CN1330970C - Method for testing power type LED thermal resistance and special purpose chip thereof - Google Patents
Method for testing power type LED thermal resistance and special purpose chip thereof Download PDFInfo
- Publication number
- CN1330970C CN1330970C CNB200310112158XA CN200310112158A CN1330970C CN 1330970 C CN1330970 C CN 1330970C CN B200310112158X A CNB200310112158X A CN B200310112158XA CN 200310112158 A CN200310112158 A CN 200310112158A CN 1330970 C CN1330970 C CN 1330970C
- Authority
- CN
- China
- Prior art keywords
- type led
- power
- chip
- unit
- designed
- 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.)
- Expired - Fee Related
Links
Images
Landscapes
- Led Devices (AREA)
- Testing Or Measuring Of Semiconductors Or The Like (AREA)
Abstract
The present invention relates to a method for testing power type LED thermal resistance and a special purpose chip thereof. The present invention is mainly characterized in that the special purpose chip is used for simulating a designed power type LED chip, and the special purpose chip has the same epitaxial layer and electrode layer structures with the designed power type LED chip; when the special purpose chip is used for making a power type LED to be tested, the same or similar packaging technology with a designed power type LED is adopted. The present invention can accurately simulate the thermal characteristic of the designed power type LED to obtain the thermal resistance of the designed power type LED through measuring and calculating without adopting expensively special-purpose testing instruments, and therefore, the present invention reduces the research and development cost of the power type LED.
Description
Technical field
The present invention relates in design or improve in the process of power-type LED, the technology that the heat resistance characteristic of power-type LED device is accurately measured.
Background technology
Power-type LED, that is power type light-emitting diode, its power input is several times of common LED, tens times, even might reach thousands of times of hundreds ofs, for the heat that the power-type LED course of work is produced in time distributes, temperature during guaranteed output type LED work is within allowed band, make the power-type LED can high-level efficiency, long-term work highly reliably, require the power-type LED device to have very little thermal resistance, this just need or improve the power-type LED encapsulating structure in design, encapsulating material, in the process of packaging technology, constantly measure the thermal resistance of power-type LED, estimate the new influence that designs or improve thermal resistance.
Traditional power-type LED thermo-resistance measurement method has direct method and indirect method usually.The common ground of these two kinds of methods all is to have made power-type LED earlier, and then it is measured.The difference of two kinds of methods is: direct method adopts the material of known radiation coefficient to cover the chip of power-type LED, after the chip energising, measure junction temperature by emittance, perhaps cover chip with liquid crystal, after the chip energising, color according to the test liquid crystal is measured chip temperature, this method needs the very expensive special test equipment of price, in test process, need the encapsulating material of power-type LED is removed, it is very complicated to operate, remove the radiator structure that encapsulating material has also destroyed device itself, influenced the accuracy of test; Indirect method also claims electric method, mainly be when utilizing constant-current driving, PN junction forward voltage drop and variation of temperature relation, during measurement, at first pass to small-pulse effect and detect electric current to chip, measure the forward voltage drop of PN junction this moment, then chip current is become running current, after waiting to reach thermal equilibrium, again working current is changed into and aforementioned pulse detection current amplitude and the identical detection electric current of pulsewidth, measure the forward voltage drop of PN junction,, obtain the PN junction temperature rise of chip in conjunction with forward voltage drop and variation of temperature relation according to the difference of front and back test forward voltage drop, and further obtain the thermal resistance value of power-type LED, though this method is not destroyed the encapsulating structure of device, its major defect is that thermal loss causes the test error of thermal resistance bigger in the current conversion process, and what record with the pulse detection electric current may be transient thermal resistance, different with actual conditions, moreover detecting the forward voltage drop of pulse current on PN junction also needs special-purpose testing tool, is difficult to reduce R﹠D costs.
Summary of the invention
The method that the purpose of this invention is to provide a kind of new measured power type LED thermal resistance, and the special chip that is used for this method adopt this method and special chip can improve the accuracy of measurement, and can reduce the R﹠D costs of power-type LED.
