WO2010052135A2 - Light-emitting diode arrangement - Google Patents

Abstract

The invention relates to a light-emitting diode arrangement comprising a base plate, on the surface of which at least one light-emitting diode or a light-emitting diode array and at least one lens are arranged, wherein at least one form-closed and/or force-closed connection between the base plate and the lens is provided. The lens can thus be positioned over a light-emitting diode with increased accuracy, wherein a fatigue strength of the connection is ensured even in the event of thermal and mechanical loads.

Description

 description

LED array

Technical area

The invention relates to light-emitting diode arrangements according to the preamble of patent claim 1.

State of the art

In order to focus or diffuse the light emitted by light emitting diodes, lenses are used which can be arranged directly on the light emitting diode.

Document DE 35 32 821 C2 discloses a light-emitting diode arrangement in which a spherical lens is fixed by adhesive on a flat surface of a light-emitting diode.

A disadvantage of such light-emitting diode arrangements is that the exact positioning of the lens over the light-emitting diode is difficult. Furthermore, the lens may deviate from its desired position during the drying time of the adhesive because different viscous forces of the adhesive may act on the lens.

In addition, under the influence of thermal fluctuations and vibration, a permanent connection of the lens to the LED is not sufficiently secured.

Presentation of the invention

The object of the present invention is to provide a light emitting diode array in which a lens with increased positioning accuracy over a light emitting diode is attached, with a permanent connection should be secured even under thermal and mechanical loads.

This object is achieved by a Leuchtdiodenan- order according to claim 1.

Particularly advantageous embodiments are described in the dependent claims.

The light-emitting diode arrangement according to the invention has a base plate, on the surface of which at least one light-emitting diode or light-emitting diode array and at least one lens are arranged, wherein at least one frictional and / or positive connection is provided between the base plate and the lens. As a result, the lens can be positioned with increased accuracy over the light-emitting diode, wherein a fatigue strength of the compound is secured even under thermal and mechanical loads.

In a particularly preferred embodiment, the positive connection is a snap connection. As a result, the mounting of the lens on the light emitting diode or on the surface of the base plate is simplified.

In a preferred development of the light-emitting diode arrangement according to the invention, at least one elastic snap-on section on the lens and in each case a recess receiving the snap-action section are arranged on the base plate. With a certain elasticity of the material of the lens and of the snap portion or with a correspondingly thin design of the snap portion, the lens can thus be integrally formed with the snap portion, whereby the production cost of the light-emitting diode arrangement can be reduced. In a variant of the light-emitting diode arrangement according to the invention, at least one pin with elastic snap portion extends through in each case one recess of the base plate, wherein in each case a recess receiving the snap portion of the pin is arranged on the lens. As a result, the pin can be made of a low-cost material.

In a preferred development of the positive connection, at least one U-shaped gripping portion of the lens engages around an edge portion of the base plate. Thus, the lens may e.g. be pushed onto the base plate along its surface, with a secure connection of the lens is ensured with the base plate.

In another preferred development, at least one bending section of the base plate is in each case one

Recess of the lens added. Thus, by bending the bent from the base plate bending section in

Direction of the lens / optics either before mounting or during assembly a permanent connection with the lens can be achieved.

In addition, it is preferred if at least one

Plastic screw through one through hole each

Base plate extends in each case a blind hole of the lens. This represents another permanent and precise connection.

In a further preferred development, a hook portion of the lens extends through a slot in the base plate and engages behind it. This connection technology provides a simple and precise assembly technique. In addition, it is preferred if at least one

Pin portion of the lens extends through a respective through hole of the base plate, whereby a position of the lens on the surface of the base plate can be mechanically defined.

It is advisable for reasons of security, that the pin portion is caulked or hot stalked.

Or the pin portion is preferably connected to a lock washer wherein either an inner portion of the lock washer dips into a groove of the pin portion, or the lock washer has teeth that engage the pin portion.

Alternatively, it is preferable if an end portion of the pin portion is welded to a sleeve.

In a particularly preferred development of the light-emitting diode arrangement according to the invention, a wire which bears against a foot section of the lens engages behind the base plate.

In a preferred development, at least one securing pin extends through in each case one through hole of the base plate into a respective bore or recess of the lens. As a result, a position of the lens on the base plate is mechanically defined.

