TWI393896B - The light emitting diode wafer temperature measurement system and measurement method - Google Patents

The light emitting diode wafer temperature measurement system and measurement method Download PDF

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Publication number
TWI393896B
TWI393896B TW98137866A TW98137866A TWI393896B TW I393896 B TWI393896 B TW I393896B TW 98137866 A TW98137866 A TW 98137866A TW 98137866 A TW98137866 A TW 98137866A TW I393896 B TWI393896 B TW I393896B
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light
emitting diode
temperature
measuring
voltage
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TW98137866A
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TW201116835A (en
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Univ Nat Formosa
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Wafer temperature measuring system and measuring method for light emitting diode
The invention relates to the measurement of a light-emitting diode (LED), in particular to a wafer temperature measuring system and a measuring method for a light-emitting diode.
Temperature is a key factor affecting the luminous efficiency and service life of light-emitting diodes. When a light-emitting diode is affected by current power, the junction temperature of the light-emitting diode will also increase, and the long-term or continuously increasing high-temperature effect will change the semiconductor junction characteristics of the material, so that the light-emitting diode In the case of a polar body, a module component with a heat dissipation function is required to prevent the high temperature effect from affecting the component quality; however, for a light emitting diode having high power operation characteristics, the diode is connected under the action of a long time and a high current. The surface temperature will increase rapidly, and the speed of accumulated thermal energy is often less than the heat dissipation speed of the heat dissipating component, so that the general high-power light-emitting diode often changes the material properties inside the component due to the influence of high temperature, resulting in a decrease in luminous efficiency and a decay in service life. . Therefore, regardless of the operating conditions of low power or high power, the temperature of a light-emitting diode after being driven to emit light is an important basis for judging the performance of the light-emitting diode.
The "LED Thermal Resistance Measurement Standard Draft" drafted by the "LED Lighting Standard and Quality R&D Alliance" proposes a method for measuring the junction temperature of a light-emitting diode, which is first applied to a light-emitting diode to be tested. A measurement current that does not cause self-heating, the recommended range is between 100μA and 5mA; then the forward voltage of the light-emitting diode is measured as an initial forward voltage V F0 ; and then a heating current Substituting the measuring current to drive the light emitting diode, after the thermal stable state is reached, the measuring current is quickly replaced by the measuring current to drive the light emitting diode, and the corresponding forward voltage is measured, a working forward voltage V FSS ; since the temperature of the light emitting diode is linearly related to the forward voltage thereof under a fixed current driving, the light emitting diode has a coefficient K of a forward voltage and a temperature, Finally, the coefficient K, the initial junction temperature T J0 of the light-emitting diode, and the measured forward voltages V F0 , V FSS are substituted into the following three equations to calculate that after being driven by the heating current , Junction temperature of the light emitting diode T J:
ΔV F =|V F0 -V FSS |;
ΔT J = K × ΔV F ;
T J = T J0 + ΔT J .
In the foregoing method for measuring the junction temperature of the light-emitting diode, the method for determining the coefficient K is to first place the light-emitting diode in a temperature control box, and control the initial temperature T i to be stabilized at a near-room temperature state. For example, at 25 ° C, and applying the light-emitting diode does not cause the self-heating measurement current, and then measuring the forward voltage of the light-emitting diode, which is a room temperature voltage value V Fi ; The temperature in the control box is increased to a typical high temperature T h . After the thermal stability state is reached, the forward voltage of the light emitting diode is measured as a high temperature voltage value V Fh ; finally, the aforementioned voltage value and temperature are substituted into the following A calculation formula can be used to obtain the coefficient K:
However, the above-mentioned method for measuring the junction temperature of the light-emitting diode has the main disadvantage that there is no specific measurement system for actually performing the measurement method; another disadvantage is that the recommended current system is recommended. Between 100μA and 5mA, meaning that the measured current is within 50 times of the range recommended by the method, and the difference between different normal luminous power operations, the measuring current applicable to different LEDs It should be different. If an inappropriate measurement current is selected, for example, if the supplied current is insufficient for the driving power and not within the normal operating characteristic curve of the actual light-emitting diode, the measured voltage may be unstable. Therefore, the coefficient K obtained is affected, which in turn affects the accuracy of calculating the temperature of the LED.