For achieving the above object, method of testing provided by the invention may further comprise the steps:
A, manufacturing special chip, this chip has following characteristics: be integrated with two LED unit in the chip, the epitaxial loayer of two unit is identical with electrode layer structure, and all power-type LED epitaxial loayer and the electrode layer structure with designed is identical, the area of one of them unit and designed power-type LED chip area are approaching, as heating unit, the area of another unit is less, as detecting unit;
B, this special chip is encapsulated, make power-type LED to be tested, packaging technology that is adopted and designed power-type LED are same or similar, make power-type LED to be tested and designed power-type LED, except chip structure many a detecting unit, and outside the pin that increases therefrom, identical as far as possible in others;
C, this power-type LED to be tested is measured, at first pass to a little steady current to detecting unit, measure the forward voltage drop of this moment, on heating unit, pass to constant heating current then, the heating current value is identical with designed power-type LED working current, the heating situation when being used for simulating designed power-type LED chip operation, reach thermal equilibrium after, measure the forward voltage drop and the heating current of heating unit, and measure the forward voltage drop of detecting unit once more;
D, according to the variation of detecting unit forward voltage drop before and after the heating, obtain the temperature change value of detecting unit PN junction in conjunction with forward voltage drop and variation of temperature relation, again by this temperature change value, obtain the thermal resistance of power-type LED according to the definition of thermal resistance.
By above-mentioned steps and the special chip structure that adopted as seen, the key difference point of the present invention and conventional test methodologies is, conventional test methodologies is to make good designed power-type LED earlier, again it is measured, and the present invention simulates designed power-type LED chip with special chip.Because special chip has identical epitaxial loayer and electrode layer structure with designed power-type LED chip, and heating unit area wherein and designed power-type LED chip area are approaching, when making power-type LED to be tested with this special chip, also adopted and the same or analogous packaging technology of designed power-type LED, therefore can utilize special chip accurately to simulate the thermal characteristics of designed power-type LED, by measuring, calculate the thermal resistance of designed power-type LED.In measuring process, because be applied on the detecting unit is less steady current, therefore its thermal value is very little to the heat distribution influence of whole special chip, and because the electric current that is applied on detecting unit and the heating unit is independent separately, there are not heating current and the transfer process that detects electric current, reduced test error, moreover, compare with the mode that adopts the pulse detection electric current, measuring the forward voltage drop of steady current on PN junction is more prone to, measurement result is also more accurate, and need not to adopt expensive special test equipment.This shows that the present invention has improved the accuracy of measured power type LED thermal resistance, and reduced the R﹠D costs of power-type LED.
The invention has the advantages that: can adopt with the identical manufacture craft of power-type LED chip and produce special chip, even can be when producing the power-type LED chip, produce special chip, being convenient to power-type LED factory makes voluntarily, perhaps by the mass production of chip manufacturing factory, to reach the purpose that reduces the special chip manufacturing cost, and need not expensive special test equipment in the measuring process, utilize reometer, common apparatus such as voltage table can be measured, not only reduced testing cost, and be convenient to operation, help power-type LED factory or relevant scientific research institution carry out power-type LED with lower cost product development and improvement.
Description of drawings
Fig. 1 is the adoptable electrode pattern embodiment 1 of special chip;
Fig. 2 is the circuit theory diagrams of Fig. 1;
Fig. 3 is the adoptable electrode pattern embodiment 2 of special chip;
Fig. 4 is the circuit theory diagrams of Fig. 3;
Fig. 5 is the adoptable electrode pattern embodiment 3 of special chip;
Fig. 6 is the circuit theory diagrams of Fig. 5;
Fig. 7 is the adoptable electrode pattern embodiment 4 of special chip;
Fig. 8 is the circuit theory diagrams of Fig. 7;
Fig. 9 is the adoptable electrode pattern embodiment 5 of special chip;
Figure 10 is the circuit theory diagrams of Fig. 9.
Embodiment
Below the present invention is described in further detail.
