Wood/Glass/Metal Can One-Way Glass Be Made With Projected Light?

[madou0016]

Hello, I'm wondering if you can inform me about that kind of light which be projected on a glass and it helps us to see it's reflection only for the viewer and not for anyone the other side .
all proposals and methods are welcome.
even if it is necessary for the light to pass on a chemical substance.
thank you cordially
Mehdi from the National School of Marine Sciences in Algeria

 

[phinds]

It's not up to the light, it's up to the glass. One-way glass has been around for decades.

 

[madou0016]

It's not up to the light, it's up to the glass. One-way glass has been around for decades.

thanks for your answer, but i am looking for a solution for the light.
and One-way glass you can not see the other side

 

[phinds]

thanks for your answer, but i am looking for a solution for the light.
and One-way glass you can not see the other side

? One-way glass does exactly what your picture shows.

 

[DaveC426913]

? One-way glass does exactly what your picture shows.

Weeeelllll, it does exactly the opposite of what his diagram shows.

With one-way glass, the person in darkness can see the person in the lit room. Whereas the person in the lit room can't see the person in darkness.

 

[DaveC426913]

Hello, I'm wondering if you can inform me about that kind of light which be projected on a glass and it helps us to see it's reflection only for the viewer and not for anyone the other side .

Madou, if you move the light to the opposite side of the glass, without changing anything else, you have your solution.

 

[phinds]

Weeeelllll, it does exactly the opposite of what his diagram shows.

Good catch, Dave. I was ignoring where the light is because I knew the solution couldn't be with the light.

 

[madou0016]

Madou, if you move the light to the opposite side of the glass, without changing anything else, you have your solution.

thank you for your answer, the final result that I want to get it is like a stained glass just in projecton a light.
if you see what I want!
like this ! but only with light

 

[phinds]

thank you for your answer, the final result that I want to get it is like a stained glass just in projecton a light.
if you see what I want!
like this ! but only with light

This is just tinted glass (not what "stained glass" normally means, but not too different), and the view from the inside is partially obstructed by the glass. Again, the solution is with the glass, not with the light.

 

[DaveC426913]

Diagram added in post 6, for clarity.

 

[Bystander]

Window tinting?

 

[madou0016]

Window tinting?

Yes , but only on projecting light

 

[phinds]

Yes , but only on projecting light

I have no idea what you are talking about. Tinted windows are tinted regardless of light, unless you are talking about the kind of light that is used in glasses (spectacles) so that they slowly turn dark when you go out in the sunlight. In either case, the solution is in the glass, not the light and the visibility is the same from both sides

 

[sophiecentaur]

Glass of any kind is no truly ‘one way’. It will let the same fraction through from either direction. Ant one way system relies on the Observer side being dimmer than the place he is looking at. The performance is always better if the Observed Side of the glass has stripes of mirror. This increases the contrast between the bright shiny strips and the dark gaps as seen from the Observed side.

 

[phinds]

Glass of any kind is no truly ‘one way’. It will let the same fraction through from either direction. Ant one way system relies on the Observer side being dimmer than the place he is looking at. The performance is always better if the Observed Side of the glass has stripes of mirror. This increases the contrast between the bright shiny strips and the dark gaps as seen from the Observed side.

Actually, it's not normally done in strips. Here's from wiki:

A one-way mirror has a reflective coating applied in a very thin, sparse layer -- so thin that it's called a half-silvered surface. ... The room in which the glass looks like a mirror is kept very brightly lit, so that there is plenty of light to reflect back from the mirror's surface

 

[sophiecentaur]

Actually, it's not normally done in strips. Here's from wiki:

The simplest example (that was used in shops and offices) used quite wide silvered strips which I suspect was a modified regular mirror. The lowest tech you could imagine and it did the job.
Other technologies (better) are available for Physicists.

 

[phinds]

The simplest example (that was used in shops and offices) used quite wide silvered strips which I suspect was a modified regular mirror. The lowest tech you could imagine and it did the job.

Interesting. I've never seen one of those. A couple of the stores I worked in parttime when I was young had the kind wiki talks about and of course all the cop shows have that kind as well.

 

[sophiecentaur]

Interesting. I've never seen one of those. A couple of the stores I worked in parttime when I was young had the kind wiki talks about and of course all the cop shows have that kind as well.

The strips(iirc) perhaps had a pitch of 15cm. Not too coarse to spot and recognize a customer coming into the shop and, of course, the local glazier could make up a replacement to any size.

EDIT: that's 15mm and not 15cm. Durrr!