In other words, the method for measuring the junction temperature of the light-emitting diode has the disadvantages and needs to be improved.
In view of the above-mentioned deficiencies, the main object of the present invention is to provide a wafer temperature measuring system and a measuring method for a light-emitting diode, which can specifically, simply and accurately measure the driving of a light-emitting diode. The wafer temperature of the light-emitting diode after normal light emission.
In order to achieve the above object, a wafer temperature measuring system for a light-emitting diode according to the technical idea of the present invention includes a power supply device for supplying a current to a light-emitting diode to be tested; a temperature control device for placing the light emitting diode and providing an adjustable ambient temperature to the light emitting diode; a test device comprising a driving unit and a switching circuit for providing the light emitting device The switching diode is configured to switch between the driving unit and the power supply device to electrically connect the light emitting diode to the light emitting diode; and a processing device And the power supply device, the temperature control device, and the test device are electrically connected, and the current supplied by the power supply device, the temperature provided by the temperature control device, and the switching circuit of the test device are controlled by the program Switching between the unit and the power supply device, the processing device is further configured to measure the forward voltage of the light emitting diode, and the program converts the forward voltage The wafer temperature of the light emitting diode. With the above measurement system, the forward voltage of a light-emitting diode can be specifically measured, and the wafer temperature of the light-emitting diode can be known. In the above-mentioned wafer temperature measuring system of the LED, the processing device may include a measuring unit and a processing unit, the measuring unit is electrically connected to the LED, and the LED may be used to measure the LED. The processing unit is electrically connected to the power supply device, the temperature control device, and the test device, and controls the devices.
In the above-mentioned wafer temperature measuring system of the light-emitting diode, the processing device further has a human-machine interface, which can be used to record the value of the forward voltage of the light-emitting diode corresponding to the signal received by the processing device, and record the The temperature control device provides the ambient temperature of the light-emitting diode, and can display the relationship between the two at any time to monitor the measurement process; thereby, the complicated and lengthy measurement process can utilize the record of the human-machine interface Features are easier to accomplish.
According to the technical idea of the present invention, a method for measuring a wafer temperature of a light-emitting diode first finds an optimum current of one of the light-emitting diodes to be tested; and then supplies the light-emitting diode to the light-emitting diode. In the case of the optimal current measurement, the wafer temperature of the light-emitting diode is changed, and the forward voltage of the light-emitting diode is measured to obtain the relationship between the forward voltage of the light-emitting diode and the wafer temperature. Finally, the forward voltage of the light emitting diode can be measured under the condition that the light emitting diode is switched to the optimal measuring current supplied to the light emitting diode under normal driving power conditions, and Using this relationship characteristic, the wafer temperature change caused by the light-emitting diode under normal driving power is known.
In the method for measuring the temperature of the above-mentioned light-emitting diode, the procedure for finding the optimum current of the light-emitting diode can be first according to the power of the light-emitting diode, in a range of current range, etc. Setting a plurality of measurement currents at intervals; then, continuously supplying the measurement currents to the light-emitting diodes, and respectively measuring the forward voltages of the light-emitting diodes corresponding to the respective measurement currents; In the measured currents, the difference between the forward voltages of the light-emitting diodes corresponding to the two adjacent currents is a voltage difference; finally, the voltage difference may be measured in the measured currents. If the value is less than a standard value, the minimum current is determined as the optimum current of the light-emitting diode.
Detailed construction, features, assembly or use of the wafer temperature measuring system and measuring method of the light-emitting diode provided by the present invention will be described in the detailed description of the subsequent embodiments. However, it should be understood by those of ordinary skill in the art that the present invention is not limited by the scope of the invention.
