Wearable device to prevent or stop myopia

Abstract

A body-wearable light exposure monitoring device uses device orientation sensing to correct device-sensed light levels. The device may be worn on the wrist or at another body part, and its measurements used to estimate a light exposure level experienced by the eyes (retina) of the wearer. In some embodiments, a light exposure calculator of the device accesses light measurements from one or more light-measuring sensors, and orientation measurements from a device orientation sensor. The light measurements are adjusted, using the orientation measurements, to calculate an estimated level of physiologically active exposure to light, for example exposure to light sufficient to provide prophylaxis against the condition of myopia, or another condition. In some embodiments, monitoring of potentially deleterious exposure to light such as UV light is also performed.

Description

[0001] WEARABLE DEVICE TO PREVENT OR STOP MYOPIA

[0002] RELATED APPLICATIONS

[0003] This application claims the benefit of priority of U.S. Provisional Patent Application No. 63 / 569,834 filed on 26 March 2024, the contents of which are incorporated herein by reference in their entirety.

[0004] FIELD AND BACKGROUND OF THE INVENTION

[0005] The present invention, in some embodiments thereof, relates to the field of light exposure measurement, and more particularly, but not exclusively, to monitoring of light exposure levels with potential biological activity.

[0006] Light exposure has potentially both advantageous and deleterious effects, according to exposure amount and wavelength. Deleterious effects include effects due to excessive exposure to solar UV radiation, including sunburn and skin cancer. Conditions for which light exposure has been implicated as a potentially protective factor include vitamin D deficiency, certain skin conditions, certain mood / sleep disorders, and some eye conditions, including diabetic retinopathy, diabetic macular oedema, and the extremely common condition of myopia, often acquired in childhood and also later in adulthood.

[0007] SUMMARY OF THE INVENTION

[0008] Following is a non-exclusive list including some examples of embodiments of the invention. The invention also includes embodiments which include fewer than all the features in an example and embodiments using features from multiple examples, also if not expressly listed below.

[0009] Example 1. A body-wearable light exposure monitoring device (100), comprising: a housing (101) including: a light- measuring sensor (103), a device orientation sensor (104), housed to move with the light-measuring sensor (103) while measuring an orientation of the light-measuring sensor (103), a light exposure indicator (102), and a light exposure calculator (75); wherein the light exposure calculator (75): accesses light measurements (62) from the light- measuring sensor (103) and orientation measurements (68) from the device orientation sensor (104), and uses the light measurements (62) to calculate an estimated level of physiologically active exposure to light (80), and provides the estimated level of physiologically active exposure to light to the light exposure indicator (102); wherein the light exposure calculator (75) uses the orientation measurements to determine adjustments (63) used to calculate the estimated level of physiologically active exposure to light (80).

[0010] Example 2. The device (100) of example 1, wherein the light exposure calculator (75) calculates the estimated level of physiologically active exposure to light (80) for a first body part

[0011] (3), using the orientation measurements (68) as indications of the orientation of a second body part

[0012] (4).

[0013] Example 3. The device (100) of example 2, wherein the first body organ (3) comprises a retina (3A), and the second body organ (4) comprises a limb.

[0014] Example 4. The device (100) of example 2, wherein the first body organ (3) comprises a retina (3A), and the second body organ (4) comprises a head or torso.

[0015] Example 5. The device (100) of example 2, wherein the first body organ comprises exposed skin surface, and the second body organ comprises a limb, head, or torso.

[0016] Example 6. The device (100) of any one of examples 1-4, wherein the light exposure indicator (102) relates the estimated level of physiologically active exposure to light (80) to a daily period of exposure to light estimated to provide adequate protection from an adverse physiological condition.

[0017] Example 7. The device (100) of example 6, wherein the adverse physiological condition comprises myopia.

[0018] Example 8. The device (100) of any one of examples 6-7, wherein the adverse physiological condition comprises an affective disorder.

[0019] Example 9. The device (100) of any one of examples 6-8, wherein the adverse physiological condition comprises a vitamin deficiency.

[0020] Example 10. The device (100) of any one of examples 6-9, wherein the light exposure calculator (75) estimates a contribution of light to provide adequate protection from the adverse physiological condition according to brightness.

[0021] Example 11. The device (100) of example 10, wherein the calculator uses a brightness threshold to estimate the contribution of light to provide adequate protection from the adverse physiological condition. Example 12. The device (100) of any one of examples 10-11, wherein the brightness threshold corresponds to exposure to outdoors daylight.

[0022] Example 13. The device (100) of example 10, wherein the calculator estimates the contribution of light to provide adequate protection from the adverse physiological condition according to a weighted function including two or more brightnesses contributing non-zero contributions to the weighted function.

[0023] Example 14. The device (100) of any one of examples 6-13, wherein the light exposure calculator (75) estimates the contribution of light to provide adequate protection from the adverse physiological condition according to duration of exposure to light.

[0024] Example 15. The device (100) of any one of examples 6-14, wherein the light exposure calculator (75) estimates a contribution of light to provide adequate protection from the adverse physiological condition according to light wavelength.

[0025] Example 16. The device (100) of example 15, wherein the light-measuring sensor (103) selectively measures a range of wavelengths estimated to confer protection from the adverse physiological condition.

[0026] Example 17. The device (100) of example 15, wherein the light-measuring sensor (103) measures a range of wavelengths not selective for wavelengths estimated to confer protection from the adverse physiological condition, and the light exposure calculator (75) estimates exposure to a range of wavelengths estimated to confer protection from the adverse physiological condition using the wavelength non-selective measurements.

[0027] Example 18. The device (100) of any one of examples 1-17, wherein the light exposure calculator (75) estimates a contribution of light to a potentially adverse physiological condition.

[0028] Example 19. The device (100) of example 18, wherein the adverse physiological condition comprises ultraviolet skin damage.

[0029] Example 20. The device (100) of any one of examples 18-19, wherein the adverse physiological condition comprises heat stroke.

[0030] Example 21. The device (100) of any one of examples 18-20, comprising a temperature sensor, wherein the light exposure calculator (75) uses the temperature sensor to determine adjustments to the estimated level of physiologically active exposure to light (80).

[0031] Example 22. The device (100) of any one of examples 18-19, wherein the light exposure calculator (75) estimates a contribution of light to the potential adverse physiological condition according to one or more of the group consisting of: light brightness, light wavelength, and length of light exposure. Example 23. The device (100) of any one of examples 18-22, when dependent on any one of examples 6-17, wherein a first range of estimated light exposure is estimated to contribute to the adverse physiological condition to which light exposure is estimated to contribute, a second range of estimated light exposure is estimated to contribute protection to the adverse physiological condition for which light exposure is estimated to provide protection, and the light exposure provides to the light exposure indicator (102) indications estimating at least relative amounts exposure for each of the first and second ranges of estimated light exposure.

[0032] Example 24. The device (100) of any one of examples 1-23, wherein the light exposure calculator (75) maintains a record of when light was measured at different orientations of the lightmeasuring sensor (103), determines when measurements made at an orientation are in need of updating, and prompts a wearer of the device (100) to change the orientation of the light-measuring sensor (103) accordingly.

[0033] Example 25. The device (100) of example 24, wherein the light exposure calculator (75) determines that measurements made at an orientation are in need of updating according to one or more of: whether light estimated to be productive of physiological activity has been measured at any orientation within a sufficiently recent time period; whether light brightness may potentially be at a current level estimated to be productive of physiological activity exists at the orientation, but measurements of light brightness at the orientation are not current.

[0034] Example 26. The device (100) of any one of examples 1-25, wherein the light exposure calculator (75) operates in a plurality of modes, the modes comprising at least: a daylight active mode, wherein the light exposure calculator (75) is biased to expect measurements of bright light; an inactive mode, wherein the light exposure calculator (75) is biased to expect measurements of dim light.

[0035] Example 27. The device (100) of example 26, wherein, in the daylight active mode, the light exposure calculator (75) assumes continuation of bright conditions for a longer period without direct measurement confirmation from the light-measuring sensor (103) than compared to the inactive mode.

[0036] Example 28. The device (100) of any one of examples 26-27, wherein, in the daylight active mode, the light exposure calculator (75) more actively prompts the wearer to adjust the orientation of the light measuring sensor to maintain confirmation of exposure to bright light than compared to the inactive mode.

[0037] Example 29. The device (100) of any one of examples 26-28, wherein the light exposure calculator (75) changes and / or maintains modes according to one or more of: how dynamically the orientation of the device (100) changes over time, an input from the user comprising manual operation of a control of the device (100), an input from the user comprising orienting the device (100) to provide an input signal to the light exposure calculator (75), and a temporal pattern of exposure to brighter and / or darker light.

[0038] Example 30. The device (100) of any one of examples 1-29, wherein the light exposure calculator (75): for each of a plurality of orientation ranges (69), determines, respectively: a sensed light level (6A) indicated by one or more of the light measurements (62), said one or more of the light measurements (62) being associated in time with one or more of the orientation measurements (68) corresponding to the orientation range; selects from among the sensed light levels (6 A) a maximum light level (6D); and uses the maximum light level (6D) to determine the adjustments (63) used to calculate the estimated level of physiologically active exposure to light (80).

[0039] Example 31. The device (100) of example 30, wherein the light exposure calculator (75) modifies the light levels (6A) according to indications by one or more additional light measurements (62A) and their respective additional orientation measurements (68A), and the maximum light level (6D) is re- selected accordingly.

[0040] Example 32. The device (100) of example 31, wherein the light exposure calculator (75) modifies the light levels (6A) by replacing them with the one or more additional light measurements (62A), according to their associated respective additional orientation measurements.

[0041] Example 33. The device (100) of example 31, wherein the light exposure calculator (75) modifies the light levels (6A) by weighted adjustment from the one or more additional light measurements (62A), according to their associated respective additional orientation measurements.

[0042] Example 34. The device (100) of example 33, wherein the weighted adjustment is weighted according to at least one of distance in time before and distance in time after the one or more additional light measurements (62A). Example 35. The device (100) of any one of examples 33-34, wherein the weighted adjustment is weighted according to at least one of angular azimuth distance and angular altitude distance from one or more of the plurality of orientation ranges of the respective additional orientation measurements.

[0043] Example 36. The device (100) of any one of examples 33-35, wherein the weighted adjustment is weighted to increase the influence of relatively higher light levels, compared to relatively lower light levels.

[0044] Example 37. The device (100) of any one of examples 30-36, wherein the plurality of orientation ranges comprise at least two angular altitude ranges distinguished by different angular altitudes.

[0045] Example 38. The device (100) of example 37, wherein the at least two angular altitude ranges comprise a first angular altitude range oriented most downward, a second angular altitude range oriented most upward, and a third angular altitude range in between the first and second ranges.

[0046] Example 39. The device (100) of any one of examples 37-38, wherein the at least two angular altitude ranges comprise at least eight angular altitude ranges arranged from most downward to most upward.

[0047] Example 40. The device (100) of any one of examples 30-39, wherein the plurality of orientation ranges comprise at least two azimuth ranges distinguished by different angular azimuths.

[0048] Example 41. The device (100) of example 40, wherein the at least two azimuth ranges comprise a first azimuth range oriented more toward a position of the sun, and a second range oriented less toward the position of the sun.

[0049] Example 42. The device (100) of any one of examples 40-41, wherein the at least two azimuth ranges comprise at least eight angular altitude ranges arranged from most downward to most upward.

[0050] Example 43. The device (100) of any one of examples 1-42, wherein the device orientation sensor (104) comprises one or more of the group consisting of: a gyroscope, an accelerometer, and a magnetic compass. Example 44. The device (100) of any one of examples 1-43, wherein the adjustments correspond to adjustments in an estimated brightness of the light indicated by the light measurements (62).

[0051] Example 45. A method of providing an estimated level of physiologically active exposure to light, the method comprising: accessing, by a light exposure calculator (75) comprising a processor (400): light measurements (62) made by a light-measuring sensor (103), and orientation measurements (68) made by a device orientation sensor (104), positioned to measure an orientation (67) of the light-measuring sensor (103); calculating, by the processor and using the light measurements (62), the estimated level of physiologically active exposure to light, the calculating comprising using the orientation measurements to determine adjustments (63) to the estimated level.

[0052] Unless otherwise defined, all technical and / or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure pertains. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present disclosure, exemplary methods and / or materials are described below. In case of conflict, the patent specification, including definitions, controls. In addition, the materials, methods, and examples are illustrative only and are not intended to be necessarily limiting.

