Polarizing organic photovoltaics (ZOPV) is a concept for harvesting energy from Liquid crystal display screens, [1] developed by engineers from UCLA. This concept enables devices to use external light and the LCD screen's backlight using photovoltaic polarizers. Photovoltaic polarizers convert this light into electricity which can be used to power the device. [2] This concept also provides multifunctional capability to devices with LCD screens as they act as photovoltaic devices and also as polarisers. [2] [3]
A liquid crystal display (LCD) is a flat panel display, electronic visual display, video display that uses the light modulating properties of liquid crystals (LCs). LCs do not emit light directly. They are used in a wide range of applications, including computer monitors, television, instrument panels, laptops tablet computers etc. [4] They are common in consumer devices such as video players, gaming devices, clocks, watches, calculators, and telephones.
Up to three-fourths of the light energy wasted from LCD backlight illumination can be retrieved and used using polarizing organic photovoltaics. They can use external light energy also apart from backlight illumination using photovoltaic polarizers, which are present within the structure of the LCD screen. [5] [6]
80% to 90% of the total energy used by any device with an LCD screen is used up by the backlight illumination. [4] As polarizing organic photovoltaics can recycle up to 75% of wasted light energy, the efficiency of the device is increased. [2] [7]
This simply incorporates additional conversion efficiency losses. These devices harvest their own light. The article cited above, "Photovoltaics Could Charge A Phone Using Its Own Backlight" is bogus and makes claims that would violate the 1st and 2nd laws of thermodynamics if true. Such a device thus could not be patented and commercialized. See also: Perpetual Motion Machine
A liquid-crystal display (LCD) is a flat-panel display or other electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers. Liquid crystals do not emit light directly but instead use a backlight or reflector to produce images in color or monochrome. LCDs are available to display arbitrary images or fixed images with low information content, which can be displayed or hidden. For instance: preset words, digits, and seven-segment displays, as in a digital clock, are all good examples of devices with these displays. They use the same basic technology, except that arbitrary images are made from a matrix of small pixels, while other displays have larger elements. LCDs can either be normally on (positive) or off (negative), depending on the polarizer arrangement. For example, a character positive LCD with a backlight will have black lettering on a background that is the color of the backlight, and a character negative LCD will have a black background with the letters being of the same color as the backlight. Optical filters are added to white on blue LCDs to give them their characteristic appearance.
Electroluminescence (EL) is an optical and electrical phenomenon, in which a material emits light in response to the passage of an electric current or to a strong electric field. This is distinct from black body light emission resulting from heat (incandescence), a chemical reaction (chemiluminescence), sound (sonoluminescence), or other mechanical action (mechanoluminescence).
A plasma display panel (PDP) is a type of flat panel display that uses small cells containing plasma: ionized gas that responds to electric fields. Plasma televisions were the first large flat panel displays to be released to the public.
An active-matrix liquid-crystal display (AMLCD) is a type of flat-panel display, the only viable technology for high-resolution TVs, computer monitors, notebook computers, tablet computers and smartphones with an LCD screen, due to low weight, very good image quality, wide color gamut and response time.
An organic light-emitting diode, also known as organic electroluminescentdiode, is a light-emitting diode (LED) in which the emissive electroluminescent layer is a film of organic compound that emits light in response to an electric current. This organic layer is situated between two electrodes; typically, at least one of these electrodes is transparent. OLEDs are used to create digital displays in devices such as television screens, computer monitors, and portable systems such as smartphones and handheld game consoles. A major area of research is the development of white OLED devices for use in solid-state lighting applications.
A flat-panel display (FPD) is an electronic display used to display visual content such as text or images. It is present in consumer, medical, transportation, and industrial equipment.
A backlight is a form of illumination used in liquid crystal displays (LCDs). As LCDs do not produce light by themselves—unlike, for example, cathode ray tube (CRT), plasma (PDP) or OLED displays—they need illumination to produce a visible image. Backlights illuminate the LCD from the side or back of the display panel, unlike frontlights, which are placed in front of the LCD. Backlights are used in small displays to increase readability in low light conditions such as in wristwatches, and are used in smart phones, computer displays and LCD televisions to produce light in a manner similar to a CRT display. A review of some early backlighting schemes for LCDs is given in a report Engineering and Technology History by Peter J. Wild.
