Lighting Device With Curved Phosphor Layer for Uniform Luminance

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Solution Overview

Problem

Conventional lighting devices using surface light sources experience dark lines due to significant distance differences between the upper and side surfaces, leading to non-uniform luminance.

Innovation Solution

The lighting device features a phosphor layer with a curved surface design, reducing the distance variations between the side surface and the light source, thereby preventing dark lines and enhancing luminance uniformity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If a polyhedron structure with bent upper surface and side surface is used, then the lamp can achieve a three-dimensional effect and unique aesthetic sense, but dark lines are generated on the edge region due to considerable distance between the upper surface and side surface from the light emitting device

Engineering Contradiction:
Improvethree-dimensional effectVSAvoiddark lines on edge region
Core Design Contradiction:
ShapeVSIllumination intensity

Solution Approach 1:

The patent applies curvature to the side surface of the phosphor layer, transforming it from a flat or bent surface to a curved surface. This curved configuration reduces the distance variation between the light emitting device and different regions of the phosphor layer, thereby eliminating dark lines on the edge region while preserving the three-dimensional aesthetic effect.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Adaptability or versatility

If the distance between the upper surface and side surface is considerably far from the light emitting device, then the lamp structure can be designed with more freedom, but the time for light to arrive is increased, resulting in non-uniform luminance

Engineering Contradiction:
Improvedesign freedomVSAvoidluminance uniformity
Core Design Contradiction:
Adaptability or versatilityVSIllumination intensity

Solution Approach 1:

The patent applies different surface characteristics to different regions of the phosphor layer. The curved side surface is specifically designed to reduce distance variation in the edge region, while the overall structure maintains design freedom. This localized optimization ensures uniform luminance without compromising the overall design versatility.

Inventive Principle:
Principle #3Local quality

3Illumination intensity

If a flat upper surface and curved side surface configuration is used, then the lamp can achieve uniform luminance, but the manufacturing complexity increases

Engineering Contradiction:
Improveluminance uniformityVSAvoidmanufacturing complexity
Core Design Contradiction:
Illumination intensityVSEase of manufacture

Solution Approach 1:

The curved side surface of the phosphor layer is designed to work in conjunction with the flat upper surface to achieve uniform luminance. This curvature configuration is integrated into the molding process, allowing the complex geometry to be manufactured efficiently using existing injection molding techniques without significantly increasing manufacturing complexity.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 curved phosphor layer design effectively prevents dark lines and improves luminance uniformity across the surface light source.

Implementation Method 1

a phosphor layer disposed on the resin layer

Methodology Applied
Scientific EffectPhosphorescence: Phosphorescence

Data Source

PatentEP4254525B1Lighting device
Publication Date: 2025.10.01 LG INNOTEK CO LTD
  • EP4254525B1 patent drawingFigure 1~2
  • EP4254525B1 patent drawingFigure 3~4
  • EP4254525B1 patent drawingFigure 5~6

AI summary

The lighting device disclosed in the embodiment includes a substrate, light sources disposed on the substrate at predetermined intervals, a resin layer disposed on the substrate and the light sources, and a phosphor layer disposed on the resin layer. The phosphor layer includes a first region overlapped with some of the N light sources in a direction perpendicular to the substrate and including a flat region, and a second region extending from a side surface of the first region toward the substrate and including a curved surface. The second region includes a first point horizontally in contact with the substrate from a center of a first light source closest to the side surface of the resin layer, a second point on the curved surface, and a third point where a straight line perpendicular to the substrate passes the center of the first light source, and a second distance from the center of the first light source to the second point is greater than a first distance from the center of the first light source to the first point, and is smaller than a third distance from the center of the first light source to the third point.