Furthermore, it is preferred if contact areas of the positive connection or contact areas between the base plate and the lens have material-connected or adhesive-connected sections. As a result, detachment of the lens from the base plate is additionally prevented. It is particularly preferred if the adhesive has approximately spherical filling elements. As a result, a layer thickness of the adhesive is defined, and with temperature fluctuations, a different expansion of the connected sections is facilitated.

For reasons of temperature resistance or the dissipation of the heat of the LEDs, it is preferred if the base plate is a metal core board. In addition, a base plate designed as a metal core board is mechanically particularly stable.

For example, when used in an automotive headlamp, it is preferred if the lens is made of polycarbonate.

Brief description of the drawings

In the following, the invention will be explained in more detail with reference to exemplary embodiments. Show it:

Figure 1 shows a first embodiment of a

Light emitting diode arrangement in section;

Figure 2 shows a detail of a second embodiment of a light emitting diode array in section;

Figure 3 shows a detail of a third embodiment of a light emitting diode array in section;

Figure 4 shows a detail of a fourth embodiment of a light emitting diode array in section;

Figure 5a shows a fifth embodiment of a light emitting diode array in section; FIG. 5b shows the fifth exemplary embodiment according to FIG. 5a in a perspective view from below;

6a, a sixth embodiment of a light-emitting diode arrangement in a perspective exploded view from below;

FIG. 6b shows the sixth exemplary embodiment according to FIG. 6a in a perspective view from below;

Figure 7a shows a seventh embodiment of a

Light-emitting diode arrangement in a plan view; and

FIG. 7b shows the seventh exemplary embodiment according to FIG. 7a in a view from below.

Preferred embodiment of the invention

Figure 1 shows a first embodiment of a light emitting diode array in section, which consists essentially of a lens 1 and a metal core board 2. The lens 1 has substantially the shape of a circular cylinder, wherein on a (in Figure 1) lower shell portion a flattening is provided, which is a surface of the metal core board 2 is facing.

The flattening has two in the direction of the center of the lens 1 inclined symmetrical flanks 4. Centered between the flanks 4, the lens 1 has a projection 6 which extends in the direction of the metal core board 2 and a flat approximately parallel to the surface of the metal core board 2 extending surface , The light-emitting diode or the light-emitting diode array 8, which has a substantially rectangular cross section, is mounted on the lens 1 facing surface of the metal core board 2 at a central position.

The projection 6 serves as an optical interface between the light emitting diode 8 and the main portion 3 of the lens first

During operation of the light-emitting diode arrangement according to the invention, the light beams emitted by the light-emitting diode 8 (in FIG. 1) run upwards or obliquely upward through the projection or the optical interface 6 in the direction of the main section 3 of the lens 1. The light beams leave the main section 3 by its lateral surface 10, wherein the light rays are bundled at this transition (in Figure 1) upwards.

The fastening technique of the lens 1 according to the invention on the surface of the metal core board 2 will be described below. The lens 1 has at the transition of the edge 4 to the lateral surface 10 depending on a gripping portion 11 which engages around and engages in each case an opposite edge portion 13 of the metal core board 2.

The gripping portions 11 extend (in Figure 1) to the outside and have grooves which are approximately perpendicular to the plane (of Figure 1), wherein the distance between the two mutually substantially mutually parallel groove bases 16 corresponds approximately to the width of the metal core plate 2, while the Width of the grooves about the thickness of the metal core board 2 corresponds.

Thereby, the lens 1 is precisely positioned and held in two directions on the metal core board 2, while the third direction perpendicular to the plane of the drawing is fixed by two locking pins 18. These locking pins 18 are inserted after a precise positioning of the lens 1 on the metal core board 2 by a respective through hole of the metal core board 2, wherein they each extend into a blind hole, which are provided between the flanks 4 and the gripping portions 11 of the lens 1.

Since the securing pins 18 and the through holes formed in the metal core board 2 have approximately equal diameters and the diameter of the blind holes in the lens 1, on the other hand, have a minimally reduced diameter, the two securing pins 18 are secured against falling out. They fix in operative connection with the gripping portions 11, the position of the lens 1 on the metal core board 2. Thus, a high positioning accuracy and permanent fixation of the lens 1 and its projection 6 is ensured on the light emitting diode 8.

