Four-Element Optical Lens System Aberration Correction
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Solution Overview
Problem
Conventional optical systems with a four-element lens structure face challenges in achieving a balance between a large field of view, compact size, and high image quality due to limitations in material properties and assembly techniques, particularly in maintaining relative illumination and image quality with a short axial distance between the third and fourth lens elements.
Innovation Solution
An optical imaging lens system comprising four lens elements with specific refractive powers and surface curvatures, including a first lens element with positive refractive power, a second lens element with negative refractive power, a third lens element with positive refractive power, and a fourth lens element with negative refractive power, where the fourth lens element has an object-side surface convex and an image-side surface concave in paraxial regions, and at least one convex critical point in the off-axial region, optimizing axial distances and curvature ratios to improve image quality and field of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the axial distance between the third and fourth lens elements is reduced to achieve compact size, then the overall system size is reduced, but the relative illumination and image quality deteriorate
Solution Approach 1:
The fourth lens element employs different surface curvatures in different regions: the object-side surface has a convex critical point in the off-axial region while maintaining convexity in the paraxial region, and the image-side surface has a concave critical point in the off-axial region while maintaining concavity in the paraxial region. This local variation in surface quality allows the lens to maintain image quality even with reduced axial distance between elements.
Solution Approach 2:
The patent applies aspheric surfaces to the fourth lens element with specific curvature parameters (convex critical point on object-side surface, concave critical point on image-side surface) to change the optical path and improve light distribution. This parameter optimization enables compact design while maintaining relative illumination and image quality.
2Area of stationary object
If the field of view is enlarged to meet imaging requirements, then the coverage area is increased, but the optical system becomes more complex and harder to manufacture
Solution Approach 1:
The fourth lens element uses aspheric surfaces with optimized curvature parameters (convex critical point on object-side surface, concave critical point on image-side surface) to control off-axial light rays. This parameter optimization enables the system to achieve large field of view while maintaining manufacturing feasibility through standardized aspheric surface fabrication.
3Device complexity
If the number of lens elements is reduced to simplify the structure, then the device complexity is reduced, but the image quality and aberration correction deteriorate
Solution Approach 1:
The fourth lens element incorporates localized aspheric surface features (convex critical point on object-side surface, concave critical point on image-side surface) that provide enhanced aberration correction capabilities. This localized quality enhancement allows a single lens element to perform functions that would traditionally require multiple elements, reducing overall system complexity while maintaining image quality.
Solution Approach 2:
The fourth lens element with aspheric surfaces serves multiple functions: it corrects spherical aberration, controls off-axial light rays, maintains relative illumination, and enables large field of view. This multi-functionality within a single element reduces the total number of lens elements needed in the system.
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 described optical imaging lens system effectively balances field of view, compact size, and image quality, reducing aberrations and enhancing illumination, while allowing for flexible design and manufacturing flexibility using glass or plastic materials, thus addressing the limitations of conventional systems.
Implementation Method 1
a first lens element (110), wherein the first lens element (110) has positive refractive power
Implementation Method 2
a second lens element (120), wherein the second lens element (120) has negative refractive power
Implementation Method 3
a third lens element (130), wherein the third lens element (130) has positive refractive power
Implementation Method 4
a fourth lens element (140), wherein the fourth lens element (140) has negative refractive power
Data Source
AI summary
An optical imaging lens system includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element and a fourth lens element. The first lens element with positive refractive power has an object-side surface being convex in a paraxial region thereof. The second lens element has negative refractive power. The third lens element with positive refractive power has an object-side surface being convex in a paraxial region thereof. The fourth lens element with negative refractive power has an object-side surface being convex in a paraxial region thereof and an image-side surface being concave in a paraxial region thereof, the image-side surface of the fourth lens element has at least one convex critical point in an off-axial region thereof, and the two surfaces thereof are both aspheric. The optical imaging lens system has a total of four lens elements.