Diffraction gratings for laser pointer
Mark Fergerson
>
> Diffraction gratings as extension piece to laser pointer
$9.00 at your local Walgreen's drugstore (includes pointer &
batteries).
> plus CD-ROM with theory and visualizations.
Isn't that what textbooks are for?
Mark L. Fergerson
Andrey Titov
>
> $9.00 at your local Walgreen's drugstore (includes pointer &
> batteries).
For physics experiments?
> > plus CD-ROM with theory and visualizations.
>
> Isn't that what textbooks are for?
Theory of diffraction of light.
Mark Fergerson
>
> > > Diffraction gratings as extension piece to laser pointer
> >
> > $9.00 at your local Walgreen's drugstore (includes pointer &
> > batteries).
>
> For physics experiments?
Why not? The set I was given last Father's Day included one that
produces a very neat straight line, another that yields an arrow.
Useful with (free AOL) CD's, lenses, prisms, and so on. Also fun with
water. You gotta set it up carefully for collinearity/concentricity,
but so what? Gotta get the grandkids interested in something besides
Pokemon somehow. When they get bored, they can annoy/amuse the dogs
and cats.
> > > plus CD-ROM with theory and visualizations.
> >
> > Isn't that what textbooks are for?
>
> Theory of diffraction of light.
My point exactly. By the time the grandkids see the textbooks,
they'll be ahead of the rest of the class.
Mark L. Fergerson
Michael H Stevens
laszer for $10.00 US shipping paid.
Mike
"Mark Fergerson" <mferg...@home.com> wrote in message
news:394708BA...@home.com...
Future Beacon
Can anybody refer me to an expert in designing lens systems using
only reflectors?
My previous questions to sci.optics seems to have generated a number
of issues that I didn't anticipate. I am interested in knowing
whether a lens system composed exclusively of reflectors could be
capable of doing all of the common imaging tasks that refractors
can do with monochromatic light. I am not interested in cost or
compactness comparisons or minimizing the number of surfaces or
obscuration problems unless they absolutely prevent some particular
kind of job to be done.
Thank you for your help.
Jim Trek
Future Beacon Technology
http://eznet.net/~progress
prog...@eznet.net
Lou Boyd
> Can anybody refer me to an expert in designing lens systems using
> only reflectors?
If it used only reflectors it wouldn't be a lens system. It would be a
mirror system.
> My previous questions to sci.optics seems to have generated a number
> of issues that I didn't anticipate. I am interested in knowing
> whether a lens system composed exclusively of reflectors could be
> capable of doing all of the common imaging tasks that refractors
> can do with monochromatic light. I am not interested in cost or
> compactness comparisons or minimizing the number of surfaces or
> obscuration problems unless they absolutely prevent some particular
> kind of job to be done.
It's immediately obvious that a system using reflectors cannot generally
duplicate a lens system. It
might be possible to come close to similar performance to SOME lens
systems using mirrors.
Take the simple example of a single plano-convex lens forming an image
of a distant object behind the lens. A few moments of though should
convince you that there is no mirror system which will place the same
image in the same location with the same scale, same field size, and
same symetrical axis using mirrors. It can't be done. Certainly
mirrors make very useful optical systems, but they are seldom used as
direct replacements for lenses.
If you stated what you are trying to achieve you might get better
responses.
--
Lou Boyd
-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 80,000 Newsgroups - 16 Different Servers! =-----
Richh
Lou Boyd wrote:
> Future Beacon wrote:
>
> > Can anybody refer me to an expert in designing lens systems using
> > only reflectors?
>
> If it used only reflectors it wouldn't be a lens system. It would be a
> mirror system.
>
> > My previous questions to sci.optics seems to have generated a number
> > of issues that I didn't anticipate. I am interested in knowing
> > whether a lens system composed exclusively of reflectors could be
> > capable of doing all of the common imaging tasks that refractors
> > can do with monochromatic light. I am not interested in cost or
> > compactness comparisons or minimizing the number of surfaces or
> > obscuration problems unless they absolutely prevent some particular
> > kind of job to be done.
