Simple natural light mimics

Abstract

An artificial illumination light source to mimic natural light' s engagement of an organism's visual pigments using a small set of wavelengths is provided. In the case in which the organism is a mouse or human, mimicking daylight' s engagement of the visual pigments in the eye may be accomplished with as few as two peak wavelengths, including a first "short" wavelength and a second "medium" wavelength. The artificial illumination source may include two discrete narrow-band light sources to generate the two peak wavelengths. The peak wavelengths may be generated with unequal intensities to further mimic natural light, including daylight.

Description

[0001] SIMPLE NATURAL LIGHT MIMICS

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] The present application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 636,662, filed April 19, 2024 under Attorney Docket No. C1233.70287US00, and entitled “SIMPLE NATURAL LIGHT MIMICS” which is hereby incorporated by reference herein in its entirety.

[0004] FEDERALLY SPONSORED RESEARCH

[0005] This invention was made with government support under Grant Nos. EY023648, EY025555, EY032731, EY030628, and EY034089, awarded by the National Institutes of Health. The Government has certain rights in the invention.

[0006] BACKGROUND

[0007] Non-human and human subjects are often exposed to various types of artificial lighting in the environment as well as for housing, treatment, and scientific study. Artificial lighting is also used for the treatment and study of non-human and human tissues.

[0008] SUMMARY

[0009] Some embodiments are directed to an apparatus, including an artificial illumination light source configured to mimic how natural light engages an organism’ s visual pigments by producing an output spectrum having no more than three peak wavelengths. The artificial illumination light source may include only two wavelengths: a first discrete narrow-band light source emitting light at a first peak wavelength and a second discrete narrow-band light source emitting light at a second peak wavelength.

[0010] Some embodiments are directed to a method of illuminating a set of visual pigments with an artificial light source, the method including controlling emission of light from a light source to emit light toward an organism such that the light exhibits a spectrum having no more than three peak wavelengths.

[0011] BRIEF DESCRIPTION OF DRAWINGS

[0012] The accompanying drawings are not intended to be drawn to scale. For purposes of clarity, not every component may be labeled in every drawing. In the drawings:

[0013] FIG. 1 A illustrates an example path of light from a light source to the retina of a mouse in a lab setting. FIG. IB illustrates normalized plots of the intensity versus the wavelength of light as it impinges upon the cornea of the eye of a mouse.

[0014] FIG. 1C illustrates normalized plots of the intensity versus the wavelength of daylight as it impinges upon the retina of a mouse.

[0015] FIG. ID illustrates the levels of engagement (of various visual pigments in the retina of a mouse by incident light.

[0016] FIGs. 1E-1G illustrate data of the same kind as in FIGs. IB- ID but for a human, and include the situations of both a daylight mimic having two peak wavelengths and a daylight mimic having three peak wavelengths.

[0017] FIG. 2 illustrates an example embodiment of a system for illuminating a set of visual pigments of a subject with an artificial light source to mimic daylight.

[0018] FIG. 3 illustrates a method of illuminating a set of visual pigments in a mouse with an artificial light source to mimic daylight, according to some embodiments.

[0019] FIG. 4 illustrates the relative root-mean-square error of a daylight mimic for a mouse as a function of two peak wavelengths used as the daylight mimic, according to some embodiments.

[0020] DETAILED DESCRIPTION

[0021] The visual system is important for perception (“image” vision). It also regulates “nonimage” visual processes that include circadian rhythms, sleep, mood, cognition, and development. These processes are vital. For example, the circadian rhythm regulates activity patterns in practically all tissues of the body, and circadian dysregulation is linked with cancer, cardiovascular disease, metabolic disorder, mood dysregulation, and other ailments. The principal regulator of the circadian clock is light. To ensure that perception and non-image vision develop and function normally, one requires light that influences the organism naturally. However, the artificial light used for, for example, housing, treatment and scientific study generally is mismatched to the natural lighting under which organisms evolved and continue to require.

[0022] Aspects of the present technology relate to an artificial daylight mimic for non-human and human subjects. “Daylight” as used herein encompasses “sunlight.” The inventor(s) has appreciated that non-human and human subjects process light, including daylight, differently from one another. An example of a subject described throughout this disclosure is a mouse, although it should be appreciated that some of the aspects of the technology described herein apply to other non-human and human subjects. The inventor(s) has appreciated that indoor lighting, such as lab lighting, conventionally includes wavelengths that do not stimulate light receptors in mice in the same way as natural light. Thus, a lab environment utilizing conventional light sources does not represent a natural setting for a mouse. As a result, any attempt to assess mouse behavior or response to a given stimuli may be inaccurate owing to the mouse being in an unnatural setting and its visual system potentially operating in an unnatural manner. Similarly, raising mice in such a setting may itself lead to mice whose perception and non-image vision do not develop and function normally, such that the mice may not behave naturally, thus undermining efforts to accurately assess how a healthy mouse will respond to a given stimulus.

[0023] The inventor(s) has determined that a light source may be created for use in lab settings or other controlled environments that mimics daylight from the perspective of the mouse. The light source may have a small number of peak wavelengths delivered at relative intensities selected to account for the photo-response of the mouse. Thus, in some embodiments, a daylight mimic is provided for mice. The daylight mimic comprises a light source having two peak wavelengths. One peak wavelength is between approximatley 395 nm and approximately 405 nm, for example at 402.4 nm (the theoretical ideal) or 405 nm and the other peak wavelength is between approximately 495 nm and approximately 535 nm, for example at 510.8 nm (the theoretical ideal) or 531 nm. The shorter wavelength is delivered at an intensity multiple times that of the longer wavelength. In some embodiments, the shorter wavelength is provided with between 0.5 to five fold the intensity of the longer wavelength. In at least some embodiments, the daylight mimic includes only the two peak wavelengths noted above and no additional peak wavelengths.

