Light guide

Abstract

This invention relates to an optical guide comprising a light input surface, a longitudinal path, and a lateral surface, wherein at least a portion of the lateral surface is configured as a light emitting surface, wherein a first optical guide segment and a second optical guide segment include a plurality of light reorientation elements configured to reorient light toward the light emitting surface, wherein the light emitting surface is a curved surface having a primary focal line, wherein each light reorientation element has a certain cutting depth that increases along the longitudinal path, wherein the light emitting surface of the second optical guide segment has a protrusion having a secondary focal line closer to the light emitting surface than the primary focal line, wherein the light reorientation elements of the first optical guide segment intersect the primary focal line, and wherein the light reorientation elements of the second optical guide segment intersect both the primary and secondary focal lines.

Description

Technical Field

[0001] This invention relates to a light guide configured to receive and emit light from a light source, wherein the light guide includes:

[0002] - A light input surface configured to receive light from a light source, wherein the light enters a light guide via the light input surface and propagates along a longitudinal path through at least a portion of the light guide, the longitudinal path being oriented substantially along the longitudinal length of the light guide.

[0003] - A lateral surface extending from the light input surface along the longitudinal length of the light guide, wherein the lateral surface defines the external shape of the light guide, and wherein at least a portion of the lateral surface is configured as a light emitting surface through which light exits the light guide.

[0004] - A first light guide segment and a second light guide segment, wherein the first light guide segment is closer to the light input surface than the second light guide segment, wherein the first and second light guide segments include a plurality of light reorientation elements arranged coherently along the longitudinal length of the light guide and opposite to the light emission surface, wherein the light reorientation elements are configured to reorient at least a portion of the light propagating along the longitudinal path through the light guide toward the light emission surface, wherein the reoriented light exits the light guide through the light emission surface, wherein the light emission surface is a curved surface having a principal focal line oriented substantially along the longitudinal length of the light guide.

[0005] Each light redirection element includes a first surface and a second surface. The first surface extends radially substantially toward the longitudinal axis of the light guide, and the second surface is oriented at an angle to the first surface. The first and second surfaces form a substantially wedge-shaped recess. The second surface is configured to redirect incident light toward a light exiting surface. The impact light is at least a portion of the light propagating along a longitudinal path through the light guide.

[0006] Each light reorientation element has a certain cutting depth, which is defined as a radial range of the first surface facing the longitudinal axis of the light guide. The cutting depth increases along the longitudinal length of the light guide and along the longitudinal path. The cutting depth increases at a rate that compensates for the loss of light flux along the longitudinal path, such that the light leaving the light guide through the light exiting surface has substantially equal light flux along the light exiting surface.

[0007] The present invention also relates to an illumination device for a vehicle headlight, the illumination device including a light guide and a light source, the light source being configured to illuminate the light guide through a light input surface of the light guide.

[0008] The present invention also relates to vehicle headlights that include light guides or lighting devices. Background Technology

[0009] Optical guides are known in the prior art. Typically, optical redirection elements, such as optical output connectors like output prisms, have a certain cut depth, which needs to increase along the longitudinal length of the optical guide. This increase in cut depth is necessary to provide light output beyond the entire length of the optical guide. A larger cut depth results in a larger optical redirection surface, and therefore, the amount of light reduction at the ends of the optical guide is compensated by the larger optical redirection surface.

[0010] The disadvantage of increasing the cut depth is that it results in uneven light output across the light emitting surface. In particular, a portion of the light emitting surface corresponding to the deeper cut depth at the end / rear portion of the light guide shows dots or lines that are less bright compared to the portion of the light guide with a smaller cut depth (i.e., the portion of the light emitting surface relatively close to the light source).

[0011] Therefore, the purpose of this invention is to improve the light output of the light emitting surface of the light guide.

[0012] This objective is achieved by the optical guide according to claim 1. Preferred embodiments are described in the dependent claims. Summary of the Invention

[0013] According to a first aspect of the invention, the light-emitting surface of the second light-guiding segment has a protrusion having a substantially arcuate cross-section, wherein the protrusion is substantially positioned opposite to the light-reorienting element, wherein the protrusion has a longitudinal length substantially parallel to the longitudinal axis of the light guide, and wherein the protrusion has a secondary focal line closer to the light-emitting surface than the primary focal line.

