Wavelength-Selective Hologram Optical Element for AR Imaging
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Solution Overview
Problem
Conventional AR devices suffer from reduced imaging quality due to the reflection of ambient light rays by concave mirrors, which affects the stereoscopic floating images.
Innovation Solution
An AR device utilizing a laser source, spatial light modulator, and hologram optical element, where the hologram optical element provides a concave mirror effect only for the coherent laser wavelength, diffracting and magnifying the hologram to form a stereoscopic virtual image while ignoring stray ambient light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a general concave mirror is used to magnify the stereoscopic image, then the magnification function is achieved, but ambient light rays are also reflected causing reduced imaging quality
Solution Approach 1:
The hologram optical element is designed with wavelength-selective properties, providing concave mirror effect only for the specific wavelength of the coherent laser ray while being transparent to other wavelengths. This local quality differentiation allows the element to selectively reflect useful laser light while ignoring harmful ambient light, thereby improving imaging quality without suffering from ambient light interference
Solution Approach 2:
The patent changes the optical parameters of the hologram optical element to be responsive only to a specific wavelength range. By tuning the hologram's diffraction characteristics to match the coherent laser wavelength, the element achieves wavelength-selective reflection, effectively filtering out ambient light of different wavelengths while maintaining the desired magnification function
2Reliability
If a conventional AR display device is designed, then stereoscopic image display is achieved, but the device occupies significant physical space and requires additional components
Solution Approach 1:
The patent merges the magnification function and the wavelength-selective filtering function into a single hologram optical element. This integration eliminates the need for separate concave mirrors and wavelength filters, thereby reducing the overall device volume while maintaining reliable stereoscopic image display
Solution Approach 2:
The hologram optical element serves multiple functions simultaneously: it acts as a magnifying lens, a wavelength selector, and a beam director. This multi-functionality reduces the number of required components and minimizes the device footprint while ensuring reliable stereoscopic image formation
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 enhances imaging quality by preventing ambient light interference and allows for a smaller spatial light modulator size, reducing device dimensions while maintaining effective stereoscopic image formation.
Implementation Method 1
The spatial light modulator provides a diffraction pattern, wherein when the spatial light modulator receives the coherent laser ray, the diffraction pattern diffracts the coherent laser ray as a hologram
Implementation Method 2
The hologram optical element provides a concave mirror effect merely in response to a wavelength of the coherent laser ray, wherein the hologram optical element receives the hologram and magnifies the hologram to provide a stereoscopic virtual image
Implementation Method 3
The laser source provides a coherent laser ray
Data Source
AI summary
The disclosure provides an augmented reality (AR) device, a notebook, and smart glasses. The AR device includes a laser source, a spatial light modulator (SLM), and a hologram optical element (HOE). The laser source provides a coherent laser ray. The SLM provides a diffraction pattern solely corresponding to the coherent laser ray. When the SLM receives the coherent laser ray, the diffraction pattern diffracts the coherent laser ray as a hologram in response to the coherent laser ray. The HOE provides a concave mirror effect merely in response to a wavelength of the coherent laser ray, wherein the HOE receives the hologram and magnifies the hologram as a stereoscopic virtual image.