Distance Measuring Device with Electronic Light Amount Control
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Solution Overview
Problem
Conventional distance measuring devices face challenges in performing high-speed optical path switching and light amount adjustment, making it difficult to measure distances accurately and efficiently, especially when measuring multiple moving objects or performing 3-dimensional measurements.
Innovation Solution
The device incorporates a light projecting unit, a reference reflection unit that is relatively movable and integrally provides an optical filter with gradually changing density, and a control arithmetic unit that generates internal reference standards to match varying photodetection light amounts, allowing for high-speed distance measurement without mechanical optical path switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If mechanical optical path switching is used to alternate between distance measuring light and internal reference light, then the photodetection light amount can be adjusted, but the switching speed is limited and high-speed distance measurement cannot be achieved
Solution Approach 1:
The patent replaces the mechanical optical path switcher with an electronic control system. The light emitting element is controlled to emit distance measuring light and internal reference light at different time periods through electronic timing control, eliminating mechanical moving parts and enabling high-speed operation.
Solution Approach 2:
The patent uses periodic emission of distance measuring light and internal reference light in alternating time periods. This periodic action allows the photodetection element to receive alternating signals from both light sources, enabling the system to function without mechanical switching while maintaining the ability to compare phases.
2Speed
If an amplitude filter with continuously changing density is used to adjust light amount, then photodetection light amount can be equalized, but the adjustment speed is limited and cannot keep up with moving objects
Solution Approach 1:
The patent replaces the mechanical amplitude filter with an electronic control approach. The light emitting element's emission intensity and timing are controlled electronically to produce distance measuring light and internal reference light with matched photodetection light amounts, eliminating mechanical adjustment limitations.
Solution Approach 2:
The patent changes the emission parameters (intensity, timing, duration) of the light emitting element to control the photodetection light amount. By adjusting these parameters electronically, the system can rapidly adapt to different measurement conditions without mechanical filter adjustment.
3Measurement precision
If the internal reference light optical path length is made equal to the distance measuring light optical path length, then measurement accuracy improves, but the device becomes more complex and larger
Solution Approach 1:
The patent extracts the reference reflection unit from the main optical path and positions it separately. The internal reference light is generated by reflecting distance measuring light off this separate unit, simplifying the overall optical path configuration while maintaining the ability to perform accurate phase comparison.
Solution Approach 2:
The patent introduces a reference reflection unit as an intermediary element. This unit reflects the distance measuring light to create the internal reference light, serving as a mediator that simplifies the optical path while enabling accurate distance measurement through phase comparison.
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 solution enables high-speed distance measurement by adjusting light amounts electronically, eliminating the need for mechanical switching and ensuring accurate calculations, even when measuring multiple moving objects or during 3-dimensional scans.
Implementation Method 1
A light emitting element 1 such as a laser diode emits a laser beam, and intensity of the laser beam is modulated at a predetermined frequency
Implementation Method 2
A reflected distance measuring light 3′ reflected by the object 6 to be measured is received by a photodetection element 7 such as a photo-diode
Data Source
AI summary
The present invention provides a distance measuring device, which comprises a light projecting unit for projecting a distance measuring light (22) to an object to be measured, a reference reflection unit (55) provided relatively movable and arranged at a known position so as to traverse the projected distance measuring light, a photodetection unit (7) for receiving a reflection light from the object to be measured as a reflected distance measuring light (22′) and a reflection light from said reference reflection unit as an internal reference light (22″), and a control arithmetic unit (15) for calculating a distance to the object to be measured based on a photodetection signal relating to the reflected distance measuring light and based on a photodetection signal relating to the internal reference light.