Lighting apparatus

Abstract

The present application disclosed a lighting apparatus, for example a surgical headlamp to be worn by a surgeon during an operation, that includes an emitter, a detector, and a controller. The emitter emits light at an adjustable first intensity over a first field-of-view (FOV) according to an intensity parameter received from the controller. The detector has a second FOV that overlaps the first FOV and measures the intensity of light received within the second FOV and provides this measurement to the controller. The controller computes the intensity parameter based in part on the measurement provided by the detector.

Description

LIGHTING APPARATUSCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to, and the benefit of, U.S. Provisional Application No. 63 / 750,327, entitled “LIGHTING APPARATUS” and filed January 27, 2025, and to U.S. Provisional Application No. 63 / 767,886, entitled “LIGHTING APPARATUS” and filed March 6, 2025, the disclosures of which are herein incorporated by this reference in their entirety.BACKGROUNDField

[0002] This disclosure relates to lighting apparatuses and. in particular, a surgical headlamp having automatic intensity control.Description of Related Art

[0003] Surgeons often wear a high-power headlamp while they are operating to better illuminate the surgical site to provide the best visualization of the surfaces on which they are operating, compared to relying on room lights that may be blocked by the surgeon’s head. With conventional headlamps, the brightness of the projected light incident on the surgical site changes as the surgeon moves his head. Compensating for these changes in brightness requires the surgeon to adjust the headlamp to vary its projected intensity. Such adjustments may be distracting, cumbersome, and difficult during a surgical procedure.

[0004] Face shields are often used in certain surgical procedures, for example the enclosed hoods worn in orthopedic surgery, wherein the headlamp may be worn under the hood and projects light through the face shield. It is common for blood and tissue to splatter onto the outer surface of the face shield. Material that is within the optical path of the light projected by the headlamp may heat up and singe or bum, potentially damaging the face shield at a location that the surgeon may not see.

[0005] Therefore, in view of the above, there is a need for an improved surgical headlamp that addresses these deficiencies.SUMMARY

[0006] A surgical headlamp is disclosed that is configured to automatically adjust the intensity of the emitted light so as to maintain a constant level of illumination of a designated site, e.g., a surgical site, while the surgeon moves relative to the surgical site.

[0007] In an aspect, the present disclosure provides for a lighting apparatus comprising a housing, an emitter, a detector, and a controller. The emitter may be fixedly attached to the housing and configured to emit light at an adjustable first intensity, receive a first signal comprising a first parameter, and adjust the first intensity based in part on the first parameter. The first detector may be fixedly attached to the housing and configured to measure a second parameter associated with the emitted light and provide a second signal comprising the second parameter. The controller may have a signal connection to both the emitter and the first detector and may be configured to receive the second signal from the first detector, compute a value of the first parameter based in part on a comparison of the received second parameter to a setpoint, and provide the first signal to the emitter.

[0008] According to various embodiments, the second parameter may comprise at least one of a distance from the emitter to a first projected area illuminated by the emitted light and a second intensity of light received by the first detector. The emitter may emit light in a first field-of-view (FOV) that may include the first projected area. The first detector may receive light from a second FOV that overlaps the first FOV such that the second FOV includes a portion of the first projected area.

[0009] According to various embodiments, the lighting apparatus may comprise a second detector. The second detector may be fixedly attached to the housing and may have a signal connection with the controller. The second detector may be configured to measure a third intensity of light, compute a third parameter associated with the measured third intensity', and provide a third signal comprising the third parameter. The emitter may emit light in a first FOV that may include a first projected area. The first detector may receive light from a second FOV that overlaps the first FOV such that the second FOV includes a portion of the first projected area. The second detector may receive light from a third FOV that includes at least one of a portion of the first projected area and a portion of the second projected area illuminated by the first FOV on a face shield being worn by a user who is also wearing the lighting apparatus. The first detector may be configured to measure a second intensity of light only within a portion of a first band of light selected from a spectral group consisting of a visible band of light and aninfrared (IR) band of light. The second detector may be configured to measure the third intensity of light only within a portion of a second band of light selected from the spectral group and different from the first band of light.fOOlO] According to various embodiments, the controller may be configured to execute a safety action selected from a safety group if the second parameter is greater than a first safety threshold or the third parameter is greater than a second safety threshold. The safety group may consist of setting the first parameter to a first safety value that will cause the emitter to reduce the first intensity to a predetermined safe level, turning off power to the emitter, and closing a shutter that is disposed in the first FOV. The controller may be further configured to latch the first parameter, when a safety value is selected for the first parameter, such that the selected safety action is continued until either the controller receives a reset input or a safety timer that started when the selected safety action was executed times out.

[0011] According to various embodiments, the controller may be configured to execute a safety action selected from a safety group if the second parameter is greater than a first safety threshold. The safety group may consist of setting the first parameter to a first safety value that will cause the emitter to reduce the first intensity to a predetermined safe level, turning off the power to the emitter, and closing a shutter that is disposed in a first FOV. The controller may¬ be further configured to latch the first parameter, when a safety value is selected for the first parameter, such that the selected safety action is continued until either the controller receives a reset input or a safety timer that started when the selected safety- action was executed runs out.

[0012] According to various embodiments, the housing may be configured to be attached to an item of headgear configured to be worn by a user. The lighting apparatus may further comprise a user interface. The user interface may be in signal connection with the controller and may be configured to provide a fourth signal comprising at least one of a first input associated with the first intensity- when a new setting of a variable control is selected by a user and a second input associated with the setpoint when the user activates an actuator. The controller may be configured to receive the fourth signal from the user interface and adjust at least one of the first parameter and the setpoint based in part on the first input, upon receipt of the first input. The controller may be configured to adjust the setpoint to match a current value of the second parameter, upon receipt of the second input. The controller may be configured to compare the second parameter to a first safety threshold and execute a safety action selected from a safety group if the second parameter is greater than the first safety threshold. The safetygroup may consist of setting the first parameter to a first safety value that will cause the emitter to reduce the first intensity to a predetermined safe level, turning off power to the emitter, and closing a shutter that is disposed in the first FOV.[00131 In another aspect, the present disclosure provides a method comprising emitting light at an adjustable first intensity by an emitter, adjusting the first intensity based in part on a first parameter, measuring a second parameter associated with the emitted light, and computing the first parameter based in part on a comparison of the second parameter to a setpoint.

[0014] According to various embodiments, the light may be emitted over a first FOV. The second parameter may comprise at least one of a distance from the emitter to a first projected area illuminated by the emitted light and a second intensity’ of light received within a second FOV that partially overlaps the first FOV. The method may include measuring a third intensity of light received within a third FOV that includes at least one of a portion of the first projected area and a portion of a second projected area illuminated by the first FOV on a face shield being worn by a user who is also wearing the emitter. The method may include computing a third parameter associated with the measured third intensity. The method may include adjusting the first parameter based in part on one or more of a comparison of the second parameter to a setpoint and a comparison of the third parameter to a threshold.

[0015] According to various embodiments, the method may include comparing at least one of the second parameter and the third parameter to a respective first safety threshold and a second safety threshold. The method may include executing a safety action selected from a safety group if the second parameter is greater than the first safety threshold or the third parameter is greater than the second safety threshold. The safety' group may consist of setting the first parameter to a first safety value that will cause the emitter to reduce the first intensity to a predetermined safe level, turning off power to the emitter, and closing a shutter that is disposed in the first FOV. The second intensity of light may be measured only within a portion of a first band of light selected from a spectral group consisting of a visible band of light and an IR band of light. The third intensity of light may be measured only within a portion of a second band of light selected from the spectral group and different from the first band of light.BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Aspects of the 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 are for purposes of illustrativediscussion of aspects of the disclosure. The description and the drawings, considered alone and together, make apparent to those skilled in the art how aspects of the disclosure may be practiced.

