Patent Application
20170030552
Not applicable
Not applicable
Field of Invention
This invention relates to the field of light and energy efficiency, of providing more illumination for unit of used electric energy. This invention also relates to the field of room luminaires and space illumination in general, specifically to LED luminaires.
Discussion of Prior Art
We start this section with the definition of the most important terms we use, in order to comply with the USPTO requirement of the use of “exact terms” and also for not to leave room for misunderstandings of the meaning of our words as used in this document. Firstly here we specify some key terms we use, then some of the abbreviations used in the figures, with their precise definition too.
Diffuse reflection also known as non-specular reflection is the reflection on a surface such that incident light is reflected to all directions, though not necessarily isotropically. Most white walls are diffuse reflectors. Also, in our use here, the definition generally does not imply perfect diffusiveness, but is acceptable when the reflection is more-or-less diffuse, that is, when there is preferential reflection towards some angles, as long as this anisotropy is small. cf. with specular reflection. (see
Divergence angle—when applied to a directed light emitting device, divergence angle measures the angle which encompass the majority of the photons emitted by the source. Following general practice, we here use “majority of” meaning 1/e=˜1/2.7182818=˜0.36788=approx 37% of the total light energy emitted within a cone with apex angle equal to the divergence angle, with the light source at the apex.
E26-E27 There is a lot of confusion about the use of these names, and no agreement on their meaning. Therefore we here define only our meaning of the words used according to the best we could have determined to be the use by most people. E26 is the technical name of the American standard household incandescent light bulb socket, which seems to mean 26 mm, which is said to be 1 inch. In reality 1 inch is 2.54 mm, which would be approximated to 2.5 mm not to 2.6 mm. We do not know the history, etc of this. It appears that E26 is the standard adopted in US, Canada, Central and South America (excluding Brazil), Japan and Taiwan. E27 is the similar standard used in Europe and most of the world, and it seems that it stands for 27 mm. These bulbs are more-or-less interchangeable, because the difference is small and there are a few threads only. We will be using the name E27 because it is the standard adopted in most of the world, while it will be understood that what is stated for E27 applies equally well to E26. It appears that E stands for Edison (Thomas Alva Edison). (cf. Edison screw)
Edison screw. Name of the mechanical/electrical standard for the screw base used for the common incandescent light bulb which is the almost universal light producing device in US. Europe uses an almost equal size, with same pitch but 1 mm wider. (cf. E26-E27)
Electromagnetic wave. Any of the oscillations of an electric field and a magnetic field described by Maxwell's equations, which include as a special case the visible light but also many other types, as gamma rays, ultraviolet light, infrared light, microwave, radio waves and more.
Iluminance is defined as the total luminous flux (q.v.) incident on a surface, per unit area. It therefore measures the amount of incident light that illuminates the surface corrected by the luminosity function that measures the physiological perception of light as detected by the human light detectors (cones and rods). By “corrected” we mean that light of longer wavelengths, say, λ=690 nm, a deep red, near the edge of detection by human eyes, is detected with an 8% relative efficiency (relative here means compared with the efficiency of the detection system of a human at the green λ=555 nm, which it the maximum efficiency for humans) then the electromagnetic energy at this wavelength is multiplied by 0.08 (8%) to account for this small efficiency of detection at its wavelength. The limiting case of the correction is the case of electromagnetic waves outside the visible window, say, infrared and ultraviolet, in which case the multiplying factor is 0 (zero), because these electromagnetic waves are not detected by the human eye. The correction is applied at the luminous flux step. (cf. luminance and luminous flux).
LED. Abbreviation of Light Emitting Diode. The name is misleading because there are LEDs that emit in other regions of the electromagnetic spectrum beyond the visible, as the ultraviolet and infrared. When we use the term LED we mean the general use of the term, meaning any wavelength produced by LEDs, visible and beyond, and when we refer to LED light we are also simply using the established practice of using light as a synonym of any electromagnetic radiation produced by the LED. This is a common practice, also used in LASERs, which is an abbreviation of Light Amplification by Stimulated Emission of Radiation, but there are LASERs emitting radiation from the X-ray, through the ultraviolet, the visible, the infrared to the micro-wave parts of the electromagnetic spectrum.
LED chips Light Emitting Diode chip, is the name of our creation for the small, typically 2 mm by 2 mm elements that emit light. The chips can be easily seen in most of the clear window LED emitters. These are not chips in the standard use of integrated circuits, but only in the sense of being semiconductor devices (diodes). The name is misleading, because there are LEDs emitting ultra-violet and infra-red electromagnetic radiation, so light in the name should be understood as electromagnetic radiation instead of visible light, a left-over from the initial LEDs, when they were only capable of producing visible light The 2 by 2 mm2 is just typical dimension, the actual size of any particular one may be different.
