CN108181566A - The quick detection recognition method of LED luminescence chips - Google Patents
The quick detection recognition method of LED luminescence chips Download PDFInfo
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- CN108181566A CN108181566A CN201711468808.2A CN201711468808A CN108181566A CN 108181566 A CN108181566 A CN 108181566A CN 201711468808 A CN201711468808 A CN 201711468808A CN 108181566 A CN108181566 A CN 108181566A
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- semi
- junction
- light source
- luminescence chips
- led luminescence
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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
Abstract
The invention discloses the quick detection recognition methods of LED luminescence chips, it controls light source transmitting excitation light beam transmitted through semi-transparent/semi-reflective mirror group by detecting control and signal acquisition process unit, it is radiated on the PN junction of LED chip to be measured, semi-transparent/semi-reflective mirror group is again by the spontaneous transient state light reflection formed on PN junction to convergent lens group, light beam is converged to photoelectric converter by convergent lens group again, photoelectric converter converts optical signals into electric signal, is sent into detection control and signal acquisition process unit calculates photogenerated current A be pn-junction area, LnAnd LpRespectively electronics, hole diffusion length,Represent the average luminous intensity calculated with number of photons, if LED luminescence chips are same color same type and function is intact, photogenerated current is equal, and photogenerated current value is 0 if LED luminescence chips damage.The present invention can realize the batch detection to LED luminescence chips, efficiency greatly improves by above-mentioned principle.
Description
Technical field
The present invention relates to detection fields, and in particular to the quick detection recognition method of LED luminescence chips.
Background technology
LED (Light Emitting Diode) with its it is intrinsic the characteristics of, such as power saving, long lifespan, vibration resistance, response speed
Soon, the features such as cold light source, it is widely used in the fields such as indicator light, signal lamp, display screen, Landscape Lighting, but due to various originals
Because LED illumination can't universalness, be the principal element for restricting LED illumination light source universalness wherein expensive, and LED chip
Encapsulation be LED finished products production prime cost source, be only improved encapsulation after yield rate, the production of LED product could be reduced
Cost, the chip detection before encapsulating in this way are exactly a necessary process of LED batch productions.Existing LED detections are every
Secondary to detect a LED luminescence chip, detection speed is slow, and efficiency is low.
Invention content
The present invention overcomes the deficiencies in the prior art, provide LED luminescence chips quick detection recognition method, can realize pair
The batch detection of LED luminescence chips, efficiency greatly improve.
To solve the technical issues of above-mentioned, the present invention uses following technical scheme：LED luminescence chips quickly detect identification side
Method, it controls light source transmitting excitation light beam to be shone transmitted through semi-transparent/semi-reflective mirror group by detecting control and signal acquisition process unit
It penetrates on the PN junction of LED chip to be measured, semi-transparent/semi-reflective mirror group is again by the spontaneous transient state light reflection formed on PN junction to convergent lens
Light beam is converged to photoelectric converter by group, convergent lens group again, and photoelectric converter converts optical signals into electric signal, is sent into detection
Control and signal acquisition process unit calculate photogenerated currentA is pn-junction area, and q is the electricity of electronics
Amount, w are potential barrier sector widths, LnAnd LpRespectively electronics, hole diffusion length, β is quantum yield, i.e., often absorb a photon
The electron-hole logarithm of generation, β are not more than 1,The average luminous intensity calculated with number of photons is represented, if LED luminescence chips are phase
With color same type and function it is intact, then photogenerated current is equal, if LED luminescence chips damage if photogenerated current value be 0.
According to pn-junction photovoltaic effect, when irradiating non-homogeneous semiconductor with the light of appropriate wavelength, due to built in field
Effect, electromotive force is generated inside semiconductor, for pn-junction, the carrier that illumination generates respectively moves round about, can exist
The photogenerated current from n areas is formed in pn-junction.This photoelectric effect as caused by built in field, referred to as photovoltaic effect.We
Case controls light source transmitting excitation light beam first transmitted through semi-transparent microscope group, then be radiated at by detecting control and signal acquisition process unit
On the PN junction of LED chip to be measured, semi-transparent/semi-reflective mirror group again by the spontaneous transient state light reflection formed on PN junction to convergent lens group,
Light beam is converged to photoelectric converter by convergent lens group again, and photoelectric converter converts optical signals into electric signal, is sent into detection control
System and signal acquisition process unit are handled, and photogenerated current are calculated by detection control unit, to realize the inspection to LED chip
It surveys.If LED luminescence chips are same color same type and function is intact, photogenerated current is equal and is not zero, if LED shines
Then photogenerated current value is 0 to wafer damage.So as to fast and accurately realize the detection to LED luminescence chips, testing result is quickly accurate
Really.For can then be carried out at the same time detection with batch of LED luminescence chips, testing result is identical and is not zero, then shows correctly,
The batch detection to LED luminescence chips is realized, efficiency greatly improves.
