Electro-optical Distance Meter Using Beam Splitter for Simultaneous Measurement
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Solution Overview
Problem
Conventional electro-optical distance meters require time for distance measurement due to the need to alternately switch light between optical paths, and are affected by temperature phase drift from electrical components, leading to measurement errors.
Innovation Solution
The use of multiple light-emitting elements emitting light modulated with main and adjacent frequencies, split into distance measuring and reference optical paths, with frequency converters generating intermediate frequency signals that allow simultaneous measurement without switching modulation frequencies, enabling faster measurements and reducing temperature phase drift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a shutter is used to alternately switch light between distance measuring optical path and reference optical path, then distance measurement can be performed with error correction, but measurement time increases and motion is slowed at low temperature
Solution Approach 1:
The patent replaces the mechanical shutter system with an optical beam splitter arrangement. Instead of mechanically switching light paths, the beam splitter simultaneously directs light to both the distance measuring optical path and reference optical path, eliminating mechanical movement and associated time delays while maintaining the ability to perform differential measurements for error correction
Solution Approach 2:
The patent merges the distance measuring optical path and reference optical path into a single simultaneous measurement system. By using the beam splitter to divide the light from a single light-emitting element into both paths at the same time, the system performs both measurements concurrently rather than alternately, reducing total measurement time
2Measurement precision
If a shutter is used to switch between optical paths, then distance measurement with error correction is possible, but the system becomes more complex and shutter motion slows at low temperature
Solution Approach 1:
The patent eliminates the mechanical shutter component entirely by using a stationary beam splitter to achieve optical path separation. This substitution removes the moving parts that complicate the system and cause performance degradation at low temperatures, while maintaining the differential measurement capability for error correction
Solution Approach 2:
The patent extracts and removes the shutter mechanism from the optical path switching function. By taking out the unnecessary mechanical component and replacing it with a purely optical beam splitting arrangement, the system achieves the same measurement functionality with reduced complexity and improved temperature performance
3Measurement precision
If light-emitting elements are kept on continuously to reduce temperature phase drift, then measurement accuracy is maintained, but energy consumption increases
Solution Approach 1:
The patent enables continuous optical path separation and simultaneous measurement using the beam splitter, allowing the system to perform measurements quickly enough that the light-emitting elements can be pulsed rather than continuously operated. This maintains temperature stability through rapid sequential measurements while reducing overall energy consumption
Solution Approach 2:
The patent implements periodic pulsing of the light-emitting elements rather than continuous operation. By using the beam splitter to enable rapid alternating measurements between distance and reference paths, the system can synchronize light emission with measurement cycles, reducing energy consumption while maintaining measurement accuracy through frequent sampling
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 allows for quicker distance measurements, reduces the need for shutters, and enables power saving by allowing light-emitting elements to be turned on and off during measurements, while improving measurement accuracy by canceling out temperature phase drift.
Implementation Method 1
a beam splitter 3P, one of these is as a distance measuring light 32P made incident onto a light receiving element 5P through a distance measuring optical path
Implementation Method 2
a light receiving element 5P through a distance measuring optical path for traveling to and from a target reflection object 60P
Implementation Method 3
a frequency converter 7P via an amplifier 9P, and the light receiving element 5P is connected to a frequency converter 8P
Data Source
AI summary
[Problem] To provide an electro-optical distance meter in which the measurement time is reduced, and a temperature phase drift of electrical components is reduced.[Solution Means] An electro-optical distance meter includes a first light-emitting element (13) which emits light modulated with a plurality of main modulation frequencies (F1 and F2), a second light-emitting element (14) which emits light modulated with a plurality of adjacent modulation frequencies (F1−Δf1 and F2−Δf2) close to the main modulation frequencies, respectively, first and second light receiving elements (40 and 48) which receive light emitted from both light-emitting elements, a first frequency converter group (42, 44) connected to the first light receiving element, and a second frequency converter group (50, 52) connected to the second light receiving element. The light emitted from the first light-emitting element is split into two parts, one of these is made incident onto the first light receiving element through a distance measuring optical path (23) for traveling to and from a target reflection object (22), and the other is made incident onto the second light receiving element through a first reference optical path (26), and the light emitted from the second light-emitting element is split into two parts, one of these is made incident onto the second light receiving element through a second reference optical path (31), and the other is made incident onto the first light receiving element through a third reference optical path (29).