CN103048605B

CN103048605B - The detection screening technique that a kind of LED is aging

Info

Publication number: CN103048605B
Application number: CN201210561659.5A
Authority: CN
Inventors: 张友贤; 王俊; 樊新军; 吴军
Original assignee: THREE GORGES VOCATIONAL COLLEGE OF ELECTRIC POWER
Current assignee: THREE GORGES VOCATIONAL COLLEGE OF ELECTRIC POWER
Priority date: 2012-12-22
Filing date: 2012-12-22
Publication date: 2015-10-14
Anticipated expiration: 2032-12-22
Also published as: CN103048605A

Abstract

The detection screening technique that a kind of LED is aging, the electric current and voltage that are input to each LED is periodically adjusted by using computer numerical control equipment, the temperature data of each LED is detected by thermocouple temperature measurement instrument, described computer numerical control equipment is according to the temperature data of each LED received and corresponding voltage and/or current value, be depicted as the voltage of linear relationship, temperature funtion curve also shows on a computer display, the data detected are found out underproof LED compared with the threshold value preset and shows over the display, operating personnel are according to the mark that computing machine shows, label screening is carried out to underproof LED, complete the aging detection of LED and screening.The detection screening aging to LED can well be realized by the present invention, improve the safe reliability of equipment.

Description

The detection screening technique that a kind of LED is aging

Technical field

The present invention relates to the detection screening technique that a kind of LED is aging, particularly relating to a kind of detection screening technique by getting rid of the aging LED electrical and technique being existed hidden danger of LED.

Background technology

In high-power LED street lamp illumination, three large key problem in technology are: heat management, driving power and LED performance quality.Front two existing many improvement results, exclusive Section 3 is still and follows forefathers old course and waddle, its present situation is: in the light source be made up of many high-power LED arrays or high-power polycrystalline integrated (IC), reject the LED component of early stage and secondary initial failure, it is always loaded down with trivial details and problem that is headache, LED component is after normality condition test passes, make a final check has been general aging test, but the aging test of routine can only reject the great power LED of part initial failure, helpless to the great power LED of secondary initial failure, this method is also very limited for the short-term effect of rejecting the great power LED of initial failure simultaneously, thus people expect to extend digestion time to reach re-set target, what have even extends to 240 hours by digestion time, but It dones't help the situation at last, the LED of the early stage and secondary initial failure of high-power illumination still constantly occurs (miscellaneous part lost efficacy and inquires in a separate paper), this is for the high-power LED street lamp of costliness, also be difficult to hide with regard to flaw, the difficult attached long-life is real.

At present, the equipment of the performance failure effectively predicted and detect LED does not also exist, and general detection is all use conventional methods to process.In general, LED is aging is exactly adopt high voltage tolerance driving method, and the driving voltage higher than normal drive voltage is acted on LED, and the method is that voltage all high for the multiple voltages needed for driving LED is acted on LED, and provides resistance to tested person to LED.The test of high voltage tolerance driving method can improve the ability detecting the line defct that makes the voltage level that applies can exist the LED of open circuit and detect.High voltage tolerance driving method can reduce the burn-in test time significantly and provide the throughput rate of LED.But be not also applicable to now the special arrangement equipment of LED ageing management, traditional method is the mode adopting manual testing, staff is utilized to carry out burn-in test to each LED, and this mode detect not only for detect the eyes of workman there is injury greatly and also its efficiency detected very low, to work every day 8 hours, each workman detects maximum 5,000 LED every day, and manual detection, when extracting for LED, the pin of its both positive and negative polarity is easily bending ceases to be faithful, and affects the quality of product.

For a change this present situation, then need to look for another way, other Case road.Applicant analyzes from long-term working practice and inspection information, have studied high-power LED illuminating device thrashing mechanism and LED component failure mechanism after investigated this method, take the compensation process outside a series of conventionally test, in order to reject the great power LED of early stage and secondary initial failure, thus improve the reliability of great power LED.

Summary of the invention

Technical matters to be solved by this invention overcomes the deficiencies in the prior art, and provide the detection screening technique that a kind of LED is aging, the method comprises the following steps:

A. LED array to be detected is alignd, make LED negative pole pin and cathode contact sheet good contact, and each contact of computer numerical control equipment output terminal is connected with corresponding each LED positive pole pin, the power supply of positive pole contact and negative pole contact is kept to connect, each contact of thermocouple temperature measurement instrument is contacted with each LED respectively, makes each LED on LED array energising pair array carry out aging;

The rated voltage wherein exported is 24V, rated current exports as 50mA, LED digestion time is 70 minutes, described computer numerical control equipment can adjust the electric current and voltage that are input to each LED as required, and voltage and/or the current value of each output contact can be demonstrated on a computer display, computer numerical control equipment periodically upgrades the voltage and current value demonstrated, and voltage and current value is stored, the LED unit for voltage and/or current value exception can carry out highlighted display over the display;

The input end of described computer numerical control equipment is connected with thermocouple temperature measurement instrument, receive the temperature data from described thermocouple temperature measurement instrument, described computer numerical control equipment, according to the temperature data of each LED received and corresponding voltage and/or current value, is depicted as the voltage of linear relationship, temperature funtion curve showing on a computer display;

B. described computer numerical control equipment periodically detects line by line to described LED array, in described computer numerical control equipment, preset LED start threshold values and shutoff valve value parameter, in detecting line by line, when detecting that LED does not reach described startup threshold values and closes threshold values, explicit identification on a computer display, and the positional information of the LED of mark correspondence is stored;

C. under rated voltage and electric current operating condition, when detecting that LED occurs that pressure drop is abnormal, explicit identification on a computer display, and the positional information of the LED of mark correspondence is stored;

D. run more than 1 hour in rated voltage and electric current and after temperature stabilization, when detecting that the magnitude of voltage of LED is when within 1 hour, front and back difference exceedes the threshold value of setting, explicit identification on a computer display, and the positional information of the LED of mark correspondence stored;

E. after the burn-in test time arrives, according to the positional information stored, the mark of all underproof LED shown over the display, operating personnel are according to the mark that computing machine shows, label screening is carried out to underproof LED, completes the aging detection of LED and screening.

