Hey Slize, if you're still out there, can you refresh my memory:
1. You stated that you could use two separate prisms both filled with oil, and that the 2nd cancels the first's chromattic aboration. If this is so, would it work with both filled with water, as well?
2. In either case, why did the german website insist that one be filled with oil? If either water or oil cancels the other's chromattic shift, why have separate types of liquids in each prism?
1. You stated that you could use two separate prisms both filled with oil, and that the 2nd cancels the first's chromattic aboration. If this is so, would it work with both filled with water, as well?
2. In either case, why did the german website insist that one be filled with oil? If either water or oil cancels the other's chromattic shift, why have separate types of liquids in each prism?
Jude,
It is the same principle as achromatizing a lens where two different materials are used. If both prisms consist of the same material greater distortions will occur because one material bends differing wavelengths of light in a different manner. Going through two lenses will compound the problem. This is why two or three materials are used with differing index and dispersion values. Also the values are carefully selected to compenstate for each lenses abberations.
Anywhy, have you tried to make round prisms out of PVC pipe. I have this Idea for an adjustable or variable anamorphic which uses two prisms made from cut sections on PVC or ABS pipe. Then glass or acrylic is used for the ends.
Hezz
It is the same principle as achromatizing a lens where two different materials are used. If both prisms consist of the same material greater distortions will occur because one material bends differing wavelengths of light in a different manner. Going through two lenses will compound the problem. This is why two or three materials are used with differing index and dispersion values. Also the values are carefully selected to compenstate for each lenses abberations.
Anywhy, have you tried to make round prisms out of PVC pipe. I have this Idea for an adjustable or variable anamorphic which uses two prisms made from cut sections on PVC or ABS pipe. Then glass or acrylic is used for the ends.
Hezz
hi jude,
i don't really if it works with two prisms filled with water, neither i don't know the angles for this then...
but i do know it works really good with both prisms filled with glycerine oil... cause the angles of the prisms are nearly both the same, so chromatic distortion is really weak, practically not visible...
it is the same with prisms totally made out of glas... you use the first to make the rainbow colors visible out of light and a second made out of the smae type of glas, to put the light ray back together to one piece; so the smaller the angle differneces the smaller the chromatic shift...
the german site insits in having one prism filled with water and the other filled with terpentine (not glycerine) oil... but the water gets blury and the terpentine oil destroys the silicone after a time so the prism will get leaky...
i already posted the angles for the prisms both filled with glycerine oil several posts ago, cause it is really hidden on the german site...
i don't really if it works with two prisms filled with water, neither i don't know the angles for this then...
but i do know it works really good with both prisms filled with glycerine oil... cause the angles of the prisms are nearly both the same, so chromatic distortion is really weak, practically not visible...
it is the same with prisms totally made out of glas... you use the first to make the rainbow colors visible out of light and a second made out of the smae type of glas, to put the light ray back together to one piece; so the smaller the angle differneces the smaller the chromatic shift...
the german site insits in having one prism filled with water and the other filled with terpentine (not glycerine) oil... but the water gets blury and the terpentine oil destroys the silicone after a time so the prism will get leaky...
i already posted the angles for the prisms both filled with glycerine oil several posts ago, cause it is really hidden on the german site...
Slize, yes actually I'm going off of your posts from months ago, I finally am having time to sit down and actually do the new angles.
Hezz: Yes I am using the square fencepost idea, (rather than large round PVC) I'm trying 4" first to see if it will do the job. If not I'll at least make the front lense 5" (square with rounded corners).
I already have it cut to the angles Slize specified and have acryllic windows cut to size to just plop into place via E-6000.
In my opinion both prisms filled with water is the "best". (Assuming that the 2nd water prism can correct the chromatic issues). If Algea develops I envision just unplugging the prism, draining it, and re-filling it. Mineral oil costs money, and you have to be more careful using it. However, the biggest obstacle here as you two pointed out is whether or not water can actually correct the chromatic issues as well as some other material, and at what angles? Might just have to try and see I guess....
