Six-Lens Optical Imaging With Freeform Surfaces for Rectangular Sensors
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Solution Overview
Problem
The differences in shape and size between lenses and image sensors in optical imaging systems hinder improvements in optical performance.
Innovation Solution
An optical imaging system is designed with a specific arrangement of lenses, including first to sixth lenses, where the refractive powers and surface shapes are tailored to address these differences, utilizing non-rotationally symmetrical lenses with freeform surfaces to adjust aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a circular lens is used for mass production, then manufacturing ease is improved, but optical performance deteriorates due to shape differences with rectangular image sensors
Solution Approach 1:
The patent applies asymmetry by introducing a lens with non-rotationally symmetric freeform surfaces (aspherical or more complex shapes) to compensate for the rectangular image sensor geometry. This asymmetric lens design allows the optical system to achieve optimal performance with rectangular sensors while maintaining compatibility with circular lens manufacturing processes.
Solution Approach 2:
The patent applies local quality by designing different lens elements with specific surface shapes tailored to their individual functions. The fourth lens has a specific aspherical shape, while the fifth and sixth lenses have freeform surfaces with particular curvatures, optimizing each region's contribution to aberration correction while maintaining overall system performance.
2Area of stationary object
If the image sensor is made larger than the lens, then coverage is improved, but aberration correction deteriorates
Solution Approach 1:
The patent applies segmentation by dividing the optical system into multiple lens elements (first through sixth lenses) with different refractive powers and surface shapes. This segmentation allows each lens to address specific aberration issues, collectively achieving optimal performance across the entire rectangular image sensor area.
Solution Approach 2:
The patent applies parameter changes by carefully controlling the refractive powers, surface curvatures, and spacing of multiple lens elements. The fourth lens has negative refractive power with specific aspherical parameters, while the fifth and sixth lenses have freeform surfaces with optimized curvatures, collectively correcting aberrations across the extended image sensor area.
3Device complexity
If a simple lens arrangement is used, then device complexity is reduced, but optical performance deteriorates
Solution Approach 1:
The patent applies dynamics by designing lens surfaces with varying curvatures and shapes (aspherical and freeform) that can dynamically adjust light paths to correct different types of aberrations. The fourth lens uses aspherical surfaces while the fifth and sixth lenses use freeform surfaces, providing dynamic control over optical performance.
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 system enhances optical performance by improving aberration correction and field of view, specifically achieving half field of views between 20 to 68 degrees, suitable for camera modules in mobile terminal devices.
Implementation Method 1
The first lens has refractive power having a sign different from a sign of refractive power of the second lens
Data Source
AI summary
An optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens disposed in order from an object side. The first lens has refractive power having a sign different from a sign of refractive power of the second lens. One of an image-side surface of the fifth lens and an object-side surface of the sixth lens is convex, and the other is concave. One of the fourth to sixth lenses has both surfaces having a freeform surface shape.