Two-Lens Compact Imaging Assembly Reducing Total Track Length
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Solution Overview
Problem
Conventional compact imaging lens assemblies for mobile phone cameras face challenges in maintaining high resolution while keeping the lens size compact, as they often require complex manufacturing processes and are prone to high sensitivity and aberrations due to the use of multiple lens elements.
Innovation Solution
A compact imaging lens assembly comprising two lens elements with specific refractive powers and aspheric surfaces, along with an aperture stop between them, which reduces the total track length and sensitivity, and corrects chromatic and astigmatism aberrations, allowing for improved image quality and manufacturing simplicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If three lens elements are used to compensate aberrations, then image quality is improved, but total track length increases and manufacturing complexity increases
Solution Approach 1:
The patent extracts the essential aberration compensation function from the conventional three-lens Triplet structure and implements it using only two lens elements. By removing one lens element while retaining the core aberration correction capability through optimized surface curvatures and aspheric designs, the patent achieves simplified structure with maintained image quality.
Solution Approach 2:
The patent changes the optical parameters by using aspheric surfaces with specific curvature radii ratios and refractive power distributions. The first lens element has positive refractive power with specific curvature relationships (|R1|<|R2|), and the second lens element has negative refractive power with controlled curvature ratios (0.5<|R3/R4|<2.0), enabling effective aberration compensation with fewer elements.
2Length of moving object
If lens thickness is decreased to make the lens more compact, then total track length is reduced, but material distribution becomes uneven and manufacturing yield decreases
Solution Approach 1:
The patent optimizes the thickness parameters of the two lens elements within specific ranges relative to the focal length (0.3<CT1/f<0.8 and 0.2<CT2/f<0.6) to maintain adequate material distribution while achieving compact dimensions. The aspheric surface designs also help distribute stress and material more evenly throughout the lens elements.
3Length of moving object
If bi-convex first lens element is used, then compact size is achieved, but refractive power increases and system sensitivity increases making yield control difficult
Solution Approach 1:
The patent applies aspheric surface designs with specific local curvature characteristics to the first lens element. The object-side surface has curvature radius R1 and the image-side surface has curvature radius R2, with the ratio |R1/R2| controlled within 0.3<|R1/R2|<0.7. This local optimization of surface geometry allows compact size while controlling overall refractive power and system sensitivity.
4Device complexity
If two lens elements are used instead of three, then total track length is shortened and manufacturing yield is improved, but aberration compensation capability is reduced
Solution Approach 1:
The patent uses composite optical designs combining spherical and aspheric surface elements. The first lens element features an aspheric object-side surface and spherical image-side surface, while the second lens element has spherical object-side and aspheric image-side surfaces. This composite approach enables effective aberration compensation with only two elements by leveraging the complementary strengths of different surface geometries.
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 track length, lowers the sensitivity of the lens assembly, and enhances image quality by correcting aberrations, making it suitable for high-resolution mobile phone cameras with a simpler manufacturing process.
Implementation Method 1
a first lens element with positive refractive power having a convex object-side surface and a concave image-side surface, at least one of the object-side and the 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, at least one of the object-side and the image-side surfaces thereof being aspheric
Data Source
AI summary
This invention provides a compact imaging lens assembly, in order from an object side to an image side, including a first lens element with positive refractive power having a convex object-side surface and a concave image-side surface with at least one of the two surfaces thereof being aspheric, a second lens element with negative refractive power having a concave object-side surface and a convex image-side surface with at least one of the two surfaces thereof being aspheric, and an aperture stop disposed between the first and second lens elements. There are only two lens elements with refractive power in the compact imaging lens assembly. By such an arrangement, total track length and optical sensitivity of the compact imaging lens assembly can be reduced while a high image quality can also be obtained.