Automotive lighting device

Abstract

This invention provides an automotive lighting device (1) comprising a plurality of solid-state light sources (2) and a light guide (4). The solid-state light sources (2) are configured to emit light according to a light direction (d), each one having a light source centre (20) and each one defining a light source plane (21), which is a plane perpendicular to the light direction (d) which contains the corresponding light source centre (20). The light guide (4) has a reception inlet (40) which projects an optical profile (41) on the closest light source plane (21) according to the light direction (d), the optical profile (41) having an optical centre (42). The light sources (2) are arranged to project light beams to the reception inlet (40) of the light guide (4) in such a way that at least 70% of the light source centres (20) are closer to the optical profile (41) than to the optical centre (42).

Claims

1. An automotive lighting device comprising a plurality of solid-state light sources configured to emit light according to a light direction, each light source having a light source center and each light source defining a light source plane, which is a plane perpendicular to the light direction which contains the corresponding light source center; and a light guide with a reception inlet which projects an optical profile on a closest light source plane according to the light direction, the optical profile having an optical center; wherein the light sources are arranged to project light beams to the reception inlet of the light guide in such a way that at least 70% of the light source centers are closer to the optical profile than to the optical center, wherein each light source comprises a case which has a case surface with a side between 1 mm and 3 mm, and wherein each light source is surrounded by a copper area which is greater than 3 times an area of the case surface.

2. The automotive lighting device according to claim 1, wherein at least 80% of the light source centers are closer to the optical profile than to the optical center.

3. The automotive lighting device according to claim 1, wherein the light guide has the shape of a rod, the rod having a first extremity comprising the reception inlet.

4. The automotive lighting device according to claim 1, wherein the light guide is a circular light guide and said optical profile is a circle, a center of which being the optical center.

5. The automotive lighting device according to claim 1, wherein the light guide comprises a circular section defining a light guide radius.

6. The automotive lighting device according to claim 5, wherein at least the 70% of the light source centers are contained in a circular crown defined by a greater radius and a lower radius, the circular crown being inside the profile.

7. The automotive lighting device according to claim 6, wherein the lower radius is at least 80% of the greater radius and the greater radius is at least 80% of the light guide radius.

8. The automotive lighting device according to claim 6, wherein the light sources which have the light source centers thereof contained in the circular crown are arranged such that a shortest distance between closest sides of adjacent light source in the crown is less than a size of sides of the corresponding light source.

9. The automotive lighting device according to claim 1, wherein one of the light sources is central.

10. The automotive lighting device according to claim 1, wherein a distance between two closest light source centers is greater than 1.25 times a square root of the side of the case surface of the light sources comprising the two closest light source centers.

11. The automotive lighting device according to claim 10, wherein the light cases comprise straight sides, and the sides of the light cases of at least one pair of light sources are not parallel.

12. The automotive lighting device according to claim 1, wherein the copper area is divided into several copper area portions.

13. The automotive lighting device according to claim 1, wherein the light sources are located in a plane surface, so that the light source centers are arranged in a same plane.

14. The automotive lighting device according to claim 1, wherein the light sources perform at least one of a turning indicator or a day running light.

15. The automotive lighting device according to claim 2, wherein the light guide has the shape of a rod, the rod having a first extremity comprising the reception inlet.

16. The automotive lighting device according to claim 2, wherein the light guide is a circular light guide and said optical profile is a circle, a center of which being the optical center.

17. The automotive lighting device according to claim wherein the light guide comprises a circular section defining a light guide radius.

18. The automotive lighting device according to claim 17, wherein at least the 70% of the light source centers are contained in a circular crown defined by a greater radius and a lower radius, the circular crown being inside the profile.

19. The automotive lighting device according to claim 18, wherein the light sources which have the light source centers thereof contained in the circular crown are arranged such that a shortest distance closest sides of adjacent light source in the crown is less than a size of the sides of the corresponding light source.

20. The automotive lighting device according to claim 2, wherein a distance between two closest light source centers is greater than 1.25 times a square root of the side of the case surface of the light sources comprising two closest light source centers.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) To complete the description and in order to provide for a better understanding of the invention, a set of drawings is provided. Said drawings form an integral part of the description and illustrate an embodiment of the invention, which should not be interpreted as restricting the scope of the invention, but just as an example of how the invention can be carried out. The drawings comprise the following figures:

(2) FIG. 1 shows a perspective view of a particular example of part of an automotive lighting device according to the invention.

