FI20207120A1

FI20207120A1 - A lighting system and luminaire for simulating sunny sky scenes

Info

Publication number: FI20207120A1
Application number: FI20207120A
Authority: FI
Inventors: Wei Li
Original assignee: Wei Li
Priority date: 2019-11-05
Filing date: 2019-11-05
Publication date: 2021-05-06
Also published as: DE202020106342U1

Abstract

Toimitukseen sisältyy optinen elementti, valaistusjärjestelmä ja LED-valaisin. Säädettävän valkoisen valon lähteen edessä käytettävä optinen elementti on konfiguroitu luomaan suhteellisen tasainen luonnollista auringonvaloa vastaava spektri. Valaistusjärjestelmän muodostavat optinen elementti, säädettävä valkoisen valon lähde ja värisäädettävä valopaneeli. Valkoisen valon lähteen värilämpötila on valittavissa 2400 ja 6500 kelvinin välillä. Värisäädettävä valopaneeli mahdollistaa erilaisten luonnollisten valaistusolosuhteiden luomisen. Valopaneeli koostuu valojohteeksi muotoillusta diffuusoripaneelista. Sen RGB, RGBA tai RGBW -LEDien avulla voidaan luoda haluttu väri, intensiteetti ja kuvio. Erilaisia valaistusolosuhteita simuloiva LED-valaisin helpottaa vuorokausirytmin noudattamista terveyttä ja hyvinvointia parantaen. LED-valaisimen ajurin ja upotetun langattoman järjestelmän avulla vuorokauden ja vuodenajasta riippuvan valaistuksen kontrolloiminen on mahdollista käyttäjän mieltymysten mukaisesti.Toimitusukums geumulets optinen elementti, sälääsäjärämä ja LED-valaisin. Säädettävän white valon lähdeen edä sävätä optinen elementti on konfiguroitu luomaan relative tasainen skööllistä sunlighta sävet spektri. The valaistussystemen make up the optinen elementti, adjustable white valon lähde and värisäädetattva valopaneli. Valkoisen valon lijkeen väritetemperäse on valitävais 2400 ja 6500 kelvinin between. Värisäädettavä valopaneli makäsätätääten sääälisten ääääätätäva valopääleiden luomisen. Valopaneli consists of valojohteeksi muotoilusta diffuusoripanelista. Then RGB, RGBA or RGBW LEDs can be used to create half color, intensity and pattern. Erilaisia vaaläsäsolosuhteita simuloiva LED valaisin eases vuorkausirytmin vaitätmista terveyttä ja volläää parantaen. The LED valaisimen ajurin and upotetun the wireless system autt vuorkauden ja vuodenajasta polvavan valaistusin controloiminen on omligible user's mieltymysten sälla.

Description

A LIGHTING SYSTEM AND LUMINAIRE FOR SIMULATING SUNNY SKY SCENES

FIELD OF THE INVENTION The invention relates to an optical element, a lighting system and a luminaire which provides similar health benefits of natural light and simulates sunny sky scene at different times of the day and year, including both visual and non-visual effects. Such a luminaire can be installed in a room for facilitating circadian regulation and improving personal health and wellbeing.