The technical content and features of the present invention will be described in detail below with reference to the accompanying drawings, wherein: FIG. 1 is a wafer temperature of a light-emitting diode according to a preferred embodiment of the present invention. A schematic diagram of a test device for a wafer temperature measurement system of a light-emitting diode according to a preferred embodiment of the present invention, showing a state in which it is in a first position; Similar to the second figure, the test device of the wafer temperature measuring system of the light emitting diode provided by the preferred embodiment of the present invention is in the second position; the fourth figure is a preferred embodiment of the present invention. A schematic diagram of a first human interface of a wafer temperature measuring system of a light emitting diode provided; a fifth figure is a second person of a wafer temperature measuring system for a light emitting diode according to a preferred embodiment of the present invention FIG. 6 is a block diagram of a first step to a second step of a method for measuring a temperature of a light-emitting diode according to a preferred embodiment of the present invention; and a seventh diagram of the present invention a better The third step of the block diagram of a method of measuring a temperature of a wafer of light emitting diodes provided in the embodiment.
Referring to the first to third embodiments, a wafer temperature measuring system 10 for a light emitting diode according to a preferred embodiment of the present invention includes a power supply device 20, a temperature control device 30, and a measuring unit 40. , a test device 50, and a processing unit 60.
The power supply device 20 is a device capable of supplying a current of less than 1 mA, and is electrically connected to one of the light-emitting diodes 70 to be tested for providing a stable direct current to the light-emitting diode 70.
The temperature control device 30 includes an oven 32 and a temperature controller 34, the temperature controller 34 can control the temperature inside the oven 32, and the accuracy thereof can be less than 1 ° C; the light-emitting diode 70 is Placed inside the incubator 32, the temperature control device 30 can provide a stable and adjustable ambient temperature for the illuminating diode 70.
The measuring unit 40 is a device for measuring voltage, such as an oscilloscope. The measuring unit 40 is electrically connected to the LEDs 70 for measuring the forward voltage of the LEDs 70. And output the corresponding signal.
The test device 50 includes a driving unit 52 and two switching circuits 54. The driving unit 52 can supply power to the LEDs 70 for normal illumination, and the switching circuits 54 can be as shown in the second figure. The first position and the second position as shown in the third figure are switched, so that the power supply device 20 is electrically connected to the light-emitting diode 70 and provided to the light-emitting diode 70. The current I M is measured, or the driving unit 52 is electrically connected to the LEDs 70 and supplied to the LEDs 70 for a driving current I H .
Referring to the drawings, the processing unit 60 includes a first human interface 62 as shown in the fourth figure, and a second human interface 64 as shown in the fifth figure, and the processing unit 60 utilizes The communication transmission bus of the GPIB interface is electrically connected to the power supply device 20, and utilizes a communication transmission protocol such as an RS-232 interface, a thermostat 34 of the temperature control device 30, the measurement unit 40, and the test device. The driving unit 52 of the 50 is electrically connected to the switching circuit 54. The processing unit 60 can control the current supplied by the power supply device 20 by the human-machine interfaces 52 and 54 developed by a development program such as LabVIEW. The temperature control device The temperature inside the incubator 32 of the 30, and the driving unit 52 of the testing device 50 and the switching circuit 54; further, the processing unit 60 can further receive the output of the measuring unit 40 corresponding to the illuminating diode 70 The signal of the voltage, and the signal is converted by the program to the temperature of the wafer of the light-emitting diode.
It is to be noted that, in the measurement system 10 provided by the present invention, the processing unit 60 is mainly used to perform the control and calculation functions as described above, and is not limited to a single computer as shown in the first embodiment of the present embodiment. The processing device; moreover, the measuring unit 40 and the processing unit 60 of the embodiment may be replaced by a processing device having a control, an operation, and a measuring function.
With the above-mentioned measuring system 10, the LED can be electrically switched to the power supply device 20 by the switching circuit 54 when the driving unit 52 is driven by the normal lighting power. For measuring the temperature of the wafer of the LED, please refer to the sixth and seventh figures. The measurement method has three steps: the first step is to find the optimum current of the LED 70.