>
> It's immediately obvious that a system using reflectors cannot generally
> duplicate a lens system. It
> might be possible to come close to similar performance to SOME lens
> systems using mirrors.
>
> Take the simple example of a single plano-convex lens forming an image
> of a distant object behind the lens. A few moments of though should
> convince you that there is no mirror system which will place the same
> image in the same location with the same scale, same field size, and
> same symetrical axis using mirrors. It can't be done.
Gee, that would require two reflectors, probably one with a hole through the
center to project the image through, and unfortunately, would not spread the
spectrum to exhibit the red and blue fuzzies that simple plano convex lenses
do so well. Also, a 2 reflector system would not produce the inverted image
of a single lens at focus.
Has any work been done on microscopy by way of reflectors? The lens
corrections and number of lenses needed might make the use of reflectors a
substantial benefit.
> Certainly
> mirrors make very useful optical systems, but they are seldom used as
> direct replacements for lenses.
>
> If you stated what you are trying to achieve you might get better
> responses.
> --
> Lou Boyd
>
> -----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
> http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
> -----== Over 80,000 Newsgroups - 16 Different Servers! =-----
richh
Future Beacon
On Sat, 12 Aug 2000, Lou Boyd wrote:
> Future Beacon wrote:
>
> > Can anybody refer me to an expert in designing lens systems using
> > only reflectors?
>
> If it used only reflectors it wouldn't be a lens system. It would be a
> mirror system.
Lou,
Academia sometimes names things so badly that one couldn't
sell food to the hungry.
I hereby name these things lenses. They may also be called
reflective lenses, or reflectors (in the context of lenses).
The lens systems may be called reflective lens systems or
reflector systems. Any marketing person publicly calling them
mirrors will be subjected to a four minute reading of my poetry.
I know this is harsh, but it's for your own good.
If I make 'em, I get to name 'em. I wouldn't sell mirrors any
sooner than I would sell pearl-handled revolvers.
I hope that helps.
R. Andrew Hicks
achieved. for example i have designed ultra wide angle sensors with them.
see my webpage
http://www.cis.upenn.edu/~rah/mirrors.html
Andy Hicks
ahi...@drexel.edu
Lou Boyd wrote:
> Future Beacon wrote:
>
>
>
> If it used only reflectors it wouldn't be a lens system. It would be a
> mirror system.
>
>
>
> It's immediately obvious that a system using reflectors cannot generally
> duplicate a lens system. It
> might be possible to come close to similar performance to SOME lens
> systems using mirrors.
>
>
>
Mark Folsom
my Minolta camera. I have a 2000 mm f10 Schmidt-Cassegrain astronomical
telescope. What do you want to do with mirrors?
Mark Folsom
"Future Beacon" <prog...@eznet.net> wrote in message
news:Pine.LNX.4.21L2.00081...@shell1.eznet.net...
>
>
>
> On Sat, 12 Aug 2000, Lou Boyd wrote:
>
> > Future Beacon wrote:
> >
> > > Can anybody refer me to an expert in designing lens systems using
> > > only reflectors?
> >
> > If it used only reflectors it wouldn't be a lens system. It would be a
> > mirror system.
>
>
Bob May
that you have to be able to talk to others and if you don't have a
standard set of words, you will never be able to talk to the other
person. Go listen to Ebonics (yep, it's english words but not english
meanings for those words) for a bit and you will see what I mean. You
need to translate what the words (english words to english words) mean
in order to be able to understand what is being said. For a very good
reference work on what happens when this sort of thing goes wild, go
read about the Tower of Babel in the bible - it tells you exactly what
happens when you allow for any word to mean anything you want it to.
The fact of the matter, there are things that you can't do easily with
reflectors that you can do with refractors and vice versa.
--
Bob May
Access1 has gone Chapter 7 so I don't know how long my website is
going to last.
Bob May
Lou Boyd
trouble finding suppliers. My money went to companies which advertised
that they manufactured mirrors, not lens systems.
I hope that helps.
I haven't bought any pearl-handled revolvers either. Ivory and walnut,
yes, but not pearl.
