DE102008022888A1 - Lighting device comprising a light source surrounded by solid particles comprises a particle number density gradient in at least one direction away from the light source - Google Patents

Abstract

Lighting device comprising a light source that emits primary radiation when a voltage is applied and solid particles that surround the light source and interact with the primary radiation comprises a particle number density gradient in at least one direction away from the light source.

Description

• a) Leuchtmitteln, welche bei Spannungsbeaufschlagung eine Primärstrahlung emittieren;
• b) Feststoffpartikeln, welche die Leuchtmittel wenigstens bereichsweise umgeben und welche mit der Primärstrahlung Wechselwirken.

The invention relates to a lighting device with

• a) bulbs which emit a primary radiation when voltage is applied;
• b) solid particles which surround the bulbs at least partially and which interact with the primary radiation.

such Lighting devices are known from the market, with increasingly LEDs with a light-emitting semiconductor structure as the lighting means be used. As interacting with the primary radiation Solid particles are in particular known and known phosphor particles used which color materials having transparent materials and absorb radiation impinging upon them, taking them Radiation as secondary radiation emit at least at a different wavelength. In a suitable Choice of phosphor particles or phosphor particle mixtures Thus, the radiation emitted by the lamps in a radiation Radiation with different spectrum to be converted. An other species from with the primary radiation interacting solid particles can here, for example, reflection particles which reflect radiation impinging on them and can scatter.

Known Lighting devices of the type mentioned above often have a relatively small Beam angle between 120 ° and 160 ° for the of light given to them.

task The invention is a lighting device of the aforementioned To create a way in which the lighting effect improved and in particular the beam angle increases is.

• c) die Teilchenzahldichte der Partikel sich in zumindest einer Richtung von den Leuchtmitteln weg von einer ersten Teilchenzahldichte zu einer zweiten Teilchenzahldichte ändert.

This object is achieved in a lighting device of the type mentioned in that

• c) the particle number density of the particles changes in at least one direction away from the light sources away from a first particle number density to a second particle number density.

It has been found that in such a distribution of interacting with the primary radiation Particles around the bulbs around a kind of luminous structure achieved can be, which in turn light in almost all spatial directions emits. As a result, the emission angle of the lighting device can be increased. In addition, the luminosity of the lighting device is amplified.

The Particle density indicates the number of particles per volume.

advantageous Trainings are in the dependent claims specified.

It is advantageous if the particles phosphor particles, which primary radiation absorb and secondary radiation emit, and / or reflection particles, in particular barium sulfide, Barium sulphite, barium sulphate or titanium dioxide particles.

A Especially intensive lighting effect is achieved when the change the particle-particle density is a decrease, in particular, when the decrease of the particle-particle number density is uniform.

Yet the luminosity is better if a) a largest particle particle density is present in a first area, which the bulbs compared to others Areas closest is arranged adjacent and b) a smallest particle particle number density is in a second area, which is furthest from other areas the bulbs rests. In this case, the particle particle number density decreases So with increasing distance from the bulbs.

Quality Luminaire results are obtained when the largest particle particle number density 5 times to 10,000 times, preferably 10 times to 100 times, again preferably 10 times to 20 times, the smallest particle number density is.

there is it cheap if a) the largest particle particle number density between 500 and 20,000 particles per cubic centimeter, preferably between 1000 and 10,000 particles per cubic centimeter, and more preferably between 5000 and 10000 particles per cubic centimeter and b) the smallest particle number density between 2 and 5000 particles per cubic centimeter, preferably between 2 and 2500 particles per cubic centimeter and again preferably between 2 and 1000 particles per cubic centimeter.

manufacturing technology it is beneficial if the particles pass through a carrier medium in their position opposite the bulbs are held.

there it has proven to be particularly favorable if the carrier medium a silicone material, in particular an elastic silicone compound, or a resin, in particular an epoxy resin or a polyester resin, is.

Depending on the shape of the volume occupied by the carrier medium, different lighting effects can be achieved. As visually appealing with good lighting effect, it has been found that the carrier medium with the particles a cylindrical, conical or halbku gel-like volume or a volume which comprises a frusto-conical portion, which merges into a spherical portion occupies.

For the production the bulb is cheap, if the carrier medium arranged with the particles in a chamber of the lighting device is.

It is cheap, if the chamber wall at least partially made of glass, plastic, in particular an epoxy resin or a polyester resin.