First, according to the power of the light-emitting diode 70, in a range of 0.1 mA to 5 mA, a range of current ranges is selected, and a plurality of measurement currents are equally spaced in the interval; and then, the temperature is utilized. The ambient temperature of the light-emitting diode 70 provided by the control device 30 to the inside of the incubator 32 is a first initial temperature T i , which is usually set to be close to room temperature of 25 to 30 ° C, because the incubator The internal temperature of the light-emitting diode 70 can be regarded as the first initial temperature T i ; and the electrical connection to the light-emitting diode 70 The power supply device 20 continuously supplies the measured current to the light-emitting diode 70, and measures the forward voltage of the light-emitting diode 70 by using the measuring unit 40, and then calculates the corresponding current of the measuring current. The difference between the forward voltages is a voltage difference; according to the characteristic curve of the current of the light-emitting diodes to the voltage, the larger the measuring current is, the smaller the voltage difference is, that is, the measured value is The more stable the voltage is; however, the larger the current is measured, the more The light-emitting diode 70 is operated at a high power characteristic, and the LED element 70 is more likely to generate self-heating; therefore, among the measured currents, the voltage difference is less than a standard value, the smallest of which The current is determined as the optimum measurement current I M of the light-emitting diode.
The measuring unit 40 outputs a signal corresponding to the measured voltage to the processing unit 60, and the internal voltage program calculates the voltage difference and the optimal current of the LED 70. The determination is performed, and the value of the optimal measurement current I M is displayed on the measurement current column 621 of the first human interface 62.
The second step is to obtain the relationship between the forward voltage of the light-emitting diode 70 and the wafer temperature in the case where the optimum current is supplied to the light-emitting diode 70.
After learning the optimal measurement current I M of the light-emitting diode 70 to be tested, the first initial temperature T i is also supplied to the light-emitting diode 70 by the temperature control device 30, and is regarded as At the same time, the temperature of the light-emitting diode 70 is controlled; at the same time, the processing unit 60 controls the power supply device 20 to supply the optimum current I M to the light-emitting diode 70, and controls the amount of the measuring unit 40 to start. Measuring the forward voltage of the light-emitting diode 70, and displaying the measured voltage value in a voltage display field 622 of the first human-machine interface 62; then, the temperature control device 30 is controlled by the processing unit 60. The temperature supplied to the light-emitting diode 70 is gradually increased to a typical high temperature T h , which is usually set to 100 to 110 ° C; the internal temperature of the incubator 32 is raised from the first initial temperature T i to the typical During the high temperature T h , a plurality of measured temperatures between the first initial temperature T i and the typical high temperature T h are set, and the oven 32 is heated until the internal temperature reaches each of the measured temperatures. Suspending the internal temperature of the oven 32 to maintain the temperature at the measurement temperature. After the time of the wafer temperature of the light-emitting diode 70 is equal to the measured temperature, the forward voltage of the light-emitting diode 70 is measured, and then the oven 32 is further heated, so that the light-emitting diode is The wafer temperature of the polar body 70 reaches the typical high temperature T h , and each of the measured temperature and the forward voltage value measured under the measured temperature are recorded on the first human interface 62 The data in the data table 624 and the one of the monitors 625 on the human interface 62 show the relationship between the forward voltage of the LEDs 70 and the temperature of the wafer; the curve displayed by the monitor 625 can be monitored at any time. The forward voltage of the light-emitting diode 70 changes, and since the forward voltage of the light-emitting diode is linear with the temperature of the wafer, the data recorded by the data table 624 can be used to know when the light-emitting diode is used. When the wafer temperature of 70 is the first initial temperature T i , the forward voltage is a first initial voltage value V i , and the forward voltage of the light-emitting diode 70 when the wafer temperature is a typical high temperature T h system is a high-temperature voltage V h, and then by the processing unit 60 Section of the program, the amount of the measured data is substituted into the following first equation, calculated along the light emitting diode 70 of the voltage versus k wafer temperature coefficient of:
In order to make the measurement more accurate, the curve of the forward voltage of the light-emitting diode and the temperature of the wafer can be statistically analyzed by the change of the forward voltage corresponding to the measured temperature, and the regression curve is statistically analyzed. The above k value corresponding to the linear condition is obtained.