I believe I remember in a thread Tor started that at one point he claimed both filled with water seemed to work fine, then later recanted it, but was not specific why. I am wondering now if it corrects the chromatic issues, but just not as well, at these specific angles.
By the way, I made water prism over a year and a half ago for my first prototype. I keep it out of the light when not in use, and it is still crystal clear (no algae).
A follow up question:
1. Since the projected image has to pass through both your liquid material (glycerine/mineral oil/water/etc) AND the four edges of both prisms (glass or acrylic) is there any thoughts on how much more glass or acrylic bends the light passing through it? Meaning, based on scientific principals, is it feasible to prove that one material is better than another to use for the edges of the prisms? (Glass vs. acrillic) Or is this a non-issue..? glass and acrillic affect light almost identically, or negligably different?
Hezz: Yes I am using the square fencepost idea, (rather than large round PVC) I'm trying 4" first to see if it will do the job. If not I'll at least make the front lense 5" (square with rounded corners).
I already have it cut to the angles Slize specified and have acryllic windows cut to size to just plop into place via E-6000.
In my opinion both prisms filled with water is the "best". (Assuming that the 2nd water prism can correct the chromatic issues). If Algea develops I envision just unplugging the prism, draining it, and re-filling it. Mineral oil costs money, and you have to be more careful using it. However, the biggest obstacle here as you two pointed out is whether or not water can actually correct the chromatic issues as well as some other material, and at what angles? Might just have to try and see I guess....
I believe I remember in a thread Tor started that at one point he claimed both filled with water seemed to work fine, then later recanted it, but was not specific why. I am wondering now if it corrects the chromatic issues, but just not as well, at these specific angles.
By the way, I made water prism over a year and a half ago for my first prototype. I keep it out of the light when not in use, and it is still crystal clear (no algae).
A follow up question:
1. Since the projected image has to pass through both your liquid material (glycerine/mineral oil/water/etc) AND the four edges of both prisms (glass or acrylic) is there any thoughts on how much more glass or acrylic bends the light passing through it? Meaning, based on scientific principals, is it feasible to prove that one material is better than another to use for the edges of the prisms? (Glass vs. acrillic) Or is this a non-issue..? glass and acrillic affect light almost identically, or negligably different?
Jude,
When a ray of light ( or wave ) traveling through the air strikes a more dense material it causes the photon to slow down. This is what actually causes the refracting or bending of the light along with the angle that it originally strikes the surface. The more dense the material is the greater it will refract the light. So glass will refract more than plastic and plastic will refract more than water. If you look at these substances refractive index you will see that glass is higher than plastic. And both are higher than water.
Now to complicate things even more this refracting of light is not linear for all wavelengths of light. So you can focus say one color of light and the other colors will be somewhat out of focus because they refract a different amount then the first color.
Generally they try to correct for the three primary light colors but more expensive lenses correct for the whole color spectrum. The three color correction is the more common and the lenses are called achromatic lenses.
Sometimes you can get by with no color correction if the image does not have to be high resolution. I wonder if no color correction in the prisms would create a slightly blurred effect that would mask screen door but would still be accurate enough to not significantly impair viewing.
Have you tired tapping a brass fitting into the top of your lenses so that you can empty and refill them easily if necessary.
Hezz
When a ray of light ( or wave ) traveling through the air strikes a more dense material it causes the photon to slow down. This is what actually causes the refracting or bending of the light along with the angle that it originally strikes the surface. The more dense the material is the greater it will refract the light. So glass will refract more than plastic and plastic will refract more than water. If you look at these substances refractive index you will see that glass is higher than plastic. And both are higher than water.
Now to complicate things even more this refracting of light is not linear for all wavelengths of light. So you can focus say one color of light and the other colors will be somewhat out of focus because they refract a different amount then the first color.
Generally they try to correct for the three primary light colors but more expensive lenses correct for the whole color spectrum. The three color correction is the more common and the lenses are called achromatic lenses.