Method of testing may further comprise the steps:
A, produce special chip, integrated two LED unit in chip, all the power-type LED chip with designed is identical with electrode layer structure for the epitaxial loayer of two unit, that is layers of material component, structure, thickness etc. all the power-type LED chip with designed is identical, if designed power-type LED chip has various auxiliary layers, special chip also increases corresponding auxiliary layer so.A unit in two LED unit is a heating unit, the area of this unit should be approaching as far as possible with designed power-type LED chip area, purpose is in order to make this unit can bear higher electric current, and can simulate the heating situation of designed power-type LED as far as possible exactly.Another LED unit is a detecting unit, and the area of this unit should be as much as possible little, had better not surpass 1/4th of the special chip total area, to reduce the heat distribution influence of detecting unit to whole special chip as much as possible.Because special chip has identical epitaxial loayer and electrode layer structure with designed power-type LED chip, so can adopt with the identical manufacture craft of power-type LED chip and make.
B, special chip is encapsulated, make power-type LED to be tested.Packaging technology should be same or similar with designed power-type LED, make power-type LED to be tested and designed power-type LED, except chip structure many a detecting unit, and outside the pin that increases therefrom, in others, identical as far as possible as aspects such as encapsulating structure, encapsulating materials, its purpose also is in order to make power-type LED to be tested can simulate the heat resistance characteristic of designed power-type LED as far as possible exactly.
C, this power-type LED to be tested is measured.At first pass to a little steady current to detecting unit, for example the 1mA steady current is measured the forward voltage drop V of this moment
0, on heating unit, passing to constant heating current then, the heating current value is identical with designed power-type LED working current, the heating situation when simulating designed power-type LED chip operation with this.After reaching thermal equilibrium, measure the forward voltage drop V of heating unit
HWith heating current I
H, and measure the forward voltage drop V of detecting unit once more.Because the electric current that is applied on detecting unit and the heating unit is independent separately, therefore when measuring the forward voltage drop of detecting unit once more, need not to disconnect the electric current that is applied on the heating unit, to avoid thermal loss, improves accuracy of measurement.
D, according to the variation (V-V of detecting unit forward voltage drop before and after the heating
0), obtain the temperature change value (T-T of detecting unit PN junction in conjunction with forward voltage drop and variation of temperature relation
0).The theory of foundation is in certain temperature range herein, and the forward voltage drop of PN junction and PN junction temperature are approximate linear, are formulated as:
V＝V
0+K(T-T
0)
In the formula, V is the forward voltage drop of temperature when being T, V
0Be that temperature is T
0The time forward voltage drop, K is that forward voltage drop is with the variation of temperature coefficient.V, V that previous step is recorded suddenly
0This theoretical formula of value substitution can be tried to achieve the temperature change value (T-T of detecting unit PN junction
0).COEFFICIENT K can be demarcated acquisition by experiment.Because the forward voltage drop of PN junction and the linear relationship between the PN junction temperature are only set up in certain temperature range, when therefore practice was measured, environment temperature was preferably within the temperature range of calibration coefficient K.In order to try to achieve more precise dose changing value (T-T
0), also can adopt more complicated computing formula, for example increase secondary correction term, three correction terms of formula or adopt other forms of fitting formula etc., these formula all are the correction formulas that develops and form on the basis of above-mentioned theory formula.
Try to achieve the temperature change value (T-T of detecting unit PN junction
0) after, just can obtain the thermal resistance of power-type LED according to the definition of thermal resistance.For power-type LED, the computing formula of thermal resistance can be expressed as
In the formula, R is the power-type LED thermal resistance, and η is the electro-optical efficiency of power-type LED, and its value is the ratio of Output optical power and input electric power, and luminous power can record by light power meter.With (the T-T that had before calculated
0) value, and the V that records suddenly of previous step
H, I
HThis formula of value substitution can be tried to achieve the thermal resistance of power-type LED.
The epitaxial loayer of special chip of the present invention and electrode layer structure are to determine according to designed power-type LED chip, and consistent with designed power-type LED chip.The electrode of heating unit and detecting unit can be independent separately, also can adopt common cloudy connection or be total to positive connected mode.For the power-type LED to be tested that makes special chip and form with this special chip encapsulation, consistent with designed power-type LED as far as possible aspect heat resistance characteristic, the total area that preferably makes special chip is identical with the total area of designed power-type LED chip, and the electrode pattern of the heating unit of special chip is identical with the electrode pattern of designed power-type LED chip, can simulate the temperature distributing characteristic of designed power-type LED so better, make measurement result more accurate.
Fig. 1,3,5,7,9 has enumerated the adoptable several electrode patterns of special chip respectively.
