CN102226724A - Detection method of junction temperature of chip of LED illumination lamp having built-in power switching circuit. - Google Patents
Detection method of junction temperature of chip of LED illumination lamp having built-in power switching circuit. Download PDFInfo
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- CN102226724A CN102226724A CN 201110071088 CN201110071088A CN102226724A CN 102226724 A CN102226724 A CN 102226724A CN 201110071088 CN201110071088 CN 201110071088 CN 201110071088 A CN201110071088 A CN 201110071088A CN 102226724 A CN102226724 A CN 102226724A
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Abstract
The invention discloses a detection method of junction temperature of a chip of an LED illumination lamp having a built-in power switching circuit. According to detection method provided in the invention, the junction temperature of the LED chip in the LED illumination lamp is determined according to a law of variation with temperature of a forbidden bandwidth of an LED material and a temperature rising rule of packaged chip in the lamp after the power off of the lamp. Besides, a concrete measuring process and a measuring effect are provided in the invention. Advantaged of the method provided in the invention are as follows: LED products on the market can be detected directly, wherein the LED products always have a built-in power switching circuit that enables a requirement not to be met, wherein the requirement is required by a conventional method and is required to load pulse power supply to the lamp. In other measurement methods, specific external driving power is needed but does not match the built-in power switching circuit; the above-mentioned problem is solved according to the invention. Therefore, the direct detection to the LED lamp products without any change condition can be realized.
Description
Technical field
The present invention relates to the detection method of semiconductor light-emitting-diode (LED) junction temperature of chip, particularly a kind of detection method of GaN base white light LED lighting device chips junction temperature of built-in power-switching circuit.
Background technology
LED gradually appears in " semiconductor lighting engineering " owing to its brightness height, characteristics such as the life-span is long, reliability is high, easy driving.At present, great power LED has replaced traditional devices in most illumination is used, become the semiconductor lighting device of main flow.LED lamp group is an international trend, China is taking its place in the front ranks of the world with LED electricity-saving lamp application facet, it on Beijing Olympic concentrated reflection, and on Shanghai World's Fair, obtained further development, under the background of high speed development, heat stability test and the heat dissipation problem of LED receive much attention, and the junction temperature of chip in the light fixture is an important parameter.Yet effective detection technique of the led chip junction temperature in the LED light fixture has not caught up with, but this technology is again the necessary guarantee that the LED electricity-saving lamp obtains quick application development.Particularly LED light fixture product often all is the built-in power change-over circuit, carries out effective junction temperature of chip with regard to being difficult to match for the outside special burst power supply of the light fixture of these built-in circuit and measures, and does not also have good way head it off at present.
Junction temperature is the key element of reliability measurement during LED device engineering is used as the important parameter of weighing a LED device performance quality, also is the major parameter in the LED testing product.Can be used for the research in LED light fixture reliability and serviceable life to the measurement of junction temperature, therefore, the junction temperature of accurately measuring semiconductor light-emitting-diode has important and practical meanings.Up till now for this reason, the product of all kinds of detection junction temperatures both domestic and external is to utilize electrical properties, thermal property, luminosity and colorimetry character to measure junction temperature mostly.At present, the method for measuring the LED junction temperature has following several usually: 1, and forward voltage method: utilize the temperature effect of LED electronic transport, under the condition of steady current, obtained the linear relationship of forward voltage and junction temperature; 2, pin method: be the pin temperature of utilizing LED, try to achieve junction temperature by dissipated power and thermal resistivity; 3, blue Bai Bifa: being a kind of non-contacting measuring method, is to utilize in the white light LEDs electroluminescent spectrum power ratio of blue light and white light to measure junction temperature; 4, the infrared photography method: be the method that the measurement junction temperature used always distributes, but its cost height, speed is slow, and device is the state that does not encapsulate or break a seal.But these methods substantially all need the pulse current place in circuit, as the usefulness of the calibration of measured physics amount and temperature relation.For single tube LED, this point is not difficult to apply, but for the light fixture said method big difficulty is arranged.At present a large amount of light fixtures is all built-in power-switching circuit, therefore outside pulse current can't insert, and has so just hindered effective application of these methods.But all control circuit is made into light fixture mostly as product on the market, and the light fixture junction temperature can reflect the life-span of LED device in the light fixture, the led chip junction temperature is very with practical value in the light fixture of built-in power change-over circuit so can realize measuring.We directly carry out the measurement of junction temperature of chip in the light fixture under the built-in power-switching circuit normal mode of operation of light fixture, so we can expand to whole LED light fixtures from led chip with measuring object.At the LED lighting field, this is extremely important.
Summary of the invention
Purpose of the present invention is exactly to propose a kind of precision can reach 2 degree include the LED lighting chips junction temperature of power-switching circuit with interior detection method.
