CN102221667B - Measuring device and method for diode chip - Google Patents

Abstract

The invention discloses a measuring device and a measuring method of a diode chip. The diode chip is arranged on the heat conduction element. The measuring device measures the instant start current of the diode chip and measures a first temperature of the heat conduction element corresponding to the instant start current. After the diode chip starts to operate, the measuring device adjusts the temperature of the heat conduction element to a second temperature so that the current of the diode chip is equal to the instant starting current. The measuring device calculates the attribute of the diode chip according to the real power of the diode chip and the temperature difference between the first temperature and the second temperature.

Description

Measuring device and method for diode chip

technical field

The present invention relates to a measuring device and a measuring method for a diode chip, and in particular to a measuring device and a measuring method for measuring a diode chip driven by alternating current.

Background technique

In recent years, the development of light-emitting diode (Light Emitting Diode, LED) semiconductor technology has greatly improved the luminous efficiency of chips due to the improvement of technology, and thus increased the applicability in various aspects, such as from projection pens to lighting applications, etc., a substantial increase the scope of application. In addition, LED also has the advantages of small size, long life, low pollution, and low cost. In terms of optical characteristics, it has the characteristics of good color saturation and dynamic color control. Therefore, LED-related technologies have become the most attention-grabbing technologies at present.

Generally speaking, the most widely known LED is that it is more energy-saving, more environmentally friendly, and smaller in size than traditional light sources. The emergence of AC-driven LEDs makes them more competitive in lighting systems, but the same We must face the problem of low conversion efficiency of electricity and light on the chip. At present, LED chips still convert most of the input electric energy into heat energy, and only a small part into light. Therefore, overheating is still the main issue in the development of LED technology. In the current situation where the luminous efficiency of LED chips is limited, most of the power is converted into heat, which also greatly increases the heat generation density. Overheating problem has become the bottleneck of technology development. The thermal resistance is defined as the temperature at the junction of the LED chip (Junction Temperature) minus the ambient temperature, and then divided by the value obtained by the input power. This thermal resistance value is the standard for judging the heat dissipation capability of the LED package. If the thermal resistance value is larger, it means that the heat dissipation capability is worse; on the contrary, if the thermal resistance value is smaller, the heat dissipation capability is better. Therefore, the thermal resistance value provides a criterion for judging.

In LED packaging, it is often necessary to limit the maximum thermal resistance of heat dissipation components, so the measurement of component thermal resistance is both important and representative. Among the parameters for calculating thermal resistance, the ambient temperature can be easily measured by using a thermocouple. For a heating element, its input power is also known and can be calculated. However, in a complete package, it is difficult to directly measure the junction temperature of the chip, so an indirect electrical measurement method is generally required to obtain the junction temperature of the chip. If this method can quickly and accurately measure the heat transfer characteristics of verification components and the influence of heat on optical characteristics, it will help to improve the heat transfer design and verification of LED chips to achieve effective heat dissipation.

In the same situation as AC-driven LEDs and DC-driven LEDs, the temperature of the chip junction cannot be directly measured, and must be converted by indirect electrical measurement methods. However, the thermal resistance measurement method of AC-driven LEDs is different from that of DC-driven LEDs. Because the input power of LED is AC, the input voltage and current are not constant values, but a sine cycle wave, so the measurement method will be different from that of DC drive LED. The establishment of thermal resistance measurement technology for AC-driven LED packages will help improve the heat dissipation design of AC-driven LED packages.

China Taiwan Patent No. 200925571 discloses a device for measuring LED characteristics and chip temperature. The measurement process mainly includes two steps. The first step is to measure the TSP (Temperature Sensitive Parameter) calibration curve of its bias value and temperature by using conduction form and input pulse form current. The second step is to measure the voltage value under actual operating conditions, and then use the TSP calibration curve to convert the temperature of the LED chip and the thermal resistance of the package. However, this device and method can only measure DC-driven LEDs. In addition, this previous proposal is only limited to the measurement of DC power LEDs, and does not integrate the measurement methods of the three characteristics of light, heat and electricity.

