Optical conductor and lighting system

Abstract

An optical conductor has several spherically curved light-extraction areas on its surface that are arranged in spaced relationship to one another and have a particular height (h) and a particular radius (R) of surface curvature, wherein h/R ratios of the respective height to the respective radius of all light-extraction areas are substantially equal and lie within a range of 0.1 to 0.45. A lighting system comprises one or more optical conductors and one or more light sources for irradiation of at least one light-injection area of the optical conductor, wherein useful light radiated from the front of the optical conductor can be emitted unscattered from the lighting system and/or interference light emitted outside of a useful light path is absorbable by the lighting system. Some embodiments may be particularly applicable in vehicle lighting systems.

Claims

1. An optical conductor configured to receive light generated by a light source and to conduct the generated light along a length of the optical conductor, the optical conductor comprising: a plurality of spherically curved light-extraction areas arranged on a surface of the optical conductor in spaced relationship to one another, wherein each of the plurality of spherically curved light-extraction areas is located a corresponding distance from the light source, and wherein each of the plurality of spherically curved light- extraction areas has height (h) and a radius (R) of surface curvature, wherein: h/R ratios of respective height to respective radius of all of the plurality of light-extraction areas are substantially equal, the h/R ratios lie within a range of 0.1 to 0.45, the radius lies within a range of 0.1 mm to 1 mm and the height lies within a range of 0.01 mm to 1 mm.

2. The optical conductor according to claim 1, wherein respective heights of the plurality of light-extraction areas increase with increasing distance from a light-injection area of the optical conductor.

3. The optical conductor according to claim 1, wherein the h/R ratios lie within a range of 0.25 to 0.35.

4. The optical conductor according to claim 1, wherein respective heights of two or more light-extraction areas of the plurality of light-extraction areas differ.

5. The optical conductor according to claim 1, wherein at least one light-extraction area of the plurality of light-extraction areas has a spherical cap shape.

6. The optical conductor according to claim 1, wherein at least one light-extraction area of the plurality of light-extraction areas has a spherical line shape.

7. The optical conductor according to claim 1, wherein the optical conductor is provided in the shape of a plate with a back and a front, the front being configured to extract useful light, and the plurality of light-extraction areas being provided on the front and/or on the back.

8. The optical conductor according to claim 1, wherein the plurality of light-extraction areas are arranged for uniformly bright radiation of useful light over an area.

9. The optical conductor according to claim 1, wherein the plurality of light-extraction areas are configured to provide uniformly bright radiation of useful light over an area.

10. The optical conductor according to claim 1, wherein the h/R ratios are greater than or equal to 0.3.

11. The optical conductor according to claim 1, wherein the h/R ratios are less than or equal to 0.4.

12. The optical conductor according to claim 1, wherein all of the plurality of light-extraction areas have a spherical cap shape.

13. The optical conductor according to claim 1, wherein all of the plurality of light-extraction areas have a spherical line shape.

14. The optical conductor according to claim 1, further comprising a plurality of rows of the plurality of light-extraction areas, the plurality of light-extraction areas of a row of the plurality of rows being aligned in a transverse direction, the transverse direction being perpendicular to a longitudinal direction of the optical conductor, wherein respective heights of the plurality of light-extraction areas increase with increasing distance in the longitudinal direction from a light-injection area of the optical conductor.

15. An optical conductor configured to receive light generated by a light source and to conduct the generated light along a length of the optical conductor, the optical conductor comprising: a plurality of spherically curved light-extraction areas arranged on a surface of the optical conductor in spaced relationship to one another, wherein each of the plurality of spherically curved light-extraction areas is located a corresponding distance from the light source, and wherein each of the plurality of spherically curved light- extraction areas has a height (h) and a radius (R) of surface curvature, wherein: h/R ratios of respective height to respective radius of all of the plurality of light-extraction areas are substantially equal, the h/R ratios lie within a range of 0.1 to 0.45, the height (h) of each spherically curved light-extraction area along the length of the optical conductor increases according to the distance of the respective spherically curved light-extraction area from the light source, the radius (r) of each spherically curved light-extraction area along the length of the optical conductor increases according to the distance of the respective spherically curved light-extraction area from the light source, the spherically curved light-extraction areas, with the increasing height (h) and increasing radius (r), along the length are configured to have the same h/R ratio, and the radius lies within a range of 0.1 mm to 1 mm and the height lies within a range of 0.01 to 1 mm.

16. The optical conductor according to claim 15, wherein the height and radius continually increases according to the distance.

