Lighting system for producing artificial sunlight

Abstract

A lighting system creates the perception of outdoor, clear sky sunlight in an indoor space without natural sunlight. The lighting system can be installed safely and reliably in indoor spaces having a wide range of sizes and layouts. For example, the lighting system may be configured for mounting or hanging from a ceiling, wall mounting, or as a floor supported device.

Description

LIGHTING SYSTEM FOR PRODUCING ARTIFICIAL SUNLIGHTCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The application claims the benefit of U.S. Provisional Application No. 63 / 601,190 filed on November 20, 2023 and U.S. Provisional Application No. 63 / 614,029 filed on December 22, 2023, each of which are incorporated by reference herein.BACKGROUNDTECHNICAL FIELD

[0002] The disclosed embodiments relate to a lighting system for producing artificial sunlight.DESCRIPTION OF RELATED ART

[0003] Natural sunlight is beneficial for many human biological and psychological functions, such as circadian rhythm regulation, mood enhancement, and overall well-being. However, access to natural sunlight is often limited, particularly in indoor environments. Some lighting systems exist in the form of artificial skylight boxes that are intended to artificially simulate characteristics of natural sunlight. However, existing systems pose many practical challenges due to their size, weight, and requirements for constructing drop ceilings to match the significant depth of the skylight boxes.SUMMARY

[0004] A lighting system generates artificial sunlight. An embodiment of the lighting system includes a light emitter to emit light, supporting electronics to electronically control the light emitter, and a diffuse reflective panel. The diffuse reflective panel includes at least a backing surface, a reflective surface opposite the backing surface, and a scattering substrate layered on the reflective surface. The reflective surface reflects the light from the light emitter through the scattering substrate. The scattering substrate scatters the light according to a scattering effect to produce reflected scattered light.

[0005] In an embodiment, the lighting system further comprises a structural bar coupled to the diffuse reflective panel and to the light emitter to structurally support the light emitter at aposition and orientation relative to the diffuse reflective panel such that the light from light emitter reflects off the reflective surface of the panel through the scattering substrate.

[0006] In an embodiment, the lighting system includes a ceiling attachment mechanism configured to attach the diffuse reflective panel to a ceiling with the backing surface closest to the ceiling. In this embodiment, the structural bar is structured to extend from the diffuse reflective panel away from the ceiling and to position and orient the light emitter to emit the light back towards the reflective surface.

[0007] In another embodiment, the lighting system includes a wall attachment mechanism configured to attach the panel to a wall with the backing surface closest to the wall. In this embodiment, the structural bar is structured to extend from the diffuse reflective panel away from the wall and to position and orient the light emitter to emit the light back towards the reflective surface.

[0008] In a further embodiment, the lighting system includes a floor stand to rest on a floor. In this embodiment, the structural bar extends vertically from the floor stand and supports the diffuse reflective panel at an opposite end of the structural bar from the floor stand. The light emitter is coupled to the structural bar at an attachment point between the floor stand and the diffuse reflective panel and is positioned and oriented to emit the light towards the reflective surface.

[0009] In another embodiment, the light emitter and the diffuse reflective panel are physically decoupled.

[0010] In an embodiment, the light emitter of the lighting system may comprise a lens positioned closer to a light source of the light emitter than a focal length of the lens, such that the lens defocuses the light from the light emitter.

[0011] In an embodiment, the scattering substrate causes a Rayleigh scattering effect of the light that mimics an atmospheric scattering effect of sunlight.

[0012] In an embodiment, the reflective surface and the scattering substrate are structured such that reflected light appears as a white spot where a center ray from the light emitter intersects the reflective surface and where the scattering substrate produces a predominately blue field of scattered light.

[0013] In an embodiment, the scattering substrate comprises an optically transparent material with suspended scattering particles.

[0014] In an embodiment, the lighting system further comprises a cooling sub-system to provide cooling to the light emitter. The cooling sub-system may comprise a coolant heat exchanger block to exchange heat between the light emitter and a coolant, a radiator to radiate heatabsorbed by the coolant, a fan to circulate air to the radiator to dissipate the heat, a coolant conduit to transport the coolant between the coolant heat exchange block and the radiator, a coolant pump to circulate the coolant through the coolant conduit, and a coolant reservoir coupled to the coolant conduit to store the coolant.

[0015] In an embodiment, at least a portion of the coolant conduit is supported by a structural bar that is coupled to the diffuse reflective panel and to the light emitter to structurally support the light emitter at a position and orientation relative to the diffuse reflective panel such that the light from light emitter reflects off the reflective surface of the panel through the scattering substrate.

