TWI616513B - Method for measuring temperature of light emitting diode chip and temperature-sensitive polymer used therein - Google Patents

Abstract

A method for measuring temperature of a light-emitting diode wafer, comprising the steps of: providing a polymer material comprising a support and fluorescent molecules, a crosslinking agent, an anion group and a water molecule dispersed in the support; The fluorescent molecules are coated in the support body, and the fluorescent molecules change according to changes in the external environment temperature; the high-frequency materials are excited by the light sources of different wavelengths, and the light intensity values of the fluorescent materials of the polymer materials under different temperature conditions are collected, Obtaining a correlation database of the wavelength of the light source, the temperature of the polymer material, and the intensity of the fluorescent light; providing a light-emitting diode package structure with a solid crystal wire, placing the polymer material on the LED to be tested and energizing The fluorescent light intensity of the thermal polymer material is measured and compared with a database to obtain a temperature of the light emitting diode wafer.

Description

Temperature measuring method of light-emitting diode wafer and heat-sensitive polymer material used material

The present invention relates to a method for measuring the temperature of a light-emitting diode wafer and a heat-sensitive polymer material used in the method.

As a highly efficient light source, light emitting diode (LED) has many characteristics such as environmental protection, power saving and long life, and has been widely used in various fields.

Before being applied to various fields, the light-emitting diode needs to be packaged to protect the light-emitting diode wafer, thereby achieving high luminous efficiency and long service life. A general LED package structure generally includes a substrate with an electrode attached to the surface, a reflective cup disposed on the substrate, a light-emitting diode chip disposed at the bottom of the reflective cup and electrically connected to the electrode, and covering the light-emitting diode A transparent encapsulation layer of the wafer.

When the LED chip is in operation, the electrical energy is converted into light energy, and at the same time, the heat is released, which causes the temperature of the LED chip to rise, which affects the service life of the LED package structure. Therefore, measuring the temperature of the light-emitting diode wafer in the light-emitting diode package structure is critical for predicting the service life of the light-emitting diode package structure. However, in a general LED package structure, the LED chip is covered by a transparent encapsulation layer, and the LED chip cannot be directly measured.

In view of this, it is necessary to provide an effective temperature measuring method for a light-emitting diode wafer. The present invention also provides a heat sensitive polymer material used in the method.

A method for measuring a temperature of a light-emitting diode wafer, comprising the steps of: providing a heat-sensitive polymer material comprising a heat-sensitive polymer support and a fluorescent molecule dispersed in the heat-sensitive polymer support; a coupling agent, an anion group, and a water molecule, wherein the structure of the thermosensitive polymer support is Wherein R is a saturated alkyl group having 3 carbon atoms, and the structure of the fluorescent molecule is Wherein x is 1 or 2, and the fluorescent molecule is coated in the heat-sensitive polymer support body, and when the temperature of the external environment is increased, the heat-sensitive polymer support body is gradually shrunk, thereby causing the coating to have high heat sensitivity. The fluorescence intensity of the fluorescent molecule in the molecule is gradually increased, and when the temperature of the external environment is lowered, the heat-sensitive polymer support gradually expands, thereby causing the fluorescent molecule of the fluorescent molecule coated in the thermosensitive polymer. The light intensity is gradually weakened, and the negative ion group prevents the fluorescent molecule from cross-linking with the heat-sensitive polymer support, the crosslinking agent promotes crosslinking of the heat-sensitive polymer support; and the light source is excited by a light source of a certain wavelength The heat sensitive polymer material is collected, and the light intensity value of the light-sensitive polymer material at a wavelength of the light source and the different temperature conditions is collected, and the wavelength value of the light source is converted, and the heat-sensitive polymer material is repeatedly collected in different a light intensity value of the fluorescent light under temperature conditions, thereby obtaining a correlation function database between the wavelength of the light source, the temperature of the thermosensitive polymer material, and the intensity value of the fluorescent light; A light-emitting diode package structure having a solid crystal wire, the thermosensitive polymer material is placed on a light-emitting diode wafer to be tested, and the light-emitting diode chip to be tested is electrically light-emitting, and the heat sensitivity is measured by a spectroscopic method. The fluorescence intensity of the polymer material is matched by the light intensity value of the fluorescent light and the wavelength of the light source emitted from the light emitting diode chip to be detected, and the light intensity value and wavelength of the corresponding fluorescent light in the data library, thereby obtaining The temperature of the light-emitting diode wafer to be tested.