[0017] Fig. 1 depicts a surgeon wearing a surgical headlamp under a protective hood, according to an example embodiment.

[0018] Fig. 2 is a schematic cross-sectional view of an example headlamp, according to another example embodiment.

[0019] Fig. 3 depicts a surgeon operating on a patient using a surgical headlamp, according to an example embodiment.

[0020] Fig. 4 depicts a perspective view of the light beam projected by a headlamp and the field-of-view of an exemplary' sensor disposed within the headlamp, according to another example embodiment.

[0021] Fig. 5 depicts a schematic view of a surgeon wearing a surgical headlamp under a protective hood that has a contaminant on the face shield, according to another example embodiment.

[0022] Fig. 6 depicts a block diagram of an exemplary lamp, according to an example embodiment.

[0023] Fig. 7 depicts a flowchart of an example method of controlling a lamp, according to an example embodiment.

[0024] Fig. 8 depicts an exemplary feedback control system for controlling a lamp, according to another example embodiment.DETAILED DESCRIPTION

[0025] This description is intended to illustrate some particular embodiments of the disclosure and not to exhaustively specify all permutations, combinations and variations thereof. Features illustrated with respect to one embodiment may be incorporated into other embodiments, and features illustrated with respect to a particular embodiment may be deleted from that embodiment. In addition, numerous variations and additions to the various embodiments suggested herein will be apparent to those skilled in the art in light of the instant disclosure and do not depart from the instant disclosure. In some instances, well-known structures, interfaces, and processes have not been shown in detail in order not to unnecessarily obscure the invention.It is intended that no part of this specification be construed to affect a disavowal of any part of the full scope of the invention.Problem

[0026] Surgeons often wear a high-power headlamp while they are operating in order to better illuminate the surgical site on which they are operating, rather than relying on room lights that may be blocked by the surgeon's head, may be at the incorrect angle to illuminate a surgical site such as a deep hole or cavity, or otherwise fail to provide ideal illumination for visualization of the surgical field. Conventional headlamps have a drawback in this situation, however, as the brightness of the illuminated site varies as the surgeon moves his head or body relative to the surgical site. The intensity of light incident on a surface varies with the inverse square of the distance from the light source to the surface, so even small changes in the surgeon’s position cause significant changes in brightness. At the extreme, the projected light can undesirably heat the illuminated surface if the surgeon, either deliberately or inadvertently, moves too close to the surface. The same problem can occur when the surgeon deliberately turns their head away from the surgical field and inadvertently projects the light on a surface closer than the safe working distance, e.g.. their own surgical gown or that of a colleague, resulting in the material of the surface, e.g., the fabric of a gown, beginning to singe. Compensating for these changes requires the surgeon to repeatedly adjust the intensity of the light source, which can be cumbersome and takes away from the surgeon's concentration on the procedure.

[0027] In certain procedures surgeons wear transparent face shields to reduce contamination of the surgical site and to protect the surgeon from blood splatter, debris, and airborne contaminates. For example, an orthopedic surgeon often wears the surgical headlamp under an enclosed protective hood that has a transparent face shield. The hood both reduces the risk of contamination of the surgical site by the surgeon and protects the surgeon from blood and tissue that may be splattered during the procedure, e.g., while cutting a bone with a surgical saw. If debris such as blood, tissue, or bone cement has splattered and stuck to the face shield in the area where the light projected by the headlamp passes through the face shield, the debris will absorb energy from the light and heat up. The debris will bum if its temperature gets too high and may damage the face shield, and may do so in a way that the surgeon cannot see because it is hidden from their view, or the area is too bright to resolve.Solution

[0028] Both of the problems described above are addressed by the systems and methods disclosed herein. To maintain a constant illumination of a surgical site, an optical sensing system measures the intensity of a portion of light reflected from a portion of the area illuminated by the light source. In certain embodiments, the optical sensing system includes optical elements that limit the FOV so that its sensor receives only light reflected from the illuminated area. This measurement may be compared to a setpoint and the intensity of the emitter may be adjusted to maintain the illumination approximately the same as the surgeon moves. To avoid having debris bum onto the face shield, a similar optical sensing system measures the intensity of a portion of light reflected from the splatter. This measurement may be compared to a setpoint and, in certain embodiments, the intensity of the emitted light may¬ be temporarily or permanently reduced to avoid burning the debris.Terminology7

[0029] Unless otherwise defined herein, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology- used in the description of the disclosure herein is for the purpose of describing particular aspects or embodiments only and is not intended to be limiting of the disclosure. References to techniques employed herein are intended to refer to the techniques as commonly understood in the art, including variations on those techniques or substitutions of equivalent techniques that would be apparent to one of skill in the art.

[0030] As used within this disclosure, the term “light” means electromagnetic energy- having a wavelength within the range, or band, of 10 nm to 1 mm, wherein “ultraviolet” (UV) light is generally associated with the range of approximately 10-400 nm also referred to as the UV band, “visible” light is generally associated with the range of approximately 400-750 nm also referred to as the visible band, and “infrared” (IR) light is generally associated with the range of approximately 750 nm-1 mm also referred to as the IR band. A plurality of the UV band, visible band, IR band, and other bands having defined wavelength ranges, are referred to as a spectral group.

[0031] As used within this disclosure, the term “optical” refers to aspects of elements that produce, manipulate, or receive light, e.g, an emitter, an aperture, a filter, a shutter, a lens, a mirror, and a detector.

[0032] As used within this disclosure, the term “shutter’" refers to a mechanism configured to selectively allow or block all or a portion of a beam of light. In certain embodiments, the shutter comprises a moving element having an “open” position that allows the entire beam of light to pass and a “closed” position that prevents any of the beam of light to pass. In certain embodiments, the shutter comprises a sliding element. In certain embodiments, the shutter comprises a rotating element. In certain embodiments, the shutter comprises multiple elements, e.g., a camera iris, that move in a coordinated fashion to block the entire beam of light. Moreover, the shutter may comprise any suitable device for controlling passage of all or a portion of a beam of light through the shutter.

[0033] As used within this disclosure, the phrase “field-of-view” (FOV) applies to both the light projected by an emitter and the region over which light is received by a sensor or detector. In certain embodiments, a FOV is redirected or reshaped, for example by a mirror or lens, and the FOV includes the entire length inclusive of the modifying element unless stated otherwise. A surface illuminated by the light emitted within a FOV is considered to be within the FOV of the emitter. A surface from which light is detected is considered to be within the FOV of the detector.

[0034] As used within this disclosure, the term “aperture” refers to any element of an optical system that limits the FOV, including optical stops, adjustable irises, baffles, and tubular passages having a diameter and length that restrict the angle of light that travels through the passage without intersecting a wall of the passage.

[0035] As used within this disclosure, the term "intensity" means the optical energy per a defined area or solid angle. In certain example embodiments, an optical filter may band filter the energy (or light) restricting the frequency of light that passes through the filter reaches the sensor 231 to a selected band, e.g.. the intensity of visible light.

[0036] As used within this disclosure, the phrase “fixedly attached” means that the two elements are disposed in a known and fixed position and orientation with respect to each other when attached yet may be separable or permanently attached to their respective mating surfaces.

[0037] Fig. 1 depicts a surgeon 10 wearing a surgical headlamp 110 under a protective hood 100, in accordance with the present disclosure. The hood 100 comprises a transparent face shield 102. The headlamp 110 may be attached to a headband 112 worn by the surgeon under the hood 100. The headlamp 110 may be connected by a cable (not visible in Fig. 1) to a beltpack (not visible in Fig. 1) that may provide power and may control the intensity of the light emitted by the headlamp 110.

