There are currently two ways to make white light with LEDs. One method mixes multiple wavelengths of different LEDs to make white light (i.e. RGB); allowing the lighting designer to tune the white light to a specific color temperature.
The second method uses a blue Indium-Gallium-Nitride (InGaN) LED with a phosphor coating to create white light. This is the method that results in the more commonly seen “white LED”.
A lighting-emitting diode (LED) is a semiconductor device that emits incoherent narrow-spectrum light when electrically biased in the forward direction of p-n junction. The color of the emitted light depends on the composition and condition of the semiconducting material used, and can be infrared, visible, or near-ultraviolet.
Lumens in an international unit that refers to the amount of light that a light source produces. For example, a 60 Watt incandescent lamp provides about 800 lumens. A 1 Watt LED provides 85 lumens and up.
Phosphor is an inorganic chemical compound processed into a powder and deposited inside the dome of an LED packaging. Phosphors are designed to convert the wavelength of light. Foryard Optoelectronics LEDs use proprietary phosphors from the global leading company.
A p-n junction is formed by combing N-type and P-type semiconductors together in a very close contact. The term junction refers to the region where the two types of semiconductor meet. The junction temperature refers to the temperature measured at p-n junction, which is also the core of an LED.
The emission angle refers to as the 2θ½ indicates how focused the light is when emitted from the LED. This angle is determined by measuring the angle from direct on-axis to the angle where light intensity falls to half of the on-axis 9 intensity, and multiplying this difference by 2. The choice of viewing angle also affects the LED output intensity. Foryard Optoelectronics LEDs are available in various emission angles.
Correlated Color Temperature (CCT) is a characteristic of visible light that has important applications in lighting. The color temperature of a light source is determined by comparing its hue with a theoretical, heated black-body radiator. The Kelvin temperature at which the heated black-body radiator matches the hue of the light source is that source’s color temperature.
Color Rendering Index (CRI) is a measure of the ability of a light source to reproduce the colors of various objects being lit by the source. It is a mathematical formula describing how well a light source’s illumination compares to the illumination provided by a reference source. The index provides a number up to 100 for ideal light.
Light could be split into many colors. The colors produced by light are arranged in a precise array or spectrum. The order of color is constant, and each color has a unique signature identifying its location in the spectrum. The signature of color is the wavelength of light.
Solid State Lighting (SSL) refers to a type of lighting that utilizes LEDs as sources of illumination rather than electrical filaments or gas. The term “solid state” refers to the fact that light in an LED is emitted from a solid object – a block of semiconductor – rather than from a vacuum or gas tube, as is the case in traditional light sources.