[0016] In an embodiment, the supporting electronics include one or more temperature sensors to sense a temperature of a coolant of the cooling sub-system, and a fan controller to control a speed of the fan based on the temperature.

[0017] In an embodiment, the lighting system includes a motion sub-system configured to create motion of the lighting system while maintaining alignment between the light emitter and the diffuse reflective panel. In an embodiment, the motion sub-system is configured to create relative motion of the light emitter relative to the panel that changes a position of a center ray of the light emitter on the reflective surface. In another embodiment, the motion sub-system is configured to create the relative motion in a manner that simulates movement of the sun throughout a day.

[0018] In another embodiment, a lighting array generates artificial sunlight. The lighting array includes a plurality of light emitters to emit respective light beams and a plurality of diffuse reflective panels. Each of the diffuse reflective panels include at least a backing surface, a reflective surface opposite the backing surface, and a scattering substrate layered on the reflective surface. The reflective surface reflects light from one or more of the light emitter through the scattering substrate. The scattering substrate scatters the light with a scattering effect to produce reflected scattered light. A control device electronically controls the plurality of light emitters.

[0019] In an embodiment, the control device controls the plurality of light emitters to operate in a coordinated lighting pattern.

[0020] In another embodiment, a lighting system for generating artificial sunlight comprises a light emitting means for emitting light, control means for controlling the light emitting means, and diffuse for diffusively reflecting the light. The diffuse reflecting means includes scattering means for scattering reflected light according to a scattering effect to produce reflected scattered light, reflecting means for reflecting the light from the light emitting means through thescattering means, and supporting means for structurally supporting the scattering means and the reflecting means.BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG. 1 A illustrates a zoomed-out view of a ceiling-mounted embodiment of a lighting system.

[0022] FIG. IB illustrates a zoomed-in side view of the ceiling-mounted embodiment of the lighting system.

[0023] FIG. 1C illustrates a perspective view of the ceiling-mounted embodiment of the lighting system.

[0024] FIG. 2 illustrates an example embodiment of a diffuse reflective panel for a lighting system.

[0025] FIG. 3 illustrates an example embodiment of supporting components for a lighting system.

[0026] FIG. 4 illustrates an example embodiment of a light emitter assembly for a lighting system.

[0027] FIG. 5A illustrates a first view of a freestanding embodiment of a lighting system.

[0028] FIG. 5B illustrates a second view of a freestanding embodiment of a lighting system.

[0029] FIG. 6 illustrates a wall-mounted embodiment of a lighting system.

[0030] FIG. 7 illustrates a decoupled embodiment of a lighting system.

[0031] FIG. 8 illustrates an example embodiment of a lighting array.

[0032] FIG. 9 illustrates an example embodiment of a motion-controlled lighting system.

[0033] The figures depict various embodiments for purposes of illustration only. One skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles described herein.DETAILED DESCRIPTION

[0034] The Figures (FIGS.) and the following description describe certain embodiments by way of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles described herein. Reference will now be made to severalembodiments, examples of which are illustrated in the accompanying figures. Wherever practicable, similar or like reference numbers may be used in the figures and may indicate similar or like functionality.

[0035] A lighting system creates the perception of outdoor, clear sky sunlight in an indoor space without natural sunlight. The lighting system can be installed safely and reliably in indoor spaces having a wide range of sizes and layouts. For example, the lighting system may be configured for mounting or hanging from a ceiling, wall mounting, or as a floor supported device.

[0036] FIGs. 1A-1C illustrate a first embodiment of a lighting system 100. FIG. 1A shows the lighting system 100 as it may be placed within a room 102 and perceived by an observer 104. FIG. IB shows a zoomed-in cross-sectional view of the lighting system 100. FIG. 1C illustrates a perspective view of the lighting system 100.

[0037] The lighting system 100 includes a light emitter assembly 106 that outputs an emitted light beam 108, and a diffuse reflective panel 110 that reflects and diffuses the emitted light beam as reflected light 112. The lighting system 100 may furthermore comprise various supporting components 114 (e.g., electronics) described in further detail below.

[0038] The diffuse reflective panel 110 both reflects the emitted light beam 108 and diffuses the light based on a Rayleigh (or Rayleigh-like) scattering effect. The light emitter assembly 106 and diffuse reflective panel 110 may be designed such that reflected light 112 is of sufficient intensity (e.g., greater than 1,000 lux) and has electromagnetic radiation spectrum of sufficient color rendering index (CRI) (e.g., 90 or above) to substantially mimic the appearance of natural light from the perspective of the human observer 104 in a room 102. For example, in one embodiment, the lighting system 100 may produce light of approximately 8500 lux at eye level over an area of approximately 2.5 square meters. In other embodiments, the lighting system may produce light anywhere in the range of 5000-10000 lux at eye level over an area of 1-4 square meters. In further embodiments, the light system 100 may produce light in the range of 10000- 20000 lux over an area of 1-4 square meters.

