WO2011051542A1

WO2011051542A1 - Illuminator for producing even light on roads and other large areas as well as on illuminated surfaces of various articles

Info

Publication number: WO2011051542A1
Application number: PCT/FI2010/000067
Authority: WO
Inventors: Juha Koivisto
Original assignee: Juha Koivisto
Priority date: 2009-10-30
Filing date: 2010-10-01
Publication date: 2011-05-05
Also published as: FI20090397A0; FI20090397A

Abstract

The invention relates to an illuminator for producing uniform light on roads and other large areas as well as on at least partially light-transparent surfaces of various objects such as billboards, display units and other corresponding objects. The illuminator comprises at least one light source component (1) and a reflector (7), which are arranged with respect to each another such that the reflector (7) collects at least a portion of the intensity distribution emitted by said at least one light source component (1) and reflects the collected light to an area to be illuminated (9,10), Said at least one light source component (1) is a light source the angular intensity distribution emitted by which is known at least for a portion of the emission angle range which is arranged to be collected by said reflector (7), and a reflecting surface (7') of said reflector (7) comprises at least one planar cut or a portion of a planar cut, which is arranged for its shape, such that, on one hand, it always reflects the light beams (I) it collects the farther from the reflector (7) the greater the intensity of the light beam and, on the other hand, at such an angle of reflection that the intensity on at least a desired portion of the area to be illuminated (9,10) will be essentially the same.

Description

ILLUMINATOR FOR PRODUCING EVEN LIGHT ON ROADS AND OTHER LARGE AREAS AS WELL AS ON ILLUMINATED SURFACES OF VARIOUS ARTICLES

FIELD OF THE INVENTION

The invention relates to an illuminator for illuminating streets, roads, parking areas and other large areas and, in ad^¬ dition, for illuminating the illuminated surfaces . of advertisement billboards, display units and other corresponding applica- tions.

BACKGROUND OF THE INVENTION

Light with even intensity distribution is needed in various different contexts. In some cases, as concerning road and street illumination, for example, the uniformity of ^' intensity is defined by requirements set by authorities. Light with even intensity is also needed e.g.^" in connection with illuminating yards, parking areas and sports fields and , further, e.g. in sports halls, warehouses and greenhouses and also, among other, for the back lighting of illuminated billboards, display units and other corresponding applications as well as for illuminating facades of buildings. In many prior art illumination solutions, the intensity of light is typically at its greatest right below the light source and at close proximity thereof, while lighting drastically dims on the illuminated area or surface as a function of distance from the illuminator.

In the case of parking areas and sport fields, for example, the distance between illuminators is typically great. For example, according to prior art, eight meter high lamp poles with high- pressure bulbs, located at a distance of 43-metres from each other, have been used to illuminate roads. This type of illuminator produces a so called even angular distribution so that in between two light poles, the intensity is always inversely square dependent on the distance so that, in the case of this example, the intensity at its minimum is about 1/8 of the highest intensity right below the illuminator. In practice, this appears as a practically dark area in between the light poles. A typical requirement for an illuminator is the capability to produce either a specific intensity profile' or a uniform illumination on the target to be illuminated. In some cases, as in the case of the aforementioned street and road illuminators, both uniformity of the intensity as well as the light pattern to be created are defined in official standards.

Concerning those prior art streetlights which are based on the use of high-pressure bulbs, the light is often times not ac^¬ tively directed to the surface of the road in order to generate any specific intensity profile or illumination. Illuminators of this kind typically comprise, in addition to the bulb, only a lampshade which serves no other purpose than preventing dazzling. Light hitting a lampshade is distributed to the surroundings in a way that an indefinite light pattern and light pollution in the form stray light is created. The intensity profile produced by the illuminator is not even and the illuminator also loses a great portion of the luminous flux generated by the bulb, as a consequence of the lampshade covering a significant portion of the solid angle of the intensity distribu- tion the bulb produces. A typical reflectivity of a painted surface of a lampshade is in the order . of 20%, meaning that most of the light hitting the screen is absorbed and light reflected from the lampshade is distributed to the surroundings in an uncontrolled manner.

Instead of high-pressure bulbs one has begun to use LEDs as light sources, too. A great challenge for the future for the LEDs is to replace the current light sources, concerning both indoor and outdoor illumination. One new field of application foreseeable for the LEDs is e.g. street and road illumination, as well as area-illumination when it is known that restrictions for the use of high-pressure lamps are on their way.

