Optical Distance Detector Surface Shape for Signal Intensity
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Solution Overview
Problem
Biaxial optical distance-measuring devices face challenges in maintaining a constant reception signal across varying measurement ranges, particularly at close ranges, due to parallax issues that cause the measurement signal to wander and become defocused, leading to reduced signal intensity.
Innovation Solution
The device incorporates a reception unit with a photosensitive detector surface that expands laterally and elongates in the direction of beam displacement as the target object distance decreases, ensuring a sufficient signal intensity is maintained by increasing the effective detector surface area and compensating for defocusing effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a biaxial measurement system is used to avoid complex beam-splitting systems and suppress optical crosstalk, then device complexity is reduced and optical crosstalk is suppressed, but measurement signal intensity decreases at close ranges due to parallax
Solution Approach 1:
The detector surface is designed with non-uniform sensitivity distribution, where different regions have different sensitivity characteristics. The sensitivity is highest at the center and decreases toward the edges, which compensates for the varying signal intensities caused by parallax at different measurement distances. This local quality variation allows the detector to maintain consistent measurement capability across the entire measurement range without requiring complex beam-splitting systems.
2Object-affected harmful factors
If the optical detector is positioned at a distance from the optical axis to enable biaxial measurement, then optical crosstalk is suppressed, but the measurement signal wanders laterally and becomes defocused at close ranges
Solution Approach 1:
The solution moves from one-dimensional lateral positioning to two-dimensional surface area utilization. Instead of trying to keep the measurement signal focused on a single point or line, the invention utilizes the entire detector surface area, with each region contributing to the measurement based on its sensitivity weight. This dimensional transition allows the system to accept defocused signals across the surface while maintaining measurement precision through weighted evaluation.
3Adaptability or versatility
If the measurement range is extended to include close ranges, then the device becomes more versatile, but the beam diameter increases and signal intensity per surface area decreases
Solution Approach 1:
The invention changes the parameter of detector sensitivity distribution from uniform to non-uniform. By varying the sensitivity parameter across different regions of the detector surface, the system compensates for the inverse relationship between measurement distance and signal intensity. Close-range measurements utilize regions with higher sensitivity weighting, while far-range measurements utilize regions with lower sensitivity weighting, maintaining consistent measurement quality across the extended measurement range.
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 allows for a consistent and strong reception signal across a wide measurement range without affecting the optical path, thereby expanding the device's operational range and maintaining a good signal-to-noise ratio.
Implementation Method 1
A portion of the returning light that has been reflected or scattered by the target object is detected by the device
Implementation Method 2
A portion of the returning light that has been reflected or scattered by the target object is detected by the device
Implementation Method 3
the receiving unit that includes an optical detector located in this measuring device—which serves to receive the optical radiation returning from the target object
Data Source
AI summary
The invention relates to a device for optically measuring distance, in particular a hand-held device, comprising an transmitter unit (12) which is provided with a light source (17, 18) for transmitting optical measuring radiation (13, 20, 22) to a target object (15), and a capturing unit (14) which is arranged at a distance on the optical axis (38) of the transmitter unit (14). Said capturing unit (14) comprises at least one optical detector (54) comprising a detection surface (66) for capturing optical radiation (16, 49, 50) reflected by the target object (15). According to the invention, the detection surface (66) of the detector (54) comprises an optical near range element (68), whose optically active surface (72, 74) is elongated in the direction (61) of the radiation shift for receding target object separations (48) and expands or has at least one essentially constant extension.