A method and system for determining the surface junction temperature of an LED

Abstract

The present invention relates to a method and system for determining the surface junction temperature of an LED, and relates to the field of the surface junction temperature of an LED. The method includes: obtaining the spectral data of the LED surface; determining the surface junction temperature of the LED according to the spectral data of the LED surface and a matrix model. The present invention improves the measurement accuracy by non-contact measurement of the junction temperature of the LED.

Description

Technical Field

[0001] The present invention relates to the field of LED surface junction temperature, and particularly to a method and system for determining the LED surface junction temperature. Background Art

[0002] Traditional methods for measuring the thermal characteristics of the LED surface, such as the physical direct contact method, cannot test small devices, and the error caused by the peak wavelength observation method is too large. These defects make it impossible for traditional measurement methods to effectively analyze the thermal characteristics of LED chips. Summary of the Invention

[0003] The object of the present invention is to provide a method and system for determining the LED surface junction temperature, so as to improve the measurement accuracy by non-contact measurement of the junction temperature of the LED.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] A method for determining the LED surface junction temperature includes:

[0006] Obtaining the LED surface spectral data;

[0007] Determining the LED surface junction temperature according to the LED surface spectral data and the matrix model.

[0008] Optionally, the obtaining of the LED surface spectral data specifically includes:

[0009] Obtaining the LED surface spectral data by using a microscopic hyperspectral imaging system.

[0010] Optionally, the determination process of the matrix model includes:

[0011] Obtaining the surface spectral data of the test point at different currents and the surface junction temperature data of the test point at different currents;

[0012] Determining the coefficient information of the matrix model according to the surface spectral data of the test point at different currents and the surface junction temperature data of the test point at different currents; the coefficient information includes a first coefficient, a second coefficient, a third coefficient, and a fourth coefficient;

[0013] Determining the matrix model according to the coefficient information.

[0014] Optionally, the expression of the matrix model is:

[0015] A = αI 2 + βT 2 + χI + δT + A0

[0016] Among them, A is a matrix model, I is the current, T is the temperature, A0 is the coefficient of the set reference point, α is the first coefficient, β is the second coefficient, χ is the third coefficient, and δ is the fourth coefficient.

[0017] An LED surface junction temperature determination system includes:

[0018] An acquisition module for acquiring LED surface spectral data;

[0019] An LED surface junction temperature determination module for determining the LED surface junction temperature according to the LED surface spectral data and the matrix model.

[0020] Optionally, the acquisition module specifically includes:

[0021] An acquisition unit for acquiring LED surface spectral data by using a microscopic hyperspectral imaging system.

[0022] Optionally, the determination process of the matrix model includes:

[0023] Acquiring the surface spectral data of the test point at different currents and the surface junction temperature data of the test point at different currents;

[0024] Determining the coefficient information of the matrix model according to the surface spectral data of the test point at different currents and the surface junction temperature data of the test point at different currents; the coefficient information includes the first coefficient, the second coefficient, the third coefficient, and the fourth coefficient;

[0025] Determining the matrix model according to the coefficient information.

[0026] Optionally, the expression of the matrix model is: A = αI 2 + βT 2 + χI + δT + A0

[0027] Among them, A is a matrix model, I is the current, T is the temperature, A0 is the coefficient of the set reference point, α is the first coefficient, β is the second coefficient, χ is the third coefficient, and δ is the fourth coefficient.

[0028] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0029] The present invention acquires LED surface spectral data; determines the LED surface junction temperature according to the LED surface spectral data and the matrix model. By determining the LED surface junction temperature through the LED surface spectral data and the matrix model, the measurement of the junction temperature is realized without changing the working state of the LED, thereby improving the determination accuracy of the surface junction temperature. Description of the Drawings

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required in the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0031] Figure 1 Flowchart of the LED surface junction temperature determination method provided by the present invention;

[0032] Figure 2 Schematic diagram of the LED surface junction temperature determination method provided by the present invention. Detailed implementation manners

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0034] The object of the present invention is to provide an LED surface junction temperature determination method and system to improve the measurement accuracy by non-contact measurement of the junction temperature of the LED.

