WO2011036340A1

WO2011036340A1 - Reflector and light fixture utilizing the same

Info

Publication number: WO2011036340A1
Application number: PCT/FI2010/050718
Authority: WO
Inventors: Juha Koivisto; Ate Korkalainen; Ari Salonen
Original assignee: Oversol Oy
Priority date: 2009-09-24
Filing date: 2010-09-17
Publication date: 2011-03-31
Also published as: SE1250237A1; FI20095979A; FI123457B; SE537070C2; FI20095979A0

Abstract

It is presented in the invention a reflector having a dual-curvature design in such a way that in one longitudinal direction a first section of a reflector has a first longitudinal curvature and a second section of a reflector has a second longitudinal curvature, whereupon a point of discontinuity of curvature has been arranged between said sections of the reflector to function as a dividing point of radiation to divide radiation originating from a radiation source that can be installed at one first distance, between a first and a second section of a reflector as lighting in a longitudinal direction according to a radiation pattern of a radiation source in such a way, that radiation propagating in the direction of strong radiation of a radiation pattern has been arranged by means of a reflector to be reflected farther from a radiation source than radiation propagating in the direction of weak radiation of a radiation pattern of a radiation source. The invention further relates to a light fixture utilizing a reflector. The invention further relates to a light fixture system.

Description

Reflector and light fixture utilizing the same

Background of invention

The invention is directed to a reflector according to a preamble of an independent claim concerning a reflector. The invention is further directed to a light fixture according to a preamble to an independent claim relating to a light fixture. The invention is further directed to a light fixture system according to a preamble of an independent claim concerning a light fixture system.

Previously known are many kinds of light fixtures producing radiation falling in the range of wavelengths of the part of electromagnetic spectrum visible to human eye, to be used for lighting both indoors and in outdoor conditions.

In quite a few cases there has been a problem with the low efficiency of the radiation source, in other words only a small portion of the energy delivered to a radiation source will be transformed into radiation suitable for lighting. An example of a low efficiency radiation source is a conventional incandescent light bulb. It has been possible to increase the efficiency by using various special bulbs and fluorescent tubes in light fixtures, wherein special solutions allow efficiency to be raised as much as several times over in comparison to an incandescent bulb. By means of electronic components and, on the other hand, fill gases and wavelength-modifying coatings, it has been possible to further increase the efficiency of gas-filled lamps, but with conventional light sources quite often the ignition time, i.e. the time that elapses from powering them on to reaching their full operational efficiency, may be as high as minutes, where besides turning a lamp off and on repeatedly will also put stress on the lamp structure. A lamp may also become hot by a significant amount while in use, which also, for its part, is putting stress on both the lamp itself and on the mounting and possible shield structures of the lamp.

A solution to said problems in prior art per se has been sought for example by developing LED lights (Light Emitting Diode) by means of semiconductors and light fixtures based thereon. Significant improvement is then achieved in the efficiency, service life, thermal economy as well as ignition time of a light source. However a problem may arise in some applications due to directional characteristics of LED lights, which may cause uneven distribution of light on a large object to be illuminated and/or thus also cause glare in such illuminated objects, where a person working or otherwise staying under the illumination has to look directly into the direction, where the illumination by an LED is the strongest. The problem also exists both with incandescent bulbs and gas-filled lamps. It is then further problematic, that although indirect lighting used in order to avoid glare does in fact reduce glare, it on the one hand also absorbs part of the radiation in a manner that depends on the structure and roughness of the surface to be illuminated and has an effect of reducing lighting. At the time of the priority date of the present application, the applicant is not aware of a publicly known light fixture technique per se, whereby uniform lighting could be provided in a controlled manner with high light source efficiency associated with short ignition time of the light source.

A brief explanation of the invention

The aim of the invention is to solve or at least to alleviate above stated problems in prior art to produce uniform lighting indoors and/or outdoors.

The objective of the invention is reached by means of a reflector according to an independent claim concerning a light fixture according to an independent claim thereof. The invention is further directed to a light fixture according to an independent claim concerning a light fixture. The invention is further directed to a light fixture system according to an independent claim concerning a light fixture system. The invention is further directed to a control program of an independent light fixture, regarding the control program of a light fixture.

Preferred embodiments of the invention are presented in dependent patent claims. Other preferred embodiments of the invention have also been presented in examples as well as in the specification with reference to pictures. The embodiments of the invention may be combined to an extent applicable.

In one solution according to the invention a correction to the directional pattern of a light source is utilized in such a way, that to those directions in which a light source is emitting radiation more strongly in accordance with its radiation pattern, the radiation of the light source is reflected farther away from the light source than those directions, to which radiation from the light source in accordance with its directional pattern is weaker. This is accomplished by means of a reflector according to an embodiment of the invention.

By using advantageously for example LEDs in a radiation source of a light fixture to produce light at high efficiency, it is then possible to utilize the rather strong directional dependency of an LED on the directional pattern, even if the directional pattern was narrow. Construction of a reflector according to an embodiment of the invention is quite simple for LED-based light fixture solutions and the manufacturing is thereby comparatively straightforward.

On the basis of embodiments based on inventive thought, a person skilled in the art could also apply it to radiation sources of a complicated directional pattern, of which those known per se, on the other hand have a worse efficiency. Design of a reflector would possibly then be more complicated, whereupon mounting precision should also be correspondingly greater than for a light fixture with an LED light source using a reflector according to an embodiment of the invention. By means of using LEDs, a simple structure is achieved that is both strong and easy to install and maintain.