In Fig. 1, the electrode shape of heating unit has adopted dielectric substrate power-type LED interdigited electrode commonly used. Numbering 1,2 is respectively the anode and the negative electrode of heating unit, and numbering 3,4 is respectively the anode and the negative electrode of detecting unit.The electrode of heating unit and detecting unit is independent separately, its circuit theory as shown in Figure 2,5 expression heating units wherein, 6 expression detecting units.
The negative electrode 2 that the difference of Fig. 3 and Fig. 1 only is heating unit links together with the negative electrode 4 of detecting unit, that is adopts cloudy connected mode altogether, its circuit theory as shown in Figure 4,5 expression heating units wherein, 6 expression detecting units.
In Fig. 5, the electrode position of heating unit is just opposite with Fig. 3, numbering 1 is the negative electrode of heating unit, numbering 2 is anodes of heating unit, the anode 2 of heating unit links together with the anode 4 of detecting unit, has adopted common positive connected mode, and its circuit theory as shown in Figure 6, wherein 5 represent heating units, 6 expression detecting units.
In Fig. 7, numbering 7 is anodes of heating unit, and this anode shape has adopted conductive substrates power-type LED " rice " shape electrode commonly used.Numbering 8 is anodes of detecting unit.Because the heating unit of present embodiment and the negative electrode of detecting unit link together and are arranged in other one deck, therefore do not have the negative electrode of heating unit and detecting unit in this one deck shown in Figure 7.The circuit theory of present embodiment as shown in Figure 8, wherein 5 the expression heating units, 6 the expression detecting units.
The difference of Fig. 9 and Fig. 7 only is that " rice " shape electrode is the negative electrode 9 of heating unit, and numbering 10 is negative electrodes of detecting unit.The electrode of heating unit and detecting unit adopts positive connected mode altogether, and is arranged in other one deck, does not therefore have the anode of heating unit and detecting unit in this one deck shown in this figure.Its circuit theory as shown in figure 10, wherein 5 the expression heating units, 6 the expression detecting units.
More than each embodiment be the adoptable several electrode patterns of special chip of the present invention, can also adopt other shape certainly in addition.In a word, the electrode pattern of the power-type LED chip that the electrode pattern of the heating unit of special chip is best and designed is identical, to obtain measurement result the most accurately.
Claims (3)
1, a kind of method of measured power type LED thermal resistance is characterized in that may further comprise the steps:
A, manufacturing special chip, this chip has following characteristics: be integrated with two LED unit in the chip, the epitaxial loayer of two unit is identical with electrode layer structure, and all power-type LED epitaxial loayer and the electrode layer structure with designed is identical, the area of one of them unit and designed power-type LED chip area are approaching, as heating unit, the area of another unit is less, as detecting unit;
B, this special chip is encapsulated, make power-type LED to be tested, packaging technology that is adopted and designed power-type LED are same or similar, make power-type LED to be tested and designed power-type LED, except chip structure many a detecting unit, and outside the pin that increases therefrom, identical as far as possible in others;
C, this power-type LED to be tested is measured, at first pass to a little steady current to detecting unit, measure the forward voltage drop of this moment, on heating unit, pass to constant heating current then, the heating current value is identical with designed power-type LED working current, the heating situation when being used for simulating designed power-type LED chip operation, reach thermal equilibrium after, measure the forward voltage drop and the heating current of heating unit, and measure the forward voltage drop of detecting unit once more;
D, according to the variation of detecting unit forward voltage drop before and after the heating, obtain the temperature change value of detecting unit PN junction in conjunction with forward voltage drop and variation of temperature relation, again by this temperature change value, obtain the thermal resistance of power-type LED according to the definition of thermal resistance.
2, a kind of special chip that is used for the described method of testing of claim 1, it is characterized in that: be integrated with two LED unit in the chip, the epitaxial loayer of two unit is identical with electrode layer structure, and all power-type LED epitaxial loayer and the electrode layer structure with designed is identical, the area of one of them unit and designed power-type LED chip area are approaching, as heating unit, the area of another unit is less, as detecting unit.