[0024] Some embodiments are directed to a method of illuminating a set of visual pigments with an artificial light source, the method comprising emitting light with a minimum number of wavelengths in ratios that mimic daylight. In some embodiments, the method comprises adjusting the ratios of the minimum number of wavelengths to compensate for the light path traversed by the light prior to reaching the visual pigments. Visual pigments may include but are not limited to rhodopsin in rods, ultraviolet wavelength sensitive (UWS) pigments in cones, short-wavelength sensitive (SWS) pigments in cones, medium-wavelength sensitive (MWS) pigments in cones, long-wave sensitive (LWS) pigments in cones, melanopsin’s three stable conformations (extramelanopsin, “MelE”; metamelanopsin, “MelM”; and melanopsin, “MelR”), and neuropsin (Opn5). For example, the light path traversed may include optics of an eye and / or material of a cage. In some embodiments, the method comprises adjusting the ratios of the minimum number of wavelengths to mimic a particular spectrum of daylight or other natural light. In some embodiments, the method comprises setting the overall intensity of light emitted by the artificial light source to provide a desired range, while maintaining the ratios of the minimum number of wavelengths.

[0025] FIG. 1 A illustrates an example path of light from a light source to the retina of a mouse in a lab setting. Incident light 100 having two peak wavelengths 101 and 102 is emitted by the light source (not shown in FIG. 1A) and passes through a cage 107 before entering the eye 106 of a mouse 105 via the cornea. There, the light passes through the lens 108 and impinges upon the retina 104, engaging the visual pigments 103 (including inside rod and cone photoreceptors) of the eye 106.

[0026] Visual pigments 103 may be located in photoreceptors such as rods, cones, and ipRGCs of retina 104. In the case of a mouse, such as mouse 105, the visual pigments 103 include rhodopsin in rods, ultraviolet-wavelength sensitive (UWS) and medium-wavelength sensitive (MWS) pigments in cones, and melanopsin in ipRGCs. Notably, melanopsin has several states with distinct spectral sensitivities.

[0027] The inventors have appreciated that mimicking daylight for the visual pigments in a mouse eye may be accomplished with as few as two wavelengths, including a first “short” wavelength between approximately 395 nm and approximately 405 nm, for example at 402.4 nm (the theoretical ideal) or 405 nanometers (nm) and a second longer (sometimes referred to herein as “medium”) wavelength between approximately 495 nm and approximately 535 nm, for example at 510.8 nm (the theoretical ideal) or 531 nm. In some embodiments, then, a daylight mimic (e.g., for a mouse) includes only two peak wavelengths, such as those wavelengths listed above.

[0028] The inventors have further appreciated that the relative intensities of the peak wavelengths of incident light can impact the effectiveness of a light source as a daylight mimic depending on the path that light takes to the photoreceptors, and in particular that providing a greater intensity of the shorter or longer wavelength may improve the function of the light as a daylight mimic. The relative intensity of the short wavelength to the longer wavelength may be between 0.5:1 and 5:1. In the example of two peak wavelengths at 402.4 nm and 510.8 nm, implementing an intensity ratio of 1.5:1 (with the light at 402.4 nm being 1.5 times more intense than the light at 510.8 nm) most effectively mimics daylight for a mouse in at least some embodiments. In another example, the shorter wavelength may be approximately 405 nm and the longer wavelength may be approximately 531 nm, and the relative intensity of the short wavelength to the longer wavelength may be between 0.5:1 and 5:1. FIG. IB illustrates normalized plots of the intensity versus the wavelength of light (in nm) as it impinges upon the cornea 109 of the eye 106 of mouse 105. In particular, the top panel of FIG. IB shows the intensity of different wavelengths of light included in daylight as it impinges upon the cornea 109 of eye 106 of mouse 105.

[0029] Meanwhile, the bottom panel of FIG. IB shows the intensity of each of peak wavelengths 101 and 102 as they impinge upon the cornea 109 of eye 106 of mouse 105. As described above in reference to FIG. 1A, in some embodiments, peak wavelength 101 is between approximately 395 nm and approximately 405 nm, for example at 402.4 nm (the theoretical ideal) or 405 nm, and peak wavelength 102 is between approximately 495 nm and approximately 535 nm, for example at 510.8 nm (the theoretical ideal) or 531 nm. The ratio of intensities between the two peak wavelengths has been adjusted so that the two peak wavelengths will engage the visual pigments 103 in the retina 104 of mouse 105 in the same way that daylight does. The ratio of intensities between peak wavelengths 101 and 102 as shown in the bottom panel of FIG. IB, which illustrates the scenario of one peak wavelength at 402.4 nm and another at 510.8 nm, may reflect adjustments made to account for subsequent passage of the impinging light through the ocular tissue of eye 106 of mouse 105, so that together the two peak wavelengths accurately mimic natural daylight. In the example embodiment illustrated in FIG. IB, the intensity of peak wavelength 101 is 1.5 times that of peak wavelength 102.

[0030] FIG. 1C illustrates normalized plots of the intensity versus the wavelength of daylight (in nm) as it impinges upon retina 104 of mouse 105. In particular, the top panel of FIG. 1C shows the intensity of different wavelengths of light included in actual daylight as it impinges upon retina 104 of mouse 105. The difference between the shapes of the plots in the top panels of FIG. IB and FIG. 1C results from the fact that the daylight spectrum is shaped as it passes through the ocular tissues of eye 106 before impinging upon retina 104.

