Optical Member With Light Distribution Control for Forward Output

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Solution Overview

Problem

Conventional sheet-like illumination devices using LED elements are limited in application and suffer from low light utilization and diffusion, making them unsuitable for easy installation on windows or walls, and have issues with light transmission efficiency.

Innovation Solution

An optical member comprising a light guide member with a luminous intensity distribution control structure and cover members that allow over 50% of incident light to be output forward, with cover members having low reflectance and a controlled luminous intensity distribution to enhance directivity and light transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional sheet-like illumination devices are used, then light transmission is achieved, but light utilization factor is low and illumination light is diffused (large Haze value)

Engineering Contradiction:
Improvelight utilization factorVSAvoidillumination light quality
Core Design Contradiction:
Loss of energyVSIllumination intensity

Solution Approach 1:

The patent divides the light guide layer into multiple functional zones with different properties. The light guide layer includes a light receiving surface, a light output surface, and internal structures that segment and redirect light paths, allowing different portions of light to be directed forward while maintaining overall transmission efficiency and reducing diffusion.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by creating regions within the light guide layer with different optical properties. The cover members have specific reflectance characteristics (25% or lower) applied to specific surfaces, and the light guide layer has varying refractive indices or internal structures in different zones to control light direction locally, improving forward light output while maintaining overall system performance.

Inventive Principle:
Principle #3Local quality

2Illumination intensity

If reflection by cover member is used to improve output efficiency, then forward light output is improved, but light utilization factor transmitted through the device is lowered

Engineering Contradiction:
Improveforward light outputVSAvoidlight utilization factor
Core Design Contradiction:
Illumination intensityVSLoss of energy

Solution Approach 1:

The patent changes the reflectance parameter of the cover members to 25% or lower, which is a specific quantitative parameter change. This optimized reflectance value allows sufficient forward light output while minimizing the negative impact on overall light utilization, representing a precise parameter optimization to balance the two conflicting requirements.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If illumination device is designed for skylight application, then light transmission is achieved, but installation on window or wall is difficult

Engineering Contradiction:
Improveapplication scopeVSAvoidinstallation ease
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent designs the illumination device with universal applicability by creating a modular structure that can be installed in multiple locations including windows, walls, and skylights. The light guide layer and cover members are designed as interchangeable components that can adapt to different installation environments, making the device versatile for various architectural applications while maintaining ease of installation through standardized mounting interfaces.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution enables illumination devices suitable for various applications including windows and walls, with improved light utilization and reduced glare, enhancing their versatility and effectiveness.

Implementation Method 1

a light guide layer having a light receiving surface at which the light output from a light source is received

Methodology Applied
Scientific EffectLight transmission: Refraction

Implementation Method 2

a luminous intensity distribution control structure capable of directing, at least forward, a portion of the light propagated in the light guide layer

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 3

the first cover member and the second cover member each have a reflectance of 25% or lower for visible light incident perpendicularly thereon

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP4596955A1Optical member and illumination device
Publication Date: 2025.08.06 NITTO DENKO CORP
  • EP4596955A1 patent drawingFigure 1
  • EP4596955A1 patent drawingFigure 2
  • EP4596955A1 patent drawingFigure 3A~3C

AI summary

An optical member (100) comprises a light guide member (110) and at least one cover member (200F), (200R), and is configured so as to emit light towards the front surface side. The light guide member comprises: a light guide layer (10) having a light-receiving side surface that receives light emitted from a light source (LS); and a light distribution control structure (14A) that can guide at least a portion of the light propagated inside the light guide layer towards the front surface side. The at least one cover member includes: a first cover member (200F) disposed on the front surface side of the light guide member; or a second cover member (200R) disposed on the rear surface side opposite to the front surface side of the light guide member. The optical member is configured such that over 50% of the light that has entered the light guide layer is emitted from the front surface side of the light guide member.