Midwest Optical Systems (MidOpt; Palatine, IL, USA) has developed a new line of neutral density filters for imaging at visible, near-infrared (NIR), and near-UV wavelengths (350-1100nm). These "NI" filters are available from stock in four optical densities that range from 50% to 6.25% overall transmission, in all popular filter thread sizes, ready for next-day delivery.
Neutral density filters are used to reduce the amount of light reaching the sensor. This allows for longer exposure times and reduced depth of field by using a wider iris opening, thus improving the separation of subject matter from the background.
Unlike absorptive filter glass and non-reflective neutral density filters, the low-reflectivity NI filters from MidOpt feature uniform attenuation simultaneously over the entire visible and near-IR range imaged by most industrial CCD/CMOS cameras, with the actual percent transmission (or optical density) remaining constant.
Uniform transmission over an extremely broad spectral range
These filters also feature a reflection-inhibiting vacuum-evaporated protective overcoat that is designed to reduce undesirable back reflections while maintaining uniform transmission over an extremely broad spectral range. Compared to absorptive neutral density filters, MidOpt's NI Filters use a low expansion glass substrate material to enhance durability and resistance to temperature extremes and thermal shock at no additional cost.
Optical densities in the new NI Filter line include NI030 (OD = 0.3, 50% transmission), NI060 (OD = 0.6, 25% transmission), NI090 (OD = 0.9, 12.5% transmission) and NI120 (OD = 1.2, 6.25% transmission).
NI Filters are available off-the-shelf in standard threaded mounts, in thicknesses of 1, 2 and 3mm, and in custom shapes and sizes. Typical custom applications include reducing transmission from broadband light sources, low power laser attenuation and partial shrouding of inspection applications. Lead times for custom manufactured components are approximately one week.
In the US, contact:
Midwest Optical Systems, Inc.
322 Woodwork Lane
Palatine, IL 60067 USA
Source: Midwest Optical Systems
-- Posted by Vision Systems Design
MidOpt unveils neutral density filters for VIS/NIR imaging
Midwest Optical Systems has developed a new line of neutral density filters for imaging at visible, near-infrared (NIR), and near-UV wavelengths (350-1100nm).