Omid's innovation (split from 'new Leica binocular' thread) (1 Viewer)

Omid · Aug 15, 2016

ronh said:
Hi Omid,

Forgive me for not having read your patent, but I recall from some previous discussion that part of your invention involves projection of the image onto a screen, which can then be viewed from any distance or angle. Of course the optics before and after that screen leave plenty of room for creativity! But could you say, if this screen projection is the brightness and resolution limitation that you mention?

We are mostly here familiar with cameras that project the image onto ground glass for composition and focusing--would it be something like that, as far as image "vividness" goes?

Ron

Hello Ron,

Yes, your recollection is correct. The concept is to use a special screen or "device" (not a focusing screen, although that technically works too) positioned at the common focal plane of the objective/eyepiece to expand the diameter of the light cone emitted towards the eyepiece. This will expand the exit pupil and will also alter its position. So, both eye relief and exit pupil diameter are affected. If the exit pupil is expanded sufficiently, then the eye relief becomes uncritical.

You can observe this effect in your own SLR camera. If you look through the view finder of an SLR camera, you will notice that it does not have a critical "eye point" as binoculars and spotting scopes do. The light beam coming out of the view finder is as large as the viewfinder lens area and does not shrink into a small beam if you move your head back.

Here is a video clip that shows the concept of exit pupil expansion demonstrated in binoculars:

https://vimeo.com/178946233

The left barrel has been modified to have expanded exit pupil. The right barrel is conventional (its exit pupil is briefly visible at some point later in the video).

PS. I forgot to say this: I highly appreciate that the BF admins decided to carve out my posts from the original thread and created a dedicated thread for it. I look forward to constructive discussions of this concept and welcome critiquing it as well. As any new idea, it might turn out that there are some technical or practical reasons that make it not viable but lets all think about this and see if it actually has merit. Thank you.

Omid · Aug 15, 2016

jan van daalen said:
Hi Omid,

The topic of the thread has changed.
Taking the risk it will be moved again:
About what kind of super large field of view eyepiece are you aware of?

Hi Jan,

Well, I can not speak in detail but I can mention that it is related to having a binoculars with very large field of view but without the ergonomic problems that are caused if you tried to put two existing wide-field eyepieces next to each other. [edited by Omid]

Binastro · Aug 15, 2016

Maybe a reverse Galilean viewfinder arrangement?
Not sure if my compact camera has a 6x zoom version.
The problem with this is precise parallelism with lens axis is difficult to achieve and is skilled labour intensive.
So on digital zoom what you see is not what you get. Only one camera in about six has an accurate viewfinder that can deal with 6x zoom and digital 4x, giving 24x.
When you get to 20x, 30x and 65x optical zoom lenses optical viewfinders are out, although some have dot finders. Camera makers want everything made by machine, which is why viewfinders were phased out, only to be phased back in with electronic viewfinders.
I hate cameras without viewfinders.

P.S.
So the camera makers fudge the issue by having the viewfinder only covering 75% of the sensor area.
This means that the view you see through the viewfinder will be somewhere within the sensor edges, despite the two axes not being parallel. They may claim it is to deal with parallax, but this a minor part of the issue.
However, if you use the viewfinder with full 24x digital zoom, you are likely not to get what you are looking at with most of these cameras.

etudiant · Aug 16, 2016

Binastro said:
I hate cameras without viewfinders.

P.S.
So the camera makers fudge the issue by having the viewfinder only covering 75% of the sensor area.
This means that the view you see through the viewfinder will be somewhere within the sensor edges, despite the two axes not being parallel. They may claim it is to deal with parallax, but this a minor part of the issue.
However, if you use the viewfinder with full 24x digital zoom, you are likely not to get what you are looking at with most of these cameras.

On a scope, these parallelism issues would not arise. Better eye relief would be compelling if the optical sacrifice is not too great.
Binoculars may be a harder problem if existing tolerances are not tight enough.

Omid · Aug 16, 2016

Binastro said:
Maybe a reverse Galilean viewfinder arrangement?
Not sure if my compact camera has a 6x zoom version.
The problem with this is precise parallelism with lens axis is difficult to achieve and is skilled labour intensive...

I am not sure if I understood your point. Are you talking about how one can enlarge the exit pupil and/or make a telescope without a specific eye-relief?

In a Galilean telescope, the exit pupil diameter is the same as a comparable Keplerian telescope (i.e. Objective Diameter/Magnification). The difference is it is located inside the telescope so you can not position your eye there.

