Look at above comment about f.lux. You don't even need hardware; you can do it with software. But a quick search for such filters already delivers a lot of results: http://www.amazon.com/s/ref=nb_sb_noss_2?url=search-alias%3D.... Just choosing one of those results randomly (http://www.amazon.com/Green-Onions-Supply-Anti-Fingerprint-P...) seems to address that light spectrum specifically: "They reduce blue light from your screen by 38% over the most harmful portions of the visible light spectrum (380 to 500 nm)"