Light Source Lens Mounting With Radial Thermal Expansion Clearance

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Solution Overview

Problem

Existing light source units face issues with lens displacement and deformation due to thermal expansion and contraction, affecting illuminance and illumination range, particularly when used in varying temperature environments.

Innovation Solution

A light source device with a metal substrate, plastic lens, and metal fasteners, featuring elongated holes in the lens that extend radially with a width increasing portion, allowing the lens to thermally expand and contract without significant displacement or interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the lens is fixed with a mounting screw through an elongated hole, then the lens can be securely mounted, but the lens is prone to displacement when it thermally expands in high-temperature environments

Engineering Contradiction:
Improvemounting securityVSAvoidlens position stability
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The elongated hole is designed to allow the lens to move dynamically with thermal expansion. The hole's length and orientation enable the lens to shift position as it expands or contracts, preventing displacement while maintaining secure mounting through the fastening structure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The geometry of the elongated hole is specifically designed with certain length and orientation parameters that accommodate thermal expansion. By changing the hole's dimensional parameters, the structure adapts to temperature variations while maintaining mounting security.

Inventive Principle:
Principle #35Parameter changes

2Strength

If the lens is fixed with a mounting screw through an elongated hole, then the lens can be securely mounted, but the lens may be deformed when it thermally contracts in low-temperature environments

Engineering Contradiction:
Improvemounting securityVSAvoidlens shape integrity
Core Design Contradiction:
StrengthVSShape

Solution Approach 1:

The elongated hole allows the lens to contract dynamically without being constrained by the mounting structure. The hole's geometry provides clearance that prevents the mounting screw from interfering with the lens during thermal contraction, avoiding deformation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The design anticipates thermal contraction and pre-provides sufficient clearance in the elongated hole to prevent the mounting structure from constraining the lens. This preliminary design consideration eliminates the harmful effect of deformation before it can occur.

Inventive Principle:
Principle #9Preliminary anti-action

3Stability of the object's composition

If the lens is securely fastened to prevent displacement, then mounting stability is improved, but the lens cannot thermally expand or contract freely

Engineering Contradiction:
Improvelens mounting stabilityVSAvoidthermal expansion capability
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The elongated hole creates a dynamic mounting system where the lens can move within the hole's boundaries. This dynamic design allows thermal expansion and contraction while the fastening structure maintains overall mounting stability through the elongated geometry.

Inventive Principle:
Principle #15Dynamics

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 maintains consistent alignment and functionality of the lens with the fasteners, ensuring stable illuminance and illumination range despite temperature changes.

Implementation Method 1

The lens expands or contracts due to various factors. For example, lenses expand or contract in response to temperature changes. Specifically, when the light source unit is used in a high-temperature environment or when the light source generates heat, the lens thermally expands.

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

Conversely, when the light source unit is used in a low-temperature environment, the lens thermally contracts.

Methodology Applied
Scientific EffectThermal contraction: Thermal Contraction

Data Source

PatentEP4589194A1Light source device
Publication Date: 2025.07.23 TOYOTA INDUSTRIES CORP
  • EP4589194A1 patent drawingFigure 1
  • EP4589194A1 patent drawingFigure 2
  • EP4589194A1 patent drawingFigure 3

AI summary

A light source device includes a metal substrate, a light source fixed to the substrate, and a plastic lens fixed to the substrate with a metal fastener. The lens is provided with an elongated hole through which the fastener is inserted. The elongated hole extends in a radial pattern centered on a specified positioning point defined in the lens. The elongated hole includes a width increasing portion in which a width of the elongated hole increases as a distance from the positioning point increases.