My method does not apply to a Galilean telescope. It requires an intermediate image plane which a Galilean telescope does not have.

I put a link to a video in my Post # 21 above. It shows the effect very clearly.

Binastro · Aug 16, 2016

Hi Omid,
No, I think that camera optical viewfinders are mostly of two types.
A common one is a reversed Galilean, i.e. You are looking through it backwards, with a magnification of less than one.
Sorry, I didn't yet look at your video, as this old computer doesn't show some.

There is an interesting discussion by Fuji relating to a new XT2 ?? viewfinder.

Binastro · Aug 16, 2016

Thanks Omid,
I did manage to see your video and see what you mean.
It did mess up the computer, but I managed to reboot, and now it is O.K.
I don't know why this happens.
But normally I avoid videos.

ronh · Aug 17, 2016

Omid,

I too have difficulty with the video. Could you provide a link to the patent?

Ron

Binastro · Aug 17, 2016

Hi Omid.
I just looked through a 2.0x16 Galilean focusing binocular backwards.
There is no exit pupil and the image is physically large in diameter.
You can view at a considerable distance, but the field narrows from 45 degree real as you get further away.

I thought that you used a 42mm binocular with 9mm focus 82 degree EWA eyepieces and a reversed Galilean 2.2x finder optic giving 0.45x, resulting in an 8x42 binocular.

I did not know how you did it or whether the 82 degree AFOV was maintained.

Omid · Aug 17, 2016

@Binastro: Yes, if you look through a Galilean viewfinder in reverse then you will observe that it is very easy to see the image even if you look from the sides or from a distance for the view finder. This is because the exist pupil of such a view finder is naturally large (=diameter of the objective lens). You will notice the same thing if you look through the objective side of a pair of binoculars (say 8X42) too! It is very easy to view the image and there is no ``eye relief''.

The above phenomena have been well known. A Galilean viewfinder and a revered binocular are both "minifying" instruments. It is also possible to get a very large exit pupil if you make the objective lens very large or you lower the magnification (note: exit pupil diameter = objective diameter / magnification). So, if you make a 6X120 binoculars, they will have huge exit pupils (20mm wide) and it would be very easy to look through them. These phenomena are not what we are talking about here.

What we are discussing is a normal (not reversed) Keplerian telescope or binoculars with normal magnification (say 10x) and normal objective diameter (say 50mm) but having an exit pupil far larger than 5mm and further having no critical eye relief. That's the result of my invention.

Regarding the video clip, I am not sure what the problem is/was. Maybe we change the https to http in the link it will work better:

http://vimeo.com/178946233

@Ronh: Here is my core patent on this innovation (more are pending): https://www.google.com/patents/US8749884

elkcub · Aug 17, 2016

Omid said:
@Binastro: Yes, if you look through a Galilean viewfinder in reverse then you will observe that it is very easy to see the image even if you look from the sides or from a distance for the view finder. This is because the exist pupil of such a view finder is naturally large (=diameter of the objective lens). You will notice the same thing if you look through the objective side of a pair of binoculars (say 8X42) too! It is very easy to view the image and there is no ``eye relief''.

The above phenomena have been well known. A Galilean viewfinder and a revered binocular are both "minifying" instruments. It is also possible to get a very large exit pupil if you make the objective lens very large or you lower the magnification (note: exit pupil diameter = objective diameter / magnification). So, if you make a 6X120 binoculars, they will have huge exit pupils (20mm wide) and it would be very easy to look through them. These phenomena are not what we are talking about here.

What we are discussing is a normal (not reversed) Keplerian telescope or binoculars with normal magnification (say 10x) and normal objective diameter (say 50mm) but having an exit pupil far larger than 5mm and further having no critical eye relief. That's the result of my invention.

Regarding the video clip, I am not sure what the problem is/was. Maybe we change the https to http in the link it will work better:

http://vimeo.com/178946233

@Ronh: Here is my core patent on this innovation (more are pending): https://www.google.com/patents/US8749884

Omid,

I'm having difficulty understanding this. Referring to your patent, which configuration(s) apply to a riflescope vs. a binocular? Which one was incorporated into your (binocular) video demonstration above?

A conventional telescope is afocal (when set to infinity), and the exit pupil is located a finite distance from the eye lens (which is the eye relief). The output image is located at infinity, so the eye is necessary to focus it on the retina.

Would your binocular application also be afocal, and rely on the eye to focus an image on the retina? Or, as I envision it, would it be a focal system that produces real image pairs that are viewed with optics akin to a stereoscope?

