Optical Distance Detector with Segmented Photosensitive Surfaces
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Solution Overview
Problem
Optical distance-measuring devices face challenges in maintaining a constant reception signal across a wide measuring range, particularly at close ranges due to parallax issues that result in a decreasing measurement signal and limited accessible range.
Innovation Solution
The device employs a reception unit with multiple, separately activated photosensitive surfaces, allowing only the necessary surfaces to be used for measurement, reducing noise from extraneous light and increasing measurement accuracy by tapering or expanding the active detector surfaces to ensure adequate signal detection across varying distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the reception channel is located a distance away from the transmission channel to avoid optical crosstalk, then optical crosstalk suppression is improved, but detection problems arise at close ranges due to parallax causing the measurement signal to approach zero
Solution Approach 1:
The detector is divided into multiple separately addressable photosensitive surfaces or regions, allowing selective activation of only those regions needed for the current measurement range, thereby maintaining signal strength at close ranges while keeping the reception channel separated from the transmission channel
Solution Approach 2:
The device dynamically switches between different photosensitive surfaces based on the measurement range. For close-range measurements, photosensitive surfaces positioned to receive displaced beams are activated, while for distant measurements, surfaces aligned with the optical axis are used, thereby adapting to parallax effects without requiring the reception channel to be close to the transmission channel
2Adaptability or versatility
If the measuring range is extended to cover both close and distant ranges, then the accessible measuring range is improved, but the reception signal becomes inconsistent across the range
Solution Approach 1:
The device dynamically switches between different photosensitive surfaces based on the measurement range. For close-range measurements, photosensitive surfaces positioned to receive displaced beams are activated, while for distant measurements, surfaces aligned with the optical axis are used, thereby maintaining consistent reception signals across the entire measuring range
Solution Approach 2:
The device changes the active photosensitive surface parameter based on the measurement range. By selecting appropriate surfaces for close and distant ranges, the system maintains optimal signal reception consistency across the full measuring range from a few centimeters to several hundred meters
3Measurement precision
If all photosensitive surfaces are activated to detect returning light, then the measurement signal is improved, but noise from extraneous light increases
Solution Approach 1:
The device extracts and activates only the specific photosensitive surfaces needed for the current measurement, leaving other surfaces inactive. This selective activation removes the harmful effect of extraneous light detection while maintaining adequate measurement signal detection
Solution Approach 2:
Different photosensitive surfaces are positioned to receive light from different angular ranges. By activating only the locally appropriate surface for the current measurement range, the system maintains high measurement precision while avoiding noise from extraneous light that would be detected by other surfaces
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 enhances the signal-to-noise ratio and expands the measurable range by ensuring a strong, consistent measurement signal across both close and distant ranges, improving resolution and frequency response.
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
The active, photosensitive surface of the detector of the reception unit described in DE 10 130 763 A1 tapers in the direction of a beam displacement
Data Source
AI summary
A device for optically measuring distance, in particular a hand-held device, comprising an transmission unit (12) which is provided with a light source (17, 18) for emitting optical measuring radiation (13, 20, 22) towards a target object (15), and a capturing unit (14) which is arranged at a distance from the optical axis (38) of the transmission unit (12). The capturing unit (14) comprises at least one optical detector (54) for capturing optical radiation (16, 49, 50) reflected by the target object (15). The detector (54) of the capturing unit (14) comprises a plurality of light-sensitive surfaces (70, 72, 74; 170, 172, 174; 270, 272, 274; 370, 372; 470, 472; 570, 572) which are separated from each other and which are be activated separately. The invention also relates to a method for operating a device for optically measuring distance.