[0053] As will be appreciated by one skilled in the art, aspects of the present disclosure may be embodied as a system, method, or computer program product. Accordingly, aspects of the present disclosure may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, microcode, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module” or “system” (e.g., a method may be implemented using “computer circuitry”). Furthermore, some embodiments of the present disclosure may take the form of a computer program product embodied in one or more computer readable medium(s) having computer readable program code embodied thereon. Implementation of the method and / or system of some embodiments of the present disclosure can involve performing and / or completing selected tasks manually, automatically, or a combination thereof. Moreover, according to actual instrumentation and equipment of some embodiments of the method and / or system of the present disclosure, several selected tasks could be implemented by hardware, by software or by firmware and / or by a combination thereof, e.g., using an operating system. For example, hardware for performing selected tasks according to some embodiments of the present disclosure could be implemented as a chip or a circuit. As software, selected tasks according to some embodiments of the present disclosure could be implemented as a plurality of software instructions being executed by a computer using any suitable operating system. In some embodiments of the present disclosure, one or more tasks performed in method and / or by system are performed by a data processor (also referred to herein as a “digital processor”, in reference to data processors which operate using groups of digital bits), such as a computing platform for executing a plurality of instructions. Instruction executing elements of the processor may comprise, for example, one or more microprocessor chips, ASICs, and / or FPGAs. Optionally, the data processor includes a volatile memory for storing instructions and / or data and / or a non-volatile storage, for example, a magnetic hard-disk and / or removable media, for storing instructions and / or data. Optionally, a network connection is provided as well. A display and / or a user input device such as a keyboard or mouse are optionally provided as well. Any of these implementations are referred to herein more generally as instances of computer circuitry.

[0054] Any combination of one or more computer readable medium(s) may be utilized for some embodiments of the present disclosure. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device. A computer readable storage medium may also contain or store information for use by such a program, for example, data structured in the way it is recorded by the computer readable storage medium so that a computer program can access it as, for example, one or more tables, lists, arrays, data trees, and / or another data structure. Herein a computer readable storage medium which records data in a form retrievable as groups of digital bits is also referred to as a digital memory. It should be understood that a computer readable storage medium, in some embodiments, is optionally also used as a computer writable storage medium, in the case of a computer readable storage medium which is not read-only in nature, and / or in a read-only state.

[0055] Herein, a data processor is said to be “configured” to perform data processing actions insofar as it is coupled to a computer readable medium to receive instructions and / or data therefrom, process them, and / or store processing results in the same or another computer readable medium. The processing performed (optionally on the data) is specified by the instructions, with the effect that the processor operates according to the instructions. The act of processing may be referred to additionally or alternatively by one or more other terms; for example: comparing, estimating, determining, calculating, identifying, associating, storing, analyzing, selecting, and / or transforming. For example, in some embodiments, a digital processor receives instructions and data from a digital memory, processes the data according to the instructions, and / or stores processing results in the digital memory. In some embodiments, “providing” processing results comprises one or more of transmitting, storing and / or presenting processing results. Presenting optionally comprises showing on a display, indicating by sound, printing on a printout, or otherwise giving results in a form accessible to human sensory capabilities.

[0056] A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electromagnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.

[0057] Program code embodied on a computer readable medium and / or data used thereby may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

[0058] Computer program code for carrying out operations for some embodiments of the present disclosure may be written in any combination of one or more programming languages, including an object-oriented programming language such as Java, Smalltalk, C++ or the like and conventional procedural programming languages, such as the “C” programming language or similar programming languages. Additionally or alternatively, sequences of logical operations (optionally logical operations corresponding to computer instructions) may be embedded in the design of an ASIC and / or in the configuration of an FPGA device. The program code may execute entirely on the user’s computer, partly on the user’s computer (e.g., as a stand-alone software package), partly on the user’s computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user’s computer through any type of network, including a local area network (LAN) or other wireless protocols (e.g., peer to peer in general, Bluetooth, ZigBee, UWB) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).

[0059] Some embodiments of the present disclosure may be described below with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the present disclosure. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks.

[0060] These computer program instructions may also be stored in a computer readable medium that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the computer readable medium produce an article of manufacture including instructions which implement the function / act specified in the flowchart and / or block diagram block or blocks.

[0061] The computer program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks.

[0062] Some of the methods described herein are generally designed only for use by a computer; and may not be feasible or practical for performing purely manually, by a human expert. A human expert who wanted to manually perform similar tasks, such inspecting objects, might be expected to use completely different methods, e.g., making use of expert knowledge and / or the pattern recognition capabilities of the human brain, which would be vastly more efficient than manually going through the steps of the methods described herein. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0063] Some embodiments of the present disclosure are herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example, and for purposes of illustrative discussion of embodiments of the present disclosure. In this regard, the description taken with the drawings makes apparent to those skilled in the art how embodiments of the present disclosure may be practiced.

[0064] In the drawings:

[0065] Figs. 1A-1D schematically illustrate a wrist-wearable light exposure measurement device, according to some embodiments of the present disclosure;

[0066] Fig. IE illustrates a ring-based light exposure measurement devices, in accordance with some embodiments of the present disclosure;

[0067] Figs. 2A-2B schematically illustrate wearing of a wrist-wearable light exposure measurement device, according to some embodiments of the present disclosure;

[0068] Fig. 2C schematically illustrates light impinging separately on a body organ of interest (e.g., a retina), and on light exposure measurement device itself, according to some embodiments of the present disclosure;

[0069] Fig. 3A is a schematic graph illustrating, for a single selected orientation, sensed- orientation based light exposure calibration of a wrist-wearable light exposure measurement device, according to some embodiments of the present disclosure;

[0070] Fig. 3B is a schematic graph illustrating, for a full range of elevation angles, sensed- orientation based light exposure calibration of a wrist-wearable light exposure measurement device, according to some embodiments of the present disclosure;

[0071] Fig. 3C is a schematic graph illustrating, for a full range of azimuth angles, sensed- orientation based light exposure calibration of a wrist-wearable light exposure measurement device, according to some embodiments of the present disclosure;

[0072] Fig. 4A is a schematic block diagram illustrating functional-level components of a light exposure measurement device, according to some embodiments of the present disclosure;

[0073] Fig. 4B is a schematic block diagram illustrating components and data structures for a light exposure calculator of a light exposure measurement device, according to some embodiments of the present disclosure;

[0074] Fig. 4C is a schematic flow chart illustrating operation of a light exposure measurement device, according to some embodiments of the present disclosure; Fig. 4D is a schematic flow chart illustrating operation of a light exposure measurement device, including certain options for internal operations, according to some embodiments of the present disclosure;

[0075] Fig. 5A-5B schematically illustrate a light exposure indicator of a light exposure measurement device, according to some embodiments of the present disclosure;

[0076] Fig. 6 schematically illustrates a light exposure indicator of a light exposure measurement device, according to some embodiments of the present disclosure;

[0077] Fig. 7 schematically illustrates a light exposure indicator of a light exposure measurement device, according to some embodiments of the present disclosure;

[0078] Fig. 8 schematically illustrates a modular implementation of a watch band and a device housing, of a light exposure measurement device, according to some embodiments of the present disclosure;

[0079] Fig. 9A schematically illustrates an assembled state of the watch band and the device housing, according to some embodiments of the present disclosure;

[0080] Fig. 9B schematically illustrates an exploded view of the device housing, according to some embodiments of the present disclosure;

[0081] Fig. 10A schematically illustrates a charging device for a light exposure measurement device, according to some embodiments of the present disclosure;

[0082] Fig. 10B schematically illustrates a remote application for a light exposure measurement device, according to some embodiments of the present disclosure;

[0083] Fig. 11A schematically illustrates fashion-band implementations of a light exposure measurement device, according to some embodiments of the present disclosure;

[0084] Figs. 11B-11G schematically illustrate alternative implementation styles for a housing and wrist band of a light exposure measurement device, according to some embodiments of the present disclosure;

[0085] Figs. 12A-12C schematically illustrate a clothing clip that receives, by insertion, a housing of a light exposure measurement device, according to some embodiments of the present disclosure; and

[0086] Figs. 13A-13C schematically illustrate a clothing clip which receives by insertion a housing of a light exposure measurement device, and is also usable with a wrist band, according to some embodiments of the present disclosure. DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

[0087] The present invention, in some embodiments thereof, relates to the field of light exposure measurement, and more particularly, but not exclusively, to monitoring of light exposure levels with potential biological activity.

[0088] Overview

[0089] An aspect of some embodiments of the present disclosure relates to body-worn lightsensing devices, calibrated to provide an indication of effective levels of exposure to daylight. In some embodiments, the light-sensing device is configured to indicate ocular exposure to daylight levels deemed sufficient to stimulate regular ocular development. In some embodiments, the lightsensing device is configured to indicate a cumulative daily exposure to such daylight levels.

[0090] In some embodiments, the light-sensing device is configured (additionally or alternatively) to indicated exposure of another part of the body (for example, exposed skin, and / or the body of the wearer generally) and / or relative to another exposure standard for light. For example, but not limited to, the standard may be for light which is harmful (e.g., UV radiation), and / or for light which is beneficial in another way, e.g., considered to promote levels of a substance within the body such as vitamin D, considered to be antimicrobial, considered to be a treatment for a skin condition such as dermatitis and / or psoriasis, and / or considered to be related to mood and / or impact on hormone production such as dominion and melatonin.

[0091] Light Levels and Myopia

[0092] As an indication of potential utility, and without committing to or relying exclusively on a particular theory of operation, some research has suggested that blue light wavelength exposure plays a role (as an environmental factor) in regulating the growth of the eye. Relevant blue light wavelengths are optionally specified, for example, as wavelengths in the range of about 450 nm to 495 nm, or 420 nm to about 470 nm.

[0093] This is potentially via dopamine production triggered by blue light wavelength exposure. The dopamine may serve as part of developmental regulation to reach an ocular shape suitable to the optical accommodation of the cornea and lens. Accordingly, under this hypothesis: lacking a sufficient level of such photic stimulation, the developing eye is liable to become myopic. Independent of these specifics, a correlation between outdoor play and a lowered rate of myopia has been reported. In some embodiments, a target cumulative daily exposure comprises ocular exposure of (at least) 2.5 hours (150 minutes) duration to environmental illumination comprising or equivalent to daylight- spectrum light (outdoor sunlight) reaching or exceeding a threshold of 10,000 lux. In some embodiments, another range is selected, e.g., the threshold may be higher or lower (e.g., in the range of 5,000 lux to 15,000 lux), and the exposure time maybe higher or lower (e.g., in the range of 1 hour to 5 hours).

[0094] Optionally an integrated range is used; e.g., 25,000 lux-hours of exposure over the period of a day, optionally with a lower threshold below which exposure is not integrated, and / or optionally with an upper threshold above which and increased level of instantaneous exposure is not considered to be additive in the effect of concern. Optionally, integrated exposure-to-effect levels are determined from a table or function which is non-linear for some or all regimes of reasonably expected levels of light exposure. For example, ten minutes of exposure at an estimated 5,000 lux may be counted as equivalent to significantly less than five minutes of exposure at 10,000 lux (e.g., as equivalent to only about 2.5 minutes of such exposure), even though the integrated amounts of light as such are nominally the same. Such graded adjustments may be performed to take graded determinations as to the biologically activating efficacy of different light levels into account, without unnecessarily over-rating very high light levels, or under-rating (e.g., disregarding) lower levels of light exposure.

[0095] Herein, “ocular exposure” to environmental illumination is understood to occur when light from the environment reaches the retina of a person. Typically, however, the measurement used is not of that light level directly; rather, ambient light as detected (e.g., photometrically) by a suitably calibrated sensor in the vicinity of the eyes is used as the reference standard.

[0096] Nevertheless, in some embodiments, the estimate of light exposure takes into account factors such as estimated (optionally measured) eye pupil size (which may itself vary as a function of ocular exposure). In some embodiments, estimated ocular exposure takes into account light blocking and / or transmitting effects of eyewear such as ordinary glasses, sunglasses, and / or contact lenses. Optionally, ocular exposure takes into account differences in light sensitivity, e.g., due to relative thicknesses and / or transparencies of anterior segments of the eye. Insofar as a subject may potentially be determined to be more sensitive to developmental signaling from light (or to another effect of light exposure), this is optionally adjusted for.

[0097] Practically speaking, ocular exposure with potential preventative effects on the development of myopia may be understood to occur when performing waking activities (i.e., with the eyes open; e.g., play as opposed to sleeping) in an environment having a suitable level of illumination, typically but not necessarily an outdoors environment.

[0098] Additionally or alternatively to uses (e.g., prophylactic uses) relating to myopia, light-level effects related to vitamin D levels, skin conditions, mood, and / or UV sun damage are noted as potential applications of respectively and / or jointly applicable embodiments of the present disclosure.

