Freeform Surface Illumination Design for Multiple Light Sources

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Solution Overview

Problem

Conventional illumination systems with freeform surfaces are designed for a single immovable light source and lose effectiveness when the light source is moved or multiple light sources are introduced, resulting in a decreased illumination effect.

Innovation Solution

A method for designing an illumination system with freeform surface that involves establishing an initial system with collimated light sources and a plane lens, replacing the plane lens with a sphere lens, selecting feature rays, and iteratively constructing freeform surfaces to achieve the desired light spot distribution, allowing for multiple light sources and maintaining illumination effectiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single immovable light source is used in the illumination system with freeform surface, then the illumination effect is optimized for that specific configuration, but the system loses effectiveness when the light source is moved or multiple light sources are introduced

Engineering Contradiction:

Improveadaptability to light source movement and multiple light sourcesVSAvoidillumination effect consistency

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The freeform surface is designed to serve multiple functions: it can handle both single and multiple light sources, accommodate light source movement, and maintain consistent illumination effects across different configurations. The iterative design process creates a universal optical element that adapts to various operational scenarios without requiring system redesign.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The illumination system incorporates dynamic adaptability through the freeform surface design that can compensate for light source movement. The iterative optimization process creates surface geometries that maintain performance across different light source positions, effectively making the system adaptable to dynamic conditions rather than fixed configurations.

Inventive Principle:

Principle #15Dynamics

2Measurement precision

If conventional rotational symmetric surfaces are used, then the system structure is simpler, but the light path control accuracy is reduced compared to freeform surfaces

Engineering Contradiction:

Improvelight path control accuracyVSAvoidsurface geometry complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs asymmetric freeform surfaces that break the conventional rotational symmetry to achieve superior light path control. The iterative design process optimizes these asymmetric geometries to precisely direct light rays, demonstrating that the increased geometric complexity translates directly into improved optical performance and control accuracy.

Inventive Principle:

Principle #4Asymmetry

3Area of stationary object

If multiple light sources are introduced to the illumination system, then the illumination coverage is improved, but the illumination effect decreases with conventional freeform surface designs

Engineering Contradiction:

Improveillumination coverage areaVSAvoidillumination effect quality

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The patent addresses multiple light sources by segmenting the optical design approach - the freeform surface is iteratively optimized to handle individual light source contributions separately while integrating them into a unified illumination pattern. This segmentation strategy allows each light source to be accounted for individually, maintaining high illumination quality across extended coverage areas.

Inventive Principle:

Principle #1Segmentation

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 method ensures that light spots maintain consistent parameters and distribution even when light sources are moved, achieving improved illumination efficiency and stability through multiple construction iterations, with an average RMS deviation reducing from 10.94 μm to 3.98 μm after 2000 iterations.

Implementation Method 1

a freeform surface has larger degrees of freedom, which can accurately control light path

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS10816794B2Method for designing illumination system with freeform surface

Publication Date: 2020.10.27 HON HAI PRECISION INDUSTRY CO LTD

AI summary

A method for designing illumination system with freeform surface, the method comprising: presupposing a plurality of expected light spots; establishing an initial system, wherein the initial system comprises a plurality of collimated light sources, a plane lens and a target plane; designing a sphere lens to replace the plane lens, and obtaining a before-construction-iteration illumination system; selecting a plurality of feature rays and obtaining a plurality of target points; taking the before-construction-iteration illumination system as an initial construction-iteration system, and obtaining an after-construction-iteration illumination system with freeform surface by making multiple construction-iteration, wherein the illumination system with freeform surface is configured to form the plurality of expected light spots.