A solar cell, or photovoltaic cell, is an electronic device that converts the energy of light directly into electricity by the photovoltaic effect, which is a physical and chemical phenomenon. It is a form of photoelectric cell, defined as a device whose electrical characteristics, such as current, voltage, or resistance, vary when exposed to light. Individual solar cell devices are often the electrical building blocks of photovoltaic modules, known colloquially as solar panels. The common single junction silicon solar cell can produce a maximum open-circuit voltage of approximately 0.5 volts to 0.6volts.
A transflective liquid-crystal display is a liquid-crystal display (LCD) with an optical layer that reflects and transmits light. Under bright illumination the display acts mainly as a reflective display with the contrast being constant with illuminance. However, under dim and dark ambient situations the light from a backlight is transmitted through the transflective layer to provide light for the display. The transflective layer is called a transflector. It is typically made from a sheet polymer. It is similar to a one-way mirror but is not specular.
Large-screen television technology developed rapidly in the late 1990s and 2000s. Prior to the development of thin-screen technologies, rear-projection television was standard for larger displays, and jumbotron, a non-projection video display technology, was used at stadiums and concerts. Various thin-screen technologies are being developed, but only liquid crystal display (LCD), plasma display (PDP) and Digital Light Processing (DLP) have been publicly released. Recent technologies like organic light-emitting diode (OLED) as well as not-yet-released technologies like surface-conduction electron-emitter display (SED) or field emission display (FED) are in development to replace earlier flat-screen technologies in picture quality.
An organic solar cell (OSC) or plastic solar cell is a type of photovoltaic that uses organic electronics, a branch of electronics that deals with conductive organic polymers or small organic molecules, for light absorption and charge transport to produce electricity from sunlight by the photovoltaic effect. Most organic photovoltaic cells are polymer solar cells.
Digital newspaper technology is the technology used to create or distribute a digital newspaper.
An LED-backlit LCD is a liquid-crystal display that uses LEDs for backlighting instead of traditional cold cathode fluorescent (CCFL) backlighting. LED-backlit displays use the same TFT LCD technologies as CCFL-backlit LCDs, but offer a variety of advantages over them.
Discotic liquid crystals are mesophases formed from disc-shaped molecules known as "discotic mesogens". These phases are often also referred to as columnar phases. Discotic mesogens are typically composed of an aromatic core surrounded by flexible alkyl chains. The aromatic cores allow charge transfer in the stacking direction through the π conjugate systems. The charge transfer allows the discotic liquid crystals to be electrically semiconductive along the stacking direction. Applications have been focusing on using these systems in photovoltaic devices, organic light emitting diodes (OLED), and molecular wires. Discotics have also been suggested for use in compensation films, for LCD displays.
A quantum dot display is a display device that uses quantum dots (QD), semiconductor nanocrystals which can produce pure monochromatic red, green, and blue light.
A text display is an electronic alphanumeric display device that is mainly or only capable of showing text, or extremely limited graphic characters. This includes electromechanical split-flap displays, vane displays, and flip-disc displays; all-electronic liquid-crystal displays, incandescent eggcrate displays, LED displays, and vacuum fluorescent displays; and even electric nixie tubes.
IPS is a screen technology for liquid-crystal displays (LCDs). In IPS, a layer of liquid crystals is sandwiched between two glass surfaces. The liquid crystal molecules are aligned parallel to those surfaces in predetermined directions (in-plane). The molecules are reoriented by an applied electric field, whilst remaining essentially parallel to the surfaces to produce an image. It was designed to solve the strong viewing angle dependence and low-quality color reproduction of the twisted nematic field effect (TN) matrix LCDs prevalent in the late 1980s.
Sun-free photovoltaics is a photovoltaics technology which does not require sunlight to produce electricity. This technique was developed by research team at Massachusetts Institute of Technology. Photovoltaic cells convert light to electricity most efficiently at specific wavelengths. The surface features of Sun-free photovoltaics is engineered such that it converts heat energy into the specific wavelengths. This increases the efficiency of existing thermophotovoltaic (TPV) systems.
A see-through display or transparent display is an electronic display that allows the user to see what is shown on the screen while still being able to see through it. The main applications of this type of display are in head-up displays, augmented reality systems, digital signage, and general large-scale spatial light modulation. They should be distinguished from image-combination systems which achieve visually similar effects by optically combining multiple images in the field of view. Transparent displays embed the active matrix of the display in the field of view, which generally allows them to be more compact than combination-based systems.
Amorphous silicon (a-Si) is the non-crystalline form of silicon used for solar cells and thin-film transistors in LCDs.
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