KR20120029155A - Device and method of measuring of light emitting diode - Google Patents

Abstract

PURPOSE: An efficiency measuring device of the LED(Light Emitting Diode) and a measuring method are provided to accurately and rapidly measure the efficiency of the LED because the light quantity efficiency is calculated by using heating characteristics of the LED without a rotation of equipments or usage of an auxiliary light source. CONSTITUTION: An efficiency measuring method(100) of the LED is as follows. The heat radiation quantity of the LED is measured. The light quantity efficiency is calculated by using the heat radiation quantity of the LED. A measuring process is simplified because the light quantity efficiency is calculated by simple calculating steps without repeating complex calculation steps.

Description

DEVICE AND METHOD OF MEASURING OF LIGHT EMITTING DIODE}

The present invention relates to a device and a method for measuring the efficiency of a light emitting diode, and more particularly, to a device and a method for measuring the efficiency of a light emitting diode that can be calculated simply and inexpensively.

Light Emitting Diode (LED) is an optical device using a semiconductor that emits light based on recombination of electrons and holes, and has excellent characteristics such as reaction speed, power consumption, and heat generation compared to conventional light sources. It is widely used in various types of light sources in the device.

When the light emitting diode is applied to various types of light sources, the most important measurement variable is lighting efficiency. Here, the lighting efficiency refers to an index for evaluating light output relative to electric energy, and the efficiency may be evaluated according to how efficiently the light emitting diode emits light compared to power consumption.

In general, the illumination efficiency of a light emitting diode can be calculated by measuring the total luminous flux. Total luminous flux refers to the total amount of luminous flux emitted from a light source, and conventionally known total luminous flux measurement methods include a measuring method using a side angle photometer or an integrating sphere.

As one of the conventional methods for measuring the total luminous flux, the measuring method using the angle measuring photometer is a method of measuring the total luminous flux by numerically integrating the luminous intensity or light intensity measured by the angle measuring photometer with respect to the solid angle. However, the measurement method using the angle measurement photometer has a problem that it is difficult to apply in the field because the measurement time is very long.

As another conventional method for measuring total luminous flux, a measuring method using an integrating sphere may be configured by using a hollow sphere-shaped integrating sphere. It is a method of measuring the luminous flux by the number of measurement times set by the spectroradiometer, calculating the average value and the sample standard deviation, and calculating the absorptance using the ratio, and calculating the total luminous flux value corrected by the absorptance. However, the measuring method using the integrating sphere has a problem that the measuring process is very complicated and cumbersome, as well as the rise of the price of the measuring device, and also takes a long time to measure.

Accordingly, recently, some measures have been proposed for a device and method for measuring efficiency of a light emitting diode which can simplify the measurement process, shorten the measurement time, and reduce the cost, but there is still insufficient development. It is required.

The present invention provides a device and method for measuring the efficiency of a light emitting diode which can simplify the measurement process and can shorten the measurement time.

In particular, the present invention provides a light emitting diode efficiency measuring apparatus and method that can calculate the light quantity efficiency by using the heat generating characteristics of the light emitting diode.

In addition, the present invention provides a device and method for measuring the efficiency of a light emitting diode that can simplify the structure of the measuring device and can reduce the cost.

According to a preferred embodiment of the present invention for achieving the above object of the present invention, the method of measuring the efficiency of the light emitting diode calculates the light quantity efficiency using the calorific value of the light emitting diode.

The power of the light emitting diode may be defined as light and heat. Therefore, if the amount of heat radiation emitted from the light emitting diode is known, the light quantity efficiency of the light emitting diode can be calculated through correlation with the input power applied to the light emitting diode. Conventionally, if the efficiency is calculated by directly measuring the light emitted from the light emitting diode, the measuring method and apparatus according to an aspect of the present invention can indirectly measure the lighting efficiency using heat emitted from the light emitting diode.

Specifically, the light quantity efficiency of the light emitting diode may be calculated by the following equation [1].

