Hemispherical Optical Integrator with Dual-Reflectance Plane
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Solution Overview
Problem
Conventional methods for measuring the total luminous flux of light sources, such as LEDs and ELs, face challenges due to light absorption errors from jigs and integrated circuits, and high costs associated with materials needed for high reflectance in the ultraviolet region for hemispherical optical integrators.
Innovation Solution
A hemispherical optical measurement apparatus with a plane portion composed of a metal-deposited mirror for specular reflection and sintered polytetrafluoroethylene or barium sulfate for diffuse reflection, optimizing the reflectance in the ultraviolet region to reduce absorption and enhance integrating efficiency while minimizing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plane mirror with high reflectance material is used for the entire surface, then integrating efficiency is improved, but cost increases
Solution Approach 1:
The plane portion is divided into an outer portion with specular reflection characteristics and an inner portion with diffuse reflection characteristics. The outer portion uses a reflection layer for high reflectance, while the inner portion uses a diffusing material. This local differentiation allows the system to achieve high integrating efficiency through the outer portion's specular reflection while reducing cost by using a cheaper diffusing material in the inner portion where specular reflection is less critical.
2Ease of manufacture
If a diffusing material is used for the plane portion, then cost is reduced, but integrating efficiency decreases
Solution Approach 1:
The plane portion is divided into an outer portion with specular reflection characteristics and an inner portion with diffuse reflection characteristics. The outer portion uses a reflection layer for high reflectance, while the inner portion uses a diffusing material. This local differentiation allows the system to achieve high integrating efficiency through the outer portion's specular reflection while reducing cost by using a cheaper diffusing material in the inner portion where specular reflection is less critical.
3Measurement precision
If correction for light absorption is applied, then measurement accuracy is improved, but it becomes insufficient for integrated light sources
Solution Approach 1:
The measurement system extracts and eliminates the light-absorbing components (mounting jig and lighting circuit) from the measurement space by positioning them outside the hemispherical integrating space. The light source is mounted on the plane portion with only the light-emitting portion exposed through a window, so that the jig and circuit do not absorb light within the integrating space. This extraction of harmful elements enables accurate measurement of integrated light sources without requiring complex correction calculations.
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 apparatus achieves higher integrating efficiency and reduced costs by minimizing light absorption and maintaining high reflectance in the ultraviolet region, allowing for precise measurement of total luminous flux and quantum efficiency with reduced errors.
Implementation Method 1
a hemispherical portion (1) having, on an inner surface, a diffuse reflection layer (1a)
Implementation Method 2
a plane mirror (10) that causes specular reflection (mirror reflection) of light
Implementation Method 3
an outer portion (12) formed of a material that causes mirror reflection (specular reflection) and occupying at least a region of a predetermined width from an outermost circumference
Implementation Method 4
an inner portion (14) formed of a material having a higher reflectance for at least an ultraviolet region than the material for the outer portion (12), and occupying a region inside the outer portion (12)
Data Source
AI summary
An optical measurement apparatus includes a hemispherical portion having a diffuse reflection layer on an inner wall, and a plane portion disposed to involve a substantial center of curvature of the hemispherical portion and close an opening of the hemispherical portion, and having a reflection layer on an inner surface side of the hemispherical portion. The plane portion includes: at least one of a window for introducing light to be homogenized in an integrating space formed between the hemispherical portion and the plane portion, and a window for extracting light homogenized in the integrating space; an outer portion formed of a first material chiefly causing specular reflection, and occupying at least a region of a predetermined width from an outermost circumference; and an inner portion formed of a second material chiefly causing diffuse reflection and having a higher reflectance for at least an ultraviolet region than the first material.