I have this idea for creating a large flat panel display, and wonder if it's feasible.
The basic idea is for the panel to be a thin slab chamber of water or gel. The edges are coated with a reflective mirror surface, so total light reflection keeps light inside the panel. One side is perforated with tiny holes, so the water's surface tension keeps it flat.
Three stroboscope LEDs feed red, green, and blue light in turn into the edge of the slab. These need to be able to provide extremely short duration flashes at precisely
60hz (or greater).The display is shaped using a row of ultrasonic transducers along one edge of the display. These act as a phased array, concentrating sound waves onto individual pixels. The computer electronics sum up the waveforms of every displayed pixel. As a result, when the strobe flashes, the "active" pixels are places where the sound is concentrated. In these places, water pressure causes the water surface at the perforations to be bumpy. These bumps spoil total internal reflection, and as a result light can escape at the active pixels.
Note that these sound waves only concentrate onto the desired pixels momentarily. This is why a strobe is required. The light "captures" the image at the precise point in time when the sound waves are concentrated as desired. The rest of the time, these sound waves interfere in arbitrary ways. If light were applied continuously, imaging may still be vaguely possible but it will be extremely blurry--each active pixel would have an hourglass shaped halo around it.
The duration of the strobe pulses need to be maybe one microsecond or less, but the brightness needs to be able to illumate the entire panel, if necessary (for a pure white image). Is that feasible? Would multiple LEDs be necessary or better?
I'm not sure what requirements are for the linear transducer array. Assuming a pixel size of around 1mm, the transducers need to operate at at most a 1mm wavelength and need to be at most 1mm wide.
I think this concept could be suitable for inexpensive flat panel displays. Most of the display is simply a water chamber surrounded by bulk glass or plastic. One edge has the ultrasonic transducer array, which I imagine would be the most expensive component. Is there a way to make this component less expensive?
The display itself is naturally transparent. For use as a TV or computer display, you'd want it to be backed by a black coating, of course. For an artistic display, the transparency may be considered a feature rather than a flaw. This panel may be cut to any convex shape (as long as the transducer array has an unobstructed view to all pixels in the active display area).
Ideas? Criticisms?
Isaac Kuo