FIG. 2 shows a section of a second exemplary embodiment of a light-emitting diode arrangement according to the invention in a lateral section, wherein a lens 101 has a main section 3 and a projection 6 which essentially correspond to those of the first exemplary embodiment according to FIG.

A foot 112 of the lens 101 has a flat bottom, with which it rests on top of the metal core board 102.

At the bottom of the foot 112, a recess 114 and adjacent thereto a web 116 are formed.

In the area of the recess 114, a bending section 118 is punched out in the metal core board 102, the

Length about and its width (in FIG. ne in) correspond exactly to that of the recess 114.

During assembly of the light-emitting diode arrangement according to FIG

2, the lens 101 is placed on the metal core board 102 and accurately positioned so that the bend portion 118 can be bent up out of the metal core board 102 such that its free end portion engages the web 116 of FIG

Lens 101 engages behind. In this case, the free end section of the bending section 118 bears against the abutment surface 120 of the recess 114.

The same combination of a foot 112 with a

Recess 114 and received therein bending portion 118 is at least once on the other side of the

Light emitting diode 8 and the projection 6 arranged in mirror image.

Thus, the lens 101 is secured against displacement on the metal core plate 102 on the one hand by the abutment of the two bending sections 118 on the two contact surfaces 120 and on the other hand by the same dimensions of the bending sections 118 and the recesses 114 perpendicular to the plane. Furthermore, a detachment of the lens 101 from the metal core board 102 is prevented by the fact that the two bending sections 118 engage behind the respective webs 116.

FIG. 3 shows a section of a third exemplary embodiment of a light-emitting diode arrangement according to the invention in a lateral section, the main section 3 and the projection 6 of the lens 201 and the metal core board 2 essentially corresponding to those of the two other exemplary embodiments according to FIGS. 1 and 2. A foot 212 of the lens 201 rests with its lower surface on the upper surface of the metal core board 2.

A pin portion 222 extends downwardly from the foot 212 through a through hole of the metal core board 2

Pin portion 222 has an elastic snap portion

224, which engages behind the metal core plate 2 at its (in Figure 3) lower side.

The arrangement shown in Figure 3 from the foot 212 with the pin portion 222 and the snap portion 224 is also provided in mirror image on the (in Figure 3) right side of the light emitting diode array.

By the two pin portions 222, the lens 201 is secured against displacement on the surface of the metal core board 2, while the two snap portions 224 prevent detachment of the lens 201 from the metal core board 2.

When mounting the third embodiment of the light-emitting diode arrangement, first the two Schnappab- sections 224 and then the two pin portions 222 (in Figure 3) introduced from above into the respective through holes until the two feet 212 on the surface of the metal core board 2 approximately abut and the two snap portions 224 are spring back to the end position shown.

FIG. 4 shows a section of a fourth exemplary embodiment of a light-emitting diode arrangement according to the invention in a lateral section, wherein the main section 3 and the projection 6 of the lens 301 essentially correspond to those of the preceding exemplary embodiments, while the metal core board 2 corresponds to those of the embodiments 1 and 3 (according to FIGS. 1 and 3).

A foot 312 of the lens 301 rests with its lower surface on the surface of the metal core board 2 and has on its underside a substantially kreiszylin- derförmige recess 314 and a web 316 on.

A substantially circular cylindrical locking pin 318 extends from below through a through hole of the metal core board 2 in the recess 314, both having an approximately equal diameter.

At the (in Figure 4) the upper end portion of the locking pin 318, a snap portion 324 is formed, which engages behind the web 316 of the lens 301.

The pin portion 318 has a diameter-enlarged head 318a, with an upper surface of the head 318a and a lower surface of the snap portion 324 spaced apart to correspond to a thickness of the ridge 316 and the metal core board 2.

The foot 312 with the recess 314 and the web 316 and the security pin located in the through hole of the board 318 with the snap portion 324 is repeated on the (in Figure 4) right side of the light emitting diode array mirror image.

