The invention relates to a headlight lens for a vehicle headlight, for example a motor vehicle headlight, and to a vehicle headlight. The invention furthermore relates to a method of manufacturing a headlight lens or a motor vehicle headlight.
Headlight lenses are employed, for example, in projection-type headlights for motor vehicles and special-purpose vehicles. According to the “Kraftfahrtechnisches Taschenbuch”—Bosch, 22nd edition, ISBN 3-540-62219-5, pages 704-707, for example the last picture on page 707, such headlights are also referred to as PES headlights. Here, a shutter is arranged between a light source and a headlight lens, the shutter having an upper edge which is imaged as a bright-dark boundary by means of the headlight lens.
DE 10 2004 043 706 A1 discloses an optical system for a motor vehicle headlight for distributing a light beam bundle of a lamp, wherein a primary optical element having an optical face with a discontinuity extending along a line is provided, wherein the optical face is smooth at least on one side adjacent to the discontinuity so that the light beam bundle is divided into two partial light beam bundles. Here, at least one of the partial light beam bundles has a sharp boundary edge which is imaged onto a predetermined bright-dark boundary by means of an optical secondary element.
EP 1 630 576 A2 discloses a headlight with a light source and a secondary lens arranged subsequent of the light source in a direction of beam, wherein a primary optical element with a light entry and a light exit is arranged between the light source and the secondary lens, which is designed such that an emission characteristic corresponding to a provided emission characteristic is generated by means of the secondary lens by selective reflections in the primary optical element and a selective projection of the light exit or an imaginary face located in a beam path of the light emitted by the light source.
WO 2015/061822 A1 discloses an illumination device for a motor vehicle headlight wherein the illumination device comprises at least one optical body and at least one mounting device for the at least one optical body, wherein the at least one optical body comprises a number of adjacently arranged auxiliary optical systems, each auxiliary optical system comprising a face for coupling in light and a face for coupling out light, wherein the at least one mounting device comprises at least one seat for each auxiliary optical system, and wherein the seats are defined by boundary walls, wherein the boundary walls comprise, on the side of the light exit, boundary edges which are imaged in a light distribution created by the at least one optical body as bright-dark edges between the partial light distributions created by the individual auxiliary optical systems, and wherein a secondary projection lens is arranged subsequent of the at least one optical body in a light exit direction.
An embodiment concerns a monolithic headlight lens for a vehicle headlight with a light source, for example for a motor vehicle headlight, wherein the headlight lens comprises a light entry face and a light exit face through which light that has entered into the light entry face exits from the headlight lens (with a bright-dark boundary or generating a bright-dark boundary), wherein
In an embodiment of the invention, the headlight lens consists of inorganic glass. Inorganic glass in the sense of the disclosure is for example silicate glass. Inorganic glass in the sense of the disclosure is for example glass as it is described in PCT/EP2008/010136. Inorganic glass in the sense of the disclosure for example comprises:
In a further embodiment of the invention, the headlight lens is limited by a marginal area between the light entry face and the light exit face, wherein the marginal area is not provided as a TIR face. In this sense, the headlight lens is for example no light conductor in which light distribution is generated by TIR and then exits from a light exit face. The bright-dark boundary is for example exclusively generated by (the relation between the light entry face and) the light exit face, wherein neither a shutter nor any optical structure for generating a bright-dark boundary, or which is imaged as a bright-dark boundary, is provided.
It may be intended that a light entry face in the sense of the disclosure and/or a light exit face in the sense of the disclosure comprises a light scattering structure. A light scattering structure in the sense of the disclosure may be e. g. a structure as it is disclosed in DE 10 2005 009 556 Al and EP 1 514 148 A1 or EP 1 514 148 B1.
Another embodiment concerns a vehicle headlight comprising a headlight lens including one or several ones of the aforementioned features, wherein the vehicle headlight does not comprise any secondary optical system for imaging the headlight lens or the light exit face of the headlight lens or a light beam exiting from the light exit face of the headlight lens. The vehicle headlight moreover comprises a light source for irradiating light into the light entry face. A light source in the sense of the disclosure may comprise an actual light source or a light source with a reflector. It may be intended that the light source is connected with the light entry face or that the light entry face is coated with the light source. It may also be intended that the light source is arranged following the contour of the light entry face at a small distance from the light entry face. A small distance in this sense may be, for example, a distance of no more than 2 mm or no more than 1 mm.
