Eight-Element Optical Lens Assembly for Fixed-Focus Depth of Field
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Solution Overview
Problem
Conventional optical lenses fail to meet user expectations for depth-of-field effect, especially with advancements in semiconductor technology leading to smaller pixel sizes, necessitating improved optical lens designs.
Innovation Solution
An optical lens assembly comprising multiple lenses with specific focal lengths and configurations, including aspheric surfaces, arranged along an optical axis to achieve a depth-of-field effect without a stepper motor, allowing for fixed focus and three-dimensional image capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional electronic devices use two optical lenses to obtain images, then the device complexity is reduced, but the depth-of-field effect does not meet user expectations
Solution Approach 1:
The optical system is segmented into eight distinct lens elements with alternating positive and negative focal lengths, where each lens contributes to different aspects of image formation and depth-of-field control. This segmentation allows precise manipulation of light paths to achieve the desired depth-of-field effect while maintaining a compact structure suitable for electronic devices.
Solution Approach 2:
The patent employs specific parameter relationships between lens elements, including focal length ratios (0.3<f1/|f2|<0.6, 0.4<|f4|/f5<0.7), curvature radius relationships ((R7+R8)/(R7-R8)>3), and spacing ratios (0.05<d12/f<0.15) to optimize the depth-of-field effect. These parameter changes enable precise control over image formation characteristics without requiring additional mechanical components.
2Manufacturing precision
If additional elements are added to achieve depth-of-field effect, then the depth-of-field characteristics are improved, but the manufacturing cost increases
Solution Approach 1:
Each lens element in the eight-element system serves multiple functions: correcting optical aberrations, controlling light convergence/divergence, and contributing to the overall depth-of-field effect. The aperture stop also serves dual purposes by controlling light quantity and defining the entrance pupil. This multi-functionality eliminates the need for separate depth-of-field control mechanisms, reducing manufacturing cost while achieving the desired optical characteristics.
Solution Approach 2:
The patent merges the depth-of-field control function with the image formation function by integrating it into the lens element design itself. The alternating positive and negative focal length lenses work together as a unified system, where the spacing and curvature relationships between elements collectively produce both the focused image and the desired depth-of-field effect, eliminating the need for additional separate components.
3Manufacturing precision
If the distance between lenses is increased to improve image clarity, then the image quality is improved, but the overall length of the optical lens assembly increases
Solution Approach 1:
The optical system employs a nested arrangement where lens elements with negative focal lengths are positioned between those with positive focal lengths, creating a compact folded optical path. The specific spacing relationships (d23, d34, d45, d56, d67) allow each lens to be optimally positioned relative to others, achieving high image clarity while minimizing the overall axial length through this nested configuration.
Solution Approach 2:
The patent utilizes the radial dimension through aspheric surfaces on key lens elements (first, second, third, and eighth lenses) to control off-axis light rays more effectively. This dimensional approach allows the system to achieve high image clarity across the entire field of view without requiring increased axial separation between lenses, as the aspheric profiles compensate for aberrations that would otherwise require greater spacing to correct.
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 optical lens assembly provides enhanced depth-of-field characteristics and fixed focus capabilities, reducing manufacturing costs by minimizing additional elements while maintaining high image clarity and three-dimensional image capture.
Implementation Method 1
The first lens has a negative focal length... The third lens has a positive focal length... The fifth lens has a positive focal length... The seventh lens has a positive focal length... The eighth lens has a negative focal length... sequentially arranged from the object side to the imaging side along an optical axis
Data Source
AI summary
An optical lens assembly includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens. The first lens has a convex surface toward an object side of the optical lens assembly and a concave surface toward an imaging side of the optical lens assembly. The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens are sequentially arranged along an optical axis from the object side to the imaging side.