During assembly, the lens 301 is accurately positioned on the metal core board 2, whereupon the locking pins 318 (in FIG. 4) are inserted from below through the through holes of the metal core board 2 until their heads 318a abut against the underside of the metal core board 2 and simultaneously their Snap portions 324 spring over the webs 316. The locking pins 318, which are snugly received in the through-holes of the metal core board 2 and in the substantially cylindrical recesses 314 of the lens 301, prevent the lens 301 from moving on the surface of the metal core board 2. The heads 318a which engage under the metal core board 2 prevent this , and the snap portions 324, which engage over the webs 316, a lifting of the lens 301 of the metal core board second

FIGS. 5a and 5b show a fifth exemplary embodiment of a light-emitting diode arrangement according to the invention, the main section 3 and the projection 6 of the lens 401 and the light-emitting diode 8 corresponding to those of the previous exemplary embodiments.

Notwithstanding the preceding embodiments, the metal core board 402 has a through hole which is formed as a rectangular slot 426, wherein the length of the slot 426 corresponds to the thickness of the lens 401 (see Figure 5b). A hook portion 428 extends downwardly from the lens 401 (in FIG. 5a) through the slot 426. In this case, the (in FIG. 5a) right long edge of the slot 426 is encompassed by the hook portion 428. The hook portion 428 has a width that corresponds to the length of the slot 426 or may be formed shorter.

At the left (in FIG. 5a) region of the light emitting diode array, a cylindrical pin portion 422 extends from above through a through hole of a corresponding diameter provided in the metal core board 402.

During assembly of the light-emitting diode arrangement, first the hook portion 428 of the lens 401 is moved through the Slot 426 out and (in Figure 5a) shifted to the right, so that the hook portion 428, the metal core board 402 engages behind. Subsequently, the left-hand part (in FIG. 5a) of the lens 401 is lowered onto the metal-core board 402, the pin section 422 being guided through the through-hole of the metal core 1 at 402. In a last step, the pin portion 422 is caulked so that the lens 401 can not detach from the metal core board 402.

Thus, the projection 6 of the lens 401 is permanently and precisely positioned above the light emitting diode 8.

FIG. 6 a shows a sixth exemplary embodiment of a light-emitting diode arrangement according to the invention in a perspective illustration from below, the light-emitting diode arrangement essentially consisting of a lens 501, a metal-core board 502 and four synthetic material sleeves 530. The lens 501 has on its underside four pin portions 522, which are guided during assembly through correspondingly arranged through holes of the metal core board 502.

FIG. 6b shows the sixth exemplary embodiment according to FIG. 6a in a perspective view from below, wherein the sleeves 530 are fastened to the pin sections 522.

The sleeves 530 have a height corresponding to the length of the pin portions 522 minus the thickness of the metal core board 502 while having an inner diameter corresponding to the outer diameter of the locking pins 522. The attachment of the sleeves 530 to the pin portions 522 is carried out by a welding method, such. Vibration welding, hot plate welding, hot air welding, laser welding, spin welding, infrared welding or gluing.

FIG. 7 a shows a seventh exemplary embodiment of a light-emitting diode arrangement according to the invention in a top view, wherein a lens 601 has a substantially spherical main section 603 and a surface section 632 which rests on the metal core board 602. The surface portion 632 has an approximately rectangular outer periphery whose longer sides are longer than the diameter of the main portion 603 of the lens 601, during which shorter sides approximately correspond to this diameter.

An approximately rectangular cutout 634 is provided at an edge portion of the metal core board 602 disposed adjacent to a long side of the land portion 632, while two approximately square cutouts 636 are provided at the opposite edge portion of the metal core board 602. The respective outer side flanks of the cutouts 636 are at a distance from one another which corresponds to that of the two side flanks of the cutout 634. This distance is less than the diameter of the main portion 603 of the lens 601.

FIG. 7b shows the seventh exemplary embodiment according to FIG. 7a in a view from below.

At two diagonally spaced locations on the underside of the surface portion 632, a pin portion 622 each extending through through holes of the metal core board 602 similar to those of the fifth and sixth embodiments are arranged. These pin portions 622 prevent displacement and rotation of the lens 601 on the metal core board 602. Referring to FIGS. 7a and 7b, lifting of the lens 601 from the metal core board 602 is prevented by a central portion 638a of a wire engaging behind a land 640 formed between the cutouts 636, while a major portion 638b of the wire extends above the land portion 632 extends, and end portions 638c extend through the cutout 634 and engage behind the metal core plate 602.