--
Lou Boyd
On Sat, 12 Aug 2000, Lou Boyd wrote:
> Future Beacon wrote:
>
> > Can anybody refer me to an expert in designing lens systems using
> > only reflectors?
>
> If it used only reflectors it wouldn't be a lens system. It would be a
> mirror system.
Lou,
Academia sometimes names things so badly that one couldn't
sell food to the hungry.
I hereby name these things lenses. They may also be called
reflective lenses, or reflectors (in the context of lenses).
The lens systems may be called reflective lens systems or
reflector systems. Any marketing person publicly calling them
mirrors will be subjected to a four minute reading of my poetry.
I know this is harsh, but it's for your own good.
If I make 'em, I get to name 'em. I wouldn't sell mirrors any
sooner than I would sell pearl-handled revolvers.
I hope that helps.
Future Beacon
On Sat, 12 Aug 2000, R. Andrew Hicks wrote:
> that is false.
When an author makes up a term and journals use it in their indexes,
that term is just fine until you have to advertise it on TV. Then,
you have to listen to your customers.
--------------
Mark Folsom wrote:
> There are lots of "mirror lenses"---I have a 500 mm f8 mirror lens
> that fits my Minolta camera.
Even this term could disqualify you as a genuine scholar if it were
not for the definition of August 12, 2000 which gives the public
permission to call these things lenses without feeling bad.
--------------
Lou Boyd wrote:
> Last year I spent about $200K on mirrors. Maybe that's why I had
> trouble finding suppliers. My money went to companies which
> advertised that they manufactured mirrors, not lens systems.
> I hope that helps.
>
> I haven't bought any pearl-handled revolvers either. Ivory and
> walnut, yes, but not pearl.
Thank you for your evidence, Lou.
--------------
Bob May wrote:
> Tsk, tsk. You can call them what you want to but you have to
> remember that you have to be able to talk to others and if you
> don't have a standard set of words, you will never be able to talk
> to the other person. Go listen to Ebonics (yep, it's English
> words but not English meanings for those words) for a bit and you
> will see what I mean. You need to translate what the words
> (English words to English words) mean in order to be able to
> understand what is being said. For a very good reference work on
> what happens when this sort of thing goes wild, go read about the
> Tower of Babel in the bible - it tells you exactly what happens
> when you allow for any word to mean anything you want it to.
Terms have been changed badly and well. In this case, if you don't
let the customer call these things lenses and reflecting or reflective
lenses at that, sales will suffer. All of your innovations are at
risk of making no impact if you can't send a signal to the customer's
brain. They will call them lenses. They will claim that they reflect
light. You can cross-reference that to mirrors if you want to.
> The fact of the matter, there are things that you can't do easily
> with reflectors that you can do with refractors and vice versa.
Now THAT is interesting.
Future Beacon
On Sat, 12 Aug 2000, Mark Folsom wrote:
> What do you want to do with mirrors?
Mark,
As you may have heard, I will be marketing them as lenses
(reflecting though they are).
The depth of field needs to be a great as possible. In some
robotics applications it is very desirable to eliminate the
need for adjusting the focus (if that can be done). If the lens
system can be in focus from a few feet out to infinity, then
the hight of the robotic mechanism can be used to provide a path
that is a few feet long before a reflector changes the direction
form vertical to horizontal. If the shortest focal length is
a few inches, then there is no need to bend the viewing 90
degrees.
If this can be achieved while providing a 180 degree viewing
angle centered on the zenith, all the better; but at least a
20 degree viewing angle is needed in a horizontal aiming
configuration.
Reflective lens CAD software would be nice to have. If you can
make the design considerations clear enough, I can design software
and have it written. I would have no interest in refracting lenses
unless I found a robotic application that could not be done without
them. That seems unlikely.
Mark Folsom
>
>
>
> On Sat, 12 Aug 2000, Mark Folsom wrote:
>
> > What do you want to do with mirrors?
>
>
> Mark,
>
> As you may have heard, I will be marketing them as lenses
> (reflecting though they are).
>
> The depth of field needs to be a great as possible.