[0035] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0036] As Figure 1 shown, an LED surface junction temperature determination method provided by the present invention includes:

[0037] Step 101: Obtain the surface spectral data of the LED. Among them, the obtaining of the surface spectral data of the LED specifically includes: using a microscopic hyperspectral imaging system to obtain the surface spectral data of the LED.

[0038] Step 102: Determine the LED surface junction temperature according to the LED surface spectral data and the matrix model.

[0039] In practical applications, the determination process of the matrix model includes:

[0040] Obtain the surface spectral data of the test point at different currents and the surface junction temperature data of the test point at different currents; determine the coefficient information of the matrix model according to the surface spectral data of the test point at different currents and the surface junction temperature data of the test point at different currents; the coefficient information includes a first coefficient, a second coefficient, a third coefficient, and a fourth coefficient; determine the matrix model according to the coefficient information.

[0041] The present invention uses a microscopic hyperspectrometer and an infrared thermal imager to collect the spectral information and temperature information of each pixel point of the LED surface chip, and establishes a matrix model for predicting the surface temperature of the LED chip or the surface spectral data of the LED chip. The present invention uses a mathematical model to reasonably calculate and predict the junction temperature of the LED chip or the surface spectral data of the LED chip, thereby realizing the test without changing the working state of the LED, so as to make up for the shortcomings of the traditional test method.

[0042] like Figure 2 As shown, the present invention can measure the surface temperature of LED chips or the high-spectral data of LED surfaces in a non-contact manner. When the LED junction temperature data can be directly obtained, the spectrum data can be determined according to the LED junction temperature data and the matrix model. Its purpose is to calculate the temperature distribution of the LED chip based on the known light signal data and analyze the thermal characteristics of the LED chip; to calculate the distribution of the photon energy of the LED chip based on the known temperature signal data and analyze the optical characteristics of the LED chip. This test method is based on microscopic hyperspectral measurement technology and infrared thermal imaging test technology. The microscopic hyperspectral test system is used to measure the photon number, spectral peak, half-wave width and other data at each point on the LED chip. At the same time, the infrared image of the sample is collected by an infrared thermal imager, and the temperature data of each point on the surface of the LED chip is analyzed and marked to find the connection between the spectrum and temperature data of each collection point; the pixel coordinates of the collected image data are marked as rows and columns, and the connection between the spectral data and the temperature data of each row and column is found; and then the coordinate axes are used as rows and columns, and the collected temperature data and the photon number, spectral peak and other hyperspectral spectrometer collected data and the linear relationship between them are constructed into matrices, starting from the single test point data, extending to one-dimensional line data, and finally extending to two-dimensional surface data, so as to establish a theoretical matrix model that associates the spectral data emitted by the LED sample with the junction temperature of its chip surface.

[0043] The present invention also provides a specific construction process of the matrix model in practical application:

[0044] (1) Establish the connection between the data of each test point: In the experiment, the sample is placed in a stable environment, and the spectral value data P of each point of the sample under different control conditions are collected by changing different influencing parameters. In addition, under the same experimental conditions, the temperature data T of each variable at the same coordinate point is collected; define the coefficient A, which is the matrix model, and construct an elementary equation to connect the spectral data P with the temperature data T:

[0045] P=A·T (1)

[0046] Obviously, A can be solved by knowing P and T, that is,

[0047] A=P·T -1(2)

[0048] Thus, the relationship between the optical signal data and the temperature signal data of each pixel is determined.

[0049] (2) Establish the relationship between one-dimensional line data: Take the ordinate y-axis of the pixel as row n and the abscissa x-axis as column m to construct a single-column matrix and a single-row matrix O' n =(O'1 O'2 …) n , and integrate the optical signal P ij of each point and the temperature signal T ij , we get:

[0050]

[0051]

[0052]

[0053]

[0054] Then a one-dimensional model can be constructed:

[0055] P n =A (i，j+n) ×T n =(A i1 A i2 …) n (T i1 T i2 …) n (7)

[0056]

[0057] Verify the accuracy of A ij through matrix operations, and thus establish the mutual relationship between one-dimensional line data.