[0031] Meanwhile, the bottom panel of FIG. 1C shows the intensity of each of peak wavelengths 101 and 102 as they impinge upon retina 104 of mouse 105. As described above in reference to FIG. 1 A, the example of the bottom panel of FIG. 1C illustrates a scenario in which peak wavelength 101 is at 402.4 nm and peak wavelength 102 is at 510.8 nm. The ratio of intensities between the two illustrated peak wavelengths has been adjusted so that the two-peak wavelengths will engage the visual pigments 103 in the retina 104 of mouse 105 in the same way that daylight does. Unlike in the case of FIG. IB, the light represented in FIG. 1C is incident directly upon the retina 104 of mouse 105 and thus does not pass through ocular tissues prior to reaching the visual pigments. Therefore, the ratio of intensities between the two peak wavelengths shown in the bottom panel of FIG. 1C does not reflect adjustments made to account for passage through ocular tissue. In the example embodiment illustrated in FIG. 1C, peak wavelength 101 is 402.4 nm and peak wavelength 102 is 510.8 nm and the intensity of peak wavelength 101 has been adjusted as compared to FIG. IB so that it is 1.1 times that of peak wavelength 102. This ratio mimics daylight for a mouse if the ocular tissue of the eye before the retina is not present.

[0032] FIG. ID illustrates the proportion of photon availability for the various visual pigments 103. Photon availability is the spectrum of light at the eye 106 of mouse 105 multiplied by the normalized absorption spectrum of a pigment 103 state and then integrated. The visual pigments for which the photon availability is shown in FIG. ID are ultraviolet-wavelength sensitive cone pigment (UWS), medium-wavelength sensitive cone pigment (MWS), melanopsin (MelE, MelM, and MelR), and rhodopsin. In particular, the top panel of FIG. ID indicates the photon availability of these pigments when natural daylight is incident upon eye 106. The bottom panel of FIG. ID indicates the photon availability of these pigments when peak wavelengths 101 and 102 are incident upon eye 106. A comparison of the top and bottom panels of FIG. ID shows that peak wavelengths 101 and 102 almost exactly mimic the visual pigment photon availability produced by daylight in eye 106 of mouse 105. Indeed, the measured deviation from daylight engagement was <1.6% for rhodopsin, cone pigments, and melanopsin. Two wavelengths also suffice to mimic daylight for trichromatic humans, with the deviation being <7.7% for rhodopsin, cone pigments and melanopsin.

[0033] Alternatively, the subject may not be a mouse, as daylight mimics according to various embodiments of the present technology may be tailored to a human or different non-human subject. FIGs. 1E-1G illustrate data of the same kind as in FIGs. 1B-1D but for a human, and include the situations of both a daylight mimic having two peak wavelengths and a daylight mimic having three peak wavelengths. In particular, the top panel of FIG. IE shows the intensity of different wavelengths of light included in daylight as it impinges upon the cornea 109 of eye 106 of a human. Meanwhile, the middle panel of FIG. IE shows the intensity of each of peak wavelengths at 461.3 nm and 547.4 nm as they impinge upon the cornea 109 of eye 106 of a human, representing a daylight mimic with two peak wavelengths. The bottom panel of FIG. IE shows the intensity of each of peak wavelengths at 452.4 nm, 515.2 nm, and 581.5 nm as they impinge on the cornea 109 of eye 106 of a human, representing a daylight mimic with three peak wavelengths.

[0034] The top panel of FIG. IF shows the intensity of different wavelengths of light included in actual daylight as it impinges upon retina 104 of a human for the same wavelengths as shown in FIG. IE. The middle panel of FIG. 1G shows the intensity of each of peak wavelengths at 461.3 nm and 547.4 nm as they impinge upon retina 104 of a human. The bottom panel of FIG. IF shows the intensity of each of peak wavelengths at 452.4 nm, 515.2 nm, and 581.5 nm as they impinge upon the retina 104 of a human.

[0035] FIG. 1G illustrates the proportion of photon availability for the various visual pigments 103 of a human. The visual pigments for which the photon availability is shown in FIG. 1G are short-wavelength sensitive pigment (SWS), melanopsin (MelE, MelM, and MelR), rhodopsin, medium-wavelength sensitive pigment (MWS), and long-wavelength sensitive pigment (LWS). In particular, the top panel of FIG. 1G indicates the photon availability of these pigments when natural daylight is incident upon eye 106 of a human. The middle panel of FIG. 1G indicates the photon availability of these pigments when peak wavelengths at 461.3 nm and 547.4 nm are incident upon eye 106 of a human, representing a daylight mimic with two peak wavelengths. The bottom panel of FIG. 1G indicates the photon availability of these pigments when peak wavelengths at 452.4 nm, 515.2 nm, and 581.5 nm are incident upon eye 106 of a human, representing a daylight mimic with three peak wavelengths.

[0036] Returning to FIG. 1A, in some embodiments, the light source may provide peak wavelengths 101 and 102 at a precise ratio of intensities to mimic natural daylight for a mouse. The correct ratio of intensities of peak wavelengths 101 and 102 will match daylight’s engagement of the visual pigments 103 of the photoreceptors in the retina 104 of the mouse 105, as shown in the right-most panel of FIG. 1 A. For example, as described above with reference to FIGs. 1B-1D, the correct ratio of intensities of peak wavelengths 101 and 102 may be anywhere between 0.5:1 and 5:1 depending on the optical path taken by peak wavelengths 101 and 102 before reaching visual pigments 103.