[0039] The reflected light 112 may appear similar to sunlight filtered through the atmosphere on a clear day. From a position of the observer 104 in the room 102, the reflected light 112 appears as a predominately blue light field with an artificial sun 118 (e.g., a luminous white spot) at a position where a central path 122 of the emitted light beam 108 reflects off the diffuse reflective panel 110. In some embodiments, visibility of the artificial sun 118 may be dependent on the viewing angle of the observer. For example, the artificial sun 118 may appear when the observer 104 is at certain positions relative to the lighting system 100 and does not necessarily appearfrom other positions (e.g., due to diffusion of the reflected light 112). For example, a parallax effect of the diffuse reflective panel 110 may provide an illusion of depth that changes how the artificial sun 118 appears from different viewing angles.

[0040] FIGs. 1A-C illustrate a ceiling-attached embodiment of the lighting system 100 that is rigidly mounted or suspended from the ceiling of the room 102 (e.g., via a ceiling attachment mechanism 120. In this configuration, the diffuse reflective panel 110 is oriented to reflect light 112 substantially downward away from the ceiling within some range of possible orientation angles. For example, a central ray 122 of the reflected light 112 may point at an angle between - 90° to 90° from perpendicular to the floor. In this variation, the supporting components 114 may be mounted on a top surface of the diffuse reflective panel 110 such that they do not interfere with the emitted light beam 108 or the reflected light beam 112. The ceiling attachment mechanism 120 may comprise, for example, a cable attachment system, screws, bolts, or other attachment mechanism.

[0041] The light emitter assembly 106 is positioned and oriented to emit light 108 substantially upward towards the reflective surface of the diffuse reflective panel 110. In an embodiment, the light emitter assembly 106 is positioned at an appropriate distance from the diffuse reflective panel 110 and oriented such that its range of emission angles substantially covers the surface area of the diffuse reflective panel 110 with zero or minimal overspill of emitted light beyond the edges of the reflective surface of the diffuse reflective panel 110. Furthermore, the light emitter assembly 106 may operate to provide substantially consistent illumination across the panel 110.

[0042] In the illustrated embodiment, the light emitter assembly 106 is connected to the diffuse reflective panel 110 via a structural bar 116 that extends at a downward angle from an edge of the diffuse reflective panel 110 and bends inward towards a central axis through the diffuse reflective panel 110, with the light emitter assembly 106 positioned at a distal end of the structural bar 116 and oriented to emit the light beam 108 towards the diffuse reflective panel 110. In this configuration, the structural bar 116 is entirely or substantially outside the beam of emitted light 108 directed towards the diffuse reflective panel 110 (i.e., the structural bar 116 does not block the emitted beam 108), and only minimally blocks reflected light 112 from a limited range of observation angles.

[0043] FIG. 2 illustrates an example embodiment of a diffuse reflective panel 110. In this embodiment, the diffuse reflective panel 110 comprises a backing layer 202, a reflective layer 204 with a reflective surface (e.g., a mirror), and a scattering substrate 206.

[0044] The scattering substrate 206 may comprise a substantially optically transparent material in which scattering particles are suspended to produce a scattering effect of light reflectedthrough the substrate 206 (e.g., Rayleigh or Rayleigh-like scattering effect). The particles may be of specific size to produce the desired scattering and create the perception of a substantially blue light field that mimics the appearance of a blue sky resulting from sunlight being scattered by particles in the atmosphere. The optically transparent material of the scattering substrate 206 may comprise a material such silicate glass, Polymethyl methacrylate (often called acrylic or PMMA), or polycarbonate. The scattering particles may include varying concentrations of titanium dioxide nanoparticles in resin that are dispersed using an ultrasonic probe to prevent clumping. In an example embodiment, the particles may be less than 150 nanometers. In other embodiments, the particles may be in the range 50-200 nanometers. The scattering substrate 206 may be of different thicknesses depending on the specific design and the desired scattering effect. Furthermore, the scattering substrate 206 may include various material characteristics that affect the transmission, reflection, and scattering of incident light. For example, in some embodiments, there are relatively few scattering particles in the direct path of the reflected beam 112, such that a high proportion of photons pass through the scattering substrate directly, thus mimicking the appearance of an artificial sun 118 to an observe 104. The scattering substrate may be designed to create desired dimensions and intensity of the white spot (mimicking an artificial sun. For example, the scattering particles of the scattering substrate 206 may be distributed non-uniformly in a manner that shapes the desired size and appearance of the artificial sun.