[0099] Light Level Sensing and Estimation

[0100] From the full frequency range of daylight- spectrum light, a relatively narrow band primarily in the range perceived as blue colors is presently implicated in mediating ocular development. The range may be, for example, from about 470 nm down to a selected limit of detectability and / or effectiveness, e.g. , about 420 nm. For other conditions, other light wavelengths may be of greatest relevance; e.g., UV wavelength ranges for tracking skin exposure to solar radiation.

[0101] However, embodiments of the present disclosure, even when aimed at tracking exposure to a certain wavelength range are not necessarily limited to measuring and / or calibrated calculation of exposure of this frequency range. Light levels in one wavelength range may be determined using another wavelength range as a proxy (e.g., full spectrum visible white light exposure as a proxy for blue light exposure, assuming a relatively constant proportion of blue light to overall light sensed). Furthermore, embodiments of the present disclosure may be adapted to any suitable frequency range, according to developing understandings in the field regarding suitable light exposure levels and / or frequencies relating to any relevant biological, immunological, psychological, and / or developmental condition.

[0102] It may be understood that there are potentially a plurality of factors to calibrate for in a body-worn light sensor. Among these is that the body part to which the sensor is mounted is potentially exposed to light at a level different from that of the eye which is the target of interest. This may, moreover, be a varying relationship, even after stable factors such as pupil constriction response and individual sensitivities are taken into account, due simple to the movement of the wearer throughout their environment.

[0103] For example, for a wrist- worn device and a person performing activities in daylight: at any given moment, the light reaching the device is brighter or dimmer depending on both where the sun is relative to the person’s body (e.g., high in the sky or low; left, front, right, or behind), and where the device itself is relative to the body of the wearing person. Particularly for a wrist-worn device, relative device / body positioning may change often as the person goes about their activities. A sensor worn in a place with a relatively fixed relationship to the gaze of the wearer (e.g., on a headband, or on the torso) may measure light levels which are less variable in this sense, but still somewhat variable. For example, there may be differences in the efficacy of light depending on the sun’s angle: the eyes may be relatively shaded from the sun by headgear and / or facial structure when the sun is overhead, compared to daylight received when the sun is nearer to the horizon.

[0104] As a result (e.g., at least in some cases), momentarily- sensed light levels of a body-worn device potentially vary widely while the person remains with a substantially constant level of ocular exposure to environmental illumination. Directionality can be partially compensated for by providing the light sensor with a wide angle of light collection; however, with one side of the sensing device mounted against the body (and perhaps itself shaded by it in part), the light sensor is still liable to experiencing periods of greater or lesser illumination during free movement of the person wearing it, which does not necessarily correspond to what the eyes or other relevant area of the wearer’s body are experiencing.

[0105] Accordingly, the inventors have determined that over a period of activity spanning several light-level measurements, it may be beneficial to accuracy of the estimation of ocular exposure if the lowest momentary exposures of a light-sensing device are weighted less, or even ignored, at least under certain circumstances.

[0106] In some embodiments, measurements from the sensor (as applied to an exposure level and / or type of interest) are optionally adjusted in view of some illumination level used as a threshold and / or reference point.

[0107] For example: when measurements of light exposure are sufficiently high, an underestimate makes relatively little difference to a threshold-based exposure metric; e.g., full sunlight exposure may exceed the target threshold by 5-6 times or more, not necessarily with any greater estimated prophylactic effect on myopia. In such as case, measurements when device position is anywhere within that 5-6 fold range of exposure to be straightforwardly understood as indications of sufficient exposure.

[0108] Similarly, when all measurement are sufficiently low for a period of time, there may be a high degree of confidence that a given threshold of ocular exposure e.g., 10,000 lux) is not being reached; e.g., the multiplier which could bring brightest recent measurement up to the threshold may be unrealistically high to suppose that the device is merely shaded, while sufficient levels of ocular exposure nevertheless continue. For intermediate conditions of illumination (e.g., at the threshold illumination level or above it within a factor of about 2-3), and within a suitably-defined period of time (e.g., of 10-60 seconds), even a small number (e.g., one or two) threshold-exceeding measurements are optionally treated as a suitable basis for inferring ongoing sufficient ocular exposure. This is justified, for example, insofar as ocular exposure is dominated by the (relatively static) environmental conditions, while the measurement of a body-worn light sensor is prone to reductions (e.g., due to shading and / or position), but not to spuriously high intensities.

[0109] Under certain circumstances, however, it becomes potentially difficult to distinguish changes in illumination level from changes in body position. Furthermore, it may well be that a relevantly high- sensitivity position and / or orientation of the device does not occur with sufficient frequency to provide evidence that a certain threshold of ocular exposure is being exceeded, even when threshold-sufficient ocular exposure is indeed occurring.

[0110] Orientation-sensitive Light Exposure Estimation

[0111] However, the inventors have determined that sensor exposure to light may be usefully related to the orientation of the sensor in order to help characterize the current illumination of the environment.

[0112] Optionally, an orientation axis used in this determination is the orientation of the device with respect to the direction of gravity. For, e.g., a wrist- worn device, this allows distinguishing, for example, positions with the arm held down at the sides, positions with at least the forearm held about parallel with the ground (e.g., at a 90° angle outward from the shoulders), and positions with at least the forearm extending upward from the elbow. Positions in-between are also optionally distinguished. Since, e.g., the wrist also rotates by twisting of the forearm, there may optionally be ranges of angles around a second axis also distinguished.

[0113] Moreover, in some embodiments, magnetic orientation of the device is measured. This optionally used to allow distinguishing not just the orientation of the device relative to the body of the person wearing it, but also relative to the environment within which the person is carrying out activities. Optionally together with date and time of day information, this information may be used to estimate a current position of the sun relative to the device, allowing further refinement of device calibration. There may be coupling used computationally between these two sources of information; for example, an absolute uncertainty in compass orientation may be reduced somewhat by correlating light levels received from the sun with relative orientation of the device, adjusted for knowledge of the sun’s likely actual position in the sky. As part of a basic ocular exposure estimate algorithm, in some embodiments, the ocular exposure level estimated for a person is determined by taking the maximum illumination level of those recently measured. “Recently” may be set, e.g., as a period of 10-120 seconds or more (e.g., 60 seconds), after which use of a measurement is retired in favor of more recent measurements.

[0114] As an optional refinement to this, a repeated measurement at a same orientation of the sensing device (that is, “the same” within some range of similarity) may be treated as immediately replacing the previous measurement, even if it is lower in measured intensity. This potentially reduces a degree of exposure overestimation. There are various ways of making this replacement.

[0115] In a simple case, there may be distinguished two or three different categorically distinguished orientations, e.g., dividing 180° of device orientation with respect to the direction of gravity into thirds, with 0° to 60° (e.g., forearm pointed high or overhead) being one category, > 60° to 120° (e.g., forearm roughly horizontal) being a second category, and > 120°- 180° (e.g., forearm low or downward-pointing) being a third category.

[0116] In another case, measurements taken at a certain orientation may replace measurements taken within some range of orientations nearby, e.g., within ±10°, ±20°, ±30°, or a different range of angles. Optionally, newer measurements are blended with older measurements rather than replacing them outright, e.g., averaged, optionally averaged with a weighting which decreases according to measurement age. Average weighting may also vary as a function of angular distance; e.g., new measurements may replace older measurements more effectively when they are taken at exactly the same angle, and less effectively for somewhat different angles, e.g., by decreasing their weighting as the angular difference increases. Optionally, older measurements “age out” (are discounted / forgotten) faster when more newer corresponding measurements are available.

[0117] Optionally, and insofar as there may be no particular requirement for exposure to be calculated fully in real time, measurement values are filtered according to both earlier and later values, which potentially allows spuriously low measurement values for a given orientation and / or orientation category (e.g., due to a transient activity) to be determined and ignored. Optionally, both immediately updating and retrospectively filtered calculations are both performed, with corrected results eventually being what is used to produce the final recorded estimate of ocular exposure.

[0118] The “maximum value orientation” algorithm just outlined potentially works best when the activities of the device wearer move the device through a fairly full range of orientations over a relevant period of activity, or at least through a range of orientations resulting in at least one high (e.g., super-threshold) level of sensed illumination. To cover cases when this is not occurring (e.g., as can be determined by the device itself according to its own measurements of its orientation), optionally one or more other algorithms is brought into use, e.g., as fallbacks, and / or as main algorithms.

[0119] For example: in some embodiments, a sub-threshold measurement at a first orientation is nevertheless treated as indicative of sufficient ocular exposure, when it occurs with a certain linking relationship to (e.g., within a certain period of time such as between about 10 seconds and 10 minutes, for example, 20 seconds to 5 minutes, for example, between 30 seconds and 2 minutes) of a super-threshold measurement at a second orientation. For example, a measurement of 50% of threshold at the first orientation may be linked by proximity in time to a measurement of 150% of threshold at a second orientation. Since the two measurements occurred at “nearly the same time” (e.g., within several seconds of each other, and so likely in the same illumination environment), they both indicate a super-threshold level of ocular exposure. This, in effect, sets an associated threshold of sufficient ocular exposure as = 33% of the nominal target (e.g., 10,000 lux) for subsequent measurements at the first orientation. Optionally, the calibration is carried backward in time as well (e.g., in case any older calibrations are “aged out” by the ocular exposure tracking algorithm).

[0120] Optionally, these indirect calibrations relative to a nominal “maximum” illumination level are adjusted as new data arrives; e.g., calibration ratios are optionally preserved when new data indicates a higher or lower maximum light exposure level is appropriate for the device orientation that currently sets the controlling maximum value for the device. In some cases, there may be simultaneous partial updating of both the directly “sensed” value at an orientation and its associated calibration value, e.g., insofar as a measurement at a different orientation may have influences of either type, or both.

[0121] By implementing these concepts of dynamic time- and orientation- weighted calibrations, it may be understood that limitations in the available raw sensing data can be mitigated by coupling orientation sensing to illumination level sensing, potentially without requiring any special effort on the part of the wearer to provide an “optimal” sensing condition for the device.

[0122] ‘‘Prompted Orientation” Light Exposure Estimation

[0123] Nonetheless, in some embodiments, the device wearer is optionally prompted (or otherwise encouraged) to actively move the sensing device in a way which re-calibrates it. Additionally or alternatively, recalibration motion is optionally performed spontaneously by the user, e.g., by simply holding a hand up to ensure it is directly exposed to ambient daylight levels. Optionally, the device prompts the user (e.g., via an audible chirp, a haptic buzz, or other signal) to perform a calibrating action to confirm its state when it determines that it has been operating on insufficiently varied measurements for potentially long enough that the illumination situation might have changed unnoticed. For example, a value of 33% of the ocular exposure target for a certain orientation might have been earlier set as indicative of sufficient (super-threshold) ocular exposure. However, without any actual super-threshold measurement for a period of time long enough (e.g., 5-10 minutes), the value of this temporary calibration may be brought into question.

[0124] Optionally, the device prompts for such interaction (e.g., via an audible chirp or other signal) when it determines that it may have been inadvertently obscured, such as by a piece of clothing like a coat sleeve. For example, wide swings in measurement occurring during movement to a particular angle may be interpreted as indicative of a piece of clothing or other obstruction occasionally covering up over the light sensor inadvertently. Optionally, the device algorithm ignores sufficiently low measurement values (e.g., lOOx lower relative to the current maximum) as representing spurious quantities. Optionally, the device produces a notification (e.g., sound / vibration) when the history of measurements has gone on for too long a period without sufficiently valid and well-calibrated light measurements being available.

[0125] Optionally, the wearer is provided with an option to indicate and / or confirm entry into a relatively darkened area. This may include pressing a button on the device, or it may make use of the device sensors: for example, the wearer may deliberately hold their hand over the sensor for a period of time, may hold the device in a certain orientation for a period of time, or both (e.g., hands above head, with one hand hiding the sensor). Optionally, a time-varying pattern of such inputs is used, e.g., hiding and exposing the light sensor a plurality of times within a period of 1- 10 seconds.

[0126] It should be noted that any of these wearer actions, including wearing itself, may be “gamified” in some embodiments; e.g., the device may be designed to present itself as a character, force, or other entity (e.g., a “virtual plant”) with which the wearer interacts. For example, a character may be presented as “needing” a certain amount of light exposure (optionally as well as desiring “certainty” about its light environment), a perception which various prompts of the device (e.g., sounds, vibrations, and optionally character appearances on the device itself) are designed to reinforce. Alternatively, the character may be presented in the guise of a villain or force which is defeated by exposure to light; or of an ambivalent character having a nature which is influenced according to the use of the device. While myopia prophylaxis is presented herein as a particular use case of these approaches to light exposure estimation using a worn sensing device, it should be understood that they also apply, changed as appropriate, to sensing of light in the context of other conditions and / or potentially therapeutic applications, such as skin conditions, vitamin D levels, and / or mood treatments.

