How To Image A Blue Fluorescence With A Bp470 Blue Bandpass Filter

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1 Application 1 Before: Without a filter over the lens, the 39 5nm LED light overpowers the fluorescence emission that would allow the 2D matrix to be read by the camera. After: A mounted on the camera lens effectively blocks UV wavelengths, passing only the blue fluorescence emission from the 2D matrix while blocking all other unwanted light. Overview: 85% of all the industrial UV fluorescence applications involve imaging a blue fluorescence. Use of a BP470 or similar blue bandpass filter is almost mandatory in order to obtain adequate contrast.

2 Application 2 Before: Very low contrast exists between a white date and lot code and a yellow background After: A placed over the camera lens results in excellent contrast. The BP470 blocks the yellow portion of the spectrum, greatly darkening the background, thus resulting in the white lettering standing out. Overview: When faced with a necessity to image anything white vs. something off-white, slightly yellowish or beige in color, a Blue Bandpass Filter is best suited for the job. A monochrome camera and blue LED illumination will help provide maximum contrast. This includes differentiating metallic silver or chrome from metallic gold or nickel-plated subjects.

3 Application 3 Before: Light from a UV LED light source overpowers blue fluorescence emitted by this part, making the characters virtually undetectable. After: A threaded to the lens blocks the overpowering UV light source, passing only the blue emission in the area of interest. Overview: To create good contrast, any filter used in a fluorescence application (such as the BP470) must block the UV light source in addition to passing only the wavelengths emitted by the fluorophores.

4 Application 4 Before: The contrast between the UV-excited blue fluorescence and background is not sufficient to reliably image the code marking After: A darkens the background by blocking reflected UV light used to excite the blue fluorescence, creating sufficient contrast. Overview: To create good contrast, any filter used in a fluorescence application (such as the BP470) must block the UV light source in addition to passing only the wavelengths emitted by the fluorophores.

5 Application 5 Before: A UV LED ringlight is placed in the field of view, creating a ring of bright points of light as well as noise in the background of this image of a UV excited 2D code emitting blue light. After: A effectively blocks light emitted by the UV LEDs, passing only blue wavelengths produced by the fluorescence emission. Overview: To create good contrast, any filter used in a fluorescence application (such as the BP470) must block the UV light source in addition to passing only the wavelengths emitted by the fluorophores.

6 Application 6 Before: An unfiltered Cognex Checker camera has difficulty distinguishing the presence or absence of a dark grease that is applied to a black seal in two locations. In this case, a Spectrum Illumination SP nm UV light is used to cause the grease to fluoresce a light blue color; however contrast between the grease and the area around the grease is very low. After: Adding a to the lens blocks interfering UV and ambient light, providing outstanding contrast between the phosphorescent grease and surrounding material. Overview: In all UV fluorescence applications it is important to block the UV light from reaching the camera. This is best accomplished in almost all cases by using an appropriate bandpass filter that is the same color as the fluorescence. Application Notes courtesy of MidOpt, Midwest Optical Systems, Inc. For more information, contact Uniforce Sales and Engineering. Fax: (510) Phone: (510) info@uniforcesales.com