Eyepiece Optical Structure with Binary and Fresnel Patterns
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Solution Overview
Problem
Existing head-mounted display devices face challenges in achieving a large field-of-view angle, high image resolution, low distortion, small field curvature, and a small volume simultaneously, which affects visual comfort and image quality.
Innovation Solution
The eyepiece optical structure incorporates a lens group with an optical binary surface pattern and a Fresnel surface pattern, optimized to satisfy specific relational expressions for focal lengths and radius values, reducing system aberration and improving optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional optical systems are used to achieve large field-of-view angle, then visual experience quality improves, but system volume and complexity increase
Solution Approach 1:
The optical system is divided into multiple lens groups (T1, T2, etc.) with specific functions. The first lens group T1 contains the binary surface pattern and Fresnel surface pattern, while subsequent groups handle different optical corrections. This segmentation allows each group to be optimized independently for specific functions, achieving large field-of-view without proportionally increasing overall system volume.
Solution Approach 2:
The patent introduces binary surface patterns and Fresnel surface patterns that operate in additional optical dimensions. These patterns create multiple focal points and light paths simultaneously, effectively expanding the field-of-view in a way that doesn't linearly increase physical system dimensions, thus achieving large FOV with compact volume.
2Measurement precision
If optical components are optimized for high image resolution, then image quality improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent changes the surface parameter descriptions from traditional continuous aspheric surfaces to discrete binary surface patterns and Fresnel zone patterns. These patterns use step-wise height changes rather than continuous curvature variations, which can be manufactured with standard precision techniques while achieving high optical performance. The binary patterns use two discrete surface levels, and Fresnel patterns use concentric rings with specific height steps, both of which are more manufacturable than high-precision continuous aspheres.
3Ease of operation
If distortion is reduced through aberration optimization, then visual comfort improves, but system complexity increases
Solution Approach 1:
The patent introduces specific intermediary lens groups (T2, T3) between the object plane and image plane that serve as mediators for aberration correction. These intermediate groups contain elements with specific focal lengths and positions designed to correct distortions and field curvatures without requiring complete redesign of the entire optical system, thus improving visual comfort with moderate complexity increase.
4Stability of the object's composition
If field curvature is minimized, then image uniformity improves, but optical design difficulty increases
Solution Approach 1:
The patent applies different surface pattern types to different regions and groups of the optical system. The binary surface patterns and Fresnel patterns are applied specifically to the first lens group T1 where they most effectively control field curvature. Subsequent lens groups use traditional aspheric and spherical surfaces optimized for their local functions. This localized application of different surface qualities achieves image uniformity across the entire field without requiring all elements to be equally complex.
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 configuration enables a large field angle, low distortion, and high image quality with reduced sensitivity of optical components, facilitating easier processing and assembly, and providing a uniform and high-definition visual experience.
Implementation Method 1
an optical binary surface pattern and a Fresnel surface pattern distributed in a direction from a human eye viewing side to a display device side are arranged on the lens group T1
Data Source
AI summary
The present invention relates to an eyepiece optical structure, an eyepiece system and an optical device. The structure includes a lens group T1 on which an optical binary surface pattern and a Fresnel surface pattern distributed in a direction from a human eye viewing side to a display device side are arranged. The lens group T1 has a focal length of F, and a clear aperture of D, and F and D satisfy the following relational expression: 1.9≤F/D. The optical binary surface pattern has a focal length of F2, and F and F2 satisfy the following relational expression: −120<F2/F<10.78. In the present invention, a combination of the novel optical surface pattern and the Fresnel surface pattern is adopted, and the focal length of each lens and lens group achieves great elimination of system aberration under the condition of meeting specific conditions.