Display Device Free-Curved Reflection Diffractive Optics
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing display devices using diffraction elements face a decrease in image resolution due to light with wavelengths deviated from a specific wavelength, leading to increased complexity with the use of intermediate lenses, which can result in chromatic aberration and a higher number of optical system components.
Innovation Solution
A display device configuration that includes a first diffraction element, a first reflection element with a concave reflection surface, and a second diffraction element, where the first reflection element forms an intermediate image between itself and the second diffraction element, eliminating the need for an intermediate lens and allowing wavelength compensation, thus reducing the number of optical system components and minimizing chromatic aberration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an intermediate lens is used to form an intermediate image, then the image light can be properly directed to the second diffraction element, but the number of optical system components increases and chromatic aberration occurs
Solution Approach 1:
The patent removes the intermediate lens from the optical system by utilizing the first diffraction element to directly form the intermediate image in space, eliminating the need for this optical component while maintaining the necessary image formation function
Solution Approach 2:
The patent replaces the intermediate lens (refractive optical element) with a diffraction-based image formation mechanism using the first diffraction element, substituting refractive optics with diffractive optics to achieve the same functional result without the associated chromatic aberration
2Power
If a diffraction element is optimized for a specific wavelength, then diffraction efficiency is maximized, but light with deviated wavelengths causes resolution decrease
Solution Approach 1:
The first diffraction element acts as an intermediary that pre-diffracts and spatially separates different wavelengths before they reach the second diffraction element, allowing the system to handle broadband light while maintaining resolution by compensating for wavelength-dependent diffraction angles
Solution Approach 2:
The patent divides the diffraction function into two separate elements: the first diffraction element handles wavelength-dependent diffraction and intermediate image formation, while the second diffraction element handles the final deflection to the observer's eye, allowing each element to be optimized for its specific function
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 configuration effectively compensates for diffraction angle deviations caused by wavelength variations, maintaining image resolution and reducing the complexity and weight of the optical system, while enhancing mounting stability and comfort by locating the image light projecting device towards the rear.
Implementation Method 1
a first diffraction element on which image light emitted from an image light projecting device is incident
Implementation Method 2
a first reflection element on which the image light emitted from the first diffraction element is incident
Implementation Method 3
a second diffraction element configured to emit the image light emitted from the first reflection element toward an eye of an observer
Data Source
AI summary
In an optical system of a display device, a second reflection element, a first diffraction element, a first reflection element, and a second diffraction element are disposed along a traveling direction of image light emitted from an image light projecting device. A reflection surface of the first reflection element is a concave surface being a free-curved surface and being recessed in a central portion with respect to a peripheral portion, and an intermediate image is formed between the first reflection element and the second diffraction element. A reflection surface of the second reflection element is a concave surface being a free-curved surface and being recessed in a central portion with respect to a peripheral portion, and an intermediate image is formed between the second reflection element and the first diffraction element. Therefore, an intermediate lens for forming an intermediate image is not provided.