[0037] As shown in FIG. 1A, in some embodiments, prior to impinging on visual pigments 103 in retina 104, peak wavelengths 101 and 102 may pass through the eye 106 of mouse 105. The precise ratio of intensities between peak wavelengths 101 and 102 may need to be adjusted to account for their passage through the ocular tissues of eye 106, such that they still match daylight’s engagement of visual pigments 103, as described above in reference to FIG. 1C.

[0038] As shown in FIG. 1A, in some embodiments, prior to impinging on visual pigments 103 in retina 104 and passing through eye 106 of mouse 105, peak wavelengths 101 and 102 may pass through cage 107, which may house mouse 105 in a given experimental set-up or when the mouse is being raised. The precise ratio of intensities between peak wavelengths 101 and 102 may need to be adjusted to account for their passage through the cage material of cage 107, such that they still match daylight’s engagement of visual pigments 103. More generally, the ratio of intensities between peak wavelengths 101 and 102 may be adjusted for any optical path in front of the pigments, which may include materials involved in the experimental set-up and / or ocular tissues.

[0039] FIG. 2 illustrates an example embodiment of system 200 for illuminating a set of visual pigments with an artificial light source to mimic daylight and other natural light sources. System 200 includes a light source 210. In some embodiments, light source 210 may emit light that mimics the engagement by daylight of the visual pigments of a given organism. In some embodiments, light source 210 may do this by emitting light which includes a small number of peak wavelengths, and in some embodiments a minimal number of peak wavelengths to trigger the desired photo-response in the subject.

[0040] For example, light source 210 may be configured to emit light that mimics the engagement by daylight of the visual pigments of a mouse, which include rhodopsin in rods, ultraviolet-wavelength sensitive (UWS) and medium-wavelength sensitive (MWS) pigments in cones, and melanopsin (MelE, MelM, and MelR) in intrinsically photosensitive retinal ganglion cells (ipRGCs). In this case, light source 210 may emit light consisting of a set of two peak wavelengths, as described above in connection with FIG. 1A. The two peak wavelengths may include a wavelength between approximately 395 nm and approximately 405 nm, for example at 402.4 nm or 405 nm, and a wavelength between approximately 495 nm and approximately 535 nm, for example at 510.8 nm or 531 nm. In some embodiments, light source 210 may include a first discrete narrow-band light source 212 that generates light of a first peak wavelength, such as between approximately 395 nm and approximately 405 nm, for example at 402.5 nm (the theoretical ideal) or 405 nm, and a second discrete narrow-band light source 214 that generates light of a second peak wavelength, such as between approximately 495 nm and approximately 535 nm, for example at 510.8 nm (the theoretical ideal) or 531 nm. In some embodiments, each of the first and second discrete narrow-band light sources 212 and 214 may be an LED with a bandpass filter.

[0041] FIG. 4 illustrates the root-mean- square error of a daylight mimic for a mouse as a function of two peak wavelengths used as the daylight mimic, according to some embodiments. The light source 210 may be configured to emit wavelengths selected based on data such as that shown in FIG. 4. The x-axis represents the first, shorter wavelength peak (in nm) and the y-axis represents the second, longer wavelength peak (in nm). The graph shows the error compared to a daylight standard for various combinations of the first and second peak wavelengths. As shown in this example, a first peak wavelength of 402.4 nm and a second peak wavelength of 510.8 nm may provide the lowest error relative to a daylight standard. However, as described elsewhere herein, the relative intensities of the wavelengths may also be adjusted to provide desired behavior with respect to a subject or kind of daylight. Moreover, it should be appreciated that the impact of the optical path to the subject may warrant an adjustment in wavelengths, as described herein.

[0042] System 200 further includes controller 220. In some embodiments, controller 220 may be configured to control the wavelengths and / or relative intensities of the wavelengths of light emitted from light source 210. In some embodiments, controller 220 may include suitable circuitry for setting the wavelengths and / or relative intensities of the wavelengths of light emitted from light source 210. For example, in one embodiment, light source 210 may emit light including a first peak wavelength and a second peak wavelength, where the first peak wavelength is shorter than the second peak wavelength. In this embodiment, controller 210 may be configured to adjust a relative intensity of the first peak wavelength and second peak wavelength such that an intensity of the first peak wavelength is between 0.5 and five fold the intensity of the second peak wavelength. This ratio of intensities may be even greater depending on the context, such as when colored cage materials are used for the subject. In some embodiments, the controller is configured to control a combined intensity of the first peak wavelength and the second peak wavelength to exceed a threshold level while maintaining a constant relative intensity ratio between the first peak wavelength and second peak wavelength. There may be situations where more than two wavelengths are desirable.

[0043] Controller 220 may be connected to light source 210 by means of connection 216. Connection 216 may be a wired connection or wireless and allows controller 220 to communicate with light source 210 for the purposes of controlling or setting the wavelengths and / or relative intensities of wavelengths of light emitted. In various embodiments, controller 220 may be a microcontroller, computer, or other control system. In some embodiments, controller 220 may be configured to perform its operations automatically. In various embodiments, connection 216 may be a wired connection, or any other suitable connection for controlling emission of light from light source 210.

[0044] System 200 further includes sensor 240. In various embodiments, sensor 240 may either be a light sensor (e.g., a photodetector) or another type of environmental sensor configured to sense a condition of light. In some embodiments, sensor 240 may detect one or more characteristics of the light emitted by light source 210.