[0038] In a broader context, the headlamp 110 may comprise an example emitter configured to emit light having an adjustable intensity over a FOV, as discussed further with respect to Fig. 4. In various embodiments, the headlamp 110 may be configured to be attached to an item of headgear worn by the user, including but not limited to a headband, cap, helmet or hood support frame, protective glasses, or surgical magnifiers.

[0039] Fig. 2 is a schematic cross-sectional view of an exemplary lamp 200, in accordance with the present disclosure. In various embodiments, the lamp 200 may comprise a housing 210 that may enclose an emitter 220, a first detector 230, and a second detector 240.

[0040] In various embodiments, the housing 210 may comprise multiple parts, e.g., a body and a cap suitable to provide access to the interior for assembly and / or service. In various embodiments, a heatsink 228 may be thermally coupled to the emitter source 221 to dissipate heat. The modules and elements of the lamp 200 may be arranged or combined in any suitable arrangement in accordance with various embodiments. Furthermore, other components, e.g., an air circulating fan, may be included in the lamp, but are not shown in Fig. 2 in order to clarify the disclosure.

[0041] The example emitter 220 may comprise an emitter source 221, e.g., a light emitting diode (LED), a focusing element 222, e.g., one or more lenses, an aperture 224, e.g., a field stop, and optical filter 226, e.g., a sheet of material or coating that blocks a band light. The module may have an optical axis 201 along which light may be emitted over a first FOV. The elements of emitter 220 may be fixedly attached to the housing 210. In various embodiments, one or more of these elements 222, 224, 226 may comprise multiple parts, e.g., filter 226 may comprise an IR filter and a UV filter. In various embodiments, one or more of the elements 222, 224, 226 may be omitted.

[0042] The exemplary lamp 200 may comprise two detectors 230, 240 which may be configured to sense light within a first FOV and a second FOV that each overlap the FOV of the emitter 220. In various embodiments, the FOV of one of the detectors 230, 240 may intersect the emitter FOV at the face shield of a protective hood worn by the surgeon w hile the FOV of the other detector may intersect the emitter FOV at the area of interest, e.g., a surgical site. While the example detectors 230, 240 are shown in FIG. 2 as integral with the lamp 200,equivalent detectors may be external to and / or separate from the housing 210 in various embodiments.

[0043] The example first detector 230 may comprise an optical sensor 231, a focusing element 232, an aperture 234, e.g. the passage that connects the focusing element 232 to the sensor 231, and an optical filter 236. Tn various embodiments, the first detector 230 may comprise a separate field stop. In various embodiments, the first detector may have an FOV aligned with an axis 202 that may be parallel with the pointing axis 201. In various embodiments, the axis 202 is not parallel with emitter axis 201. In various embodiments, axis 202 may intersect axis 201 at a point outside the housing 210, e.g., the nominal working distance from the emitter to the area of interest, e.g., the surgical site. In various embodiments, the optical sensor 231 may generate a signal that is representative of, and based in part on, the intensity' of the light received by the sensor 231 that may be passed to a controller (discussed further with respect to Fig. 6). In various embodiments, the optical filter 236 may restrict the frequency of light that reaches the sensor 231 to a selected band. In various embodiments, the selected band may be a portion of the visible band. In various embodiments, the selected band may be a portion of the IR band. In various embodiments, the selected band may comprise a portion of the visible band and a portion of the IR band.

[0044] The second detector 240 may comprise an optical sensor 241, a focusing element 242, a filter 244, and an aperture 246, e.g.. the passage that connects the focusing element 242 to the sensor 241. In various embodiments, the second detector 240 may comprise a separate field stop. In various embodiments, the second detector may have a FOV aligned with an axis 203 that is not parallel with the pointing axis 201. In various embodiments, axis 203 may intersect pointing axis 201 at a point outside the housing 210. In various embodiments, axis 203 may intersect axis 201 at the nominal clearance distance between the emitter and the face shield of a protective hood being worn by the user, as shown in Fig. 1. In various embodiments, the axis 203 may be non-parallel with pointing axis 201 but does not intersect pointing axis 201. In various embodiments, axis 203 may be parallel to pointing axis 201. In various embodiments, the optical sensor 241 may be sensitive to a portion of the IR band of light and may generate a signal that is representative of the intensity of the light received by the sensor 241, and may pass the signal to a controller (discussed further with respect to Fig. 6). In various embodiments, the optical filter 244 may restrict the frequency of light that reaches the sensor 241 to a selected band. In various embodiments, the selected band may be limited to a portion of the visible band. In various embodiments, the selected band may be limited to a portion ofthe IR band. In various embodiments, the selected band may comprise a portion of the visible band and a portion of the IR band.

[0045] In various embodiments, one or more of the optical axes 201, 202, and 203 may be bent or folded, e.g, reflected by a minor or refracted by a lens.

[0046] Fig. 3 depicts a surgeon 10 operating on a patient 20 using a surgical headlamp 110 (hidden under protective hood 100 in Fig. 3), in accordance with various embodiments. While looking at the surgical site 22, the light emitted by the headlamp 110 may have a FOV 310 with an associated pointing axis 312 that illuminates a projected area 320 of the patient 20. In various embodiments, the light beam may be a right circular cone, i.e., a circular cross-section symmetric about the pointing axis 312. In various embodiments, the light beam may be an oblique cone, i. e. , a circular cross-section not symmetric about the pointing axis 312. In various embodiments, the light beam may be a polyhedron, e.g., a rectangle or irregular shape having straight or curved sides through which the pointing axis 312 passes. Light from the headlamp 110 may be reflected by the surfaces, e.g., the skin and surgical drapes, within the projected area 320 and a portion of this reflected light may be directed back toward the headlamp 110. In circumstances where there are multiple light sources illuminating the projected area 320, a portion of the light from the other sources may also be reflected toward the headlamp 110.

[0047] Fig. 4 depicts a perspective view of a light beam having a FOV 422 projected by an emitter 420 of a lamp 400 and the FOV 432 of an exemplary detector 430 disposed within the lamp 400. In various embodiments, the emitter 420 and the detector 430 may be separate devices that may be disposed in a fixed position and orientation relative to each other. The emitter FOV 422 may have a pointing axis 424 and may illuminate a projected area 426 on a surface (not show n in Fig. 4). The detector FOV 432 may have an axis 434 and may collect light reflected from observed area 436. In various embodiments, axis 434 may be approximately parallel with pointing axis 424. In various embodiments, axis 434 may be nonparallel with pointing axis 424. In various embodiments, one or more of the axes 424, 434 may be folded by a mirror (not shown in Fig. 4) and may comprise multiple straight portions. In various embodiments, observed area 436 may be fully contained within projected area 426. In various embodiments, observed area 436 may partially overlap area 426. In various embodiments, the amount of overlap of observed area 436 with area 426 may be dependent upon the distance of the lamp 400 from the illuminated surface. In various embodiments, the projected area 426 illuminated by the emitter 420 may be fully contained within observed area 436 within the FOV of detector 430 at a defined distance.

[0048] In various embodiments, the second FOV 432 may be disposed relative to the first FOV 422 such that the observed projected area 436 will include at least a portion of the projected area 426 illuminated by light within the first FOV 422 on a surface positioned at a selected distance from the emitter 420. In various embodiments, with reference to Fig. 3, the selected distance may be the nominal distance from the emitter of the headlamp 110 to an area of interest 22.

[0049] In various embodiments, the lamp 400 may be configured to provide a predetermined intensity of illumination for a projected area 426 at a predetermined distance from the emitter 420 to the projected area 426. In various embodiments, the intensity of light measured by detector 430 may be compared to a fixed setpoint, for example, the fixed setpoint may be a constant value embedded in the software or memory or selected at the factory during manufacture.