Preferably, the calculation formula of average luminous intensity isD is the thickness of pn-junction, and α is semiconductor material
The absorption coefficient of material, P (x) are the excitation luminous intensities at the x of position in pn-junction, it is assumed that pn-junction surface coordinate position for 0, P (x)=
P0e-ax, P0It is the excitation luminous intensity on pn-junction surface.
Preferably, the excitation light beam is pulsed light；The detection control and signal acquisition process unit control light source hair
Penetrate excitation light beam vertical incidence it is semi-transparent/semi-reflective mirror group, transmitted through semi-transparent/semi-reflective mirror group beam orthogonal be radiated at it is described to be measured
On the PN junction of LED chip.
Preferably, it is described detection control and signal acquisition process unit include signal conditioning circuit, analog/digital conversion circuit,
CPU, pn-junction area detecting module, barrier region width detection module, quantum yield detection module, electron charge detection module, electricity
Son, the diffusion length detection module in hole, display, light source control Waveform generating circuit and light source driving circuit；Wherein signal
The output terminal of modulate circuit is connected with the input terminal of analog/digital conversion circuit；The input of the output terminal and CPU of analog/digital conversion circuit
End is connected；The output terminal of the CPU input terminal phase with analog/digital conversion circuit, light source control Waveform generating circuit and display respectively
Even；The output terminal of light source control Waveform generating circuit is connected with the input terminal of light source driving circuit；During work, signal conditioning circuit
It being electrically connected with photoelectric converter, light source driving circuit control light source generates excitation light beam and is radiated on the PN junction of LED chip to be measured,
Pn-junction area detecting module, barrier region width detection module, quantum yield detection module, electron charge detection module and electronics,
The diffusion length detection module in hole is connect with CPU.
Compared with prior art, the beneficial effects of the invention are as follows：Photogenerated current is calculated by detection control unit, to realize
Detection to LED chip, if LED luminescence chips for same color same type and function it is intact, photogenerated current is equal and not
It is zero, photogenerated current value is 0 if LED luminescence chips damage；So as to fast and accurately realize the detection to LED luminescence chips,
Testing result is quick and precisely；For can then be carried out at the same time detection with batch of LED luminescence chips, testing result is identical and is not
Zero, then show correctly, to realize the batch detection to LED luminescence chips, efficiency greatly improves.
Description of the drawings
Fig. 1 is the structural diagram of the present invention.
Fig. 2 is the functional block diagram of detection control and signal acquisition process unit in Fig. 1.
Specific embodiment
The present invention is further elaborated below in conjunction with the accompanying drawings, and embodiments of the present invention are not limited thereto.
Embodiment 1：
As shown in Figs. 1-2, the present invention includes the quick detection recognition method of LED luminescence chips, it controls and believe by detecting
Number acquisition process unit 9 controls the transmitting excitation light beam 4 of light source 7 to be radiated at LED chip 2 to be measured transmitted through semi-transparent/semi-reflective mirror group 12
PN junction 1 on, the spontaneous transient state light 3 formed on PN junction 1 is reflexed to convergent lens group 6 by semi-transparent/semi-reflective mirror group 12 again, is assembled saturating
Light beam is converged to photoelectric converter 8 by microscope group 6 again, and photoelectric converter 8 converts optical signals into electric signal, be sent into detection control and
Signal acquisition process unit 9 calculates photogenerated currentA is pn-junction area, and q is the electricity of electronics, and w is potential barrier
Sector width, LnAnd LpRespectively electronics, hole diffusion length, β is quantum yield, i.e., often absorb electronics that photon generates-
Hole logarithm, β are not more than 1,The average luminous intensity calculated with number of photons is represented, if LED luminescence chips are mutually similar for same color
Type and function is intact, then photogenerated current is equal, and photogenerated current value is 0 if LED luminescence chips damage.
