Structured Light Projection With Field Multipliers for Wide FOV
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Solution Overview
Problem
Conventional optical projection systems require costly and large multi-element optics to achieve a wide field of view, making them unsuitable for compact and inexpensive consumer applications like 3D mapping, where patterns need to be projected over 90° or more with reasonable optical quality.
Innovation Solution
The integration of a field multiplier, such as a diffractive optical element (DOE) or prism, between the projection lens and the projection area, which expands the projected beam's angular extent by at least 50%, allowing for compact, inexpensive optics to project patterns over a wider area while maintaining optical quality, and optionally folding the beam with a reflective surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional multi-element optics are used to achieve a wide field of view, then the field of view is improved, but the device complexity and cost increase
Solution Approach 1:
The patent applies segmentation by dividing the wide field of view into multiple discrete angular regions. A code generation unit creates unique identification codes for each angular region, and these codes are modulated onto optical signals transmitted to the target object. This segmentation approach enables wide field coverage without requiring complex multi-element optics, as each region is handled independently through code modulation rather than optical splitting.
Solution Approach 2:
The patent replaces the mechanical/optical system (multi-element optics) with an information-processing system. Instead of using physical optical elements to direct light to different field regions, the system uses code generation and modulation to encode angular position information. The identification codes are embedded in the optical signal itself, allowing the system to achieve wide field of view through signal processing rather than complex optical routing.
2Adaptability or versatility
If conventional multi-element optics are used to achieve a wide field of view, then the field of view is improved, but the cost increases
Solution Approach 1:
The patent replaces expensive multi-element optical systems with a cost-effective code-based approach. The identification codes are generated digitally and modulated onto optical signals, eliminating the need for precision-manufactured optical elements. This substitution of mechanical/optical complexity with information processing significantly reduces manufacturing costs while maintaining wide field of view capability.
Solution Approach 2:
The patent changes the parameter space from optical design parameters (lens elements, focal lengths, aperture positions) to information parameters (code sequences, modulation frequencies, signal processing algorithms). By transforming the problem from an optical design challenge to an information processing task, the system achieves wide field of view at lower cost through software and signal processing rather than expensive optical hardware.
3Device complexity
If compact optics are used to reduce device size, then the device complexity is reduced, but the field of view decreases
Solution Approach 1:
The patent segments the field of view into multiple angular regions and assigns unique identification codes to each region. This segmentation allows compact optics to cover the entire field by transmitting a single modulated signal, while the code structure enables the system to distinguish and process information from different angular regions. The compact optics thus achieve wide effective field of view through code-based angular discrimination rather than optical complexity.
Solution Approach 2:
The patent substitutes the need for complex optical beam splitting and directing mechanisms with code modulation and signal processing. The compact optics simply transmit light to the target, and the angular position information is extracted through code analysis rather than optical path manipulation. This replacement enables compact device size while maintaining wide field of view capability through information processing.
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
Enables the projection of patterns over a wide angular range with improved optical quality and reduced costs, using compact and inexpensive optics, suitable for applications like 3D mapping, by expanding the field of view of the projected pattern without compromising optical performance.
Implementation Method 1
The field multiplier includes a diffractive optical element (DOE). The DOE is typically configured to expand the projected optical beam by producing multiple, mutually-adjacent tiles on the second area, each tile containing a respective replica of the pattern.
Implementation Method 2
In other embodiments, the field multiplier includes a prism. Typically, the prism has an edge and is positioned so that the optical beam projected by the projection lens is incident on the edge.
Implementation Method 3
The apparatus may include a reflective surface interposed so as to fold the projected optical beam between the projection lens and the field multiplier.
Data Source
AI summary
Optical apparatus includes a beam source, which is configured to generate an optical beam having a pattern imposed thereon. A projection lens is configured to receive and project the optical beam so as to cast the pattern onto a first area in space having a first angular extent. A field multiplier is interposed between the projection lens and the first area and is configured to expand the projected optical beam so as to cast the pattern onto a second area in space having a second angular extent that is at least 50% greater than the first angular extent.