[0001 ] The present invention relates broadly to a luminaire for emitting artificial light suitable for controlling the risk of macular degeneration in humans. The invention also relates generally to a method of controlling the risk of macular degeneration in humans.

Background of Invention

[0002] It is recognized that there is the potential for damage to retinal

photoreceptors with long term exposure to relatively low levels of high-energy visible light. The nature of the damage conforms to cell apoptosis being a different type of cell damage created by other wavelengths of light, for example visible light and infra red, which above threshold values can cause thermal damage. In addressing this problem, optical lens manufacturers coat their lenses and use novel polymer technology and tints in the lens material to attenuate or reduce exposure of the eyes to blue light in the range of 380 to 450nm. In non-ophthalmic systems, various methods of using filters to reduce or remove noxious wavelengths of visible light from a light emitting diode light source have also been investigated. The light emitting diode source generates photons which pass through a filter designed to allow specific wavelengths. The light emitting diode source together with the filter thus produces a prescribed assortment of wavelengths that when combined are relatively safe and appear to the human visuo-sensory system as a version of white light.

Summary of Invention

[0003] According to a first aspect of the present invention there is provided a luminaire for emitting artificial light for controlling the risk of macular degeneration in humans, said luminaire comprising:

an artificial light source being of a light-emitting diode type and comprising a plurality of semiconductor layers each inherently designed to generate and emit light at respective of a fixed range of wavelength emission spectrums, said semiconductor layers arranged relative to one another wherein the light emitted from each of said layers at the fixed emission spectrums combines to directly generate and emit artificial light at a predetermined wavelength emission spectrum which is relatively lower in its proportion of high energy visible light;

a luminaire housing being associated with the artificial light source whereby said artificial light when exposed to an individual’s eyes at the predetermined wavelength emission spectrum via the artificial light source and the luminaire housing is effective in controlling the risk of macular degeneration in the individual’s eyes.

[0004] Preferably the plurality of semiconductor layers is in the form of a grid of light emitting diodes each designed to generate and emit light at respective of distinct wavelength or colour spectrums corresponding to the fixed range of wavelength emission spectrums. More preferably the grid of light emitting diodes combine to directly generate and emit the artificial light at the predetermined wavelength emission spectrum which is also higher in its proportion of wavelengths at or around 480nm relative to neighbouring wavelengths.

[0005] Preferably the luminaire also comprises an electronic control module operatively coupled to the artificial light source to control emission of the artificial light generated at the predetermined wavelength emission spectrum. More preferably the electronic control module is configured to vary one or more characteristics of the artificial light including spectral power distribution, correlated colour temperature (CCT), level of illuminance or luminance, exposure period of time, and periodicity of these characteristics. Even more preferably the luminaire further comprises a sensor associated with the artificial light source, said sensor arranged to detect ambient light and operatively coupled to the electronic control module to modulate said one or more characteristics of the artificial light which is thus optimal for protection against macular degeneration. Still more preferably the sensor is configured to communicate with the electronic control module in providing feedback to said control module to adjust at least the wavelength emission spectrum of the artificial light depending on the level of ambient light detected by the sensor wherein said emission spectrum is relatively lower in its proportion of high energy visible light.

[0006] Preferably the wavelength emission spectrum generated by the artificial light source is relatively lower in its proportion of high energy visible light at less than around 455nm. More preferably the relatively lower proportion of high energy visible light is at wavelengths of between around 415nm to 455nm. Still more preferably the high energy visible light at wavelengths of less than around 455nm occupies no more than 5% of the predetermined wavelength emission spectrum of the artificial light.

[0007] Preferably the artificial lighting system is associated with an indoor environment. More preferably the indoor environment is an indoor space of a building and the luminaires are mounted to or otherwise associated with a ceiling or overhead structure of the building. Alternatively, the luminaire is associated with a desktop lamp located within the indoor space being significantly closer to the eyes of the subject.

