Polarizing organic photovoltaics (ZOPV) is a concept for harvesting energy from Liquid crystal display screens, developed by engineers from

UCLA The University of California, Los Angeles (UCLA) is a public land-grant research university in Los Angeles, California. UCLA's academic roots were established in 1881 as a teachers college then known as the southern branch of the California ...

. 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. This concept also provides multifunctional capability to devices with LCD screens as they act as photovoltaic devices and as polarisers.

Background

A liquid crystal display (LCD) is a

flat panel display 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. Flat-panel displays are thin, lightweight, provide better l ...

electronic visual display An electronic visual display, informally a screen, is a display device for presentation of images, text, or video transmitted electronically, without producing a permanent record. Electronic visual displays include television sets, computer monito ...

video display A display device is an output device for presentation of information in visual or tactile form (the latter used for example in tactile electronic displays for blind people). When the input information that is supplied has an electrical signal the ...

that uses the light modulating properties of

liquid crystals Liquid crystal (LC) is a state of matter whose properties are between those of conventional liquids and those of solid crystals. For example, a liquid crystal may flow like a liquid, but its molecules may be oriented in a crystal-like way. The ...

(LCs). LCs do not emit light directly. They are used in a wide range of applications, including computer monitors,

television Television, sometimes shortened to TV, is a telecommunication medium for transmitting moving images and sound. The term can refer to a television set, or the medium of television transmission. Television is a mass medium for advertisin ...

, instrument panels, laptops

tablet computer A tablet computer, commonly shortened to tablet, is a mobile device, typically with a mobile operating system and touchscreen display processing circuitry, and a rechargeable battery in a single, thin and flat package. Tablets, being com ...

s etc. They are common in consumer devices such as video players, gaming devices,

clock A clock or a timepiece is a device used to measure and indicate time. The clock is one of the oldest human inventions, meeting the need to measure intervals of time shorter than the natural units such as the day, the lunar month and t ...

s, watches, calculators, and

telephone A telephone is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most efficiently the human voice, into e ...

Operation

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.

Advantages

80% to 90% of the total energy used by any device with an LCD screen is used up by the backlight illumination. As polarizing organic photovoltaics can recycle up to 75% of wasted light energy, the efficiency of the device is increased.

Disadvantages

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 Perpetual motion is the motion of bodies that continues forever in an unperturbed system. A perpetual motion machine is a hypothetical machine that can do work infinitely without an external energy source. This kind of machine is impossible, a ...

References

External links

* Polarizing Organic Photovoltaics
Supporting Information
{{Photovoltaics Photovoltaics Solar cells