Hybrid Refractive-Diffractive Dot Projector for Spot Aberration Correction

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Solution Overview

Problem

Conventional dot projectors with a total module height constraint suffer from spot aberrations for off-axis or diagonal dots due to limited physical space, leading to blurred or overlapping dots at the projection surface, and adding additional refractive surfaces increases z-height, cost, and complexity.

Innovation Solution

A dot projector incorporating hybrid refractive-diffractive optical elements with a periodic optical phase function for light replication and an aberration-correcting phase function to correct spot aberrations, allowing for a total optics length shorter than the effective focal length of collimating elements while maintaining performance and adhering to z-height constraints.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If additional refractive surfaces are added to correct spot aberrations, then spot aberration correction is improved, but z-height increases and device complexity increases

Engineering Contradiction:

Improvespot aberration correctionVSAvoidz-height

Core Design Contradiction:

Manufacturing precisionVSLength of moving object

Solution Approach 1:

The patent changes the optical parameter approach by using a hybrid refractive-diffractive optical element where the diffractive phase function provides aberration correction without requiring additional refractive surfaces. The diffractive optical element modifies the wavefront phase directly through diffraction, achieving aberration correction while maintaining a compact z-height profile.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite optical element that combines refractive and diffractive functionalities in a single component. The hybrid element integrates a refractive substrate with a diffractive phase function, allowing both collimation and aberration correction in one element without stacking multiple separate optical components.

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If additional refractive surfaces are added to correct spot aberrations, then spot aberration correction is improved, but device complexity increases

Engineering Contradiction:

Improvespot aberration correctionVSAvoidnumber of components

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges multiple optical functions into a single hybrid refractive-diffractive element. The element simultaneously performs collimation, beam replication, and aberration correction that would traditionally require multiple separate optical components, thereby reducing device complexity while maintaining correction performance.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The hybrid optical element is designed to perform multiple functions: collimating the VCSEL light, replicating the beam into multiple dots, and correcting spot aberrations. This multi-functional design eliminates the need for separate correction optics, reducing overall device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Length of moving object

If the optics length is reduced below the effective focal length of collimating elements, then z-height constraint is satisfied, but optical performance may deteriorate

Engineering Contradiction:

Improveoptics lengthVSAvoidoptical performance

Core Design Contradiction:

Length of moving objectVSReliability

Solution Approach 1:

The patent uses diffractive phase modulation to achieve aberration correction at shorter optics lengths. The diffractive element's phase function is specifically designed to compensate for aberrations introduced by the reduced optical path length, maintaining diffraction-limited performance despite the compact form factor.

Inventive Principle:

Principle #35Parameter changes

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 provides aberration correction, ensuring diffraction-limited performance and satisfying z-height constraints without significantly increasing the number of components, cost, or complexity, while achieving a total optics length less than the effective focal length of collimating elements.

Implementation Method 1

one or more collimating elements to collimate light emitted by the VCSEL chip

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

an optical element including a periodic optical phase function to replicate the light after collimation

Methodology Applied

Scientific EffectDiffraction: Diffraction

Data Source

PatentUS12188763B2Dot projector including hybrid refractive-diffractive optical elements

Publication Date: 2025.01.07 WELLS FARGO BANK NA

AI summary

A dot projector may include a vertical-cavity surface-emitting laser (VCSEL). The dot projector may include one or more collimating elements to collimate light emitted by the VCSEL. An effective focal length of the one or more collimating elements may be larger than an optics length of the dot projector. The dot projector may include an optical element including a periodic optical phase function to replicate the light after collimation by the one or more collimating elements and an aberration-correcting phase function to correct spot aberrations in a dot pattern resulting from the tiling or splitting of the light.