Planar Illumination Apparatus FPC Groove Integration

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Solution Overview

Problem

Existing planar illumination apparatuses face issues with light leakage and uneven brightness due to gaps between the flexible printed circuit board (FPC) and reflective sheet, and the formation of thin portions in reflective sheets leads to decreased reflectivity and alignment accuracy, increasing production complexity and costs.

Innovation Solution

A planar illumination apparatus configuration where the FPC is disposed on the same plane as the reflective sheet, with a thin portion extending from the mounting portion and overlapping with the reflective sheet, eliminating gaps and maintaining high reflectivity without additional production steps or materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If the FPC and reflective sheet are disposed facing each other to reduce thickness, then the thickness of the illumination apparatus is reduced, but gaps are generated causing light leakage and uneven brightness

Engineering Contradiction:

Improvethickness of illumination apparatusVSAvoidlight leakage prevention

Core Design Contradiction:

Length of stationary objectVSReliability

Solution Approach 1:

The FPC is inserted into a groove formed in the reflective sheet, creating a nested structure where the FPC is housed within the reflective sheet's groove. This nesting arrangement eliminates gaps between the FPC and reflective sheet while maintaining a compact thickness, preventing light leakage without requiring additional bonding layers.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The FPC is designed with flexible characteristics allowing it to conform to the groove structure of the reflective sheet. The flexible nature of the FPC enables it to be inserted and secured within the groove, ensuring intimate contact and eliminating gaps that would cause light leakage.

Inventive Principle:

Principle #30Flexible shells and thin films

2Length of stationary object

If a thin portion is formed in the reflective sheet to accommodate the FPC, then the thickness is reduced, but the reflectivity decreases

Engineering Contradiction:

Improvethickness of reflective sheetVSAvoidreflectivity of reflective sheet

Core Design Contradiction:

Length of stationary objectVSIllumination intensity

Solution Approach 1:

Instead of forming a thin portion in the reflective sheet, the invention creates a groove structure that maintains the full thickness and reflectivity of the reflective sheet in the illumination path. The groove is a localized structural feature that accommodates the FPC without compromising the overall reflectivity of the reflective sheet.

Inventive Principle:

Principle #3Local quality

3Reliability

If the FPC is laminated on the reflective sheet to eliminate gaps, then light leakage is prevented, but the thickness increases

Engineering Contradiction:

Improvegap eliminationVSAvoidthickness of illumination apparatus

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

Inventive Principle:

Principle #7Nested doll (Nesting)

4Adaptability or versatility

If additional production steps are taken to form thin portions in the reflective sheet, then the FPC can be accommodated, but the manufacturing complexity and costs increase

Engineering Contradiction:

ImproveFPC accommodationVSAvoidproduction process complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The reflective sheet is segmented to include a groove structure that accommodates the FPC. This segmentation is integrated into the reflective sheet's manufacturing process, allowing the groove to be formed as part of the reflective sheet production without requiring separate additional steps for thin portion formation.

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

This configuration reduces the thickness of the illumination apparatus without light leakage, maintains high reflectivity, and improves alignment accuracy, enabling cost-effective and efficient production.

Implementation Method 1

a reflective sheet (107) disposed on the back surface 216b side of the light guide plate 216

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS8651721B2Planar illumination apparatus

Publication Date: 2014.02.18 MINEBEAMITSUMI INC

AI summary

A planar illumination apparatus includes: a light source; a light guide plate having a light-receiving end surface arranged facing the light source, an output flat surface for planarly outputting light received through the light-receiving end surface and a reflective flat surface facing the output flat surface; a reflective sheet disposed on the reflective flat surface side of the light guide plate; and a flexible printed circuit board disposed on substantially the same plane as that of the reflective sheet, the flexible printed board mounting the light source, wherein the flexible printed circuit board has a mounting portion on which the light source is mounted and a thin portion which extends from a forward side edge and is formed thinner than the mounting portion, and wherein at least one part of the thin portion and an end portion of the reflective sheet are overlapped with each other.