[0008] According to a second aspect of the invention there is provided a method of controlling the risk of macular degeneration in humans, said method comprising the steps of:

directly generating artificial light from an artificial light source of a light emitting diode type and comprising a plurality of semiconductor layers each inherently designed to generate and emit light at respective of a fixed range of wavelength emission spectrums, said semiconductor layers arranged relative to one another wherein the light emitted from each of said layers at the fixed emission spectrum combines to directly generate artificial light at a predetermined wavelength emission spectrum which is relatively lower in its proportion of high energy visible light;

exposing an individual’s eyes to said artificial light at the predetermined wavelength emission spectrum, said exposure being effective in reducing the risk of macular degeneration in the individual’s eye.

[0009] Preferably the wavelength emission spectrum generated by the artificial light source is relatively lower in its proportion of high energy visible light at less than around 455nm. More preferably the relatively lower proportion of high energy visible light is at wavelengths of between around 415nm to 455nm. Still more preferably the high energy visible light at wavelengths of less than around 455nm occupies no more than 5% of the predetermined wavelength emission spectrum of the artificial light.

[0010] Preferably the step of exposing the individual’s eyes to artificial light involves varying one or more characteristics of the artificial light at predetermined time intervals. More preferably said one or more characteristics of the artificial light include spectral power distribution, correlated colour temperature (CCT), level of illuminance or luminance, exposure period of time, and periodicity of these characteristics. Still more preferably said one or more characteristics of the artificial light are modulated depending on ambient light detected via a sensor associated with the artificial light source.

[0011 ] Preferably exposing the individual’s eyes to the artificial light involves exposure of the individual’s eyes to the artificial light directly generated from an artificial light source within an indoor environment occupied by the individual. More preferably the indoor environment is a building occupied by the individual and the artificial light source is located within the building.

[0012] Preferably exposing the individual’s eyes to the artificial light involves continuous exposure to the artificial light at a range of wavelengths from around 400nm to 720nm being the visible spectrum to the human eye. More preferably the artificial light is characterised by a colour temperature of between around 200K to 6000K.

[0013] According to a third aspect of the invention there is provided use of an artificial light source in the manufacture of a luminaire for controlling the risk of macular degeneration in humans.

Brief Description of Drawings

[0014] In order to achieve a better understanding of the nature of the present invention a preferred embodiment of a luminaire for emitting artificial light suitable for controlling the risk of macular degeneration together with a method of controlling the risk of macular degeneration in humans will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a flowchart illustrating the general steps involved in a method of controlling the risk of macular degeneration according to a preferred embodiment of one aspect of the invention; Figures 2A and 2B are comparative graphs for different luminaires illustrating predetermined wavelength emission spectrums of artificial light emitted in accordance with different embodiments of the invention;

Figure 3 is a schematic illustration of an artificial lighting system for generating and emitting artificial light in an indoor environment for controlling the risk of macular degeneration in humans, the system being in accordance with a preferred

embodiment of another aspect of the invention;

Figure 4 is a schematic illustration of a luminaire including an artificial light source for controlling the risk of macular degeneration in humans, the light source being in accordance with a preferred embodiment of a further aspect of the invention;

Figure 5 is a schematic illustration in perspective of one embodiment of an artificial light source of a light emitting diode type according to the invention.

Detailed Description

[0015] In the flowchart of figure 1 the general steps involved in exposing an individual’s eyes to artificial light to control the risk of macular degeneration include:

1. directly generating the artificial light at 10 at a predetermined wavelength

emission spectrum being relatively lower in its proportion of high energy visible light;

2. emitting the artificial light at 12 at the predetermined wavelength emission spectrum;

3. locating the individual’s eyes within the environment in which the artificial light is emitted at 14.

[0016] In this embodiment the artificial light is directly generated at its

predetermined wavelength spectrum wherein the high energy visible light is at relatively lower proportions at wavelengths less than around 455nm. The individual’s eyes are exposed to the artificial light which is emitted within an indoor environment occupied by the individual. The indoor environment may be in the form of a building occupied by the individual and the artificial light is emitted from an artificial light source located within the building and designed to directly generate the artificial light at the predetermined wavelength emission spectrum.