If the lighting means comprise at least one semiconductor structure, which when voltage is emitted light, the lighting device produced with low energy consumption. Such bulbs are known in the form of LED called light-emitting diodes.

If the at least one light-emitting semiconductor structure upon application of voltage blue Light emitted, can be used on and known per se LED become. The particles are preferably both by phosphor particles formed from the blue radiation coming from the semiconductor structure is emitted, white light generate as well as formed by reflection particles, which the relay radiation to them.

alternative can the lighting means at least one red light semiconductor structure, at least one green light semiconductor structure and at least one blue light semiconductor structure. In this Case dispenses with phosphor particles and only reflection particles as with the primary radiation interacting particles are used.

below Be exemplary embodiments of Invention explained in more detail with reference to the drawings. In these show:

1 a partial section of a bulb lamp in which a loaded with phosphor and reflection particles carrier medium is arranged in a cylindrical chamber;

2 one of the 1 corresponding partial section of a second embodiment of a piston lamp, in which the chamber is conical;

3 one of the 1 corresponding partial section of a third embodiment of a piston lamp, in which the chamber is hemispherical;

4 one of the 1 corresponding partial section of a fourth embodiment of a piston lamp, in which the chamber has a frusto-conical portion, which merges into a spherical portion; and

5 a section of a light emitting diode whose interior is filled with a loaded with phosphor and reflection particles carrier medium.

In 1 is with 10 overall designates a bulb lamp, which has a standardized terminal socket 12 includes. The connection socket 12 may for example be designed as Edison screw base E27 or E11. All other standardized connection base, such as a bayonet socket, a socket, a glass pinch base or the like, may be provided.

From the connection areas of the connection socket 12 run in the interior of two lines 14 . 16 , which are shown with dashed lines. These lead out of the connection socket 12 to a voltage converter 18 inside of one of the connection sockets 12 carried transducer housing 20 is arranged. From the voltage converter 18 leads a first supply line 22 through a heat sink 24 to a first contact area 26 a light chip arrangement 28 , A second supply line 30 leads from the voltage transformer 18 through the heat sink 24 to a second contact area 32 the light chip arrangement 28 ,

The bulb lamp 10 includes a piston 34 of a translucent material, for example of glass or epoxy resin, which is connected to the heat sink 24 an interior 36 the bulb lamp 10 limited. The piston 34 the bulb lamp 10 may optionally fulfill the function of collection optics.

The light chip arrangement 28 includes four between the contact areas 26 and 32 the light chip arrangement 28 by means of thin bonding wires 38a . 38b . 38c . 38d and 38e series-connected semiconductor structures 40a . 40b . 40c and 40d , what a 1 are shown only schematically. These are on the ground 42 a depression 44 a carrier substrate 46 arranged. The carrier substrate 46 is made of sapphire crystal, which is also known as corundum (Al ₂ O ₃ glass).

Each semiconductor structure 40 includes three layers, which only in the semiconductor structure 40a are provided with reference numerals. A lower, on the carrier substrate 46 adjacent layer 48 is an n-type layer of n-GaN or n-InGaN, for example. A middle layer 50 is an MQW layer. MQW is the abbreviation for "Multiple Quantum Well". An MQW material is a superlattice which has an electronic band structure modified according to the superlattice structure and correspondingly emits light at other wavelengths advantage. By choosing the MQW layer, the spectrum of the semiconductor structure can be determined 40 influence emitted radiation. An upper layer 52 is made of a p-type III-V semiconductor material, such as. B. made of p-GaN.

With his the depression 44 radially surrounding edge region 54 carries the carrier substrate 46 a cylindrical housing 56 which leads to the semiconductor structures 40 towards and from the carrier substrate 46 distant side through an end wall 58 is closed. The housing 56 is made of plastic and can be clear or matt transparent. The housing 56 limited together with the carrier substrate 46 a chamber 60 which apart from the recess 44 in the carrier substrate 46 is also cylindrical.

The chamber 60 is with a carrier medium 62 filled, which is present in the embodiment described here in the form of an elastic silicone composition. In the silicone compound 62 are phosphor particles 64 and reflection particles 66 distributed through the silicone compound 62 in their position relative to the semiconductor structures 40 are held.

