Phase-Modulated Spatial Light Modulator Distance Measurement
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Solution Overview
Problem
Existing distance measurement devices face challenges in accurately detecting target objects in light projection areas due to interference from reflected light and the need for multiple projectors or fixed light patterns, which limits their ability to adapt to changing conditions and maintain high resolution across varying distances.
Innovation Solution
A distance measurement system employing a phase-modulation-type spatial light modulator that projects light patterns with specific phase distributions onto multiple projection areas, allowing for accurate detection and measurement of target objects by analyzing imaging data and controlling light emission to verify object presence and calculate distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple projectors are mounted to eliminate blind spots and improve coverage, then the measurement range and detection capability are improved, but the device complexity and cost increase
Solution Approach 1:
The patent divides the light projection task into multiple wavelength segments. A single projector emits light at multiple wavelengths (e.g., 405nm, 450nm, 530nm, 630nm), with each wavelength serving a specific distance range. This segmentation allows one projector to cover the full measurement range that would otherwise require multiple projectors, resolving the contradiction between measurement range and device complexity.
2Reliability
If laser is continued to be radiated onto an entire surface to ensure coverage, then the measurement reliability is improved, but the power consumption increases
Solution Approach 1:
The patent applies local quality by assigning different wavelengths to different spatial regions (distance ranges). Each wavelength is concentrated on its optimal detection range rather than spreading all wavelengths uniformly across the entire surface. This localized approach maintains detection reliability in each zone while significantly reducing total power consumption compared to uniform full-surface illumination.
Solution Approach 2:
The system uses periodic wavelength switching or pulsed emission at different wavelengths sequentially rather than continuous full-spectrum radiation. This periodic action allows the same optical components to serve multiple wavelength functions over time, reducing instantaneous power requirements while maintaining comprehensive coverage reliability.
3Device complexity
If a single projector is used to reduce device complexity, then the device simplicity is improved, but the ability to cover large ranges with high resolution deteriorates
Solution Approach 1:
The patent changes the wavelength parameter of the light source to achieve different resolution characteristics. By selecting appropriate wavelengths for different distance ranges (shorter wavelengths for longer distances, longer wavelengths for closer ranges), a single projector can maintain high resolution across the entire measurement range, overcoming the limitation of single-projector systems that typically compromise resolution for extended range coverage.
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 system reliably detects target objects and measures distances with improved power efficiency and resolution, capable of adapting to different conditions without the need for multiple projectors or fixed patterns, enhancing accuracy and adaptability.
Implementation Method 1
a light emitting device (10) including a spatial light modulator element (13), and configured to emit projected light for forming a pattern associated with a phase distribution displayed on a display part of the spatial light modulator element
Implementation Method 2
a light receiving device (20) for capturing an area including a pattern to be formed by projected light emitted by the light emitting device
Data Source
AI summary
In order to reliably detect a target object located within a projection area and measure a distance to the detected target object, a distance measurement system includes: a light emitting device including a phase-modulation-type spatial light modulator element, and configured to emit projected light for forming a pattern associated with a phase distribution displayed on a display part of the spatial light modulator element, toward at least two projection areas; a light receiving device for capturing an area including a pattern to be formed by projected light emitted by the light emitting device; and a control device for controlling light emission from the light emitting device, verifying, for each projection area, presence or absence of a target object within the projection area by analyzing imaging data captured by the light receiving device, and measuring a distance to a detected target object.