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I've been curious about something in AR for a while, and I can't seem to find the right terms to query this. Why can't ambient light be used for illumination,

by lukevp 6y ago

I've been curious about something in AR for a while, and I can't seem to find the right terms to query this. Why can't ambient light be used for illumination, and an LCD + polarizer to darken each pixel? If you can approximate the illumination of each point of light going through the LCD (for example, with an outward-facing camera above each lens capturing a full-color image and interpolating it down to where it would be overlayed on top of the LCD) you would know how much you would need to darken each sub-pixel's color to compensate for the light coming in. Then it would be super low-power since there would be no backlight. Also, if you wanted "Transparent" mode you could make it fairly clear. I'm sure there's some reason this is untenable but I'm not really sure what it is - perhaps the inability to be accurate with the compensation?

ahupp 6y ago
If you can only subtract light the contrast of what you're viewing against the background will always be poor, almost by definition. Also doesn't handle color.
- lukevp 6y ago
  Why could it not handle color if it had R/G/B subpixels and adapted the intensity of each pixel based on the color of the light passing through that area of the screen? The intensity of light is quite high outside, could an LCD not darken it enough to have sufficient contrast if you were OK with it only working outside?
  - sangfroid_bio 6y ago
    Just do a quick search for transparent LCDs, I think it will answer your question. (Not enough light gets through, the result looks more like high resolution stained glass than a Retina display)
  - Buttons840 6y ago
    How could you determine the color of the light passing though that area of the screen?
  - numpad0 6y ago
    LCD can’t darken, aren’t that transparent in the first place, also can’t focus without microlenses and you won’t be able to look through microlenses. If you still think it viable you can prototype the optics you described using old Nokia phone LCDs or some later GameBoy models that has easily removable backlights.
    - anmorgan 6y ago
      Are you being specific about the word darken? Because LCDs are design to either allow or block light. So technically an LCD can "darken" incoming light. But I think the point of inconsistent lighting from the environment would be the biggest challenge. The best example of transparent display I've seen in production is:https://glas.johnsoncontrols.com/ https://glas.johnsoncontrols.com/ But the material on that seems darker and I believe they use an edge light to provide higher contrast. I think the distance from the eye, as well, would be difficult if you aren't doing some type of projection, like what is used in the the article.
      - numpad0 6y ago
        Darken as in response to “can’t LCD darken enough” in parent. Anyways any LCD can be a transparent LCD if you peel off backlight layers if you want to experiment with. Search for “DIY transparent LCD” or “LCD side panel casemod”

by lukevp 6y ago

ahupp 6y ago

If you can only subtract light the contrast of what you're viewing against the background will always be poor, almost by definition. Also doesn't handle color.

lukevp 6y ago
Why could it not handle color if it had R/G/B subpixels and adapted the intensity of each pixel based on the color of the light passing through that area of the screen? The intensity of light is quite high outside, could an LCD not darken it enough to have sufficient contrast if you were OK with it only working outside?
- sangfroid_bio 6y ago
  Just do a quick search for transparent LCDs, I think it will answer your question. (Not enough light gets through, the result looks more like high resolution stained glass than a Retina display)
- Buttons840 6y ago
  How could you determine the color of the light passing though that area of the screen?
- numpad0 6y ago
  LCD can’t darken, aren’t that transparent in the first place, also can’t focus without microlenses and you won’t be able to look through microlenses. If you still think it viable you can prototype the optics you described using old Nokia phone LCDs or some later GameBoy models that has easily removable backlights.
  - anmorgan 6y ago
    Are you being specific about the word darken? Because LCDs are design to either allow or block light. So technically an LCD can "darken" incoming light. But I think the point of inconsistent lighting from the environment would be the biggest challenge. The best example of transparent display I've seen in production is:https://glas.johnsoncontrols.com/ https://glas.johnsoncontrols.com/ But the material on that seems darker and I believe they use an edge light to provide higher contrast. I think the distance from the eye, as well, would be difficult if you aren't doing some type of projection, like what is used in the the article.
    - numpad0 6y ago
      Darken as in response to “can’t LCD darken enough” in parent. Anyways any LCD can be a transparent LCD if you peel off backlight layers if you want to experiment with. Search for “DIY transparent LCD” or “LCD side panel casemod”