A heat-sensitive polymer material comprising a heat-sensitive polymer support and fluorescent molecules, a crosslinking agent, an anion group and a water molecule dispersed in the heat-sensitive polymer support, wherein the heat sensitive property is high The structure of the molecular support is Wherein R is a saturated alkyl group having 3 carbon atoms, and the structure of the fluorescent molecule is Where x is 1 or 2.

In the present invention, the heat-sensitive polymer support gradually shrinks (expands) as the temperature of the external environment increases (decreases), thereby causing the fluorescence intensity of the fluorescent molecule coated in the heat-sensitive polymer support body. The gradual enhancement (attenuation), by using the relationship between the fluorescence intensity of the fluorescent molecule and the temperature, it is only necessary to measure the fluorescence intensity of the thermosensitive polymer material, and the temperature of the light-emitting diode wafer can be obtained. .

100‧‧‧Thermal polymer materials

10‧‧‧Thermal polymer support

20‧‧‧Fluorescent molecules

30‧‧‧Water molecules

40‧‧‧negative ionic groups

50‧‧‧crosslinking agent

60‧‧‧Light emitting diode package structure

61‧‧‧ electrodes

62‧‧‧Substrate

63‧‧‧Reflection Cup

64‧‧‧Light Emitter Wafer

70‧‧‧Transparent encapsulation layer

1 is a flow chart showing a method of measuring the temperature of a light-emitting diode wafer in the present invention.

2 is a schematic diagram showing the endothermic reaction of the thermosensitive polymer in the step S101 of the temperature measuring method of the light-emitting diode wafer of FIG. 1.

3 is a schematic diagram showing the exothermic reaction of the thermosensitive polymer in the step S101 of the temperature measuring method of the light-emitting diode wafer of FIG. 1.

4 is a spectrum of a temperature sensitive polymer material in step S102 of the temperature measuring method of the light emitting diode wafer of FIG. 1.

Figure 5 is a graph showing the distribution of temperature and peak intensity of fluorescence in the spectrum shown in Figure 4.

6 is a cross-sectional view showing a light emitting diode package structure in step S103 of the temperature measuring method of the light emitting diode wafer of FIG. 1.

Referring to FIG. 1 , a flow chart of a method for measuring temperature of a light-emitting diode wafer according to an embodiment of the present invention is shown. The method for measuring temperature of the LED chip includes the following steps: In step S101, referring to FIG. 2 and FIG. 3, a heat-sensitive polymer material 100 including a heat-sensitive polymer support 10 and fluorescent light dispersed in the heat-sensitive polymer support 10 is provided. Molecule 20, water molecule 30, negative ion group 40, and crosslinker 50.

The structural formula of the heat-sensitive polymer support 10 is Wherein R is a saturated alkyl group having 3 carbon atoms. The saturated alkyl group R is one of an isopropyl group, a propyl group, and a t-butyl group. The molecular chains of the thermosensitive polymer support 10 are alternately in a network structure.

The thermosensitive polymer support 10 has different degrees of crosslinking under different external ambient temperature conditions. The molecular spacing of the thermosensitive polymer support 10 changes as the temperature of the external environment changes. When the temperature of the external environment is increased, the heat-sensitive polymer support 10 absorbs external heat and the temperature rises, and the degree of crosslinking of the heat-sensitive polymer support 10 becomes large, and the molecular spacing of the heat-sensitive polymer support 10 varies. This gradually becomes smaller, causing the heat-sensitive polymer support 10 to shrink. When the temperature of the external environment is lowered, the heat-sensitive polymer support 10 releases heat to the outside and the temperature is lowered, and the degree of crosslinking of the heat-sensitive polymer support 10 becomes smaller, and the molecular spacing of the heat-sensitive polymer support 10 varies. As the size gradually increases, the heat-sensitive polymer support 10 expands. The endothermic reaction and the exothermic reaction of the thermosensitive polymer support 10 are reversible.

