EP0605365B1 - Lighting device - Google Patents

Abstract

The lighting device (1) has mounting means (23) for mounting an artificial light source (9), a concave mirror (10) partially enclosing the latter and a translucent dispersion element (17) of, for example, pyramid shape having two dispersion bodies (18) separated from each other by a gap (19). When operating the lighting device (1), light generated by the light source (9) and containing several spectral colours for example more or less white light, is collimated by the concave mirror, radiated at least partly into the dispersion bodies (18) through their boundary surfaces (18d) bounding the gap (19), radiated out again from the dispersion bodies (118) through light exit surfaces (118b) and spectrally decomposed so that, on different sides of the gap (19), light decomposed into its spectral colours is radiated into the surrounding area of the lighting device (1). When it falls upon a surface, this light generates strip-shaped, intense light spectra which have a fascinating effect on an observer. <IMAGE>

Description

The invention relates to a lighting device. This should make it possible to spectrally split light generated with at least one artificial light source and to radiate it into its surroundings.

Illumination devices known from DE-A-2 243 335 have a light source and a dispersion element with at least one arcuate or ring-shaped dispersion body. The dispersion bodies are triangular or trapezoidal in cross section and have a cylindrical inner surface, an at least partially conical outer surface and a flat base surface. One of the lighting devices disclosed in the cited publication has a plurality of annular dispersion bodies arranged one on top of the other. The base of most of these protrudes inward beyond the cylindrical inner surface of the next lower dispersion body.

According to the functional description contained in DE-A-2 243 335, the light radiated in by the light source through the base area of a dispersion body is to emerge from the conical outer surface of the dispersion body in a spectrally decomposed manner and produce a rainbow-like light strip when it hits an object. According to FIGS. 17 to 20 of the publication, the light strikes the base of the dispersion bodies rather steeply. Since there are no collimation means in the lighting devices known from the publication, light is also radiated onto the base of the dispersion body, the angle of which varies with the base in a relatively large range. If part of the through the footprint into one If the dispersion body of the incident light is spectrally broken down, several overlapping spectra can arise, so that the light hitting a specific point often has more or less the original color. It therefore seems unlikely that the lighting devices known from DE-A-2 243 335 can actually produce intense, rainbow-like strips of light. In the case of the lighting device having a plurality of annular dispersion bodies arranged one above the other, the interior of the lighting device containing the light source is also completely closed at the top, so that the heat generated by the light source apparently consisting of an electric lamp during operation can only be dissipated with difficulty and the dispersion bodies during prolonged operation get very hot.

Lighting devices known from DE-U-9 007 017 have lighting units with a light source and a dispersion element which consists of an optical prism which is triangular in cross section or has a diffraction grating. Furthermore, the various lighting units also have collimation means, namely an aperture and two lenses or a concave mirror or a concave mirror and a lens.

The lighting units known from DE-U-9 007 017 all have the disadvantage that each of them can only produce a single, spectrally decomposed bundle of light rays, which moreover very likely has only small cross-sectional dimensions. If several bundles of light are to be generated, several separate lighting units of the type described must therefore be provided, as is also described, as a result of which the entire lighting device becomes expensive. In the case of the variants of the lighting units which have a lens or two lenses In addition, the lenses, the holding means required to hold them, which must enable the lenses to be positioned precisely, and the installation of the lenses cause considerable costs. The light radiated into a prism forms a relatively large angle with the surface through which it is radiated into the prism in all of the described lighting units. Since this is also the case in particular with the lighting unit without a lens, it seems very doubtful for the reason given in relation to the previously described DE-A-2 243 335 whether a reasonably clear spectrum can be generated at all with the lensless lighting unit. Furthermore, the lighting units provided for advertising and known from DE-U-9 007 017 apparently have approximately cuboid supporting structures or housings which are not particularly aesthetically pleasing.

A lighting device known from DE-A-1 597 950 has a hollow base, an incandescent lamp arranged therein and a transparent, truncated pyramid-shaped light diffusion body. This consists of a casting resin with shrinkage cracks and has a trough-shaped depression at its lower end facing the incandescent lamp and a vertical channel opening into the deepest point of the depression. This should serve to guide light and heat and be as invisible as possible.

According to the text of DE-A-1 597 950, the light in the diffusion body is deflected, refracted and broken down several times. Since the light is distributed many times and irregularly due to the shrinkage cracks in the diffusion body, the channel probably consists of a hole with only small cross-sectional dimensions and also there are no means for collimating the light, this lighting device hardly enables light that is broken down into the different spectral colors with clearly visible ones To emit light spectra into the environment.

The object of the invention is therefore to create a lighting device with which disadvantages of the known lighting devices can be avoided. The lighting device should, in particular, enable light that has been broken down into the different spectral colors to be emitted into the surroundings using inexpensive means in such a way that bright, clear and easily visible light spectra are produced, the lighting device should be inexpensive to manufacture and aesthetically pleasing.

This object is achieved by a lighting device which has the features of claim 1 according to the invention.

Advantageous refinements of the subject matter of the invention emerge from the dependent claims.

The lighting device can be designed as a lamp, which, in addition to at least one dispersion element, also has holding means which can detachably hold or at least detachably hold at least one artificial, in particular electrical, light source. The lamp can for example be designed as a floor, ceiling or wall lamp. However, the lighting device can also be formed by a lamp serving as an artificial light source with at least one dispersion element, which is inseparably connected to the remaining parts of the light source or lamp and therefore cannot be removed from the light source without damaging it.

