Sent from my iPad
Sunday, January 31, 2016
Posted by John Sokol at Sunday, January 31, 2016
Wednesday, January 27, 2016
"No Cost" License Plate Readers Are Turning Texas Police into Mobile Debt Collectors and Data Miners | Electronic Frontier Foundation
Posted by John Sokol at Wednesday, January 27, 2016
Saturday, January 09, 2016
This is the Darkest Material Known to Man
Vantablack is a material that is so dark, our eyes can’t see any of its contours.
Thursday, January 07, 2016
Optotune’s focus tunable lenses are shape-changing lenses based on a combination of optical fluids and a polymer membrane. The core element consists of a container, which is filled with an optical liquid and sealed off with a thin, elastic polymer membrane. A circular ring that pushes onto the center of the membrane shapes the tunable lens. The deflection of the membrane and with that the radius of the lens can be changed by pushing the ring towards the membrane or by exerting a pressure to the outer part of the membrane or by pumping liquid into or out of the container.
Optotune uses electroactive polymers (EAPs) as an electrostatic actuator for its series of laser speckle reducers. These so-called "artificial muscles" can undergo a large amount of deformation while sustaining large forces. While today's piezoelectric actuators only deform by a fraction of a percent, EAPs can exhibit a strain of up to 380%. There are different types of EAPs. Optotune has specialized in dielectric electroactive polymers (DEAPs) as described below. A detailed discussion on all types of EAPs can be found here.
Monday, December 21, 2015
Sunday, December 20, 2015
Electrowetting displays are just as capable as the liquid crystal displays in tablets and notebooks, but they are three times more efficient. Johan Feenstra, who heads Samsung's electronic display research center in the Netherlands, explains how they work.
This e-paper is currently under development by Ricoh.
It has a unique structure, with layers of a new electrochromic material that turn magenta, yellow, and cyan from their transparent state. In this way, Ricoh's e-paper enables a bright, full-color display, like ordinary paper, which hasn't been possible with e-paper until now.
This prototype is a 3.5-inch, QVGA display, with a pixel density of 113.6 ppi. Its reflectivity is 70%. Compared with current color-filter displays, this e-paper is 2.5 times brighter. It has a color reproduction range of 35%, higher than that of a newspaper, which is 31% in Japan.
"To produce colors, CMY subtractive mixing is ideal, and that's the model used in printing. We've implemented this by coating the panel with layers of yellow, magenta, and cyan. Ordinarily, if you try to use layers like this, you need an electrode driver for each layer. But in this display we're developing, the electrodes are active TFTs. So, we can achieve all colors with a single TFT, by switching the electrodes on the display side."
The material used for the chromic layers is transparent in its oxidized state, but becomes colored when it's reduced. To achieve a color display, rewriting is done three times in the order magenta, yellow, cyan. As the spaces between the electrochromic layers are narrow, at about 2 microns, the result is an ideal color-mixing display.
"The stage we're at right now is, we're checking that this model works with an actual active panel. Regarding the color drive, we haven't refined this yet, so switching takes over a second for each color. But the reaction speed of the chromic material is, ideally, about 100 ms."
"From now on, we'd like to increase the size to 6 inches, then 10 inches. We also want to work on achieving stable driving and faster response."
Saturday, November 14, 2015
Posted by John Sokol at Saturday, November 14, 2015