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Screens for TV and computer displays can be made thinner using LEDs for backlighting. [96] LEDs are small, durable and need little power, so they are used in handheld devices such as flashlights. LED strobe lights or camera flashes operate at a safe, low voltage, instead of the 250+ volts commonly found in xenon flashlamp-based
LED development began with infrared and red devices made with gallium arsenide. Advances in materials science have enabled making devices with ever-shorter wavelengths, emitting light in a variety of colors. LEDs are usually built on an n-type substrate, with an electrode attached to the p-type layer deposited on its surface.
LED lamps are often made with arrays of surface mount LED modules. A significant difference from other light sources is that the light is more directional. An LED is a "Lambertian" emitter, producing a cone of light with half-power points about 60° from the axis. A laser diode is another form of LED emitter, but produces light by a different ...
A single LED can have several phosphors at the same time. [89] [99] Some LEDs use phosphors made of glass-ceramic or composite phosphor/glass materials. [100] [101] Alternatively, the LED chips themselves can be coated with a thin coating of phosphor-containing material, called a conformal coating. [102] [103]
The first LEDs were red and yellow, and higher-frequency diodes have been developed over time. All LEDs produce incoherent, narrow-spectrum light; "white" LEDs are actually a blue LED with a yellow scintillator coating, or combinations of three LEDs of a different color. LEDs can also be used as low-efficiency photodiodes in signal applications.
About 25 years after a pregnant woman was found strangled to death in a Toronto parking lot, authorities have arrested and charged a suspect. In a Feb. 7 press release announcing the arrest of 50 ...
Prototypes have been made of flexible and rollable displays which use OLEDs' unique characteristics. Applications in flexible signs and lighting are also being developed. [168] OLED lighting offers several advantages over LED lighting, such as higher quality illumination, more diffuse light source, and panel shapes. [167]
Mayan Lopez is sharing how symptoms of her then-undiagnosed PCOS — like facial hair and weight gain — led to "self-hate" The Lopez vs. Lopez star told hosts Dr. Thaïs “Dr.A” Aliabadi and ...