Internal Cone Mirror for Telecentric Optical Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current optical detection systems for industrial production, particularly line scan cameras, face challenges in providing cost-effective telecentric optics over large fields of view, as traditional telecentric optics become prohibitively expensive and cumbersome for diameters larger than 150 mm, and existing solutions fail to achieve accurate geometric measurements like lengths, parallelism, and shape parameters.
Innovation Solution
The use of internal cone mirrors or sector mirrors based on annular conic sections, in combination with line sensors, creates a telecentric view through a circular arc-shaped scanning curve, allowing for cost-effective telecentric optics with a larger depth of field and the ability to cascade systems without significant space or cost constraints, using a sector of a truncated cone or annular conic section with a reflecting inner surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional telecentric optics are used for large fields of view (diameter > 150 mm), then measurement precision is improved, but device cost and complexity increase prohibitively
Solution Approach 1:
The patent divides the optical system into modular components: a line sensor, a telecentric lens, and a folding mirror system. This segmentation allows the complex telecentric optics to be broken into manageable parts that can be independently optimized and assembled, reducing overall system complexity while maintaining measurement precision for large fields of view
Solution Approach 2:
The patent employs nested optical paths where the folding mirror system is integrated within the telecentric lens assembly. The mirror system is positioned inside the optical path of the telecentric lens, creating a compact nested structure that achieves large field of view without proportionally increasing device complexity
2Length of stationary object
If conventional folding mirror systems are used to extend optical path, then device length is reduced, but telecentric imaging is not achieved
Solution Approach 1:
The patent applies local quality by positioning the folding mirrors at specific locations within the optical path where they can fold the beam without compromising the telecentric property. The mirrors are strategically placed to fold only specific portions of the optical path while maintaining parallel light rays at the image plane, achieving both compact length and telecentric imaging capability
3Measurement precision
If telecentric optics are designed for large scan lengths, then measurement precision is improved, but space requirements and cost increase significantly
Solution Approach 1:
The patent uses folding mirrors to redirect light in additional spatial dimensions, folding the optical path back on itself. This allows the optical system to achieve large effective scan lengths by utilizing three-dimensional space more efficiently, reducing the physical footprint while maintaining the measurement precision required for large scan lengths
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 approach enables the creation of telecentric optics that are inexpensive, scalable, and suitable for various applications, including surface inspections, with improved imaging sharpness and the ability to handle large scan lengths, while maintaining a large depth of field and allowing for hypercentric or endocentric optical systems.
Implementation Method 1
A bundle of light rays which emanates from a point on the rotation axis of the truncated cone and whose bundle plane is orthogonal to the rotation axis is reflected by the inner cone mirror in such a way that the reflected rays form a parallel bundle of rays
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The device serves for the optical detection of test objects with at least one optical emission element, in whose beam path a deflecting mirror designed as an internal cone mirror is arranged. According to the invention, the emission element is designed as a photoelectric line sensor (14) or point light source (46) with front optics (12) and is movable relative to the test objects (20) to be scanned, and the emission element and the internal cone mirror (22) opposite it are arranged such that the plane of the rays (16) emanating centrally from the optical center of the front optics (12) is aligned perpendicular to the axis of rotation (A) of the internal cone mirror (22).