Hat-Shaped Lens for Laser Scanner Distance Measurement
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Solution Overview
Problem
Existing laser scanners face limitations in measuring range due to large intensity differences in reception light beams, leading to overdriving or inability to distinguish signals at varying distances, which restricts accurate distance determination.
Innovation Solution
A device with a hat-shaped second lens element is introduced between the first lens element and pinhole diaphragm, allowing for differential refraction of light beams based on distance, enabling reception light beams from shorter distances to pass through and optimizing the measuring range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the light receiver processes intense-power reception signals from short distances, then the measuring range is extended toward short distances, but the light detector is overdriven which can lead to destruction or unreliable distance determination
Solution Approach 1:
The pinhole diaphragm creates a spatial filter that selectively transmits light from different angular directions. The light-impermeable element positioned in the focal plane blocks specific angular regions of the light ring, creating position-dependent transmission characteristics that adapt the reception optical unit's response to different object distances
Solution Approach 2:
The reception optical unit with pinhole diaphragm and light-impermeable element acts as an intermediary between the reception light beam and light detector. This optical intermediary selectively attenuates or blocks light paths based on their angular origin, preventing overdriving from short distances while maintaining sensitivity for large distances
2Length of moving object
If the light receiver processes weak-power reception signals from large distances, then the measuring range is extended toward large distances, but the reception signal can no longer be distinguished from ambient and detector noise
Solution Approach 1:
The pinhole diaphragm creates a spatial filter that selectively transmits light from different angular directions. The light-impermeable element positioned in the focal plane blocks specific angular regions of the light ring, creating position-dependent transmission characteristics that adapt the reception optical unit's response to different object distances
Solution Approach 2:
The light-emitting element that causes central shading is converted into a useful component. The shading creates a defined geometric relationship between the light source, pinhole diaphragm, and light-impermeable element, enabling the optical system to use the emitter's position to define the blocking geometry for distance-dependent signal attenuation
3Device complexity
If the light emitter is situated coaxially in front of the reception optical unit to simplify the device structure, then the device complexity is reduced, but the reception light beam reaches the reception optical unit only as a light ring with central region cut out
Solution Approach 1:
The light-emitting element that causes central shading is converted into a useful component. The shading creates a defined geometric relationship between the light source, pinhole diaphragm, and light-impermeable element, enabling the optical system to use the emitter's position to define the blocking geometry for distance-dependent signal attenuation
Solution Approach 2:
The pinhole diaphragm creates a spatial filter that selectively transmits light from different angular directions. The light-impermeable element positioned in the focal plane blocks specific angular regions of the light ring, creating position-dependent transmission characteristics that adapt the reception optical unit's response to different object distances
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 device achieves high accuracy over an extended measuring range by ensuring reception light beams from both short and large distances can be detected, avoiding signal overload and noise interference, thus enhancing the device's operational range and reliability.
Implementation Method 1
the second lens element is an optical element which has in cross section a relatively thick central region, a relatively thin peripheral region and a transition region connecting the thicker central region and the thinner peripheral region... light beams incident on the lens element in the transition region are refracted differently than light beams incident on the central region of the lens element
Data Source
AI summary
A device for determining a distance from an object may include a light emitter for emitting an emission light beam, a light receiver for receiving a reception light beam, and an evaluation unit for determining the distance on the basis of a propagation time of the emission and reception light beams. The reception light beam may arise as a result of reflection of the emission light beam at the object. The light receiver may have a reception optical unit comprising a first lens element and a pinhole diaphragm. A light-impermeable element may shade a central region of the reception optical unit in such a way that the reception light beam is incident in the form of a light ring on the pinhole diaphragm. A second lens element, which is substantially hat-shaped in cross section, is arranged between the first lens element and the pinhole diaphragm.