Light-field projector using waveguide beam expansion

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Solution Overview

Problem

Conventional light-field projectors with arrays of spatially disparate light-sources are unable to construct a small form-factor, cost-efficient projector due to their large size and high manufacturing complexity.

Innovation Solution

A light-field projector design utilizing a light device with fewer light sources and an optical waveguide module that couples and expands collimated incident light-beams to illuminate a spatial light modulator, allowing for a smaller form factor, lower power consumption, and reduced manufacturing complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If arrays of spatially disparate light-sources are used to illuminate the SLM, then the light-field projector can form multiple viewpoints, but the device size and manufacturing complexity increase significantly

Engineering Contradiction:

Improveviewpoint formation capabilityVSAvoiddevice size and manufacturing complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple light sources into a single light source that sequentially generates light beams for different viewpoints. This merging approach eliminates the need for arrays of spatially disparate light sources, significantly reducing device size and manufacturing complexity while maintaining the capability to form multiple viewpoints through temporal multiplexing

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces dynamic elements including a tunable lens that adjusts focal length and a beam steering mechanism that changes light beam direction. These dynamic components enable a single light source to sequentially illuminate different regions of the SLM, creating multiple viewpoints over time rather than requiring simultaneous static light sources

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If arrays of spatially disparate light-sources are used, then multiple viewpoints can be formed, but power consumption increases

Engineering Contradiction:

Improveviewpoint formation capabilityVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent merges the function of multiple light sources into a single light source that operates sequentially. This consolidation reduces total power consumption because only one light source needs to be active at any given time, while still achieving the same viewpoint formation capability through time-multiplexed illumination

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent employs periodic action by having the single light source sequentially generate light beams for different viewpoints in a time-multiplexed manner. The tunable lens and beam steering mechanism are also modulated periodically to direct light to the appropriate SLM regions, enabling multiple viewpoints to be formed through temporal sequencing rather than simultaneous illumination

Inventive Principle:

Principle #19Periodic action

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 a compact, cost-efficient light-field projector capable of producing a 3D rendering with a smaller footprint, achieving the same image quality as conventional projectors while reducing power consumption and manufacturing costs.

Implementation Method 1

a collimating element configured to collimate the incident light-beam

Methodology Applied

Scientific EffectCollimation: Lens

Implementation Method 2

an input grating configured to couple the collimated incident light-beam to the waveguide

Methodology Applied

Scientific EffectGrating coupling: Diffraction Grating

Implementation Method 3

an optical waveguide module comprising a waveguide including an input grating configured to couple the collimated incident light-beam to the waveguide

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 4

an exit grating configured to outcouple the collimated incident light-beam from the waveguide and generate a plurality of expanded light-beams

Methodology Applied

Scientific EffectGrating diffraction: Diffraction Grating

Implementation Method 5

an optical light modulator having a modulator surface area and configured to modulate the collimated incident light-beam

Methodology Applied

Scientific EffectPhase modulation: Phase Modulation

Data Source

PatentUS20240231121A1Light-field projector having a small form factor

Publication Date: 2024.07.11 CREAL

AI summary

Light-field projector for projecting an image, the light-field projector comprising a light device (1) comprising at least one light source (10-12) sequentially generating an incident light-beam (101, 102): a collimating element (20) configured to collimate the incident light-beam (101, 102); and an optical light modulator (3) having a modulator surface area and configured to modulate the collimated incident light-beam (101, 102) and to project a modulated light-beam (201, 202). The light-field projector further comprises an optical waveguide module (30) comprising a waveguide (303) including an input grating (301) configured to couple the collimated incident light-beam (101, 102) to the waveguide (303), and an exit grating (302) configured to outcouple the collimated incident light-beam (101, 102) from the waveguide (303) and generate a plurality of expanded light-beams (201, 202); the plurality of expanded light-beam (201, 202) sequentially illuminating substantially the whole modulator surface area.