Near-infrared light-emitting device and infrared light-emitting equipment using same

Abstract

The invention provides a near-infrared light-emitting device and infrared light-emitting equipment applying the near-infrared light-emitting device, the near-infrared light-emitting device comprises an excitation light source, a first light-transmitting element, a light conversion element and a light guide mechanism, and the light conversion element comprises near-infrared light quantum dots and polymer resin; the light conversion element is arranged on one side of the light emitting surface of the excitation light source, and the first light transmission element, the light conversion element and the light guide mechanism are sequentially arranged in the direction away from the excitation light source; in the thickness direction of the first light-transmitting element, one surface of the first light-transmitting element faces the excitation light source, and the other surface faces the light conversion element; the heat conductivity coefficient lambda of the first light-transmitting element is 0.12 W / m.K to 2 W / m.K. The first light-transmitting element in the near-infrared light-emitting device can timely dredge heat generated when the light conversion element absorbs the exciting light, the light attenuation problem caused by heat accumulation is avoided, and the near-infrared light-emitting device can achieve stable light output and high light power output.

Description

Technical Field

[0001] The present invention belongs to the field of optical technology, and in particular, relates to a near-infrared light-emitting device and an infrared light-emitting device using the near-infrared light-emitting device. Background Art

[0002] Near-infrared quantum dots are a type of semiconductor nanomaterial with unique optical properties. They have the advantages of controllable size and adjustable energy band gap, so they have broad application prospects in optoelectronic devices, display technology, biomarkers and other fields. However, the luminescence stability of near-infrared quantum dots is poor. Usually, the luminescence of near-infrared quantum dots will be significantly attenuated or even quenched in a short period of time. Based on this, near-infrared light-emitting devices using near-infrared quantum dots as light sources are difficult to maintain stable near-infrared light output, and the service life cycle is too short and has no application value. This seriously hinders the application and development of near-infrared quantum dots in near-infrared light-emitting devices. Therefore, there is little in-depth research based on near-infrared quantum dots as light sources in the prior art.

[0003] In order to improve the luminescence stability of near-infrared quantum dots, the existing solutions are mainly to improve their stability by improving the preparation process of near-infrared quantum dots, optimizing the surface modification of quantum dots, etc. For example, by introducing stabilizers on the surface of quantum dots, the interaction between quantum dots and the external environment can be reduced, thereby improving their light stability. In addition, some researchers can also improve the thermal stability of quantum dots by encapsulating them in a solid matrix.

[0004] Although existing solutions can improve the stability of near-infrared quantum dots to a certain extent, there are still some problems. These methods mainly focus on the preparation and modification of quantum dots. While improving the stability of quantum dots, they often reduce the luminous efficiency of quantum dots, which is not conducive to the application of near-infrared quantum dots in high-brightness light-emitting devices. Summary of the invention

[0005] For light sources using near-infrared quantum dots as the main luminescent body, in order to improve the infrared light emitting efficiency and infrared light emitting stability of such light sources, the present invention provides a near-infrared light emitting device and an infrared light emitting device using the same.

[0006] According to a first aspect of the present invention, a near-infrared light-emitting device is provided, which comprises an excitation light source, a first light-transmitting element, a light-converting element and a light-guiding mechanism, wherein the light-converting element comprises near-infrared light quantum dots and a polymer resin, and the polymer resin serves as a dispersion medium for the near-infrared light quantum dots; the light-converting element is arranged on one side of a light-emitting surface of the excitation light source, and the first light-transmitting element, the light-converting element and the light-guiding mechanism are arranged in sequence in a direction away from the excitation light source; in a thickness direction of the first light-transmitting element, one side of the first light-transmitting element faces the excitation light source, and the other side faces the light-converting element; the minimum distance between the excitation light source and the light-converting element is d1, and the thickness of the first light-transmitting element is d2, d2≤d1, d2≥0.1 mm; the thermal conductivity of the first light-transmitting element is λ=0.12 W / m·K~2 W / m·K. In the near-infrared light-emitting device provided by the present invention, the thermal conductivity of the first light-transmitting element is in the range of 0.2 W / m·K to 2 W / m·K, and has a good heat transfer effect. Therefore, the first light-transmitting element is used as the heat dissipation medium of the light-converting element, and the heat generated by the light-emitting near-infrared light quantum dots can be timely channeled through the polymer resin and the first light-transmitting element, thereby avoiding the light decay phenomenon of the near-infrared light quantum dots caused by the accumulation of heat in the polymer resin. In summary, based on the setting of the first light-transmitting element, it can effectively regulate the heat distribution inside the near-infrared light-emitting device, so that the light-converting element can maintain a stable working state and can maintain a good light conversion efficiency for a long time.

[0007] Preferably, d2 ≥ 0.5 mm.

[0008] Preferably, d2=0.5 mm~5 cm.

[0009] As the thickness d2 of the first light-transmitting element increases, the heat dissipation effect of the first light-transmitting element is enhanced, and the luminous stability of the light-converting element is improved accordingly. However, when d2 reaches 2 cm, the luminous stability of the light-converting element will not be significantly improved as d2 increases further, that is, the heat dissipation effect of the first light-transmitting element reaches a plateau in improving the luminous stability of the light-converting element.

[0010] Preferably, the thermal conductivity of the first light-transmitting element is λ=0.2 W / m·K to 1.2 W / m·K.

[0011] Preferably, the first light-transmitting element is glass.

[0012] Preferably, the arrangement of the first light-transmitting element satisfies the following a, b or c: a. The first light-transmitting element contacts the surface of the excitation light source and the surface of the light-converting element respectively; b. The first light-transmitting element and the excitation light source are fixedly installed, and the first light-transmitting element and the excitation light source are spaced apart; c. The first light-transmitting element and the light-converting element are movably installed, so that the first light-transmitting element and the light-converting element can move along the propagation direction of the light path of the excitation light source.

[0013] When the light power of the excitation light source is relatively small, the thermal effect generated by the excitation light source is relatively small. At this time, method a can be selected, and no spacing is set between the excitation light source, the first light-transmitting element, and the light-converting element, so that the excitation light source, the first light-transmitting element, and the light-converting element maintain a compact structure, which is also conducive to the excitation light emitted by the excitation light source being effectively absorbed by the light-converting element. For example, when the light power of the excitation light source does not exceed 1 W / cm 2 You can choose method a.

[0014] As the optical power of the excitation light source increases, the heat generated by the excitation light source becomes larger. At this time, method b can be selected to set a gap between the excitation light source and the first light-transmitting element. The gap is filled with air. The thermal conductivity of air is low, so the gap can act as a heat-insulating area, which can prevent the heat generated by the excitation light source from migrating to the first light-transmitting element and the light-converting element, and allow the heat from the excitation light source to be slowly transferred in the gap. The heat in the gap reaches the first light-transmitting element in batches and in small quantities, and can be promptly discharged under the heat dissipation effect of the first light-transmitting element, thereby effectively preventing the heat from the excitation light source from quickly reaching the area where the light-converting element is located through the first light-transmitting element, and effectively extending the service life of the light-converting element under high light power irradiation. For example: when the optical power of the excitation light source reaches 1 W / cm 2 ~ 5 W / cm 2 When 0cm<d1≤10cm; when the light power of the excitation light source is 5 W / cm 2 ~ 10 W / cm 2 When 5 cm<d1≤15 cm; when the light power of the excitation light source is 10 W / cm 2 ~ 500 W / cm 2 When 8 cm<d1≤15 cm; when the light power of the excitation light source exceeds 500 W / cm 2 , let 10 cm<d1<30 cm.

[0015] When method c is selected to flexibly install the first light-transmitting element and the light-converting element, the distance between the excitation light source and the first light-transmitting element and the light-converting element can be flexibly adjusted according to the actual light power of the excitation light source, thereby regulating the photothermal effect between the excitation light source and the light-converting element, thereby achieving the effect of improving both the luminous efficiency and the luminous stability of the light-converting element.

[0016] Preferably, the excitation light transmittance of the first light-transmitting element is greater than 80%, and the wavelength range of the excitation light is 250 nm to 980 nm. Thus, the excitation light that can effectively excite the near-infrared quantum dots to emit light can be fully utilized.