[0127] Conversely, deleterious effects (adverse physiological effects) of excessive exposure to sunlight (e.g., sun burn) are also well known. In some embodiments, light exposure is estimated and tracked in this respect as well, but in this case with a goal of informing about and / or limiting such excessive sun exposure. Since there are many ways of mitigating excessive sun exposure effects (e.g., covering clothing and sun protection products), this is optionally calibrated according to user preference, e.g., a parental setting available through a linking application. Optionally, exposure effects are tracked and estimated in conjunction with other measured values such as temperature; for example on a hotter day, sun exposure may be restricted more than on a cooler day, to mitigate risk of heat stroke and / or dehydration.

[0128] In some embodiments, excessive sun exposure tracking is available directly as an indication. In some embodiments, mitigation of excessive sun exposure is limited to the context of ensuring sufficient ocular exposure while discouraging excess; e.g., the “character” can express greatest satisfaction when light exposure levels are maintained at just above the threshold level, but somewhat less (or even “complaining”, such as using audio feedback) when exposure is excessive. Optionally, the device includes automatic and / or user-set variations in this exposuremoderating behavior according to season, location (longitude, latitude, and / or altitude) time of day, and / or optional wavelength- specific measurements of the levels of harmful radiation (e.g., UV). Optionally, such measurements are carried out and calibrated, changed as appropriate, as already described for the case of ocular exposure tracking.

[0129] In some embodiments, a light exposure measurement device tracks both prophylactic (beneficial) and deleterious (adverse) exposure effects of light, optionally each according to its own function (e.g., differences as a function of wavelength, intensity, and / or exposure time). The light measurement device optionally provides indications of both tracking results, e.g., in relative amounts such that a wearer can decide whether potential benefits continue to outweigh potential harm.

[0130] Before explaining at least one embodiment of the present disclosure in detail, it is to be understood that the present disclosure is not necessarily limited in its application to the details of construction and the arrangement of the components and / or methods set forth in the following description and / or illustrated in the drawings and / or given in the Examples. Features described in the current disclosure, including features of the invention, are capable of other embodiments or of being practiced or carried out in various ways.

[0131] Orientation- Adjusted Light Exposure Measurement

[0132] Reference is now made to Figures 1A-1D, which schematically illustrate a wrist- wearable light exposure measurement device 100, according to some embodiments of the present disclosure. As described, e.g., hereinabove, as well as in relation to other figures herein, light exposure measurement device 100 tracks light exposure according to an algorithm which compensates for light exposure differences between what is experienced by light exposure measurement device 100 at its worn location, at least one other body part and / or organ which is of particular interest for light exposure tracking. Moreover, the algorithm makes use of device orientation information as part of its implementation.

[0133] Figures 1A-1B show light exposure measurement device 100 in overview, from two different viewing angles. In some embodiments, light exposure measurement device 100 comprises a housing 101, which houses one or more of light- measuring sensor 103, light exposure indicator 102, and device orientation sensor 104.

[0134] In some embodiments, light-measuring sensor 103 is a dedicated light-level sensor, such as a photodiode. In some embodiments, light-measuring sensor 103 comprises a camera or other light-detecting device with a second purpose, which is accessed by a light exposure calculator 75 (e.g., Figure 4B) of light exposure measurement device 100 to make light level measurements. Light-measuring sensor 103 is optionally wavelength selective; e.g., it is sensitive to only a certain range of wavelengths, and / or it produces measurements which allow distinguishing of exposure to different wavelengths. In some embodiments, light-measuring sensor 103 is substantially non- selective for wavelengths. In such cases, and where wavelength is nevertheless considered important for an exposure effect being monitored, one wavelength band optionally is treated as standing in for another. For example, the blue light wavelength range is assumed to constitute a constant proportion of overall daylight, and / or a proportion which optionally varies according to determinations of factors such as cloud cover, either indirectly (e.g., from weather data), or based on interpretations of sensing data (e.g., noting that light is diffuse without a strong directionality of greatest intensity).

[0135] In some embodiments, device orientation sensor 104 preferably comprises a microelectromechanical system (MEMS) device which is able to track orientation, e.g., according to forces of acceleration exerted on it, and / or according to gyroscopic Coriolis forces responsive to a change in a plane of rotation and / or vibration. In some embodiments, device orientation sensor 104 senses its orientation in angular altitude and / or angular azimuth. In some embodiments, device orientation sensor 104 senses its orientation relative to the direction of gravity. Optionally, a magnetic compass is used to provide and / or supplement orientation information, e.g., to assist providing an absolute orientation of the device relative to the earth’s magnetic field. Optionally, orientation is sensed by any other suitable device, e.g., a set of switches which are activated by the pull of gravity on an internal element to close at different orientations of the device relative to the earth’s gravitational field.

[0136] In the example shown, light exposure measurement device 100 also comprises wrist band 105. Optionally, wrist band 105 comprises one or more additional sensors, for example, auxiliary light-measuring sensor 103B.

[0137] Figures 1C-1D show a face-on view of light exposure indicator 102. In some embodiments, the display of light exposure indicator 102 is configured to distinguish among a plurality of estimated light exposure levels.

[0138] Light exposure indicator 102 is optionally implemented, e.g., as a liquid crystal display (LCD). In the two examples shown, indicated exposure level 110A Figure 1C) has relatively few display segments active, while indicated exposure level HOD {Figure ID) has all of its display segments active. Display segments can be activated with any suitable indication resolution. For example, there may be four indication levels, consisting of nothing activated, just the central “face” area activated, the face plus one ring activated (as shown in Figure 1 C) or all rings activated (as shown in Figure ID). Additionally or alternatively, the rings can be gradually filled in, in any suitable pattern, to indicate progress toward sufficient exposure. Fully filled-in is not necessarily the level indication for “sufficient exposure”; e.g., the state of Figure 1 C could indicate “sufficient exposure”. Then, as light exposure continues, more segments activate. After a certain amount of additional exposure, activated segments are optionally distinguished in some manner (e.g., by their color or by flashing) to indicate that there is a danger of excessive light exposure, e.g., excessive exposure to ultraviolet which could lead to sunburn. Other variations on how light exposure indicator 102 may be configured and / or used to signal information are described, e.g., in relation to Figure 5A-7 herein, as well as in relation to Figure 4D.

[0139] In relation to wrist band 105, it may be noted that it is optionally open-sided. For example, wrist band 105 optionally comprises a flexible polymer {e.g., silicone rubber) and / or a flexible polymer coating such as silicone rubber over a relatively stiff core of metal or another material. This construction potentially allows easily slipping the device onto the wrist of a child, and may allow young children (e.g., as young as or younger than 6-7 years old) to place the device on their own wrist unassisted, with the device being sized to their wrists and hands so that it remains secured thereafter. However, it should be understood than any suitable configuration of wrist band 105 may be provided; for example, the full band types of Figures 8-9A, the decorative band types of Figure 11 A, and / or variously styled wrist bands of Figures 11B-11G. In some embodiments, wrist band 105 optionally supplements and / or is exchangeable with a wearable clip 1200, for example as described in relation to Figures 12A-13C.

[0140] In some embodiments, housing 101 is a self-contained module which can be switched among any of optionally several different wearables: for example, bands, clips for clothing and / or hair, pins, necklaces, or other means of securing housing 101 and its sensors and other hardware to a human body. Optionally, housing 101 is integrally formed with any one of such wearables. Optionally, housing 101, even if integrally formed with one wearable option, is also attachable to a second wearable to allow it to be worn in a different fashion.

[0141] Reference is now made to Figures 2A-2B, which schematically illustrate wearing of a wrist-wearable light exposure measurement device 100, according to some embodiments of the present disclosure. In the example of Figure 2A, light exposure measurement device 100 is worn on forearm 11 of the subject, at the wrist between forearm 11 and hand 10. Reference is also made to Figure 2C, which schematically illustrates light 90 impinging separately on a body organ 3 of interest (e.g., a retina 3A), and on light exposure measurement device 100 itself.

[0142] During activity of the wearer 5, the body part 4 to which the light exposure measurement device 100 is attached (in the illustrated example, a forearm 11), may change among several different angles with respect to a body organ 3 of particular interest for exposure tracking, e.g., an eye or retina. This creates a potential problem for a light exposure monitoring device, insofar as, e.g., the same level of illumination reaching the tracked body organ 3 of interest may correspond over time to several different levels of light measured by light exposure measurement device 100.

[0143] Depending on the subtended spatial angle of incoming light which is sensed by lightmeasuring sensor 103, there may be a range of measurement values produced from it, according to its orientation relative to light sources (e.g., the sun in particular, during outdoor use). While a light diffusion covering may somewhat mitigate this, such a solution does not necessarily compensate well for conditions when the device is shaded from direct light sources, e.g., by the body of the wearer. Furthermore, some repurposed sensors (e.g., cameras) may be unsuitable to cover with a light diffuser. Accordingly, embodiments of the present disclosure preferably make use of a compensation algorithm which converts light detected directly into an estimate of light exposure. In some embodiments, the compensation algorithm is based at least in part on sensing of an orientation of the light exposure measurement device 100 over time, e.g., using device orientation sensor 104.

[0144] Algorithm Concepts for Orientation- Adjusted Light Exposure Measurement

[0145] Reference is now made to Figure 3A, which is a schematic graph illustrating, for a single selected orientation 300B, sensed-orientation based light exposure calibration of a wrist-wearable light exposure measurement device 100, according to some embodiments of the present disclosure. Orientation 300B optionally corresponds to the horizontal position of forearm 11. For the sake of descriptions, orientation 300B is taken as a range of orientations, e.g., centered on horizontal, but extending on either side of it by, e.g. , 15°, 30°, or another amount. Optionally, actual measurements are recorded as accurately as device orientation sensor 104 allows.

[0146] In the graph shown, dotted line 302 indicates an estimated “sufficient” level of light exposure; that is, a light level high enough to count toward a targeted daily amount of bright light exposure. It should be understood, however, that the algorithm does not necessarily operate on a strict threshold basis. For example, light levels between dotted line 302A and dotted line 302B may all “count” toward meeting an exposure target, but in different amounts. The different amounts are optionally linear as a function of intensity, or any other shape. For example, light toward the dimmer side of the range may only just begin to count (e.g., only incrementally above 0 contribution), rising toward a maximum contribution. Optionally, light toward the brighter side of the range may be considered saturated or near- saturated in its potential beneficial effects, so that it is counted as no more beneficial per time period of exposure than some dimmer level of light exposure, or as more beneficial with a diminishing increment as a function of light intensity level.

[0147] Over time, (left-to-right axis of the Figure 3A), there are illustrated periods (with short “dashes” of trace data) where forearm 11 assumed substantially horizontal orientation 300B, and periods where it did not.

[0148] The light levels sensed during each period are not necessarily constant, nor are they necessarily overlapping among each other. For example, light level measurements during periods 304A, 304B, 304D are relatively high, compared to measurements during period 304C. In some embodiments, light exposure calculator 75 is configured to discount low light-level measurements during periods (e.g., periods of several second or minutes, for example, 30-120 seconds, or 1-10 minutes) in which higher light-level measurements are also obtained. A reason for this bias toward brighter measurements may be reasonably understood insofar as shading can easily result in under-measurement of light levels, while a high light level is more often reflective of unobstructed measurement conditions, similar to those experienced by a retina or other well-exposed portion of the body. The case of narrow-beam artificial illumination sources such as flashlights is excluded by this assumption, but also generally irrelevant to conditions of ordinary use.

[0149] In the example shown, trace 301 (dotted line) interpolates between various peak-brightness measurements. It should be noted that the interpolation optionally happens post hoc; e.g., the light levels estimated to pertain between measurement periods 304A and 304B are optionally set only after period 304B. This is reasonable particularly when the overall target of light exposure is the parameter of primary interest, since “real time” monitoring need not be precise in that case. The fitting function may be selected as any suitable function such as a spline function. The “decay” of the influence of a measurement (time past which a previous bright measurement is considered outdated) is optionally gradual over time by default, although optionally more abrupt when general conditions of data gathering indicate that the light environment of the use may have changed.

