Posts Tagged ‘lenses’
Single Stationary Microscope Lens Can Capture 3D Images
Postdoctoral researcher Lei Li wrote a computer program to create the lens; then he and Ohio State associate professor Allen Yi cut the lens from acrylic glass, a type of transparent plastic, with a diamond blade. The finished product is shaped like a rhinestone, with a flat top and eight surrounding facets. Unlike a gem cut for jewelry, though, these facets are not symmetrical. Each one captures images from a different angle. The images from each facet are then combined on a computer to form the 3-D image.
The engineers have successfully used the lens to create 3-D images of a ballpoint pen tip, measuring about one millimeter across, and a tiny drill bit that has a diameter of 0.2 millimeters. The technology is intended to help simplify the currently complex machinery manufacturers use to produce tiny components. While the prototype lens was created with a precision cutting machine, the researchers say it could be produced less expensively with more traditional molding.
Video: New Liquid Pistons Made of Magnetic Droplets Could Power Self-Focusing Lenses
Researchers at Rensselaer Polytechnic Institute embedded drops of ferrofluid, a liquid infused with magnetic nanoparticles, into a thin substrate that was submerged in water. Then they exposed the device to a magnetic field to make one of the droplets vibrate back and forth (up or down in the image above), which caused its partner to oscillate in a mirror pattern. This ballet displaces teeny amounts of liquid, moving it from one chamber to another, according to Amir H. Hirsa, a mechanical engineering professor at Rensselaer. The piston is superfast, allowing micro-scale devices with cycling speeds in the kilohertz range.
The liquid piston has no moving mechanical pieces, so it never suffers wear and tear, according to a Rensselaer news release. The droplet duo could be used in a wide array of devices that require reliable resonator action, like an implantable chip that slowly pumps drugs from one chamber to another, Hirsa said.
What’s more, the droplets’ shape constantly changes as they vibrate, so if you pass light through them, they function as a lens that automatically changes its focal length. Hirsa and colleagues took some video from these liquid lenses and they say its quality is comparable to a typical computer web cam. You would need special software to filter out the blurry frames, but Hirsa says it could work for handheld electronic devices as well as potential replacement eye lenses. So instead of a cool pair of frames, you could wear magnets on your head to fine-tune your vision.
Other involve trapping light at different wavelengths to produce a high-definition display. This device would instead focus light to obtain a sharp picture.
The droplets’ speed and vibration strength can be controlled by changing the strength of the magnetic field, according to Rensselaer.
The liquid piston is described in the journal .
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Microsoft’s New Lens Promises 3-D TVs Sans Glasses
The 2.5 million 3-D HDTV sets that are expected to land in homes this year might seem like a lot, but it's really only a drop in the TV bucket. Early adopters will always exist, but this current wave of next-gen home-theater gear has more standing in its way than price. Who wants to wear those glasses? (Especially when most 3-D TV packages only come with two pairs, with extras running at least $50 a pop.) Doesn't exactly make for the best 3-D World Cup viewing party, now does it?
We've seen small-scale glasses-free 3-D displays before, like the LCD screen on that use light directed at each eye individually to deliver a stereoscopic image. Microsoft's display does a similar trick, but on a much larger scale. Their lens has a series of LEDs along the bottom edge of the screen that switch off and on rapidly and at varying angles to control where the light goes.
The screen can deliver a 3-D image to two different viewers' eyes at once. In order to do so, its onboard computer has to track their eyes to target the light to each individual. In the past, such systems have been very bulky to account for air space needed between the lens and projector; Microsoft's design, though, uses a lens that tapers from 11 millimeters thick at the top to six millimeters at the bottom. This taper means that the light can travel through the lens instead of thin air, Applied Sciences Group Director Steven Bathiche told Technology Review, meaning the entire setup can substantially shrink in size.
Light from the diodes enters the lens along the bottom and bounces through the lens until it reaches the proper viewing angle, at which point it escapes.
Though the setup currently only has a viewing angle of about 20 to 40 degrees, it's still early in the development stages. One day the lens could oust the now-conventional backlight in LCD HDTVs to bring home a glasses-less screen.
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