CN102183546A - Detection device and method for package interface of light emitting diode - Google Patents
Detection device and method for package interface of light emitting diode Download PDFInfo
- Publication number
- CN102183546A CN102183546A CN2011100077300A CN201110007730A CN102183546A CN 102183546 A CN102183546 A CN 102183546A CN 2011100077300 A CN2011100077300 A CN 2011100077300A CN 201110007730 A CN201110007730 A CN 201110007730A CN 102183546 A CN102183546 A CN 102183546A
- Authority
- CN
- China
- Prior art keywords
- led element
- electric current
- test
- time
- led
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Abstract
The invention relates to a detection device and a method for the package interface of a light emitting diode. The detection device for the package interface of the light emitting diode (LED) used for the detection of LEDs comprises a current source, a voltage detection device and a test control unit. The current source is commanded to output at least one current to the LED element by at least one control signal provided by the test control unit. At least two signals are provided so as to respectively command the voltage detection device to measure the first forward voltage of the LED element at a first time and the second forward voltage thereof at a second time. The voltage difference valve between the first forward voltage and the second forward voltage is calculated by the test control unit. When the voltage difference valve is greater than a preset failure judgment value, the LED element is determined to be invalid.
Description
Technical field
The present invention relates to the pick-up unit and the method for a kind of light emitting diode (LED) package interface.
Background technology
The LED encapsulation procedure comprises solid crystalline substance, routing, sealing and detection, and wherein solid brilliant processing procedure is to use solid brilliant material (as elargol, eutectic alloy or heat-conducting glue etc.) that led chip is pasted and fixed on package carrier or the substrate.If, will cause solid brilliant interface quality that fine or not uneven problem is arranged Gu consolidate phenomenons such as brilliant material generation is in uneven thickness, hole, deterioration in characteristics in the brilliant process.On the LED component package is finished quick photoelectric characteristic machines dispatching from the factory before, there is no at present and carry out the good and bad detection step of screening of solid brilliant quality.Gu the bad meeting of brilliant quality makes LED element thermal resistance value higher, heat conduction is bad, when subsequent clients is used, will cause LED overheated, ahead of time problems such as light decay or damage.
The method of assessment LED element thermal conduction characteristic for example adopts the thermal resistance measurement board to carry out thermal resistance measurement according to standard JEDEC-51, MIL-STD-883, CNS15248 at present, but consuming time again because of thermal resistance measurement step complexity, the instant QC test item before can't dispatching from the factory as the LED element.
Summary of the invention
The present invention proposes a kind of package interface detection method of LED fast and device, needn't measure the thermal resistance value of LED element, each LED element only needs can tell less than several seconds time the difference of package interface between each LED element (for example solid brilliant) quality consuming timely.This detection method and device are used in combination with the general quick photoelectric characteristic machines of LED, can before the LED element dispatches from the factory, carry out the screening of solid brilliant defective products fast.
The pick-up unit of the light emitting diode of one embodiment of the invention (LED) package interface detects for the LED element with a package interface.The pick-up unit of LED package interface comprises current source, voltage check device and unit of testing and controlling.Unit of testing and controlling provides at least one this current source of control signal order to export at least one electric current to this LED element, and provide binary signal at least, order one first forward voltage (forward voltage) of this voltage check device respectively in very first time measurement LED element, and in one second forward voltage of one second time measurement LED element.Wherein this unit of testing and controlling calculate this first and the voltage difference of this second forward voltage, and judge that then this LED element is judged to be inefficacy when this voltage difference is preset the inefficacy decision content greater than one.
The detection method of the LED package interface of one embodiment of the invention detects for the LED element with a package interface, and it comprises following steps: provide at least one electric current to this LED element; Utilize this at least one electric current to measure one first forward voltage of this LED element in a very first time, and in one second forward voltage of one second this LED element of time measurement; Calculate this first and a voltage difference of this second forward voltage; And judge that then this LED element is judged to be inefficacy when this voltage difference is preset the inefficacy decision content greater than one.
The detection method of the LED package interface of another embodiment of the present invention detects for a plurality of LED elements with package interface, and it comprises following steps: at least one electric current is provided; Utilize this at least one electric current to measure one first forward voltage of each LED element in a very first time, and in one second forward voltage of one second each LED element of time measurement; Calculate each LED element this first and a voltage difference of this second forward voltage; And according to these a plurality of LED elements of this voltage difference classification of each LED element.The very first time of wherein measuring each LED element is all identical, and it is all identical to measure second time of each LED element.Adopt the same detection condition by this, to carry out the classification of a plurality of LED elements.
Another embodiment of the present invention comprises a kind of computer program that is used to detect the package interface of a LED element, it comprises one and contains the computer read/write memory medium that a computer-readable medium instructs, and this computer-readable medium instruction comprises to give an order: one first instruction provides at least one electric current to this LED element; One second instruction utilizes this at least one electric current to measure one first forward voltage of this LED element and in one second forward voltage of one second this LED element of time measurement in a very first time; One the 3rd command calculations this first and a voltage difference of this second forward voltage; And one the 4th instruction judge that then this LED element is judged to be inefficacy when this voltage difference is preset the inefficacy decision content greater than one.
Description of drawings
Fig. 1 shows the package interface synoptic diagram of the LED element that is assembled in circuit board.
Fig. 2 shows that two forward voltage differences of LED element are with feeding the graph of a relation that current time increases.
Fig. 3 shows the block schematic diagram of the LED package interface pick-up unit of one embodiment of the invention.
Fig. 4 is the flow chart of steps of the detection method of LED package interface of the present invention.
Fig. 5 is the corresponding relation figure of the test of first embodiment of the invention with electric current and forward voltage and time.
Fig. 6 is the corresponding relation figure of the test of second embodiment of the invention with electric current and forward voltage and time.
Fig. 7 shows that the forward voltage difference of LED element is with feeding the experiment measuring figure that current time increases.
Fig. 8 is the test of third embodiment of the invention electric current and the corresponding relation figure of heating with electric current and forward voltage and time.