BACKGROUND TO THE INVENTION Natural light is essential for humans and fundamental for life and of equal importance as water and air. Its presence or lack not only affects circadian rhythms, but also affects humans visually, emotionally and biologically (our visual cortex, the whole of our alertness, wellbeing and performance). Human circadian rhythm and seasonal variation are genetically fixed, but they are regulated to a certain extent by our surroundings, above all by light. The daylight color temperature in fact changes from dawn to dusk and our circadian cycle — follows this change closely. Multiple physiological processes—including those relating to alertness, metabolism and sleep—are regulated in part by the variance and interplay of N hormones involved in this cycle. Recent reports on lighting for human health and well- N being have shown clearly that natural light has strong effect on mood (depression & S anxiety), stress and energy level. = 25 Given that modern people spend much of their waking day (about 90% of their time) E indoors or there might simply be a lack of available bright sunlight in cloudy days or a during winter, most of them suffer too little sunlight exposure during daytime, and too S much artificial light (blue light) in the evening. On the other hand, too much UV exposure N from the sun outdoors can increase risk of skin cancers and eye disease. — Human-centric lighting, a range of evidence-based solutions that illuminate the way to better health, brighter moods, sharper focus, and heightened alertness/productivity everywhere from offices to homes. Studies show that the types of spectra and light level of luminaire can improve human productivity and general health and well-being. Light in the blue range of the spectrum helps human body tell time and stay aligned with circadian rhythms (the natural 24-hour cycle of sleeping and waking). Soft, dim light helps spur creativity, while brighter lights can help our mood and ability to focus, even to the extent of shortening depression-related hospitalizations. To maintain optimal, properly synchronized circadian rhythms, human body requires periods of both brightness and darkness, and lighting patterns that protect circadian rhythms, and an emphasis on color quality (more blue light during the day, less blue light and more red light during the night), not just on brightness. As known from the priot art light therapy lamps typically comprise static white or blue light source. Tunable white light lamp or luminaires generally lack some key chracteristics of natural light such as intensity and visual effects of the sun and sky. Published patent application US2014/0133125A1 discloses a specific luminaire design to provides blue sky — experience, which has a complicated structure, and lack dynamic tunable light. Published patent application US9476567B2 relates to optical elements and a lighting system to create a skylight appearance, while it still lacks dynamic tunable light.

PURPOSE OF THE INVENTION An embodiment provides a lighting system and a luminaire capable of solving the known N state-of-the-art limitations, which not only reproduces natural light but also simulates . 25 — sunny sky scenes throughout the day, including both visual and non-visual effects. The = luminaire allows users to perceive sunny sky scene indoors with the sense of connection to > nature. It can provide similar benefits as natural light without any harmful ultraviolet E radiation for facilitating human circadian regulation and increasing energy levels as well as N improving mood, performance and sleep guality. 3 30 .

DESCRIPTION OF THE INVENTION It is an object of the invention to provide a more cost-effective lighting system and luminaire reproducing natural light without any harmful ultraviolet radiation and simulating sunny sky scene throughout the day, including both visual and non-visual effects.

A first aspect of the invention provides an optical element.

A second aspect of the invention provides a lighting system.

A third aspect of the invention provides a luminaire.

Advantageous embodiments are described herein below.

An optical element in accordance with the first aspect of the invention comprises a surface microstructure on top of transparent substrates (for example, glass, Polycarbonate, etc). The optical element is suitable for use in front of a light source in which a plurality of light emitters are arranged.

The dot-pattern design of the optical element includes a random — distribution to obtain diffused emitting plane, and periodic structure (two-dimensional gratings) to diffract light to simulate the visual effects of the sun.

According to the second aspect of the invention, a light system is provided.

The light system comprises an optical element according to the first aspect of the invention, a tunable white light source with adjustable correlated color temperature (CCT), and a color tunable light emitting panel wherein the tunable white light source is inserted.

The tunable white light source can be configured by using multiple controllable channels to adjust the color temperature of the white light output in the range from 2400 K to 6500 K.

The channels in the tunable white light system may all produce white light, but with varying N colour temperatures, or combination with one channel of amber LEDs to simulate direct . 25 — sunlight over the course of the day, while without any harmful ultraviolet radiation. = The color tunable light emitting panel for simulating various sky scenes includes a diffuser > panel being shaped as a light guide side-lit by an array of light emitters, as an example, by E an array of red, green and blue (RGB) semiconductor light-emitting diodes (LEDs) that can N be individually varied in output to create the desired color, intensity and pattern.

The S 30 diffuser acts as a light emitting surface which has a relatively uniform light emission N distribution along its surface, which can be fabricated directly on the surface of the light guide or using a sheet of diffuser.

