Dot Pattern Projector for 3D Distance Measurement
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Solution Overview
Problem
Three-dimensional optical distance measurement systems based on time-of-flight technology face limitations due to the short projection distance of flood illuminators with weak optical energy, necessitating a solution for high-power illumination patterns with extended projection capabilities.
Innovation Solution
A dot pattern projector comprising a light source array, a lens, and a diffracting unit, such as a microlens array or diffraction optical element, which overlaps or interlaces illumination patterns from multiple light sources to produce high-power, regularly distributed dot patterns for extended projection distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a flood illuminator is used for three-dimensional optical distance measurement, then the system can provide distance measurement coverage, but the projection distance is limited due to weak optical energy
Solution Approach 1:
The invention divides the illumination system into multiple light sources arranged in an array, where each light source projects its own dot pattern. By segmenting the illumination task across multiple sources, the system achieves both high optical energy output and extended projection distance while maintaining measurable dot patterns for depth calculation.
2Power
If multiple light sources are used to increase optical energy, then illumination intensity improves, but the complexity of the device increases
Solution Approach 1:
The patent employs a microlens array that serves multiple functions: it collimates light from each light source, diffracts the collimated light into dot patterns, and maintains a one-to-one correspondence between light sources and microlenses. This multi-functionality reduces device complexity while achieving high illumination power through multiple light sources.
3Shape
If a microlens array is used to diffract light, then dot patterns can be projected with regular distribution, but the manufacturing precision requirements increase
Solution Approach 1:
The patent performs preliminary collimation of light from each light source using individually corresponding microlenses before the light reaches the diffracting unit. This preliminary action ensures that the light incident on the diffracting unit is already collimated, which relaxes the manufacturing precision requirements for achieving regular dot pattern distribution while maintaining shape quality.
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 high-power illumination patterns with significantly increased projection distances, enhancing the flexibility and fabrication of the dot pattern projector, and when combined with a flood illuminator, improves the depth measurement capabilities of three-dimensional optical distance measurement systems.
Implementation Method 1
The lens is configured to collimate the light beams
Implementation Method 2
The diffracting unit is configured to diffract the collimated light beams thereby to project an illumination pattern
Data Source
AI summary
A dot pattern projector includes a light source array, a lens and a diffracting unit. The light source array includes a plurality of light sources that emit light beams. The lens is configured to collimate the light beams. The diffracting unit is configured to diffract the collimated light beams thereby to project an illumination pattern, wherein the illumination pattern is formed by overlapping multiple dot patterns that are projected by different light sources or interlacing multiple dot patterns that are projected by different light sources.