Fig. 9 is the test of fourth embodiment of the invention electric current and the corresponding relation figure of heating with electric current and forward voltage and time.
Figure 10 is the corresponding relation figure of the test of fifth embodiment of the invention with electric current and forward voltage and time.
Figure 11 is the corresponding relation figure of the test of sixth embodiment of the invention with electric current and forward voltage and time.
Figure 12 is the test of seventh embodiment of the invention electric current and the corresponding relation figure of heating with electric current and forward voltage and time.
Figure 13 is the test of eighth embodiment of the invention electric current and the corresponding relation figure of heating with electric current and forward voltage and time.
Figure 14 is the test of ninth embodiment of the invention electric current and the corresponding relation figure of heating with electric current and forward voltage and time.
Figure 15 is the test of tenth embodiment of the invention electric current and the corresponding relation figure of heating with electric current and forward voltage and time.
Figure 16 is the flow chart of steps of the detection method of another embodiment of the present invention LED package interface.
[main element symbol description]
10 LED elements, 11 chips
12 package carriers, 13 solid brilliant interfaces
14 assembling interfaces, 15 circuit boards
16 package interfaces
The pick-up unit of 20 LED package interfaces
22 current sources, 23 voltage check devices
24 unit of testing and controlling, 25 LED elements
Second time of t1 very first time t2
Th heating td interval time interval time
The V1 first forward voltage V2 second forward voltage
S1, S1 ', S1 ", S1 " ' control signal S2, S3 signal
Embodiment
For fully understanding feature of the present invention and effect, now by following concrete enforcement example, and cooperate appended graphicly, the present invention is described in detail, illustrate as afterwards:
When the solid brilliant quality of LED is bad, feed under the same nominal electric current, solid brilliant bad LED element its connect surface temperature can be than consolidating the normal LED element of brilliant quality height.The present invention promptly proposes the instant LED of detection package interface method by above-mentioned characteristic, to improve tradition to measure the solid brilliant quality complexity problem consuming time again of LED thermal resistance value screening LED.
Fig. 1 shows that one is assembled in the package interface synoptic diagram of the LED element 10 of circuit board, and wherein led chip 11 is solid brilliant on package carrier 12, and 12 of its chips 11 and package carriers form solid brilliant interface 13.Gu brilliant interface 13 can comprise as elargol, eutectic alloy or heat-conducting glue etc.LED element 10 comprises chip 11, solid brilliant interface 13 and package carrier 12.Package carrier 12 is assembled on the circuit board 15, forms assembling interface 14 therebetween.By this, in fact relevant with the heat radiation of led chip 11 package interface 16 comprises solid brilliant interface 13 and assembling interface 14.
Measuring principle of the present invention is to utilize the forward voltage values of LED to connect the characteristic that the rising of surface temperature reduces with LED.When LED is passed into this at least one electric current, the PN of LED meets the face place and also can generate heat except luminous, LED connects surface temperature just to begin to rise, the forward voltage values of LED just begins to reduce the voltage difference dv (negative value) that causes the second forward voltage V2 to deduct the first forward voltage V1 rapidly and continues to increase, as shown in Figure 2.Feed under the electric current that equates at identical led chip, the speed that the LED forward voltage values descends is relevant with the ability of the outside conduction of institute's thermal value.When the outside conduction of the heat that LED produced was subjected to hindering, the speed that the LED forward voltage values descends can be accelerated.That is in identical conduction time, the forward voltage difference of the heat conduction of measuring LED energising moment and LED to the package interface, outwards the relatively poor LED of thermal conduction capability will present bigger voltage difference.
It is bad in LED component package processing procedure that solid brilliant interface can screening be come out by the measurement of above-mentioned forward voltage difference.Even when the LED element was assembled into circuit board or thermal conductive metal plate, the formed high thermal resistance interface of bad assembling interface also can utilize the measurement of above-mentioned forward voltage difference to carry out screening.
For understanding the detection method of LED package interface of the present invention, the pick-up unit of LED package interface of the present invention is described below.With reference to Fig. 3, LED package interface pick-up unit 20 of the present invention comprises current source 22, voltage check device 23 and unit of testing and controlling 24.Among one embodiment, this LED element 25 is equivalent to LED element 10 shown in Figure 1.
Fig. 4 shows the flow chart of steps of the detection method of LED package interface of the present invention, and detection method of the present invention comprises step S10 provides at least one electric current to this LED element; Step S12 utilizes this at least one electric current to measure one first forward voltage of this LED element in a very first time, and in one second forward voltage of one second this LED element of time measurement; Step S14 calculates the voltage difference of this first and second forward voltage; And step S16 judges that then this LED element is judged to be inefficacy when this voltage difference is preset the inefficacy decision content greater than one.
Among each following embodiment, please be jointly with reference to Fig. 3 and Fig. 4 in order to pick-up unit and the detection method of understanding LED package interface of the present invention.
In the first embodiment of the invention as shown in Figure 5, unit of testing and controlling 24 provide at least one control signal S1 command current source 22 at least one test of output with at least one electric current to this LED element 25, and provide at least twice signal S2, S3 command voltage pick-up unit 23 is measured the forward voltage of these LED elements 25, so obtain the first forward voltage V1 respectively at the very first time; Obtain the second forward voltage V2 in second time.In other words, current source 22 requires to provide at least one test electricity consumption to flow to this LED element according to the control signal S1 of unit of testing and controlling 24, and voltage check device 23 is according to the signal S2 of unit of testing and controlling 24, and S3 requires to measure these two forward voltages of this LED element 25.Must notice that the framework of device of the present invention is not limited to the above embodiment framework that discloses, and can be required and change according to practical application.
Unit of testing and controlling 24 reads these two the forward voltage V1 with measured this LED element 25 of recording voltage pick-up unit 23, and V2 calculates both voltage difference.Afterwards, unit of testing and controlling 24 is judged to be inefficacy according to a predefined voltage difference inefficacy decision content when voltage difference of test LED element 25 is preset the inefficacy decision content greater than one.