[0045] In some embodiments, sensor 240 may be configured to sense the intensities of light across multiple wavelengths. In some embodiments, sensor 240 may be configured to sense the intensities of light across wavelengths from ultraviolet to near infrared. In some embodiments, sensor 240 may be configured to sense the approximate spectrum and intensity of light. In some embodiments, sensor 240 may be configured to sense the intensities of light at particular wavelengths corresponding to the relevant wavelengths for mimicking natural light for specific species.

[0046] In some embodiments, sensor 240 may be a spectrometer. In some embodiments, sensor 240 may be a lux meter. In some embodiments, sensor 240 may be any suitable light meter configured to measure or approximate the spectrum and intensity of the emitted light.

[0047] Sensor 240 may be connected to controller 220 by connection 218. Information about the one or more characteristics of the light detected by sensor 240 may be communicated to controller 220 via connection 218. In various embodiments, connection 218 may be a wired connection, or any other suitable connection for communicatively coupling sensor 240 and controller 220.

[0048] In response to the information about the one or more characteristics detected by sensor 240 and received via connection 218, controller 220 may adjust the wavelengths and / or relative intensities of the wavelengths of the light emitted by light source 210. In some embodiments, sensor 240 may be configured to perform its operations automatically.

[0049] In system 200, light emitted by light source 210 is incident upon the cornea of a subject 230, located behind cage 232. In some embodiments, subject 230 may be an organism being used in an experiment, such as a rat, rabbit, cat, or dog. In an example embodiment of system 200, subject 230 is a mouse. Controller 220 may adjust the wavelengths and / or relative intensities of the wavelengths of the light emitted by light source 210 in response to the one or more characteristics detected by sensor 240, as described above, so that the light emitted from light source 210 mimics the engagement by daylight of the visual pigments of subject 230. For example, in the example embodiment in which subject 230 is a mouse, controller 220 may adjust the wavelengths and / or relative intensities of the wavelengths of the light emitted by light source 210 so that the light emitted by light source 210 engages the rhodopsin in rods, UWS and MWS pigments in cones, and melanopsin (MelE, MelM, and MelR) in ipRGCs of a mouse in the same way that daylight would. In this case, controller 220 may control the wavelengths emitted by light source 210 such that light source 210 emits light of wavelengths corresponding to those described above in connection with peak wavelengths 101 and 102 (e.g., 402.4 nm and 510.8 nm, the theoretical ideals, or 405 nm and 531 nm). In this case, controller 220 may further control the intensities of the light emitted by light source 210 such that light source 210 emits the light of shorter wavelength at a greater intensity than the light of the longer wavelength. For instance, if the wavelengths are 402.4 nm and 510.8 nm, the controller 220 may set the intensity of the shorter wavelength at approximately 0.93 times greater than that of the longer wavelength. If the wavelengths differ, the ratios may differ accordingly. For example, for 405 nm and 531 nm, the controller 220 may set the intensity of the shorter wavelength at 54.8 times greater than the longer wavelength.

[0050] In some embodiments, controller 220 may adjust the wavelengths and / or relative intensities of the wavelengths of the light emitted by light source 210 so that the light emitted by light source 210 mimics daylight for a rat. In this case, controller 220 may control the wavelengths emitted from light source 210 such that light source 210 emits light of wavelengths of 403 nm and 510 nm. In this case, controller 220 may further control the intensities of the light emitted from light source 210 such that light source 210 emits the light of shorter wavelength at an intensity of 0.99 times the light of longer wavelength.

[0051] In some embodiments, controller 220 may adjust the wavelengths and / or relative intensities of the wavelengths of the light emitted by light source 210 so that the light emitted by light source 210 mimics daylight for a rabbit. In this case, controller 220 may control the wavelengths emitted from light source 210 such that light source 210 emits light of wavelengths of approximately 448 nm (e.g., the theoretical ideal is 448. 2 nm) and approximately 525 nm (e.g., the theoretical ideal is 522.5 nm). In this case, controller 220 may further control the intensities of the light emitted from light source 210 such that light source 210 emits the light of shorter wavelength at an intensity of between 1 and 5 (e.g., 0.76 or 0.9) times as great as the light of longer wavelength.

[0052] In some embodiments, controller 220 may adjust the wavelengths and / or relative intensities of the wavelengths of the light emitted by light source 210 so that the light emitted by light source 210 mimics daylight for a cat. In this case, controller 220 may control the wavelengths emitted from light source 210 such that light source 210 emits light of wavelengths between 467 nm and 469 nm, for example at 468 nm and between 552 nm and 555 nm, for example at 553.6 nm. In this case, controller 220 may further control the intensities of the light emitted from light source 210 such that light source 210 emits the light of shorter wavelength at an intensity of between 0.1 and 1 (e.g., 0.36) times the intensity of the light of longer wavelength.

[0053] In some embodiments, controller 220 may adjust the wavelengths and / or relative intensities of the wavelengths of the light emitted by light source 210 so that the light emitted by light source 210 mimics daylight for a dog. In this case, controller 220 may control the wavelengths emitted from light source 210 such that light source 210 emits light of wavelengths between 454 nm and 457 nm, for example at approximately 455.7 nm and between 545 nm and 548 nm, for example at approximately 546.2 nm. In this case, controller 220 may further control the intensities of the light emitted from light source 210 such that light source 210 emits the light of shorter wavelength at an intensity between 0.1 and 5 (e.g., 3.3) times the intensity of the light of longer wavelength.