Louver is a (generally small) protrusion used for controlling the light propagation, generally to block light propagation along some direction or directions.
Luminance of a light emitting surface is defined as the quantity of visible light emitted per unit of surface area of the emitting surface, along a specific direction, as detected by an average H. sapiens. This last proviso means that the luminance value is weighted by the relative or perceived brightness to a person. It is measured in candela per square meters (cd/m**2). It therefore measures the amount of emitted visible light from a specific projected area that propagates along a specific direction. (cf. iluminance and luminous flux)
Luminous flux (also known as luminous power, which is a more intuitive name but which I will not use here because it is less used than luminous flux) is defined as the measure of the perceived power of light as detected by an average fictitious human being. We are here using power in its scientific meaning of energy per unit time. In practical terms this means that the actual electromagnetic energy is multiplied by a factor that measures the relative sensitivity of the human eyes detectors for each wavelength (color) of light. This factor is 1 (one) at the maximum efficiency of the human eye near the green (λ=555 nm, but there is a difference between the photopic and scotopic cases which we leave aside here), decreasing to 0 (zero) at the borders with the infrared and ultra-violet, both of which are invisible to human eyes. Note that even at the maximum efficiency not all photons are detected by the human rods and cones, and the factor is 1 only because it is a relative (not absolute) correction factor. (cf. iluminance and luminance)
Normal incidence is defined in optics and geometry as perpendicular incidence. By convention all angles in optics are measured from the normal, so normal incidence in optics is 0 dgs. (zero degrees).
Shade vs. shadow. These two terms will be used in the text and we use them in the standard way. We define them here not because we are using these words in any unusual way, but only because they are similar yet their place in the understanding of our invention is crucial. For us here “shade” means the cover (the physical object) often used around some light sources, which scatters the light source inside, causing that the full (larger) surface of the shade becomes the origin of the light for the external part of it. Our use of the word “shade” is the physical object often made from thin fabric or paper or frosty glass that often surrounds a lamp inside. “Shadow” means a region of smaller illumination then the surrounding regions, particularly if with a sharp transition in iluminance which results from an opaque object blocking light from reaching the area of the shadow.
Specular reflection is the reflection on a surface such that light incident on the surface at a particular angle θi with the normal is reflected at the angle θr which is equal to θi, but towards the opposite side of the normal. Mirrors are specular reflectors. (see
Some of the abbreviations used in the figures:
E-arm=Extendable arm used to swivel the supporting surface hem1 for redirecting the emitted light.
hem1=stands for hemsphere1, the shape of the main LED chip supporting surface. We will use the term in a more generalized way, even if the supporting surface is not a true hemisphere, so, in the context of this patent disclosure hem1 stands for the structure that supports the LED chips.
supp1=stands for support1, the main supporting structure that also makes all the required electrical connections. There are several possible forms of supp1, each corresponding to one of the existing mechanical/electrical standards. Examples of supp1 are the Edison-screw (E26 and E27) standards for the incandescent bulbs used for home light in US, the long fluorescent tubular used mostly in offices, educational institutions and businesses, the smaller halogen bulbs much in use in Europe, etc.
The electric light bulb was invented by Humphry Davy in 1801-1802, before Thomas Alva Edison was even born. In the intervening years a large number of scientists, engineers and inventors worked on the problem, which was known to be a technologically important one. Examples are James Bowman Lindsay, Warren de la Rue, Frederick DeMoleyns (all British and Scottish), the Russian engineer Alexandr Lodygin, who got a Russian patent in 1874, and the British Sir Joseph Wilson Swan who designed, built, demonstrated in public lectures and used in his home and public buildings lamps that were virtually the same as Thomas Edison's invention.
We have not been able to ascertain if the glass enclosure of Sir Joseph's first light bulb was transparent or frosty (milky, highly scattering), but we much suspect that it was a transparent glass. The glass type used by Sir Joseph (clear or frost) has much to do with our invention, as it will be seen further down in the specifications, because our invention has to do with increasing the area from which the illumination spreads into the space, as in indirect illumination. Though it is generally asserted that Sir Joseph's light bulb suffered from a short life due to the poor vacuum he was able to get at the time, we are not convinced of the truth of this, largely because vacuum pumps have been used for more than 200 years by the time Sir Joseph did his work on the light bulbs.
