Colorimetric Device with Low Reflectance Unit
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Solution Overview
Problem
Conventional colorimetric devices face challenges in accurately measuring the two-dimensional color distribution of samples due to the limitations of integrating spheres, which are either too large and heavy for portable devices or suffer from incomplete specular component exclusion when trying to increase the measurement aperture size, leading to reduced measurement accuracy.
Innovation Solution
A compact colorimetric device design incorporating an integrating sphere with a first aperture for sample measurement and a second aperture for light reception, along with a low reflectance unit that reduces specularly reflected light, allowing for high-accuracy two-dimensional color measurement by minimizing the impact of specular reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the integrating sphere is made large to maintain measurement accuracy with adequate apertures, then measurement precision is improved, but device weight and size increase making it non-portable
Solution Approach 1:
The integrating sphere is divided into two separate components: a compact illumination sphere containing only the light source and diffusing surface, and a separate detection system with imaging optics. This segmentation allows the illumination sphere to be made very small (portable) while the detection system handles the aperture and imaging functions, resolving the contradiction between size and measurement capability
Solution Approach 2:
A beam splitter is introduced as an intermediary optical element that separates the illumination path and detection path. This allows the compact integrating sphere to illuminate the sample while the reflected light is directed to separate imaging optics, enabling portable device design without sacrificing measurement precision
2Area of stationary object
If the measurement aperture diameter is increased to measure larger sample areas, then measurement area increases, but specular reflected light enters the light receiving aperture reducing measurement accuracy
Solution Approach 1:
The illumination and detection functions are spatially separated using a beam splitter. The light receiving aperture is positioned at a location where specular reflected light from the sample does not directly enter, while still allowing diffuse reflected light to be captured by the imaging optics. This geometric separation resolves the contradiction between measurement area and measurement accuracy
Solution Approach 2:
The specular component of reflected light is extracted and excluded from the detection path through careful optical design. The light receiving aperture is positioned to receive only diffuse reflected light, while specular reflections are directed away from the aperture, eliminating the harmful effect on measurement precision
3Adaptability or versatility
If multiple large apertures are provided in the integrating sphere for measurement and light reception, then measurement capability is improved, but the integrating sphere function for diffuse illumination is reduced
Solution Approach 1:
The illumination and detection functions are separated into different optical paths using a beam splitter. This allows the integrating sphere to maintain its diffuse illumination function with minimal apertures while the detection system provides versatile measurement capability through imaging optics, resolving the contradiction between adaptability and reliability
Solution Approach 2:
The separate detection system with imaging optics provides multi-functional measurement capability (different fields of view, measurement modes) without requiring multiple large apertures in the integrating sphere. The single aperture configuration maintains diffuse illumination while the versatile detection system achieves adaptability through optical design
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 device achieves high-accuracy color measurement on the surface of samples by effectively reducing the impact of specular reflections, maintaining the compactness and portability of the device while improving measurement precision.
Implementation Method 1
illumines, using an integrating sphere, a sample disposed at an aperture portion of the integrating sphere as a target of colorimetry, receives reflected light from the sample
Implementation Method 2
to reduce an error in colorimetry caused by specularly reflected light that can be produced by a gloss on the surface, the sample is measured under specular component excluded (SCE) conditions
Data Source
AI summary
A colorimeter includes an integrating sphere, a light source, a light receiver and a low reflectance unit. The integrating sphere has a first aperture to be covered with a sample and a second aperture opposing the first aperture configured to allow reflected light from the sample to pass therethrough. The light source irradiates an inner wall of the integrating sphere with light. The light receiver receives, through the second aperture, the reflected light from a surface of the sample that enters the integrating sphere through the first aperture when the light from the light source is reflected by the inner wall, and is applied to the sample through the first aperture, and outputs a signal in accordance with the reflected light. The low reflectance unit is disposed around the light receiver to face an internal space of the integrating sphere, and has lower light reflectance than the inner wall.