U.S. Patent Application No. US0815403043 discloses a method for measuring the junction temperature of an AC-driven LED. The measurement method is based on the measurement method of the thermal resistance of the LED of a DC power supply, except that the AC LED is measured by inputting an AC voltage. . The measurement process mainly has two stages. In the measurement step of the first stage, a start-up voltage is given to the LED, the temperature of different LED substrates is controlled, and the current of the LED and the temperature of the substrate are measured to obtain the characteristic curve of the LED. In the second stage of measurement, another small resistor is connected in series to actually operate the input of the rated AC voltage, and the dual-channel data acquisition module is used to simultaneously acquire the resistance value of the resistor and the voltage value of the AC power. Then find out the start-up voltage of the LED and the voltage value of the corresponding resistor from the voltage waveform to convert it into a current value. In addition, the current variation between the initial current value and the current value after reaching thermal equilibrium is obtained, so as to obtain the temperature variation according to the above-mentioned characteristic curve conversion. The above-mentioned temperature change plus the initial temperature value is the diode junction temperature.

Compared with the previous patents, although Taiwan Patent 200925571 has the function of quickly measuring the thermal resistance of LEDs, it is only limited to the measurement of DC power LEDs, and does not integrate the measurement methods of light, heat and electricity. . U.S. Patent Application No. US0815403043 Although the measurement method can measure AC power LEDs, the measurement procedure is complicated and requires two steps. In the second step, an additional resistor needs to be connected in series to measure, and the resistances are different in size. It will affect the measurement results, and because it is not easy to judge which resistance value to choose, there will be many variables and inconveniences in the measurement.

Contents of the invention

The invention provides a diode chip measuring device and its measuring method, which can accurately and quickly measure the electrical characteristics of the diode chip at a certain temperature.

The invention provides a method for measuring a diode chip. The measurement method described above includes placing the diode chip on a heat conducting element. Afterwards, a voltage is applied to the diode chip, and the instantaneous starting current of the diode chip is measured by the current measuring unit, and the temperature of the heat conduction element is measured as the first temperature by the temperature measuring element. After the voltage is applied to the diode chip, the temperature control module starts to control the temperature of the heat conduction element until the current of the diode chip measured by the current measuring unit is equal to the instantaneous starting current. After the temperature of the heat conduction element is controlled, if the current of the diode chip measured by the current measuring unit is equal to the instantaneous starting current, the temperature of the heat conduction element measured by the temperature measuring element is the second temperature.

The measuring method of the diode chip further includes:

calculating a real power of the diode chip when the voltage is applied;

subtracting the second temperature from the first temperature to obtain a temperature difference between the first temperature and the second temperature; and

Divide the temperature difference by the real power to obtain a thermal resistance of the diode chip.

The voltage is an AC voltage, and the measured current of the diode chip and the instantaneous start-up current are root mean square currents.

This voltage is a DC voltage.

The diode chip has at least one light emitting diode.

The invention provides a measuring device. The measurement device includes a heat conduction element, a voltage source, a current measurement unit, a temperature measurement element and a temperature control module. The heat conduction element is suitable for setting the above-mentioned diode chip. Said voltage source is suitable for applying voltage to said diode chip. The current measuring unit is suitable for measuring the current of the diode chip when the voltage source applies a voltage to the diode chip. The temperature measuring element is suitable for measuring the temperature of the heat conduction element. The temperature control module is adapted to control the temperature of the heat conduction element. When the voltage source starts to apply voltage to the diode chip, the current measurement unit measures the instantaneous starting current of the diode chip, and the temperature measurement element measures the temperature of the heat conduction element as a first temperature. After the above voltage is applied to the diode chip, the temperature control module starts to control the temperature of the heat conduction element to a second temperature, so that the current of the diode chip measured by the current measuring unit is equal to the above instantaneous starting current. The above-mentioned second temperature is not equal to the first temperature.

