Active Zonal Display Illumination Using Chopped Lightguide
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Solution Overview
Problem
There is a need for compact and lightweight head-mounted display devices that provide uniform illumination for enhanced user experience in virtual and augmented reality operations, while reducing power consumption and battery size and weight.
Innovation Solution
The use of an optical device with a substrate and optical elements that redirect and modulate light polarization, combined with switchable cells containing optically anisotropic molecules, allows for efficient zonal illumination of a reflective spatial light modulator, reducing the need to illuminate the entire surface and improving energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the entire surface of the display element is illuminated, then uniform illumination is achieved, but power consumption increases
Solution Approach 1:
The display surface is divided into multiple independently controllable zones. Each zone can be illuminated separately based on display requirements, allowing selective activation of only necessary regions rather than illuminating the entire surface uniformly.
Solution Approach 2:
The illumination system transitions from static full-surface illumination to dynamic zonal illumination. The illumination state of each zone can be changed in real-time based on display content requirements, enabling the system to adapt illumination patterns dynamically.
2Illumination intensity
If higher power consumption is accepted, then illumination quality improves, but battery size and weight increase
Solution Approach 1:
Instead of providing full illumination across the entire display surface, the system applies illumination only to the specific zones that require it. This partial action maintains sufficient illumination quality for display purposes while significantly reducing the total power consumption.
3Use of energy by moving object
If zonal illumination is implemented, then power consumption reduces, but device complexity increases
Solution Approach 1:
Different regions of the display surface are assigned different illumination characteristics. Each zone can have independent illumination control, allowing the system to optimize power consumption by activating only the zones that require illumination based on display content.
4Volume of moving object
If compact design is pursued, then device size reduces, but illumination uniformity may compromise
Solution Approach 1:
The illumination system is segmented into multiple zones that can be independently controlled. This segmentation allows the compact optical elements to be strategically positioned to illuminate specific zones uniformly without requiring full-surface illumination, thus maintaining illumination quality while reducing device size.
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 approach results in lightweight, compact display devices with high-quality images, extended operational time, and reduced battery size and weight, achieving efficient and uniform illumination for head-mounted displays.
Implementation Method 1
A respective optical element of the plurality of optical elements is configured to redirect light having a first polarization and transmit light having a second polarization orthogonal to the first polarization
Implementation Method 2
A respective switchable cell of the one or more switchable cells includes optically anisotropic molecules (e.g., liquid crystals). The optically anisotropic molecules are configurable to control a polarization of transmitted light
Implementation Method 3
A respective switchable cell of the one or more switchable cells includes optically anisotropic molecules (e.g., liquid crystals)
Data Source
AI summary
An optical device includes a substrate, a plurality of optical elements positioned on the substrate, and one or more switchable cells. A respective optical element of the plurality of optical elements is configured to redirect light having a first polarization and transmit light having a second polarization orthogonal to the first polarization. The plurality of optical elements includes a first optical element located on a first region of the substrate and a second optical element located on a second region of the substrate. A respective switchable cell of the one or more switchable cells includes optically anisotropic molecules. The one or more switchable cells include a first switchable cell located on a first cell location of the substrate between the first region and the second region of the substrate. Also disclosed are a display device including the optical device and a method performed by the optical device.