Holographic Keypads Float Into View

prostoalex writes "The New York Times tells the story of a Connecticut-based company called HoloTouch that is developing input devices that literally "float in the air". The technology will be licensed for information kiosks in New York city. Some other sample applications are available from the company's Web site. HoloTouch already managed to secure the patent on its technology."

Comments

Re:look before leap

[Elwood P Dowd]

Uh... people with only one eye can't see the 3D aspect of a hologram. They can see a 2D picture just fine.

If they move their head, then they can see the 3d aspect as well.

One eyed folks will do just fine here.

Re:real, or just killing real invention?

[frovingslosh]

Huh? Their patent appears to explain exactly how to do this (hint: see the "DETAILED DESCRIPTION" section).

Been there, read that. OK, maybe I just don't get it, but you tell me how The holographic image generator 200 actually manages to display a real time changing holographic image and then I'll accept that they have something. I just don't see anything in the patent or on their website that says they can really do this.

Comments about device

[merlin_jim]

Unfortunately they didn't do their homework :(

From the website:

HoloTouch, images of keypads can be any size, entirely independent of the size of the hardware.

(emphasis my own)

From the patent:

When a hologram is illuminated by a reconstruction beam, it produces a real image (which appears to be between the plane of the hologram and the viewer) and a virtual image (which appears to be behind the plane of the hologram). [snip] Thus, it is preferred that the holographic image 207 be a real image.

Quick review of holography: an extremely high resolution film takes pictures of the interference pattern generated when a coherent light beam strikes an object.

When coherent light of a similar wavelength later shines through this film, the interference patterns cause it to be shined through in exactly the same manner as the original coherent light, up to about half the resolution of the film. Most holographic film is 3000 lines per inch, so the hologram has a "resolution" of about 1500 lines per inch.

You see an image because the light reaching your eyes through the film is exactly as it would be had the object been in front of your eyes and illuminated by the original beam.

The light reaching your eyes is coming through the film and then traveling in a straight line from the film to your eyes. You can only see such light if the holograph is directly behind it, because the path of the photons cannot change after it passes through the hologram (disregarding minor lensing effects due to the atmosphere, that is)

What does this mean? Well if the hologram appears to be one half meter in front of you and the holographic film is one meter in front of you, and the holographic image appears to be 10 cm x 10 cm, then the minimum possible size for the holographic film is 20 cm x 20 cm.

I don't call that entirely independent; as a matter of fact, it's a pretty simple relationship governed by a version of the inverse square law.

Oh, an interesting fact about it is if you take a holographic film and cut it in half, because all the information about the image is stored throughout the film, you don't have half a hologram; you have a hologram of the entire object that is half the size of the original. Pretty cool stuff actually.