desmondpun
Newly Enlightened
I probably can get somebody to make 30mm optics in glass or crystal. I wonder is it a better choice than plastic in terms of transparency, reflective index, heat standing... /ubbthreads/images/graemlins/help.gif
Glass 30mm optics
- Thread starter desmondpun
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PhotonBoy
Flashlight Enthusiast
I'm far from being an expert, but I'd be surprised if someone could make glass 30mm optics that would outperform the plastic 30mm lens on my Elektro Star. The precision and complexity of these optics amazes me.
Joe400
Newly Enlightened
Glass optics would indeed be sweet. If this is at all possible I would be interested in some, as Im sure a lot of other CPF members would be too. /ubbthreads/images/graemlins/thumbsup.gif
desmondpun
Newly Enlightened
I share the view of Photonboy that it's not easy to make. May be have a few sample done and send to Waynes for testing.
What I don't know about TIR is enough to probably keep me from saying anything here but heck, I won't let that stop me. I believe that the refractive index as well as critical angle of the material used will either qualify or disqualify the material as viable as an optic. As I understand it, the outside surface of the the optic is designed with a "pseudo" parabolic response in mind. That is to say that light from the LED will be reflected internally from this surface and exit in a close to parallel path with light hitting other areas of this surface.
In the optics I have looked at, the initial entrance surface to the optic is a straight walled tube. At the point of entrance, the light is initially bent as a function of the refractive index of the material. When the light contacts the outer surface of the optic, we want it to remain in the optic (angle of incidence > critical angle) and we want it to continue, exiting out of the front of the optic (angle of incidence < critical angle) with a final bend due to the index of refraction such that the light's final coarse is parallel to the axis of the optic.
If my understanding of the physics is even close here, I believe that the index of refraction of the material will dictate the shape of entrance, reflection and exit surfaces. Further, I suspect that there is likely only a certain range of refractive indices (sp) that would be viable. The Photon must first enter, then bounce and then exit. Point of entry will dictate point of bounce which then dictates point of exit. The photon's course is bent at points of entrance and exit as a function of the refractive index of the material. The photon will bounce internally with angle of incidence equal to angle of reflection provided that the angle of incidence is greater than the critical angle. If the angle of incidence is less than the critical angle, the photon will pass through the optic without bouncing.
With a great level of uncertainty I think what I have stated above is on track. With a great level of certainty, I state that optics are complicated! /ubbthreads/images/graemlins/grin.gif
- Don
BTW, I have pondered the flat exit surfaces of both the NX05 and the 30 mm. Now to me, flat is a "constant" curve. What happens if we alter that curve either by making it concave or convex? The NX01 which is favored by many has a complex exit surface.
In the optics I have looked at, the initial entrance surface to the optic is a straight walled tube. At the point of entrance, the light is initially bent as a function of the refractive index of the material. When the light contacts the outer surface of the optic, we want it to remain in the optic (angle of incidence > critical angle) and we want it to continue, exiting out of the front of the optic (angle of incidence < critical angle) with a final bend due to the index of refraction such that the light's final coarse is parallel to the axis of the optic.
If my understanding of the physics is even close here, I believe that the index of refraction of the material will dictate the shape of entrance, reflection and exit surfaces. Further, I suspect that there is likely only a certain range of refractive indices (sp) that would be viable. The Photon must first enter, then bounce and then exit. Point of entry will dictate point of bounce which then dictates point of exit. The photon's course is bent at points of entrance and exit as a function of the refractive index of the material. The photon will bounce internally with angle of incidence equal to angle of reflection provided that the angle of incidence is greater than the critical angle. If the angle of incidence is less than the critical angle, the photon will pass through the optic without bouncing.
With a great level of uncertainty I think what I have stated above is on track. With a great level of certainty, I state that optics are complicated! /ubbthreads/images/graemlins/grin.gif
- Don
BTW, I have pondered the flat exit surfaces of both the NX05 and the 30 mm. Now to me, flat is a "constant" curve. What happens if we alter that curve either by making it concave or convex? The NX01 which is favored by many has a complex exit surface.
shankus
Flashlight Enthusiast
*McGizmo* So, what you are saying, is that if it is manufactured from a different material in the same exact shape, that it may not work identcally to the plastic one, due to refractive differences in the material? (Even if the material has a better refractive index.)