Particularly in such embodiments of the invention, where LEDs are used as a light source, it is also possible to tone the color of lighting by using a set of LEDs appropriate for the toning color. Then, according to an embodiment of the invention, it is possible to make corrections to the color rendition index. Then by using in a light fixture even a few, for example red LEDs, it is possible to considerably alter the color rendition index of cold white LEDs. Color rendition index may therefore be corrected both using outdoor light fixtures and indoor light fixtures. Also by means of the color of a protective glass protecting at least partially a light fixture and a radiation source, it is possible to tone the color of the light of a light fixture, provided that losses of the protective glass per se do not have a detrimental effect on the lighting application. Since LEDs also endure switching on and off in an entirely different way from traditional lamps and fluorescent tubes, it is also possible to feed LEDs by pulsing their supply current at sufficiently high frequencies, even up to several kilohertz or even above, whereupon the flicker of LEDs is not perceivable by the human eye. While power is being conserved by affecting the lighting duration of a certain segment of an LED by means of the pulse length, it is also possible on the other hand by means of pulsing to flicker-balance the momentary loading of a power supply by a large set of LEDs. By means of segmenting light fixture LEDs into sets to illuminate with a given pulse, while others do not illuminate, it is possible to adjust light intensity, when the output of light energy produced by a segment is selected individually for segments to be different among segments in one set of segments. In accordance with one embodiment of the invention it is also possible by means of LEDs to implement such light fixtures, which turn on and/or off according to movement of people (also of animals or machines). Then, for example, an entire street need not be illuminated through the entire dark season using full power. As an example, it is possible to save electricity when a motion detector is used to control a light fixture according to an embodiment of the invention, having a reflector according to an embodiment of the invention optimized to utilize a radiation pattern corresponding to a set of LEDs in order to provide uniform lighting in a area intended to be illuminated, for example a street. In order to control lighting in a sensible way, it is useful to utilize a control program in the control unit of a light fixture system of a light fixture, whereby it is possible by using an individual sensor (or a set sensors) to control one or more light fixtures in order to turn them on, off and/or to tone the color of one light fixture, in order that a lighting system could most advantageously be used. By means of control unit settings it is also possible to sustain low power overall lighting, whereupon it is easier for a passer-by to identify his or her way during an otherwise dark time of day. Using street light fixtures it is then possible to sustain for example 20% light level when there are no passers-by on the street, but when a passer-by is detected with a motion sensor, light level around the passer-by can be raised at least to a higher level, if not quite to the full power. In suitable locations it is also possible to turn certain light fixtures off / on to a certain light level.

According a preferred embodiment of the invention, a light fixture radiation source is arranged to be placed symmetrically at the center portion of a radiation dividing point E of the reflector. According to one embodiment of the invention, lighting can be increased around the edges of an illuminated area by means of additional parts in the crosswise direction, but on the other hand by omitting additional parts, a simpler design can be accomplished. Nonetheless by using additional parts, it is also possible to improve the amount of lighting reaching an illuminated area, even if powers of radiation source were reduced.

List of figures

Some preferred embodiments of the invention are presented in further detail in the following, by way of reference to accompanying figures, of which

figure 1 illustrates a preferred embodiment of a reflector according to an embodiment of the invention,

figure 2 illustrates a preferred embodiment of a light fixture according to an embodiment of the invention,

figures 3a-3f illustrate some preferred embodiments related to mounting of a light fixture according to the invention,

figure 4 illustrates a lighting system according to an embodiment of the invention, and

figure 5 illustrates light fixture control according to an embodiment of the invention,

figure 6 illustrates production/storage of electrical energy needed in lighting, for a light fixture according to an embodiment of the invention, figure 7 illustrates an examplary light distribution curve of an LED, and

figure 8 a segmented light source unit according to an embodiment of the invention.

Measures and dimensions in the figures are merely illustrative examples and therefore do not limit the embodiments of the invention solely to the values and/or dimensions according to said examples. To an extent applicable, same reference markings have been used in the figures, unless stated otherwise. The references need not then necessarily be exactly the same ones, which a person skilled in the art will understand based on the context of the embodiment presented.

Detailed explanation of the invention

Presented in Figure 1 there is a reflector according to an embodiment of the invention as consisting of at least a first section 101 and a second section 102, in direct contact with one another via a point of discontinuity E of curvature in longitudinal direction AB. Also presented in the example of the figure there are curved side sections 101a, 101b, 102a and 102b, in order to even more uniformly distribute light originating from a light source also in a transversal direction CD, FG. A reflector according to the example of the figure can be fabricated using a method known per se, for example by compressing or using die casting by arranging the material of the reflector (for example plastic) into the form of the example of Figure 1 by means of a mold, after which burrs are trimmed away to an extent applicable. A reflector can be also fabricated by forging and/or grinding or by otherwise forcing into its shape. A method known per se to be suitable for the forming of selected reflector material, may then be used to fabricate a reflector according to an embodiment of the invention. Numbers 680 and 780 are examples of dimensions in millimeters, without being limited solely to said dimensions or their proportions.

