CN109596962A - The method for testing junction temperature of LED light - Google Patents
The method for testing junction temperature of LED light Download PDFInfo
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- CN109596962A CN109596962A CN201811423223.3A CN201811423223A CN109596962A CN 109596962 A CN109596962 A CN 109596962A CN 201811423223 A CN201811423223 A CN 201811423223A CN 109596962 A CN109596962 A CN 109596962A
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- led light
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- junction temperature
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/26—Testing of individual semiconductor devices
- G01R31/2607—Circuits therefor
- G01R31/2632—Circuits therefor for testing diodes
- G01R31/2635—Testing light-emitting diodes, laser diodes or photodiodes
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Abstract
The present invention provides a kind of method for testing junction temperature of LED light, comprising the following steps: uses Calibrated current lightening LED lamp, LED light is made to reach thermal steady state under scheduled environment temperature, acquire the voltage value at LED light both ends；Change environment temperature, LED light is made to reach thermal steady state under conditions of varying environment temperature, acquires LED light both ends corresponding voltage value at different ambient temperatures；Linear fit is carried out according to the voltage value at the LED light both ends measured at a temperature of the varying environment temperature and varying environment in above-mentioned steps, obtains the relationship calibration curve of LED light junction temperature and voltage；S4, constant acceleration electric current lightening LED lamp is used at a temperature of acceleration, after LED light reaches thermal steady state, accelerate current switching at the pulse current of Calibrated current constant, the voltage value at LED light both ends is measured, and junction temperature of the LED light in the case where accelerating temperature and accelerating current condition is calculated according to the calibration curve.
Description
Technical field
The present invention relates to a kind of method for testing junction temperature of LED light.
Background technique
The life prediction and fail-safe analysis of LED illumination product generally use accelerating lifetime testing experiment and complete, LED illumination
The environmental stress that product is subject in practical applications is complex, and the resultant effect of these stress affects the use longevity of product
Life.And it is related to the accelerated life test of temperature, the accelerated stress in LED lamp is applied to as environment temperature, but actually shadow
The principal element for ringing the LED lamp service life is junction temperature.And existing method for testing junction temperature, it only considered a kind of this stress of environment temperature
Factor, and test method low efficiency.
Summary of the invention
In order at least solve one of the technical problems existing in the prior art, the present invention provides a kind of junction temperatures of LED light
Test method, method includes the following steps:
S1 makes LED light reach thermostabilization shape under scheduled environment temperature using constant Calibrated current lightening LED lamp
State, the environment temperature when LED light reaches thermal steady state under the conditions of Calibrated current are the junction temperature of LED light, acquire LED light
The voltage value at both ends；
S2 changes environment temperature, and LED light is made to reach thermal steady state under conditions of varying environment temperature, acquires LED light
Both ends corresponding voltage value at different ambient temperatures,
S3, according to the LED light both ends measured at a temperature of the varying environment temperature and varying environment in step S1 and S2
Voltage value carries out linear fit, obtains the relationship calibration curve of the LED light junction temperature and voltage；
S4 uses constant acceleration electric current lightening LED lamp, when LED light reaches thermostabilization shape under conditions of accelerating temperature
After state, by constant acceleration current switching at the pulse current of Calibrated current, the voltage value at LED light both ends is measured, and according to step
The relationship calibration curve of the LED light junction temperature and voltage that measure in rapid S3 is calculated LED light and is accelerating temperature and accelerating current bar
Junction temperature under part.
LED junction temperature measurement of the invention first passes through constant Calibrated current and tests out different junction temperatures and LED voltage
Corresponding relationship obtains the relationship calibration curve of LED light junction temperature and voltage by linear fit, is accelerating temperature later and is accelerating electricity
LED light is set to reach thermal steady state under the dual stress of stream, by the constant pulse current for accelerating current switching into Calibrated current,
The junction temperature of LED light is calculated in conjunction with above-mentioned calibration curve and by the voltage at the LED light both ends measured.The present invention can measure
Junction temperature of the LED light in different acceleration temperature and under accelerating current condition, improves testing efficiency.
According to one embodiment of present invention, the value range of the Calibrated current is less than LED light rated current
5%.
According to one embodiment of present invention, the value of the Calibrated current is 1mA.