3, special chip as claimed in claim 2, the total area that it is characterized in that special chip is identical with the total area of designed power-type LED chip, and the electrode pattern of the heating unit of special chip is identical with the electrode pattern of designed power-type LED chip.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB200310112158XA CN1330970C (en) | 2003-11-14 | 2003-11-14 | Method for testing power type LED thermal resistance and special purpose chip thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB200310112158XA CN1330970C (en) | 2003-11-14 | 2003-11-14 | Method for testing power type LED thermal resistance and special purpose chip thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1544954A CN1544954A (en) | 2004-11-10 |
| CN1330970C true CN1330970C (en) | 2007-08-08 |
Family
ID=34336419
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB200310112158XA Expired - Fee Related CN1330970C (en) | 2003-11-14 | 2003-11-14 | Method for testing power type LED thermal resistance and special purpose chip thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1330970C (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101252099B (en) * | 2008-03-18 | 2012-03-28 | 日月光半导体制造股份有限公司 | Temperature circulating test device and heating chip upside-down mounting encapsulation structure using the temperature circulating test device |
| US9990454B2 (en) | 2016-06-03 | 2018-06-05 | International Business Machines Corporation | Early analysis and mitigation of self-heating in design flows |
Families Citing this family (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100367044C (en) * | 2004-12-17 | 2008-02-06 | 北京工业大学 | Electricity method for measuring thermal resistance front opacification for node type semiconductor luminous tube or laser device |
| CN101334370B (en) * | 2007-06-29 | 2010-09-22 | 英业达股份有限公司 | Method for simulating hot test chip thermal resistance value |
| CN102183546B (en) * | 2010-01-19 | 2014-12-24 | 财团法人工业技术研究院 | Detection device and method for package interface of light emitting diode |
| CN102297760B (en) * | 2010-06-25 | 2015-06-17 | 康佳集团股份有限公司 | Test method and design method of cooling fin of power device, and analog resistor |
| CN102116829B (en) * | 2010-12-21 | 2013-02-06 | 杭州远方光电信息股份有限公司 | Method and device for measuring thermal resistance of diode |
| TWI409476B (en) * | 2011-01-31 | 2013-09-21 | Chroma Ate Inc | Method of testing a light emitting diode die |
| CN102207534B (en) * | 2011-03-18 | 2013-04-17 | 华南师范大学 | Method and device for measuring thermal resistance of light emitting diode (LED) by pn junction |
| CN102693925B (en) * | 2011-03-25 | 2016-05-25 | 夏普株式会社 | The temperature characterisitic testing fixture of semiconductor light-emitting elements and temperature characterisitic inspection method |
| CN102680512A (en) * | 2012-05-10 | 2012-09-19 | 北京工业大学 | Method for measuring interface contact heat resistance |
| CN103823170B (en) * | 2012-11-16 | 2017-03-22 | 闽南师范大学 | Novel method for measuring thermal resistance of power-type LED integration module |
| CN103630820A (en) * | 2013-12-03 | 2014-03-12 | 黑龙江省计量科学研究院 | High-power LED heat resistance measuring device and method of measuring high-power LED heat resistance thereby |
| CN104407280A (en) * | 2014-12-01 | 2015-03-11 | 苏州立瓷电子技术有限公司 | Thermal resistance measuring method of LED lamp |
| CN107515043B (en) * | 2017-09-14 | 2020-06-12 | 合肥彩虹蓝光科技有限公司 | Method for testing light power of LED chip |
| TWI689724B (en) * | 2017-12-15 | 2020-04-01 | 財團法人工業技術研究院 | Chip temperature computation method and chip temperature computation device |
| EP3757559B1 (en) * | 2018-02-22 | 2024-05-15 | Osaka University | Substrate evaluation chip and substrate evaluation device |
| CN111983435B (en) * | 2020-08-26 | 2023-01-10 | 西安微电子技术研究所 | Test chip for hybrid integrated circuit life prediction test and application |
| CN114112113A (en) * | 2021-10-08 | 2022-03-01 | 中国电子科技集团公司第十三研究所 | Thermal resistance transfer standard component and thermal resistance measuring instrument calibration method |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06281693A (en) * | 1992-08-28 | 1994-10-07 | Fuji Electric Co Ltd | Measuring method for thermal resistance of semiconductor device |
| JPH10300811A (en) * | 1997-04-21 | 1998-11-13 | Canon Inc | Measuring method of led dc thermal resistance, and measuring device thereof |