When illuminating adds and advertisement texts according to prior art, it is typical to use either conventional discharge tubes, or high voltage discharge tubes of desired . shapes . Prob^¬ lems related to these light sources include, among others, a relatively short lifetime in outdoor use where temperature va^¬ riations may be great. Problems related to ignition and bright- ness of the discharge tubes and high voltage discharge tubes are due to cold ambient temperature. A short lifetime generates a need for service or replacing the illuminators, which is of^¬ ten difficult in case the illuminators are located high on a wall of a house, for example.

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Because . of e.g. the reasons described above, LED light sources have been used in billboards as well. A typical illuminated billboard Or advertisement sign comprises a casing oh ^'the bottom of which the LEDs are mounted. A surface of the casing on which the light produced by the LEDs falls is for at least in some desired region transparent to light in a desired manner. The purpose is- to achieve a desired surface brightness and as uniform illumination as possible by using the smallest number of LEDs possible. The criterion for the uniformity of bright- ness of the surface is typically 5% of the highest brightness, achieving of which calls for dense placement of the LEDs which, in turn, significantly increases fabrication costs of the billboard . The back illumination of displays is typically made using cold cathode fluorescence tubes or LEDs being placed at an edge of the display to achieve a construction as thin as possible. By this .kind of arrangement, though, it is difficult to generate a uniform illumination on the display.

, A light emitting diode, a LED, emits light essentially from the surface of a semiconductor and thus functions as a so called Lambertian light source the angular intensity distribution of which being proportional to the cosine of the angle between the surface normal and the angle of view. The direction at which the surface emits light the most is that of the surface normal, while that of the least emission is any direction being , at right angels to the surface normal. In order to achieve high energy efficiency it is important that the light produced by a light source can be collected from a solid angle as wide as possible. Specifically . this concerns il^¬ luminators like LED illuminators in which the luminous flux produced by an individual light source is small. Thus, a con- siderable obstacle for the extensive use; of LEDs in applica^¬ tions where high intensity of light is required is just the small output emission of an individual LED. On the other hand, even though LEDs can be considered for several reasons to be superior to conventional illuminator techniques and even though their efficiency has recently increased, it is not necessarily possible to get rid of the problems related to poor light collection, directing the light or dazzling by just replacing a high pressure bulb with a LED.. There are solutions in the prior art in which the light produced by LEDs is collected and directed to the object to be illuminated by a lens or a lens structure. The light emitted by a LED cannot be collected effectively with a lens because of its limited numerical aperture, which makes the solid angle of the light collection small. By a numerical aperture one understands the quotient of the lens aperture and the focal Length. On the other hand, it is not possible to achieve particularly uniform illumination even by directing light beams produced by lenses to different locations on the area to be illuminated because intensity of such a beam is always at the centre of the beam, meaning that there will be brighter spots on the illuminated area, and reflection from those will cause dazzling.

In some cases the LED may be covered with a refractive optical component. The aim of this solution is to -cover the full solid angle Of the LED' s light emission. In practice, the various losses caused by the optics mean that such optics is not capable of collecting and directing light in a very efficient way. Concerning prior art street lights, a reference can be made e.g. to patent publications US 20070253198 and EP 1945007.

^'The goals of this invention relate to light collection effi^¬ ciency of an illuminator and to development of uniformity of the illuminated area produced, as compared to the prior art light sources described above. A specific goal is an illuminator solution which makes it possible to take advantage of the several good properties of LED light sources, even though the invention is applicable even when other light sources are used, especially when using light sources producing a substantially . Lambertian intensity distribution.

The essential parts of this invention are a light source and a - reflector which are arranged with respect to each other such that the reflector collects and reflects light, preferably produced by a Lambertian light source, so that the highest intensity of the intensity distribution, which in, the case of a Lam^¬ bertian distribution is emitted in the direction of the normal to the surface of the light source, is reflected furthest on the illuminated area and as the intensity gets, smaller, light is reflected the closer to the illuminator the smaller the intensity of the light so that the intensity over the whole illuminated area becomes substantially uniform. More generally speaking, the light emitting component used in the- invention as the light source is such that the angular intensity distribu^¬ tion it emits is known, for the least concerning that sector of the emission angle range which is arranged to be collected by said reflector, and such that the reflective surface of said reflector comprises at least one planar cut or a part of a planar cut which is arranged for its shape such that, on the one hand, it reflects the rays of light it collects always the farther from the illuminator the stronger the intensity of the light ray and, on the other hand, at such a reflection angle that the intensity on at least a desired portion of the illuminated area is substantially the same.