According to one embodiment of present invention, in the step S4, the pulse width of Calibrated current is less than 10ms and is greater than
0。
According to one embodiment of present invention, in the step S3, according to the varying environment temperature in step S1 and S2 with
And the voltage value and combination formula V at the LED light both ends measured at a temperature of varying environmentF=-A1×t+B1Linear fit is carried out,
Middle A1, B1 are constant, VFFor the forward voltage at LED light both ends, t is the junction temperature of LED light.
According to one embodiment of present invention, LED light is placed in insulating box in test process, the environment temperature is
Temperature in insulating box.
According to one embodiment of present invention, by changing the temperature in insulating box, make LED light in varying environment temperature
Under the conditions of reach thermal steady state.
According to one embodiment of present invention, the difference of the varying environment temperature is 20 DEG C.
According to one embodiment of present invention, LED light is made to keep at least 30 under each environment temperature in test process
Minute.
Detailed description of the invention
Fig. 1 is the test method flow chart of one embodiment of the invention；
Fig. 2 is the schematic diagram of the calibration curve after the linear fit of one embodiment of the invention.
Specific embodiment
In order to make the objectives, technical solutions, and advantages of the present invention clearer, below in conjunction with attached drawing and specific implementation
Example, the present invention will be described in further detail.It should be appreciated that specific embodiment described herein is only to explain this hair
It is bright, but not to limit the present invention.
The present invention provides a kind of test methods of LED light junction temperature, as shown in Figure 1, the described method comprises the following steps:
S1 makes LED light reach thermal steady state under scheduled environment temperature using constant Calibrated current lightening LED lamp, described
Environment temperature when LED light reaches thermal steady state under the conditions of Calibrated current is the junction temperature of LED light, acquisition LED light both ends
Voltage value；S2 changes environment temperature, and LED light is made to reach thermal steady state under conditions of varying environment temperature, acquires LED light
Both ends corresponding voltage value at different ambient temperatures；S3, according to the varying environment temperature and difference ring in step S1 and S2
The voltage value at the LED light both ends measured at a temperature of border carries out linear fit, obtains the relationship calibration of the LED light junction temperature and voltage
Curve；S4 is accelerating the lower using constant acceleration electric current lightening LED lamp of temperature, will after LED light reaches thermal steady state
Constant acceleration current switching measures the voltage value at LED light both ends, and survey according in step S3 at the pulse current of Calibrated current
Knot of the LED light in the case where accelerating temperature and accelerating current condition is calculated in the relationship calibration curve of the LED light junction temperature and voltage that obtain
Temperature.In step s 4, the pulse width of the Calibrated current is less than 10ms and is greater than 0.
LED junction temperature measurement of the invention first passes through constant Calibrated current and tests out different junction temperatures and LED voltage
Corresponding relationship obtains the relationship calibration curve of LED light junction temperature and voltage by linear fit, is accelerating temperature later and is accelerating electricity
LED light is set to reach thermal steady state under the dual stress of stream, by the constant pulse current for accelerating current switching into Calibrated current,
The junction temperature of LED light is calculated in conjunction with above-mentioned calibration curve and by the voltage at the LED light both ends measured.The present invention can measure
Junction temperature of the LED light in different acceleration temperature and under accelerating current condition, improves testing efficiency.
According to one embodiment of present invention, in step sl, the value range of the electric current of the calibration is less than LED light
The 5% of rated current.Using the Calibrated current of numerical value very little, Calibrated current can ignore the self-heating effect of LED light, can
Junction temperature to think this thing LED light sample is consistent with environment temperature.When set environment temperature is T1, when LED light reaches hot steady
Collected voltage V1 is the LED light corresponding section voltage value V1 at junction temperature T1 after determining state.The thermostabilization of the LED light
State refers to that LED light works at least 30 minutes states achieved at ambient.
According to one embodiment of present invention, LED light sample is placed in insulating box, the environment temperature T1 is constant temperature
The temperature set in case.The Calibrated current that the LED light is passed through is 1mA, and LED light is fixed in the insulating box that temperature is T1 30 points
Clock keeps LED substantially stabilized and reaches hot stable state.
