Method for testing wavelength of fluorescent powder based on LED packaging process

Abstract

The invention discloses a method for testing the wavelength of fluorescent powder based on an LED packaging process, and the method comprises the steps: providing a blue-light LED chip, and manufacturing a semi-finished product unit through die bonding and wire welding; taking green and red fluorescent powders with known wavelengths as reference powders, taking green and red fluorescent powders with to-be-detected wavelengths as to-be-detected powders, and respectively mixing the reference powders and the to-be-detected powders with the packaging adhesive according to the same preset proportion to prepare a reference fluorescent adhesive and a to-be-detected fluorescent adhesive; dispensing the plurality of semi-finished product units with at least three different glue output amounts, and curing to form a test sample; lightening the sample under a constant current and measuring a spectrum; performing linear fitting by taking the glue output amount of each fluorescent glue as a horizontal coordinate and taking the corresponding wavelength as a vertical coordinate to obtain a wavelength-glue amount fitting straight line and a slope of the reference powder and the powder to be measured; and calculating the wavelength of the fluorescent powder to be measured by using a preset conversion relation according to the slope difference value. According to the method, the wavelength test is embedded into the packaging process, so that the fluorescent powder wavelength rapid evaluation which is low in cost and easy to operate is realized.

Description

Technical Field

[0001] This invention relates to the field of LED packaging technology, and more specifically to a method for testing phosphor wavelengths based on the LED packaging process. Background Technology

[0002] In LED white light packaging, blue LED chips are typically used to excite yellow, green, or red phosphors to produce white light with the desired color temperature. The excitation wavelength (main emission peak) of the phosphor is a key performance parameter that directly affects the color coordinates, color temperature, and color rendering index of the final packaged device.

[0003] Currently, phosphor manufacturers or R&D laboratories typically use specialized phosphor spectral testing equipment (such as fluorescence spectrometers equipped with integrating spheres) to accurately measure the wavelength of phosphors. This equipment uses a standard light source (such as a fixed-wavelength blue laser) to excite the phosphor and then analyzes the emission spectrum using a high-precision spectrometer. However, such equipment is expensive, complex to operate, has stringent environmental requirements, and is generally not convenient to deploy at LED packaging production sites.

[0004] In the packaging process, it is often necessary to quickly verify whether the wavelength of the incoming phosphor meets the specifications, or to compare the wavelength consistency of different batches of phosphor. Due to the lack of simple and low-cost testing methods, packaging plants often have to rely on the supplier's test reports or send samples to the laboratory for testing, resulting in long feedback cycles, high costs, and the inability to achieve real-time monitoring during the production process.

[0005] Therefore, there is an urgent need to develop a phosphor wavelength testing method that can be combined with existing LED packaging processes, is simple to operate, and is low in cost, in order to meet the needs of the packaging end for rapid evaluation of phosphor performance. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a method for testing phosphor wavelength based on LED packaging process, which aims to solve the above-mentioned problems described in the prior art.

[0007] To achieve the above objectives, the present invention employs the following technical solution: A method for testing phosphor wavelengths based on LED packaging processes, characterized in that the method includes: We provide blue LED chips, which are then manufactured into semi-finished units via die bonding and wire bonding. Green and red phosphors of known wavelengths are used as reference powders, and green and red phosphors of the wavelength to be tested are used as test powders. They are mixed with encapsulating adhesive in the same predetermined ratio to prepare reference phosphor adhesive and test phosphor adhesive. The reference fluorescent adhesive and the fluorescent adhesive to be tested were applied to multiple semi-finished product units at at least three different amounts, and the samples were cured to form test samples. The sample was illuminated under constant current and the spectrum was measured. The wavelength values ​​of the excitation peak of the phosphor in each sample were recorded. Linear fitting was performed with the amount of each fluorescent adhesive as the abscissa and the corresponding wavelength as the ordinate to obtain the wavelength-adhesive amount fitting line and slope of the reference powder and the test powder. The wavelength of the phosphor to be tested is calculated using a preset conversion relationship based on the difference between the slope of the phosphor to be tested and the slope of the reference phosphor of the same color system.