[0045] In other embodiments, the density distribution of particles may be designed to avoid the appearance of the artificial sun 118. For example, the scattering substrate 206 may have a significantly higher proportion of scattering particles in the direct path of the reflected beam 112, such that the reflected light 112 is highly diffused and appearance of an artificial sun 118 is not apparent to the observer 104. For example, a higher concentration of scattering particles may be present in the region where the emitted light 108 directly reaches the reflective layer 204 than in peripheral regions of the scattering substrate 206.

[0046] The reflective layer 204 may include a thin film mirror deposited directly onto the scattering substrate 206. Alternatively, the reflective layer 204 can comprise an adhesive reflective sheet bonded to the scattering substrate 206.

[0047] The backing layer 202 may comprise any supportive material sufficient to structurally support the reflective layer 204 and / or other components that may be attached to the backing layer 202 as further described below. The backing layer 202 may comprise a protective material such as a polyvinyl chloride film. In other embodiments, a different similar material may be used that blocks transmittance of light passing through the reflective layer 204, is scratch resistant, flexible, and temperature stable. Alternatively, the backing layer 202 may comprise arigid metal.

[0048] FIG. 3 illustrates an example embodiment of supporting components 114 (e.g., electronics and cooling) for a lighting system 100. The supporting components 114 may include electronics such as one or more power supplies 312, a control board 308, and an electrical lead 322 for coupling to the light emitter assembly 106.

[0049] The power supply 312 may comprise one or more batteries and / or a power adapter for a power outlet. In some embodiments, the power supply 312 may comprise a low voltage power unit to provide low voltage power for powering the control board 308 and other supporting electronics, and a current driving unit to power the light emitter device 318 of the light emitter assembly 106 via the electrical lead 322. In an embodiment, the electrical lead 322 may run internally to the structural bar 116 or may be externally coupled to the structural bar 116.

[0050] The control board 308 may control power (e.g., voltage and / or current) to the light emitter assembly 106 to control the lighting effect. For example, the control board 308 may control the output intensity of the light emitter device 318, color of the light emitter assembly 106, or other lighting characteristics. In one implementation, the control board 308 includes a pulse width modulation (PWM) controller that employs PWM dimming to control brightness of each LED channel. The control board 308 may control dimming, color, or other parameters in response to an input from an integrated input device (e.g., button, switch, dial, etc.) or external remote control.

[0051] In some embodiments, the control board 308 may dynamically change the lighting intensity and / or color over time to achieve various lighting patterns or lighting effects. For example, in one embodiment, the control board 308 may control the light emitter device 318 to mimic natural lighting changes that occur throughout the day. In other embodiments, the control board 308 may control the light emitter device 318 to mimic different weather-based lighting conditions such as clear skies, partly cloudy skies, overcast skies, lightning storms, etc.

[0052] In further embodiments, the control board 308 can control color and / or brightness of the light emitter device 318 based on a detected ambient light brightness and / or color. For example, the control board 308 may operate to increase the brightness of ambient light by a fixed amount (e.g., 50%) or a user-configurable amount. In another example, the control board 308 can change the color of the light output in synchronization with detected light or visual features from a display device (e.g., a television) or in synchronization with audio features from music or other ambient audio. In another example, the control board 308 can change color of the light output based on biometric data or other data sensed by a connected wearable device such as a smartwatch, smart ring, fitness tracker, or other wearable device. For example, the control board308 may receive signals to adjust lighting conditions based on detecting heart rate variability (e.g., increase brightness with decreasing HRV). Alternatively, the control board 308 may receive signals indicating whether a person is asleep or awake and turn on the light emitter device 318 responsive to detecting that the person is awake. In yet another example, the control board 308 could change the lighting conditions based on detecting a user’s activities from a computer vision system, mobile application, audio processing system, or other smart detection system. For example, the control board 308 can change lighting conditions to make it whiter when a person is detected to be cooking and make it warmer when the person is detected to be reading. In further embodiments, color of the light emitter device 318 may be changed directly from a connected mobile application. Here, the application could learn patterns in the user’s change and predictively adjust the color and / or brightness of light in response.

[0053] The control board 308 may furthermore provide control functionality to cooling system components as further described below. The control board 308 may also support other system functions such as monitoring power input, monitoring battery life (where batteries are used in the power supply), and sensing various conditions (e.g., via sensors 306 discussed below).