The illuminator of this invention may comprise a LED light source or sources, a support structure for mounting the LEDs and for conducting heat, and a reflector unit which may consist of one or several parts. An essential feature of the preferred embodiments of the invention is that the construction and shape of the reflector is such that it is possible to collect in practice the full emission of the light source for example in half-space, and that the shape of the reflector is such that different parts of the reflector collect and reflect light in such a way that the collected and reflected light on the illuminated surface or area corresponds to the intensity required to achieve a uniform illumination on the illuminated surface.

In one preferred embodiment of the invention, a LED unit con- sisting of one or several LEDs illuminates two reflector surfaces, which are connected together or separate, the reflector surfaces illuminating a road, a street, or some other area to be illuminated at opposite directions. In a second preferred embodiment of the invention, the reflector consists of a rotation symmetric component having one continuous surface which reflects light to all directions on the illuminated area or surface. Instead of a true rotation symmetric surface, the reflector surface may also be a component re- sembling for its overall shape a rotation symmetric component but consisting of smaller planar sub-areas. In the illuminators according to the invention and in its preferred embodiments, collecting the emission produced by the light source can be realized with high efficiency, whereby uniform illumination of e.g. roads, streets and other large areas can be realized effectively. The invention makes it possible, for example, collecting essentially all of the light emission of a Lambertian light source and reflecting and directing it to the area to be illuminated and, thus, minimizing stray light and light pollution. For example, the dark area between light poles typical to prior art street lights can be avoided thanks to the invention, and dazzling from the road surface may also be reduced as well as the direct dazzling typical to many previously known illuminators. The essential features of the invention and its preferred em^¬ bodiments are explained in more detail in the appended claims. In the following, the invention and some of its preferred embodiments are described by referring to the accompanying drawings.

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BRIEF DESCRIPTION OF THE DRAWINGS ^' ί

The invention is now explained in more detail in connection with its preferred embodiments and by referring to the accompa- nying drawings, of which

Figure 1 shows a construction of one prior art LED illuminator;

Figure 2 shows an intensity profile of light on an illuminated surface produced by the illuminator according to Fig. 1;

Figures 3, 4 and 5 show typical LED light sources;

" Figure 6 shows a cross section of a construction of two prior art illuminators and of an illuminated surface; Figure 7 shows an intensity profile on an illuminated surface produced by the illuminator shown in Fig. , 6 ;

Figure 8 shows a structure of an illuminated billboard or a light sign according to prior art;

Figure 9 shows a Lambertian intensity distribution in a polar set of coordinates. Figure 10 shows diagrammatically an intensity profile on an illuminated surface produced by a Lambertian light-emitting surface;

Figure 11 shows a cross section of the basic construction of an illuminator according to^■ a first preferred embodiment of the invention seen from a side of the illuminator;

Figure 12 shows a cross section of the basic construction of an illuminator according to a second preferred embodiment of the invention seen from a side of the illuminator;

Figure 13 shows an intensity profile on an illuminated surface produced by the illuminator according to Fig. 12 Figure 14 shows one kind of angular distribution of intensity in a polar set of coordinates which may be produced by an illuminator of the structure according to Fig. 12;

Figure 15 shows an illuminator according to Fig. 11 or 12 in which, the reflector surface consists of. substantially planar parts;

Figures 16 and 17 show cross sections of reflectors of illuminators according to two preferred embodiments of the invention as ,seen from an end of the illuminator; Figure 18 shows, in the viewing direction according to Figs. 16 and 17, intensity profiles that may be produced by the illumi^¬ nators according to Figs. 16 and 17; Figures 19 and 20 show illuminators according to Figs. 16 and 17, in which the reflector surfaces^' consist of substantially planar parts;

Figure 21 shows an axonometric view of an illuminator that may be constructed of the embodiments according to Figs. 11 and 16;

Figure 22 shows an axonometric view of an illuminator that may be constructed of the embodiments according to Figs. 12 and 16; Figure 23 shows an axonometric view of a basic structure of an illuminator according to a third preferred embodiment of the invention;

Figure 24 shows an intensity distribution on an illuminated surface produced by the illuminator according to Fig. 23;

Figure 25 shows an axonometric view of one kind of angular distribution of intensity that may be produced by an illuminator of the structure according to Fig. 23;

Figure 26 shows a planar cut of an illuminator according to Fig. 11 but consisting of substantially planar reflector parts;

Figure 27 shows an illuminator whose reflector is formed when the planar cut of the reflector according to Fig. 26 swings 360 degrees around an axis which is parallel to the normal to the surface of a light source;

Figure 28 shows an illuminator with a reflector formed in sec- tors of the planar cuts according to Fig. 26; Figure 29 shows an illuminator with a light source comprising LEDs arranged in matrix form

