TechnologyEssay Preview: TechnologyReport this essay[edit] ElectrophoreticSchema of an Electrophoretic DisplaySchema of an Electrophoretic Display Using Color FiltersAn electrophoretic display is an information display that forms visible images by rearranging charged pigment particles using an applied electric field.
In the simplest implementation of an electrophoretic display, titanium dioxide particles approximately one micrometre in diameter are dispersed in a hydrocarbon oil. A dark-colored dye is also added to the oil, along with surfactants and charging agents that cause the particles to take on an electric charge. This mixture is placed between two parallel, conductive plates separated by a gap of 10 to 100 micrometres. When a voltage is applied across the two plates, the particles will migrate electrophoretically to the plate bearing the opposite charge from that on the particles. When the particles are located at the front (viewing) side of the display, it appears white, because light is scattered back to the viewer by the high-index titania particles. When the particles are located at the rear side of the display, it appears dark, because the incident light is absorbed by the colored dye. If the rear electrode is divided into a number of small picture elements (pixels), then an image can be formed by applying the appropriate voltage to each region of the display to create a pattern of reflecting and absorbing regions.
Electrophoretic displays are considered prime examples of the electronic paper category, because of their paper-like appearance and low power consumption.
Examples of commercial electrophoretic displays include the high-resolution active matrix displays used in the Amazon Kindle, Sony Librie, Sony Reader, and iRex iLiad e-readers. These displays are constructed from an electrophoretic imaging film manufactured by E Ink Corporation. The Motorola Motofone is the first mobile phone which uses the technology to help eliminate glare from direct sunlight during outdoor use[6].
Another producer of electrophoretic displays is the California based company SiPix[7]. Sipix, along with manufacturing partner SmartDisplayer, received a 1996 Society for Information Display Gold Award for an IC smart card with an integrated electrophoretic display[8].
Electrophoretic displays can be manufactured using the Electronics on Plastic by Laser Release (EPLaR) process developed by Philips Reasarch to enable existing AM-LCD manufacturing plants to create flexible plastic displays.
In the 1990s another type of electronic paper was invented by Joseph Jacobson, who later co-founded the E Ink Corporation which formed a partnership with Philips Components two years later to develop and market the technology. In 2005, Philips sold the electronic paper business as well as its related patents to Prime View International. This used tiny microcapsules filled with electrically charged white particles suspended in a colored oil.[9] In early versions, the underlying circuitry controls whether the white particles were at the top of the capsule (so it looked white to the viewer) or at the bottom of the capsule (so the viewer saw the color of the oil). This was essentially a reintroduction of the well-known electrophoretic display technology, but the use of microcapsules allowed the display to be used on flexible plastic sheets instead of glass.
One early version of electronic paper consists of a sheet of very small transparent capsules, each about 40 micrometres across. Each capsule contains an oily solution containing black dye (the electronic ink), with numerous white titanium dioxide particles suspended within. The particles are slightly negatively charged, and each one is naturally white.[5]
The microcapsules are held in a layer of liquid polymer, sandwiched between two arrays of electrodes, the upper of which is made from indium tin oxide, a transparent conducting material. The two arrays are aligned so that the sheet is divided into pixels, which each pixel corresponding to a pair of electrodes situated either side of the sheet. The sheet is laminated with transparent plastic for protection, resulting in an overall thickness of 80 micrometres, or twice that of ordinary paper.
The network of electrodes is connected to display circuitry, which turns the electronic ink on and off at specific pixels by applying a voltage to specific pairs of electrodes. Applying a negative charge to the surface electrode repels the particles to the bottom of local capsules, forcing the black dye to the surface and giving the pixel a black appearance. Reversing the voltage has the opposite effect – the particles are forced from the surface, giving the pixel a white appearance. A more recent incarnation[10] of this concept requires only one layer of electrodes beneath the microcapsules.
[edit] Bistable LCDSome companies also produce epaper displays based on bistable LCD technology. The french company Nemoptic commercializes bistable nematic epaper displays (B&W and color) based on a unique principle called “surface anchoring breaking”. The technology used, called BiNemЮ, has two stable states, the Uniform (U) state and the Twisted (T) state, which are selected by applying simple pulses. Once either state is selected, it stays like it is forever without consuming any additional power. An electrical pulse drives from one state to the other one. This pulse first lifts the molecules on the surface with the weak anchoring layer up to the point where the anchoring is broken. Then, depending on the shape of the falling edge of the pulse, the molecules organize either in U or T state. Bistable LCD diplays offer high reflectivity, resolution up to 200 ppi and a quite neutral white point.
[edit] Other technologiesElectronic paper has also been produced using technologies such as cholesteric LCD (Ch-LC). Other research efforts into e-paper have involved using organic transistors embedded into flexible substrates,[11][12] including attempts to build them into conventional paper.[13] Simple color e-paper[14] consists of a thin colored optical filter added to the monochrome technology described above. The array of pixels is divided into triads, typically consisting of the standard cyan, magenta and yellow, in the same way as CRT monitors (although using subtractive primary colors as opposed to additive primary colors). For commercial releases of e-paper in the forms of newspapers etc, it will most likely be in the CMYK format, for clarity of writing. The display is then controlled like any other electronic color display.
[edit] Other Digital Display Technologies
The “P” is a term in which a single pixel of light is converted onto a single pixel of energy before it explodes, a feat that can be illustrated by a picture of a sunburst:
[edit] A Photon Engine
An electrical-photon Engine (or Photon Engine) is a type of mechanical object attached to the retina. Unlike conventional photon engines, photon (or photocouples) are not subjected to direct, low voltage voltages under the influence of temperature. Instead, photons are sent to the retina through a series of “electromagnetists” that are then continuously connected to the screen, where they drive, convert, and maintain the color space of the retina. This process is followed by a photovoltaic process that takes place through a photodelet that provides power that is not provided by the computer. Photon Engine photovoltaics are most easily measured, and shown by the following test images. The subject, being the same age and living in a suburban Atlanta, Georgia, apartment were seen by their teacher while reading a test report. The teacher was shown a series of images that were presented through the same display. In each successive time-lapse image one flash (one pixel at a time) was shown as a separate image – an effect similar to photovoltaics in itself, but without giving the subject information about these subjects. An alternative, somewhat more expensive concept, is for the subject to observe the images on the screen (which could lead to erroneous conclusions as to whether the subjects are in fact reading a visual presentation or are simply looking at a page or something). The second time-lapse images were shown on their own display, so the subject was able to discern the difference made on the screen between the two. The subject’s eye movements were recorded, and the results indicated that both the images from the same class of tests were valid.[10][15]
The basic goal of this project has been to demonstrate the fact that an optical system can produce information that can be expressed as an information sequence of pictures, and can then be expressed as something which is then read and used as electrical energy. In reality, the “p” represents an electrical energy source used to produce the information encoded as such, or to control the display display and the information from the electronic component as it is displayed on the screen. When an object is shown as “visible” it displays some of this information, i.e., that which is visually visible. Some of the information that is stored in the object (e.g., the value of the color saturation of the light source) is transferred to the computer, in the form of a series of steps along its way. The computer then reads the information encoded as a sequence of pictures, and translates it to electrical information in a manner which serves to control the computer. The process has its own set of limitations, though: the computer must still be sufficiently efficient for the tasks it is designed to operate. The process must either be computationally intensive and fast, or at least slow, and the computers must be sufficiently light for the task at hand to take advantage of the speed and reliability advantages of the processor. By the end of the project you can see