[0054] In an embodiment, the control board 308 may include a wireless transmitter to enable wireless control of the lighting system 100. For example, the wireless transmitter may connect to a WiFi, Z-wave, Zigbee, Bluetooth, Bluetooth Low Energy (BLE), or other local area network that allows the control board 308 to send status information and receive control signals from an application accessed through a mobile device or other computing device. In further embodiments, the control board 308 may control output of various alerts indicating fault conditions, recommended maintenance, or other notifications to alert a user to various operating conditions of the lighting system.

[0055] The supporting components 114 may furthermore include various cooling components to maintain operational temperature of the light emitter device 318. Cooling components may include, for example, a heat exchanger 320, a radiator 314, a fan 316, a coolant conduit 310, a coolant pump 304, and a coolant reservoir 302. The coolant pump 304 pumps coolant (e.g., water or other fluid) through the coolant conduit 310 to enable the coolant to circulate between the heat exchanger 320 (adjacent to the LED Device 404) and the radiator 314. The heat exchanger 320 operates to absorb heat from the light emitter device 318 into the coolant. The coolant is pumped to the radiator 314 via the coolant conduit 310. The radiator 314 operates to radiate the heat absorbed by the coolant and is aided by one or more fans 316 that circulate air around the radiator 314. The coolant reservoir 302 stores coolant for circulation through the coolant conduit 310.

[0056] In an embodiment, the supporting components may include sensors 306 such as a temperature sensor to sense a temperature of the coolant or directly measure the LED temperature. A fan controller (which may be integrated with the control board 308) may then control a speed of the fan 316 based on the temperature. For example, the fan controller may turn on the fans 316 when the coolant or LED temperature reaches a threshold temperature and may turn off the fan 316 when the coolant or LED temperature drops below a threshold temperature. Alternatively, the fan controller may variably control the speed of the fan 316 dependent on the sensed temperature. The sensors 306 may furthermore include one or more flow rate sensors to sense a flow rate of the coolant. A pump controller (which may be integrated into the control board 308) may then control the coolant pump 304 based on the sensed flow rate. For example, the pump controller may turn the components of the lighting system 100 on or off depending on the sensed flow rate or may variably control the pump speed depending on the flow rate. The sensed flow rate may be utilized as a safety cut off to turn off the light emitter device 318 if the flow rate drops below a threshold (which may be indicative of a leak, blockage, air bubble, or pump failure). Alternatively, the light emitter device 318 may be dimmed (without necessarily turning off) in response to detecting a flow rate below a threshold value. In an example control scheme, the coolant pump 304 may be controlled to run at full power upon initial turn on to purge air bubbles prior to activating the light emitter device 318. Once the flow rate reaches a predefined value, the light emitter device 318 may be turned on. In another example, the pump controller may variably control the flow rate of the coolant pump 304 to enable higher or lower cooling performance to be dynamically adjusted.

[0057] The sensors 306 may furthermore include one or more thermal fuses in line with each color channel of the LED device 318 or one or more fuses in line with multiple channels of the LED device 318. These fuses may be rated slightly above the intended operating temperature of the LED device 318 such that they will blow if the temperature exceeds a threshold of the fuses, thereby cutting off power to the LED device 318.

[0058] FIG. 4 illustrates an example embodiment of a light emitter assembly 106. The light emitter assembly 106 includes at least one light emitting diode (LED) device 404, a circuit board 406, and the heat exchanger 320. The LED device 404 may comprise a chip-on-board (CoB) LED that includes a plurality of LEDs mounted on a thermally efficient substrate. Alternatively, other types of LED devices 404 may be used. In an embodiment, the LED device 404 may be configured to produce a sufficiently high luminous flux per unit area such that the observer experiences a luminous flux per unit area of at least 1,000 lux or higher in the reflected light. Depending on the desired effect (e.g., cloudy data or sunny day), the luminous flux per unit could be in the range of 1000 to 100,000 lux. The LED device 404 may be mounted on thecircuit board 406, which may provide structural support and additional supporting electronics. The circuit board 406 with mounted LED device 404 may be placed adjacent to the heat exchanger 320 to enable cooling of the LED device 404. In some implementations, thermal fuses (not shown) may positioned in between the LED device 404 and the heat exchanger 320. In some embodiments, the heat exchanger 320 may be mounted to the circuit board 406 on an opposite surface from the LED device 404. In alternative embodiments, different methods of cooling may be used. In yet further embodiments, LEDs or other lighting elements (e.g., halogen lamps or xenon arc lamps) may be used that do not necessarily require cooling. For example, in some embodiments, the LED elements may be spread over a larger physical area, which may allow the LEDs to remain operational in the absence of an active cooling system.