A light source in the sense of the disclosure is for example a surface light emitter or for example a directed surface light emitter. A light source in the sense of the disclosure is e. g. an LED layer or an OLED layer. A light source in the sense of the disclosure is for example a directed layer or light source, a directed LED, or a directed OLED. A suited layer or light source is disclosed, for example, in WO 2008/121414 A1 (incorporated by reference in its entirety). A light source in the sense of the disclosure e. g. comprises a transparent electrode and an, for example reflective, electrode. Between the transparent electrode and the, for example reflective, electrode, for example a light-emitting layer or a light layer is arranged which comprises, for example, a first region comprising an organic emitting material, and a second region comprising a low-index material having an index of refraction that is smaller than the index of refraction of the (organic) emitting material, wherein the second region is arranged adjacent to the first region. In an embodiment, the low-index material has an index of refraction of 1.0 to 3.0. In a further embodiment of the invention, the low-index material has an index of refraction of 1.0 to 1.5. In a further embodiment of the invention, the low-index material forms a grid which is oriented in a plane parallel to the transparent electrode and to the (reflective) electrode. In a further embodiment of the invention, the grid is designed with a periodicity that is greater than the wavelength of light. In a further embodiment of the invention, the periodicity is not greater than five times the width of the grid lines. In a further embodiment of the invention, the periodicity is not greater than four times the width of the grid lines. In a further embodiment of the invention, the periodicity is not greater than three times the width of the grid lines. In a further embodiment of the invention, the low-index material consists of or comprises an aerogel, Teflon, graded thin-film SiO2, graded thin-film TiO2, and/or sheets of SiO2 nanorods. A light source in the sense of the disclosure may be a FOLED. Examples of FOLEDS may be taken from WO 98/07173 (incorporated by reference in its entirety) and the Internet site oled.com/oleds/flexible-oleds-foleds/ (incorporated by reference in its entirety).
Another embodiment concerns a motor vehicle comprising a headlight lens with one or several ones of the aforementioned features or a vehicle headlight with one or several ones of the aforementioned features.
Another embodiment concerns a method of manufacturing a headlight lens comprising one or several ones of the aforementioned features, wherein a light entry face of the headlight lens and a light source for irradiating light into the light entry face are selected, wherein a light distribution (flux density or intensity distribution) is selected on a target face onto which the light of the light source is directed by means of the headlight lens, wherein the light (or its flux density or intensity distribution) entering into the light entry face of the headlight lens (for example by means of a Jacobian matrix or the determinant of the Jacobian matrix) is related to the light distribution (flux density or intensity distribution) on the target face in the form of a differential equation, and wherein the differential equation is resolved for a coordinate describing the shape of the light exit face of the headlight lens.
An aforementioned light distribution is for example an intensity distribution. Intensity or intensity distribution refers to power or luminous power. Power is to be understood as energy per area and time unit. Power in the sense of the disclosure is for example the flux density.
It is for example intended that the desired light distribution on the target face comprises a bright-dark boundary limiting the light to the top. It is for example intended that the bright-dark boundary comprises at least one bend, for example at least two bends.
In a further embodiment of the invention, a surface of the headlight lens between the light entry face and the light exit face that connects the light entry face and the light exit face is selected, wherein it is for example intended that the surface is not provided or equipped as a TIR surface.
In a further embodiment of the invention, the differential equation is a second-order differential equation.
In a further embodiment of the invention, a headlight lens whose light entry face corresponds to the selected light entry face and whose light exit face corresponds to the calculated light exit face is manufactured.
In a further embodiment of the invention, a mold having a first mold face for molding a surface corresponding to the (negative of the) selected light entry face of the headlight lens, and having a second mold face for molding a surface corresponding to the (negative of the) calculated light exit face of the headlight lens is manufactured, wherein a headlight lens is pressed by means of the mold. Here, it is for example intended that a blank or a gob is heated or its temperature gradient is reversed, and the hot gob is press-molded between the two molds. The blank or the gob for example consists of inorganic glass.
A motor vehicle in the sense of the disclosure is for example a land craft to be individually used in road traffic. Motor vehicles in the sense of the disclosure are for example not restricted to land crafts with an internal combustion engine.
The method of manufacturing the headlight lens 1 described in
A step 13 follows where a target face ZF to be illuminated (screen, wall) and the flux density or intensity distribution Oout(X,Y) to be achieved or that is desired on this target face ZF are selected (cf. for example ECE R112), wherein X and Y are the coordinates on the target face. The flux density or intensity distribution Iout(X, Y) to be achieved or that is desired is here selected such that the light impinges on the target face ZF (essentially) below a bright-dark boundary. It may also be intended that the coordinates are stated as polar coordinates. This is for example if the desired light distribution is selected in the sense of ECE R112.