- - - 수학식[1]

---Equation [1]

Here, Q _LED of Equation [1] is the heat generation amount of the light emitting diode, and P _input is the input power (V * I) applied to the light emitting diode.

The calorific value Q _LED of the light emitting diode may be calculated in various ways depending on the required conditions and design specifications. For example, the calorific value Q _LED of the light emitting diode may be specified using a first heat transfer medium bonded to the light emitting diode and a first heat radiating medium bonded to the first heat transfer medium. When placed on the first bonding surface of the medium, and the heat transfer by the light emitting diode is kept uniform, it can be calculated by the following equation [2].

- - - 수학식[2]

---Equation [2]

는 발광다이오드에 접합되는 제1열전달매체의 제1접합면의 온도(T₁) 및 제1열방출매체에 접합되는 제1열전달매체의 제2접합면의 온도(T₂) 간의 온도차(T₁-T₂)이고, 상기 R은 제1열전달매체의 열저항 계수이다.Where equation [2]

Temperature difference between the temperature of the first bonding surface of the first heat transfer medium is joined to the light-emitting diode (T ₁₎ and a first temperature (T ₂₎ of the second joint surface of the first heat transfer medium is joined to the heat-emitting medium (T ₁ -T ₂ ), where R is the thermal resistance coefficient of the first heat transfer medium.

The thermal resistance coefficient R of the first heat transfer medium may be a predetermined constant, but a measurement variable may occur depending on the measurement environment and conditions. For example, measurement variables may occur due to the temperature, humidity, and air volume of the measurement site, and have a slightly different condition depending on the configuration of the measuring device. Therefore, it is necessary to correct these parameters at each measurement. In this case, the thermal resistance coefficient R of the first heat transfer medium may be calculated using a separate thermal resistance calculator under substantially the same conditions as the light emitting diodes. For example, the heat resistance calculation unit may include a heater, a second power supply unit supplying power to the heater, a second heat transfer medium bonded to the heater, a second heat radiating medium bonded to the second heat transfer medium, and a second heat transfer bonded to the heater. A second temperature sensor unit for measuring a temperature difference between the first bonding surface of the medium and the second bonding surface of the second heat transfer medium bonded to the second heat dissipating medium, and a correlation between the calorific value of the heater and the temperature difference between the respective bonding surfaces And a second calculation unit for calculating a thermal resistance coefficient (R) of the second heat transfer medium from the second calculation unit, wherein the second calculation unit calculates the thermal resistance coefficient (R) of the first heat transfer medium by the following equation [3]. Can be calculated.

- - - 수학식[3]

---Equation [3]

는 히터에 접합되는 제2열전달매체의 제1접합면의 온도(T_1') 및 제2열방출매체에 접합되는 제2열전달매체의 제2접합면의 온도(T_2') 간의 온도차(T_1'-T_2')이고, Q_heater는 미리 결정된 히터의 발열량이다.Where equation [3]

Is the temperature difference T between the temperature T _{1 ′} of the first bonding surface of the second heat transfer medium bonded to the heater and the temperature T _{2 ′} of the second bonding surface of the second heat transfer medium bonded to the second heat radiating medium. _{1 '-T 2')} and, Q _heater is a pre-determined heating value of the heater.

For reference, in the present invention, that the light emitting diode and the heater are provided under substantially the same conditions may mean that the light emitting diode and the heater are on the same heat transfer medium and the heat radiating medium, and the same temperature, humidity, Under conditions such as air volume, it may be understood that heat generated from the light emitting diodes and the heater is transferred to the measurement using another heat transfer medium and heat release medium having the same specification and material.

That is, each heat transfer medium and each heat release medium may be used in common for a light emitting diode or a heater under substantially the same conditions, and may be separately provided to the light emitting diode and the heater under the same conditions, respectively.

