Vehicle Lamp Light-Guide Fixation Structure Against Point Illumination

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Solution Overview

Problem

Existing light-guiding body fixation structures in vehicle lamps face issues with point illumination and inadequate fixation against vehicle vibrations, particularly when using screw fixation or groove insertion methods.

Innovation Solution

A light-guiding body fixation structure where the light-guiding body has protrusions on opposite sides that fit into recesses in the housing, combined with a cylinder and base plate arrangement that secures the body without screws, restricting movement in multiple directions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If screw fixation is used to fix the extension portion, then fixation strength is improved, but point illumination occurs causing harmful light leakage

Engineering Contradiction:
Improvefixation strengthVSAvoidpoint illumination
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The invention extracts the harmful extension portion that causes point illumination by eliminating the need for extension portions entirely. Instead, the light-guiding body is directly fixed to the housing through integrated positioning protrusions and recesses, removing the source of light leakage while maintaining fixation strength.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Rather than extending the light-guiding body outward and fixing it separately (which causes point illumination), the invention inverts the approach by having the housing directly engage with positioning protrusions on the light-guiding body. This reverses the fixation logic to eliminate harmful light leakage while maintaining strength.

Inventive Principle:
Principle #13The other way round (Inversion)

2Object-generated harmful factors

If the extension portion is inserted into the groove of the holding portion, then point illumination is prevented, but fixation reliability deteriorates under vehicle vibration

Engineering Contradiction:
Improvepoint illuminationVSAvoidfixation reliability
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The invention employs a composite fixation mechanism combining multiple elements: positioning protrusions for precise location, engagement protrusions with elastic deformation capability for secure holding, and claw portions for additional mechanical interlocking. This composite approach prevents point illumination while ensuring reliability under vibration.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The engagement protrusion is designed with elastic deformation capability, allowing it to dynamically adapt to assembly variations and maintain reliable fixation. The elastic portion can deform to accommodate tolerances while still providing secure engagement, preventing both point illumination and loosening under vibration.

Inventive Principle:
Principle #15Dynamics

3Strength

If the light-guiding body is fixed with screws, then fixation strength is improved, but device complexity increases

Engineering Contradiction:
Improvefixation strengthVSAvoidfixation structure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The invention merges multiple fixation functions into integrated structural features. The positioning protrusions, engagement protrusions, and claw portions are all part of the housing and light-guiding body structures themselves, eliminating the need for separate screws or fasteners while maintaining fixation strength and reducing complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The housing and light-guiding body are designed with self-fixing features where the structures themselves provide the fixation mechanism. The engagement protrusions and claw portions automatically engage during assembly without requiring additional fastening operations, making the system self-service and reducing complexity.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4257876B1Light-guiding body fixation structure and vehicle lamp
Publication Date: 2026.02.04 ICHIKOH IND LTD
  • EP4257876B1 patent drawingFigure 1
  • EP4257876B1 patent drawingFigure 2
  • EP4257876B1 patent drawingFigure 3

AI summary

To prevent point illumination and fix a light-guiding body. The present invention includes: a fixation portion having a first holding portion and a second holding portion; engagement portions that restrict frontward movement of the one end portion in the front-back direction; an elastic portion that generates elastic force upward in the up-down direction, and abuts on the one end portion to maintain engagement of the engagement portions; contact portions that bring the first holding portion and the one end portion into contact with each other on both sides in the left-right direction; an abutment portion that abuts on the one end portion to restrict backward movement of the one end portion in the front-back direction; and a restriction portion that abuts on the elastic portion to restrict downward movement of the elastic portion in the up-down direction.