Rather than the lenses simply getting darker in sunlight, they turn into those mirrored lenses.
Call it a WIBNI if you must, because I can't describe the the chemistry behind the idea (but then, I can't describe the chemistry behind a regular pair of darkening lenses!). The most plausible solution I can imagine would be something like an LCD that silvers over (not unlike the "frosting" bathroom windows), but that seems impractical to me - unless the LCDs were solar powered...-- phoenix, Apr 19 2004 How sunglass technology works http://travel.howst...s.com/sunglass4.htm [Worldgineer, Oct 04 2004, last modified Oct 21 2004] Current technology for modulated reflectivity http://www.iop.org/.../0022-3727/30/2/003Don't buy the article unless you have an advance degree in thies field. [kbecker, Oct 04 2004, last modified Oct 21 2004] (?) One patented method. http://164.195.100....491&RS=PN/6,400,491 [ldischler, Oct 04 2004, last modified Oct 05 2004] At first I decided this was not possible, as the material would need to be reacting to the light it's reflecting. Then I read the page on my link and found that photochromics responds to UV light. So if you make the material reflective to visible light but reactive to UV light, you're set. Then again, who knows if it's chemically possible and it does sound like a WIBNI.-- Worldgineer, Apr 19 2004 mirroring on the inside for vain types!-- po, Apr 19 2004 If you just had photochromic lenses with a slight mirror coating, the mirroring would become more obvious as the lenses darkened. Not quite what you want, but easily possibly with technology that's already out there.
Worldgineer: I'd recommend the the lenses filter U/V (either in the fromt component or further down the lens. Reducing the amount of visible light without dropping the U/V would make the irises open up and let in more U/V, giving you those lovely tanned retinas.-- st3f, Apr 19 2004 Yeah, I thought about that, but removing UV was not part of [px]'s design requirements. Speaking of which, [px]: Why do you find this product desirable?-- Worldgineer, Apr 19 2004 This makes me think of one-way mirrors that work better when there's more light on one side.-- FarmerJohn, Apr 19 2004 [wr] is it necessary to specify a desirability? who do the devil is [px]? oh you mean phoe!-- po, Apr 19 2004 Off the top, I’d suggest finding a polymer that expanded in the presence of an environmental condition. Then you could build a multi-layer dielectric mirror that would reflect differently according to conditions. There are polymers that swell in the presence of heat, and there might be those that reversibly swell in UV.-- ldischler, Apr 19 2004 [po] It's not, but it does help a product sell. Yes, I mean [phoenix]. That's what I get for over-abbreviating.-- Worldgineer, Apr 19 2004 is phoe selling or suggesting?-- po, Apr 19 2004 Don't know. Even if just suggesting, [feniks] likely finds some feature of this product desirable, or would not likely spend the effort to post it.-- Worldgineer, Apr 19 2004 Filtering UV is SOP for sunglasses, no? I thought there was some sort of regulation regarding minimum protection provided... Oh, wait, I see what you mean. Yeah, UV reactive is what I was thinking - just like a regular pair of photochromic lenses.
And mind, I'm not looking for true one-way mirrors. I'm just trying to achieve that mirrored look some sun glasses have.
The motivation is purely style. No one else seems to have thought of it yet. I happened to be out in the sun recently, wished I had transitional lenses and thought "Hey, wouldn't it be neat if..."-- phoenix, Apr 19 2004 Since the glasses only have to turn into mirrors when there is light around, the rims could have solar cells installed to power any LCD like device. There are materials that turn reflective when an electric field is applied. Can't find a good link, the technology is still too new so this may still be a little too advanced.-- kbecker, Apr 19 2004 //I happened to be out in the sun recently// look I can only help to a certain extent... ;)-- po, Apr 19 2004 Yeah, and I'm not much to work with! Why do you think they only let me out once in a while?-- phoenix, Apr 20 2004 random, halfbakery