Sometimes you can get by with no color correction if the image does not have to be high resolution. I wonder if no color correction in the prisms would create a slightly blurred effect that would mask screen door but would still be accurate enough to not significantly impair viewing.
Have you tired tapping a brass fitting into the top of your lenses so that you can empty and refill them easily if necessary.
Hezz
Guys,
There are a few advantages to making the prisms out of round PVC or ABS pipe. The pipe is available is several sizes and thicknesses so you can route a ledge into the edge to take the clear side panels. Also you can mount the lenses inside another round tube to hold them and the last and best advantage is that you can rotate the prisms axially within the mounting tube away from each other to correct for barrel distortion.
Hezz
There are a few advantages to making the prisms out of round PVC or ABS pipe. The pipe is available is several sizes and thicknesses so you can route a ledge into the edge to take the clear side panels. Also you can mount the lenses inside another round tube to hold them and the last and best advantage is that you can rotate the prisms axially within the mounting tube away from each other to correct for barrel distortion.
Hezz
On your (1st of 2) posts, two points: 1. I think there IS a slight blurred effect which in effect slightly masks screen door but doesn't really affect the picture. The squeeze is already squishing the pixels so there is an additional screen door masking going on there.
Also, on the same post... in reply to the subject of bending of light, can you comment on whether you think plastic is in any way advantageous over glass, since it doesnt' bend the light as much?
Hezz, could you by chance draw a 3-d drawing of what you mean in your (2nd of 2) posts:
* I understand the point about mounting more easily inside a larger round tube, thats an excellent point!!
* You lost me on routing a "ledge"? into the edge? Why would you want to do that, what do you use "clear side panels" for? An illustration woudl work wonders here
* I believe I understand why one would want to rotate the prisms axially but I do not see how you can do that if you have it surrounded by a larger tube, you'll run out of room, unless you have a tube almost twice the size? Again, an illustration might be cool.
Great ideas Hezz. The downside of a round shape is potential clipping on the sides especially when you tilt the lense that's further away from the projector up or down, the edges, now rounded instead of square, might clip the square projector image. It seems more intuitive to make it squarish, since the image is squarish. On the subject of mounting tube into tube, if you use the fenceposts, if 4" works, you can find a 5" fencepost to mount around the 4" prisms.
Lastly, on draining the prism, I was just thinking of tapping a screw of some sort into the side and putting silicon on it to seal, then extract it every two years to empty the water if it develops algae. In two years, I figure, the lense may not have as much use anyway, as projector technolgy might somehow support 16:9 and 2.35 out of the box.
Also, on the same post... in reply to the subject of bending of light, can you comment on whether you think plastic is in any way advantageous over glass, since it doesnt' bend the light as much?
Hezz, could you by chance draw a 3-d drawing of what you mean in your (2nd of 2) posts:
* I understand the point about mounting more easily inside a larger round tube, thats an excellent point!!
* You lost me on routing a "ledge"? into the edge? Why would you want to do that, what do you use "clear side panels" for? An illustration woudl work wonders here
* I believe I understand why one would want to rotate the prisms axially but I do not see how you can do that if you have it surrounded by a larger tube, you'll run out of room, unless you have a tube almost twice the size? Again, an illustration might be cool.
Great ideas Hezz. The downside of a round shape is potential clipping on the sides especially when you tilt the lense that's further away from the projector up or down, the edges, now rounded instead of square, might clip the square projector image. It seems more intuitive to make it squarish, since the image is squarish. On the subject of mounting tube into tube, if you use the fenceposts, if 4" works, you can find a 5" fencepost to mount around the 4" prisms.
Lastly, on draining the prism, I was just thinking of tapping a screw of some sort into the side and putting silicon on it to seal, then extract it every two years to empty the water if it develops algae. In two years, I figure, the lense may not have as much use anyway, as projector technolgy might somehow support 16:9 and 2.35 out of the box.
Jude,
I will try to come up with a solid model to illustrate my concepts. I know it is hard to visualize from words what another is thinking.