[0008] According to one aspect of the above technical solution, the step of preparing a reference fluorescent adhesive and a test fluorescent adhesive by mixing green and red phosphors of known wavelengths as reference powders and green and red phosphors of the wavelength to be measured as test powders with encapsulating adhesive in the same predetermined proportions includes: Green phosphor of known wavelength is selected as the first reference powder and red phosphor of known wavelength is selected as the second reference powder. They are mixed with encapsulating adhesive in a first predetermined ratio to prepare the first reference fluorescent adhesive and the second reference fluorescent adhesive. The green phosphor and the red phosphor of the wavelength to be measured are respectively mixed with the encapsulating adhesive in the first predetermined ratio to prepare the first fluorescent adhesive to be tested and the second fluorescent adhesive to be tested.

[0009] According to one aspect of the above technical solution, the step of performing linear fitting with the amount of each fluorescent adhesive as the abscissa and the corresponding wavelength as the ordinate to obtain the wavelength-adhesive amount fitting line and slope between the reference powder and the test powder includes: Linear fitting was performed with the amount of the first and second reference fluorescent adhesives as the abscissa and the corresponding wavelength as the ordinate, respectively, to obtain the first reference wavelength-adhesive amount fitting line and the second reference wavelength-adhesive amount fitting line, and the slopes Kreference green and Kreference red were calculated respectively. Linear fitting was performed with the amount of the first and second fluorescent adhesives to be tested as the abscissa and the corresponding wavelength as the ordinate, respectively, to obtain the first wavelength-adhesive amount fitting line and the second wavelength-adhesive amount fitting line, and the slopes K_tested green and K_tested red were calculated respectively.

[0010] According to one aspect of the above technical solution, in the step of mixing phosphor and encapsulating adhesive, the same predetermined ratio is a weight ratio or a volume ratio; The phosphor and encapsulating adhesive are mixed by mechanical stirring or centrifugal degassing to ensure that the phosphor is evenly dispersed in the encapsulating adhesive.

[0011] According to one aspect of the above technical solution, the at least three different dispensing amounts constitute an arithmetic gradient sequence, wherein the dispensing amount of the arithmetic gradient sequence is in the range of 1.5μL-2.0μL, and the interval between adjacent dispensing amounts is 0.1μL.

[0012] According to one aspect of the above technical solution, the preset conversion relationship is expressed as △λ=α×△K, where △λ is the wavelength difference, △K is the slope difference, and α is the conversion coefficient calibrated through previous experiments.

[0013] According to one aspect of the above technical solution, the calibration of the conversion factor α includes: Select N known wavelengths of the same type of phosphor whose wavelength values ​​cover the expected test range as calibration powder, where N is an integer not less than 3; Using the reference powder as a reference, the steps of glue preparation, dispensing, measurement and linear fitting are repeated for each calibration powder to obtain the slope difference values ​​△K1, △K2, ..., △K_N of each calibration powder relative to the reference powder. Calculate the known wavelength differences Δλ1, Δλ2, ..., Δλ_N between each calibration powder and the reference powder; A linear regression analysis is performed on the data point set (△K_i, △λ_i), and the slope of the resulting regression line is the conversion coefficient α.

[0014] According to one aspect of the above technical solution, for green phosphor, the calibration powder used when calibrating the conversion factor α has a known wavelength range covering 520nm-580nm; For red phosphors, the calibration powder used to calibrate the conversion factor α has a known wavelength range covering 600nm-620nm or 620nm-700nm.

[0015] According to one aspect of the above technical solution, based on the calibration results, the conversion relationship is specifically as follows: For green phosphors, in the wavelength range of 520nm-580nm, a 1° change in slope angle is equivalent to a 1nm change in wavelength. For red phosphors, a slope angle change of 0.5° is equivalent to a wavelength change of 1 nm in the wavelength range of 600 nm to 620 nm; or, in the wavelength range of 620 nm to 700 nm, a slope angle change of 0.2° is equivalent to a wavelength change of 1 nm.

