Microplate Reader Filter Wheel Energy Balancing
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Solution Overview
Problem
In spectrophotometric optical systems of microplate readers, energy differences between light of various wavelengths cause mismatched analog signals, leading to detection accuracy issues and uneven light spots, which existing solutions like cold mirrors, attenuators, energy-matching filters, and diaphragms with center apertures either increase costs, complexity, or result in inadequate light distribution.
Innovation Solution
A filter wheel with a rotatable wheel body featuring narrow-band filters of different central wavelengths, where the narrow-band filter with a longer central wavelength is equipped with a diaphragm having a plurality of apertures, ensuring an energy balance between wavelengths and reducing vignetting for an even light spot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the gain value of the analog channel is increased to match the analog signal with the ADC range, then the signal matching is improved, but the noise in the circuit increases and detection accuracy degrades
Solution Approach 1:
The patent applies preliminary action by adjusting the energy amounts of lights of different wavelengths before they reach the detection circuit. By using optical filters and attenuators to pre-balance the energy distribution across wavelengths, the system ensures that the analog signals from different wavelength channels are already within the appropriate range for the ADC, eliminating the need to increase gain values and thus avoiding the generation of excess circuit noise
2Measurement precision
If energy amounts of lights of various wavelengths are balanced by adjusting light energy, then detection accuracy is improved, but the system complexity and manufacturing cost increase due to additional optical elements
Solution Approach 1:
The patent merges the energy balancing function into the existing optical filter components. By integrating attenuators with the optical filters or using the filters themselves to perform both wavelength selection and energy balancing, the system achieves energy balance without adding separate, complex optical elements for each function, thus reducing overall system complexity
Solution Approach 2:
The optical filters in the system are designed to serve multiple functions: wavelength selection and energy balancing. By making the filters universal components that perform both tasks, the patent eliminates the need for separate dedicated energy adjustment elements, thereby reducing device complexity while maintaining detection accuracy
3Measurement precision
If a cold mirror is positioned at 45 degrees to turn the light path, then energy balance can be achieved, but the space requirement increases and manufacturing cost rises
Solution Approach 1:
The patent extracts the energy balancing function from the cold mirror configuration and implements it directly within the optical filter assembly. By removing the need for separate 45-degree positioned cold mirrors and their associated space requirements, the system achieves energy balance through the filter components themselves, thereby reducing the overall space requirement in the optical path
4Measurement precision
If an attenuator is disposed in front of the optical filter, then energy balance is achieved, but the manufacturing cost notably increases
Solution Approach 1:
The patent merges the attenuator with the optical filter into a single integrated component. By combining these two elements that were previously separate (and thus required separate manufacturing and assembly processes), the system achieves energy balance without the additional manufacturing cost of separate attenuators, while maintaining the same optical performance
5Measurement precision
If a diaphragm with center aperture is used, then energy balance can be achieved, but the light spot becomes uneven and rim energy is low
Solution Approach 1:
The patent applies local quality by using optical filters with specific spectral transmission characteristics that are optimized for each wavelength channel. Instead of using a uniform diaphragm aperture that creates uneven illumination, the system employs filters with locally optimized transmission properties that balance energy across wavelengths while maintaining uniform light spot distribution, thereby achieving both energy balance and illumination uniformity
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 effectively balances energy between different wavelengths, reduces noise, and ensures an even light distribution across the microplate reader's channels, improving detection accuracy and manufacturing simplicity while minimizing costs.
Implementation Method 1
at least one narrow-band filter with a relatively long central wavelength mounted to the wheel body and at least one narrow-band filter with a relatively short central wavelength mounted to the wheel body
Implementation Method 2
the narrow-band filter with a relatively long central wavelength is provided with a diaphragm on a front surface thereof facing a lens of the system, the diaphragm being formed with a plurality of apertures
Implementation Method 3
an analog signal obtained by a photoelectric conversion should be ensured to match a range of an analog-to-digital converter (ADC) of a detection circuit
Data Source
AI summary
A spectrophotometric optical system of a microplate reader and a filter wheel thereof are disclosed. The filter wheel comprises a pivotable wheel body, at least one narrow-band filter with a relatively long central wavelength mounted to the wheel body, and at least one narrow-band filter with a relatively short central wavelength mounted to the wheel body. The narrow-band filter with a relatively long central wavelength is provided with a diaphragm on a front surface thereof The diaphragm is formed with a plurality of apertures. By the diaphragm attached to the front surface of the narrow-band filter with a relatively long central wavelength, an energy matching between light of longer wavelength and light of shorter wavelength may be achieved. Further, due to the uniformly distributed apertures in the diaphragm, an even light spot may be obtained.