According of Figure 1, a casting/compression piece comprising a reflector according to an embodiment of the invention, has a ledge 100 formed by a burr, as well as other ledge sections 100a illustrating fabrication using a casting/compression method. While the cast piece in the example of Figure 1 is quadrangular, it is not desired in the invention to be limited solely to an embodiment according to the example in the figure. According to one embodiment of the invention, ledge sections 100 and 100a of a reflector are removed in connection with the fabrication of a reflector. Edge leps of ledge 100 is indicated in the Figure. A straight line defined by its direction, and one other straight line ltks defined by the edge, define a plane (leps, ltks), whereby a plane, in a direction perpendicular to it, passing along a straight line AB while intersecting a reflector piece by the dome of its first section 101 and second section 102 defines a longitudinal (AB) cross section and a longitudinal dual-curved profile that confonns to its shape and has a point of discontinuity of curvature at location E. Said point E is a ridge-like formation between said first section 101 and second section 102. Point E seemingly interrupts the curved shape of first section 101, but the shape of the reflector continues curving in the region of the second section 102 in accordance with its curvature. According to one embodiment of the invention, sections 101 and 102 are mutually symmetrical about point E, but it is not desired that the invention be solely limited to that. Also drawn into Figure 1 is a straight line CD, through which a plane that is perpendicular to a plane (leps, ltks), defines a transversal curvature of a first section 101 by means of a cross section of the reflector. Correspondingly drawn into Figure 1 at the location of the dome is also a straight line FG, through which a plane that is perpendicular to a plane (leps, ltks), defines a transversal curvature of a second section 102 by means of a cross section of the reflector at the location of the dome. Although curvatures in the example of Figure 1 are shown in transversal direction to be nearly the same within reading accuracy, it is not desired in the embodiments of the invention to be limited solely to the same curvatures, and the curvatures may be different, even quite deviating, to produce different lighting for an area illuminated by section 101 from that of an area illuminated by section 102. Longitudinal curvatures of sections 101 and 102 do not need to be the same either, even if the example of the figure so indicates. Although a longitudinal curvature is shown to be different from a transversal curvature for sections 101 and 102 in Figure 1, it is not desired in the invention to be limited solely to the example presented, and according to one embodiment of the invention these may be equal or approximately equal.

Side sections 101a and 101b may to an extent applicable be symmetrical in pairs on each side of first section 101 in transversal direction CD. Side sections 102a and 102b may to an extent applicable be symmetrical in pairs on each side of second section 102 in transversal direction FG. According to an embodiment of the invention, a point of discontinuity is located between side section 101a, 101b and section 101 (also correspondingly between section 102 and side section 102a, 102b). According to another embodiment of the invention, said point of discontinuity is rounded and according to one of its variation made to blend into the curvatures of sections 101 and side sections 101a, 101b (correspondingly also of section 102 and side section 102a, 102b), to alter lighting distribution in transversal direction in a corresponding manner. Side section curvatures in the embodiments of the invention are not limited solely to those apparent in Figure 1, and to an extent applicable may be different as well. According to an embodiment of the invention, radiation sources can be installed at the point of discontinuity to produce lighting.

According to an embodiment of the invention, longitudinal curvature of longitudinal direction AB and/or transversal curvature of transversal direction CD, FG is of one of the following shapes: shape of a conic section, shape of an exponential curve, shape of a logarithmic curve, shape of a progressively changing arch, in which the curvature of the arch increases or diminishes by position between the ends of the arch. Curvature per se is inversely proportional to the radius of curvature. According to an embodiment of the invention, longitudinally directed and/or transversally directed curvature and thus corresponding radii of curvature are determined according to the shape of the area to be illuminated, the directional pattern of the radiation source and the height of application based on the principles of optical geometry.

According to an alternative embodiment of the invention, a first section and a second section of a reflector become collectively integrated to the same semi-torus shaped form, in which point of discontinuity E is a cone-shaped vertex, serving as a center of rotation, when a cross sectional line of longitudinal (AB) profile rotates around a straight line going through a point of discontinuity E and thereby produces a semi-torus. A reflector is then better suitable as a component of light fixtures used for lighting of round areas than a reflector according Figure 1. A radiation source is then preferably also rotationally symmetrical, although not solely limited to such. A reflector or a section of it according to an embodiment of the invention is fabricated of material comprising reflector material using a forming method known per se to give a certain shape to an article of thin material, the raw material thickness of which is significantly small compared to other dimensions. Then for example extrusion, injection molding and/or mold casting and vacuum forming to an applicable extent can be considered, as can also mechanical compression against a mold as applicable examples of embodiments, without being solely limited to them or any combination thereof per se. In such embodiments, by thin is then meant a material thickness that is below 10% according to one embodiment, but below 5% according to one other and below 1% according to a third from the longest dimension defined by one plane of the reflector (leps, Itks), measured directly across.

According to one embodiment of the invention, a section of a reflector is coated with a luminescent substance glowing at a wavelength of visible light, but obtains the necessary energy for it from radiation having a shorter wavelength, originating from a radiation source. Coating may then be very thin to reduce losses and to maximize the net benefit of achievable increase in lighting.

In Figure 2 is illustrated the use of a reflector according to an embodiment of the invention in a light fixture, and at the same time the function of the reflector. A reflector has been illustrated with a longitudinal cross-sectional profile taken in the direction of straight line AB, whereupon the side sections have not been included in the illustration for the sake of simplicity. The first section 101 and the second section 102 of a reflector are connected at the point of discontinuity E of the curvature, below which (as observed in the normal direction a picture is read) a radiation source 210 itself is located to produce lighting. For example connection and mounting piece 213 for connecting a radiation source to mounting base 214 may also comprise a control unit 400, and/or an energy source 402 with associated connections. An installation piece may also include a cooling device for the radiation source, for example a passive heat sink or even a fan, which on the other hand consumes electricity. While it is directly apparent from the dimensions of Figure 2, a light fixture having a short base in proportion to the measurements of a reflector (the ones suitable for example as table and/or floor lamp dimensions, but also as dimensions of an outdoor light fixture with a short base), it is not desired that the embodiments of the invention be limited limits solely to dimensions of the example presented or to indoor light fixtures. From what is presented in Figure 2, a person skilled in the art knows, that mounting base 214 and height h2 of the light fixture from mounting base 215 (ground/floor/another level, also including the wall in one embodiment) can be dimensioned to correspond to the dimensions of a street light fixture. Mounting leg dimension per se may be a known standard dimension applicable to dimensions of an outdoor light fixture. In order to also use a light fixture in locations other than indoors, a light fixture may be equipped according to such embodiment for outdoor use. According to one embodiment, a module formed by a reflector and a radiation source (in one embodiment with its cooling device) is equipped to be installed for both indoor and outdoor use. To an extent applicable, equipment may conform to a local standard according to targeted use. A light fixture according to one embodiment of the invention may also be used as an outdoor light, although nothing per se prevents using a light fixture according to an embodiment of the invention as an indoor light fixture, even if the light fixture was equipped to be suitable also for outdoor use. Exemplary hanging light fixture solutions are suitable both in warehouses and also in outdoor spaces.