[0054] In some embodiments, controller 220 may adjust the wavelengths and / or relative intensities of the wavelengths of the light emitted by light source 210 so that the light emitted by light source 210 mimics daylight for a human not within a cage but behind a partition. In this case, controller 220 may control the wavelengths emitted from light source 210 such that light source 210 emits light of wavelengths of approximately 461 nm (e.g., 461.3 nm) and 548 nm (e.g., 547.4 nm). In this case, controller 220 may further control the intensities of the shorter wavelength of light emitted from light source 210 to have an intensity between 0.5 and 5 (e.g., 2.5) times that of the longer wavelength of light.

[0055] In some embodiments, controller 220 may be configured to adjust the wavelengths and relative intensities of the light emitted by light source 210 based on the actual light sources and optical filters used, and on any new knowledge of biological optics and / or visual pigments. In some embodiments, controller 220 may be configured to adjust the relative intensities of the light emitted by light source 210 to correct for the optical path that the light takes to reach the retinal photoreceptors of subject 230.

[0056] In the example embodiment in which subject 230 is a mouse, controller 220 may control light source 210 to emit light of those wavelengths described above for a daylight mimic for a mouse. Controller 220 may then adjust the relative intensities of the two wavelengths of light such that the light of shorter wavelength is provided at an intensity between 0.5 times and 54 times greater than that at which the light of longer wavelength is provided. For example, controller 220 may control light source 210 to emit light of wavelengths between 395 nm and 405 nm, for example at 402.4 nm and between 495 nm and 535 nm, for example at 510.8 nm, as described above. Controller 220 may then adjust the relative intensities of the two wavelengths of light such that the shorter wavelength is emitted at an intensity 1.5 times greater than that at which the longer wavelength is emitted. This adjustment by controller 220 corrects for the optical path of the light through the optics of the eye of the mouse, which preferentially absorb short wavelengths.

[0057] Similarly, in the embodiment in which subject 230 is a rat, controller 220 may control light source 210 to emit light of those wavelengths described above for a daylight mimic configured for a rat. Controller 220 may then adjust the relative intensities of the two wavelengths of light such that the light of shorter wavelength is emitted at an intensity between 0.5 and 5 times greater than that at which the light of longer wavelength is emitted, in order to correct for the optics of the eye of the rat. For example, if the subject 230 is a rat, controller 220 may control light source 210 to emit light of wavelengths between 402 nm and 406 nm, for example at 403.5 nm and between 508 nm and 515 nm, for example at 509.9 nm. Controller 220 may then adjust the relative intensities of the two wavelengths of light such that the shorter wavelength light is emitted at an intensity 1.48 times greater than the longer wavelength. This control may correct for the optics of the eye of the rat.

[0058] Similarly, in the embodiment in which subject 230 is a rabbit, controller 220 may control light source 210 to emit light of those wavelengths described above for a daylight mimic configured for a rabbit. Controller 220 may then adjust the relative intensities of the two wavelengths of light such that the light of shorter wavelength is emitted at an intensity between 0.1 and 5 (e.g., 0.85) times greater than that at which the light of longer wavelength is emitted, to correct for the optics of the eye of the rabbit. For example, controller 220 may control light source 210 to emit light of wavelengths between 447 nm and 449 nm, for example at 448.2 nm and between 521 nm and 525 nm, for example at 522.5 nm. Controller 220 may then adjust the relative intensities of the two wavelengths of light such that the light of shorter wavelength is emitted at an intensity 0.85 times that at which the longer wavelength is emitted, to correct for the optics of the eye of the rabbit.

[0059] Similarly, in the embodiment in which subject 230 is a cat, controller 220 may control light source 210 to emit light of those wavelengths described above for daylight mimics configured for a cat. Controller 220 may adjust the relative intensities of the two wavelengths of light such that the light of shorter wavelength is emitted at an intensity of 0.84 times that at which the light of longer wavelength is emitted, to correct for the optics of the eye of the cat.

[0060] Similarly, in the embodiment in which subject 230 is a dog, controller 220 may control light source 210 to emit light of those wavelengths described above for daylight mimics configured for a dog. Controller 220 may adjust the relative intensities of the two wavelengths of light such that the light of shorter wavelength is emitted at an intensity 0.77 times that at which the light of longer wavelength is emitted, to correct for the optics of the eye of the dog.

[0061] Similarly, in the embodiment in which subject 230 is a human, controller 220 may control light source 210 to emit light of those wavelengths described above for daylight mimics configured for humans. Controller 220 may then adjust the relative intensities of the two wavelengths of light such that the light of shorter wavelength is emitted at an intensity 0.77 times that at which the light of longer wavelength is emitted, to correct for the optics of the eye of the human. In some embodiments, controller 220 may adjust the relative intensities of the light emitted by light source 210 to correct for an optical path of the light through a cage 232 before reaching the retinal photoreceptors of subject 230. In an example embodiment in which light source 210 emits light including a first peak wavelength and a second peak wavelength, where the first peak wavelength is shorter than the second peak wavelength, controller 220 may be configured to adjust a relative intensity of the first peak wavelength and second peak wavelength to account for passage of the light through cage 232 such that an intensity of the first peak wavelength is a fraction of (e.g., 0.93 times) the intensity of the longer peak wavelength. For example, in an embodiment in which subject 230 is a mouse and the optical path of the light emitted by light source 210 causes the light to pass through a conventional amber cage 232 before reaching the retinal photoreceptors of the mouse, controller 220 may adjust the relative intensities of the light emitted by light source 210 such that light of wavelength between 395 nm and 405 nm, for example at around 402.4 nm or 405 nm is emitted at an intensity -0.93 times that at which light of wavelength between 495 nm and 535 nm (e.g., 510.8 nm or 531 nm) is emitted.

