JP2017506354A - Nanoparticle optical filtering method and apparatus - Google Patents

Abstract

Implementations of the invention relate to devices, systems, and methods that block, attenuate, or filter neurostimulatory wavelengths in the visible light spectrum to reduce or prevent symptoms associated with exposure to those wavelengths. To make an optical notch filter, nanoparticles of a predetermined composition, size, and structure are dispersed in a host medium, thereby attenuating only a narrow range of the visible spectrum. [Selection figure] None

Description

Cross-reference of related applications
[0001] This application claims priority to US Patent Application No. 14 / 542,564, entitled "NANOPARTIC LIGHT FILTERING METHOD AND APPARATUS", filed on November 15, 2014, which is This is a continuation-in-part of US Patent Application No. 14 / 542,478 entitled “NANOPARTICLE LIGHT FILTERING METHOD AND AND APPARATUS” filed on November 14, 2014. It claims priority and benefit to US Provisional Patent Application No. 61 / 904,861, entitled “NANOPARTICLE LIGHT FILTERING METHOD AND APPARATUS”. All of the above applications are incorporated herein by reference in their entirety.

  [0002] In general, the present invention relates to optical filtering. More particularly, the present invention relates to reducing physiological responses to specific wavelengths of light using notch filters containing nanoparticles.

  [0003] Various electromagnetic wave lengths can have physical effects on the human body. In particular, certain wavelengths in the visible spectrum are thought to adversely affect nerves when received by certain photoreceptors in the human eye. Unlike rods and cones in the human eye, melanopsin ganglion cells, also known as endogenous light sensitive retinal ganglion cells (ipRGC), are endogenous light sensitive cells contained within the retina. These cells are connected to specific pain pathways as well as to the suprachiasmatic nucleus. The thalamic pain pathway is thought to affect migraine. On the other hand, the interaction between ipRGC and upper visual cortex is involved in circadian rhythm synchronization.

  [0004] The interaction between melanopsin ganglion cells and brain pain pathways has been thought to be linked to photophobia. This is a physical sensitivity to light, not an unreasonable fear of light, in contrast to the general use of “phobia”. Photophobia has been linked to causing or exacerbating other light-sensitive, neurological symptoms such as migraine or blepharospasm and traumatic brain injury (TBI). There are several distinct benefits to blocking or attenuating the wavelengths of light associated with dawn. By reducing the sensitivity of sensitive people, migraine and other adverse health effects can be reduced or prevented.

  [0005] Circadian rhythm is the internal cycle of the body and is generally synchronized with the 24-hour day-and-night cycle of the Earth. Circadian rhythm is important for sleep, mood, and nutrition because this internal cycle determines how long you feel you need to sleep or eat. While circadian rhythms can be very helpful in keeping the body “on schedule”, it can also be problematic for those who do not want to keep the body on the local daylight schedule. For example, a person who travels frequently may be able to avoid the effect of jet lag by preventing changes in his circadian rhythm due to traveling to different places in a short time. Or, if you have a profession with a schedule that is not based on the time of daylight, you might want to avoid the effect of sunlight on your circadian rhythm. For example, a shift doctor working at night may want to tune his body to circadian rhythm during the time he is awake and active, regardless of light or darkness.

  [0006] The current method for blocking or attenuating bad neurostimulatory wavelengths is to wear a lens that attenuates light over most of the visible spectrum. However, this method has significant disadvantages because such lenses impair vision at low light settings and distort colors in almost all situations. It is preferred to attenuate light reaching the eye only within one or more narrow ranges that are considered to be neurostimulatory.

  [0007] Thus, there are a number of benefits to being able to achieve selective attenuation or filtering of the neurostimulatory wavelength of light.

  [0008] Implementations of the invention block, attenuate or filter neurostimulatory wavelengths in the visible light spectrum and reduce or prevent symptoms associated with exposure to those wavelengths. And methods are used to address one or more of the above and other problems in the art.

  [0009] In a first non-limiting embodiment that incorporates the present invention, the optical filter can include nanoparticles dispersed in a host medium. The host medium can then be placed on the substrate. The substrate can be transparent to light in the visible spectrum, so that the only attenuation of light is caused by the dispersion of nanoparticles in the host medium covering the surface.

  [0010] In a second non-limiting embodiment, a method of manufacturing an optical notch filter includes determining a desired center wavelength of a filter, determining a desired full width at half maximum of the filter, and a plurality of nanometers. Varying the size of the particles, the composition of the nanoparticles, and the composition of the host medium in which the plurality of nanoparticles are located. Filters can be manufactured by various deposition techniques including spin coating and dip coating.

[0011] In a third non-limiting embodiment, a method of reducing the frequency and / or severity of a lightning reaction includes receiving an amount of light over the entire visible spectrum.
[0012] Additional features and advantages of exemplary implementations of the invention will be set forth in the following detailed description, and in part will be apparent from the following detailed description, or such exemplary Can be learned by implementing various implementations. The features and advantages of such implementations may be realized and attained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features will become more fully apparent from the following detailed description and the appended claims, or may be learned by the implementation of such exemplary implementations described below.