 

[sysprog]

Hmm -- what kind of light . . . oh, yes, one or more of the impossible kinds . . .

Merci, Monsieur Magritte.

 

[phinds]

Hmm -- what kind of light . . . oh, yes, one or more of the impossible kinds . . .

? What on Earth does that image have to do with this thread?

 

[sophiecentaur]

? What on Earth does that image have to do with this thread?

As with many, the thread has a mind of its own. The agenda was never really declared.

 

[phinds]

As with many, the thread has a mind of its own. The agenda was never really declared.

Well, c'est la vie

 

[sysprog]

? What on Earth does that image have to do with this thread?

What does the "kind of light" have to do with the transparencies and reflectivities of a window pane? The image was by me intended as a reductio ad absurdum in support of the position already expressed by you; it's a fantasy image in which light behaves inconsistently in a manner depending on viewer attention viewpoint. How can it be daytime in the sky while it's night-time on the ground in what is otherwise approximately the same location?

 

[DaveE]

Since you asked in a physics forum, here's a physics answer:
https://en.wikipedia.org/wiki/Optical_isolator

 

[anorlunda]

Please, let's try to focus on helping the OP.

 

[sysprog]

Please, let's try to focus on helping the OP.

Thanks for the gentle tempering. I think the OP was satisfied with the responses, and I think that the response of @DaveE was especially informative and on-point, as it pointed to something that elucidates principles which should adequately address the inquiry. For my part I'll try to contain any over-indulgence toward which I might over-obtend.

 

[DaveC426913]

I have a question for the OP for clarification of the end goal:

It is necessary that the light be where it is (i.e. on the "I can see" side of the glass), or is that your preconception of how it would work?

In other words, eliminate all the constraints you can , and just tell us only what result you want to achieve.

 

[Nik_2213]

Have you seen the clever ads in eg bus windows and rear of taxis where the bold external ad has a grid of small holes ? Back of ad is a neutral gray, does not catch the eye, allows 'legal' visibility outbound. The bold exterior does so catch the eye, so blocks view in-bound.

Turned about, this could work for OP...

PS: check out 'Peppers Ghost' illusion and its kin...
https://en.wikipedia.org/wiki/Pepper's_ghost

 

[DaveC426913]

Have you seen the clever ads in eg bus windows and rear of taxis where the bold external ad has a grid of small holes ? Back of ad is a neutral gray, does not catch the eye, allows 'legal' visibility outbound. The bold exterior does so catch the eye, so blocks view in-bound.

Turned about, this could work for OP...

Except it operates on the same principle as the one-way glass solution we've been describing.
It requires that the blocking side be well-lit, and the see-through side be in reduced light.

 

[sophiecentaur]

over-obtend.

Now that's a word we don't often come across. Literacy is not yet dead on PF.
More please.

 

[sysprog]

over-obtend.

Now that's a word we don't often come across. Literacy is not yet dead on PF.
More please.

I have to confess to my being somewhat of an inconflagrator in that regard.

Basketball squabbler's lament:
I was set; you were charging. You were intruding; I was merely obtruding obtendatorily against your inrighteous incursion.

 

[sophiecentaur]

I am totally discomknockerated by that.

 

[sysprog]

Now that's a word we don't often come across. Literacy is not yet dead on PF.
More please.

Just for fun: the word 'surgery' is derived from 'chirurgery' (i.e. doing/practice by application of hands).

 

[sophiecentaur]

. . . as in chiropractor. Etc etc

 

[Marco Aquino]

Measure the length between the person (A)
( wants to see) and glass. It would be a tinted glass at the measurement somewhere in th middle of darkest and brightest. Depending on how far person A is from the glass.

Simplest way I can put it. Always better way

 

[DaveC426913]

Measure the length between the person (A)
( wants to see) and glass. It would be a tinted glass at the measurement somewhere in th middle of darkest and brightest. Depending on how far person A is from the glass.

Simplest way I can put it. Always better way

Sorry, Can you put it less simply?
How does the distance between a subject and the glass make a difference?
And what does 'somewhere in the middle of darkest and brightest' mean?

 

[phinds]

Sorry, Can you put it less simply?
How does the distance between a subject and the glass make a difference?
And what does 'somewhere in the middle of darkest and brightest' mean?

Yeah, @Marco Aquino I also didn't understand what you said. I think perhaps there's a language problem.

 

[DaveC426913]

I think perhaps there's a language problem.

Sure but, like a Universal Translator, if we get enough data, we can probably interpolate the meaning.