17. The optical conductor according to claim 15, wherein the h/R ratios lie within a range of 0.25 to 0.35.

18. The optical conductor according to claim 15, wherein the h/R ratios are greater than or equal to 0.3.

19. The optical conductor according to claim 15, wherein the h/R ratios are less than or equal to 0.4.

20. The optical conductor according to claim 15, wherein the light extraction areas are arranged in differently shaped groups.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above and other aspects of the present disclosure will become more apparent by describing exemplary embodiments in detail below with reference to the accompanying drawings, in which:

(2) FIG. 1 shows a lateral cross-section of a lighting system with an optical conductor in accordance with a first embodiment of the present disclosure having several light-extraction areas;

(3) FIG. 2 shows a detail of an optical conductor according to FIG. 1 in the vicinity of a light-extraction area;

(4) FIG. 3 shows a polar diagram of a light intensity distribution for an h/R ratio of 0.3;

(5) FIG. 4 shows a polar diagram of a light intensity distribution for an h/R ratio of 0.1;

(6) FIG. 5 shows a polar diagram of a light intensity distribution for an h/R ratio of 0.5;

(7) FIG. 6 shows a plan view of an optical conductor according to a second embodiment of the present disclosure;

(8) FIG. 7 shows a plan view of an optical conductor according to a third embodiment of the present disclosure; and

(9) FIG. 8 shows a plan view of an optical conductor according to a fourth embodiment of the present disclosure.

(10) FIG. 9 shows differing heights of two or more light-extraction areas of the plurality of light extracting areas;

(11) FIG. 10 shows radius of spherical curved light extraction areas along the length of the curved light-extraction area and along the length of the optical conductor increasing with distance from the light source; and

(12) FIG. 11 shows respective heights of the plurality of light-extraction areas increasing with distance from a light-injection area of the optical conductor.

(13) The figures are schematic representations and are used purely to explain certain exemplary embodiments. Similar elements, or those that work in a similar way, are provided with the same reference characters throughout.

DETAILED DESCRIPTION

(14) As used throughout the present disclosure, the expression A and/or B shall mean A alone, B alone, or A and B together. Expressions such as at least one of do not necessarily modify an entirety of a following list and do not necessarily modify each member of the list, such that at least one of A, B, and C should be understood as including only one of A, only one of B, only one of C, or any combination of A, B, and C. Furthermore, the conjunctive term or shall be construed in its broadest sense, for example, meaning that only one of the listed elements need be present, and that additional elements may also be present.

(15) FIG. 1 shows a lateral cross-section of a lighting system 1 with a plate-shaped optical conductor 2 in accordance with a first embodiment. The optical conductor 2 has a lateral surface 3 serving as a light-injection surface to couple in light L. The light L in this case is generated, for example, by one or more LEDs 4 aimed at the lateral surface 3. The light L coupled in at the lateral surface 3 spreads by total internal reflection in the optical conductor 2. When the light L strikes a light-extraction area 5, it is deflected in such a manner that it can subsequently exit the optical conductor 2. The light-extraction areas 5 thus act as interference points in the light conduction. The light-extraction areas 5 here are arranged on a back 6 of the optical conductor 2.

(16) A portion of the light L deflected from the light-extraction areas 5 exits the optical conductor 2 at the back 6. Some of this light may be interference light S. Interference light S may not be further used. For example, it can be absorbed by an absorbent surface (not shown) and/or it can be reflected by a reflecting surface (not shown) and, where applicable, it can then be at least partly reused as useful light. Another portion of the light L deflected from the light-extraction areas 5 exits the optical conductor 2 at a front 7 and, being useful light N, it is further used.

(17) As shown in FIG. 2 as a detailed view, the light-extraction areas 5 may be embodied as spherically curved protrusions with a spherical cap-shaped surface. The light-extraction areas 5 have a height h. A constant radius R may be assigned to the spherical cap-shaped surface. In the first embodiment, all light-extraction areas 5 have an equal h/R ratio of 0.3.

(18) The light-extraction areas 5 shown in FIG. 1 may have different heights h and/or radii R, as long as the same h/R ratio is maintained. In particular, light-extraction areas 5 spaced farther away from the lateral surface 3 may have a larger height h and a larger radius to locally radiate a larger quantity of light. Accordingly, a particular quantity of light radiated from the light-extraction areas 5 can be kept constant, thereby facilitating uniformly bright emission of useful light N over the entire front 7.

(19) As an alternative to a spherical cap-shaped surface, the light-extraction areas 5 may have a respective spherical line shape in which they extend longitudinally in a direction perpendicular to an image plane of the optical conductor 2.