The light source is intended to generate, for example, more or less white light containing different spectral colors. The light source can have, for example, an electric lamp, for example a halogen incandescent lamp, which can be operated, for example, with an electrical voltage of at most 50 V. However, the light source could also have an electric incandescent lamp with a halogen-free fill gas or a xenon high-pressure discharge lamp which can produce light with a continuous spectrum and some spectral lines superimposed on it. The light source could possibly have a spectral lamp for generating light with a pure line spectrum. However, this light should then preferably have some spectral lines of light that are distributed over the entire visible wavelength range. A non-electrical light source, for example designed to generate a flame, could possibly even be used.

The or each dispersion element preferably consists essentially of a clear, colorless material, which apart from at least one possibly present, at least partially shielding layer and / or of a light reflecting layer or other reflecting means, which is all in the visible wavelength range allows passing light to pass at least approximately without absorption. The or each dispersion element can, for example, consist of a mineral glass or a plastic glass, such as polycarbonate or polyacrylic glass.

During operation of the lighting device, at least some of the light generated by a light source and radiated through the dispersion element into the environment is spectrally broken down. In this case, a bundle of light can be emitted from each of the light exit surfaces located on opposite sides of the gap, which produces a clear spectrum. The surfaces of the dispersion element used to generate these light tufts should preferably be arranged and smooth in such a way that at least essentially all of the light rays resulting from the spectral decomposition and emitted from the dispersion element into the environment, contain light with different colors or different color ranges diverging directions and / or possibly approximately parallel to one another are radiated away from the dispersion element, so that they and their colors are separated from one another even at a large distance from the light exit surface of the dispersion element.

• die Figur 1 eine perspektivische Ansicht einer als Leuchte ausgebildeten, pyramidenförmigen Beleuchtungsvorrichtung,
• die Figur 2 einen Schnitt durch die in der Figur 1 gezeichneten Beleuchtungsvorrichtung,
• die Figur 3 eine perspektivische Ansicht einer anderen als Leuchte ausgebildeten Beleuchtungsvorrichtung,
• die Figur 4 einen Schnitt durch eine andere Beleuchtungsvorrichtung,
• die Figur 5 eine Seitenansicht von noch einer anderen, lampenartigen Beleuchtungsvorrichtung,
• die Figur 6 eine Frontansicht der in der Figur 5 ersichtlichen Beleuchtungsvorrichtung,
• die Figur 7 einen zum Spalt des Dispersionsorgans rechtwinkligen Schnitt durch eine als Leuchte ausgebildete Beleuchtungsvorrichtung mit einer ähnlichen Umrissform wie die in den Figuren 1 und 2 gezeichnete Beleuchtungsvorrichtung,
• die Figur 8 einen Schnitt durch den Spalt des Dispersionsorgans der in der Fig. 7 ersichtlichen Beleuchtungsvorrichtung,
• die Figur 9 eine Ansicht auf die untere Seite der in der Fig. 7 gezeichneten Beleuchtungsvorrichtung, wobei ein Teil des Supports weggebrochen ist,
• die Figur 10 einen Ausschnitt aus der Fig. 7 in grösserem Massstab und
• die Figur 11 eine Schrägansicht von einer länglichen Lichtquelle und einem trogförmigen Hohlspiegel einer Beleuchtungsvorrichtung.

The object of the invention will now be explained with reference to exemplary embodiments shown in the drawing. In the drawing shows

• 1 shows a perspective view of a pyramid-shaped lighting device designed as a luminaire,
• FIG. 2 shows a section through the lighting device shown in FIG. 1,
• FIG. 3 shows a perspective view of another lighting device designed as a luminaire,
• FIG. 4 shows a section through another lighting device,
• FIG. 5 shows a side view of yet another lamp-like lighting device,
• FIG. 6 shows a front view of the lighting device shown in FIG. 5,
• FIG. 7 shows a section at right angles to the gap of the dispersion element through an illumination device designed as a luminaire with an outline shape similar to that of the illumination device shown in FIGS. 1 and 2,
• FIG. 8 shows a section through the gap of the dispersion element of the lighting device shown in FIG. 7,
• FIG. 9 is a view of the lower side of the lighting device shown in FIG. 7, with part of the support broken away,
• 10 shows a section of FIG. 7 on a larger scale and
• FIG. 11 shows an oblique view of an elongated light source and a trough-shaped concave mirror of an illumination device.

The lighting device 1 shown in FIGS. 1 and 2 is generally symmetrical to a vertical axis 2 and designed as a lamp. This can be used, for example, as a floor lamp and placed on a support 3 formed, for example, by the floor of a building. The lighting device 1 has, for example, a bowl-shaped, opaque or translucent support 6, which rests freely on the support 3. However, the support 6 has, for example, three or another number of holes 6a distributed around the axis 2, so that it could be attached to the support 3 or instead to a wall or ceiling of a building or to a support of any kind. In the center of the support 6, a holder 7 with two contact sockets is attached. An artificial light source 9 has an electric halogen incandescent lamp which can be operated, for example, with a 12 V electrical voltage and whose base has two pin-shaped contact elements which are detachably inserted into the contact sockets of the holder 7. A concave mirror 10 is permanently attached to the base of the light source 9, which forms collimating means, surrounds the glass bulb of the incandescent lamp and consists, for example, of plastic with a metallized inner surface. The light source 9 is arranged on the axis 2 and the concave mirror 10 is generally rotationally symmetrical to the axis 2 and approximately parabolic in axial section, however, its reflecting inner surface is composed, for example, of a large number of small, flat surface sections. The holder 7 is connected by electrical conductors 11 to the output of a transformer 12 fastened to the support 6, the input of which can be connected to a connection of the electrical voltage network via an electrical cable 13.

