You can view the Filter Finder tool for either the interference filters or all other filters.
You can enter your ideal performance parameters in the zones and search the Comar filter database for the filter with the best fit. For each zone, please input a minimum and a maximum wavelength range, a desired transmission value, and an ideal tolerance.
A ‘zone’ is an area of the spectrum where you have a required transmission (or blocking level). You can define the bandwidth of the zone by entering lower λ and upper λ wavelength limits, and the desired transmission you would ideally like (normally 0% or 100%). If your requirement is just for transmission or blocking at a single wavelength, enter lower and upper wavelengths that just straddle the requirements (e.g. for high transmission at 632.8nm, enter 632 nm to 634 nm, Transmission 100 %).
The tolerance boxes provide a way of weighting the zone values in the selection process. A smaller tolerance will increase the importance of meeting the target in that zone. Typical values are 5% to 10% for values near 100%, and smaller near 0%. To demand a rejection of OD = -3, set a value of 0 and a tolerance of 0.1%.
The tolerances selected show in the zone bands as a darker area having a height of plus and minus the requested tolerance.
Please make sure that the zones do not overlap in wavelength and allow a minimum wavelength separation of 3nm. You do not have to specify all three zones. For example, you might want to specify just two zones for an edge filter.
When you search a coloured band appears in the graph for each zone.
If you select Find best single filter, the tool will search and offer you the single filter that best fits your requirements.
Selecting Search combinations of 2 filters requires the tool to calculate all possible combinations of any two filters in an attempt to meet your requirements. For example, the tool could select a combination of a long pass and a short pass filter to give a suitable band pass filter.
When you click on Search, the graph will display the best match or the best combination of filters. It will also display the merit values for each zone and a total merit value for all zones, which is a measure of how good the match is. If the merit function value is less than 1, then the filter or filter combination generally meets your requirements (based on an rms assessment).
The graph defaults to showing transmission in the y axis from 0 to 100% and wavelength range in the x axis according to the full width of the available data.
By selecting Scale to zones you can restrict the graph x axis to showing just the wavelength range for the selected zones.
The Log scale box, if ticked, changes the y axis to display optical density (OD) rather than percent transmission.
You can zoom in to any part of the graph by left-click selecting the area of interest. To reset the scale, double click in the graph area. (Note that tolerance shading will disappear if you zoom in, but the tolerance range is still valid for searching.)
If the first result is not quite perfect, then click on Try again to give you the next best fit results.
Data shown comes from scans of actual parts, and so is typical. There will be slight performance variations from batch to batch: if absolute blocking or transmission level is critical please check the specifications of the parts in question or contact us to verify this.
You can choose a filter by using the drop-down menu or simply enter the part number. Then click on the Search button to view the filter transmission curve.