  [0013] To illustrate the manner in which the above and other advantages and features of the present invention can be achieved, a more specific description of the invention briefly described above is provided by the present invention as illustrated in the accompanying drawings. Given by reference to the embodiment. For better understanding, like elements are designated by like reference numerals throughout the various accompanying drawings. Although some of the drawings may be schematic, at least some of the drawings may be drawn to scale. With the understanding that these drawings depict only typical embodiments of the invention and are therefore not to be considered as limiting the scope of the invention, the invention will be further illustrated by the use of the accompanying drawings. Describe and explain with characteristics and details.

[0014] FIG. 6 is a graph showing the melanopsin action potential response to the transmission characteristics of a typical FL-41 35 filter prescribed for some patients with a pathology related to photoreaction. [0015] FIG. 6 is a graph showing a typical human visual response spectrum for the transmission characteristics of a typical FL-41 35 filter prescribed for some patients with a medical condition related to photoreaction. [0016] FIG. 6 is a graph showing the melanopsin action potential response to the transmission characteristics of a typical FL-4155 filter prescribed to some patients with a pathology related to photoresponse. [0017] FIG. 6 is a graph showing a typical human visual response spectrum for the transmission characteristics of a typical FL-41 55 filter prescribed for some patients with a medical condition related to light response. It is a graph for demonstrating use of the nanoparticle for wavelength attenuation. [0018] Figure 6 is a simulated extinction spectrum for 40 nm spherical nanoparticles. [0019] FIG. 6 is a simulated extinction spectrum for 40 nm cubic nanoparticles. [0020] FIG. 6 is a simulated quenching spectrum for 40 nm tetrahedral nanoparticles. [0021] FIG. 6 is a simulated extinction spectrum for 40 nm octagonal nanoparticles. [0022] A simulated quenching spectrum for a 50 nm triangular nanoparticle with a thickness of 5 nm. [0023] FIG. 5 is a series of simulated extinction spectra for nanoparticles of a wide-angle rectangular prism with a width of 50 nm having different axial lengths. [0024] Figure 6 is a graph showing simulated quenching efficiency for spherical particles having different diameters. [0025] FIG. 1 is a schematic cross-sectional view illustrating one embodiment of an optical filtering device according to the present invention. [0026] FIG. 6 is a schematic cross-sectional view illustrating another embodiment of an optical filtering device according to the present invention. [0027] FIG. 5 is a graph showing transmission spectra measured for various immersion durations. [0028] FIG. 2 is a cross-sectional view and associated spectrum illustrating one embodiment of core-shell nanoparticles according to the present invention. [0029] FIG. 2 is a cross-sectional view and associated spectrum illustrating one embodiment of a metal nanoparticle according to the present invention. [0030] Figure 6 is a graph of simulated quenching efficiency for spherical particles dissolved in different media. [0031] Figure 7 is a graph of simulated quenching efficiency for various particles of alloying ratio. [0032] FIG. 6 is a flow diagram of one method for alleviating a medical condition associated with a photoreaction according to the present invention.

  [0033] One or more implementations of the invention may create lenses, filters, or other devices that block, attenuate, filter, or otherwise tune a particular wavelength of light reaching the human eye, Or about the method. In particular, the present invention is primarily concerned with the attenuation of neurostimulatory wavelengths that affect ganglion cells containing melanopsin in the retina of the eye. Ganglion cells containing melanopsin, also known as endogenous light-sensitive retinal ganglion cells or ipRGC, form the top layer of light-sensitive cells in the retina. When the neurostimulatory wavelength interacts with ipRGC, the transmission signal is sent to several locations in the brain, separate from the image processing center. Among these are pain centers in the thalamus, circadian rhythm control centers in the supraoptic nucleus, and neurons in the midline of the brain. The invention particularly relates to the filtering or attenuation of wavelengths that activate at least these nerve centers.

  [0034] The neurostimulatory wavelength can be adjusted near a light source or a receptor in the eye. For example, a coating or filter can be placed across the screen or lens with the light source to prevent the light source from emitting wavelengths. Alternatively or additionally, light that approaches an individual's eyes can be filtered by the individual, for example, by wearing glasses that filter or attenuate certain wavelengths. Environmental issues may affect which method is preferred at that time. In the workplace, the majority of neurostimulatory wavelengths can be generated simply by computer monitors placed in front of individuals. A person who is sensitive to a particular wavelength can sufficiently reduce his or her exposure to that light by applying the filter directly to the computer screen. Similarly, a coating can be deposited on a light bulb or window to attenuate the wavelength of the light source when indoors.

  [0035] However, in other circumstances, simply reducing the emission of a neurostimulatory wavelength in a point light source may not be sufficient to reduce an individual's exposure. For example, it may not be possible to reduce emissions from all light sources in a building, or the primary light source of a neurostimulatory wavelength may be natural light such as sunlight or ambient light, and is based on the light source The solution becomes impossible. In such a situation, a sensitive person can wear or otherwise use a filter near or near his ipRGC. The selective adjustment of the wavelength can be performed with a transparent surface. The filter can be integral to the lens, such as sunglasses, or simply a coating on the lens, such as a thin coating, can be applied to a conventional prescription lens used for vision correction. In that way, glasses or even contact lenses with the property of attenuating the neurostimulatory wavelength can be worn by the individual and virtually all light reaching the eye can be adjusted.