Radiation source 210 in Figure 2 is at a distance of hi from a point of discontinuity E of curvature (hereafter also point E).

Illustrated in the figure is a set of rays of light, one of which is originating into the direction of arrow 212a and reflecting from section 102 arrow 212b into the direction illustrated by the arrow, far from the light source. Uniform lighting is then obtained by using a light source having a directional pattern according to Figure 7, although the light source is not ideal according to example 2. Direction 0° of Figure 7 is marked in the figure with a thin arrow. One of the rays of light has been presented as heading in the direction of arrow 211a, reflecting from section 101 and continuing in the direction illustrated by arrow 21 lb to the proximity of the light source. For illustrative purposes for sections 101 and 102 some rays of light are drawn differently, but in practice the use of a radiation source with a symmetrical directional pattern (Figure 7) also creates symmetrical reflection and even lighting within the sphere of influence of a light fixture, when a symmetrical curvature also prevails between reflector sections, according to example 2. Therefore according to one embodiment of the invention, by selecting the shapes for reflector section 101 and section 102 in such a way, that their longitudinal curvatures are not symmetrical about point E, it is possible to produce different lighting distribution in the area of section 101 from the area of section 102, unlike when the longitudinal curvatures would be symmetrical about point E. Point E in Figure 2 is a curve in accordance with Figure 1, at the junction point between sections 101 and 102. Illustrated in figures 3a-3f there are light fixtures (300, 301, 302) according to an embodiment of the invention, in which there is a reflector according an embodiment of the invention. The figures also illustrate mounting variations for light fixtures by embodiment, to be placed on a wall, in a ceiling, on a floor/street. According to a set of variations, a light fixture (300, 301, 302) has been produced to be surface mounted, while according to another set of variations, a light fixture (300, 301, 302) has been produced to be recessed either completely or in part into an mounting base to an extent applicable. In one set of embodiments it may then be necessary to protect the light fixture reflector itself and/or the light source mechanically with a protective plate or in some cases even by molding the light source and reflector together into one piece, the light fixture module. A light fixture module may then be clear or, for some application purposes, even slightly diffused and/or otherwise scattering. It will be clear to those skilled in the art, that the connections for an energy source need to be arranged to be connected to an extent applicable. According to one embodiment of the invention, a light fixture module may also be hollow, to an extent applicable, and be produced using some method known per se other than casting.

Illustrated in Figure 3 a is a light fixture 300 according to an embodiment of the invention, having a radiation source 210 at a distance hi from point E between reflector sections 101 and 102. Other parts of the light fixture have not been shown for the sake of simplicity. The light fixture in the light fixture example is a suspended light fixture, arranged to hang for example from a ceiling or a wall arm by means of a chain, rod or a combination of such. Direction of illumination is intended to be shown toward the text "Figure 3a". Presented in Figure 3b is a light fixture otherwise similar to the one in Figure 3 a, where applicable, except the direction of illumination is the opposite, in order to achieve indirect lighting. Illustrated in Figure 3c is a recessed light fixture 301, which, to an extent applicable, is otherwise similar to light fixture 300 presented in Figure 3a, except that it is made to be either recessed or surface mounted. According to one embodiment of a light fixture 301, mounting method may be selected, when a mounting module is made to enable to be either recessed or surface mounted. According to one embodiment of the invention a mounting module comprises a reflector and a radiation source according to an embodiment of the invention to be attached thereto, in order to provide a light fixture according to an embodiment of the invention. Illustrated in Figure 3d is a light fixture otherwise similar to that in Figure 3c, except that it has a light fixture 302 arranged for indirect lighting, whereupon a primary direction of lighting from the radiation leaving from the reflector has been illustrated as away from the text Figure 3d.

In Figure 3e is illustrated a light fixture 300 intended to be mounted at the top of a pole T by means of beam Ol, 02. Light fixture 300 may be a light fixture intended to be mounted stationary into beam Ol or intended to be mounted in a suspended geometry into beam 02, by means of a rod, a chain or a combination thereof. Although the example of the figure has two beams, it is not desired in the embodiments of the invention to be limited to an example according to only two beams, and the quantity of beams may instead be one, three or even more in some other embodiments. While the beams have been drawn to be horizontal, or perpendicular to a pole, it is not desired in the embodiments of the invention to be limited only to a mutual placement of a beam and a pole according to an example. By selecting height h3 to be suitable for the intended use, it is possible to provide heights suitable for different embodiments to provide both indoor and outdoor lighting. In Figure 3f is illustrated a type of light fixture intended for surface mounting on ground surface, street and/or floor.

Although a light fixture in Figures 3a-3f has been illustrated by marking it off using a dashed line according to one embodiment of the invention, it is also possible to illustrate the outline of a light fixture module with a dashed line, without being limited to a quadrangular cross sectional shape shown per se according to the example.

