Transparent surfaces that become opaque

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Discussion Overview

The discussion revolves around materials that can transition from transparent to opaque under certain conditions, particularly in response to bright light or electrical stimuli. Participants explore various applications and technologies related to this concept, including potential uses in windows and display technologies.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant inquires about materials that become opaque when bright light is shined on them, specifically for use as windows that can project images.
  • Another participant references photochromic lenses as a potential solution.
  • Concerns are raised about the effectiveness of projectors in bright sunlight, suggesting that an LCD window with separate control might be necessary.
  • Participants mention the existence of glass that becomes opaque when an electric current is applied, with links to relevant products.
  • There is skepticism regarding the utility of electrochromic windows in bright conditions, with a preference expressed for higher resolution display technologies without moving parts.
  • A question is posed about whether switchable glass would revert to transparency during a power outage, prompting clarification on the technology behind smart glass.
  • Clarifications are provided regarding the operation of switchable glass, emphasizing that it requires a voltage to remain transparent and that power loss does not affect its functionality.

Areas of Agreement / Disagreement

Participants express various viewpoints on the effectiveness and practicality of different materials and technologies, indicating that multiple competing views remain without a consensus on the best solution.

Contextual Notes

Participants discuss limitations related to sunlight interference and the operational requirements of different technologies, but these aspects remain unresolved.

LightningInAJar
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TL;DR
Surfaces that change transparency.
Are there any materials that go from transparent to opaque when a bright light is shined on it? In particular I would like something that acts like a window until I project a movie onto it and then is opaque in the regions where the light hits it at certain levels of brightness.
 
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LightningInAJar said:
Are there any materials that go from transparent to opaque when a bright light is shined on it? In particular I would like something that acts like a window until I project a movie onto it and then is opaque in the regions where the light hits it at certain levels of brightness.
If sunshine falls on the window, or it is a bright day, the window will become opaque.
No projector can compete with sunlight.
Maybe an LCD window is needed with a separate control.
 
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You can also get glass which becomes opaque when you pass a current through it.

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https://www.smartglassinternational.com/electric-switchable-glass/
 
Baluncore said:
If sunshine falls on the window, or it is a bright day, the window will become opaque.
No projector can compete with sunlight.
Maybe an LCD window is needed with a separate control.
I would not use it in sunlight.
 
Jarvis323 said:
You can also get glass which becomes opaque when you pass a current through it.
Erm. Does this means that these will switch transparent in case of a power outage?

Just asking :doh:
 
Rive said:
Erm. Does this means that these will switch transparent in case of a power outage?
Smart glass does not have “a current pass through it” as that would be very inefficient. Switchable glass has a liquid crystal film, between transparent conductive layers, within the laminate that change optical characteristics when subjected to an electric field.
The glass becomes transparent only when a voltage is applied.
Loss of power does not lead to loss of dignity.
 
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