Figure 30 shows an illuminator consisting of LEDs placed on concentric circle^'s;

Figure 31 shows a preferred embodiment of the invention for realizing illumination of e.g. an illuminated billboard. DETAILED DESCRIPTION OF THE INVENTION

Fig. 1 shows one prior art LED illuminator arranged to illuminate a surface to be illuminated 9. The illuminator comprises several light emitting semiconductor components 1 arranged on a case-like support structure 8. Each of these light emitting components 1 emit into a- hemisphere a so called Lambertian intensity distribution 33, whereby the highest intensity is directed in the direction of the normal 6 to the surface of the light emitting component 1 and the light rays 2 of lower inten- sity are emitted at an angle with respect to this normal. Looking at the intensity profile 11 on surface 9 presented in Fig. 2, which is_. produced by the illuminator according to Fig. 1, one is able to see that the illuminator according to Fig. 1 produces the greatest and substantially uniform intensity 13 right below the illuminator while the intensity gets substantially smaller the farther away one moves from the illuminator.

Figs. 3-5 show various light sources that produce Lambertian intensity distribution, which light sources comprise a light- emitting semiconductor component 1 and a housing 3. The light source of Fig. 3 comprises a planar window 4 which is transparent to light, through which the rays of light 2 are passed in accordance with the Lambertian intensity distribution, which is symmetric with respect to the normal 6 of the light emitting surface of the light-emitting semiconductor component 1. Fig. 4 shows a conventional power LED whereto a semi-spherical lens 5 is arranged instead of a window 4 according to Fig. 3. As in Fig. 3, the rays of light 2 are passed to a hemisphere symmetrically with respect to the normal 6 of the light- emitting surface in accordance with a Lambertian intensity distribution.

Fig. 5 for its part shows a typical power LED that emits light from several semiconductor components 1. In such a light sour- ce, there is no window but the light-emitting semiconductor components are protected by some appropriate transparent shielding material.

Fig. 6 shows two prior art LED illuminators which are arranged to illuminate a surface 9 to be illuminated. The illuminators comprise one or several light-emitting semiconductor components 1 being arranged on a case-like support structure 8. Each of these light-emitting components 1 emits a Lambertian intensity distribution 33 into a hemisphere, the highest intensity of which is in the direction of normal 6 to the surface of the light emitting component 1, and the rays of light 2 of weaker intensity are emitted at an angle with respect to this normal.

Fig. 7 shows an intensity profile 11 on a_; surface 9 produced by two illuminators according to Fig. 6. It can be seen^' that illuminators according to Fig. 1 produce the highest intensity 35 right below the illuminators while the intensity gets substantially smaller the farther one moves from the illuminators. Figure 8 shows a construction of one prior art illuminated billboard 28, which consists of a casing.29 with a diffuse or semi-transparent cover^' 30 through which light travels. Cases 3 for the light-emitting components 1, in which the light- emitting components 1 lie, have been mounted on the bottom of the casing 29 of the illuminated billboard 28. Figure 9 shows a Lambertian intensity distribution 33 in a polar set of coordinates, emitted to a hemisphere by a planar light-emitting surface of a light emitting unit 1. In the Lambertian intensity profile, the light intensity is at its great- est in the direction of the normal 6 to the light emitting surface, which makes it typical for a light source of this ^' kind to emit a significant portion of its total intensity at a rela^¬ tively small solid angle. In the light source of this type, there is in practice no light emission in the direction which is at a 90 degrees angle to the normal 6 of the surface. The diagrammatical intensity profile of Fig. 10 shows how the intensity of light decreases from its highest value as a function of the emission angle. Fig. 11 shows a planar cut of the basic construction of an illuminator according to one preferred embodiment of the inven^¬ tion seen from a side of the illuminator. The construction ac^¬ cording to Fig. 11 includes a light-emitting, component 1, and a reflector 7 being arranged to the construction so that at least a portion of the emitted light (I) will be directed towards the reflecting surface 7' of the reflector, from where the reflected light (R) will be directed to the area to be illuminated 9. The light-emitting component 1 of Fig. 11 can be considered to produce a Lambertian intensity distribution, in which case e.g. the intensity of a ray (II) being emitted at a small angle with respect to the normal to the light emitting surface will be greater than the intensity of a ray (12) that is emitted at a greater angle. The shape of the reflecting surface 7' is arranged such that a reflected ray (Rl) of greater inten- sity is always reflected farther on the illuminated surface 9 than a reflected ray (R2) of smaller intensity. In addition, the shape of at least some planar cut of the reflecting surface 7' is realized as curved in such a way that, when the shape of the angular intensity distribution produced by the illuminator is known, as well as the fact that the intensity of light decreases as a function of distance the farther the light is re- fleeted onto an illuminated surface, the light intensity on at least a part of the area being illuminated whereto light is reflected will be substantially the same. Fig. 12 shows an illuminator in which the basic structure shown in Fig. 11 is applied and which is applicable for illuminating e.g. roads and streets. In Fig. 12, the horizontal illuminated surface 9 represents, for example, a street or a road extending from left to right and the illuminator is presented as seen from the side of the road. In the illuminator according to Fig. 12, the reflector 7 is arranged to comprise two reflecting surfaces 7' as shown in Fig. 11. The reflector 7 may be construed e.g. of a continuous structure, or of two parts. One preferred embodiment of the invention includes organizing ^■ several illuminators according to Fig. 12 at a distance from each other defined by the size of the illumination pattern generated by the illuminators. This embodiment may be used for realizing an illuminated area, such as a road or a street, of substantially constant intensity in the direction of the illuminators arranged one behind the other. Fig. 13 shows an intensity profile on an illuminated surface 9 in the observation direction presented in connection with Fig. 9, which intensity distribution fulfils e.g. the most recent norms set for street illumination.

