Planar Light Source With Layered Light Adjustment for Uniform Emission

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Solution Overview

Problem

Existing planar light sources exhibit luminance non-uniformity in the emission face due to localized high luminance near light emitting elements.

Innovation Solution

A planar light source design incorporating a light guide member with a light source, a first and second light adjusting member, and a first light transmissive member, where the second light adjusting member has higher light transmissivity than the first, arranged to distribute light uniformly across the emission face.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If light emitting elements are arranged directly under the light guide member plate, then light output is simplified and manufacturing is easier, but luminance becomes locally high near the light emitting elements causing non-uniformity

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidluminance uniformity
Core Design Contradiction:
Ease of manufactureVSIllumination intensity

Solution Approach 1:

A light scattering layer is introduced as an intermediary between the light emitting elements and the light guide member plate. This layer scatters the light emitted by the LEDs before it enters the light guide, distributing the light more uniformly across the plate surface and preventing localized high luminance regions while maintaining the simple direct arrangement of components.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The light scattering layer is positioned specifically in the region where light emitting elements are arranged, creating localized light scattering only where needed. This allows the light guide member plate to maintain its full light guiding capability in other regions while the scattering layer addresses the luminance non-uniformity issue at the light source locations.

Inventive Principle:
Principle #3Local quality

2Illumination intensity

If light scattering layer is added to reduce luminance non-uniformity, then luminance uniformity improves, but device complexity increases

Engineering Contradiction:
Improveluminance uniformityVSAvoidstructure complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The light scattering layer is implemented as a thin film or layered structure that can be easily integrated into the existing light guide assembly. This thin film approach provides effective light scattering to improve luminance uniformity while adding minimal structural complexity and maintaining a compact device profile.

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

The design reduces luminance non-uniformity by moderating the luminance directly above the light source, ensuring a more even distribution of light across the emission face.

Implementation Method 1

The first light adjusting member has a light reflectivity and a light transmissivity with respect to light emitted by the light source

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

The first light adjusting member has a light reflectivity and a light transmissivity with respect to light emitted by the light source

Methodology Applied
Scientific EffectLight transmission: Refraction

Implementation Method 3

The second light adjusting member has a light reflectivity and a light transmissivity with respect to light emitted by the light source

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 4

The second light adjusting member has a light reflectivity and a light transmissivity with respect to light emitted by the light source

Methodology Applied
Scientific EffectLight transmission: Refraction

Implementation Method 5

The first light transmissive member has a higher light transmissivity with respect to the light emitted by the light source than the light transmissivity of the first light adjusting member and the light transmissivity of the second light adjusting member

Methodology Applied
Scientific EffectLight transmission: Refraction

Data Source

PatentEP3859205B1Planar light source
Publication Date: 2025.10.08 NICHIA CORP
  • EP3859205B1 patent drawingFigure 1
  • EP3859205B1 patent drawingFigure 2
  • EP3859205B1 patent drawingFigure 3A~3B

AI summary

A planar light source includes a light guide member having a through hole, a light source, a first light adjusting member, a second light adjusting member, and a light transmissive member. The first light adjusting member having reflectivity and transmissivity with respect to light from the light source is disposed on or above an upper face of the light source in the through hole. The second light adjusting member having reflectivity and transmissivity with respect to the light from the light source is disposed above and apart from the first light adjusting member. The first light transmissive member having a higher transmissivity with respect to the light from the light source than the transmissivities of the first and second light adjusting members is disposed between the first light adjusting member and the second light adjusting member, and between a lateral face of the light source and the light guide member.