Light Converging Sheet Unit for LCD Backlight Newton-Ring Elimination

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Solution Overview

Problem

Conventional backlight modules for LCDs suffer from Newton-rings and rainbows due to optical interference, which degrade picture quality and increase production costs, especially when the upper diffusion sheet is removed.

Innovation Solution

A light converging sheet unit comprising first and second light converging sheets with micro-prism structures where the average peak-to-peak distance between adjacent micro-prism structures is not larger than 35 μm, reducing optical interference and eliminating the need for an upper diffusion sheet.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the upper diffusion sheet is removed to reduce production cost, then production cost is reduced, but Newton-rings become more easily observed and picture quality deteriorates

Engineering Contradiction:

Improveproduction costVSAvoidNewton-rings

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The invention changes the peak-to-peak distance parameter of the micro-prism structures from conventional larger values to specifically 35 μm or less. This parameter change modifies the optical interference conditions, preventing Newton-rings from forming even without the upper diffusion sheet, thus resolving the contradiction between cost reduction and picture quality maintenance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention converts the potentially harmful optical interference effects into beneficial light distribution patterns. By carefully designing the micro-prism structures with peak-to-peak distance of 35 μm or less, the optical interference that would normally create Newton-rings is transformed into effective light convergence and diffusion, eliminating the need for the upper diffusion sheet while maintaining or improving picture quality

Inventive Principle:

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

2Ease of manufacture

If conventional light converging sheets with larger peak-to-peak distance are used, then manufacturing is easier and cost is lower, but rainbows and Newton-rings are generated

Engineering Contradiction:

Improvemanufacturing easeVSAvoidrainbows

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The invention changes the critical parameter of peak-to-peak distance from conventional larger values to 35 μm or less. This parameter modification prevents the formation of rainbows by altering the light refraction and interference patterns, while the micro-prism structures remain manufacturable using standard processes

Inventive Principle:

Principle #35Parameter changes

3Illumination intensity

If multiple light converging sheets are stacked to converge light in multiple directions, then brightness is improved, but Newton-rings are generated due to optical interference

Engineering Contradiction:

ImprovebrightnessVSAvoidNewton-rings

Core Design Contradiction:

Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the peak-to-peak distance parameter to 35 μm or less in the light converging sheets. This parameter change prevents optical interference that causes Newton-rings, allowing multiple sheets to be stacked for brightness enhancement without generating harmful interference patterns

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses multiple light converging sheets with micro-prism structures segmented in different directions. Each sheet converges light in specific directions, and when stacked, they provide comprehensive light convergence in multiple directions while the controlled peak-to-peak distance prevents Newton-rings from forming

Inventive Principle:

Principle #1Segmentation

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 effectively prevents Newton-rings and maintains sufficient brightness for LCDs, reducing production costs by eliminating the need for additional optical sheets while maintaining picture quality.

Implementation Method 1

first and second light converging sheets that are stacked one on top of the other, that are disposed above the lower diffusion sheet, and that respectively have micro-prism structures... the first and second light converging sheets cooperate to converge light

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

Stacking of the first and second light converging sheets, and optical interference caused by optical sheets of the backlight modules result in Newton-rings

Methodology Applied

Scientific EffectInterference: Interference

Data Source

PatentUS7944614B2Light converging sheet unit

Publication Date: 2011.05.17 ZHEJIANG JINHUI OPTOELECTRONIC MATERIAL CO LTD

AI summary

A light converging sheet unit includes first and second light converging sheets stacked one on top of the other. The first light converging sheet has first light converging micro-prism structures with a first average peak-to-peak distance between adjacent ones of the first light converging micro-prism structures. The second light converging sheet has second light converging micro-prism structures with a second average peak-to-peak distance between adjacent ones of the second light converging micro-prism structures. At least one of the first and second average peak-to-peak distances is not larger than 35 μm.