The only disadvantage that I can see with round prisms is that they must be a little larger so they can let the whole rectangular image pass.
In fact some plastics have higher light transmissivity in the visible spectrum that a lot of glasses. Plastics have many advantages over glass when it comes to lens manufacture but they have one major disadvantage compared to glass which is huge. There are not enough optically clear plastics types which have optimal complementary refractive and dispersion indexes to make a highly abberation free lens. A plastic lens system must have more lenses to function well and it cannot approach the quality of glass lens systems for high end resolution.
I modeled a large aperture cooke triplet lens in glass and plastic and optimized both. The glass lens system has greater than ten times the resolution than the plastic. The plastic could perhaps be enhanced if I could get every known optically clear plastic information but it is difficult to get because most plastics don't have published detailed optical property information.
One interesting thing about the liquid filled prisms is that there are three substances that the light passes through. It might be possible to find a good combination of substances so that the lens has some abberation correction.
For instance one glass panel could be a crown glass and the rear a flint glass. You could also make some abberation control with plastic by making one window out of acrylic and the other out of polycarbonate.
Another possibility is to make one prism out of clear polyester casting resin.
Hezz
I will try to come up with a solid model to illustrate my concepts. I know it is hard to visualize from words what another is thinking.
The only disadvantage that I can see with round prisms is that they must be a little larger so they can let the whole rectangular image pass.
In fact some plastics have higher light transmissivity in the visible spectrum that a lot of glasses. Plastics have many advantages over glass when it comes to lens manufacture but they have one major disadvantage compared to glass which is huge. There are not enough optically clear plastics types which have optimal complementary refractive and dispersion indexes to make a highly abberation free lens. A plastic lens system must have more lenses to function well and it cannot approach the quality of glass lens systems for high end resolution.
I modeled a large aperture cooke triplet lens in glass and plastic and optimized both. The glass lens system has greater than ten times the resolution than the plastic. The plastic could perhaps be enhanced if I could get every known optically clear plastic information but it is difficult to get because most plastics don't have published detailed optical property information.
One interesting thing about the liquid filled prisms is that there are three substances that the light passes through. It might be possible to find a good combination of substances so that the lens has some abberation correction.
For instance one glass panel could be a crown glass and the rear a flint glass. You could also make some abberation control with plastic by making one window out of acrylic and the other out of polycarbonate.
Another possibility is to make one prism out of clear polyester casting resin.
Hezz
Hi guys.
It's my first post here... (I use to surf in my language forum...) I have realized some prototypes of anamorphic lens, here are some result.
I hope that it is of interest for you...
They are all done with normal glass and glycerin... The Case is made in "Al" cutted by laser!
The video output result is quite good...
Here you can find my collection of information about Anamorfic Lens but I'm sorry is written in Italian (you can try the alatavista translator...)
http://www.realwc.com/anamorfico/anamorfico.htm
Cu
UbyOne
It's my first post here... (I use to surf in my language forum...) I have realized some prototypes of anamorphic lens, here are some result.
I hope that it is of interest for you...
They are all done with normal glass and glycerin... The Case is made in "Al" cutted by laser!
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
The video output result is quite good...
Here you can find my collection of information about Anamorfic Lens but I'm sorry is written in Italian (you can try the alatavista translator...)
http://www.realwc.com/anamorfico/anamorfico.htm
Cu
UbyOne
Curved mirror - again
Hi, there - my first post
I see that most of the lenses here are of the two-prism type. However i got a different idea inspired by the Sanyo PLV-Z2 brochure: http://www.sanyo-lcdp.com/english/pdf/plvz2-w.pdf
This lead me to post the following on the AVSforum:
"I am close to buying the infamous H30, but as i live in Denmark, I am a little concerned about its resolution being less than our PAL dvds. Buying an anamorphic lens could be a solution (if there is a problem at all). But I got an idea inspired by a picture from the Sanyo Z2 brochure, where the Z2 is wall-mounted and projecting vertically upwards into a mirror at a 45 degrees angle.
