Five-Element Imaging Lens Assembly for Compact Wide Field of View
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Solution Overview
Problem
Conventional imaging lens assemblies struggle to achieve both high image quality and compactness, particularly in compact electronic devices that require a wide field of view, as they either compromise on light entry for larger view angles or extend the lens configuration to accommodate wide fields of view, failing to meet market demands for both features simultaneously.
Innovation Solution
An imaging lens assembly comprising five lens elements with specific refractive powers and surface curvatures, including positive and negative refractive powers, aspheric surfaces, and critical points, optimized to converge light from large view angles while minimizing the total track length and back focal length, thereby enhancing image quality and compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional lens configurations are used to achieve wide field of view, then the field of view is improved, but the total track length increases and compactness deteriorates
Solution Approach 1:
The patent employs aspheric surfaces on multiple lens elements (first, third, fourth, and fifth lens elements) to replace traditional spherical surfaces. This curvature optimization enables more efficient light path control, allowing wide field of view (90 degrees or more) to be achieved while maintaining a compact total track length of 2.0mm or less, directly resolving the contradiction between field of view and compactness
Solution Approach 2:
The patent implements specific parameter relationships including focal length ratios (0.25 < f1/f3 < 1.00, -0.50 < f4/f5 < 0.00) and curvature radius relationships (0.50 < R1/R2 < 2.00, -2.00 < R3/R4 < -0.50) to optimize the optical path. These parameter optimizations enable the lens assembly to achieve wide field of view while maintaining compact dimensions, effectively balancing field of view and total track length
2Length of moving object
If compact lens configurations are used to reduce total track length, then compactness is improved, but light entry for larger view angles is compromised and field of view deteriorates
Solution Approach 1:
The aspheric surfaces on the first, third, fourth, and fifth lens elements enable efficient light path control within a compact form factor. The specific aspheric coefficients and surface curvatures allow light from large view angles (90 degrees or more) to be properly directed to the image sensor, achieving both compactness (total track length ≤ 2.0mm) and wide field of view simultaneously
Solution Approach 2:
The patent applies different surface characteristics to different lens elements: the first lens element has a convex object-side surface and concave image-side surface, the third lens element has concave object-side and convex image-side surfaces, the fourth lens element has convex object-side and concave image-side surfaces, and the fifth lens element has convex object-side and concave image-side surfaces. This localized optimization of surface quality enables compact configuration while maintaining wide field of view capability
3Manufacturing precision
If lens elements are added to correct aberrations and improve image quality, then image quality is improved, but device complexity and total track length increase
Solution Approach 1:
The aspheric surfaces on four out of five lens elements provide superior aberration correction compared to spherical surfaces. This allows the patent to achieve high image quality (distortion less than 5.0%, astigmatism less than 3.0 micrometers) with only five lens elements, reducing overall device complexity while maintaining excellent image quality
Solution Approach 2:
The patent optimizes specific parameter relationships including focal length ratios (0.25 < f1/f3 < 1.00, -0.50 < f4/f5 < 0.00), curvature radius ratios (0.50 < R1/R2 < 2.00, -2.00 < R3/R4 < -0.50), and Abbe number combinations (1.50 < V1/V3 < 3.00, -3.00 < V2/V4 < -1.00). These parameter optimizations enable effective aberration correction with a compact five-element configuration, achieving high image quality without excessive device complexity
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 corrects aberrations and reduces the total track length, achieving a compact and high-quality imaging lens assembly that satisfies the demands for both wide field of view and compactness, as demonstrated by the specified conditions and embodiments.
Implementation Method 1
The first lens element has positive refractive power, the second lens element has positive refractive power, the fourth lens element with negative refractive power, and the fifth lens element has positive refractive power
Data Source
AI summary
An imaging lens assembly includes five lens elements, which are, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element and a fifth lens element. The first lens element has positive refractive power. The second lens element has positive refractive power. The fourth lens element with negative refractive power has an object-side surface being convex in a paraxial region thereof and an image-side surface being concave in a paraxial region thereof, wherein the two surfaces of the fourth lens element are both aspheric. The fifth lens element having an image-side surface being concave in a paraxial region thereof, wherein two surfaces of the fifth lens element are both aspheric, and the image-side surface of the fifth lens element includes at least one convex critical point in an off-axis region thereof.