Projection Lens Holder Layout for Thermal Focus Compensation

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Solution Overview

Problem

Thermal expansion of lenses in lighting devices causes defocusing, leading to compromised image quality, and existing solutions either use heavy and expensive glass lenses or impose unpredictable deformation with support elements.

Innovation Solution

A light module design with a fixed base, first and second support elements having different thermal expansion coefficients, allowing the projection optics to deform and compensate for focal plane displacement by opposing movements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If glass lenses are used to prevent thermal expansion, then thermal stability is improved, but weight and manufacturing cost increase

Engineering Contradiction:

Improvethermal stabilityVSAvoidlens weight

Core Design Contradiction:

Stability of the object's compositionVSWeight of moving object

Solution Approach 1:

The patent replaces expensive glass lenses with plastic lenses that can be easily replaced. The projection optic is designed as a removable module that can be swapped out, making the system more cost-effective while maintaining functionality despite thermal expansion effects

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent uses a composite structure combining plastic projection optics with a thermally stable support element. This allows the optical element to be made of inexpensive plastic while the mounting structure provides thermal stability, resolving the contradiction between material cost and thermal performance

Inventive Principle:

Principle #40Composite materials

2Stability of the object's composition

If glass lenses are used to prevent thermal expansion, then thermal stability is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvethermal stabilityVSAvoidmanufacturing complexity

Core Design Contradiction:

Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent adopts plastic projection optics that are easier and less expensive to manufacture than glass lenses. The simplified material allows for more straightforward manufacturing processes while the modular design enables easy replacement if needed

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent divides the projection optic into separate replaceable modules. This segmentation allows the optical element to be manufactured independently using simpler plastic materials, reducing overall manufacturing complexity while maintaining system functionality

Inventive Principle:

Principle #1Segmentation

3Stability of the object's composition

If the lens is clamped by a support element, then thermal expansion is constrained, but optical surface deformation increases

Engineering Contradiction:

Improvedimensional stabilityVSAvoidoptical surface precision

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent applies different support characteristics to different regions of the projection optic. The support element provides stabilization at the mounting perimeter while deliberately leaving the central optical surface area free from constraints, allowing optimal optical performance in the critical region

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Instead of clamping the lens to prevent expansion, the patent inverts the approach by providing minimal support at the edges and allowing the optical surface to remain unconstrained. This reversal prioritizes optical quality over complete dimensional restraint

Inventive Principle:

Principle #13The other way round (Inversion)

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

Maintains the focal plane close to its initial position despite temperature changes, ensuring sharp image projection without the need for expensive materials.

Implementation Method 1

the first support element has a first coefficient of thermal expansion, while the second support element has a second coefficient of thermal expansion that differs from the first

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

the second support element is arranged to allow thermal expansion of the projection optics causing displacement of the focal plane

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP4370375B1Motor vehicle light module comprising a member for holding the projection lens

Publication Date: 2026.04.01 VALEO VISION SA

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Figure 3~4
Figure 5A~5B

AI summary

The invention relates to a light module (1) comprising: - a fixed base (7) intended to act as a support for a light source (2); - a projection lens (3) having a focal plane (F) and arranged to project a light beam from the light rays emitted by the light source (2); and - a holding member (4) for holding the projection lens (3). According to the invention, the holding member (4) comprises a first support element (41) and a second support element (42). The second support element (42) acts as a support for the projection lens. The first support element (41) connects the second support element to the fixed base. The support elements (41, 42) are arranged so as to position the focal plane (F) at a location where the light module ensures good quality of the projection image despite the heat expansion of the projection lens.