In addition, a plurality of LED elements are taked same test condition (first and second identical time), can differentiate the LED element and be inefficacy (defective products) or effective (non-defective unit), and classify.That is in other embodiments, unit of testing and controlling 24 reads two forward voltage V1 with the measured a plurality of LED elements 25 of recording voltage pick-up unit 23, and V2 calculates both voltage difference.Afterwards, unit of testing and controlling 24 is classified to a plurality of LED elements 25 of test according to predefined voltage difference sorted table and measured voltage difference, promptly is divided into non-defective unit and defective products.
Please in the lump with reference to figure 3 and Fig. 4, Fig. 6 is the corresponding relation figure of the test of second embodiment of the invention with at least one electric current and forward voltage and time.Unit of testing and controlling 24 provides at least one test electricity consumption of 22 outputs of at least one control signal S1 command current source to flow to this LED element 25, and provide at least twice signal S2, S3 command voltage pick-up unit 23 is measured a plurality of forward voltages of this LED element 25 in regular turn, be contained in the first forward voltage V1 that very first time t1 obtains to obtain a plurality of forward voltages, the second forward voltage V2 that obtains at the second time t2.In other words, current source 22 requires to provide at least one test electricity consumption to flow to this LED element according to the control signal S1 of unit of testing and controlling 24, and voltage check device 23 is according to the signal S2 of unit of testing and controlling 24, and S3 requires to measure a plurality of forward voltages of this LED element 25.
In addition, unit of testing and controlling 24 reads a plurality of forward voltages with measured this LED element 25 of recording voltage pick-up unit 23, and reads in predefined time t1 and two measured forward voltage V1 of t2, and V2 calculates both voltage difference.Wherein a plurality of forward voltages are along with time remaining descends, so the V1 forward voltage values is greater than the V2 forward voltage values.Afterwards, unit of testing and controlling 24 is according to a predefined voltage difference inefficacy decision content, the voltage difference of this LED element 25 of test is judged to be inefficacy during greater than the inefficacy decision content.
A predefined voltage difference inefficacy decision content is to decide according to the chip of LED element and the interval td of encapsulating structure and two Measuring Time.To measure bigger voltage difference if the encapsulating structure heat conduction of LED element is relatively poor.Similarly, for the LED element with identical chips structure and encapsulating structure, the interval td of two Measuring Time is long more, and voltage difference also can be healed greatly.Fig. 7 shows that the forward voltage difference of 20 LED elements is with feeding the experiment measuring figure that current time increases.Narrate according to second embodiment, at least one electric current 350 milliampere to LED elements are provided, voltage check device is measured a plurality of forward voltages of LED element in regular turn.After at least one electric current was exported 20 microseconds, the first forward voltage V1 was measured to, and whole voltage differences subtracts the first forward voltage V1 by other forward voltages (being later than the first forward voltage V1) and obtains as shown in Figure 7 curve.Predefined time t1 is that electric current is exported 20 microseconds in this experiment, when predefined time t2 be electric current output in the time of 0.1 second the second forward voltage V2 be measured to, preestablish voltage difference inefficacy decision content and then be set at 200 millivolts this moment, if the voltage difference of LED element is when preestablishing voltage difference inefficacy decision content, the LED element then is judged as inefficacy.Moreover, if when predefined time t2 be electric current output in the time of 5 seconds the second forward voltage V2 be measured to, preestablish voltage difference inefficacy decision content and then be set at 250 millivolts this moment.Therefore, using the present invention before detection of LED package interface and defective products screening, but reference example two and this description of test are set the voltage difference inefficacy decision content that is fit to.
In first and second embodiment, the test of being exported by current source 22 can be pulse current or DC current with electric current, and test can be according to the structure setting of LED element 25 with current value, and the rated current that adopts LED element 25 usually is as the test electric current.The load current value of LED element 25 with led chip area of 1 square millimeter can be between 250 milliampere to 350 milliamperes.In addition, can be between 10 milliampere to 20 milliamperes if having the load current value of LED element 25 of 0.1 square millimeter led chip area.Moreover interval td determines with the structure or the pattern of electric current and LED element 25 according to test between the voltage measurement, and generally speaking interval time, td was between between 100 microseconds to 1 second.Yet the present invention is not limited to the every data among first embodiment and second embodiment.
In the third embodiment of the present invention as shown in Figure 8, unit of testing and controlling 24 provides 22 outputs, the one test electricity consumption of one first control signal S1 command current source to flow to this LED element 25, and provides signal S2 command voltage pick-up unit 23 to measure the forward voltage V1 of this LED element 25.Then unit of testing and controlling 24 provides 22 outputs, the one heating electricity consumption of one second control signal S1 ' command current source to flow to this LED element 25.After heating th interval time, unit of testing and controlling 24 provides one the 3rd control signal S1, and " command current source 22 stops to heat with electric current and begins output test electric current.Unit of testing and controlling 24 provides a signal S3 command voltage pick-up unit 23 to measure the forward voltage V2 of this LED element 25 in the second time t2 simultaneously.
Then, this unit of testing and controlling 24 reads these two the voltage V1 with measured this LED element 25 of recording voltage pick-up unit 23, V2, and calculate both voltage difference.Afterwards, unit of testing and controlling 24 is according to a predefined voltage difference inefficacy decision content, the voltage difference of this LED element 25 of test is judged to be inefficacy during greater than the inefficacy decision content.
In the 3rd embodiment, the test of being exported by current source 22 can be the pulse current of pulse width 20 microsecond to 100 microseconds with electric current, and tests with current value and set according to the structure of LED element 25.The test of Cai Yonging can be between 0.1 milliampere to 5 milliampere with current value in this embodiment.The heating of being exported by current source 22 can be pulse current or DC current with electric current, and heating is set according to the structure of LED element 25 with current value.Usually adopt the load current value of LED element 25 as the heating electric current.Heating th interval time determines with the structure or the pattern of current value and LED element 25 according to test, generally speaking heats interval time th between between 100 microseconds to 1 second.Compared to first embodiment, the test among the 3rd embodiment is less with current value, therefore can avoid the measuring error that additional heat caused that is produced by big electric current.