Some 20 years after Sir Joseph's first light bulb, Thomas Alva Edison “discovered” it again, making another light bulb, also using a carbon filament and also using an evacuated enclosure to avoid oxidation of the carbon filament, everything exactly the same as Sir Joseph's earlier work. Thomas Edison stated that the carbon filament was kept “ . . . in a nearly perfect vacuum, to prevent oxidation and injury to the conductor by the atmosphere.”
Thomas Alva Edison was a good salesman and had no inner objections to pretend to have invented things. For example, when he installed light bulbs in the steamship Columbia it appears that he pretended to have been the inventor of the light bulb. Like the incandescent bulbs still in use in US (incandescent light bulbs are hardly used in the industrialized world anymore) the filament was inside a glass enclosure which allowed the light to escape while keeping the filament in an environment deprived of oxygen, to forestall the filament oxidation. These lamps were considered a marvel, and marvel they were when compared with their predecessors: the candle, the oil lamp and the gas light. Sometime later the clear glass bulb became frosted glass, a feature that has much to do with our invention, because with the clear glass bulb the source of all light was the small filament, causing a very bright source (high luminance), while the frosted glass bulb had virtually the same luminous flux (same light energy) but the luminance (light per unit area) was much smaller because the area of the origination of the light energy was the much larger area of the frosted glass, which in turn makes the source easier on the eyes of people around it and less pronounced shadows as well. This larger area for origination of the light energy caused (1) less discomfort in humans if their line of sight crossed the light source, and (2) less shadows, because with illumination originating from a larger area each object in the room received light from multiple directions. This has to do with our invention, as seen in the disclosure below, because one of the goals of a good illuminating device is to have diffuse light (originating from many points at once, from as large an area as possible), because this causes less shadows and also because it has smaller luminance (less bright).
The figures at the published patents do not really allow one to be sure about the transparency of the glass enclosure of Thomas Edison's first light bulb, but both the patent figure and text, and other indicators as well, point to the glass being near transparent, as a standard household window glass and as some incandescent light bulb available in US still are—but note that the glass of most light bulbs seen in US are now frosted, or milky, to increase the surface area of the light emitter. The inventor suspect, both from general knowledge and from other pictures from other old lamps, that the carbon filament of these earlier lamps evaporated and deposited on the inner side or the glass enclosure, causing that they became progressively darker, with decreasing illumination.
In anticipation to the description of our invention, the inventor saw in Wikipedia a back-reflector for fluorescent lights that indicates that the luminaire engineers are aware of the advantage of emitting light only towards the space that is to be illuminated.
Regarding the luminance (light energy per unit area of emitter), Wikipedia has this to say about the fluorescents compared with the incandescent bulbs: “Compared with an incandescent lamp, a fluorescent tube is a more diffuse and physically larger light source. In suitably designed lamps, light can be more evenly distributed without point source of glare such as seen from an undiffused incandescent filament; the lamp is large compared to the typical distance between lamp and illuminated surfaces.” We will come back to this point when discussing the advantage introduced by our invention, but we want to use this to show that it is well known that there is an advantage of having as large as possible a surface area from which the light spreads through the space, which is one of the advantages of our invention.
Accordingly, one object and advantage of our amazing invention is to make redundant the lamp shades that are designed to prevent too bright a light to hit the eyes of people in the room, which have the deleterious side effect of absorbing light too, therefore decreasing the energy efficiency of the system by 10% and more, depending on the actual material used for the shade.
Another object and advantage of my invention is to avoid the light absorption caused by the light shades, therefore increasing the overall energy efficiency of the light elements, because more of the light produced is available for illumination. The light shades are used for scattering but there is a secondary effect of absorption too, which decreases energy efficiency.
Another object and advantage of my invention is to provide a more evenly distributed illumination in the room, because our invention causes that most of the light energy suffers the first scattering event from a much larger area, therefore increasing the distribution of the energy in point of origination and in direction. A more evenly distributed illumination has a secondary effect of diminishing shadows—because the objects are illuminated from many sides at the once.
If one or more of the cited objectives is not achieved in a particular case, any one of the remaining objectives should be considered enough for the patent disclosure to stand, as these objectives are independent of each other.
A number of LED-based luminaires have been produced recently as part of the general drive to decrease energy use—LEDs are the most energy efficient light producing device available today. This happens because LED-based light is at least and usually more than one order of magnitude (10 times) more energy efficient than old-style incandescent light bulbs (the actual number depends on several factors, so there is no hard number to express the relative efficiency). This energy efficiency is a direct consequence of the physics involved: black-body radiation for incandescents versus energy band gap for LED semiconductors. Nevertheless, little attention has been devoted to factors that are also involved in energy efficiency beyond the physics of the devices, and our invention relates to one of these secondary effects: the desirability of increasing the surface area from which space light is distributed in the space to be illuminated. This goal of increasing the area from which light is injected in the room, is necessary to protect human eyes from an unpleasantly bright light source (just go home and take away the cylindrical shade that surrounds an incandescent lamp at eye level to see the truth of this statement).