The heat-sensitive polymer support 10 also has a minimum critical solution temperature. The lowest critical solution temperature of the thermosensitive polymer support 10 was 32 °C. When the temperature of the heat-sensitive polymer support 10 is lower than 32° C., the heat-sensitive polymer support 10 has a small cross-linking, and the thermosensitive polymer support 10 has a large molecular pitch, and the thermosensitive polymer support 10 is in the heat-sensitive polymer support 10 . The hydrophilic group guanamine bond has a strong hydrogen bonding action with the water molecule 30 dispersed in the heat-sensitive polymer support 10, and the heat-sensitive polymer support 10 mainly has a hydrophilic action. On the other hand, when the temperature of the heat-sensitive polymer support 10 is higher than 32 ° C, the degree of crosslinking of the heat-sensitive polymer support 10 becomes large, and the molecular pitch of the heat-sensitive polymer support 10 becomes small, and the heat-sensitive polymer support The hydrogen bond between the hydrophilic group guanamine bond and the water molecule 30 dispersed in the heat-sensitive polymer support 10 in the body 10 is destroyed, and the heat-sensitive polymer support 10 mainly has a hydrophobic action.

The structural formula of the above fluorescent molecule 20 is Where x is 1 or 2.

The fluorescent molecules 20 are coated in the heat-sensitive polymer support 10. The fluorescence intensity of the fluorescent molecules 20 changes as the pitch of the thermosensitive polymer support 10 changes.

The fluorescent molecule 20 is an organic fluorescent molecule. The intensity of the fluorescent light of the fluorescent molecule 20 is related to the length of the distance between the fluorescent molecule 20 and the water molecule 30. As described above, when the temperature of the external environment is increased, the molecular spacing of the heat-sensitive polymer support 10 becomes smaller, and the heat-sensitive polymer support 10 is gradually shrunk, thereby causing coating on the heat-sensitive polymer support. The distance between the fluorescent molecules 20 in the 10 and the water molecules 30 dispersed in the thermosensitive polymer support 10 is gradually shortened, so that the interaction between the fluorescent molecules 20 and the water molecules 30 is gradually increased. The fluorescence intensity of the molecule 20 is gradually enhanced. On the other hand, when the temperature of the external environment is lowered, the molecular spacing of the heat-sensitive polymer support 10 becomes larger, and the heat-sensitive polymer support 10 gradually expands, thereby causing the distance between the fluorescent molecules 20 and the water molecules 30 to gradually change. The growth of the fluorescent molecules 20 and the water molecules 30 is gradually reduced, and the fluorescence intensity of the fluorescent molecules 20 is gradually weakened.

The negative ion group 40 is easily bonded to the thermosensitive polymer support 10. The negative ion group 40 prevents the fluorescent molecule 20 from being crosslinked with the thermosensitive polymer support 10. In this embodiment, the negative ionic group 40 is a sulfonate (-SO3-).

The crosslinking agent 50 can promote crosslinking of the molecular chain of the thermosensitive polymer support 10. In the endothermic reaction, the crosslinking agent 50 can accelerate the crosslinking reaction rate of the molecular chain of the thermosensitive polymer support 10 and shorten the reaction time. In this embodiment, the structural formula of the crosslinking agent 50 is The crosslinking agent 50 is methylenebis acrylamide.

The heat-sensitive polymer support 10 undergoes the above reaction in a certain temperature range. When the temperature value exceeds the range, the molecular spacing of the heat-sensitive polymer support 10 does not change, that is, the heat-sensitive polymer support 10 Temperature changes outside the range do not produce a corresponding change.

The temperature range of the heat-sensitive polymer support 10 is related to the fluorescent molecules 20, the negative ion groups 40, and the crosslinking agent 50 dispersed in the heat-sensitive polymer support 10.

Step S102, exciting the thermosensitive polymer material 100 with a light source of a certain wavelength (not shown), and collecting the peak value of the fluorescent light intensity of the thermosensitive polymer material 100 at a source of the wavelength and different temperature conditions, and then converting The wavelength value of the light source repeatedly collects the peak intensity of the fluorescent light of the thermosensitive polymer material 100 under different temperature conditions, thereby obtaining a wavelength between the light source, the temperature of the thermosensitive polymer material 100, and the peak value of the fluorescent light intensity. Corresponding function association database;

Referring to FIG. 4 and FIG. 5 together, for example, the saturated alkyl group R in the thermosensitive polymer support 10 is an isopropyl group, and the structural formula of the fluorescent molecule 20 (taken x=2) is The negative ionic group 40 is a sulfonate group, and the crosslinking agent 50 is methylene bis acrylamide.