Figure 4 illustrates outdoor lighting to be implemented by means of a light fixture according to an embodiment of the invention. A lighting system according to an embodiment of the invention has at least one light fixture 300 in accordance with an embodiment of the invention. A street light fixture, having light fixture 300, 301, 302 has been illustrated using a pole T and a slanted beam O. A street light fixture per se may also be of a type shown in Figure 2. In Figure 4 a mounting base of a street light fixture of a lighting system according to an embodiment of the invention has a control unit 400 connected to the pole. Another mounting base of a street light fixture of a lighting system according to an embodiment of the invention has an energy source 402 connected to the pole. Arrows with dashed lines illustrate the control provided by a control unit to some street light fixtures 300, 401. A street light fixture 300C in Figure 4 is color-toned by using a set of colored LEDs to tone the color among a set of other LEDs in a radiation source. Similar color toning may also be used in indoor light fixtures according to an embodiment of the invention. While Figure 4 illustrates an exemplary system drawn to only show light fixtures according to an embodiment of the invention, it is not desired, that such lighting systems be excluded from the embodiments of the invention, having also conventional street light fixtures in addition to a street light fixture according to embodiments of the invention.

Illustrated in Figure 5 there is a control provided by a control unit 400 and the design of a control unit. According to one embodiment of the invention, in the control unit 400 there is at least a connection for one of the following control devices:

- a clock (501) arranged for time control,

- a light sensor 502 arranged for control according to illumination,

- a motion detector 503 arranged for motion-based control,

- slave control equipment 504 in order to operate in accordance with external control, and

- control output (505) to provide external control,

- control input (507) to provide external control,

- a regulator controlling the charging of an energy source, in order to control the energy source of a light fixture,

- a service access 506 for making changes to a software corresponding to the control criteria of a controller 400, and

-transmitter/receiver equipment 508 for communication of control settings with some other light fixtures,

to control light production according to the brightness of the environment.

According to one embodiment of the invention, a control unit contains a set of control devices, the set comprising the devices to provide time control 511, the devices to provide light control 512, the devices to provide motion control and the devices to provide slave control according to external control. A microprocessor μΡ controls the operation of the control unit by means of a control program stored in a memory, which is available to the processor and can be updated via service access 506. According to one embodiment of the invention, service access can be controlled by means of transceiver equipment 508. To an extent applicable, these may be wired or also wireless. A control unit can then be arranged to be updated by means of RF transmission, by utilizing radio frequencies in accordance with a known technique per se for their utilization. Several control units may then be updated, while others may be selectively kept unupdated. According to one embodiment of the invention, each control unit in a set of control units has been named digitally. It is then also possible by utilizing a digital signal, in a manner known per se, to update control units in a manner specific to individual control units to control at least one light fixture. The light fixtures may also be named, whereupon a control unit may indicate a specific light fixture and instruct it to turn on/off according to the settings of a control program.

Control output is an output for outgoing signal. Control input is for an incoming control signal. Control input in the example has been isolated from slave control, because the control provided by a control output according to one embodiment is for example arranged to be regionally in effect (for example in a town sector) and thus in some sense universal, whereupon each light fixture can be configured to provide light in regard to its own individual location, but at the same time to take into consideration deviations in nearby local conditions of a light fixture, based on the sensors of its own control unit. Electricity may then be conserved as well. In the example, on the other hand, slave control switches the lights under the control of a control unit to operate unconditionally in accordance with a slave control signal. I/O illustrates a controller, which regulates input and output signals of a control unit according to microprocessor functions, to control the lighting and/or to update the control unit. HIC illustrates a controller for switching high current region voltages and/or currents as needed by light fixtures. Components of the control unit may be integrated to an extent applicable. At least some of the control unit components may comprise programmed components

An energy source of a light fixture according to an embodiment of the invention is illustrated in Figure 6. The light fixture then includes an associated energy source 402, comprising at least one of the following:

- battery 601,

- solar cell 602,

- fuel cell 603,

- wind generator 604,

- electric utility connection 605,

- one of said in a combination to produce lighting.

Then by using LEDs as radiation sources to provide lighting, it is possible to achieve high efficiency, whereupon even a solar cell may in some cases be suitable to be used as an energy source for charging batteries whenever a light fixture is off. Especially if a surface of a reflector could be fabricated from solar cell material, one could then utilize a reflector surface intended to be non-reflective in light fixtures illuminating unidirectionally, but not to the same extent in dual light fixtures having two light fixtures 300 facing one another, intended to be illuminating in opposite directions. In some cases it may also be possible to utilize wind to turn a generator and thereby to charge the batteries of a street light fixture in the daytime. A fuel cell may also be beneficial in some special situations to produce electricity according to one embodiment. For example a fuel cell and/or a generator set comprising a combustion engine may be advantageous as a standby energy source in the event of power blackouts, to illuminate objects with critical needs for lighting in applicable light fixtures. An energy source according to one embodiment may also be a conventional electric utility line or a three-phase power line, but also an another electrical line specifically designed for LEDs.