In an embodiment of the present invention, the above-mentioned measurement device calculates the real power of the diode chip when the above-mentioned voltage is applied, and subtracts the second temperature from the first temperature to obtain the temperature between the first temperature and the second temperature difference, and divide the above temperature difference by the above real power to obtain the thermal resistance value of the diode chip.

In an embodiment of the present invention, the above-mentioned voltage is an AC voltage, and the measured current of the diode chip and the instantaneous start-up current are root mean square currents.

In an embodiment of the present invention, the aforementioned voltage is a DC voltage.

In an embodiment of the present invention, the above-mentioned diode chip has at least one light emitting diode.

Based on the above, the diode chip measurement device and measurement method of the present invention can not only be used to measure the electrical characteristics of the diode chip driven by DC, but also can be used to measure the electrical characteristics of the diode chip driven by AC. In addition, the present invention can achieve very fast and high-precision control by using the conduction form of temperature control, and can quickly measure the optical, thermal and electrical characteristics of different chip junction temperatures.

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments, but not as a limitation of the present invention.

Description of drawings

1 is a schematic diagram of a measuring device according to an embodiment of the present invention;

Fig. 2 is a graph showing the relationship between the current and time flowing through the diode chip when the voltage source in Fig. 1 has not yet applied a voltage to the diode chip;

FIG. 3 is a diagram showing the relationship between the current and time flowing through the diode chip when the voltage source in FIG. 1 starts to apply voltage to the diode chip;

Fig. 4 is when the temperature control module in Fig. 1 controls the temperature of the heat conduction element, the relation diagram of the electric current of the diode chip and time;

FIG. 5 is a schematic diagram of a measuring device according to another embodiment of the present invention.

Among them, reference signs

100, 500: measuring device

101, 264: cooling module

102, 266: temperature control element

104: heat conduction element

105: insulating film

106: Diode chip

107: pin

108: Insulation cover

110: temperature controller

112: Power meter

114: Data reading card

116: fixed element

118: Temperature measuring element

258: Integrating sphere

Detailed ways

The embodiments of the present invention can achieve relatively complete, rapid and accurate results in the measurement of electrical and thermal characteristics of LEDs. In addition to measuring the electrical characteristics of diode chips driven by direct current, this method can also be used to measure the electrical characteristics of diode chips driven by alternating current. The following examples are given to describe the present invention, but the present invention is not limited to the examples given. In addition, the cited embodiments can also be properly combined with each other, without being limited to the content of a single embodiment.

Please refer to FIG. 1 , which is a schematic diagram of a measuring device 100 according to an embodiment of the present invention. Referring to FIG. 1 , in order to achieve temperature control, the temperature can be controlled by a temperature control module of the measurement device 100 . The aforementioned temperature control module may include a temperature control element 102, such as a heater, a thermoelectric cooler, and the like. The thermoelectric cooler can lower the temperature below the room temperature, so as to allow the measurement device 100 to perform measurements at a temperature lower than the room temperature. The heat source brought out by the temperature control element 102 can achieve stable heat dissipation through the thermal module 101, especially the heat energy of the thermoelectric cooler can be taken away when the thermoelectric cooler is in operation. Also, if a heater is used to increase the temperature, the heat dissipation module 101 is not required. In addition, the temperature control module also includes some control circuits, such as a temperature controller 110, to achieve the effect of temperature control. The temperature controller 110 may be a proportional-integral-derivative (PID) controller, a shutdown reactor cooling (SRC) controller, and other controllers.