The light guide comprises a light output window and light input window and light outcoupling structures and reflective surface or reflector on one side. The light input window is arranged to receive light from a plurality of RGB or RGBA or RGBW LEDs. According to a third aspect of the invention, a LED luminaire is provided which comprises the optical element according to the first aspect of the invention, and a lighting system according to the second aspect of the invention, and LED driver for driving LEDs to illumination, and a computer (embedded system) with wireless connectivity for controlling the spectral and illumination output of the luminaire, which are coordinated with the local time or user preference to facilitate the coordination of human circadian rhythms and — increase energy levels as well as improve mood, performance and sleep quality. An embodiment of the present luminaire allows for the user to perceive sunny sky scenes indoors with the sense of connection to nature. These and other aspects of the invention are apparent from and will be elucidated with reference to the embodiments described hereinafter. It will be appreciated by those skilled in the art that two or more of the above-mentioned options, implementations, and/or aspects of the invention may be combined in any way deemed useful.

N LIST OF THE FIGURES . 25 FIG. 1 schematically shows an optical element according to the first aspect of the = invention; > FIG. 2 schematically shows a lighting system according to the second aspect of the E invention; N FIG. 3 schematically shows a cross-section of a lighting system according to some S 30 embodiments; N FIG. 4 schematically shows a cross-section of a lighting system, wherein the white light source in behind the light guide;

FIG. 5 schematically shows a cross-section of a further lighting system, wherein backlit by a plurality of RGB LEDs.

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 schematically presents dot-pattern construction of an optical element 101 according to the first aspect of the invention. The optical element 101 is configured in front of a tunable white light source in which a plurality of light emitters are arranged inside an optical cavity. The optical element forms a light emitting surface, and LEDs are arranged to emit light towards it. The dot-pattern of the inner region 102 acts as a diffuser to obtain a relatively uniform light emission and to prevent hot spots from being visible to the viewers; the dots near the edge 103 form two-dimensional gratings to diffract light, simulating the visual effects of the sun. The microstructure (dot-pattern) can be imprinted on top of transparent (to visible light) substrates available. The total domain of the microstructure can be divided into a given number of individual cells, and each cell contains one or several dots. And their radius is in the range of several nanometers to hundreds of microns. Equal radius is assigned to every dot. In the center region 102, the totally two-dimensional random-dot distribution is obtained to distribute the light emitted from the LED sources uniformly across the emitting surface. In the edge areas 103, the dots are aligned in rows and columns separated by — constant pitches acting as two-dimensional gratings. Optionally, the surface microstructures can be molded on the substrate itself, for example, a plurality of periodic holes fabricated through the substrate in the edge areas 103. Optionally, other type of microstructures based on the similar design can be implemented. S FIG. 2 schematically presents a lighting system 200 according to the second aspect of the = 25 invention. The lighting system 200 comprises an optical element 101 according to the first oO aspect of the invention, a tunable white light source 201 in which a plurality of light > emitters are arranged in an optical cavity, and a color tunable light emitting panel 202 E wherein the tunable white light source 201 is inserted. The color tunable light emitting N panel 202 is an edge-lit light guide with light outcoupling structures, light input windows S 30 and reflective surface on the bottom side. N FIG. 3 schematically presents a cross-section of a lighting system 200 according to the second aspect of the invention. The tunable white light source 201 for simulating direct sunlight throughout the day is configured by using multiple controllable channels of white

LEDs to adjust the color temperature of the white light output in the range from 2400 K to 6500 K. The channels in a tunable-white system may all produce white light, but with varying color temperatures, or combination with one channel of amber LEDs. The color tunable light emitting panel 202 comprises a light guide 301, in which a light output window (light outcoupling structures) 304, light input window, and reflective surface or reflector on the bottom side are arranged. The light guide receives light from the light sources 302 via the light input windows, which propagates in guided-mode inside the guide 301. The light emitters 302 can be, as an example, a linear stripe of color tunable RGB or RGBA or or RGBW LEDs. The LEDs 302 can be individually varied in output to — create the desired color, intensity and pattern. The light guide may be made of a light transmitting material such as, for example, glass or Silicone or PC. The outcoupling structure 304 may, for example, be roughen surface or a diffusely reflective paint applied to the surface of the light guide 301, so that the light emitting surface has a substantially uniform light emission distribution along its surface. Alternatively, surface microstructures, for example, diffuse dots, can be imprinted onto the top surface. Optionally, the outcoupling structure or white painted reflector is implemented on the bottom surface of the light guide 301 and a diffusing film attached to top of the light emitting surface. — Optionally, a linear stripe of color tunable RGB or RGBA or RGBW LEDs is arranged adjacent the tunable white light source 201, attaching to the inner edge of the light guide

