Side-edge Light Guide with Single-Face Prism Lower Sheet

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Solution Overview

Problem

The existing side-edge type surface light emitting apparatus faces challenges with manufacturing complexity due to an air gap layer between the lower prism sheet and the light absorbing sheet, leading to potential contamination and fine defects, which degrade the privacy effect and increase manufacturing costs.

Innovation Solution

A side-edge type surface light emitting apparatus design featuring a single-face prism lower prism sheet with a flat outer surface, eliminating the air gap layer and reducing the risk of contamination, while maintaining the privacy effect by optimizing the angle and structure of the triangular prisms and light distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an air gap layer is provided between the lower prism sheet and the light absorbing sheet to secure total reflection, then the privacy effect is improved, but the manufacturing complexity increases and the risk of contamination and fine defects increases

Engineering Contradiction:

Improveprivacy effectVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the air gap layer from the structure, replacing it with direct contact between the lower prism sheet and light absorbing sheet. This removes the source of manufacturing complexity and contamination risk while maintaining the privacy effect through optimized prism design

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention merges the lower prism sheet and light absorbing sheet into direct contact, eliminating the intermediate air gap layer. This consolidation simplifies the structure and reduces manufacturing steps while achieving the same optical function through prism optimization

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If an air gap layer is provided between the lower prism sheet and the light absorbing sheet, then the total reflection is secured, but the risk of contamination and fine defects increases

Engineering Contradiction:

Improvetotal reflectionVSAvoidcontamination and fine defects

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The air gap layer is extracted and removed from the structure, eliminating the space where contamination can occur. The lower prism sheet and light absorbing sheet are brought into direct contact, removing the harmful factor of contamination risk while maintaining optical performance

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention converts the potential harm of direct contact (which might seem to reduce total reflection) into a benefit by optimizing the prism geometry and material properties, achieving both direct contact and effective total reflection, thereby eliminating contamination risk

Inventive Principle:

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

3Reliability

If the lower prism sheet has a non-flat outer surface to optimize light distribution, then the privacy effect is improved, but the handling and manufacturing difficulty increases

Engineering Contradiction:

Improveprivacy effectVSAvoidhandling and manufacturing

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention applies local quality by providing prism structures only on the inner surface of the lower prism sheet that contacts the light guide plate, while keeping the outer surface flat. This localized optical structure maintains privacy effect while ensuring ease of handling and manufacturing

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention segments the functional requirements by separating the optical function (prism structures) from the structural function (flat outer surface). The prism structures are confined to the inner surface for light distribution, while the outer surface remains flat for easy handling and manufacturing

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 design simplifies manufacturing, reduces defects, and maintains the privacy effect by ensuring easy handling and effective light distribution, thereby enhancing the overall performance and reducing costs.

Implementation Method 1

the light L21 of the light L2, which has a relatively small incident angle to the flat light incident surface 42 of the lower prism sheet 4, is totally reflected by the straight-sloped surfaces 41-1 and 41-2 of the triangular prisms 41 and returns to the light guide plate 1

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentUS11762240B2Side-edge type surface light emitting apparatus having light guide plate sandwiched by upper and lower prism sheets

Publication Date: 2023.09.19 STANLEY ELECTRIC CO LTD

AI summary

A side-edge type surface light emitting apparatus includes: a light guide plate having a first light emitting surface, a light distribution controlling surface, and a light incident surface; a light source; an upper prism sheet disposed on the upper side of the light guide plate, the upper prism sheet having multiple first prisms on a lower side and a second light emitting surface on an upper side; and a first lower prism sheet disposed on the lower side of the light guide plate, the first lower prism sheet having multiple second prims on an upper side and a first flat surface on a lower side.