Depth of field is largely a function of focal ratio = (focal length)/(lens
aperture), since the divergence angle of rays converging at a point in the
image plane is approximately the aperture diameter divided by the focal
length. High focal ratios tend to necessitate long exposure times/sensitive
sensor chips/bright light.
> In some
> robotics applications it is very desirable to eliminate the
> need for adjusting the focus (if that can be done).
How fuzzy an image is good enough?
> If the lens
> system can be in focus from a few feet out to infinity, then
> the hight of the robotic mechanism can be used to provide a path
> that is a few feet long before a reflector changes the direction
> form vertical to horizontal. If the shortest focal length is
> a few inches, then there is no need to bend the viewing 90
> degrees.
What's the range of viewing distances you need to cover with a particular
imaging system?
>
> If this can be achieved while providing a 180 degree viewing
> angle centered on the zenith, all the better; but at least a
> 20 degree viewing angle is needed in a horizontal aiming
> configuration.
The image size is about (twice the tangent of half the viewing angle) * (the
distance from the image plane to the lens). Pick a chip, pick a view
angle... out comes focal length.
>
> Reflective lens CAD software would be nice to have. If you can
> make the design considerations clear enough, I can design software
> and have it written.
You can download OSLO 5 LT (a limited version of their software) for free
from their website. I haven't done a lot of mirrors with it, but I've seen
examples where others have.
> I would have no interest in refracting lenses
> unless I found a robotic application that could not be done without
> them.
What do you have against refraction?
> That seems unlikely.
>
Mark Folsom
jaca...@my-deja.com
Sorry, ;-) for the regressive allusion to vintage TV...
I always get amused when people go to such lengths to defend their
particular notation and vernacular. "Reflective lens system" IS an
entirely appropriate description of a reflecting mirror optical layout
that forms a real or virtual image.
In order to talk to others, all I need is to be able to adequately
describe my thoughts. Relying too heavily on jargon only limits my
thought processes and leads to misconceptions based on the other's
pre-conceived definitions. Perhaps that's the advantage that German
engineers have had using their own native tongue: you can create
new terms by concatenating simple, descriptive terms...
Regarding Jim's original query: there are many that would claim to
be experienced in reflective optical design. Their skills range from
the sublime to the ridiculous. Many of the simpler, symmetrical forms
exist in patent databases and anybody with Zemax can probably
tailor these to a specific application. For more complex, and notably
off-axis, designs, real experience is difficult to find. If you need
only advice, then you may wish to hit the library. If you need a
consultant, I know of a very good and experienced one that may be
interested. I won't presume to commit his time or name until I
am sure that both parties are interested and serious.
If this is the case, please contact me at jaca...@my-deja.com
Best regards,
James Carter
In article <3996FCDF...@fairborn.dakotacom.net>,
Lou Boyd <bo...@fairborn.dakotacom.net> wrote:
> Last year I spent about $200K on mirrors. Maybe that's why I had
> trouble finding suppliers. My money went to companies which
advertised
> that they manufactured mirrors, not lens systems.
> I hope that helps.
>
> I haven't bought any pearl-handled revolvers either. Ivory and
walnut,
> yes, but not pearl.
> --
> Lou Boyd
>
> On Sat, 12 Aug 2000, Lou Boyd wrote:
>
> > Future Beacon wrote:
> >
> > > Can anybody refer me to an expert in designing lens systems using
> > > only reflectors?
> >
> > If it used only reflectors it wouldn't be a lens system. It would be
a
> > mirror system.
>
> Lou,
>
> Academia sometimes names things so badly that one couldn't
> sell food to the hungry.
>
> I hereby name these things lenses. They may also be called
> reflective lenses, or reflectors (in the context of lenses).
> The lens systems may be called reflective lens systems or
> reflector systems. Any marketing person publicly calling them
> mirrors will be subjected to a four minute reading of my poetry.
> I know this is harsh, but it's for your own good.
>
> If I make 'em, I get to name 'em. I wouldn't sell mirrors any
> sooner than I would sell pearl-handled revolvers.
>
> I hope that helps.
>
> -----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
> http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
> -----== Over 80,000 Newsgroups - 16 Different Servers! =-----
>
Sent via Deja.com http://www.deja.com/
Before you buy.