[0150] For example, the sweeping decline of light measured during period 304E is potentially indicative of the wearer changing environments (e.g., from outdoors to indoors, while opening a doorway). Without further later measurements of brighter light (e.g., during periods 304F, 304G) the algorithm optionally switches modes, inserting rapid light-level decay during period 301 A which reflects the presumptive change in conditions.

[0151] Reference is now made to Figure 3B, which is a schematic graph illustrating, for a full range of elevation angles 300A-300C, sensed-orientation based light exposure calibration of a wrist-wearable light exposure measurement device 100, according to some embodiments of the present disclosure.

[0152] Orientation 300A optionally corresponds to the pointing-down position of forearm 11, and orientation 300C optionally corresponds to the pointing-up position of forearm 11. Here, measurements are shown as if distinguished precisely by the angle at which they were measured; however, they are optionally binned in any suitable fashion, for example, collected into three bins divided by vertical lines 302C.

[0153] Gaps in the graph may indicate angles for which no measurement was taken (e.g., because the arm was moving too quickly relative to the sampling rate), and / or angles for which measurements were considered too sparse or unreliable (e.g., “noisy”) to be used. The various solid-line segments of the graph data e.g., segments 310, 306, and 308) should be understood as representing estimated light- level values “corrected” in some fashion; e.g., as described in relation to Figure 3A. Jointly, they should be understood as corresponding to a shared epoch in time; e.g., as light level values occurring without about 30-60 seconds of each other, within about 1-10 minutes of each other, or otherwise within a certain common window of time.

[0154] Even with these corrections applied, it may happen that measured light levels are different for different elevation angles, even though the actual light level of interest is (presumably) substantially unchanged for the epoch in question. In some embodiments, this presumption is applied as a calibration constraint, e.g., such that elevation angles contributing to segment 310 receive a gain factor which converts their light level measurements into a corrected value which is potentially more reflective of the light environment of interest for the target body organ 3. The arrows up toward line 305 leading from segment 310 and segment 308 are indicative of the effect of such a correction.

[0155] A potential advantage of this type of correction is that the sensing now does not require that the “brightest” angles be sampled as often - “dimmer” angles can suffice, for as long as it can be determined that the calibration factors applied are likely still valid. For example, the graph of line 301 in Figure 3A for a single, notionally “brightest” sensing angle could be confirmed and / or maintained according to sensing of potentially somewhat dimmer light at elevation orientations which, by calibration, are considered indicative of brighter ambient conditions.

[0156] Optionally, elevation angles for which sensed light levels are particularly low or otherwise at variance with expectation can be excluded from this multi-angle calibration approach. For example, segment 311 may be considered as indicative of light levels so dark that they no longer sufficiently correlate with ambient light conditions. This could happen, for example, due to an article of clothing such as a sleeve extending over light-measuring sensor 103. Exclusion may be according to a threshold 303, or another criterion.

[0157] Reference is now made to Figure 3C, which is a schematic graph illustrating, for a full range of azimuth angles 310, sensed-orientation based light exposure calibration of a wristwearable light exposure measurement device 100, according to some embodiments of the present disclosure.

[0158] Given that the sun 7 is a directional light source, there may be rises and falls in light level correlated with an azimuth orientation of light-measuring sensor 103. The levels indicated here may be considered as indicative of maximum corrected values, e.g., after taking into account conditions described in relation to Figures 3A-3B. Angle-dependent calibration corrections similar to those described in relation to Figure 3B are shown, for segment 316 and segment 314, to bring them into line with, e.g., the ambient light environment implied by the higher measurement values of segment 306. It should be understood, accordingly, that corrections may simultaneously take into account both azimuth and elevation angles. The correction function for a single angular axis may be determined from any suitable method of accounting for measurements taken throughout the range of the other angular axis. Noting that there may be angular “dead zones” (e.g., for when the forearm is held close to the body), there may be regions of 2-D angular space which are excluded from use in determining exposure levels, either because of presently observed irregularities in the data, or because of experimental evidence (e.g., during device testing) that those angles are less informative, and so should be ignored, rather than calibrated for.

[0159] With respect to azimuth angle, knowledge of the current position of the wearer in time and space may provide assistance to the light exposure calculator 75 in determining which measurements are likely to be meaningful. For example, in conditions of high sun, (e.g., near noon at lower latitudes), azimuth information may cease to be considered relevant, while in conditions of low sun (e.g. , nearer to sunrise / sunset and / or at higher latitudes and / or in wintertime conditions), azimuth information may be more important.

[0160] With reference to any of Figures 3A-3C, it should be understood that methods based on the illustrated principles are optionally carried out together or separately, and in any suitable order. Use of one of the angular axes is optionally omitted all together. Optionally, calculations corresponding to the self-history dependent single-orientation graph of Figure 3A are omitted, in favor, e.g., of the joint mutual calibration of Figure 3B.

[0161] In particular, it should be noted that the wrist-worn algorithmic approach is optionally adjusted for devices which are worn in another way, e.g., pinned to a shirt. In those cases, elevation angle may be less of a source of information than, e.g., azimuth angle. But azimuth angle may be more significant, since there could be larger periods of time during which the torso of the wearer shades the light exposure measurement device 100 from direct exposure to the sun.

[0162] It is also noted that there is no particular limitation to only a single light-measuring sensor 103. A wrist- worn light exposure measurement device 100, for example, may include one or more auxiliary sensors around its circumference, and these could be used to more consistently determine what the present “brightest” level of illumination is. Additionally or alternatively, users may choose to wear more than one device, e.g., one on each hand. Optionally, such devices are configured to be placed into communication with each other, so that their data is commonly available to at least one light exposure calculator 75 to refine its calculations. Secondary devices optionally are provided with lesser or different computational powers than primary devices. For example, a secondary device could be implemented as one or more sensors integrated with a handle of a carrying bag (e.g., a book bag of a young student).

[0163] Optionally, secondary devices comprise smart-watches (e.g., microprocessor-equipped watches) which can collect assisting data, whether or not they are themselves fully equipped with, e.g., the capabilities of a light exposure calculator 75. Optionally, a smart-watch is used as a primary and sole device (e.g., running software which configures it to run as a light exposure measurement device 100), or used as a primary device without a secondary device.

[0164] Functional Elements of a Light Exposure Measurement Device

[0165] Reference is now made to Figure 4A, which is a schematic block diagram illustrating functional-level components of a light exposure measurement device 100, according to some embodiments of the present disclosure. Shown at the center of the block diagram is processor 400. Memory 408 contains instructions 404 which instruct processor 400 to perform its various operations, as implemented for a particular embodiment. A measurement history 403 is preferably maintained in memory, although it is not necessarily a complete history; e.g., it optionally discards information as it become no-longer relevant for purposes of light exposure calculation. Optionally, light exposure calculator 75 is considered as comprising processor 400 and memory 408. Memory 408 may comprise other data, e.g., as described in relation to Figure 4B.

[0166] Measurements obtained (e.g., using processor 400; or separately, e.g., using a DSP chip writing directly into memory 408) include one or more light-measuring sensors 103, and one or more device orientation sensors 104. These sensors may be configured, for example, as described in relation to Figures 1A-1B.

[0167] In some embodiments, one or more additional sensors is provided. One of the illustrated examples is thermal sensor(s) 401. Thermal sensors 401 may be used in embodiments configured to track potentially deleterious over-exposure to ambient conditions with potentially adverse physiological effects. For example, a targeted level of outdoor-level light exposure considered prophylactic to myopia is potentially in conflict with the safety of the wearer when temperatures are above a certain level. In some embodiments, a light exposure measurement device 100 is configured to identify such exceptional circumstances, and alter its operation accordingly. For example, it may arbitrarily consider the targeted (minimum) light exposure dosage as having been met early, to avoid encouraging wearers to over-expose themselves to harsh environmental conditions. Additionally or alternatively, light exposure measurement device 100 may signal encouragement to take breaks from the high-temperature conditions, e.g., using one or more of display 102, haptics 406, and sound output 405; and / or signal encouragement to postpone outdoor activities until a later time when temperatures may have cooled off.

[0168] In some embodiments, the state of clock 410 (which is optionally set / maintained via time information collected through communication interface 409) is used to help estimate what modifications to default targets for light exposure are preferable and / or practical. Optionally, communication interface 409 is used to gather weather prediction information which is used in this assessment. Optionally, prompting by the device takes into account clouded and / or inclement days when low outdoor light levels are expected; e.g., by reducing requirements (for example, rather than encouraging outdoors activity in the rain), and / or preparing the user to expect that longer than ordinary light exposure times may be needed in order to reach a targeted level of daily light exposure.

[0169] Another illustrated example of an additional sensor is indicated as geolocation data source 402. Geolocation data source 402 may actually comprise any number of component sensors used to determine a present location of the light exposure measurement device 100. For example, the data may include information accessed by processor 400 via communication interface 409 which helps to identify the location of light exposure measurement device 100 according to the separately known locations of network nodes within which it is in communication. In some embodiments, geolocation data source 402 comprises a satellite positioning system radio interface (e.g., a GPS interface) and associated computational resources as appropriate. In some embodiments, geolocation data source 402 is used to set expected lighting conditions for the geographical location of the user, e.g., including hours of available daylight and / or expected position of the sun in the sky. The state of clock 410 is preferably also accessed in order to make use of such calculations of expected conditions.

[0170] Apart from its uses in modifying behavior of light exposure measurement device 100, communication interface 409 is optionally used to allow operating parameters to be set, and / or to communicate measured / estimated light exposure data to an external device; for example as described in relation to Figure 10B.

[0171] Communication of light exposure measurement device 100 with the wearer is optionally by any one or more of, e.g., light exposure indicator 102 (which may be a display including signaling indications beyond simply the amount of light exposure), haptics 406, and sound output 405. In implementations having “gamified” elements, the operation of any of these indicator elements may be used to convey “flavor” of the game. For example: sounds, haptic outputs and / or visual presentations appropriate to the simulated “personality” and / or “moods” of a character through which gamified elements of device operation are presented. Gamification does not necessarily use a simulated character intermediary; for example, it may be presented instead as a points-oriented system, and / or a goal-oriented system. Optionally, gamification is customized, e.g., to allow coupling reaching light exposure goals to user-selected (e.g., wearer- and / or caretaker-selected) rewards. It is noted that an aspect of gamification (e.g., for “fairness”) may include modification of expectations for light exposure in case external conditions do not allow safely achieving normally targeted light exposure levels. In some embodiments, gamification includes competitive or co-operative comparisons among wearers. For example, there may be an option to form group associations (e.g., via communication interface 409) for purposes of mutual encouragement.

[0172] It is also noted that as the stakes for gamification rise, there may be an added incentive to “cheat” the device. This is preferably kept in mind, e.g., by keeping the incentives themselves to relatively low-stakes consequences. Optionally there are included checks which detect at least some potential attempts to defeat the validity of device measurements. For example, the light exposure measurement device 100 may track whether it is actually kept in motion, whether measured light exposure levels are realistically likely given the present ambient conditions, and / or whether measured light exposure levels are varying in a plausible way over time.

[0173] Regarding group associations of wearers, communication interface 409 may also be useful in collecting and collating measured light exposure levels for a plurality of co-located device wearers. For periods when device wearers are known (e.g., according to geolocation data) to have been engaging in activities together, optionally sensor results from any of the wearers may be considered as applicable to any of the other wearers. Optionally, resulting corrections to measured exposure levels are made in real time via communication between the light exposure measurement devices 100 themselves. Optionally (e.g., to save battery life), coordination is via an external application, e.g., as described in relation to Figure 10B.

[0174] Reference is now made to Figure 4B, which is a schematic block diagram illustrating components and data structures for a light exposure calculator 75 of a light exposure measurement device 100, according to some embodiments of the present disclosure. Figure 4B repeats some elements of Figure 4A, with additional details of data elements which may assist in understanding aspects of the invention, and / or aspects of implementation usable in conjunction with the invention. In some embodiments, light exposure calculator 75 itself comprises at least processor 400 and associated instructions 404 stored in memory 408. As also noted in relation to Figure 4A, memory 408 may additionally include measurement history 403. This can include orientation measurements 68 (z.e., measurements made using device orientation sensors 104), light measurements 62 (z.e., measurements made using light-measuring sensor 103), and / or optional other measurements 64, which may include measurements of temperature, geolocation, or another sensed indication.

[0175] Light exposure calculator 75, in some embodiments, produces intermediate data structures in the form of calibration values. In particular, these may include orientation-dependent light measurement adjustments 63, the calculation of which is described, e.g., in relation to Figures 3A- 3C. Additionally, in some embodiments, other light measurement adjustments 63A may be generated and stored by light exposure calculator 75. These can be adjustments making use of environmental conditions to adjust how data are interpreted, and / or to adjust targeted light exposure levels. The adjustments may be based on data such as temperature measured by light exposure measurement device 100 itself, and / or based on data received via communication interface 409, e.g., regarding geolocation and / or local weather conditions.

