DE202007008258U1 - LED bulbs - Google Patents

Abstract

LED illuminant (1) having
- a base (2) with power connections (8a, 8b),
At least one white LED (7a),
At least one monochromatic LED (7b),
wherein the light emitted from the LED illuminant (1) has a color temperature of at most 6,500 K and a color rendering index of at least 80 Ra.

Description

The The present invention relates to a light source with light-emitting diodes (LEDs), which may be designed in particular as an "LED light bulb", i.e. to replace conventional lightbulbs can be dimensioned.

conventional lightbulbs consist of a mounting base including the electrical power supply and a glass bulb containing a filament and its holder in front of the outside environment shields.

Of the Filament - the electric Ladder - gets through Current flow heated so much that it glows, i. thermal radiation emitted. The absorbed electrical energy is partly in Shape emitted visible light. But such incandescent lamps consume a lot Electricity and the filament has a rather limited lifespan.

A bulb-shaped LED light is out of the JP 2006 156 187 known. A plurality of LEDs is arranged on a printed circuit board. The LEDs emit blue in the near UV range or in the wavelength range of the color. A phosphor layer or phosphor layer causes the emitted wavelengths to shift such that "white" light is generated from the UV or blue light by mixing with converted light.

"White" means that possibly with gaps in the essentially the whole visible spectrum is covered.

Problematic Here is the fact that the resulting white light an unsatisfactory color rendering index of less than 80 Ra having. Furthermore, it has to be complained that the efficiency of such a generated white light is much smaller (around 25%) is like that of a cool white light.

This LED bulb is therefore not suitable for warm white light provide. Also not suitable are RGB LEDs, as these LEDs unacceptable color shadows and high color tolerances.

It is therefore an object of the present invention, an LED light source of the above called kind, to create a warm white light with good Ra value can generate.

According to one In the first aspect of the invention, an LED illuminant has a base with mains connections, at least a white one LED (i.e., a monochromatic LED with color conversion layer), and at least one monochromatic LED. That of the LED bulb emitted light has a color temperature of at most 6 500 K and a color rendering index of at least 80 Ra.

According to one Another aspect of the invention, an LED illuminant has a socket with power connections, at least a white one LED, and at least one monochromatic LED on. That of the LED bulb emitted light is a warm white light with a color rendering index of at least 80 Ra.

The LEDs can arranged on a LED module with the chip-on-board technology (CoB) be.

The LED module can then be made of ceramic or metal. Thus, points the LED module has an optimal thermal conductivity.

When Base material for The LED module can also be an electrically insulating substrate can be used such as impregnated with epoxy resin glass fiber mats (Material identifier FR4). Made of epoxy resin and fiberglass fabric FR4 material preferably has via (vias).

The Shape of the socket and the positioning of the power connections are preferably identical in construction to a normalized incandescent lamp, a standardized halogen bulb or fluorescent lamp, in particular compact fluorescent lamp.

at the same power supply can Luminous efficacy of the LED lamp and that of a normalized incandescent lamp, a normalized halogen bulb or a normalized fluorescent lamp, in particular compact Fluorescent lamp, the same or similar be.

Consequently it is achieved that the LED lighting device according to the invention a normalized light bulb, a normalized halogen bulb or a normalized fluorescent lamp, in particular a compact fluorescent lamp, can replace. Such normalized lamps can in particular after a defined by the standards E ** (in particular E27), G *, GU * or T * be. The LED lighting device according to the invention can So a light bulb successfully replace one of these standards.

The LED bulbs can continue cooling fins for heat dissipation have, wherein the cooling fins then preferably can be arranged around the LED driver, the the electronics for controlled or regulated power supply represents the LEDs.

The monochromatic LED can be one in the red range (especially in the Range 600 to 650 nm) emitting LED.