[0014] In this configuration, the second surfaces of the light redirection elements in the first light guiding section are arranged such that each second surface intersects the principal focal line of the light emitting surface.

[0015] In this section, the second surface of the light reorientation element of the second light guide segment is arranged such that each second surface intersects the primary focal line of the light emitting surface and the secondary focal line of the protrusion.

[0016] This has the following advantages: the amount of light emitted along the entire light-emitting surface is uniform. A uniform amount means that the luminous flux passing through the entire light-emitting surface is essentially constant per unit area. This means that an observer will not see brighter or darker points along the longitudinal length of the light-emitting surface or the light guide, respectively.

[0017] Preferably, the light leaving the second light guide section is substantially redirected by the entire second surface of the corresponding light redirection element.

[0018] Preferably, since the second surface of the light redirection element in the second light guide section is arranged along the secondary focal line of the protrusion and the primary focal line of the light emitting surface, a strong and uniform light distribution can be emitted through the light guide. This can produce a particularly uniform light impression for the observer of the light guide.

[0019] Preferably, the primary focal line and / or secondary focal line follow the form / curvature of the optical guide.

[0020] Preferably, the secondary focal line is formed by or corresponds to the surface of the protrusion. The protrusion can be substantially constructed as a lens, such as a cylindrical lens, wherein the secondary focal line can be the focal line of the lens.

[0021] Preferably, since each second surface intersects the principal focal line of the light-emitting surface and the secondary focal line of the protrusion, essentially all the light incident on the second surface (i.e., the light in the region of the principal focal line and the light in the region of the secondary focal line) is projected through the light-emitting surface and the protrusion of the light-emitting surface, respectively. This advantageously produces a strong and uniform light distribution emitted by the light guide. The longitudinal axis of the light guide may also be referred to as the central axis. In the context of this disclosure, a cross-section refers to a cut along a plane perpendicular to the longitudinal length / path or longitudinal axis of the light guide.

[0022] Advantageously, the cutting depth of the first surface of the first light guide segment and the angle between the first and second surfaces cause the second surface of the first light guide segment to intersect with the principal focal line, wherein the cutting depth of the first surface of the second light guide segment and the angle between the first and second surfaces cause the second surface of the second light guide segment to intersect with both the principal and secondary focal lines. This has the advantage that the light emitting surfaces of the first and second light guide segments emit a strong, focused light distribution.

[0023] Preferably, since the second surface of the second light guide section intersects the primary focal line and the secondary focal line, essentially all the light incident on the second surface is projected through the light emitting surface and the protrusion of the light emitting surface.

[0024] Advantageously, the angle between the first and second surfaces is between 1° and 90°, preferably between 15° and 75°, and particularly between 25° and 65°. This angle can be constant along the longitudinal length of the light guide. Alternatively, this angle can be reduced along the longitudinal length of the light guide, thereby creating a larger possible area for supplying light impact.

[0025] Advantageously, the opposite side of this angle lies on the lateral surface, wherein the light redirection element is preferably a reflecting prism. Reflecting prisms have the advantage of being inexpensive to manufacture because they can be formed by cutting a wedge-shaped recess in the lateral surface of the light guide.

[0026] Advantageously, the primary and / or secondary focal lines are substantially parallel to the longitudinal axis of the optical guide. If the optical guide has curvature, the primary and / or secondary focal lines can preferably follow that curvature.

[0027] Advantageously, the optical guide is substantially cylindrical in shape with a first cylindrical radius, wherein the protrusion is substantially cylindrical in shape with a second cylindrical radius, wherein the first cylindrical radius is larger than the second cylindrical radius. Preferably, the first cylindrical radius of the optical guide is at least 1.5 times, preferably more than 2 times, particularly more than 3 times or more than 4 times larger than the second cylindrical radius of the protrusion.

[0028] Advantageously, the protrusion is substantially cylindrical in shape with a cylindrical radius, wherein the cylindrical radius increases, preferably continuously, along the longitudinal path. This has the advantage of emitting particularly uniform light distribution from the light-emitting surface of the light guide, even at the distal end of the light guide, i.e., the distal end portion of the light guide located at the light source.