The third step can measure the wafer temperature of the light-emitting diode 70 after the light-emitting diode 70 is driven by the driving unit 52 to emit light normally.
First, in the case that the ambient temperature is a second initial temperature T 0 , the LED 6 is disposed in the testing device 50, and the switching circuit 54 is first placed in the first position, that is, the LED The power supply device 20 is electrically connected to the power supply device 20; the power supply device 20 is controlled by the processing unit 60 to provide the optimal measurement current I M obtained in the first step to the light emitting diode 70, and the The measuring unit 40 starts measuring the forward voltage of the LEDs 70, and displays them in a voltage display column 642 of the second human interface 64 and a data table 643 recorded in the second human interface 64. Next, the processing unit 60 controls the switching circuit 54 to be activated to switch to the second position, so that the driving unit 52 is electrically connected to the light emitting diode 70 instead of the power supply device 20, the processing unit 60, and the power required by the driving unit 52 for the normal operation of the light-emitting diode 70 is controlled; thus, the temperature of the wafer of the light-emitting diode 70 is gradually increased, and thus the light-emitting diode 70 is The forward voltage will change linearly with it. The processing unit 60 controls the switching circuit 54 to quickly return to the first position after the time setting bar 645 of the man-machine interface 54 is set to be sufficient for the LED to be thermally stable. The light emitting diode 70 is electrically connected to the power supply device 20.
In the foregoing process, the data table 643 records the value measured by the measuring unit 40, and includes a forward voltage of the light emitting diode 70 when the initial ambient temperature is the second initial temperature T 0 . a second initial voltage value V F0 , and finally the switching circuit 54 returns to the first position, the forward voltage of the light emitting diode 70 is an operating voltage value V FS ; finally, by the processing unit 60 The program uses the following second equation:
T S =T 0 +k×(V FS -V F0 );
Substituting the second initial temperature T 0 , the second initial voltage value V F0 , the operating voltage value V FS , and the coefficient k into the second equation, calculating that the light emitting diode 70 is driven by the driving unit 52 The wafer temperature T S of the light-emitting diode 70 after normal light emission.
The wafer temperature measuring system 10 of the light emitting diode and the measuring method thereof can develop a plurality of human-machine interfaces by using a development program having powerful data acquisition and monitoring functions such as LabVIEW, and the measurement All the instrument hardware of the system 10 communicates to assist in the complicated and lengthy measurement process; furthermore, by finding the best measurement current of the LED to be tested, the calculated wafer temperature can be further improved. accurate.
Finally, it is to be noted that the constituent elements disclosed in the foregoing embodiments are merely illustrative and are not intended to limit the scope of the present invention, and alternative or variations of other equivalent elements should also be the scope of the patent application of the present application. Covered.
10. . . LED temperature measuring system for light emitting diode
20. . . Power supply unit
30. . . Temperature control device
32. . . temperate box
34. . . thermostat
40. . . Measuring unit
50. . . Test device
52. . . Drive unit
54. . . Switching circuit
60. . . Processing unit
62. . . First human machine interface
621. . . Measuring current bar
622. . . Voltage display
624. . . data sheet
625. . . Monitoring chart
64. . . Second human interface
642. . . Voltage display
643. . . data sheet
545. . . Time setting bar
70. . . Light-emitting diode
The first figure is a schematic diagram of a wafer temperature measuring system for a light emitting diode according to a preferred embodiment of the present invention;
2 is a circuit diagram of a test device for a wafer temperature measurement system of a light-emitting diode according to a preferred embodiment of the present invention, showing a state in which it is in a first position;
The third figure is similar to the second figure, but shows that the test device of the wafer temperature measuring system of the light-emitting diode according to a preferred embodiment of the present invention is in the second position;
FIG. 4 is a schematic diagram of a first human-machine interface of a wafer temperature measuring system for a light-emitting diode according to a preferred embodiment of the present invention; FIG.
