Lightguide Protective Layer Reducing Flaw Glowing
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Solution Overview
Problem
Existing display devices using lightguide plates with prisms suffer from flaws or dirt causing unwanted glowing of areas other than the intended pattern, as light is scattered or reflected out of the plate, making these imperfections visible to the viewer.
Innovation Solution
A display device with a lightguide plate and a transparent protective layer having a smaller refractive index than the plate, which covers the emission surface and includes a diffusion layer to diffuse light, preventing light from reaching flaws or dirt and reducing unwanted glowing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a lightguide plate with prisms is used to display patterns, then the pattern visibility is improved, but flaws or dirt on the surface cause unwanted glowing that reduces display quality
Solution Approach 1:
A protective layer with a lower refractive index than the lightguide plate is introduced as an intermediary between the lightguide plate and the external environment. This protective layer prevents light from escaping at the emission surface, thereby eliminating unwanted glowing from flaws or dirt while preserving the prism-based pattern display functionality.
Solution Approach 2:
The refractive index parameter of the protective layer is specifically chosen to be lower than that of the lightguide plate. This parameter change creates the necessary condition for total internal reflection at the protective layer-lightguide plate interface, preventing light leakage and unwanted glowing while maintaining pattern visibility.
2Use of energy by moving object
If light propagates within the lightguide plate through total reflection, then light efficiency is improved, but any flaw or dirt on the surface scatters or reflects light out of the plate causing unwanted glowing
Solution Approach 1:
The protective layer serves as a mediator that maintains total internal reflection conditions at the emission surface. By having a lower refractive index than the lightguide plate, it ensures that light propagating within the plate remains confined and does not scatter out through surface flaws or dirt, thus preserving light efficiency while eliminating harmful scattering.
3Manufacturing precision
If a protective layer with smaller refractive index is added to reduce unwanted glowing, then display clarity is improved, but device complexity increases
Solution Approach 1:
The protective layer is implemented as a thin film structure that covers the emission surface of the lightguide plate. This thin film approach maintains display clarity by preventing light leakage while minimizing the increase in device complexity through its simple, lightweight construction.
Solution Approach 2:
The display device becomes a composite structure combining the lightguide plate material with the protective layer material. This composite approach achieves the desired display clarity by leveraging the refractive index difference between materials while keeping the overall structure relatively simple through material composition rather than mechanical complexity.
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 effectively reduces the visibility of flaws or dirt while enhancing the viewable range of the intended pattern by ensuring light is totally reflected within the lightguide plate, preventing it from escaping through imperfections and improving the clarity of the displayed pattern.
Implementation Method 1
a transparent protective layer covering at least a part of the emission surface, the protective layer having a smaller refractive index than the lightguide plate
Implementation Method 2
The diffusion layer may diffuse light emitted through the emission surface
Implementation Method 3
a plurality of prisms on a surface of the lightguide plate, the plurality of prisms being arranged along the at least one pattern to reflect light emitted from the light source and entering the lightguide plate through the incident surface out of the lightguide plate through an emission surface
Data Source
AI summary
A display device according to one or more embodiments may include a lightguide plate comprising a transparent part, and an incident surface, the lightguide plate configured to display at least one pattern; and a light source facing the incident surface. The lightguide plate may include a plurality of prisms on a surface of the lightguide plate, the plurality of prisms being arranged along the at least one pattern to reflect light emitted from the light source and entering the lightguide plate through the incident surface out of the lightguide plate through an emission surface of the lightguide plate, and a transparent protective layer covering at least a part of the emission surface, the protective layer having a smaller refractive index than the lightguide plate.