Linear Variable Bandpass Filter Array with Cam Tilting
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Solution Overview
Problem
In scientific research and microscopy applications, there is a need for a compact and efficient optical filtering system that can quickly adjust and switch between different bandpass filters, especially in limited spaces, to accommodate various illumination and emission wavelengths, while maintaining precise control over the bandpass characteristics.
Innovation Solution
A linear array of variable bandpass filters with a tilting mechanism, utilizing a stationary cam or rail system, allows for precise adjustment of filter angles between 0 and 60 degrees, enabling rapid selection and switching of bandpass characteristics using a linear stepper motor and cam followers or pins, ensuring compactness and high-speed operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional filter wheels are used to switch between different bandpass filters, then wavelength selection is achieved, but the device size becomes large and space-consuming
Solution Approach 1:
The filter system is segmented into multiple individual filters arranged in a linear array, each capable of being independently positioned in the light path. This replaces the traditional single-wheel design with distributed filter elements, reducing the overall volume while maintaining wavelength selection capability.
Solution Approach 2:
The filters are arranged in a linear array along the optical axis (adding a dimensional aspect), allowing selective positioning of individual filters into the light path. This linear arrangement reduces the rotational space requirement of traditional filter wheels while achieving the same spectral selection function.
2Ease of operation
If the infinity space in microscopes is extended to accommodate filters, then filter placement is easier, but the collimation of light deteriorates
Solution Approach 1:
The filter positioning system is made dynamic, allowing filters to be moved along the optical axis to precisely control their position relative to the collimated light beam. This dynamic adjustment enables optimal filter placement that maintains collimation while providing ease of operation.
Solution Approach 2:
The system allows adjustment of the filter position parameter along the optical axis, enabling optimization of both collimation and ease of filter placement. By changing the positional parameter, the system maintains light quality while improving operational convenience.
3Productivity
If filter switching speed is increased for rapid wavelength changes, then experimental efficiency improves, but positioning precision may deteriorate
Solution Approach 1:
The mechanical filter switching system is replaced with a piezoelectric actuator-based positioning system. The piezoelectric elements provide rapid response times for high-speed switching while maintaining precise positioning control, resolving the trade-off between speed and accuracy.
Solution Approach 2:
The system incorporates feedback control for filter positioning, where the actual position of each filter is monitored and adjusted to achieve the desired wavelength selection. This feedback mechanism ensures positioning precision is maintained even during rapid switching operations.
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 solution enables precise and rapid adjustment of bandpass filters, allowing for efficient experimentation with minimal effort, covering the entire visible light spectrum and accommodating both filtered and unfiltered light conditions, with filters capable of tilting up to 60 degrees to accommodate a circular light beam, enhancing experimental flexibility and speed.
Implementation Method 1
The use of interference gratings that allow only transmission of a very narrow band of light wavelengths is a well known method of filtering light. Such filters may be referred to as bandpass filters.
Implementation Method 2
It is known that the range of bandpass frequencies of an optical interference filter shifts as a function of the angle of incidence of the light directed onto the filter. Recently, interference filters have been developed taking advantage of this property over a broad range of angles without substantial loss of the desired bandpass properties.
Data Source
AI summary
An optical system and method for illuminating an object under investigation with filtered light is disclosed. In one embodiment, the system comprises a linear filter array having a plurality of elongate variable bandpass filters. The variable bandpass filters each have a cam follower and are translatable along a longitudinal axis, whereby translation brings a selected filter in line with a beam of light. The cam follower of selected filter engages a cam adjacent to the array. This causes tilting of the filter to a desired angle thereby allowing precise selection of the bandpass frequency of the selected filter. Preferably, the filter can be tilted by an angle of up to 60°. Each elongate filter is preferably substantially rectangular and has a long dimension that is at least about twice the short dimension.