augmented reality experiences due to limitations in light distribution and energy consumption.
Innovation Solution
The implementation of a backlight assembly that incorporates beam expander structures, comprising a first and second light expander structure with reflective polarizer and wave retarder layers, which expand a collimated beam of light in multiple dimensions to create a uniform surface light source, enhancing light distribution and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional backlight assemblies are used in head-mounted displays, then the display can be illuminated, but the light distribution is non-uniform and power consumption is high
Solution Approach 1:
The patent transforms a one-dimensional linear light source into a two-dimensional surface light source by implementing beam expander structures that expand light in both vertical and horizontal dimensions. This dimensional transformation enables uniform light distribution across the display panel while reducing the required light source power, directly resolving the contradiction between illumination uniformity and power consumption
Solution Approach 2:
The patent introduces beam expander structures with reflective polarizer layers and wave retarder layers as intermediary optical elements between the light source and display panel. These intermediaries manipulate light propagation to achieve uniform illumination without requiring higher power consumption, mediating between the light source and display to resolve the contradiction
2Illumination intensity
If conventional backlight assemblies are used, then light can be provided to the display, but the overall assembly thickness is large
Solution Approach 1:
By expanding light from a linear source into a two-dimensional surface source through controlled optical manipulation, the patent reduces the need for thick conventional backlight structures. The beam expander structures achieve uniform illumination across the display area while maintaining a slim profile, resolving the contradiction between brightness and assembly thickness
Solution Approach 2:
The patent changes the optical parameters of light propagation by using reflective polarizer layers and wave retarder layers to control light direction and distribution. This parameter manipulation enables thin-form-factor backlight assemblies to achieve high brightness and uniform illumination, resolving the contradiction between brightness and thickness
3Speed
If a collimated beam of light is used from the light source, then light direction can be controlled, but the light distribution across the display is non-uniform
Solution Approach 1:
The patent takes collimated light traveling in one direction and expands it into two dimensions through beam expander structures. The reflective polarizer and wave retarder layers manipulate the expanded light to achieve uniform distribution across the display panel, resolving the contradiction between light propagation control and distribution uniformity
Solution Approach 2:
The beam expander structures with reflective polarizer layers and wave retarder layers serve as intermediary optical elements that receive collimated light and transform it into uniformly distributed illumination. These intermediaries maintain directional control while achieving uniform distribution, resolving the contradiction between propagation control and uniformity
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
This solution results in a more efficient and uniform light distribution, reducing power consumption and enabling slimmer display designs while maintaining high brightness and appropriate color characteristics, thereby improving the overall display performance and user experience in virtual and augmented reality applications.
Implementation Method 1
a first reflective polarizer layer and a first wave retarder layer that cooperate to redirect a collimated beam of light in a first direction
Implementation Method 2
a first reflective polarizer layer and a first wave retarder layer that cooperate to redirect a collimated beam of light
Implementation Method 3
a second reflective polarizer layer and a second wave retarder layer that cooperate to redirect the collimated beam of light in a second direction that is perpendicular to the first direction
Data Source
AI summary
Methods and systems relating generally to information displays, and more particularly to systems and methods for backlight assemblies for information displays that include light expanding structures. A backlight assembly may include light expander structures that include a plurality of layer sets, wherein each layer set includes a reflective polarizer layer and a wave retarder layer. The layer sets may together be operative transform point light source, such as a laser light beam, into a surface light source for use as a backlight for various types of information displays.