Optoelectronic Sensor Folding Mirror Compact Design
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Solution Overview
Problem
Laser scanners face challenges in miniaturization while maintaining or improving measurement quality, as they require increased rotational speed and angular resolution, leading to limited installation space and difficulties in accommodating light paths without compromising optical performance.
Innovation Solution
The use of a folding mirror in the reception beam path allows for longer light paths to be accommodated in a smaller space, enabling a compact design with high spatial resolution and reduced extraneous light entry, which is achieved by directing the received light back onto the light receiver after being beam-formed or focused by the receiving optics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the rotational speed is increased for shorter measurement cycles and higher angular resolution, then measurement productivity and precision are improved, but the available time for light collection is reduced, requiring larger receiving optic area which conflicts with miniaturization
Solution Approach 1:
The patent applies beam folding using mirrors to change the spatial dimension of the light path. By introducing reflective elements that redirect the beam at angles, the system achieves longer effective light collection paths within a compact sensor volume, resolving the contradiction between measurement speed and sensor size.
Solution Approach 2:
The receiving optic system is nested within the compact sensor housing by using beam folding to pack the optical path efficiently. Multiple optical elements are arranged in a space-saving configuration where the folded beam path allows the receiving optic to be positioned within the limited sensor volume while maintaining adequate light collection area.
2Quantity of substance
If the area of the receiving optics is made large to collect enough light in short measurement time, then light collection capability is improved, but the sensor volume increases making miniaturization difficult
Solution Approach 1:
The patent uses beam folding to transition from a linear light path to a multi-dimensional folded path. This allows the receiving optic to effectively have a larger area for light collection while the folded geometry confines the overall optical path within a compact sensor volume, decoupling the area-volume relationship.
Solution Approach 2:
The optical path is segmented into multiple segments by introducing folding mirrors. Instead of a single long light path requiring large sensor volume, the path is divided into shorter segments that can be arranged in a compact configuration, maintaining total light collection area while reducing overall sensor volume.
3Quantity of substance
If a long focal length is used to achieve large receiving optic area, then light collection capability is improved, but accommodating the light paths within the sensor becomes more difficult
Solution Approach 1:
The patent introduces beam folding to add spatial dimensionality to the light path accommodation. By folding the beam at specific angles, the system can accommodate long focal length requirements without requiring proportionally long sensor dimensions, as the folded geometry packs the optical path into a more compact three-dimensional arrangement.
Solution Approach 2:
Folding mirrors act as intermediary elements that mediate between the long focal length requirement and the compact sensor volume constraint. These mirrors redirect the beam to allow the receiving optic to be positioned at an effective long focal length while the overall optical path is contained within the limited sensor volume through strategic beam redirection.
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 design maintains or enhances optical properties, allows for the use of sensitive photodiodes, and provides a cost-effective solution that supports high-resolution imaging and distance measurement within limited installation space, improving signal-to-noise ratio and reducing unnecessary light entry.
Implementation Method 1
a folding mirror positioned downstream of the receiving optics in the receiving beam path. Thus, the receiving light, already beam-shaped or focused by the receiving optics, strikes the folding mirror and is then deflected by the folding mirror to the light receiver
Implementation Method 2
A receiving optic directs the received light onto a light receiver, preferably by focusing or bundling the received light
Data Source
Figure 1
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AI summary
An optoelectronic sensor (10) for detecting objects in a monitoring area (22) is specified, comprising a light transmitter (12) for emitting transmitted light (16), a light receiver (36) for generating a received signal from received light (26) from the monitoring area (22), a receiving optic (28), in particular a receiving lens, for focusing the received light (26c) onto the light receiver (36), a movable deflection unit (18, 20) for periodically deflecting the transmitted light (16) and the received light (26), and a control and evaluation unit (48) for acquiring information about objects in the monitoring area (22) based on the received signal. The sensor (10) further comprises a folding mirror (30) arranged downstream of the receiving optics (28) in the receiving beam path of the received light (26) in order to direct the received light (26b-c) onto the light receiver (36).