[0176] Operating Methods of a Light Exposure Measurement Device

[0177] Reference is now made to Figure 4C, which is a schematic flow chart illustrating operation of a light exposure measurement device 100, according to some embodiments of the present disclosure.

[0178] It should be understood that the operations of the blocks of Figure 4C are presented in a conceptual order which is not necessarily the order in which operations are actually performed. For example, any of the measurements and calculation types may performed asynchronously to any or all of the others. As noted, e.g., in relation to Figures 3A-3C, calculations optionally operate on measurements at least in part retroactively, such that light exposure for a given time T between times T i and Tnis only calculated after at least some measurements made at or after time Tnare available.

[0179] At block 440, in some embodiments, light is measured. The light is measured using one or more light-measuring sensors 103. Optionally a single light-measuring sensor 103 located within a device housing 101 is used. Optionally, one or more additional light-measuring sensors 103B (e.g., as shown on Fig. IB) are provided, e.g., located so as to differentially sample ambient lighting conditions. At block 442, in some embodiments, light sensor orientation is measured. Light sensor orientation is measured using one or more device orientation sensors 104. Orientation may be measured, e.g., for one or two angular axes. Optionally measurements from a plurality of sensors are combined to determine orientation; e.g., magnetic compass measurements may be combined with inertial sensing.

[0180] At block 444, in some embodiments, the light-level measurements collected in block 440 are corrected using the light sensor orientation data collected in block 442. Examples of how correction may be performed are described, e.g., in relation to Figures 3A-3C. Guidelines for calculating these corrections may be summarized as follows. (1) Relatively brighter-light measurements take priority over relatively darker-light measurements, so long as the measurements can be treated as sufficiently corresponding (rule of “use the maximum value”). (2) Sufficiently corresponding measurements are those which can be determined as being taken under substantially the same ambient lighting conditions. As examples of how to determine this: one method is to use temporal proximity of the measurements as an indication of sufficient correspondence. Another is to measure non-light conditions such as temperature, and consider there to be a sufficient difference between, e.g., indoor and outdoor temperatures as to make them distinguishable. (3) Measurements at different sensor orientations, which are otherwise judged to be sufficiently corresponding, may be corrected to match each other, so as to allow them to each be treated as indicative of the same ambient lighting conditions applicable to a body organ 3 of interest for calculating light exposure levels. Conversely, measurements at substantially the same sensor orientation, which show different light levels, may be considered to be evidence of a change in ambient lighting conditions (indicating, as a result, that they are not sufficiently corresponding). (4) Measurements (e.g., outliers) for which sufficient correspondence cannot be reliably calculated, and / or which have values which cannot be reliably correlated with other measurements by calibration may be discarded. (5) Where there are gaps in the measurement record, data may be filled in by a method of interpolation. (6) User actions may be used to assist in determining appropriate light levels; e.g., users may (spontaneously or as prompted) confirm transitions from indoors to outdoors by their actions. Optionally, the user action involves manipulation of the orientation sensor readings; for example, holding the device in a particular orientation (e.g., arms above the head), or providing a pattern of orientations, (e.g., alternating positions of the forearm left / right and / or up / down).

[0181] The foregoing list of guidelines is non-exhaustive, and not every guideline is necessarily followed in each particular implementation of a light exposure measurement device 100. At block 446, in some embodiments, estimated exposure is updated. This may comprise updating estimated exposure with respect to a single standard targeted exposure level, e.g., estimating single day retinal exposure to light sufficiently bright to have an (estimated) biological effect on reducing myopia risk. Optionally, a plurality of exposure levels are estimated. For example, there may be a plurality of therapeutic light exposure estimates made, optionally selected with respect to a corresponding plurality conditions mentioned in the overview, or otherwise selected. Optionally, at least one estimated measure of potentially deleterious light exposure is updated, e.g., a measure corresponding to an estimated level of UV light exposure.

[0182] Furthermore, as part of block 446, estimated exposure may be communicated to the wearer during the period of light exposure by updating a light exposure indicator 102. Optionally, estimated exposure is communicated to a user (the wearer or another individual) via a data link through communication interface 409; for example, a data link to a personal communications device (e.g., cell phone), as described in relation to Figure 10B.

[0183] The operations of measuring light and orientation, correcting measurements, and updating estimated exposure repeat until a suitable condition is met, e.g., until the end of the day is reached, until it is night-time, until a targeted exposure level is reached, and / or until a user deactivates or resets the light exposure measurement device 100.

[0184] Reference is now made to Figure 4D, which is a schematic flow chart illustrating operation of a light exposure measurement device 100, including certain options for internal operations, according to some embodiments of the present disclosure.

[0185] Many of the operations of Figure 4D correspond in whole or in part to operations of Figure 4C. Some operations of Figure 4C are divided among a plurality of the operations of Figure 4D. Additional details are provided as non-limiting indications of how the operations of the blocks of Figure 4C could be implemented in more detail. For the sake of presentation, the operations are described as occurring in a continuous loop, but they are not necessarily synchronous.

[0186] At block 410, in some embodiments, a brightest-recent measurement is determined for the light exposure measurement device 100. “Recent” could mean “most recent”. Alternatively, it could be a relative recency, e.g. , a time period in the past for which the calculation of light exposure is affected by newer data. The calculations of block 410 may take into account any relevant calibrating data structures (e.g., including device orientation-dependent calibrating data structures, such as orientation-dependent light measurement adjustments 63). The brightest recent measurement may be understood as indicative of the “true” level of ambient light exposure to a fully exposed body part at the time associated with the measurement.

[0187] This is not necessarily the exposure level of any particular body part of interest. For example, it is optionally adjusted (e.g., as part of the operations of block 421) to correct for light level reductions experienced by a target body part 3 of interest. For example, exposure level may be reduced if the body part 3 is itself shaded and / or protected from light. When measuring skin exposure to sun UV radiation (as a more specific example), the reduction may take into account clothing worn and / or sunscreen protection applied, optionally as indicated to the light exposure measurement device 100 via user inputs such as menu selections, photographs (e.g., of the wearer and / or of the sunscreen product used), or another source of data.

[0188] At block 412, in some embodiments, operations to calculate calibrations among various orientations of light exposure measurement device 100 are optionally performed. These calculations may include, for example, consideration of any of the determinations described in relation to Figures 3A-3C.

[0189] At block 416, in some embodiments, optional user inputs to the light exposure measurement device 100 are received and included as modifying data in the operations of the light exposure measurement device 100. Optionally, these include user inputs to the light exposure measurement device 100 itself, e.g., via manipulation of orientation, using buttons of the device, and / or using a touch screen implementation of light exposure indicator 102. Optionally, these include external inputs, for example, device settings provided externally from an external device such as an application as described in relation to Figure 10B.

[0190] At block 418, in some embodiments, a determination is made as to whether the data available overall is sufficient to allow a meaningful determination of light exposure level for some period of device operation. If not, then the device may cycle back through block 414 (as next described) otherwise, the flowchart continues at block 420.

[0191] At block 414, in some embodiments, operations are performed to help resolve gaps in the light exposure record due to missing or otherwise invalid data. For example, the wearer may be prompted to perform explicit actions which allow the light exposure measurement device 100 to determine the current state of ambient lighting by exposing the sensor to the brightest available ambient light. Additionally or alternatively, the wearer may be prompted to provide to the light exposure measurement device 100 a selection which indicates directly whether the user is located indoors or outdoors, or otherwise describes ambient illumination which for whatever reason is not being correctly sensed. Optionally, device light exposure measurement device 100 simply supplies a fallback state of estimated illumination, e.g., based on what is considered to do have the least impact on the functionality of the device, and / or based on measurements which are nearby in time (before / after) the faulty data. From block 414, the flowchart returns to block 410.

[0192] Returning to block 420: in some embodiments, results of calculations at block 410 and / or block 412, and optionally user inputs 416, are inspected to determine if they amount to the creation of an “exposure event”. In a basic case, an exposure event results from a determination that a threshold of exposure has been reached which means that light exposure indicator 102 should be updated. This could be due to an accumulated value of light exposure as measured from block 410 reaching the threshold. Additionally or alternatively, user inputs from block 416, and / or calibration changes in block 412 could result in significant (potentially retroactive) changes to the interpretation of light-level measurements which leads to an exposure event. In some embodiments, exposure events comprise events which “undo” a previous increase in indicated exposure, e.g., due to recalculation in view of later-received data. In some embodiments, exposure events adjust something else about the light exposure measurement situation. For example, the event could indicate an adjustment to targeted exposure level (e.g., in view of what is safe and / or practical for the day).

[0193] If a relevant exposure event is determined, then the flowchart continues with block 421, in some embodiments. At this block, exposure indications are updated as appropriate.

[0194] While the exposure indications may be straightforward indications of progress (e.g., filling in of more indicator segments), exposure indications can be tailored as an important part of “gamification” of the light exposure measurement device 100. For example, a character represented by light exposure indicator 102 could express satisfaction, dissatisfaction, or another change in implied “state” which corresponds to the value of the change in light exposure with respect to the presently targeted goals for light exposure which are to be reached or avoided.

[0195] At block 422, in some embodiments, a determination is made as to whether the working environment of the light exposure measurement device 100 has changed in a relevant manner. This could be a literal change in physical environment (e.g., indoors vs. outdoors), or some change in the background conditions assumed by light exposure calculator 75, and against which light exposure calculations are performed. Either type of change is optionally represented by changing of a mode of operation (e.g., operation indoors or outdoors as a default assumption), and / or by changing parameters used in calculations.

[0196] For example, light exposure calculator 75 may be presently operating on the default assumption that the wearer is outdoors. This default assumption could influence, for example, how interpolations are made in cases where the available light sensing data is ambiguous. If the default assumption changes as a result of any of the various calculations and inputs assessed by light exposure calculator 75, this may have an impact on how exposure is calculated in the future, and optionally also have effects going back in time to when the transition to indoors (which is now confirmed) is likely to have actually happened.

[0197] Apart from light exposure itself, the light exposure measurement device 100 could indicate changes in modal status (e.g., indoors vs. outdoors), and / or changes in exposure goals (e.g., due to inputs which adjust targeted light exposure according to what is safe or realistic).

[0198] In some embodiments, non-light exposure information is optionally consulted in determining an environment change; e.g., scheduling of mealtimes, bedtimes, or other activities. While these activities are not in themselves providing of light exposure information, their scheduling optionally is provided to light exposure calculator 75 to assist in assessing what level of light exposure is realistically achievable given the other demands of the day, and / or to assist in selecting a degree of urgency with which “suggestions” by the device are presented in order to stimulate activities which will lead to a targeted level of light exposure. The urgency level of such suggestions and / or the relaxation of light exposure targets is optionally integrated into the “gamification” behavior of the light exposure measurement device 100.

[0199] Optionally, a level of wearer activity (e.g., as available from the dynamism of measurements made using device orientation sensors 104) is consulted as part of the assessment of “environment change”. This may be used to assess whether the wearer is tired, or perhaps bored. Optionally light exposure measurement device 100 produces wearer prompts appropriate to the situation, to assist in continuing light exposure for a longer period, and / or to bring the period of light exposure to an end, if appropriate. Prompts may include, for example, suggestions for games which are appropriate to the sensed activity level of the wearer; and / or direct suggestions, e.g., to go home. Prompts are optionally refined in relevance by preliminary questions asking, e.g., if the wearer is with companions, and / or if the wearer is feeling uncomfortable; e.g., tired, thirsty, or hungry. While the presentation of such prompts is not restricted to low-activity periods, a sensed state of low-activity may provide a suitable opportunity to better understand and compare the wearer’s present needs and priorities. Optionally, there are provided one or more high-activity modes; for example, modes in which tolerance of a wide range of light sensor readings for a particular sensor orientation is increased (e.g., rather than seen as a sign of a complex or inconsistent environment), potentially reducing “dead spots” in the data. If the environment has not changed, then the flowchart returns to block 410. If the environment has perhaps changed (but available data remains ambiguous), then optionally the flowchart returns to block 410 through block 414 and some type of wearer notification and / or adjustment which acknowledges the ambiguity and / or prompts the wearer to resolve it by providing more information.

[0200] Alternatively: at block 424, in some embodiments, device operating mode (e.g., “measurement expectations”) are adjusted appropriately to the detected change in the environment.

[0201] Next, at block 426, in some embodiments and for appropriate environment changes, the wearer is notified of the change in mode. After block 426, the flowchart also returns to block 410.