If this mirror was slightly curved (concave) so the reflected image would be squeezed vertically (ratio 1:1,3333..) the result would be similar to using an anamorphic lens. My preliminary CAD-sketches suggests that a curvature around 3.8 degrees could do the trick.
One of the difficulties would be to get hold of a flexible mirror material with a perfect surface, another to achieve the right curve for the mirror.
I will try to attach a visual sketch of this when I get it done.
Am I the first person to get this idea? - probably not - but I might try it out as a DIY project if I'm not put off by your comments.
Do you have an idea if it might work or not? Any ideas for mirror material?"
I see now that Amra describes a similar idea in post #313 so it is not new in that sense. But Slize answers him: "you will get in trouble with the sharpness of your projected picture. the curved mirror will bring parts of the picture out of focus so you will have blurred parts of the image... " I doubt that the blurriness will be significant, as a 3.8 degrees curved mirror of 100mm will prolong the trajectory of the central rays less than 2 mm.
Regards
Boye
Hi, there - my first post
I see that most of the lenses here are of the two-prism type. However i got a different idea inspired by the Sanyo PLV-Z2 brochure: http://www.sanyo-lcdp.com/english/pdf/plvz2-w.pdf
This lead me to post the following on the AVSforum:
"I am close to buying the infamous H30, but as i live in Denmark, I am a little concerned about its resolution being less than our PAL dvds. Buying an anamorphic lens could be a solution (if there is a problem at all). But I got an idea inspired by a picture from the Sanyo Z2 brochure, where the Z2 is wall-mounted and projecting vertically upwards into a mirror at a 45 degrees angle.
If this mirror was slightly curved (concave) so the reflected image would be squeezed vertically (ratio 1:1,3333..) the result would be similar to using an anamorphic lens. My preliminary CAD-sketches suggests that a curvature around 3.8 degrees could do the trick.
One of the difficulties would be to get hold of a flexible mirror material with a perfect surface, another to achieve the right curve for the mirror.
I will try to attach a visual sketch of this when I get it done.
Am I the first person to get this idea? - probably not - but I might try it out as a DIY project if I'm not put off by your comments.
Do you have an idea if it might work or not? Any ideas for mirror material?"
I see now that Amra describes a similar idea in post #313 so it is not new in that sense. But Slize answers him: "you will get in trouble with the sharpness of your projected picture. the curved mirror will bring parts of the picture out of focus so you will have blurred parts of the image... " I doubt that the blurriness will be significant, as a 3.8 degrees curved mirror of 100mm will prolong the trajectory of the central rays less than 2 mm.
Regards
Boye
Curved mirror "lens" update
Well, I've just learned, that the curved mirror will cause astigmatism because the horizontal and vertical image focus occur at different distances from the pj. My original simulation was based on the projector being a "point-source", but I do remember now, that any point on the screen is getting light from the entire front lens area..... Well I better try to go the the "two-prism" way.
Sorry for bothering you...
Regards
Boye
Well, I've just learned, that the curved mirror will cause astigmatism because the horizontal and vertical image focus occur at different distances from the pj. My original simulation was based on the projector being a "point-source", but I do remember now, that any point on the screen is getting light from the entire front lens area..... Well I better try to go the the "two-prism" way.
Sorry for bothering you...
Regards
Boye
Boye,
Don't give up on your idea so quickly, I wouldn't be surprised if the astigmatism was small enough to not be a problem and a lot a anamorphic lenses do not have any astigmatism correction. Besides mirrors have inhearantly less optical distortion than lenses.
The hardest part may be grinding a high quality cylindrical surface to have coated with a first surface mirror.
Also there is a way to correct for astigmatism but you need to use two mirrors.
You bounce the light off of two mirrors that are identically curved and slightly rotate them opposite each other on the image axis to correct for the astigmatism.
Hezz
Don't give up on your idea so quickly, I wouldn't be surprised if the astigmatism was small enough to not be a problem and a lot a anamorphic lenses do not have any astigmatism correction. Besides mirrors have inhearantly less optical distortion than lenses.