  [0036] FIG. 1 shows a graph 100 with an example of an action potential spectrum estimated for ipRGC. Filled points 102 on the graph 100 are response values experimentally measured with respect to wavelength, normalized to the maximum response, and the dashed line is a Gaussian distribution 110 that fits the response data. This Gaussian distribution 110 is not meant to represent the exact reaction spectrum of ipRGC, but is an approximation of the illustrated data set. It should be understood that a more rigorous data set may be available for the ipRGC reaction spectrum, and that the present disclosure is at least equally applicable to the rigorous reaction spectrum.

  [0037] FIG. 1 also shows the transmission feature 120 of the "FL-41 35" filter, which is a filter that is currently commonly prescribed to adjust the transmission of light to a person who is sensitive to sunlight in an indoor environment. The FL-41 35 filter is made by impregnating a material with an organic dye to reduce the transmission of light through the material. As shown in FIG. 1, this filter minimizes the amount of incident light transmitted at a wavelength of about 500 nm, and transmits less than 70% of incident light from 400 nm to 640 nm corresponding to purple to orange in the visible light spectrum. To. On the other hand, the photoreceptor in ipRGC falls below 5% response outside the range of 430 nm to 520 nm as shown. Thus, while the amount 130 of light perceived by ipRGC is significantly reduced by the FL-41 35 filter, the rest of the individual's vision is also compromised.

  [0038] This effect is more fully visualized in FIG. The graph 200 of FIG. 2 shows the effect of the transmission feature 120 of the FL-41 35 filter on the individual's approximate total visual response spectrum 210. The estimated effective visual response 230 is significantly affected over the full width of the spectrum. In total, the FL-41 35 filter blocks about 47% transmission of incident light within the entire visible spectrum. Blocking the entire visible light spectrum can lead to undesirable effects such as perceived color distortion and / or can reduce vision in low light situations to an unacceptable level for the user. In addition, the transmission reduction is spread across the spectrum, so the FL-41 35 filter is an undesirable option when considering the coverage for point sources.

  [0039] FIG. 3 shows a graph 300 with an example of an action potential spectrum 310 estimated for ipRGC suppressed by the transmission feature 320 of the FL-4155 filter. FL-41 55 is a variant of the FL-41 35 filter, in which the material is impregnated with a greater amount of dye that blocks transmission. While FL-41 55 blocks approximately 89% of light transmission within the range where melanopsin cells are active, the FL-41 55 filter can also be seen in FIG. Thus, approximately 81% of the total spectrum is blocked from passing through the material. Since the FL-41 55 filter transmits less light, the FL-41 55 filter is primarily prescribed for outdoor applications. However, this makes one of several drawbacks to the FL-41 filter noticeable. That is, with the attenuation of other parts of the spectrum, when moving from an indoor environment to the outdoors, the user changes the actual FL-41 filter from, for example, an FL-41 35 filter to an FL-41 55 filter. It means you have to. Other drawbacks include the aforementioned color distortion and safety issues in low light situations, the need to mix dyes with only certain types of plastics, and the difficulties associated with the uniformity of the coloring process. It is.

  [0040] Accordingly, it is desirable to make a filter that attenuates neurostimulatory wavelengths while minimizing spectral distortion. Additional constraints or other constraints on the filter design may be considered, including optimization methods.

  [0041] One method for evaluating the performance of an optical filter in the context of blocking light absorption by melanopsin cells is presented herein. The amount of light D received by the melanopsin cell can be expressed as follows.

  Where L is the optical spectrum (in terms of intensity, power, number of photons / second, etc.), T is the spectral transmittance of the filter located between the light source and the eye, and M is the normal of melanopsin Is a normalized action potential response spectrum, which is currently estimated from FIG. 1 as a Gaussian function centered at 480 nm with a full width at half maximum of 52 nm. In general, it is assumed that L = 1 in order not to limit the discussion to any particular light source, but analysis can be performed for any light source of known spectrum. A similar dose associated with the visual response spectrum can be calculated as follows.

  Where V represents the normalized visual response spectrum. The effect of an optical filter such as FL-41 tint is to reduce the dose, which is shown by obtaining the ratio of the dose calculated with the filter to the dose without the filter. Moreover, the performance index (FOM) for comparing the block of the melanopsin reaction and the block of the visual reaction spectrum can be defined as follows.

In the above equation, the value FOM> 1 may be desirable. For example, in the case of FL-41 tint, the value FOM may be approximately 1.
[0042] As shown in the FOM equation above, the value FOM increases as the spectrum of the notch filter more closely approximates the visual response spectrum of melanopsin and ipRGC. Compared to the _unfiltered light dose D _melan (T = 1), the numerator approaches 1 as the light dose D _melan received by the melanopsin cell approaches 0 when using the filter. Conversely, as the portion of the visible spectrum that the filter attenuates becomes smaller, the denominator approaches 0, so the value FOM becomes greater than 1. The value FOM> 1 reflects the preferential filtering wavelength in the melanopsin visual response spectrum for the rest of the visible spectrum.