[0016] Compared with existing technologies, the method for testing phosphor wavelengths based on the LED packaging process shown in this invention has the following advantages: This invention creatively embeds the phosphor wavelength testing process into the standard LED packaging process, effectively addressing the industry pain points mentioned in the background art, such as the high cost, complex operation, and inability to quickly apply dedicated testing equipment on the production floor. This method utilizes the high-precision dispensing equipment inherent in the packaging production line, creating a glue volume gradient and establishing a glue volume-wavelength linear model to transform complex absolute wavelength measurements into reliable slope comparisons. This not only significantly reduces testing costs, requiring only existing production line equipment, but also achieves seamless integration of testing operations with the production process, greatly improving the immediacy and convenience of phosphor incoming material verification and production process monitoring. Crucially, through the slope comparison model and preset conversion relationships, this method effectively eliminates random errors from single-point testing, ensuring the repeatability and accuracy of evaluation results, and providing packaging plants with a low-cost, high-efficiency, and highly reliable quality monitoring method. Attached Figure Description

[0017] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a flowchart illustrating the method for testing phosphor wavelength based on the LED packaging process in an embodiment of the present invention. Figure 2 This is a schematic diagram showing the wavelengths of the reference phosphor and the test phosphor in an embodiment of the present invention. Detailed Implementation

[0018] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Several embodiments of the invention are illustrated in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0019] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0021] Example 1 Please see Figures 1-2 The first embodiment of the present invention provides a method for testing phosphor wavelengths based on an LED packaging process, the method comprising: Step S10: Provide blue LED chips and fabricate them into semi-finished units via die bonding and wire bonding; Step S20: Use green and red phosphors of known wavelengths as reference powders and green and red phosphors of the wavelength to be tested as test powders, and mix them with encapsulating adhesive in the same predetermined ratio to prepare reference fluorescent adhesive and test fluorescent adhesive. Step S30: Apply the reference fluorescent adhesive and the fluorescent adhesive to be tested to multiple semi-finished product units with at least three different amounts of adhesive, and cure them to form test samples; Step S40: Illuminate the sample under constant current and measure the spectrum, and record the wavelength values ​​of the excitation peak of the phosphor in each sample. Step S50: Perform linear fitting with the amount of each fluorescent adhesive as the abscissa and the corresponding wavelength as the ordinate to obtain the wavelength-adhesive amount fitting line and slope of the reference powder and the test powder. Step S60: Calculate the wavelength of the phosphor to be tested using a preset conversion relationship based on the difference between the slope of the phosphor to be tested and the slope of the reference phosphor of the same color system.

[0022] In this embodiment, the steps of preparing the reference fluorescent adhesive and the test fluorescent adhesive by mixing green and red phosphors of known wavelengths as reference powders and green and red phosphors of the wavelength to be measured as test powders with encapsulating adhesive in the same predetermined ratio include: Green phosphor of known wavelength is selected as the first reference powder and red phosphor of known wavelength is selected as the second reference powder. They are mixed with encapsulating adhesive in a first predetermined ratio to prepare the first reference fluorescent adhesive and the second reference fluorescent adhesive. The green phosphor and the red phosphor of the wavelength to be measured are respectively mixed with the encapsulating adhesive in the first predetermined ratio to prepare the first fluorescent adhesive to be tested and the second fluorescent adhesive to be tested.

[0023] Furthermore, the steps of performing linear fitting with the amount of each fluorescent adhesive as the abscissa and the corresponding wavelength as the ordinate to obtain the wavelength-adhesive amount fitting line and slope between the reference powder and the test powder include: Linear fitting was performed with the amount of the first and second reference fluorescent adhesives as the abscissa and the corresponding wavelength as the ordinate, respectively, to obtain the first reference wavelength-adhesive amount fitting line and the second reference wavelength-adhesive amount fitting line, and the slopes Kreference green and Kreference red were calculated respectively. Linear fitting was performed with the amount of the first and second fluorescent adhesives to be tested as the abscissa and the corresponding wavelength as the ordinate, respectively, to obtain the first wavelength-adhesive amount fitting line and the second wavelength-adhesive amount fitting line, and the slopes K_tested green and K_tested red were calculated respectively.

[0024] In this embodiment, in the step of mixing phosphor and encapsulating adhesive, the same predetermined ratio is a weight ratio or a volume ratio; The phosphor and encapsulating adhesive are mixed by mechanical stirring or centrifugal degassing to ensure that the phosphor is evenly dispersed in the encapsulating adhesive.

