The human eye color and brightness of the light belonging to the resolution rrs incredibly high, you will the color difference and changes are sensitive. With the efficiency and brightness LED constantly improved, and its application one is more and more widely. When LED as array display and display devices, as the human beings eye for color and brightness of wavelength sensitivity, no separation of have LED evenly phenomenon and affect people's visual impression.
The wavelength and the inhomogeneity of brightness may give people produce uncomfortable encounter. 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 separation. LED test as well as the sorting is LED production process of an necessary operation. At present, it is many LED chips and packaging manufacturers the production capacity on the bottleneck, one more LED chip production and packaging costs important component.
1, LED the sorting method
LED, the two ways of sorting: the the basic test chips for separation, and second is to packaging good test LED satisfactions.
(1) test chip satisfactions
LED chips sorting difficult, the cause is the LED chips generally smaller size, from 9 mil to 14 mil (0.22-0.35 nm). With this small chip need microprobe can engage in tests, sorting process requires precise machinery and image recognition system, which makes equipment cost becomes very tall, and test speed is reserved. Now the LED chips sorting machine test about the price is one million yuan RMB, Taiwan, test speed on an hourly basis in about 10000 properly trained canines. If the calculated monthly 25 days, every station sorting machine capacity of 5 KK every 4 weeks.
At present, the test chip sorting have two types of methods: a kind of method is tested by the same machine complete separation, its advantages is reliable, but slowly, productivity is low; Another way is for a test run 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, but its weakness is pretty low reliability, easy to create mistake, because in the test and separation between two steps making sure substrate thinning and chip the associated with separation, also in the process, the extension of may disintegrate, local incomplete or local fractured incomplete, helps make the actual chip distribution and storage in sorting machine data with discrepancies, cause difficulties searching.
From mechanism at all solve bottle-neck separation test chip important to improving the extension of uniformity. Within the area . extension of this distribution within 2 nm wavelength in, the change of the brightness in within 15%, can will the film of all chip in substitution for a (Bin), as long as together with test of the unqualified chip can be removed, will greatly boost your employees production capacity of the chip decrease the cost of the microchip. In the uniformity is no longer that good, can also be used for a test run and the 'unqualified products more' chip areas use inkjet blot out associated with dealing with drop, which quickly to need 'qualified' chip, but so do cost as well high, will put lots of accord to other room requirements as not certification chip waste treatment, and finally a chip cost accounting may be market can't accept location.
(2) LED the separation test
After the encapsulation leds luminous intensity, according to the wavelength, the sunshine and the Angle of test working voltage and sorting. It makes sense LED into a lot among the documents (Bin) and category, and then test sorting automatically in accordance with the chance to set the standard test LED in different Bin packing box. Because those LED to demand as well as more, their early sorting machine is 32 Bin, then increase to 64 Bin, there have started over 72 Bin commercial sorting machine. Even so, points of Bin LED technology index still can't match the production and also the demand from the market.
Sorting machine is LED test in a particular workbench electricity flowing down the (such as 20 mA), LED to test, general will do a reverse voltage value with the test. The sorting machine now LED test about the price 40 ~ 500000 RMB/set, the test speed an hour in about 18000 canine. If the 25 days a month, 20 hours on a regular basis the working time of this calculation, every station sorting machine capacity of 9 KK introduced.
Large screen or other high-end application customers, Led to the quality requirements within the higher. Specially in wavelength and brightness at the moment consistency is definitely strict. If FengZhuangChang LED in chip purchasing decided not to put forward strict requirements, the FengZhuangChang in a lot of these shipped will find, encapsulation good only not many LED numerous meet a client requirements, many of the rest of the will end up in the warehouse catalog. 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 which is now essential for the + 1 nm, or, in some applications, has proposed + 0.5 nm requirements. So with the chip factory produce large amount of pressure, a chip sales to strict separation before you start.
From previously mentioned about LED and LED chip points can be observed in the analysis, comparative economic way is to test LED satisfactions. But because of the LED various kinds of different form, not the model of the now, different size, different light Angle, different customer requirements, different application requirements, utilize of right to help completely through test points LED created from product separation is hard operate. And now the employing LED mainly distributed typically the few wavelengths segment as well as the brightness in the section area, a FengZhuangChang hard to prepare all customer needs of the numerous forms and types of Distributed. So the key to the problem and get back on the extension of MOCVD process, ways to grow the appropriate wavelength and brightness LED extension would reduce eliminate the cost of the key point, difficulty is not solved, LED the production capacity of this cost and nevertheless won't get completely solved. But in the extension for the homogeneous amount of get control before, efficient method for you to solve rapidly low-cost chip sorting wrong doing.
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 together with Taiwan region, most manufacturers provide Hong Kong, mainland China can't provide similar equipment clothing manufacturers. LED chips sorting machine mainly includes two hardware (machine hand, micro probes and photoelectric tester) and a set of system software, the three parts by different manufacturers with respectively to integrated; And LED the test points, even the selection machine LED mechanical transmission, storage and parameter test two parts.
3, LED points selection technology development trend
(1) in the extension for the homogeneous a higher level get control before, r&d rapid small fee chip separating process and equipment.
(2) using the W level power LED technology development, the traditional LED products inspection standard parameters and test method can not meet the requirements the lighting applications, it is recommended to develop new test standards and methods, including more and lighting related optical reports.
(3) your market LED systems in life test, developing LED system's long-term performance and life quickly determine evaluation development.
(4) LED lighting is either large current drive to work, it is to submit higher require for the durability. Traditional way of screening not appropriate LED lighting use high power LED, must develop new screening test method, eliminate early failure is tasted, guarantee the reliability belonging to the product.