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P-132: Holographic Pyramid

by on Feb.05, 2017, under Inventions

I have been wanting to build a holographic pyramid for a while, and I am finally ready to attempt it.

The concept behind holopyramids is very simple, and it based on “Peppers ghost”. Basically, a glass or clear plastic 4-sides pyramid is created and placed either over or under a screen.
The light from the screen will be reflected in such a way that the image on the screen will appear to hover in mid air. The effect is supposed to be quite striking when done properly.

I have learned (From HERE) that add a light to the center of the pyramid, and adding a tinted material to the pyrmaid prevents double-reflection and improves the effect.

The only thing I am not sure of is the angle that the pyramids sides should be. I have chosen 60 degrees, this means each side is an equilateral triangle. I assumed initially that 45 degrees would have been better, but I made a few paper models, and this just didn’t seem right.

Since light bounces off of an object at the same angle that it strikes it at, this means that the light from the screen will be reflecting off of the pyramid at 60 degrees. This probably means that I will need to mount the monitor on the bottom, and place the pyramid on top, and then view it from above. This will also mean that I won’t need to build a stand for the monitor, which I would have had to do if I wanted to mount the monitor on top and put the pyramid on the bottom.

The only disadvantage with this approach is that the screen of the monitor will be visible, in addition to the reflection, which might spoil the illusion. However, if I mount the monitor on top, I would need to mount the entire assembly high off of the ground in order for the user to be able to see the reflection properly, without it being blocked by the rear of the monitor, so a bottom mounted monitor is probably going to work out easier.

The next goal is to buy the perspex glue and the tint material. Perspex glue has the same refractive index as perspex itself, so it shouldn’t show a visible seam when it hardens.


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