[0059] The lens 402 focuses the light beam 108 from the LED device 404 in a controlled manner. In an embodiment, the lens 402 may be positioned substantially nearer to the LED device 404 than the focal length of the lens 402. The light 108 emitted by the LED device 404 is refracted in the lens 402 and directed towards the diffuse reflective panel 110 as the emitted light 108. The lens 402 and LED device 404 may be dimensioned, positioned, and orientated such that the emitted light 108 reaches the diffuse reflective panel 110 as a relatively sharp circle or ellipse, minimizing the overspill of light beyond the edges of the diffuse reflective panel 110. For example, as shown in FIGs. 1A-1C, the lens 402 may operate to refract the emitted light 108 such that the spatial distribution of the emitted light 108 substantially coincides with the reflective surface of the diffuse reflective panel 110. By positioning the lens 402 such that emitted light 108 is out of focus, the emitted light 108 naturally blurs the light pattern from the LED device 404, and thus avoids an image of the LED die pattern reflecting off the diffuse reflective panel 110. Thus, the lens 402 contributes to diffusion prior to the emitted light 108 being reflected. In some embodiments, the material properties of the scattering substrate 206 may be designed for increased scattering in the region where the emitted light 108 directly hits the reflective surface such that there is increased scattering in this area.

[0060] In an embodiment, various coatings may be applied to the lens 402 to minimize reflection of light at the interface between the lens 402 and the surrounding air. The shape of the lens 402 may also be adapted physically to control the shape of the emitted light 108.

[0061] The circuit board 406 may comprise a printed circuit board (PCB) layered over the LED device 404. The circuit board 406 may include pins or other connectors on the underside of the circuit board 406 to connect to power pads of the LED device 404. Connectors on the top of the circuit board 406 may include wiring terminals for wiring to power lines.

[0062] In an embodiment, the LED device 404 may comprise one or more bicolor LEDs thatenable a range of hue outputs depending on the relative outputs of each of the LED colors. In one such implementation, the LED device 404 includes alternating stripes of warm color and cool color diodes, operating in a range of, for example, 2600K to 7500K, effectively mimicking the full spectrum of natural light. Here, warm color diodes may include, for example, diodes that are primarily red, orange, or yellow and have color temperatures in the range of, for example, 800-3200K. Cool color diodes may include, for example, diodes that primarily emit violet, blue, or green light and may have color temperatures in the range of 4000-7500K. To enable a light output that is uniform in appearance, a glass diffuser (e.g., 600 grit) may be positioned between the LED device 404 and the lens 402 to blend the light from the bicolor LED.

[0063] In some embodiments where color of the lighting system 100 is controllable by the control board 308, the light emitter device 318 may comprise a multichannel chip-on-board LED having two or more hues of diodes that enable color tuning. For example, the device 318 may include iris shutters made of color fdtering plastic. In some embodiments, the iris shutters could be stacked to enable color mixing. Furthermore, the iris could be controlled to be partially closed to create gradient effects. In other embodiments, fdters could be alternated using a revolving fdtering mechanism about the light emitter device 318 (like a gatling gun). In further embodiments, color fdters could be alternated by spooling a conveyer belt of different fdters of the light emitter device 318. In further embodiments, the control board 308 could adjust the temperature of the COB to change the hue of the LEDs. For example, by causing an increase in temperature, the control board 308 may shift white light LEDs towards red. In an embodiment, the temperature may be controlled by adjusting temperature of the coolant by varying the pump speed, fan speed, and / or pulse-width-modulation (PWM) duty cycle of the LED driver to adjust hue of the LEDs.

[0064] FIGs. 5A-5B illustrates an example embodiment of a lighting system 100 in a freestanding form factor. In this embodiment, the supporting components 114 may be integrated into a floor stand unit 502 that rests on the ground. The structural bar 116 may be embodied as a post that extends from the floor stand unit 502 and supports the diffuse reflective panel 110 on at least one end. The light emitter assembly 106 may furthermore extend from an attachment point along the structural bar 116 and may be positioned and oriented such that the spatial distribution of the emitted light 108 substantially coincides with the surface area of the diffuse reflective panel 110.

[0065] FIG. 6 illustrates another example of a lighting system 100 that is configured for wall mounting, e.g., to simulate a window. The form factor of the lighting system 100 may be substantially the same as the ceiling mounted form factor described above. However, in this embodiment, the supporting components 114 may be integrated within a box structure on theback of the diffuse reflective panel 110 to provide a flat surface for contacting the wall. Alternatively, the supporting components 114 may be housed in a separate housing (e.g., resting on the floor) that may be connected via wires hidden in conduits or other structures. The lighting system 100 may include a wall attachment mechanism 602 for attaching to the wall (e.g., screws, bolts, cables, or other attachment mechanism).