Accordingly, the invention discloses specific positions and directions to place the small LED chips, to take advantage of the directionality of the light emitted by the LEDs for a better evenly spread space illumination and for improving energy efficiency. We repeat here that the energy efficiency originating from our invention stems from the elimination of the shades surrounding the light sources, which are source of light absorption. Our invention does not produce more light per unit of energy used by any LED, but rather our invention obviates the need for the common shades, which then eliminates a source of light loss with the same final objective of improving energy efficiency.
To put these savings in perspective, a 10% energy savings, which is a low figure for the energy absorption by the shades, may seem insignificant, but according to the US Department of Energy on its January 2012 publication “Energy Savings Potential of Solid-State Lighting in General Illumination Applications” (http://apps1.eere.energy.gov/buildings/publications/pdfs/ssl/ssl_energy-savings-report_jan-2012.pdf), page 9, the expected total energy savings in 2030 and in US alone, due to the substitution of the projected 74% of current light producing mix for LEDs will be “ . . . 300 terawatt-hours, or the equivalent annual electrical output of about fifty 1,000-megawatt power plants. At today's energy prices, that would equate to approximately $30 billion in energy savings in 2030 alone. Assuming the current mix of generating power stations, these energy savings would reduce greenhouse gas emissions by 210 million metric tons of carbon. The total electricity consumption for lighting would decrease by roughly 46 percent relative to a scenario with no additional penetration of LED lighting in the market—enough electricity to completely power nearly 24 million homes in the U.S. today”. So, 10% of these savings means 50/10=five 1,000-megawatt power plants that will not be built and operated with the adoption of this invention To put this into perspective, the Grand Coulee Dam generates 6,800 MW and Hoover Dam generates 2,100 MW, so the savings from my invention, even using a conservative 10% absorption from the shade is almost equivalent to the Grand Coulee Dam, or equivalent to 2½ Hoover Dams, not bad! As for money, $30 b/10=$3 billion savings per year for the whole U.S., not a trivial amount by any means. Regarding “ . . . completely power nearly 24 million homes in the U.S. today”, at the conservative figure of 3 persons per household this means 72 million persons total, 10% of which is 72 m/10=7 million persons, or the total population of Washington state to have all their lighting needs for free. So, the conservative 10% savings for the elimination of the shades covering light sources is a humongous energy savings.
LED luminaires have been introduced in a world already committed to either the E27 incandescent bulb, also known as Edison-screw bulb, which dominates the home sector, or to the tubular fluorescent lights, which dominates the industrial/commercial/office/educational sector. There are other standards in place, with smaller penetration, which we will barely mention, only because of their smaller commercial importance, but our invention applies to all the technologies, as it will become apparent.
Given the existing committed hardware in place, the newcomers LEDs have little choice other than occupy the existing installed hardware niche, with luminaires that are interchangeable with one of the existing standards, that are plug-compatible with the existing hardware. Accordingly there are LED-based luminaires that can be screwed into the E27 Edison-screw hardware used in home lighting, LED-based luminaires that can be inserted into the long fluorescent tubular lights used mostly in businesses/commercial establishments, and other existing standards as well. We will use the E27, Edison-screw for our main embodiment, but the principle disclosed on our main embodiment can easily be adapted to other standards, so we will mention a few other modifications for the second technology of fluorescent lights, and also a few examples of adaptation to other technologies too.
One of the most distinguishing characteristics of the LEDs luminaires is that they emit light on a fairly small angular aperture—not milliradians as most lasers do, but still a very small angular aperture. It is worth to point out here, for the benefit of the readers with less technical training, that the angular aperture of the LEDs is nevertheless large enough that these devices pose no danger to the eyes—as most lasers do, but it is simply that LEDs are way too bright for comfort for looking directly into them even if they are as low as a few 10 s mW of electrical power. This small angular aperture, in turn, cause that unless the LEDs are extremely dim, e.g., the turn-on light indicators on electronics panels, nobody likes to look directly at them. In reality the inventor have seen a few electronics panel indicators with LEDs that are uncomfortable to look at from a straight line with their direction. We suggest that our reader try this; most panel LEDs are too dim to be uncomfortable, but occasionally the reader will bump into one that is uncomfortable to look at, and panel indicators LEDs are on the mW power range only.
