WO2012175385A1

WO2012175385A1 - Led lighting device and method for producing an led lighting device

Info

Publication number: WO2012175385A1
Application number: PCT/EP2012/061197
Authority: WO
Inventors: Robert Kraus
Original assignee: Osram Ag
Priority date: 2011-06-21
Filing date: 2012-06-13
Publication date: 2012-12-27
Also published as: DE102011077898A1

Abstract

The invention relates to an LED lighting device (10), comprising a substrate (11), wherein the substrate (11) is populated with at least one LED chip (15), a light outlet surface (16) of the at least LED chip (15) faces the substrate (11), and the substrate (11) is light-transmissive at least in the area of the at least one LED chip (15). The method is used to produce an LED Lighting device (10) and comprises at least the following steps: providing a light-transmissive, in particular transparent, substrate (11); and applying at least one LED chip (15) to the substrate (11) in such a way that an associated light outlet surface (16) of the at least one LED chip (15) faces the substrate (11).

Description

description

LED lighting device and method for manufacturing an LED lighting device

The invention relates to an LED lighting device with a carrier which is equipped with at least one light-emitting diode (LED) chip. The invention further relates to a method for producing such an LED lighting device.

So far, LED chips with their back in

prefabricated housings, on stamped copper sheets (so-called "lead frames") or applied to boards. For this purpose, the LED chip, which has an electrical contact on the underside, adhesively bonded to a bottom surface or

soldered, and then a second, top-side contact is contacted by wire bonding. Subsequently, a transparent potting is applied to the LED chip, so that a mechanical protection and at the same time a possibility of light emission are given. For white or white

Light-emitting conversion light-emitting diodes (LEDs) in or below this casting are typically additionally a wavelength-converting phosphor

("Conversion phosphor") introduced. These arrangements have the disadvantage that they are expensive to mount and expensive and also allow a little compact arrangement.

It is the object of the present invention to at least partially overcome the disadvantages of the prior art and in particular to provide a low-cost LED lighting device with an increased efficiency.

This object is achieved according to the characteristics of the independent

Claims solved. Preferred embodiments are

in particular the dependent claims. The object is achieved by an LED lighting device, comprising a carrier, wherein: the carrier is equipped with at least one LED chip, a light exit surface of the at least one LED chip faces the carrier and the carrier at least in the region of at least one LED chip Chips is translucent. Such an LED lighting device is particularly simple and cheaper by means of

Production steps can be produced. It has also been shown that this LED lighting device has an increased efficiency (in lm / W). Also, such an LED lighting device is very compact and in particular has a low height.

Due to the fact that the light exit surface of the at least one LED chip faces the carrier, it radiates from the associated at least one light exit surface

emitted light through the carrier. On a transparent potting for the at least one LED chip, which is very precise and expensive to apply, can be dispensed with. In addition, the LED chip is reliably protected by the carrier.

An LED chip may, in particular, be understood to mean an unpacked LED chip. Under a LED chip can

in particular a LED naked chip or a LED die understood. However, e.g. It is also possible to use organic LEDs (OLEDs, for example polymer OLEDs).

The LED chip may be a volume emitter, e.g. a sapphire LED. The LED chip may alternatively be a surface emitter, e.g. based on ThinGaN (including InGaN or AlInGaP, etc.

A wavelength or peak wavelength of the of

Light emitting surface of a light emitting diode LED chip is not limited and may, for example, IR light, red light, orange light, yellow light, green light, blue light, UV light, etc. correspond. Are several LED Chips present, these light can radiate a same color or light of different color.

It is a training that the carrier is made of

translucent ceramic, e.g. made of aluminum dioxide, or quartz glass. Such a carrier is special

resistant. Also, the carrier may consist of glass, which is inexpensive and easy to shape. In addition, the carrier may be made of a translucent plastic and thus can be made simple and inexpensive (e.g.

by means of an injection molding process) and especially like

be shatterproof. Further, the carrier may be made of silicone, which is, for example, resistant to radiation, flexible (flexible) and inexpensive. In addition, the carrier may be made of resin, especially epoxy resin. In addition, the carrier may consist of indium tin oxide (ITO), which is electrically conductive.