(3) FIG. 2 shows a view of the printed circuit board to show the arrangement of the LEDs with respect to the optical profile.

(4) FIG. 3 shows an automotive lighting device according to the invention installed in an automotive vehicle.

DETAILED DESCRIPTION OF THE INVENTION

(5) The example embodiments are described in sufficient detail to enable those of ordinary skill in the art to embody and implement the systems and processes herein described. It is important to understand that embodiments can be provided in many alternate forms and should not be construed as limited to the examples set forth herein.

(6) Accordingly, while embodiment can be modified in various ways and take on various alternative forms, specific embodiments thereof are shown in the drawings and described in detail below as examples. There is no intent to limit to the particular forms disclosed. On the contrary, all modifications, equivalents, and alternatives falling within the scope of the appended claims should be included. Elements of the example embodiments are consistently denoted by the same reference numerals throughout the drawings and detailed description where appropriate.

(7) FIG. 1 shows a perspective view of a particular example of part of an automotive lighting device 1 according to the invention.

(8) This lighting device 1 comprises a plurality of LEDs 2 configured to emit light according to a light direction d. Each LED 2 has a LED centre 20, which is considered as the geometric centre of the LED structure. In the particular embodiment shown in this figure, the LEDs 2 are located in a plane printed circuit board 3, so that the LED centres 20 are arranged in the same plane 21. This plane 21 is perpendicular to the light direction d, since all the LEDs emit light in the same direction.

(9) This lighting device 1 also comprises a light guide 4 with a reception inlet 40 which projects an optical profile 41 on the plane 21 containing the LED centres 20 according to the light direction d. In this case, since the light guide 4 has a circular section, the optical profile 41 is a circle with an optical centre 42.

(10) FIG. 2 shows a view of the printed circuit board 3 to show the arrangement of the LEDs 2 with respect to the optical profile 41.

(11) As may be seen in this figure, 8 out of 9 LED centres 20 are closer to the optical profile 41 than to the optical centre 42. In fact, a circular crown is also represented in this picture, with a greater radius r1 and a lower radius r2, wherein the lower radius r2 is 80% of the greater radius and the greater radius is 80% of the light guide radius r0. As stated before, 8 out of 9 LED centres 20 are inside this circular crown.

(12) In this particular case, the cases of the LEDs 2 have a square profile with a side of 1.6 mm. Since these LEDs are not arranged in a square array, but have an additional distance between them, the distance between any pair of LED centres 20 is at least 2 mm.

(13) Further, these light cases comprise straight sides 22. Although in this embodiment the sides 22 are parallel, in other advantageous embodiments, the sides of the light cases are not parallel, which contributes to create the additional space between them.

(14) Since the LEDs 2 are arranged in a printed circuit board 3, each LED 2 is surrounded by a copper area 5. This copper area is defined as the surface of copper which is in contact with a particular LED.

(15) As may be seen in this figure, each LED 2 is surrounded by a copper area 5. The LEDs which are not surrounded by many other LEDs have a great copper area, so their thermal behaviour is good. However, regarding the LEDs which are surrounded by many other LEDs in the devices from the state of art, the closeness of the rest of the LEDs makes it difficult for the surrounded LED to have a high copper area.

(16) In this case, even the LEDs which are surrounded by many other LEDs have a high copper area, since the rest of the LEDs are far enough to leave the surrounded LED a copper area which is more than 3 times the case surface. In this example, the case surface is 2.56 mm.sup.2, since the case is a square with a side of 1.6 mm. The copper area surrounding the central LED 20c, which is the LED with the lowest copper area, is 8 mm.sup.2, which is far more than the surrounded LEDs present in lighting devices known in the state of the art. In this case, this copper area is divided into two copper area portions 51, 52. This high value of copper area is very important for a good thermal behaviour of the LED.

(17) As a consequence, since all the LEDs 2 are properly cooled by the corresponding copper area, its current value may be increased and therefore, the same flux value may be obtained with a smaller number of LEDs, thus reducing the cost and manufacturing time.

(18) FIG. 3 shows an automotive lighting device 1 according to the invention installed in an automotive vehicle 100, wherein the light sources provide light to a light guide 4 to perform both a turning indicator functionality and a day running light functionality.