Distance Measuring Instrument Bias Voltage Sensitivity Control
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Solution Overview
Problem
Existing distance measuring instruments face errors due to deviations between the distance measuring optical axis and the prism optical axis, particularly in prism mode measurements, leading to inaccurate distance calculations and requiring high-quality photodetecting units to maintain measurement accuracy, which increases costs and reduces yield.
Innovation Solution
A distance measuring instrument that adjusts photodetecting sensitivity using a control arithmetic unit and sensitivity adjusting unit, by changing the bias voltage impressed on the photodetecting unit, allowing for accurate measurements even when the distance measuring optical axis is deviated from the prism optical axis, and enabling seamless switching between prism and non-prism modes without the need for high-quality photodetecting units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-quality photodetecting unit with uniform sensitivity over the light receiving surface is used, then measurement accuracy is maintained even when the distance measuring optical axis deviates from the prism optical axis, but manufacturing cost increases and yield decreases
Solution Approach 1:
The patent changes the electrical parameter (bias voltage) of the photodetecting unit to adjust its sensitivity characteristics. By controlling the bias voltage within a specific range (0.6 to 0.8 times the breakdown voltage), the photodetecting unit achieves sufficient measurement accuracy without requiring high manufacturing precision, thus resolving the contradiction between measurement accuracy and ease of manufacture
Solution Approach 2:
The patent introduces dynamic adjustment of the bias voltage based on operating conditions (prism mode vs. non-prism mode, distance measurements). This dynamic control allows the system to adapt sensitivity requirements to actual measurement needs, maintaining accuracy while allowing use of lower-cost photodetecting units
2Adaptability or versatility
If the distance measuring optical axis is deviated from the prism optical axis, then automatic sighting function or heat haze conditions occur, but measurement error increases
Solution Approach 1:
The patent implements feedback control by measuring the actual light amount received and comparing it with expected values. The control unit adjusts the bias voltage based on this feedback to compensate for deviations, maintaining measurement accuracy even when the optical axis deviates due to automatic sighting or environmental conditions
Solution Approach 2:
The patent dynamically changes the bias voltage parameter in response to optical axis deviations. By adjusting this electrical parameter, the system compensates for the effects of deviation and maintains measurement precision while preserving adaptability to different sighting conditions
3Length of stationary object
If photodetecting sensitivity is increased to improve long-distance measurement capability, then measurement range extends, but measurement error increases when optical axis deviation occurs
Solution Approach 1:
The patent uses dynamic adjustment of bias voltage to optimize the balance between sensitivity and accuracy. In prism mode where high sensitivity is needed for long distances, the bias voltage is set to achieve maximum sensitivity. When optical axis deviation occurs, the system dynamically adjusts the voltage to reduce the impact of deviation, maintaining both extended range and acceptable precision
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
The solution allows for accurate distance measurements with reduced errors and lower manufacturing costs, as it adjusts sensitivity based on light amount and focusing conditions, ensuring high accuracy across various measurement modes without the need for high-quality photodetecting units.
Implementation Method 1
a photodetecting unit (14) for receiving and detecting a reflected distance measuring light and a part of the distance measuring light emitted from the distance measuring light emitting unit (13) as internal reference light
Implementation Method 2
a sensitivity adjusting unit (23) for adjusting photodetecting sensitivity of the photodetecting unit (14) by changing a bias voltage impressed to the photodetecting unit (14)
Implementation Method 3
a distance measuring light emitting unit (13) for emitting a distance measuring light
Data Source
Figure 1
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Figure 3A~3F
AI summary
The invention provides a distance measuring instrument, comprising a light emitting unit 13 for emitting a distance measuring light, a photodetecting unit 14 for receiving and detecting a reflected distance measuring light from an object to be measured and a part of the distance measuring light emitted from the light emitting unit as an internal reference light, a sensitivity adjusting unit 23 for electrically adjusting photodetecting sensitivity of the photodetecting unit, and a control arithmetic unit 22 for calculating a measured distance based on a photodetection signal of the reflected distance measuring light from the photodetecting unit and based on a photodetection signal of the internal reference light, wherein the control arithmetic unit can measure a distance by selecting a prism mode measurement and a non-prism mode measurement, and controls so that photodetecting sensitivity of the photodetecting unit is changed by the sensitivity adjusting unit in response to the selected measurement mode.