Figure 7 illustrates a symmetrical light distribution curve for a radiation source. Figure 8 illustrates a radiation source 210 applicable to an embodiment of the invention. It has an exemplary radiation source 210, having LEDs 803, 805. LED 803 is a colored LED to achieve color toning. According to one embodiment of the invention, all of the LEDs of a segment of a radiation source are similar within the limits of a certain manufacturing tolerance. According to one embodiment of the invention, a radiation source has only one segment, but according to another embodiment there are at least two or more. Set 804 of colored LEDs 803 is illustrated by a dashed line. If necessary, set 804 can be controlled by means of a control device of a control unit, independently per se of other LEDs and/or the segments they form. LED segments 801 and 802 can likewise be turned on or off according to control provided by a control device of a control unit. It is not desired, that the quantity of radiation sources and/or LED segments be limited solely in accordance with the example shown, nor the placement of individual LEDs with respect to one another or in a segment, nor the shape of an LED array to be solely according to the example shown. An LED array may also be rotationally symmetrical. According to one embodiment, LEDs of a functional segment may be dispersed as segments to other different segments, for example in connection with color toning. According to one embodiment, some segments may be slightly apart from each other. According to one embodiment, LEDs in a segment have been distributed at random or semi-arbitrarily into an LED array. According to one embodiment of the invention, an LED array of a light fixture has been divided into segments. According to one embodiment of the invention, segments may be of the same size, classified by the quantity of LEDs or the power, but also arranged to provide various light powers with a light fixture, when certain segments are supplied with electricity to provide light power with a light fixture according to settings of a control unit. Example 1

One light fixture according to an embodiment of the invention is arranged as a street light fixture. By means of a control unit it is then possible rum a radiation source 210 on and off at will even at a kilohertz frequency, whereupon a human eye will not notice a flicker in light. Pulse length and/or the distance to the subsequent pulse, the duty cycle, can be adjusted to be suitable. The pulses may also be targeted for certain segments of a radiation source by means of control provided by a control unit. With pulsed current source to provide lighting it is possible to use different LED segments of a radiation source in alternating order, whereupon deterioration of individual LEDs, even if negligible per se, would be more uniform. At the same time it is possible to balance the differences between LEDs. Consumption of electricity and momentary loading on a power supply can also then be brought closer to the average.

All of the LEDs are not needed in the summer for lighting, even if needed in the winter. Based on a signal provided by a light sensor it is possible to measure illumination and to adapt lighting in accordance with control. By means of a clock in a control unit of a light fixture in a light fixture system it is possible to adjust in such a way, that lighting is on at a certain time, for example in Helsinki in winter time from 3:00 P.M. to 9:00 A.M., but in the summer the lighting is on from 11:30 P.M to 3:30 A.M. instead. Correspondingly, north of the Arctic Circle of Rovaniemi, during a certain period in summer there is no need for night time lighting, while in the winter it is possible to set the lighting functional in the daytime as well, at a light power suitable for the period of polar darkness. This can be accomplished, when a suitable calendar function is also implemented by means of the clock of a control unit, but also by using for the light sensor a certain lighting threshold value, below which illumination is on, but above which it is not. Multiple threshold values may even be utilized according to one embodiment, to provide multi-step illumination. A set of criteria for the implementation of lighting can be arranged using logical prerequisites into successive gates, whereupon only a combination that meets all of the prerequisites will in the control unit produce an instruction for a light fixture to illuminate.

According to one embodiment, a motion detector of a control unit is arranged to recognize movement of an object of the size of at least a small pedestrian in its detection zone and to provide a control signal to the control unit, which switches one segment of the radiation source of a street light fixture on if it is i) the correct time of the day, ii) correct illumination for the environment, iii) the correct time of the year and/or (iv) sufficient supply current is available from the light fixture energy source. A light fixture may then be left on for a specific time by means of a timer. A control unit may then also provide control to other nearby street light fixtures that will turn on as a pedestrian goes by. Directional movement of a pedestrian can be identified by means of motion detectors and unnecessary street light fixtures from the direction of arrival may then be turned off after a certain preset time, provided that the motion detector does not detect other movement in the area. Electricity may then be conserved particularly at times when there are few people around, i.e from evening until early morning. Since a street light fixture according to an embodiment of the invention has a light fixture according to an embodiment of the invention, and in it a reflector according to an embodiment of the invention, uniform lighting is provided on the street for the time needed by a pedestrian, and since a radiation source of a light fixture has a set of LEDs, these operate immediately and reach a full light intensity in a fraction of a second. Turning individual LEDs on and off by segments can be controlled in the control unit through which a street light fixture is being controlled. Illumination color can be toned and even the toning can be altered using a single light fixture. Toning of colors may be particularly beneficial indoors, for example to achieve an ambience by illumination. According to one embodiment of the invention, movement of a person walking on a street will be anticipated by means of a control unit of an illumination system adjusting light fixtures to a higher light level in an estimated direction of travel.

While the foregoing describes a street light fixture as an example among the embodiments of the invention, the example may also be utilized in indoor light fixtures to an extent applicable. Particularly also in livestock buildings and warehouses. But also in alarm equipment and systems, that switch illumination on and/or off.

In certain situations a conventional street lamp equipped with a gas-filled lamp would not even have time to properly turn on before it should already turn off/adjust to a certain light level after a pedestrian has already passed by. A conventional street lamp would also suffer from continuous turning on and off operations and its lamp would remain operational for a considerably shorter time than those used in continuous operation, while an LED-based radiation source will simply endure continuous turning on and off overwhelmingly better and will not require a separate igniter. Moreover, uniformity of illumination using a light fixture according to an embodiment of the invention can be made better than using a conventional street lamp in its area of illumination. Example 2.

