DE102017119917A1 - Optical fiber arrangement and motor vehicle lighting device with such a light guide arrangement - Google Patents

Abstract

The invention relates to a light guide arrangement (10) for use in a motor vehicle lighting device (1). It comprises a flat lens (11) of a solid transparent material, with two opposite plane-parallel interfaces (18, 20, 19, 21) and a light entry surface (13) on one end face. The light (16) propagates by means of total reflection at the interfaces (18, 20, 19, 21) in the lens (11). By means of decoupling elements (22), the light from the lens (11) is coupled out of the lens (11) via one of the interfaces (18, 20, 19, 21). The lens (11) is subdivided into a coupling-in section (12) and a coupling-out section (15), which run at an angle (α) inclined relative to one another.

Description

The present invention relates to a light guide arrangement for use in a motor vehicle lighting device. The light guide arrangement comprises a flat lens of a solid transparent material. The lens has an upper lid surface, a bottom surface parallel to the lid surface, and an edge surface connecting the lid surface to the bottom surface. A partial region of the edge surface forms a light entry surface of the light disk, via which light can be coupled into the light disk, so that the light propagates by total reflection on the cover surface and the bottom surface in a main propagation direction in the light disk. At least partial regions of the cover surface and / or the bottom surface form a light exit surface of the lens, via which light propagating in the lens emerges from the lens. The exit surface is associated with decoupling elements which decouple light rays impinging on them from the light disc via the exit surface.

Furthermore, the invention relates to a motor vehicle lighting device which comprises a housing with a light exit opening directed in the light exit direction, which is closed by a transparent cover, and a lamp module arranged in the interior of the housing for generating a predetermined luminaire function, in particular a daytime running light or a flashing light.

In the design of headlamps, lighting functions (eg flashing light, position light, daytime running light, tail light, brake light, etc.) are usually regarded as design elements which, in addition to the respective legal requirements and requirements, should also be a succinct signature. Often, there is a desire for illuminated free-form surfaces. However, today's state of the art usually requires a separation of the aesthetically effective surfaces of the optical components, which are necessary for the fulfillment of legal requirements for high-intensity lighting functions such as flashing lights and daytime running lights. Thus, for the actual luminaire function mostly on reflectors, intentional optics (transparent massive body with a light entrance surface, a light exit surface and interfaces between them, whereby a bundling of light is achieved by refraction at the light entrance and exit as well as by total reflection at the interfaces), optical fiber or so-called Slit-Lights (cf. US 2012/0 075 876 A1 ), while for luminous freeform surfaces, concepts are used which produce less directional light distribution and therefore can be used, at best, for dim lighting functions, such as position light or side marker light, or as support for other functions. For this purpose, one often uses so-called light curtains ("light curtain") or frosted discs, which are transilluminated, or into which direct light is coupled.

The present invention has for its object to realize lighting functions with high optical efficiency from extended free-form surfaces. In this way, also bright functions such as daytime running lights and flashing light with acceptable electrical power consumption can be realized.

To solve this problem, it is proposed, starting from the light guide arrangement of the type mentioned above, that a light entry surface comprising the light entry surface relative to the remaining part of the lens, which forms a Auskoppelabschnitt of the lens is an angle (α) kinked, which is smaller than the critical angle of the total reflection in the material of the lens, so that in the coupling coupled largely parallel light beams propagating parallel to the cover surface and the bottom surface of the coupling section in this, in the main propagation direction over a length (l) to the adjacent to the coupling section Cover surface or bottom surface of Auskoppelabschnitts make that the decoupling in the main propagation direction have an extension (a), that in the decoupling so many decoupling elements are arranged that the sum of the expansion of all decoupling i n the main propagation direction is greater than or equal to the length (l), wherein outcoupling elements, which are arranged in the main propagation direction other outcoupling elements are arranged such that they are not in the shadow of previous decoupling elements, and that the output surface of the light disc coupled out light alone creates a lighting function of the lighting device.

Further preferred embodiments of the invention can be taken from the dependent subclaims.

