Led street light project

With the constant improvement of the efficiency and brightness of LED, the scope of its application is more and more widely. When the LED array as a display and solar street lamps 。 jschindo。 com】 Devices, due to the sensitivity of the human eye to color the wavelength and brightness, without the LED variable separation can produce

with the constant improvement of the efficiency and brightness leds, the scope of its application is more and more widely. When using light-emitting diodes as array displays and solar street lamps [ 。 jschindo。 com] Devices, due to the sensitivity of the human eye to color the wavelength and brightness with leds would produce uneven phenomenon, influence people's visual effect. The wavelength and brightness of the uneven can give a person uncomfortable feeling. This is all of the led street lamp manufacturers don't want to see, is that people cannot accept. Light-emitting diodes (leds) usually test and classification, according to several key parameters such as dominant wavelength, luminous intensity, light, color temperature, working voltage, reverse breakdown voltage, etc. Light-emitting diodes (leds) testing and sorting is the indispensable process in the production of light-emitting diodes (leds). 一个。 LED light-emitting diode sorting method classification there are two ways: one is based on the chip testing and classification, the other is a test and classification of encapsulation of LED. ( 1) Chip test and classification of the classification of the light emitting diode chip is very difficult, mainly because of the size of the light emitting diode chip is very small, usually from 9 mm to 14 mm ( 0. 22 - 0. 35 nm) 。 Such small chip microprobe is required to complete testing, and sorting process requires precision machinery and image recognition system, which makes the equipment cost is very high, the test speed is limited. At present, there are two kinds of chip testing and sorting methods: one is testing and sorting work by the same machine, with high reliability, the advantages of low speed, low production capacity; Another way is to test and classification performed by two machines. Test equipment to record the location of each chip and parameters, and then the data sent to the sorting equipment. The advantages of rapid separation is rapid, but defect is low reliability and error-prone, because between test and separation step is usually a thinned substrate and separation process of chip. In the process, epitaxial wafer can rupture, section or part of the bursts, which makes the actual distribution of chip and the data stored in the inconsistent classification machine, which may lead to a difficult classification. Fundamentally solve the problem of chip testing and sorting bottleneck is the key to improve the uniformity of epitaxial wafer. If epitaxial wafer wavelength distribution within the 2 nm, and brightness changes within + 15%, are all the chips on the wafer can be classified into a container. As long as through test unqualified chip, chip capacity will increase greatly, the chip will reduce the cost. In the case of uniformity is not very good, also can be used to test and put & other many unqualified products &; Through inkjet coating processing chip area, so as to achieve the desired effect. Qualified &; Chip, but the cost is too high, many meet the requirements of the other rooms chips will be deemed to be unqualified, finally calculate the chip cost in the market may be in an unacceptable level. ( 2) Light-emitting diodes (leds) after testing and classification packaging of leds can be according to the wavelength, luminous intensity, light Angle test and classification, working voltage, etc. Therefore, leds are divided into many locker and categories, then test separator automatically according to the test standard of setting will be led into different locker. As people more and more high to the requirement of light-emitting diodes (leds), early sorting machine is 32 bin, then increased to 64 bin, now has 72 bin sorting machine for commercial use. Even so, Lin LED technology indicators still cannot meet the needs of production and market.