A radiation source of a light fixture according to an embodiment of the invention in an ideal case is nearly spotlike, whereupon it is possible to divide light from the location of point E through a symmetrical reflector according to an embodiment of the invention to each point in the area to be illuminated that can be reached per se. A light fixture according to an embodiment of the invention is then operated to illuminate an area, where all points of the area receive light from the light source of the light fixture, whereupon the effect of individual LEDs is balanced within the illumination of the area. Color toning by means of colored light sources is then also directed toward an entire area, which thereby will become illuminated with color-toned light, without having colored or otherwise different spots to an detrimental extent caused by direct light sources in an illuminated area. An ideal case according to an embodiment of the invention can in practice be approximated using a suitable radiation source having a symmetry about point E of radiation distribution. Symmetry can be mirror symmetry, but also, especially in an alternative embodiment, rotational symmetry, without being limited solely to said embodiments per se. According to one embodiment of the invention, it is then possible to place segments and/or portions of such in the radiation source geometry in such a way that conditions according to an ideal case in the lighted area can be provided with sufficient precision. Color toning can then be implemented with such sufficient precision, whereby a human eye will not perceive color toning to cause an area illuminated by a light source to be perceived different in color from other sections in the same area.

On the other hand, by using an asymmetrical radiation source, in some embodiments it is also possible to influence accenting of the color tone of certain parts of a lighted area, when segmentation and the placement of colored light sources in it is done in a corresponding manner. Location of the segments may thus be used to a certain extent to achieve modifiable illumination.

According to an alternative embodiment of the invention, curvature of a first section is different from the curvature of a second section in the reflector. Lighting that has a different light level per se can then be provided in those subsections of a lighted area, which receive their light mainly by way of either the first or the second section. Local uniformity of illumination in the illuminated area and/or in a part of it, can be further affected with a coating of the reflective surface of a reflector. By leaving some parts of an area of a reflective section of a reflector uncoated or by otherwise treating them to reflect in a different manner, it is then possible to provide variations to some degree in the illuminated area of a light fixture utilizing such a reflector. According to one embodiment of the invention it is also possible to affect the shape of an illuminated area with the shape of added sections, whereupon by using additional components symmetrically in transversal directions it is also possible to provide a symmetrical illuminated area, but by changing the symmetry and/or by omitting some additional parts, it is also possible to affect the symmetry of an illuminated area accordingly. It is evident to those skilled in the art, that, as technology evolves, the basic idea of the invention may be implemented in many different ways. Thus the invention and its embodiments are not limited to above-described examples and may vary within the scope of the claims.

Claims

1. A reflector (101, 101a, 101b, 102, 102a, 102b), characterized in that it has a dual- curvature design in such a way that in one longitudinal direction (AB) a first section (101) of a reflector has a first longitudinal curvature and a second section (102) of the reflector has a second longitudinal curvature, whereupon a point of discontinuity E of curvature has been arranged between said sections (101, 102) of the reflector to function as a dividing point of radiation to divide radiation originating from a radiation source that can be installed at a first distance, among a first (101) and a second (102) section of a reflector, as lighting in a longitudinal direction (AB) according to a radiation pattern of a radiation source in such a way, that radiation propagating in a direction of a strong radiation of a radiation pattern has been arranged by means of a reflector to be reflected farther from a radiation source than radiation propagating in a direction of weak radiation of a radiation pattern of a radiation source.

2. A reflector according claim 1, characterized in that said first section (101) has a first transversal curvature in a direction (CD) perpendicular to said longitudinal direction (AB) and in that said second section (102) has a second transversal curvature in a direction (FG) perpendicular to said longitudinal direction (AB), in order to direct radiation propagating in a strong direction of a directional pattern of a radiation source farther away in a transversal direction (CD, FG) from a radiation source than radiation propagating in a direction of a signal propagating in a direction of a weak radiation.

3. A reflector according claim 1 or 2, characterized in that in a double-curved design there is additionally at least one added section (101a, 101b, 102a, 102b) having a curvature in at least one or the other of the said longitudinal direction (AB) and transversal direction (CD, FG).

4. A reflector according to claim 1, 2 or 3, characterized in that it has been manufactured using a forming method.

5. A reflector according to claim 4, characterized in that it has been coated with reflective material and/or luminescent substance on the side facing a radiation source.

6. A reflector according to any one of the preceding claims, characterized in that said first longitudinally directed curvature of a first section (101) is different in size from said second (102) longitudinally directed curvature of a second section, to produce a different distribution with a first section (101) of a reflector from that with a second section (102) in a longitudinal direction (AB).

7. A reflector according to any one of the preceding claims, characterized in that said first transversally directed curvature of a first section (101) is different in size from said second transversally directed curvature of a second section (102), to produce a different distribution with a first section of a reflector from that of a second section in a transversal direction (CD, FG).

8. A reflector according to any preceding claim, characterized in that at least one of said longitudinal curvatures and transversal curvatures is a uniform curvature.

9. A reflector according to any one of the preceding claims, characterized in that at least in its first section (101) a transversal curvature of a reflector in transversal direction (CD) or a longitudinal curvature of a reflector in longitudinal direction (AB) is the same as a transversal curvature of a reflector in transversal direction (FG) in a second section (102) of a reflector.

10. A light fixture, characterized in that it (300, 301, 302) has a radiation source (210) placed at dividing point (E) of radiation of a reflector (101, 102) according to any preceding claim.

11. A light fixture according to claim 10, characterized in that it (300, 301, 302) includes a radiation source (210) comprising a set (801, 802, 804) of LEDs, the set containing at least one LED (805).

12. A light fixture according to claim 11, characterized in that in a set (801, 802, 804) of LEDs (803, 805) in it (300, 301, 302) there is additionally a subset (804) of colored LEDs (803) to tone the color of the illumination of a light fixture (300, 301, 302).

13. A light fixture according to any preceding claim, characterized in that it (300, 301, 302) has a control unit (400) for turning lighting on and off, based on criteria established for a control unit (400).