[0066] FIG. 7 illustrates another embodiment of a lighting system 100 in which the light emitter assembly 106 and the diffuse reflective panel 110 may be structurally separate components. In this embodiment, the diffuse reflective panel 110 may comprise a standalone sheet without necessarily including any electronic supporting components 114 (not shown in FIG. 7). A separate light emitter assembly 106 may include integrated supporting components 114 (e.g., electronics and cooling) or these may be integrated into a separate housing. In an embodiment, the light emitter assembly 106 may include a panel to obstruct a line of sight between an observer 104 (in a typical position in the room) and the emitted light from the light emitter assembly 106. Alternatively, the light emitter assembly 106 may be strategically where there is no direct line of sight to the eyes of an observer 104 (for a typical position of the observer 104), such as in a position above eye level behind a shelf, cabinet.

[0067] FIG. 8 illustrates another embodiment of a lighting array 800 that includes an array of individual lighting systems 100 as described above. In some embodiments, a separate control device 802 (e.g., a mobile phone or dedicated controller) may jointly control the lighting systems 100 in a coordinated manner. For example, the control device 802 may turn the array of lighting systems 100 on or off at the same time and may control lighting intensity, color, or display patterns in a coordinated way. In further embodiments, the control device 802 may control each lighting system 100 differently in a coordinate way to achieve a desired effect. For example, the array 800 of lighting systems 100 may be jointly controlled to create a desired spatial lighting pattern which may also vary over time in a coordinated way. In other embodiments, the array 800 of individual lighting systems 100 may include all or partially shared supporting components 114. For example, a central control board may be coupled to the array of lighting systems 100 and provide central control. In other examples, the array 800 of lighting systems 100 may include a motion detector and may invoke various lighting patterns in response to detected motion. For example, the array 800 of lighting systems 100 may increase in brightness or turn on when an observer 104 is sensed underneath them. Furthermore, in an embodiment, the array 800 of lighting systems 100 may include a shared cooling loop in which a common coolant conduit 310 is coupled to cool the respective LED devices 404 in the array 800.

[0068] In yet further embodiments, a single lighting system 100 or an array 800 of lighting systems may generate motion of the diffuse reflective panel 110, the light emitter assembly 106or both. For example, as illustrated in FIG. 9, the lighting system 100 may include one more actuators 902 that are controlled to change position and / or orientation of the light emitter assembly 106 relative to the diffuse reflective panel 110, e.g., to simulate movement of the sun in the sky. For example, the structural arm 116 may be pivotable about a hinge point based on force applied by an actuator 902. The actuator 902 may be electronically controlled (e.g., via the control board 308). Alternatively, the lighting system 100 may be configured to enable passive motion (e.g., a pendulum action) using various suspension cables or other components.

[0069] The foregoing description of the embodiments has been presented for the purpose of illustration; it is not intended to be exhaustive or to limit the embodiments to the precise forms disclosed. Persons skilled in the relevant art can appreciate that many modifications and variations are possible in light of the above disclosure.

[0070] The language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope is not limited by this detailed description, but rather by any claims that issue on an application based hereon. Accordingly, the disclosure of the embodiments is intended to be illustrative, but not limiting, of the scope of the invention.

Claims

CLAIMS1. A lighting system for generating artificial sunlight, the lighting system comprising: a light emitter to emit light; supporting electronics to electronically control the light emitter; and a diffuse reflective panel including at least a backing surface, a reflective surface opposite the backing surface, and a scattering substrate layered on the reflective surface, the reflective surface for reflecting the light from the light emitter through the scattering substrate, and the scattering substrate to scatter the light according to a scattering effect to produce reflected scattered light.

2. The lighting system of claim 1, further comprising: a structural bar coupled to the diffuse reflective panel and to the light emitter to structurally support the light emitter at a position and orientation relative to the diffuse reflective panel such that the light from light emitter reflects off the reflective surface of the panel through the scattering substrate.

3. The lighting system of claim 2, further comprising: a ceiling attachment mechanism configured to attach the diffuse reflective panel to a ceiling with the backing surface closest to the ceiling; and wherein the structural bar is structured to extend from the diffuse reflective panel away from the ceiling and to position and orient the light emitter to emit the light back towards the reflective surface.

4. The lighting system of claim 2, further comprising: a wall attachment mechanism configured to attach the panel to a wall with the backing surface closest to the wall; and wherein the structural bar is structured to extend from the diffuse reflective panel away from the wall and to position and orient the light emitter to emit the light back towards the reflective surface.

