Imaging Lens Aspheric Eighth Lens Aberration Correction
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Solution Overview
Problem
Conventional imaging lenses for small cameras face challenges in downsizing while maintaining proper aberration correction, leading to increased size and complexity.
Innovation Solution
The imaging lens configuration includes a specific arrangement of lenses with positive and negative refractive powers, including an eighth lens with an aspheric image-side surface having at least one inflection point, which allows for effective chromatic and axial chromatic aberration correction, reducing the lens profile and thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the number of lenses is increased to correct aberrations, then aberration correction is improved, but the total track length increases and the lens becomes larger
Solution Approach 1:
The patent applies parameter changes by using an aspheric surface with inflection points on the eighth lens. This changes the geometric parameters of the lens surface from a simple spherical shape to a complex aspheric profile, enabling better aberration correction within a compact total track length while maintaining the eight-lens configuration
Solution Approach 2:
The patent employs spheroidality by introducing an aspheric surface with inflection points on the image-side surface of the eighth lens. This curved surface design allows for more effective control of light rays and better aberration correction compared to traditional spherical surfaces, achieving improved performance without increasing the overall lens length
2Length of stationary object
If the profile of the imaging lens is reduced for downsizing, then the lens size is decreased, but aberration correction becomes insufficient
Solution Approach 1:
The patent uses parameter changes by implementing an aspheric surface with inflection points on the eighth lens. This advanced surface geometry allows the lens to maintain compact dimensions while achieving superior aberration correction that would otherwise require a longer optical path
Solution Approach 2:
The patent applies local quality by concentrating optical correction functionality in the eighth lens through the aspheric surface with inflection points. This localized enhancement allows the overall lens profile to be reduced while maintaining proper aberration correction through the specialized design of this specific lens element
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 imaging lens with high resolution and proper aberration correction, suitable for small cameras, achieving both downsizing and improved optical performance.
Implementation Method 1
a eighth lens with the negative refractive power having a concave image-side surface
Implementation Method 2
chromatic aberration and axial chromatic aberration can be properly corrected
Implementation Method 3
the image-side surface of the eighth lens is formed as the aspheric surface having at least one inflection point
Implementation Method 4
it is also possible to control an incident angle of a light ray emitted from the imaging lens to the image plane of the image sensor within the range of chief ray angle (CRA)
Implementation Method 5
field curvature and distortion at an image periphery can be properly corrected
Data Source
AI summary
There is provided a compact imaging lens configured to properly correct aberrations. The imaging lens includes, in order from an object side to an image side, a first lens L1 with positive refractive power, a second lens L2 with negative refractive power, a third lens L3 with positive refractive power, a fourth lens L4 with positive refractive power, a fifth lens L5, a sixth lens L6, a seventh lens L7 with positive refractive power, and an eighth lens L8 with negative refractive power. The eighth lens L8 is formed in a shape of a meniscus lens in a paraxial region, and has an aspheric image-side surface having at least one inflection point. In addition, the following conditional expressions are satisfied:−5.00<f2/f<−2.0010.00<f4/f<25.00wheref: a focal length of the overall optical system of the imaging lens,f2: a focal length of the second lens, andf4: a focal length of the fourth lens.