In the same manner, comprise voltage V1 and V2 in order to obtain a plurality of forward voltages in different time among the 4th embodiment, as shown in Figure 9, current source 22 alternatively provides test to flow to LED element 25 with electric current and heating electricity consumption.Unit of testing and controlling 24 provides at least two signal S2, and S3 command voltage pick-up unit 23 is measured a plurality of forward voltages of this LED element 25 in order with electric current with this test.
Unit of testing and controlling 24 reads with a plurality of forward voltages of the measured LED element 25 of recording voltage pick-up unit 23 and reads in predefined time t1 and two measured forward voltage V1 of t2, V2, and calculate both voltage difference.Wherein these forward voltages are along with time remaining descends, and forward voltage values V1 is greater than forward voltage values V2.Then unit of testing and controlling 24 is according to a predefined voltage difference inefficacy decision content, the voltage difference of test LED element 25 is judged to be inefficacy during greater than the inefficacy decision content.
In the fifth embodiment of the present invention as shown in figure 10, unit of testing and controlling 24 provides 22 outputs, the one first test electricity consumption of one first control signal S1 command current source to flow to this LED element 25, and provides signal S2 command voltage pick-up unit 23 to measure the forward voltage V1 of this LED element 25.Then unit of testing and controlling 24 provides 22 outputs, the one second test electricity consumption of second control signal S1 ' command current source to flow to this LED element 25, and provides a signal S3 command voltage pick-up unit 23 to measure the forward voltage V2 of this LED element 25.In this embodiment, first test can be pulse current with the electric current and second test with electric current, and first test equates with the load current value of this LED element 25 with current value with the current value and second test.As shown in figure 10, the pulse width that electric current is used in first test is between 20 microsecond to 100 microseconds, and second test is bigger with the pulse width of electric current than first test with the pulse width of electric current.Second test between between 100 microseconds to 1 second, can cause the surface temperature that connects of this LED element 25 to rise with the pulse width of electric current, and forward voltage descends.
Unit of testing and controlling 24 reads the forward voltage (V1 and V2) with the measured LED element 25 of recording voltage pick-up unit 23, and calculates both voltage differences.Then unit of testing and controlling 24 is according to a predefined voltage difference inefficacy decision content, the voltage difference of test LED element 25 is judged to be inefficacy during greater than the inefficacy decision content.
In the same manner, among the 6th embodiment in order to obtain a plurality of forward voltages in different time, as shown in figure 11, unit of testing and controlling 24 provides a plurality of control signal command currents source 22 output to have broaden the gradually pulsed test electricity consumption of characteristic of pulse width to flow to LED element 25 and provide a plurality of signal command voltage check devices 23 to measure a plurality of forward voltages of this LED element 25 in order.The surface temperature that connects of this LED element 25 will be owing to the increase of pulse width rises in time, that is the forward voltage of this LED element 25 descends in time.
Unit of testing and controlling 24 reads with a plurality of forward voltages of the measured LED element 25 of recording voltage pick-up unit 23 and reads in predefined time t1 and two measured forward voltage V1 of t2, V2, and calculate both voltage difference.Wherein these forward voltages are along with time remaining descends, and forward voltage values V1 is greater than forward voltage values V2.Then unit of testing and controlling 24 is according to a predefined voltage difference inefficacy decision content, the voltage difference of test LED element 25 is judged to be inefficacy during greater than the inefficacy decision content.
In addition, the LED following general who has surrendered that connects surface temperature causes the rising of LED forward voltage.The heating of this LED element input a period of time with after the electric current, is stopped heating and uses electric current, use the LED element is measured at least one test in order with electric current (pulse current that for example has short pulse width) a plurality of forward voltages instead.In the case, the forward voltage fast rise of LED element so that forward voltage difference dv (on the occasion of) can increase in time.Particularly, this LED element with bad package interface will demonstrate bigger forward voltage difference than the LED element that well packaged interface quality is arranged.
In the seventh embodiment of the present invention as shown in figure 12, unit of testing and controlling 24 provides 22 outputs, the one heating electricity consumption of one first control signal S1 command current source to flow to this LED element 25.After heating current output one heating th interval time, unit of testing and controlling 24 provides a signal S2 command voltage pick-up unit 23 to measure the forward voltage V1 of this LED element 25, and provides one second control signal S1 ' command current source 22 to stop output heating electric current.Then unit of testing and controlling 24 provides the 3rd control signal S1, and " command current source 22 is exported a test electricity consumption with short pulse width an interval time behind the td and is flow to this LED element 25, and provides a signal S3 command voltage pick-up unit 23 to measure the forward voltage V2 of these LED elements 25.As shown in figure 12, test equates with the load current value of LED element 25 with current value with current value and heating.Test uses the pulse width of electric current between 20 microsecond to 100 microseconds.
Unit of testing and controlling 24 reads the forward voltage (as V1 and V2) with the measured LED element 25 of recording voltage pick-up unit 23, and calculates both voltage differences.Then unit of testing and controlling 24 is according to a predefined voltage difference inefficacy decision content, the voltage difference of test LED element 25 is judged to be inefficacy during greater than the inefficacy decision content.Because LED element 25 is measured in heating th heating interval time and by the test electricity consumption stream with short pulse width with electric current by heating, LED element 25 connect surface temperature will be after heating th interval time decline and its voltage difference that measures will on the occasion of.
In the same manner, among the 8th embodiment in order to obtain a plurality of forward voltages in different time, as shown in figure 13, after heating stopped with electric current, the test electricity consumption that unit of testing and controlling 24 provides a plurality of control signal command currents source 22 to export short pulse width in order flow to LED element 25 and provides a plurality of signal command voltage check devices 23 to measure the forward voltage of LED element 25 in order.Current source 22 output heating electricity consumption during heating th interval time flow to LED element 25.The surface temperature that connects of LED element 25 begins after the th to descend in heating interval time, and forward voltage begins to rise.As shown in figure 13, test uses the pulse width of electric current between 20 microsecond to 100 microseconds.Test equates with the load current value of LED element 25 with current value with current value and heating.