The semiconductor structures 40 Upon application of a voltage, ultraviolet light and blue light radiate in a wavelength range of 420 nm to 480 nm. Through the the semiconductor structures 40 enveloping silicone compound 62 with the phosphor particles 64 can be a white light bulb lamp 10 to be obtained. The phosphor particles 64 are made of color centered solid state materials. To the ultraviolet and blue primary radiation of Halbleiterstruk tures 40 convert to white light, are three types of phosphor particles 64 used, which partially absorb the ultraviolet and blue light and emit themselves in the yellow and red. If desired, additional phosphor particles 64 can be used, which emit themselves in the blue.

As material for the reflection particles 66 In particular, barium sulphide, barium sulphite, barium sulphate or titanium dioxide are suitable. Alternatively, as a material for the reflection particles 66 Scandium oxide or zinc sulfide and oxides of lanthanum and rare earth metals such. For example, ceria, neodymium oxide, samarium oxide, europium oxide, gadolinium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide or lutetium oxide can be used.

Through the reflection particles 66 becomes that of the semiconductor structures 40 emitted radiation within the silicone mass 62 forwarded.

The particle number density of the phosphor particles 64 and the reflection particle 66 changes towards the front wall 58 of the housing 56 that is, in one direction from the semiconductor structures 40 away, and take off in that direction. The largest particle number density of the phosphor particles 64 and the reflection particle 66 lies in a first layer 68 the silicone mass 62 which are the semiconductor structures 40 inside the chamber 60 is arranged closest. The smallest particle number density of the phosphor particles 64 and the reflection particle 66 lies a second layer 70 the silicone mass 62 which farthest from the semiconductor structures 40 abuts and on the inner surface of the end wall 58 of the housing 56 is applied.

Between the first shift 68 and the second layer 70 are arranged in capital letters designated intermediate layers A to K, wherein the particle number density of the phosphor particles 64 and the reflection particle 66 towards the front wall 58 of the housing 6 decreases evenly from one layer to the next. This is due to the number of phosphor particles shown in each layer 64 and reflection particles 66 illustrated. The border between two successive layers 68 , A to K and 70 is indicated by a dotted line.

Depending on the power with which the semiconductor structures 40 be operated and which via the voltage converter 18 can be specified, by the distribution of the phosphor particles 64 and the reflection particle 66 within the silicone mass 62 different light structures are generated with different outer contours, which can awaken the viewer, for example, the impression of a flame or a flare and which differs from the semiconductor structures 40 training starting.

In 1 are the outer contours of a spherical luminous structure 72a and a flame-like luminescent structure 72b indicated as dash-dotted lines stylized. A spherical luminous structure 72a forms at a lower operating voltage of the bulb lamp 10 from, whereas the flame-like lighting structure 72b at a higher operating voltage of the bulb lamp 10 occurs. At a suitably high operating voltage, the whole in the chamber largely lights up 60 silicone compound 62 ; then the luminous structure has the shape of a cylinder.

In the production of the bulb lamp 10 can the chamber 60 layer by layer with less liquid silicone oil are filled, which previously with a hardener and necessary for the particular desired particle number density amount of phosphor particles 64 and reflection particles 66 was mixed. The silicone oil then cures in a manner known per se to form an elastic silicone compound 62 out. After the curing of a first layer, a further layer of silicone material can be correspondingly provided 62 with phosphor particles 64 and reflection particles 66 be made on the first layer.

So that the chamber 60 can be filled in this way, for example, a filler neck can be provided which is removed or closed when the chamber 60 was completely filled.

It has proven to be practical if the particle number density of the phosphor particles 64 and the reflection particle 66 each chosen so that the cured silicone composition 62 appears slightly milky to yellowish to the human eye. This is achieved, among other things, when the largest particle number density of the phosphor particles 64 and the reflection particle 66 in each case from 5 times to 10,000 times, preferably from 10 times to 100 times, more preferably from 10 times to 20 times, the smallest particle number density of the phosphor particles 64 or the reflection particle 66 is.

In practice, the largest particle number density of the phosphor particles 64 and the reflection particle 66 in each case between 500 and 20,000 particles per cubic centimeter, preferably between 1,000 and 10,000 particles per cubic centimeter, and more preferably between 5,000 and 10,000 particles per cubic centimeter, whereas the smallest particle number density of the phosphor particles 64 and the reflection particle 66 in each case values between 2 and 5000 particles per cubic centimeter, preferably between 2 and 2500 particles per cubic centimeter, and more preferably between 2 and 1000 particles per cubic centimeter.