(20) Alternatively or additionally, light-extraction areas 5 may be provided on the front 7.

(21) The lighting system 1, for example, may be external vehicle lighting such as a headlight or internal vehicle lighting such as decor illumination, or it may be a component thereof.

(22) In particular, following its emission the useful light N may be radiated unscattered out of the lighting system 1 from the front 7. A dissipating layer may therefore be omitted. Accordingly, provided that the optical conductor 2 is visible, the light-extraction areas 5 may be viewed from the outside. The light-extraction areas 5 may then be used as design elements.

(23) FIG. 3 shows a polar diagram of a light intensity distribution Iv of the useful light N across a polar angle for an h/R ratio of 0.3. At h/R=0.3, the useful light N is emitted in a relatively large solid angle range. Furthermore, useful light N is emitted in a direction x that is perpendicular to the front 7.

(24) FIG. 4 shows a polar diagram analogous to FIG. 3 for an h/R ratio of 0.1. Compared to the h/R ratio of 0.3, the emission takes place in a narrower solid angle range. The light radiation in the perpendicular direction x is virtually zero.

(25) FIG. 5 shows a polar diagram analogous to FIG. 3 for an h/R ratio of 0.5. Compared to the h/R ratio of 0.1, the emission takes place in an even more narrow solid angle range with a primary direction of radiation that deviates even more strongly from the perpendicular direction x. The light radiation along the perpendicular direction x is very low.

(26) FIG. 6 shows a plan view of the back 6 of an optical conductor 8 according to a second embodiment. In optical conductor 8, the light-extraction areas 5 are arranged in transverse rows 9 that are uniformly spaced in a longitudinal direction of the optical conductor 8. The light-extraction areas 5 thereby form a rectangular matrix-shaped surface pattern. The light-extraction areas 5, for example, may have an equal height h within each of the transverse rows 9. The height h of the light-extraction areas 5 of the individual transverse rows 9 may increase with increasing distance from the lateral surface 3. For example, height h of the light-extraction areas 5 in an individual transverse row 9 may increase relative to an adjacent transverse row 9, or in blocks of every n>=2 transverse rows 9, etc.

(27) Alternatively, the light-extraction areas 5 may be arranged in groups. The groups may be distributed over the optical conductor in a matrix-like manner.

(28) FIG. 7 shows a plan view of an optical conductor 10 according to a third embodiment. The optical conductor 10 has the light-extraction areas 5 arranged in diamond-shaped groups 11.

(29) FIG. 8 shows a plan view of an optical conductor 12 according to a fourth embodiment. The structure of the optical conductor 12 is similar to that of the optical conductor 10. However, the light-extraction areas 5 are now arranged in differently shaped groups 13, 14.

(30) FIGS. 9-11 depict respective heights of the plurality of light-extraction areas increasing with increasing distance from a light-injection area of the optical conductor. Additionally, these figures depict respective heights of two or more light-extraction areas of the plurality of light-extraction areas along with the radius (r) of each spherically curved light-extraction area along the length of the curved light-extraction area and along the length of the optical conductor increasing according to the distance from the light source of the respective spherically curved light-extraction area(s). Still further, the spherically curved light-extraction areas, with the increasing height (h) and increasing radius (r), along the length configured to have the same h/R ratio is depicted.

(31) It will be appreciated that the present disclosure is not limited to the embodiments illustrated.

(32) In general, by a, an, the, etc., a singular or plural may be understood, particularly in the sense of at least one or one or more, etc., as long as this is not explicitly ruled out, for instance by the expression exactly one etc.

(33) Also, a number can indicate precisely the given number or it can also include a customary tolerance range, as long as this is not expressly ruled out.

(34) Having described aspects of the present disclosure in detail, it will be apparent that further modifications and variations are possible without departing from the scope of aspects of the present disclosure as defined in the appended claims. As various changes could be made in the above constructions, products, and methods without departing from the scope of aspects of the present disclosure, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

LIST OF REFERENCE CHARACTERS

(35) 1 lighting system 2 optical conductor 3 lateral surface 4 LED 5 light-extraction area 6 back of the optical conductor 7 front of the optical conductor 8 optical conductor 9 transverse row 10 optical conductor 11 group of light-extraction areas 12 optical conductor 13 group of light-extraction areas 14 group of light-extraction areas A detail h height of the light-extraction area Iv light intensity L light of the light-extraction area N useful light R radius S interference light polar angle x perpendicular direction