[0017] Preferably, the near-infrared light-emitting device further comprises a second light-transmitting element, which is arranged between the light-emitting side of the light-converting element and the light-guiding mechanism; the second light-transmitting element satisfies that the infrared light transmittance is ≥50% and the visible light transmittance is ≤80%. The second light-transmitting element is arranged on the light-emitting side of the light-converting element in order to regulate the light-emitting condition of the near-infrared light-emitting device. The visible light from the excitation light source cannot completely pass through the second light-transmitting element. Therefore, the visible light that is not absorbed by the near-infrared light quantum dots can be at least partially reflected under the action of the second light-transmitting element and will not be emitted along the light-guiding mechanism, thereby reducing the visible light emission intensity of the near-infrared light-emitting device, and avoiding the visible light that is not absorbed by the near-infrared light quantum dots during the operation of the near-infrared light-emitting device from directly irradiating the user and causing the user to feel photosensitivity discomfort, especially when the near-infrared light-emitting device is applied to some beauty instruments, facial or eye granular equipment, and the user needs to use the near-infrared light-emitting device to irradiate the face and eyes.

[0018] Preferably, the light guide mechanism includes a focusing lens and a light guide element, and the light guide element includes at least one of a light guide tube and an optical fiber. After the scattered infrared light emitted from the light conversion element enters the light guide mechanism, it is converged by the focusing lens, thereby obtaining focused infrared light, and then the focused infrared light is coupled into the light guide element, and the light is output to the outside through the light guide element, thereby providing infrared light irradiation with high radiation intensity and concentrated irradiation position to the irradiated object.

[0019] Preferably, the light guiding mechanism further comprises a beam expander, and the beam expander is connected to the light outlet of the light guiding element.

[0020] Preferably, the near-infrared light-emitting device further includes a refrigeration system, and the refrigeration system is arranged outside the first light-transmitting element and the light-converting element. Under the action of the refrigeration system, the heat generated during the operation of the near-infrared light-emitting device can be accelerated, and the working stability of the near-infrared light-emitting device can be further improved, and the service life of the near-infrared light-emitting device can be extended. In some specific embodiments, the refrigeration system is arranged outside the first light-transmitting element and the light-converting element, and the refrigeration system is directly in contact with the first light-transmitting element and the light-converting element or is arranged at intervals, which can effectively guide the working heat of the near-infrared light-emitting device through heat transfer.

[0021] Preferably, the light emission wavelength range of the light conversion element covers 900 nm to 1700 nm.

[0022] Preferably, the near-infrared light quantum dots include at least one of PbS quantum dots, PbSe quantum dots, PbTe quantum dots, Ag2S quantum dots, HgTe quantum dots, and InAs quantum dots.

[0023] Preferably, the near-infrared light quantum dots contained in the light conversion element include near-infrared light quantum dots I and near-infrared light quantum dots II; near-infrared light quantum dots I are PbS quantum dots, and the main peak of their emission spectrum is located in the range of 1200 nm to 1300 nm, and the half-peak width is 100 nm to 200 nm; near-infrared light quantum dots II are PbSe quantum dots, and the main peak of their emission spectrum is located in the range of 1350 nm to 1450 nm, and the half-peak width is 100 nm to 200 nm.

[0024] Preferably, the polymer resin includes at least one of epoxy resin, silicone resin, acrylic resin, olefin resin, polyester resin, polyether ketone resin, alkyd resin, amino resin, polyurethane, rubber resin, nitro resin, cellulose resin, perchlorethylene resin, phenolic resin and silicone rubber.

[0025] Preferably, the polymer resin includes at least one of epoxy resin, silicone resin, polyurethane and silicone rubber. Selecting the above materials as the dispersion medium of near-infrared light quantum dots is conducive to further improving the luminous stability of the light conversion element and extending the service life of the near-infrared light-emitting device.

[0026] Preferably, in the light conversion element, the mass ratio of the polymer resin to the near-infrared light quantum dots satisfies the mass of the near-infrared light quantum dots: the mass of the polymer resin = 0.5-10:100.

[0027] Preferably, the light conversion element is in the form of a film, and the near-infrared light quantum dot content in the light conversion element is 0.001 mg / cm 2 ~10mg / cm 2 .

[0028] Preferably, the light conversion element further includes a diffusant, and the diffusant and the near-infrared light quantum dots are dispersed together in the polymer resin, and the diffusant includes at least one of organic silicon microspheres, silicon dioxide microspheres, polystyrene microspheres, PMMA microspheres, titanium dioxide particles, zinc oxide particles, barium sulfate particles, glass microspheres, aluminum oxide particles, and zirconium oxide particles. The diffusant can improve the luminous efficiency of the infrared quantum dots.

[0029] Preferably, the light conversion element further comprises a diffusant, and the diffusant and the near-infrared light quantum dots are co-dispersed in the polymer resin, and the diffusant comprises at least one of organic silicon microspheres, glass microspheres, and barium sulfate particles.

[0030] Preferably, D of the organosilicon microspheres 50 The glass beads have a D 50 The D 50 It is 200 nm~700 nm.

[0031] Preferably, the amount of the diffusing agent used satisfies the following ratio: mass of the diffusing agent: mass of the polymer resin = 2-50:100.

[0032] Preferably, the amount of near-infrared light quantum dots used satisfies the following ratio: mass of near-infrared light quantum dots: mass of polymer resin = 0.5-10:100.

[0033] Preferably, in the light conversion element, near-infrared light quantum dots are doped in a polymer resin.

[0034] Preferably, the light conversion element comprises a light conversion layer composed of near-infrared light quantum dots and polymer resin, and the light conversion element further comprises a first film layer and a second film layer, and the first film layer, the light conversion layer and the second film layer are stacked in sequence.

[0035] Preferably, the polymers constituting the first film layer and the second film layer are independently selected from at least one of polyvinyl alcohol, polyurethane, polyethylene terephthalate, ethylene-vinyl acetate copolymer, polyethylene, polymethyl methacrylate, polyvinyl chloride, polycarbonate, polypropylene, and polyamide (nylon).

[0036] Preferably, the polymers constituting the first film layer and the second film layer are independently selected from at least one of polyethylene terephthalate, polymethyl methacrylate, polycarbonate and polypropylene.

[0037] According to a second aspect of the present invention, a near-infrared light-emitting device is provided. As an alternative to the sequential arrangement of the first light-transmitting element, the light-converting element, and the light-guiding mechanism involved in the above-mentioned near-infrared light-emitting device, the first light-transmitting element is provided with a housing portion, and the light-converting element is arranged in the housing portion. Along the direction away from the excitation light source, the assembly consisting of the first light-transmitting element and the light-converting element, and the light-guiding mechanism are arranged in sequence. The manner in which the first light-transmitting element is provided with a housing portion includes, but is not limited to, a manner in which an inner cavity is provided inside the first light-transmitting element and a manner in which a groove is provided on the surface of the first light-transmitting element. When the inner cavity provided inside the first light-transmitting element is used as the above-mentioned housing portion, the light-converting element is placed in the inner cavity, and the excitation light originating from the excitation light source is incident on the first light-transmitting element and reaches the light-converting element. The light-converting element absorbs the excitation light and converts it into near-infrared light. The near-infrared light is emitted through the light-emitting surface of the first light-transmitting element and reaches the light-guiding mechanism. When the groove provided on the surface of the first light-transmitting element is used as the above-mentioned accommodating portion, the groove should be provided on the light-emitting surface of the first light-transmitting element. The excitation light from the excitation light source first passes through the first light-transmitting element and then reaches the light-converting element. The light-converting element absorbs the excitation light and converts it into near-infrared light before emitting it. The near-infrared light reaches the light-guiding mechanism.

[0038] According to a third aspect of the present invention, a near-infrared light device is provided, which includes the near-infrared light-emitting device as described above, and the near-infrared light device is an imager, a diagnostic instrument, a physical therapy instrument, a beauty instrument, and a hair growth instrument. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only embodiments of a part of the present invention, rather than all embodiments.

[0040] Example 1 The present embodiment provides a near-infrared light-emitting device, which includes a housing, an excitation light source, a first light-transmitting element, a light-deflecting element, a focusing lens, and an infrared optical fiber. The excitation light source, the first light-transmitting element, the light-deflecting element, and the focusing lens are all arranged inside the housing. The housing includes a closed first end and a second end with an opening connected to the outside. The excitation light source is arranged close to the first end, and the light-emitting surface of the excitation light source faces the second end. The first light-transmitting element, the light-deflecting element, the focusing lens, and the infrared optical fiber are sequentially arranged on one side of the light-emitting surface of the excitation light source. One end of the infrared optical fiber extends into the interior of the housing, and the other end extends from the opening at the second end of the housing. The above-mentioned focusing lens included in the near-infrared light-emitting device of the present embodiment is a Fresnel lens, and the focusing lens and the infrared optical fiber together constitute the light-guiding mechanism of the near-infrared light-emitting device.

[0041] The excitation light source used in this embodiment is a laser chip that can emit 450 nm excitation light. The optical power of the laser chip under standard working conditions is 1 W / cm 2 .

[0042] The first light-transmitting element is a custom-made optical glass, and the first light-transmitting element satisfies the requirement that the light transmittance of the excitation light (250 nm to 980 nm) reaches more than 90%. Inside the housing of the near-infrared light-emitting device, in the thickness direction of the first light-transmitting element, one side of the first light-transmitting element faces the excitation light source and contacts it, and the other side faces the light-converting element and contacts it. Therefore, d1 represents the minimum distance between the excitation light source and the light-converting element, and d2 represents the thickness of the first light-transmitting element, and d1=d2.

[0043] In this embodiment, the light conversion element used is composed of a first film layer, a light conversion layer, and a second film layer stacked in sequence. The first film layer and the second film layer are both films formed by curing polyethylene terephthalate (PET) (manufacturer: DuPont, manufacturer product number: PT7086), and the thickness of the first film layer and the second film layer is 100 μm. The thickness of the light conversion layer is 30 μm. In the light conversion layer, a polymer resin is used as the dispersion medium of the near-infrared light quantum dots. In this embodiment, epoxy resin (manufacturer: Dow Corning, product manufacturer number: 0E6550AB) is used as the above-mentioned polymer resin, and PbS quantum dots are used as the above-mentioned near-infrared light quantum dots. The emission spectrum of the PbS quantum dots has a main peak wavelength of 1200 nm, a wavelength range of 1080 nm to 1390 nm, and a half-peak width of 148 nm. The preparation method and process of the light conversion layer are as follows: prepare a toluene solution containing the above-mentioned PbS quantum dots, then add epoxy resin and curing agent thereto, stir thoroughly, thereby obtaining a quantum dot coating liquid, wherein the mass ratio of each material is PbS quantum dots: epoxy resin = 0.5:50, apply the above-mentioned quantum dot coating liquid on the surface of the first film layer, control the coating thickness according to the preset thickness of the light conversion layer, and then dry and cure the coating formed by the above-mentioned quantum dot coating liquid at 110°C for about 10 minutes, thereby obtaining a light conversion layer, and then use glue to bond the second film on the surface of the light conversion layer, thereby obtaining the light conversion element used in this embodiment. In the light conversion element prepared in this embodiment, the content of the above-mentioned PbS quantum dots is 0.5 mg / cm 2 . In this embodiment, different near-infrared light-emitting devices are prepared using the first light-transmitting element included in the near-infrared light-emitting device as a variable, and the product numbers and the specific conditions of the corresponding first light-transmitting elements are shown in Table 1, wherein λ represents the thermal conductivity of the first light-transmitting element. Among the near-infrared light-emitting devices prepared in this embodiment, except for the variables shown in Table 1, the materials, structures, and connection and installation relationships of other components are strictly kept consistent.

[0044] Table 1. Product numbers of Example 1 and details of the first light-transmitting elements used

[0045] Comparative Example 1 Taking the near-infrared light-emitting device of Example 1 as a reference, this comparative example uses the first light-transmitting element included in the near-infrared light-emitting device as a variable to prepare different near-infrared light-emitting devices. The product numbers and the specific conditions of the corresponding first light-transmitting elements are shown in Table 2, wherein the near-infrared light-emitting device D1-1 is not provided with a first light-transmitting element, so the items corresponding to the near-infrared light-emitting device D1-1 in Table 2 are all represented by " / ". In the near-infrared light-emitting device D1-1, the excitation light source and the light-converting element are separated by a hollow spacing area so that the minimum distance d1 between the two is equal to the minimum distance d1 between the excitation light source and the light-converting element in the near-infrared light-emitting device 1-1 of Example 1. Among the near-infrared light-emitting devices prepared in this comparative example, except for the variables shown in Table 2, the materials, structures, and connection and installation relationships of other components are strictly consistent with those of the near-infrared light-emitting device 1-1 of Example 1.

[0046] Table 2. Product numbers of comparative example 1 and details of the first light-transmitting element used

[0047] Example 2 The present embodiment provides a near-infrared light-emitting device, which includes a housing, an excitation light source, a first light-transmitting element, a light-deflecting element, a focusing lens, and an infrared optical fiber. The excitation light source, the first light-transmitting element, the light-deflecting element, and the focusing lens are all arranged inside the housing. The housing includes a closed first end and a second end with an opening connected to the outside. The excitation light source is arranged close to the first end, and the light-emitting surface of the excitation light source faces the second end. The first light-transmitting element, the light-deflecting element, the focusing lens, and the infrared optical fiber are sequentially arranged on one side of the light-emitting surface of the excitation light source. One end of the infrared optical fiber extends into the interior of the housing, and the other end extends from the opening at the second end of the housing. The above-mentioned focusing lens included in the near-infrared light-emitting device of the present embodiment is a Fresnel lens, and the focusing lens and the infrared optical fiber together constitute the light-guiding mechanism of the near-infrared light-emitting device.

[0048] The excitation light source used in this embodiment is a laser chip that can emit 450 nm excitation light. The optical power of the laser chip under standard working conditions is 3 W / cm 2 .

[0049] The first light-transmitting element is a custom-made optical glass, and the first light-transmitting element satisfies the light transmittance of the excitation light (250 nm to 980 nm) to be above 90%. Inside the housing of the near-infrared light-emitting device, in the thickness direction of the first light-transmitting element, one side of the first light-transmitting element faces the excitation light source, and the other side faces the light-converting element and contacts it. A hollow spacing space is provided between the first light-transmitting element and the excitation light source so that the first light-transmitting element and the excitation light source are 8 cm apart. Therefore, d1 represents the minimum distance between the excitation light source and the infrared light quantum dot light-converting element, and d2 represents the thickness of the first light-transmitting element, d1=d2+8cm.

[0050] In this embodiment, the infrared light quantum dot light conversion element used is a quantum dot light conversion film doped with near-infrared light quantum dots, with a thickness of 100 μm. In the above quantum dot light conversion film, a polymer resin is used as a dispersion medium for near-infrared light quantum dots. In this embodiment, polyurethane (manufacturer: Borodalifeng, product manufacturer number: SOI-3) is used as the above polymer resin, and PbSe quantum dots are used as the above near-infrared light quantum dots. The emission spectrum of the PbSe quantum dots has a main peak wavelength of 1400 nm, a wavelength range of 1240 nm to 1620 nm, and a half-peak width of 140 nm. The preparation method of the quantum dot light conversion film is as follows: weigh 1 mL of a PbSe quantum dot solution with a concentration of 30 mg / mL, add it to 5 g of polyurethane containing a curing agent and a dispersant, mix it thoroughly, and apply it to the surface of the first light-transmitting element to obtain a light conversion coating, and then cure the light conversion coating to obtain the above quantum dot light conversion film. In the quantum dot light conversion film prepared in this embodiment, the content of the above-mentioned PbSe quantum dots is 0.2 mg / cm 2 . In this embodiment, different near-infrared light-emitting devices are prepared using the first light-transmitting element included in the near-infrared light-emitting device as a variable, and the product numbers and the specific conditions of the corresponding first light-transmitting elements are shown in Table 3, wherein λ represents the thermal conductivity of the first light-transmitting element. Among the near-infrared light-emitting devices prepared in this embodiment, except for the variables shown in Table 3, the materials, structures, and connection and installation relationships of other components are strictly kept consistent.

[0051] Table 3. Product numbers of Example 2 and details of the first light-transmitting elements used

[0052] Comparative Example 2 Taking the near-infrared light-emitting device of Example 2 as a reference, this comparative example uses the first light-transmitting element included in the near-infrared light-emitting device as a variable to prepare different near-infrared light-emitting devices. The product numbers and the specific conditions of the corresponding first light-transmitting elements are shown in Table 4, wherein the near-infrared light-emitting device D2-1 is not provided with a first light-transmitting element, so the items corresponding to the near-infrared light-emitting device D2-1 in Table 4 are all represented by " / ". In the near-infrared light-emitting device D2-1, the excitation light source and the light-converting element are separated by a hollow spacing area so that the minimum distance d1 between the two is equal to the minimum distance d1 between the excitation light source and the light-converting element in the near-infrared light-emitting device 2-1 of Example 2. Among the near-infrared light-emitting devices prepared in this comparative example, except for the variables shown in Table 4, the materials, structures, and connection and installation relationships of other components are strictly consistent with those of the near-infrared light-emitting device 2-1 of Example 2.

[0053] Table 4. Product numbers of comparative example 2 and details of the first light-transmitting element used

[0054] Example 3 The present embodiment provides a near-infrared light-emitting device, which includes a housing, an excitation light source, a first light-transmitting element, a light-deflecting element, a focusing lens, and an infrared optical fiber. The excitation light source, the first light-transmitting element, the light-deflecting element, and the focusing lens are all arranged inside the housing. The housing includes a closed first end and a second end with an opening connected to the outside. The excitation light source is arranged close to the first end, and the light-emitting surface of the excitation light source faces the second end. The first light-transmitting element, the light-deflecting element, the focusing lens, and the infrared optical fiber are sequentially arranged on one side of the light-emitting surface of the excitation light source. One end of the infrared optical fiber extends into the interior of the housing, and the other end extends from the opening at the second end of the housing. The above-mentioned focusing lens included in the near-infrared light-emitting device of the present embodiment is a Fresnel lens, and the focusing lens and the infrared optical fiber together constitute the light-guiding mechanism of the near-infrared light-emitting device.

[0055] The excitation light source used in this embodiment is a laser chip that can emit 450 nm excitation light. The optical power of the laser chip under standard working conditions is 5 W / cm 2 .

[0056] The first light-transmitting element is a custom-made optical glass, and the first light-transmitting element satisfies the light transmittance of the excitation light (250 nm to 980 nm) to be above 90%. Inside the housing of the near-infrared light-emitting device, in the thickness direction of the first light-transmitting element, one side of the first light-transmitting element faces the excitation light source, and the other side faces the light-converting element and contacts it. A hollow spacing space is provided between the first light-transmitting element and the excitation light source so that the first light-transmitting element and the excitation light source are 12 cm apart. Therefore, d1 represents the minimum distance between the excitation light source and the infrared light quantum dot light-converting element, and d2 represents the thickness of the first light-transmitting element, d1=d2+12 cm.

[0057] In this embodiment, the light conversion element used is composed of a first film layer, a light conversion layer, and a second film layer stacked in sequence. The first film layer and the second film layer are both film materials formed by PET curing, and the thickness of the first film layer and the second film layer is 100 μm. The thickness of the light conversion layer is 30 μm. In the light conversion layer, a polymer resin is used as the dispersion medium of the near-infrared light quantum dots. This embodiment uses epoxy resin (manufacturer: Dow Corning, product manufacturer number: 0E6550AB) as the above-mentioned polymer resin, and Ag2S quantum dots are used as the above-mentioned near-infrared light quantum dots. The main peak wavelength of the emission spectrum of the Ag2S quantum dots is 1100 nm, the wavelength range is 950 nm to 1310 nm, and the half-peak width is 145 nm. The preparation method and process of the light conversion layer are as follows: 1) Prepare a toluene solution containing the above-mentioned Ag2S quantum dots, then add epoxy resin and curing agent thereto, stir thoroughly, thereby obtaining a quantum dot coating liquid, wherein the mass ratio of each material is Ag2S quantum dots: epoxy resin = 0.5:50, apply the above-mentioned quantum dot coating liquid on the surface of the first film layer, control the coating thickness according to the preset thickness of the light conversion layer, and then dry and cure the coating formed by the above-mentioned quantum dot coating liquid at 110°C for about 10 minutes to obtain a light conversion layer, and then use glue to bond the second film layer on the surface of the light conversion layer to obtain the light conversion element used in this embodiment. In the light conversion element prepared in this embodiment, the content of the above-mentioned Ag2S quantum dots is 1.2 mg / cm 2 . In this embodiment, different near-infrared light-emitting devices are prepared using the first light-transmitting element included in the near-infrared light-emitting device as a variable, and the product numbers and the specific conditions of the corresponding first light-transmitting elements are shown in Table 5, wherein λ represents the thermal conductivity of the first light-transmitting element. Among the near-infrared light-emitting devices prepared in this embodiment, except for the variables shown in Table 5, the materials, structures, and connection and installation relationships of other components are strictly kept consistent.

[0058] Table 5. Product numbers of Example 3 and details of the first light-transmitting elements used

[0059] Comparative Example 3 Taking the near-infrared light-emitting device of Example 3 as a reference, this comparative example uses the first light-transmitting element included in the near-infrared light-emitting device as a variable to prepare different near-infrared light-emitting devices. The product numbers and the specific conditions of the corresponding first light-transmitting elements are shown in Table 6, wherein the near-infrared light-emitting device D3-1 is not provided with a first light-transmitting element, so the items corresponding to the near-infrared light-emitting device D3-1 in Table 6 are all represented by " / ". In the near-infrared light-emitting device D3-1, the excitation light source and the light-converting element are separated by a hollow spacing area so that the minimum distance d1 between the two is equal to the minimum distance d1 between the excitation light source and the light-converting element in the near-infrared light-emitting device 3-1 of Example 3. Among the near-infrared light-emitting devices prepared in this comparative example, except for the variables shown in Table 6, the materials, structures, and connection and installation relationships of other components are strictly consistent with those of the near-infrared light-emitting device 3-1 of Example 3.

[0060] Table 6. Product numbers of comparative example 3 and details of the first light-transmitting element used

[0061] Test Example 1 1. Test subjects The near-infrared light-emitting devices prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were used as test objects.

[0062] 2. Light attenuation test The test duration of the short-term light decay test is 6 hours. During the test, the test object is placed in a standard working state. At the beginning and end of the test, the emission spectrum of the test object is tested respectively. The maximum luminous intensity of the main peak in the infrared light region of the emission spectrum is read and recorded as I1 (at the beginning of the test) and I2 (at the end of the test).

[0063] Test conditions: 1) Use an infrared spectrometer (brand: Ocean Optics, model: NIR1700) as the test equipment, an integrating sphere as the light collecting device, an integration time of 100 ms, and a test range of 900-1700 nm; 2) Place the test object vertically at the light port of the integrating sphere; 3) Collect data: At the beginning of the test, measure the emission spectrum of the test object, read the maximum intensity of the main luminescence peak as I1, and measure the emission spectrum of the test object again after 3 hours of the test, and read the maximum luminescence intensity of the main luminescence peak as I2.

[0064] Calculate the light decay rate of the short-term light decay test according to the following formula: Light decay rate = (I1-I2 / I1) × 100%.

[0065] 3. Test results The excitation light source used in the test objects provided in Example 1 and Comparative Example 1 is relatively small, so in the assembly of the near-infrared light-emitting device, the excitation light source, the first light-transmitting element, and the light-converting element are stacked in sequence, which is conducive to keeping the device compact. Table 7 shows the light decay rate data measured by the test objects provided in Example 1 and Comparative Example 1. From the test results, the light decay rate measured by the test objects provided in Example 1 is lower than the light decay rate measured by the test objects provided in Comparative Example 1. Specifically: (1) In the test objects provided in Example 1 and Comparative Example 1, the light decay rate of the near-infrared light-emitting device D1-1 is significantly higher. The near-infrared light-emitting device D1-1 does not have a first light-transmitting element between the excitation light source and the light-conversion element as used by other near-infrared light-emitting devices, so that the heat of the excitation light source is directly transferred to the light-conversion element, causing the near-infrared light-emitting device D1-1 to exhibit significant light decay after a short period of operation.

[0066] (2) The test objects are grouped according to the first light-transmitting element with the same thickness d2 used by the test objects. Based on this, the near-infrared light-emitting device 1-1, the near-infrared light-emitting device 1-5, and the near-infrared light-emitting device D1-4 are grouped together for comparison, the near-infrared light-emitting device 1-2, the near-infrared light-emitting device 1-3, the near-infrared light-emitting device 1-4, and the near-infrared light-emitting device D1-3 are grouped together for comparison, and the near-infrared light-emitting device 1-6, the near-infrared light-emitting device D1-2, and the near-infrared light-emitting device D1-5 are grouped together for comparison. The difference between the test objects included in the same group is that the λ value of the first light-transmitting element used by the near-infrared light-emitting device is different. In the same group, when the λ value of the first light-transmitting element used by the near-infrared light-emitting device does not exceed 2W / m·K, as the λ value of the first light-transmitting element used increases, the heat dissipation capacity of the first light-transmitting element is enhanced, and the heat generated by the light emission of the near-infrared light quanta can be timely channeled through the polymer resin and the first light-transmitting element, so that the light decay rate of the near-infrared light-emitting device is reduced and the working stability is improved. Among the test objects, the λ value of the first light-transmitting element used in the near-infrared light-emitting device D1-2 is too low, and the heat from the near-infrared light quantum dots cannot be promptly diverted, resulting in heat accumulation in the light-transmitting element, which is manifested as a high light decay rate and insufficient working stability of the near-infrared light-emitting device D1-2. However, in the same group, when the λ value of the first light-transmitting element used in the near-infrared light-emitting device is further increased to more than 2 W / m·K, the working stability of the near-infrared light-emitting device using the first light-transmitting element with a higher λ value becomes worse. For example, the light decay rates measured for the near-infrared light-emitting devices D1-3, D1-4, and D1-5 are higher than those of the near-infrared light-emitting devices in the same group that use the first light-transmitting element with a λ value of 0.2 W / m·K to 2 W / m·K. Although the first light-transmitting element used in the above three near-infrared light-emitting devices has a good heat dissipation effect, its thermal conductivity effect on the heat from the light source makes the heat reach the light conversion element faster, resulting in an enhanced thermal effect in the area near the near-infrared light quantum dots, which is manifested as poor working stability of the near-infrared light-emitting devices and an increase in the light decay rate.

[0067] (3) On the other hand, the test objects are grouped according to the first light-transmitting element with the λ value used by the test objects. Based on this, the near-infrared light-emitting devices 1-4, near-infrared light-emitting devices 1-5, near-infrared light-emitting devices 1-6, near-infrared light-emitting devices 1-7, and near-infrared light-emitting devices 1-8 are grouped into the same group for comparison, and the near-infrared light-emitting devices 1-1 and near-infrared light-emitting devices 1-3 are grouped into the same group for comparison. The difference between the test objects included in the same group is that the thickness d2 value of the first light-transmitting element used by the near-infrared light-emitting devices is different. As the thickness d2 of the first light-transmitting element used increases, the heat dissipation effect of the first light-transmitting element d2 is enhanced. On the other hand, it can also extend the distance that the heat released from the excitation light source is transmitted to the light-converting element, thereby better avoiding the heat accumulation of the light-converting element, thereby reducing the light decay rate of the near-infrared light-emitting device. However, when the thickness d2 of the first light-transmitting element reaches 2 cm or more, the effect of further increasing d2 on the light decay rate will not be significant.

[0068] In summary, compared with the near-infrared light-emitting devices prepared in Comparative Example 1, the near-infrared light-emitting devices provided in Example 1 have a thermal conductivity in the range of 0.2 W / m·K to 2 W / m·K based on the application of the first light-transmitting element, which makes these near-infrared light-emitting devices have a more stable working state.

[0069] Table 7. Test result statistics of test case 1 (I)

[0070] Compared with the test objects provided in Example 1 and Comparative Example 1, the excitation light source light power used in the test objects provided in Example 2 and Comparative Example 2 is larger. In the assembly of the near-infrared light-emitting devices in Example 2 and Comparative Example 2, a hollow spacing space is provided between the first light-transmitting element and the excitation light source so that the first light-transmitting element and the excitation light source are 8 cm apart. Table 8 shows the light decay rate data measured by the test objects provided in Example 2 and Comparative Example 2. From the test results, the light decay rate measured by the test objects provided in Example 2 is lower than the light decay rate measured by the test objects provided in Comparative Example 2. Specifically: (1) In the test objects provided in Example 2 and Comparative Example 2, the light decay rate of the near-infrared light-emitting device D2-1 is significantly higher. The near-infrared light-emitting device D2-1 does not have a first light-transmitting element between the excitation light source and the light-conversion element as used by other near-infrared light-emitting devices, so that the heat of the excitation light source is directly transferred to the light-conversion element, causing the near-infrared light-emitting device D2-1 to exhibit significant light decay after a short period of operation.

[0071] (2) The test objects are grouped according to the first light-transmitting element with the same thickness d2 used by the test objects. Based on this, the near-infrared light-emitting device 2-1 and the near-infrared light-emitting device 2-5 are divided into the same group for comparison, the near-infrared light-emitting device 2-2, the near-infrared light-emitting device 2-3, and the near-infrared light-emitting device 2-4 are divided into the same group for comparison, and the near-infrared light-emitting device 2-6, the near-infrared light-emitting device D2-2, and the near-infrared light-emitting device D2-3 are divided into the same group for comparison. The difference between the test objects included in the same group is that the λ value of the first light-transmitting element used by the near-infrared light-emitting device is different. In the same group, when the λ value of the first light-transmitting element used by the near-infrared light-emitting device does not exceed 2 W / m·K, as the λ value of the first light-transmitting element used increases, the light decay rate of the near-infrared light-emitting device decreases and the working stability is improved. However, in the same group, when the λ value of the first light-transmitting element used by the near-infrared light-emitting device further increases to more than 2 W / m·K, the working stability of the near-infrared light-emitting device using the first light-transmitting element with a higher λ value becomes worse.

[0072] (3) On the other hand, the test objects are grouped according to the first light-transmitting element with the λ value used by the test objects. Based on this, the near-infrared light-emitting device 2-1 and the near-infrared light-emitting device 2-3 are grouped into the same group for comparison, and the near-infrared light-emitting device 2-4, the near-infrared light-emitting device 2-5, and the near-infrared light-emitting device 2-6 are grouped into the same group for comparison. The difference between the test objects included in the same group is that the thickness d2 value of the first light-transmitting element used by the near-infrared light-emitting device is different. As the thickness d2 of the first light-transmitting element used increases, the light decay rate of the near-infrared light-emitting device decreases.

[0073] Table 8. Test result statistics of test case 1 (II)

[0074] Compared with the test objects provided in Example 1 and Comparative Example 1, the excitation light source light power used in the test objects provided in Example 3 and Comparative Example 3 is larger. In the assembly of the near-infrared light-emitting device of Example 3 and Comparative Example 3, a hollow spacing space is provided between the first light-transmitting element and the excitation light source so that the first light-transmitting element and the excitation light source are 12 cm apart. Table 9 shows the light decay rate data measured by the test objects provided in Example 3 and Comparative Example 3. From the test results, the light decay rate measured by the test objects provided in Example 3 is lower than the light decay rate measured by the test objects provided in Comparative Example 3. Specifically: (1) In the test objects provided in Example 3 and Comparative Example 3, the light decay rate of the near-infrared light-emitting device D3-1 is significantly higher. The near-infrared light-emitting device D3-1 does not have a first light-transmitting element between the excitation light source and the light-conversion element as used by other near-infrared light-emitting devices, so that the heat of the excitation light source is directly transferred to the light-conversion element, causing the near-infrared light-emitting device D3-1 to exhibit significant light decay after a short period of operation.

[0075] (2) The test objects are grouped according to the first light-transmitting element with the same thickness d2 used by the test objects. Based on this, the near-infrared light-emitting device 3-1 and the near-infrared light-emitting device 3-5 are divided into the same group for comparison, the near-infrared light-emitting device 3-2, the near-infrared light-emitting device 3-3, the near-infrared light-emitting device 3-4 are divided into the same group for comparison, and the near-infrared light-emitting device 3-6, the near-infrared light-emitting device D3-2, and the near-infrared light-emitting device D3-3 are divided into the same group for comparison. The difference between the test objects included in the same group is that the λ value of the first light-transmitting element used by the near-infrared light-emitting device is different. In the same group, when the λ value of the first light-transmitting element used by the near-infrared light-emitting device does not exceed 2 W / m·K, as the λ value of the first light-transmitting element used increases, the light decay rate of the near-infrared light-emitting device decreases and the working stability is improved. However, in the same group, when the λ value of the first light-transmitting element used by the near-infrared light-emitting device further increases to more than 2 W / m·K, the working stability of the near-infrared light-emitting device using the first light-transmitting element with a higher λ value becomes worse.

[0076] (3) On the other hand, the test objects are grouped according to the first light-transmitting element with the λ value used by the test objects. Based on this, the near-infrared light-emitting device 3-1 and the near-infrared light-emitting device 3-3 are grouped together for comparison, and the near-infrared light-emitting device 3-4, the near-infrared light-emitting device 3-5, and the near-infrared light-emitting device 3-6 are grouped together for comparison. The difference between the test objects included in the same group is that the thickness d2 value of the first light-transmitting element used by the near-infrared light-emitting device is different. As the thickness d2 of the first light-transmitting element used increases, the light decay rate of the near-infrared light-emitting device decreases.

[0077] Table 9. Test result statistics of test case 1 (III)

[0078] Example 4 This embodiment uses the near-infrared light-emitting device 1-1 of embodiment 1 as a reference, and uses the polymer resin included in the light-conversion layer of the light-conversion element in the near-infrared light-emitting device as a variable to prepare different near-infrared light-emitting devices. The product numbers of the near-infrared light-emitting devices prepared in this embodiment and the polymer resin included in the light-conversion layer of the light-conversion element are shown in Table 10, wherein the purchase information of the polymer resin shown in Table 10 is as follows: epoxy resin, manufacturer Dow Corning, manufacturer product number: 0E6550AB; silicone resin, manufacturer: Kain Chemical, manufacturer product number: HP2020; polyurethane, manufacturer: Boluo Dalifeng, manufacturer product number: SOI-3; phenolic resin, manufacturer: Fangyu Chemical, manufacturer product number: SP-560; silicone rubber, manufacturer: Silicon Harbor Chemical, manufacturer product number: 107; acrylic resin, manufacturer: Kain Chemical, manufacturer product number: BA410; alkyd resin, manufacturer: Juji Chemical, manufacturer product brand: SH-benzoic acid modified alkyd resin. Among the near-infrared light-emitting devices prepared in this embodiment, except for the variables shown in Table 10, the materials, structures, and connection and installation relationships of other components are strictly consistent with the near-infrared light-emitting device 1-1 of Example 1. For the convenience of comparison, the relevant information of the near-infrared light-emitting device 1-1 of Example 1 is also included in Table 10.

[0079] Table 10. Product numbers and polymers contained in the light conversion components of Example 4

[0080] Example 5 This embodiment uses the near-infrared light-emitting device 2-1 of Example 2 as a reference, and uses the light-conversion element in the near-infrared light-emitting device, that is, the quantum dot light-conversion film, and the polymer resin contained therein as a variable to prepare different near-infrared light-emitting devices. The product numbers of the near-infrared light-emitting devices prepared in this embodiment and the polymer resin contained in the light-conversion element are shown in Table 12, wherein the purchase information of the polymer resin shown in Table 12 is as follows: epoxy resin, manufacturer Dow Corning, manufacturer product number: 0E6550AB; silicone resin, manufacturer: Kain Chemical, manufacturer product number: HP2020; polyurethane, manufacturer: Boroda Lifeng, manufacturer product number: SOI-3; phenolic resin, manufacturer: Fangyu Chemical, manufacturer product number: SP-560; silicone rubber, manufacturer: Silicon Harbor Chemical, manufacturer product number: 107; polyester resin, manufacturer: Covestro, manufacturer product number: polyester resin 930; acrylic resin, manufacturer: Sanmu Group, manufacturer product number: SM-8001. Among the near-infrared light-emitting devices prepared in this embodiment, except for the variables shown in Table 12, the materials, structures, and connection and installation relationships of other components are strictly consistent with the near-infrared light-emitting device 2-1 of Example 2. For the convenience of comparison, the relevant information of the near-infrared light-emitting device 2-1 of Example 2 is also included in Table 12.

[0081] Table 12. Product numbers and polymers contained in the light conversion components of Example 5

[0082] Test Example 2 1. Test subjects The infrared light-emitting devices prepared in Example 4 and Example 5 were used as test objects.

[0083] 2. Light attenuation test The test equipment, test conditions, and test operations used in the optical attenuation test of this test example are consistent with those in the optical attenuation test of Test Example 1.

[0084] 3. Test results The test results of this test example are shown in Table 14 and Table 15. For the convenience of comparison, the test results of the infrared light-emitting device 1-1 of Example 1 in Test Example 1 are recorded in Table 14, and the test results of the infrared light-emitting device 2-1 of Example 2 in Test Example 1 are recorded in Table 15. Comparing the data shown in Table 14 with the data shown in Table 15, it can be seen that for near-infrared light-emitting devices with the same device structure, the type of polymer resin used to prepare the light-conversion element will also have a certain impact on the working stability of the infrared light-emitting device. Based on the test results of this test example, the use of polyurethane, epoxy resin, silicone resin, and silicone rubber in the preparation of the light-conversion element is conducive to further improving the working stability of the near-infrared light-emitting device.

[0085] Table 14. Test result statistics of test case 2 (I)

[0086] Table 15. Test result statistics of test case 2 (II)

[0087] Example 6 This embodiment uses the near-infrared light-emitting device 1-1 of Embodiment 1 as a reference, and prepares different near-infrared light-emitting devices by introducing different diffusing agents into the light conversion layer of the light conversion element in the near-infrared light-emitting device.

[0088] In this embodiment, the preparation method of the light-conversion element of each near-infrared light-emitting device is as follows: a diffusing agent is dispersed in a toluene solvent to obtain a base liquid, a toluene solution containing near-infrared light quantum dots is prepared, and then the toluene solution is added to the base liquid, and then a polymer resin and a curing agent are added to the mixed liquid thus formed, and the mixture is fully stirred to obtain a quantum dot coating liquid, wherein the mass ratio of each material is near-infrared light quantum dots: polymer resin: diffusing agent = 0.5:50:15, the above-mentioned quantum dot coating liquid is coated on the surface of the first film layer, the coating thickness is controlled according to the preset thickness of the light-conversion layer, and then the coating formed by the above-mentioned quantum dot coating liquid is dried and cured at 110°C for about 10 minutes to obtain a light-conversion layer, and then a second film layer is bonded to the surface of the light-conversion layer with glue to obtain the light-conversion element used in this embodiment.

[0089] In this embodiment, the diffusing agent used to prepare the light conversion element is used as a variable to prepare different near-infrared light-emitting devices. The product numbers and the specific conditions of the corresponding diffusing agents are shown in Table 16. Among the near-infrared light-emitting devices prepared in this embodiment, except for the variables shown in Table 16, the materials, structures, and connection and installation relationships of other components are strictly consistent. Among them, the purchase information of the diffusing agent shown in Table 16 is as follows: silicone microspheres, manufacturer: Dinghai Plastic Chemical; glass microspheres, manufacturer: Zhichuan Technology; barium sulfate particles, manufacturer: Hongzhi New Materials.

[0090] Table 16. Diffusing agents contained in the product numbers and light conversion components of Example 6

[0091] Test Example 3 1. Test subjects The near-infrared light-emitting device 1-1 of Example 1 and the near-infrared light-emitting device prepared in Example 6 were used as test objects.