14. A light fixture according to claim 13, characterized in that its (300, 301, 302) control unit (400) comprises at least one of the following control devices:

- clock (501) arranged for time control,

- light sensor (502) arranged for control according to illumination,

- motion detector (503) arranged for motion-based control,

- slave control equipment (504) in order to operate in accordance with external control, and

- control output (505) to provide external control,

- control input (507) to provide external control,

- regulator controlling the charging of an energy source, in order to control the energy source of a light fixture,

- service access (506) for making changes to a software corresponding to the control criteria of a controller (400), transmitter/receiver equipment (508) for functional communication of control settings with control units of some other light fixtures,

to control light production according to the brightness of the environment.

15. A light fixture according to any preceding claim, characterized in that associated with it (300, 301, 302) is an energy source (402), comprising at least one of the following:

- battery (601),

- solar cell (602),

- fuel cell (603),

- wind generator (604),

- electric utility connection (605),

- a combination of above-said configured to produce illumination.

16. A light fixture according to any preceding claim, characterized in that its (300, 301, 302) longitudinal direction (AB) is arranged in a direction perpendicular to a cross section of a street (403) for use as a street light fixture.

17. A light fixture according to any preceding claim, characterized in that, in order to provide a certain radiation intensity in illumination, placement height (hi, h2, h3) of a radiation source (210) is an-anged at a horizontal distance from the mounting location of a light fixture (300, 301, 302) to a base, in order to reflect light from at least one first (101) and/or second section (102).

18. A light fixture according to any preceding claim, characterized in that it (300, 301, 302) has said radiation source (210) and/or reflector (101, 102, 101a, 101b, 102a, 102b) arranged for installation on a wall.

19. A light fixture according to any preceding claim, characterized in that it (300, 301, 302) has said radiation source (210) and/or reflector (101, 102, 101a, 101b, 102a, 102b) arranged for suspended installation.

20. A light fixture according to any preceding claim, characterized in that therein (300, 301, 302) mounting of a radiation source and/or reflector is an-anged to take place by means of a pole (T) having a different height (h3) and/or an associated beam (01, 02).

21. A light fixture according to any preceding claim, characterized in that it is arranged to operate as an indoor light fixture.

22. A light fixture according to any preceding claim, characterized in that it is arranged to operate as an outdoor light fixture.

23. A light fixture according to any preceding claim, characterized in that a radiation source (210) comprises several light sources (805).

24. A light fixture according to claim 23, characterized in that at least one (802) subset of the radiation sources (801, 802, 804) of its (300) radiation source (210) is an-anged as a set of radiation sources, having at least one radiation source in such a way that said subset of radiation sources is arranged to be controlled with a control unit (400) independently of other (801) radiation sources of a light fixture and/or subsets (801, 803) formed by them.

25. A light fixture according to claim 24, characterized in that one of the subsets of its (300) radiation source is arranged to be controlled by means of a set of control devices, the set having at least one control device according to claim 14.

26. A light fixture according to claim 24 or 25, characterized in that a first subset

(801) of radiation sources of a light fixture (300) is arranged to illuminate during such an interval when some another subset of radiation sources is not illuminating (802).

27. A light fixture according to claim 26, characterized in that said interval is dimensioned to be equal to a pulse to be supplied to said subset causing radiation sources of a first subset (801) of radiation sources to become illuminating.

28. A light fixture according to claim 27, characterized in that said interval is different from said dimension of a pulse to be supplied to a subset causing another subset

(802) of radiation sources to become illuminating.

29. A light fixture according to any of the preceding claims 10-28, characterized in that at least one curvature of a first section of its reflector is different from a curvature of a second section, whereupon the curvature of the first section is one of the set of longitudinally directed (AB) curvature, transversally directed (CD) curvature, and the curvature of the second section is one of the set of longitudinally directed (AB) curvature, transversally directed (FG) curvature.

30. An alternative reflector according to any of the preceding claims 1-9, characterized in that said reflector is alternatively of one-piece design in such a way that said first section and another section merge together into a rotationally symmetrical section, whereupon said point of discontinuity as a dividing point is alternatively a spotlike nose of a conical formation, whereby a reflector is arranged to be used to achieve a circularly symmetrical area of illumination by means of a radiation source that can be installed at a dividing point.

31. An alternative light fixture according to any of the preceding claims 10-28, characterized in that said reflector is alternatively of one-piece design in such a way that said first section and another section merge together into a rotationally symmetrical section, whereupon said point of discontinuity as a dividing point is alternatively a spotlike nose of a conical formation, whereby a light fixture is arranged to achieve a circularly symmetrical area of illumination by means of a radiation source that can be installed at a dividing point.

32. An alternative reflector according to any of the preceding claims 1-7, characterized in that at least one of the curvatures of its first section and/or second section in the area of said section is arranged in longitudinal direction and/or in transversal direction by means of a continuously variable function to produce lighting for a section of a different area.

33. A light fixture system, characterized in that it has at least one (300, 300C) light fixture according to any preceding claim.

34. A light fixture system according to claim 33, characterized in that one of its (401) light fixtures according one of preceding claims is arranged to receive control from another light fixture of the system.

35. A light fixture system according to claim 33 or 34, characterized in that one of its light fixtures according one of preceding claims is arranged to provide a control signal to another light fixture of the system.

36. A control program of a control unit of a light fixture according to any of the preceding claims, on a media executable/readable with a computer, in order to define the criteria for the control of the control devices of a light fixture and/or light fixtures belonging to a part of a system, in order to define the amount of lighting, its timing and/or the light fixtures that belong to the scope of the control.