[0017] Figures 2A and 2B illustrate exemplary wavelength emission spectrums 20 of the invention at which the artificial light is directly generated for deployment in the preferred method of controlling the risk of macular degeneration. The graphs correspond to different artificial light sources of a light emitting diode (LED) type. The exemplary spectrum 20 for each of the LEDs of this embodiment of the invention is shown in solid line detail whereas a conventional spectrum 22 for a conventional LED of a similar design is shown in broken line detail. It can be seen that the wavelength emission spectrum 20 of these examples of the invention substantially simulate the effect of sunlight, and to some extent the conventional LED, with the following exceptions:

1. In figures 2A and 2B, the wavelength emission spectrum 20 directly generated by the artificial light source is relatively lower in its proportion of wavelengths at between 415nm to 455nm;

2. In figure 2A only, the wavelength emission spectrum 20 directly generated by the artificial light source is higher in its proportion of wavelengths at or around 480nm relative to neighbouring wavelengths.

[0018] This modification of indoor lighting recognises the importance of protecting the retina, particularly the central retina anatomically referred to as the macular, from undesirable and potentially damaging radiation in the range of 415nm to 455 nm. In this example the high energy visible light, shown in both of the wavelength emission spectrums 20, of less than around 455nm occupies no more than 5% of the overall wavelength makeup of the spectrum 20 of the artificial light. This high energy visible light is a threat to the long-term health and integrity of the underlying retinal

pigmentary epithelium upon which the retina sits as well as the mRNA which is central to normal cellular metabolism. Long term exposure to high energy visible light being absorbed by the retinal pigmentary epithelium is a risk to the development of macular degeneration, a scarring effect suffered by the macular causative of the most common form of legal blindness in developed nations typically referred to as macular degeneration. [0019] In this embodiment exposure of the individual’s eyes to the artificial light is at ambient levels of illuminance which substantially simulate sunlight in its chromatic range of wavelengths and is typically in the range of 400nm to 720nm being the range of wavelengths to which the human eye can detect at the retinal level . This means that the simulated sunlight of the generated artificial light is characterised by a correlated colour temperature (CCT) of between 200K to 6000K.

[0020] Figure 3 illustrates a preferred embodiment of an artificial lighting system 30 according to another aspect of the invention for emitting artificial light in an indoor environment for controlling the risk of macular degeneration in humans. The lighting system 30 is designed to emit artificial light in an indoor space of a building such as but not limited to a classroom, office or lecture room 32.

[0021 ] The artificial lighting system 30 of this embodiment broadly comprises:

1. one or more luminaires such as 34a to 34d designed to generate and emit artificial light without filters at a predetermined wavelength emission spectrum being relatively lower in its proportion of high energy visible light;

2. an electronic control module 36 operatively coupled to the luminaires such as 34a to control their emission of the artificial light.

[0022] Typically the luminaire itself includes a built-in control board which functions as the electronic control module. Alternatively and as illustrated, the electronic control module 36 may wirelessly communicate with the luminaires such as 34a and may be local to or remote from the building 32. Communication of the control module 36 with the luminaires 34a may alternatively be by Ethernet. The control module 36 may be in the form of a computer operated by software or an appropriate app, typically loaded on a tablet or other mobile device. In any of these configurations, the control module 36 is designed to vary one or more characteristics of the artificial light at predetermined time intervals. In line with the preferred method of controlling the risk of macular degeneration, the artificial light may be varied in terms of its spectral power distribution, CCT, level of illuminance or luminance, exposure period of time, and periodicity of these characteristics. The emission of the generated artificial light at the predetermined wavelength spectrum under control of the electronic control module 30 may be effected: 1. manually where an operator at their discretion adjusts the CCT and/or luminance of the artificial light to influence behaviour of individuals exposed to the artificial light; and/or

2. automatically in accordance with a predetermined algorithm or program which may for example adjust the CCT and/or luminance of the artificial light to substantially preserve circadian rhythm.