And possibly, that the material for construction of the optic is of consideration when designing it, so choosing a different material may mean the designed shape might need to be altered?
And possibly, that the material for construction of the optic is of consideration when designing it, so choosing a different material may mean the designed shape might need to be altered?
Doug S
Flashlight Enthusiast
[ QUOTE ]
McGizmo said:
With a great level of uncertainty I think what I have stated above is on track. With a great level of certainty, I state that optics are complicated! /ubbthreads/images/graemlins/grin.gif
- Don
[/ QUOTE ]
Hey Don, It sounds to me that you *do* know what you are talking about. I say this with *some* certainty. One point, assuming that the index of refraction of the surrounding medium [air for our purposes] is unchanged, the critical angle is a function of the index of refraction of the material. Thus, if a glass and a plastic have the same index of refraction, the shape of the optic should be the same to obtain the same characteristics. With the existance of very good optical plastics which allow for injection molding, there isn't much reason for manufacturers to use glass for this [LED optics] application.
McGizmo said:
With a great level of uncertainty I think what I have stated above is on track. With a great level of certainty, I state that optics are complicated! /ubbthreads/images/graemlins/grin.gif
- Don
[/ QUOTE ]
Hey Don, It sounds to me that you *do* know what you are talking about. I say this with *some* certainty. One point, assuming that the index of refraction of the surrounding medium [air for our purposes] is unchanged, the critical angle is a function of the index of refraction of the material. Thus, if a glass and a plastic have the same index of refraction, the shape of the optic should be the same to obtain the same characteristics. With the existance of very good optical plastics which allow for injection molding, there isn't much reason for manufacturers to use glass for this [LED optics] application.
Doug S
Flashlight Enthusiast
[ QUOTE ]
shankus said:
*McGizmo* So, what you are saying, is that if it is manufactured from a different material in the same exact shape, that it may not work identcally to the plastic one, due to refractive differences in the material? (Even if the material has a better refractive index.)
And possibly, that the material for construction of the optic is of consideration when designing it, so choosing a different material may mean the designed shape might need to be altered?
[/ QUOTE ]
Shankus, I will presume to answer for Don. YES to both of your questions.
shankus said:
*McGizmo* So, what you are saying, is that if it is manufactured from a different material in the same exact shape, that it may not work identcally to the plastic one, due to refractive differences in the material? (Even if the material has a better refractive index.)
And possibly, that the material for construction of the optic is of consideration when designing it, so choosing a different material may mean the designed shape might need to be altered?
[/ QUOTE ]
Shankus, I will presume to answer for Don. YES to both of your questions.
shankus
Flashlight Enthusiast
[ QUOTE ]
Doug S said:
[ One point, assuming that the index of refraction of the surrounding medium [air for our purposes] is unchanged, the critical angle is a function of the index of refraction of the material. Thus, if a glass and a plastic have the same index of refraction, the shape of the optic should be the same to obtain the same characteristics.
[/ QUOTE ]
Oh, this seems very complex. Are you saying that if there were water outside the optic, or that if it were painted silver, the shape would have to be altered to get the same result?
Doug S said:
[ One point, assuming that the index of refraction of the surrounding medium [air for our purposes] is unchanged, the critical angle is a function of the index of refraction of the material. Thus, if a glass and a plastic have the same index of refraction, the shape of the optic should be the same to obtain the same characteristics.
[/ QUOTE ]
Oh, this seems very complex. Are you saying that if there were water outside the optic, or that if it were painted silver, the shape would have to be altered to get the same result?
shankus
Flashlight Enthusiast
Wow! That is fascinating, really.
So, if the best glass for optical transmission were used to fabricate an optic (assuming the shape of the optic is re-designed accordingly), would the result be a greatly improved optic? Or, would the increase in cost vs. the increase in performance not be worth the trouble?
