Quartz Window Surface for Uniform UV-LED Light Extraction
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Solution Overview
Problem
Existing window materials for UV-LEDs face issues with durability, cost, and size due to the use of cylindrical lenses or crystalline fluororesin, leading to inefficient light collection and uneven light distribution.
Innovation Solution
A window material formed of synthetic quartz glass with a flat plate shape and a rough surface having specific surface properties, allowing efficient light collection and uniform light distribution without a lens shape, achieved through chemical etching and surface processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a cylindrical lens is used to control light distribution, then light uniformity is improved, but device size increases
Solution Approach 1:
The patent applies spherical curvature to the window material surface to achieve light collection and distribution uniformity. The convex spherical surface acts as a lens to focus and distribute light uniformly without requiring a cylindrical lens structure, thereby maintaining compact device size while achieving the desired light uniformity.
Solution Approach 2:
The patent changes the surface parameters of the window material by creating a rough surface with specific surface roughness (Ra: 0.01 μm to 10 μm) and spherical curvature. This parameter change enables the flat window material to collect and distribute light uniformly, replacing the need for larger cylindrical lens structures.
2Loss of energy
If synthetic quartz glass is processed into a lens shape to improve light extraction, then light extraction efficiency is improved, but manufacturing cost increases
Solution Approach 1:
The patent applies spherical curvature to the window material surface, which can be achieved through relatively simple processes like spin coating with spherical particles or surface treatment, rather than complex lens grinding and polishing. This maintains good light extraction efficiency while significantly reducing manufacturing complexity and cost.
Solution Approach 2:
The patent creates a rough surface structure on the window material that can be considered a form of controlled porosity or surface texture. This rough surface with spherical features enhances light extraction efficiency through increased light-matter interaction and scattering, while being manufacturable through cost-effective processes.
3Illumination intensity
If crystalline fluororesin is used for lens-shaped member to control light distribution, then light distribution is improved, but durability against UV light deteriorates
Solution Approach 1:
The patent changes the material from crystalline fluororesin to synthetic quartz glass, which has superior UV resistance and durability. The spherical surface parameters are then applied to this durable material to achieve the desired light distribution, thus maintaining reliability while achieving the optical function.
Solution Approach 2:
The patent uses synthetic quartz glass as the base material, which provides excellent UV resistance and durability. The spherical surface structure is then applied as a surface treatment or coating on this durable substrate, creating a composite structure that combines the durability of quartz glass with the light distribution capabilities of a lens-like surface.
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 compact and cost-effective light collection with uniform light distribution, reducing the size and cost of optical element packages and devices while maintaining high durability against UV light.
Implementation Method 1
a window material for an optical element package that houses an optical element emitting or receiving light... has a flat plate shape... includes main surfaces through which the light is transmitted, at least one of the main surfaces being a rough surface
Data Source
AI summary
The window material for an optical element of the present invention is formed of synthetic quartz glass that is likely to be subjected to shape processing, can be manufactured at low cost, and has a flat plate shape. Even if the window material for an optical element has a flat plate shape, for example, in a window material of a UV-LED such as a UVC-LED sealed with a surface mount package (SMD PKG), light emitted from the optical element, in particular, light having a light distribution angle can be efficiently collected when passing through the window material, and light collection equal to that of a window material having a lens shape such as a conventional convex shape can be achieved. Furthermore, light distribution without irradiation unevenness such as Lambertian reflection can also be achieved.