Four-Lens Image Pickup System for Compact High-Resolution Imaging
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Solution Overview
Problem
Existing image pickup lenses for portable devices face challenges in achieving downsizing, thinning, high resolution, small F value, and a wide angle of field simultaneously, while maintaining sufficient brightness and correcting various aberrations.
Innovation Solution
The image pickup lens configuration consists of an aperture stop followed by a biconvex first lens, a meniscus-shaped second lens, a meniscus-shaped third lens, and a biconcave fourth lens, with specific focal length and surface curvature relationships to minimize total track length, ensure back focus, and correct aberrations, using plastic materials for cost-effective production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of lenses is increased to four or more to achieve higher resolution and wider angle of field, then the imaging performance is improved, but the total track length increases and the lens becomes larger and thicker
Solution Approach 1:
The patent applies the nesting principle by arranging multiple lenses (four or more) in a compact configuration where each lens is positioned close to the others, with the second lens having a convex surface facing the first lens and the third lens having a concave surface facing the second lens, creating a nested-like structure that minimizes the overall length while maintaining high imaging performance
Solution Approach 2:
The patent utilizes aspheric surfaces on the lens elements, particularly the second and third lenses, to correct aberrations in a different dimensional approach rather than simply adding more lens elements along the optical axis, thereby achieving high resolution without proportionally increasing the total track length
2Illumination intensity
If the F value is reduced to achieve brighter imaging for high-pixel sensors, then the brightness is improved, but the lens becomes larger and more complex
Solution Approach 1:
The patent changes the optical parameters by using aspheric surfaces on the second and third lenses, which allows for better control of light paths and aberration correction, enabling a smaller F value (higher brightness) without requiring an excessive number of lens elements or increasing overall complexity
3Area of moving object
If the angle of field is widened to capture more scene, then the field of view is improved, but the aberration correction becomes more difficult and the lens design more complex
Solution Approach 1:
The patent applies aspheric surfaces (non-spherical curvature) to the second and third lenses, which enables effective correction of off-axis aberrations such as coma and distortion that become more pronounced with wider angle of field, thereby maintaining manufacturing precision and image quality across the expanded field of view
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 configuration enables a compact, high-performance lens with a wide angle of field, effective aberration correction, and sufficient brightness, suitable for high-pixel imaging elements in portable devices, while facilitating mass production and cost reduction.
Implementation Method 1
a first lens of a biconvex shape having a positive refractive power with convex surfaces facing both the object side and the image plane side near an optical axis; a second lens of a meniscus shape having a negative refractive power with a concave surface facing the object side near the optical axis
Data Source
AI summary
An image pickup lens having a relatively wide angle of field with various aberrations preferably corrected and having a small F-value is achieved. The image pickup lens is composed of, in order from an object side, an aperture stop, a first lens of a biconvex shape having a refractive power, a second lens of a meniscus shape having a negative refractive power with a concave surface facing the object side near the optical axis, a third lens of a meniscus shape having a positive refractive power with a concave surface facing the object side near the optical axis, and a fourth lens of a biconcave shape having a negative refractive power near the optical axis, wherein the image pickup lens satisfies a following conditional expression (1):0.6<f1/f<0.8 (1)where f1 represents a focal length of the first lens, and f represents a focal length of the overall image pickup lens.