One aspect of the present invention is the controlled coupling and decoupling of substantially parallel light beams into a transparent pane whose main plane of extension is curved or arched and which follows a free-form surface. When decoupling the light, a light distribution according to the legal requirements for the respective lamp should be met.

The starting point for the optical waveguide arrangement is a largely parallel light bundle, which, for example, is produced by an attachment optics or a slit light can be and propagated in a transparent optical medium.

According to an advantageous embodiment of the invention, it is proposed that the decoupling elements are arranged on the subregions respectively opposite bottom surface or cover surface and formed such that the decoupling elements deflect at least a portion of the incident light rays on them by total reflection such that for these light rays when hitting the opposite cover surface or bottom surface the conditions for total reflection are no longer satisfied and they emerge from the lens. Alternatively, it is also conceivable that the decoupling elements are arranged in the exit surface forming portions of the bottom surface or cover surface and formed such that at least for a portion of the light beams incident on the decoupling the conditions for total reflection are no longer met and these rays of light when hitting emerge on decoupling from the lens. The angle (α) by which the coupling-in section of the lens is angled relative to the coupling-out section is preferably less than 45 °, particularly preferably less than 10 °.

• 1 eine erfindungsgemäße Kraftfahrzeugbeleuchtungseinrichtung gemäß einer bevorzugten Ausführungsform;
• 2 eine erfindungsgemäße Lichtleiteranordnung, allerdings ohne Auskoppelelemente;
• 3 eine erfindungsgemäße Lichtleiteranordnung gemäß einer ersten bevorzugten Ausführungsform; und
• 4 eine erfindungsgemäße Lichtleiteranordnung gemäß einer weiteren bevorzugten Ausführungsform.

Further features and advantages of the present invention will be explained in more detail below with reference to the figures. Show it:

• 1 a motor vehicle lighting device according to the invention according to a preferred embodiment;
• 2 a light guide arrangement according to the invention, but without coupling elements;
• 3 an inventive light guide assembly according to a first preferred embodiment; and
• 4 an inventive light guide assembly according to another preferred embodiment.

In 1 is a headlight as an example of a lighting device according to the invention 1 shown. This serves primarily to generate a given light distribution. The light distribution can be any desired headlight function, for example dipped beam, high beam, fog light or any adaptive light distribution (eg partial high beam, marker light). In the so-called. Partial remote light, the vehicle, preferably outside of built-up areas, driving with long-distance high-beam, with those areas of the light distribution in which other road users are isolated shadowed or dimmed to prevent dazzling the other road users. The other road users can be detected, for example, by means of a camera in the front region of the vehicle. In the so-called. Marker light is driven permanently with a dimmed light distribution with a horizontal light-dark boundary, with those areas above the light-dark boundary, in which objects (pedestrians, cyclists, wildlife, etc.) were detected, isolated targeted are illuminated isolated to the driver's attention to focus on these objects.

The headlight 1 includes a housing 2 , which preferably consists of an opaque material, in particular plastic. The headlight 1 is arranged at an arbitrary position on the outside, preferably in the front region of the motor vehicle in a corresponding installation opening. In a light exit direction 3 shows the case 2 a light exit opening 4 on, passing through a cover 5 is closed. The cover 5 preferably consists of a transparent material, for example. Glass or plastic. The cover 5 is formed in the example without optically active elements (eg prisms or cylindrical lenses). It would also be conceivable that the cover 5 at least partially provided with optically active elements. At any position are inside the case 2 one or more light modules 6 arranged, which are shown here only schematically. These serve either individually or together to generate the light distribution of the headlamp 1 or part of the light distribution. Except the light modules 6 is in the case 2 also a lighting module 7 arranged, which is designed to realize any lighting function (eg flashing light, daytime running lights, parking or position light) and will be explained in more detail below. Of course, the lighting module 7 even without one or more light modules 6 in the case 2 a lighting device 1 be arranged. Furthermore, the lighting device 1 also be designed as a motor vehicle light.

The luminaire module 7 includes a light guide assembly according to the invention 10 as stated below on the basis of 2 to 4 is explained in more detail.

