An IR Filter For LED Lights?

XtreMe_G said:

so....if i want an ir flashlight.....i'll be better off using an ir led flashlight than using an incan with an ir filter? did i understand that right?

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Most of the output of an incandescent is technically IR (too long a wavelength to be visible) but it's a broad spectrum IR -- only a portion of it is "near-IR" (close to visible range) that is detectable by cameras. However, incan is a MUCH more efficient of IR than visible light. An incan with an IR filter is probably going to be the cheapest way to go, especially if you want high output. If you only need low output IR then I'd go for LED (LED are better for low output in general, as incandescent must get very hot to work well).

One thing that I think would be useful would be a flashlight/LED with 5 separate dies: IR, Red, Green, Blue, UV that could each be switched on and off separately. IR only could be used for use with an IR camera. UV-only mode could be used to check for fluorescent strips in money etc. RGB could be used together for white output. Red-only could be used to preserve night vision, and so on.

By using a filter, you are essentially throwing away everything except the wavelengths you want, all the time. With LEDs you have the option of only using IR output, or a single-colored output when you need it. Note that "White" LEDs won't be able to do this (blue plus a yellow/green phosphor), only LEDs with separate red green and blue output.

There are a lot of flashlights out there that use a high power white LED, surrounded by several small 5mm red LEDs (for night vision preservation). Replacing those red with IR LEDs would give you an optional IR projection mode for use with an IR camera. It also gives you the advantage of turning the IR output off when you don't need it -- incandescent throws IR all the time.

Most of the output of an incandescent is technically IR (too long a wavelength to be visible) but it's a broad spectrum IR -- only a portion of it is "near-IR" (close to visible range) that is detectable by cameras. However, incan is a MUCH more efficient of IR than visible light. An incan with an IR filter is probably going to be the cheapest way to go, especially if you want high output. If you only need low output IR then I'd go for LED (LED are better for low output in general, as incandescent must get very hot to work well).One thing that I think would be useful would be a flashlight/LED with 5 separate dies: IR, Red, Green, Blue, UV that could each be switched on and off separately. IR only could be used for use with an IR camera. UV-only mode could be used to check for fluorescent strips in money etc. RGB could be used together for white output. Red-only could be used to preserve night vision, and so on.By using a filter, you are essentially throwing away everything except the wavelengths you want, all the time. With LEDs you have the option of only using IR output, or a single-colored output when you need it. Note that "White" LEDs won't be able to do this (blue plus a yellow/green phosphor), only LEDs with separate red green and blue output.There are a lot of flashlights out there that use a high power white LED, surrounded by several small 5mm red LEDs (for night vision preservation). Replacing those red with IR LEDs would give you an optional IR projection mode for use with an IR camera. It also gives you the advantage of turning the IR output off when you don't need it -- incandescent throws IR all the time.