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Re: HMDs

Chris Hardaker wrote:
> 
> How about a prism based device. use 3 primary colours (no refraction). If
> you project a beam onto prism and then rotate the prism, the beam sweeps
> from one side to the other. Once you transition over the corner of the
> prism, you should jump back to one side. That only leaves the vertical axis.
> If you can change the angle of light entry into the prism, then the prism
> should exaggerate the effect. So spin the prism, and then tilt is slightly,
> spin it again.. etc.
> 
> Sounds passable in theory.
> 
> Chris Hardaker
> 
> -----Original Message-----
> From: Thor Harald Johansen [mailto:]
> Sent: Friday, August 06, 1999 12:15 PM
> To: Wearable Hardware
> Subject: HMDs
> 
> Hi!
> 
> I've been thinking about HMDs lately.
> 
> What's the cheapest possible way of making the smallest possible graphical
> display?
> 
> I've got this idea, it could be bad, but let's go:
> 
> Build some kind of a fast, tiny rotating device, allowing for rotation in
> both horizontal and vertical directions, directed by two currents (an X
> current, and a Y current). Put a very small, but focused light source on the
> front of the device (could be a led with a lens or something). Make
> electronics that controls the rotating device to steadidly increase the X
> voltage to the maximum, then increase the Y voltage one "step", and decrease
> the X voltage down to the minimum again. Repeat this until the max Y voltage
> has been reached, then reverse the process by decreasing the Y voltage
> instead of increasing it. At the same time as doing this, get the driving
> electronics to load values from a buffer, setting the focused light source
> to that value (a led has approx 2 volts max, so 0-255 will turn into 0-2
> volts). Aim this construction against a partially transparent surface (could
> be very thin white paper). Voila! You have a television screen using lights
> instead of a catode cannon, and a piece of paper instead of a phosphor
> surface. Of course, this way of doing it would cause some vibration, but it
> may be worth a try.
> 

correct me if I'm wrong, but isn't this a similar principle that is used
in the private eye ??
I know that the PE vibrates, and I thought this was due to a spinning
mirror inside ??

Scoobz

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