The lighting device 1 has a cover 15, which generally has the outline shape of a pyramid symmetrical to the axis 2 with a square, namely square base area. The lower part of the cover 15 consists of a housing 16 with an opaque, truncated-parametric shell made of metal and / or plastic, the inner surface of which may be designed to be light reflecting. The top part of the cover 15 and the pyramid is formed by a translucent dispersion member 17 attached to the housing 16 and spaced from the light source 9 and the concave mirror 10. This has two one-piece dispersion bodies 18 which are separated from one another by a narrow, vertical gap 19 which runs parallel to two sides - ie base edges - of the pyramid through axis 2. The two dispersion bodies 18 are mirror-symmetrical to one another with respect to the central plane of the gap. On its side facing the light source 9 and the concave mirror 10, each dispersion body 18 has a base area 18a which is at a distance from the light source and the concave mirror. The base surfaces 18a of the two dispersion bodies 18 are, for example, flat and perpendicular to the axis 5. The two outer surfaces of the dispersion bodies 18 facing away from the gap 19 serve as light exit surfaces 18b. The outer surfaces of the two dispersion bodies adjoining the edges of the gap 19 are referred to below as side surfaces 18c. The flat surfaces 18b, 18c form an angle, for example, of approximately 45 ° with the base surfaces 18a, are smoothly connected at their lower edges to the outer surface of the housing 16, together form essentially - ie apart from the gap 19 - the outer or outer surface a pyramid and approach each other towards the top and away from the light source 9. In other words, the dispersion element 17, viewed alone, generally also forms a pyramid with a square, namely square, base area. The flat surfaces of the two dispersion bodies 18 which delimit the gap 19 and which are vertical to one another and parallel to the axis 2 are referred to as their interfaces 18d. The surfaces 18a, 18b, 18c, 18d are smooth and polished, for example. The two dispersion bodies 18 are clear, transparent and colorless and consist of mineral glass or plastic glass. In the latter case in particular, a flat, transparent heat shield 20 made of mineral glass, indicated by dash-dotted lines in FIG. 2, can be arranged between the light source 9 and the dispersion element 17 and attached to the support 6 or to the housing 16.

The housing 16 is provided in the vicinity of its lower edge on the inside with some tabs permanently connected to its wall, two of which are shown and designated 21. The cover 15 is detachably fastened to the support 6 by means of fastening means 22 having screws, for example. The support 6, the holder 7, the housing 16, the tabs 21 and the fastening means 22 together form holding means 23 for holding the artificial light source 9 and the dispersion element 17. Together with the support 6, the cover 16 delimits an interior containing the light source 9. and / or cavity 24. Accordingly, the cover 16 and the support 6 together form limiting means 25 which essentially counteract the light source 9 on all sides, namely apart from the gap 19 and some holes and openings in the support 6 and between its edge and the housing 16 delimit the surroundings of the lighting device.

The dispersion member 17 has on its side facing the light source - i.e. in the case of the base areas 18a - the dimension a. both at right angles and parallel to the gap 19. The length of the gap 19 is understood below to mean the maximum dimension measured perpendicular to the axis 2 and parallel to the light exit surfaces 18b, which is equal to the dimension a. The width b of the gap 19 is equal to the distance at which the two interfaces 18d are apart. The dimension measured parallel to axis 2 - i.e. the height - of the gap 19 is equal to the height c of the entire dispersion element. In FIG. 2, the distances d and e are also specified, which the mouth or light entry opening of the gap 19 facing the light source 9 from the edge of the concave mirror 10 facing it or from the luminous center of the light source 9, i.e. from the center of the filament formed by its filament.

The distance b forming the width b of the gap 19 Both interfaces 18d are expediently at most 15%, preferably at most 10% and for example 1% to 6% of the length of the gap and the dimension a of the dispersion body which is identical to this. Furthermore, the gap width b or the interface distance is preferably at most 20% of the dimension or height c of the dispersion element and gap. Furthermore, the distances d and e are preferably at least five times and even better at least ten times larger than the gap width b. The dimension a can be, for example, 60 mm to 120 mm. The gap width b is then expediently at most 18 mm, preferably at most 12 mm and for example 1 mm to 6 mm.

The light source 9 generates more or less white light during operation. This is collimated by the concave mirror 10 forming the collimating means in such a way that a light beam 27 is radiated against the dispersion element 17. A large part of the light from the light bundle 27, in particular at least the largest part of the light reflected by the concave mirror, lies within a conical envelope surface which is rotationally symmetrical with respect to the axis 2 and whose opening angle measured between diametrically opposed surface lines expediently is at most 20 °, preferably at most 15 ° and for example is approximately 8 ° to 12 ° or even only 4 ° to 8 °.