[0202] The flowchart ends upon any appropriate signal, e.g., as described in relation to Figure 4C.

[0203] Display Designs of a Light Exposure Measurement Device

[0204] Reference is now made to Figure 5A-5B, which schematically illustrate a light exposure indicator 102 of a light exposure measurement device 100, according to some embodiments of the present disclosure. Reference is also made to Figure 6, which schematically illustrates a light exposure indicator 102 of a light exposure measurement device 100, according to some embodiments of the present disclosure. Further reference is made to Figure 7, which schematically illustrates a light exposure indicator 102 of a light exposure measurement device 100, according to some embodiments of the present disclosure.

[0205] In the case of Figures 5A-5B, light exposure indicator 102 is implemented as a series segments which represent a growing plant. As measured light exposure approaches a targeted level, the plant increased in length. Optionally, e.g., at the threshold which completes the targeted level of light exposure, the plant blooms, or otherwise undergoes a transformation which indicates to the wearer that they have completed the targeted level of light exposure.

[0206] Figure 6 presents a variation of light exposure indicator 102 in the form of a schematically drawn face of dots (e.g., light emitting diodes). The face may comprise several different configurations (e.g., neutral, frowning, happy, sleepy, alert), and transition between them on the way to indicating sufficient light exposure. The indicators making up the face are optionally lit in different colors and / or with different intensities in order to convey information.

[0207] Figure 7 presents a variation of light exposure indicator 102, in the form of a dual-choice backlit display: one icon 701 indicating sufficient exposure (the upward pointing thumb, although any appropriate symbol may be substituted), and the other icon (if lit) indicating (as-yet) insufficient light exposure. Optionally, backlighting for the two icons is adjusted gradually as light exposure accumulates, e.g., adjusted in color and / or intensity. Optionally, there is at least one intermediate state in which both symbols are lit simultaneously to some amount.

[0208] Accessories of a Light Exposure Measurement Device

[0209] Reference is now made to Figure 8, which schematically illustrates a modular implementation of a watch band 810 and a device housing 801, of a light exposure measurement device 100, according to some embodiments of the present disclosure. Reference is also made to Figure 9A, which schematically illustrates an assembled state of the watch band 810 and the device housing 801, according to some embodiments of the present disclosure. Further reference is made to Figure 9B, which schematically illustrates an exploded view of the device housing 801, according to some embodiments of the present disclosure.

[0210] In the instance of Figure 8, the functional components of light exposure measurement device 100 are encapsulated in housing 101, but housing 101 is not integrally formed with its wrist band 810. Instead, it can be “popped out” of band 810, and optionally re-inserted into any other wrist band 810 or other device a design suitable to couple housing 101 to a wearer. Figure 9A shows housing 101 and wrist band 810 in their connected condition.

[0211] Figure 9B shows device housing 801 (an example of housing 101) in an exploded view which illustrates its components. Beneath (at least partially transparent) cover 910 is circuit board 911. Circuit board 911 may itself include the functions of light exposure indicator 102, and / or light exposure indicator 102 may be provided as an additional component, e.g., located between cover 910 and circuit board 911. Otherwise, circuit board 911 comprises elements of Figure 4A, e.g., processor 400, memory 408, and appropriate sensors, outputs and / or communication interface 409.

[0212] Rechargeable battery 912 provides power to the circuit elements of housing 101, while optional wireless charging coil 913 is configured to receive wirelessly transmitted power from a charging station such as that of Figure 10A.

[0213] Housing 801 is closed by mating casing 914 with cover 910.

[0214] Reference is now made to Figure 10A, which schematically illustrates a charging device 1001 for a light exposure measurement device 100, according to some embodiments of the present disclosure. In some embodiments, charging device 1001 is configured to interact with wireless charging coil 913 in order to provide charging power to rechargeable battery 912.

[0215] Reference is now made to Figure 10B, which schematically illustrates a remote application 1003 for a light exposure measurement device 100, according to some embodiments of the present disclosure. The remote application 1003 optionally runs on a personal communications device 1002 such as a cellular phone, and / or on another computing device such as a laptop or desktop PC. Optionally, remote application 1003 is implemented as a web application. Optionally, remote application 1003 is implemented as a device-hosted application.

[0216] Remote application 1003 is able to connect with light exposure measurement device 100 via its communication interface 409 (directly or indirectly) in order to provide one or more user functionalities. These optionally include one or more of the following.

[0217] Data tracking

[0218] Light exposure data can be accessed from light exposure measurement device 100, and optionally archived in whole or in part by the remote application 1003 and / or its supporting services. This is potentially useful in collecting information for studies, and / or for inspecting whether or not the device is reaching its targeted light exposure goals.

[0219] Localization

[0220] The light exposure measurement device 100 can optionally be localized with language and / or light exposure target information appropriate to the wearer / application user, and / or appropriate to the general physical location which the wearer frequents.

[0221] Measurement configuration

[0222] The light exposure measurement device 100 can optionally be reconfigured to measure light with different calibrating assumptions, e.g., presented as high-level options affecting option selection qualitatively (e.g., “more” or “less” sensitive), and / or low-level parameters. Optionally, hints are provided to the light exposure measurement device 100 which indicate how and where the device is worn. For example, it may be configured to assume (unless and until detected otherwise) that the device is worn on the wrist, on the torso, at the waist, or as part of a hair fastener. While the device may be able to self-determine which of these various use-modes are active (e.g., based on sensed patterns of motion and corresponding sensed levels of light), it is a potential advantage to have a setting which makes certain configuration more or less likely a priori. Similarly, there are optionally provided settings related to typical clothing worn by the wearer. For example, a long-sleeved coat may often tend to obscure the light-measuring sensor 103 of a wrist- worn light exposure measurement device 100. Taking this explicitly into account can potentially assist the light exposure calculator 75 in producing useful assessments of light level exposure.

[0223] Light exposure target configuration

[0224] The light exposure measurement device 100 can optionally be reconfigured to target light exposures at different levels for different wearers. Optionally, a balance of concern with over- exposure (e.g., excessive UV exposure) against concern for under-exposure (e.g., potentially myopia permissive under-exposure) can be set. Optionally, targets can be set for biological conditions of specific concern, while measurements aimed at other biological conditions can be deactivated.

[0225] Behavioral configuration

[0226] The light exposure measurement device 100 can optionally be configured with different “skins” according to user and / or wearer preference. These skins are optionally provided as packages of behaviors which map, e.g., exposure events, environment changes, alerts, and prompt interactions to specific presentations of light exposure indicator 102, and other interface indicators like haptics 406 and / or sound output 405. The skins may represent behaviors (e.g., personalities) of one or more characters, behaviors of a game, and / or represent simply a description of a user interface with a suitable combination of textual and graphical presentations. Optionally, a skin can be user modified according to parameters which the skin itself defines. For example, it may be configured to present non-light-exposure reminders, or not; it may be configured to adjust the urgency of its messages according to conditions, or not. Optionally (e.g., for advanced users), fully customized behavioral configuration can be read from a suitable data file (e.g., encoded in JSON, XML, YAML, CSS, XML or another data storage and exchange format), and / or optionally exchanged among users. Optionally, skins can include executable code, for example, written in JavaScript, Lua, or Python (for implementations of light exposure calculator 75 which include enough processing power and battery life to permit it).

[0227] Personalized data

[0228] Optionally, the light exposure measurement device 100 can be configured to take into account (and optionally also present) calendar-type information for the wearer such as daily and / or weekly schedules. Optionally, the light exposure measurement device 100 can be provided with personalized data such as names of the wearer and / or the wearer’s family and friends. Optionally, favorite activities of the wearer can be entered for mention in prompts which are aimed at encouraging activity in a particular (e.g., outdoors) environment.

[0229] Reference is now made to Figure 11A, which schematically illustrates fashion-band implementations of a light exposure measurement device 100, according to some embodiments of the present disclosure.

[0230] A modular implementation as described, e.g., in relation to the embodiments of Figures 8- 9B optionally allows wearer to select from among a plurality of form factors and decoration types in choosing what will secure the functional elements of light exposure measurement device 100 to the wearer. The various embodiments 1100A-1100E include the solid bracelet-like embodiments 1100A, HOOD, the more wristwatch-like embodiment 11OOB, a charm bracelet-like embodiment 1100C, and a sleeve-clipped version 1100E.

[0231] Reference is now made to Figures 11B-11G, which schematically illustrate alternative implementation styles for a housing 101 and wrist band 105 of a light exposure measurement device 100, according to some embodiments of the present disclosure.

[0232] Embodiment 1110 of light exposure measurement device 100 Figure 11B) takes the form of a smooth band incorporating an elongated display 102, similar, e.g.. to that of Figures 5A-5B. The light exposure indicators shown comprise small marks of any suitable shape {e.g., circles) which are added in sequence.

[0233] Embodiment 1120 of light exposure measurement device 100 {Figure 11 C) takes the form of a beaded bracelet incorporating an elongated display 102. The light exposure indicators shown comprise sunburst marks, added in sequence.

[0234] Embodiment 1130 of light exposure measurement device 100 {Figure HD) takes the form of a lozenge, which can be alternatively clipped in place, or integrated to a bracelet. In the embodiments shown, the light exposure indicators are activated in a sequence to complete a sunburst mark. The light-measuring sensor 103 is optionally provided with its own illumination aperture.

[0235] Embodiments 1140 and 1150 of light exposure measurement device 100 {Figures 11E- 11F) each take the form of a wrist band in the style of a bracelet watch band (watch band like in shape, but without a clasp) incorporating a roughly rectangular {Figure HE) or circular {Figure 11F) display 102. The light exposure indicator shown comprises a sunburst mark, the elements of which are optionally activated in sequence. The smiling face sun example of Figure 1 IF potentially adds appeal.

[0236] Embodiment 1160 of light exposure measurement device 100 {Figure 11G) takes the form of a wrist band in the style of a watch band incorporating an oblong display 102 incorporated into a smoothly curving “lozenge” shaped housing 101. The light exposure indicator shown comprises a sequence of dots, activated in sequence.

[0237] There is a potential advantage in using silicone rubber as at least a surface material for these embodiments, insofar as this is tough, easy to clean, accepts appealing (e.g., brightly colored) coloration, and moreover may make it easier for a child to handle and wear.

[0238] Reference is now made to Figures 12A-12C, which schematically illustrate a clothing clip 1200 that receives, by insertion, a housing 101 of a light exposure measurement device 100, according to some embodiments of the present disclosure. Figure 12A shows a side view including clip 1200; Figure 12B shows a front view emphasizing light exposure indicator 102 of device housing 101, and Figure 12C shows a back view with a portion of clip 1200 suppressed, through which a back of device housing 101 can be seen inserted to the case which is sized to receive it.

[0239] By comparison with the embodiment example of, e.g., Figures 1A-1D, it may be seen how a housing 101 can be provided which is interchangeably useable with a clip-style attachment, or a wrist band- style attachment.

[0240] Another form factor, used in some embodiments of the present disclosure, is a “smart ring”. Fig. IE shows an example of a smart ring 120 mounted on a finger. Optionally, the light sensor is mounted annularly on the ring so as to detect light from any orientation relative to the ring. Optionally, reference 122 indicates a window to a light guide which conveys light to an internal light sensor (not shown). A display may or may not be provided. Optionally, the ring communicates with a smartphone, for example, by Bluetooth or other wireless means and the smartphone (or other device) is used as a control and / or display interface. In some embodiments of the invention, the functional components for the light exposure measurement device 100 are integrated into one or more (finger) rings, and / or integrated into one or more modules configured to be attached to such rings. Using more than one ring may potentially reduce the burden on miniaturization of the device, by distributing it among a plurality of housings 101, although device communication may consequently become more of a drain on power resources.

[0241] Reference is now made to Figures 13A-13C, which schematically illustrate a clothing clip 1200 which receives by insertion a housing 101 of a light exposure measurement device 100, and is also usable with a wrist band 1212, according to some embodiments of the present disclosure.

[0242] In this example, housing 101 does not need to be removed from clip 1200 in order to couple it to a wrist band 1212. Instead e.g., as shown in Figures 13A-13C), the spring element of the clip 1200 can be passed over the back of the wrist band 1212, securing the device housing 101 in place. Optionally, wrist band 1212 is provided with appropriately shaped indentations to allow accommodating clip 1200 without it protruding into the wrist of the wearer.

[0243] General

[0244] As used herein with reference to quantity or value, the term “about” means “within ±10% of’.

[0245] The terms “comprises”, “comprising”, “includes”, “including”, “having” and their conjugates mean: “including but not limited to”.