[0025] The at least three different dispensing amounts constitute an arithmetic gradient sequence, wherein the dispensing amount of the arithmetic gradient sequence is in the range of 1.5 μL to 2.0 μL, and the interval between adjacent dispensing amounts is 0.1 μL.

[0026] In this embodiment, the preset conversion relationship is expressed as △λ=α×△K, where △λ is the wavelength difference, △K is the slope difference, and α is the conversion coefficient calibrated through previous experiments.

[0027] The calibration of the conversion factor α includes: Select N known wavelengths of the same type of phosphor whose wavelength values ​​cover the expected test range as calibration powder, where N is an integer not less than 3; Using the reference powder as a reference, the steps of glue preparation, dispensing, measurement and linear fitting are repeated for each calibration powder to obtain the slope difference values ​​△K1, △K2, ..., △K_N of each calibration powder relative to the reference powder. Calculate the known wavelength differences Δλ1, Δλ2, ..., Δλ_N between each calibration powder and the reference powder; A linear regression analysis is performed on the data point set (△K_i, △λ_i), and the slope of the resulting regression line is the conversion coefficient α.

[0028] In this embodiment, for the green phosphor, the calibration powder used to calibrate the conversion factor α has a known wavelength range covering 520nm-580nm; For red phosphors, the calibration powder used to calibrate the conversion factor α has a known wavelength range covering 600nm-620nm or 620nm-700nm.

[0029] Based on the calibration results, the conversion relationship is specifically as follows: For green phosphors, in the wavelength range of 520nm-580nm, a 1° change in slope angle is equivalent to a 1nm change in wavelength. For red phosphors, a slope angle change of 0.5° is equivalent to a wavelength change of 1 nm in the wavelength range of 600 nm to 620 nm; or, in the wavelength range of 620 nm to 700 nm, a slope angle change of 0.2° is equivalent to a wavelength change of 1 nm.

[0030] Experience shows that, under specific chip and testing conditions, the conversion factor α is approximately constant. For example, a 1° change in slope angle between 520nm and 580nm is approximately equivalent to a 1nm change in wavelength; a 0.5° change in slope angle between 600nm and 620nm is approximately equivalent to a 1nm change in wavelength; and a 0.2° change in slope angle between 620nm and 700nm is approximately equivalent to a 1nm change in wavelength.

[0031] A specific embodiment of the present invention is described below.

[0032] First, preparatory work was carried out before testing, selecting a blue LED chip with fixed specifications and a chip size of 1024 mil. 2 The main wavelength is 450nm±1nm, and the optical power level is 200mW. The blue LED chip is fabricated on the LED bracket using standard die bonding and wire bonding processes to form a series of semi-finished units ready for adhesive dispensing, ensuring that the initial conditions of all test samples are completely consistent.

[0033] The next step is the preparation of the fluorescent colloids. A green phosphor with a known wavelength of 520 nm was selected as the first reference powder, and a red phosphor with a known wavelength of 620 nm was selected as the second reference powder. Simultaneously, the green phosphor and red phosphor to be evaluated for their respective wavelengths were prepared. These two reference powders and the two test powders were mixed with the same epoxy encapsulating adhesive at the same weight ratio (e.g., 1:9), and uniformly dispersed using mechanical stirring or centrifugal degassing, thus obtaining the first reference fluorescent adhesive, the second reference fluorescent adhesive, the first test fluorescent adhesive, and the second test fluorescent adhesive, respectively. Furthermore, the mixing ratio and process of the reference powders and test powders of the same color system were ensured to eliminate the interference of irrelevant variables on the test results.

[0034] Then, the core gradient dispensing test stage begins. Using high-precision dispensing equipment, the four phosphor colloids are applied to the central light-emitting area of ​​the previously prepared semi-finished unit at multiple different dispensing volumes. For example, a gradient dispensing volume sequence with equal intervals from 1.5 μL to 2.0 μL and 0.1 μL can be set. After dispensing, the samples are placed in an oven and cured under the curing conditions of conventional LED packaging processes (e.g., curing at 150°C for 1 hour), ultimately forming multiple sets of LED samples available for testing.

