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Thread: does blue light improve peripheral vision in the dark?

  1. #1

    Default does blue light improve peripheral vision in the dark?

    I was reading an Osram patent and in the document, it was noted that the selective blue bands on some of its bulbs can improve peripheral vision.

    The higher color temperature beam has the functional advantage of improved color contrast to aid obstacle detection and road surface orientation. The higher color temperature beam has the further functional advantage of higher effective intensity in peripheral vision, where the retina of the eye has proportionately more photoreceptors of the type that are rods than the type that are cones. Rods are more sensitive to blue light than the cones which are in the retina's central fovea region and are predominantly found in central vision, as discussed in Derlofske et al., “Visual Benefits of Blue Coated Lamps for Automotive Forward Lighting” (Society of Auto. Engineers 2003-01-0930). Higher color temperature light could, in theory, have an advantage in maintaining operator alertness at night. However, there is a tradeoff in that it is understood that while whiter light does not cause an increase in disability glare, there is an increase in perceived discomfort glare, as discussed in Sivak et al., “LED Headlamps: glare and color rendering”, Lighting Res. The. 36,4 (2004) at pp. 295-305.
    https://patents.google.com/patent/US9396925B1/en

    This all sounds very similar to many discussions on this board about how people perceive bluer light to be more glaring than yellower light at the same intensity. However, I don't recall seeing any discussion about the benefits of bluer light--just discussion about how bluer lights increase discomfort glare and is harder for the human visual system to process.

    Now, I understand that just because something is patented doesn't make it a good idea. Nonetheless, I'm curious--is there any validity at all to Osram's claim that bluer light aids in peripheral vision?

  2. #2
    Moderator Alaric Darconville's Avatar
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    Default Re: does blue light improve peripheral vision in the dark?

    Quote Originally Posted by Ls400 View Post
    I was reading an Osram patent and in the document, it was noted that the selective blue bands on some of its bulbs can improve peripheral vision.
    That same region already is not a 'focus' area in the eye.

    Also note: "Higher color temperature light could, in theory, have an advantage in maintaining operator alertness at night." Operator alertness and operator's ability to identify objects in their peripheral vision are two different things.
    It sounds like a lot of handwaving to me.

  3. #3

    Default Re: does blue light improve peripheral vision in the dark?

    as discussed in Derlofske et al., “Visual Benefits of Blue Coated Lamps for Automotive Forward Lighting”
    Uh...yeah, no. For one thing, the researcher's last name isn't Derlofske, it's Van Derlofske. For another, that study, to put it mildly, had issues. NHTSA was thinking of banning blue-tinted halogen bulbs, so Sylvania threw a bunch of money at a usually-reputable research outfit, gave them bulbs, and said "Here, compare these clear bulbs and these blue ones. We're interested (nudge, nudge) in finding out if (wink, wink) there might be some kind of benefit (nudge, nudge) to the blue ones." There was no effort to control for the effects of altering the filament in the manner necessary to get legal output despite the blue filtration, and the effect found (or maybe "found"?) was tiny and questionable, but Sylvania threw it in NHTSA's face and said "SEE! SEE! You can't ban blue bulbs, they're more safer!" (actually what they said was more along the line of "Given the potential safety benefit of blue coatings on halogen bulbs, it may be premature to blah blah blah blah at this time blah blah blah"). NHTSA dropped it, mission accomplished, and Sylvania went to market crowing about the "performance benefits" of their blue bulbs.

    That said, there's some evidence that higher-CCT light might improve peripheral vision in some ways. But Alaric's word "handwaving" is a good one: there are a whole bunch of benefits being claimed for high-CCT light that are either completely or practically bogus.

    And speaking of "completely bogus", that patent you linked contains the completely bogus claim that light passing through the uncolored area forms the hot spot, while light passing through the tinted bands forms the spread light. That's laughable; there is very little consistency across lamps as far as which parts of the beam are formed by which parts of the reflector and/or lens, struck by light from which parts of the filament. Also completely bogus: "The higher color temperature beam has the functional advantage of improved color contrast to aid obstacle detection and road surface orientation".

    And "The higher color temperature beam has the further functional advantage of higher effective intensity in peripheral vision, where the retina of the eye has proportionately more photoreceptors of the type that are rods than the type that are cones. Rods are more sensitive to blue light" is a nonsequitur. The filtration reduces yellow/orange/red light, it does not increase blue light.

    Oh, look: "light for the hot spot without intensity loss from having passed through the coating" HA! Made you say it!