[0029] Advantageously, the protrusion is substantially cylindrical in shape with a cylindrical radius and a cylindrical axis, wherein the cylindrical radius is constant along the longitudinal path, and wherein the perpendicular distance between the cylindrical axis of the protrusion and the central axis of the light guide increases, preferably continuously, along the longitudinal path. This can be an alternative to an ever-increasing cylindrical radius and has the same advantage of emitting a particularly uniform light distribution from the light-emitting surface of the light guide along the entire longitudinal length.

[0030] Advantageously, the light guide is a transparent solid body, wherein the light redirection element is a recess in the lateral surface of the solid body. This has the advantage of particularly low production cost for the light guide.

[0031] Advantageously, the protrusion extends across 10% to 25% of the light emitting surface of the second light guide section. This has the advantage that a particularly uniform light distribution is emitted from the entire light emitting surface of the light guide, and in particular, substantially equal amounts of light can be emitted from the proximal and distal ends of the light guide, so that there are no darker or brighter areas along the entire light emitting surface.

[0032] Advantageously, the protrusion is positioned opposite to the light redirection element of the second light guide section. Preferably, the protrusion is positioned opposite to the light redirection element of the second light guide section in diameter. This has the advantage that the light redirection element directly redirects a larger amount of light directly to both the light emitting surface and the protrusion on the light emitting surface.

[0033] Advantageously, the protrusion has a longitudinal length that is substantially parallel to the longitudinal length of the optical guide.

[0034] Advantageously, the protrusion has a cross-section in the shape of a paraboloid of revolution, wherein the paraboloid of revolution preferably has a parabolic radius, wherein the parabolic radius increases along the longitudinal path, preferably continuously.

[0035] According to another aspect of the present invention, an illumination device for a vehicle headlight is provided, the illumination device comprising a light guide according to the present invention.

[0036] According to another aspect of the invention, a vehicle headlight is provided, the vehicle headlight comprising a light guide or lighting device according to the invention. Attached Figure Description

[0037] In the following description, to further illustrate the invention, illustrative and non-limiting embodiments as shown in the accompanying drawings, in which:

[0038] Figure 1 This illustrates a prior art optical guide;

[0039] Figure 2 It shows that according to Figure 1 Detailed view of the optical guide component;

[0040] Figure 3 A first embodiment of the optical guide according to the present invention is shown;

[0041] Figure 4 A cross-section of the first optical guide segment of the optical guide according to the present invention is shown;

[0042] Figure 5 A cross-section of the second optical guide segment of the optical guide according to the present invention is shown;

[0043] Figure 6 A detailed view of a first embodiment of the optical guide is shown;

[0044] Figure 7 Detailed views of a second embodiment of the optical guide are shown; and

[0045] Figure 8 It shows that according to Figure 7 Another view of the optical guide. Detailed Implementation

[0046] In the following figures, unless otherwise explicitly depicted, the same reference numerals refer to the same features. Reference numerals are for informational purposes only and do not define the scope of protection.

[0047] For simplicity, elements that are not essential to the present invention are not shown in the accompanying drawings.

[0048] Figure 1 A light guide 1 according to the prior art is shown. The light guide 1 is configured to receive and emit light from a light source 8. The light guide 1 includes a light input surface 2 configured to receive light from the light source 8. The light enters the light guide 1 via the light input surface 2 and propagates along a longitudinal path 3 through at least a portion of the light guide 1. The longitudinal path 3 is oriented substantially along the longitudinal length of the light guide 1. The light guide 1 has a lateral surface 4 extending from the light input surface 2 along the longitudinal length of the light guide 1. The lateral surface 4 defines the external shape of the light guide 1. At least a portion of the lateral surface 4 is configured as a light exit surface 4a through which light exits the guide 1.

[0049] The light guide 1 has a first light guide section 1a and a second light guide section 1b, wherein the first light guide section 1a is closer to the light input surface 2 than the second light guide section 1b. The first light guide section 1a and the second light guide section 1b include a plurality of light redirection elements 5, which are arranged continuously along the longitudinal length of the light guide 1 and opposite to the light emission surface 4a.

[0050] Figure 2 A detailed view of the light guide 1 is shown. The light redirection element 5 is configured to redirect at least a portion of the light propagating along the longitudinal path 3 through the light guide 1 toward the light exiting surface 4a. The redirected light exits the light guide 1 through the light exiting surface 4a.