The carrier may in particular be plate-shaped.

It is an embodiment that the carrier is transparent at least for the light emerging from the light exit surface. So a particularly high efficiency can be achieved. The carrier may in particular be completely transparent, which further increases efficiency.

It is still an embodiment that the carrier at least for the light emerging from the light exit surface

translucent, in particular may be a diffusely transparent support. Thus, high uniformity of the light emitted from the LED lighting device can be achieved. For example, the carrier may be made of frosted glass or milky white silicone. It is yet another embodiment that the

Light exit surface over (at least) one

Phosphor layer rests on the support. In other words, between the light exit surface and the carrier at least one phosphor layer is present. The light emerging from the light exit surface is at least partially converted or converted with respect to its wavelength by the at least one phosphor present in the phosphor layer, in particular in the direction of a larger one

Wavelength ("down conversion"). Thus, (in this case through the carrier) wavelength-converted light and optionally non-wavelength-converted light emerging from the light exit surface ("primary light") are emitted by the LED lighting device. For example, that may be

Primary light be blue light, which is partially converted into yellow light, so that the LED lighting device emits a blue-yellow or white mixed light. Alternatively, blue primary light may be partially converted to red light and partially to green light (by means of two

different phosphors), or ultraviolet

Primary light turns into red, green and blue light

converted (by means of three different phosphors), which can also give a white mixed light. The white mixed light likes warm white mixed light or cold white

Be mixed light. However, a non-white mixed light can be generated.

As a phosphor (often called "phosphor") can

In particular, any solid material may be designated which by excitation with light (including ultraviolet light) can produce visible light and / or infrared light. Wavelength conversion may be based in particular on fluorescence (as instantaneous light emission, in particular in the case of short-wave illumination) or phosphorescence (as time-delayed fluorescence)

Light emission, especially after short-wave illumination) are based. A phosphor may in particular be an inorganic, crystalline substance, which by technical introduction of impurities into its crystal lattice a technical

Usable light yield yields. The phosphor may in particular be based on sulfides (zinc sulfide, zinc-cadmium sulfide, zinc sulfide-selenide), silicates (zinc silicate, such as, for example).

Willemite, Zinkberylliumsilikat) or zinc oxides. When _.

For example, ZnS: Mn (orange red), ZnS: Ag (blue), ZnS: Cu (green), or ZnS: rare earths (red to blue-green) can be used. Also, the lanthanides europium (Eu) and

Gadolinium (Gd), e.g. in the form of

europium doped yttrium oxide.

It is also an embodiment that at least one phosphor layer is present on the side of the carrier opposite the at least one LED chip. These

The phosphor layer may be present in addition to or as an alternative to the phosphor layer between the phosphor layer and the carrier. With an additional presence like so, if these two phosphor layers one

have different phosphor or phosphor mixture, an efficiency-reducing interaction of two phosphors are reduced. Especially with a

Alternative (exclusive) presence on the side opposite the at least one LED chip has the advantage that the LED chip can be connected to the carrier more easily and more strongly, in particular via a

Adhesive, in particular adhesive layer.

It is also a development that at least one

Has phosphor as filler. So like to one

dispense separate application of a dedicated phosphor layer, or it may be achieved in a compact and robust way further wavelength conversion with little mutual influence of the phosphors.

It is still an embodiment that the light exit surface rests on the carrier via an adhesive layer. Thus, a secure and large-scale connection of the

Light exit surface can be achieved with the carrier in a compact manner. The adhesive layer is preferably in

Substantially translucent to obtain a high luminous efficacy. In this case, the adhesive need not be translucent as a bulk material, if it is sufficiently thin is present. A thickness of the adhesive layer is preferably less than 100 micrometers, in particular less than 50 micrometers, in particular less than 25 micrometers. It is still an embodiment that the light exit surface rests directly on the support. The LED chip can then be connected, for example via a potting with the carrier. This embodiment has the advantage that

Light losses can be kept very small.

