Device and method for testing mechanoluminescence efficiency

Abstract

The invention discloses a mechanoluminescence efficiency testing device and method, and the device comprises a mechanoluminescence film which is disposed on a photoelectric detector; the stress load applying device is used for applying a load to the mechanoluminescence film, so that the mechanoluminescence film is deformed and an optical signal is generated at a deformation position; the photoelectric detector is used for collecting optical signals generated by the mechanoluminescence film to obtain a series of optical image signals within stress action time; the shading film is used for shading the area outside the mechanoluminescence film on the photoelectric detector and reducing the influence of ambient light on the experiment; and the image processing equipment is used for converting the image signal obtained by the photoelectric detector into photon energy. The mechanoluminescence efficiency testing device and method provided by the invention are convenient, reliable and universal, fill the blank in the field of mechanoluminescence efficiency testing, and are suitable for further popularization and application.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of performance detection of mechanoluminescent materials, and particularly relates to a testing device and method for mechanoluminescent efficiency. BACKGROUND

[0002] Mechanoluminescent materials are a kind of advanced functional materials that can emit photons under the mechanical action of stretching, bending, friction, ultrasonic and the like. The mechanoluminescent materials can produce optical response to the input mechanical action without providing a light source or a power supply, and have excellent sensing reliability and visual convenience, etc. The mechanoluminescent materials have great application potential in the fields of structural damage detection, wearable devices, biomechanical engineering, optical information anti-counterfeiting and the like. Although a large number of mechanoluminescent material systems have been reported at present, how to objectively evaluate the performance of the mechanoluminescent materials is a prominent problem in material development and application research. This is mainly due to the lack of standardized testing methods in the field of mechanoluminescent material research, especially for the characterization of mechanoluminescent intensity. The test results obtained by using different testing methods or using different devices are different, which will lead to the fact that the luminescent intensities of different materials cannot be directly compared, and this is extremely unfavorable for material performance evaluation and new material development.

[0003] The fluorescence quantum efficiency (or photoluminescent efficiency) is an important indicator for measuring the luminescent intensity of a fluorescent material (or photoluminescent material), and is usually estimated by:

[0004]

[0005] or

[0006] wherein η E and η I are the external quantum efficiency and the internal quantum efficiency, respectively, and N E , N I and N A are the number of emitted photons, the number of incident photons and the number of absorbed photons, respectively. It is generally considered that the luminescent efficiency is one of the inherent properties of a material, and is less affected by the testing conditions (such as light source and detector), and thus is widely used for performance evaluation and material screening of fluorescent materials. In the fluorescence quantum efficiency test, an integrating sphere and a photodetector (such as a photomultiplier tube PMT or a charge-coupled device CCD) are necessary device components. The sample is placed at the center or the bottom of the integrating sphere, and the number of emitted photons, the number of incident photons and the number of absorbed photons are calculated by calibrating the photodetector through the integrating sphere.

[0007] The mechanoluminescent efficiency can be defined by using a similar principle to the above-mentioned fluorescence quantum efficiency (photoluminescent efficiency), that is:

[0008]

[0009] wherein E P is the energy of the emitted photons, E M is the energy of the input mechanical action. If the force-induced luminescence efficiency is accurately measured, it can effectively solve the problem that the luminescence intensities of different materials are difficult to compare. However, so far, there is no report on the force-induced luminescence efficiency testing method and testing device. This is because in the above definition of force-induced luminescence efficiency, E P and E M belong to different types of energy, and the formulas (1) and (2) have essential differences in testing method and testing device. The force-induced luminescence efficiency cannot be tested by using the existing photoluminescence efficiency testing device and testing method. SUMMARY

[0010] In view of the above problems, the present application provides a testing device and method for force-induced luminescence efficiency.

[0011] To achieve the above object, the present application is implemented by the following technical solutions:

[0012] The present application provides a testing device for force-induced luminescence efficiency, comprising:

[0013] a force-induced luminescence film arranged on a photodetector;

[0014] a stress load applying device for applying a load to the force-induced luminescence film, so that the force-induced luminescence film is deformed and generates a light signal at the deformed position;

[0015] a photodetector for collecting the light signal generated by the force-induced luminescence film to obtain a series of optical image signals within a stress action time;

[0016] a light shielding film for shielding the area outside the force-induced luminescence film on the photodetector to reduce the influence of ambient light on the experiment;

[0017] an image processing device for converting the image signal obtained by the photodetector into photon energy.

[0018] As a possible implementation, further, the stress load applying device is a falling ball device, which can drop a ball at a fixed position on the upper end of the photodetector; the distance between the ball and the photodetector in the vertical direction is 5-25 cm.

[0019] As a possible implementation, further, the force-induced luminescence film is composed of an organic polymer material and a force-induced luminescence material, and the mass ratio of the organic polymer material to the force-induced luminescence material when they are compounded is 1:1-2:1; the thickness of the force-induced luminescence film is 0.1-0.8 mm.

[0020] As a possible implementation, further, the force luminescent material is selected from at least one of ZnS:Mn, ZnS:Cu@Al2O3, SrAl2O4:Eu,Dy, ZnS / CaZnOS:Mn, LiNbO3:Pr, NaNbO3:Pr, CaZnOS:Mn, CaZnOS:Ln, SrZnOS:Mn, SrZn2S2O:Ln, MgF2:Mn, BaSi2O2N2:Eu,Dy, Ba5(PO4)3Cl:Eu, Ca2MgSi2O7:Eu, beta-SiAlON:Eu, wherein Ln is Tb, Eu, Dy, Ho, Er, Sm, Pr, Nd, Tm, Ce, Gd or Yb.

[0021] As a preferred implementation, preferably, the force luminescent material is selected from ZnS:Cu@Al2O3.

[0022] As a possible implementation, further, the organic polymer material is selected from epoxy resin, polydimethylsiloxane, polymethyl methacrylate or Ecoflex.

[0023] As a preferred implementation, preferably, the organic polymer material is selected from polydimethylsiloxane.

[0024] As a possible implementation, further, the photoelectric detector is a CMOS sensor, which can accurately capture the falling position of the small ball and record the luminescent gray scale information generated by the force luminescent film; the force luminescent film is adsorbed on the CMOS sensor by electrostatic force, and the blank area of the CMOS sensor is covered with a light shielding film to reduce the interference of environmental light on the experiment.

[0025] The application also provides a force luminescent efficiency testing method, which applies the force luminescent efficiency testing device.

[0026] S1: a force luminescent composite film is formed by compounding a force luminescent material to be tested and an organic polymer;

[0027] S2: the force luminescent composite film is tightly adsorbed on the CMOS sensor by electrostatic force, and the area of the CMOS sensor other than the force luminescent composite film is covered by a light shielding film;

[0028] S3: a small ball is dropped from a certain height above the CMOS sensor by using a ball dropping device, so that the force luminescent film is elastically deformed and then emits light;

[0029] S4: The CMOS sensor accurately records the ball drop position and obtains a series of image signals within the stress action time, and the luminescent series of image signals are converted into photon energy by using the image processing device and the structure information of the CMOS detector, and then the efficiency of the mechanoluminescence is obtained.

[0030] As a possible implementation, further, S4 specifically comprises the following steps:

[0031] S4.1: The CMOS sensor obtains the ball drop position, the total number of pixel points corresponding to the ball drop position, and the average gray scale of each pixel point in the frame before the light signal generated by the ball drop position and the average gray scale of each pixel point in the 10 frames after the ball drop;

[0032] S4.2: According to the average gray scale of each pixel point in the frame before the light signal generated by the ball drop position and the average gray scale of each pixel point in the 10 frames after the ball drop obtained in step S4.1, the total value of the gray scale information of each pixel point generated by the luminescence of the mechanoluminescence film after the ball drop is calculated;

[0033] S4.3: According to the total value of the gray scale information of each pixel point generated by the luminescence of the mechanoluminescence film after the ball drop, the total number of pixel points corresponding to the ball drop position, and the average increased number of electrons corresponding to each gray scale increase of the CMOS sensor, the total number of electrons generated after the ball drop is calculated;

[0034] S4.4: According to the pixel filling rate of the CMOS sensor and the average photoelectric efficiency of the CMOS sensor, the total number of electrons generated after the ball drop obtained in step S4.3 is corrected, and the corrected total number of electrons is multiplied by 2 to obtain the actual total number of electrons;

[0035] S4.5: According to the energy carried by each electron and the actual total number of electrons obtained in step S4.4, the total light energy generated in the ball drop process is obtained;

[0036] S4.6: The gravitational work when the ball drops is calculated, and the mechanoluminescence efficiency is obtained according to the gravitational work when the ball drops and the total light energy generated in the ball drop process.

[0037] The beneficial effects of the present application are as follows:

[0038] The present application provides a convenient, reliable and universal mechanoluminescence efficiency testing device and method, which fills the gap in the field of mechanoluminescence efficiency testing. The mechanoluminescence efficiency testing device has the advantages of simple structure and convenient use. In addition, the testing steps of the mechanoluminescence efficiency testing method provided by the present application are simple and have good testing effect, and are suitable for further popularization and application. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0040] Figure 1 Schematic diagram of the test device for force-induced luminescence efficiency.

[0041] Figure 2 Images obtained by the CMOS sensor before and after the ball falls; wherein the left image is the image obtained by the CMOS sensor before the ball falls, and the right image is the image obtained by the CMOS sensor after the ball falls.

[0042] The label names in the drawings are as follows:

[0043] Photoelectric detector-11; light shielding film-12; force-induced luminescence film-13; ball falling device-14. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the following will combine the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0045] Referring to the drawings shown in the Figure 1 The present embodiment provides a force-induced luminescence efficiency test device, which mainly comprises: a photoelectric detector 11, a light shielding film 12, a force-induced luminescence film 13, a stress load applying device and an image processing device.

[0046] The force-induced luminescence film 13 is a thin film formed by compounding a force-induced luminescence material sample and an organic polymer material. The force-induced luminescence film 13 will emit light when subjected to mechanical force, and the light emission intensity is positively correlated with the size of the mechanical force. When the applied mechanical force disappears, the force-induced luminescence composite film can restore to the original state. The force-induced luminescence film 13 is tightly adsorbed on the CMOS sensor by electrostatic force.

[0047] The thickness of the force-induced luminescence film 13 is 0.1mm-0.8mm. In the present embodiment, the thickness of the force-induced luminescence film 13 is 0.3mm, and the length and width are 4cm and 4cm respectively. In addition, in other embodiments, the shape of the force-induced luminescence film 13 is not limited to square, but can also be rectangular, circular, elliptical or other irregular shapes, etc.

[0048] In particular, the force-induced luminescent material includes at least one of ZnS:Mn, ZnS:Cu@Al2O3, LiNbO3:Pr, SrAl2O4:Eu, Dy, CaZnOS:Mn, ZnS / CaZnOS:Mn, NaNbO3:Pr, SrZnOS:Mn, SrZn2S2O:Ln, β-SiAlON:Eu, BaSi2O2N2:Eu, Dy, MgF2:Mn, Ba5(PO4)3Cl:Eu, Ca2MgSi2O7:Eu, and CaZnOS:Ln, where Ln is Tb, Eu, Dy, Ho, Er, Sm, Pr, Nd, Tm, Ce, Gd, or Yb. In this embodiment, the force-induced luminescent material is ZnS:Cu@Al2O3. ZnS:Cu@Al2O3 has good piezoelectricity and is also an electroluminescent material. The force-induced luminescent material can be directly purchased or obtained by a high-temperature solid-phase method.

[0049] In particular, the organic polymer material is selected from polydimethylsiloxane (PDMS), epoxy resin (ER), polymethyl methacrylate (PMMA), or Ecoflex, etc. In this embodiment, the organic polymer material is polydimethylsiloxane (PDMS). Polydimethylsiloxane (PMDS) has excellent flexibility and elasticity, so that it will not be damaged when subjected to a large mechanical deformation, and has good transparency. The mass ratio of polydimethylsiloxane (PDMS) to the force-induced luminescent material is 1:1 to 2:1.

[0050] After the ZnS:Cu@Al2O3 is compounded with polydimethylsiloxane (PDMS) in this embodiment, a bright green light emission can be generated when a mechanical force is applied, and the response to the mechanical force is very sensitive.

[0051] In one embodiment, the preparation process of the force-induced luminescent composite film is as follows: polydimethylsiloxane (PDMS) precursor and curing agent with a mass ratio of 10:1 are mixed in a beaker. ZnS:Cu@Al2O3 force-induced luminescent powder and polydimethylsiloxane are added to the mixture in a mass ratio of 2:1, and stirred at room temperature for 5 minutes. The beaker is transferred to a vacuum drying box for 10 minutes to remove bubbles in the mixture. The bubble-free fluorescent powder mixture is uniformly introduced into a 4cm*4cm acrylic mold, and the mold is transferred to an 80°C oven for curing for 1 hour. After natural cooling to room temperature, a force-induced luminescent film with a thickness of 0.3mm is obtained. In other embodiments, the preparation method of the force-induced luminescent composite film is not limited to the above method.

[0052] The photoelectric detector 11 is used to capture the light signal generated by the mechanoluminescent film 13 when subjected to mechanical force, and obtain a series of optical image signals within the stress action time. In this embodiment, the photoelectric detector 11 is a CMOS sensor. It can be understood that in other examples, the photoelectric detector 11 is not limited to a CMOS sensor, but can also be a CCD sensor, a photomultiplier tube (PMT), etc. The photoelectric detector 11 can accurately capture the light signal generated by the mechanoluminescent film 13 when subjected to mechanical stimulation and accurately capture the falling position of the small ball.

[0053] In one embodiment, the surface of the COMS sensor where the mechanoluminescent film needs to be adsorbed is cleaned with alcohol, and the mechanoluminescent composite film is adsorbed on the surface of the CMOS sensor by electrostatic force.

[0054] In this embodiment, the sensing area of the CMOS sensor is 15 cm*15 cm, and the gray value range is 0-65535. Except for the position of the mechanoluminescent film 13, other areas are covered by the light shielding film 12 (as shown in Figure 1 ).

[0055] The light shielding film 12 is used to shield the area outside the mechanoluminescent film 13 on the photoelectric detector 11, thereby reducing the influence of environmental light on the experiment.

[0056] The stress load applying device selects a falling ball device 14 for controlling the mechanical force applied to the mechanoluminescent film 13. The size of the mechanical force can be controlled by the height of the small ball (the material of the small ball can be steel, glass, or zirconia) and the size of the small ball, and the falling ball device 14 is located directly above the mechanoluminescent film 13.

[0057] Specifically, the falling ball device 14 is arranged directly above the mechanoluminescent composite film, and the distance between the small ball and the mechanoluminescent film 13 in the vertical direction is 5-25 cm. Within the above distance range, the CMOS sensor can preferably capture a better image, and at the same time, the CMOS sensor will not be damaged. In one embodiment, the distance between the small ball and the mechanoluminescent film 13 in the vertical direction is 8 cm.

[0058] An image processing device is electrically connected to the photoelectric detector 11 and is used for subsequent image data processing. The image processing device converts the image signal obtained by the photoelectric detector 11 into photon energy. In this example, the image processing device is a computer, and the photoelectric detector and the image processing device are connected through a USB. In other embodiments, the connection mode can also be other commonly used communication connection modes.

[0059] The embodiment also provides a mechanoluminescent efficiency testing method, which applies the above-mentioned mechanoluminescent efficiency testing device. The mechanoluminescent efficiency testing method comprises the following steps:

[0060] S1: a piezoluminescent material to be tested is compounded with an organic polymer to form a piezoluminescent composite film;

[0061] S2: the piezoluminescent composite film is tightly adsorbed on a CMOS sensor by electrostatic force, and an area of the CMOS sensor other than the piezoluminescent composite film is covered by a light shielding film;

[0062] S3: a small ball is dropped from a certain height above the CMOS sensor by using a ball dropping device, so that the piezoluminescent film is elastically deformed and emits light;

[0063] S4: the CMOS sensor accurately records the position of the small ball and obtains a series of image signals within the stress action time, and the image processing device and the structural information of the CMOS detector are used to convert the series of image signals into photon energy, and then the piezoluminescent efficiency is obtained; the specific steps are as follows:

[0064] S4.1: the position of the small ball, the total number of pixel points corresponding to the position of the small ball, and the average gray scale of each pixel point in the frame before the light signal generated by the position of the small ball and the average gray scale of each pixel point in the 10 frames after the small ball is dropped are obtained by the CMOS sensor;

[0065] S4.2: according to the average gray scale of each pixel point in the frame before the light signal generated by the position of the small ball and the average gray scale of each pixel point in the 10 frames after the small ball is dropped obtained in step S4.1, the total value of the gray scale information of each pixel point generated by the light emission of the piezoluminescent film after the small ball is dropped is calculated;

[0066] S4.3: according to the total value of the gray scale information of each pixel point generated by the light emission of the piezoluminescent film after the small ball is dropped, the total number of pixel points corresponding to the position of the small ball, and the average number of electrons increased corresponding to each gray scale increase of the CMOS sensor, the total number of electrons generated after the small ball is dropped is calculated;

[0067] S4.4: according to the pixel filling rate of the CMOS sensor and the average photoelectric efficiency of the CMOS sensor, the total number of electrons generated after the small ball is dropped obtained in step S4.3 is corrected, and the corrected total number of electrons is multiplied by 2 to obtain the actual total number of electrons;

[0068] S4.5: according to the energy carried by each electron and the actual total number of electrons obtained in step S4.4, the total light energy generated in the ball dropping process is obtained;

[0069] S4.6: the work done by gravity when the small ball is dropped is calculated, and the piezoluminescent efficiency is obtained according to the work done by gravity when the small ball is dropped and the total light energy generated in the ball dropping process.

[0070] The application will be further described in detail below with reference to examples, but the embodiments of the application are not limited thereto:

[0071] An iron ball with a mass of 518 mg is selected and dropped vertically 8 cm above the mechanoluminescence composite film.

[0072] The position of the small ball and the mechanoluminescence information of the mechanoluminescence composite film when the small ball is dropped can be obtained by the CMOS sensor (such as Figure 2 The average gray value of each pixel point in the previous frame before the light signal is generated at the position where the small ball is dropped is 93.97, and the average gray value of each pixel point in the 10 frames after the small ball is dropped is 3351.43, 242.03, 167.46, 140.35, 127.77, 119.42, 115.28, 111.87, 109.66, and 107.16.

[0073] Each gray value of the CMOS sensor corresponds to an average increase of 27.5 electrons.

[0074] The total value of the gray information of each pixel point generated by the mechanoluminescence film after the small ball is dropped is: 3351.43+242.03+167.46+140.35+127.77+119.42+115.28+111.87+109.66+107.16-93.97*10=3652.73.

[0075] The number of electrons generated by each pixel point after the small ball is dropped is: 3652.73*27.5=100450.075.

[0076] The total number of pixel points that emit light after the small ball is dropped is: 33*32=1056.

[0077] The total number of electrons generated after the small ball is dropped is: 1056*100450.075=106075279.2.

[0078] The pixel filling rate of the CMOS sensor is 80%, so the total number of electrons is: 106075279.2 / 80%=132594099.

[0079] The average photoelectric efficiency of the CMOS sensor is 75%, so the total number of electrons received by the CMOS sensor is: 132594099 / 75%=176792132.

[0080] The CMOS sensor can only monitor the light emission information of the lower surface of the mechanoluminescence composite film. We believe that the number of photons emitted from the upper and lower surfaces of the mechanoluminescence composite film during the ball drop process is consistent, so the actual total number of electrons is: 176792132 / 50%=353584264.

[0081] Each electron carries an energy of 1.6*10 -19 J, so the total light energy generated during the falling ball process is: 353584264*1.6*10 -19 =5.65734822.4*10 -11 J.

[0082] The gravity work of the small ball when falling is: 518*10 -6 *8*10 -2 *9.8=4.06112*10 -4 J.

[0083] The force-induced luminescence efficiency is: 5.65734822.4*10 -11 / 4.06112*10 -4 =1.3931*10 -7 .

[0084] The above examples are only used to illustrate the technical solutions of the present application, and not to limit it; although the present application has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent substitutions for part of the technical features; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A device for testing the efficiency of electroluminescence, characterized in that: include: A mechanoluminescent film is provided on a photodetector; A stress load applying device applies a load to the mechanoluminescent film to deform the film and generate a light signal at the deformation location; A photoelectric detector is used to collect the light signal generated by the mechanoluminescent film and obtain a series of optical image signals during the stress action time; A light-shielding film is used to shield the area outside the electroluminescent film on the photodetector to reduce the impact of ambient light on the experiment; Image processing equipment is used to convert the image signal obtained by the photodetector into photon energy.

2. The device for testing the mechanoluminescence efficiency according to claim 1, wherein: The stress load applying device is a ball dropping device, which can drop a small ball at a fixed position on the upper end of the photoelectric detector; the distance between the small ball and the photoelectric detector in the vertical direction is 5 to 25 cm.