. Fig. 14 presents an angular intensity distribution 34 produced by an illuminator on the plane according to Fig. 12. Fig. 15 presents an embodiment of the invention in which the planar cut of the reflector 7 is not continuous as presented e.g. in Fig. 11 but it consists of substantially planar subparts 14. It is possible to realize the essential basic idea of the invention also by this kind of solution as long as the sha- pe of the cut of the reflecting surface as a whole substan- tially corresponds to the surface shape according to the basic idea of the invention. ,

In the above, the structure of the invention has been consid- ered from the direction of one planar cut of the reflecting surface. But if one considers, for example, the application presented above for illuminating roads and streets and one _ views a planar cut of the reflecting surface from the direction of propagation of the road, it is possible to realize the re- fleeting surface e.g. as according to the preferred embodiments of the invention shown in Figs. 16 and 17. For the sake of clarity, the reflection of the rays of light from the reflector 7 is shown in Figs. 16 and 17 only from the other half of the reflector. In these embodiments of the invention, the shape of the planar cut of the light collecting and reflecting surface T of the illuminator differs from the basic idea presented above in that in this case, the light beams of greatest intensity are not reflected far away from the reflector but into its vicinity, and the rays of weaker intensity are reflected in a controlled way to an area 10 a little farther away from the illuminator where weaker illumination is desired. Thus, e.g. in the embodiment shown in Fig. 16, the shape of this planar^' cut of the reflector 7 is realized so that the right shoulder of the road is illuminated by the left side of the reflector 7 and vice versa. In doing so, the light-emitting component 1 does not shadow the light which is reflected from the reflector 7 to the shoulder of the road. Solutions of this type are useful, for example, specifically in the case of street and road illumination ^' where the area 9 to be illuminated brighter is limited in a controlled manner to the roadway or other lanes, and the shoulder of the road or the light traffic route beside the road is illuminated less brightly 10.

Similarly as presented in connection with, Fig. 15, the reflect- ing surface of the reflector may be realized as substantially planar sub-regions also in the planar cuts dealt with in con- nection with Figs. 16 and 17 (the Figs. 19 and 20). Thus, one embodiment of the invention may comprise a reflector structure that consists of, for example, small rectangular reflector elements 14, which as a whole create a surface reflecting light in accordance with the basic idea of the invention.

One embodiment of the invention not presented in the attached Figs comprises arranging a mirror orientating in parallel with the normal to the light-emitting surface of the light-emitting unit 1, between the light-emitting surface and the reflector 7. When considering e.g. the illuminator presented in Fig. 11, such a mirror could be arranged to extend from the left-side end of the reflector 7 to the light-emitting surface of the light-emitting unit 1. With this solution, not only the light of that part of the emission sector of the hemispheric solid directly falling on the reflector 7 can be directed to the surface to be illuminated 9, but substantially also the light emitted in the direction of the corresponding part of a hemispheric solid opposite with respect to_. the normal to light- emitting surface.