[0050] In various embodiments, the intensity of emitter 420 may be controlled based on the distance from the emitter 420 to the projected area 426. In various embodiments, detector 430 may be configured to measure the distance from the emitter 420 to the projected area 426. In various embodiments, the measured distance may be compared to a look-up table and a desired intensity associated with the measured distance may be retrieved. In various embodiments, the measured distance may be entered into an equation that calculates the desired intensity of the emitter.

[0051] In various embodiments, with reference to Fig. 3, the selected distance may be a clearance distance from the emitter of headlamp 110 to a face shield of the protective hood 100 being worn by user and the projected area 426 may be disposed on the face shield illuminated by light within the first FOV 422. In various embodiments, the observed area 436 may be larger than area 426 and area 426 may be completely disposed within observed area 436. In various embodiments, more than 80% of area 426 may be disposed within observed area 436. In various embodiments, more than 50% of area 426 may be disposed within observed area 436. In various embodiments, more than 25% of area 426 may be disposed within observed area 436. In various embodiments, more than 1% of area 426 may be disposed within observed area 436.

[0052] In certain embodiments, emitter 420 and detector 430 may be configured to measure the distance from the emitter 420 to the surface within the observed area 436. In certain embodiments, the light emitted by emitter 420 may comprise a modulation, e.g., a pulse of adifferent intensity or an embedded binary signal, and the detector 430 may be configured to detect the modulation of the reflected light, wherein the time delay between the emission of the modulation and the detection of the modulation enables a time-of-flight calculation of the distance. In various embodiments, the “zero” and “one” states of the binary signal may be provided as different intensities of the emitted light. In various embodiments, the “zero” and “one” states of the binary signal may be provided as different durations of a first intensity emitted light that may otherwise be emitted at a second intensity that is different from the first intensity. In various embodiments, the distance measurement may be provided by a second emitter-detector pair (not shown in Fig. 4) wherein the emitter emits a pulse of unmodulated light and the detector senses the arrival of the light pulse. In various embodiments, the distance measurement may be provided by a second emitter-detector pair (not shown in Fig. 4) operating on a different principal, e.g., emitting and detecting an ultrasonic pulse or signal, or utilizing a different type of light, e.g., emitter 420 & detector 430 operate in the visible band and the second emitter-detector pair operate in the IR band. In various embodiments, the distance measurement may be provided by any suitable device or plurality of devices for measuring a distance.

[0053] In certain environments, there may be other light sources that shine directly into or may be reflected into the detector 430. The other light sources can create an erroneous signal that the light provided by the emitter 420 is higher than the desired intensity. The other light sources may continuously shine into the detector 430, e.g., a high-intensity room light, or may- only occasionally shine into the detector 430, e.g., a headlamp worn by another clinician. It is undesirable for the emitter 420 to be modulated in response to the erroneous signal.

[0054] In certain embodiments, the user 10 may select a “background” intensity level, e.g., using the user interface 624 of Fig. 6. The background intensity level may compensate for the portion of the light sensed by the detector 430 that is provided by the other light sources, e.g., sources other than emitter 420 in the current environment. In an example where the room light is bright, the user 10 may select a background intensity level where the intensity of the reflected room light creates a signal that is below the selected level, and where only a signal above the selected level causes an adjustment of the intensity of emitter 420, e.g., the selected background intensity level is subtracted from the instantaneous measurement signal provided by the detector 430 before it is compared to the target intensity level.

[0055] In certain environments, e.g., wherein another clinician occasionally shines their headlamp onto the lamp 400 and induces a spike in the measured light intensity, it may bedesirable to measure the instantaneous background level of light, for example, to determine whether the emitter 420 is the source of the spike in the light intensity measured by detector 430. In certain embodiments, the system can be configured, e.g., implemented in the programming of controller 622 of Fig. 6, to turn the emitter 420 off for a short time interval, e.g., 10 milliseconds. The time interval can be selected such that it is imperceptible to the user 10 but is long enough for the detector 430 to measure the background light intensity while the emitter 420 is off. The system, e.g., the controller 622, may then turn the emitter 420 on again. The emitter 420 may be turned on at either the original intensity, for example if the background light intensity' is the source of the spike, or at a reduced level, for example if the emitter 420 is determined to be contributing to the spike. In certain embodiments, this modulation of the emitter 420, i.e., periodically turning the emitter 420 of to measure the background light level, is performed only when the measured intensity exceeds a predefined threshold. In certain embodiments, this modulation of the emitter 420 can be performed periodically to determine the background level of light. In certain embodiments, the frequency of the background measurement can be once per second, 5 times per second (5Hz), 10 times per second (10 Hz), or a frequency above 10 Hz. In certain embodiments, the frequency of the background intensity measurement and the duration of the background measurement period, i.e., when the emitter 420 is off, are selected to be imperceptible by the user 10.

[0056] Fig. 5 depicts a schematic view of a surgeon 10 wearing a surgical headlamp 510 under a protective hood 100 that has a contaminant 540 on the face shield 102, in accordance with various embodiments. The headlamp 510 may comprise an emitter 520 and a detector 530 that may be sensitive only to light in the IR band. The FOV 532 of the detector 530 and the FOV 522 of the light beam projected by the emitter 520 may intersect a common projected area on the face shield 102.

[0057] In various embodiments, a contaminant 540, e.g., blood or tissue from the patient or a surgical material, is disposed on the face shield 102 within the common projected area. Light from the emitter 520 may be absorbed by the contaminant 540 thereby heating the contaminant 540, which then may radiate IR energy' 542 proportional to the temperature of the contaminant 540. At an elevated temperature, the contaminant 540 may bond to the face shield 102 or soften and / or distort the face shield 102. If the temperature of the contaminant 540 exceeds a phasetransition temperature of the contaminant 540, the contaminant 540 will undergo pyrolysis wherein the organic components break down into simpler molecules, leading to the formationof gases, liquids, e.g. tars and oils, and solid residues, e.g, char or ash, and the resulting liquids and solids may adhere to the face shield 102.

[0058] In various embodiments, the contaminant 540 may be located on a portion of the face shield 102 that is not visible to the surgeon 10. It may therefore be advantageous to have a detector with a FOV that overlaps the portion of the face shield 102, i.e., the projected area, through which the emitted light passes and to automatically detect the presence of a hot contaminant within this projected area.

[0059] The IR energy' 542 radiated by the contaminant 540, as well as IR energy radiated by the face shield 102, within the FOV 532 may be measured by the detector 530. The total received IR energy may be measured and converted to a signal, which may be passed to a controller (not shown in Fig. 5). The controller may be configured to compare the magnitude of the signal to a sensing threshold. If the signal exceeds the sensing threshold, the intensity of the light emitted by the emitter 520 may be adjusted, e.g., reduced to a safe level or turned off. In various embodiments, the IR energy may be measured by a second detector (not shown in Fig. 5) that may be functionally equivalent to detector 530. In various embodiments, the second detector may be configured to sense only' IR light while detector 530 may be configured to sense only visible light.

[0060] Selection of the sensing threshold may account for the contaminant 540 covering less than the entire common projected area, the IR energy radiated by a clean face shield under the same intensity of projected light from the emitter 520, and the relationship between the temperature of the contaminant 540 and the radiated IR energy 542. In various embodiments, selection of the sensing threshold may be partially based on experimental data. In various embodiments, selection of the sensing threshold may be partially based on calculations.

