h a l f b a k e r yWarm and Fussy
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Hmmm. Is the only reason to allow INSTANT darkening?
Polaroid Sunglasses ant that slow are they? |
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I could see this being useful if you can adust the colors.. maybe even be able to add in some custom images.. like something that looks like a pair of eyes so that you can look wide away while you are sleeping. |
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//Polaroid Sunglasses ant that slow are they// |
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Sp. Photochromatic. And yes, it does take about 3 seconds. Polaroid is just a brand, and anyway, it's "polarised" you're referring to, which is simply the filtering out of vertically biased light (including most "glare") in preference to horizontally biased light. |
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What you're looking for is the same technology used for automatic darkening welding helmets. These react quickly enough to prevent eye damage during arc welding (something like 1/1000 of a second reaction time). Typically they use a photovoltaic cell and an LCD layer over the viewing pane. |
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Hm... The problems with this idea are that it still takes time for the cell to absorb the light, produce the electricity, transmit the electricity to the LCD coating, and for the LCD coating to darken after recieving the electric charge from the cell. Generally, I just wear a ballcap with the visor pulled low. Transition lenses work pretty fast. The only drawback they have is that they don't get dark enough for my preference, and don't darken much at all in a car due to the windshield being polarized (transitions are UV activated). Here's what Wikipedia has to say on the subject: |
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//Lenses that darken in response to visible (rather than UV) light would avoid these issues, but they are not feasible for most applications. In order to respond to light, it is necessary to absorb it, thus the glass could not be made to be clear in its low-light state// |
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This is what I don't get. If the glass absorbs light, shouldn't it be getting brighter, not darker? Where does all the light go? |
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into the black hole what is your pupil! |
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I second [Custardguts], the proposed technology is baked by auto-darkening welding goggles, although [goldbb] proposes the PV-module to be in the line of sight. This would be possible with translucent PV-cells, which are currently baking [link]. The efficiency of those cells is projected at ~6%, which is better than the cheap amorphous ones they use in the helmets. This means that at least 6% of the light will be filtered at all times, so the glasses would never be totally clear, (the article does not mention which wavelengths are used/filtered, so maybe it has 100% translucency at visible wavelengths. [+] |
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[Ling] - absorbed light is generally converted into heat. |
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[I_T] - the term photochromatic is rather widely used. Perhaps it's just a proprietary term like polaroid is for polarisation.... |
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Thanks for the links, especially about auto-darkening helmets. |
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Inspired by that, I'd like to suggest that one additional feature might be to make the tinting of the lenses adjustable. |
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gnomethang, The problem isn't really that photochromatic lenses are slow to darken... but that they're slow to become transparent afterwards. It just would have been too long a title to say, "Instant clarifying tinting glasses" :) |
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Custardguts, - I know. A considerable majority do seem to
favour the wrong way of saying and spelling it. It's a bit like
saying 'orientated' instead of 'oriented' - most people seem
to prefer the wrong way of expressing it. |
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