  [0043] A notch or bandstop filter is a filter that passes most wavelengths or frequencies unchanged, but attenuates wavelengths in a narrow range to a very low level. A notch filter can be thought of as the inverse of a bandpass filter. A notch filter can have a high Q value, which corresponds to a narrow stopband. Optical filter technology can include dielectric multilayers and nanoparticle coatings, among other technologies. Nanoparticle coatings can include metal nanoparticles, dielectric nanoparticles, semiconductor nanoparticles, or quantum dots, magnetic nanoparticles, core-shell particles, which act as one material and shell within the core. Made of materials. Nanoparticles can have a variety of shapes. The host material can comprise a polymer, sol gel, glass, or similar transparent or translucent material.

  [0044] The use of nanoparticles for wavelength attenuation has different properties than the thin film method because the nanoparticles scatter and absorb light regardless of the incident angle of light, as shown in graph 440 of FIG. 4A. . The variation between the measured transmittances of incident light at right angles to the surface of the filter at 450a, 450 ° at 30 °, and 450c at 60 ° is at least partially 8%, 12%, and This can be caused by a 31% double interface reflection. The double interface reflection coefficient can be calculated from the Fresnel equation. The calculated double interface reflection coefficient is consistent with the measured transmission spectrum. Since the nanoparticle notch filter works predictably regardless of the direction of the light source, it is well suited for general-purpose filtering such as eyeglass lenses. In addition, in order to achieve proper scattering and absorption of light, multiple parameters can be varied to optimize the range of attenuated wavelengths and the amount of attenuation, and adjust the notch filter for different wavelengths.

  [0045] Metal nanoparticles can be excited by incident light or other electromagnetic ("EM") radiation. As a result of the excitation of the metal nanoparticles, the metal nanoparticles can exhibit a collective oscillation of conduction electrons. The oscillation of the charge density of the conduction electrons is a localized surface plasmon (“LSP”). The LSP can enhance the localized electromagnetic field during resonance of multiple LSPs excited by a selective wavelength of incident light. The resonant behavior of multiple LSPs is known as localized surface plasmon resonance ("LSPR"). LSPR can provide large optical field enhancement and can result in strong scattering and / or absorption of incident wavelengths. For simplicity, the frequency at which LSPR occurs can be obtained by the following equation.

_Where ω _LSPR is the frequency of localized surface plasmon resonance, ω _p is the plasmon frequency of the metal, and ε _d is the dielectric constant of the environment surrounding the metal nanoparticles. The LSPR wavelength and peak width of the nanoparticle optical reaction may be affected at least by the nanoparticle composition, size, shape, dielectric environment, proximity to other nanoparticles, or combinations thereof.

  [0046] In LSPR, the enhanced localized field at the surface of the nanoparticles can result in scattering and absorption of incident light. Light scattering can be described as the redirection of light that occurs when an electromagnetic (EM) wave encounters an obstacle (ie, a nanoparticle). The absorption of light can be explained by the amount of incident light energy that is absorbed in the form of heat by the nanoparticles. The attenuation or loss of incident light due to a combination of light scattering and absorption is quenching. Dispersion of nanoparticles on or in a transparent medium can allow for increased quenching at various angles and amounts of incident light.

  [0047] The extinction spectrum of dispersed nanoparticles can be modeled by a combination of approximations. A quasi-static approximation will allow modeling of the scattering and absorption coefficients of spherical dimensions with a size of less than 1% of the wavelength of the incident light. Mie scattering theory (or Mie theory) will provide an approximation of the scattering and absorption coefficients of nanoparticles of other shapes and / or sizes. Mie theory will provide a general framework that allows an accurate solution to the light scattering and absorption of spherical particles.

  [0048] As shown in FIGS. 5A-5F, the shape of the nanoparticles can affect its extinction spectrum. As shown in FIG. 5A, a spherical particle spectrum 510 calculated based on spherical silver (Ag) nanoparticles having a diameter of 40 nm is a single particle that allows optimization using size and composition changes. Because it has a narrow primary peak, it can have the most focused spectrum of the presented embodiments. However, combinations of other shaped particles can be used to create the desired filter spectrum. In some embodiments, the quenching spectrum of a 40 nm spherical nanoparticle filter can be broadened by simply introducing, for example, 40 nm cubic nanoparticles or 40 nm octahedral nanoparticles. For example, FIG. 5B shows a cubic particle spectrum 520 calculated based on cubic Ag nanoparticles having a width of 40 nm. FIG. 5C shows a tetrahedral particle spectrum 530 calculated based on tetrahedral Ag nanoparticles having a width of 40 nm. FIG. 5D shows an octahedral particle spectrum 540 calculated based on octahedral Ag nanoparticles having a width of 40 nm along each side. In other embodiments, secondary peaks can be introduced at longer wavelengths, for example, by introducing triangular plate-like nanoparticles. FIG. 5E shows a triangular particle spectrum 550 calculated based on triangular plate-like Ag nanoparticles having a width of 40 nm and a thickness of 5 nm along the long side. The use of various particle shapes can be beneficial in tuning the spectrum of the nanoparticle filter. FIG. 5F shows the extinction spectrum of an Ag prism having a width of 50 nm with various axial lengths. The longest axial length results in the longest wavelength extinction spectrum 560, the intermediate axial length results in the intermediate wavelength extinction spectrum 562, and the shortest axial length corresponds to the shortest wavelength extinction spectrum. 564.

