Scanning for Ideas: Filters adjust light intensity

Oct. 11, 2007
Engineers and optical technicians often need to adjust the intensity of lasers and lights, especially in imaging systems.

To simplify the task, engineers at Reynard Corp., San Clemente, Calif. (reynardcorp. com), designed a line of Circular Variable Neutral Density Filters. These round devices have a metallic coating that varies smoothly across the surface. Depending on where light is shining through, the filter changes its intensity from 100 to 0.1%.

The gradient coating encompass 45 or 360° of the circle, and filters can be from 1 to 8 in. in diameter. The gradients can also be chosen to work with light from UV to far IR. The coatings can be put on filter substrates that include fused silica, BK-7, ZnSe, and Ge. The coating is usually a nickel variant, which is well suited to low-power, room-temperature applications.

The filters render light densities neutral for lasers and wideband applications that use the entire spectrum of white light. And setting up two of the same filters back-to-back can give imaging systems large-aperture neutrality with constant density. Then counterrotating the two filters varies density in both rotational and radial directions. Such a setup would let highresolution cameras operate with full aperture while still being able to attenuate light.

Reynard Corp. Circular Variable Neutral Density Filters

Sponsored Recommendations

April 16, 2025
Clean. Compact. Less heat.
April 16, 2025
SEW-EURODRIVE Introduces DR2C motor, IE5 Ultra-Premium Efficiency Motor
March 31, 2025
Unlike passive products - made of simple carbon springs - the bionic prostheses developed by Revival Bionics are propulsive, equipped with a motor and an artificial Achilles tendon...
March 31, 2025
Electric drives are a key technology for the performance of machines, robots, and power tools. Download this guide for an introduction to high-quality mechatronic drive systems...

Voice your opinion!

To join the conversation, and become an exclusive member of Machine Design, create an account today!