Projection Device Free-Form Optical Channels

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Solution Overview

Problem

Current projection technologies face challenges in miniaturization, leading to reduced luminous flux and power efficiency, and are limited in generating high-resolution light distributions due to intolerance to non-collimated input light sources and smearing effects, especially when trying to project fine structures.

Innovation Solution

A projection device using an array of optical channels with two refractive optical free-form surfaces that apply Köhler illumination to create a light object structure, allowing for the generation of high-resolution light distributions without blurring effects, even with divergent or non-collimated light, by redistributing light angularly and enhancing irradiance through transmission-modulated structures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If miniaturization of projection optics is performed, then the optical height is reduced, but the luminous flux transmission is reduced

Engineering Contradiction:
Improveoptical heightVSAvoidluminous flux transmission
Core Design Contradiction:
Length of moving objectVSLoss of energy

Solution Approach 1:

The projection system is divided into multiple optical channels arranged in an array, each channel containing free-form surfaces that redirect light from different regions of the light source. This segmentation allows the system to maintain compact dimensions while preserving overall luminous flux transmission through parallel light paths

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from single-channel to multi-channel array architecture, adding spatial dimensionality to the optical system. Multiple optical channels are arranged in a two-dimensional array, enabling the system to achieve both miniaturization and high luminous flux transmission by utilizing multiple parallel light paths

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Loss of energy

If free-form light redistribution is used, then power efficiency is improved, but the system is intolerant to real input light distributions causing smearing effects

Engineering Contradiction:
Improvepower efficiencyVSAvoidlight distribution precision
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The light source is divided into multiple regions, with each region feeding into a separate optical channel with dedicated free-form surfaces. This segmentation allows each channel to handle a specific portion of the light distribution, reducing the sensitivity to input variations and eliminating smearing effects while maintaining high power efficiency

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each optical channel is designed with locally optimized free-form surfaces tailored to its specific input light characteristics. This local optimization allows each channel to efficiently process its designated light portion while being tolerant to variations in the overall input distribution, preventing smearing across the entire system

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If absorptive structures are used for projection, then light distribution control is improved, but power transmission is reduced

Engineering Contradiction:
Improvelight distribution controlVSAvoidpower transmission
Core Design Contradiction:
Manufacturing precisionVSLoss of energy

Solution Approach 1:

The patent replaces absorptive mechanical structures with refractive free-form optical surfaces that redirect light through refraction. This substitution eliminates light absorption losses while maintaining precise light distribution control through the geometric design of the free-form surfaces

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system changes the fundamental parameter of light interaction from absorption to refraction. By using refractive free-form surfaces, the system achieves precise light distribution control through parameter optimization of surface geometry rather than through absorptive material properties, thereby maintaining high power transmission

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

This approach significantly reduces blurring effects, improving image sharpness by at least 20%, 40%, or 60%, and enables the creation of high-resolution, high-contrast light patterns with increased luminous flux and power efficiency, overcoming the limitations of conventional systems.

Implementation Method 1

with refractive optical free-form surfaces... The first and the second refractive optical freeform surface bring about Köhler illumination of a projection optics

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

the projection optics bring about Köhler illumination... which result in the image to be projected in an image surface of the projection optics

Methodology Applied
Scientific EffectOptical imaging: Lens

Data Source

PatentEP3345049B1Projection device
Publication Date: 2021.10.06 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP3345049B1 patent drawingFigure 1
  • EP3345049B1 patent drawingFigure 2
  • EP3345049B1 patent drawingFigure 3A~3C

AI summary

The invention relates to a projection device (2) comprising at least one light source (4) and an array of optical channels (6, 6a, 6b). Each channel comprises a first refractive optical free-form surface (8a, 8b) and a second refractive optical free-form surface (10a, 10b) and a projection optical system (12). The first and the second refractive optical free-form surfaces (8, 10) are arranged between the light source (4) and the projection optical system (12) and bring about a Köhler illumination of the projection optical system (12) from a light object structure (13a, 13b, 13a', 13b', 13a", 13b"), which produce the image (14a, 14b) to be projected on an image surface of the projection optical system (12), wherein the images of the array of optical channels (6) overlap.