The light guide arrangement 10 includes a flat lens 11 from a solid transparent material, preferably plastic (eg PC or PMMA). In the 2 to 4 is the lens 11 shown in section. The surface extension of the lens 11 extends perpendicular to the drawing plane. The lens 11 is in a light coupling section 12 , which is a light entry surface 13 includes, over the largely parallel light 14 in the lens 11 is coupled, and a Lichtauskoppelabschnitt 15 divided, in which the coupled light beams 16 by total reflection at interfaces of the decoupling section 15 propagate and at least one light exit surface 17 from the lens 11 be decoupled.

The coupling section 12 has an upper lid surface 18 and a lower floor surface 19 on. Accordingly, the decoupling section 15 an upper lid surface 20 and a lower floor surface 21 on. The lid surfaces 18 . 20 and the floor surfaces 19 . 21 of each section 12 . 15 are plane-parallel to each other and form interfaces of the lens 11 , A circumferential edge surface connects the interfaces 18 - 21 together. The light entry surface 13 of the coupling-in section 12 is part of the border area. The light exit surface 17 the decoupling section 15 is through one or more of the interfaces 20 . 21 educated. The coupling section 12 and the decoupling section 15 each have an areal extent, both perpendicular to the plane of the drawing and parallel to the interfaces 18 - 21 run.

The exit surface 17 are decoupling elements 22 assigned to the light rays impinging on them 23 over the exit surface 17 from the lens 11 couple out. The decoupling elements 22 may be formed, for example, as prisms or wedges. In this case, the decoupling elements 22 on the exit surface 17 each opposite interface 20 . 21 be arranged and designed such that the decoupling elements 22 at least part of the light rays striking it 24 by total reflection in such a way deflect (reflect) that for these light beams 24 when hitting the opposite interface 20 . 21 the conditions for total reflection are no longer met and they are called rays of light 23 from the lens 11 escape. This is in 3 shown. Alternatively, the decoupling elements 22 on the exit surface 17 forming interface 20 . 21 be arranged and designed such that at least for a part of the decoupling 22 incident light rays 24 the conditions for total reflection are no longer met and these rays of light 24 when hitting the decoupling elements 22 as light rays 23 from the lens 11 escape. This is in 4 shown.

According to the invention, the lens 11 designed in a special way to increase the efficiency of the extraction of light from the lens 11 To improve, so that even bright lighting functions (eg daytime running lights or flashing) solely by the light from the lens 11 decoupled light can be generated.

In this sense, for example, run the coupling section 12 and the decoupling section 15 or their surface extensions at an angle α obliquely to each other. The angle α is here, unlike in optics usually not measured against the Flächenlot. The angle α is smaller than a critical angle of total reflection for that for the lens 11 used material. Preferably, the angle α is <45 °, most preferably <10 °. The angle α between the coupling section 12 and the decoupling section 15 the lens 11 causes that in the coupling section 12 coupled largely parallel light rays 14 parallel to the lid surface 18 and the floor area 19 of the coupling-in section 12 propagate in this, in the main propagation direction (in z Direction) over a length 1 (see. 2 ) on the to the coupling section 12 adjacent interface 20 . 21 the decoupling section 15 to meet. In other words, is 1 the way, along the lens 11 after which a ray of light returns to the appropriate area 20 . 21 meets. The decoupling elements 22 have an extension a in the main propagation direction z. In the decoupling section 15 are so many decoupling elements 22 arranged that the sum of the extent a of all decoupling elements 22 in the main propagation direction z greater than or equal to the length 1 is. decoupling 22 which are in the main propagation direction z other decoupling elements 22 are arranged downstream, are arranged so that they are not in the shadow of preceding decoupling elements 22 lie. That over the exit surface 17 from the lens 11 decoupled light alone generates the luminaire function of the lighting device 1 ,