Unit of testing and controlling 24 reads with a plurality of forward voltages of the measured LED element 25 of recording voltage pick-up unit 23 and reads in predefined time t1 and two measured forward voltage V1 of t2, V2, and calculate both voltage difference.Wherein these forward voltages are along with time remaining rises, and forward voltage values V1 is less than forward voltage values V2.Then unit of testing and controlling 24 is according to a predefined voltage difference inefficacy decision content, the voltage difference of test LED element 25 is judged to be inefficacy during greater than the inefficacy decision content.
In the ninth embodiment of the present invention as shown in figure 14, unit of testing and controlling 24 provides 22 outputs, the one heating electricity consumption of one first control signal S1 command current source to flow to this LED element 25.After heating th interval time, unit of testing and controlling 24 provides one second control signal S1 ' command current source 22 to stop the output heating and uses electric current, and the 3rd control signal S1 is provided, and " the 22 output test electricity consumptions of command current source flow to this LED element 25.Then unit of testing and controlling 24 provides signal S2 command voltage pick-up unit 23 to measure the forward voltage V1 of this LED element 25.Unit of testing and controlling 24 provides the 4th control signal S1, and " ' command current source 22 is exported test interval time after the td and is used electric current, and provides signal S3 command voltage pick-up unit 23 to measure the forward voltage V2 of these LED elements 25.
Unit of testing and controlling 24 reads two forward voltages (as V1 and V2) with the measured LED element 25 of recording voltage pick-up unit 23, and calculates both voltage differences.Then unit of testing and controlling 24 is according to a predefined voltage difference inefficacy decision content, the voltage difference of test LED element 25 is judged to be inefficacy during greater than the inefficacy decision content.Because LED element 25 by heating with electric current in heating th heating interval time and measure by test electricity consumption stream with short pulse width, LED element 25 connect surface temperature will be after heating th interval time decline and its voltage difference that measures will on the occasion of.In this embodiment, heating equates with the load current value of LED element 25 with current value.Test uses current value between 0.1 milliampere to 5 milliampere, to reduce the issuable thermal effect of big electric current.Test uses the pulse width of electric current between 20 microsecond to 100 microseconds.Yet the present invention is not limited to the described condition of this embodiment.
In the same manner, among the tenth embodiment in order to obtain a plurality of forward voltages in different time, as shown in figure 15, when heating had stopped output with electric current after, unit of testing and controlling 24 provided a plurality of control signal command currents source 22 to export current in short bursts in order to LED element 25 and provide a plurality of signal command voltage check devices 23 to measure a plurality of forward voltages of this LED element 25 in order.Current source 22 output heating electricity consumption in heating th interval time flow to this LED element 25.After heating th interval time, the surface temperature that connects of this LED element 25 descends, and forward voltage begins to rise.
Unit of testing and controlling 24 reads with a plurality of forward voltages of recording voltage pick-up unit 23 measured LED element 25 after heating interval time th and reads in predefined time t1 and two measured forward voltage V1 of t2, V2, and calculate both voltage difference.Wherein these forward voltages are along with time remaining rises, and forward voltage values V1 is less than forward voltage values V2.Then unit of testing and controlling 24 is according to a predefined voltage difference inefficacy decision content, the voltage difference of test LED element 25 is judged to be inefficacy during greater than the inefficacy decision content.
In aforementioned each embodiment, when providing the 22 output test electricity consumptions of control signal command current source, unit of testing and controlling 24 flow to this LED element 25, and when providing signal command voltage check device 23 to measure the forward voltage of LED element 25, can before voltage measurement, set a time delay to reduce voltage measurement error.Time delay is between 5 microsecond to 50 microseconds.Interval td and heating th interval time determine according to the structure or the pattern of test with current value and LED element 25 between the voltage measurement.Generally speaking, interval time, td and heating th interval time were between 100 microseconds and between 1 second.Yet the present invention is not as limit.Pick-up unit 20 employed voltage check devices 23 of the present invention are a quick and high-res voltage check device, and its voltage resolution should be less than 5mV, and the best is less than 0.2mV, but the present invention is not as limit; The sampling rate per second should be higher than 200,000 times, and the best can be sampled 1,000,000 times for per second, but the present invention is not as limit.
The present invention further provides the computer program of a detection LED element, it comprises one and contains the computer read/write memory medium that a computer-readable medium instructs, and this computer-readable medium instruction comprises to give an order: first instruction provides at least one electric current to this LED element; Second instruction utilizes this electric current to measure one first forward voltage of this LED element and in one second forward voltage of one second this LED element of time measurement in a very first time; The 3rd command calculations this first and a voltage difference of this second forward voltage; And the 4th instruction judge that then this LED element is judged to be inefficacy when this voltage difference is preset the inefficacy decision content greater than one.
When the package interface of a plurality of LED elements detected, unit of testing and controlling 24 can be carried out the height classification of LED element 25 according to the voltage difference of a plurality of LED.Figure 16 shows the flow chart of steps of the detection method of another embodiment of the present invention LED package interface.The detection method of this LED package interface comprises step S20 provides at least one electric current; Step S22 utilizes this electric current to measure first forward voltage of these a plurality of LED elements in a very first time, and in second forward voltage of one second these a plurality of LED elements of time measurement; Step S24 calculates the voltage difference of this first and second forward voltage; And step S26 classifies to a plurality of LED elements according to these a plurality of voltage differences.This very first time of wherein measuring each this LED element equates, and this second time of measuring each this LED element equates.
The present invention proposes a kind of package interface detection method of LED fast and device.LED is fed pulse current or the DC current of a bit of time, measure one first forward voltage of this LED element simultaneously in a very first time, and in one second forward voltage of one second this LED element of time measurement, calculating the voltage difference of first forward voltage and second forward voltage, is the quality of the solid brilliant quality of distinguishable LED by the difference that compares each LEDs forward voltage difference.Because of required time of detection of the present invention only needs several microseconds, thus be used in combination with the general quick photoelectric characteristic machines of LED, can be in the screening of brilliant defective products of tachy steroling soon on the line of advancing of dispatching from the factory of LED element.
