In theaters, 3-D movies are everywhere. But how about a 3-D holographic movie on your mobile phone?
At Hewlett Packard Laboratories, a team led by physicist David Fattal has found a way to make 3-D, hologram-like displays for tiny screens -- no glasses required. And they've done it using inexpensive, readily available parts.
The still images and video created are visible from wide angles, unlike other 3-D imaging technologies, which tend to limit how far to one side the viewer can be from the hologram. The research appears today in the journal Nature.
"For a mobile device, it needs a wider angle [than a television] because you are more likely to tilt your hand, and we want the feeling of a virtual object in the screen in front of you," Fattal said at a press briefing.
The HP team built the display using a thin piece of glass, a liquid-crystal display and light-emitting diodes (LEDs). First, the researchers etched 500,000 circles – essentially pixels -- into the surface of the glass, each one comprised of a striped grating pattern made from sub-micrometer-sized grooves.
Next, they put a layer of liquid crystal display on top of the glass. Then the scientists surrounded the glass with the LEDs. Light from the LEDs was directed into the glass from the side. Once inside, the light bounced around the thin layer of glass and then escaped out the top through the 500,000 etched pixels.
When the light escaped, it came into contact with the grating patterns, which altered the light's direction. The LCD layer was used to control each pixel's brightness.
Different groups of pixels shining in different directions made one part of a 3-D image. In fact, 14 different images are combined to make a three-dimensional picture of say, a turtle.