  [0049] FIG. 5G shows simulated quenching spectra for spherical particles using Mie scattering theory for 20 nm, 60 nm, 120 nm, and 240 nm Ag particles. As the diameter of the spherical nanoparticle increases, the spectral response shifts red (moves towards longer wavelengths), the peaks become wider, and higher order resonance modes can become more pronounced at shorter wavelengths. . When the particle size is equivalent to the wavelength of light, the spectral position of the LSPR can shift red with respect to the position predicted by electrostatic theory. Particles with dimensions that are closer to the incident wavelength dimension of the light may further result in inhomogeneous polarization of the nanoparticles via a delayed field because the incident EM field is not continuous throughout the spherical particle. The inhomogeneous polarization of the nanoparticles may result in excitation of higher order resonance modes 570 that can be seen in FIG. 5G. Therefore, it is beneficial to use particles having a diameter of less than about 100 nm, and it is more preferred to use nanoparticles having a diameter of less than about 80 nm.

  [0050] The surrounding host material may also affect the nanoparticle dispersion and the extinction spectrum of the associated optical filter. For example, the scattering coefficient may be proportional to the relative refractive index of the host material. The position of the extinction spectrum may depend at least in part on the dielectric constant of the host material. As the refractive index of the host material with embedded nanoparticles is increased, the spectral position of the LSPR shifts red, which can result in a more narrow and larger extinction coefficient.

  [0051] In one embodiment, a filter according to the present invention may use nanoparticles that absorb or reflect light within a narrow range, effectively blocking only that range of wavelengths. In one embodiment, the nanoparticles can be dispersed in a bulk transparent host material. In another embodiment, the nanoparticles can be dispersed in a transparent host material that is deposited as a coating on the substrate. The substrate can be transparent as well. For example, as shown in FIG. 6, the nanoparticles 620 may be dispersed in the host material 610, or the nanoparticles 720 were deposited on the surface of the substrate 750, as shown in FIG. It may be suspended in coating 710.

  In FIG. 6, nanoparticles 620 are shown suspended in host material 610. Host material 610 is normally transparent to the visible spectrum. Thus, the host material 610 itself does not attenuate visible light at all, allowing full or nearly complete transmission of the visible spectrum. Thus, the only effect on the light that attempts to pass through the host material 610 is due to the nanoparticles 620. In some embodiments, the nanoparticles 620 can be distributed substantially uniformly throughout the host material 610. In other embodiments, the nanoparticles 620 may agglomerate, resulting in a non-uniform distribution. For example, Ag nanoparticles can agglomerate in solution to form nanoparticle clusters, which effectively act as larger particles and affect LSPR behavior. Nanoparticles 620 can include a deagglomeration coating thereon to limit nanoparticle aggregation. The solution in which the nanoparticles 620 are dispersed can also include a deflocculating agent.

  [0053] Similarly, as shown in FIG. 7, the host material can be a coating 710, which, along with the substrate 750, can be substantially transparent to the visible spectrum. In any situation, the host material 610, coating 710, substrate 750, or similar structure can be transparent or have independent light filtering or blocking features. The nanoparticles 720 may aggregate together during the deposition of the nanoparticles 720 and the coating 710 to the substrate 750, or may otherwise cluster. In order to limit or even prevent clustering of nanoparticles 720, coating 710 may be applied as a thin film. In some embodiments, a thin film coating 710 may be applied to the substrate 750 by spin coating. Spin coating allows for uniform thickness deposition of coating 710 and nanoparticles 720 across the entire surface of substrate 750. In other embodiments, the coating 710 may be applied to the substrate 750 by dip coating.

  [0054] Spin coating creates a thin, substantially uniform coating 710 by rotating the substrate 750 during the coating 710 deposition. The rotation of the substrate will move the fluid coating 710 (and suspended nanoparticles 720) in a circular motion. The circular motion provides inertia to the coating 710 and suspended nanoparticles 720, which pushes the coating 710 and suspended nanoparticles 720 radially outward from the axis of rotation. The outwardly applied force (commonly known as “centrifugal force”) can be obtained by the following equation:

F _c = m × r × ω ²
Where F _c is the centrifugal force, m is the mass of the coating, r is the distance from the axis of rotation, and ω is the angular velocity in radians per second. The thickness of the coating 710 will decrease with increasing force and will therefore decrease with respect to the square of the mass and angular velocity.

  [0055] Dip coating creates a thicker coating 710 than spin coating by immersing the substrate 750 in a solution containing suspended nanoparticles 720 for a period of time and then withdrawing the substrate 750 from the solution. Can do. The thickness of the coating will depend at least in part on the duration of immersion, the withdrawal rate of the substrate 750, and the viscosity of the solution. For example, by making the immersion in the solution longer, the coating 710 formed on the base material 750 can be made thinner. The concentration of nanoparticles 720 in the coating 710 will increase as the immersion time becomes longer. In another example, a higher extraction rate can reduce the thickness of the coating 710 on the substrate 750.

  [0056] As shown in FIG. 7A, when using Ag nanoparticles having a major dimension of about 70 nm by way of example and not limitation, the overall transmittance of the filter increases as the duration of immersion increases. By making the coating 710 thinner, it becomes possible to increase the proportion of incident light to be transmitted. FIG. 7A shows transmission spectra of glass slides immersed for 10 seconds, 30 seconds, 60 seconds, and 120 seconds in an Ag nanoparticle solution in which PVA is dissolved. Ag nanoparticles suspended in solution can be about 70 nm in diameter. In other embodiments, the nanoparticles will have other diameters and will exhibit similar behavior. The 10 second soak curve 760a will result in a lower overall transmission of light through the filter. The overall transmission will increase and the 120 second immersion curve 760b will transmit more overall light.

