Spring Member Deflection for Compact Illumination Device

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Solution Overview

Problem

Existing illumination devices, such as vehicle headlights, face challenges in downsizing and weight reduction while maintaining optical stability under vibration and heat conditions, particularly due to the cantilever beam structure of plate springs which require fixing and increase the overall size of the structure.

Innovation Solution

The illumination device incorporates a spring member with a deflected center portion that generates spring force to hold the second optical element against a holder, eliminating the need for fixed ends and allowing for a more compact design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If plate springs with cantilever beam structure are used to hold optical elements, then the optical elements can be secured against vibration and heat, but the structure size increases due to the need for fixed ends

Engineering Contradiction:

Improveoptical stabilityVSAvoidstructure size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

Instead of fixing one end of the plate spring to the holder and letting the other end float (cantilever structure), the patent inverts the approach by making both ends of the plate spring free and allowing them to deflect. The optical element is positioned between two plate springs, and both springs deflect their center portions to press against the optical element, eliminating the need for fixed ends and reducing structure size while maintaining securing capability.

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If plate springs are fixed to the holder with set screws, then the optical elements can be held securely, but the device complexity and assembly difficulty increase

Engineering Contradiction:

Improveholding capabilityVSAvoidfixing structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the set screw fixing mechanism from the holder structure. Instead of fixing the plate springs to the holder with set screws, the plate springs are designed to be freely mounted on the holder with both ends capable of deflection. This removes the complexity of fixing structures while maintaining the holding capability through the elastic deflection of the plate springs themselves.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If conventional mounting structures are used for optical elements, then the optical elements can be held firmly, but weight reduction and downsizing become difficult

Engineering Contradiction:

Improvemounting stabilityVSAvoiddevice weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent employs thin plate spring structures that function as flexible mounting elements. These plate springs are made from thin elastic plates that can deflect and provide mounting stability without adding significant weight. The flexible nature of these thin film-like structures allows them to absorb vibration and heat effects while maintaining a lightweight profile, enabling both firm holding and weight reduction.

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 enables the downsizing of illumination devices by eliminating the need for fixed ends and reducing the overall size, while maintaining optical stability and withstanding vibration and heat conditions.

Implementation Method 1

a spring member including at least one spring portion that generates a spring force by being deflected, the spring member pressing the second optical element against the holder with the spring force

Methodology Applied

Scientific EffectSpring force: Spring

Implementation Method 2

the first optical element and the second optical element deflect a center portion in a long edge direction of the at least one spring portion with respect to ends in the long edge direction of the at least one spring portion

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS10564381B2Illumination device

Publication Date: 2020.02.18 MITSUBISHI ELECTRIC CORP

AI summary

An illumination device including: a light source including a light emitting element that emits light; a first optical element that transmits the light; a second optical element that transmits the light transmitted by the first optical element; a holder that holds the second optical element; and a spring member including at least one spring portion that generates spring force by being deflected, the spring member pressing the second optical element against the holder with the spring force to hold the second optical element against the holder, wherein the first optical element and the second optical element deflect a center portion in a long edge direction of the at least one spring portion with respect to ends in the long edge direction of the at least one spring portion.