[0051] Each light redirection element 5 includes a first surface 5a and a second surface 5b, the first surface 5a extending radially substantially toward the longitudinal axis 7 of the light guide 1, and the second surface 5b oriented at an angle α to the first surface 5a. The first surface 5a and the second surface 5b form a substantially wedge-shaped recess. The second surface 5b is configured to redirect incident light toward the light exiting surface 4a, wherein the incident light is at least a portion of the light propagating along the longitudinal path 3 through the light guide 1.

[0052] The angle α between the first surface 5a and the second surface 5b can be between 1° and 90°, preferably between 15° and 75°, and particularly between 25° and 65°. The opposite side of angle α is preferably located on the lateral surface 4. Preferably, the light redirection element 5 is a reflecting prism.

[0053] Each optical reorientation element 5 has a certain cutting depth d (see details below) Figure 4 and Figure 5 The cutting depth d is defined as the radial range of the first surface 5a toward the longitudinal axis 7 of the light guide 1. The cutting depth d increases along the longitudinal length of the light guide 1 and along the longitudinal path 3. The cutting depth d increases at a rate that compensates for the loss of luminous flux along the longitudinal path 3, such that the light exiting the light guide 1 through the light emitting surface 4a has substantially equal luminous flux along the light emitting surface 4a.

[0054] Figure 3 A first embodiment of the light guide according to the present invention is shown. In the illustrated embodiment, the light guide 1 has a protrusion 6 on its light emitting surface 4a, the protrusion 6 being closer to the end portion of the light guide 1, i.e., the second light guide segment 1b. It will be apparent to those skilled in the art that two light guides 1 may also be present, for example, two light guides 1 stacked vertically on top of each other. The present invention is not limited to a single light guide.

[0055] The light-emitting surface 4a of the light guide 1 is a curved surface having a main focal line F1 oriented substantially along the longitudinal length of the light guide 1.

[0056] Figure 4 A cross-section of the first light guiding segment 1a of the light guiding component 1 is shown. It can be seen that the light reorientation element 5 in the first light guiding segment 1a has a certain cutting depth d.

[0057] Figure 5 A cross-section of the second light guide segment 1b of the light guide 1 is shown. It can be seen that the light reorientation element 5 in the second light guide segment 1b has a larger cutting depth d compared to the light reorientation element 5 in the first light guide segment 1a.

[0058] The light-emitting surface 4a of the second light guide section 1b has a protrusion 6, which has a substantially arc-shaped cross-section. The protrusion 6 is positioned substantially opposite to the light redirection element 5. The protrusion 6 has a longitudinal length substantially parallel to the longitudinal axis 7 of the light guide 1, wherein the protrusion 6 has a secondary focal line F2, which is closer to the light-emitting surface 4a than the primary focal line F1 (see...). Figure 4 and Figure 5The primary focal line F1 and / or secondary focal line F2 are substantially parallel to the longitudinal axis 7 of the light guide 1. The protrusion 6 may extend 10% to 25% across the light emitting surface 4a of the second light guide segment 1b. The protrusion 6 may have a longitudinal length substantially parallel to the longitudinal length of the light guide 1.

[0059] The second surface 5b of the light reorientation element 5 of the first light guiding component section 1a is arranged such that each second surface 5a intersects the principal focal line F1 of the light emitting surface 4a.

[0060] The second surface 5b of the light reorientation element 5 in the second light guiding section 1b is arranged such that each second surface 5b intersects the primary focal line F1 of the light emitting surface 4a and the secondary focal line F2 of the protrusion 6.

[0061] As in Figure 4 As can be seen from the image, the cutting depth d of the first surface 5a of the first optical guide section 1a (and / or the angle α between the first surface 5a and the second surface 5b) causes the second surface 5b of the first optical guide section 1a to intersect with the main focal line F1.

[0062] As in Figure 5 As can be seen, the cutting depth d of the first surface 5a of the second light guide segment 1b (and / or the angle α between the first surface 5a and the second surface 5b) causes the second surface 5b of the second light guide segment 1b to intersect with the primary focal line F1 and the secondary focal line F2. Therefore, all the light incident on the first surface 5a of the second light guide segment 1b can be uniformly projected through the light emitting surface 4a. The protrusion 6 can be positioned opposite to the light redirection element 5 of the second light guide segment 1b.

