LED Measurement System

As we know, there are many light sources which can be used for lighting system. In the past, when the electricity hasn’t been used for lighting technology, candle and torch were used for it. Thomas Alfa Edison started lighting technology by his invention, incandescent lamp. Then, fluorescent lamp technology has been being used. Now, the development of LED light has begun to replace fluorescent lamp and other light source. LED is light source whose its efficiency is very high because it converts directly from electricity to light.

As a light source, LED has properties as other light source, such as: Flux Luminous, Intensity, Luminance, Radiance Flux, etc. Measuring these properties needs instrument or equipment. The development instrument technology makes the measurement of Light properties (especially LED light properties) become easier. To measure LED light properties need at least spectrometer, integrating sphere, fiber optic, and software. Several companies has developed this kind of instrument in one system.

Spectrometer

Spectrometer is equipments that analyzed the wavelength of light. Light that comes to spectrometer will be refracted by prism or grating, so light will be separated based on its wavelength. This wavelength will be analyzed by CCD to be converted into electric signal.

Fiber optic

Fiber optic is used to be path of light. Fiber optic is put in front of light source, so light can enter to the fiber optic and go to spectrometer to be analyzed

.

Integrating Sphere

Integrating sphere is a hollow sphere which is coated by white color. The function of integrating sphere is to collect 

all of light emitted by light source.

PC and software

Electric signals from spectrometer are the information of light. To know what signal said, it needs process to be understood. This process is done by computer with compatible software. Spectrometer is usually completed by its software.

Spectrometer

Light is kind of electromagnetic wave. Visible light for example, this is an electromagnetic wave which has wavelength that can be sensed by human eye. Source of light may emit light not only one wavelength. White light consist many wavelength from 380 nm – 750 nm. The proof about this is when white light (such as sun light) is refracted by prism, we can see many color (from red to violet) as a result. Color of light depends on the wavelength, so we can conclude that sunlight consist many wavelength.

Spectrometer is an instrument which can be used for measure light properties. The variable can be measured by spectrometer usually is intensity. Electronic spectrometer consists of device which can convert from light to electricity, it is called CCD.

The steps inside electronic-spectrometer are started with light enter the spectrometer, then a device (Prism or grating) refracts the light based on its wavelength. For example white light will be refracted into all of visible light wavelength. These wavelengths will be converted into electric signal by CCD. This signal will be transmitted to PC to be processed. Finally we can see the spectrum of light on the PC’s monitor. Usually electronic spectrometer is completed with its software which can be used to measure in several units, such as Watt, Lumen, Lux, etc.

Spectrometer is used for many applications, Such as solution identification and LED Junction temperature Measurement.