When light is radiated on PN junction, the photon that energy is more than energy gap can excite Intrinsic Gettering, be generated on the both sides of knot
Electron hole pair.Since PN junction barrier region is there are stronger built in field, the photogenerated minority carriers for tying both sides are made by this
With respectively being moved to other side's region direction.The electronics in p areas is moved to n areas, and the hole in n areas is moved to p areas, reduces PN junction
Potential barrier then forms photo-induced voltage at PN junction both ends, this is the photovoltaic effect of PN junction.When PN junction is constantly in open circuit shape
State and when being irradiated by light, photogenerated charge can be accumulated in barrier region, and PN junction is made to show capacitance characteristic.The reduction of potential barrier destroys
Original balance between carrier diffusion movement and drift motion inside PN junction.When the flow currents density of photo-generated carrier and more
When the diffusion current density of number carrier is equal, stable potential difference Voc is set up on PN junction both sides, at this point, photo-generated carrier
Generation rate is equal to the recombination rate of electron hole pair.If illumination does not stop, photo-generated carrier constantly generates, and electron hole pair can not yet
It is disconnected compound, it is compound to cause shining for LED PN junctions.Therefore under static light irradiation, as long as illumination does not stop, PN junction has
Lasting self-luminous.However, the electromotive force that illumination generates is limited always, if less than the dead zone voltage of diode, it is positive
Electric current is very small, and the luminous intensity of LED also will be very weak, it may not be possible to be detected.According to the voltage-current characteristic of PN junction,
After forward bias is more than threshold value (being equal to dead zone voltage value), forward current (how sub- current density) increases with bias voltage index
Add.If using the photo-induced voltage that constant illumination generates as the DC offset voltage of LED, and an alternating magnetic field is utilized to LED
A small alternating voltage is provided, then the peak value of how sub- diffusion flow will greatly improve, and luminous peak strength also can accordingly
It greatly enhances.And by the exchange intervention of alternating magnetic field, shining for alternation can be generated, it can be with excitation light (direct current) from frequency
It distinguishes.
According to pn-junction photovoltaic effect, when irradiating non-homogeneous semiconductor with the light of appropriate wavelength, due to built in field
Effect, electromotive force is generated inside semiconductor, for pn-junction, the carrier that illumination generates respectively moves round about, can exist
The photogenerated current from n areas is formed in pn-junction.This photoelectric effect as caused by built in field, referred to as photovoltaic effect.We
Case controls light source transmitting excitation light beam first transmitted through semi-transparent microscope group, then be radiated at by detecting control and signal acquisition process unit
On the PN junction of LED chip to be measured, semi-transparent/semi-reflective mirror group again by the spontaneous transient state light reflection formed on PN junction to convergent lens group,
Light beam is converged to photoelectric converter by convergent lens group again, and photoelectric converter converts optical signals into electric signal, is sent into detection control
System and signal acquisition process unit are handled, and photogenerated current are calculated by detection control unit, to realize the inspection to LED chip
It surveys.If LED luminescence chips are same color same type and function is intact, photogenerated current is equal and is not zero, if LED shines
Then photogenerated current value is 0 to wafer damage.So as to fast and accurately realize the detection to LED luminescence chips, testing result is quickly accurate
Really.For can then be carried out at the same time detection with batch of LED luminescence chips, testing result is identical and is not zero, then shows correctly,
The batch detection to LED luminescence chips is realized, efficiency greatly improves.
Embodiment 2：
The present embodiment is preferably as follows on the basis of embodiment 1：The calculation formula of average luminous intensity isD is the thickness of pn-junction, and α is the absorption coefficient of semi-conducting material, and Px is the swashing at the x of position in pn-junction
Encourage luminous intensity, it is assumed that pn-junction surface coordinate position is 0, Px=P0e-ax, P0It is the excitation luminous intensity on pn-junction surface.
The excitation light beam 4 is pulsed light；The detection control and signal acquisition process unit 9 control the transmitting of light source 7 to swash
Encourage 4 vertical incidence of light beam it is semi-transparent/semi-reflective mirror group 12, transmitted through semi-transparent/semi-reflective mirror group 12 beam orthogonal be radiated at it is described to be measured
On the PN junction 1 of LED chip 2.
Detection control and signal acquisition process unit include signal conditioning circuit, analog/digital conversion circuit, CPU, pn-junction area
The diffusion of detection module, barrier region width detection module, quantum yield detection module, electron charge detection module, electronics, hole
Length detection module, display, light source control Waveform generating circuit and light source driving circuit；The wherein output of signal conditioning circuit
End is connected with the input terminal of analog/digital conversion circuit；The output terminal of analog/digital conversion circuit is connected with the input terminal of CPU；CPU's is defeated
Input terminal of the outlet respectively with analog/digital conversion circuit, light source control Waveform generating circuit and display is connected；Light source control waveform
The output terminal of generation circuit is connected with the input terminal of light source driving circuit；During work, signal conditioning circuit and photoelectric converter electricity
Connection, light source driving circuit control light source generate excitation light beam 4 and are radiated on the PN junction 1 of LED chip 2 to be measured, the inspection of pn-junction area
Survey module, barrier region width detection module, quantum yield detection module, electron charge detection module and electronics, the diffusion in hole
Length detection module is connect with CPU.Pn-junction area detecting module, barrier region width detection module, quantum production in this programme
Volume detection module, electron charge detection module and electronics, hole diffusion length detection module measure pn-junction area successively, q is
The electricity of electronics, w are potential barrier sector widths, LnAnd LpRespectively electronics, hole diffusion length, β is quantum yield, i.e., often absorbs
Then the electron-hole logarithm that one photon generates carries out data calculation processing so as to obtain photogenerated current, then compares
To final judging result.