[0246] The term “consisting of’ means: “including and limited to”. The term “consisting essentially of’ means that the composition, method or structure may include additional ingredients, steps and / or parts, but only if the additional ingredients, steps and / or parts do not materially alter the basic and novel characteristics of the claimed composition, method or structure.

[0247] As used herein, the singular form “a”, “an” and “the” include plural references unless the context clearly dictates otherwise. For example, the term “a compound” or “at least one compound” may include a plurality of compounds, including mixtures thereof.

[0248] The words “example” and “exemplary” are used herein to mean “serving as an example, instance or illustration”. Any embodiment described as an “example” or “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments and / or to exclude the incorporation of features from other embodiments.

[0249] The word “optionally” is used herein to mean “is provided in some embodiments and not provided in other embodiments”. Any particular embodiment of the present disclosure may include a plurality of “optional” features except insofar as such features conflict.

[0250] As used herein the term “method” refers to manners, means, techniques and procedures for accomplishing a given task including, but not limited to, those manners, means, techniques and procedures either known to, or readily developed from known manners, means, techniques and procedures by practitioners of the chemical, pharmacological, biological, biochemical and medical arts.

[0251] As used herein, the term “treating” includes abrogating, substantially inhibiting, slowing or reversing the progression of a condition, substantially ameliorating clinical or aesthetical symptoms of a condition or substantially preventing the appearance of clinical or aesthetical symptoms of a condition.

[0252] Throughout this application, embodiments may be presented with reference to a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of descriptions of the present disclosure. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as “from 1 to 6” should be considered to have specifically disclosed subranges such as “from 1 to 3”, “from 1 to 4”, “from 1 to 5”, “from 2 to 4”, “from 2 to 6”, “from 3 to 6”, etc.; as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range. Whenever a numerical range is indicated herein (for example “10-15”, “10 to 15”, or any pair of numbers linked by these another such range indication), it is meant to include any number (fractional or integral) within the indicated range limits, including the range limits, unless the context clearly dictates otherwise. The phrases “range / ranging / ranges between” a first indicate number and a second indicate number and “range / ranging / ranges from” a first indicate number “to”, “up to”, “until” or “through” (or another such range-indicating term) a second indicate number are used herein interchangeably and are meant to include the first and second indicated numbers and all the fractional and integral numbers therebetween.

[0253] Although descriptions of the present disclosure are provided in conjunction with specific embodiments, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.

[0254] It is appreciated that certain features which are, for clarity, described in the present disclosure in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the present disclosure. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.

[0255] It is the intent of the applicant(s) that all publications, patents and patent applications referred to in this specification are to be incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually noted when referenced that it is to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present disclosure. To the extent that section headings are used, they should not be construed as necessarily limiting. In addition, any priority document(s) of this application is / are hereby incorporated herein by reference in its / their entirety.

[0256] Reference numbers in the claims should be considered as providing guidance for exemplary embodiments and assistance for reading the claims, but should not be considered as necessarily limiting the scope of the claims beyond the scope provided by the words alone.

Claims

WHAT IS CLAIMED IS :

1. A body-wearable light exposure monitoring device (100), comprising: a housing (101) including: a light- measuring sensor (103), a device orientation sensor (104), housed to move with the light-measuring sensor (103) while measuring an orientation of the light- measuring sensor (103), a light exposure indicator (102), and a light exposure calculator (75); wherein the light exposure calculator (75): accesses light measurements (62) from the light-measuring sensor (103) and orientation measurements (68) from the device orientation sensor (104), and uses the light measurements (62) to calculate an estimated level of physiologically active exposure to light (80), and provides the estimated level of physiologically active exposure to light to the light exposure indicator (102); wherein the light exposure calculator (75) uses the orientation measurements to determine adjustments (63) used to calculate the estimated level of physiologically active exposure to light (80).

2. The device (100) of claim 1, wherein the light exposure calculator (75) calculates the estimated level of physiologically active exposure to light (80) for a first body part (3), using the orientation measurements (68) as indications of the orientation of a second body part (4).

3. The device (100) of claim 2, wherein the first body organ (3) comprises a retina (3 A), and the second body organ (4) comprises a limb.

4. The device (100) of claim 2, wherein the first body organ (3) comprises a retina (3 A), and the second body organ (4) comprises a head or torso.

5. The device (100) of claim 2, wherein the first body organ comprises exposed skin surface, and the second body organ comprises a limb, head, or torso.

6. The device (100) of any one of claims 1-4, wherein the light exposure indicator (102) relates the estimated level of physiologically active exposure to light (80) to a daily period of exposure to light estimated to provide adequate protection from an adverse physiological condition.

7. The device (100) of claim 6, wherein the adverse physiological condition comprises myopia.

8. The device (100) of any one of claims 6-7, wherein the adverse physiological condition comprises an affective disorder.

9. The device (100) of any one of claims 6-8, wherein the adverse physiological condition comprises a vitamin deficiency.

10. The device (100) of any one of claims 6-9, wherein the light exposure calculator (75) estimates a contribution of light to provide adequate protection from the adverse physiological condition according to brightness.

11. The device (100) of claim 10, wherein the calculator uses a brightness threshold to estimate the contribution of light to provide adequate protection from the adverse physiological condition.

12. The device (100) of any one of claims 10-11, wherein the brightness threshold corresponds to exposure to outdoors daylight.

13. The device (100) of claim 10, wherein the calculator estimates the contribution of light to provide adequate protection from the adverse physiological condition according to a weighted function including two or more brightnesses contributing non-zero contributions to the weighted function.

14. The device (100) of any one of claims 6-13, wherein the light exposure calculator (75) estimates the contribution of light to provide adequate protection from the adverse physiological condition according to duration of exposure to light.

15. The device (100) of any one of claims 6-14, wherein the light exposure calculator (75) estimates a contribution of light to provide adequate protection from the adverse physiological condition according to light wavelength.

16. The device (100) of claim 15, wherein the light-measuring sensor (103) selectively measures a range of wavelengths estimated to confer protection from the adverse physiological condition.

17. The device (100) of claim 15, wherein the light- measuring sensor (103) measures a range of wavelengths not selective for wavelengths estimated to confer protection from the adverse physiological condition, and the light exposure calculator (75) estimates exposure to a range of wavelengths estimated to confer protection from the adverse physiological condition using the wavelength non-selective measurements.

18. The device (100) of any one of claims 1-17, wherein the light exposure calculator (75) estimates a contribution of light to a potentially adverse physiological condition.

19. The device (100) of claim 18, wherein the adverse physiological condition comprises ultraviolet skin damage.

20. The device (100) of any one of claims 18-19, wherein the adverse physiological condition comprises heat stroke.

21. The device (100) of any one of claims 18-20, comprising a temperature sensor, wherein the light exposure calculator (75) uses the temperature sensor to determine adjustments to the estimated level of physiologically active exposure to light (80).

22. The device (100) of any one of claims 18-19, wherein the light exposure calculator (75) estimates a contribution of light to the potential adverse physiological condition according to one or more of the group consisting of: light brightness, light wavelength, and length of light exposure.

23. The device (100) of any one of claims 18-22, when dependent on any one of claims 6-17, wherein a first range of estimated light exposure is estimated to contribute to the adverse physiological condition to which light exposure is estimated to contribute, a secondrange of estimated light exposure is estimated to contribute protection to the adverse physiological condition for which light exposure is estimated to provide protection, and the light exposure provides to the light exposure indicator (102) indications estimating at least relative amounts exposure for each of the first and second ranges of estimated light exposure.

24. The device (100) of any one of claims 1-23, wherein the light exposure calculator (75) maintains a record of when light was measured at different orientations of the light- measuring sensor (103), determines when measurements made at an orientation are in need of updating, and prompts a wearer of the device (100) to change the orientation of the light-measuring sensor (103) accordingly.

25. The device (100) of claim 24, wherein the light exposure calculator (75) determines that measurements made at an orientation are in need of updating according to one or more of: whether light estimated to be productive of physiological activity has been measured at any orientation within a sufficiently recent time period; whether light brightness may potentially be at a current level estimated to be productive of physiological activity exists at the orientation, but measurements of light brightness at the orientation are not current.

26. The device (100) of any one of claims 1-25, wherein the light exposure calculator (75) operates in a plurality of modes, the modes comprising at least: a daylight active mode, wherein the light exposure calculator (75) is biased to expect measurements of bright light; an inactive mode, wherein the light exposure calculator (75) is biased to expect measurements of dim light.

27. The device (100) of claim 26, wherein, in the daylight active mode, the light exposure calculator (75) assumes continuation of bright conditions for a longer period without direct measurement confirmation from the light- measuring sensor (103) than compared to the inactive mode.

28. The device (100) of any one of claims 26-27, wherein, in the daylight active mode, the light exposure calculator (75) more actively prompts the wearer to adjust theorientation of the light measuring sensor to maintain confirmation of exposure to bright light than compared to the inactive mode.

29. The device (100) of any one of claims 26-28, wherein the light exposure calculator (75) changes and / or maintains modes according to one or more of: how dynamically the orientation of the device (100) changes over time, an input from the user comprising manual operation of a control of the device (100), an input from the user comprising orienting the device (100) to provide an input signal to the light exposure calculator (75), and a temporal pattern of exposure to brighter and / or darker light.

30. The device (100) of any one of claims 1-29, wherein the light exposure calculator (75): for each of a plurality of orientation ranges (69), determines, respectively: a sensed light level (6A) indicated by one or more of the light measurements (62), said one or more of the light measurements (62) being associated in time with one or more of the orientation measurements (68) corresponding to the orientation range; selects from among the sensed light levels (6 A) a maximum light level (6D); and uses the maximum light level (6D) to determine the adjustments (63) used to calculate the estimated level of physiologically active exposure to light (80).

31. The device (100) of claim 30, wherein the light exposure calculator (75) modifies the light levels (6A) according to indications by one or more additional light measurements (62A) and their respective additional orientation measurements (68A), and the maximum light level (6D) is re-selected accordingly.

32. The device (100) of claim 31, wherein the light exposure calculator (75) modifies the light levels (6A) by replacing them with the one or more additional light measurements (62 A), according to their associated respective additional orientation measurements.

33. The device (100) of claim 31, wherein the light exposure calculator (75) modifies the light levels (6A) by weighted adjustment from the one or more additional light measurements (62 A), according to their associated respective additional orientation measurements.

34. The device (100) of claim 33, wherein the weighted adjustment is weighted according to at least one of distance in time before and distance in time after the one or more additional light measurements (62A).

35. The device (100) of any one of claims 33-34, wherein the weighted adjustment is weighted according to at least one of angular azimuth distance and angular altitude distance from one or more of the plurality of orientation ranges of the respective additional orientation measurements.

36. The device (100) of any one of claims 33-35, wherein the weighted adjustment is weighted to increase the influence of relatively higher light levels, compared to relatively lower light levels.

37. The device (100) of any one of claims 30-36, wherein the plurality of orientation ranges comprise at least two angular altitude ranges distinguished by different angular altitudes.

38. The device (100) of claim 37, wherein the at least two angular altitude ranges comprise a first angular altitude range oriented most downward, a second angular altitude range oriented most upward, and a third angular altitude range in between the first and second ranges.

39. The device (100) of any one of claims 37-38, wherein the at least two angular altitude ranges comprise at least eight angular altitude ranges arranged from most downward to most upward.

40. The device (100) of any one of claims 30-39, wherein the plurality of orientation ranges comprise at least two azimuth ranges distinguished by different angular azimuths.

41. The device (100) of claim 40, wherein the at least two azimuth ranges comprise a first azimuth range oriented more toward a position of the sun, and a second range oriented less toward the position of the sun.

42. The device (100) of any one of claims 40-41, wherein the at least two azimuth ranges comprise at least eight angular altitude ranges arranged from most downward to most upward.

43. The device (100) of any one of claims 1-42, wherein the device orientation sensor (104) comprises one or more of the group consisting of: a gyroscope, an accelerometer, and a magnetic compass.

44. The device (100) of any one of claims 1-43, wherein the adjustments correspond to adjustments in an estimated brightness of the light indicated by the light measurements (62).

45. A method of providing an estimated level of physiologically active exposure to light, the method comprising: accessing, by a light exposure calculator (75) comprising a processor (400): light measurements (62) made by a light-measuring sensor (103), and orientation measurements (68) made by a device orientation sensor (104), positioned to measure an orientation (67) of the light-measuring sensor (103); calculating, by the processor and using the light measurements (62), the estimated level of physiologically active exposure to light, the calculating comprising using the orientation measurements to determine adjustments (63) to the estimated level.

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