The present invention judges the junction temperature of chip in the LED light fixture under the normal operating conditions according to moving of its luminous peak position.
Concrete technical scheme of the present invention is as follows:
1, detection system is as shown in Figure 1: the LED light fixture product that comes into the market is connected on the terminal block of switch by its using method, terminal block directly inserts on the 220V civil power, switch on the terminal block is energized once closed lamp, thereby enter normal luminance, the constant-current source circuit that the 220V alternating current is converted to LED light fixture needs is all built-in in LED light fixture product.Computing machine is controlled spectrometer by USB interface, and the light that the LED light fixture is sent out introduces spectrometer through the optical fiber coupling.Spectrometer just is adjusted to the state of measure spectrum before the terminal block Closing Switch, guarantees that like this this system can detect the spectrum that the LED light fixture begins luminous moment more conveniently, and measures the spectrum when junction temperature of chip is stablized in the LED light fixture constantly.
2, product to be measured is calibrated:
2.1 the luminescent spectrum peak was definite when the light fixture junction temperature was identical with environment temperature: in first second of opening light fixture, gather spectrum fast, the spectra collection time interval is less than 30 milliseconds, get constant substantially 10 spectrum of the most close light fixture open-interval of spectral signature, from 10 luminous peak position λ that wherein obtain
1,1, λ
1 .2, λ
1,3, λ
1,4, λ
1,5, λ
1,6, λ
1,7, λ
1,8, λ
1,9, λ
1,10Linear extrapolation obtains the luminous peak position λ that light fixture is opened moment
1
2.2 according to said method, but light fixture is placed in the constant temperature oven of alternating temperature, changes the temperature in the constant temperature oven, from room temperature T
0Changing to 100-300 degree centigrade does not wait, decide according to light fixture junction temperature height to be measured, the junction temperature temperature that the upper limit of the alternating temperature of constant temperature oven should may reach greater than light fixture, per approximately 10 degree for interval variation once, record the luminous peak position λ under different calorstat temperature T degrees centigrade
1Value λ
1(T), then by then by λ
1And relation has just obtained the calibration curve of the product junction temperature measurement of surveying between the T: Δ λ=λ
1(T)-λ
1(T
0) with the relation curve of T
3, allow light fixture be in off position, after fully being dispelled the heat, it guarantees that junction temperature got back to the environment temperature of measuring.Opening spectrometer makes it be in acquisition state, closed again terminal block switch, light fixture enters duty, in preceding 1 second, the spectra collection of spectrometer is less than 30 milliseconds interval time, Measuring Time can be got 1-100 about second greater than the time interval of gathering spectrum after 5 minutes, records light fixture always and reaches and stablize till the junction temperature temperature.
4, so far spectrometer has write down a large amount of spectroscopic datas, the background spectrum that we do not open light fixture (spectral signature of no LED lamp luminescence) is to the moment of the spectrum that has LED lamp luminescence spectral signature, think the initial moment of lamp luminescence, get 10 spectrum of spectral signature the most close constant substantially electric power starting time, from 10 luminous peak position λ that wherein obtain
1,1, λ
1 .2, λ
1,3, λ
1,4, λ
1,5, λ
1,6, λ
1,7, λ
1,8, λ
1,9, λ
1,10Linear extrapolation obtains the luminous peak position λ that light fixture is opened moment
1Get 10 of the LED lamp luminescence spectrum of the junction temperature in writing down after stable, make 10 luminous peak position λ
2,1, λ
2 .2, λ
2,3, λ
2,4, λ
2,5, λ
2,6, λ
2,7, λ
2,8, λ
2,9, λ
2,10, the mean value of getting 10 values is λ
2
5, by λ
2With λ
1Difference Δ λ, make light fixture when just starting working and the junction temperature discrepancy delta T after stable.Just can determine junction temperature T according to the calibration curve of determining in the step 2, because we get is that light fixture has just begun the spectrum when luminous, so light fixture junction temperature at that time is exactly room temperature T
0, therefore the junction temperature T that can draw under the light fixture duty is T
0+ Δ T.In the light fixture of the concrete case study on implementation of this patent, this calibration curve can be by following equation expression:
T-T
0＝cΔλ+dΔλ
2
c＝20.9±0.2，d＝-0.63±0.2
This calibration curve will depend on the material behavior of emitting led chip in the light fixture, for different light fixtures different calibration curves often be arranged for this reason.But for the same a collection of product of same producer, led chip often all is identical, so its calibration curve also all is identical, therefore need not in such cases each measured light fixture is all calibrated.
The present invention has following advantage:
1, this method has overcome the difficulty that conventional luminous peak position drift method must adopt the pulse power and then can not measure the LED light fixture that the built-in power change-over circuit is arranged, the power supply mode that carries with the LED light fixture replaces the pulse power to calibrate, and makes it go for the various light fixture products on the market and the light fixture product in different manufacturers source.