The Monochromatic LED, or the monochromatic LEDs, can each commercial LED with an emission wavelength be in the range 490 to 650 nm. In this wavelength range Most phosphors are not significantly stimulated and the light the monochromatic LEDs can be the phosphorus containing element shine through with low losses. A preferred design summarizes all LEDs, the blue ones to produce the white light and the extra ones monochromatic LEDs in close packing under a phosphor element together.

The LEDs can be arranged so close to each other that a homogeneous light beam or a homogeneous light beam is generated. Another improvement of homogeneity is due to the above-described arrangement of all LEDs under a phosphor element reached.

In a preferred embodiment the application of the phosphor element takes place by means of Dispenstechnik in liquid form. For this purpose, a dam is previously applied as a boundary.

One at the mains connections Connected LED driver can be used to operate the LEDs within of the LED bulb be arranged.

The LED bulbs may further comprise a glass bulb with at least a glare-free area based on a micro or nanostructure, in particular a Fresnel structure.

Farther the LED illuminant can have at least one optical filter, which is designed to selectively and selectively a share of from the LED bulb forwarding or filtering the emitted light.

Further Features and advantages of the invention will become apparent upon reading the following description of preferred embodiments, referring to the drawings To refer to.

1 shows an LED lamp according to the present invention,

2 shows an embodiment of an LED module with LEDs according to the present invention,

3 shows a further embodiment of an LED module with LEDs according to the present invention,

4 shows the distribution of light with an in 2 or 3 shown LED module is achieved

5 shows a side view of an LED distribution according to another embodiment of the present invention,

6 shows a plan view of in 5 shown embodiment,

7 shows the distribution of the light according to the in 5 and 6 shown embodiment.

In the 1 is an LED bulb 1 according to an embodiment of the present invention.

The LED bulb 1 according to this embodiment points to a pedestal 2 , a central area 3 with the control electronics, at least one printed circuit board 4 with LEDs (light emitting diodes) 7a . 7b . 7c , a glass flask 5 , as well as lateral slats 6 ,

The base 2 , Connection socket or mounting base extends along an X-axis and is used to attach the LED bulb 1 as well as the electrical power supply via mains connections 8a . 8b ,

The base 2 preferably has standardized shape and dimensions, which are commonly used eg in filament lamps or halogen incandescent lamps. The fastening of the pedestal 2 can be realized for example by means of a known in the prior art Edison or screw thread or a bayonet lock.

The first power connection 8a , also called external contact, is on the cylindrical part of the base 2 or the lamp socket between insulation parts 9 arranged and preferably extends over the entire circumference of the base 2 ,

At the foot of the pedestal 2 according to the X-axis is the second mains connection 8b which is also called foot contact.

With the power connections 8a . 8b via appropriate lines 10a . 10b connected to the central area extends 3 of the LED bulb 1 essentially over the X-axis. The central area 3 consists of the entire control electronics for the LEDs 7a . 7b . 7c and is preferably in a housing 11 encapsulated to protect this electronics from outside influences. Likewise, by this housing 11 a user shielded from the electronics and protected.

In the case 11 is preferably a supply switching power supply such as an AC / DC converter 12 provided to those of the lines 10a . 10b to deliver the delivered voltage. The AC / DC converter 12 thus generates from the at the mains connections 8a . 8b applied AC voltage, a DC voltage for operating the LEDs 7a . 7b . 7c ,

Alternatively, the power supply switching power supply can also be an AC / AC converter or a DC / DC converter, depending on which mains supply the LED lighting means 1 should be trained and how the LEDs 7a . 7b . 7c be supplied or controlled.

One with the from AC / DC converter 12 generated DC voltage supplied LED driver module is adapted to control the total current for the LEDs or regulate. This therefore represents a constant current source for operating the preferably series-connected LEDs 7a . 7b . 7c , This constant current source in particular of transistors 14 , Diodes 15 and control resistors 16 can exist.

The LEDs powered by this constant current source 7a . 7b . 7c are as said preferably connected in series. Alternatively, a plurality of LED branches can be provided, in which case preferably different constant current sources control or supply the various branches.