So, if the best glass for optical transmission were used to fabricate an optic (assuming the shape of the optic is re-designed accordingly), would the result be a greatly improved optic? Or, would the increase in cost vs. the increase in performance not be worth the trouble?
Doug S
Flashlight Enthusiast
[ QUOTE ]
shankus said:
[ QUOTE ]
Doug S said:
[ One point, assuming that the index of refraction of the surrounding medium [air for our purposes] is unchanged, the critical angle is a function of the index of refraction of the material. Thus, if a glass and a plastic have the same index of refraction, the shape of the optic should be the same to obtain the same characteristics.
[/ QUOTE ]
Oh, this seems very complex. Are you saying that if there were water outside the optic, or that if it were painted silver, the shape would have to be altered to get the same result?
[/ QUOTE ]
Yes to the water question. This optic would function differently immersed in water. Silvering the outside would defeat the total internal reflection all together.
shankus said:
[ QUOTE ]
Doug S said:
[ One point, assuming that the index of refraction of the surrounding medium [air for our purposes] is unchanged, the critical angle is a function of the index of refraction of the material. Thus, if a glass and a plastic have the same index of refraction, the shape of the optic should be the same to obtain the same characteristics.
[/ QUOTE ]
Oh, this seems very complex. Are you saying that if there were water outside the optic, or that if it were painted silver, the shape would have to be altered to get the same result?
[/ QUOTE ]
Yes to the water question. This optic would function differently immersed in water. Silvering the outside would defeat the total internal reflection all together.
Doug S
Flashlight Enthusiast
[ QUOTE ]
shankus said:
Wow! That is fascinating, really.
So, if the best glass for optical transmission were used to fabricate an optic (assuming the shape of the optic is re-designed accordingly), would the result be a greatly improved optic? Or, would the increase in cost vs. the increase in performance not be worth the trouble?
[/ QUOTE ]
I doubt that any *significant* improvement could be had optically by using glass. Now if you needed an optic that would perform at 1000F, that would be another matter.
shankus said:
Wow! That is fascinating, really.
So, if the best glass for optical transmission were used to fabricate an optic (assuming the shape of the optic is re-designed accordingly), would the result be a greatly improved optic? Or, would the increase in cost vs. the increase in performance not be worth the trouble?
[/ QUOTE ]
I doubt that any *significant* improvement could be had optically by using glass. Now if you needed an optic that would perform at 1000F, that would be another matter.
Well,
Given my limited understanding, I agree with all that Doug has stated. IFF the index of refraction for two optic materials are the same, then the same form of optic would have the same effect regardless of material. If the index of refraction is different, the geometry of the optic will need to be different to redirect the light the same for both materials.
Shankus, air and water have different indices of refraction so there would be a different effect. If you go snorkeling with a face mask, objects appear to be larger and closer underwater because of this. If you look at a straight pillar going into still water, depending on your point of reference, the pillar can appear to bend at the water surface and continue under water at a different angle.
I believe there is some glass that is used with fiber optics but suspect that the material of preference is specific plastics. I suspect that a "normal" glass lens shaped like say a NX05 would result with most of the light passing right through the optic; bent and out the side as opposed to bouncing internally on the side and then exiting the front.
I think it is important to bear in mind that the advantage to an optic over a reflector is that it will alter the path of all of the light generated whereas the reflector only redirects the light that contacts it. The deeper the reflector, the greater the sum total of light that is redirected. If you look at the SF 5W reflectors, they are very deep relative to their diameter. The side emitter as well as batwing provide more off angle light that is easier to catch and re direct with a reflector. With a lambertian distribution, a significant amount of light escapes a reflector without any contact.
In the comments I have made so far, i have ignored the ball portion of the existing optics and yet this a key element in overall light management and really complicates the *real* picture of what is going on.
- Don
Given my limited understanding, I agree with all that Doug has stated. IFF the index of refraction for two optic materials are the same, then the same form of optic would have the same effect regardless of material. If the index of refraction is different, the geometry of the optic will need to be different to redirect the light the same for both materials.