[0063] In the illustrated embodiment, the light guide 1 is substantially cylindrical in shape with a first cylindrical radius. The protrusion 6 is substantially cylindrical in shape with a second cylindrical radius, wherein the first cylindrical radius is larger than the second cylindrical radius.

[0064] exist Figure 6 In the illustrated embodiment, the protrusion 6 is essentially cylindrical in shape with a cylindrical radius, wherein the cylindrical radius increases, preferably continuously, along the longitudinal path 3. Since the radius r2 is greater than the radius r1, this increase in radius... Figure 6 As shown in the image.

[0065] exist Figure 7 and Figure 8 In the illustrated embodiment, the protrusion 6 is essentially cylindrical in shape with a cylindrical radius and a cylindrical axis, wherein the cylindrical radius is constant along the longitudinal path 3. The vertical distance d3 (normal distance) between the cylindrical axis of the protrusion 6 and the central axis of the optical guide 1 increases along the longitudinal path 3, preferably continuously.

[0066] Preferably, the light guide 1 is a transparent solid body, wherein the light redirection element 5 is a recess in the lateral surface 4 of the solid body.

[0067] In an alternative embodiment, the protrusion 6 may have a cross-section in the shape of a paraboloid of revolution. Preferably, the paraboloid of revolution has a parabolic radius, wherein the parabolic radius increases, preferably continuously, along the longitudinal path 3.

[0068] Of course, the present invention is not limited to the examples given in this specification, which merely illustrate embodiments that can be implemented by those skilled in the art in light of this disclosure.

Claims

1. A light guide (1) configured to receive and emit light from a light source (8), wherein, The optical guide (1) includes: A light input surface (2) is configured to receive light from a light source (8), wherein the light enters the light guide (1) via the light input surface (2) and propagates along a longitudinal path (3) through at least a portion of the light guide (1), the longitudinal path (3) being oriented substantially along the longitudinal length of the light guide (1). A lateral surface (4) extends from the light input surface (2) along the longitudinal length of the light guide (1), wherein the lateral surface (4) defines the external shape of the light guide (1), and wherein at least a portion of the lateral surface (4) is configured as a light emitting surface (4a) through which light exits the light guide (1). A first light guide segment (1a) and a second light guide segment (1b), wherein the first light guide segment (1a) is closer to the light input surface (2) than the second light guide segment (1b), wherein the first light guide segment (1a) and the second light guide segment (1b) include a plurality of light redirection elements (5), the light redirection elements (5) being arranged continuously along the longitudinal length of the light guide (1) and connected to the light emitting surface (4). a) Relatively, wherein the light reorientation element (5) is configured to reorient at least a portion of the light propagating along the longitudinal path (3) through the light guide (1) toward the light emitting surface (4a), wherein the reoriented light exits the light guide (1) through the light emitting surface (4a), wherein the light emitting surface (4a) is a curved surface having a principal focal line (F1) oriented substantially along the longitudinal length of the light guide (1). Each light redirection element (5) includes a first surface (5a) and a second surface (5b), the first surface (5a) extending radially substantially toward the longitudinal axis (7) of the light guide (1), and the second surface (5b) oriented at an angle (α) to the first surface (5a), wherein the first surface (5a) and the second surface (5b) form a substantially wedge-shaped recess, wherein the second surface (5b) is configured to redirect incident light toward the light emitting surface (4a), wherein the incident light is at least a portion of the light propagating along the longitudinal path (3) through the light guide (1). Each light redirection element (5) has a certain cutting depth (d), which is defined as the radial range of the first surface (5a) toward the longitudinal axis (7) of the light guide (1). The cutting depth (d) increases along the longitudinal length of the light guide (1) and along the longitudinal path (3). The cutting depth (d) increases at a rate that compensates for the loss of luminous flux along the longitudinal path (3), such that the light exiting the light guide (1) through the light emitting surface (4a) has substantially equal luminous flux along the light emitting surface (4a). Its features are, The light emitting surface (4a) of the second light guide segment (1b) has a protrusion (6) having a substantially arc-shaped cross-section, wherein the protrusion (6) is substantially positioned opposite to the light redirection element (5), wherein the protrusion (6) has a longitudinal length substantially parallel to the longitudinal axis (7) of the light guide (1), and wherein the protrusion (6) has a secondary focal line (F2) that is closer to the light emitting surface (4a) than the primary focal line (F1). In this embodiment, the second surface (5b) of the light redirection element (5) of the first light guiding component segment (1a) is arranged such that each second surface (5b) intersects the principal focal line (F1) of the light emitting surface (4a). In this embodiment, the second surface (5b) of the light reorientation element (5) of the second light guide segment (1b) is arranged such that each second surface (5b) intersects the primary focal line (F1) of the light emitting surface (4a) and the secondary focal line (F2) of the protrusion (6).