The temperature-sensitive polymer support 10 has an acquisition temperature in the range of 25 ° C to 45 ° C. The thermosensitive polymer material 100 is excited by a blue light monochromatic light source having a wavelength of 456 nm, and the thermosensitive polymer material 100 is collected by a spectrometer (not shown) at 25 ° C, 30 ° C, 34 ° C, 36 ° C, 38. The spectra at seven different temperature conditions of °C, 40 °C, and 45 °C, that is, the spectrum of the thermosensitive polymer material 100 under the same wavelength of light source and different temperature conditions.

Referring specifically to Figure 4, the abscissa of the spectrum represents the wavelength, the wavelength range of the spectrum is 470 nm - 750 nm, the minimum scale value is 10 nm, and the ordinate indicates the fluorescence intensity. The seven spectral lines in the spectrum correspond to the spectra of the thermosensitive polymer material 100 at 25 ° C, 30 ° C, 34 ° C, 36 ° C, 38 ° C, 40 ° C, and 45 ° C, respectively, from bottom to top. The peaks of the fluorescence intensity of the seven spectral lines in the spectrum correspond to wavelengths of 560 nm.

Fig. 5 is a graph showing the relationship between the temperature of the thermosensitive polymer material 100 and the peak of the fluorescence intensity under excitation of a light source having a wavelength of 456 nm. As can be seen from the figure, the peak intensity of the fluorescent light changes rapidly in the interval of 30 ° C to 38 ° C, and the peak value of the fluorescent light intensity changes slowly below 30 ° C and above 38 ° C. In order to accurately reflect the relationship between the temperature of the thermosensitive polymer material 100 and the peak of the fluorescence intensity under the excitation of a light source having a wavelength of 456 nm, the spectrum acquisition frequency, such as temperature, may be increased in the range of 30 ° C to 38 ° C. The spectrum was acquired every time 0.5 °C was changed. In this embodiment, the minimum temperature change that the thermosensitive polymer material 100 can resolve is 0.2 ° C, that is, the temperature of the thermosensitive polymer material 100 in the temperature range of 25 ° C to 45 ° C. A change of 0.2 ° C causes a change in the peak intensity of the fluorescent light of the thermosensitive polymer material 100.

It is easy to understand that after replacing the light source of different wavelengths, the above steps can be repeated to detect the fluorescence intensity peaks of the light source of different wavelengths and the temperature of the thermosensitive polymer material 100 at different temperatures, and obtain the wavelength of the light source and the temperature sensitive polymer material 100. Correlation function correlation database between the temperature and the peak value of the fluorescence intensity.

In other embodiments, the light source can select a monochromatic light source whose wavelength is continuously adjustable in the visible light range, and correspondingly collect the fluorescent light intensity peak of the temperature-continuously adjustable light source of the thermosensitive polymer material 100 at different temperatures. A correlation function correlation database between the wavelength of the light source, the temperature of the thermosensitive polymer material 100, and the peak of the fluorescence intensity is obtained.

Step S103, referring to FIG. 6, providing a light-emitting diode package structure 60 that has been bonded and grounded, and placing the heat-sensitive polymer material 100 on the light-emitting diode wafer 64 to be tested, so that the light-emitting diode to be tested is The bulk wafer 64 is electrically illuminated, and the peak intensity of the fluorescent light of the thermosensitive polymer material 100 is measured by a spectroscopic diagram (not shown), and the peak of the fluorescent light intensity and the wavelength of the light source emitted from the LED substrate 64 to be tested are measured. The temperature of the fluorescent diode chip 64 to be tested can be obtained by matching the corresponding fluorescence intensity peak and wavelength in the database.