The present invention further proposes a thermal conductive type measurement method to heat or cool the diode chip to be measured to reach the desired temperature. For example, it is connected to the temperature control element 102 through a heat conduction element 104 . In this way, the temperature of the heat conduction element 104 can quickly reach equilibrium with the temperature of the temperature control element 102 to obtain a desired temperature. The heat conduction element 104 is, for example, a metallic structural layer with a high thermal conductivity, for example a structural layer of copper, bronze, aluminum or the like. In an embodiment of the present invention, the surface of the heat conduction element 104 is coated with an insulating film 105 with high thermal conductivity. The material of the insulating film 105 is, for example, aluminum oxide, diamond-like carbon (DLC) film, and the like. The purpose of the insulating film 105 is to make use of its electrical insulation property to prevent the current of the diode chip 106 from partially leaking from the heat conduction element 104 during testing, thereby affecting the measurement accuracy. In addition, the measuring device 100 may include a heat insulating cover 108 disposed on the heat conducting element 105 to form a heat insulating space. The heat insulation cover 108 can be made by combining some heat insulation cotton and bakelite, for example.

In this embodiment, the diode chip 106 to be tested includes at least one light emitting diode, and the diode chip 106 is driven by alternating current. However, the present invention is not limited thereto. For example, in one embodiment of the present invention, the diode chip 106 to be tested does not include light-emitting diodes, but only has generally non-light-emitting diodes. For another example, in another embodiment of the present invention, the diode chip 106 is driven by direct current. In addition, the diode chip 106 to be tested can be adhered to the heat conduction element 104 by, for example, heat conduction paste, and is in the heat insulation space in the heat insulation cover 108 to obtain a better stable temperature. It is worth noting, however, that the insulating cover 108 is not an absolutely necessary element to the present invention. In addition, in an embodiment of the present invention, the measuring device 100 includes two fixing elements 116, which are respectively in contact with the two pins 107 of the diode chip 106, so as to fix the diode chip 106 on the heat conduction element 104, and make the quantity The tester can quickly replace the diode chip 106. In addition, in order to prevent the fixing element 116 from absorbing light from affecting the thermal measurement results of the diode chip 106 , in other embodiments of the present invention, the fixing element 116 can be made of white material, or the fixing element 116 can be coated with barium sulfate. Due to the structural design of the fixing element 116 that can provide the power supply of the diode chip 106 , there is no need to solder wires to connect the voltage source 112 and the two pins 107 of the diode chip 106 .

The above-mentioned temperature control module further includes a temperature measuring element 118 disposed at the junction of the substrate of the diode chip 106 and the heat conduction element 104 and placed under the diode chip 106 for detecting the temperature of the heat conduction element 104 . Basically, because the heat conduction element 104 and the insulating film 105 have extremely high thermal conductivity, the temperature measured by the temperature measuring element 118 will not only be equal to the temperature of the heat conduction element 104, but also equal to the substrate temperature of the diode chip 106. . The temperature measuring element 118 can be a thermocouple, a thermistor, or a resistance temperature detector (RTD).

The measurement device 100 also has a voltage source 112 suitable for applying a voltage to the diode chip 106 . In an embodiment of the present invention, the voltage source 112 can be a source meter, which can not only provide voltage to the diode chip 106, but also measure its output current at the same time. In another embodiment of the present invention, the measuring unit in the power meter 112 for measuring the current of the diode chip 106 can be separated from the power meter 112 to obtain a more accurate current value. The isolated current measurement unit is, for example, a data acquisition card (DAQ Card), which is electrically connected to the voltage source 112 and the diode chip 106 . In an embodiment of the present invention, the current resolution of the data acquisition card is less than 0.1 mA, so the measured current value has extremely high accuracy.