In addition, the calorific value specified by the temperature difference between the joining surfaces of the heat transfer medium may mean heat energy transferred mainly to the heat generating medium through the heat transfer medium, but in some cases, the peripheral system including the heat transfer medium. It can also be understood as a concept involving the thermal energy emitted from.

On the other hand, the upper portion of the heater is preferably covered with a conventional encapsulation layer such as epoxy, silicone resin, etc., which seals the upper portion of the light emitting diode to form the same condition as the light emitting diode. Therefore, most of the heat generated from the light emitting diode and the heater may be transferred to the first or second heat transfer medium bonded to the lower portion of the light emitting diode and the heater. It is also possible to calculate the illumination efficiency of a single light emitting diode, but in some cases a plurality of light emitting diodes (LED ARRAY) provided so that the plurality of light emitting diodes have a predetermined arrangement spaced apart from each other under substantially the same conditions. It is also possible to simultaneously measure the light quantity efficiency of the diode.

According to the efficiency measuring apparatus and method of the light emitting diode according to the present invention, the measurement process can be simplified, and the measurement time can be shortened.

In particular, according to the present invention, since the light quantity efficiency can be calculated using the heat generating characteristics of the light emitting diode, the efficiency of the light emitting diode can be measured more quickly and accurately.

In addition, according to the present invention, since it is possible to calculate the light quantity efficiency by simply using the heat generating characteristics of the light emitting diode, without using a separate auxiliary light source or rotating the equipment separately, the structure of the measuring apparatus can be simplified as well. It is suitable for mass production and can save cost.

In addition, according to the present invention, since the light quantity efficiency can be calculated by a relatively simple calculation step without having to repeatedly go through many complicated calculation steps, it is possible to simplify the process of measuring the efficiency of the light emitting diode and to reduce the measurement time. Can be.

1 is a view for explaining an efficiency measuring device and method of a light emitting diode according to the present invention.
2 is a view for explaining a heat resistance calculation unit as an efficiency measuring device of a light emitting diode according to the present invention.
3 and 4 illustrate an apparatus for measuring efficiency of a light emitting diode according to another exemplary embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not limited or limited by the embodiments. In describing the present invention, a detailed description of well-known functions or constructions may be omitted for clarity of the present invention.

1 is a view for explaining the efficiency measuring device and method of the light emitting diode according to the present invention, Figure 2 is a view for explaining the heat resistance calculation unit as an efficiency measuring device of the light emitting diode according to the present invention. 3 and 4 are diagrams illustrating an apparatus for measuring efficiency of a light emitting diode according to another exemplary embodiment of the present invention.

1 and 2, the efficiency measuring apparatus and method of the light emitting diode 100 according to the present invention, the amount of light of the light emitting diode 100 by using the calorific value of the light emitting diode (LED) 100 Configured to yield efficiency.

Hereinafter, the efficiency measuring device of the light emitting diode 100 according to the present invention, the first power supply 400 for supplying power to the light emitting diode 100, the first heat transfer medium 200 is bonded to the light emitting diode 100 ), A first bonding surface of the first heat radiating medium 300 bonded to the heat transfer medium 200, a first bonding surface of the first heat transfer medium 200 bonded to the light emitting diode 100, and a first heat radiating medium 300. The first temperature sensor unit 500 for measuring the temperature difference between the second bonding surface of the first heat transfer medium 200 bonded to the light source, and the calorific value of the light emitting diodes 100 and an input applied to the light emitting diodes 100. An example configured to include the first operation unit 600 that calculates the light quantity efficiency of the light emitting diode 100 from the correlation between power will be described.

Specifically, power of the light emitting diode 100 may be defined as light and heat. Therefore, when the amount of heat radiation emitted from the light emitting diodes 100 is known, the light quantity efficiency of the light emitting diodes 100 may be calculated through correlation with the input power applied to the light emitting diodes 100. The light quantity efficiency can be calculated by the following equation [1].