According to one embodiment of present invention, in step s 2, the temperature changed in environment temperature, that is, insulating box is followed successively by
T2, T3 ... Tn repeat step S1, obtain LED light sample corresponding section voltage value at different junction temperatures (T2, T3 ... Tn)
V2、V3……Vn。
In step s3, corresponding section voltage value under the different junction temperatures measured according to above-mentioned steps S1 and S2, and according to public affairs
Formula VF=-A1×t+B1It is fitted in advance, obtains LED light junction temperature and saves the linear fit result of voltage as junction temperature and economize on electricity
The relationship calibration curve of pressure, the curve are denoted as L0, as shown in Figure 2.Wherein A1, B1 are constant, VFFor the forward direction electricity at LED light both ends
Pressure, t are the junction temperature of LED light.
In step s 4, the acceleration temperature is environment temperature locating for LED light, the acceleration in accelerated life test
Electric current is the electric current that LED light is passed through in accelerated life test.LED lamp is lighted with constant acceleration electric current at a temperature of acceleration
Sample is the pulse electricity of Calibrated current to LED light sample load size using the pulse power after lamps and lanterns reach thermal steady state
Stream, the voltage value measured at this time are regarded as the corresponding junction voltage value of the sample to work under room temperature environment, record the voltage value.
It can calculate the sample lamps and lanterns according to junction temperature and section voltage relationship calibration curve L0 (temperature is answered in the acceleration temperature
Power) and accelerate electric current (electric stress) under the conditions of junction temperature value.
In step s 4, using the pulse current of Calibrated current, the beneficial effect is that pulse current is not produced from LED light
Heat effect.
Test method of the invention only need to once demarcate and can measure LED light under the conditions of different temperatures and electric stress
Junction temperature effectively improves testing efficiency.
Test method of the invention is further illustrated below by way of specific embodiment.
It chooses with the double stress accelerated life tests of 4 groups of carry out electric-thermals of a batch of LED lamp sample point.Temperature is accelerated to answer
The acceleration temperature that the combination of power and electric stress organizes 1 as shown in table 1 is 70 DEG C, and acceleration electric current is 53mA；The acceleration temperature 80 of group 2
DEG C, accelerate electric current 53mA；The acceleration temperature 60 C of group 3, acceleration electric current are 62mA；The acceleration temperature 70 C of group 4, acceleration electric current are
62mA。
LED lamp sample is lighted with the constant current of 1mA first, is fixed in 30 DEG C of insulating box 30 minutes, makes LED
Lamp is substantially stabilized and reaches hot stable state.Due to electric current very little, electric current can ignore that the self-heating effect of LED light, can recognize
Junction temperature for sample at this time is consistent with environment temperature, and collected sample voltage value is that the sample is corresponding at 30 DEG C of junction temperature
Junction voltage value.It at interval of 20 DEG C of change environment temperatures within the scope of 30 DEG C to 130 DEG C, and repeats the above steps, to obtain sample
Product corresponding junction voltage value under different junction temperatures.Using the value of corresponding junction voltage under different junction temperatures, carried out according to above-mentioned formula
Linear fit, Fig. 2 be the junction temperature of sample from the linear fit of junction voltage as a result, wherein being measured under the different junction temperatures of discrete point
Voltage value, solid line are the curve after linear fit.
Have sample with constant acceleration electric current (53mA) lightening LED lamp under 70 DEG C of environment, after lamps and lanterns reach thermal balance,
Using the pulse power to the pulse current of sample load size 1mA, the voltage value measured at this time is 34.5613V, it is believed that is being added
Fast temperature is 70 DEG C, accelerates electric current under the conditions of 53mA, the junction temperature of sample is 119.8 DEG C.For different temperature stress and electricity
The combination of stress can repeat the above steps.Lightening LED lamp has sample under the stress combination condition, reaches stable to lamps and lanterns
State loads 1mA pulse current to sample, surveys the voltage value at its both ends, and table 2 is the junction temperature of other group of sample.
Table 1
| Environment temperature (DEG C) | Operating current (mA) | Junction temperature (DEG C) |
| 70 | 53 | 119.8 |
| 80 | 53 | 128.4 |
| 60 | 62 | 120.2 |
| 70 | 62 | 130.5 |
Table 2
The above described specific embodiments of the present invention are not intended to limit the scope of the present invention..Any basis
Any other various changes and modifications made by technical concept of the invention should be included in the guarantor of the claims in the present invention
It protects in range.