[0035] After sample preparation, data acquisition is performed. All test samples are illuminated under a constant driving current (e.g., 20mA), and the spectrum of each sample is measured using an integrating sphere spectrometer or a spectrophotometer. The wavelength values ​​corresponding to the excitation peaks of the phosphors are then accurately recorded.

[0036] After obtaining the measured data, a mathematical model is established. The amount of the first and second reference fluorescent adhesives is plotted on the x-axis, and their corresponding measured wavelengths on the y-axis, respectively. A linear fit (usually using the least squares method) is performed to obtain two reference wavelength-adhesive amount fitting lines, and their slopes are calculated, denoted as Kreference green and Kreference red. This process is repeated for the first and second fluorescent adhesives to be tested, obtaining the target wavelength-adhesive amount fitting lines and their slopes Ktarget green and Ktarget red.

[0037] Finally, based on the difference between the slope of the phosphor to be tested and the slope of the reference phosphor of the same color system, the wavelength of the phosphor to be tested is calculated using a preset conversion relationship. This conversion relationship is expressed as Δλ = α × ΔK, where Δλ is the wavelength difference, ΔK is the slope difference, and α is the conversion coefficient calibrated through previous experiments.

[0038] The calibration method for the conversion factor α is as follows: Using multiple phosphors with known wavelengths covering the expected range (e.g., 520nm-580nm for green phosphors) as calibration powders, the above testing and fitting steps were repeated to obtain a series of slope differences ΔK and known wavelength differences Δλ. Linear regression analysis was then performed on the data points (ΔK_i, Δλ_i), and the slope of the regression line is the conversion coefficient α. Experience shows that, under specific conditions, for green phosphors, a 1° change in slope angle is approximately equivalent to a 1nm change in wavelength.

[0039] In summary, this invention successfully integrates phosphor wavelength testing into the standard LED packaging process, enabling low-cost, rapid, and reliable evaluation of phosphors using conventional equipment used in the LED packaging process. This greatly facilitates real-time quality control and incoming material inspection on the production floor.

[0040] This embodiment creatively embeds the phosphor wavelength testing process into the standard LED packaging process, effectively addressing the industry pain points mentioned in the background art, such as the high cost, complex operation, and inability to be quickly applied on the production floor with dedicated testing equipment. This method utilizes the high-precision dispensing equipment inherent in the packaging production line, creating a glue volume gradient and establishing a glue volume-wavelength linear model to transform complex absolute wavelength measurements into reliable slope comparisons. This not only significantly reduces testing costs, requiring only existing production line equipment, but also achieves seamless integration of testing operations with the production process, greatly improving the immediacy and convenience of phosphor incoming material verification and production process monitoring. Crucially, through the slope comparison model and preset conversion relationships, this method effectively eliminates random errors from single-point testing, ensuring the repeatability and accuracy of evaluation results, and providing packaging plants with a low-cost, high-efficiency, and highly reliable quality monitoring method.

[0041] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0042] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0043] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for testing phosphor wavelength based on LED packaging process, characterized in that, The method includes: We provide blue LED chips, which are then manufactured into semi-finished units via die bonding and wire bonding. Green and red phosphors of known wavelengths are used as reference powders, and green and red phosphors of the wavelength to be tested are used as test powders. They are mixed with encapsulating adhesive in the same predetermined ratio to prepare reference phosphor adhesive and test phosphor adhesive. The reference fluorescent adhesive and the fluorescent adhesive to be tested were applied to multiple semi-finished product units at at least three different amounts, and the samples were cured to form test samples. The sample was illuminated under constant current and the spectrum was measured. The wavelength values ​​of the excitation peak of the phosphor in each sample were recorded. Linear fitting was performed with the amount of each fluorescent adhesive as the abscissa and the corresponding wavelength as the ordinate to obtain the wavelength-adhesive amount fitting line and slope of the reference powder and the test powder. The wavelength of the phosphor to be tested is calculated using a preset conversion relationship based on the difference between the slope of the phosphor to be tested and the slope of the reference phosphor of the same color system.