A standard SFS-EN 13201 concerning illuminating roads defines brightness and uniformity criteria for the illumination of roads and streets, as well as for illumination of a , shoulder of a road. The definition states that brightness of the illumination on a shoulder of a road should be, at . least 50% of the brightness of a road surface. When realizing the illuminator e.g. with a reflector construction which, as looked at from a first direction corresponds' to the embodiment of the invention shown in Fig. 12 and as looked at from a second direction corresponds to the cut shown in Fig. 16, one ends up with an embodiment by which the highest intensity of the Lambertian angular intensity distribution produced by the light-emitting component can be collected and reflected on the street or the roadway, and the smaller intensity extending obliquely from the illuminator on the shoulder of the road. Fig. .14 shows diagram- matically in a polar set of coordinates the angular intensity distribution 34 produced by an illuminator according to Fig. 12 and Fig. 18 shows diagrammatically the intensity profile produced by an illuminator according to Fig. 16.

Fig. 21 illustrates one embodiment of the invention by an axonometric figure. Here, preferably the illuminator consists of, for example, a LED light source with a component 1 emitting light according to a Lambertian angular intensity distribution, and of a reflector 7. When observing the reflector 7 in longitudinal direction, it collects rays of light being emitted according to the Lambertian angular intensity distribution and reflects the rays of light of higher intensity to the right side end of the illuminated area and the rays of light of smaller intensity to the left-side end of the illuminated area right below the light source. The shape of the reflector 7 as seen from a first direction is realized according to the invention so that the angle at which the rays of light are reflected towards the illuminated surface is a function of the Lambertian , intensity distribution and, as seen from a second direction which is at right angles with respect to the first viewing direction, so that a light pattern is formed on the illuminated surface which is limited for at least its width. Thus, as a whole, both a substantially uniform illumination on the target area or on a part thereof is formed and, on the other hand, an illumination pattern of a desired shape.

Fig. 22 presents, correspondingly, an embodiment of the invention in which a reflector 7 comprises two reflecting surfaces 7' according to Fig. 21. In this embodiment of the invention, the light-emitting component 1 comprises a unit consisting of 'one or more adjustable LEDs and being placed on top of an efficiently heat conducting structure 19. In the case of several LEDs, they may be arranged adjustable independently of one an- other. When two or more LEDs are arranged next to each other or in rows, the illumination may be adjusted e.g. at the edge of the light pattern. For example, in the case of roadway lighting, the illumination of the area for light traffic by the side of the roadway may be adjusted or even turned off. The illuminator according to Fig. 22 may be arranged to have a motion de- tection means (18) to observe the roadway and/or light traffic so that intensity of the illumination or its distribution may be controlled e.g. according to the needs of the light traffic, and a means 17 for measuring intensity of the light reflected by the reflector 7 in order to ease the assessment of the need for maintenance.

Fig. 23 shows one illuminator according to the invention in which the basic structure of Fig. 11 is applied, applicable for illuminating surfaces and areas to be illuminated. In Fig. 23, the illuminator is shown axonometrically as seen from above and the side. The illuminated surface 9 represents a yard, a parking area or other similar area, or an illuminated surface of a billboard or other surface to be illuminated 30. The reflector 7 according to Fig. 23 is formed when the, planar cut of Fig. 11 swings 3.60 degrees around an axis which is parallel to the normal of the surface of the light source.

Fig. 24 presents an intensity profile on an illuminated surface 9 formed by the illuminator according to Fig. 23.

Fig. 25 presents axonometrically in a polar set of coordinates the angular intensity distribution formed by the illuminator according to Fig. 23.. Fig. 26 presents an embodiment of the invention in which the planar cut of a reflector 7 is not continuous as e.g. in Fig. 11 but consists of substantially planar elements 14. The basic idea of the invention may also be realized by this solution consisting of planar reflecting surfaces as long as the overall shape of the reflecting surface substantially corresponds to the surface shape according to the basic idea of the invention. Fig. 27 presents an illuminator according to one preferable embodiment of the invention, wherein the reflector 7 is formed when the planar cut of the reflector according to Fig. 26 swings 360 · degrees around a z-axis which is parallel to the normal of the surface of the light source. Thus, the reflecting surface of such reflector 7 consists of concentric rings 20 the reflecting surface of which in radial direction being substan^¬ tially planar.

Fig. 28 shows an illuminator the reflector of which is formed out of planar cuts according to Fig. 26 in sectors, whereby the reflecting surface consists of substantially planar elements 24.

Fig. 29 shows an embodiment of the invention in which the reflector 7 is rotation^symmetric and the light-emitting component 1 comprises a unit formed of one or more adjustable LEDs, said unit being placed on the top of an efficiently heat con- ducting structure 19. In the case of several LEDs, they may be arranged to be adjustable independently of each other. If two or more LEDs are arranged next to each other or in rows, the illumination can be adjusted ^'not only for changing brightness but also the intensity profile. A motion detection means 18 is arranged to the illuminator shown in Fig. 29 to detect, for example, movement below the illuminator so that the intensity of lighting and distribution of light may be controlled according to the illumination need at a time. The illuminator according to Fig. 29 is also arranged with a means for measuring light intensity 17 of the light reflected by the reflector 7) in order to ease the assessment of the need for maintenance.