In the process of measuring the diode chip 106 , the aforementioned temperature control module is used to control the temperature of the substrate of the diode chip 106 and the temperature of the heat conduction element 104 to a stable temperature, for example, 25° C. At this time, the voltage source 112 has not yet applied a voltage to the diode chip 106 , and the junction temperature of the diode chip 106 will be the same as the temperature of the heat conduction element 104 due to thermal balance. Afterwards, the voltage source 112 applies a voltage to the diode chip 106 to make the diode chip 106 start to operate. During the initial period when the voltage source 112 starts to apply the voltage to the diode chip 106 , the current measurement unit 114 measures the instantaneous starting current of the diode chip 106 , and the temperature measurement element 118 measures the temperature of the heat conduction element 104 as a first temperature. In one embodiment of the present invention, if the diode chip 106 is driven by alternating current, the instantaneous starting current of the diode chip 106 measured by the current measuring unit 114 will be equal to the first positive half-wave of the current flowing through the diode chip 106 RMS value. In other words, the above-mentioned instantaneous starting current is the root mean square current. Therefore, the diode chip 106 is not affected by the thermal effect, so the instantaneous start-up current is the corresponding current value when the junction temperature of the diode chip 106 is the first temperature.

Please refer to FIG. 2 and FIG. 3 , wherein FIG. 2 is a graph showing the relationship between the current flowing through the diode chip 106 and time when the voltage source 112 has not yet applied a voltage to the diode chip 106 , and FIG. 3 is a graph showing the voltage source 112 starting to apply voltage to the diode chip 106. The relationship between the current flowing through the diode chip 106 and time is shown in FIG. Wherein, as shown in FIG. 2 , when the voltage source 112 is not applied to the diode chip 106 , the corresponding current value is zero. As shown in FIG. 3, when the current measurement unit 114 measures the instantaneous start-up current of the diode chip 106, it will calculate the diode chip current value according to the detected current value of the diode chip 106 during the period from _t1 to _t2 . 106 root mean square current, and the obtained root mean square current is the instantaneous starting current of the diode chip 106 . In addition, in an implementation of the present invention, if the diode chip 106 is driven by a DC voltage, the current waveform detected by the current measurement unit 114 will not be as shown in FIG. The current of the diode chip 106 is measured for a preset time interval after the source 112 starts to apply to the diode chip 106 to calculate the above-mentioned instantaneous start-up current. Wherein, the above-mentioned preset time interval is, for example, less than a millisecond level.

After the voltage is applied to the diode chip 106, the temperature of the diode chip 106 will gradually increase due to energy consumption. And because the temperature of the diode chip 106 rises, the current of the diode chip 106 also increases. To measure the characteristics of the diode chip 106, after the voltage is applied to the diode chip 106, the above-mentioned temperature control module starts to control the temperature of the heat conduction element 104 until the current of the diode chip 106 measured by the current measurement unit 114 is equal to the above-mentioned Instantaneously start the current. In addition, after the temperature of the heat conduction element 104 is controlled, if the current of the diode chip 106 measured by the current measurement unit 114 is equal to the above-mentioned instantaneous starting current, the temperature of the heat conduction element 104 at this time is measured by the temperature measurement element 118 The temperature is a second temperature. It should be noted that if the diode chip 106 is driven by an AC voltage, the current of the diode chip 106 measured by the current measuring unit 114 is also the RMS current.

Please refer to FIG. 4 . FIG. 4 is a diagram showing the relationship between the current of the diode chip 106 and time when the temperature control module controls the temperature of the heat conduction element 104 . In this implementation, the instantaneous start-up current of the diode chip 106 measured by the current measuring unit 114 is 27.05732 mA, and due to the thermal effect, the current of the diode chip 106 increases to about 28 mA. Afterwards, the temperature control module starts to lower the temperature of the heat conduction element 104 . Due to the decrease of the temperature of the heat conduction element 104 , the junction temperature of the diode chip 106 also decreases, and the current of the diode chip 106 also decreases accordingly. After the temperature of the heat conduction element 104 drops, if the current of the diode chip 106 measured by the current measurement unit 114 is equal to the above-mentioned instantaneous starting current, the temperature of the heat conduction element 104 measured by the temperature measurement element 118 at this time will That is, the above-mentioned second temperature. Taking FIG. 4 as an example, 500 seconds after the temperature control module starts to lower the temperature of the heat conduction element 104, the current of the diode chip 106 is equal to the instantaneous start-up current of the diode chip 106, and at this time the temperature measured by the temperature measuring element 118 is The temperature is the above-mentioned second temperature.