It is a development that a space is filled laterally next to the at least one LED chip with a filling material. This allows a high stability of the LED lighting device. In the case of several LED chips, this space is in particular a space laterally between the LED chips. The filling material is in particular up to the height of the at least one LED chip, i. flush with it, filled up, which allows easy further processing. The

Filler material may be in particular a potting material, but also a template, etc.

It is a further embodiment that the filling material is designed to be reflective, that is to say that a space is filled laterally next to the at least one LED chip with a reflective filling material. Thereby, a luminous efficiency of the LED lighting device can be improved, because (for example, due to a wavelength conversion or an interfacial reflection) light not passing through the carrier is at least partially retrievable by the carrier again. The reflective filling material may, for example, be coated with reflective particles or the like. filled base material or e.g. a reflective thin film (e.g., foil) covered by or covering a non-reflective filler material.

It is still an embodiment that a space laterally next to the at least one LED chip with a transparent

Material is filled and above or below the transparent material is a reflective layer is present, for example in the form of a thin film.

The filling material filling the space laterally next to the at least one LED chip may, for example, be made of resin

(in particular epoxy resin), silicone, glass or ceramic as base material.

It is furthermore an embodiment that a rear side (a side facing away from the light exit surface) of the at least one LED chip has at least one chip contact. This facilitates electrical contacting of the LED chip. In particular, all, e.g. two, chip contacts on the back to be present.

It is also an embodiment that a rear side (a side facing away from the light exit surface) of the LED lighting device is covered with a cover layer, which has a respective recess above the at least one chip contact. Thus, a back protection of the LED lighting device, for example, against mechanical stress and / or chemical corrosion

provided. The recess allows a simple electrical contacting of the at least one LED chip.

The cover layer can be designed to be reflective and thus the function of the above the transparent material

take over or be existing reflective layer. The cover layer may for example consist of a reflective material or a reflective

Underside or topside, e.g. formed with a reflective foil.

It is also an embodiment that the at least one recess is filled with an electrically conductive material. This makes it easier to contact the respective LED chip easily. It is a further development that the recess has a larger area than that of it electrical connected chip contact. A free surface of the electrically conductive material may in particular as a solder joint, weld, splice or as a

Bondpad for contacting by means of a bonding wire

be designed. The free surface may provide both electrical and thermal connection to at least one external component (e.g., electrical connections). The electrically conductive material may also extend beyond the recess and then

In particular, extend laterally over the cover layer to provide a particularly large and easy to handle or electrically contactable surface.

It is still a further development that the recess is at least partially filled with a metal or metal-containing material (e.g., silver paste), e.g. in form of a

Metallization. The metal or metal-containing material may be obtained, for example, by a galvanic process,

Sputtering, embossing or printing process can be applied. With the metallization of the recess can

at the same time a wiring or similar be applied to the cover layer.

The problem is also solved by a method for

Producing an LED lighting device, the method comprising at least the following steps: (a) providing a light-transmitting, in particular transparent,

carrier; (b) applying at least one LED chip to the carrier so that an associated light exit surface of the

at least one LED chip faces the carrier; and further optionally: (c) introducing filler material at least adjacent to the at least one LED chip; (d) applying a cover layer; (E) exposing chip contacts of the at least one LED chip by creating recesses in the

Cover; and (f) filling the recesses with electrically conductive material. The method gives the same advantages as the described LED lighting device and can also be configured analog. It is for example an embodiment that the method further comprises the step (g): applying one of the at least one light exit surface optically downstream

Has phosphor layer. This step (g) may

for example between step (a) and step (b)

be performed to position the phosphor layer between the light exit surface and the carrier.