| CN1395305A (en) * | 2002-07-05 | 2003-02-05 | 清华大学 | LED epitaxial wafer electroluminescent nondestructive detection method |
-
2003
- 2003-11-14 CN CNB200310112158XA patent/CN1330970C/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06281693A (en) * | 1992-08-28 | 1994-10-07 | Fuji Electric Co Ltd | Measuring method for thermal resistance of semiconductor device |
| JPH10300811A (en) * | 1997-04-21 | 1998-11-13 | Canon Inc | Measuring method of led dc thermal resistance, and measuring device thereof |
| CN1395305A (en) * | 2002-07-05 | 2003-02-05 | 清华大学 | LED epitaxial wafer electroluminescent nondestructive detection method |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101252099B (en) * | 2008-03-18 | 2012-03-28 | 日月光半导体制造股份有限公司 | Temperature circulating test device and heating chip upside-down mounting encapsulation structure using the temperature circulating test device |
| US9990454B2 (en) | 2016-06-03 | 2018-06-05 | International Business Machines Corporation | Early analysis and mitigation of self-heating in design flows |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1544954A (en) | 2004-11-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN1330970C (en) | Method for testing power type LED thermal resistance and special purpose chip thereof | |
| CN203502579U (en) | System used for calibrating light source capable of simulating solar radiation spectrum | |
| CN102072783B (en) | Method for testing junction temperature of LED | |
| CN103472088A (en) | Thermal resistance analysis method | |
| CN101266280A (en) | High power light-emitting diode heat resistance and junction temperature test system | |
| CN103344902B (en) | A kind of LED transient thermal resistance measuring system | |
| CN106546626B (en) | A kind of cell piece temperature correction solving photovoltaic module temperature coefficient | |
| CN204064410U (en) | A kind of electronic scales based on resistance strain gage | |
| CN101699235B (en) | Analysis and test system and test method for junction temperature of semiconductor lamp | |
| CN101881808A (en) | Organic electroluminescent diode service life tester | |
| CN103630851A (en) | Method and system for measuring entire thermal resistance of LED (light emitting diode) radiating module | |
| CN101299054B (en) | Measuring method of dye sensitization nano-film solar cell I-V characteristic and conversion efficiency characteristic | |
| CN102449494B (en) | Method for spatially determining the series resistance of a semiconductor structure | |
| CN103245694A (en) | Method for measuring thermal contact resistance between semiconductor device and contact material | |
| CN104748885A (en) | Method for measuring LED (Light Emitting Diode) junction temperature based on I-V feature curve | |
| CN109709470A (en) | A kind of multi-chip combined power amplifier crust thermo-resistance measurement method | |
| CN106644373A (en) | Simulation method for large-scale cooling tower wind tunnel test | |
| CN103823170B (en) | Novel method for measuring thermal resistance of power-type LED integration module | |
| CN204831599U (en) | LED lamps and lanterns junction temperature test system | |
| CN106990368B (en) | A kind of junction temperature measurement method of LED lamp | |
| CN100433282C (en) | Power type light-emitting diode device and its manufacturing method | |
| Bouřa | Characterization of a small amorphous photovoltaic panel and derivation of its SPICE model | |
| CN104464546A (en) | System for controlling LED display screen to lower LED junction temperature | |
| CN103605085A (en) | LED thermal characteristic test method based on structure function | |
| Levi et al. | Self-reference procedure to reduce uncertainty in module calibration |
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 | ||
| C56 | Change in the name or address of the patentee |
Owner name: FUSHAN CITY GUOXING PHOTOELECTRIC CO., LTD. Free format text: FORMER NAME OR ADDRESS: FUSHAN CITY GUOXING PHOTOELECTRICITY TECHNOLOGY CO.,LTD. |
|
| CP03 | Change of name, title or address |
Address after: 528000, No. 18, Huabao South Road, Chancheng District, Guangdong, Foshan Patentee after: Foshan Guoxing Photoelectric Co., Ltd. Address before: 528000 No. 24 Fenjiang North Road, Foshan, Guangdong Patentee before: Foshan Nationstar Optoelectronics Co., Ltd. |
|
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |