Flexible rare earth composite packaging film for high-spectral purity yellow light illumination and preparation method thereof

Abstract

The application belongs to the technical field of optical materials, and particularly relates to a flexible rare earth composite packaging film for high-spectral-purity yellow light illumination and a preparation method thereof. The packaging film comprises, from the light-in side to the light-out side, a rare earth fluorescent layer, a rare earth functional layer and a resistance matching layer in sequence. The rare earth fluorescent layer is formed by compounding rare earth fluorescent powder and a high-molecular film-forming material, and is used for converting near-ultraviolet light into yellow light in the 500-700 nm band. The rare earth functional layer is composed of rare earth oxide nanoparticles and a high-molecular material, and is used for inhibiting ultraviolet residues and improving excitation light utilization rate through Mie scattering and intrinsic absorption. The resistance matching layer is composed of inorganic nanoparticles with different refractive indexes and a high-molecular material, and is used for reducing interface reflection and enhancing light transmission. The packaging film is applied to an LED excitation light source, and can realize high-spectral-purity yellow light illumination without ultraviolet and blue light components, and is suitable for the fields of semiconductor lithography, precise optical detection, cultural relic protection illumination and biological safety illumination.

Description

Technical Field

[0001] This invention belongs to the field of optical materials technology, specifically relating to a flexible rare earth composite encapsulation film for high-spectral purity yellow light illumination and its preparation method. Background Technology

[0002] As semiconductor manufacturing processes advance to sub-7 nanometer and below, lithography precision has entered the single-nanometer scale. The spectral purity of the light source in the lithography process has become a key factor affecting linewidth control. In mask inspection and optical alignment before extreme ultraviolet lithography (EUV), the ultraviolet or blue light components (<400 nm) in the auxiliary illumination source can trigger the pre-exposure reaction of the photoresist, leading to linewidth deviations or random defects in the developed image.

[0003] Currently, there are three main types of lighting that eliminates ultraviolet and blue light components: The first type involves modifying traditional light sources. This is done by coating the inner wall of mercury or sodium lamps with yellow phosphors and adding a yellow filter to absorb short-wavelength radiation below 500 nm, transmitting only the 570 nm-620 nm yellow light band. This type of solution typically uses absorption-type blocking methods (such as dyed films or TiO2 absorption layers) to directly absorb unconverted short-wavelength light and convert it into heat. While this effectively removes ultraviolet and blue light, it causes significant energy loss, reduces the overall luminous efficiency of the system, and generates waste heat. The second type is blue light chip excitation, such as that disclosed in patent CN107180907A. This method uses a blue LED chip with a wavelength of 415-500 nm as the excitation source, coated with yellow and orange phosphors. The high concentration of phosphors absorbs blue light and converts it into long-wavelength output. However, the phosphors cannot completely eliminate residual blue light. The third type is multi-chip mixed-light LED, as disclosed in patent CN214672603U, which directly combines red (610-650 nm) and yellow (560 nm-580 nm) LED chips and synthesizes pure yellow light through light power matching. Although the spectral purity is high, the yellow light chip has low efficiency, is difficult to manufacture and has a high cost. Summary of the Invention

[0004] To address the shortcomings of existing technologies in the field of high-spectral-purity lighting, such as insufficient spectral purification, low energy utilization, and poor flexibility, this invention proposes a flexible rare-earth composite encapsulation film for high-spectral-purity yellow light lighting and its preparation method. This encapsulation film achieves efficient spectral conversion and deep purification of near-ultraviolet light through the synergistic effect of multiple rare-earth functional structures, while also possessing high luminous efficiency, excellent thermal stability, and flexible adaptability.

[0005] To achieve the above-mentioned objectives, the present invention provides the following specific technical solutions: The first aspect of the present invention provides a flexible rare earth composite encapsulation film for high-spectral purity yellow light illumination, wherein the encapsulation film comprises, from the light incident side to the light emitting side, a rare earth fluorescent layer, a rare earth functional layer and an impedance matching layer. The rare earth fluorescent layer comprises rare earth phosphor and a polymer film-forming material, wherein the rare earth phosphor contains rare earth ions and a matrix, and the rare earth ions are selected from yttrium (Y). 3+ lanthanum (La) 3+ ), Praseodymium (Pr 3+ ), samarium (Sm 3+ Europium (Eu) 3+ ), gadolinium (Gd 3+ ) or terbium (Tb 3+ At least one of the following: the matrix is ​​selected from at least one of aluminates, silicates, titanates, vanadates, tungstates, phosphates, nitrides, or fluorides; The rare earth phosphor has an excitation peak in the near-ultraviolet band that matches the wavelength of the LED light source, and emits light with a wavelength of 500nm-700nm. The rare earth functional layer comprises rare earth oxide nanoparticles and polymer film-forming materials, which are used to generate Mie scattering in the 395 nm band, scattering the unabsorbed excitation light to the fluorescent layer for re-excitation, while using the intrinsic absorption of rare earth oxides to suppress ultraviolet components. The rare earth oxide nanoparticles are selected from at least one of cerium oxide, yttrium oxide, samarium oxide, gadolinium oxide, or europium oxide, and the particle size of the nanoparticles is 80-120 nm. The impedance matching layer is formed by combining inorganic nanoparticles with different refractive indices and polymer film-forming materials. The Fresnel reflection at the interface is reduced by the refractive index gradient structure, thereby achieving enhanced light transmission. The inorganic nanoparticles are selected from at least one of TiO2, SiO2 or ZrO2.

[0006] Furthermore, the rare earth phosphor has a mass fraction of 0.1%-10% and an emission wavelength range of 500-700 nm.

[0007] Furthermore, the inorganic nanoparticles in the impedance matching layer have a mass fraction of 0.01%-0.5%; the impedance matching layer forms a stepped refractive index gradient distribution along the light emission direction, with a refractive index range of 1.65-1.20.

[0008] Furthermore, the polymeric film-forming material is selected from at least one of polyimide, polymethyl methacrylate, polyethylene terephthalate, polycarbonate, polyvinyl naphthalate, or fluorinated ethylene propylene copolymer.

[0009] Preferably, the total thickness of the encapsulation film is 0.1-1.0 mm, the minimum bending radius is less than 10 mm, and it can be adapted to planar, curved and rollable optical systems.

[0010] A second aspect of the present invention provides a method for preparing the above-mentioned high-spectral-purity yellow light illumination flexible rare-earth composite encapsulation film, comprising the following steps: S1 Preparation of rare earth fluorescent layer: Rare earth fluorescent powder and polymer film-forming material are mixed at a predetermined mass ratio, dispersant and solvent are added, and dispersion treatment is performed to obtain rare earth fluorescent paste; the rare earth fluorescent paste is coated on the surface of the substrate and thermosetting to obtain rare earth fluorescent layer; S2 Preparation of rare earth functional layer: Rare earth oxide nanoparticles and polymer film-forming materials are mixed at a predetermined mass ratio, and dispersant and solvent are added. The mixture is then dispersed to obtain rare earth functional slurry. The rare earth functional slurry is coated onto the surface of the rare earth fluorescent layer and then thermosetting to obtain the rare earth functional layer. S3 Preparation of impedance matching layer: Inorganic nanoparticles with different refractive indices are mixed with polymer film-forming materials to form multiple films with refractive index gradients. Layered coating is used to gradually reduce the refractive index along the film thickness direction. The layers are coated and thermally cured in sequence to obtain the impedance matching layer. Finally, the layers are composited to obtain the overall multilayer flexible rare earth composite encapsulation film.

[0011] Furthermore, the dispersant is selected from at least one of ammonium polycarboxylate, polyvinylpyrrolidone, polyacrylate, sodium dodecyl sulfate, or nonionic surfactant, and is used to improve the wettability and dispersion stability of rare earth particles in a polymer matrix.

[0012] Furthermore, the solvent is selected from at least one of ethanol, isopropanol, propylene glycol methyl ether, cyclohexanone, butyl acetate, N,N-dimethylformamide, or N-methylpyrrolidone, and is used to adjust the viscosity of the slurry and the film-forming fluidity.

[0013] Furthermore, the dispersion treatment specifically involves first performing high-speed stirring at a speed of 500-1000 rpm for 10-20 minutes; then performing ultrasonic dispersion at a power of 200-400 W and a frequency of 20-40 kHz for 10-30 minutes.

[0014] Furthermore, the thermosetting includes hot pressing curing or hot air curing; the temperature is 80-100℃ and the time is 10-40 minutes, so that the film-forming material completes the cross-linking reaction and fixes the particle distribution.

[0015] A third aspect of the present invention provides the application of the composite encapsulation film or the preparation method described above in a high-spectral-purity yellow light illumination device.

[0016] In some embodiments, the flexible rare-earth composite encapsulation film is used for encapsulating LED excitation light sources.

[0017] The beneficial technical effects of this invention are as follows: With excellent UV and blue light suppression performance, the rare earth fluorescent layer efficiently converts 395 nm near-UV light into 500-700 nm yellow-red light, reduces reabsorption loss by utilizing a large Stokes shift, and achieves secondary utilization of excitation light under the Mie backscattering effect of the rare earth functional layer, thereby improving photon utilization and eliminating UV and blue light leakage.

[0018] Significantly improves the output intensity and luminous efficiency of the lighting source. The gradient refractive index design of the impedance matching layer reduces interface reflection, maintains high transmittance of the useful spectrum in the visible band, and avoids glare through scattering effect.

[0019] (3) It adopts an all-inorganic rare earth luminescence and absorption system, which has better thermal stability than quantum dot or organic luminescence materials, and has better resistance to decay and color stability under long-term working conditions.

[0020] (4) The preparation method is simple. The total thickness, mechanical flexibility and bending adaptability of the encapsulation film can be engineered by material formulation and interlayer stacking to meet the assembly requirements of planar, curved and rollable optical systems.

[0021] (5) It has extremely high application value and can be adapted to various scenarios with strict requirements for spectral purity. It is widely used in professional fields such as semiconductor lithography, precision optical inspection, cultural relic lighting, and biosafety lighting. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a high-spectral-purity yellow light illumination structure based on a flexible rare-earth composite encapsulation film in Example 1; Figure 2 This is a spectral diagram of a flexible rare-earth composite encapsulation film in Example 1; Figure 3 This is a spectral efficiency diagram of a flexible rare earth composite encapsulation film in Example 1. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0024] The encapsulation film of this invention comprises, from the light-incident side to the light-exit side, a rare-earth fluorescent layer, a rare-earth functional layer, and an impedance matching layer. The rare-earth fluorescent layer is used to down-convert near-ultraviolet (e.g., 395 nm) excitation light to 500-700 nm visible yellow-red light; the rare-earth functional layer improves the excitation light reuse rate and suppresses ultraviolet residue through intrinsic absorption and Mie backscattering; the impedance matching layer adopts a refractive index stepped or approximately continuous gradient structure to reduce Fresnel reflection at each interface, improve the useful light emission efficiency, and maintain the flexibility and rollable assembly adaptability of the film.

[0025] Example 1:

[0026] like Figure 1 As shown, this embodiment provides a high-spectral-purity yellow light illumination structure based on a flexible rare-earth composite encapsulation film. The high-spectral-purity yellow light illumination structure includes, from the light-incident side to the light-exit side, an LED excitation layer 1, a rare-earth fluorescent layer 2, a rare-earth functional layer 3, and an impedance matching layer 4.

[0027] The preparation method of a flexible rare-earth composite encapsulation film for high-spectral-purity yellow light illumination is as follows: Step 1: Take Ce 3+ :YAG and Eu 3+ A CaAlSiN3 mixed phosphor was prepared, with the mass ratio of phosphor to polyimide matrix controlled at 5:95. 1% (w / w) of polyvinylpyrrolidone dispersant was added. The mixture was first stirred at 800 rpm for 20 min, followed by ultrasonic treatment (300 W, 30 kHz, 30 min) to obtain a homogeneous slurry. The slurry was then coated onto the surface of the LED excitation layer using a blade coating method, with a thickness controlled at 400 μm. After thermosetting at 80 ℃ for 30 min, a rare-earth phosphor layer was obtained.

[0028] Step 2: Cerium oxide nanoparticles (average particle size approximately 100 nm) were mixed with polyethylene terephthalate at a mass ratio of 3:97. 2% (w / w) of N-methylpyrrolidone solvent was added, and the mixture was stirred at 500 rpm for 20 min, followed by ultrasonic dispersion (300 W, 30 kHz for 15 min) to form a uniformly dispersed slurry. The slurry was coated onto the surface of the rare-earth fluorescent layer, with a film thickness controlled at 100 μm, and then cured by hot air at 100 ℃ for 40 min to form the rare-earth functional layer.

[0029] Step 3: Inorganic nanoparticles are mixed with a polymethyl methacrylate (PMMA) matrix, with the mass fraction of inorganic nanoparticles controlled at 0.1%-0.5%. Multiple coating slurries with different refractive indices are prepared: a high refractive index slurry (TiO2 / PMMA), a medium refractive index slurry (ZrO2 / PMMA), and a low refractive index slurry (SiO2 / PMMA). 1% polyvinylpyrrolidone is added to each slurry, followed by dispersion treatment to form a uniformly dispersed slurry. Subsequently, the slurries with different refractive indices are sequentially coated onto the surface of the rare earth functional layer from high to low refractive index. The preferred film thickness for each coating is 0.5-5 μm, and the coating is cured at 80 ℃ for 10-15 min.

[0030] The final result is a high-spectral-purity yellow light illumination device based on a flexible rare-earth composite encapsulation film.

[0031] like Figure 2 As shown, under 395 nm near-ultraviolet light excitation, the emission spectrum of the flexible rare earth composite encapsulation film prepared in this embodiment is mainly distributed in the 500-700 nm band, and no ultraviolet and blue light residual components were detected in the spectrum, indicating that the encapsulation film can achieve high spectral purity yellow light output and maintain high luminescence intensity.