[0058] (3) Construct a two-dimensional mathematical model to relate the data of the surface area of the LED chip: Take the ordinate y-axis of the pixel as row n and the abscissa x-axis as column m to establish a coordinate matrix Then we have

[0059]

[0060]

[0061] Based on this, construct a matrix of optical signal data and thermal signal data

[0062]

[0063] Among them, P is the light signal data matrix, and T is the temperature signal data matrix. Through the one-dimensional model, the relationship between the LED two-dimensional plane light signal data and the temperature signal data is derived, and the matrix A is constructed, and its expression is: Through the data analysis of finite items, we further deduce to the m×n matrix model. So far, we have constructed a two-dimensional mathematical model. On the premise of clarifying certain data of the LED lamp beads, we can deduce other characteristic parameters of the LED lamp beads through this model, so as to discuss and study the characteristics of the LED chip more conveniently.

[0064] From the analysis of experimental data, it is known that under different thermal forming temperatures and input currents, the value of A will also change accordingly, that is, A is not a single invariant matrix, and will change under different input conditions. Therefore, this scheme proposes a functional expression of A between temperature T and current I, that is, the expression of the matrix model:

[0065] A=αI 2 +βT 2 +χI+δT+A0 (11)

[0066] Among them, A0 is the coefficient of the set reference point, α, β, δ, and γ are the coefficients to be determined. A is the matrix model, I is the current, T is the temperature, A0 is the coefficient of the set reference point, α is the first coefficient, β is the second coefficient, χ is the third coefficient, and δ is the fourth coefficient. Taking the most common 3×3 matrix model as an example, the optical signal data and thermal signal data are collected under different input current conditions, nine sampling points are selected, and then the relationship coefficient A is analyzed. The specific data are shown in Tables 1 and 2 below:

[0067] Table 1 Temperature data of each acquisition point when the input current is 100mA

[0068]

[0069] Table 2 Total photon energy of LED chip at 100mA current

[0070]

[0071] From this, we can deduce that the A value corresponding to each point under this condition is:

[0072]

[0073] Calculated in the same way, the A matrix values ​​for the other conditions are as follows:

[0074]

[0075]

[0076] And determine α, β, δ, and γ based on this change trend. At this point, the two-dimensional mathematical model matrix model proposed in the solution of the present invention is completed.

[0077] The present invention constructs a matrix model of the surface temperature of an LED chip or the high-spectral data of the LED chip surface: the photon energy of each point on the LED chip measured by the microscopic high-spectral technology is connected with the surface temperature of each point on the LED chip measured by the thermal imaging technology, and the photon energy and the surface temperature are combined by the coefficient matrix to establish a theoretical model related to the photon energy and the surface temperature, so that the photon energy of each point on the LED chip and the surface temperature of each point can correspond one to one. The advantages of the present invention are as follows:

[0078] 1. Realize non-contact measurement of LED junction temperature. Through the microscopic hyperspectral system and microscopic thermal imaging system, using microscopic hyperspectral technology and thermal imaging technology, collect the spectral information and thermal information of LED chips, establish relevant theoretical models, and predict the LED junction temperature through the model, so as to realize the test without changing the working state of the LED.

[0079] 2. Combine microscopic hyperspectral technology and thermal imaging technology to analyze the thermal characteristics of LED chips. Microscopic hyperspectral technology can combine LED spatial dimension information with spectral attribute information to measure and fit the area to be measured. Thermal imaging technology can measure the actual operating temperature of LED chips in real time. Combining the two technologies can more effectively analyze the thermal characteristics of LED chips.

[0080] 3. High spectral resolution and spatial resolution. Due to the high spectral resolution and spatial resolution of hyperspectral imaging technology, it can more accurately analyze the spectral information of LEDs under working conditions, making the data more precise and reducing the error of experimental results.

[0081] The present invention also provides a system for determining the surface junction temperature of an LED corresponding to the method for determining the surface junction temperature of an LED, comprising:

[0082] The acquisition module is used to obtain the LED surface spectrum data.

[0083] The LED surface junction temperature determination module is used to determine the LED surface junction temperature according to the LED surface spectrum data and the matrix model.

[0084] As an optional implementation manner, the acquisition module specifically includes:

[0085] The acquisition unit is used to acquire the LED surface spectrum data using a microscopic hyperspectral imaging system.

