Surveying Instrument Light Receiver Miniaturization
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Solution Overview
Problem
The miniaturization of surveying instruments' light receivers is hindered by the size and focal distance requirements of their optical systems, particularly for long-distance measurements, making it difficult to reduce their size effectively.
Innovation Solution
The surveying instrument incorporates a light amount adjusting member with a multilayer film optical element and a receiving prism that internally reflects and separates distance measuring light and tracking light, allowing for a shared optical path and reduced component count, enabling miniaturization by adjusting the light receiving amount based on emission repetition frequency and peak power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the aperture of the lens is increased to assure light receiving amount for long-distance measurement, then the light receiving capability is improved, but the size and focal distance of the optical system increase, making miniaturization difficult
Solution Approach 1:
The patent introduces a light amount adjusting member that can be inserted into or removed from the optical path, allowing dynamic control of light receiving amount without changing the fundamental optical system size. This dimensional addition (adjustable element) resolves the contradiction by providing flexibility in light control while maintaining compact form factor.
Solution Approach 2:
The light amount adjusting member enables dynamic adjustment of light receiving amount based on measurement conditions (short-distance vs. long-distance measurement). By making the optical system adaptable rather than fixed, the patent allows optimization of light receiving capability for different scenarios without permanently increasing the device size.
2Measurement precision
If the focal distance is increased to accommodate the lens for long-distance measurement, then the measurement capability is improved, but the optical axis length increases, hindering miniaturization
Solution Approach 1:
The optical system is segmented into fixed components (lens, photodetector) and adjustable components (light amount adjusting member). This segmentation allows the focal distance to be optimized for measurement capability while the adjustable member compensates for variations in light receiving amount, effectively decoupling the two parameters and allowing miniaturization.
Solution Approach 2:
The patent changes the parameter of light receiving amount adjustability by introducing the light amount adjusting member. This parameter change allows the system to maintain optimal measurement capability with shorter focal distances, as the light receiving amount can be adjusted rather than requiring a longer focal length to achieve sufficient light collection.
3Adaptability or versatility
If separate optical paths are used for distance measuring light and tracking light, then the measurement functions are independent, but the device complexity and component count increase
Solution Approach 1:
The patent merges the optical paths for distance measuring light and tracking light by using a single receiving prism and light amount adjusting member for both functions. The beam splitter separates the lights at the source, but they share common optical components during reception, reducing overall device complexity while maintaining functional independence.
Solution Approach 2:
The receiving prism and light amount adjusting member serve multiple functions: they handle both distance measuring light and tracking light, and can be adjusted for different measurement conditions. This multi-functionality reduces the total component count while maintaining the ability to perform both measurement functions independently when needed.
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 configuration allows for the shortening of the optical axis lengths of the light receivers, achieving miniaturization while maintaining measurement accuracy and flexibility in light reception, especially during both short and long-distance measurements.
Implementation Method 1
a receiving prism provided on a common optical path of the reflected distance measuring light and the reflected tracking light which have been transmitted through the second deflecting optical member, and the receiving prism is configured to internally reflect the reflected distance measuring light and the reflected tracking light more than once, then separate the reflected distance measuring light from the reflected tracking light
Implementation Method 2
a beam splitter film having a predetermined reflectance is formed on an incidence portion of the second incidence surface of the distance measuring light and the tracking light, an antireflective film is formed on portions excluding the beam splitter film, the distance measuring light and the tracking light are reflected by the beam splitter film, and the reflected distance measuring light and the reflected tracking light transmit through the beam splitter film and the antireflective film
Implementation Method 3
the light amount adjusting member is configured to adjust a light receiving amount of the reflected distance measuring light in correspondence with the emission repetition frequency and the peak power of pulses
Data Source
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AI summary
Provided is a surveying instrument including a distance measuring light projector configured to project a distance measuring light to an object, a distance measuring light receiver having a photodetector configured to receive a reflected distance measuring light from the object, a tracking light projector configured to project a tracking light to the object, and a tracking light receiver having a tracking photodetector configured to receive a reflected tracking light from the object, in which the distance measuring light receiver and the tracking light receiver have a receiving prism, and the receiving prism is configured to internally reflect the reflected distance measuring light and the reflected tracking light more than once, then separate the reflected distance measuring light from the reflected tracking light, cause the reflected distance measuring light and the reflected tracking light to be received by the photodetector and the tracking photodetector.