5. The lighting system of claim 2, further comprising: a floor stand to rest on a floor; wherein the structural bar extends vertically from the floor stand and support the diffuse reflective panel at an opposite end of the structural bar from the floor stand; and wherein light emitter is coupled to the structural bar at an attachment point between the floor stand and the diffuse reflective panel and is positioned and oriented to emit the light towards the reflective surface.

6. The lighting system of claim 1, wherein the light emitter and the diffuse reflective panel are physically decoupled, and wherein the lighting system further comprises: a structural arm to support the light emitter at a position and orientation relative to the diffuse reflective panel such that the light from the light emitter reflects off the reflective surface of the diffuse reflective panel through the scattering substrate.

7. The lighting system of claim 1, wherein the light emitter comprises: a lens positioned closer to a light source of the light emitter than a focal length of the lens, such that the lens defocuses the light from the light emitter.

8. The lighting system of claim 1, wherein the scattering substrate causes a Rayleigh scattering effect of the light that mimics an atmospheric scattering effect of sunlight.

9. The lighting system of claim 1, wherein the reflective surface and the scattering substrate are structured such that reflected light appears as a white spot where a center ray from the light emitter intersects the reflective surface and where the scattering substrate produces a predominately blue field of scattered light.

10. The lighting system of claim 1, wherein the scattering substrate comprises an optically transparent material with suspended scattering particles.

11. The lighting system of claim 1, further comprising: a cooling sub-system to provide cooling to the light emitter.

12. The lighting system of claim 11, wherein the cooling sub-system comprises: a coolant heat exchanger block to exchange heat between the light emitter and a coolant; a radiator to radiate heat absorbed by the coolant; a fan to circulate air to the radiator to dissipate the heat; a coolant conduit to transport the coolant between the coolant heat exchange block and the radiator; a coolant pump to circulate the coolant through the coolant conduit; and a coolant reservoir coupled to the coolant conduit to store the coolant.

13. The lighting system of claim 12, wherein the cooling sub-system further comprises: one or more thermal fuses to cut power to the light emitter in response to temperature exceeding a temperature threshold.

14. The lighting system of claim 12, wherein at least a portion of the coolant conduit is supported by a structural bar that is coupled to the diffuse reflective panel and to the light emitter to structurally support the light emitter at a position and orientation relative to the diffusereflective panel such that the light from light emitter reflects off the reflective surface of the panel through the scattering substrate.

15. The lighting system of claim 12, wherein the supporting electronics include: one or more temperature sensors to sense a temperature of a coolant of the cooling subsystem; and a fan controller to control a speed of the fan based on the temperature.

16. The lighting system of claim 1, further comprising: a motion sub-system configured to create motion of the lighting system while maintaining alignment between the light emitter and the diffuse reflective panel.

17. The lighting system of claim 1, further comprising: a motion sub-system configured to create relative motion of the light emitter relative to the panel that changes a position of a center ray of the light emitter on the reflective surface.

18. The lighting system of claim 17, wherein the motion sub-system is configured to create the relative motion in a manner that simulates movement of the sun throughout a day.

19. The lighting system of claim 1, wherein the light emitter comprises a combination of warm color and cool color diodes.

20. The lighting system of claim 19, wherein the light emitter further comprises a diffuser to blend light from the warm color and cool color diodes.

21. The lighting system of claim 1, wherein the supporting electronics include a pulse width modulation dimmer controller to control dimming of the light emitter.

22. A lighting array for generating artificial sunlight, the lighting array comprising: a plurality of light emitters to emit respective light beams; a plurality of diffuse reflective panels, wherein each of the diffuse reflective panels include at least a backing surface, a reflective surface opposite the backing surface, and a scattering substrate layered on the reflective surface, the reflective surface for reflecting light from one or more of the light emitter through the scattering substrate, and the scattering substrate to scatter the light with a scattering effect to produce reflected scattered light; and a control device to electronically control the plurality of light emitters.

23. The lighting array of claim 22, wherein the control device controls the plurality of light emitters to operate in a coordinated lighting pattern.

4. A lighting system for generating artificial sunlight, the lighting system comprising: a light emitting means for emitting light; control means for controlling the light emitting means; and diffuse reflecting means for diffusively reflecting the light, the diffuse reflecting means including at least: scattering means for scattering reflected light according to a scattering effect to produce reflected scattered light; reflecting means for reflecting the light from the light emitting means through the scattering means; and supporting means for structurally supporting the scattering means and the reflecting means.

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