If a fiber optics system were employed as shown in Fig. 2, does that not add pixilation to the observed scene and influence resolution?

I'm not trying to be cute or critial, just trying to understand.

Thanks,
Ed

Omid · Aug 18, 2016

elkcub said:
Omid,
I'm having difficulty understanding this. Referring to your patent, which configuration(s) apply to a riflescope vs. a binocular? Which one was incorporated into your (binocular) video demonstration above?

Hi Ed,

Your questions are very reasonable, some of them I have been trying to answer myself too! Regarding the configuration, something equivalent to Fig. 3 will work in binoculars. You just need to replace the lens-based erector assembly with a prismatic erector (e.g. Roof prisms).

A conventional telescope is afocal (when set to infinity), and the exit pupil is located a finite distance from the eye lens (which is the eye relief). The output image is located at infinity, so the eye is necessary to focus it on the retina.

Would your binocular application also be afocal, and rely on the eye to focus an image on the retina? Or, as I envision it, would it be a focal system that produces real image pairs that are viewed with optics akin to a stereoscope?

When used in the binoculars, this system produces a virtual image similar to a conventional binoculars. I am not sure if we can technically call this an 'afocal system' but practically I would say yes.

If a fiber optics system were employed as shown in Fig. 2, does that not add pixilation to the observed scene and influence resolution?

The technology of making FOFPs is now so advanced that fiber diameters of 6 microns (or even 3 microns) are possible. With such dense and small fibers (i.e. pixels), you can't see the fibers even under a 10X magnifier (I have tested this myself). There are also other solutions to make sure that no pixelation effect becomes visible.

Regards,
-Omid

ronh · Aug 18, 2016

Omid,
Thanks for the patent link.

It appears that an erected real image is focused onto a fiber bundle, which would be similar in principle to a ground glass screen but superior in resolution and brightness. This achieves the goal of the patent, a parallax free aiming device. This could be especially cool for a combat soldier who might use the device to "shoot around a corner", keeping his (or her) head out of harm's way.

But it seems to me that without an "eyepiece" to view that real image, the eye must be placed far enough away from the fiber bundle output end to focus upon it, something like a foot away. That would make the apparent field, and effective magnification quite small, wouldn't it? So it seems very unlike the traditional binocular.

I hope my criticism seems merely dumb, not impolite or unappreciative. This is what happens when you let your idea out "on the street", ha!

Ron

elkcub · Aug 18, 2016

Omed,

I believe Ron is correct if the Fig. 3 configuration were used. Fig. 4/5 configurations, however, allow for a viewer (labeled 6 in the drawings). Unlike traditional binoculars, none of these systems would be afocal or coherently coupled with the optics of the eye because there is an intermediate screen. With an optical viewer attached I would think of such devices as "dynamic stereoscopes" rather than binoculars.

It's up to you to demonstrate that such systems would be competitive with binoculars, both from a performance and cost perspective. Sorry, but I'm somewhat skeptical.

Ed

Binastro · Aug 18, 2016

Are image intensifier multi channel plates relevant here or quite different?
The resolution of these devices is not great in 2 plus versions I have used.

Omid · Aug 18, 2016

ronh said:
Omid,
Thanks for the patent link.

It appears that an erected real image is focused onto a fiber bundle, which would be similar in principle to a ground glass screen but superior in resolution and brightness. This achieves the goal of the patent, a parallax free aiming device. This could be especially cool for a combat soldier who might use the device to "shoot around a corner", keeping his (or her) head out of harm's way.

But it seems to me that without an "eyepiece" to view that real image, the eye must be placed far enough away from the fiber bundle output end to focus upon it, something like a foot away. That would make the apparent field, and effective magnification quite small, wouldn't it? So it seems very unlike the traditional binocular.

In the first embodiment, the image is to be viewed directly from on the surface of the FOFP. This requires at least 20 CM distance between the eye and the FOFP which is OK in some applications (think, e.g. an archery sight or a battle tank sight). For a normal use in riflescope, an eyepiece has been added (as Ed noted) in the configurations shown in Figs 4 and 5.

I hope my criticism seems merely dumb, not impolite or unappreciative. This is what happens when you let your idea out "on the street", ha!
Ron

No, not at all. I am glad that you and some other forum members appreciate the novel concept we are discussing here and are taking time to review and critique it. The key advantage of my idea is relaxing the strict requirement that one has to position his eye at the exit pupil of a telescope/binocular. The drawbacks are we are going to loose some light and also we have to make sure that the image doesn't look pixelated. I believe both of these objectives can be achieved with proper R&D.