Figure 30 shows a _^second embodiment for the light source for the illuminator according to Fig. 29, in which LEDs are placed on concentric rings. The intensity distribution on different areas of the illuminated surface may then be changed by adjusting power of the LEDs .

Figure 31 shows an embodiment of the invention by which a sub- stantially uniform light intensity can be produced e.g. on a partially transparent diffuse surface 30 of various objects. The structure shown in Fig.. 31 consist of a casing 28 in which several units consisting of a light emitting component 1 and a reflector 7 are arranged. The reflectors 7 are arranged on the bottom 31 of the casing and the heat conducting structure 19 is arranged in rows on the light conducting components to form a structure shared by the light emitting components. The light produced by the light emitting components 1 is reflected on a diffuse surface 30 by reflectors 7 and the heat generated by them is conducted away by the heat conducting structure 19.

The arrangement shown in Fig. .31 can be used, for example, for illuminated billboards. The casing 28 needs not to be rectangular but it can be of the shape of any desired text, figure, letter, number or whatever. The illuminated surface may be evenly transparent to light or it may comprise areas of different light transparency. Depending on the application there may be several light source - reflector structures, or just one. The solution comprising several light source - reflector struc- tures can be realized not only by separate units but also such that the reflecting surface is arranged as unified at the bottom of the casing.

The shape of the reflecting surface of the illuminator accord- ing to the invention is thus realized at least on part of its area as a continuous surface dependent on the angular intensity distribution of the light produced by the light source in accordance with a mathematical function, or as a substantially corresponding surface, which collects and reflects light ac- cording to its intensity so that a substantially constant in^¬ tensity profile is produced on at least a portion of the illu- minated area. Put it in another way, the illuminator may also be defined to comprise a reflector at least one planar cut of which reflecting light rays of the greatest intensity coming from the light source to the area to be illuminated furthest away from the illuminator and then the lower the intensity of' the light beam, the closer to the illuminator it will be re^¬ flected, said planar cut being realized such that the intensity on a desired part of the illuminated area will be substantially the same.

Thus, the preferred embodiments of the invention comprise solutions such as those in which the light-emitting component, preferably a LED component, 1 emits light according to a Lamber- tian intensity distribution. The reflector 7 of the illuminator may comprise two reflecting surfaces extending symmetrically at opposite directions from the light source. The reflecting sur^¬ face may be three-dimensional comprising first planar cuts, which produce as presented above an essentially evenly illuminated area and second planar cuts, which delimit the width of the illumination pattern formed by the illuminator. Said second planar cuts may be arranged to reflect light to. the opposite side of the light source than from where they collected it.

In one preferred embodiment of the invention, the illuminator comprises one or several LEDs, one or several reflectors or reflector parts, a. support on which the LEDs are attached as well as electronics for controlling the LEDs, the geometry and positioning of the reflector with respect to the LEDs being arranged such that said one or several reflectors or reflector parts or their combination is arranged to collect and reflect light produced by the LEds so ^'that such portion of the total intensity produced by the. illuminator is directed to different points of the illuminated area that, irrespective of differ^¬ ences in distances between the LEDs and different points on the illuminated area, illumination of essentially even intensity is produced on the illuminated area. Further, an illuminator according to one preferred embodiment of the invention comprises two or several adjustable LEDs arranged next to each other or in at least two rows , preferably so that the individual, adjacent, or LEDS in different rows are arranged to be turned on and off in at least one desired combination. A means is arranged to the illuminator for measuring intensity of the light reflected by the reflector, and on the other hand a motion detection means as well as a control means for adjusting illumination based on a signal received from the motion detection means.

The reflector used in an illuminator according to the invention may comprise a reflecting surface symmetric with respect to an axis of symmetry and comprise a continuous reflecting surface, or one consisting of several parts, said axis of symmetry coin^¬ ciding with a vector orientating parallel with the maximum emission of the Lambertian intensity distribution of the light- emitting surface used in the illuminator.

