Compact Beam Expander for VR AR Headset Backlight Efficiency
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Solution Overview
Problem
Current VR/AR headset display devices face design constraints and power usage issues due to low transmission efficiency in multilayered display devices, which affects battery lifetime and image quality.
Innovation Solution
A compact beam expander system using a light source, first and second gratings, and a polarizing component to expand a light beam in two dimensions, providing a more efficient backlight for VR/AR headsets, improving image uniformity and diffraction efficiency while mitigating artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multilayered display devices are used in VR/AR headsets, then display functionality is improved, but transmission efficiency decreases leading to increased power consumption
Solution Approach 1:
The patent changes the optical parameters of the display system by introducing a beam expander with specific grating structures and polarization control. This transforms the light propagation characteristics to achieve better transmission efficiency through the multilayered display device, thereby reducing power consumption while maintaining display functionality.
Solution Approach 2:
The beam expander acts as an intermediary component between the light source and the multilayered display device. It pre-conditiones the light beam through diffraction and polarization control, enabling more efficient light transmission through the display layers and reducing the overall power requirement.
2Illumination intensity
If traditional backlight systems are used, then illumination is provided, but device compactness is compromised and power efficiency is reduced
Solution Approach 1:
The traditional backlight system is segmented and replaced with a compact beam expander consisting of discrete optical components (gratings, polarizers) arranged in a folded optical path. This segmentation allows for miniaturization while maintaining illumination functionality.
Solution Approach 2:
The optical path is folded back on itself using mirrors or prisms, transitioning from a linear arrangement to a three-dimensional folded configuration. This reduces the overall device volume while preserving the necessary optical path length for effective beam expansion and illumination.
3Area of stationary object
If beam expansion is achieved, then illumination area increases, but device complexity increases
Solution Approach 1:
The beam expander design integrates multiple functions into a compact unit: beam expansion, polarization control, and illumination distribution. This multi-functionality reduces the need for separate components, thereby managing device complexity while achieving broad illumination area.
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 solution enhances the compactness and power efficiency of VR/AR headsets by increasing the illumination area, improving image uniformity, and reducing artifacts, leading to better display performance and extended battery life.
Implementation Method 1
The first grating performs a first diffraction to expand the light beam in a first dimension to form a first beam
Implementation Method 2
The second grating performs a second diffraction to expand the first beam in a second dimension to provide a backlight for a display device
Implementation Method 3
The polarizing component changes a polarization state of the first diffracted beam
Data Source
AI summary
An apparatus of the subject technology includes a light source to generate a light beam, a first grating illuminated by the light beam, and a second grating optically coupled to the first grating. The first grating performs a first diffraction to expand the light beam in a first dimension to form a first beam. The second grating performs a second diffraction to expand the first beam in a second dimension to provide a backlight for a display device.