Six-Element Imaging Lens for Compact System Length
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Solution Overview
Problem
Conventional imaging lenses for portable electronic devices face challenges in reducing system length while maintaining satisfactory optical performance, with existing designs either being too long or suffering from significant distortion aberration.
Innovation Solution
The design of an imaging lens comprising six specific lens elements with carefully optimized refractive powers and surface shapes, including concave and convex portions, arranged to minimize system length while ensuring good optical performance, including low spherical and chromatic aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the system length of the imaging lens is reduced to meet miniaturization requirements, then the imaging lens can be used in slim electronic devices, but the optical performance deteriorates with significant distortion aberration
Solution Approach 1:
The patent applies parameter changes by optimizing the refractive indices, dispersion values, and curvature radii of all six lens elements. Specifically, the first lens element has refractive index 1.505-1.565 and dispersion 56.5-60.0, the second lens element has refractive index 1.645-1.720 and dispersion 25.0-32.0, and similar optimized parameters for other elements. These parameter optimizations enable the lens to achieve distortion aberration of 20% or less while maintaining a compact system length of 0.5 cm or less.
Solution Approach 2:
The patent uses composite material principles by combining lens elements made of different materials with varying refractive indices and dispersion characteristics. The six lens elements are made from different optical materials (resin or glass) with specifically selected properties to complement each other, allowing the compact lens system to correct various aberrations including distortion, spherical aberration, and chromatic aberration simultaneously.
2Manufacturing precision
If six lens elements are used to maintain optical performance, then satisfactory imaging quality is achieved, but the system length increases making it unsuitable for slim devices
Solution Approach 1:
The patent applies spheroidality by using aspherical surfaces on multiple lens elements. Specifically, the object-side surface of the first lens element, the image-side surface of the second lens element, the object-side surface of the third lens element, and other surfaces are designed as aspherical surfaces with specific curvature profiles. This allows better control of light rays and aberration correction in a more compact configuration compared to traditional spherical surfaces.
Solution Approach 2:
The patent applies dimensionality change by transitioning from traditional spherical lens surfaces to aspherical surfaces, adding a dimensional aspect to the surface geometry. The aspherical surfaces introduce radial curvature variations that enable more efficient space utilization and aberration control, achieving compact system length while maintaining optical performance.
3Length of moving object
If the thickness of individual lens elements is reduced to shorten system length, then miniaturization is achieved, but aberration control becomes more difficult
Solution Approach 1:
The patent applies local quality by giving different thickness characteristics to different lens elements and different regions of the same element. For example, the first lens element has specific thickness constraints, the second lens element has concave portions at peripheral areas with specific depth requirements, and the fifth lens element has a thickness at the optical axis that satisfies specific relationships. This localized optimization enables aberration control while maintaining compact overall dimensions.
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 imaging lens achieves a reduced system length of less than 5.7 mm while maintaining excellent optical performance, with aberrations controlled within acceptable ranges, enabling high-quality imaging in compact electronic devices.
Implementation Method 1
Each of the first lens element, the second lens element, the third lens element, the fourth lens element, the fifth lens element and the sixth lens element has an object-side surface facing toward the object side, and an image-side surface facing toward the image side. The first lens element has a refractive power.
Data Source
AI summary
An imaging lens includes an aperture stop, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, and a sixth lens element arranged in order along an optical axis. The imaging lens satisfies ALT/T5≦6.90, where T5 is a thickness of the fifth lens element, and ALT is a summation of thicknesses of the six lens elements. Through designs of surfaces of the lens elements and relevant lens parameters, a short system length of the imaging lens may be achieved while maintaining good optical performance.