$$\text{l}=2\cdot \text{d/tan}\left(\mathrm{\alpha }\right).$$

In the embodiment shown, a distance b between the lid surface 18 and the floor area 19 of the coupling-in section 12 the lens 11 greater than a distance d between the lid surface 20 and the floor area 21 the decoupling section 15 the lens 11 , Between the lid surface 18 of the coupling-in section 12 and the lid surface 20 the decoupling section 15 runs a kink 25 , Accordingly, runs between the bottom surface 19 of the coupling-in section 12 and the floor area 21 the decoupling section 15 a kink 26 , In particular, the lens is 11 designed such that the distance b between the lid surface 18 and the floor area 19 of the coupling-in section 12 the lens 11 chosen so that the kink 25 the lid surfaces 18 . 20 exactly opposite half the length 1 So, at 1/2, on the floor surface 21 the decoupling section 15 is arranged (see. 1 ) In the light guide assembly 10 the following relationships apply: $$\text{b}=2\cdot \text{d / cos}\left(\mathrm{\alpha }\right).$$

$$\text{l}=2\cdot \text{d / tan}\left(\mathrm{\alpha }\right),$$

The decoupling elements 22 are preferably all on either the top lid surface 20 or on the lower floor surface 21 the decoupling section 15 the lens 11 arranged. It is conceivable that the decoupling section 15 the lens 11 is curved, wherein at each point of the curved Auskoppelabschnitts a section of the lid surface 20 or the floor area 21 exists, which runs along a straight line. In this case, the decoupling section would be 15 that is, bent around a straight line perpendicular to the plane of the drawing.

To the parallel light 14 to generate that via the light entry surface 13 in the coupling section 12 in the lens 11 occurs, the light guide assembly 10 a focusing optical element (not shown), which is formed, which emitted by at least one light source and via the light entry surface 13 in the coupling section 12 the lens 11 to be coupled light beams 14 largely to collimate. The focusing element may, for example, be designed as an attachment optics or a so-called slit light. An attachment optics is a transparent solid body made of glass or plastic (eg PC or PMMA) with a light entrance surface, a light exit surface and interfaces between them, whereby the attachment optics achieves a bundling of light by refraction at the light entry and exit as well as total reflection at the interfaces. A Slit-Light is, for example, from the US 2012/0 075 876 A1 is known there and described in detail by the structure and operation. Reference is made to the corresponding passages of this document. Preferably, the focusing optical element is in a component with the lens 11 educated.

It is conceivable that the decoupling elements 22 are oriented and / or shaped differently in order to specifically shape the luminaire function with regard to legal requirements and customer-specific wishes. Furthermore, it is conceivable that decoupling elements 22 which are in the main propagation direction 2 other decoupling elements 22 are arranged downstream, are formed larger than previous decoupling elements 22 , So can the rear coupling element 22 partially extend over a shaded area. In this case, it becomes more likely that the desired amount of light even with small angular deviations (eg due to not quite parallel light 14 ; Bumps on the interfaces 20 . 21 ; Variation of thicknesses b . d the lens 11 , etc.) still on the decoupling element 22 meets and out of the lens 11 can be disconnected.

Finally, it is also conceivable that the decoupling elements 22 are arranged such that by the decoupling elements 22 decoupled light 23 specifically generates a luminous pattern.

The cross section of the coupling section 12 coupled light beam with parallel light rays 14 has in a sectional plane perpendicular to the top and bottom surfaces 18 . 19 (corresponds to the areas F1 . F2 in the 2-4 ) the extent b , The Rays 14 of the beam strike the interface at an angle α F1 where it is reflected by total reflection. Due to the oblique angle of incidence α the rays hit 14 of the beam on the length 1 on the surface F1 , The second interface F2 the disc 11 begins (in the kink 25 ) at a distance 1/2 from the first point of impact of the beam (in the kink 26 ) along the z-direction at a distance d to the surface F1 ,

If the disc 11 like in the 2-4 is constructed, it is ensured that the initially parallel light beams 16 of the beam between the two surfaces F1 and F2 be guided by total reflection and at each point of the surfaces F1 and F2 a ray of light 16 incident on the surfaces at the angle α.