[0061] In various embodiments, the controller may integrate the received signal over a selected time duration, e.g., from “now ” backward in time for the selected duration, to produce a time-intensity value that may be compared to a threshold. In various embodiments, a short exposure to a high intensity' of light and a longer exposure to a lower intensity would be considered equivalent. This type of signal processing may avoid the system switching the lamp off if the beam is momentarily obstructed, e.g., the surgeon's hand passes through the beam and obstructs the beam for a fraction of a second, as the potential injury is low for such a short exposure. In various embodiments, this integral may be calculated as a “moving average,”wherein the intensity received by the detector 530 is measured at a regular interval and a selected number of the most-recent measurements are averaged.

[0062] In various embodiments, headlamps may use light emitters of such a high intensity that they can singe or bum a material if it is placed too close to the emitter. Various embodiments of the disclosed headlamp provide protection from accidental burning of objects by the light emitted by the headlamp. As an example, a surgeon may be wearing a surgical headlamp 510 (without a hood) and take the headlamp / headband off and place it facing downward on a nearby draped table without turning the emitter 520 off. The beam of a high-intensity emitter 520 can easily raise the temperature of the draped table surface to its ignition temperature within seconds. To address this risk, various embodiments of the disclosed system are configured such that the detector 530 may measure one or both of visible light and / or IR energy from objects that are proximate to the emitter, for example a table surface on which the headlamp is lying, and the system may compare the measured intensity to a safety threshold, and may turn the emitter down to a predetermined safe level, e.g.. 20% of the maximum intensity of the emitter, or may turn the emitter off if the safety threshold is exceeded. In various embodiments, the controller latches the emitter in the reduced-intensity or “off” condition until the system is manually reset, e.g., the surgeon presses a “reset” button on a user interface (discussed further with respect to Fig. 6). In various embodiments, the controller latches the emitter in the reduced-intensity or “off’ condition until a safety timer times out. The safety7timer may be configured at a pre-set value, for example, the safety timer may be, in various embodiments, configured such that the light reflected by the table surface may be much brighter than the setpoint selected for a more distance proj ected area 320, as the amount of light increases exponentially as the distance is reduced, such that a detector 530 configured to sense visible light may shut off the emitter 520 almost immediately when placed face down on a table.

[0063] In various embodiments, a single detector 530 may implement, in combination with a controller, both a constant intensity control and a safety monitor control. In various embodiments, the detector 530 may be sensitive to portions of both the visible band of light and the IR band of light. The intensity of a portion of the visible band may be compared to a setpoint and the operation of the emitter 520 may be adjusted to maintain a constant visible intensity. At about the same time, or immediately prior to, or immediately after, the intensity of a portion of the IR band may be compared to a threshold and a safety action may be executed if the IR intensity7exceeds the threshold. The safety action may be selected from a safety groupthat includes, for example, reducing the intensity of the light emitted by the emitter 520 to a predetermined safe level, turning off power to the emitter 520. at least partially blocking the FOV 522, e.g., closing a shutter that is disposed in internally within the emitter 520 or externally in the FOV 522 of the emitter 520, and any other suitable safety action. In various embodiments, the safety monitor control may be implemented by comparing the intensity7of a portion of the visible band to the threshold. In various embodiments, the safety monitor control may be implemented by comparing the intensity of a combination of a portion of the visible band and a portion of the IR band to the threshold.

[0064] Fig. 6 depicts a block diagram of an exemplary lighting apparatus 600, in accordance with the present disclosure. In various embodiments, the lighting apparatus 600 may comprise a headpiece 610 and a belt pack 620. Certain functional blocks, e.g., a communication module that transmits and / or receives information from a remote system, are not shown for clarity. Although described herein as belt pack 620, in various embodiments any of the functions or components of belt pack 620 may also be performed, for example, by a back pack, by a head pack, or may be integral to headpiece 610.

[0065] The headpiece 610 may comprise an emitter 612, a first optical system including a first detector 614, e.g., sensitive only to visible light, and a second optical system including a second detector 616, e.g, sensitive only to IR light. Each of emitter 612, the first optical system, and the second optical system have a signal connection, e.g, can communicate wirelessly or over an electrical or optical cable, with controller 622 of the belt pack 620. Although described herein as within belt pack 620, controller 622 may be separate from belt pack 620. For example, controller 622 may be within headpiece 610. The controller 622 may also have a signal connection with user interface 624.

[0066] The emitter 612 may be configured to emit light at an adjustable intensity over a FOV, receive a signal that comprises a first parameter associated with the intensity of the emitted light, and adjust the emitted intensity based in part on the received first parameter.

[0067] The first detector 614 has a second FOV and may be attached to the housing in a fixed position and orientation relative to the emitter 612 such that the second FOV at least partially overlaps the first FOV. In various embodiments, the first detector may be configured to measure an intensity of light received within the second FOV, compute a second parameter based in part on the measured intensity; and provide a second signal comprising the second parameter. In various embodiments, the second FOV may be disposed relative to the first FOVsuch that the second FOV may include at least a portion of a first projected area illuminated by light within the first FOV on a surface positioned at a selected working distance from the emitter 612. In various embodiments, the working distance may be a nominal distance from the emitter to an area of interest while the lighting apparatus 600 is worn by a user.

[0068] The second detector 616 may have a third FOV and may be attached to the housing in a fixed position and orientation relative to the emitter 612 such that the third FOV at least partially overlaps the first FOV. The second detector 616 may be configured to measure a third intensity of light received within the third FOV, compute a third parameter associated with the measured third intensify, and provide a third signal comprising the third parameter to the controller 622.

[0069] In various embodiments, the headpiece 610 may comprise a motion sensor 618, e.g, a 6-axis accelerometer. The motion sensor 618 may provide a signal to the controller that may enable the controller to continuously determine the position of the headset in three-dimensional space and the direction in which the emitted light is pointed. In various embodiments, the controller may use the position of the headset and the direction in which the emitted light is pointed to determine whether the light is directed toward the projected area 320. In various embodiments, the controller may be configured to reduce the intensify when the light is not incident upon the projected area, e.g., to avoid blinding the other staff. In various embodiments, the controller may be configured to adjust the light intensify as the surgeon moves away from or closer to the projected area 320.

[0070] The user interface 624 may be in signal connection with the controller 622 and may be configured to accept selection of an intensify variable by a user action on a variable control, e.g., twisting a rotary7dial, and recognize identification of a setpoint by a user action, e.g., pressing a button. In various embodiments, the user interface 624 may comprise an actuator, e.g., a button or switch, that a user activates, e.g.. presses the button, to reset the intensify control function after a safety limit has been exceeded and the system has latched in a reduced-intensity state, e.g., the emitter 612 is off.

[0071] The controller 622 may also be electrically coupled to a power supply 626 that provides power to some or all of the components of the headpiece 610 and belt pack 620. In various embodiments, the power supply 626 comprises a battery.

[0072] In various embodiments, the headpiece 610 may comprise a motion sensor 618 that may be fixedly attached to the housing (not shown in Fig. 6) of the headpiece 610. The motionsensor 618 may be configured to measure acceleration associated with one or more of 6 degrees-of- freedom (DOF), i.e., linear acceleration along 3 perpendicular axes and angular acceleration about the same 3 axes. In various embodiments, a baseline position / orientation may be defined when the illumination setpoint is created, as discussed with respect to step 716 of Fig. 7. In various embodiments, a displacement of the housing from the baseline position and / or a rotation of the housing from the baseline orientation may be computed, by integration of the sensed acceleration, by the controller 622 based on measurements reported by the motion sensor 618. The function of the motion sensor 618 is further discussed with respect to step 720 of Fig. 7.

[0073] In various embodiments, a function of a device of Fig. 6 may be provided by a different device, e.g., a portion of the function of the example controller 622 may be provided by circuitry that is part of the emitter 612.