[0092] 2. Light attenuation test The test equipment, test conditions, and test operations used in the optical attenuation test of this test example are consistent with those in the optical attenuation test of Test Example 1.

[0093] 3. Test results The test results of this test example are shown in Table 17, wherein the data processing method of the I2 value (the maximum luminous intensity value of the main peak of the emission spectrum of the test object collected at the end of the test) shown in Table 17 is as follows: the I2 measured by the near-infrared light-emitting device 1-1 of Example 1 in this test example is used as the control value, which is recorded as 100%, and the corresponding measured I2 values ​​of other test objects are recorded at a ratio equivalent to the control value.

[0094] In the test objects of this test example, the light conversion elements of the test objects provided by Example 6 all contain diffusants. The introduction of diffusants can reflect and refract light, thereby increasing the luminous intensity of the light conversion elements. At the same time, different diffusants have different thermal conductivities, which will have a certain regulatory effect on the thermal effect in the light conversion elements. The light conversion element of the near-infrared light-emitting device 1-1 provided in Example 1 does not contain a diffusant, which serves as a control for the test objects of this test example. The test results of this test example are shown in Table 17.

[0095] Taking the near-infrared light-emitting device 1-1 provided in Example 1 as a control, the application of different diffusants will have an impact on the light decay rate of the test object. This is mainly because the introduction of diffusants with different thermal conductivities into the light conversion element changes the heat dissipation capacity of the light conversion element, thereby affecting the heating condition of the near-infrared light quantum dots during operation. In addition to the material type of the diffusant, the particle size of the diffusant will also have a certain influence on the heat dissipation capacity of the light conversion element. The heating condition of the near-infrared light quantum dots changes during operation, which is reflected in the change of the light decay rate of the near-infrared light-emitting device. From the test results of this test example, it can be seen that the use of PS microspheres or barium sulfate particles as diffusants slightly increases the light decay rate of the near-infrared light-emitting device, while the use of silicone microspheres as diffusants may increase the light decay rate of the near-infrared light-emitting device or decrease the light decay rate of the near-infrared light-emitting device.

[0096] Furthermore, at the end of the light decay rate test, the luminous intensity of the near-infrared light-emitting device 1-1 provided in Example 1 is used as a reference for the luminous intensity of other test objects in this test example, and the luminous intensity of the near-infrared light-emitting device provided in Example 6 at the end of the light decay rate test is compared. Since the introduction of the diffusant can reflect and refract light, the luminous intensity of the light conversion element can be increased. However, during the light decay test, the luminescence of the near-infrared light quantum dots decays to a certain extent due to thermal effects. The above two aspects simultaneously affect the luminous intensity of the near-infrared light-emitting device at the end of the light decay test. Introducing a diffusant with good thermal conductivity and good reflection and refraction into the light conversion element can enable the near-infrared light-emitting device using the diffusant to achieve a significantly higher luminous intensity than the reference at the end of the light decay test. Based on a comprehensive consideration of the working stability and luminous intensity of the near-infrared light-emitting device, if a diffusant is used to participate in the preparation of the light conversion element of the near-infrared light-emitting device, when silicone spheres are used as diffusants, the D 50 The preferred size is 1 μm to 5 μm. When PS microspheres are used as diffusants, the D 50 Preferably, it is 1 μm to 5 μm. When barium sulfate particles are used as a diffusant, the D 50 It is preferably 200 nm to 700 nm.

[0097] Table 17. Test result statistics of test case 3

[0098] Example 7 In this embodiment, a near-infrared light-emitting device is prepared with reference to the near-infrared light-emitting device 1-1 in Embodiment 1, and the specific numbers are near-infrared light-emitting device 7-1 and near-infrared light-emitting device 7-2.

[0099] Compared with the near-infrared light-emitting device 1-1, the near-infrared light-emitting device 7-1 is different in that the near-infrared light quantum dots contained in the light conversion layer of the light conversion element used in the near-infrared light-emitting device 7-1 are near-infrared light quantum dots I and near-infrared light quantum dots II; near-infrared light quantum dots I are PbS quantum dots, and the main peak wavelength of their emission spectrum is 1250 nm, the wavelength range is 1000 nm to 1450 nm, and the half-peak width is 150 nm; near-infrared light quantum dots II are PbSe quantum dots, and the main peak wavelength of their emission spectrum is 1400 nm, the wavelength range is 1240 nm to 1620 nm, and the half-peak width is 140 nm; calculated by mass ratio, near-infrared light quantum dots I: near-infrared light quantum dots II=1:1.5.

[0100] Compared with the near-infrared light-emitting device 1-1, the near-infrared light-emitting device 7-2 has the following differences in structure: the near-infrared light quantum dots contained in the light conversion layer of the near-infrared light-emitting device 7-2 for preparing the light conversion element are near-infrared light quantum dots I and near-infrared light quantum dots II; near-infrared light quantum dots I are PbS quantum dots, and the main peak wavelength of their emission spectrum is 1250 nm, the wavelength range is 1000 nm to 1450 nm, and the half-peak width is 150 nm; near-infrared light quantum dots II are PbS quantum dots, and the main peak wavelength of their emission spectrum is 1405 nm, the wavelength range is 1220 nm to 1650 nm, and the half-peak width is 145 nm; calculated by mass ratio, near-infrared light quantum dots I: near-infrared light quantum dots II=1:1.5.

[0101] In addition to the above differences, the materials, structures, and connection and installation relationships of other components of the near-infrared light-emitting device 7-1 and the near-infrared light-emitting device 7-2 are strictly consistent with the near-infrared light-emitting device 1-1 of Example 1.

[0102] Test Example 4 1. Test subjects The near-infrared light-emitting device prepared in Example 7 was used as a test object.

[0103] 2. Light attenuation test The test equipment, test conditions, and test operations used in the light decay test of this test example are consistent with those in the light decay test of Test Example 1. In addition, in this test example, the wavelength of the highest luminous intensity in the main peak of the emission spectrum of the test object is recorded: at the beginning of the test, the wavelength of the highest luminous intensity in the main peak of the emission spectrum of the test object is recorded (recorded as X1); after the test is carried out for 3 hours, the wavelength of the highest luminous intensity in the main peak of the emission spectrum of the test object is recorded (recorded as X2).

[0104] 3. Test results The test results are shown in Table 18. From the test results, it can be seen that the wavelength corresponding to the main peak of the emission spectrum of the participating near-infrared light-emitting devices measured at the beginning and end of the test is different. This is due to the different degrees of light decay of different quantum dots during the test. Compared with PbS quantum dots, the light decay of PbSe quantum dots is greater, which makes the emission spectrum of near-infrared light-emitting device 7-1 blue shifted by a greater distance before and after the test.

[0105] Table 18. Test result statistics of test case 4

[0106] Example 8 In this embodiment, a near-infrared light-emitting device is prepared with reference to the near-infrared light-emitting device 2-1 of embodiment 2, and is specifically numbered as near-infrared light-emitting device 8. Compared with near-infrared light-emitting device 2-1, near-infrared light-emitting device 8 has the following differences in structure: the light-conversion element used in near-infrared light-emitting device 8 is composed of two layers of quantum dot light-conversion films (numbered as quantum dot light-conversion film 1 and quantum dot light-conversion film 2, respectively); the near-infrared light quantum dots contained in quantum dot light-conversion film 1 are PbS quantum dots (the content in quantum dot light-conversion film 1 is 0.2 mg / cm 2 ), the main peak wavelength of the emission spectrum of the PbS quantum dots is 1100 nm, the wavelength range is 950 nm to 1310 nm, and the half-peak width is 145 nm; the near-infrared light quantum dots contained in the quantum dot light conversion film 2 are PbS quantum dots (the content of which in the quantum dot light conversion film 2 is 0.5 mg / cm 2 ), the emission spectrum of the PbS quantum dot has a main peak wavelength of 1200 nm, a wavelength range of 1080 nm to 1390 nm, and a half-peak width of 148 nm; the thickness of the quantum dot light-conversion film 1 and the quantum dot light-conversion film 2 are both 50 μm. In addition to the above differences, the materials, structures, and connection and installation relationships of the other components of the near-infrared light-emitting device 8 are strictly consistent with the near-infrared light-emitting device 2-1 of Example 2.