Due to the coupling of light to the decoupling elements 22 falls in the course of the lens 11 (in the main propagation direction z ) no longer at every point a ray of light 16 on the surfaces F1 and F2 , If a decoupling element 22 along a main propagation direction z the lens 11 in z Direction an extension a has, missing in the further course, the proportion a / 1 in the light beam. If now several decoupling elements along the longitudinal extent of the lens 11 in the z Direction can be introduced, the decoupling elements 22 decouple the complete light bundle in a controlled manner, as long as the total extent of all decoupling elements 22 in the z Direction is greater than or equal to the length 1 is and the decoupling elements 22 not in the "shadow" of previous decoupling elements 22 lie. Furthermore, it should be avoided that the decoupling elements 22 at a distance 1 to each other or an integer multiple thereof are arranged, for example, with respect to the center of the decoupling elements 22 ,

The decoupling elements 22 do not have to be of uniform size or shape. They can be designed individually and on one or both surfaces F1 and F2 be arranged distributed, with the aim to produce the predetermined light distribution of the lighting function. The decoupling elements 22 can be virtually random about the disk 11 be distributed, provided a decoupling element 22 not in the shadow of another.

It is also conceivable that the decoupling elements 22 or their reflective or refractive surfaces are oriented differently, so that a light distribution of the lighting function not only by the scattering of a single decoupling element 22 but by the sum of the individual decoupling elements 22 decoupled light is generated.

Slight deviations from the specification of intersecting straight lines of the lens 11 can be tolerated in principle. So can by a differential dependence of the surfaces F1 and F2 be assured that on every point of the surfaces F1 and F2 Light hits with a defined angle of incidence.

At flat angles of incidence α there are high demands on the quality of the surfaces F1 and F2 , therefore, should be strong variations in the layer thickness b . d the disc 11 avoided if possible.

To improve the tolerance situation in the lens 11 can the light rays 14 of the initially coupled-in light bundle may also be slightly divergent. In order to improve the tolerance situation, the decoupling elements located in the beam path can also be used 22 be made larger than the outboard decoupling elements 22 , So can the rear coupling element 22 partially extend over shaded areas on which no more light falls, as this has been decoupled from previous decoupling elements already from the lens. In this case, it is more likely that the desired amount of light still hits the decoupling element even with small angular deviations.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 2012/0075876 A1 [0003, 0021]

Claims (16)

Optical waveguide arrangement (10) for use in a motor vehicle lighting device (1), comprising a flat lens (11) of a solid transparent material, with an upper cover surface (18, 20), a lower bottom surface (19, 20) parallel to the cover surface (18, 20) , 21) and an edge surface which connects the cover surface (18, 20) to the bottom surface (19, 21), wherein a partial region of the edge surface comprises a light entry surface (13) of the light disc, via which light (14) into the light disc (11). can be coupled in, so that the light (16) by total reflection on the cover surface (18, 20) and the bottom surface (19, 21) propagates in a main propagation direction (z) in the lens (11), and at least partial areas of the cover surface (18, 20) and / or the bottom surface (19, 21) form a light exit surface (17) of the lens (11), via the light in the lens (11) propagating light (24) from the lens (11) emerges, wherein the exit surface (17) decoupling elements (22) are associated with the incident light beams (24) via the exit surface (17) decouple from the lens (11), characterized in that a the light entry surface (13) comprehensive coupling portion (12) of the lens ( 11) relative to the remaining part of the lens (11) which forms a decoupling section (15) of the lens (11) is bent by an angle (α) which is smaller than the critical angle of total reflection in the material of the lens (11) is, so that in the coupling-in section (12) coupled substantially parallel light beams (16) parallel to the cover surface (18) and the bottom surface (19) of the coupling portion (12) propagate therein, in the main propagation direction (z) over a length (1) meet the cover surface (20) or bottom surface (21) of the coupling-out section (15) adjoining the coupling-in section (12) in such a way that the coupling-out elements (22) in the main propagation direction (FIG. z) have an extent (a) such that in the outcoupling section (15) so many outcoupling elements (22) are arranged such that the sum of the extent of all outcoupling elements (22) in the main propagation direction (z) is greater than or equal to the length (1) , wherein decoupling elements (22) which are arranged in the main propagation direction (z) downstream of other decoupling elements (22), are arranged so that they are not in the shadow of preceding decoupling elements (22), and that on the exit surface (22) of the Lens (11) coupled-out light (23) alone generates a luminaire function of the illumination device (1). Optical fiber assembly (10) according to Claim 1 , characterized in that the decoupling elements (22) are arranged on the outlet surface (17) in each case opposite bottom surface (21) or cover surface (20) and are formed such that the decoupling elements (22) at least a portion of the incident thereon light beams (24 ) deflect by means of total reflection such that for these light beams (24) when hitting the opposite cover surface (20) or bottom surface (21) the conditions for total reflection are no longer satisfied and they emerge from the lens (11). Optical fiber assembly (10) according to Claim 1 , characterized in that the decoupling elements (22) on the exit surface (17) are arranged and formed so that at least for a part of the decoupling elements (22) incident light beams (24) the conditions for total reflection are no longer met and these light beams (24) emerge from the lens (11) when hitting the decoupling elements (22). Light guide arrangement (10) according to one of Claims 1 to 3 , characterized in that the angle (α) is less than 45 °, preferably less than 10 °. Light guide arrangement (10) according to one of Claims 1 to 4 , characterized in that a distance (b) between the lid surface (18) and the bottom surface (19) of the coupling portion (12) of the lens (11) is greater than a distance (d) between the lid surface (20) and the bottom surface ( 21) of the coupling-out section (15) of the lens (11). Optical fiber assembly (10) according to Claim 5 , characterized in that between the cover surface (18) of the coupling-in section (12) and the cover surface (20) of the coupling-out section (15) and between the bottom surface (19) of the coupling-in section (12) and the bottom surface (21) of the coupling-out section (15) in each case a kink (25, 26) runs, wherein the distance (b) between the cover surface (18) and the bottom surface (19) of the coupling-in section (12) of the lens (11) is selected such that the kink (25) of the cover surfaces (18, 20) is arranged exactly opposite half of the length (l) on the bottom surface (21) of the Auskoppelabschnitts (15). Optical fiber assembly (10) according to Claim 5 or 6 , characterized in that the following relationships apply in the optical waveguide arrangement (10): $$\text{b}=2\cdot \text{d / cos}\left(\mathrm{\alpha }\right).$$