There has been no time to ponder about the differences between the old light emitting technologies that emitted light on all directions (isotropically) and the new LED-based substitutes that emit light on a narrow cone. We believe that one of the reasons of this is the fast introduction of these more energy efficient substitutes, Our invention makes use of the directionality of the LED-based substitutes for the incandescent and fluorescents and others to achieve a better spread illumination. Our invention also protects humans in the surrounding space from the inconvenience of bright light beams at the same time that it makes the former protective shades redundant, thereby increasing the overall energy efficiency of the LED luminaires. This increase in efficiency occurs because the shades also absorb light, so retiring them leave more light available.
This main embodiment is described for use with the Edison-screw E26-E27 incandescent bulb, but the same principles apply for other standards for light producing devices, as the long tubular fluorescent that dominates the office, school and commercial sectors, or the halogen lights, and others. Glancing quickly at
The frosted shades are used because as they scatter the incoming light from the incandescent light bulb inside it, then, after propagating through the thin shade, the light that emerges from the outer surface of the shade is generally isotropically emitted and from a larger surface area than the inside filament surface area. In technical parlance one can say that the luminance of the frosty surrounding shade/container is smaller than the luminance of the incandescent light bulb inside it. It follows that with the addition of the frosty shade, the new light source is easier on the eyes of people around. A side advantage from the larger surface area is less shadows in the room, which is more comfortable for humans. The shades surrounding the incandescent light bulb create less shadows for the same reason of having lower luminance: larger surface area of the shade than the area of the frosted glass envelope of the light bulb, which is larger still than the area of the filament inside. Indeed, each illuminating point in the surface produces its own particular different shadow, and these different shadows average out to a more even, shadowless illumination. This is better for good vision in the space, besides being more pleasant and peaceful for humans. The undesirable problem that comes together with these advantages, which is the reason for the shades to have been introduced, is that frosted shades also absorb light, therefore contributing for energy inefficiencies that are typically on the order of usually more than 10% of the light energy. This inefficiency was not a concern 50 years ago and earlier, nobody thought about the matter then, but today it is different, energy efficiency is now a concern and the elimination of the shades around the light sources would be a welcome improvement. Obviating the shade this invention eliminates a source of energy inefficiency.
Continuing now with the details of our invention,
The above disclosure can be seen in the three figures that compare the old style incandescent bulb alone hanging down from a ceiling at
The operation of the invention is based on taking advantage of the small angular divergence of the light emitted by LED emitters, or LED emitting chips, to obviate the need of the shades that are often used surrounding most incandescent bulbs E27 and most other light sources. It is worth to note that the new LED light source is the first light source that can be commercially produced in large numbers and low price which emits light on a small cone. This elimination of the need for a shade surrounding the LED emitter of our invention is achieved with a combination of knowing the position and orientation of the E27 substitute, and pre-arranging the LED chips in such directions that they only emit light towards directions that are unlikely to cross the eyes of any human in the vicinity while performing the normal activities that are expected to occur. Our invention causes that the original beam of LED light is directed to the high parts of the walls and/or to the ceiling, perhaps also to the floor. From these large area targets light is spread through the room in a form similar to what is known as indirect lighting.
A secondary advantage of using the indirect illumination from the larger area of the walls, ceiling and etc. is that since the illumination enters the space from a larger area when compared with the typical surface area of the shades, it follows that our invention provides illumination virtually with no shadow, which is pleasant for people. The situation is equivalent to the marked shadow of a person in direct sunlight compared to the no-shadow situation of the same person under a tree in a bright day; in the former case most of the light on the person comes from the small angular aperture of the sun, while in the latter case all the light comes from all directions in the sky.
Since the final objective is to prevent bright light sources into the eyes of humans in the space, discarding the shades may be a possibility if the light from the LED sources are directed into such paths that no human eye moving normally in the space is likely to interrupt the path of light between the LEDs and the first scattering surface. This objective was never possible with the former light sources that emits light isotropically, but became possible with the LED light sources for the first time—and this is where our invention comes in. This in turn requires that the first scattering surface be arranged to be the ceiling, the upper wall or the floor, an arrangement which is possible only because the LEDs are fairly directional light sources. This is why the LED chips in the main embodiment of our invention are as it is shown in
Most former light emitting devices used for space illumination emit light isotropically, or at least quasi isotropically. Examples of traditional light emitters are the incandescent bulbs using the E27 Edison-style screw, the fluorescent tube style lights, and the halogen light, all of which emit light more or less equally in all directions (isotropically). Lasers, of course, do not emit isotropically, but lasers are not used for space illumination, so they are out of the group of light sources under discussion here, which are the group of light sources used for space illumination. Though this statement is obvious to everyone, what has not been noticed is that the directionality of the LED emitters affect their use for space illumination, which is the basis for our invention. The operating principle of our invention is the effect of the position and direction of the LED emitting elements on the distribution of light in the space. The operation of the invention is to mount the LED chips in such a supporting structure hem1 that the LED chips emits light towards a diffuse surface, as a wall, or a ceiling, or a floor, along such a path that the light beam has small to zero possibility of being intercepted by the eyes of any human performing the normal activities in the room before reaching the diffuse surface. If this occurs then there is no need for any shade surrounding the LEDs.