The hardest part may be grinding a high quality cylindrical surface to have coated with a first surface mirror.
Also there is a way to correct for astigmatism but you need to use two mirrors.
You bounce the light off of two mirrors that are identically curved and slightly rotate them opposite each other on the image axis to correct for the astigmatism.
Hezz
Hello Hezz
I think I will try to simulate how severe the astigmatism will be, before I go on.
The whole idea was to keep the construction very simple and easy to build. It doesn't have to be very complicated, before buying a pj with higher resolution would be more feasible, considering the time I would spend in the workshop and material cost. So using two mirrors sounds interesting but way over my level of ambition for this project.
My first idea was to use a metallized sheet of polycarbonate as a mirror and construct a simple wooden frame to bend it to the desired angle. The mirror should be a bit oversized. Then the amount of anamorphic "squeeze" could be adjusted by moving the mirror closer to or further away from the pj lens.
Boye
I think I will try to simulate how severe the astigmatism will be, before I go on.
The whole idea was to keep the construction very simple and easy to build. It doesn't have to be very complicated, before buying a pj with higher resolution would be more feasible, considering the time I would spend in the workshop and material cost. So using two mirrors sounds interesting but way over my level of ambition for this project.
My first idea was to use a metallized sheet of polycarbonate as a mirror and construct a simple wooden frame to bend it to the desired angle. The mirror should be a bit oversized. Then the amount of anamorphic "squeeze" could be adjusted by moving the mirror closer to or further away from the pj lens.
Boye
Boye,
I think your idea is worth trying out. You shoud be able to get a reasonably accurate surface by bending. It will come down to how well the mirrored surface takes it. They make acrylic sheets with mirror lamination on one side for signs. You can get it in a thickness that would be easy to bend like between 1 - 3mm.
Hezz
I think your idea is worth trying out. You shoud be able to get a reasonably accurate surface by bending. It will come down to how well the mirrored surface takes it. They make acrylic sheets with mirror lamination on one side for signs. You can get it in a thickness that would be easy to bend like between 1 - 3mm.
Hezz
Had the same idea.. Tried it a year ago with first surface plastic mirror. You really cant watch it. It get so distorted. I think it could work if you had a very short focus lens and tried to focus the picture on the mirror. if you have it at a very small angle (just to reflect the beam past the pj, i think it might work, but then tou´d need a second lens right?
1st Lens Curved mirror
PJ () \
()
image
1st Lens Curved mirror
PJ () \
()
image
I think this is what Boye is proposing to do, but with out the second lens, its not needed as the object is already focused.
As for the concave mirror, it might be easier to make a convex mirror and rotate it 90 degrees.
And as Hezz said, astigmatism shouldn't be too much of a problem, the small angle of 3.8 degrees isn't a great deal.
DJ
Guys,
I need to study this more but I was under the impression that astigmatism was a product of refraction differences in the two planes. Mirrors do not function like lenses because they do not refract the light image but only reflect it. This is a big difference. Therefore is seems to me that if you had a nearly perfect cylindrical mirrors it would have very little distortion. I also found that some of the offshoot anamorphic motion picture lenses used mirrors. It seems to me that the most elegant solution would be to put a slightly concave or convex mirror between the LCD and the objective lens in place of the regular flat mirror in designs that use a mirror like ACE's. In fact by using this method you could use two small cylindrical lenses just in front of the objective to correct for astigmatism if there was any. One lens is a negative and the other a positive. They are exactly alike except for being neg and pos.
When the lenses are aligned the net effect is zero but when they are retated axialy away from each other they will correct for any amount of astigmatism.
It may be that a parabolic mirror would work better but I think the curvature would be very small in either case.
A super high quality mirror can be hand made from glass blanks and then coated with a high quality first surface mirror finish. We just need some cheap experimental mirrors to ditermine the amount of curvature needed for a concave for vertical compression from 4:3 to 16:9 and for a convex for horizontal expansion from 4:3 to 16"9.