The invention can be realized as described above.
Claims (4)
- The quick detection recognition method of 1.LED luminescence chips, it is characterised in that：It is by detecting control and signal acquisition process unit (9) control light source (7) emits excitation light beam (4) transmitted through semi-transparent/semi-reflective mirror group (12), is radiated at the PN of LED chip to be measured (2) It ties on (1), semi-transparent/semi-reflective mirror group (12) and the spontaneous transient state light (3) formed on PN junction (1) is reflexed into convergent lens group (6), Light beam is converged to photoelectric converter (8) by convergent lens group (6) again, and photoelectric converter (8) converts optical signals into electric signal, send Enter detection control and signal acquisition process unit (9) calculates photogenerated currentA is pn-junction area, and q is The electricity of electronics, w are potential barrier sector widths, LnAnd LpRespectively electronics, hole diffusion length, β is quantum yield, i.e., often absorbs The electron-hole logarithm that one photon generates, β are not more than 1,The average luminous intensity calculated with number of photons is represented, if LED shines Chip is same color same type and function is intact, then photogenerated current is equal, the photogenerated current value if LED luminescence chips damage It is 0.
- 2. the quick detection recognition method of LED luminescence chips according to claim 1, it is characterised in that:Average luminous intensity Calculation formula isD is the thickness of pn-junction, and α is the absorption coefficient of semi-conducting material, and P (x) is in pn-junction Excitation luminous intensity at the x of position, it is assumed that pn-junction surface coordinate position is 0, P (x)=P0e-ax, P0It is the excitation light on pn-junction surface Intensity.
- 3. the quick detection recognition method of LED luminescence chips according to claim 1, it is characterised in that：The excitation light beam (4) it is pulsed light；The detection control and signal acquisition process unit (9) control light source (7) emit excitation light beam (4) and vertically enter Semi-transparent/semi-reflective mirror group (12) is penetrated, the beam orthogonal transmitted through semi-transparent/semi-reflective mirror group (12) is radiated at the LED chip to be measured (2) PN junction (1) on.
- 4. the quick detection recognition method of LED luminescence chips according to profit requires 1, it is characterised in that：It is described detection control and Signal acquisition process unit is wide including signal conditioning circuit, analog/digital conversion circuit, CPU, pn-junction area detecting module, barrier region Spend detection module, quantum yield detection module, electron charge detection module, electronics, the diffusion length detection module in hole, display Device, light source control Waveform generating circuit and light source driving circuit；The wherein output terminal of signal conditioning circuit and analog/digital conversion circuit Input terminal be connected；The output terminal of analog/digital conversion circuit is connected with the input terminal of CPU；The output terminal of CPU turns respectively with analog/digital Change circuit, light source control Waveform generating circuit is connected with the input terminal of display；The output terminal of light source control Waveform generating circuit It is connected with the input terminal of light source driving circuit；During work, signal conditioning circuit is electrically connected with photoelectric converter, light source driving circuit Control light source generates excitation light beam (4) and is radiated on the PN junction (1) of LED chip to be measured (2), pn-junction area detecting module, potential barrier Sector width detection module, quantum yield detection module, electron charge detection module and electronics, the diffusion length detection module in hole It is connect with CPU.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201711468808.2A CN108181566A (en) | 2017-12-29 | 2017-12-29 | The quick detection recognition method of LED luminescence chips |
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| CN201711468808.2A CN108181566A (en) | 2017-12-29 | 2017-12-29 | The quick detection recognition method of LED luminescence chips |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112098786A (en) * | 2019-05-29 | 2020-12-18 | 中国科学院半导体研究所 | On-line comprehensive test system and method suitable for optical communication light-emitting device |
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| CN112098786A (en) * | 2019-05-29 | 2020-12-18 | 中国科学院半导体研究所 | On-line comprehensive test system and method suitable for optical communication light-emitting device |
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Application publication date: 20180619 |