Eight-Lens Optical System With Freeform Surfaces for Compact Cameras
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Solution Overview
Problem
Existing camera modules face challenges in achieving high optical performance with multiple lenses, leading to increased size and thickness due to aberration issues and larger image sensors, which in turn increase the overall camera and mobile terminal thickness.
Innovation Solution
An optical system comprising first to eighth lenses with specific refractive powers and surface shapes, including asymmetrical and symmetrical freeform surfaces, to improve optical properties and reduce total track length, allowing for a slim and compact structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a plurality of lenses is included to improve optical performance, then image quality and resolution are improved, but the overall length and thickness of the camera module increase
Solution Approach 1:
The patent employs freeform surfaces on lens elements, particularly on the seventh and eighth lenses, which utilize complex curved geometries to correct optical aberrations. This allows achieving high optical performance with fewer lens elements, thereby reducing the overall length of the camera module while maintaining excellent image quality.
Solution Approach 2:
The patent optimizes specific parameter relationships between lens elements, including the focal lengths, spacing, and refractive powers of individual lenses. By carefully controlling these parameters and their relationships, the system achieves superior optical performance with a compact configuration that minimizes the total track length.
2Manufacturing precision
If the size of the image sensor is increased to realize high-resolution, then image quality is improved, but the total track length and thickness of the camera module increase
Solution Approach 1:
The freeform surfaces on the seventh and eighth lenses enable effective correction of field curvature and other aberrations, allowing the system to maintain high optical performance across the entire field of view with a shorter total track length that accommodates larger image sensors for high-resolution imaging.
Solution Approach 2:
The patent introduces freeform surfaces that add dimensional complexity to the lens profiles, enabling correction of optical aberrations in multiple directions simultaneously. This allows achieving high-resolution performance with a more compact axial length by utilizing lateral surface variations rather than simply increasing the number of lens elements.
3Manufacturing precision
If a plurality of lenses is included to improve optical properties, then aberration correction is improved, but the device complexity and number of components increase
Solution Approach 1:
The patent utilizes freeform surfaces on specific lens elements (seventh and eighth lenses) that provide powerful aberration correction capabilities. These complex curved surfaces can correct multiple types of optical aberrations simultaneously, reducing the need for additional lens elements and simplifying the overall optical system configuration.
Solution Approach 2:
The freeform surfaces introduce asymmetrical geometries that are specifically designed to correct off-axis aberrations and field curvature. This asymmetric design allows effective aberration correction with fewer lens elements compared to traditional symmetrical multi-element designs.
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 system achieves improved aberration characteristics and resolving power, maintaining good optical performance at the center and periphery of the field of view while reducing the total track length, resulting in a slim and compact camera module.
Implementation Method 1
first to eighth lenses disposed along an optical axis from an object side to a sensor side, wherein the first lens has positive (+) or negative (−) refractive power on the optical axis
Data Source
AI summary
The optical system disclosed in the embodiment of the invention includes first to eighth lenses disposed along an optical axis from an object side to a sensor side, wherein the first lens has positive (+) or negative (−) refractive power on the optical axis, the second lens has positive (+) refractive power on the optical axis, the third lens has negative (−) refractive power on the optical axis, the seventh lens has positive (+) refractive power on the optical axis, the eighth lens has negative (−) refractive power on the optical axis, at least one of an object-side surface and a sensor-side surface of the seventh lens has at least one critical point, each of an object-side surface and a sensor-side surface of the eighth lens has a critical point, at least one of the object-side surface and the sensor-side surface of the eighth lens has a freeform surface shape in which a lens surface orthogonal to the optical axis in a first direction and a lens surface orthogonal to the optical axis in a second direction are asymmetrical, and the freeform surface may have symmetrical lens surfaces on both sides of the first direction with respect to the optical axis and symmetrical lens surfaces on both sides of the second direction with respect to the optical axis.