Dichroic Filters

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Dichroic filters can be used with a white LED array to selectively illuminate a sample with a particular color.

Features

• Multilayer Thin Film Coating on Glass Substrates
• Will Not Fade Like Gels or Plastic Filters
• Ø1" Unmounted Filters Sold Individually
• Mounted Filters Available in a Kit

Thorlabs offers high-quality Additive and Subtractive Dichroic Filters with a strong emphasis on durability. Unlike plastic filters or gels, these coatings will not fade with time and can handle much higher temperatures. Our dichroic color filters can be mounted in our Ø1" lens tubes or filter mounts.

Additive and subtractive dichroic filters are used to separate color in CCD imaging, digital projection, machine vision, and printing. These filters allow only a portion of the visible spectrum to pass and reject (reflect) the rest.

In the simplest case, using the red, green, and blue additive filters in succession with a black and white CCD camera, a high-contrast color image may be achieved. Unlike the traditional color CCD, which uses groups of three spatially separated pixels to achieve this effect, using filters maintains the resolution of the camera. In digital projection, additive filters are used to enhance contrast. In machine vision, a single filter can be placed before the CCD camera to increase contrast, which makes sorting items much simpler. Often, copy machines and print preprocessing centers use subtractive filters to make the images that will later be printed in ink.