[0032] like Figure 3 As shown, relying on the spectral modulation and efficient energy conversion of the rare earth composite layer, the prepared encapsulation film exhibits excellent absorption characteristics in the <500 nm band, and can achieve <10 nm absorption under a radiative flux of 1000 lm. -6 With spectral absorption of W / nm, it reduces the potential damage to semiconductor microfabrication and sensitive optical components, which helps to improve product yield and the stability of optical systems during chip manufacturing.

Claims

1. A flexible rare-earth composite encapsulation film for high-spectral-purity yellow light illumination, characterized in that, The encapsulation film, from the light-incident side to the light-outcident side, comprises a rare-earth fluorescent layer, a rare-earth functional layer, and an impedance matching layer in sequence. The rare earth fluorescent layer comprises rare earth phosphor and a polymer film-forming material, wherein the rare earth phosphor contains rare earth ions and a matrix, and the rare earth ions are selected from yttrium (Y). 3+ lanthanum (La) 3+ ), Praseodymium (Pr 3+ ), samarium (Sm 3+ Europium (Eu) 3+ ), gadolinium (Gd 3+ ) or terbium (Tb 3 + At least one of the following: the matrix is ​​selected from at least one of aluminates, silicates, titanates, vanadates, tungstates, phosphates, nitrides, or fluorides; The rare earth functional layer comprises rare earth oxide nanoparticles and a polymer film-forming material. The rare earth oxide nanoparticles are selected from at least one of cerium oxide, yttrium oxide, samarium oxide, gadolinium oxide, or europium oxide, and the particle size of the nanoparticles is 80-120 nm. The impedance matching layer is formed by combining inorganic nanoparticles with different refractive indices with a polymer film-forming material, wherein the inorganic nanoparticles are selected from at least one of TiO2, SiO2 or ZrO2.

2. The encapsulation film according to claim 1, characterized in that, The rare earth phosphor has a mass fraction of 0.1%-10% and an emission wavelength range of 500-700 nm.

3. The encapsulation film according to claim 1, characterized in that, The impedance matching layer contains 0.01%-0.5% inorganic nanoparticles by mass; the impedance matching layer forms a stepped refractive index gradient distribution along the light emission direction, with a refractive index range of 1.65-1.

20.

4. The encapsulation film according to claim 1, characterized in that, The polymeric film-forming material is selected from at least one of polyimide, polymethyl methacrylate, polyethylene terephthalate, polycarbonate, polyvinyl naphthalate, or fluorinated ethylene propylene copolymer.

5. A method for preparing a flexible rare-earth composite encapsulation film for high-spectral purity yellow light illumination as described in claim 1, characterized in that, Includes the following steps: S1 Preparation of rare earth fluorescent layer: Rare earth fluorescent powder and polymer film-forming material are mixed at a predetermined mass ratio, dispersant and solvent are added, and dispersion treatment is performed to obtain rare earth fluorescent paste; the rare earth fluorescent paste is coated on the surface of the substrate and thermosetting to obtain rare earth fluorescent layer; S2 Preparation of rare earth functional layer: Rare earth oxide nanoparticles and polymer film-forming materials are mixed at a predetermined mass ratio, and dispersant and solvent are added. The mixture is then dispersed to obtain rare earth functional slurry. The rare earth functional slurry is coated onto the surface of the rare earth fluorescent layer and then thermosetting to obtain the rare earth functional layer. S3 Preparation of impedance matching layer: Inorganic nanoparticles with different refractive indices are mixed with polymer film-forming materials to form multiple films with refractive index gradients. Layered coating is used to gradually reduce the refractive index along the film thickness direction. The layers are coated and thermally cured in sequence to obtain the impedance matching layer. Finally, the layers are composited to obtain the overall multilayer flexible rare earth composite encapsulation film.

6. The preparation method according to claim 5, characterized in that, The dispersant is selected from at least one of polycarboxylic acid ammonium salt, polyvinylpyrrolidone, polyacrylate, sodium dodecyl sulfate, or nonionic surfactant.

7. The preparation method according to claim 5, characterized in that, The solvent is selected from at least one of ethanol, isopropanol, propylene glycol methyl ether, cyclohexanone, butyl acetate, N,N-dimethylformamide, or N-methylpyrrolidone.

8. The preparation method according to claim 5, characterized in that, The dispersion process specifically involves first performing high-speed stirring at 500-1000 rpm for 10-20 min; then performing ultrasonic dispersion at 200-400 W power and 20-40 kHz frequency for 10-30 min.

9. The preparation method according to claim 5, characterized in that, The thermosetting includes hot pressing or hot air curing; the temperature is 80-100℃ and the time is 10-40 minutes.

10. The application of the composite encapsulation film according to any one of claims 1-4 or the preparation method according to any one of claims 5-9 in a high-spectral-purity yellow light illumination device.

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