Hezz
I need to study this more but I was under the impression that astigmatism was a product of refraction differences in the two planes. Mirrors do not function like lenses because they do not refract the light image but only reflect it. This is a big difference. Therefore is seems to me that if you had a nearly perfect cylindrical mirrors it would have very little distortion. I also found that some of the offshoot anamorphic motion picture lenses used mirrors. It seems to me that the most elegant solution would be to put a slightly concave or convex mirror between the LCD and the objective lens in place of the regular flat mirror in designs that use a mirror like ACE's. In fact by using this method you could use two small cylindrical lenses just in front of the objective to correct for astigmatism if there was any. One lens is a negative and the other a positive. They are exactly alike except for being neg and pos.
When the lenses are aligned the net effect is zero but when they are retated axialy away from each other they will correct for any amount of astigmatism.
It may be that a parabolic mirror would work better but I think the curvature would be very small in either case.
A super high quality mirror can be hand made from glass blanks and then coated with a high quality first surface mirror finish. We just need some cheap experimental mirrors to ditermine the amount of curvature needed for a concave for vertical compression from 4:3 to 16:9 and for a convex for horizontal expansion from 4:3 to 16"9.
Hezz
Sorry I guess I was wrong about the astigmatism issues. However they can be resoved with the same method that they used for the first really good anamorphic motion picture lenses. Namely the astigmatism corrective lenses.
Hezz
Hezz
I found this thread seaching for a anamorphic lens.
Given its size i have not been able to read all of it 🙂
The DIY option has me interested as the commerical versions are expensive, especially once on ships to Australia with currency conversions etc 🙁
I have read mention of people using Lexan (Polycarb, Lexan is a brand of) with not the best results, obvously glass seems to be the best.
I work in the plastics fabrication industry (amoungst others) and deal with acrylic mainly. Acrlyic has better transparency properties than Polycarb, so i wonder if it is a viable option to make the prisms? This link indicates that the "mineral oil" that people have tried and seems to have "no attack" to acrylic
http://www.dynalabcorp.com/technical_info_acrylic.asp
At work we have a laser cutter, acrylic line benders, acrylic oven etc etc, so i can manfacture a pretty precise unit using these tools, and the skills of the fabricators (ie not me hehe 🙂)
Also acrylic can come in substantial thickness, though i don't know how good its transparency is at these greater thicknesses.
(it is transparent, but we haven't used it for these purposes 🙂)
Also of interest it can come in "matt black" also for sides and framing, using "all acrylic" makes it easier for bonding the complete unit together, and i gather matt black would help in reducing reflections.
If one things it will be "transparent" enuf to use, i will look at making a unit with acrylic, but as i have not read all this thread, perhaps people have tried an failed?
Given its size i have not been able to read all of it 🙂
The DIY option has me interested as the commerical versions are expensive, especially once on ships to Australia with currency conversions etc 🙁
I have read mention of people using Lexan (Polycarb, Lexan is a brand of) with not the best results, obvously glass seems to be the best.
I work in the plastics fabrication industry (amoungst others) and deal with acrylic mainly. Acrlyic has better transparency properties than Polycarb, so i wonder if it is a viable option to make the prisms? This link indicates that the "mineral oil" that people have tried and seems to have "no attack" to acrylic
http://www.dynalabcorp.com/technical_info_acrylic.asp
At work we have a laser cutter, acrylic line benders, acrylic oven etc etc, so i can manfacture a pretty precise unit using these tools, and the skills of the fabricators (ie not me hehe 🙂)
Also acrylic can come in substantial thickness, though i don't know how good its transparency is at these greater thicknesses.
(it is transparent, but we haven't used it for these purposes 🙂)
Also of interest it can come in "matt black" also for sides and framing, using "all acrylic" makes it easier for bonding the complete unit together, and i gather matt black would help in reducing reflections.
If one things it will be "transparent" enuf to use, i will look at making a unit with acrylic, but as i have not read all this thread, perhaps people have tried an failed?