FIG. 5 is a schematic diagram showing a second human interface of a wafer temperature measuring system for a light emitting diode according to a preferred embodiment of the present invention; FIG.
FIG. 6 is a block diagram showing a first step to a second step of a method for measuring a temperature of a wafer of a light-emitting diode according to a preferred embodiment of the present invention;
FIG. 7 is a block diagram showing a third step of a method for measuring a wafer temperature of a light-emitting diode according to a preferred embodiment of the present invention.
10. . . LED temperature measuring system for light emitting diode
20. . . Power supply unit
30. . . Temperature control device
32. . . temperate box
34. . . thermostat
40. . . Measuring unit
60. . . Processing unit
70. . . Light-emitting diode

Claims (10)

  1. A wafer temperature measuring system for a light emitting diode includes: a power supply device for supplying a current to the light emitting diode; and a temperature control device having an incubator and a temperature controller, The thermostat is configured to place the LED, the thermostat is used to control the temperature inside the incubator; a test device includes a driving unit and a switching circuit for driving the illumination The switching circuit is configured to switch between the driving unit and the power supply device to electrically connect one of the light emitting diodes; and a processing device and the power supply The device, the temperature control device, and the test device are electrically connected, and the device controls the device to: a) control the current supplied by the power supply device; b) control the temperature controller of the temperature control device; c) controlling the switching between the switching circuit of the test device and the power supply device; the processing device is further configured to measure the forward voltage of the light emitting diode, and the program is used to forward the forward voltage A down converter wafer temperature of the light emitting diode.
  2. The wafer temperature measuring system of the light emitting diode according to the first aspect of the invention, wherein the processing device comprises a measuring unit and a processing unit, wherein the measuring unit is electrically connected to the light emitting diode, Measure The processing unit is electrically connected to the power supply device, the temperature control device, and the test device, and controls the devices.
  3. The wafer temperature measuring system of the light-emitting diode according to claim 1, wherein the processing device further comprises a human-machine interface, which has a numerical value table for recording the temperature control device to provide the light-emitting diode The ambient temperature of the polar body and the value of the forward voltage of the LED that corresponds to the ambient temperature.
  4. The wafer temperature measuring system of the light-emitting diode according to claim 3, wherein the human-machine interface has a monitoring chart for displaying a relationship between an ambient temperature and a forward voltage in the numerical value table. For monitoring measurement process.
  5. A method for measuring a wafer temperature of a light-emitting diode comprises the steps of: a) finding an optimum current for measuring one of the light-emitting diodes to be tested; b) optimizing the light-emitting diode for the light-emitting diode In the case of measuring the current, changing the temperature of the wafer of the light-emitting diode and measuring the forward voltage of the light-emitting diode to obtain a curve of the forward voltage of the light-emitting diode and the temperature of the wafer, corresponding to The slope of the relationship curve has a relationship coefficient k; and c) changing the current of the LED to a driving current, and then switching the current of the LED to the optimal current, measuring the LED The forward voltage of the body, and using the relationship characteristic, the temperature of the wafer corresponding to the driving current of the light-emitting diode is known.
  6. The temperature measurement method of applying a light emitting diode chip in item 5 of the patent range, wherein step a) comprises the following procedure: a 1) in accordance with the power of the light emitting diode is within a range of the current interval, setting a plurality of equally spaced measuring current; a 2) is continuously supplied to the light-emitting diode such measuring currents, respectively, and measuring the light emitting diode corresponding to each of the measured currents a forward voltage; A 3 ) calculating, in the process of step a 2 ), the difference between the forward voltages of the light-emitting diodes corresponding to the two adjacent currents is a voltage difference; and a 4 ) measuring the currents Where the voltage difference is less than a standard value, wherein the minimum current is determined as the optimum measured current of the light emitting diode.