In one embodiment of the present invention, the current measurement unit 114 will calculate a real power (Real Power) of the diode chip 106 when a voltage is applied. If the real power of the diode chip 106 is represented by P _real , the real power P _real can be The following equation expresses:

${\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; real</span>}}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; T</span>}}{<span\; class="notranslate">\; \&Integral;</span>}}\frac{\mathrm{<span\; class="notranslate">\; V</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; I</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}\mathrm{<span\; class="notranslate">\; dt</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; apparently</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; PF</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

P _apparent = V _rms × I _rms (2)

Wherein, V(t) is the voltage value applied to the diode chip 106 at the time point t;

I(t) is the current value flowing through the diode chip 106 at time point t;

T is the current and voltage sampling cycle, and in one embodiment of the present invention, if the diode chip 106 is driven by an AC voltage, then T is the cycle of the AC voltage;

P _apparent is the apparent power of the diode chip 106;

V _rms is the root mean square voltage value of the diode chip 106;

I _rms is the root mean square current value of the diode chip 106;

PF is the power factor (Power Factor) of the diode chip 106.

Afterwards, a calculation circuit (not shown) of the measurement device 100 or the above-mentioned current measurement unit 114 will subtract the above-mentioned second temperature from the above-mentioned first temperature to obtain the difference between the first temperature and the second temperature. Temperature difference. For example, if the above-mentioned first temperature is T _J , the above-mentioned second temperature is T _C , and the above-mentioned temperature difference is ΔT, then:

ΔT＝T _J -T _C (3)

Afterwards, the calculation circuit or the current measurement unit 114 divides the temperature difference ΔT by the real power P _real to obtain a thermal resistance value of the diode chip 106 . Assuming that the thermal resistance of the diode chip 106 is equal to R _JC , then:

${\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; JC</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; \&Delta;T</span>}}{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; real</span>}}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; J</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}}}{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; real</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

FIG. 5 is a schematic diagram of a measuring device 500 according to another embodiment of the present invention. Referring to Fig. 5, the basic structure of the present embodiment is still similar to that of Fig. 1, but the heat insulating cover 108 can be changed to be assembled with the integrating sphere 258 and the heat conduction element 104, such as utilizing a chip fixing structure to fix the diode chip, which also Light leakage from the integrating sphere 258 can be prevented. The temperature control unit below the heat conduction element 104 includes, for example, the temperature control element 102 and the heat dissipation module 101 . In this way, the heat conduction element 104 can quickly reach the same temperature as the temperature control element 102 . In addition, the heat dissipation module 101 operates together with the temperature control element 102 to achieve temperature change control. In addition, the current of the diode chip can be provided by the power meter 112 , for example. The power meter 112 reads out the voltage value of the diode at the same time. In addition, a data reading card 114 can also be added to read a more accurate voltage value. In addition, besides controlling the temperature of the temperature control element 102 , the temperature controller 110 can also simultaneously control another temperature control element 266 to control the temperature of the integrating sphere 258 . The temperature control element 266 also operates in conjunction with the heat dissipation module 264 .

This embodiment can quickly install the diode chip and provide power without soldering the lead-out wires. Then the integrating sphere is designed as a heatable sphere to control the operating temperature of the heat conduction element and the ambient temperature, and then obtain the relationship between the optical characteristics and the ambient temperature (or the operating temperature of the heat conduction element).

The function of the integrating sphere is, for example, to scatter the light emitted by the light-emitting diode chip and integrate and add up its optical properties, which allows the present invention to simultaneously measure the optical properties and thermal properties. For example, when the input is the actual input current, the optical characteristics are measured; when the input is a small current, the chip temperature and thermal resistance are measured. The integrating sphere can be designed to have the function of a thermostat, so that the device can control the ambient temperature to observe the relationship between the optical characteristics of the light-emitting diode and the ambient temperature.