In a modification, not only blue light semiconductor structures become 40 but is white light by a combination of at least one red light semiconductor structure 40a , a green light semiconductor structure 40b and a blue light semiconductor structure 40c won, with no fourth semiconductor structure 40d is used. In this case, the phosphor particles can 64 in the silicone mass 62 be omitted and only reflection particles 66 with the corresponding particle number densities in the silicone composition 62 be distributed.

In a further modification, the carrier medium 62 be of a translucent in the cured state resin, for example of an epoxy resin or a polyester resin. In this case, the layers can 68 , A to K and 70 of the carrier medium 62 can be obtained in each case by curing of layers of a liquid applied resin, which was added to a curing agent, as it is known per se, and which previously with the necessary particle density for each desired amount of phosphor particles 64 and reflection particles 66 was mixed.

In a further modification, the carrier medium 62 that of the chamber 60 occupy corresponding volume, without this of the housing 56 is limited. For this purpose, the housing after complete curing of the support medium 62 removed and thus serves as a mold for the carrier medium 62 ,

In the 2 . 3 and 4 are other embodiments of the bulb lamp 10 shown, which differ from the in 1 shown bulb lamp 10 only by the shape of the chamber 60 mitbegrenzenden housing 56 differ. The individual layers of the carrier medium 62 are in the 2 . 3 and 4 for the sake of clarity, not specifically provided with reference numerals, also the layer boundary suggestive dotted lines have been omitted. Unless otherwise explained below, the above applies to the bulb lamp 10 to 1 Said accordingly for the piston lamps 10 after the 2 to 4 ,

At the bulb lamp 10 in 2 is in place of the housing 56 a conical housing 74 provided so that the carrier medium 62 a conical volume within one apart from the well 44 in the carrier substrate 46 cone-shaped chamber 76 occupies. The conical housing 74 is arranged so that its tip from the semiconductor structures 40 dista. With a suitable operating voltage, the luminous structure formed here can thus have the shape of a cone.

At the bulb lamp 10 in 3 is in place of the housing 56 a hemispherical housing 78 provided so that the carrier medium 62 a hemispherical volume within one apart from the well 44 in the carrier substrate 46 hemispherical chamber 80 occupies. The hemispherical case 78 is arranged so that its curvature from the semiconductor structures 40 dista. With a suitable operating voltage, the luminous structure formed here can thus have the shape of a hemisphere.

At the bulb lamp 10 in 3 is in place of the housing 56 a housing 82 provided which has a frustoconical section 82a includes, in a spherical section 82b passes. The housing 82 sits with his frustoconical section 82a on the edge area 54 of the carrier substrate 46 , The carrier medium 62 thus takes a corresponding volume within a chamber 84 one that apart from the recess 44 in the carrier substrate 46 a frustoconical Be rich and has a hemispherical area. With a suitable operating voltage, the luminous structure formed here can thus have a corresponding shape.

In 5 is a light emitting diode 86 shown a spherical transparent housing 88 with a removable cover part 88a includes. The housing 88 delimits a chamber 90 in which a the carrier substrate 46 corresponding carrier substrate 92 is arranged, which is a semiconductor element 94 carries that the semiconductor elements 40 equivalent. The carrier substrate 92 comes from a first terminal 96 held, extending through the lid part 88a extends outwardly and immovably with the lid part 88a connected is. A second connection terminal 98 also extends through the lid part 88a of the housing 88 with which she is firmly connected, out of the chamber 90 the LED 86 outward. The housing 88 fulfilled at the light emitting diode 86 the function of the chamber 60 at the bulb lamps 10 after the 1 to 4 ,

The semiconductor element 94 is over bonding wires 100 and 102 with the terminals 96 . 98 connected and can be applied via this with an operating voltage.

The chamber 90 the LED 86 is with the carrier medium 62 filled, in which phosphor particles 64 and reflection particles 66 are distributed as it is above in the context of the bulb lamps 10 after the 1 to 4 was explained.

If as a carrier medium 62 an elastic silicone compound is to be used, in the manufacture of the light emitting diode 86 the housing 88 with removed cover part 88a layer by layer with less liquid silicone oil are filled, which previously with a hardener and necessary for the particular desired Teilchenzahldichte amount of phosphor particles 64 and reflection particles 66 was mixed. The silicone oil then cures in a manner known per se to form an elastic silicone compound 62 out. After the curing of a first layer, a further layer of silicone material can be correspondingly provided 62 with phosphor particles 64 and reflection particles 66 be made on the first layer. This can be the case 88 have a filler neck, which is not shown here specifically.

