Image Pickup Lens Aberration Control via Alternating Power Elements
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Solution Overview
Problem
Current image pickup lenses face challenges in achieving a small volume, light weight, high resolution, and large Field of View while effectively managing optical aberrations and sensitivity.
Innovation Solution
The design comprises a sequence of lenses with specific refractive powers and surface configurations, including a negative and positive refractive power sequence, an aperture for a large Field of View, and an aspherical fifth lens made of plastic with optimized focal lengths and dispersion coefficients to reduce aberrations and sensitivity, along with a filter to eliminate non-visible light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the number of lenses is increased to reduce aberrations and improve resolution, then the optical performance is improved, but the total length and volume of the lens system increases
Solution Approach 1:
The optical system is divided into five distinct lens elements with alternating positive and negative refractive powers. Each lens element is optimized for specific aberration correction, allowing the system to achieve high optical performance while maintaining a compact total length of 1.0 to 1.5 times the focal length.
Solution Approach 2:
The patent employs specific parameter ranges for each lens element including refractive indices (1.5 < Nd < 2.0), Abbe numbers (20 < Vd < 60), and focal length ratios (0.3 < |f1/f| < 1.0, 0.5 < |f3/f| < 1.0). These optimized parameters enable effective aberration control within a compact form factor.
2Adaptability or versatility
If the Field of View is enlarged to capture more scene, then the versatility is improved, but the optical aberrations and sensitivity increase
Solution Approach 1:
Different lens elements are designed with specific local optical properties to correct aberrations in different field regions. The first, third, and fifth lenses have negative refractive power with specific surface curvatures optimized for off-axis ray control, while the second and fourth lenses with positive refractive power correct axial and lateral chromatic aberrations, enabling large FOV with controlled aberrations.
Solution Approach 2:
The patent achieves a dynamic balance between Field of View and aberration control through optimized focal length ratios. The conditional expressions 0.3 < |f1/f| < 1.0 and 0.5 < |f3/f| < 1.0 allow the system to adaptively manage ray angles across the field, maintaining aberration control while supporting large FOV configurations.
3Volume of stationary object
If the lens elements are made with higher refractive index to reduce element count, then the volume is reduced, but the manufacturing precision and control over aberrations deteriorates
Solution Approach 1:
The patent uses a composite material strategy with five lens elements made from different optical materials with specific refractive indices (1.5 < Nd < 2.0) and Abbe numbers (20 < Vd < 60). This combination of materials with varying optical properties enables effective aberration correction while maintaining a compact overall volume through optimized element distribution and focal length ratios.
4Manufacturing precision
If the aperture is increased to improve light gathering, then the resolution is improved, but the sensitivity to aberrations and the volume increase
Solution Approach 1:
The optical design preliminarily corrects for aberrations that will be introduced by large aperture configurations. The alternating positive and negative lens elements are pre-configured with specific power distributions and surface curvatures that proactively compensate for spherical aberration, coma, and astigmatism, enabling the system to achieve high resolution with large aperture while maintaining compact volume through efficient optical path management.
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 results in an image pickup lens with a balanced performance in reducing aberrations, total length, and sensitivity, achieving a compact size with high resolution and large Field of View, while maintaining control over incoming light energy and aberrations.
Implementation Method 1
an image pickup lens comprises a first lens having a negative refractive power, a second lens having a positive refractive power, a third lens having a negative refractive power, a fourth lens having a positive refractive power, and a fifth lens having a negative refractive power
Implementation Method 2
at least one of a ninth surface and a tenth surface of the fifth lens is an aspherical surface
Data Source
AI summary
An image pickup lens comprises a first lens having negative refractive power, a second lens having positive refractive power, a third lens having negative refractive power, a fourth lens having positive refractive power, and a fifth lens having negative refractive power, from an object side to an image side. The image pickup lens has an optical axis. A portion of a surface of the first lens facing the object side and close to the axis is convex, a portion of a surface of the first lens facing the image side and close to the axis is concave. A portion of a surface of the fourth lens facing the object side and close to the axis is convex, a portion of a surface of the fourth lens facing the image side and close to the axis is convex. The image pickup lens has large field of view and small volume.