Light Diffusion Film with Micro-Concave Holes for LED Glare Reduction

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Solution Overview

Problem

Conventional light diffusion films used in liquid crystal displays with LED light sources suffer from 'LED glare' due to the formation of bright points caused by convex lens-like structures, which can lead to insufficient viewing angles and poor luminous intensity distribution characteristics.

Innovation Solution

A light diffusion film with a specific irregular three-dimensional surface shape, characterized by an average roughness curve element length (RSm) of 70 µm or less, and a controlled inclination angle distribution, is developed to diffuse light effectively and reduce glare while maintaining the optical characteristics of the conventional product.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a light diffusion film with convex lens-like structures is used, then light diffusion is achieved, but LED glare occurs due to formation of bright points

Engineering Contradiction:

Improvelight diffusion capabilityVSAvoidLED glare

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The invention changes the geometric parameters of the surface structures from convex lens-like shapes to micro-concave holes, transforming the optical behavior from light focusing to light scattering. This parameter change eliminates the formation of bright points while maintaining effective light diffusion.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Instead of using convex structures that converge light, the invention inverts the approach by using concave hole structures that diverge and scatter light. This inversion of the geometric form fundamentally changes the optical interaction to prevent glare while achieving diffusion.

Inventive Principle:

Principle #13The other way round (Inversion)

2Ease of manufacture

If conventional diffusion structures are used, then light diffusion is achieved, but viewing angle is insufficient

Engineering Contradiction:

Improvediffusion functionVSAvoidviewing angle

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The invention optimizes the parameters of the micro-concave hole structures, including their size, depth, and distribution density, to control light scattering patterns. By adjusting these parameters, the film achieves both effective diffusion and expanded viewing angles.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite structure combining the transparent base film material with embedded micro-concave hole patterns. This composite design integrates the structural function of light scattering with the optical transparency of the base material, achieving both diffusion and wide viewing angles.

Inventive Principle:

Principle #40Composite materials

3Use of energy by moving object

If LED light sources are used instead of CCFLs, then power consumption is reduced, but LED glare problem occurs due to point light source characteristics

Engineering Contradiction:

Improvepower consumptionVSAvoidLED glare

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The invention converts the harmful effect of LED point light sources that cause glare into a benefit by designing micro-concave hole structures specifically tailored to scatter point source light effectively. The structure transforms the concentrated light into a diffused pattern, turning the glare problem into an opportunity for optimized light distribution.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 significantly reduces glare and maintains the luminous intensity distribution characteristics of the conventional product, ensuring a wider viewing angle and high total light transmittance, even when used with LED light sources.

Implementation Method 1

an irregular three-dimensional surface shape for diffusing light due to refraction

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentEP2772776B1Light diffusion film

Publication Date: 2018.05.02 MITSUBISHI GAS CHEM CO INC

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AI summary

The present invention is made to solve glare of an embossed matte film of a conventional product produced and sold by the applicant of the present application, and provides a light diffusion film and the like having a surface shape of an irregular pattern that significantly suppresses the glare even when an LED light source is used and also maintains the good optical characteristics. The present inventors analyzed the mechanism for solving the glare problem while maintaining good optical characteristics of the embossed matte film of the conventional product produced and sold by the applicant of the present application, and conceived the following as sufficient conditions for maintaining good optical characteristics of an embossed matte film and also for solving the glare. In order to maintain the optical characteristics, the surface shape was defined by use of an inclination angle histogram profile of an embossed surface. In order to solve the glare, the size of unit patterns which make up an entire pattern and do not cause glare was defined by use of the value of the average length RSm of the roughness curve element of the embossed surface.