The on the LED module 17 attached LEDs have different emission colors. At least one LED 7a should be a white LED. Furthermore, at least one monochromatic LED 7b provided, for example, the red light (preferably in the range 600 to 650 nm) emitted.

The LED lighting can then be a phosphor layer or a phosphor element contain, with all the LEDs, the blue to stimulate the phosphor and the additional (s) monochromatic LED (s) are arranged under the phosphor element. Thus, you can other spectra are generated.

That of the LED bulbs 1 Total light generated results from that of the individual LEDs 7a . 7b . 7c emitted light and is according to the invention a warm white light having a color rendering index of at least 80 Ra and / or a color temperature of at most 6500 K.

It is useful if the LEDs 7a . 7b . 7c in chip-on-board or flip-chip technology on the LED module 17 are arranged. These technologies allow assembly of the LED chips at a very close distance. Preferably, the distance is a maximum of 0.4 mm. As a result, good color mixing of the emission of the individual chips can be ensured.

The LEDs 7a . 7b . 7c are preferably arranged so close to each other that a good color mixing can be ensured.

By suitable choice of materials, the chip-on-board technology can achieve excellent thermal conductivity in the range of, in particular, 15 to 80 W / K m. Because of this, the LEDs can 7a . 7b . 7c operate at the same operating temperatures with higher operating currents.

The Materials for a chip-on-board module are preferably made of ceramic, metal or FR4 (epoxy + glass fiber fabric) with metal vias (Vias), so that an optimal thermal conductivity can be achieved.

The LED module 17 itself is on a plate 18 arranged with good thermal conductivity. A high thermal conductivity and thus a fast heat transfer are achieved with copper or aluminum, so that the plate 18 preferably consists of one of these metals.

According to another embodiment, a plurality of LED modules 7 arranged side by side on the plate.

An insulating layer 19 , which is thermally conductive, separates the LED module for safety reasons 17 from the plate 18 , This isolation layer 19 For example, is a thin ceramic plate.

According to alternative embodiments may be applied to this insulating layer 19 be omitted, for example, when the control electronics 3 and / or the further electronics of the LED light source 1 is galvanically isolated.

The LEDs 7a . 7b . 7c or the LED module 17 are on the plate 18 attached in a known manner, preferably either glued or screwed on it to achieve a good thermal connection.

The control electronics 3 is from a pipe 20 or framed by a sleeve, wherein the tube 20 preferably as a housing 11 for the control electronics 3 serves. The pipe 20 extends along the X-axis of one of the insulation parts 9 right down to the plate 18 and is preferably made of copper or aluminum.

At the connection between the pipe 20 and the plate 18 Care should be taken that a sufficient thermal conductivity is achieved. Accordingly, the pipe 20 and the plate 18 held together by pressing, screwing or soldering and connected. The of the control electronics 3 generated heat can thus through this connection to the plate 18 be directed.

The plate 18 has an opening 21 on, causing lines the control electronics 3 with the LEDs 7a . 7b . 7c or with the LED module 17 combines. For safety reasons, these lines preferably have an additional insulating sleeve (not shown).

On the plate 18 is a dome-shaped glass bulb 5 attached as a transparent protective layer for the LEDs 7a . 7b . 7c and possibly also formed as a light-collecting element for increasing the light intensity.

Furthermore, according to the invention, the glass bulb 5 as well as the pipe 20 , the plate 18 and the slats 6 for cooling the LED bulb 1 serve, even if the thermal conductivity of the glass bulb 5 less than, for example, that of the plate 18 should fail.

Will the glass bulb 5 not made of glass but made of transparent plastic, so it can hardly serve for heat dissipation. The material glass is therefore to be preferred over plastic, since the thermal conductivity of the glass is significantly higher than that of the plastic.