 

[sophiecentaur]

Sure but, like a Universal Translator, if we get enough data, we can probably interpolate the meaning.

Perhaps the Vogon version would be more understandable?

 

[DaveC426913]

I shall rend thee in the gobberwarts with my blurglecruncheon, See if I don't!

 

[sophiecentaur]

We shall be keelhauled by the constabulary if we veer off topic any more, I think.

 

[DaveC426913]

Think of it as doing our part to keep the thread at the top of New Posts until the OP returns.
There should be a Trophy for that!

 

[phinds]

I swear to Pete, you guys are going to reticulate my framis.

 

[sysprog]

. . . as in chiropractor. Etc etc

Right. The problem MDs in general have with chiropractors is the pseudo-scientific medical model set upon which the guild of chiropractic practicianship historically founded itself. I think that many MDs recognize that some chiropractors are very skilled at pain-alleviating manipulations.

 

[sysprog]

I shall rend thee in the gobberwarts with my blurglecruncheon, See if I don't!

Shades of Joyce!

 

[jim mcnamara]

Well, ReJoyce. You al have just ruined a thread. It goes down to GD where nonsense can roam free.

 

[Baluncore]

In this thread we have had tinted glass mentioned, but nowhere did I see mention of a Circularly Polarised film being used. CP film can be LH or RH, so half the random light gets in, half the random internal light gets out. But light that crosses the film is unable to return through the film because the polarisation is reversed by reflection.
Visual displays often have a thin film to prevent reflections from the external surface, they are also CP so you will not see your reflection in the display surface.

 

[sysprog]

In this thread we have had tinted glass mentioned, but nowhere did I see mention of a Circularly Polarised film being used. CP film can be LH or RH, so half the random light gets in, half the random internal light gets out. But light that crosses the film is unable to return through the film because the polarisation is reversed by reflection.
Visual displays often have a thin film to prevent reflections from the external surface, they are also CP so you will not see your reflection in the display surface.

I'm reminded of the little (maybe $\rm{1cm}$ diameter circular film area) card (maybe $\rm{3cm^2}$) card that came with cheap (around/maybe $5-$8) polaroid sunglasses in the mid-'70s -- you could rotate the card with respect to the sunglass lens and see the light go from sunglass-dark to almost completely dark $\dots$

Around 20 years ago I looked indignantly at a 20-something kid who was clerking in a sunglass/opticks ($\leftarrow$ Isaac Newton's spelling of the word which in (what IBM calls) US English would be spelled/spelt 'optics' -- Newton meant the principles more than the instrumentation -- I mean the gear/kit) shop at a mall -- he was pointing and telling regarding which sunglasses had polarized ($\leftarrow$ US English spelling) lenses -- I said that if he would please just hand to me a pair that he knew to be polarized, that I could rotate them and see for myself which of the sunglasses in the display case were or weren't polarized --

At first he just handed me the glasses and showed a bewildered look on his face -- then I handed him back the glasses and said hold up the glasses and look through them at that display case and rotate the glasses and you'll see which glasses have polarized lenses -- accordingly, he looked and he saw, and he gave a smile $\dots$

 

[Lewis Goudy]

Weeeelllll, it does exactly the opposite of what his diagram shows.

With one-way glass, the person in darkness can see the person in the lit room. Whereas the person in the lit room can't see the person in darkness.

Another example of an "optical diode" is a grid or screen which is close to the eye and distant from the object observed. Even after giving effect to the circumstance that the level of illumination in my office is likely twenty times greater than that of the roadway in front of my house, I can resolve quite clearly what the vehicle is, a truck or a jeep or pair of babes on bikes passing by, that one is cuter than the other--yet all they see looking my way is a window, perhaps make out that it is fitted with blinds rather than curtains. Even at dusk when it is actually brighter in my room than outside this remains the case; it is a matter of truncation of a cone of two nappes at different distances from the vertex.

 

[DaveC426913]

Another example of an "optical diode" is a grid or screen which is close to the eye and distant from the object observed. Even after giving effect to the circumstance that the level of illumination in my office is likely twenty times greater than that of the roadway in front of my house, I can resolve quite clearly what the vehicle is, a truck or a jeep or pair of babes on bikes passing by, that one is cuter than the other--yet all they see looking my way is a window, perhaps make out that it is fitted with blinds rather than curtains. Even at dusk when it is actually brighter in my room than outside this remains the case; it is a matter of truncation of a cone of two nappes at different distances from the vertex.

That is ... an astonishingly simple and elegant solution.