[0074] Fig. 7 depicts a flowchart 700 of an exemplar}' method of controlling a lamp, in accordance with various embodiments. The process may start with turning the power on for the lamp in step 710. The user may direct the light emitted by the emitter toward a target surface at a nominal working distance from the target surface in step 712. The user may manually adjust the intensity of the emitted light, e.g., using the user interface 624 of Fig. 6, to a desired level of illumination of the target surface in step 714. Once the lamp is providing the desired level of illumination, the user may create a setpoint by activating an actuator, e.g.. by pressing a button of the user interface 624 or speaking a voice command, in step 716. The lamp is now configured for the activity, e.g, a surgical procedure.

[0075] In various embodiments, steps 714-716 are not performed because the setpoint is predetermined, e.g., the setpoint is selected at the factory in a calibration process. In various embodiments, the predetermined setpoint may be selected to provide illumination within a desired range when the lamp is at a selected distance from a surface being illuminated.

[0076] In various embodiments, step 716 is not performed because the setpoint is determined by the last intensify selected in step 714, e.g, the current setting of the user interface 624.

[0077] During the activity, the illumination of the target area may be periodically measured at step 720, e.g., by a first detector 230, to generate a signal. The signal may be compared to the setpoint in step 730, which branches to step 732 if the signal is greater than the setpoint, i. e. , the illumination is too high, otherwise the process may pass to step 740. Step 732 decreases the intensify of the emitted light and may return to step 720. If the signal is less than thesetpoint, i.e., the illumination is too low, the process branches to step 742, otherwise the process passes to step 744. Step 742 increases the intensity of the emitted light and may return to step 720. If the current illumination is within an acceptable range, the process reaches step 744 and retains the current intensity of the emitted light and may return to step 720. In various embodiments, the process may cease at any step within the process upon the end of the activity, e.g., the surgical procedure has ended and a user has turned off the lamp.

[0078] In various embodiments, for example an IR detector configured to detect a contaminant on the face shield, only a portion of the steps of flowchart 700 are executed. In various embodiments, the temperature setpoint is previously defined and the operational procedure may jump from turning on power in step 710 to measuring the intensity in step 720. The intensity of the IR energy 542 radiated from the contaminant and face shield may be compared to the temperature setpoint in step 730, branching to step 732 if the measured intensity exceeds the setpoint. In step 732, the intensity of the emitted beam is reduced, e.g, reduced to a predetermined low level or the emitter is turned off, in order to avoid heating the contaminant to a temperature that may damage the face shield. In various embodiments, the controller "latches" the emitted light intensity at the reduced level until the user manually releases the latch, e.g., using the user interface 624, in order to provide time to remove the contaminant from the face shield. In certain embodiments, the controller '‘latches” the emitted light intensity at the reduced level until a predetermined duration of time has passed, e.g., a safety' timer, whereupon the process resumes at step 720. In various embodiments, the process may cease at any step within the process upon the end of the activity, e.g, the surgical procedure has ended and a user has turned off the lamp.

[0079] When the measured intensity is at or below the temperature setpoint at step 730, the process may branch from step 730 directly to step 720, i.e.. steps 740-744 may not be executed.

[0080] In various embodiments wherein a first detector is sensing the visible light illumination of the target surface and a second detector is sensing the IR radiation from the face shield, the controller accepts signals from both optical assemblies and controls the intensity of the projected light to maintain both measured intensities below their respective setpoints. In various embodiments, the controller may latch a reduced intensity after the temperature setpoint is exceeded by the signal from the second detector regardless of the signal from the first detector.

[0081] Application of such a lamp is not limited to a surgical environment and various embodiments provide the same feedback-control of the intensity of the projected light in other environments, for example a person working on a printed circuit board assembly (PCBA) on a workbench where a constant level of increased illumination improves the visibility of the features of the PCBA.

[0082] In various embodiments, the time-rate of increase or decrease of the intensity of the emitted light in steps 732 or 742 may be limited to a defined change / time to provide a smooth transition in illumination levels. In various embodiments, the measurement, comparison, and adjustment of steps 720, 730-732, 740-744 are essentially made continuously, e.g., steps 720, 730-732, and 740-744 repeat during operation of a lamp.

[0083] In various embodiments, the setpoint may comprise a range of acceptable intensity within which no change is made in the intensity of the emitter, i. e. , a “deadband. ” The perceived amount of change in brightness is proportional to the square root of the measured change in intensity of the light. For example, a 10% reduction in measured intensity is perceived as only a 5% change in brightness. It may be preferable to the user that the intensity of the projected light remain constant over a small range, e.g., a 10% change in perceived brightness, rather than the intensity constantly changing.

[0084] In various embodiments that comprise the motion sensor 618 of Fig. 6, step 720 may comprise measurement of the displacement in three-dimensional space and the 3-axis rotation of the headpiece, and therefore the direction of pointing axis 424 of the emitter 420 of Fig. 4, at the time of creating the setpoint. In various embodiments, the pointing axis 424 of the emitter 420 may be pointed at the area of interest, e.g., the surgical site, when the setpoint is created. Given a nominal distance from the headpiece to the target area, e.g., provided through the user interface 624, the relative position of the desired projected area can be calculated by the controller 622. In various embodiments, step 720 comprises a comparison of the measured position / orientation against the baseline position / orientation. In various embodiments, the intensity of the emitter 420 is not automatically adjusted while the emitter 420 is not pointed at the target area and / or at a distance from the target area that is different from the baseline by more than a defined tolerance. In various embodiments, the controller tracks the relative displacement and rotation of the headlamp from the baseline, calculates the FOV of the emitter relative to the area of interest, and enables automatic adjustment of the intensity of the emitter only when the FOV of the emitter includes the target area and / or is within a defined range of the distance of the emitter from the target area. In various embodiments where the nominaldistance is known, step 720 may include determining whether the pointing axis 424 intersects the desired target area; e.g. the projected area 426 coincides with the surgical site. If the pointing axis 424 intersects the desired target area, the process may proceed to step 730. In various embodiments, if the pointing axis 424 does not intersect with the desired target area, step 720 may maintain the emitted intensity at the last level. In various embodiments, if the pointing axis 424 does not intersect with the desired target area, step 720 may adjust the emitted intensity to a predetermined level, e.g., reducing the emitted intensity to a level that will not bother other proximate staff. In various embodiments, step 720 may return the emitted intensity to the last adjusted level when the pointing axis 424 again intersects with the desired target area.

[0085] Fig. 8 depicts an exemplary feedback control system 800 for controlling a lamp, in accordance with various embodiments. A setpoint 810 may be provided as a positive input to a comparator 820 while a signal from an optical sensor may be provided as a negative input. The comparator 820 may add the two signals and process them, e.g.. compare the difference between the two inputs to a deadband, and provide an output to the emitter 840. In various embodiments, this diagram is another representation of the steps 720, 730-732, and 740-744 of Fig. 7.

[0086] In summary, the disclosed apparatus describes a feedback-controlled lighting apparatus, e.g.. a surgical headlamp, that may provide, among other benefits, one or both of a constant illumination of an area of interest, e.g., a surgical site, and protection against overheating of objects, e.g., burning of tissue splattered on the face shield or singeing the gown of a nearby staff member when the surgeon looks that that staff member.Example Embodiments

[0087] Al. A lighting apparatus, comprising: a housing; an emitter fixedly attached to the housing, the emitter configured to: emit light at an adjustable first intensity; receive a first signal comprising a first parameter; and adjust the first intensity based in part on the first parameter; a first detector fixedly attached to the housing, the first detector configured to: measure a second parameter associated with the emitted light; and provide a second signal comprising the second parameter; and a controller having a first signal connection to the emitter and a second signal connection to the first detector, the controller configured to: receive the second signal from the first detector; compute a value of the first parameter based in part on a comparison of the second parameter to a setpoint; and provide the first signal to the emitter.

