Freeform Lens Optical System for Thin High-Resolution Camera Modules
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Solution Overview
Problem
Existing camera modules face challenges in achieving high optical performance with multiple lenses due to difficulties in deriving excellent optical properties and aberration characteristics, while also facing issues with increased size and thickness, which complicates integration into compact devices.
Innovation Solution
An optical system comprising lenses with asymmetrical and symmetrical freeform surfaces, along with specific refractive powers and focal lengths, is designed to improve optical performance and reduce overall size by optimizing lens alignment and shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a plurality of lenses is included to improve optical performance, then optical properties and aberration characteristics are improved, but the overall length and size of the module increase
Solution Approach 1:
The patent applies asymmetry by introducing freeform surfaces with asymmetrical shapes in the seventh and eighth lenses. These asymmetrical surfaces allow for optimized light path control without requiring additional lens elements, thereby maintaining compact overall length while achieving improved optical properties and aberration characteristics.
Solution Approach 2:
The patent utilizes parameter changes by implementing freeform surfaces with variable curvature radii and asymmetrical shapes. By changing the surface parameters from traditional spherical or rotational symmetric forms to freeform configurations, the optical system achieves better aberration correction with fewer lens elements, preventing increase in overall module size.
2Manufacturing precision
If the size of the image sensor is increased to realize high-resolution, then high-definition imaging is achieved, but the TTL of the optical system increases, thereby increasing the thickness
Solution Approach 1:
The freeform surfaces with asymmetrical shapes in the seventh and eighth lenses enable optimized light path control that reduces the TTL (Total Track Length) of the optical system. This allows the use of larger image sensors for high-resolution imaging without proportionally increasing the thickness of the camera module.
Solution Approach 2:
The patent introduces freeform surfaces that add dimensional complexity to the lens surfaces. By utilizing freeform geometry with asymmetrical characteristics in multiple dimensions, the optical system achieves better control over light paths and reduces TTL, enabling thinner camera modules with larger image sensors for high-definition imaging.
3Manufacturing precision
If a plurality of lenses is included to improve optical performance, then aberration characteristics are improved, but the device complexity increases
Solution Approach 1:
The patent reduces device complexity by replacing traditional spherical or rotational symmetric lens surfaces with freeform surfaces that have asymmetrical shapes. This single design change enables better aberration correction without requiring additional lens elements, thereby maintaining simpler overall device structure while achieving improved optical performance.
Solution Approach 2:
The patent simplifies the optical system by changing surface parameters from conventional spherical forms to freeform configurations. This parameter transformation allows a single lens element to perform what would traditionally require multiple lenses, reducing the total number of components and simplifying the overall device complexity while maintaining excellent aberration characteristics.
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, reduced thickness, and enhanced optical performance at the center and periphery of the field of view, allowing for a slim and compact camera module design.
Implementation Method 1
at least one of the object-side and sensor-side surfaces 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
Implementation Method 2
at least one of an object-side and sensor-side surfaces of the seventh lens has at least one critical point
Data Source
AI summary
The optical system disclosed in the embodiment of the invention includes first to eighth lenses aligned along an optical axis from an object side toward a sensor side, wherein an object-side surface of the first lens is convex, at least one of an object-side and sensor-side surfaces of the seventh lens has at least one critical point, and at least one of the object-side and sensor-side surfaces 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 both lens surfaces having a symmetrical shape in the first direction with respect to the optical axis, and both lens surfaces having a symmetrical shape in the first direction in the second direction with respect to the optical axis.