Below the present invention is described in detail, yet the above only is a preferred enforcement example of the present invention, when not limiting scope of the invention process.Be that all equalizations of doing according to the claimed scope of claims of the present invention change and modify etc., all should still belong in the claimed scope of claims of the present invention.
Claims (35)
1. the pick-up unit of a LED package interface detects for the LED element with a package interface, comprises:
One current source;
One voltage check device; And
One unit of testing and controlling, provide at least one this current source of control signal order to export at least one electric current to this LED element, and provide binary signal at least, order this voltage check device to measure one first forward voltage of this LED element respectively in a very first time, and in one second forward voltage of one second this LED element of time measurement;
Wherein this unit of testing and controlling calculate this first and the voltage difference of this second forward voltage, and judge that then this LED element is judged to be inefficacy when this voltage difference is preset the inefficacy decision content greater than one.
2. the pick-up unit of LED package interface as claimed in claim 1, wherein this electric current is a test electric current, this current source provides this test electricity consumption to flow to a plurality of forward voltages that this LED element and this voltage check device are measured this LED element in order in regular turn, comprising this first forward voltage of measuring this LED element in this very first time, at this second forward voltage of this this LED element of second time measurement.
3. the pick-up unit of LED package interface as claimed in claim 2, wherein to export this test current value of this LED element be a rated current of this LED element to this current source.
4. the pick-up unit of LED package interface as claimed in claim 1, wherein should the very first time and interval time of this second time between 100 microseconds (μ sec) to 1 second (sec).
5. the pick-up unit of LED package interface as claimed in claim 1, wherein this at least one electric current comprises a test and uses electric current with an electric current and a heating, this the test with current value between 0.1 milliampere (mA) between 5 milliamperes, this heating equates with a load current value of this LED element with current value, this current source is exported this test electricity consumption respectively at this very first time and this second time and is flow to this LED element, before this second time one the heating interval time, this current source is exported this heating electricity consumption and is flow to this LED element, and this heating interval time is between between 100 microseconds to 1 second.
6. the pick-up unit of LED package interface as claimed in claim 1, wherein this current source is alternatively exported a test and is flow to this LED element with an electric current and a heating electricity consumption, this voltage check device is measured a plurality of forward voltages of this LED element in order with electric current with this test, comprising in this very first time, when this test exports this LED element to electric current, measure this first forward voltage, in this second time, when this test exports this LED element to electric current, measure this second forward voltage.
7. the pick-up unit of LED package interface as claimed in claim 1, wherein this at least one electric current comprises one first test and uses electric current with electric current and one second test, this current source is exported this first test respectively at this very first time and this second time and is flow to this LED element with electric current and this second test electricity consumption, this first test is pulse current with electric current and this second test with electric current, this second test is big with the pulse width of electric current than this first test with the pulse width of electric current, and this first test equates with a load current value of this LED element with current value with current value and this second test.
8. the pick-up unit of LED package interface as claimed in claim 7, wherein this second test little by little increases pulse width with electric current, this current source provides this second test electricity consumption to flow to this LED element and this voltage check device are measured this LED element in order with electric current with this test a plurality of forward voltages in order, comprising this first forward voltage of measuring this LED element in this very first time, at this second forward voltage of this this LED element of second time measurement.
9. the pick-up unit of LED package interface as claimed in claim 1, wherein this at least one electric current comprises a heating and uses electric current with an electric current and a test, this current source flow to this LED element until this heating electricity consumption of heating interior output interval time before this very first time flow to this LED element and exports this test electricity consumption in this second time, wherein this heating is a pulse current with electric current and this test electric current, this heating is big with the pulse width of electric current than this test with the pulse width of electric current, this heating equates with a load current value of this LED element with current value with current value and this test, and should the very first time and interval time of this second time between between 100 microseconds to 1 second.
10. the pick-up unit of LED package interface as claimed in claim 9, wherein this current source provides this test electricity consumption to flow to this LED element in order, this voltage check device is measured a plurality of forward voltages of this LED element in order with electric current with this test, measure this first forward voltage of this LED element in this very first time, at this second forward voltage of this this LED element of second time measurement.
11. the pick-up unit of LED package interface as claimed in claim 1, wherein this at least one electric current comprises a heating and uses electric current with an electric current and a test, this test uses current value less than this heating current value, this electric current came from before this very first time to be exported this heating electricity consumption interval time in a heating and flow to this LED element and also export this test electricity consumption in this very first time and this second time respectively and flow to this LED element, wherein should heating equate with a load current value of this LED element with current value, this test with current value between 0.1 milliampere to 5 milliampere, and should the very first time and interval time of this second time between between 100 microseconds to 1 second.
12. the pick-up unit of LED package interface as claimed in claim 11, wherein this current source provides this test electricity consumption to flow to this LED element in order, this voltage check device is measured a plurality of forward voltages of this LED element in order with electric current with this test, measure this first forward voltage of this LED element in this very first time, at this second forward voltage of this this LED element of second time measurement.
13. the pick-up unit of LED package interface as claimed in claim 1, wherein this LED element comprises a led chip and a package carrier, and this package interface comprises and is formed at the solid brilliant interface of one between this led chip and this package carrier.
14. the pick-up unit of LED package interface as claimed in claim 13, wherein this LED element also comprises a circuit board, and this package interface also comprises and is formed at one between this package carrier and this circuit board assembling interface.
15. the pick-up unit of LED package interface as claimed in claim 1, wherein the resolution of this voltage check device is less than 5 millivolts (mV), and the sampling rate per second is higher than 200,000 times.
16. the detection method of a LED package interface, the method includes the steps of:
Provide at least one electric current to this LED element;
Utilize this electric current to measure one first forward voltage of this LED element in a very first time, and in one second forward voltage of one second this LED element of time measurement;
Calculate this first and a voltage difference of this second forward voltage; And
Judge that then this LED element is judged to be inefficacy when this voltage difference is preset the inefficacy decision content greater than one.
17. the detection method of LED package interface as claimed in claim 16, wherein this electric current is a test electric current, utilize this electric current to measure a plurality of forward voltages of this LED element in order, a plurality of forward voltages of this of this LED element comprise this first forward voltage and this second forward voltage.