[0062] In some embodiments, controller 220 may be configured to adjust the overall intensity of the light emitted by light source 210, while keeping the relative intensities of the wavelengths fixed. In some embodiments, controller 220 may be configured to control an overall intensity of the light to exceed a threshold level while maintaining a constant relative intensity ratio of the peak wavelengths. For example, controller 220 may be configured to increase or decrease the overall intensity of the light emitted by light source 210 to match or exceed the intensity levels of the light in the surrounding environment, as needed.

[0063] It is to be understood that the disclosed subject matter is not limited in its application to the examples set forth in the foregoing description. Controller 220 may be configured to adjust the wavelengths and / or relative intensities of the wavelengths of the light emitted by light source 210 to mimic any desired spectrum of natural light, including daylight. Additionally, or alternatively, controller 220 may be configured to adjust the wavelengths and / or relative intensities of the wavelengths of the light emitted by light source 210 to accommodate different light paths, light spectra, and species. In the case of species that have more complex complements of visual pigments, controller 220 may be configured to use the minimum number of wavelengths above two that is necessary to mimic natural light for that species.

[0064] The light source 210 may be implemented as a standalone device or as a component of another device. For example, in some embodiments light source 210 may form part of a microscope or be configured to supply its light to a microscope. The ratio of the intensity of the peak wavelengths may be adjusted to counterbalance differential attenuation resulting from the microscope’s optics.

[0065] FIG. 3 illustrates a method 300 of illuminating a set of visual pigments in a mouse with an artificial light source to mimic daylight, according to some embodiments. In step 310, a controller adjusts the output light from a light source to output light with wavelengths and relative intensities of wavelengths that will mimic daylight. Specifically, for mimicking daylight for a mouse, the controller adjusts the output light to consist of light of peak wavelengths of between 395 nm and 405 nm, for example at 402.4 nm (the theoretical ideal) or 405 nm, and between 495 nm and 535 nm, for example at 510.8 nm (the theoretical ideal) or 531 nm, wherein the intensity of the light of shorter wavelength is between 0.5 to five fold that of the light of longer wavelength. As a non-limiting example of step 310, a controller may control the output of light consisting of two peak wavelengths at 402.4 nm and 510.8 nm with the light at 402.4 nm being between 0.5 and 5 times as great as the light at 510.8 nm.

[0066] In step 320, a sensor senses one or more characteristics of the light that was emitted by the light source in step 310. Alternatively, or additionally, in some embodiments, in step 320, the sensor may sense a condition of the surrounding environment. The responses of such a sensor would provide relevant information about the spectrum and intensity of illumination.

[0067] In some embodiments, the sensor may be configured to sense the intensities of light across multiple wavelengths. In some embodiments, the sensor may be configured to sense the intensities of light across wavelengths from ultraviolet to near infrared. In some embodiments, the sensor may be configured to sense the approximate spectrum and intensity of light. In some embodiments, the sensor may be configured to sense the intensities of light at particular wavelengths corresponding to the relevant wavelengths for mimicking natural light for specific species.

[0068] In some embodiments, the sensor may be a spectrometer. In some embodiments, the sensor may be a lux meter. In some embodiments, the sensor may be any suitable light meter configured to measure or approximate the spectrum and intensity of the emitted light.

[0069] In step 330, the controller adjusts the wavelengths and / or relative intensities of the wavelengths of the light emitted by the light source in response to the information sensed by the sensor in step 320. In particular, the controller will respond to the sensed information by adjusting the light emitted by the light source such that the light emitted by the light source mimics daylight for a mouse. In some embodiments, this may consist of adjusting the emitted light to account for the optical path in front of the visual pigments of the mouse, which may include passage of the light through materials involved in an experimental set-up and / or through ocular tissues.

[0070] Daylight mimics according to aspects of the present application may provide various benefits, some of which have been described and some of which are now listed. It should be appreciated that not every embodiment necessarily provides every benefit, and that benefits other than those now listed may be provided by at least some embodiments. In some embodiments, a simple daylight mimic is provided with easy control of the relative ratios of intensity of different peak wavelengths. The simple design and control of the daylight mimic may permit widespread application and integration into larger devices, such as microscopes and light therapy sources. The use of a light sensor and control loop may permit adaptation of the daylight mimic to the specific optical paths present in a given housing, lab, or experimental setting. The daylight mimic may facilitate creation of a natural environment for a test subject or patient, thereby increasing the chance of accurate test results and light therapy. The daylight mimic may facilitate the creation of architectural or environmental lighting that mimics natural light for the general population.

[0071] It should be appreciated that the specific value of peak wavelengths of a daylight mimic may differ slightly from those numbers listed herein. The term “approximately” in the context of identifying a peak wavelength may encompass + / - 2% of the identified peak wavelength in some embodiments and in some embodiments + / - 5% of the identified peak wavelength. For example, a peak wavelength of approximately 405 nm may include values from 397 nm to 413 nm, depending on the specifications of the particular light source, optical filters, optical paths, and photochemical properties of the visual pigments in question. .

[0072] Daylight mimics having a small number of peak wavelengths have been described here. In some embodiments, a daylight mimic produces light consisting of two peak wavelengths. In some embodiments, the daylight mimic produces light consisting of three peak wavelengths. A small number of peak wavelengths is beneficial to mimic daylight while allowing simple and accurate control over the wavelengths and their intensity in diverse contexts.