2. The optical guide (1) according to claim 1, wherein, The cutting depth (d) of the first surface (5a) of the first light guide segment (1a) and the angle (α) between the first surface (5a) and the second surface (5b) are such that the second surface (5b) of the first light guide segment (1a) intersects the main focal line (F1), wherein the cutting depth (d) of the first surface (5a) of the second light guide segment (1b) and the angle (α) between the first surface (5a) and the second surface (5b) are such that the second surface (5b) of the second light guide segment (1b) intersects the main focal line (F1) and the secondary focal line (F2).

3. The optical guide (1) according to any one of claims 1 to 2, wherein, The angle (α) between the first surface (5a) and the second surface (5b) is between 1° and 90°.

4. The optical guide (1) according to any one of claims 1 to 2, wherein, The angle (α) between the first surface (5a) and the second surface (5b) is between 15° and 75°.

5. The optical guide (1) according to any one of claims 1 to 2, wherein, The angle (α) between the first surface (5a) and the second surface (5b) is between 25° and 65°.

6. The optical guide (1) according to any one of claims 1 to 2, wherein, The opposite side of the angle (α) lies on the lateral surface (4), wherein the light redirection element (5) is a reflecting prism.

7. The optical guide (1) according to any one of claims 1 to 2, wherein, The primary focal line (F1) and / or the secondary focal line (F2) are substantially parallel to the longitudinal axis (7) of the light guide (1).

8. The optical guide (1) according to any one of claims 1 to 2, wherein, The light guide (1) is substantially cylindrical in shape with a first cylindrical radius, wherein the protrusion (6) is substantially cylindrical in shape with a second cylindrical radius, wherein the first cylindrical radius is greater than the second cylindrical radius.

9. The optical guide (1) according to any one of claims 1 to 2, wherein, The protrusion (6) is essentially cylindrical in shape with a cylindrical radius, wherein the cylindrical radius increases along the longitudinal path (3).

10. The optical guide (1) according to any one of claims 1 to 2, wherein, The protrusion (6) is essentially cylindrical in shape with a cylindrical radius and a cylindrical axis, wherein the cylindrical radius is constant along the longitudinal path (3), and wherein the vertical distance between the cylindrical axis of the protrusion (6) and the central axis of the light guide increases along the longitudinal path (3).

11. The optical guide (1) according to any one of claims 1 to 2, wherein, The light guide (1) is a transparent solid body, wherein the light redirection element (5) is a recess in the lateral surface (4) of the solid body.

12. The optical guide (1) according to any one of claims 1 to 2, wherein, The protrusion (6) extends 10% to 25% across the light emitting surface (4a) of the second light guide section (1b).

13. The optical guide (1) according to any one of claims 1 to 2, wherein, The protrusion (6) is positioned opposite to the light redirection element (5) of the second light guide section (1b).

14. The optical guide (1) according to any one of claims 1 to 2, wherein, The protrusion (6) has a longitudinal length that is substantially parallel to the longitudinal length of the light guide (1).

15. The optical guide (1) according to any one of claims 1 to 2, wherein, The protrusion (6) has a cross-section in the shape of a parabolic surface of revolution, wherein the parabolic surface of revolution has a parabolic radius, wherein the parabolic radius increases along the longitudinal path (3).

16. An illumination device for a vehicle headlight, the illumination device comprising a light guide (1) according to any one of claims 1 to 15 and a light source (8), the light source (8) being configured to illuminate the light guide (1) via the light input surface (2) of the light guide (1).

17. A vehicle headlight comprising a light guide (1) according to any one of claims 1 to 15 or a lighting device according to claim 16.

Images