The human eye color and brightness of the light of your resolution is often rather high, considering buying anything . the color difference and changes are very sensitive. Utilizing efficiency and brightness LED constantly improved, and its application could be more and extensively. When LED as array display and display devices, like the human eye for color and brightness of wavelength sensitivity, no separation of have LED evenly phenomenon and affect people's visual effect.
The wavelength and the inhomogeneity of brightness will give people produce uncomfortable becoming. According to the main wavelength, usually LED light intensity, light with brightness, color temperature, working voltage, reverse breakdown voltage several key parameters for testing and break up. LED test and the sorting is LED production process of ones necessary method. At present, it is many LED chips and packaging manufacturers the production capacity for the bottleneck, one more LED chip production and packaging costs important piece.
1, LED the sorting method
LED, are usually two ways of sorting: the the basic test chips for separation, and the second is to packaging good test LED satisfactions.
(1) the test chip satisfactions
LED chips sorting difficult, the cause is the LED chips generally very small size, from 9 mil to 14 mil (0.22-0.35 nm). Such a small chip need microprobe can carry out tests, sorting process requires precise machinery and image recognition system, so that equipment cost becomes very tall, and test speed is very few. Now the LED chips sorting machine test in regards price is 1 million yuan RMB, Taiwan, the test speed every hour in about 10000 canines. If the calculated monthly 25 days, every station sorting machine capacity of 5 KK every fair amount of time.
At present, the test chip sorting have home equity loans methods: a type of method is tested your same machine complete separation, its advantages is reliable, but slowly, productivity is low; Another method is to check out and sorting by two machines completed, test equipment to record each chip position and parameters, then put these data transfer to the sorting equipment, the rapid separation, do this advantage is rapidly, it's weakness is actually low reliability, easy help make matters a mistake, because in the test and separation between two steps usually a substrate thinning and chip the process of separation, too the process, the extension of may disintegrate, local incomplete or local fractured incomplete, would make the actual chip distribution and storage in sorting machine data with discrepancies, cause difficulties searching.
From rise at all solve bottle-neck separation test chip is key to boosting the extension of uniformity. Vehicle extension within the distribution within 2 nm wavelength in, the change of the brightness in within 15%, can will the film of all chip frequently for a (Bin), prolonged as you as along with test of your unqualified chip can be removed, will greatly help the production capacity of the chip and reduce the associated with the microchip. In the uniformity is not very good, also could be to test and the 'unqualified products more' chip areas use inkjet blot out ways of dealing with drop, which quickly to require 'qualified' chip, but so cost is just too high, will put far more of accord with other room requirements as not certification chip waste treatment, and finally a chip cost accounting may be market can't accept point.
(2) LED the separation test
After the encapsulation leds luminous intensity, according towards wavelength, the light and the Angle of test working voltage and sorting. Outcome is LED into lots of the documents (Bin) and category, just to test sorting automatically solution . the chance to set the standard test LED in different Bin packing box. Because those LED to demand much more more, the early sorting machine is 32 Bin, then increase to 64 Bin, there turn into over 72 Bin commercial sorting machine. Even so, points of Bin LED technology index still can't satisfy the fabrication and the demand of the market.
Sorting machine is LED test in a particular workbench electricity flowing down the (such as 20 mA), LED to test, general will instigate a reverse voltage value of this test. The sorting machine now LED test about the price 40 ~ 500000 RMB/set, the test speed every hour in about 18000 dog's. If the 25 days a month, 20 hours every day the working time for this calculation, every station sorting machine capacity of 9 KK launched.
Large screen or other high-end application customers, Resulted in the quality requirements among the higher. Especially in wavelength and brightness on demand consistency extremely strict. If FengZhuangChang LED in chip purchasing for you to put forward strict requirements, the FengZhuangChang in lots of these shipped will find, encapsulation good only a tiny amount of LED products can meet a client requirements, most of the remainder the finish up in the warehouse supply. This situation forced LED FengZhuangChang in purchasing LED chip strict requirement put forward, especially the wavelength, the brightness and table of voltage index; For example, the past to request is + 2 nm wavelength, and is now you'll the + 1 nm, or, within an applications, has proposed + 0.5 nm requirements. So with the chip factory produce big pressure, your chip sales to strict separation previously.
From previously mentioned about LED and LED chip points can rise above the crowd in the analysis, comparative economic method is to test LED satisfactions. But because of the LED various differing kinds of different form, not the form of the now, different size, different light Angle, different customer requirements, different application requirements, the use right require completely through test points LED produced by product separation is tough to operate. Certain to the implementing LED mainly distributed in the few wavelengths segment as well as the brightness for the section area, a FengZhuangChang hard to all customer needs for this various forms and associated with LED. Therefore the key for the problem and return for the extension of MOCVD process, how develop the needed wavelength and brightness LED extension is to reduce the price of consequently point, this is not solved, LED the production capacity of the cost while won't get completely solved. But in the extension of the homogeneous and then search for get control before, far better method can be always to solve rapidly low-cost chip sorting problem.
2, sorting equipment
At present, LED chips sorting equipment testing largely by the us and Japan manufacturers to provide, and LED the sorting equipment testing using the Taiwan region, most manufacturers provide Hong Kong, mainland China can't provide similar equipment brandnames. LED chips sorting machine mainly includes two hardware (machine hand, micro probes and photoelectric tester) along with set of system software, the three parts by different manufacturers with respectively to integrated; And LED the test points, along with the selection machine LED mechanical transmission, storage and parameter test two parts.
3, LED points selection technology development trend
(1) typically the extension of the homogeneous higher level of get control before, r&d rapid cost effective chip separating process and equipment.
(2) utilizing W level power LED technology development, the traditional LED products inspection standard parameters and test method can not meet the needs of the lighting applications, it vital to develop new test standards and methods, including more and lighting related optical subject.
(3) associated with LED systems in life test, developing LED system's long-term performance and life quickly determine evaluation technology.
(4) LED lighting is large current drive to work, it is to submitted higher requirement of the reliability. Traditional way of screening not appropriate LED lighting use high power LED, must develop new screening test method, eliminate early failure is tasted, be sure the reliability belonging to the product.