The glass bulb 5 is so on the plate 18 mounted and attached that heat to the glass bulb 5 can actually be directed. This is ensured, for example, by a thermally conductive adhesive.

On the external surface of the pipe 20 are cooling fins or cooling fins 6 educated. These cooling fins 6 extend substantially perpendicular to the X-axis and the tube 20 parallel to the plate 18 , The individual cooling fins 6 can be like a disk over the entire circumference of the LED bulb 1 extend. According to an alternative embodiment, the cooling fins 6 formed as a grid and on the pipe 20 arranged.

The cooling fins 6 are formed to the heat dissipation surface of the tube 20 and the plate 18 to enlarge. The cooling fins 6 are formed as a straight shape and preferably welded or soldered parallel to each other on the tube, which provides good thermal conductivity. Alternatively, the cooling fins 6 for example, be wavy.

It should be noted that the inventive design of the LED bulb 1 a high heat dissipation from the LEDs 7a . 7b . 7c as well as from the control electronics 3 guaranteed.

Be the LEDs 7a . 7b . 7c namely of the control electronics 3 brought to light, it creates a certain warmth. This heat becomes the cooling fins 6 made of copper or aluminum, through the plate 18 and the pipe 20 directed.

2 shows a further embodiment of an LED module according to the invention 30 with LEDs.

A total of four LEDs are on the LED module 30 attached: a red LED 31 is from three white LEDs 32 framed. The LED module 30 is flat and rectangular or square with a side length of preferably around 20 mm.

The red LED 31 is located in the middle of the surface of the LED module 30 and also in the middle of one through the three white LEDs 32 defined triangle.

In addition to the four LEDs, the LED module points 30 of the 2 two supply connections 33 . 34 which is used to control and supply the LEDs with the control electronics 3 are connected.

In 3 is another embodiment of an LED module according to the invention 35 shown.

This LED module 35 is as well as in 2 flat and rectangular or square with this time a side length of preferably about 27 mm.

The increased area of the LED module 35 makes it possible to arrange additional LEDs on it. The total of eight LEDs belong to two different groups or varieties: two LEDs 36 emit in the red region (preferably in the range 600 to 650 nm) and the other six are white LEDs 37 ,

The red LEDs 36 are in the middle of the LED module 35 attached, pretty close each other. The white LEDs 37 are around the red LEDs 36 evenly distributed in a kind of circle.

Thus, the invention generally proposes, in the middle of the LED module, a certain number X of monochromatic LEDs of a type-in 2 and 3 these are red LEDs - and a number Y of white LEDs on the rest of the surface. The number X is preferably less than Y.

The pattern constituting the monochromatic LEDs and the white LEDs is preferably symmetrical to the center of the LED module. Furthermore, the white LEDs can form a circle or al ternatively even several circles with different diameters.

Important is it the case that the white ones LEDs which are monochromatic e.g. frame or surround red LEDs.

The light distribution that is achieved by this is in 4 shown. The light is coming from the LEDs in all directions - just from the plate 18 limited - preferably uniformly emitted.

An alternative distribution of the LEDs is still in 5 and 6 shown. The corresponding light emittance is in 7 shown.

5 is a side view and 6 a plan view of an LED bulb with a total of three LED modules 40 . 41 . 42 , Each LED module has two supply connections 43 . 44 , a white LED 45 and a monochromatic, for example, red LED 46 ,

Alternatively, each LED module could also have multiple white LEDs 45 and / or several monochromatic eg red LEDs 46 exhibit. Note, however, that all LED modules are the same, ie the same number and distribution of LEDs 45 . 46 to have.

The three LED modules 40 . 41 . 42 are not right on the plate 18 arranged but each on one side of one on the plate 18 attached carrier 47 or tetrahedrons.

By definition, this tetrahedron consists of four congruent triangular sides, with one of these sides with the plate 18 connected and the other three each record an LED module.

The carrier 47 consists of a thermally conductive material such as copper or aluminum and thus contributes to heat dissipation.

