Diffractive Optical Element for Compact Wide-Angle Imaging
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Solution Overview
Problem
In the development of compact wide-angle imaging optical systems, the reduction in size leads to increased incident angles on the image sensor, causing false colors and chromatic aberrations, which are difficult to correct using conventional methods.
Innovation Solution
The proposed imaging optical system incorporates an optical element with a diffractive surface having controlled wavelength dispersion characteristics, which reduces the incident angle on the image sensor while satisfying specific inequalities to manage chromatic aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the imaging optical system is reduced in size to achieve compact wide-angle imaging, then the system becomes more compact and portable, but the incident angle on the image sensor increases causing false colors and chromatic aberrations that are difficult to correct
Solution Approach 1:
The patent applies parameter changes by introducing a diffractive optical element with specifically controlled dispersion characteristics. The diffractive surface is designed with a dispersion value that compensates for the chromatic aberrations generated by the compact wide-angle lens system. By adjusting the diffractive optical parameters (such as the diffraction grating period and depth), the system achieves correction of false colors and chromatic aberrations while maintaining the compact form factor.
Solution Approach 2:
The patent employs a composite optical system combining refractive lens elements with a diffractive optical element. This composite structure integrates two different optical mechanisms: the refractive lenses provide the primary focusing and wide-angle field of view, while the diffractive surface provides dispersion control to correct chromatic aberrations. The combination of these two optical principles in a single integrated system allows simultaneous achievement of compact size and chromatic aberration correction.
2Object-affected harmful factors
If conventional methods are used to correct chromatic aberrations in compact wide-angle systems, then correction may be achieved, but the system size cannot be sufficiently reduced and the complexity of correction increases
Solution Approach 1:
The patent extracts the chromatic aberration correction function from the main lens system by introducing a separate diffractive optical element. Instead of attempting to correct chromatic aberrations through complex multi-element lens designs, the invention separates the focusing function (performed by the lens) from the dispersion control function (performed by the diffractive element). This extraction allows for a simpler, more compact overall system while achieving effective chromatic aberration correction.
3Object-affected harmful factors
If the incident angle on the image sensor is reduced to eliminate false colors, then image quality improves, but the optical system becomes more complex and larger
Solution Approach 1:
The patent merges the diffractive optical element with the existing lens structure, integrating it as part of the final lens group or image sensor assembly. This merging approach allows the diffractive surface to work in conjunction with the lens elements without requiring separate correction optics, thereby improving image quality while minimizing increases in system complexity and size.
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 effectively suppresses the incident angle on the image sensor, thereby reducing false colors and ensuring satisfactory correction of chromatic aberrations, resulting in improved image quality.
Implementation Method 1
At least one surface of the optical element is a diffractive surface with a controlled wavelength dispersion characteristic
Implementation Method 2
At least one surface of the optical element is a metasurface with a controlled wavelength dispersion characteristic
Data Source
AI summary
An imaging optical system includes an imaging lens, and an optical element disposed on an image side of the imaging lens. At least one surface of the optical element is a diffractive surface with a controlled wavelength dispersion characteristic. Predetermined inequalities are satisfied.