[Equation 1]

Here, the Q _LED of Equation [1] is a heat generation amount of the light emitting diode 100, and P _input is an input power V * I applied to the light emitting diode 100.

The amount of heat generated (Q _LED ) of the light emitting diodes 100 may be calculated in various ways according to the required conditions and design specifications. For example, the calorific value Q _LED of the light emitting diodes 100 may include a first heat transfer medium 200 bonded to the light emitting diodes 100 and a first heat radiating medium 300 bonded to the heat transfer medium 200. When the light emitting diodes 100 are positioned on the first bonding surface of the first heat transfer medium 200, and the heat transfer by the light emitting diodes 100 is maintained uniformly, It can be calculated by equation [2].

[Equation 2]

는 발광다이오드(100)에 접합되는 제1열전달매체(200)의 제1접합면의 온도(T₁) 및 제1열방출매체(300)에 접합되는 제1열전달매체(200)의 제2접합면의 온도(T₂) 간의 온도차(T₁-T₂)이고, 상기 R은 제1열전달매체(200)의 열저항 계수이다.Here, the equation [2]

Is the temperature T ₁ of the first bonding surface of the first heat transfer medium 200 bonded to the light emitting diodes 100 and the second bonding of the first heat transfer medium 200 bonded to the first heat emitting medium 300. It is a temperature difference T ₁ -T ₂ between the temperatures T ₂ of the surface, and R is a thermal resistance coefficient of the first heat transfer medium 200.

For reference, a first bonding surface of the first heat transfer medium 200 bonded to the light emitting diodes 100, and a second bonding surface of the first heat transfer medium 200 bonded to the first heat emitting medium 300. The temperature of may be measured using the first temperature sensors (510, 520). As the first temperature sensors 510 and 520, a thermocouple, a thermopile, or a resistance temperature detector (RTD) may be used, and other sensors may be used according to required conditions and measurement environments. May be used.

In addition, a general metal having excellent thermal conductivity may be used as the heat transfer medium 200, and the present invention is not limited or limited by the type and characteristics of the heat transfer medium 200. In addition, a conventional heat sink may be used as the heat dissipation medium 300, and the present invention is not limited or limited by the type and characteristics of the heat sink.

The thermal resistance coefficient R of the first heat transfer medium 200 may be a predetermined constant. Knowing the thermal resistance coefficient (R) of the first heat transfer medium 200, the first calculation unit 600 may calculate the heat generation amount (Q _LED ) of the light emitting diode 100 through the above equation [2]. Based on this, the light quantity efficiency of the light emitting diode 100 can be calculated through the above equation [1].

Meanwhile, measurement variables may occur depending on the measurement environment and conditions. For example, measurement variables may occur due to temperature, humidity, and air volume. In this case, the thermal resistance coefficient R of the first heat transfer medium 200 may be determined using a separate thermal resistance calculator under the same conditions as the light emitting diodes 100. It can also be calculated.

For example, the heat resistance calculator includes a heater 100 ′, a second power supply unit 400 ′ for supplying power to the heater 100 ′, and a second heat transfer medium 200 bonded to the heater 100 ′. '), A second heat dissipating medium 300' bonded to the second heat transfer medium 200 ', and a first bonding surface and a second bonding surface of the second heat transfer medium 200' bonded to the heater 100 '. The second temperature sensor unit 500 'for measuring the temperature difference between the second bonding surface of the second heat transfer medium 200' bonded to the heat radiating medium 300 ', and the calorific value of the heater 100' and And a second calculation unit 600 ′ that calculates a thermal resistance coefficient R of the second heat transfer medium 200 ′ from the correlation between the temperature differences of the respective joint surfaces, and includes the second calculation unit 600 ′. The thermal resistance coefficient R of the first heat transfer medium 200 may be calculated by the following equations [3a] and [3b].