18. the detection method of LED package interface as claimed in claim 17, wherein this current value equates with a load current value of this LED element.
19. the detection method of LED package interface as claimed in claim 16, wherein should the very first time and interval time of this second time between between 100 microseconds to 1 second.
20. the detection method of LED package interface as claimed in claim 16, wherein this at least one electric current comprises a test and uses electric current with an electric current and a heating, this the test with current value between 0.1 milliampere (mA) between 5 milliamperes, this heating equates with a load current value of this LED element with current value, provide this test electricity consumption to flow to this LED element in this very first time and this second time, heating before this second time provides this heating electricity consumption to flow to this LED element the interval time, and this heats interval time between between 100 microseconds to 1 second.
21. the detection method of LED package interface as claimed in claim 20, wherein this test alternatively provides to this LED element with electric current with electric current and this heating, utilize this test to measure a plurality of forward voltages of this LED element in order with electric current, a plurality of forward voltages of this of this LED element comprise this first forward voltage and this second forward voltage.
22. the detection method of LED package interface as claimed in claim 16, wherein this at least one electric current comprises one first test and uses electric current with electric current and one second test, this first test provides to this LED element for a pulse current and in this very first time with electric current, this second test provides to this LED element for a pulse current and in this second time with electric current, this second test is big with the pulse width of electric current than this first test with the pulse width of electric current, and this first test equates with a load current value of this LED element with current value with current value and this second test.
23. the detection method of LED package interface as claimed in claim 22, wherein this second test little by little increases pulse width with electric current, utilize this test to measure a plurality of forward voltages of this LED element in order with electric current, a plurality of forward voltages of this of this LED element comprise this first forward voltage and this second forward voltage.
24. the detection method of LED package interface as claimed in claim 16, wherein this at least one electric current comprises a heating and uses electric current with an electric current and a test, heating before this very first time provides this heating electricity consumption to flow to this LED element in interval time and provides this test electricity consumption to flow to this LED element in this second time, wherein this test is a pulse current with electric current and this heating electric current, this heating is big with the pulse width of electric current than this test with the pulse width of electric current, this heating equates with a load current value of this LED element with current value with current value and this test, and should the very first time and interval time of this second time between between 100 microseconds to 1 second.
25. the detection method of LED package interface as claimed in claim 24, wherein provide this test electricity consumption to flow to this LED element in order, utilize this test to measure a plurality of forward voltages of this LED element in order with electric current, a plurality of forward voltages of this of this LED element comprise this first forward voltage and this second forward voltage.
26. the detection method of LED package interface as claimed in claim 16, wherein this at least one electric current comprises a heating and uses electric current with an electric current and a test, this test uses current value less than this heating current value, heating before this very first time provides this heating electricity consumption to flow to this LED element in interval time, provide this test electricity consumption to flow to this LED element in this very first time and this second time, wherein should heating equate with a load current value of this LED element with current value, this test with current value between 0.1 milliampere to 5 milliampere, and should the very first time and interval time of this second time between between 100 microseconds to 1 second.
27. the detection method of LED package interface as claimed in claim 26, wherein provide this test electricity consumption to flow to this LED element in order, utilize this test to measure a plurality of forward voltages of this LED element in order with electric current, a plurality of forward voltages of this of this LED element comprise this first forward voltage and this second forward voltage.
28. the detection method of LED package interface as claimed in claim 16, wherein this LED element comprises a led chip and a package carrier, and this package interface comprises and is formed at the solid brilliant interface of one between this led chip and this package carrier.
29. the detection method of LED package interface as claimed in claim 28, wherein this LED element also comprises a circuit board, and this package interface also comprises and is formed at one between this package carrier and this circuit board assembling interface.
30. the detection method of a plurality of LED package interfaces, the method includes the steps of:
At least one electric current is provided;
Utilize this electric current to measure one first forward voltage of each LED element in a very first time, and in one second forward voltage of one second each LED element of time measurement;
Calculate each LED element this first and a voltage difference of this second forward voltage; And
These these a plurality of LED elements of voltage difference classification according to this each a plurality of LED element.
31. the detection method of a plurality of LED package interfaces as claimed in claim 30, this very first time of wherein measuring this each a plurality of LED element equates, this second time of measuring this each LED element equates.
32. a computer program that is used to detect the package interface of a LED element comprises a computer read/write memory medium that contains computer-readable medium instruction, this computer-readable medium instruction comprises:
One first instruction provides at least one electric current to this LED element;
One second instruction utilizes this at least one electric current to measure one first forward voltage of this LED element and in one second forward voltage of one second this LED element of time measurement in a very first time;
One the 3rd instruction, calculate this first and a voltage difference of this second forward voltage; And
One the 4th instruction judges that then this LED element is judged to be inefficacy when this voltage difference is preset the inefficacy decision content greater than one.
33. computer program as claimed in claim 32, wherein this at least one electric current is a long duration current, utilize this at least one electric current to measure a plurality of forward voltages of this LED element in order, a plurality of forward voltages of this of this LED element comprise this first forward voltage and this second forward voltage.
34. computer program as claimed in claim 33, wherein this at least one current value equates with a load current value of this LED element.