A part of the light generated by the light source 9 and partly reflected by the concave mirror 10 and radiated against the dispersion element 17 reaches the gap 19 and falls on the interfaces 18d. The gap 19 acts as a collimator for this light. The light impinging on the interfaces 18d is either parallel to these or forms only a small angle, for example at most about 15 ° or even only at most 10 °. At least a portion of the light striking the boundary surfaces 18d approximately penetrates into the light in question Interface-forming dispersion body 18 and thereafter, at its light exit surface 18b, again emerges from the latter into the surroundings of the lighting device 1. The light is refracted as it enters and exits and is spectrally broken down by dispersion, so that one of the two light exit surfaces 18b and a bundle of light 28 directed obliquely upward away from the gap 19 is formed, which contains red at the top, violet at the bottom and in between the remaining spectral colors of the generated light. The light bundles 28 form a relatively large angle with the axis 2, namely at least 30 ° and for example at least 45 °. If such a light bundle strikes, for example, at a certain minimum distance from the dispersion element on a vertical surface parallel to the slot 19 or on a horizontal surface, it produces an intense, stripe-shaped, slightly curved, rainbow-like for various observers, containing the various spectral colors clearly visible and beautiful-looking light spectrum.

The light source 9 also radiates light through the gap 19 into the surroundings of the lighting device. Of course, this light is not broken down spectrally.

At the base areas 18a, light penetrates into the dispersion bodies 18, which largely emerges from the dispersion bodies at the light exit areas 18b. At least a large part of this light is then radiated upwards so that it forms only a relatively small, for example less than 20 ° angle with the axis 2 and the central plane of the gap 19. With the side surfaces 18c, a little light is also radiated upwards out of the dispersion bodies. The light emerging steeply upward from the light exit surfaces 18b and above all the light emerging from the side surfaces 18c also becomes at least partially spectral disassembled. However, the colors of the light emerging from the side surfaces 18c and, in particular, the colors of the light emerging steeply upward from the light exit surfaces 18b are significantly paler than the colors generated by the light bundles 28. This is presumably due to the fact that several light spectra, partly superimposed on one another, are created, so that this light as a whole has more or less the original color at many points. In addition, the light that is radiated through the gap 19 and has not been broken down can still partially overlap the light radiated through the base areas 18a into the dispersion bodies and then steeply upwards out of them.

The concave mirror 10 can be a little translucent. In addition, the housing 16 and the dispersion element 17 can reflect a part of the light incident on them downwards. In particular, if the support 6 is transparent, some light can also escape into the environment between the lower edge of the housing 16 and the support 3.

During operation, the lighting device 1 emits a bundle of light 28 with differently colored light beams into the surroundings at each of the two light exit surfaces 18b, which generates a clear, bright, streak-shaped light spectrum when it hits at least one surface. The light radiated through the gap 19, the light radiated upwards out of the diffusion body 18, the light radiated out from the side surfaces 18c and the light possibly radiated out from under the housing 16 then give above and on the sides and below that of the light tufts 28 generated, strip-shaped light spectra at a distance from them also a certain, sometimes slightly multi-colored lighting. The lighting device 1 thus enables aesthetically attractive lighting of the surroundings and also has a pleasing shape. Since the lighting described with a single Light source, can be produced without a lens and without an excessively precise positioning requiring optical elements, the lighting device 1 is also inexpensive to manufacture.

The interior or cavity 24 has a coherent, free area, which is connected to the surroundings through the gap 19 at the top of the dispersion element. Furthermore, the free area of the interior 24 is connected to the surroundings through the openings present between the edge of the support 6 and the housing 16 and around the lower edge of the housing 16. In operation, the light source 9 and the transformer 12 generate heat. This can cause a convection flow, in which air flows from the environment down into the interior 24 and thereafter through this and the gap 19 upwards back into the environment. This convection flow can dissipate part of the heat generated during operation into the environment and thereby contribute to the fact that the various parts of the lighting device 1 and in particular the support 6, the housing 16 and the dispersion body 18 are not heated too much.

The lighting device 31 shown in FIG. 3 is also designed, for example, as a light to be placed on a support and has an axis 32 and a support 33 which detachably holds a light source 35, which in turn is firmly connected to a concave mirror 36. The lighting device 31 has a cover 37 which is detachably fastened to the support and has a housing 38 and a dispersion element 39 arranged at its upper end. This is in turn essentially pyramid-shaped and formed from two dispersion bodies 40 separated by a gap. The cover 37 forms, together with the support 33, holding and limiting means 41 which hold the light source 35 and the dispersion element 39 and delimit the light source from the surroundings.

The housing 38 differs from the housing 16 in that it has walls parallel to the axis 32 and forms a prism that is square in cross section. However, one could also provide that the housing tapers slightly upwards, so that the cover would then become obelisk. For the rest, the walls of the housing 38 can, for example, be made entirely or partially of tinted glass and accordingly be somewhat translucent or opaque and possibly have light-reflecting inner surfaces.

Unless otherwise specified above, the lighting device 31 can be designed the same or similar to the lighting device 31. Furthermore, the dispersion member 39 produces a similar light separation as the dispersion member 17. In addition, ventilation openings can still be present between the support 33 and the housing 38 and / or in the lower end section of the housing 38, so that a convection flow flowing through the housing can occur during operation.