Equation 3a

[Equation 3b]

는 히터(100')에 접합되는 제2열전달매체(200')의 제1접합면의 온도(T_1') 및 제2열방출매체(300')에 접합되는 제2열전달매체(200')의 제2접합면의 온도(T_2') 간의 온도차(T_1'-T_2')이고, Q_heater는 미리 결정된 상기 히터(100')의 발열량이다.Here, the equations [3a] and [3b]

Is the temperature T _{1 ′} of the first bonding surface of the second heat transfer medium 200 ′ bonded to the heater 100 ′ and the second heat transfer medium 200 ′ bonded to the second heat release medium 300 ′. a second _"and, Q is a predetermined _heater and the heater (100 _'temperature difference (T ₁ -T between _2), temperature of the contact surface (T _2), the amount of heat generated).

As the heater 100 ′, a conventional standard heater capable of providing a constant amount of heat dissipation may be used, and the present invention is not limited or limited by the type and characteristics of the heater 100 ′. For reference, in the present invention, that the light emitting diodes 100 and the heaters 100 'are provided under substantially the same conditions may mean that the light emitting diodes and the heaters are on the same heat transfer medium and heat radiating medium. Under conditions of substantially the same temperature, humidity, air volume, or the like, it may be understood that heat generated from the light emitting diode and the heater is measured using another heat transfer medium and a heat release medium having the same specification and material.

In addition, the heat transfer medium 200 and the heat release medium 300 may be commonly used in the light emitting diodes 100 or the heaters 100 'under substantially the same conditions, and may emit light under substantially the same conditions. Each of the diodes 100 and heater 100 'may be provided separately.

를 산출할 수 있으며, 제1열전달매체(200) 및 제1열방출매체(300)와 동일한 규격 및 특성을 갖는 별도의 제2열전달매체(200') 및 제2열방출매체(300')를 이용하여 제1열전달매체(200)의 열저항 계수(R)를 산출할 수 있다. 경우에 따라서는 제1열전달매체 및 제1열방출매체를 이용하여 발광다이오드(100)의

를 산출한 후, 제1열전달매체로부터 발광다이오드를 분리한 후 제1열전달매체에 히터를 접합하여 제1열전달매체의 열저항 계수(R)를 산출할 수도 있다.For example, the light emitting diodes 100 may be formed by using the first heat transfer medium 200 and the first heat release medium 300.

The second heat transfer medium 200 ′ and the second heat release medium 300 ′ having the same specifications and characteristics as the first heat transfer medium 200 and the first heat release medium 300 may be obtained. The thermal resistance coefficient R of the first heat transfer medium 200 may be calculated. In some cases, the light emitting diode 100 may be formed using a first heat transfer medium and a first heat release medium.

After calculating, the light emitting diode is separated from the first heat transfer medium, and then a heater is bonded to the first heat transfer medium to calculate the thermal resistance coefficient R of the first heat transfer medium.

Meanwhile, an upper portion of the heater 100 ′ may be covered by an encapsulation layer, such as epoxy or silicone resin, which seals the upper portion of the light emitting diode 100 to form the same condition as the light emitting diode 100. Therefore, the heat generated from the light emitting diodes 100 and the heater 100 'is mostly transmitted to the first or second heat transfer medium 200' bonded to the lower part of the light emitting diodes 100 and the heater 100 '. Can be. In some cases, conventional glass and other synthetic resins may be covered instead of epoxy or silicone resin, and the present invention is not limited or limited by the type and characteristics of an encapsulation layer.

In the above-described and illustrated embodiments of the present invention, an example of calculating the light quantity efficiency of only one light emitting diode 100 is described. However, in some cases, as illustrated in FIG. 3, the plurality of light emitting diodes 100 may be spaced apart from each other. It is also possible to simultaneously measure the light quantity efficiency of the plurality of light emitting diodes 100 in a light emitting diode array (LED ARRAY) provided to have a predetermined arrangement. In addition, it is also possible to calculate the light quantity efficiency of the plurality of light emitting diodes using one calculation unit.