[0107] Example 9 In this embodiment, a near-infrared light-emitting device is prepared with reference to the near-infrared light-emitting device 1-1 of embodiment 1, and the specific number is near-infrared light-emitting device 9. Compared with the near-infrared light-emitting device 1-1, the difference between the near-infrared light-emitting device 9 and the near-infrared light-emitting device 1-1 is that the near-infrared light-emitting device 9 also includes a second light-transmitting element, which is an infrared high-transmittance filter (manufacturer: Eurowind Optics, manufacturer's product brand: long-wave pass filter @ 840 nm), and the infrared light (wavelength range 900 nm to 1700 nm) transmittance of the second light-transmitting element is 80% to 98%, and the visible light transmittance is 0% to 10%; the second light-transmitting element is stacked on the light-emitting side of the light-converting element. In addition to the above differences, the materials, structures, and connection and installation relationships of other components of the near-infrared light-emitting device 9 are strictly consistent with those of the near-infrared light-emitting device 1-1 of embodiment 1.

[0108] In the process of preparing the near-infrared light-emitting device in this embodiment, a second light-transmitting element is arranged on the light-emitting side of the light-deflecting element in order to regulate the light-emitting condition of the near-infrared light-emitting device. In this scheme, the infrared light emitted by the light-deflecting element can pass through the second light-transmitting element and be emitted from the near-infrared light-emitting device via the light-guiding mechanism, thereby realizing infrared light irradiation of the near-infrared light-emitting device, and when the visible light from the excitation light source reaches the second light-transmitting element, it can be reflected by the second light-transmitting element and will not be emitted along the light-guiding mechanism. Based on this, when the near-infrared light-emitting device is applied to some beauty instruments, facial or eye granular equipment, the user will not receive strong visible light irradiation when using the near-infrared light-emitting device to irradiate the face and eyes, thereby eliminating the discomfort caused by the visible light irradiation during use, such as glare, and improving the comfort of use.

[0109] The technical means of arranging a second light-transmitting element on the light-emitting side of the light-deflecting element is also applicable to other specific embodiments included in the present invention.

[0110] Example 10 In this embodiment, a near-infrared light-emitting device is prepared with reference to the near-infrared light-emitting device 2-1 of Example 2, and is specifically numbered as near-infrared light-emitting device 10. Compared with the near-infrared light-emitting device 2-1, the difference between the near-infrared light-emitting device 10 is that a slider-slideway mechanism, a slider-guide rail mechanism and other transmission components are provided between the side wall of the shell of the near-infrared light-emitting device and the first light-transmitting element, and the two are slidably connected through the above-mentioned transmission components so that the first light-transmitting element can move along the light path direction of the excitation light source. During the movement of the first light-transmitting element, the light-deflecting element stacked with the first light-transmitting element can also move with the first light-transmitting element. In addition to the above differences, the materials, structures, and connection and installation relationships of other components of the near-infrared light-emitting device 10 are strictly consistent with the near-infrared light-emitting device 2-1 of Example 2.

[0111] In the process of preparing the near-infrared light-emitting device in this embodiment, the first light-transmitting element and the light-converting element are set to be movably installed. Based on the above installation method, the distance between the excitation light source and the first light-transmitting element and the light-converting element can be flexibly adjusted according to the actual light power of the excitation light source, thereby regulating the photothermal effect between the excitation light source and the light-converting element, thereby achieving the effect of improving both the luminous efficiency and the luminous stability of the light-converting element.

[0112] The technical means of arranging the first light-transmitting element and the light-deflecting element to be movably installed is also applicable to other specific embodiments included in the present invention.

[0113] The above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention is described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the technical solutions of the present invention can be modified or equivalently replaced, but these modifications or replacements are all within the protection scope of the present invention.

Claims

1. A near-infrared light-emitting device, characterized in that: The near-infrared light emitting device comprises an excitation light source, a first light-transmitting element, a light-converting element and a light-guiding mechanism, wherein the light-converting element comprises near-infrared light quantum dots and a polymer resin, and the polymer resin serves as a dispersion medium for the near-infrared light quantum dots; The light deflection element is arranged on one side of the light emitting surface of the excitation light source, and the first light-transmitting element, the light deflection element, and the light-guiding mechanism are arranged in sequence in the direction away from the excitation light source; in the thickness direction of the first light-transmitting element, one side of the first light-transmitting element faces the excitation light source, and the other side faces the light deflection element; The minimum distance between the excitation light source and the light conversion element is d1, the thickness of the first light-transmitting element is d2, d2≤d1, d2≥0.1 mm; The thermal conductivity of the first light-transmitting element is λ=0.12 W / m·K to 2 W / m·K.

2. The near-infrared light-emitting device according to claim 1, characterized in that: d2≥0.5mm.

3. The near-infrared light emitting device according to claim 1, characterized in that: The thermal conductivity of the first light-transmitting element is λ=0.2 W / m·K to 1.2 W / m·K.

4. The near-infrared light-emitting device according to claim 1, characterized in that: The first light-transmitting element is arranged to satisfy the following a, b or c: a. The first light-transmitting element is in contact with the surface of the excitation light source and the surface of the light-converting element respectively; b. the first light-transmitting element is fixedly mounted to the excitation light source, and the first light-transmitting element is spaced apart from the excitation light source; c. The first light-transmitting element and the light-deflecting element are movably installed so that the first light-transmitting element and the light-deflecting element can move along the propagation direction of the light path of the excitation light source.

5. The near-infrared light-emitting device according to claim 1, characterized in that: The near-infrared light-emitting device also includes a second light-transmitting element, which is arranged between the light-emitting side of the light-converting element and the light-guiding mechanism; the second light-transmitting element satisfies that the infrared light transmittance is ≥50% and the visible light transmittance is ≤80%.

6. The near-infrared light emitting device according to claim 1, characterized in that: The light guiding mechanism comprises a focusing lens and a light guiding element, and the light guiding element comprises at least one of a light guiding tube and an optical fiber.

7. The near-infrared light emitting device according to claim 1, characterized in that: The near-infrared light-emitting device further includes a cooling system, which is arranged outside the first light-transmitting element and the light-converting element.

8. The near-infrared light-emitting device according to claim 1, characterized in that: The light-emitting wavelength range of the light-conversion element covers 900 nm to 1700 nm.

9. The near-infrared light emitting device according to claim 1, characterized in that: The polymer resin includes at least one of epoxy resin, silicone resin, acrylic resin, olefin resin, polyester resin, polyetherketone resin, alkyd resin, amino resin, polyurethane, rubber resin, nitro resin, cellulose resin, perchlorethylene resin, phenolic resin and silicone rubber.

10. The near-infrared light emitting device according to claim 9, characterized in that: In the light conversion element, the mass ratio of the polymer resin to the near-infrared light quantum dots satisfies the mass of the near-infrared light quantum dots: the mass of the polymer resin = 0.5-10:

100.

11. The near-infrared light emitting device according to claim 1, characterized in that: The light conversion element also includes a diffusant, and the diffusant and the near-infrared light quantum dots are co-dispersed in a polymer resin, and the diffusant includes at least one of silicone microspheres, silica microspheres, polystyrene microspheres, PMMA microspheres, titanium dioxide particles, zinc oxide particles, barium sulfate particles, glass microspheres, aluminum oxide particles, and zirconium oxide particles.

12. The near-infrared light-emitting device according to any one of claims 1 to 11, characterized in that: As an alternative to arranging the first light-transmitting element, the light-deflecting element, and the light-guiding mechanism in sequence, the first light-transmitting element is provided with a receiving portion, the light-deflecting element is arranged in the receiving portion, and along the direction away from the excitation light source, an assembly consisting of the first light-transmitting element and the light-deflecting element, and the light-guiding mechanism are arranged in sequence.

13. A near infrared light device, characterized in that: It comprises the near-infrared light emitting device as claimed in any one of claims 1 to 11, wherein the near-infrared light equipment is an imager, a diagnostic instrument, a physical therapy instrument, a beauty instrument, or a hair growth instrument.

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