Two-Lens Optical Assembly with Aspheric Surfaces for Miniaturization
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Solution Overview
Problem
Conventional compact photographing lens assemblies for camera mobile phones face challenges in maintaining image quality, reducing sensitivity, and miniaturization due to limited space, which complicates the correction of aberrations and increases the sensitivity of the optical system.
Innovation Solution
A photographing optical lens assembly comprising two lens elements with specific refractive powers and aspheric surfaces, along with an aperture stop, is designed to improve image quality, reduce sensitivity, and maintain miniaturization by distributing refractive power effectively and positioning the principal point far from the image plane, using a meniscus lens element with positive refractive power and a correction lens with negative refractive power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a triplet lens design is used to correct aberrations, then image quality is improved, but the total track length increases and miniaturization becomes difficult
Solution Approach 1:
The patent extracts and eliminates one lens element from the conventional triplet design, reducing from three lenses to two. This extraction maintains aberration correction capability while significantly reducing the total track length, enabling miniaturization of the lens assembly for mobile phone applications.
Solution Approach 2:
The patent changes the optical parameters by using aspheric surfaces on both the object-side and image-side of each lens element. This parameter change allows a single lens element to perform multiple functions (aberration correction and focusing), enabling the reduction from three to two lenses while maintaining image quality.
2Volume of moving object
If the volume of the lens assembly is reduced, then miniaturization is achieved, but the thickness of lenses must be reduced resulting in poor material homogeneity
Solution Approach 1:
The patent employs plastic lens materials with specifically selected refractive indices and Abbe numbers. By using composite material properties (plastic materials with optimized optical characteristics), the lens achieves both miniaturization and maintained material homogeneity, avoiding the need for thick glass lenses while ensuring uniform optical properties.
3Volume of moving object
If two plastic lens elements with strong refractive power are used, then compact form is maintained, but the sensitivity of the optical system increases
Solution Approach 1:
The patent carefully selects and balances the refractive power parameters of the two lens elements. The first lens element has positive refractive power and the second has negative refractive power, with specifically controlled focal lengths and curvature radii. This parameter balancing reduces optical sensitivity while maintaining compact size.
Solution Approach 2:
The patent applies aspheric surfaces specifically at certain locations (both object-side and image-side of each lens) to locally correct aberrations. This localized quality enhancement allows the use of weaker overall refractive power while maintaining image quality, thereby reducing optical system sensitivity.
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 arrangement enhances image quality, reduces the total track length, and improves the telecentric feature, leading to better photosensitivity and reduced aberrations, while allowing for the use of plastic or glass lens elements produced through injection molding or glass molding for high-precision lens elements.
Implementation Method 1
a first lens element with positive refractive power having a convex object-side surface and a concave image-side surface, the object-side and image-side surfaces thereof being aspheric; a second lens element with negative refractive power having a concave object-side surface and a convex image-side surface, the object-side and image-side surfaces thereof being aspheric
Data Source
AI summary
The present invention provides a photographing optical lens assembly comprising, in order from the object side to the image side: a first lens element with positive refractive power having a convex object-side surface and a concave image-side surface, the object-side and image-side surfaces thereof being aspheric; a second lens element with negative refractive power having a concave object-side surface and a convex image-side surface, the object-side and image-side surfaces thereof being aspheric; and an aperture stop located in front of the first lens element; wherein an Abbe number of the first lens element is V1, an Abbe number of the second lens element is V2, and they satisfy the relation: |V1−V2|<15; and wherein the number of the lens elements of the photographing optical lens assembly is limited to two. Such an arrangement of optical elements can effectively reduce the volume of the lens assembly and the sensitivity of the optical system and enable the lens assembly to obtain a higher resolution.