On the other hand, Table 1 below summarizes the catalog value of the commercial product (1W Power LED) and the light quantity efficiency measurement results (at IF = 350 ㎃, TA = 25 ℃) of the commercial product according to the present invention.

[Table 1] Comparison of catalog values and measured values of commercial products

As can be seen from Table 1 above, in the case of commercially available blue light emitting diodes, the efficiency of the catalog is 33.1%. According to the results measured according to the present invention, the efficiency of commercially available blue light emitting diodes is 33.3%. In the case of the green light emitting diode, the efficiency of the catalog value is 13.0%, and according to the results measured according to the present invention, it can be seen that the efficiency of the commercial green light emitting diode is 13.4%. You can see that the catalog's numerical value is very close to the efficiency.

In the above-described and illustrated embodiments of the present invention, for example, the heat is simply released by the structural characteristics of the heat transfer medium. However, in some cases, as shown in FIG. A separate cooling device 700 may be provided. For example, a conventional cooling fan may be used as the cooling device 700, and other conventional cooling means may be used.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

100: light emitting diode 110: epoxy
200: heat transfer medium 300: heat release medium
400: power supply unit 500: temperature sensor unit
600: calculator 100 ': heater

Claims (15)

In the method of measuring the efficiency of a light emitting diode (LED),
Measuring a calorific value of the light emitting diode; And
Calculating a light quantity efficiency by using the calorific value of the light emitting diodes. The method of claim 1,
The light quantity efficiency of the light emitting diode is calculated by the following formula [1].

Equation [1]

Wherein, in the equation [1], Q _LED is a heat generation amount of the light emitting diode, and P _input is an input power (V * I) applied to the light emitting diode. The method of claim 2,
The calorific value (Q _LED ) of the light emitting diode is
A first heat transfer medium and a first heat transfer medium stacked on the first heat release medium are specified, wherein the light emitting diode is positioned on a first bonding surface of the first heat transfer medium, and the heat transfer by the light emitting diode is performed. If it stays uniform,
A method for measuring the efficiency of a light emitting diode, which is calculated by the following equation [2].

Equation [2]

(However, in the equation [2]

Temperature difference between the first temperature of the first bonding surface (T ₁₎ and the first temperature of the second bonding side of the first heat transfer medium is joined to the heat-emitting medium (T ₂₎ of the first heat transfer medium to be bonded to the light-emitting diode ( T ₁ -T ₂ ), and R is a thermal resistance coefficient of the first heat transfer medium.) The method of claim 3,
The thermal resistance coefficient (R) of the first heat transfer medium is a method of measuring the efficiency of the light emitting diode, characterized in that a predetermined constant. The method of claim 3,
The thermal resistance coefficient R of the first heat transfer medium is
Under a condition substantially the same as a condition for measuring the calorific value of the light emitting diode, a heater, a second heat radiating medium, and a second heat transfer medium stacked on the second heat radiating medium are specified using the second heater. When placed on the first bonding surface of the heat transfer medium, the heat transfer by the heater is kept uniform,
A method for measuring the efficiency of a light emitting diode, which is calculated by the following equation [3].

Equation [3]

(However, in the equation [3]

