Spectrophotometer Integrating Sphere Heterogeneous Sample Measurement
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Solution Overview
Problem
Conventional spectrophotometers are limited to measuring homogeneous liquid samples, as they cannot accurately account for light scattering in heterogeneous liquid or thin film samples, leading to incorrect light absorptivity measurements.
Innovation Solution
A spectrophotometer design that incorporates a single light source capable of emitting both excitation and measurement light, combined with an integrating sphere and a sample placement unit, allows for the measurement of light absorptivity in heterogeneous samples by accounting for forward scattered light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional spectrophotometer with orthogonal optical paths is used to measure homogeneous liquid samples, then measurement precision is maintained, but the device cannot accurately measure heterogeneous liquid or thin film samples due to light scattering
Solution Approach 1:
The patent merges the excitation light path and measurement light path into a single optical path through the sample. The light source emits light that passes through the sample, and the same optical path is used for both excitation and measurement, eliminating the need for separate orthogonal paths. This allows the detection unit to capture both transmitted and scattered light components, enabling accurate measurement of heterogeneous samples while maintaining measurement precision.
Solution Approach 2:
The patent introduces a integrating sphere to collect light in multiple directions (360 degrees) around the sample, transitioning from a single-direction detection approach to multi-directional detection. This dimensional change in light collection allows the system to capture forward-scattered light that would otherwise be missed, resolving the contradiction between measuring heterogeneous samples and maintaining measurement accuracy.
2Adaptability or versatility
If separate excitation light source and measurement light source are used with orthogonal optical paths, then measurement accuracy is maintained for homogeneous samples, but device complexity increases and heterogeneous samples cannot be measured
Solution Approach 1:
The patent employs a single light source that serves dual functions: it acts as both the excitation light source and the measurement light source. This light source emits light across a wavelength range that includes the excitation wavelength, allowing it to perform both photoreaction excitation and absorbance measurement functions. This multi-functionality eliminates the need for separate light sources and complex orthogonal optical paths, reducing device complexity while expanding sample type capability.
3Measurement precision
If only transmitted light is detected in conventional spectrophotometers, then measurement simplicity is maintained, but forward scattered light is lost leading to incorrect absorptivity for heterogeneous samples
Solution Approach 1:
The patent introduces an integrating sphere as an intermediary component between the sample and the detection unit. The integrating sphere collects light transmitted through the sample and redirects it toward the detection unit, ensuring that both directly transmitted light and forward-scattered light are captured. This intermediary device enables complete light collection without significantly complicating the overall detection system, resolving the contradiction between measurement precision and device 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
This design enables accurate measurement of the number of photons absorbed by heterogeneous liquid or thin film samples, overcoming the limitations of conventional spectrophotometers and expanding the range of measurable samples.
Implementation Method 1
a light source configured to emit light in a wavelength band including an excitation wavelength which causes a photoreaction on a target substance in a sample
Implementation Method 2
when a heterogeneous liquid sample such as a sol or a get or a thin film sample is irradiated with measurement light, a part of light passing through the sample is scattered (forward scattered)
Implementation Method 3
a light intensity measurement unit configured to measure intensity of light having the excitation wavelength emitted from the light emission port
Implementation Method 4
an excitation wavelength which causes a photoreaction on a target substance in a sample
Data Source
AI summary
A spectrophotometer includes: a light source configured to emit light in a wavelength band including an excitation wavelength which causes a photoreaction on a target substance in a sample, the light source emitting a known number of photons of the light having the excitation wavelength; an integrating sphere having a light entrance port through which light emitted from the light source enters and a light emission port provided at a position deviated from an optical axis of the light entering the light entrance port; a sample placement unit provided in the light entrance port; and a light intensity measurement unit configured to measure intensity of light having the excitation wavelength emitted from the light emission port.