    Just imagine what could be if this amount of effort and drive toward innovation were directed towards putting more light on the road instead of messing around with the color of the light and calling it macaroni.
    Last edited by -Virgil-; 01-09-2019 at 04:19 PM.

  4. #4

    Default Re: does blue light improve peripheral vision in the dark?

    those blue bulbs sometimes are higher wattage than it says on the box, we had customers come it with destroyed headlights, due to excessive heat.

  5. #5

    Default Re: does blue light improve peripheral vision in the dark?

    Quote Originally Posted by -Virgil- View Post
    NHTSA was thinking of banning blue-tinted halogen bulbs
    Were they thinking of banning completely blue bulbs or blubs with any hint of blue on them?

    And speaking of "completely bogus", that patent you linked contains the completely bogus claim that light passing through the uncolored area forms the hot spot, while light passing through the tinted bands forms the spread light. That's laughable; there is very little consistency across lamps as far as which parts of the beam are formed by which parts of the reflector and/or lens, struck by light from which parts of the filament.
    I thought that was partly addressed (what is the size of an average size reflector?):

    The size and positioning of windows 62 is such that the light from filament 24 that passes through them is the light that will strike the portions of reflector 14 that are used for long range light, the so-called hot spot. In axial direction, each clear window 62 is at least as long as filament 24, and filament 24 is in register with and surrounded by window 62. Theoretically, to be perfect, axial extent of window 62 would vary with reflector length and width, but that is not practical since a manufacturer desires to offer only a limited number of types of lamps or perhaps only one standardized replacement lamp for the aftermarket. Thus, as an engineering compromise a reasonable axial extent is chosen for the average size reflector. Since every headlight type built has a different aspect ratio and some are symmetric in the front view, placement of blue coating 60 is of necessity a compromise.
    The filtration reduces yellow/orange/red light, it does not increase blue light.
    Perhaps they meant it increases the proportion of blue light?

    Just imagine what could be if this amount of effort and drive toward innovation were directed towards putting more light on the road instead of messing around with the color of the light and calling it macaroni.
    I recall a test by a reputable magazine discussed on this board that put the Night Breaker Unlimited just behind the Philips Xtreme Vision line in terms of beam reach. If I remember correctly, the difference was about 3 meters in favor of the Philips XV. Perhaps the Osram bulb did well in spite of its bogus blue tint? Interestingly, the Osram did better than its GE counterpart, which has comparatively little blue. Why is that?

    Edit: found the test!

    https://teknikensvarld.se/vart-test-avslojar-vilka-lampor-som-ger-bast-ljus-pa-bilen-181624/
    Last edited by Ls400; 01-11-2019 at 01:28 AM.

  6. #6

    Default Re: does blue light improve peripheral vision in the dark?

    Quote Originally Posted by Ls400 View Post
    I thought that was partly addressed
    How?

    (what is the size of an average size reflector?):
    I'm not sure what the point is of this question.

    Perhaps they meant it increases the proportion of blue light?
    The light-sensing structures they're referring to in the human eye don't react proportionally, but absolutely. The red/yellow/orange light they're filtering out doesn't impede the eye; filtering it out does not improve the light or make it more usable in any real way.

    I recall a test by a reputable magazine discussed on this board that put the Night Breaker Unlimited just behind the Philips Xtreme Vision line in terms of beam reach. If I remember correctly, the difference was about 3 meters in favor of the Philips XV (etc)
    Magazine tests like that are better than the dippy "bulb test" website discussed on here not long ago, because they tend to be at least reasonably scientific in their methods rather than basing them on "beliefs", but the resolution of their tests is still oversold. With only one sample (or only a few samples) of each bulb, three-four-five meter differences can't really tell us anything. Test ten of each and then we can rank-order them, but with small sample size all we can do is say the Osram, GE and Philips high-performance bulbs are categorically enough better than the stock long-life bulb to be worthwhile.

    They used 20 samples of each for the life test, which is a reasonable number. It's also reasonable that they didn't test 10 or 20 samples in the headlamp beam tests, because that would have taken a lot of expensive goniophotometer time.

  7. #7

    Default Re: does blue light improve peripheral vision in the dark?

    Quote Originally Posted by -Virgil- View Post
    How?
    The patent seems to at least partially address your point about how there's little consistency across lamps in which part of the reflector forms the hotspot by saying that the engineers had an "average" reflector in mind. Is there really an "average" size reflector? What are the dimensions of it, if it exists?

  8. #8

    Default Re: does blue light improve peripheral vision in the dark?

    In the late '80s to early '90s it might have meant something to refer to the "average reflector", but even then, it wasn't about size.

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