Is the temperature T _{1 ′} of the first bonding surface of the second heat transfer medium bonded to the heater and the temperature T _{2 ′} of the second bonding surface of the second heat transfer medium bonded to the second heat radiating medium. Temperature difference (T _{1 '} -T _2' ), and Q _heater is a predetermined calorific value of the heater) The method of claim 5,
Each heat transfer medium and each heat release medium,
A method of measuring the efficiency of a light emitting diode, characterized in that it is commonly used for the light emitting diode or the heater under substantially the same conditions, or provided separately for the light emitting diode and the heater under substantially the same conditions. The method of claim 6,
The upper portion of the light emitting diode and the heater is covered by an encapsulation layer,
The heat generated from the light emitting diode and the heater is mainly transmitted to the first or second heat transfer medium bonded to the lower portion of the light emitting diode and the heater under the substantially same conditions. The method of claim 5,
The temperature of each joining surface is measured by a temperature sensor unit provided on each joining surface,
The temperature sensor unit measuring the efficiency of the light emitting diode, characterized in that using any one of the thermocouple (thermocoupl), thermopile (Thermopile) and Resistance Temperature Detector (RTD). The method of claim 1,
The light emitting diodes are provided to have a predetermined arrangement such that a plurality of the light emitting diodes are spaced apart from each other.
A method of measuring the efficiency of a light emitting diode, characterized in that for measuring the light quantity efficiency of the plurality of light emitting diodes at the same time. In the efficiency measuring device of a light emitting diode (LED),
A first power supply unit supplying power to the light emitting diodes;
A first heat transfer medium bonded to the light emitting diodes;
A first heat radiating medium bonded to the heat transfer medium;
A first temperature sensor unit for measuring a temperature difference between a first bonding surface of the first heat transfer medium bonded to the light emitting diode and a second bonding surface of the first heat transfer medium bonded to the first heat emitting medium; And
And a first calculation unit calculating a light quantity efficiency of the light emitting diode based on a correlation between the heat generation amount of the light emitting diode and an input power applied to the light emitting diode. The method of claim 10,
Wherein the calculating unit calculates the light quantity efficiency according to the following formula [1] and formula [2] efficiency measuring device of the light emitting diode.

Equation [1]

Equation [2]

In the above Equation [1], Q _LED is a heat generation amount of the light emitting diode, and P _input is an input power (V * I) applied to the light emitting diode.
In equation [2]

Between the first junction temperature side (T ₁₎ and the temperature of the second bonding side of the first heat transfer medium is joined to the first heat medium (T ₂₎ of the first heat transfer medium is joined to the light emitting diode Temperature difference (T ₁ -T ₂ ), and R is a thermal resistance coefficient of the first heat transfer medium.) The method of claim 11,
Further comprising a heat resistance calculation unit for calculating a heat resistance coefficient (R) of the first heat transfer medium under substantially the same conditions as the light emitting diode,
The heat resistance calculation unit,
heater;
A second power supply unit supplying power to the heater;
A second heat transfer medium bonded to the heater;
A second heat radiating medium bonded to the second heat transfer medium;
A second temperature sensor unit for measuring a temperature difference between a first bonding surface of the second heat transfer medium bonded to the heater and a second bonding surface of the second heat transfer medium bonded to the second heat radiating medium; And
And a second calculation unit configured to calculate a thermal resistance coefficient (R) of the second heat transfer medium from a correlation between the amount of heat generated by the heater and the temperature difference between the bonding surfaces.
The second operation unit calculates the thermal resistance coefficient (R) of the first heat transfer medium according to the following equation [3].

Equation [3]

(However, in the equation [3]

Is the temperature T _{1 ′} of the first bonding surface of the second heat transfer medium bonded to the heater and the temperature T _{2 ′} of the second bonding surface of the second heat transfer medium bonded to the second heat radiating medium. Temperature difference (T _{1 '} -T _2' ), Q _heater is a predetermined calorific value of the heater) The method of claim 12,
The heat transfer medium, the heat release medium and the temperature sensor unit,
An apparatus for measuring the efficiency of a light emitting diode, wherein the light emitting diode or the heater is used in common under substantially the same conditions, or provided separately according to the light emitting diode and the heater under substantially the same conditions. The method of claim 13,
The upper portion of the light emitting diode and the heater is covered by an encapsulation layer,
The heat generated from the light emitting diode and the heater is transferred to the first or second heat transfer medium bonded to the lower portion of the light emitting diode and the heater under the substantially same conditions. The method of claim 12,
Each of the temperature sensor units includes any one of a thermocouple, a thermopile, and a resistance temperature detector (RTD).

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