Six-Lens Optical Imaging System Compact Design
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Solution Overview
Problem
Conventional optical imaging systems for compact electronic devices, such as digital cameras and mobile phones, face challenges in achieving a compact design with good aberration correction and high image quality while maintaining a short total length, as existing designs often require increased rear focal length to avoid aberrations, limiting the system's ability to reduce the total length effectively.
Innovation Solution
The optical imaging system employs a combination of six lens elements with specific refractive powers and surface shapes, including a plastic sixth lens element with a concave image-side surface and aspheric surfaces, to achieve a telecentric effect, reducing the rear focal length and total length while enhancing image quality. This design includes a stop and an image sensor, with the second lens element having negative refractive power and the sixth lens element having negative refractive power, both with concave surfaces, to correct aberrations and improve light sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional optical imaging systems use more lens elements (four-lens, five-lens, or six-lens designs) to improve image quality and aberration correction, then image quality and aberration correction ability are improved, but the total length of the optical system increases
Solution Approach 1:
The patent applies parameter changes by optimizing the refractive powers and focal lengths of individual lens elements. Specifically, it sets the focal length of the sixth lens element (f6) to satisfy 0.1<f6/|f5|<0.3 and the combined focal length to satisfy 0.3<f5+f6/f<0.6, which allows achieving good aberration correction with a shorter total system length compared to conventional designs
Solution Approach 2:
The patent uses composite material principles by combining lens elements with different refractive powers and materials. The system uses a combination of positive and negative refractive power elements, including plastic lens elements, to achieve both compact size and high image quality through material composition optimization
2Length of stationary object
If the sixth lens element is designed with positive refractive power to increase view angle and reduce total length, then view angle increases and total length decreases, but aberrations occur due to excessive positive refractive power
Solution Approach 1:
The patent applies the counterweight principle by balancing the positive refractive power of the sixth lens element with negative refractive power elements (particularly the second and fifth lens elements). This counterbalancing approach prevents excessive positive refractive power from causing aberrations while maintaining the compact design and increased view angle
Solution Approach 2:
The patent optimizes the refractive power parameters by setting specific constraints on the sixth lens element's focal length (0.1<f6/|f5|<0.3) and its contribution to the total system (0.3<f5+f6/f<0.6), which allows achieving compact size without inducing aberrations
3Object-affected harmful factors
If the rear focal length is increased to avoid aberrations caused by excessive positive refractive power, then aberration correction improves, but the total length of the optical system cannot be reduced
Solution Approach 1:
The patent fundamentally changes the parameter relationship by setting the sixth lens element's focal length to a small positive value (satisfying 0.1<f6/|f5|<0.3) rather than using a large rear focal length. This parameter inversion allows achieving aberration correction through optimized lens combination rather than increasing system length
Solution Approach 2:
The patent inverts the conventional approach by not increasing rear focal length to correct aberrations, but rather using a short-focal-length sixth element with carefully controlled positive refractive power combined with negative power elements to achieve both compact size and aberration correction simultaneously
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 solution effectively reduces the total length of the optical imaging system while maintaining high image quality and aberration correction, allowing for a more compact design with improved light sensitivity and image reception speed, suitable for compact electronic devices.
Implementation Method 1
the first lens element with positive refractive power has a convex object-side surface; the second lens element with negative refractive power; the third lens element with positive refractive power; the fourth lens element with positive refractive power; the fifth lens element with positive refractive power; the plastic sixth lens element with negative refractive power
Data Source
AI summary
An optical imaging system for pickup, sequentially arranged from an object side to an image side, comprising: the first lens element with positive refractive power having a convex object-side surface, the second lens element with refractive power, the third lens element with refractive power, the fourth lens element with refractive power, the fifth element with refractive power; the sixth lens element made of plastic, the sixth lens with refractive power having a concave image-side surface with both being aspheric, and the image-side surface having at least one inflection point.