Certainly, the present invention also can have other multiple embodiments, without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and deformations according to the present invention, but these corresponding Changes and deformations should belong to the scope of protection of the appended claims of the present invention.

Claims (10)

1. the method for measurement of a diode chip for backlight unit, is characterized in that, comprising:

This diode chip for backlight unit is arranged on a heat-conduction component;

One voltage is applied to this diode chip for backlight unit, and by the starting current in a flash of this diode chip for backlight unit of current measurement unit measuring, and is one first temperature by the temperature that a measuring temp element measures this heat-conduction component;

After this voltage was applied to this diode chip for backlight unit, beginning was controlled the temperature of this heat-conduction component, until the electric current of this current measurement this diode chip for backlight unit that the unit measures equals this instant starting currents by a temperature control modules; And

After the temperature of controlling this heat-conduction component, if the electric current of this current measurement this diode chip for backlight unit that the unit measures equals this instant starting currents, the temperature that measures this heat-conduction component by this measuring temp element is one second temperature.

2. the method for measurement of diode chip for backlight unit according to claim 1, is characterized in that, more comprises:

Calculate the real power of this diode chip for backlight unit when applying this voltage;

This first temperature is deducted this second temperature, in the hope of the temperature difference between this first temperature and this second temperature; And

With this temperature difference divided by this real power, in the hope of a thermal resistance value of this diode chip for backlight unit.

3. the method for measurement of diode chip for backlight unit according to claim 1, is characterized in that, this voltage is alternating voltage, and the electric current of this diode chip for backlight unit that is measured and this instant starting currents are rms current.

4. the method for measurement of diode chip for backlight unit according to claim 1, is characterized in that, this voltage is DC voltage.

5. the method for measurement of diode chip for backlight unit according to claim 1, is characterized in that, this diode chip for backlight unit has at least one light emitting diode.

6. the measuring equipment of a diode chip for backlight unit, is characterized in that, comprising:

One heat-conduction component is used for arranging this diode chip for backlight unit;

One voltage source is used for a voltage is applied to this diode chip for backlight unit;

One current measurement unit is used for measuring the electric current of this diode chip for backlight unit when this voltage source applies this voltage at this diode chip for backlight unit;

One measuring temp element is for the temperature that measures this heat-conduction component; And

One temperature control modules is for the temperature of controlling this heat-conduction component;

Wherein when this voltage source begins to apply this voltage at this diode chip for backlight unit, the starting current in a flash of this this diode chip for backlight unit of current measurement unit measuring, and the temperature that this measuring temp element measures this heat-conduction component is one first temperature;

Wherein after this voltage is applied to this diode chip for backlight unit, this temperature control modules begins the temperature of this heat-conduction component is controlled to one second temperature, so that the electric current of this current measurement this diode chip for backlight unit that the unit measures equals this instant starting currents, and this second temperature is not equal to this first temperature.

7. the measuring equipment of diode chip for backlight unit according to claim 6, it is characterized in that, this current measurement unit calculates the real power of this diode chip for backlight unit when applying this voltage, this first temperature is deducted this second temperature in the hope of the temperature difference between this first temperature and this second temperature, and with this temperature difference divided by the thermal resistance value of this real power in the hope of this diode chip for backlight unit.

8. the method for measurement of diode chip for backlight unit according to claim 6, is characterized in that, this voltage is alternating voltage, and the electric current of this diode chip for backlight unit that is measured and this instant starting currents are rms current.

9. the method for measurement of diode chip for backlight unit according to claim 6, is characterized in that, this voltage is DC voltage.

10. the method for measurement of diode chip for backlight unit according to claim 6, is characterized in that, this diode chip for backlight unit has at least one light emitting diode.

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