Claims

1. Illuminator for illuminating streets, roads, parking areas, storage halls and other large areas, as well as one designed for illuminating surfaces at least partially transparent to light of illuminated billboards, display devices and those of other corresponding objects, the illuminator comprising at least one light source component (1) and a reflector (7), which are arranged with respect to each other such that the reflector (7) collects at least a portion of the intensity distribution emitted by said at least one light source component (1) and reflects the collected light to an area to be illuminated (9,10), characterized in that said at least one light source compo^¬ nent (1) is a light source the intensity distribution emitted by which is known at least for that portion of the emission an^¬ gle range which is arranged to be collected by said reflector (7), and that a reflecting surface [1 ' ) of said reflector (7) comprises at least one planar cut or a portion of a planar cut, which is arranged for its shape such that it always reflects the light beams (I) it collects the further from the reflector (7) the greater the intensity of a light beam and, on the other hand, at such an angle of reflection that intensity on at least a desired portion of the area to be illuminated (9,10) .is essentially the same.

2. The illuminator- according to claim 1, - characterized in that the light source component (1) is a component emitting light according to a Lambertian intensity. distribution, such as a LED emitting light according to the Lambertian intensity dis- tribution.

3. The illuminator according to claim 1 or 2, characterized in that the reflector (7) comprises two reflecting surfaces .{I') extending symmetrically in opposite directions from the light source component (1) , and/or a mirror essentially orientating in the direction of normal of a light emitting surface of the light source component (1), the mirror being arranged to extend from said light emitting surface to the reflecting surface (7' ) .

4. The illuminator according to any of claims 1 - 3, characterized in that the reflecting surface (7') is three dimensional and comprises first planar cuts with properties according to claim 1 and .second planar cuts which delimit the width of the light pattern produced by the illuminator.

5. The illuminator according to claim 4, characterized in that said^' second planar cuts are arranged to reflect light to the opposite side of the light source than from where they col^¬ lect it.

6. The illuminator according to any of claims 1 - 5, characterized in that at least a portion of the reflecting surface (7') of the reflector (7) is arranged to- consist of essentially planar regions (14, 24) .

7. The illuminator according to claim 1, characterized in that ^' said at least one light source component (1) is a LED and that the illuminator comprises at least one reflector (7) or a part thereof, a heat conducting support (19) to which said at least one LED (1) is connected, . and electronics designed to control said at least one LED, and that the geometry of said reflector (7) and its placement with respect to said at least one LED is arranged such that said at least one reflector (7) or a portion thereof, or a combination thereof, is arranged to collect and reflect light produced by said at least one LED such that, such portion of the total intensity produced by the illuminator is directed to different places on the surface to be illuminated that an essentially even lighting is produced across the whole illuminated area.

8. The illuminator according tp any of claims 1 - 7, characterized in that two or several light source components (1) are arranged next to each other or in at least two rows, or on concentric circles.

9. The illuminator according to 8, characterized in that individual, adjacent, or the LEDs of the different rows or of the concentric circles are arranged_, to be adjustable and/or to be switched on and off in at least one desired combination.

10. The illuminator according to any of claims 1 - 9, characterized in that a means (17) is arranged to the illuminator for measuring intensity of the light reflected by the reflector

^' (7) . .

.

11. The illuminator according to any of claims 1 - 10, char^¬ acterized in that a motion, sensing means (18) and a control means are arranged to the' illuminator for controlling lighting according to- a signal received from the motion sensing means ■ (18) .

12. The illuminator according to claim 2, characterized in that the reflector (7) comprises a reflecting surface (7') which is symmetric with respect to an axis of symmetry (Z) and is continuous or consist of several parts, the axis of symmetry (Z) uniting with a vector parallel with that of the maximum emission of said Lambertian intensity distribution.

13. The illuminator according to claim 12, characterized in that said reflecting surface (T ) is a rotational symmetric surface about said axis of symmetry (Z) .

14. · The illuminator according to claim 12 or 13, characterized in that the reflecting surface [1 ' ) is for its general shape ,a rotational -symmetric surface but one consisting of smaller essentially planar sections.

15. Illumination arrangement designed for illuminating streets, roads, parking areas, storage halls and other large areas, characterized in that it comprises two or several illumina- tors according to any of claims 1 - 14.

16. Illuminator for illuminating streets, roads, parking areas and other large areas, characterized by a pole or a corre^¬ sponding structure arranged to support an. illuminator according to any of claims 1 - 14.

17. Illuminated advertisement billboard or advertisement light structure, which includes an essentially enclosed casing or a corresponding structure (29), on at least one surface (30) of which is arranged at least one area consisting of material transparent to light, arranged to be illuminated by at least one illuminator arranged within said casing or a corresponding structure (29), characte ized in that said at least one illuminator is one according to any of claims 12 - 14.

18. The illuminated advertisement billboard or advertisement light structure according, to claim 17, characterized in that several of said- illuminators are positioned with respect to each other such that they make up a two dimensional matrix.