Optical Measuring Device With Dome-Encapsulated MEMS Micromirror
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical measuring devices for spatially resolved distance determination lack a compact design, long service life, reliable function under strong background light, high spatial resolution, large measurement range, and high measurement speed, particularly when used in mobile electronic systems.
Innovation Solution
An optical measuring device featuring a MEMS-based scanning unit with a micromirror, a prism unit, and a photodetector arranged on a common substrate, utilizing a dome-shaped window for coaxial propagation of scanning and detection light, and encapsulating the micromirror to reduce environmental influences, enabling efficient distance determination with improved signal-to-noise ratio and reduced energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the laser light source, photodetector, and scanning unit are arranged on a common planar substrate, then the device achieves a compact design, but the optical path alignment and signal quality become more difficult to maintain
Solution Approach 1:
The patent introduces a three-dimensional optical path structure using a beam splitter prism and multi-layer substrate arrangement. The optical axis extends in multiple dimensions (first section in first direction, second section in second direction), allowing compact planar integration while maintaining proper optical alignment through spatial separation in different dimensions.
Solution Approach 2:
The beam splitter prism acts as an intermediary optical element that separates and directs the optical paths of scanning light and detection light. This mediator component enables independent optimization of each optical path while maintaining their coaxial relationship, resolving the alignment stability issue in compact designs.
2Duration of action of stationary object
If the micromirror is encapsulated in an airtight manner between the dome-shaped window and the substrate, then the service life is extended by reducing environmental influences, but the manufacturing complexity increases
Solution Approach 1:
The micromirror is nested within an airtight encapsulation structure formed by the dome-shaped window and substrate. This nested configuration protects the micromirror from environmental influences (humidity, oxygen) while maintaining a compact integrated structure that can be manufactured using standard MEMS fabrication processes.
Solution Approach 2:
The airtight encapsulation creates an inert environment around the micromirror, isolating it from degrading environmental factors. This extends the service life of the micromirror by preventing oxidation and other environmental degradation, while the encapsulation structure itself is designed to be compatible with conventional manufacturing methods.
3Volume of moving object
If the second section of the optical axis includes an angle of incidence greater than 0 degrees and smaller than 90 degrees with the substrate surface, then the optical path is optimized for compact design, but the alignment precision becomes more challenging
Solution Approach 1:
The optical axis is configured to extend in multiple dimensions rather than parallel to the substrate surface. The second section of the optical axis extends in a second direction at an optimized angle, utilizing three-dimensional spatial arrangement to achieve compact footprint while maintaining alignment precision through geometric optimization.
Solution Approach 2:
The angle of incidence of the second optical axis section is optimized within the range greater than 0 and smaller than 90 degrees. This parameter optimization balances compact device volume with manufacturable alignment precision, avoiding the extremes of parallel (0 degrees) or perpendicular (90 degrees) configurations.
4Measurement precision
If the prism unit is used to apply scanning light to the micromirror and detection light to the photodetector coaxially, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The beam splitter prism performs multiple functions: it separates the scanning light path from the detection light path, directs both beams coaxially to/from the micromirror, and enables compact integration of all optical components. This multi-functional component reduces the need for separate alignment elements, thereby reducing overall device complexity while maintaining high spatial resolution.
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 device achieves high spatial resolution and measurement speed over a large range while maintaining a compact design, ensuring reliable operation even under strong background light conditions, with enhanced service life and energy efficiency.
Implementation Method 1
a micromirror pivotable about at least one axis for the deflection of the scanning light emitted by the laser light source into an object space and a drive for pivoting the micromirror about the at least one axis; a photodetector, configured to detect a portion of a detection light incident coaxially to the scanning light deflected by the micromirror and reflected at the micromirror
Implementation Method 2
a prism unit, configured to apply the scanning light emitted by the laser light source to the micromirror so that the scanning light is reflected into the object space at the micromirror and to apply the portion of the detection light reflected at the micromirror to the photodetector so that the scanning light and the detection light propagate coaxially
Implementation Method 3
the scanning unit comprises a dome-shaped window passed through by the second section of the optical axis and transmitting the detection light
Data Source
AI summary
The invention relates to an optical measuring device (1) for spatially resolved distance determination, comprising: a laser light source (2), a scanning unit (4) comprising a micromirror (5) for the deflection of a scanning light (3) emitted by the laser light source (2); a photodetector (8) to detect a detection light (9) incident coaxially to on the scanning light (3); a prism unit (10) to apply scanning light (3) to the micromirror (5) and the detection light (9) to the photodetector (8), wherein the laser light source (2), the photodetector (8), and the scanning unit (4) are arranged on a common substrate (13); the scanning unit (4) comprises a dome-shaped window (14) below which the micromirror (5) is encapsulated in an airtight manner; and the prism unit (10) comprises: a first surface (15) to reflect the scanning light (3); a second surface (17) to reflect the detection light (9) to the photodetector (8) and to transmit the scanning light (3); and a third surface (18) to transmit and/or deflect the scanning light (3) and to transmit and/or deflect the detection light (9).