Let us analyze each of these by turn. Firstly, the luminance (that is, emitted visible light energy per unit area—see definition above) is a concern for some of the sources, not for all the sources. High luminance is definitely a concern for most of the incandescent bulbs used in homes, particularly for the older clear glass bulbs, while it is a smaller concern for the fluorescent tubular lamps used mostly in commercial buildings and offices. The reason why this is so is that the light emitting surface of the incandescent bulb is the small tungsten filament with a surface area of 1 square-millimeter, while the emitting surface of the fluorescent light tubes is the full surface of the 1 to 1½ in diameter, 3 to 5 ft long (2.5 to 3.8 cm diameter, 100 to 150 cm long) tube, or 2,000 cm-2=200,000 mm-2 area, which is almost a million times larger than the emitting area of the original clear glass incandescent bulbs!, so the luminance (luminous flux emitted per unit area) of the fluorescent tubes was accordingly one million times smaller, being bright but not offensively so. Old incandescent bulbs were originally sold with clear glass envelope, the tungsten filament was visible, and it was very uncomfortable to look at the filament while the lamp was in use. Most people today have never experienced this because by the time of their demise, clear glass bulbs have not been manufactured for a long time—but older people have used them and know it, and this occurred for a very good reason: to avoid bright light into the field of view of people around. Glass enclosures for incandescent bulbs have been made from a frosty glass for many years now, exactly to decrease the luminance of the clear glass bulbs (same luminous flux divided by the larger area of the frosty bulb). In these frosty glass incandescent bulbs, the light emanating from the bulb has been subjected to many scattering events as it propagates through the thin glass enclosure, causing that the effective emitting area is the much larger area of the frosty glass enclosure than the area of the incandescent filament inside the enclosure. Close attention will show the reader that our beautiful invention works on the same vein as the introduction of the frosty bulb, that is, to decrease the luminance, but our invention goes much further, with a much stronger impact.
But even the frosty glass incandescent is borderline to look at directly (the surface area of the bulb is not large enough), which caused that a second, larger scattering surface was introduced surrounding the frosty glass bulb. This second scattering surface take different shapes, according to the location of the source—which turns out to be a relatively important part of our invention, determining, as it does, the several variants of our invention. The reader is referred to the two provisional patent applications associated with this regular application here for more information on the shades. The main embodiment of our patent is for ceiling incandescents attached to the ceiling at a vertical position and facing down, as per
Theory of Reflection/Fresnel Equations
Maxwell's equations and the boundary conditions for the electric and magnetic field describe the behaviour of the electromagnetic waves (including light) at the intersection between two boundaries of different physical properties. In our case the boundary is between air and the painting on the wall, with indexes of refraction n1 and n2, respectively. The reflectance (fraction of light that is reflected) at any boundary separating these two media with different physical characteristics defined by their indexes of refraction, at angle of incidence θi and angle of transmission θt, at parallel (s) and perpendicular (p) polarizations, is given by the solution of the Maxwell's equations with the appropriate boundary conditions, which is known as Fresnel equations, as seen in
Where, on both equations above, the transition from the middle form to the form at the right is a consequence of eliminating θt using Snell's law:
n1*sin θi=n2*sin θt
The graphs for the two Fresnel equations shown in
So, disregarding the small dip for the parallel component, the reflectivity increases with the angle of incidence (universally in physics, the angle arbitrarily measured starting at 0 dgs from perpendicular incidence growing to 90 dgs at grazing incidence). Since the objective here is larger reflectivity, so as to maximize light in the room, we want to maximize larger, or grazing angles of incidence.