[0088] A2. The lighting apparatus of Al, wherein the second parameter comprises at least one of: a distance from the emitter to a first projected area illuminated by the emitted light; and a second intensity of light received by the first detector.

[0089] A3. The lighting apparatus of A2, wherein: the emitter emits light in a first field-of-view (FOV) that includes the first projected area; and the first detector receives light from a second FOV that overlaps the first FOV such that the second FOV includes a portion of the first projected area.

[0090] A4. The lighting apparatus of Al, further comprising: a second detector fixedly attached to the housing and comprising a third signal connection with the controller, the second detector configured to: measure a third intensity of light; compute a third parameter associated with the measured third intensity; and provide a third signal comprising the third parameter; wherein: the controller is further configured to receive the third signal from the second detector; and computation of the value of the first parameter is also based in part on a comparison of the third parameter to a second threshold.

[0091] A5. The lighting apparatus of A4, wherein: the emitter emits light in a first field-of-view (FOV) that includes a first projected area; the first detector receives light from a second FOV that overlaps the first FOV such that the second FOV includes a portion of the first projected area; the second detector receives light from a third FOV that includes at least one of: a portion of the first projected area; and a portion of a second projected area illuminated by the first FOV on a face shield being worn by a user who is also wearing the lighting apparatus.

[0092] A6. The lighting apparatus of A4, wherein: the first detector is configured to measure a second intensity of light only within a portion of a first band of light selected from a spectral group consisting of a visible band of light and an infrared (IR) band of light; and the second detector is configured to measure the third intensity of light only within a portion of a second band of light selected from the spectral group and different from the first band of light.

[0093] A7. The lighting apparatus of A4, wherein the controller is further configured to execute, if the second parameter is greater than a first safety threshold or the third parameter is greater than a second safety threshold, a safety action selected from a safety group consisting of: set the first parameter to a first safety value that will cause the emitter to reduce the first intensity to a predetermined safe level; turn off power to the emitter; and close a shutter that is disposed in the first FOV.

[0094] A8. The lighting apparatus of A7, wherein the controller is further configured to latch the first parameter, when a safety value is selected for the first parameter, such that the selected safety action is continued until either the controller receives a reset input or a safety timer that started when the selected safety action was executed times out.

[0095] A9. The lighting apparatus of Al, wherein the controller is further configured to execute, if the second parameter is greater than a first safety threshold, a safety action selected from a safety group consisting of: set the first parameter to a first safety value that will cause the emitter to reduce the first intensity to a predetermined safe level; turn off power to the emitter; and close a shutter that is disposed in a first field-of-view (FOV).

[0096] A10. The lighting apparatus of A9. wherein the controller is further configured to latch the first parameter, when a safety value is selected for the first parameter, such that the selected safety action is continued until either the controller receives a reset input or a safety timer that started when the selected safety action was executed times out.

[0097] All. The lighting apparatus of Al, wherein the housing is configured to be attached to an item of headgear configured to be worn by a user.

[0098] Al 2. The lighting apparatus of Al, further comprising: a user interface in signal connection with the controller and configured to provide a fourth signal comprising at least one of: a first input associated with the first intensity when a new setting of a variable control is selected by a user; and a second input associated with the setpoint when the user activates an actuator; and wherein the controller is further configured to: receive the fourth signal from the user interface; and adjust, upon receipt of the first input, at least one of the first parameter and the setpoint based in part on the first input.

[0099] Al 3. The lighting apparatus of A 12, wherein the controller is further configured to adjust, upon receipt of the second input, the setpoint to match a current value of the second parameter.

[0100] B14. The lighting apparatus of Bl, wherein the controller is further configured to: compare the second parameter to a first safety threshold; and execute, if the second parameter is greater than the first safety threshold, a safety action selected from a safety group consisting of: set the first parameter to a first safety value that will cause the emitter to reduce the first intensity to a predetermined safe level; turn off power to the emitter; and close a shutter that is disposed in the first FOV.

[0101] B15. The lighting apparatus of Al, further comprising: a motion sensor fixedly attached to the housing and in signal connection with the controller, the motion sensor configured to: measure at least one of a linear acceleration and an angular acceleration of the housing; compute a motion parameter associated with the measured at least one of the linear acceleration and the angular acceleration; and provide a motion signal comprising the motion parameter; wherein the controller is further configured to: receive the motion signal; compute, upon receipt of the second input, at least one of a baseline position and a baseline orientation of the housing; calculate, after receipt of the second input, at least one of a displacement of the housing from the baseline position and a rotation of the housing from the baseline orientation based in part on the received motion parameter; compare at least one of the displacement and the rotation to a second threshold and a third threshold, respectively; and maintain, when the at least one of the displacement and the rotation exceed the respective second and third thresholds, the first parameter as last computed while the at least one of the displacement and the rotation did not exceed the respective second and third thresholds.

[0102] C15. A method, comprising steps: emitting light, by an emitter, at an adjustable first intensity; adjusting the first intensity based in part on a first parameter; measuring a second parameter associated with the emitted light; and computing the first parameter based in part on a comparison of the second parameter to a setpoint.

[0103] Cl 6. The method of Cl 5. wherein: the light is emitted over a first field-of-view (FOV); and the second parameter comprises at least one of (a) a distance from the emitter to a first proj ected area illuminated by the emitted light and (b) a second intensity7of light received within a second FOV that partially overlaps the first FOV.

[0104] C17. The method of C16, further comprising steps: measuring athird intensity of light received within a third FOV that includes at least one of (a) a portion of the first projected area, and (b) a portion of a second projected area illuminated by the first FOV on a face shield being worn by a user who is also wearing the emitter; computing a third parameter associated with the measured third intensity; and adjusting the first parameter based in part on one or more of (a) a comparison of the second parameter to the setpoint, and (b) a comparison of the third parameter to a threshold.

[0105] C18. The method of C17, further comprising steps: comparing at least one of the second parameter and the third parameter to a respective first safety threshold and a second safety threshold; and executing, if the second parameter is greater than the first safety thresholdor the third parameter is greater than the second safety threshold, a safety action selected from a safety group consisting of (a) setting the first parameter to a first safety value that will cause the emitter to reduce the first intensity' to a predetermined safe level, (b) turning off power to the emitter, (c) closing a shutter that is disposed in the first FOV.

[0106] C19. The method of C17, wherein: the second intensity of light is measured only within a portion of a first band of light selected from a spectral group consisting of a visible band of light and an infrared (IR) band of light; and the third intensity of light is measured only within a portion of a second band of light selected from the spectral group and different from the first band of light.

[0107] Headings and subheadings, if any, are used for convenience only and do not limit the invention.

[0108] Reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” Use of the articles “a” and “an” is to be interpreted as equivalent to the phrase “at least one.” Unless specifically stated otherwise, the terms "a set" and “some” refer to one or more.

[0109] Terms such as “top,” “bottom,” “upper,” “lower,” “left,” “right,” “front,” “rear” and the like as used in this disclosure should be understood as referring to an arbitrary frame of reference, rather than to the ordinary gravitational frame of reference. Thus, a top surface, a bottom surface, a front surface, and a rear surface may extend upwardly, downwardly, diagonally, or horizontally in a gravitational frame of reference without limiting their orientation in other frames of reference.

[0110] Although the relationships among various components are described herein and / or are illustrated as being orthogonal or perpendicular, those components can be arranged in other configurations in some embodiments. For example, the angles formed between the referenced components can be greater or less than 90 degrees in some embodiments.

[0111] Although various components are illustrated as being flat and / or straight, those components can have other configurations, such as curved or tapered for example, in some embodiments.

