More about LED
... The LED has a semiconductor chip placed in its centre. The semiconductor consists of two regions namely a P region that has positive charge carriers and an N region with negative charge carriers. There are three layers in the chip. An active photon generating material is sandwiched between the P and ...
... The LED has a semiconductor chip placed in its centre. The semiconductor consists of two regions namely a P region that has positive charge carriers and an N region with negative charge carriers. There are three layers in the chip. An active photon generating material is sandwiched between the P and ...
Light and Color
... Frequencies below the visible spectrum are called infrared and those above the violet are called ultraviolet. The instrument used to measure wavelengths of light is called a spectroscope. Quantum Theory of the atom says that an electron in the electron cloud can only absorb energy if that energy is ...
... Frequencies below the visible spectrum are called infrared and those above the violet are called ultraviolet. The instrument used to measure wavelengths of light is called a spectroscope. Quantum Theory of the atom says that an electron in the electron cloud can only absorb energy if that energy is ...
Fundamentals of Linear Electronics Integrated & Discrete
... • Display devices, such as CRT or LCD computer screens. • Light sensors, including infrared security systems. • Digital data transmission over fiber-optic cables. ...
... • Display devices, such as CRT or LCD computer screens. • Light sensors, including infrared security systems. • Digital data transmission over fiber-optic cables. ...
Module 6: Field Emission Display
... optimized for high voltage and low current density (few mA/cm 2). The use of high voltage (>3KV) allows the backside aluminization of the phosphor screen. Many CRT phosphors lose 50% of their initial efficiency (200 C/cm 2) electron dose due to Coulombic aging. FEDs require higher current densities ...
... optimized for high voltage and low current density (few mA/cm 2). The use of high voltage (>3KV) allows the backside aluminization of the phosphor screen. Many CRT phosphors lose 50% of their initial efficiency (200 C/cm 2) electron dose due to Coulombic aging. FEDs require higher current densities ...
Module 5: Electroluminescent Displays
... is an insulating layer between the Al electode and phosphor layer to avoid dielectric breakdown. This insulating layer may not be necessary if ZnS grains are completely isolated from each other. To obtain EL emission, an electric field of 1 - 10 V/mm is required. Luminance increases proportionally w ...
... is an insulating layer between the Al electode and phosphor layer to avoid dielectric breakdown. This insulating layer may not be necessary if ZnS grains are completely isolated from each other. To obtain EL emission, an electric field of 1 - 10 V/mm is required. Luminance increases proportionally w ...
Facts About Ultra Violet (UV) Lights
... more than once every 8 hours will diminish the longevity of the bulb. There are factors that will influence sensitivity of bacteria to UV. High humidity and low temperature will decrease its effectiveness. Temperatures of 36 degrees will reduce the efficiency to approximately 60%. ...
... more than once every 8 hours will diminish the longevity of the bulb. There are factors that will influence sensitivity of bacteria to UV. High humidity and low temperature will decrease its effectiveness. Temperatures of 36 degrees will reduce the efficiency to approximately 60%. ...
Hands-on Activities with LEDs and Light
... We measured with the voltmeter the voltage across the leads of the LED (each of these five LEDs). So we constructed a data table (shown above). ...
... We measured with the voltmeter the voltage across the leads of the LED (each of these five LEDs). So we constructed a data table (shown above). ...
COLORIMETRY AND SPECTROPHOTOMETRY
... Colorimetry is the use of the human eye to determine the concentration of coloured solution Spectrophotometry is the use of instruments to make the same measurements. It extends the range of possible measurements beyond those that can be determined by the eye alone. ...
... Colorimetry is the use of the human eye to determine the concentration of coloured solution Spectrophotometry is the use of instruments to make the same measurements. It extends the range of possible measurements beyond those that can be determined by the eye alone. ...
Fluorescent Lamp Phosphors - The Electrochemical Society
... emitting levels are resonant with the lowest Gd3+ excited states (6PJ). Energy transfer from Ce3+ to Gd3+ energy transfer is an efficient process. Efficient green luminescence is generated when the activator (Tb3+) ions trap the excitation energy that is percolating over the Gd3+ ions. The quantum e ...
... emitting levels are resonant with the lowest Gd3+ excited states (6PJ). Energy transfer from Ce3+ to Gd3+ energy transfer is an efficient process. Efficient green luminescence is generated when the activator (Tb3+) ions trap the excitation energy that is percolating over the Gd3+ ions. The quantum e ...
HIGH EFFICIENT LIGHT EMITTING DEVICES WITH ADDITIONAL
... LED devices. LED devices with an n-UV Ga(In)N chip as well as blue GaN chip and multiexcited phosphors were developed and created. These LEDs for white light generation show better quantum yield of green and red phosphors, higher total brightness, and improved color rendering index. 1. Introduction ...
... LED devices. LED devices with an n-UV Ga(In)N chip as well as blue GaN chip and multiexcited phosphors were developed and created. These LEDs for white light generation show better quantum yield of green and red phosphors, higher total brightness, and improved color rendering index. 1. Introduction ...
Diapositive 1 - Lightolier
... Dimming Capability • In comparison to compact fluorescent products which require specific, and often expensive, dimming controls Calculite solid-state down lights can be dimmed down as low as 5%* using off-the-shelf electronic dimmers. ...
... Dimming Capability • In comparison to compact fluorescent products which require specific, and often expensive, dimming controls Calculite solid-state down lights can be dimmed down as low as 5%* using off-the-shelf electronic dimmers. ...
Fluoroscopic Unit (Bushong, chapter 21)
... falling on it. -# of electrons proportional to intensity of incident x-rays. 25,000 volts is maintained across the tube between photcathode and anode. near anode is output phosphor where the electrons interact and produce a burst of light. accurate image pattern = precise electron pattern fro ...
... falling on it. -# of electrons proportional to intensity of incident x-rays. 25,000 volts is maintained across the tube between photcathode and anode. near anode is output phosphor where the electrons interact and produce a burst of light. accurate image pattern = precise electron pattern fro ...
Book Light
... A roaming electron has more energy than an electron bound to an atom (in a hole). That energy is given off as light. ...
... A roaming electron has more energy than an electron bound to an atom (in a hole). That energy is given off as light. ...
Phosphor
A phosphor, most generally, is a substance that exhibits the phenomenon of luminescence. Somewhat confusingly, this includes both phosphorescent materials, which show a slow decay in brightness (> 1 ms), and fluorescent materials, where the emission decay takes place over tens of nanoseconds. Phosphorescent materials are known for their use in radar screens and glow-in-the-dark toys, whereas fluorescent materials are common in cathode ray tube (CRT) and plasma video display screens, sensors, and white LEDs.Phosphors are often transition metal compounds or rare earth compounds of various types. The most common uses of phosphors are in CRT displays and fluorescent lights. CRT phosphors were standardized beginning around World War II and designated by the letter ""P"" followed by a number.Phosphorus, the chemical element named for its light-emitting behavior, emits light due to chemiluminescence, not phosphorescence;