Thin Lightguide With Micro-Optic Relief For Uniform Illumination
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Solution Overview
Problem
Conventional lightguides for keypad and keyboard lighting face challenges in achieving uniform illumination due to apertures needed for electrical contact, which also make them thicker and prone to defects, and roll-to-roll embossing methods result in artifacts in micro-optic surface relief structures due to material deformation.
Innovation Solution
A thin, flexible lightguide with micro-optic surface relief forms is used, integrated with a dome sheet and actuation members to provide tactile feedback and protect the dome sheet, while a stiffer layer is added for improved embossing results, allowing for roll-to-roll embossing without apertures and reducing artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If apertures are added to the lightguide for electrical contact, then electrical functionality is enabled, but illumination uniformity deteriorates and thickness increases
Solution Approach 1:
A separate dome sheet with conductive domes is introduced as an intermediary component between the lightguide and the key switches. This mediator provides the electrical contact function through the domes while keeping the lightguide itself continuous and aperture-free, thus preserving illumination uniformity.
Solution Approach 2:
The electrical contact function is segmented from the lightguide structure and placed in a separate dome sheet. This allows the lightguide to remain continuous for optimal light transmission while the domes provide discrete electrical contact points.
2Adaptability or versatility
If apertures are added to the lightguide for electrical contact, then electrical functionality is enabled, but manufacturing precision deteriorates due to defects
Solution Approach 1:
The dome sheet acts as an intermediary that carries the electrical contact function, eliminating the need for apertures in the lightguide. This separation prevents manufacturing defects associated with aperture creation while maintaining electrical functionality through the dome structures.
3Productivity
If roll-to-roll embossing is used to create micro-optic surface relief structures, then manufacturing efficiency is improved, but manufacturing precision deteriorates due to material deformation artifacts
Solution Approach 1:
A composite structure consisting of a support layer and a lightguide layer is used. The support layer provides mechanical stability during embossing, preventing deformation of the lightguide material. This composite approach enables high-speed roll-to-roll embossing while maintaining precise micro-optic surface relief structures without artifacts.
Solution Approach 2:
The support layer is placed beforehand to cushion and prevent material deformation during the embossing process. This pre-positioned support structure compensates for the softness of the lightguide material, ensuring accurate replication of micro-optic features.
4Length of stationary object
If the lightguide is made thinner to reduce overall thickness, then device compactness is improved, but structural strength deteriorates
Solution Approach 1:
The lightguide is constructed as a composite of a thin lightguide layer on top of a thicker support layer. The lightguide layer can be made very thin for compactness while the support layer provides the necessary structural strength and mechanical stability.
Solution Approach 2:
The lightguide uses a thin-film structure that is flexible and can be made extremely thin while still functioning. The support layer compensates for the reduced thickness, providing the structural integrity that a standalone thin film would lack.
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 solution enables efficient, uniform illumination with improved tactile feedback and reduced thickness, enhancing optical efficiency and manufacturing precision, allowing for cost-effective and flexible illumination solutions.
Implementation Method 1
The lightguides can be used for display lighting (e.g. backlighting, frontlighting), keypad, keyboard and/or button lighting, interior lighting, and exterior lighting, among other applications. Conventional lightguides that are considered as thin may have a thickness of about 0.8 to about 1.0 mm and include micro-optical structures.
Implementation Method 2
Such microstructures are often on the order of about 15 microns in height or more, and on the order of about 50 microns or more in one lateral dimension.
Data Source
AI summary
A lightguide arrangement including a substantially thin, lightguide for transporting and coupling light. At least one light source is coupled to the lightguide. A plurality of micro-optic surface relief forms are arranged on the lightguide. The lightguide is configured to produce one or more active indicative and/or decorative illumination effects via interaction between the one or more light sources and the plurality of micro-optic surface relief forms. A keypad assembly including the lightguide and uses of lightguide constructions.