  [0057] In one embodiment, in a conventional sunglasses lens or the like, the nanoparticle coating intended to tune the neurostimulatory wavelength to reduce light transmission comprises a material, coating, or dye It can be beneficial to place it in or on the surface of the substrate. In such a situation, the dye can be selected independently of the property that modulates its neurostimulatory wavelength, and the laminated structure still provides the aforementioned neurological benefits. In another embodiment, the material, coating, or substrate material can include other desired additives, such as photochromic components. For example, this can result in a lens for spectacles that can change its transmission characteristics over part or substantially all of the visible spectrum while maintaining optimal attenuation of the neurostimulatory wavelength. Such lenses are therefore suitable for indoor or outdoor use.

  [0058] Also, FIGS. 6 and 7 show, respectively, incident light 630, 730 and simulated by spectrum representing sunlight at sea level for a host material 610 having suspended nanoparticles 620 and a coating 710 having nanoparticles 720, respectively. Graphs 600 and 700 of transmitted light 640 and 740 are shown. In this example, the nanoparticles scatter and / or absorb wavelengths in the range of 480 nm. In one embodiment, the optical notch filter can attenuate a target wavelength, such as 480 nm, and a wavelength about 25 nm before and after the target wavelength, where the target wavelength is about 50 nm full-width half-width (“FWHM”). maximum). In another embodiment, the notch filter can have a FWHM of about 50 nm to about 80 nm. In yet another embodiment, the notch filter can have a FWHM of less than about 100 nm. 480 nm is the wavelength that produces the maximum response from ipRCG, but dispersed nanoparticles can be similarly tuned for transmission of other wavelengths such as 590 nm or 620 nm. In one embodiment, the nanoparticles may have a major dimension of less than about 80 nm. In another embodiment, the nanoparticles may have a major dimension of less than about 72 nm. In yet another embodiment, the nanoparticles may have a major dimension of less than about 50 nm.

[0059] Referring now to FIG. 8, a core-shell nanoparticle 800 having an inner core 810 with an outer shell 820 is shown. Although the illustrated core-shell nanoparticles 800 are substantially spherical, in other embodiments, the core-shell nanoparticles have a cross-section that includes a circle, oval, rectangle, hexagon, octagon, or other polygon. Can have. The core and shell of the nanoparticles can have different compositions. In some embodiments, the inner core 810 can include one or more materials selected from the group consisting of metals, dielectric materials, and magnetic materials. The inner core 810 can include a noble metal, a transition metal, a post transition metal, an alkali metal, or an alkaline earth metal. The noble metal can be silver, gold, or platinum. The transition metal can be copper, titanium, or zinc. The post transition metal can be aluminum or gallium. The alkali metal can be sodium or potassium. The alkaline earth metal can be magnesium. Inner core 810 may also include two or more alloys of the aforementioned metals. In other embodiments, the inner core 810 may comprise a metal oxide comprising SiO ₂ , TiO ₂ , Al ₂ O ₃ , or ZnO.

[0060] Similarly, any of the aforementioned metals, dielectric materials, or magnetic materials are suitable as materials for the outer shell 820 as well. In some embodiments, the core can include SiO ₂ and the outer shell 820 can include silver (Ag). In other embodiments, the core-shell nanoparticles 800 include SiO ₂ and Ag, where SiO ₂ is the material of the inner core 810 and may occupy about 58% of the radius. The remaining 42% of the radius is Ag outer shell 820. However, the core-shell nanoparticles 800 may have other ratios between the inner core 810 and the outer shell 820 to tune the spectral response. In yet another embodiment, the inner core 810 may have a thickness of 16 nm. In yet further embodiments, the outer shell 820 may have a thickness of 8 nm.

  [0061] The extinction spectrum of the spherical nanoparticles can be calculated using Mie scattering theory, which depends in part on the radius of the core-shell nanoparticles 800. Thus, as described in connection with FIG. 5G, the radius of the nanoparticles can be used to fine tune the spectral response 830 of the nanoparticle filter. In some embodiments, assuming that the composition of the nanoparticles in the optical filter is constant, the quenching spectrum of the filter can shift toward longer wavelengths as the average radius of the nanoparticles increases. . In other embodiments, a larger average radius of the nanoparticles can be used to attenuate a larger portion of the light.

  [0062] In contrast to FIG. 5G, FIG. 8 illustrates the effect of changing the core radius of the core-shell nanoparticles 800. FIG. The notch position will shift little or no, but only the amplitude and distribution of the curve will shift near the peak position. Such a change in the distribution of material within the core-shell nanoparticles 800 can change the amount of light attenuated without requiring a media change or a change in the size of the core-shell nanoparticles 800. Can be optimized.

  [0063] Furthermore, the density of the nanoparticles suspended in the material can be selected to achieve a desired rate of decay of the neurostimulatory wavelength. One skilled in the art will appreciate that higher density nanoparticles provide a faster decay rate, but that further enrichment only results in resonance coupling between the particles. To prevent nanoparticle aggregation, the nanoparticles can include an anti-agglomeration shell or coating, such as polyvinylpyrrolidone, as described in connection with FIG.

