Optical System Design for Wide-Angle Imaging Aberration Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Image pickup optical systems face challenges in achieving a wide view angle with good optical performance while maintaining a small size, as large angles of incidence lead to shading and color misregistration, and reducing the number of lenses increases spherical aberration and other aberrations.
Innovation Solution
The optical system consists of a first lens unit with negative and positive refractive powers, a cemented lens unit with specific refractive powers and surface configurations, and an aperture stop positioned to satisfy conditional expressions that ensure telecentricity and correct aberrations, allowing for a wide view angle and high-quality imaging across the screen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the number of lenses in the lens unit is reduced to make the system smaller, then the size of the entire system is reduced, but spherical aberration and asymmetric aberration occur more frequently
Solution Approach 1:
The patent applies parameter changes by carefully controlling the refractive powers of individual lenses and the overall lens unit. Specifically, it sets the refractive power of the lens unit (φ1) within a specific range (-0.5 to -0.1) and controls the refractive power of the first lens (φ11) to be between -0.8 and -0.3, which allows for reduced lens count while maintaining aberration correction
Solution Approach 2:
The patent uses a cemented lens composed of multiple lens materials with different refractive indices and Abbe numbers. The cemented lens combines a positive lens and a negative lens made of different glass materials, creating a composite optical element that corrects both spherical and chromatic aberrations while occupying minimal space
2Volume of moving object
If the aperture stop is positioned closer to the object side to reduce system size, then the system becomes more compact, but spherical aberration and asymmetric aberration increase
Solution Approach 1:
The patent applies local quality by assigning specific optical properties to different regions of the optical system. The lens unit closer to the object side has a negative refractive power with specifically controlled individual lens powers, while the lens unit closer to the image side has a positive refractive power. This localized optimization of optical properties allows compact aperture positioning while controlling aberrations
Solution Approach 2:
The patent changes the positioning parameter of the aperture stop to be closer to the object side (with distance D1 from the object-side lens surface vertex satisfying 0.05 < D1/Dt < 0.30), and compensates for the resulting aberrations by adjusting the refractive power parameters of the lenses, particularly setting the first lens power φ11 within -0.8 to -0.3
3Illumination intensity
If the F number is reduced to increase brightness, then the aperture is enlarged, but spherical aberration occurs more frequently
Solution Approach 1:
The patent controls the F number to be within 2.8 to 6.4 and adjusts the refractive power parameters accordingly. The negative refractive power of the first lens unit (φ1 between -0.5 and -0.1) and the specific power distribution in the lens elements work together to correct spherical aberration while maintaining the desired aperture size for brightness
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 compact optical system with a wide view angle, maintaining good optical performance and reducing aberrations, particularly spherical aberration, while ensuring telecentricity and a large aperture, achieving satisfactory results even during image stabilization.
Implementation Method 1
the cemented lens including a third lens having a positive refractive power and a fourth lens having a negative refractive power, the third lens and the fourth lens being cemented to each other
Implementation Method 2
The first lens unit includes a first lens having a negative refractive power and a second lens having a positive refractive power in that order from the object side to the image side
Data Source
AI summary
An optical system includes a first lens unit, an aperture stop, and a second lens unit having a positive refractive power. The first lens unit includes a first lens having a negative refractive power and a second lens having a positive refractive power. The second lens unit includes a cemented lens, a fifth lens having a negative refractive power and a concave surface facing an object side, and a sixth lens having a positive refractive power and a convex surface facing an image side. In the cemented lens, a third lens having a positive refractive power and a fourth lens having a negative refractive power are cemented. A distance D1 from an object-side lens surface vertex of the first lens to the aperture stop and a distance Dt from the object-side lens surface vertex of the first lens to an image plane are appropriately set.