Shankus, air and water have different indices of refraction so there would be a different effect. If you go snorkeling with a face mask, objects appear to be larger and closer underwater because of this. If you look at a straight pillar going into still water, depending on your point of reference, the pillar can appear to bend at the water surface and continue under water at a different angle.
I believe there is some glass that is used with fiber optics but suspect that the material of preference is specific plastics. I suspect that a "normal" glass lens shaped like say a NX05 would result with most of the light passing right through the optic; bent and out the side as opposed to bouncing internally on the side and then exiting the front.
I think it is important to bear in mind that the advantage to an optic over a reflector is that it will alter the path of all of the light generated whereas the reflector only redirects the light that contacts it. The deeper the reflector, the greater the sum total of light that is redirected. If you look at the SF 5W reflectors, they are very deep relative to their diameter. The side emitter as well as batwing provide more off angle light that is easier to catch and re direct with a reflector. With a lambertian distribution, a significant amount of light escapes a reflector without any contact.
In the comments I have made so far, i have ignored the ball portion of the existing optics and yet this a key element in overall light management and really complicates the *real* picture of what is going on.
- Don
Dang! just lost a post being composed! Don't you hate that!
Doug,
I thought that light contacting the boundary layer of a medium would either reflect or pass depending on the refractive index and hence critical angle of the medium the light was currently in. Your statements imply that the critical angle is a result or based on both mediums present at the boundary layer?
Another monkey wrench to throw in to the optics solutions is the fact that different wavelengths of light have slightly different indices of refraction as I recall. A red and blue LED in a reflectored setting will behave in a similar manner but I believe that a red and blue light source in an optic lens setting will behave slightly different??
- Don
Doug,
I thought that light contacting the boundary layer of a medium would either reflect or pass depending on the refractive index and hence critical angle of the medium the light was currently in. Your statements imply that the critical angle is a result or based on both mediums present at the boundary layer?
Another monkey wrench to throw in to the optics solutions is the fact that different wavelengths of light have slightly different indices of refraction as I recall. A red and blue LED in a reflectored setting will behave in a similar manner but I believe that a red and blue light source in an optic lens setting will behave slightly different??
- Don
Doug S
Flashlight Enthusiast
[ QUOTE ]
McGizmo said:
Doug,
I thought that light contacting the boundary layer of a medium would either reflect or pass depending on the refractive index and hence critical angle of the medium the light was currently in. Your statements imply that the critical angle is a result or based on both mediums present at the boundary layer?
- Don
[/ QUOTE ]
Right, critical angle depends on both mediums. The greater the difference in the two indices, the stronger the effect. In the limiting case where the two indices are equal, no refraction or critical angle reflection will occur. As a mind exercise, visualize an imaginary plane in air, no reflection or refraction occurs at this plane because the indices of refraction on both sides are equal.
[ QUOTE ]
McGizmo said:
Another monkey wrench to throw in to the optics solutions is the fact that different wavelengths of light have slightly different indices of refraction as I recall. A red and blue LED in a reflectored setting will behave in a similar manner but I believe that a red and blue light source in an optic lens setting will behave slightly different??
- Don
[/ QUOTE ]
Right you are. This is the basis for spliting white light by prisms, water droplets, etc.
McGizmo said:
Doug,
I thought that light contacting the boundary layer of a medium would either reflect or pass depending on the refractive index and hence critical angle of the medium the light was currently in. Your statements imply that the critical angle is a result or based on both mediums present at the boundary layer?
- Don
[/ QUOTE ]
Right, critical angle depends on both mediums. The greater the difference in the two indices, the stronger the effect. In the limiting case where the two indices are equal, no refraction or critical angle reflection will occur. As a mind exercise, visualize an imaginary plane in air, no reflection or refraction occurs at this plane because the indices of refraction on both sides are equal.
[ QUOTE ]
McGizmo said:
Another monkey wrench to throw in to the optics solutions is the fact that different wavelengths of light have slightly different indices of refraction as I recall. A red and blue LED in a reflectored setting will behave in a similar manner but I believe that a red and blue light source in an optic lens setting will behave slightly different??