There are many alternative embodiments and extensions for our amazing invention, some of which we make explicit here. The simple positioning of the individual LED chips, which alone is enough to spare the eyes of people in the room, may be complemented with the addition of louvers as shown in
Another variation to the main embodiment is to deform hem1 to avoid that the light is emitted too close from being vertical direction (normal incidence on the ceiling), because according to Fresnel equations, normal incidence causes small reflectivity (see mathematical discussion at “operation of the invention above). Generally, grazing incidence is preferred for the first reflecting surface because the reflectivity is larger for larger angles of incidence. After the first reflection, it is generally difficult to force grazing incidence on the reflecting surfaces because by assumption light is then spread on all directions. Fresnel equation is of general validity and is the reason why the sunset is so bright when the sun sets over the ocean (grazing incidence on the water surface), as in
Another alternative is to add a switch to each LED chip or to a group of LED chips, which is capable of turning one LED chip or a group of LED chips on and off, as needed for a particular case, to cause emitting or not emitting light along particular directions. These switches can make fine adjustments on the LEDs that are on the “on” state and which are on the “off” state, therefore selecting some direction of light emission to be off, which may be needed for some particular case. Such switches would be used one time only, at the installation time, and perhaps never again for the life span of the device, which is very long indeed, some 30,000 hours minimum, which, at 5 hours a day amounts to 16 years of use. Therefore these switches need not offer easiness of change of state but rather manufacturing cost should be the deciding factor. Such a switch could be, for example, the type shown in
It may have occurred to the reader that the position of the LED chips on the hemispherical support hem1 of
Another interesting alternative is shown at
Another important alternative embodiment is shown at
θ=p/q(360) dgs
with p<q, so θ<360 dgs. The supporting hemisphere hem1 is also so constructed that it is capable of rotating around its central axis. Rotating the hemispherical support hem1, the LEDs occupying a fraction p/q of the circumference point to any desired angular direction that is necessary, therefore choosing the illumination direction. This is a good feature that allows for local adjustment of the emitted light. For example if p/q=½, then the LED span half of the circumference of hem1. A situation in which such an LED-substitute for incandescent bulbs would be good is the case of nearby dark colored walls, toward which it would be inefficient to emit light, or when much of the wall on one side is taken by windows. Such a half-hemisphere emitting LED would keep the dark walls or the window opening not illuminated. This variation of the main embodiment is shown in
Another variation is for the less common multiple E27 bulbs at the ceiling with the bulbs mounted on a horizontal direction. This is common for cases designed for multiple incandescent bulbs, as 2 or 3 bulbs in the same bay at the ceiling. In this case the best position for the LEDs would be at the forward ending of the support supp1, or forward and backward, as shown in
Another alternative embodiment is to assign a digital address to each of the chips in each LED, which can then be turned on and off, and when turned on to have their luminous power controlled at the will of a human operator with a radio controller at a distance. The controlling device may be similar to a remote control for a stereo or TV, similar to a bluetooth device, and many other possibilities. The particular technology used for the action-at-a-distance is established technology, in this case to send control and address bits to direct a local microcontroller at the light to control electronics circuits that turn on or turn off individual LED chips and to increase or decrease the luminous power of each chip under the control of a human being according to his/her needs.
Another alternative embodiment is to assign a digital address to each of the chips in each LED, which can then be turned on and off, and when turned on to have their luminous power controlled at the will of a human operator with an electrical signal that is transmitted by the electrical mains (120 VAC in US), operating at a different frequency than the electrical mains (different than 60 Hz).
Another alternative embodiment of our invention is adaptations on the LED substitutes for the fluorescent long tubular lights used mostly in offices, schools, stores and government buildings, that is, most non-residential users. These long, tubular fluorescent lights have an almost tolerable luminance, because the light emitting surface area is so much larger than the frosted incandescent bulb. Because the luminance of the fluorescent lights is smaller than a an equivalent incandescent light bulb with the same luminous flux, there exists quite a number of fluorescent tubes that are not enclosed in any extra frosty enclosure, particularly older buildings. Observing the use of fluorescent tubular lights in several places we came to believe that the cases with the fluorescent lights behind a frosted cover seems to be due more for architect's irrational attachment to flat surfaces than for need to further increase the emitting surface area. Much light is lost in these frosted covers, but it seems that the architects do not worry about this.
A possible alternative embodiment for the long tubular fluorescent lights is shown in
Another alternative embodiment of our invention is for use associated with indirect lighting. We want to call the attention of the reader that the so-called indirect lighting is a variation of the standing lamps with shades, both being designed to increase the surface area for a fixed light luminous flux (light energy originating from the inner source, perhaps an E27 incandescent) from which smaller luminance (light emitted per surface area of the ceiling) spreads to the room (or space in general). In fact, with the exception of searchlights and auto and bicycle headlights, all other illuminating device strive for this same goal of creating a large surface area with low luminance light originating system (dim, not bright), the indirect lighting just being up-front with the objective.
