Spectrophotometer Ambient Light Offset Compensation
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Solution Overview
Problem
Spectrophotometric measurements are challenged by ambient light interference, which complicates the detection of light absorbed or reflected by samples due to the need for complex and expensive electronics to differentiate between the spectrophotometer's light source and ambient light, and assumes stable ambient conditions during measurements.
Innovation Solution
An analog offset generator is used to compensate for ambient light, reducing the signal amplitude analyzed by the spectrophotometer's components, allowing for simpler and less expensive electronics, and enabling precise measurements without a light-tight lid or multiple measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple measurements are performed to compensate for ambient light, then measurement precision can be improved, but measurement time increases significantly
Solution Approach 1:
The patent applies preliminary action by performing an ambient light measurement before the actual spectrophotometric measurement. The control unit stores the ambient light value and subtracts it from the total light measurement, eliminating the need for multiple sequential measurements and significantly reducing measurement time while maintaining precision.
2Object-affected harmful factors
If the spectrophotometer's light source power is reduced, then ambient light interference becomes more significant, but sample damage is minimized
Solution Approach 1:
The patent uses feedback by measuring the ambient light level and using this information to compensate for its effect on the total measurement. The control unit subtracts the stored ambient light value from the total light measurement, allowing the use of lower light source power without compromising measurement precision, thus minimizing sample damage.
3Measurement precision
If a light-tight lid is used to block ambient light, then measurement accuracy is improved, but device complexity and ease of operation deteriorate
Solution Approach 1:
The patent replaces the mechanical solution of a light-tight lid with an electronic/software-based solution. The control unit performs digital subtraction of ambient light values from total light measurements, eliminating the need for physical light blocking mechanisms and simplifying the device structure and operation.
4Measurement precision
If electronic circuits with high precision are used to detect small light differences, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex high-precision electronic detection circuits with a simpler electronic system combined with digital signal processing. The control unit performs software-based subtraction of ambient light from total light measurements, achieving high detection precision without requiring expensive, complex electronic circuitry.
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 approach enables precise and reliable spectrophotometric measurements in the presence of strong ambient light, improving precision and reducing the complexity of electronic circuits, while maintaining accuracy even with changing ambient conditions.
Implementation Method 1
a light sensor for measuring the light emitted by the light source and passing through or reflected by a sample
Implementation Method 2
an analog offset generator for applying an offset value to an output of the light sensor
Data Source
AI summary
The present invention relates to a spectrophotometer comprising a light source; and a light sensor for measuring the light emitted by the light source and passing through or reflected a sample; and being characterized by an offset generator for applying an offset value to an output of the light sensor. The invention further relates to a method for performing a related spectrophotometric measurement.