Character LCD Modules performance of the main parameters of evaluation

Typically, OLED light-emitting materials and device performance from the luminescent properties and electrical properties of two aspects to evaluate. Luminescent properties include the emission spectra, emission luminance, luminous efficiency, light color, and life; the electrical properties include the relationship between current and voltage, the relationship between luminance and voltage, these are the OLED materials and devices to measure performance of the main parameters .
1, the emission spectrum

Refers to the emission spectrum of the fluorescence emitted by the various wavelength components of the relative intensity, also called the relative fluorescence intensity versus wavelength distribution. Emission spectra of various types generally used to measure the fluorescence measuring instrument, the measurement method is: fluorescence irradiated by monochromatic emitter detector, scanning monochromator emitter and detection of various wavelengths corresponding to the fluorescence intensity, and then recorder records the emission wavelength of the fluorescence intensity of the curve, the emission spectrum is obtained.

There are two types of OLED emission spectrum, i.e. the photoluminescence (PL) spectra and electroluminescent (EL) spectra. PL spectrum of the excitation light required, and to the wavelength and intensity of excitation light remains unchanged; EL spectrum of the excitation energy is needed, can be measured at different voltage or current density the EL spectra. The EL spectrum of the device by comparing with a different carrier transport material and a luminescent material PL spectra The location of the composite can be drawn and the actual light-emitting substance useful information.
2 and luminance

Brightness is measured in cd / m, which means that the luminous intensity per square meter, brightness is generally used to measure the luminance meter. The first production of the brightness of the OLED device has exceeded the 1000cd / ㎡, and now the brightest OLED brightness can exceed 140000cd / m. Serial Lcd Display Module

3, the luminous efficiency

OLED luminous efficiency can be used quantum efficiency, power efficiency and luminous efficiency to represent.
Ηq quantum efficiency means the output photon number Nf and the injected electron-hole pairs in the ratio of the number Nx. Quantum efficiency is further divided into internal quantum efficiency ηqi and external quantum efficiency ηqe. Ηqi internal quantum efficiency of the device is generated internally by the complex number of photons of radiation into electron-hole pairs and the ratio of the number; fact, the luminous efficiency of the device by the external quantum efficiency ηqe to reflect, expressed by the following formula.

External quantum efficiency can be measured using an integrating sphere photometer unit time total flux emitting device, obtained by calculation of the external quantum efficiency of the device.

Excitation photon energy is always greater than the energy of the photons emitted light when the excitation wavelength than the length of a lot of light emission, this energy loss is very big, and the quantum efficiency does not reflect this energy loss, power efficiency needed to reflect . Power efficiency ηp, also known as energy efficiency means the output optical power Pf and electric power input ratio Px. Measure of a light emitting device function, multi-lumen efficiency of this parameter. Luminous efficiency ηl, also called photometric efficiency, luminous flux emitted L (in lumens) and the input of the ratio of the electric power Px. OLEDs

Where, S is emitting area (square meters), B for the luminance (cd / ㎡), I and V were applied when measuring the brightness of the bias current and voltage, J is the corresponding current density (A / m), Lumen efficiency of the unit is lm / W.