Claims (9)
1. a kind of method for testing junction temperature of LED light, which comprises the following steps:
S1 makes LED light reach thermal steady state, institute under scheduled environment temperature using constant Calibrated current lightening LED lamp
The junction temperature that environment temperature when LED light reaches thermal steady state under the conditions of Calibrated current is LED light is stated, LED light both ends are acquired
Voltage value；
S2 changes environment temperature, and LED light is made to reach thermal steady state under conditions of varying environment temperature, acquires LED light both ends
Corresponding voltage value at different ambient temperatures；
S3, according to the voltage at the LED light both ends measured at a temperature of the varying environment temperature and varying environment in step S1 and S2
Value carries out linear fit, obtains the relationship calibration curve of the LED light junction temperature and voltage；
S4 uses constant acceleration electric current lightening LED lamp under conditions of accelerating temperature, after LED light reaches thermal steady state,
By constant acceleration current switching at the pulse current of Calibrated current, the voltage value at LED light both ends is measured, and according in step S3
LED light is calculated in the case where accelerating temperature and accelerating current condition in the relationship calibration curve of the LED light junction temperature and voltage that measure
Junction temperature.
2. the method for testing junction temperature of LED light according to claim 1, which is characterized in that the value model of the Calibrated current
It encloses for 5% less than LED light rated current.
3. the method for testing junction temperature of LED light according to claim 2, which is characterized in that the value of the Calibrated current is
1mA。
4. the method for testing junction temperature of LED light according to claim 1, which is characterized in that in step s 4, the calibration electricity
The pulse width of stream is less than 10ms and is greater than 0.
5. the method for testing junction temperature of LED light according to claim 1, which is characterized in that in the step S3, according to step
The voltage value at the LED light both ends measured at a temperature of the varying environment temperature and varying environment in S1 and S2 simultaneously combines formula VF
=-A1×t+B1Linear fit is carried out, wherein A1、B1For constant, VFFor the forward voltage at LED light both ends, t is the junction temperature of LED light.
6. the method for testing junction temperature of LED light according to claim 1, which is characterized in that place LED light in test process
In insulating box, the environment temperature is the temperature in insulating box.
7. the method for testing junction temperature of LED light according to claim 6, which is characterized in that by changing the temperature in insulating box
Degree, makes LED light reach thermal steady state under conditions of varying environment temperature.
8. the method for testing junction temperature of LED light according to claim 1, which is characterized in that the difference of the varying environment temperature
Value is 20 DEG C.
9. the method for testing junction temperature of LED light according to claim 1, which is characterized in that make LED light every in test process
It is kept at least 30 minutes under a kind of environment temperature.
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| CN201811423223.3A CN109596962A (en) | 2018-11-27 | 2018-11-27 | The method for testing junction temperature of LED light |
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ID=65959695
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114047224A (en) * | 2021-11-24 | 2022-02-15 | 江苏省特种设备安全监督检验研究院 | Method for testing junction temperature and temperature distribution of gallium nitride-based blue light LED |
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| CN102072783A (en) * | 2010-11-18 | 2011-05-25 | 上海第二工业大学 | Method for testing junction temperature of LED |
| CN103162856A (en) * | 2011-12-19 | 2013-06-19 | 上海航空电器有限公司 | Non-contact high-power light-emitting diode (LED) junction temperature test method |
| CN106323496A (en) * | 2016-09-19 | 2017-01-11 | 福州大学 | Novel LED junction temperature measuring method |
| CN106990368A (en) * | 2017-05-19 | 2017-07-28 | 中国科学院长春光学精密机械与物理研究所 | A kind of junction temperature measurement method of LED lamp |
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2018
- 2018-11-27 CN CN201811423223.3A patent/CN109596962A/en active Pending
Patent Citations (5)
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| 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 |
| CN102072783A (en) * | 2010-11-18 | 2011-05-25 | 上海第二工业大学 | Method for testing junction temperature of LED |
| CN103162856A (en) * | 2011-12-19 | 2013-06-19 | 上海航空电器有限公司 | Non-contact high-power light-emitting diode (LED) junction temperature test method |
| CN106323496A (en) * | 2016-09-19 | 2017-01-11 | 福州大学 | Novel LED junction temperature measuring method |
| CN106990368A (en) * | 2017-05-19 | 2017-07-28 | 中国科学院长春光学精密机械与物理研究所 | A kind of junction temperature measurement method of LED lamp |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114047224A (en) * | 2021-11-24 | 2022-02-15 | 江苏省特种设备安全监督检验研究院 | Method for testing junction temperature and temperature distribution of gallium nitride-based blue light LED |
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Application publication date: 20190409 |