Compact Optical Assembly for Wide Field of View Digital Cameras
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Solution Overview
Problem
Conventional point action cameras suffer from significant distortion and astigmatism errors, especially at wide field of view angles, and struggle with stray light suppression and high dynamic range imaging, while existing optical designs are either non-compact or fail to achieve low distortion and astigmatism with high resolution and low chromatic aberration.
Innovation Solution
A compact optical assembly with multiple lens elements, including at least one aspheric lens element, is designed to provide a wide field of view exceeding 120 degrees, featuring a low total track length to effective focal length ratio, minimal distortion, and reduced astigmatism, while incorporating an IR cut filter and a telecentric cone to deliver high modulation transfer function and suppress stray light by strategically managing ghost image formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional optical designs are used for wide field of view cameras, then field of view is increased, but distortion and astigmatism errors increase significantly
Solution Approach 1:
The optical system is divided into multiple lens groups (first lens group with positive power, second lens group with negative power, third lens group with positive power) that work together to correct aberrations. Each group contributes differently to the overall optical performance, allowing wide field of view while maintaining image quality through distributed aberration correction across the groups.
Solution Approach 2:
Specific lens elements within the groups have tailored characteristics (aspheric surfaces, specific refractive indices, particular curvatures) optimized for their local function in correcting specific types of aberrations. For example, certain lenses have aspheric surfaces specifically designed to reduce distortion in particular field regions while maintaining overall system performance.
2Manufacturing precision
If optical correction for distortion and astigmatism is added, then image quality improves, but device complexity increases
Solution Approach 1:
Multiple correction functions are merged into a compact multi-group lens structure where the first, second, and third lens groups collectively provide distortion and astigmatism correction. The aperture stop is strategically positioned between groups to simultaneously control aberrations and enable a compact form factor, merging correction functionality with space-saving design.
Solution Approach 2:
Aspheric surfaces are employed on specific lens elements to provide superior aberration correction compared to spherical surfaces. The aspheric profiles enable more effective control of distortion and astigmatism with fewer elements, reducing overall system complexity while maintaining high correction performance.
3Length of moving object
If compact design is implemented with low TTL/EFL ratio, then camera size is reduced, but achieving wide field of view with low distortion becomes difficult
Solution Approach 1:
The optical design achieves dynamic performance characteristics through its multi-group structure, where the arrangement of positive and negative power groups creates a system that can deliver wide field of view and low distortion despite compact physical dimensions. The alternating power groups enable flexible light path control within limited space.
Solution Approach 2:
The patent achieves compactness by optimizing the three-dimensional arrangement of lens groups and utilizing the aperture stop's strategic positioning between groups. This spatial optimization in multiple dimensions allows the system to pack correction functionality into a compact form while maintaining wide field of view performance and low distortion through efficient use of available optical space.
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 assembly achieves high resolution and low distortion across a wide field of view, suppresses stray light, and maintains low astigmatism, enabling high dynamic range imaging with reduced chromatic aberration, thereby improving image quality and compactness.
Implementation Method 1
A compact optical assembly with multiple lens elements, including at least one aspheric lens element, is designed to provide a wide field of view exceeding 120 degrees
Implementation Method 2
incorporating an IR cut filter and a telecentric cone to deliver high modulation transfer function and suppress stray light
Implementation Method 3
multiple lens elements, including at least one aspheric lens element, is designed to provide a wide field of view exceeding 120 degrees
Implementation Method 4
strategically managing ghost image formation
Data Source
AI summary
An optical assembly for a point action camera or other compact digital camera having a wide field of view, includes multiple lens elements, including at least one lens element that has an aspheric lens surface. The optical assembly is configured to provide a field of view in excess of 120 degrees. The optical assembly includes a ratio of a diameter of a first lens element at the object end of the optical assembly to an image diagonal is less than approximately 3.