- Don
[/ QUOTE ]
Right you are. This is the basis for spliting white light by prisms, water droplets, etc.
sidespill
Enlightened
i'm not pretending to know what you guys understand about the science of optics but i just had a question. the 30mm optics really seems to sqeeze almost every little bit out of a 1w. is a 5w a bigger version of a 1w? if so would it be possible to make a optic in proportion to the 5w? meaning a 30mm optic on a larger scale to mimic the 1w with 30mm optic.
IsaacHayes
Flashlight Enthusiast
Yeah, wavelength does matter with optics. As Wayne said once to me that the 30mm optics does very poorly with Red luxeons.
Thanks Doug,
Some of it is coming back to me. /ubbthreads/images/graemlins/grin.gif High School physics was over 30 years ago...
redloviar353,
A larger diameter optic lens would aid the 5W just as a larger reflector does. In either case, that larger the optic is relative to the light source's objective size, the more efficient it will be on directing the light in a more uniform fashion. A focal point is still just a focal point but the acceptable "sweet spot" assosiated with the focal point grows with the size of the optic (lens or reflector). I am sure I have done a serious injustice here with my explaination but I hope you can unserstand what I mean.
I think just comparing the 30 mm to the NX05 shows the value of a larger sized optic as does comparing the reflector of a full size mag compared to the reflector of the mini mag.
- Don
Some of it is coming back to me. /ubbthreads/images/graemlins/grin.gif High School physics was over 30 years ago...
redloviar353,
A larger diameter optic lens would aid the 5W just as a larger reflector does. In either case, that larger the optic is relative to the light source's objective size, the more efficient it will be on directing the light in a more uniform fashion. A focal point is still just a focal point but the acceptable "sweet spot" assosiated with the focal point grows with the size of the optic (lens or reflector). I am sure I have done a serious injustice here with my explaination but I hope you can unserstand what I mean.
I think just comparing the 30 mm to the NX05 shows the value of a larger sized optic as does comparing the reflector of a full size mag compared to the reflector of the mini mag.
- Don
shankus
Flashlight Enthusiast
[ QUOTE ]
McGizmo said:
i have ignored the ball portion of the existing optics and yet this a key element in overall light management and really complicates the *real* picture of what is going on.
[/ QUOTE ]
That is another portion of the optic I was wondering about. That form is so bizarre to me. A diagram of the angles the photons travel to exit the objective side of the optic would be most interesting, I would think.
Does the 30 mm optic follow a similar form? And what is the other one I see mentioned recently? (The fraen, if I remember correctly.)
McGizmo said:
i have ignored the ball portion of the existing optics and yet this a key element in overall light management and really complicates the *real* picture of what is going on.
[/ QUOTE ]
That is another portion of the optic I was wondering about. That form is so bizarre to me. A diagram of the angles the photons travel to exit the objective side of the optic would be most interesting, I would think.
Does the 30 mm optic follow a similar form? And what is the other one I see mentioned recently? (The fraen, if I remember correctly.)
whiskypapa3
Enlightened
desmondpun
Aside from the technical issues above consider the practical one. Back in the good old days before my eyes went bad I faceted a deep bellied stone about 30mm in dia. The pavillion (pointy end) had over 400 facets much like some of the better reflectors have. To work at all a glass optic would have to be as well polished as the stone. It took close to 20 hours to do it. I still do consulting for a couple of crystalware restorers who now charge about $65-$90 an hour for polishing services or what a commercial facetor would charge. Looks like about $1500 a pop.
$1500 for a mold master isn't to bad but for an EDC?
Aside from the technical issues above consider the practical one. Back in the good old days before my eyes went bad I faceted a deep bellied stone about 30mm in dia. The pavillion (pointy end) had over 400 facets much like some of the better reflectors have. To work at all a glass optic would have to be as well polished as the stone. It took close to 20 hours to do it. I still do consulting for a couple of crystalware restorers who now charge about $65-$90 an hour for polishing services or what a commercial facetor would charge. Looks like about $1500 a pop.
$1500 for a mold master isn't to bad but for an EDC?