35. computer program as claimed in claim 32, wherein should the very first time and interval time of this second time between between 100 microseconds to 1 second.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201010000868.3 | 2010-01-19 | ||
| US12/823,859 | 2010-06-25 | ||
| US12/823,859 US20110133769A1 (en) | 2009-12-09 | 2010-06-25 | Inspection apparatus and method for led package interface |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102183546A true CN102183546A (en) | 2011-09-14 |
| CN102183546B CN102183546B (en) | 2014-12-24 |
Family
ID=44583568
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201110007730.0A Active CN102183546B (en) | 2010-01-19 | 2011-01-14 | Detection device and method for package interface of light emitting diode |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102183546B (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102693925A (en) * | 2011-03-25 | 2012-09-26 | 夏普株式会社 | Temperature characteristic detection apparatus of semiconductor light emitting element and temperature characteristic detection method |
| CN107797499A (en) * | 2017-11-30 | 2018-03-13 | 佛山科学技术学院 | A kind of pulsed programmable power supply and control method |
| CN111965515A (en) * | 2020-10-21 | 2020-11-20 | 深圳市永联科技股份有限公司 | Method for identifying fault of reverse-filling prevention diode |
| CN112858887A (en) * | 2021-01-18 | 2021-05-28 | 昂宝电子（上海）有限公司 | Layered defect detection method for integrated circuit package |
| CN114664704A (en) * | 2022-03-18 | 2022-06-24 | 东莞市中麒光电技术有限公司 | LED chip screening method and display screen |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10300811A (en) * | 1997-04-21 | 1998-11-13 | Canon Inc | Measuring method of led dc thermal resistance, and measuring device thereof |
| US20040178808A1 (en) * | 2003-03-13 | 2004-09-16 | Intel Corporation | Thermal stratification test apparatus and method providing cyclical and steady-state stratified environments |
| CN1544954A (en) * | 2003-11-14 | 2004-11-10 | 佛山市国星光电科技有限公司 | Method for testing power type LED thermal resistance and special purpose chip thereof |
| US20080174333A1 (en) * | 2007-01-22 | 2008-07-24 | Jun-Pyo Hong | Test sockets having peltier elements, test equipment including the same and methods of testing semiconductor packages using the same |
| CN101252099A (en) * | 2008-03-18 | 2008-08-27 | 日月光半导体制造股份有限公司 | Temperature circulating test device for heating chip upside-down mounting encapsulation structure |
-
2011
- 2011-01-14 CN CN201110007730.0A patent/CN102183546B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10300811A (en) * | 1997-04-21 | 1998-11-13 | Canon Inc | Measuring method of led dc thermal resistance, and measuring device thereof |
| US20040178808A1 (en) * | 2003-03-13 | 2004-09-16 | Intel Corporation | Thermal stratification test apparatus and method providing cyclical and steady-state stratified environments |
| CN1544954A (en) * | 2003-11-14 | 2004-11-10 | 佛山市国星光电科技有限公司 | Method for testing power type LED thermal resistance and special purpose chip thereof |
| US20080174333A1 (en) * | 2007-01-22 | 2008-07-24 | Jun-Pyo Hong | Test sockets having peltier elements, test equipment including the same and methods of testing semiconductor packages using the same |
| CN101252099A (en) * | 2008-03-18 | 2008-08-27 | 日月光半导体制造股份有限公司 | Temperature circulating test device for heating chip upside-down mounting encapsulation structure |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102693925A (en) * | 2011-03-25 | 2012-09-26 | 夏普株式会社 | Temperature characteristic detection apparatus of semiconductor light emitting element and temperature characteristic detection method |
| CN107797499A (en) * | 2017-11-30 | 2018-03-13 | 佛山科学技术学院 | A kind of pulsed programmable power supply and control method |
| CN107797499B (en) * | 2017-11-30 | 2023-10-31 | 佛山科学技术学院 | Pulse type program-controlled power supply and control method |
| CN111965515A (en) * | 2020-10-21 | 2020-11-20 | 深圳市永联科技股份有限公司 | Method for identifying fault of reverse-filling prevention diode |
| CN112858887A (en) * | 2021-01-18 | 2021-05-28 | 昂宝电子（上海）有限公司 | Layered defect detection method for integrated circuit package |
| CN114664704A (en) * | 2022-03-18 | 2022-06-24 | 东莞市中麒光电技术有限公司 | LED chip screening method and display screen |
Also Published As
| Publication number | Publication date |
|---|---|
| CN102183546B (en) | 2014-12-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105486992B (en) | A kind of online health controller and method of insulated gate bipolar transistor | |
| CN102183546A (en) | Detection device and method for package interface of light emitting diode | |
| Ji et al. | In situ diagnostics and prognostics of solder fatigue in IGBT modules for electric vehicle drives | |
| CN1853111B (en) | Temperature control device and temperature control method, Electronic component test device and method and processor | |
| US20110133769A1 (en) | Inspection apparatus and method for led package interface | |
| US20120217976A1 (en) | Circuit for detection of failed solder-joints on array packages | |
| US20150276854A1 (en) | Integrated circuit interconnect crack monitor circuit | |
| CN105185889A (en) | Naked crystal encapsulation adjustable photoelectric LED lighting assembly and manufacturing process | |
| Tran et al. | Constant δt j power cycling strategy in DC mode for top-metal and bond-wire contacts degradation investigations | |
| Kurukuru et al. | Condition monitoring of IGBT modules using online TSEPs and data‐driven approach | |
| CN104880657A (en) | IGBT device fault detection method and corresponding detection circuit | |
| US20120039045A1 (en) | Power module and method for detecting insulation degradation thereof | |
| Elger et al. | Inline thermal transient testing of high power LED modules for solder joint quality control | |
| Long et al. | Wire loss monitoring in ultrasonic wedge bonding using the Kalman filter algorithm | |
| CN106093531A (en) | A kind of chip dynamic voltage down detection circuit and detection method | |
| Magnien et al. | Parameter driven monitoring for a flip-chip LED module under power cycling condition | |
| EP3304731B1 (en) | Method for testing the die-attach of a photovoltaic cell assembly | |
| CN100530578C (en) | Production of long-lead, low-arc and high-density golden-wire ball welding | |
| CN109270381A (en) | The load of four tunnel independent electronics controls and measures junction temperature system and its junction temperature measurement method | |
| Magnien et al. | Temperature sensitive electrical parameter sensing unit for early failure detection | |
| CN203929942U (en) | Circuit board device for fast detecting | |
| CN100460867C (en) | Method for detecting package material reliability of plastic package chip carrier device with leads | |
| Annaniah et al. | Investigation on thermal resistance of cracked AlInGaP die substrate and in-line die crack testing method | |
| US9341669B2 (en) | Testing apparatus | |
| CN105698137A (en) | MOSFET-containing system-in-package LED lighting driving power assembly and manufacturing process |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |