Apparatus and method for detecting reaction-emissive nano- or microparticles

Abstract

An apparatus for detecting reactive luminescent particles embedded in a substrate or surface, comprising: an infrared or ultraviolet illumination device for illuminating the luminescent particles, a near-infrared photodiode sensor for capturing the near-infrared response of the illuminated luminescent particles, a darkroom for placement over the substrate or surface, a logarithmic amplifier for amplifying and linearizing the response signal captured by the photodiode sensor, and an electronic data processor configured to detect the reactive luminescent particles, the detection being performed by performing the steps of illuminating the substrate or surface with the illumination device, obtaining the amplified and linearized signal captured by the photodiode sensor, and detecting the presence of the luminescent particles on the substrate or surface from the linearized decay of the obtained signal, the apparatus comprising another near-infrared photodiode sensor, another logarithmic amplifier, and a differentiator for obtaining the difference between the signals received and amplified by each photodiode sensor.

Description

Technical Field

[0001] The present disclosure relates to an apparatus and method for detecting reaction-emissive particles embedded in a substrate or surface. The apparatus includes an infrared irradiation device or an ultraviolet irradiation device for illuminating the emissive particles, a near-infrared photodiode sensor for capturing the near-infrared response of the illuminated emissive particles, a darkroom disposed on the substrate or surface and equipped with the irradiation device and the photodiode sensor therein, a logarithmic amplifier for amplifying and linearizing the signal captured by the photodiode sensor, and an electronic data processor configured to detect reaction-emissive particles. The detection is performed by performing the steps of illuminating the substrate or surface with the irradiation device, acquiring the amplified and linearized signal captured by the photodiode sensor, and detecting the presence of emissive particles on the substrate or surface from the linearized attenuation of the acquired signal.

Background Art

[0002] Small LNPs (Luminescent Nano-particles) of 5 microns or less react when illuminated with an infrared light source. This reaction is reflected energy at different wavelengths and is typically observed and examined using a spectrometer reader. These LNPs are usually mixed with various materials referred to as "substrates" and are used in many applications, i.e., as part of anti-counterfeiting solutions.

[0003] Examples of well-known anti-counterfeiting solutions using this type of solution and being superior to other technologies, banknotes utilize IR ink characteristics. The amount of LNP used is very small, and thus its detection is an extremely difficult task and is usually only possible under a research facility and / or a controlled environment. The motivation of the present invention is to create a device for material evaluation that gives the user the opportunity to detect the presence of LNP, perform identification and quantification at extremely low concentrations, and verify its authenticity. The concentration can be reduced to 10 ppm (or less), most of the light is absorbed by the substrate material, making it extremely difficult to detect LNP, and it can be within a dark substrate such that other devices fail due to insufficient sensitivity.

[0004] Patent Document 1 (International Publication No. WO1989 / 008224) discloses a linear coaxial lens having an elongated and thin cylindrical phosphorescent layer and a pair of collinear and coaxial optical waveguides sandwiching the thin cylindrical phosphorescent layer therebetween, and light incident along the length of the cylindrical phosphorescent layer induces the conservation of the radiant energy of the light and the emission of radiation in both directions of the optical waveguide of different wavelengths from the light incident on the cylindrical phosphorescent layer. Each optical waveguide has a fluorescent substance dispersed therein to absorb the radiation generated from the phosphorescent layer that re-emits the absorbed radiation, affect the internal scattering of the radiation in each waveguide, and capture it within the waveguide core. At least one end of the collinear and coaxial waveguide pair is adapted to emit light of different wavelengths, and the ends can be arranged in various patterns and / or can have diffusers or mirrors associated with the ends.

[0005] These facts are disclosed to explain the technical problems addressed by the present disclosure.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] The present disclosure aims to detect various infrared (IR) or ultraviolet (UV) luminescent nanoparticles (LNP) that react when receiving energy having a wavelength near 940 nm and send back energy in a wavelength band longer than 980 nm. Under laboratory conditions, isolated LNP at high concentrations (higher than 400 ppm) can be detected and recognized very easily. To reduce the cost of using LNP, it is desirable to reduce the concentration to 10 ppm while maintaining the full ability to detect and recognize. One of the motivations for the embodiments of the present invention is to have a portable and easy-to-handle small device with most of the features found in laboratory equipment.

[0008] In actual applications, the fact that the LNP is covered on the surface or embedded in the substrate adds new challenges to detection and recognition. Furthermore, the color of the substrate also hinders detection and limits the use of LNP to unsustainable levels. Black and dark colors are the worst cases where most of the light emission from the LNP is absorbed by the substrate. One way to solve this effect is to increase the intensity of the incident light and also increase the sensitivity of the optical sensor.

Means for Solving the Problems

[0009] Embodiments are disclosed that aim at a small portable enclosure with a bottom slit that allows light to pass through into a cavity where a light emitter and an optical sensor are disposed inside. The arrangement of the light emitter and the optical sensor is done in such a way as to reduce losses and have the maximum incident energy on the observed surface or substrate. The use of surface mount technology (SMT) devices for the light emitter and the optical sensor, LED and photodiode respectively, simplifies the implementation, which is because alignment is possible only by using the remaining two-dimensional directions after reducing the degrees of freedom in one-dimensional directions.

[0010] In one embodiment, the intensity of the light of the IR irradiation device or the UV irradiation device is controlled by a driving device based on a controlled constant current power supply.

[0011] In one embodiment, the device adjusts the intensity of the light for a given substrate by changing the DAC value.

[0012] In one embodiment, all the independent signals digitized from all the photodiodes can be combined, and this combination is a mathematical operation of digital signals, namely, addition, subtraction, integration, or a combination thereof.

[0013] In one embodiment, these mathematical operations are used for the identification and quantification of the reactive luminescent nanoparticles.

[0014] In one embodiment, an independent logarithmic amplifier circuit and a second-stage linear amplification are used in all the photodiodes.

[0015] In one embodiment, these additional second-stage amplifications are connected to independent ADC input channels.

[0016] In one embodiment, these additional second-stage amplifications are used for the identification and quantification of extremely low concentrations of reactive luminescent nanoparticles.

[0017] In one embodiment, the substrate is a fabric, leather, wood, paper, plastic, metal, or a combination thereof.

[0018] In one embodiment, one or more IR irradiation devices are LED-based IR irradiation devices or laser-based IR irradiation devices.

[0019] In one embodiment, one or more UV irradiation devices are LED-based UV irradiation devices or laser-based UV irradiation devices.

[0020] An embodiment of an apparatus for detecting reaction-emissive nano- or microparticles embedded in a substrate or on a surface is disclosed. The apparatus includes an infrared irradiation device or an ultraviolet irradiation device for illuminating the emissive particles, a near-infrared photodiode sensor for capturing the near-infrared response of the illuminated emissive particles, a darkroom disposed on the substrate or surface and equipped with the irradiation device and the photodiode sensor therein, a logarithmic amplifier for amplifying and linearizing the response signal captured by the photodiode sensor, and an electronic data processor configured to detect the reaction-emissive particles. The detection is performed by executing steps of illuminating the substrate or surface with the irradiation device, acquiring the signal captured, amplified, and linearized by the photodiode sensor, and detecting the presence of the emissive particles on the substrate or surface from the linearized attenuation of the acquired signal. The apparatus comprises the electronic data processor.

[0021] The darkroom is useful for creating a space where particles emit light when subjected to IR or UV irradiation.

[0022] In an embodiment, the apparatus includes another near-infrared photodiode sensor having a spectral sensitivity response different from that of the first photodiode sensor, another logarithmic amplifier for amplifying and linearizing the signal received by the other photodiode sensor, and a differentiator for obtaining the difference between the signals received and amplified by each photodiode sensor.

[0023] In an embodiment, the electronic data processor is configured to detect a peak exceeding a predetermined threshold in the time-domain signal of the difference.

[0024] In an embodiment, the electronic data processor is configured to distinguish between emissive particles having spectral responses different from that of the detected peak.

[0025] In one embodiment, the apparatus comprises a linear amplifier for further amplifying the signal captured by each photodiode sensor and amplified and linearized.

[0026] In one embodiment, the luminescent particles are responsive to wavelengths in the range of 750 to 2500 nm, particularly 750 to 1100 nm.

[0027] In one embodiment, the IR irradiation device is an LED-based IR irradiation device or a laser-based IR irradiation device.

[0028] In one embodiment, the UV irradiation device is an LED-based UV irradiation device or a laser-based UV irradiation device.

[0029] In one embodiment, the substrate is a fabric substrate, a paper substrate, a plastic substrate, a metal substrate, a cork substrate, a wood substrate, a leather substrate, a fur substrate, or a combination thereof.

[0030] In one embodiment, the logarithmic amplifier is an OP-AMP logarithmic amplifier.

[0031] In one embodiment, the reactive luminescent nano- or microparticles are La 3+ 、Ce 3+ 、Pr 3+ 、Nd 3+ 、Pm 3+ 、Sm 3+ 、Eu 3+ 、Gd 3+ 、Tb 3+ 、Dy 3+ 、Ho 3+ 、Er 3+ 、Tm 3+ 、Yb 3+ 、Lu 3+ 、or have a core of a rare earth ceramic material selected from the group of combinations thereof.

[0032] In one embodiment, the reactive luminescent nano- or microparticles have a particle size in the range of 10 nm to 25 μm, particularly 20 nm to 20 μm.

[0033] Furthermore, a computer-based method for detecting reaction-emissive nano- or microparticles embedded in a substrate or surface is disclosed. The method includes steps of irradiating the substrate or surface with an infrared or ultraviolet irradiator by an electronic data processor to illuminate the emissive particles; capturing a near-infrared response of the illuminated emissive nanoparticles with a near-infrared photodiode sensor, wherein the irradiator and the photodiode sensor are provided inside a darkroom disposed on the substrate or surface; amplifying and linearizing a response signal captured by the photodiode sensor with a logarithmic amplifier; acquiring the signal captured, amplified, and linearized by the photodiode sensor; and detecting the presence of the emissive particles on the substrate or surface from the linearized attenuation of the acquired signal.

[0034] In one embodiment, the method further includes steps of amplifying and linearizing a signal captured by another near-infrared photodiode sensor having a spectral sensitivity response different from that of the first photodiode sensor with another logarithmic amplifier, and obtaining a difference between signals received and amplified by each photodiode sensor with a differentiator.

[0035] In one embodiment, the method further includes a step of detecting a peak exceeding a predetermined threshold in a time-domain signal of the difference.

[0036] In one embodiment, the method further includes a step of distinguishing between emissive particles having spectral responses different from that of the detected peak.

[0037] In one embodiment, the emissive nanoparticles can exhibit reactivity to wavelengths of 750 to 2500 nm, particularly 750 to 1100 nm.

[0038] In one embodiment, the method comprises a substrate that can be a fabric substrate, a paper substrate, a plastic substrate, a metal substrate, a cork substrate, a wood substrate, a leather substrate, a fur substrate, or a combination thereof.

[0039] In one embodiment, the method is La 3+ , Ce 3+ , Pr 3+ , Nd 3+ , Pm 3+ , Sm 3+ , Eu 3+ , Gd 3+ , Tb 3+ , Dy 3+ , Ho 3+ , Er 3+ , Tm 3+ , Yb 3+ , Lu 3+ or a substrate comprising reactive light-emitting nano or microparticles comprising a core of a rare earth ceramic material selected from the group of combinations thereof.

[0040] A non-transitory storage medium containing program instructions for implementing a computer-based method for detecting reactive light-emitting nanoparticles on a substrate or surface, the program instructions including instructions executable by a data processor to perform any of the methods described above.

Brief Description of the Drawings

[0041] The following drawings present preferred embodiments for explaining the present disclosure and should not be regarded as limiting the scope of the invention.

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Embodiments for Carrying Out the Invention

[0042] Figure 1 shows a schematic view seen from the bottom side of an embodiment of the enclosure, where the slit portion 100 is used to allow light to pass from the light emitter 101 to the substrate, and the light is reflected by the substrate and returned to the photodiode sensor 102. The side opening is used for cable connection to the power supply device by USB 103 and for communication purposes.

[0043] Figure 2 shows a detailed cross-sectional view of the enclosure, where a PCB 200 having upside-down SMT (Surface Mount Technology) components 201, a central photodiode sensor 202, and two juxtaposed light emitters 203 horizontally can be seen. At the bottom, there is an acrylic glass 204 used for protection from dust and as a visible light cut filter in this embodiment.

[0044] Figure 3 shows a detailed cross-section of the enclosure 300, where upside-down SMT light emitters 301 and photodiode sensors 302 can be seen along with an illustration of the angles of the incident light 303 and the reflected light 304 respectively to and from the substrate 305.

[0045] Figure 4 shows a schematic representation of an embodiment of the PCB layout of two LEDs 400 juxtaposed horizontally to the photodiode sensor 401, and the gray squares are SMT solder pads 402.

[0046] Figure 5 shows a schematic representation of a preferred embodiment of the PCB layout of two SMT LEDs 500 and two SMT photodiode sensors 501, and the gray shapes form SMT solder pads 502.

[0047] Figure 6 shows a block diagram of a microcontroller module (a processor having a DSP instruction 600, an ADC 601 with different input channels, a DAC 602, a RAM and a flash memory 603, a power supply 604 with a battery and a battery charging circuit, and several external communication means 605 such as, among others, USB, Bluetooth®, WiFi®).

[0048] Figure 7 shows a detailed circuit of photodiode 700 including a logarithmic OP-AMP 701 created with loop gain diode 702 and resistor 703.

[0049] Figure 8 shows a drive circuit 800 for an IR or UV LED controlled by a DAC signal using OP-AMP 801 and a constant current source 802.

[0050] Figure 9 shows results obtained by an embodiment having one photodiode sensor for a given substrate when LNP is present at concentrations of 400 ppm, 100 ppm, 10 ppm, when no LNP is present, and in the case of a black body (only reflection of the device).

[0051] Figure 10 shows results obtained from an embodiment having an OP-AMP logarithmic circuit and a second stage OP-AMP circuit for a given LNP at a concentration of 10 ppm.

[0052] Figure 11 shows results obtained by an embodiment with two different photodiode sensors for a set of substrates where LNP07 and LNP08 are present in different concentration sets. The graph shows the root mean square deviation (standard deviation) of the difference between the signals of the photodiodes as a function of time.

[0053] Figure 12 shows an explanatory diagram of the wavelength spectrum responses of two different photodiodes from different suppliers.

[0054] Due to the minute amount of energy received from the LNP, the enclosure's crack and cavity function as a dark room with acrylic glass installed on the front. This acrylic glass has the function of protecting the emitter and sensor from dust and dirt and is also used as a visible light cut filter. The dimensions affect the direction and angle of the incident light beam on the substrate and each reflected energy returning to the photodiode sensor. The sensor also has an optimal angle and an optimal angle that maximize the conversion of the received energy into an electrical signal.

[0055] The electrical signal of the sensor needs to be amplified and adapted to an analyzable ADC level. The use of a circuit based on a logarithmic OP-AMP for substantial amplification of minute signals is disclosed. Further, a second-stage linear amplification at the output of the circuit based on the logarithmic OP-AMP is used to enhance sensitivity further.

[0056] For high-level sensitivity, it is extremely important to avoid environmental light from reaching the photodiode. A true darkroom is essential but not sufficient on its own, and light is made to pass only through the crack openings of the device enclosure and be IR or UV light belonging to the emissions of the LEDs and LNPs. The enclosure has a flat surface, and the acrylic filter is perfectly aligned without gaps to enable complete contact with the substrate. The device is placed on a given substrate, and the darkness level is measured before irradiation of the substrate by IR or UV light. Under such conditions, if the photodiode receives a signal level exceeding a determined limit, the user is given information on the actual situation that gives an opportunity to move the device to a better position. The process of data acquisition will start with the ADC, in which case the DAC level progresses to the maximum level of IR or UV light and results in a loop where the intensity decreases step by step. The acquired signal needs to have a form as shown in FIG. 9 so that the device can be used for identification and quantification. The term identification is to be understood as the recognition of a given LNP present in the substrate, and the term quantification is the recognition of the concentration of the LNP in the substrate.

[0057] The purposeful software algorithm is executed by the DSP, and the results are transmitted through external communication channels such as USB, Bluetooth, WiFi, etc.

[0058] In one possible implementation scenario, the identification and quantification values are stored in a database or a remote storage infrastructure of a blockchain. In a preferred embodiment, the device is connected, using a USB cable, to an external device, such as even a smartphone, a tablet, or a computer. This external unit starts transmitting acquisition information regarding the location, date, and time to the device upon the user's request. The device that receives these information from the external device then creates a package of information of the identification and quantification parameters in addition to the location, date, and time. Finally, the package of information is transmitted to the remote storage infrastructure.

[0059] On the electronic circuit, each photodiode is polarized in the reverse polarity and the signal is amplified by an independent OP-AMP logarithm-based circuit connected to different ADC channels. As one of the photodiodes, VBP104FAS manufactured by Vishay Semiconductors, which has good responsiveness to infrared light, is used. Similar devices with different spectral responses are used from other manufacturers such as, among others, OSRAM and ON Semiconductor.

[0060] The near-infrared or ultraviolet light emitter is driven by an ON-OFF circuit together with an OP-AMP connected to a DAC that can control a constant current circuit for changing the intensity of the light. The driving of the infrared LED is a power supply by a constant current circuit. The infrared light emitter is a component (reference code SFH4640) based on an LED with high intensity and a narrow beam manufactured by OSRAM Opto Semiconductors, and according to the manufacturer, the intensity of the light emission can reach 1050 mW / sr. The microcontroller is used to moderately adapt the infrared or ultraviolet light and to acquire data for post-processing.

[0061] In a preferred embodiment that utilizes the DAC output from the microcontroller, the intensity of the infrared light can be adjusted, and the signal format can also be controlled. Through these intensity and time controls, the device can adapt or adjust IR or UV - type LEDs to the observation substrate so as to take the maximum intensity of the reflected energy of the LNP and avoid saturation of the photodiode sensor. Through this light control and adjustment process, the device expands the detection range to specialize for high - concentration LNP.

[0062] After the interruption of IR or UV light, the reflected energy of the LNP decreases with a predetermined time constant and according to a natural negative exponential function. The photodiode sensor is amplified by a logarithmic OP - AMP circuit, and as a result, that is, the input signal to the ADC is a line that is a function of time with a slope directly proportional to the decay time of the LNP.

[0063] The quantification of a given substrate with LNP, that is, the number of particles per square centimeter detected by the sensor, is related to the time when the energy of the light reaches the dark level.

[0064] For a substrate with a small amount of LNP, for example, 10 ppm, the reflected signal becomes extremely weak. By adding a second - stage amplification, the signal can be observed and used for identification and quantification. However, this circuit saturates as the concentration increases. Therefore, input the signals from both the output of the logarithmic OP - AMP and the output of the second - stage amplification into different ADC channels, giving the possibility to process different levels of LNP concentration.

[0065] Identification is possible by utilizing the difference in signals from the sensor. Since the photodiode has different spectral responses at different wavelengths, different signals are obtained. By calculating the root mean square deviation (standard deviation) of the time signal at each point, it is possible to characterize and associate a given trace for each LNP.

[0066] Disclosed is an apparatus comprising a darkroom enclosure for recognizing infrared (IR) and ultraviolet (UV) responsive luminescent nanoparticles in a substrate using a set of sensors. The apparatus includes one or more IR irradiation devices or UV irradiation devices for illuminating the luminescent nanoparticles, a slit for passing light, a driving device based on a constant current power supply, a set of sensors based on photodiodes, and a microcontroller having several ADC input channels and DAC outputs. All the photodiodes are different in terms of spectral sensitivity response. All the photodiodes are provided with independent logarithmic amplifier circuits. The signals of the logarithmic amplifiers of all the independent photodiodes are connected to different ADC input channels of the microcontroller. The IR irradiation device or UV irradiation device is controlled by the signal of the DAC microcontroller.

[0067] The term "comprising", as used herein, is always intended to indicate the presence of the recited features, integers, steps, components, but is not intended to preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[0068] The present disclosure should not be regarded as limiting the described embodiments in any sense, and those skilled in the art will foresee many possibilities for changes thereto. The above-described embodiments are combinable.

[0069] The claims further define the specific embodiments of the present disclosure.

Claims

1. An apparatus for detecting reaction-emissive nano- or microparticles embedded in a substrate or on a surface, an infrared irradiation device or an ultraviolet irradiation device for illuminating the emissive particles; a near-infrared photodiode sensor for capturing the near-infrared response of the illuminated emissive particles; a darkroom disposed on the substrate or the surface, the irradiation device and the photodiode sensor being provided inside the darkroom; a logarithmic amplifier for amplifying and linearizing the response signal captured by the photodiode sensor; an electronic data processor configured to detect the reaction-emissive particles, the detection being performed by: illuminating the substrate or the surface with the irradiation device; acquiring the signal captured, amplified and linearized by the photodiode sensor; and detecting the presence of the emissive particles on the substrate or the surface from the linearized attenuation of the acquired signal, the apparatus comprising.

2. The apparatus according to claim 1, wherein the electronic data processor is further configured to control the intensity of the light of the IR irradiation device or the UV irradiation device such that the captured signal has the near-infrared response of the emissive particles in a state where there is no near-infrared response of the substrate or the surface.

3. The apparatus according to claim 1 or 2, wherein the apparatus comprises: another near-infrared photodiode sensor having a spectral sensitivity response different from that of the first photodiode sensor; another logarithmic amplifier for amplifying and linearizing the signal received by the other photodiode sensor; and a differentiator for obtaining the difference between the signals received and amplified by each photodiode sensor.

4. The apparatus according to claim 3, wherein the electronic data processor is configured to detect a peak exceeding a predetermined threshold in the time-domain signal of the difference.

5. The apparatus according to claim 4, wherein the electronic data processor is configured to distinguish between luminescent particles having a spectral response different from the detected peak.

6. The apparatus according to any one of claims 1 to 5, wherein the apparatus comprises another microcontroller having a plurality of analog-to-digital converters, i.e., ADC inputs, and digital-to-analog converters, i.e., DAC outputs, and the DAC output is configured to control the intensity of the light of the IR irradiation device or the UV irradiation device, and the ADC input is connected to the near-infrared photodiode sensor.

7. The apparatus according to any one of claims 1 to 6, wherein the apparatus comprises a linear amplifier for further amplifying the signal captured, amplified, and linearized by each photodiode sensor.

8. The apparatus according to any one of claims 1 to 7, wherein the luminescent particles are reactive to wavelengths in the range of 750 to 2500 nm.

9. The apparatus according to any one of claims 1 to 8, wherein the IR irradiation device is an LED type IR irradiation device or a laser type IR irradiation device.