With the light-emitting diode 86 Light can be emitted over a range of substantially 360 °.

In practice, the, if appropriate averaged, diameter of the chambers 60 . 76 . 80 . 84 at the bulb lamps 10 after the 1 to 4 and the chamber 90 at the light emitting diode 86 for example, between 1 mm and 300 mm, preferably between 1 mm and 200 mm, and more preferably between 3 mm and 30 mm. The height of the chamber 60 . 76 . 80 . 84 or 90 is in practice, starting from the semiconductor structures 40 or the semiconductor structure 94 for example, between 3 mm and 300 mm, preferably between 3 mm and 150 mm, and more preferably between 10 mm and 60 mm.

Claims (15)

Lighting device with a) bulbs ( 40 ; 94 ) which emit a primary radiation when voltage is applied; b) solid particles ( 64 . 66 ), which the bulbs ( 40 ; 94 surrounded at least in regions and which interact with the primary radiation; characterized in that c) (the number density of the particles 64 . 66 ) in at least one direction of the bulbs ( 40 ; 94 ) changes from a first particle number density to a second particle number density. Lighting device according to claim 1, characterized in that the particles ( 64 . 66 ) Phosphor particles ( 64 ), which absorb primary radiation and emit secondary radiation, and / or reflection particles ( 66 ), in particular barium sulphide, barium sulphite, barium sulphate or titanium dioxide particles. Lighting device according to claim 2, characterized in that that change the particle particle number density is a decrease. Lighting device according to claim 3, characterized in that that the decrease of the particle-particle number density is uniform. Lighting device according to one of claims 2 to 4, characterized in that a) a largest particle particle number density in a first area ( 68 ) is present, which the bulbs ( 40 ; 94 ) is located next to other areas closest to each other; b) a smallest particle number density in a second region ( 70 ), which is furthest from the light sources ( 40 ; 94 ). Lighting device according to claim 5, characterized in that that the largest particle particle number density 5 times to 10,000 times, preferably 10 times to 100 times, again preferably 10 times to 20 times, the smallest particle number density is. Lighting device according to claim 5 or 6, characterized in that a) the largest particle particle density between 500 and 20,000 particles per cubic centimeter, preferably between 1,000 and 10,000 particles per cubic centimeter, and more preferably between 5,000 and 10,000 particles per cubic centimeter; b) the smallest particle number density is between 2 and 5000 particles per cubic centimeter, preferably between 2 and 2500 particles per cubic centimeter, and more preferably between 2 and 1000 particles per cubic centimeter. Lighting device according to one of claims 2 to 7, characterized in that the particles ( 64 . 66 ) by a carrier medium ( 62 ) in their position opposite the bulbs ( 40 ; 94 ) are held. Lighting device according to claim 8, characterized in that the carrier medium ( 62 ) is a silicone material, in particular an elastic silicone composition, or a resin, in particular an epoxy resin or a polyester resin. Lighting device according to claim 8 or 9, characterized in that the carrier medium ( 62 ) with the particles ( 64 . 66 ) assumes a cylindrical, conical or hemispherical volume or volume which includes a frusto-conical portion which merges into a spherical portion. Lighting device according to one of claims 8 to 10, characterized in that the carrier medium ( 62 ) with the particles ( 64 . 66 ) in a chamber ( 60 ; 76 ; 80 ; 84 ; 90 ) of the lighting device ( 10 ; 86 ) is arranged. Lighting device according to claim 11, characterized in that that the chamber wall at least partially made of glass, plastic, in particular an epoxy resin or a polyester resin. Lighting device according to one of claims 1 to 12, characterized in that the lighting means ( 40 ; 94 ) at least one semiconductor structure ( 40 ; 94 ) which emits light when exposed to voltage. Lighting device according to claim 13, characterized in that the at least one light-emitting semiconductor structure ( 40 ; 94 ) emits blue light when exposed to voltage. Lighting device according to claim 13, characterized in that the lighting means ( 40 ) at least one red light semiconductor structure ( 40a ), at least one green light semiconductor structure ( 40b ) and at least one blue light semiconductor structure ( 40c ).