2, this method has overcome conventional electrical method and has determined deficiency in the junction temperature, interconnective circuit is irrelevant between each single tube of this method and light fixture, and is also irrelevant to the encapsulation state of LED single tube with light fixture, is suitable for the light fixture product in different types of light fixture product and different manufacturers source for this reason.
3, this method has overcome infrared thermal imagery method and Raman measuring method and has determined deficiency in the junction temperature.Infrared thermal imagery requires led chip must directly expose in measuring light path and does not have blocking of other encapsulation transparencies, and this method is not limited; This method does not have led chip in the Raman method to gather the very near requirement of object lens distance with Raman signal yet.Any optical package form that for this reason is suitable for the light fixture product.
Description of drawings
Fig. 1: detection system synoptic diagram.
Spectrogram when Fig. 2: LED has just started, about 460nm is the LED glow peak, about 600nm is fluorescence peak.This patent is mainly paid close attention to the LED glow peak, and all peak position wavelength of mentioning in the patent all are meant the peak position wavelength of 460nm left and right sides LED glow peak.
Fig. 3: LED lamp luminescence peak position is benchmark along with the variation diagram of conduction time with the first spectrum peak position that collects, and is scanning fast in first minute, and back 29 minutes is slow scanning.
Embodiment
The present invention is described in further detail below by embodiment and accompanying drawing.
1, tested LED light fixture energized is luminous, LED light fixture rated power 140W, 220 volts of rated voltages adopt civil power that light fixture is powered in this example, and environment temperature is 23 degrees centigrade during measurement.By optical fiber the light fixture issued light is directly guided to spectrometer inside.Regulate light path, make signal that spectrometer collects on a suitable intensity, as shown in Figure 2.
2, at first regulate the position of fiber spectrum instrument probe, make signal that spectrometer collects on a suitable intensity.Powered-down, it is luminous to extinguish LED, waits for 10 minutes, makes lamp temperatures be returned to environment temperature.Opening power makes LED light fixture operate as normal once more.The method of describing in the application invention content 2, in first second of opening light fixture, gather spectrum fast, the spectra collection time interval is less than 30 milliseconds, get 10 spectrum of spectral signature the most close constant substantially electric power starting time, to its glow peak bit linear extrapolation, obtain the luminous peak position λ that light fixture is opened moment
1(T
0), the luminous peak position wavelength that obtains later all is and λ
1(T
0) relatively.
3, but light fixture is placed in the constant temperature oven of alternating temperature, change the temperature in the constant temperature oven, from room temperature T
0Change to 100 degrees centigrade, per 10 the degree for interval variation once, according to said method, record the luminous peak position λ under the different calorstat temperature T
1Value λ
1(T), then by λ
1And relation has just obtained the calibration curve of the product junction temperature measurement of surveying between the T: Δ λ=λ
1(T)-λ
1(T
0) with the relation curve of T, the calibration curve of sample is in this example:
T-T
0＝cΔλ+dΔλ
2
c＝20.9±0.2，d＝-0.63±0.2
4, allow light fixture be in off position, after fully being dispelled the heat, it guarantees that junction temperature got back to the environment temperature of measuring, open spectrometer and make it be in acquisition state, closed again terminal block switch, light fixture enters duty.In this example, in the 1st second of turning on light, spectrometer begins image data with the interval less than 30 milliseconds, and Measuring Time is taken as 30 seconds greater than the time interval of gathering spectrum after 5 minutes, until the 30th minute, record till the stable junction temperature temperature of light fixture.
5, from the spectral line of spectrometer record, get 10 initial spectral lines, according to the method peak position of these 10 spectral lines, extrapolated at the luminous peak position λ of LED light fixture constantly that turns on light
1, get again 10 the LED lamp luminescence spectrum of the junction temperature in writing down after stable, the mean value of getting its peak position obtains the luminous peak position λ of stable back LED
2, find λ
2With respect to λ
1Red shift 2nm, the calibration curve that substitution obtained just now, can get the LED light fixture in work after stable, junction temperature 39 degree that rise because environment temperature is 23 degree, are exactly 62 to spend so stablize junction temperature.Obtained to be built-in with the junction temperature of led chip in the light fixture of change-over circuit.
Aforesaid embodiment is only in order to illustrate technological thought of the present invention and characteristics; its purpose is to make those of ordinary skill in the art can understand content of the present invention and implements according to this; the scope of this patent also not only is confined to above-mentioned specific embodiment; be all equal variation or modifications of doing according to disclosed spirit, still be encompassed in protection scope of the present invention.