The lighting device 51 shown in FIG. 4 is generally symmetrical with respect to an axis 52 and has a light source 53 which is of the same or similar design as the light source 9. This has a base 53a provided with pin-shaped contact elements 53b, to which a concave mirror 54 is permanently attached . At its end facing away from the base 53a, the latter has a collar 54a which projects radially outward to the axis 52. On its side facing away from the light source 53, a cover 55 is arranged. This has, for example, an opaque connecting element 56 which bears against the collar 54a and a dispersion element 57 which is permanently attached to its edge facing away from the collar 54a. This in turn has essentially the shape of a pyramid with a square, namely square base area and consists of two dispersion bodies 58 separated by a gap 59. The connecting element 56 encloses the connecting element 56 the axis 52 and connects the circular collar 54a to the square edge of the base of the dispersion element 61. The connecting element 55 is generally ring and / or sleeve and / or funnel-like. The inner surface of the connecting element 55 is, for example, parallel to the axis 52 in the section shown, while it widens, for example, in axial sections running through the corners of the base surface of the dispersion element from the collar 54a to the corners mentioned. However, the inner surface of the connecting element could also widen around the axis 52 from the collar 54a to the dispersion element. The connecting element 56 is detachably fastened to the collar 54a using, for example, a clamping ring and screws 61. The base 53 and the concave mirror 54, together with the cover 55, form limiting means 65, which enclose the light source 53 and essentially delimit the environment from all sides. However, the connecting element 56, to a certain extent forming a housing together with the concave mirror 54, may possibly also have ventilation openings in order to enable a convection flow flowing through it, the interior of the connecting element and the gap 59.

The base 53a serves as a support for the lighting device 51 and can be releasably connected for its use to a connection and holding element, for example consisting of a socket, by inserting the contact elements 53b into socket-like counter-contact elements of the connection and holding element and thereby bringing them into contact with the latter will. The connecting and holding member can, for example, be attached to a support of any kind and / or to a floor, wall or ceiling of a building. If the plug connection is not sufficiently stable, the lighting device 51 can additionally be supported and / or held with support and / or holding means 67, indicated schematically by dash-dotted lines, on the connecting and holding member or on any other suitable part will. Otherwise, the lighting device 51 produces a similar lighting effect as the lighting device 1.

The lighting device 71 shown in FIGS. 5 and 6 is designed in the manner of an electric lamp and consists, for example, entirely of parts which are permanently connected to one another and cannot be separated from one another without damage. The lighting device 71 is generally symmetrical about an axis 72 and has a base 73 with at least one cam 73a and two electrical contact elements 73b, 73c. The base serving as support for the lighting device is designed in such a way that it can be detachably connected to a lamp holder by means of a bayonet lock connection. This serves as a connecting and holding member and has mating contact elements which can be brought into contact with the contact elements 73b, 73c. However, the base could also have a thread or plug contact pins or some other connection means of any kind. The base 73 holds a light source 75, which has at least one wire coil connected to the contact elements 73b, 73c in an electrically conductive manner and possibly also a gas-tight glass bulb 75a, shown in dot-dash lines.

A cover 77 is attached to the base 73. This has a more or less pear-shaped glass bulb 78 which widens away from the base 73 and then tapers again. Its end section, which faces away from the base and tapers away from it, essentially has the shape of a pyramid with a square base, apart from the rounded transitions. This end section contains and / or forms a dispersion element 79. This has two glass dispersion bodies 80, each forming half of a pyramid, between which a gap 81 is present. This is limited by interfaces 80d of the two dispersion bodies 80. The gap 81 is on at least in the event that the light source 75 does not have its own glass bulb 75a its end facing away from the base 73 is sealed gas-tight against the environment. Depending on the manufacturing method of the lighting device 71, the two dispersion bodies 80 can form an integral body with the glass bulb 78 or at least be firmly and permanently connected to the glass bulb 78.

If the light source 75 has its own inner glass bulb 75a, this can contain a filling gas with a halogen additive. The region of the interior of the glass bulb 78 which surrounds the inner glass bulb 75a can then be evacuated, for example, or contain an inert gas filling or, in particular if it is not gas-tight to the surroundings, contain air. If the inner glass bulb 75a is not present, the interior of the glass bulb 78 can contain a fill gas with or without halogen addition.

The section of the glass bulb 78 located between the base 73 and the dispersion element 79 can, for example, be provided on its inside with a metallic reflection layer 83, which then forms a concave mirror which deviates somewhat from the ideal shape. In addition to or instead of the reflection layer 83, a concave mirror 85 similar to the concave mirror 10, indicated by dash-dotted lines in FIG. 5, may also be present. The reflection layer 83 and / or the concave mirror 85 forms or form reflection and collimation means with which the light generated by the light source 75 can be collimated and radiated against the dispersion element 79. Otherwise, the base 73 forms, together with the cover 77, partially transparent limiting means 87 which delimit the light source 75 on all sides from the surroundings of the lighting device 71.

For its use, the lighting device 71 can be releasably inserted into a lamp socket serving as a connecting and holding element, which can be connected to a transformer or to the "normal" AC voltage network, depending on the intended operating voltage of the light source 75. If the light source 75 is intended for operation with a low voltage, a transformer could possibly be installed in the base 73.

Unless otherwise stated above, the lighting device 71 can be designed in a similar manner and give similar lighting as the lighting device 1.