  7. The method for measuring a wafer temperature of a light-emitting diode according to claim 5, wherein the step b) comprises the following procedure: b 1 ) providing a stable ambient temperature to the light-emitting diode, which is a first The initial temperature T i , after the light-emitting diode reaches a thermal stable state, the wafer temperature is the first initial temperature T i ; b 2 ) is supplied to the light-emitting diode to optimize the current; b 3 Gradually increasing the ambient temperature of the light-emitting diode to a typical high temperature T h such that the wafer temperature of the light-emitting diode is gradually increased to the typical high temperature T h ; and b 4 ) from the first initial temperature T i to During the typical high temperature T h , the forward voltage of the light emitting diode and the ambient temperature are measured to obtain the relationship between the forward voltage of the light emitting diode and the wafer temperature.
  8. The method for measuring a wafer temperature of a light-emitting diode according to claim 7 is as follows: in step b), a coefficient k of a forward voltage of the light-emitting diode and a wafer temperature is obtained, and the ambient temperature is used. When the first initial temperature T i and the typical high temperature T h are measured, the forward voltage of the light emitting diode is measured, and a first initial voltage value V i and a high temperature voltage value V h are respectively obtained by The following first equation is obtained:
  9. The method for measuring the temperature of a light-emitting diode according to the fifth aspect of the invention is further for measuring a wafer temperature of the light-emitting diode after the light-emitting diode is normally illuminated by the driving current. Therefore, in step c), the light-emitting diode is normally illuminated, and after the temperature of the light-emitting diode wafer is raised, the optimum current is quickly supplied to the light-emitting diode, and then the amount is measured. Measure its forward voltage.
  10. The method for measuring the temperature of the light-emitting diode according to claim 9 of the patent application, before measuring step c, first measuring the ambient temperature of the light-emitting diode at the time, and is regarded as a second initial of the light-emitting diode Temperature T 0 , and simultaneously measuring the forward voltage of the light-emitting diode with the optimal measured current as a second initial voltage value V F0 , measuring the smoothness of the light-emitting diode in step c) After the voltage is an operating voltage value V FS , using the second initial temperature T 0 , the second initial voltage value V F0 , the operating voltage value V FS , and the coefficient k, by using the following second equation, The wafer temperature T S of the light-emitting diode is calculated after the light-emitting diode is driven to emit light normally: T S = T 0 + k × (V FS - V F0 ).
TW98137866A 2009-11-06 2009-11-06 The light emitting diode wafer temperature measurement system and measurement method TWI393896B (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040207424A1 (en) * 1998-08-27 2004-10-21 The Micromanipulator Company, Inc. High resolution analytical probe station
TW200506375A (en) * 2003-05-16 2005-02-16 Tokyo Electron Ltd Inspection apparatus
TWI286602B (en) * 2002-10-31 2007-09-11 Harald Philipp Charge transfer capacitive position sensor
TW200913298A (en) * 2007-09-13 2009-03-16 Asia Optical Co Inc Photo-sensing system and method capable of adjusting working voltage according to the variation of temperature
TWI312221B (en) * 2006-06-22 2009-07-11 Kao Golden Cit

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040207424A1 (en) * 1998-08-27 2004-10-21 The Micromanipulator Company, Inc. High resolution analytical probe station
TWI286602B (en) * 2002-10-31 2007-09-11 Harald Philipp Charge transfer capacitive position sensor
TW200506375A (en) * 2003-05-16 2005-02-16 Tokyo Electron Ltd Inspection apparatus
TWI312221B (en) * 2006-06-22 2009-07-11 Kao Golden Cit
TW200913298A (en) * 2007-09-13 2009-03-16 Asia Optical Co Inc Photo-sensing system and method capable of adjusting working voltage according to the variation of temperature

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