Light Guide Element With Overlapping Diffraction Elements For AR Glasses
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Solution Overview
Problem
In augmented reality glasses, the overlap of emission side diffraction elements for different colors leads to the occurrence of multiple images due to differences in diffraction angles caused by varying wavelengths and diffraction structure periods, resulting in a poor display experience.
Innovation Solution
A light guide element with specific configurations, including a light guide plate and diffraction elements, where the diffraction structures of incidence and emission elements are designed to diffract light in different directions, with overlapping positions and intersecting periodic directions to suppress multiple image formation, using surface relief, volume hologram, or polarization diffraction elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If emission side diffraction elements for different colors are disposed to overlap each other to display a color image, then color image display is achieved, but multiple images occur due to different diffraction angles
Solution Approach 1:
The emission side is divided into multiple diffraction elements (first emission diffraction element and second emission diffraction element) with different diffraction structure periods. Each diffraction element is responsible for diffracting light of specific wavelength ranges in different directions, thereby segmenting the color display function to prevent multiple image formation while maintaining color image capability
Solution Approach 2:
Different regions of the emission side are assigned different diffraction properties. The first emission diffraction element has a diffraction structure period optimized for certain wavelengths, while the second emission diffraction element has a different period for other wavelengths. This local differentiation ensures that each color component is diffracted at the correct angle without creating multiple images
2Quantity of substance
If diffraction elements with different periods are used for different colors, then color separation is achieved, but multiple images are formed due to different diffraction angles
Solution Approach 1:
The patent introduces a new dimension of control by arranging diffraction elements not only with different periods but also with specific spatial relationships. The first and second emission diffraction elements are disposed at specific positions and orientations, adding positional and orientational dimensions to the diffraction control, which prevents multiple image formation while maintaining color separation
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 effectively suppresses the occurrence of multiple images by ensuring that light components are diffracted and emitted at appropriate angles, enhancing the display quality of color images in augmented reality glasses.
Implementation Method 1
the first incidence diffraction element and the second incidence diffraction element diffract incident light in different directions to be incident into the light guide plate
Implementation Method 2
light (projection light) projected from a display is diffracted (refracted) using a diffraction element to be incident into one end portion of a light guide plate. As a result, the light is introduced into the light guide plate at an angle such that the light is totally reflected and propagates in the light guide plate
Implementation Method 3
the first emission diffraction element emits light that is diffracted by the first incidence diffraction element and propagates in the light guide plate from the light guide plate
Data Source
AI summary
Provided are a light guide element and an image display apparatus capable of suppressing the occurrence of multiple images. The light guide element includes a light guide plate and a first incidence diffraction element, a second incidence diffraction element, a first emission diffraction element, and a second emission diffraction element that are provided on the light guide plate, in which the first and second incidence diffraction elements diffract incident light in different directions to be incident into the light guide plate, the first emission diffraction element emits light that is diffracted by the first incidence diffraction element and propagates in the light guide plate, the second emission diffraction element emits light that is diffracted by the second incidence diffraction element and propagates in the light guide plate, a period of a diffraction structure of the first incidence diffraction element and a period of a diffraction structure of the second incidence diffraction element are different from each other, a period of a diffraction structure of the first emission diffraction element and a period of a diffraction structure of the second emission diffraction element are different from each other, the first and second emission diffraction elements are disposed at a position where the first and second emission diffraction elements overlap each other in a plane direction of a main surface of the light guide plate, and a periodic direction of the diffraction structure of the first emission diffraction element and a periodic direction of the diffraction structure of the second emission diffraction element intersect with each other.