Omid · Aug 18, 2016

elkcub said:
Omed,
Unlike traditional binoculars, none of these systems would be afocal or coherently coupled with the optics of the eye because there is an intermediate screen. With a viewer attached I would think of such devices "dynamic stereoscopes" rather than binoculars.

Interesting name! yes, you are not observing the image directly but through an intermediate screen. But this is not totally unusual: Think about what you see when you look through the view finder of an SLR camera (I am talking about Single-Lens-Reflex cameras, don't confuse this with a reverse Galilean viewfinder on pocket cameras). The image is formed by the lens on a receiving side of a "focusing screen" or "ground glass" plate first. The diameter of the cone of light arriving at each image point depends on the f-number of the lens. But, the diameter of the cone of lite exiting the ground glass is virtually independent of the f-number, it depends on the properties of the ground glass. The image seen through the viewfinder is very much like the image produced by my invention: there is no eye relief! Test this yourself if you have an old SLR camera

elkcub · Aug 18, 2016

Omid said:
Interesting name! yes, you are not observing the image directly but through an intermediate screen. But this is not totally unusual: Think about what you see when you look through the view finder of an SLR camera (I am talking about Single-Lens-Reflex cameras, don't confuse this with a reverse Galilean viewfinder on pocket cameras). The image is formed by the lens on a receiving side of a "focusing screen" or "ground glass" plate first. The diameter of the cone of light arriving at each image point depends on the f-number of the lens. But, the diameter of the cone of lite exiting the ground glass is virtually independent of the f-number, it depends on the properties of the ground glass. The image seen through the viewfinder is very much like the image produced by my invention: there is no eye relief! Test this yourself if you have an old SLR camera

Omid,

I understand what you're saying, but at the end of the day the system would produce two offset projected images of the world that must be viewed binocularly through an optical system. In principle it's no different than viewing offset color slides with a stereoscope. Hence, it follows that what's known about stereoscope optical design and ergonomics should be informative about how to proceed.

In this regard, it would be well worth investing in the 2003 edition of Ferwerda's book "The World of 3-D", which can be purchased used for about $15. Chapter 5 is dedicated to the optics of stereoscopes.

Nowadays this also gets into the 'virtual reality' world, and I'm sure there are books on that subject.

Ed

Omid · Aug 18, 2016

elkcub said:
at the end of the day the system would produce two offset projected images of the world that must be viewed binocularly through an optical system.

Yes, but isn't this what all binoculars do? They form two real pictures at the focal plane of the eyepieces and we view those images binocularly through two eyepieces. What would be the problem?

A system similar to my idea have been developed by the British company Vision Engineering for microscopes. They use a diffractive surface and use it in a reflective mode (in an older model, they had a transmission mode system two). It works quite nice and is a successful product.

Thank you for the 3D book. I'll try to get a copy. I already have a couple of book on binocular vision (see image below). The four volume set on the left (Handbook of Optical Systems) are the most expensive books I have ever bought, they cost more than $500 each!

elkcub · Aug 19, 2016

Omid said:
Yes, but isn't this what all binoculars do? They form two real pictures at the focal plane of the eyepieces and we view those images binocularly through two eyepieces. What would be the problem?
...

Hi Omed,

The back focal plane of a binocular objective is made to coincide with the front focal plane of the eyepiece, but no image is projected onto a surface prior to the retina. Light rays can be traced uninterrupted through the instrument-eye system.

Please review Chapter 2 of the "Visual Instrumentation" book by Mouroulis with regard to coherent vs incoherently coupled systems. By virtue of having an internal projection screen, your system is necessarily uncoupled to the optics of the observer's eye. [Because of that, incidentally, almost nothing in the remainder of the book is applicable because it deals exclusively with coherently coupled systems and retinal image quality. You're in a different domain.]

On pg. 29, para. 3

...From the foregoing, it is hopefully clear that a visual microscope or telescope is coherently coupled to the eye, while a photographic print or slide projector is not."

Since you are interested in applying the patent to hand held viewing systems, like binoculars, I think it's important to understand the differences and their implications. As I see it, everything behind and including the fiberoptic plate (Fig. 4) can be considered a stereoscope.

Ed

PS. Does the "Handbook of Optical Systems" have a chapter or section on stereoscopes?

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