Claims (1)
1. the detection method of the GaN of built-in power change-over circuit base white light LED lighting device chips junction temperature is characterized in that may further comprise the steps:
A makes LED luminous tested LED light fixture energized, by optical fiber the light fixture issued light is directly guided to spectrometer inside;
B is divided into two sections with Measuring Time, and first section is the junction temperature fast rise phase, and this time period, second section was after after light fixture is opened 5 minutes, to obtain initial spectrum and finish spectrum to be used for the measured chip junction temperature in these two periods in first second that light fixture is opened;
C gathers spectrum fast in the very first time section of opening light fixture, the spectra collection time interval is got 10 spectrum of spectral signature the most close constant substantially electric power starting time less than 30 milliseconds, from 10 luminous peak position λ that wherein obtain
1,1, λ
1 .2, λ
1,3, λ
1,4, λ
1,5, λ
1,6, λ
1,7, λ
1,8, λ
1,9, λ
1,10, first has the luminescent spectrum characteristic spectrum to obtain peak position λ constantly when obtaining the light fixture unlatching by this 10 peak position values linear extrapolation
1
D according to said method, but places light fixture in the constant temperature oven of alternating temperature, changes the temperature in the constant temperature oven, from room temperature T
0Change to 100-300 degree centigrade and do not wait, decide according to light fixture junction temperature to be measured height, the junction temperature temperature that the upper limit of constant temperature oven alternating temperature should may form greater than light fixture, per approximately 10 degree be interval variation once, record the luminous peak position λ in the different calorstat temperature T moment
1Value λ
1(T), then by λ
1And relation has just obtained the calibration curve of the product junction temperature measurement of surveying, Δ λ=λ between the T
1(T)-λ
1(T
0) with the relation curve of T;
E opened in second period of light fixture, this moment the LED light fixture operate as normal to junction temperature of chip change to stablely, measure 10 of LED lamp luminescence spectrum after stable, desirable 1-100 of the time interval does not wait second, makes 10 luminous peak position λ
2,1, λ
2 .2, λ
2,3, λ
2,4, λ
2,5, λ
2,6, λ
2,7, λ
2,8, λ
2,9, λ
2,10, the mean value of getting 10 values is λ
2
By λ
2With λ
1Difference Δ λ and calibration curve, make when energising just and the junction temperature discrepancy delta T behind the steady operation; And the light fixture junction temperature is exactly operating ambient temperature T when just having switched on
0Thereby, can draw the junction temperature T under the light fixture duty
0+ Δ T.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103267588A (en) * | 2013-06-05 | 2013-08-28 | 常州工学院 | Junction temperature testing device and junction temperature testing method based on temperature variation of LED (light-emitting diode) relative spectrum |
| CN111982340A (en) * | 2020-08-28 | 2020-11-24 | 常州工学院 | Non-contact LED junction temperature measuring method and device |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20080205482A1 (en) * | 2007-02-23 | 2008-08-28 | Cao Group, Inc. | METHOD AND TESTING EQUIPMENT FOR LEDs AND LASER DIODES |
| CN101614592A (en) * | 2009-07-24 | 2009-12-30 | 中国科学院上海技术物理研究所 | A kind of detection method of LED lighting chips junction temperature |
| CN101699235A (en) * | 2009-11-06 | 2010-04-28 | 中山大学 | Analysis and test system and test method for junction temperature of semiconductor lamp |
| CN101701854A (en) * | 2009-11-18 | 2010-05-05 | 中国科学院上海技术物理研究所 | Method for detecting junction temperature of chip of LED lamp |
-
2011
- 2011-03-23 CN CN 201110071088 patent/CN102226724A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20080205482A1 (en) * | 2007-02-23 | 2008-08-28 | Cao Group, Inc. | METHOD AND TESTING EQUIPMENT FOR LEDs AND LASER DIODES |
| CN101614592A (en) * | 2009-07-24 | 2009-12-30 | 中国科学院上海技术物理研究所 | A kind of detection method of LED lighting chips junction temperature |
| CN101699235A (en) * | 2009-11-06 | 2010-04-28 | 中山大学 | Analysis and test system and test method for junction temperature of semiconductor lamp |
| CN101701854A (en) * | 2009-11-18 | 2010-05-05 | 中国科学院上海技术物理研究所 | Method for detecting junction temperature of chip of LED lamp |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103267588A (en) * | 2013-06-05 | 2013-08-28 | 常州工学院 | Junction temperature testing device and junction temperature testing method based on temperature variation of LED (light-emitting diode) relative spectrum |
| CN103267588B (en) * | 2013-06-05 | 2015-04-01 | 常州工学院 | Junction temperature testing method based on temperature variation of LED (light-emitting diode) relative spectrum |
| CN111982340A (en) * | 2020-08-28 | 2020-11-24 | 常州工学院 | Non-contact LED junction temperature measuring method and device |
| CN111982340B (en) * | 2020-08-28 | 2022-03-08 | 常州工学院 | Non-contact LED junction temperature measuring method and device |
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Application publication date: 20111026 |