As the reader may be guessing now, it is possible to eliminate the light breaker used for indirect lights with the luminaire of our invention, with the same energy savings created with the elimination of the shades for the main embodiment, due to elimination of light absorption in both cases. Two examples of this is seen at
Many other shapes are possible and are intended to be covered by this patent application. The light breakers often have some ornamentation for decoration, which is not part of this invention. In fact, as seen above, illustrated by
An extension of this is to include the rotatable emitter variation of our invention, as seen in
As the reader can now see, many types of LED chips distributions on the body of the substitutions for the E27 can be devised. In practice, due to market considerations some compromise will be made on the LED chip distributions that are sold in the stores, with the possibility of easily making on-order modifications of the ones mass produced.
Another variation (no shown) is to have a mirror on some surfaces that are supposed to become the first reflecting surface, or the second reflecting surface, etc., but not for all reflecting surfaces (if all surfaces were reflecting, the LED beam would eventually reach people's eyes without suffering scattering-spreading events and would therefore be too bright). For example, on the improvement of our invention for the indirect lights at the higher part of a wall, above the LEDs, against the wall, there could be a mirror to reflect any light to the ceiling, where it then would be diffusively scattered. Stating the same thing in different words, a mirror attached to the upper part of the wall and above the LEDs would specularly reflect all the light falling on it towards the ceiling, from where the light would be diffusively reflected to the room at low luminance.
As the reader probably have noticed, other positions and heights of the Edison socket require different positions of the LED chips on the supporting structure. Each direction and height of the Edison socket requires a different LED arrangement in order to (1) keep the light beam emitted by the LEDs outside the path where the eyes of people may pass, as, for example, predominantly above or below the eyes of the people in the room, and (2) avoiding the use of shades that cause absorption, and consequently adversely impact the energy efficiency of the light source.
Other variations are also possible, which are intended to be covered by our invention.
One example of intended use of the main embodiment is for the ceiling vertically mounted LED-substitutes for the dinosaur incandescent bulb known as Edison-screw, E27.
A second example of intended use of the invention is for lamps either standing on the floor or on some piece of furniture.
A third example of intended use of the invention is for lamps behind an upper ceiling light breaker around the room, which exists in some rooms, sometimes called indirect lighting.
A fourth example of intended use of the invention is for fluorescent tube style lamps, of the type usually found in businesses, schools and offices.
A fifth example of intended use of the invention is to substitute for halogen luminaries used for home and shop illumination. These are generally low voltage small sized lamps, easy to substitute by an LED with the appropriate LED direction.
A sixth example of intended use is for bicycle lights. The use of LED for bicycle lights is very advantageous because bicycle lights either run from a battery or from a local generator, both of which can supply a limited power. Whether powering the bicycle light from a generator or from a battery that must be light weight in a bicycle device, it is much better to use less energy. Moreover, many bicycle lights are halogens, because these are more energy efficient than incandescent, and low voltage, easily substituted by the LEDs.
Thus the reader will see that the light emitter of the invention provides a highly reliable, simple, yet economical device that can be used by persons of any age and skill, which, being compatible with the light emitting devices currently manufactured and used, can be inserted in the existing infrastructure with a measurable positive effect on the energy use (popularly said “energy savings”).
While my description contains many specificities, these should not be construed as limitations on the scope of the invention, but rather as an exemplification of one preferred embodiment and a few of the many possible variations of the main embodiment to adapt the concept to the several standard in use and for the several possible uses of the device. Many other variations are possible. For example, the LED chips may be 4 by 4 mm, or 8 by 8 mm, or 1 by 1 mm, or 1 by 2 mm, etc., or many other sizes, without changing the concept of the invention. The LED chips may be of the type that emit visible light, as in the main embodiment, or they may be of the type that emit ultraviolet, or they may be of the type that emit infrared, or any other electromagnetic radiation, without need to alter the fundamental principles of the invention. The main embodiment was described for an indoor use, but the same principles apply for outdoor use, or use inside cavities of difficult access, as inspections of pipes and inside the human body by laparoscopy, and many others.
Accordingly, the scope of the invention should be determined not by the embodiments illustrated, but by the appended claims, by the figures, by the extensions explained in several parts of the patent application, in the associated provisional patent application, in the claims and their legal equivalents.
N/A
This application is a utility patent application based on a previously filed U.S. Provisional Patent Application Ser. No. 62/197,843 filed on 2015 Jul. 28, entitled “Method and means to avoid bright LED beam for ambient illumination directly into human eyes”, and U.S. Provisional Patent Application Ser. No. 62/206,935, filed on 2015 Aug. 19, entitled “Method and means to decrease the visibility of lines and other image artifacts on LED billboards and other illuminated displays and to control the direction of light emitted by individual LEDs”, the benefit of which is hereby claimed under 35 U.S.C. par. 119(c) and incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62197843 | Jul 2015 | US | |
| 62206935 | Aug 2015 | US |