10. The apparatus according to any one of claims 1 to 9, wherein the UV irradiation device is an LED type UV irradiation device or a laser type UV irradiation device.

11. The apparatus according to any one of claims 1 to 10, wherein the substrate is a fabric substrate, a paper substrate, a plastic substrate, a metal substrate, a cork substrate, a wood substrate, a leather substrate, a fur substrate, or a combination thereof.

12. The apparatus according to any one of claims 1 to 11, wherein the logarithmic amplifier is an OP-AMP logarithmic amplifier.

13. In the apparatus according to any one of claims 1 to 12, the reactive luminescent nano- or microparticles are La ３＋ , Ce ３＋ , Pr ３＋ , Nd ３＋ , Pm ３＋ , Sm ３＋ , Eu ３＋ , Gd ３＋ , Tb ３＋ , Dy ３＋ , Ho ３＋ , Er ３＋ , Tm ３＋ , Yb ３＋ , Lu ３＋ , or an apparatus having a core of a rare earth ceramic material selected from the group of these combinations.

14. In the apparatus according to any one of claims 1 to 13, the reactive luminescent nano- or microparticles have a particle size between 10 nm and 25 μm.

15. A computer-based method for detecting reactive luminescent nano- or microparticles embedded in a substrate or surface, the method comprising: by an electronic data processor, Illuminating the substrate or surface with an infrared irradiation device or an ultraviolet irradiation device to illuminate the luminescent particles; Capturing the near-infrared response of the illuminated luminescent nanoparticles with a near-infrared photodiode sensor, wherein the irradiation device and the photodiode sensor are provided inside a darkroom disposed on the substrate or surface; Amplifying and linearizing the response signal captured by the photodiode sensor with a logarithmic amplifier; Acquiring the signal captured, amplified, and linearized by the photodiode sensor; Detecting the presence of the luminescent particles on the substrate or surface from the linearized attenuation of the acquired signal; And performing the above steps.

16. In the method according to claim 15, amplifying and linearizing, by another logarithmic amplifier, a signal received by another near-infrared photodiode sensor having a spectral sensitivity response different from that of the first photodiode sensor; obtaining, by a differentiator, a difference between the signals received and amplified by each photodiode sensor. A method comprising the steps of **Claim 17** In the method according to claim 16, comprising the step of detecting a peak exceeding a predetermined threshold in the time-domain signal of the difference. A method **Claim 18** In the method according to claim 17, comprising the step of distinguishing between luminescent particles having a spectral response different from that of the detected peak. A method **Claim 19** In the method according to claim 18, controlling the intensity of the light of the IR irradiation device or the UV irradiation device so that the captured signal has the near-infrared response of the luminescent particles in a state where there is no near-infrared response of the substrate or the surface. A method **Claim 20** In the method according to any one of claims 15 to 19, the luminescent particles exhibit reactivity with respect to wavelengths of 750 to 2500 nm. A method **Claim 21** In the method according to any one of claims 15 to 20, the substrate is a textile substrate, a paper substrate, a plastic substrate, a metal substrate, a cork substrate, a wood substrate, a leather substrate, a fur substrate, or a combination thereof. A method **Claim 22** In the method according to any one of claims 15 to 21, the reactive luminescent nano- or microparticles are La ３＋ , Ce ３＋ , Pr ３＋ , Nd ３＋ , Pm ３＋ , Sm ３＋ , Eu ３＋ , Gd ３＋ , Tb ３＋ , Dy ３＋, Ho ３＋ , Er ３＋ , Tm ３＋ , Yb ３＋ , Lu ３＋ , or a method having a core of a rare earth ceramic material selected from the group of combinations thereof.

23. A non-transitory storage medium including program instructions for implementing a computer-based method for detecting reaction-emissive nanoparticles on a substrate or surface, the program instructions including instructions executable by a data processor to perform the method according to any one of claims 15 to 22.

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