[0064] The nanoparticles can be in a dissolved state in the host medium. The host medium can be a polymer suspension such as polyvinyl acetate, polymethyl methacrylate (PMMA), sol gel, or similar medium. In one embodiment, the concentration of nanoparticles dissolved in the host medium is about 15% by weight. In another embodiment, the concentration of nanoparticles dissolved in the host medium is about 20% by weight. In yet another embodiment, the concentration of nanoparticles dissolved in the host medium is about 7.05 × 10 ¹⁰ particles per cubic centimeter. In a further embodiment, the nanoparticles dissolved in the host medium may have a molecular weight of 30,000 to 100,000.

  [0065] In addition, the medium selected for the bulk or coating material in which the nanoparticles are suspended will shift the reaction spectrum. Referring now to FIG. 9, a nanosphere 900 comprising a single material 910 having a radius 920 is shown. In one embodiment, the nanosphere 900 can include one or more of the materials described for use in the inner core 810 of the core-shell nanoparticles 800 described above. The spectral response of 15 nm Ag nanospheres 930a and 25 nm Ag nanospheres 930b depends on the refractive index of both the bulk material or the coating medium in which the nanospheres are suspended. FIG. 9A shows the effect of medium refractive index on the simulated spectral response of spherical 30 nm Ag nanoparticles. As the refractive index of the medium increases, the wavelength attenuated by the notch filter becomes longer. In various embodiments, the refractive index of the medium can be less than about 1.5, about 1.5, or greater than about 1.5. As discussed above, increasing the radius of the nanosphere results in increased attenuation, but also shifts the spectral response. However, by changing the refractive index of the medium, it is possible to shift the spectral response back towards the desired wavelength, in this case 480 nm.

  [0066] Nanoparticles 900 having a single radius 910 (ie, substantially homogeneous nanoparticles) can exhibit various extinction coefficients. By changing the alloying ratio of the material in the nanoparticles 900 while maintaining a constant radius 910, the wavelength attenuated by the notch filter can be shifted. For example, FIG. 9B is a graph showing the effect of variation in the alloying rate of nanoparticles containing silver-aluminum alloy metal (AgXXAlXX, where XX is the compositional rate). The extinction coefficient for each composition can shift blue as the proportion of aluminum in the alloy increases. For example, the curve 950a for Ag90Al10 has a maximum at about 400 nm, and the curve 950b for Ag50Al50 has a maximum at about 320 nm.

  [0067] These examples have been described so far for optical notch filters that include a single-mode distribution of nanoparticles to achieve high Q values and attenuate single wavelengths or narrow ranges of wavelengths. It will be understood that. However, the use of an optical notch filter is not limited to one wavelength, and it is possible to use nanoparticles of different shapes, compositions, or sizes for selective attenuation of two or more wavelengths.

  [0068] This can be achieved by homogenous dispersion of nanoparticles having two or more compositions, shapes, and / or sizes, or by stacking coating materials having one or more specific species of nanoparticles. Can do. For example, a filter with 25 nm Ag nanospheres in FIG. 8 can be made to attenuate light in the 480 nm range of the spectrum, while other nanoparticles attenuate light in another range of the spectrum. Each of these species is homogeneously dispersed. Alternatively, a first coating suitable for attenuating light in a first range, such as the 480 nm range, can be applied to the surface of the spectacle lens and then attenuates the light in the second range. A suitable second coating can be applied to another surface of the lens or can be laminated over the first coating. Each coating, whether applied alone or in combination, can have a thickness greater than about 5 μm. In another embodiment, the coating can have a thickness of about 6 μm. In another embodiment, the coating can have a thickness of about 11 μm.

  [0069] The thickness of the coating and the distribution of nanoparticles within the coating can be controlled by the coating deposition method. In one embodiment, depositing the coating can include a spin coating step. In another embodiment, coating deposition can include a dip coating step. In yet another embodiment, the deposition of the coating can include a deagglomeration step, which can itself include ultrasonic dispersion.

  [0070] FIG. 10 shows a method 1000 of making an optical notch filter to reduce or alleviate symptoms associated with exposure to a neurostimulatory wavelength. As shown, the method includes at least obtaining a host medium 1010 and embedding or applying on the host medium nanoparticles that filter light corresponding to the action potential spectrum of the melanopsin pathway. 1020. Additional steps of the method may include determining the desired center frequency of the filter, determining the desired full width at half maximum of the filter, or changing the size of the plurality of nanoparticles or nanoparticle compositions. it can. In addition, the manufacturing process can include changing the composition of the host medium. Depending on the host medium used, the manufacturing method can optionally include removing air bubbles from the solution of the host medium and nanoparticles.

  [0071] The articles "a", "an", and "the" are intended to mean that one or more of the elements in the foregoing description are present. The terms “comprising”, “including”, and “having” are intended to be open and mean that there may be additional elements other than the listed elements. The Additionally, references to “one embodiment” or “an embodiment” of the present disclosure are to be interpreted as excluding the existence of further embodiments that also incorporate the features described therein. It should be understood that it is not intended to be done. As will be appreciated by those skilled in the art encompassed by embodiments of the present disclosure, the numbers, percentages, ratios, or other values described herein include those values and are also “approximately ( "about" or "approximately" is intended to include other values within the range of the value. Accordingly, the stated value should be construed broadly enough to encompass values that are sufficiently close to the stated value to perform at least the desired function or achieve the desired result. The stated value includes at least the expected variation in a suitable manufacturing or fabrication process and is within 5%, 1%, 0.1%, or 0.01% of the stated value. Values within the range of.