3. The device for testing the mechanoluminescence efficiency according to claim 2, wherein: The mechanoluminescent film is formed by compounding an organic polymer material and a mechanoluminescent material, wherein the mass ratio of the organic polymer material to the mechanoluminescent material when compounded is 1:1 to 2:1; and the thickness of the mechanoluminescent film is 0.1 mm to 0.8 mm.

4. The device for testing the mechanoluminescence efficiency according to claim 3, wherein: The mechanoluminescent material is selected from at least one of ZnS:Mn, ZnS:Cu@Al2O3, SrAl2O4:Eu,Dy, ZnS / CaZnOS:Mn, LiNbO3:Pr, NaNbO3:Pr, CaZnOS:Mn, CaZnOS:Ln, SrZnOS:Mn, SrZn2S2O:Ln, MgF2:Mn, BaSi2O2N2:Eu,Dy, Ba5(PO4)3Cl:Eu, Ca2MgSi2O7:Eu, and β-SiAlON:Eu, wherein Ln is Tb, Eu, Dy, Ho, Er, Sm, Pr, Nd, Tm, Ce, Gd, or Yb.

5. The device for testing the mechanoluminescence efficiency according to claim 3, wherein: The mechanoluminescent material is ZnS:Cu@Al2O3.

6. The device for testing the mechanoluminescence efficiency according to claim 3, wherein: The organic polymer material is selected from epoxy resin, polydimethylsiloxane, polymethyl methacrylate or Ecoflex.

7. The device for testing the mechanoluminescence efficiency according to claim 3, wherein: The organic polymer material is polydimethylsiloxane.

8. The device for testing the mechanoluminescence efficiency according to claim 2, wherein: The photodetector is a CMOS sensor that can accurately capture the falling position of the ball and record the luminous grayscale information generated by the mesoluminescent film; the mesoluminescent film is adsorbed on the CMOS sensor by electrostatic force, and the blank area of ​​the CMOS sensor is covered with a light-shielding film to reduce the interference of ambient light on the experiment.

9. A method for testing the efficiency of mechanoluminescence, characterized in that: The device for testing the mechanoluminescence efficiency according to any one of claims 2 to 8 is used, and the method for testing the mechanoluminescence efficiency comprises the following steps: S1: Compounding the mechanoluminescent material to be tested with an organic polymer to form a mechanoluminescent composite film; S2: It is tightly adsorbed on the CMOS sensor through electrostatic force, and the area of ​​the CMOS sensor except the electroluminescent composite film is covered by a light-shielding film; S3: Using a ball drop device, a small ball is dropped at a certain height above the CMOS sensor, causing the mechanoluminescent film to undergo elastic deformation and emit light; S4: The CMOS sensor accurately records the falling position of the ball and obtains a series of image signals during the stress action time. The image processing equipment and the structural information of the CMOS detector itself are used to convert the series of luminescence image signals into photon energy, thereby obtaining the efficiency of mechanoluminescence.

10. The method for testing the mechanoluminescence efficiency according to claim 9, wherein: S4 specifically includes the following steps: S4.1: Using the CMOS sensor, obtain the ball's drop position, the total number of pixels corresponding to the ball's drop position, the average grayscale of each pixel in the frame before the ball's drop position generates a light signal, and the average grayscale of each pixel in the 10 frames after the ball's drop position. S4.2: Calculate the total grayscale information of each pixel generated by the electroluminescent film after the ball falls, based on the average grayscale of each pixel in the frame before the light signal is generated at the ball's falling position obtained in step S4.1 and the average grayscale of each pixel in the 10 frames after the ball falls; S4.3: Calculate the total number of electrons generated by the falling ball based on the total grayscale information of each pixel generated by the electroluminescent film after the ball falls, the total number of pixels corresponding to the position where the ball falls, and the average number of electrons increased per grayscale increase on the CMOS sensor. S4.4: Correct the total number of electrons generated by the falling ball obtained in step S4.3 based on the pixel fill rate and the average photoelectric efficiency of the CMOS sensor, and multiply the corrected total number of electrons by 2 to obtain the actual total number of electrons; S4.5: Based on the energy of each electron and the actual total number of electrons obtained in step S4.4, calculate the total light energy generated during the falling ball process; S4.6: Calculate the work done by gravity as the ball falls. Based on the work done by gravity as the ball falls and the total light energy generated during the falling process, calculate the luminous efficiency.

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