The lighting device 101, shown in FIGS. 7 to 10 and having a similar outline as the lighting device 1, defines an axis 102 and stands with a one-piece support 106 on a support 103. The support 106 is made of translucent, for example colorless, transparent plastic, and is bowl-shaped and has a circular support portion 106a. This has a central elevation 106b and three bulges distributed along its circumference and projecting downward and serving as feet 106c. The edge of the support section 106a is connected to a flat edge section 106e by an upwardly widening, conical section 106d. This has a substantially square edge and contains two mutually opposing, for example consisting of slots, holes 106f serving for fastening and a number of slot-shaped ventilation openings 106g. On the central elevation 106b of the support 106, a holder 107 is detachably fastened with fastening means 108 having screws. The light source 109 has a halogen lamp with a helical filament and a base, the plug contacts of which are detachably inserted in the contact sockets of the holder 107. On the base of the light source 9, a concave mirror 110 enclosing its glass jacket and filament is permanently attached. The holder 107 is connected by an electrical cable 111 to a transformer arranged, for example, outside the actual lighting device. On the base of the light source 109 and / or on a neck-shaped extension of the concave mirror 110 surrounding it, a cooling element 112 is fastened with a sheet metal disk, which projects in an axial projection over the concave mirror and is designed, for example, at least on its upper side facing the concave mirror, that it reflects light and heat rays.

A pyramid-shaped cover 115 has a housing 116 with a truncated pyramid-shaped, opaque, for example metallic shell and a translucent, essentially pyramid-shaped dispersion element 117 arranged at its upper end. This has two one-piece dispersion bodies 118 made of mineral glass or possibly plastic glass, which pass through a gap 119 are separated from each other. This defines a vertical central plane running through it and through the axis 102, which is parallel to two edges of the square formed by the pyramid-shaped dispersion element in the plan. The two dispersion elements are again mirror-symmetrical to one another with respect to the median plane mentioned. Each dispersion body 118 has a planar base surface 118a which is perpendicular to the axis 102 and faces the light source 109, on its side facing away from the gap 119 a planar, inclined light exit surface 118b and two planar, inclined side surfaces 118c which abut the edges of the gap 119.

As can be seen particularly clearly in FIG. 10, the interfaces 118d of the two dispersion bodies 118, which together delimit the gap 119, each have a first interface section 118e and a second interface section 118f. The first two interface sections 118e are flat and parallel to one another and to the axis 2. The second interface sections 118f are located on the side of the first interface sections 118e facing the light source and are also flat, but inclined slightly away from one another towards the light source. The interfaces 118d are therefore the same as the interfaces 18d in straight sections at right angles to the axis 102 or 2. In contrast, each interface 102 is slightly angled in an axial section perpendicular to it. The angle formed by the second interface sections 118f with the axis 102 is expediently at most 10 °, preferably at most 5 ° and for example at most 2 °, but has been drawn in FIGS. 7 and 10 for clarification with a rather exaggerated size. The light exit surface 118b of each dispersion element 118 therefore forms an angle both with the first and with the second interface section 118e or 118f of the dispersion element in question. For example, the angle between the light exit surface 118b and the first interface section 118e is approximately or exactly 45 °, while the angle between the light exit surface 118b and the second interface section 118f is a little smaller. The dimension of the second inclined interface sections 118f measured parallel to the axis 102 is smaller than the axial dimension of the first interface sections 118e and is preferably at most 30% and for example at most 20% of the axial dimension c of the entire dispersion element and the gap 119. The gap 119 has accordingly the formation of the interfaces 118d at its end facing the light source, a section widening toward the latter, the end of which facing the light source forms the light entry opening of the gap. The interfaces 118d or at least their second interface sections 118f should be as smooth as possible and are polished, for example, during the production of the dispersion bodies.

The two dispersion bodies 118 are at their top For example, the ends are a little flattened and / or rounded, so that the pyramid formed by the dispersion element does not have a sharp tip to reduce the risk of injury and damage. The dispersion bodies 118 are also provided at the outer edges of their base surfaces 118a with a groove 118g, into which the casing of the housing 116 protrudes and is firmly connected to the dispersion bodies there, for example by an adhesive 120.

The dispersion element 117 has the dimension a measured at the lower edges of the surfaces 118b, 118c of the dispersion body 118 at right angles to the axis 102 both parallel and at right angles to the central plane running through the gap 119. This is the maximum dimension of the dispersion element in the directions mentioned and also the maximum length of the gap. (The dimensions measured along the edges of the base areas 118a are a little smaller than a because of the grooves 118g.) The gap 119 has the width b at its light entry opening facing the light source. The width of the upper section of the gap 119 delimited by the first interface sections 118d is denoted by b ₁ in FIG. 10 and is slightly smaller than the width b. The relationships between the width b (and the width b ₁ ) and the dimensions or distances a, c, d, e can have, for example, the same limit values as were specified for the lighting device 1.

Arranged in the interior 125 of the housing between the concave mirror 110 and the dispersion element 117 is an aperture 121, which is spaced both from the concave mirror and from the dispersion element. This has a plate 122 made of mineral glass with at least essentially flat surfaces perpendicular to the axis 102. The plate 122 has a polygonal, namely square outline shape and is arranged such that one of its diagonals lies in the central plane of the gap 119. On the one, The top surface of the plate 122 has two opaque strips 123, which are parallel to the gap 119 and which, for example, consist of a glued or vapor-deposited metal layer. The two strips 123 are at a distance from one another and together delimit a translucent slot 124, the center line of which lies in the central plane of the gap 119. The width of the slot 124 is, for example, somewhat smaller than the width b of the light entry opening of the gap 119, but could also be approximately the same size as the width b or greater than this. At least the area of the plate 122 located in the area of the slot 124 is clear and transparent. The areas of the plate 122 located outside the two opaque strips 123 can, for example, also be clear and transparent. The areas of the glass plate 122 located outside of the strips 123 may, however, instead have a surface provided with a dot pattern and / or be somewhat milky in some other way, so that they are translucent but not clearly transparent, but only somewhat diffuse Allow light to pass through. The diaphragm 121 can additionally serve as a heat shield in order to shield the dispersion element against the heat generated by the light source.