2. The method for testing phosphor wavelength based on LED packaging process according to claim 1, characterized in that, The steps of preparing reference fluorescent adhesive and test fluorescent adhesive by mixing green and red phosphors of known wavelengths as reference powders and green and red phosphors of the wavelength to be measured as test powders with encapsulating adhesive in the same predetermined proportions include: Green phosphor of known wavelength is selected as the first reference powder and red phosphor of known wavelength is selected as the second reference powder. They are mixed with encapsulating adhesive in a first predetermined ratio to prepare the first reference fluorescent adhesive and the second reference fluorescent adhesive. The green phosphor and the red phosphor of the wavelength to be measured are respectively mixed with the encapsulating adhesive in the first predetermined ratio to prepare the first fluorescent adhesive to be tested and the second fluorescent adhesive to be tested.

3. The method for testing phosphor wavelength based on LED packaging process according to claim 1, characterized in that, The steps for performing linear fitting with the amount of each fluorescent adhesive as the abscissa and the corresponding wavelength as the ordinate to obtain the wavelength-adhesive amount fitting line and slope for the reference powder and the test powder include: Linear fitting was performed with the amount of the first and second reference fluorescent adhesives as the abscissa and the corresponding wavelength as the ordinate, respectively, to obtain the first reference wavelength-adhesive amount fitting line and the second reference wavelength-adhesive amount fitting line, and the slopes Kreference green and Kreference red were calculated respectively. Linear fitting was performed with the amount of the first and second fluorescent adhesives to be tested as the abscissa and the corresponding wavelength as the ordinate, respectively, to obtain the first wavelength-adhesive amount fitting line and the second wavelength-adhesive amount fitting line, and the slopes K_tested green and K_tested red were calculated respectively.

4. The method for testing phosphor wavelength based on LED packaging process according to claim 1, characterized in that, In the step of mixing phosphor and encapsulating adhesive, the same predetermined ratio is either a weight ratio or a volume ratio. The phosphor and encapsulating adhesive are mixed by mechanical stirring or centrifugal degassing to ensure that the phosphor is evenly dispersed in the encapsulating adhesive.

5. The method for testing phosphor wavelength based on LED packaging process according to claim 4, characterized in that, The at least three different dispensing amounts constitute an arithmetic gradient sequence, wherein the dispensing amount of the arithmetic gradient sequence is in the range of 1.5 μL to 2.0 μL, and the interval between adjacent dispensing amounts is 0.1 μL.

6. The method for testing phosphor wavelength based on LED packaging process according to claim 1, characterized in that, The preset conversion relationship is expressed as △λ=α×△K, where △λ is the wavelength difference, △K is the slope difference, and α is the conversion coefficient calibrated through previous experiments.

7. The method for testing phosphor wavelength based on LED packaging process according to claim 6, characterized in that, The calibration of the conversion factor α includes: Select N known wavelengths of the same type of phosphor whose wavelength values ​​cover the expected test range as calibration powder, where N is an integer not less than 3; Using the reference powder as a reference, the steps of glue preparation, dispensing, measurement and linear fitting are repeated for each calibration powder to obtain the slope difference values ​​△K1, △K2, ..., △K_N of each calibration powder relative to the reference powder. Calculate the known wavelength differences Δλ1, Δλ2, ..., Δλ_N between each calibration powder and the reference powder; A linear regression analysis is performed on the data point set (△K_i, △λ_i), and the slope of the resulting regression line is the conversion coefficient α.

8. The method for testing phosphor wavelength based on LED packaging process according to claim 7, characterized in that, For green phosphors, the calibration powder used to calibrate the conversion factor α has a known wavelength range of 520nm-580nm. For red phosphors, the calibration powder used to calibrate the conversion factor α has a known wavelength range covering 600nm-620nm or 620nm-700nm.

9. The method for testing phosphor wavelength based on LED packaging process according to claim 8, characterized in that, Based on the calibration results, the conversion relationship is as follows: For green phosphors, in the wavelength range of 520nm-580nm, a 1° change in slope angle is equivalent to a 1nm change in wavelength. For red phosphors, a slope angle change of 0.5° is equivalent to a wavelength change of 1 nm in the wavelength range of 600 nm to 620 nm; or, in the wavelength range of 620 nm to 700 nm, a slope angle change of 0.2° is equivalent to a wavelength change of 1 nm.

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