Integrated Flood-Spot VCSEL Optics for Compact 3D Sensing

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Solution Overview

Problem

Existing 3D sensing technologies face challenges in miniaturization due to the excessive form factor of combined flood and spot illuminators, which limits their integration in devices like mobile phones, where they are required for both high-resolution close-distance sensing and long-distance sensing with lower resolution.

Innovation Solution

A compact VCSEL module is designed with a two-segment optics configuration, including a flood projector segment and a spot projector segment, which are positioned in close proximity to each other, allowing for a small form-factor emitter module that can project both flood and spot patterns without optical crosstalk, enabling integration into mobile devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If separate flood and spot illuminators are used to achieve both high-resolution close-distance sensing and long-distance sensing, then sensing capability is improved, but device form factor increases excessively

Engineering Contradiction:

Improvesensing capabilityVSAvoiddevice form factor

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent combines flood and spot illuminators into a single integrated VCSEL module with a unified substrate. Multiple VCSEL arrays (both flood and spot types) are arranged on the same substrate and share common optical components including collimating lenses, diffractive optical elements, and beam combining optics, eliminating the need for separate illuminator housings and reducing overall device footprint.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent implements a nested optical configuration where spot VCSEL arrays are positioned within or adjacent to flood VCSEL arrays on the same substrate. The optical paths are nested such that spot beams and flood beams share common optical components like collimating lenses and diffractive optical elements, with beam combining optics nesting the two beam types into a single integrated output structure.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Area of stationary object

If multiple VCSEL arrays are integrated on a common substrate to reduce form factor, then device compactness is improved, but optical crosstalk between flood and spot beams increases

Engineering Contradiction:

Improvemodule sizeVSAvoidoptical crosstalk

Core Design Contradiction:

Area of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The patent applies different optical characteristics to different regions of the VCSEL arrays and optical path. Flood VCSELs and spot VCSELs are designed with different emission patterns and wavelengths. Different optical elements (collimating lenses with specific focal lengths, diffractive optical elements with specific patterns) are assigned to different regions to optimize each beam type while minimizing interference. Beam combining optics are designed with spatial filtering characteristics that selectively combine beams while rejecting crosstalk.

Inventive Principle:

Principle #3Local quality

3Area of stationary object

If beam combining optics are used to reduce combined beam size, then aperture compatibility is improved, but optical power loss increases

Engineering Contradiction:

Improvecombined beam sizeVSAvoidoptical power

Core Design Contradiction:

Area of stationary objectVSLoss of energy

Solution Approach 1:

The patent replaces traditional mechanical beam combining methods (which rely on physical beam intersection and can cause significant power loss) with diffractive optical element-based beam combining. The diffractive optical elements manipulate light paths through diffraction and interference effects, enabling efficient spatial multiplexing of flood and spot beams without the mechanical losses associated with traditional beam combining approaches.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 achieves a combined flood-spot beam size suitable for mobile device apertures, maintaining maximum optical power and resolution while minimizing the module's size, thus enabling its inclusion in devices with limited space, such as smartphones and tablets.

Implementation Method 1

an optical diffuser positioned in front of the first collimating lens

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 2

a beamsplitter grating positioned in front of the second collimating lens

Methodology Applied

Scientific EffectDiffraction: Diffraction

Data Source

PatentUS11804695B2Integrated flood and spot illuminators

Publication Date: 2023.10.31 WELLS FARGO BANK NA

AI summary

In some implementations, an emitter module may include an emitter layer including a first emitter array configured to produce a first beam that provides flood illumination, and a second emitter array configured to produce a second beam that provides spot illumination. The emitter module may include a first optics layer, positioned in front of the emitter layer, that includes a first collimating lens positioned in front of the first emitter array, and a second collimating lens positioned in front of the second emitter array. The emitter module may include a second optics layer, positioned in front of the first optics layer, that includes an optical diffuser positioned in front of the first collimating lens, and a beamsplitter grating positioned in front of the second collimating lens.