On the inner surfaces of two opposing walls or sections of the casing of the housing 116, two strips 126 made of sheet metal and extending from the bottom upward are fastened, for example welded on. At the lower end, each strip 126 has an end section which is angled vertically downward and protrudes into the interior 125 and forms a tab 126a or 126b. The tabs 126a have a threaded bore into which screws serving as fastening means 127 for fastening the housing 116 to the support 106 are screwed, which penetrate the holes 106f of the support. The upper tabs 126b are each provided with a slot 126c shown in FIG. 10, into which a corner of the Plate 122 protrudes with at most small play. The strips 126 are otherwise designed such that the upper tabs 126b are resilient and can be temporarily spread apart from one another when the plate 122 is inserted.

The support 106 and the housing 116 form, together with other described parts, holding means 130 for holding the light source 109 and the dispersing element 117. Furthermore, the support 106, the housing 116 and the dispersing element 117 together form limiting means 131 which increase the number of the light source 109 and the interior 125 or less enclose on all sides and delimit from the environment. Incidentally, the light source 109 is arranged such that the axis of the filament formed by its filament is at least approximately parallel to the longitudinal directions of the gap 119 and the slot 124.

During operation of the lighting device 101, the light source 109 generates light, which is first collimated by the concave mirror 110, so that the latter emits a light beam 137 directed upwards against the diaphragm 121. Its inner part is then additionally collimated by the aperture 121, so that at least a large part of the light penetrating through the slot 124 of the aperture 121 reaches the gap 119. A portion of the light radiated into the gap 119 then penetrates through one of the boundary surfaces 118d into the dispersion body 118 forming it and emerges from the dispersion body again at its light exit surface 118b. This light is spectrally broken down, so that light bundles 138 are formed which correspond to the light bundles 28 generated by the lighting device 1.

The light tufts 28 and 138 emitted by the lighting devices 1 and 101 and containing different colored light beams become at least one large one Part of light formed which strikes regions of the interfaces 18d and 118d located in the vicinity of the light entry opening of the gap 19 and 119, respectively. The aperture 121 and the inclined, polished, second interface sections 118f of the lighting device 101 help to achieve particularly beautiful, multi-colored and bright spectra.

Light radiated past the opaque strip 124 can pass through the slot 124 of the diaphragm 121 and on the outside to the base areas 118a and penetrate through them into the dispersion bodies 118. This light is then radiated relatively steeply at least to a large extent analogously to the lighting device 1. The rasterization and / or clouding of the plate 122 which may be present outside the strips 123 results in the advantage that this light does not dazzle and that one cannot look directly into the light source. For the rest, instead of rastering or other clouding of the outer areas of the plate 123 or in addition to such a rastering or clouding, it is possible to provide the base areas 118a of the dispersion bodies 118 in such a way that they distribute the light penetrating them a little diffusely and / or steam.

During operation of the lighting device 101, a convection flow flowing from bottom to top through its interior 125 can form. Air from the surroundings around the lower edge of the casing of the housing 116 can enter the interior 125 through the ventilation openings 106g of the support 106 and through the openings between its edges and the casing 116 and out through the gap 119 stream.

Unless otherwise stated above, the lighting device 101 has similar properties to the lighting device 1.

FIG. 11 shows two brackets 157 to which an elongated, generally cylindrical light source 159, for example consisting of a halogen lamp, can be detachably attached. 11 also shows a trough-shaped concave mirror 160 which runs along the light source 159 and which, for example, can also be attached to the brackets 157, partially encloses the light source 159 in cross section and is parabolic in cross section, for example. The longitudinal axis 161 of the light source 159 can then run parallel to the light entry opening of the gap of a dispersion element (not shown) and lie in the central plane of the gap.

The lighting devices can be modified in other ways. For example, features of the various lighting devices previously described with reference to figures can be combined with one another.

Furthermore, the housings 16, 116 in the vicinity of the support 6 or 106 may also be provided with ventilation openings.

Furthermore, the dispersion element can have the shape of a pyramid with a rectangular base, the interfaces corresponding to the interfaces 18d, 118d then being able to run parallel to the longer sides of the rectangle. Furthermore, a pyramid-shaped dispersion element with a square or possibly rectangular base area could be divided into four dispersion bodies by interface pairs and slots forming a cross. These then have light exit surfaces on all four sides of the pyramid, through which light bundles with spectrally split light can be emitted into the surroundings.

Furthermore, the base areas of the dispersion element possibly instead of being inclined at right angles to the axis of the lighting device, so that the dispersion element has a depression on its side facing the light source or an increase tapering towards the light source. In addition, each base and / or interface and / or light exit surface can be slightly convex or concave in an axial section.

A dispersion element can also be provided in which the entire interfaces are inclined away from one another towards the light entry opening of the gap. The angle formed by each interface with the axis of the dispersion element and the central plane of the gap is then advantageously at most 10 °, preferably at most 5 ° and, for example, at most or approximately 2 °.

Furthermore, it is possible to provide a dispersion element, the slot of which extends away from the base areas only over part of the height of the dispersion element and, for example, forms a channel which is approximately U-shaped or V-shaped in cross section.