[0023] In this embodiment the luminaires such as 34a to 34d are mounted to a ceiling of the room 32 or associated with a desktop within the room 32. The desktop luminaires 34d being at a closer proximity to the eyes are designed to generate the artificial light with its emission spectrum of wavelengths limited between around 415nm to 455 nm to guard against or reduce the risk of macular degeneration. The luminaire such as 34a may be equipped with a sensor (not shown) that allows modulation of the variables (spectral power distribution, lux, chromaticity and timing of changes) based on ambient light.

[0024] Figure 4 is a schematic illustration of a luminaire 34 including an artificial light source 40 of one embodiment of the invention. The artificial light source 40 is designed to directly generate and emit artificial light without filters having a

wavelength emission spectrum relatively lower in its proportion of high energy visble light, typically at wavelengths of between around 415nm to 455nm. This exemplary wavelength emission spectrum is illustrated in figures 2A and 2B and it is understood by the applicant that artificial light characterised in this way, and in particular lower in its proportion of wavelengths at between around 415nm to 455 nm, is effective in inhibiting or reducing the risk of macular degeneration.

[0025] As schematically illustrated in figure 5, the artificial light source 40 of this embodiment is of a light-emitting diode type (LED). The LED source 40 includes a plurality of semiconductor layers such as 42a and 42b of an electroluminescent material inherently designed to generate and emit artificial light of a fixed wavelength emission spectrum when excited by electrons. In a conventional manner the semiconductor layers 42a/b are excited by electrons injected by electrical current into the layers 42a/b. Each of the semiconductor layers such as 42a/b thus emits light at the fixed wavelength spectrums and together the layers 42a/b combine to directly generate and emit the artificial light without filters at the predetermined wavelength emission spectrum. The LED source 40 includes electrodes such as 44a and 44b sandwiched either side of the semiconductor layers 42a/b (and possibly other functional layers) for connection to a source of the electrical current. The LED source 40 itself is thus inherently designed and engineered for direct generation and emission of the artificial light at the predetermined wavelength emission spectrum. In this embodiment the individual’s eyes are exposed to the artificial light at the generated predetermined wavelength emission spectrum without any filters or other intermediate barriers for influencing the wavelength emission spectrum of the artificial light.

[0026] The LED source 40 is designed to substantially mimic sunlight generating a range of wavelengths of around but not limited to 400nm to 720nm at the preferred wavelength emission spectrum lower in its proportion of wavelengths at between around 415nm to 455nm. The light source such as 40 of this embodiment is incorporated in a luminaire such as 34 including an electrical assembly 60 connected to the light source 40, and a reflective luminaire housing or hood 64.

[0027] Now that a preferred embodiment of the invention has been described it will be understood that the luminaire and method of controlling the risk of macular degeneration have at least the following advantages:

1. the artificial light source itself is capable of directly generating artificial light at the predetermined wavelength emission spectrum without the necessity for a wavelength filter independent of the light source for reducing light in the damaging high energy visible spectrum;

2. the lighting system and method provide effective exposure to artificial light for reducing the risk of macular degeneration whilst minimising what otherwise would be damaging exposure to natural sunlight known to cause skin cancer and other retinal light damage with over-exposure;

3. the lighting system can be integrated or retrofitted with relative ease to an

existing building without significant changes to existing infrastructure and without requiring any behavioural changes in the individuals occupying the building; 4. the lighting system provides effective control of the key artificial light characteristics in order to effectively manage the control of macular

degeneration in an indoor environment;

5. the method and system lend themselves to controlling other artificial light

characteristics influencing the effect of individuals exposed to that artificial light having benefit for productivity, learning, restlessness and mood.

[0028] Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described.

For example, the levels of illuminance and exposure periods disclosed may vary provided the necessary effect in reducing the risk of macular degeneration is achieved. The wavelength emission spectrum of the artificial light generated may vary from that disclosed provided it is nonetheless lower in its proportion of high energy visible light. The construction of the artificial light source may vary from the embodiments described where for example a combination or grid of LEDs each of a distinct wavelength or colour spectrum (such as Red, Green, Blue) combine to together generate“white light” of the predetermined wavelength emission spectrum. All such variations and modifications are to be considered within the scope of the present invention the nature of which is to be determined from the foregoing description.