Eyepiece With Contact Multi-Layer Diffractive Optics
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Solution Overview
Problem
Conventional optical systems using refraction struggle with aberration correction across various wavelengths, leading to increased complexity and weight, while diffractive optics are limited to single wavelengths due to flare issues.
Innovation Solution
A compact optical system employing a contact multi-layer diffractive optics configuration with a first and second lens, where the diffractive optics are formed on one lens surface facing the object, using materials with different refractive indices and dispersions, and optimized for achromatic conditions across a wide wavelength range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional refraction-based optical elements are used to improve image formation performance and reduce aberrations, then optical performance is improved, but the number, size and weight of optical elements increase
Solution Approach 1:
The patent combines refractive optical elements with a diffractive optical element into a single integrated optical system. The diffractive grating is formed on one of the optical surfaces of the lenses, merging two different optical mechanisms (refraction and diffraction) into one compact structure, thereby achieving aberration correction without increasing the number of separate optical elements
Solution Approach 2:
The patent employs a composite optical system that utilizes both refractive materials (lenses) and diffractive structures (grating patterns) with different optical properties. The diffractive element is formed with specific refractive index characteristics that complement the refractive lenses, creating a composite system that corrects chromatic aberrations across multiple wavelengths
2Device complexity
If diffractive optics are used to reduce the number of optical elements, then device complexity is reduced, but optical characteristics in wavelength areas other than the central wavelength deteriorate
Solution Approach 1:
The patent optimizes the diffractive grating parameters (such as grating period, depth, and shape) to achieve broad spectral performance. By carefully selecting the diffractive structure parameters and the refractive index of the diffractive element, the system achieves good optical characteristics across a wide wavelength range, not just at the central wavelength
Solution Approach 2:
The patent applies different optical properties to different parts of the optical system. The diffractive element is strategically positioned on specific optical surfaces of the lenses, and the grating pattern is designed with varying local characteristics to correct chromatic aberrations at different wavelengths and field positions
3Ease of manufacture
If a single diffractive optical surface is used, then manufacturing is simplified, but flare occurs in wavelength areas deviating from the designed wavelength
Solution Approach 1:
The patent uses a composite diffractive structure with multiple layers or zones having different refractive indices and grating characteristics. This composite diffractive element is integrated with refractive lenses to create an achromatic diffractive optical system that reduces flare across a broad wavelength range while maintaining manufacturing feasibility
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 system achieves good optical characteristics across all wavelengths, reducing aberrations and flare, enabling a compact, lightweight, and high-performance optical system suitable for camera lenses and projection systems.
Implementation Method 1
an optical system used for compact, light and high performance observation optical systems and projection optical systems... an eye piece (optical system) where a plano convex shaped first lens and a plano convex shaped second lens are disposed, in a state of respective convex surfaces facing each other, and a diffractive grating surface is formed on one of the optical surfaces
Implementation Method 2
Optical elements using refraction (mainly made of glass) have frequently been used for general optical systems, in order to improve optical performance, particularly image formation performance with decreasing amount of aberrations
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
An eye piece (EL1) is formed having a first lens (L1) having a positive refractive power and a second lens (L2) having a positive refractive power, which are disposed in order from an object (O), and a contact multi-layer diffractive optical element (DOE), which has a first optical element (51) formed with a relief pattern and a second optical element (52) which is in contact with the surface of the first optical element (51) where the relief pattern is formed, is disposed on an optical surface of the first lens (L1) or the second lens (L2).