Other forms of the carrier 47 are of course conceivable, for example, more polyhedron forms. The more pages the carrier 47 has, the more LED modules and thus LEDs can find space on it and the more homogeneous is the emitted light from the LED bulb.

To ensure homogeneity of the generated light, the arrangement of the LEDs on the LED modules is periodic. So borders eg in 6 a red LED 46 to the white LED 45 of the same LED module 42 and to the white LED of the adjacent LED module 41 , but not to the red LED 46 of the adjacent LED module 41 ,

As in 7 Shown, the light from the LED bulb is also behind the through the plate 18 defined level broadcast.

This is due to the fact that the LED modules 40 . 41 . 42 not directly on the plate in this embodiment 18 or on the insulation layer 19 are arranged, but at a certain distance from the plate 18 on the carrier 47 are attached.

Claims (15)

LED bulbs ( 1 ) - a pedestal ( 2 ) with power connections ( 8a . 8b ), - at least one white LED ( 7a ), - at least one monochromatic LED ( 7b ), whereby that of the LED illuminant ( 1 ) has a color temperature of at most 6,500 K and a color rendering index of at least 80 Ra. LED bulbs ( 1 ) - a pedestal ( 2 ) with power connections ( 8a . 8b ), - at least one white LED ( 7a ), - at least one monochromatic LED ( 7b ), whereas that of the LED illuminant ( 1 ) emitted light is a warm white light with a color rendering index of at least 80 Ra. LED illuminant according to claim 1 or 2, wherein the LEDs ( 7a . 7b . 7c ) with the chip-on-board technology on an LED module ( 17 ) are arranged. LED lighting device according to claim 3, wherein the LED module ( 17 ) made of ceramic, metal or FR4, ie an epoxy resin with glass fiber fabric, with vias. LED illuminant according to one of claims 1 to 4, wherein the shape of the base ( 2 ) and the positioning of the network connections ( 8a . 8b ) as in a normalized incandescent lamp, a normalized halogen incandescent lamp or a normalized fluorescent lamp, in particular compact fluorescent lamp, are. LED lighting device according to one of claims 1 to 5, wherein at the same power supply, the light output of LED bulbs and those of a normalized incandescent lamp, normalized halogen bulb or normalized fluorescent lamp, especially compact fluorescent lamp, are the same or similar. LED lighting device according to one of claims 1 to 6, comprising cooling fins ( 6 ) for heat dissipation. LED lighting device according to claim 7, wherein the cooling ribs ( 6 ) around the LED driver ( 13 ) are arranged. LED lighting device according to one of claims 1 to 8, with all the LEDs used, the blue to stimulate the phosphor and the additional (s) monochromatic LED (s) arranged under a phosphor element are. LED illuminant according to one of claims 1 to 8, wherein the monochromatic LED ( 7b ) is one in the red region, preferably one emitting in the range 600 to 650 nm LED. LED lighting device according to one of claims 1 to 8, comprising a phosphor layer, all LEDs ( 7a . 7b . 7c ), wherein the phosphor is excited by blue (about 460 nm) and the remaining monochromatic LEDs are slightly attenuated. LED lighting device according to one of claims 1 to 11, wherein the LEDs ( 7a . 7b . 7c ) are arranged so close to each other that a homogeneous light beam or a homogeneous light beam is generated. LED lighting device according to one of claims 1 to 12, wherein a at the power connections ( 8a . 8b ) connected LED driver ( 13 ) for operating the LEDs ( 7a . 7b ) is disposed within the LED lighting means. LED illuminant according to one of claims 1 to 13, comprising a glass bulb 5 with at least one glare-free area based on a micro or nanostructure, in particular a Fresnel structure. LED lighting device according to one of claims 1 to 14, comprising at least one optical filter formed thereto is, selectively and selectively a share of the LED bulb forwarding or filtering the emitted light.