$$\text{l}=2\cdot \text{d / tan}\left(\mathrm{\alpha }\right),$$

Light guide arrangement (10) according to one of Claims 1 to 7 , characterized in that the decoupling elements (22) all either on the upper cover surface (20) or on the lower Bottom surface (21) of the Auskoppelabschnitts (15) of the lens (11) are arranged. Light guide arrangement (10) according to one of Claims 1 to 8th , characterized in that the decoupling portion (15) of the lens (11) is curved, wherein at each point of the curved Auskoppelabschnitts (15) a section of the lid surface (20) or the bottom surface (21) exists, which runs along a straight line. Light guide arrangement (10) according to one of Claims 1 to 9 , characterized in that the optical waveguide arrangement (10) has a focusing optical element which is designed to largely collimate the light beams emitted by at least one light source and to be injected via the light entry surface (13) into the coupling section (12) of the light disc (11). Optical fiber assembly (10) according to Claim 10 , characterized in that the focusing optical element is formed in a component with the lens (11). Light guide arrangement (10) according to one of Claims 1 to 11 , characterized in that the decoupling elements (22) are formed as prisms or wedges. Light guide arrangement (10) according to one of Claims 1 to 12 , characterized in that the decoupling elements (22) are oriented differently and / or shaped to specifically shape the luminaire function in terms of legal requirements and customer-specific wishes. Light guide arrangement (10) according to one of Claims 1 to 13 , characterized in that outcoupling elements (22) which are arranged downstream of other outcoupling elements (22) in the main propagation direction (z) are designed to be larger than previous outcoupling elements (22). Light guide arrangement (10) according to one of Claims 1 to 14 , characterized in that the decoupling elements (22) are arranged such that the decoupled by the decoupling elements (22) light selectively generates a luminous pattern. Motor vehicle lighting device (1) comprising a housing (2) with a light exit opening (4) directed in the light exit direction (3), which is closed by a transparent cover panel (5), and a luminaire module (7) arranged in the interior of the housing (2) for generating a predetermined luminaire function, in particular a daytime running light or a flashing light, characterized in that the luminaire module (7) has an optical waveguide arrangement (10) according to one of the preceding claims.

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