A step 14 follows where the flux density or the intensity distribution of the light that enters into the light entry face 3 of the headlight lens 1 is related with the flux density or intensity distribution on the target face ZF by means of a Jacobian matrix in the form of a differential equation:
I
out(X,Y)·|J|=Iin(x,y)
wherein the Jacobian matrix is
The coordinates X and Y are a function of x, y, ∇z, wherein ∇ designates the 2-D gradient. That means ∇z is the gradient of the surface function z=z(x,y) in Cartesian coordinates, and r=r(ϕ,θ) in spherical coordinates. The place R=(X, Y) of the impingement of a light beam onto the target face ZF depends on the index of refraction and the oblique position of the light exit face 4 of the headlight lens 1, wherein the oblique position of the light exit face 4 is characterized by the 2-D gradient so that the following second-order differential equation results:
I
out(x,y,∇z)·|J(x,y,∇2z)|=Iin(x,y)
Here, the first derivation indicates where the light impinges on the target face ZF, and the second derivation, which corresponds to the curvature of the face, indicates how much light impinges on the target face at said point.
A step 15 follows where the second-order differential equation (Monge-Ampère equation) is resolved for z
I
out(x,y,∇z)·|J(x,y,∇2z)|=Iin(x,y)
The function z(x,y) defines the light exit face 4 of the headlight lens 1 (cf. e. g. Adam M. Oberman: “Convergent difference schemes for degenerate elliptic and parabolic equations: Hamilton-Jacobi equations and free boundary problems”, SIAM J. Numer. Anal., 44:879-895, 2006; Froese, B. D.: “A numerical method for the elliptic Monge-Ampère equation with transport boundary conditions”, SIAM J. Sci. Comput., 34, 2012; B. D. Froese, A. M. Oberman: “Convergent finite difference solvers for viscosity solutions of the elliptic Monge-Ampère equation in dimensions two and higher”; SIAM Journal on Numerical Analysis, 49, January 2011; J.-D. Benamou, B. D. Froese, A. M. Oberman: “Numerical solution of the Optimal Transportation problem using the Monge-Ampère equation”, Journal of Computational Physics, 260, March 2014).
In a following step 16, a marginal area between the margin of the light entry face 3 and the margin of the light exit face 4 is selected, insofar as the margins of the light entry face 3 and the light exit face 4 do not touch.
In a subsequent step 17, a headlight lens 1 with the selected light entry face 3 and the determined light exit face 4 is manufactured or produced, respectively. In a subsequent step 18, the headlight lens 1 is installed in a low-beam vehicle headlight together with a non-punctiform light source whose light enters into the light entry face 3 and exits through the light exit face 4 from the headlight lens 1. Here, for example a modified method represented in
The modified method according to
The enlarged light entry face is represented in
The enlarged light entry face is represented in
(with Schirm=screen, Linse=lens) The increase of the light exit face 4E at the margin thus results in:
n
2 sin α=n1 sin(π+arctan m)
with m being the increase in the x-direction, n2 the index of refraction of the material of the headlight lens, and n1 the index of refraction of air. The thickness of the headlight lens is irrelevant.
Step 27 follows where the headlight lens 1E is manufactured with the light entry face 3E and the light exit face 4E. In a subsequent step 28, the headlight lens 1 is installed in a low-beam vehicle headlight together with a light source designed as a surface light emitter whose light enters into the light entry face and exits from the headlight lens through the light exit face.
It may be intended to consider an oblique fitting position in a motor vehicle when determining the light exit face. Correspondingly,
The arrows in
If in this application, reference is made to a light entry face or a light exit face, for example the contour of the light entry face or the contour of the light exit face is meant if no explicit reference is made to surface (micro-) structures as in the last but one paragraph on page 3.
Due to its low installation depth, headlights according to the invention are particularly suited to be installed in the vehicle's middle or in the middle third of the vehicle and/or in the shock absorber. Headlights according to the invention are particularly suitably installed, for example, at the positions 3001, 3002, 3003 and 3004 indicated in U.S. Pat. No. 9,243,769 B2 (incorporated by reference in its entirety).
The disclosure provides for a headlight lens for an alternative headlight concept. It for example desirable provides for a headlight concept or a headlight lens for such a headlight concept that differs from aforementioned headlight concepts. It furthermore for example provides for improved light efficiency or efficiency in the utilization of the luminous power of a light source. It furthermore provides for a headlight concept that permits the reduction of manufacturing costs at least as compared to aforementioned headlight concepts, at least, however, as compared to conventional projection-type headlights or PES headlights.
Number | Date | Country | Kind |
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10 2016 009 067.7 | Jul 2016 | DE | national |
This application is a U.S. national counterpart application of international application serial No. PCT/EP2017/000677, filed Jun. 9, 2017, which claims priority to German Patent Application No. 102016009067.7 filed Jul. 27, 2016.
Filing Document | Filing Date | Country | Kind |
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PCT/EP2017/000677 | 6/9/2017 | WO | 00 |