In addition, there is the possibility of providing a plurality of light sources or lamps and / or a plurality of dispersion elements, so that the lighting device can possibly emit a larger number of light bundles and spectrally decomposed light in different directions.

Claims (14)

1. Illumination apparatus having at least one dispersion member (17, 39, 57, 79, 117) which is transparent to light and having retaining means (23, 41, 130) for holding at least one artificial light source (9, 25, 35, 53, 75, 109, 159), the dispersion member (17, 39, 57, 79, 117) defining an axis (2, 32, 52, 72, 102) of symmetry and being formed for spectral separation of light produced by the light source (9, 25, 35, 53, 75, 109, 159) and radiated through the dispersion member (17, 39, 57, 79, 117), characterized in that the dispersion member (17, 39, 57, 79, 117) has boundary surfaces (18d, 80d, 118d) facing one another together bounding a gap (19, 59, 81, 119) and light emergence surfaces (18b, 118b) arranged on sides of the gap (19, 59, 81, 119) which face away from one another, that each boundary surface (18d, 80d, 118d) makes an angle with the light emergence surface (18b, 118b) present on the same side of the gap (19, 59, 81, 119), that the axis (2, 32, 52, 72, 102) passes through the gap (19, 59, 81, 119) and that the gap (19, 59, 81, 119) divides the dispersion member (17, 39, 57, 79, 117) at least almost completely.
2. Illumination apparatus according to Claim 1, characterized in that the intersecting lines of the light emergence surfaces (18b, 118b) and of the boundary surfaces (18d, 80d, 118d) adjacent to the gap (19, 59, 81, 119) are straight and parallel to one another in sections at right angles to the axis (2, 32, 52, 72, 102).
3. Illumination apparatus according to Claim 1 or 2, characterized in that the width (b) of the gap (19, 59, 81, 119) at its orifice facing the light source (9, 25, 35, 53, 75, 109, 159) is at most 15% and preferably at most 10% of that maximum dimension (a) of the dispersion member (17, 39, 57, 79, 117) which is measured at right angles to the gap (19, 59, 81, 119).
4. Illumination apparatus according to any of Claims 1 to 3, characterized in that the boundary surfaces (18d, 80d, 118d) are flat and parallel to a central plane passing through the gap (19, 59, 81, 119) and/or make an angle of at most 10° and preferably at most 5° with said central plane.
5. Illumination apparatus according to any of claims 1 to 4, characterized in that each boundary surface (118d) present on one side of the gap (119) has a first boundary surface section (118e) and a second boundary surface section (118f), that the two first boundary surface sections (118e) are flat and parallel to one another and that the two second boundary surface sections (118f) are inclined away from one another from the first boundary surface sections (118e) towards the opening of the gap (119), which opening is closer to the or each light source (109).
6. Illumination apparatus according to any of Claims 1 to 5, characterized in that the dispersion member (17, 39, 57, 79, 117) has, on its side facing the at least one light source (9, 25, 35, 53, 75, 109, 159), on each side of the gap (19, 59, 81, 119), boundary surfaces (18a, 118a) which make an angle with the light emergence surface (18b, 118b) present on the same side of the gap and also make an angle with the boundary surface (18d, 80d, 118d) present on the same side of the gap, the last-mentioned angle preferably being a least 60° and, for example, about 90°.
7. Illumination apparatus according to any of Claims 1 to 6, characterized in that the dispersion member (17, 39, 57, 79, 117) has side surfaces (18c, 118c) which, together with the light emergence surfaces (18b, 118b) form a lateral surface of a pyramid, which lateral surface tapers away from at least one light source (9, 25, 35, 53, 75, 109, 159).
8. Illumination apparatus according to any of Claims 1 to 7, characterized in that the or each light source (9, 25, 35, 53, 75, 109, 159) is formed for radiating light into the gap (19, 59, 81, 119) and, at the boundary surfaces (18d, 80d, 118d) adjacent to said gap, into the dispersion member (17, 39, 57, 79, 117).
9. Illumination apparatus according to any of Claims 1 to 8, characterized by collimation means for collimating the light radiated by the or each light source (9, 35, 53, 75, 109, 159) to the dispersion member (17, 39, 57, 79, 117).
10. Illumination apparatus according to Claim 9, characterized in that the collimation means have at least one concave mirror (10, 36, 54, 83, 85, 160).
11. Illumination apparatus according to Claim 9 or 10, characterized in that the collimation means have a diaphragm (121) which bounds a slit (124) which permits the passage of light and is parallel to the gap (119).
12. Illumination apparatus according to any of Claims 1 to 11, characterized in that it has a housing (16, 116) holding the dispersion member (17, 117) and enclosing the or each light source (9, 35, 109), that the gap (19, 119) connects the interior (24, 125) of the housing (16, 116) to the surrounding space adjacent thereto and that the interior (24, 125) is also connected to the surrounding space around at least one edge of the housing (16, 116), which edge faces away from the dispersion member (17, 117) and/or through at least one orifice.
13. Illumination apparatus according to any of Claims 1 to 12, characterized in that the dispersion member (17, 39, 57, 117) has two one-piece dispersion elements (18, 40, 58, 118) which are separated from one another by the gap (19, 59, 119) and preferably consist of a mineral glass.
14. Illumination apparatus according to any of Claims 1 to 13, characterized in that the dispersion member (17, 39, 57, 79, 117) consists of clear, colourless glass.

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