Planar Illumination Device Pillar Groove Support

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Solution Overview

Problem

In enlarged planar illumination devices with a long light incident side, conventional elastic support structures fail to effectively prevent rattle noise due to increased clearance and the inversion of the aspect ratio of the elastic member, leading to instability and noise generation.

Innovation Solution

A planar illumination device design featuring a light guide plate with a groove at the center of the light incident side engaging with a protruding pillar from the bottom frame, combined with elastic members pressing the light guide plate from the non-light incident side, provides stable support by restricting movement and absorbing thermal expansion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the light guide plate is enlarged to increase horizontal length for on-board applications, then the illumination area is improved, but the clearance between the side wall of the bottom frame and the light guide plate increases, causing the elastic member to become unstable and pop out when compressed

Engineering Contradiction:

Improveillumination areaVSAvoidstability of elastic member

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The support structure is segmented into multiple functional elements: the elastic member for absorption, the pillar for positioning, and the groove for engagement. This segmentation allows each element to perform its specific function effectively, preventing the elastic member from popping out while maintaining support for the enlarged light guide plate

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The groove in the light guide plate is designed to engage with and contain the pillar from the bottom frame. This nesting structure ensures that the pillar remains positioned within the groove, providing stable support and preventing the elastic member from becoming unstable when compressed

Inventive Principle:

Principle #7Nested doll (Nesting)

2Reliability

If the elastic member is placed only on the side at the non-light incident side instead of at the corner portion, then the aspect ratio problem is avoided, but movement of the light guide plate in the long-side direction cannot be restricted, and rattle noise generation cannot be effectively prevented

Engineering Contradiction:

Improvestability of elastic memberVSAvoidrattle noise

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The solution merges multiple support mechanisms into a unified structure: the elastic member provides compression and absorption, while the pillar-groove engagement provides positioning and movement restriction. This combination allows the structure to maintain stability without rattle noise while supporting the enlarged light guide plate

Inventive Principle:

Principle #5Merging (Combining)

3Device complexity

If the light guide plate is simply placed without support structures, then the structure is simplified, but vibration causes the light guide plate to come into contact with the bottom frame, generating rattle noise

Engineering Contradiction:

Improvestructural complexityVSAvoidrattle noise

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The elastic member acts as a flexible element that absorbs vibration and thermal expansion while maintaining contact between the light guide plate and the bottom frame structure. This flexible support prevents the light guide plate from freely contacting the bottom frame during vibration, eliminating rattle noise while keeping the structure relatively simple

Inventive Principle:

Principle #30Flexible shells and thin films

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 effectively prevents rattle noise and ensures stable support of the light guide plate even in enlarged configurations, by utilizing the pillar to restrict longitudinal movement and the elastic members to absorb expansion and contraction, while maintaining optical efficiency.

Implementation Method 1

the elastic member presses and supports the light guide plate

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

components of the planar illumination device such as the light guide plate expand and contract according to a change in temperature

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

a groove configured to engage with the pillar

Methodology Applied

Scientific EffectMechanical engagement: Mechanical Fastener

Data Source

PatentUS11650366B2Planar illumination device including a pillar and an elastic member

Publication Date: 2023.05.16 MINEBEAMITSUMI INC

AI summary

A planar illumination device of an embodiment includes a light guide plate, a plurality of light sources, an elastic member, and a bottom frame. The light guide plate receives light from a light incident side surface. The plurality of light sources emit light to the light incident side surface of the light guide plate. The elastic member presses and supports the light guide plate. The bottom frame houses the light guide plate, the plurality of light sources, and the elastic member. The bottom frame includes a pillar configured to protrude in a thickness direction at a position opposing substantially a center of the light incident side surface of the light guide plate in a longitudinal direction. The light guide plate includes, substantially at the center of the light incident side surface in the longitudinal direction, a groove configured to engage with the pillar. The elastic member presses a side of the light guide plate at a non-light incident side toward a light incident side.