It is more than the core content of the detection screening technique that this LED is aging, it is only a kind of non-aging method of rejecting the early stage and secondary initial failure of great power LED that its meaning is far from, in the same way, analyse in depth, study the generality of failure mechanism, revise by different characteristics, also can be used for selecting of other devices, as the equipment etc. of military use.Little it, substitute aging, save aging human and material resources and time, large it, the safety and reliability of equipment is fundamentally explored in attempt.Certainly, at work, even select certain applications by physical condition also have benifit.The applicant is designing and producing in LED lamp; in addition to the above; the composite graphite temperature-uniforming plate adopting optical mold, heat conduction good, heat pipe and air channel combine or air blast cooling cooling system, the common-mode noise that antistatic, anti-distribution system is introduced and the interference of transition spike and be incorporated to the protection tube etc. of LED.This method once part is used for, in the LED street lamp product of hanging net operation, going through examination in 2 to 3 years, all right.

Accompanying drawing explanation

Fig. 1 is the system architecture diagram of the detection screening technique that a kind of LED of application the present invention is aging.

Embodiment

For making the object, technical solutions and advantages of the present invention clearly, below in conjunction with accompanying drawing, the present invention is described in further detail.

See Fig. 1, the present invention is the detection screening technique that a kind of LED is aging, and the system of application the method is primarily of computer numerical control equipment and thermocouple temperature measurement instrument composition, and the method comprises the following steps:

The unlatching threshold values of LED modules with different colors and close threshold values with different vendor with batch all have difference, all should give rejecting to the LED component exceeding average more than 20%.

After LED energising work, the operating voltage and employing thermocouple temperature measurement instrument measuring tempeature of measuring LED component is adopted by same time interval, the voltage of linear relationship, temperature funtion curve can be depicted as, to deflection curve error reach 20% and above LED component rejected.

After LED light source energising work more than 1 hour and temperature stabilization or rate of temperature change < 5%, measure each LED operating voltage, to exceeding average working voltage value 20% and above LED component is rejected.

Applicant is designing and producing in LED lamp, carries out, except the aging detection screening of LED, these methods below also being adopted to screen, equally also well ensureing the safety and reliability of product except adopting said method.

LED component is placed in fluorine carbon inert fluid, its advantage is that test product can not leave contaminative vestige), under the high/low temperature that specification allows, carry out thermal shock test, heat to assigned temperature and fixed time, repeatedly circulate, repeatedly store, to the stress utilizing LED encapsulation material expansion coefficient and shrinkage ratio difference to produce, make bonding point displacement increase, gold thread (or aluminum steel) fatigue breakdown in advance, to reject the ID phase LED component of the bad easy open circuit of gold thread bonding.LED component production firm is in its LED technology Parameter specifications provided, give the operating temperature range of LED, under the boundary value of its scope, carry out the thermal shock test at interval of 2 hours, 3 the rear rejectings that circulate have damaged and conventional sense parameter, mainly reverse leakage current >=5 μ a, underproof LED component.

The method not enough or supplementary further in above-mentioned condition is placed in silicone oil by LED to heat to 130 DEG C, often falls 2 DEG C-10 DEG C and survey its forward voltage drop under pulse voltage, to obtain this batch of LED vf/TJ model curve, thus rejects flying spot defective products.

In addition, the amphicheirality of LED luminescence and photovoltaic effect can also be utilized, detect under the normal adverse condition used, reject the defective products that LED component PN junction is subject to Organic Pollution; But it is very difficult because extracting faint photogenerated current in strong external electromagnetic field signal.Therefore adopt anti-aliasing filtering, phase lock amplifying technology, faint photogenerated current can be separated from strong neighbourhood noise, to judge and to reject defective products.Adopt the photovoltage of anti-aliasing filtering and lock-in amplify electric circuit inspection LED under 500lx light intensity, reject the LED lower than average photoproduction magnitude of voltage 20%.

Because the discreteness of LED V-A characteristic is very large, the current density on PN junction is often non-uniform Distribution, and this phenomenon is the random variation because of current difference again, adopts face thermometric mode to test under the service condition of setting, rejects high device.The LED matrix arrangement light source of employing face temperature measurer to identical working current carries out thermometric, and due to the random difference of PN junction structure, electric current is line shape, current density raises, and the LED component producing local anomaly (exceeding mean value 20%) temperature rise is rejected.

In the light source of same batch of LED assembling, reject the device of red shift of wavelength.Adopt spectral wavelength tester to test the LED in same batch of LED and the 4th article after thermal oscillation process, to wavelength increase by 20% and above LED rejected.

The foregoing is only the preferred embodiments of the present invention, be not limited to the present invention, for a person skilled in the art, the present invention can have various modifications and variations.Within the spirit and principles in the present invention all, any amendment done, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.

Claims

1. the detection screening technique that LED is aging, is characterized in that comprising the following steps:

Repeatedly circulate under LED component being placed in the high/low temperature of specification permission, repeatedly store, or LED is placed in fluorine carbon inert fluid carries out thermal shock test, to the stress utilizing LED encapsulation material expansion coefficient and shrinkage ratio difference to produce, bonding point displacement increase, gold thread or aluminum steel is made to shift to an earlier date fatigue breakdown, to reject the bad initial failure product easily causing LED to open a way of gold thread bonding;