Alternatively or additionally, step (g) may be carried out after step (f), in particular in order to position the phosphor layer on that side of the carrier which faces away from or faces the light exit surface.

It is still an embodiment that step (b) comprises: applying at least one LED chip by means of a

Adhesive to the carrier so that an associated

Light exit surface of the at least one LED chip the

Carrier faces. The adhesive layer is preferably substantially translucent in order to obtain a high luminous efficacy. The adhesive need not be translucent as a bulk material. Step (b) may therefore be e.g. the sub-step: applying an adhesive layer on the

Carrier or on a carrier

Phosphor layer, in particular at least on a surface to be contacted with a light exit surface having.

After, with or before step (b) can also be the step:

Applying at least one electronic component (eg resistor, coil, etc.) to the carrier or to a phosphor layer on the carrier can be carried out. The at least one electronic component is preferably applied to the same side of the carrier as the at least one LED chip. Step (c) may be performed by, for example, laying, casting, laminating, molding, and so on. Step (e) may in particular comprise only partial exposure of chip contacts. The exposure may be performed, for example, by chemical etching, mechanical material removal, laser ablation, plasma etching, etc. Step (f) can be achieved for example by selective embossing, by a planar metallization, for example by sputtering, in particular with a subsequent structuring or by a structured coating with a subsequent metallization.

The above-described characteristics, features and advantages of this invention as well as the manner in which they are achieved will become clearer and more clearly understood

In connection with the following schematic description of exemplary embodiments that are associated with the

Drawings are explained in more detail. It can to

Clarity identical or equivalent elements must be provided with the same reference numerals. Fig.l shows a sectional view in side view a

LED lighting device according to a first embodiment; and

2 shows a sectional side view of a

LED lighting device according to a second embodiment

Fig.l shows a sectional side view of an LED lighting device 10 according to a first embodiment. The lighting device 10 has a carrier 11

transparent glass on. On a top 12 of the carrier 11, a phosphor layer 13 of a defined thickness is applied over a large area, which has a blue light in yellow light wavelength converting or converting phosphor. On the phosphor layer 13 is a thin

Adhesive layer 14 or adhesive layer of transparent adhesive applied to an LED chip 15 thereto

to glue. The LED chip 15 contacts with its light exit surface 16, the adhesive layer 14, so that the light exit surface 16 faces the carrier 11.

Between light exit surface 16 and the carrier 11 are thus the adhesive layer 14 and the

Phosphor layer 13.

The space laterally next to the LED chip 15 is with a

transparent filling material 17, e.g. potted with resin or silicone. In addition to the LED chip 15 shown, further LED chips may be present on the carrier 11, in which case the space is filled laterally between the LED chip 15 with the transparent filling material 17. The

Filling material 17 is filled up to an upper edge of the LED chip 15 and thus flush with its upper side.

On top of the LED chip 15 and the

Filling material 17 is a reflective

Cover layer 18, which have a recess 20 above chip contacts 19 of the LED chip 15. The cover layer 18 may be, for example, resin or silicone equipped with a reflective film or reflective particles.

The recess 20 is filled with a metallic conductive material 21 which extends upwards over the

Recess 20 away and laterally over the cover 18 extends. Thus, a large contact surface 22 to

achieved electrical and possibly also thermal contact with electrical terminals 23.

During operation of the lighting device 10, the LED chip 15 is connected via the electrical connections 23 and further via the metallic conductive material 21 and the chip contacts 19 electrically powered and so activated for light emission. The light emerges as here blue primary light from the

Light exit surface 16 in the direction of the carrier 11 and the phosphor layer 13 and passes through the

Adhesive layer 14. In the phosphor layer 13, part of the blue primary light becomes yellow light

wavelength-converted. Thus, by the

Phosphor layer 13 a from the blue, through the

Fluorescent layer 13 passing, primary light and the wavelength-converted yellow light generated white

Mixed light in the direction of the carrier 11 and radiated through the carrier 11 therethrough.