  [0072] In light of the present disclosure, various modifications, substitutions, and alterations disclosed herein do not depart from the spirit and scope of the present disclosure and equivalents without departing from the spirit and scope of the present disclosure. Those skilled in the art will appreciate that these can be added to the embodiment. Equivalent structures including functional “means plus function” claims perform the described functions, including both structural equivalents that operate similarly and equivalent structures that provide the same function As intended to encompass the structures described herein. Applicant's express intent is not to seek means-plus-function or other functional claims against any claim, except for claims where the word “means for” is indicated with the relevant function. is there. Each addition, deletion, and modification to an embodiment falling within the meaning and scope of the claims is intended to be covered by the claims.

  [0073] As used herein, the terms "approximately", "about", and "substantially" can similarly perform a desired function or achieve a desired result. , Represents an amount close to the amount. For example, the terms “approximately,” “about,” and “substantially” are in the range of less than 5%, less than 1%, less than 0.1% of the stated amount. And amounts within the range of less than 0.01%. Further, it should be understood that any direction or reference system in the above description is merely a relative direction or motion. For example, any reference to “up” and “down” or “above” or “below” merely describes the relative position or motion of the elements concerned. is there.

  [0074] The present disclosure may be implemented in other specific forms without departing from the spirit or features of the present disclosure. The described embodiments are to be considered exemplary rather than limiting. The scope of the disclosure is, therefore, indicated by the appended claims rather than by the foregoing description. Any equivalent meanings and changes within the scope of the claims shall be embraced within the scope of the claims.

Claims (20)

A light transmissive substrate;
A host material,
A plurality of nanoparticles incorporated into the host material and attached to the substrate as a coating, the plurality of nanoparticles having an average major dimension of less than 120 nm;
The substrate, the host material, and the nanoparticles cooperate to provide an attenuation spectrum having a predetermined center wavelength, the attenuation spectrum having a full width at half maximum of less than 100 nm near the predetermined center wavelength;
Optical filter.   The optical filter according to claim 1, wherein the nanoparticles include at least one material selected from the group consisting of noble metals, transition metals, post-transition metals, alkali metals, and alkaline earth metals.   The optical filter according to claim 2, wherein the noble metal is selected from the group consisting of silver, gold, and platinum.   The optical filter according to claim 1, wherein the nanoparticles have a spherical shape.   The optical filter of claim 1, wherein the plurality of nanoparticles comprises at least one core-shell nanoparticle having an outer shell and an inner core.   6. The optical filter of claim 5, wherein the shell of the core-shell nanoparticles has a thickness of 8 nm.   The optical filter of claim 5, wherein the inner core of the core-shell nanoparticles is formed from a metal oxide.   The optical filter according to claim 1, wherein at least one of the plurality of nanoparticles incorporated in the host material has a molecular weight of 30,000 to 100,000.   The optical filter according to claim 1, wherein at least one nanoparticle of the plurality of nanoparticles has an anti-aggregation shell containing polyvinylpyrrolidone.   The optical filter of claim 1, wherein the host material comprises polyvinyl acetate.   The optical filter of claim 1, wherein the host material has a predetermined refractive index greater than 1.5.   The optical filter of claim 1, wherein the coating has a thickness greater than 5 μm. A method of manufacturing an optical notch filter, comprising:
Determining a desired center wavelength of the filter;
Determining a desired full width at half maximum of the filter;
Manufacturing the filter by varying the size of a plurality of nanoparticles, the composition of the nanoparticles, and the composition of a host medium.   14. The method of claim 13, wherein the nanoparticles are incorporated into a host material and the step of manufacturing the filter further comprises changing the concentration of the nanoparticles in the host material.   The method of claim 13, wherein manufacturing the filter further comprises a spin coating step.   The method of claim 13, wherein manufacturing the filter further comprises a dip coating step.   The method of claim 13, wherein the nanoparticles are core-shell nanoparticles having an inner core and an outer shell.   The method of claim 17, wherein manufacturing the filter by changing the size of the nanoparticles further comprises changing the size of the core and the shell. A method of reducing the frequency and / or extent of photophobia, including migraine, photosensitivity associated with traumatic brain injury, and blepharospasm, or adjusting the circadian cycle,
Receiving an amount of light over the entire visible spectrum;
Introducing into the light path an optical filter comprising a plurality of nanoparticles dispersed in a host material;
Attenuating the portion of the spectrum associated with absorption by melanopsin ganglion cells so that a performance index greater than 1.5 is achieved;
The method wherein the performance index is defined as the ratio of light attenuation weighted over the action potential spectrum of the melanopsin pathway and light attenuation weighted over the visual spectrum response.   20. The method of claim 19, wherein the plurality of nanoparticles exhibit localized surface plasmon resonance when exposed to the portion of the spectrum associated with absorption by melanopsin ganglion cells.

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