Light Collection Lens Segmentation for Fluorescent Member Uniformity

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Solution Overview

Problem

Conventional light projection devices with fluorescent members illuminated by laser light suffer from excessive light density issues, leading to degradation due to heat and chemical reactions, and non-uniform light intensity distributions, which are exacerbated by vibrations or aging of components.

Innovation Solution

A light projection unit with a light collection member that changes the direction of laser light and guides it to a smaller emission surface, positioned a predetermined distance away from the fluorescent member's application surface, ensuring uniform light intensity distribution and reducing excessive light density, while a reflective member controls the fluorescent light emission for efficient illumination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a light collection lens is used to collect laser light and apply it to a fluorescent member, then light collection efficiency is improved, but excessive light density is concentrated at the light collection point causing degradation of the fluorescent member

Engineering Contradiction:
Improvelight collection efficiencyVSAvoidexcessive light density causing degradation
Core Design Contradiction:
Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The light collection lens is divided into multiple light collection regions (first, second, third light collection regions) that correspond to different emission regions of the fluorescent member. This segmentation distributes the laser light across multiple areas rather than concentrating it at a single point, reducing light density at any one location while maintaining overall collection efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the light collection lens are assigned different functions: the first light collection region collects light for the first emission region, the second light collection region (with different refractive index) collects light for the second emission region, and the third light collection region collects light for the third emission region. This local differentiation optimizes light distribution and prevents excessive concentration in any single area.

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If the application surface of the fluorescent member is displaced from the light collection point, then direct contact with the highest intensity point is avoided, but the light intensity distribution remains non-uniform due to Gaussian distribution

Engineering Contradiction:
Improvedegradation from direct contact with high intensity pointVSAvoidnon-uniform light intensity distribution
Core Design Contradiction:
Object-affected harmful factorsVSIllumination intensity

Solution Approach 1:

The fluorescent member is divided into multiple emission regions (first, second, third emission regions) that correspond to different light collection regions. This ensures that laser light is distributed across multiple areas of the fluorescent member rather than concentrated at a single point, achieving uniform light intensity distribution while avoiding degradation.

Inventive Principle:
Principle #1Segmentation

3Reliability

If vibration or aging causes displacement of components, then alignment is disturbed, but the segmented light collection design maintains uniform light distribution

Engineering Contradiction:
Improvestability against vibration and agingVSAvoidlight distribution uniformity
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The light collection lens and fluorescent member are both divided into multiple corresponding regions. This segmentation creates a distributed system where misalignment due to vibration or aging affects multiple regions simultaneously rather than concentrating error at a single point, maintaining relatively uniform light distribution and improving reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The second light collection region is designed with a different refractive index from the first and third regions. This parameter change provides tolerance against misalignment by allowing light to be collected and distributed effectively even when component positions shift slightly due to vibration or aging.

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 configuration reduces the production of high light density areas on the fluorescent member, minimizes degradation, and enhances light utilization efficiency by maintaining uniform light distribution and effective control of light emission, even with component displacements.

Implementation Method 1

a fluorescent member that includes an application surface to which the laser light emitted from the light collection member is applied, that converts at least a part of the laser light into fluorescent light and that mainly emits the fluorescent light from the application surface

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Data Source

PatentEP2518838B1Light projection unit and light projection device
Publication Date: 2019.03.13 SHARP KK
  • EP2518838B1 patent drawingFigure 1~2
  • EP2518838B1 patent drawingFigure 3
  • EP2518838B1 patent drawingFigure 4

AI summary

A light projection unit (20) is provided that can reduce the production of a portion where the light density is excessively increased on a fluorescent member (22). This light projection unit includes: a light collection member (21) that includes a light entrance surface (21a) and a light emission surface (21b) which has an area smaller than that of the light entrance surface; a fluorescent member (22) that includes an application surface (22a) to which the laser light emitted from the light collection member is applied and that mainly emits fluorescent light from the application surface; and a light projection member (23) that projects the fluorescent light. The light emission surface (21b) of the light collection member is arranged a predetermined distance from the application surface (22a) of the fluorescent member (22).