From the phosphor layer 13 or an interface

reflected light at least partially passes through the transparent filling material 17 and is reflected by the support 11 on the reflective covering layer 18

reflected back, which increases a light output. Fig. 2 shows a sectional side view of an LED lighting device 24 according to a second embodiment. The LED lighting device 24 is similar to

Lighting device 10 constructed, with the

However, phosphor layer 13 is now below the support 11, that is, on the side facing away from the LED chip 15 side of the carrier. As a result, attachment of the LED chip 15 to the carrier 11 is made possible only via the adhesive layer 14.

Although the invention is shown in detail by the

Embodiments have been further illustrated and described, the invention is not limited thereto and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention. LIST OF REFERENCE NUMBERS

10 LED lighting device

11 carriers

12 top of the vehicle

13 phosphor layer

14 adhesive layer

15 LED chip

16 light exit surface

17 filling material

18 covering layer

19 chip contact

20 recess

21 conductive material

22 contact area

23 electrical connection

24 LED lighting device

Claims

claims

An LED lighting device (10; 24) comprising a carrier (11), wherein

- The carrier (11) is equipped with at least one LED chip (15),

- A light exit surface (16) of the at least one LED chip (15) facing the carrier (11) and

- The support (11) at least in the region of the at least one LED chip (15) is translucent.

2. LED lighting device (10; 24) according to claim 1, wherein the carrier (11) at least for the from

Light exit surface (16) emerging light is transparent.

3. LED lighting device according to claim 1, wherein the carrier at least for the out of the light exit surface

escaping light is translucent.

4. LED lighting device (10) according to any one of the preceding claims, wherein the light exit surface (16) via a phosphor layer (13) rests on the carrier (11). 5. LED lighting device (10; 24) after one of

preceding claims, wherein the light exit surface (16) via an adhesive layer (14) rests on the carrier (11). 6. LED lighting device according to one of claims 1 to 3, wherein the light exit surface rests directly on the support.

7. LED lighting device 824) according to any one of the preceding claims, wherein at the at least one LED chip

(15) opposite side of the carrier (11) at least one phosphor layer (13) is present. LED lighting device according to one of the preceding claims, wherein a space is laterally adjacent to the at least one LED chip (15) filled with a reflective material.

LED lighting device (10; 24) according to one of

previous claims, wherein a space laterally adjacent to the at least one LED chip (15) with a

transparent material (17) is filled and above the transparent material (17) a reflective layer (18) is present.

LED lighting device (10; 24) according to one of

The preceding claims, wherein a back of the at least one LED chip (15) at least one

Has chip contact (19).

LED lighting device (10; 24) according to claim 10, wherein a rear side of the LED lighting device (10; 24) is covered with a covering layer (18) which above the at least one chip contact (19) has a respective one

Has recess (20).

The LED lighting device (10; 24) of claim 11, wherein the at least one recess (20) is filled with an electrically conductive material (21).

A method of manufacturing an LED lighting device (10), the method comprising at least the following

Steps:

(a) providing a translucent,

in particular, transparent support (11);

(B) applying at least one LED chip (15) on the carrier (11), that an associated

Light exit surface (16) of the at least one LED chip (15) facing the carrier (11);

(c) introducing filler material (17) at least in addition to the at least one LED chip (15); (d) applying a cover layer (18);

(e) exposing chip contacts (19) of the at least

an LED chip (15) by generating

Recesses (20) in the cover (18);

(F) filling the recesses (20) with electrical

conductive material (21).

14. The method of claim 13, wherein the method further comprises the step of:

(g) applying one of the at least one

Light exit surface (16) optically downstream phosphor layer (13)

having .

15. The method according to any one of claims 13 or 14 wherein

Step (b) comprises: applying at least one LED chip (15) to the carrier (11) by means of an adhesive (16) such that an associated light exit surface (16) of the at least one LED chip (15) extends to the carrier (11) is facing.