[0112] Pronouns in the masculine (e.g., his) include the feminine and neuter gender (e.g., her and its) and vice versa. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended tobe encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. §112, sixth paragraph, unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “operation for.”

[0113] A phrase such as an “aspect” does not imply that such aspect is essential to the subject technology or that such aspect applies to all configurations of the subject technology. A disclosure relating to an aspect may apply to all configurations, or one or more configurations. A phrase such as an aspect may refer to one or more aspects and vice versa. A phrase such as an “embodiment” does not imply that such embodiment is essential to the subject technology or that such embodiment applies to all configurations of the subject technology. A disclosure relating to an embodiment may apply to all embodiments, or one or more embodiments. A phrase such as an embodiment may refer to one or more embodiments and vice versa.

[0114] The word “exemplary” is used herein to mean “serving as an example or illustration.” Any aspect or design described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects or designs.

[0115] All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. §112, sixth paragraph, unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for.” Furthermore, to the extent that the term “include,” “have,” or the like is used in the description or the claims, such term is intended to be inclusive in a manner similar to the term “comprise” as “comprise” is interpreted when employed as a transitional w ord in a claim.

[0116] Although embodiments of the present disclosure have been described and illustrated in detail, it is to be clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the scope of the present invention being limited only by the terms of the appended claims.

Claims

CLAIMSWhat is claimed is:

1. A lighting apparatus, comprising:a housing;an emitter fixedly attached to the housing, the emitter configured to:emit light at an adjustable first intensity;receive a first signal comprising a first parameter; andadjust the first intensity' based in part on the first parameter;a first detector fixedly attached to the housing, the first detector configured to: measure a second parameter associated with the emitted light; and provide a second signal comprising the second parameter; and a controller having a first signal connection to the emitter and a second signal connection to the first detector, the controller configured to:receive the second signal from the first detector;compute a value of the first parameter based in part on a comparison of the second parameter to a setpoint; andprovide the first signal to the emitter.

2. The lighting apparatus of claim 1, wherein the second parameter comprises at least one of:a distance from the emitter to a first projected area illuminated by the emitted light;anda second intensity of light received by the first detector.

3. The lighting apparatus of claim 2, wherein:the emitter emits light in a first field-of-view (FOV) that includes the first projected area; andthe first detector receives light from a second FOV that overlaps the first FOV such that the second FOV includes a portion of the first projected area.

4. The lighting apparatus of claim 1, further comprising:a second detector fixedly attached to the housing and comprising a third signal connection with the controller, the second detector configured to:measure a third intensity of light;compute a third parameter associated w ith the measured third intensity; and provide a third signal comprising the third parameter;wherein:the controller is further configured to receive the third signal from the second detector; andcomputation of the value of the first parameter is also based in part on a comparison of the third parameter to a first threshold.

5. The lighting apparatus of claim 4, wherein:the emitter emits light in a first field-of-view (FOV) that includes a first projected area;the first detector receives light from a second FOV that overlaps the first FOV such that the second FOV includes a portion of the first projected area;the second detector receives light from a third FOV that includes at least one of: a portion of the first projected area; anda portion of a second projected area illuminated by the first FOV on a face shield being worn by a user who is also wearing the lighting apparatus.

6. The lighting apparatus of claim 4, wherein:the first detector is configured to measure a second intensity' of light only within a portion of a first band of light selected from a spectral group consisting of a visible band of light and an infrared (IR) band of light; andthe second detector is configured to measure the third intensity of light only within a portion of a second band of light selected from the spectral group and different from the first band of light.

7. The lighting apparatus of claim 4, wherein the controller is further configured to execute, if the second parameter is greater than a first safety threshold or the third parameter is greater than a second safety threshold, a safety action selected from a safety group consisting of:set the first parameter to a first safety value that will cause the emitter to reduce the first intensity to a predetermined safe level;turn off power to the emitter; andclose a shutter that is disposed in a first field-of-view (FOV).

8. The lighting apparatus of claim 7, wherein the controller is further configured to latch the first parameter, when a safety value is selected for the first parameter, such that the selected safety action is continued until either the controller receives a reset input or a safety timer that started when the selected safety action was executed times out.

9. The lighting apparatus of claim 1, wherein the controller is further configured to execute, if the second parameter is greater than a first safety threshold, a safety action selected from a safety group consisting of:set the first parameter to a first safety value that will cause the emitter to reduce the first intensity to a predetermined safe level;turn off power to the emitter: andclose a shutter that is disposed in a first field-of-view (FOV).

10. The lighting apparatus of claim 9, wherein the controller is further configured to latch the first parameter, when a safety value is selected for the first parameter, such that the selected safety action is continued until either the controller receives a reset input or a safety timer that started when the selected safety action was executed times out.

11. The lighting apparatus of claim 1, wherein the housing is configured to be attached to an item of headgear configured to be worn by a user.

12. The lighting apparatus of claim 1, further comprising:a user interface in signal connection with the controller and configured to provide a fourth signal comprising at least one of:a first input associated with the first intensity when a new setting of a variable control is selected by a user; anda second input associated with the setpoint when the user activates an actuator;andwherein the controller is further configured to:receive the fourth signal from the user interface; andadjust, upon receipt of the first input, at least one of the first parameter and the setpoint based in part on the first input.

13. The lighting apparatus of claim 12, wherein the controller is further configured to adjust, upon receipt of the second input, the setpoint to match a current value of the second parameter.

14. The lighting apparatus of claim 1, wherein the controller is further configured to: compare the second parameter to a first safety threshold; andexecute, if the second parameter is greater than the first safety threshold, a safety action selected from a safety group consisting of:set the first parameter to a first safety value that will cause the emitter to reduce the first intensity to a predetermined safe level;turn off power to the emitter; andclose a shutter that is disposed in the first FOV.

15. A method, comprising the steps of:emitting light, by an emitter, at an adjustable first intensity;adjusting the first intensity based in part on a first parameter;measuring a second parameter associated with the emitted light; andcomputing the first parameter based in part on a comparison of the second parameter to a setpoint.

16. The method of claim 15, wherein:the light is emitted over a first field-of-view (FOV); andthe second parameter comprises at least one of (a) a distance from the emitter to a first projected area illuminated by the emitted light and (b) a second intensity of light received within a second FOV that partially overlaps the first FOV.

17. The method of claim 16, further comprising steps:measuring a third intensity of light received within a third FOV that includes at least one of (a) a portion of the first projected area, and (b) a portion of a second projected area illuminated by the first FOV on a face shield being worn by a user who is also wearing the emitter;computing a third parameter associated with the measured third intensity; and adjusting the first parameter based in part on one or more of (a) a comparison of the second parameter to the setpoint, and (b) a comparison of the third parameter to a threshold.

18. The method of claim 17, further comprising steps:comparing at least one of the second parameter and the third parameter to a respective first safety' threshold and a second safety threshold; andexecuting, if the second parameter is greater than the first safety threshold or the third parameter is greater than the second safety threshold, a safety action selected from a safety group consisting of (a) setting the first parameter to a first safety value that will cause the emitter to reduce the first intensity to a predetermined safe level, (b) turning off power to the emitter, (c) closing a shutter that is disposed in the first FOV.

19. The method of claim 17, wherein:the second intensity7of light is measured only w ithin a portion of a first band of light selected from a spectral group consisting of a visible band of light and an infrared (IR) band of light; andthe third intensity of light is measured only within a portion of a second band of light selected from the spectral group and different from the first band of light.

20. A method, comprising the steps of:emitting light, by an emitter, at an adjustable first intensity;turning the emitter off for a time period;measuring, by a detector, a background light intensity during the time period; adjusting the first intensity to a second intensity based at least in part on the background light intensity;turning the emitter on, thereby' emitting light at the second intensity7.

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