MEMS Distance Measuring Device with Segmented Light Reception
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Solution Overview
Problem
Current distance measuring devices, such as those using MEMS mirrors, face challenges in expanding measurement range due to small deflection angles, increased cost, and difficulty in distinguishing laser beams from noise light, while also needing to be downsized for applications like smartphones.
Innovation Solution
A distance measuring device with a light projection unit that emits a two-dimensional laser beam using a MEMS mirror for one-dimensional scanning, combined with a light receiving unit and control unit to manage light reception, allowing for increased measurement range and cost-effectiveness by overlapping laser beams to enhance light intensity within safety standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a MEMS mirror is used to downsize the optical configuration, then the device size is reduced, but the deflection angle becomes small and the amount of received light cannot be increased
Solution Approach 1:
The patent divides the light receiving function into multiple light receiving elements (first light receiving element and second light receiving element) positioned at different locations. This segmentation allows each element to capture light reflected at different angles, effectively increasing the total amount of received light while maintaining the compact MEMS mirror design.
Solution Approach 2:
The patent combines the light receiving functions of multiple light receiving elements to achieve the same effect as a larger deflection angle. By merging the captured light signals from different elements, the system increases the total received light amount without requiring a larger MEMS mirror deflection angle.
2Measurement precision
If the light intensity of the laser beam incident on the MEMS mirror is increased to expand the distance measurement range, then the measurement range is expanded, but the laser beam safety standard may not be satisfied
Solution Approach 1:
The patent segments the light receiving function across multiple elements positioned to capture light at different angles. This allows the system to use multiple lower-intensity laser beams instead of a single high-intensity beam, expanding the measurement range while maintaining safety standards by distributing the optical energy.
Solution Approach 2:
The patent transitions from a single light receiving path to multiple spatial paths by positioning light receiving elements at different locations. This dimensional expansion allows the system to collect light from multiple angles simultaneously, effectively increasing the measurement range without increasing the intensity of individual laser beams.
3Measurement precision
If a polygon mirror is used to increase the deflection angle, then the distance measurement range is expanded, but downsizing is difficult and in-vehicle reliability is compromised
Solution Approach 1:
The patent uses multiple light receiving elements positioned at different angles to compensate for the small deflection angle of the MEMS mirror. This segmentation approach allows the compact MEMS mirror to achieve the functional equivalent of a larger deflection angle system, maintaining reliability while expanding measurement range.
Solution Approach 2:
The patent creates multiple virtual light receiving paths by positioning light receiving elements at different locations, effectively copying the light reception function across multiple spatial positions. This allows the compact MEMS mirror to achieve the performance of a larger mirror system without the associated reliability issues.
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 enables a wider measurement range while maintaining safety standards and reducing costs, improving the accuracy and reliability of distance measurements by increasing light intensity and reducing noise interference.
Implementation Method 1
a micro electro mechanical system (MEMS) mirror that controls a traveling direction of the laser beam having passed through the optical system
Implementation Method 2
a light receiving unit including a plurality of light receiving elements arranged in a two-dimensional direction
Implementation Method 3
a light projection unit that emits light in a two-dimensional manner
Data Source
AI summary
Downsizing is possible, and a distance measurement range can be expanded while satisfying a safety standard of laser beam. A distance measuring device includes a light projection unit that emits light in a two-dimensional manner, a light receiving unit including a plurality of light receiving elements arranged in a two-dimensional direction, and a control unit that controls whether or not to perform light reception by the plurality of light receiving elements.