The LED package structure 60 includes a substrate 62 on the surface of which the electrode 61 is mounted, a reflective cup 63 disposed on the substrate 62, and a light-emitting diode wafer 64 to be tested that is disposed at the bottom of the reflective cup 63 and electrically connected to the electrode 61. . The LED array 64 to be tested is electrically connected to the electrode 61 by a wire (not shown).

The thermosensitive polymer material 100 is directly coated on the LED substrate 64, and the transparent encapsulating layer 70 is covered on the thermosensitive polymer material 100. Of course, the thermosensitive polymer material 100 may also be incorporated into the transparent encapsulation layer 70, and the transparent encapsulation layer 70 may be overlaid on the LED substrate 64. The transparent encapsulation layer 70 is a transparent material of silicone, epoxy or other polymer.

The electrode 61 is electrically connected to the external power source to cause the light-emitting diode wafer 64 to emit light. The LED wafer 64 is preferably a blue-emitting gallium nitride-based light-emitting diode wafer. A part of the blue light emitted from the LED wafer 64 is applied to the thermosensitive polymer material 100. Excited, the thermosensitive polymer material 100 is excited by the blue light to emit yellow-green light, which is mixed with the remaining blue light emitted by the light-emitting diode wafer 64 to form white light.

The fluorescence intensity of the thermosensitive polymer material 100 in the light-emitting diode package structure 60 in the operating state is measured by a spectral discussion (not shown), and the peak intensity of the fluorescent light of the heat-sensitive polymer material 100 is The wavelength of the light emitted by the LED array 64 to be tested matches the peak and wavelength of the corresponding fluorescent light intensity in the database, thereby obtaining the temperature of the LED array 64 to be tested.

In the present invention, the heat-sensitive polymer support 10 is gradually shrunk (expanded) as the temperature of the external environment increases (decreases), thereby causing the fluorescent molecules 20 to be coated in the heat-sensitive polymer support 10. The gradual enhancement (attenuation) of the fluorescence intensity, by using the relationship between the fluorescence intensity of the fluorescent molecule 20 and the temperature, it is only necessary to measure the fluorescence intensity of the thermosensitive polymer material 100. The temperature of the photodiode wafer 64. Since a slight temperature change of the thermosensitive polymer material 100 causes a change in the fluorescence intensity of the thermosensitive polymer material 100, the temperature measurement method of the light-emitting diode wafer 64 is close to the light emission. The actual temperature of the polar body wafer 64.

It can be understood that, in order to make the obtained result more accurately reflect the actual temperature of the LED wafer 64, when the thermosensitive polymer material 100 is incorporated into the transparent encapsulation layer 70, the thermosensitive polymer material 100 is transparent. The distribution in the encapsulation layer 70 may be uneven, for example, the thermosensitive polymer material 100 is concentrated around the LED array 64.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by persons skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

Claims (10)