All exemplary embodiments of the light-emitting diode arrangement according to the invention afford a precise and permanent seating of the respective lens or its projection serving as an optical interface on the metal core board or the light-emitting diode mounted thereon. This means an exact beam path and an optimal yield of the light emitted by the light emitting diode.

In contrast to the exemplary embodiments shown, the lens can also be glued and hot-caulked, the gluing offering good vibration resistance and hot caulking providing good resistance to temperature changes.

Disclosed is a light emitting diode array with a base plate, on the surface of which at least one light emitting diode or a light emitting diode array and at least one lens are arranged, wherein at least one positive and / or non-positive connection between the base plate and the lens is provided. As a result, the lens can be positioned with increased accuracy over a light-emitting diode, wherein a fatigue strength of the compound is secured even under thermal and mechanical loads.

Claims

claims A light-emitting diode arrangement having a base plate (2; 102; 402; 502; 602) on the surface of which at least one A light-emitting diode or a light-emitting diode array (8) and at least one lens (1; 101; 201; 301; 401; 501; 601) are arranged, characterized by at least one frictional and / or positive connection between the base plate (2; 102; 402; 502, 602) and the lens (1; 101; 201; 301; 401; 501; 601). 2. Light emitting diode arrangement according to claim 1, wherein the positive connection is a snap connection. 3. Light emitting diode arrangement according to claim 2, wherein at least one elastic snap portion (224) on the Lens (201) and each one the snap portion receiving recess on the base plate (2) are arranged. 4. Light-emitting diode arrangement according to claim 2, wherein at least one pin (318) with an elastic Schnappab- cut (324) through a respective recess of the base plate (2), and in each case a snap portion (324) receiving recess (314) on the Lens (301) is arranged. 5. Light emitting diode arrangement according to one of the preceding claims, wherein at least one U-shaped gripping portion (11) of the lens (1) in each case surrounds an edge portion (13) of the base plate (2). 6. Light-emitting diode arrangement according to one of the preceding claims, wherein at least one bending portion (118) of the base plate (102) in each case a recess (114) of the lens (101) engages. 7. Light-emitting diode arrangement according to one of the preceding claims, wherein extending at least one plastic screw through a respective through hole of the base plate in each case a blind hole of the lens. 8. Light emitting diode arrangement according to one of the preceding claims, wherein a hook portion (428) of the lens (401) extends through a slot (426) of the base plate (402) and engages behind the base plate (402). 9. Light-emitting diode arrangement according to one of the preceding claims, wherein at least one pin portion (222; 422; 522; 622) of the lens (201; 401; 501; 601) extends through a respective through-hole of the base plate (2; 402; 502; 602) ). The light emitting diode assembly of claim 9, wherein the pin portion (422) is caulked or hot caulked. 11. The light-emitting diode arrangement according to claim 9, having a securing disk fastened to the pin portion, wherein either an inner portion of the securing disk dips into a groove of the pin portion, or the securing disk has teeth which engage in the pin portion. 12. The light emitting diode assembly of claim 9, wherein an end portion of the pin portion (522) is welded to a sleeve (530). 13. The light emitting diode assembly of claim 9, wherein a wire (638a, 638b, 638c) engaging a top of a flat foot portion (632) of the lens (601) engages behind the base plate (602). 14. Light-emitting diode arrangement according to one of the preceding claims, wherein at least one locking pin (18; 318) in each case through a through hole of the base plate (2) in each case a bore (314) of the lens (1, 301) is immersed. 15. Light-emitting diode arrangement according to one of the preceding claims, wherein contact areas of the non-positive and / or positive connection or contact areas between the base plate and the lens have cohesive or adhesive-bonded portions. 16. Light emitting diode arrangement according to one of the preceding claims, wherein the adhesive has approximately spherical filling elements. A light emitting diode array according to any one of the preceding claims, wherein the base plate is a metal core board (2; 102; 402; 502; 602). 18. Light-emitting diode arrangement according to one of the preceding claims, wherein the lens (1; 101; 201; 301; 401; 501; 601) consists of polycarbonate. 19. A vehicle headlamp characterized by a light-emitting diode arrangement according to one of the preceding claims.