Silicone Lens Array Mounting on PCB

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Solution Overview

Problem

The use of rigid materials like PMMA and polycarbonate for secondary lenses in LED luminaires limits the operating temperature due to thermal degradation, and silicone lenses, while more temperature-resistant, are difficult to mount precisely on printed circuit boards (PCBs) due to their softness, requiring new alignment and attachment methods.

Innovation Solution

A lens holder system that provides precise alignment and attachment of a moulded silicone secondary lens array to a PCB, using locating means such as apertures and clips to maintain alignment in the x-y plane and perpendicular direction, allowing for thermal expansion without optical distortion, and eliminating the need for tools or adhesives.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If rigid materials like PMMA or polycarbonate are used for secondary lenses, then precise positioning and mounting are achieved, but the operating temperature is limited due to thermal degradation

Engineering Contradiction:

Improvepositioning precisionVSAvoidoperating temperature

Core Design Contradiction:

Manufacturing precisionVSTemperature

Solution Approach 1:

The patent changes the material parameter from rigid plastics (PMMA, polycarbonate) to silicone elastomer, which has superior thermal stability. This material substitution allows the lens to withstand higher operating temperatures without degradation while maintaining optical functionality.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses silicone elastomer as a composite material that combines flexibility with thermal resistance. This material enables both high-temperature operation and adaptable mounting solutions that accommodate thermal expansion differences between components.

Inventive Principle:

Principle #40Composite materials

2Temperature

If silicone is used as a single moulded lens array, then higher operating temperatures are achieved, but precise alignment and mounting become difficult due to softness and flexibility

Engineering Contradiction:

Improveoperating temperatureVSAvoidalignment precision

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

The patent segments the mounting system into two functional parts: the silicone lens array itself and a separate rigid mounting structure (lens holder). This segmentation allows the lens to maintain its thermal advantages while the rigid holder provides precise positioning and alignment capabilities.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a rigid mounting structure as an intermediary between the flexible silicone lens array and the PCB. This intermediary component transfers the precision positioning requirement from the soft lens material to the rigid mounting structure, enabling both high-temperature operation and precise alignment.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If conventional mounting techniques like screws or rivets are used, then precise positioning is achieved, but the soft silicone material cannot be effectively mounted and alignment is lost

Engineering Contradiction:

Improvepositioning precisionVSAvoidmounting feasibility

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

Instead of trying to rigidly fix the soft silicone lens with conventional fasteners, the patent inverts the approach: the rigid mounting structure accommodates the flexible lens through elastic deformation. The lens holder is designed to flexibly retain the lens while maintaining precise positioning, reversing the traditional rigid-fastener paradigm.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent utilizes the flexible nature of the silicone lens by designing a mounting structure that accommodates this flexibility. The lens holder allows the soft lens material to elastically deform during mounting while maintaining precise alignment, rather than trying to rigidly constrain it.

Inventive Principle:

Principle #30Flexible shells and thin films

4Temperature

If heat dissipation structures like heat sinks are added, then operating temperature limits are maintained, but the amount of metal and cost increase

Engineering Contradiction:

Improvetemperature controlVSAvoidmetal usage

Core Design Contradiction:

TemperatureVSWeight of stationary object

Solution Approach 1:

The patent changes the thermal parameter of the lens material from temperature-sensitive rigid plastics to thermally stable silicone elastomer. This material parameter change eliminates the need for additional heat dissipation structures, allowing the system to operate at higher temperatures without increasing metal content or cost.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10197242B2Lens arrays and mountings

Publication Date: 2019.02.05 SCHREDER SA

AI summary

A light-emitting diode module includes a printed circuit board with a light-emitting diode array mounted on first surface. A secondary lens array is positioned over the light-emitting diode array and includes a secondary lens element for each light-emitting diode element in the light-emitting diode array. A lens holder is mounted to the printed circuit board and configured to retain each secondary lens element of the secondary lens array in alignment in an x-y plane with respect to each light-emitting diode element of the light-emitting diode array. The printed circuit board further includes a first locating feature corresponding to a second locating feature of either the secondary lens array or the lens holder. The locating features align the secondary lens array with respect to the light-emitting diode array on the printed circuit board.