A method for measuring a temperature of a light-emitting diode wafer, comprising the steps of: providing a heat-sensitive polymer material comprising a heat-sensitive polymer support and a fluorescent molecule dispersed in the heat-sensitive polymer support; a coupling agent, an anion group, and a water molecule, wherein the structure of the thermosensitive polymer support is Wherein R is a saturated alkyl group having 3 carbon atoms, and the structure of the fluorescent molecule is Wherein x is 1 or 2, and the fluorescent molecule is coated in the heat-sensitive polymer support body, and when the temperature of the external environment is increased, the heat-sensitive polymer support body is gradually shrunk, thereby causing the coating to have high heat sensitivity. The fluorescence intensity of the fluorescent molecule in the molecule is gradually increased, and when the temperature of the external environment is lowered, the heat-sensitive polymer support gradually expands, thereby causing the fluorescent molecule of the fluorescent molecule coated in the thermosensitive polymer. The light intensity is gradually weakened, and the negative ion group prevents the fluorescent molecule from cross-linking with the heat-sensitive polymer support, and the crosslinking agent promotes crosslinking of the heat-sensitive polymer support, and the heat-sensitive polymer support The minimum critical solution temperature is 32 ° C; the thermosensitive polymer material is excited by a light source of a certain wavelength, and the intensity value of the fluorescent polymer at the wavelength of the light source and the temperature under different temperature conditions is collected, and then converted. a wavelength value of the light source, and repeatedly collecting the intensity value of the fluorescent material of the thermosensitive polymer material under different temperature conditions, thereby obtaining a wavelength of the light source, a temperature of the thermosensitive polymer material, and Corresponding function correlation database between the light intensity values of the light; providing a light-emitting diode package structure with a solid-crystal wire bonding, placing the heat-sensitive polymer material on the light-emitting diode chip to be tested, so that the The light-emitting diode chip to be tested is electrically light-emitting, and the fluorescence intensity of the heat-sensitive polymer material is measured by a spectroscopic measurement, and the light intensity value of the fluorescent light and the wavelength of the light emitted by the light-emitting diode wafer to be tested are The light intensity values and wavelengths of the corresponding fluorescent lights in the database are matched to obtain the temperature of the light emitting diode chip to be tested. The method for measuring the temperature of a light-emitting diode wafer according to claim 1, wherein the heat-sensitive polymer support has a different degree of crosslinking at different temperatures, and the temperature of the heat-sensitive polymer support increases. The degree of crosslinking of the heat-sensitive polymer support is increased, and the molecular spacing of the heat-sensitive polymer support is reduced, and the heat-sensitive polymer support is gradually shrunk, and when the temperature of the heat-sensitive polymer support is lowered The degree of crosslinking of the heat-sensitive polymer support is reduced, and the molecular spacing of the heat-sensitive polymer support is increased, and the heat-sensitive polymer support gradually expands. The method for measuring the temperature of a light-emitting diode wafer according to claim 2, wherein the endothermic reaction and the exothermic reaction of the heat-sensitive polymer support are reversible. The method for measuring the temperature of a light-emitting diode wafer according to the third aspect of the invention, wherein, when the heat-sensitive polymer support is gradually shrunk, the fluorescent molecule and the water molecule dispersed in the heat-sensitive polymer support The action distance is gradually shortened, and the interaction between the fluorescent molecules and the water molecules dispersed in the thermosensitive polymer support gradually becomes stronger, and the fluorescence intensity of the fluorescent molecules is enhanced, when the thermosensitive polymer supports When the body gradually expands, the interaction distance between the fluorescent molecules and the water molecules becomes longer, the interaction between the fluorescent molecules and the water molecules becomes weaker, and the fluorescence intensity of the fluorescent molecules gradually decreases. The method for measuring the temperature of a light-emitting diode wafer according to claim 1, wherein the heat-sensitive polymer material directly covers the light-emitting diode wafer, and then the transparent packaging layer is covered with the heat-sensitive layer. On polymer materials. The method for measuring a temperature of a light-emitting diode wafer according to claim 1, wherein the heat-sensitive polymer support has a certain temperature response range, when the temperature is super When the temperature response range is exceeded, the molecular distance of the heat-sensitive polymer support does not change. The method for measuring the temperature of a light-emitting diode wafer according to the first aspect of the invention, wherein the saturated alkyl group R in the heat-sensitive polymer support is one of an isopropyl group, a propyl group or a t-butyl group. The negative ionic group is a sulfonic acid group, and the fluorescent molecular structure is The crosslinking agent is methylenebis acrylamide. The method for measuring the temperature of a light-emitting diode wafer according to claim 6, wherein the temperature-sensitive polymer support has a temperature response range of 25 ° C to 45 ° C. A heat-sensitive polymer material comprising a heat-sensitive polymer support and a fluorescent molecule, a crosslinking agent, an anion group and a water molecule dispersed in the heat-sensitive polymer support, wherein the structure of the heat-sensitive polymer support is Wherein R is a saturated alkyl group having 3 carbon atoms, and the structure of the fluorescent molecule is Where x is 1 or 2, when the temperature of the external environment increases, the heat-sensitive polymer support gradually shrinks, and the fluorescence intensity of the fluorescent molecule gradually increases, and when the temperature of the external environment decreases, the heat sensitivity is high. The molecular support gradually expands, and the fluorescence intensity of the fluorescent molecule gradually decreases. The minimum critical solution temperature of the thermosensitive polymer support is 32 °C. The heat-sensitive polymer material according to claim 9, wherein the negative ion group prevents the fluorescent molecule from being crosslinked with the heat-sensitive polymer support, and the crosslinking agent promotes the heat-sensitive polymer support Cross-linking.