Five-Lens Camera Optical System Aperture Placement and Aberration Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing camera lenses with five small lenses face challenges in achieving ultra-thin and long back focal length designs, leading to issues with aperture placement, coma aberration, and chromatic aberration, particularly when the F value is below 2.4, which affects on-axis resolution and meets high-pixel requirements.
Innovation Solution
A camera lens design comprising five lenses with specific refractive powers and aspherical surfaces, where the aperture is placed between the second and third lenses, and conditions are set to optimize focal lengths, curvatures, and Abbe numbers to improve resolution and correct aberrations, ensuring a long back focal length and wide angle of view while maintaining a bright F value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the aperture is arranged between the first lens and the second lens to achieve ultra-thin design and long back focal length, then the back focal length is extended and lens thickness is reduced, but the gap between the first lens and second lens becomes narrower making it difficult to ensure space for the aperture
Solution Approach 1:
The patent moves the aperture from the traditional position between the first and second lenses to the space between the second and third lenses. This dimensional repositioning in the optical path allows sufficient space for aperture placement while maintaining the ultra-thin design and long back focal length requirements. The aperture is positioned where there is adequate radial and axial space without compromising the compact lens structure.
2Illumination intensity
If the F value is set to a bright value below 2.4 to improve light gathering capability, then the brightness is increased, but the coma aberration becomes larger causing resolution near on-axis to decrease
Solution Approach 1:
The patent applies aspherical surfaces to specific lens surfaces (object side of first lens, image side of second lens, object side of fourth lens) to locally correct coma aberration in the bright F value design. This localized application of aspherical geometry targets the regions where coma aberration is most pronounced, allowing the lens to maintain both bright F value (below 2.4) and high resolution near the on-axis region.
Solution Approach 2:
The patent carefully controls the curvature parameters and refractive indices of the lens elements to balance brightness and resolution. By optimizing the curvature radii and thickness of each lens element, the design achieves an F value below 2.4 while maintaining adequate resolution through precise parameter control of the optical system.
3Manufacturing precision
If the third lens has an Abbe number above 0 to reduce chromatic dispersion, then the chromatic aberration is reduced, but it is still difficult to eliminate chromatic aberration on-axis when the F value is set to a bright value below 2.4
Solution Approach 1:
The patent uses a combination of lens materials with different Abbe numbers to correct chromatic aberration in the bright F value design. The first, second, and third lenses use materials with specific Abbe numbers (Vd1, Vd2, Vd3) that work together to eliminate chromatic aberration on-axis. This composite material approach allows the system to achieve both bright F value (below 2.4) and effective chromatic aberration correction that meets high-pixel requirements.
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 design achieves improved resolution and reduced aberrations, particularly coma and chromatic aberrations, across the image field, enhancing on-axis and off-axis performance and supporting high-pixel requirements.
Implementation Method 1
a first lens with negative refractive power, a second lens with positive refractive power, a third lens with negative refractive power, a fourth lens with positive refractive power, and a fifth lens with negative refractive power
Data Source
AI summary
The present invention provides a camera lens including: a first lens having a negative refractive power with a convex object side surface, a second lens having a positive refractive power with a convex object side surface, a third lens having negative refractive power with a concave image side surface, a fourth lens having a positive refractive power with a concave object side surface, and a fifth lens having a negative refractive power with a convex object side surface and a concave image side surface. The object side surface of the first lens, an object side surface and the image side surface of the third lens, the object side surface and an image side surface of the fourth lens, the object side surface and the image side surface of the fifth lens are aspherical surfaces. Specific conditions are satisfied.