[0073] It is to be noted that the term “daylight” in the foregoing description denotes the International Commission on Illumination (CIE) daylight illuminant D65 standard. The wavelengths and their ratios may be altered to match other natural light spectra.

[0074] It is to be understood that the disclosed subject matter is not limited in its application to the details of construction and to the arrangements of the components set forth in the foregoing description or illustrated in the drawings. The disclosed subject matter is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.

[0075] As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods, and systems for carrying out the several purposes of the disclosed subject matter. It is important, therefore, that the description provided herein be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the disclosed subject matter.

[0076] Also, the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” “having,” “containing,” “involving,” and variations thereof herein, is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The term “consisting of’ is closed- ended.

[0077] Although the disclosed subject matter has been described and illustrated in the foregoing non-limiting embodiments, it is understood that the present disclosure has been made only by way of example, and that numerous changes in the details of implementation of the disclosed subject matter may be made without departing from the spirit and scope of the disclosed subject matter.

Claims

CLAIMSWhat is claimed is:

1. An apparatus, comprising: an artificial illumination light source configured to mimic how natural light engages an organism’s visual pigments by producing an output spectrum having no more than three peak wavelengths, the artificial illumination light source comprising: a first discrete narrow-band light source emitting light at a first peak wavelength; a second discrete narrow-band light source emitting light at a second peak wavelength.

2. The apparatus of claim 1, wherein: the organism is a mouse; the first peak wavelength is approximately between approximately 395 nanometers and approximately 405 nanometers; and the second peak wavelength is approximately between approximately 495 nanometers and approximately 535 nanometers.

3. The apparatus of claim 1, wherein the first discrete narrow-band light source and the second discrete narrow-band light source each comprise a source with a bandpass filter.

4. The apparatus of claim 1, further comprising a controller configured to control characteristics of the output spectrum by controlling the first discrete narrow-band light source and the second discrete narrow-band light source.

5. The apparatus of claim 4, further comprising a sensor configured to detect characteristics of the light emitted by the first discrete narrow-band light source and the second discrete narrow-band light source, and further configured to communicate information about the characteristics of the light emitted by the first discrete narrow-band light source and the second discrete narrow-band light source to the controller.

6. The apparatus of claim 5, wherein the controller and the sensor are configured in a control loop such that the controller automatically adjusts operation of the first discrete narrow-band light source and / or second discrete narrow-band light source based on input from the sensor.

7. The apparatus of claim 4, wherein the controller is configured to adjust a relative intensity of the first peak wavelength and second peak wavelength such that an intensity of the first peak wavelength is between 0.5 and five fold the intensity of the second peak wavelength, and wherein the first peak wavelength is shorter than the second peak wavelength.

8. The apparatus of claim 4, wherein the controller is configured to adjust a relative intensity of the first peak wavelength and second peak wavelength to account for passage of the light through a cage, such that an intensity of the first peak wavelength is between 0.8 and 0.95 times an intensity of the second peak wavelength, and wherein the first peak wavelength is shorter than the second peak wavelength.

9. The apparatus of claim 4, wherein the controller is configured to control a combined intensity of the first peak wavelength and the second peak wavelength to exceed a threshold level while maintaining a constant relative intensity ratio between the first peak wavelength and second peak wavelength.

10. The apparatus of claim 4, wherein: the organism is a rat; the first peak wavelength is approximately between 402 nanometers and 406 nanometers; the second peak wavelength is approximately between 508 nanometers and 515 nanometers; and the controller is configured to set a first intensity of the first peak wavelength and a second intensity of the second peak wavelength such that the first intensity at a retina of the rat is 1.15 times greater than the second intensity at the retina of the rat.

11. The apparatus of claim 1, wherein: the organism is a rabbit; the first peak wavelength is approximately between 447 nanometers and 449 nanometers; the second peak wavelength is approximately between 521 nanometers and 525 nanometers; and the controller is configured to set a first intensity of the first peak wavelength and a second intensity of the second peak wavelength such that the first intensity at a retina of the rabbit is 0.76 times the second intensity at the retina of the rabbit.

12. The apparatus of claim 1, wherein: the organism is a human; the first peak wavelength is approximately between 460 nanometers and 468 nanometers; the second peak wavelength is approximately between 546 nanometers and 564 nanometers; and the controller is configured to set a first intensity of the first peak wavelength and a second intensity of the second peak wavelength such that the first intensity at a retina of the human is 0.62 times the second intensity at the retina of the human.

13. A method of illuminating a set of visual pigments with an artificial light source, comprising: controlling emission of light from a light source to emit light toward an organism such that the light exhibits a spectrum having no more than three peak wavelengths.

14. The method of claim 13, further comprising: adjusting an intensity ratio between the no more than three peak wavelengths to compensate for a path traversed by the light prior to reaching the visual pigments.

15. The method of claim 14, further comprising adjusting the intensity ratio to mimic a particular spectrum of daylight.

16. The method of claim 14, wherein the path comprises optics of an eye of the organism.

17. The method of claim 14, wherein the path comprises material of a cage in which the organism is located.

18. The method of claim 13, wherein the no more than three peak wavelengths comprises a first peak wavelength of between 380 nanometers and 700 nanometers and a second peak wavelength of between 380 nanometers and 700 nanometers.

19. The method of claim 13, further comprising sensing the light emitted with a sensor and adjusting emission of the light from the light source in response to input from the sensor.

20. The method of claim 19, wherein adjusting the emission comprises automatically adjusting the emission based on the input from the sensor.

21. The method of claim 20, wherein adjusting the emission comprises adjusting a relative intensity of peak wavelengths in the emission.

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