Light Distribution Member Manufacturing with Ceramic Shielding

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Solution Overview

Problem

Existing light emitting devices with wavelength conversion members in automotive headlights face issues with light leakage between adjacent light emitting elements, and current methods for preventing this, such as using reflective resins or metal/dielectric films, are inefficient in terms of space and light shielding effectiveness.

Innovation Solution

A method involving a joined body of transmissive plates with a light shield part, a light-shielding frame made of reflective ceramic, and a reflective member to prevent light leakage between lit and unlit light emitting elements without reducing emission efficiency, where the light shield part includes a metal layer or dielectric multilayer film, and the light-shielding frame surrounds the outer periphery of the joined body.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a reflective resin containing titanium oxide is disposed between adjacent wavelength conversion members, then light leakage is prevented, but space is consumed and boundary darkness occurs

Engineering Contradiction:

Improvelight leakageVSAvoidspace between wavelength conversion members

Core Design Contradiction:

Object-affected harmful factorsVSVolume of stationary object

Solution Approach 1:

The patent applies a thin film light-shielding coating (5-50 μm thickness) on the side surface of the wavelength conversion member instead of using a bulk reflective resin layer. This thin film approach prevents light leakage while consuming minimal space and avoiding the boundary darkness problem caused by thick reflective resin layers.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent changes the thickness parameter of the light-shielding layer to an optimized range (5-50 μm) that is sufficient to prevent light leakage but thin enough to avoid causing boundary darkness when adjacent light emitting elements are activated simultaneously.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If a light-shielding film is formed on the side surface of a flat wavelength conversion member, then light shielding effect is improved, but manufacturing complexity increases due to bumpy surfaces and film thickness control difficulties

Engineering Contradiction:

Improvelight shielding effectVSAvoidfilm formation process

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent forms the wavelength conversion member with a curved outer peripheral surface instead of a flat surface. This curvature eliminates the bumpy surface problem that causes uneven film thickness, making the light-shielding film formation process simpler and more reliable while maintaining effective light shielding.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Productivity

If wavelength conversion members are arranged closely to improve emission efficiency, then light leakage between adjacent elements increases

Engineering Contradiction:

Improveemission efficiencyVSAvoidlight leakage between adjacent elements

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent uses a thin film light-shielding coating on the side surfaces of wavelength conversion members, allowing them to be arranged closely together without significant spacing while still preventing light leakage. This enables high emission efficiency to be maintained while avoiding the light leakage problem that would occur with close spacing.

Inventive Principle:

Principle #30Flexible shells and thin films

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 method effectively prevents light leakage between transmissive pieces of lit and unlit light emitting elements while maintaining high emission efficiency, allowing for precise manufacturing of light emitting devices with improved light distribution and reduced emission unevenness.

Implementation Method 1

a light-shielding frame provided so as to surround an outer periphery of the joined body as seen from one direction, the light-shielding frame being made of light reflective ceramic

Methodology Applied

Scientific EffectLight reflection: Reflection

Implementation Method 2

the light shield part including a layer composed of a metal, a multilayer film composed of metal, or a multilayer film composed of dielectric in which two or more types of dielectric are laminated

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentEP3093893B1Method for manufacturing light distribution members, method for manufacturing light emitting device, light distribution member, and light emitting devices

Publication Date: 2020.03.18 NICHIA CORP

Figure 1A~1C
Figure 1D~1E
Figure 1F~2B

AI summary

A method for manufacturing light distribution members (12) includes: preparing a joined body (18) in which a plurality of light transmissive plates (10a, possibly containing a phosphor) are joined with a light shield part (11) being interposed between adjacent ones of the light transmissive plates; fixing a light-shielding frame (19, possibly made of ceramic) to the joined body so as to surround an outer periphery of the joined body as seen from one direction; and cutting the joined body and the light-shielding frame perpendicularly to a surface of the joined body to which the light-shielding frame is fixed, thereby obtaining a plurality of light distribution members each having a plurality of light transmissive pieces (10). Light emitting devices, based on light emitting diodes/elements (13) or on a laser diode (13a), incorporating the resulting light distribution (and possibly wavelength conversion) member (12) are then disclosed.