LED chip is the LED lamp bead of the component, is an important part of it, light is the LED chip. There are the following differences between the two: the light concentration of the two is different, the range is different: the Angle of the LED lamp bead is very small, belongs to the light is relatively concentrated, the range is very far, but the irradiation range is limited led chip ; The general Angle of the LED patch is very large, which belongs to the relatively scattered light and wide irradiation range.But the range is close.
LED chip: also known as led light chip, is the core component of led lamp, that is, refers to the P-N junction. A solid-state semiconductor device. Lamp bead: light emitting diode abbreviation for LED. Wafer: is the core part of the LED, a single grain is fixed on the plastic or ceramic chip base.
The LED chip is a solid-state semiconductor device that can directly convert electricity into light. It is the heart of the LED lamp bead. The LED lamp bead is attached to one end of the LED chip on a bracket, one end is negative, and the other end is connectedConnected to the positive electrode of the power supply, the whole wafer is encapsulated by epoxy resin and consists of a luminous body.
So tell you, the chip is the most important part of the composition of the lamp bead, of course, is also the most expensive place, the quality of the chip directly affects the quality of the lamp bead, not you say deep led chip , afraid you listen more boring, the service life of the lamp bead should not be called shelf life, that is, the ability to prevent color decay.
1, red and green lightThe materials used are: Gallium phosphide (GaP); 2, the chip area is generally 12mil^2 (0.0254mm/mil) up to 40mil^2; 3, luminous Angle: a, high pointing type (concentrating). Half-value Angle 5-- 20°, or less; With high directivity, it can be used as a local lighting source without scattering agent; b, standard type. Usually used as an indicator, half value Angle 20-- 45°.
2, the LED chip is also known as the LED light chip, is the core component of the LED lamp, that is, the P-N junction. Its main function is: putElectrical energy is converted into light energy, and the main material of the chip is monocrystalline silicon.
3, evaporation, yellow light, chemical etching, fusion, grinding; Then the LED chip is sliced, tested and sorted, and the required LED chip can be obtained. If the chip is not clean enough, the evaporation system is not normal, which will lead to the evaporation of the metal layer (refers to the electrode after etching) will fall off, the appearance of the metal layer will change color, gold bubble and other abnormalities.
Forward operating current If it means that the light-emitting diode emits light normallyIs the positive current value. In actual use, IF below 0.6·IFm should be selected according to needs. Forward operating voltage The operating voltage given in the VF parameter table is obtained at a given forward current. It is generally measured at IF=20mA. The forward working voltage VF of LED is 4 ~ 3V. When the external temperature rises led chip , VF will decrease.
led chip We have done this test using an oscilloscope to measure the LED drive current waveform of any colorTo determine the "refresh frequency", measured at 200Hz under the white field; At low gray level, such as level 3 gray level, the measured frequency is as high as ten kHz, which is measured by PR-650 spectrometer. Whether in the white field, or in the gray level of 200, 100, 50, etc., the flicker frequency of the measured light source is 200Hz.
LED chip forward operating voltage VF: The operating voltage given in the parameter table is obtained at the given forward current. It is generally measured at IF=20mA. The forward working voltage VF of LED is 4 ~ 3V. When the outside temperature rises, VF will decrease.V-I characteristics: The relationship between the voltage and current of the light-emitting diode, when the forward voltage is positive less than a certain value (called the threshold value), the current is very small and does not emit light. LED chip sorting is very difficult, the main reason is that the LED chip size is generally small, from 9mil to 14mil (0.22-0.35 microns). Such a small chip requires a microprobe to complete the test, and the sorting process requires precise mechanical and image recognition systems, which makes the cost of the equipment very high and the test speed is limited. If calculated in accordance with 25 days per month, the capacity of each sorting machineIt is 5KK per month.
The data shift clock determines the transmission speed of the display data, and plays a crucial role in the update rate of the LED display data. As a large-size display device, the display refresh rate should be above 85Hz to ensure a stable picture (no scanning flicker). The high data shift clock is the basis for the LED display to obtain a high refresh rate picture, and the current mainstream constant current source chip shift clock frequency is generally above 15MHz.
If LED lighting is used. Generally only a few parameters are needed. Luminous Angle, luminous flux, color rendering