301. FIG. 4 schematically presents a cross-section of another embodiment according to the o second aspect of the invention, wherein the tunable white light source 201 with an optical O 25 — element 101 is placed behind the light guide plate 301 wherein a smooth surface region N faces the tunable white light source 201. © Alternatively, the color tunable light panel 202 can be made of an OLED film. The OLED I film is also capable to generate diffused light with controlled color, intensity and pattern. a o FIG. 5 schematically presents a cross-section of another embodiment according to the = 30 invention. A tunable white light source 201 with an optical element 101 has the same N function and structure as that of FIG. 3. The diffuser 502 forms a light emitting surface. N Behind the diffuser, there is arranged a plurality of color tunable RGB or RGBA or RGBW LEDs 501 which directly emit the light towards the diffuser 502. The diffuser 502 is used to obtain a relatively uniform light emission and to prevent hot spots from being visible to the viewers. A LED luminaire according to the third aspect of the invention comprises LED drivers; and a computer (embedded system) with built-in wireless communications capability. The embedded system can be any type of dedicated computer or processor to receive input from a wired or wireless module and provide control signals to other modules and driver. The LED luminaire not only provides similar healthy benefits as direct sunlight, but also reproduce the visual effects of the sunny sky scenes changing over the course of the day to promote human circadian regulation and health/wellbeing with a sense of connection to sunny nature. It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims.

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Claims

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1. An optical element (101) for use in front of a tunable white light source (201) to obtain a relatively uniform light emission and simulate the visual effects of the sun, characterized in that the optical element comprises a microstructure formed on top of transparent (to visible light) substrates available. In the inner region (102) of the optical element (101), dots are arranged in random distribution. In the edge region (103), the dots are aligned in rows and columns separated by constant pitches, forming two- dimensional gratings.

2. A lighting system (200) for simulating sunny sky scenes over the course of the day, characterized in that the system (200) comprises the optical element (101) according to claim 1; and a tunable white light source (201); and a color tunable light emitting panel (202) wherein the tunable white light source (201) is inserted.

3. The lighting system (200) according to claim 2, characterized in that the tunable white light source (201) for simulating direct sunlight comprises a plurality of light emitters (303) arranged inside an optical cavity. The tunable white light source (201) is configured by using multiple controllable channels to adjust the color temperature of the white light output in the range from 1900 K to 6500 K.

4. The lighting system (200) according to claim 2, characterized in that the color tunable light emitting panel (202) for simulating various sky scenes includes a reflector and diffuser panel being shaped as a light guide (301) side-lit by an array of RGB or RGBA or RGBW LEDs (302). The LEDs can be individually varied in output to create the desired color, intensity and pattern.

5. The lighting system (200) according to claim 2, characterized in that the color tunable N light emitting panel (202) comprises a diffuser (502) as a light emitting surface and a N 25 plurality of color tunable RGB or RGBA or RGBW LEDs (501) arranged behind the S diffuser. The LEDs can be individually varied in output to create the desired color, = intensity and pattern. i

6. A LED luminaire for simulating sunny sky scenes throughout the day to facilitate N circadian regulation and improve personal health/wellbeing, characterized in that the S 30 luminaire comprises the lighting system (200) according to claim 2; and LED drivers | for driving said LEDs; and a computer (embedded system) with wireless connectivity for controlling and coordinating relative illumination output with the time of day and year or user preference.

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