Single Display 3D HMD Using Diffractive Optical Elements
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Solution Overview
Problem
Existing head-mounted display (HMD) technologies require multiple display devices to achieve 3D imaging, leading to complex configurations and increased size, while single-display solutions fail to produce 3D images due to identical images being viewed by both eyes.
Innovation Solution
A single display device utilizes light with different wavelengths for each eye, employing a system of diffractive optical elements to separate and direct red, green, and blue light to each eye based on wavelength differences, allowing for 3D image formation without the need for multiple displays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two display devices are used to guide different images to left and right eyes for 3D display, then 3D image can be displayed, but device complexity and overall size increase
Solution Approach 1:
The patent merges the functions of two separate display devices into a single display device by using wavelength-division multiplexing. The display device emits multiple wavelengths of light (first and second wavelengths) that are separated by optical systems to guide different images to the left and right eyes respectively, achieving 3D display functionality with a single device.
Solution Approach 2:
The patent changes the wavelength parameter of light to differentiate between left eye and right eye images. By emitting light at different wavelengths (first wavelength for left eye, second wavelength for right eye) from a single display device, the system can separate and guide different images to each eye, enabling 3D display without requiring multiple display devices.
2Reliability
If two display devices are used to guide different images to left and right eyes for 3D display, then 3D image can be displayed, but overall size increases
Solution Approach 1:
The patent combines the functionality of two display devices into one by utilizing wavelength-division multiplexing. A single display device emits multiple wavelengths that are subsequently separated by optical systems to provide different images to the left and right eyes, reducing the overall volume of the HMD while maintaining 3D display capability.
Solution Approach 2:
The patent uses wavelength as a distinguishing parameter to separate left and right eye images from a single display device. By modulating light at different wavelengths and using optical systems to separate these wavelengths, the patent achieves 3D display functionality in a more compact form factor.
3Device complexity
If a single display device is used to display images for both eyes, then device size and complexity are reduced, but 3D image cannot be displayed since same image is viewed by both eyes
Solution Approach 1:
The patent changes the wavelength parameter of light emitted by the single display device to enable 3D display. By emitting first light at a first wavelength for the left eye and second light at a second wavelength for the right eye, the system can provide different images to each eye while maintaining configuration simplicity.
Solution Approach 2:
The patent applies local quality by directing different wavelengths of light to different eyes through separate optical paths. The optical system separates the first wavelength light to the left eye and the second wavelength light to the right eye, enabling each eye to receive a distinct image for 3D visualization.
4Device complexity
If multiple wavelengths of light are used for left and right eyes from a single display device, then 3D image can be displayed with simplified configuration, but light separation and direction control becomes challenging
Solution Approach 1:
The patent uses wavelength as a distinguishing parameter to separate light paths. The optical system is designed to separate first light at a first wavelength from second light at a second wavelength, directing them to different eyes. This parameter-based separation simplifies the overall configuration while providing a clear mechanism for light differentiation.
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 enables the display of 3D images using a single device, reducing size and complexity while improving image quality by leveraging the higher human visibility in green light to minimize loss and enhance image quality.
Implementation Method 1
a first diffractive optical element that is provided on a second surface of a light guide unit through which the parallel light emitted from the optical system is transmitted, reflects the first light having been transmitted through the light guide unit at an angle of +θ1 with respect to a reference direction, and transmits the second light having been transmitted through the light guide unit
Data Source
AI summary
In an optical system, first green light reflected by a first diffractive optical element propagates in a left direction by repeating total reflection within a first light guide unit, is reflected by a third diffractive optical element, and is guided to a left eye. First red light reflected by a fifth diffractive optical element propagates in a left direction by repeating total reflection within a second light guide unit, is reflected by a seventh diffractive optical element, and is guided to a left eye. First blue light reflected by a ninth diffractive optical element is reflected by an eleventh diffractive optical element, and is guided to a left eye.