To the human eye there appears to be a glowing three-dimensional butterfly
moving around inside this black box. In fact all it is, is a tiny polystyrene bead.
Wow, that's really small.
Yes, it's like a one millimeter, two millimeter bead.
It's suspended and we can move it so fast to create a 3D shape.
This is a volumetric display. It's an image that exists in real 3D space and this latest
development in the field is unique in that it uses sound waves not only to
create the image but also to add audio and tactile sensations.
Oh yep you can feel, it's like a really, oh like a kind of gentle buzz or breeze.
My name's Lizzie Gibney and I've come to the University of Sussex in the UK to see that display
for myself. The most surprising thing about it is that it doesn't look like a
flat projection. You can see that it's really floating there in three
dimensions and in person the image doesn't flicker like it does on camera.
People don't believe it and then there's this magical moment where they go
like "wow that's real"
The display works by a process called acoustic levitation.
In the walls of this box are arrays of speakers producing sound waves.
So by using the ultrasound, creating a standing wave and this small tiny small bead.
The speaker's create areas of high pressure
that can trap a polystyrene bead and suspend it in midair. Moving the
bead around and shining a light on it creates a glowing moving dot. Move that
dot around fast enough, and you can create shapes in the air.
What we've created is an acoustophoretic volumetric display. So we basically use
sound to trap a lightweight object in free space and
we can update its position at very high update rates. So fast that persistence of
vision happens and you think it's a full object
The team was inspired by research
published last year from Brigham Young University the American group had
successfully created a volumetric display by steering tiny particles of
cellulose using laser light.
They were trapping a particle with lasers and
doing something very similar and for us, to be honest, we were not even thinking
that that could be a possibility you know, but we looked at each other and said like
"You think we can do that?" or like "I don't know let's try"
The team at the University of Sussex has
been working on using sound waves to move small objects or create sensations
for a few years. But the big challenge in creating a volumetric display was to get
the beads moving fast enough that it appears as a single non moving image.
To see as a image for human eyes the whole path for example if you want
to create a circle, this circle should be scanned in 100 milliseconds, something like that.
So the beads should be moved so fast to create this path in 100 milliseconds.
But actually that's not the end of it right, so because we are
updating at that speed we can also create audio and tactile feedback so the
object is singing as it's moving and at the same time if you bring your
hand close to it you will get a sensation of touch.
The researchers can use the same waves of pressure that control the bead to create ripples in
the air. Fluttering on a finger to give a tactile experience that's something that
no other kind of volumetric display can do.
We create that focusing point to
another place for tactile feedback so it's like a levitation, tactile,
levitation, tactile, so we can switch so quickly.
But it's so fast, we, you don't
see it when you're watching. You don't hear it.
It does make you feel like you're getting closer to something. Something
real, like batting wings or something.
And by using the interactions between
ultrasound waves the display can even produce audible sound.
"Five"
"Four"
"Three"
"Two"
"One"
"Zero"
At the moment the display can only create small, simple shapes. But if the team can get their
beads moving even faster, or can manipulate multiple beads they could
create bigger and more complex images. And the team hopes that this could be
the start of 3D displays becoming part of everyday life.
The idea of just 3D content to be something that's there. You go, you use it
whenever you need to use it. You don't need to use it, you don't, or I need to be
seeing that 3D content but also my notes or just check what time it is, you know.
Like blending that content in our real day-to-day life just in a seamless
manner it's something that's very valuable.
This is literally our first step.
We've got a long way to go but the interesting bit is that the fundamentals
that are underpinning this kind of displays they are strong, they can really
deliver all of this, and I think that's very exciting.