[0086] As an alternative implementation, the process of determining the matrix model includes:

[0087] Obtain the surface spectral data of the test point at different currents and the surface junction temperature data of the test point at different currents; determine the coefficient information of the matrix model according to the surface spectral data of the test point at different currents and the surface junction temperature data of the test point at different currents; the coefficient information includes a first coefficient, a second coefficient, a third coefficient, and a fourth coefficient; determine the matrix model according to the coefficient information.

[0088] As an alternative implementation, the expression of the matrix model is: A = αI 2 + βT 2 + χI + δT + A0

[0089] where A is the matrix model, I is the current, T is the temperature, A0 is the coefficient of the set reference point, α is the first coefficient, β is the second coefficient, χ is the third coefficient, and δ is the fourth coefficient.

[0090] The present invention constructs a matrix model by analyzing the microscopic hyperspectral image data and infrared thermal image data collected in the experiment. Through this model, the mutual derivation between the hyperspectral data on the surface of the LED chip and the surface junction temperature data of the LED chip is realized; at the same time, the main technical principle of this model is to determine the junction temperature distribution on the surface of the LED chip through a more accurate optical test method: using the coefficient matrix model calculated by the present invention, when the corresponding total photon energy is input, a more accurate theoretical temperature can be obtained, realizing the correlation between the total photon energy and the chip temperature. By inputting the total photon energy of each point on the chip, the theoretical temperature of each point on the chip is deduced, so as to more accurately predict the temperature of each point on the chip, to make up for the problems caused by the deficiencies of traditional methods for testing the surface junction temperature of LEDs, such as the inability to test smaller devices by physical direct testing methods and the large errors caused by peak wavelength measurement methods, and further analyze the thermal characteristics of LEDs more precisely and effectively.

[0091] In this specification, each embodiment is described in a progressive manner. The key points of each embodiment are the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the description in the method part.

[0092] In this article, specific examples are used to illustrate the principles and implementation manners of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. To sum up, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A method for determining the surface junction temperature of an LED, characterized in that, Including: Obtain the surface spectral data of the LED; Determine the surface junction temperature of the LED according to the surface spectral data of the LED and the matrix model; The determination process of the matrix model includes: Obtain the surface spectral data of the test point at different currents and the surface junction temperature data of the test point at different currents; Determine the coefficient information of the matrix model according to the surface spectral data of the test point at different currents and the surface junction temperature data of the test point at different currents; the coefficient information includes a first coefficient, a second coefficient, a third coefficient, and a fourth coefficient; Determine the matrix model according to the coefficient information; The expression of the matrix model is: A = αI 2 + βT 2 + χI + δT + A0 Where A is the matrix model, I is the current, T is the temperature, A0 is the coefficient of the set reference point, α is the first coefficient, β is the second coefficient, χ is the third coefficient, and δ is the fourth coefficient.

2. The method for determining the surface junction temperature of an LED according to claim 1, characterized in that The obtaining of the surface spectral data of the LED specifically includes: Use a microscopic hyperspectral imaging system to obtain the surface spectral data of the LED.

3. An LED surface junction temperature determination system, characterized in that Including: An acquisition module for obtaining the surface spectral data of the LED; An LED surface junction temperature determination module for determining the surface junction temperature of the LED according to the surface spectral data of the LED and the matrix model; The determination process of the matrix model includes: Obtain the surface spectral data of the test point at different currents and the surface junction temperature data of the test point at different currents; Determine the coefficient information of the matrix model according to the surface spectral data of the test point at different currents and the surface junction temperature data of the test point at different currents; the coefficient information includes a first coefficient, a second coefficient, a third coefficient, and a fourth coefficient; Determine the matrix model according to the coefficient information; The expression of the matrix model is: A = αI 2 + βT 2 + χI + δT + A0 Where A is the matrix model, I is the current, T is the temperature, A0 is the coefficient of the set reference point, α is the first coefficient, β is the second coefficient, χ is the third coefficient, and δ is the fourth coefficient.

4. The LED surface junction temperature determination system according to claim 3, characterized in that, The acquisition module specifically includes: An acquisition unit for using a microscopic hyperspectral imaging system to obtain the surface spectral data of the LED.

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