MEMS Deflection Unit for Optical Distance Measurement
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Solution Overview
Problem
Existing optical distance measuring apparatuses face challenges in accurately measuring distances to desired positions without altering the collimation direction, particularly due to the lack of specific configurations for micro scanner elements and efficient beam path manipulation.
Innovation Solution
The optical distance measuring apparatus employs a deflection unit with MEMS mirrors and a telecentric optical system, allowing for precise adjustment of the distance measurement emission light's direction and inclination, enabling measurement without changing the collimation direction by using a diffuser unit to switch between reduced and enlarged irradiation points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a micro scanner element is used to change beam path for measuring distance to desired position, then the distance measurement capability is improved, but the device complexity increases and specific configuration details are lacking making practical implementation difficult
Solution Approach 1:
The patent segments the beam path modification function into two independent components: a deflection unit with MEMS mirrors for directional control and a diffuser unit for spot size control. This segmentation allows each component to be optimized independently and simplifies the overall configuration by dividing the complex beam path manipulation into manageable functional modules.
Solution Approach 2:
The patent introduces a telecentric optical system as an intermediary between the deflection unit and the objective lens. This intermediary optical system ensures that the beam path changes produced by the MEMS mirrors are properly transferred to the measurement beam without introducing angular errors, thereby maintaining measurement precision while simplifying the control requirements.
2Adaptability or versatility
If the collimation direction is changed to measure distance to different positions, then the measurement flexibility is improved, but the measurement precision deteriorates because the collimation direction cannot remain fixed
Solution Approach 1:
The patent separates the functions of directional control and collimation by placing the deflection unit (MEMS mirrors) in the measurement beam path while keeping the collimation optical system fixed. This allows the beam direction to be changed for measuring different positions while the collimation direction remains constant, maintaining measurement precision through proper optical design.
Solution Approach 2:
The patent replaces mechanical rotation of the entire optical system with an electro-optical deflection system using MEMS mirrors. This substitution allows rapid and precise beam direction control without mechanically moving the collimation system, thereby maintaining measurement precision while improving flexibility and response speed.
3Ease of operation
If the apparatus size is reduced for portability, then the ease of operation is improved, but the measurement precision may deteriorate due to constraints on optical component dimensions
Solution Approach 1:
The patent replaces bulky mechanical scanning systems with compact MEMS mirror-based deflection units. This substitution dramatically reduces the size of the beam path control mechanism while maintaining precise angular control capability, thereby improving portability without sacrificing measurement precision.
Solution Approach 2:
The patent employs thin-film MEMS mirror structures that provide high-precision angular deflection in a extremely compact form factor. These thin-film devices enable precise beam control in a minimal space, allowing the apparatus to be made portable while maintaining the optical precision required for accurate distance measurement.
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 allows for accurate distance measurement to desired positions within the visual field without altering the collimation direction, enhancing measurement precision and flexibility while reducing the apparatus's size and power consumption.
Implementation Method 1
a deflection unit 34 which changes a light flux traveling direction; the deflection unit 34 includes MEMS mirrors
Implementation Method 2
using a diffuser unit to switch between reduced and enlarged irradiation points
Implementation Method 3
an objective lens group 41 which emits the distance measurement emission light Es as a light flux parallel to an irradiation light axis Li
Implementation Method 4
measuring a time difference and/or phase difference between the emission light and the reflection light
Data Source
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AI summary
An optical distance measuring apparatus which emits emission light from a light source to an object and receives reflection light from the object with a light-receiving unit, and performs distance measurement based on the emission light and the reflection light, the apparatus including a deflection mechanism provided in an optical path to an irradiation light axis from the light source to the object, the deflection mechanism configured to reflect the emission light to incline a direction of the emission light with respect to the emission light axis of the light source, wherein the deflection mechanism has an optically conjugate relationship with a predetermined position on the emission light axis or on the irradiation light axis, the predetermined position being closer to the object than the deflection mechanism when viewed from the light source.